APPARATUS, OPTICAL ASSEMBLY, METHOD FOR INSPECTION OR MEASUREMENT OF AN OBJECT AND METHOD FOR MANUFACTURING A STRUCTURE

Description

Background

[0001] Laser radar is a versatile metrology system that offers non-contact and true single- operator inspection of an object (often referred to as a target). Laser radar metrology provides object inspection that is particularly useful in acquiring high quality object inspection data in numerous industries, such as aerospace, alternative energy, antennae, satellites, oversized castings and other large-scale applications.

[0002] Known concepts for Laser radar systems are disclosed in US Patents 4,733,609, 4,824,251, 4,830,486, 4,969,736, 5,114,226, 7,139,446, 7,925, 134, and Japanese Patent #2,664,399. The laser beam from the laser radar system (referred to herein as the "measurement beam") is controlled by the laser radar system optics, and is directed from the laser radar system and at the target. The laser beam directed from the laser radar system may pass through a splitter which directs the laser beam along a measurement path and at the target, and splits off a portion of the laser beam to a processing system that is disclosed in US Patents 4,733,609, 4,824,251, 4,830,486, 4,969,736, 5,114,226, 7,139,446, 7,925,134, and Japanese Patent #2,664,399. The laser beam directed along the measurement path is reflected from or scattered by the target, and a portion of that reflected or scattered laser beam is received back at the laser radar system, where it is detected and processed to provide information about the target. The detection and processing of the reflected or scattered light is provided according to US patents 4,733,609, 4,824,251, 4,830,486, 4,969,736, 5,114,226, 7,139,446, 7,925,134, and Japanese Patent #2,664,399. The present invention is directed at the optical assembly by which a pointing beam and measurement laser beam are transmitted from the laser radar system Other optical measurement systems forming part of the state of the art include those disclosed in JP 2006 194846 A and US 2007/058154 A1.

[0003] An existing laser radar system has a relatively large rotating scanning (pointing) mirror, that rotates relative to other parts of the laser radar system, and is used to achieve beam pointing. This mirror causes system instability and polarization issues. The existing system is also not achromatic, so the two wavelengths (e.g. the pointing beam wavelength and the measurement beam wavelength) cannot be focused on a part in space simultaneously. In addition, the existing system limits the field of view of the camera that is pointed in the same direction as the laser radar.

Summary of the present invention

[0004] The present invention has been made taking the circumstances as described above into consideration.

[0005] According to a first aspect of the present invention, there is provided a laser radar apparatus as recited in claim 1 below.

[0006] According to a second aspect of the present invention, there is provided a method for manufacturing a structure as recited in claim 9 below.

[0007] The dependent claims are directed to particular aspects of the claimed invention.

[0008] Additional features and advantages of particular embodiments of the various aspects of the present invention will become apparent from the following detailed description and the accompanying drawings.

Brief Description of the Drawings

[0009] 

Figure 1 is a schematic illustration of a laser radar system, of a type that can employ an optical assembly according to embodiment;

Figure 2 is a front view of a preferred type of laser radar system that can employ an optical assembly according to embodiment;

Figures 3(A), 3(B) and 3(C) are examples of different versions of an optical assembly which is not in accordance with the claimed invention, but which is useful for understanding the claimed invention;

Figure 4 shows the catadioptric portion of another example of an optical assembly which is not in accordance with the claimed invention, but which is useful for understanding the claimed invention;

Figure 5 illustrates certain performance capabilities of such optical assemblies; and

Figure 6 illustrates additional performance capabilities of such optical assemblies.

Figure 7a is a schematic illustration of one version of an optical assembly which itself is not in accordance with the claimed invention, but which can be implemented according the claimed invention;

Figure 7b is a fragmentary, schematic illustration of the optical assembly of Figure 7a, showing the reflection schema provided by the corner cube and the plane mirror;

Figures 8a and 8b are schematic side and top illustrations of second version of an optical assembly not in accordance with the claimed invention, but which is useful for understanding the claimed invention;

Figure 8c is a fragmentary, schematic illustration of the optical assembly of Figures 8a and 8b, showing the reflection schema provided by the reflective roofs of those elements; and

Figures 9-13 are schematic illustration of additional concepts of an optical assembly which implements the claimed invention.

Figure 14 is a block diagram of a structure manufacturing system 700; and

Figure 15 is a flowchart showing a processing flow of the structure manufacturing system 700.

Detailed Description

[0010] Examples of a laser radar system 100 will be explained below with reference to the drawings. However, the present invention is not limited thereto.

[0011] The present disclosure provides a compact optical assembly (sometimes referred to as an Integrated Optical Assembly, or IOA), that is useful in a laser radar system, and is also useful in various other optical systems.

[0012] In a laser radar system, the optical assembly is configured to move as a unit with the laser radar system, as the laser radar system is pointed at a target and eliminates the need for a large scanning (pointing) mirror that is moveable relative to other parts of the laser radar system.

[0013] The optical assembly is designed to be compact, and to utilize a relatively simple assembly of elements for directing and focusing a pointing beam and a measurement beam at an outlet of the optical radar system.

[0014] An optical system herein disclosed comprises catadioptric optical optics that is moveable as a unit with the laser radar, and directs both a pointing beam and a measurement beam at a target at which the laser radar system is pointed, while eliminating the need for a scanning (pointing) mirror that is moveable relative to other components of the laser radar to direct the pointing beam. The pointing beam is produced in a visible (e.g. red such as around 610 nm to 750 nm) wavelength range, and the measurement beam is produced in a different, predetermined wavelength range (e.g. infrared such as around 0.7 µm to 10 µm, or IR). The pointing and measurement beams are handled by the compact optical assembly of the present embodiment which moves as a unit with the laser radar system, to direct the pointing and measurement beams from the laser radar system (and at the target), in a manner that avoids use of a scanning (pointing) mirror that is moveable relative to other components of the laser radar.

[0015] The optical assembly includes catadioptric optics that include a concave mirror that provides most of the optical power, and allows easier achromatization between the two required wavelengths. The concave mirror folds the optical path onto itself, reducing the overall size of the optical assembly substantially. The size of the optical assembly is designed to be small enough to allow a camera to be located on the moving part of the laser radar system, and eliminates parallax effects by use of a reflective window or cold mirror that allows the camera optical axis to be collinear with the axis of the measurement beam. The concave mirror helps achromatize the system, while also folding the optical path to create a compact optical system which allows the entire optical assembly to be rotated as a unit with the laser radar system for scanning, eliminating the expensive and troublesome rotating (pointing) mirror of the existing system.

[0016] Basically, such a system comprises an optical assembly moveable as a unit as part of a laser radar system, and configured to direct a pointing beam and a measurement beam through an outlet of the laser radar system. The optical assembly includes catadioptric optics configured to fold the optical path of the pointing beam and measurement beam that is being directed through the outlet of the laser radar system, to compress the size of the optical assembly.

[0017] Such a system can be implemented in various ways. For example, the optical assembly includes a window with a transmissive portion through which the pointing beam and measurement beam are directed to the outlet of the laser radar system. A relay system directs the pointing beam and measurement beam from an optical fiber to a reflective area of the window, and the catadioptric optics receive and reflect the pointing beam and measurement beam from the reflective area of the window back through a transmissive portion the window, to fold the optical path of the pointing beam and measurement beam that is being directed through the outlet of the laser radar system, to compress the size of the optical assembly. The concave mirror folds the optical path onto itself. In other words, part of the optical path overlaps. As for the optical path for the measurement beam, the optical path between concave mirror and reflective area of the window overlaps. In other words, optical assembly has more than two directions of a light from light source.

[0018] In one specific version of such a system, the optical assembly includes at least one moveable optic to vary focus of the pointing beam and the measurement beam that is reflected by the catadioptric optics and directed back through the transmissive portion of the window. In another specific version, the focus of the pointing beam and measurement beam that is reflected by the catadioptric optics and directed back through the transmissive portion of the window is changed by moving a plurality of optics, the plurality of optics characterized by low optical power but a large amount of spherical aberration.

[0019] In another implementation of such a system the window comprises a cold mirror that transmits light in a predetermined wavelength range that includes the wavelength range of each of the pointing and measurement beams, and an optical fiber that transmits the pointing beam and the measurement beams is located at a central location of the cold mirror. The catadioptric optics receive the pointing beam and the measurement beam from the optical fiber and reflect the pointing beam and the measurement beam back through the cold mirror, where it is directed to the outlet of the laser radar system. The camera 140 is placed such that it accepts light reflected by the coating on cold mirror 122, allowing the line of site of the camera to be collinear with the axis of the measurement and pointing beams. The cold mirror 122 allows the camera optical axis to be collinear with the axis of the measurement beam.

[0020] In one specific version of such a system, the optical assembly includes at least one moveable optic to vary focus of the pointing beam and the measurement beam that is reflected by the catadioptric optics and directed back through the cold mirror. In another specific version, the focus of the pointing beam and measurement beam that is reflected by the catadioptric optics and directed back through the cold mirror is changed by moving a plurality of optics, the plurality of optics characterized by low optical power but a large amount of spherical aberration.

[0021] In some configurations of such a system, the optical assembly is configured to direct a pointing beam and a measurement beam along a line of sight and through an outlet of the laser radar system. The optical assembly comprises a light source, a lens, a scanning reflector and a fixed reflector that co-operate to focus the pointing and measurement beams from the light source along a line of sight that extends through the lens. The light source, the lens, the scanning reflector and the fixed reflector are oriented relative to each other such that the pointing and measurement beams from the light source are reflected by the scanning reflector to the fixed reflector, and reflected pointing and measurement beams from the fixed reflector are reflected again by the scanning reflector and directed along the line of sight through the lens, and the scanning reflector is moveable relative to the source, the lens and the fixed reflector, to adjust the focus of the pointing and measurement beams along the line of sight.

[0022] In some configurations of such a system, the scanning reflector comprises a retroreflector, and the fixed reflector comprises a plane mirror. The source, the lens and the plane mirror are all in fixed locations relative to a support structure for the optical assembly, and the retroreflector is moveable relative to those fixed locations, to vary the focus of the pointing and measurement beams along the line of sight.

[0023] Herein are disclosed various constructions of such a system. In one version, the retroreflector comprises a corner cube that has at least three reflective surfaces that are oriented so that (i) the pointing and measurement beams from the source are reflected through the corner cube to a plane mirror, (ii) the pointing and measurement beams reflected from the plane mirror are again reflected through the corner cube, and (iii) movement of the corner cube in at least one predetermined direction adjusts the focus of the pointing and measurement beams along the line of sight, in a manner that is substantially unaffected by movement of the corner cube in directions transverse to the predetermined direction or by rotations of the corner cube relative to the predetermined direction.

[0024] In one version, the scanning reflector comprises a reflective roof that provides two reflections of the pointing and measurement beams, and the fixed reflector comprises a reflective roof that also provides two reflections of the pointing and measurement beams, where the nodal lines of both reflective roofs are in a predetermined orientation relative to each other.

[0025] The following detailed description also provides concepts for configuring and orienting the components of the optical assembly. Those concepts are designed, e.g. to reduce the weight of the optical assembly, and improve the performance of the optical assembly, while keeping the optical assembly as compact as possible.

[0026] In one concept, the pointing and measurement beams reflected by the scanning reflector and directed along the line of sight through the lens, are reflected by a fold mirror that folds the line of sight of the pointing and measurement beams directed through the lens. The source comprises an optical fiber supported by the fold mirror.

[0027] In another concept, the lens, the beam source and the plane mirror are supported in a manner such that they can move as a unit relative to the retroreflector, and wherein the line of sight moves with the unit.

[0028] In still another concept, the pointing and measurement beams reflected by the scanning reflector and directed along the line of sight through the lens are reflected by a polarization beam splitter that folds the line of sight of the pointing and measurement beams directed through the lens, and wherein the source comprises an optical fiber in a predetermined location relative to the polarization beam splitter that folds the line of sight of the pointing and measurement beams directed through the lens.

[0029] In yet another concept, the source comprises an optical fiber supported by a monolithic member that has a portion that functions as the plane mirror and another portion that folds the line of sight of the pointing and measurement beams reflected by the scanning reflector and directed along the line of sight through the lens.

[0030] In still another concept, the source comprises an optical fiber supported by a transmissive member that also supports the plane mirror.

First Configuration

[0031] As described above, the present disclosure provides an optical assembly that is moveable as a unit with a laser radar system, and is configured to transmit a pointing beam and a measurement beam from the laser radar system, where they can be directed at a target at which the laser radar system is pointed. The present invention is described herein in connection with a laser radar system of the type described in US patents 4,733,609, 4,824,251, 4,830,486, 4,969,736, 5,114,226, 7,139,446, 7,925,134, and Japanese Patent #2,664,399, and from that description, the manner in which the present invention can be implemented with various types of laser radar systems will be apparent to those in the art.

[0032] Figures 1 and 2 show a laser radar system in which the various configurations herein disclosed, including those of the invention, may be implemented. As shown in Figures 1 and 2, a laser radar system 100 produces a point beam in a visible (e.g. red) wavelength range, and a measurement beam in a different (e.g. infrared, TR) wavelength range, and directs (transmits) the pointing and measurement beams to an outlet 120 of the laser radar system. The pointing beam is used to identify a point on a target 106-at which the measurement beam is directed. The laser source of the pointing beam and the measurement beam is different. A control unit can control a laser radar system 100. In this embodiment, the laser radar system 100 has a control unit. However a separate system coupled with the laser radar system 100 may have the control unit.

[0033] The measurement beam may pass through a splitter 102 which directs the measurement beam (and the pointing beam) along a measurement path 104 and at the target 106, and sends a portion of the measurement beam through a circuit 108 where that portion of the laser beam is processed in a manner described in US patents 4,733,609, 4,824,251, 4,830,486, 4,969,736, 5,114,226, 7,139,446, 7,925,134, and Japanese Patent #2,664,399. In Figure 1, that splitter is the bottom splitter identified by 102. The measurement beam directed along the measurement path 104 is reflected from the target 106 and a portion of that reflected or scattered measurement beam is received back at the laser radar system 100, where it is directed to a detector by the top splitter shown in Figure 1, detected and processed to provide information about the target 106. The detection and processing of the reflected or scattered radiation from the measurement beam is provided in a base 110 of the laser radar system 100, and is configured to detect and process the reflected radiation according to US patents 4,733,609, 4,824,251, 4,830,486, 4,969,736, 5,114,226, 7,139,446, 7,925,134, and Japanese Patent #2,664,399. Briefly, optical heterodyne detection provides a source light beam which is directed to a target 106 and reflected therefrom. The return light beam is then mixed with a local oscillator light beam on a photo detector to provide optical interference patterns which may be processed to provide detailed information about the target 106. Optical heterodyne techniques take advantage of the source and reflected light beam reciprocity. For example, these light beams are substantially the same wavelength and are directed over the same optical axis. Measurement path 104 and target path 104 is same. This provides an improved signal-to-noise ratio (SNR) and heightened sensitivity. The SNR is sufficiently high so that a small receiving aperture may be used, in contrast to known direct detection systems. A small receiver aperture may be envisioned as a very small lens capable of being inserted into limited access areas. Since a small receiver aperture can still provide detailed information about the target, the optical components of a coherent system may be made very small and provide related increases in scanning speed and accuracy. For example, a coherent optical system using a one-half inch aperture can obtain more information about a target than a four inch aperture used in a direct optical detection system. The present invention is directed at the optical assembly by which the pointing beam and measurement beam are transmitted to the outlet 120 of the laser radar system.

[0034] In a known laser radar system, a moveable mirror is provided for directing the point beam at a target. The moveable mirror is separate from the optics that transmit the measurement beam, and requires a relatively large laser radar housing to accommodate both the moveable mirror and the laser radar optics. The present invention is relatively compact, because both the measurement beam and pointing beam are produced by a relatively compact optical assembly that can move as a unit with the laser radar system 100. Moreover, the optical assembly of the present invention is designed to be relatively stable in performing its beam transmission/reception functions. An electronic motor is provided for moving the optical assembly. In this embodiment. The optical assembly is movable for two axis relative to different direction. The two axis is located with YX plane and XY plane as shown in Figure 2. The two axis are the Z axis and X axis. The encoder is provided for monitoring the position of the optical assembly. The control unit can control power of the electronic motor by the position of the optical assembly.

[0035] As shown in Figure 2, the laser radar system 100 includes a housing (e.g. a rotatable cylinder 112) in which the optical assembly is located and secured, so that the optical assembly moves as a unit with the cylinder 112 relative to the base 110 of the laser radar system. The laser radar system includes an outlet 120 in the housing 112, and through which radiation (e.g. in the two wavelengths of the pointing and measurement beams) is directed from the laser radar system. The base 110 contains the processing features of the laser radar system, that are disclosed in US patents 4,733,609, 4,824,251, 4,830,486, 4,969,736, 5,114,226, 7,139,446, 7,925,134, and Japanese Patent #2,664,399.

[0036] The basic features of an optical assembly 114 which can be applied in such a system, but which is not an embodiment of the present invention, can be appreciated from Figures 3(A) through 3(C). In Figure 3(A), the optical assembly 114 includes an optical fiber (represented by fiber tip 116) through which a pointing beam and measurement beam are transmitted, a relay system 124 that directs the pointing and measurement beams from the optical fiber 116 to a small reflective area 126 of a window 122 (also referred to as a fold mirror in the embodiments of Figures 3(A) through 3(C)), and catadioptric optics 128 that receive and reflect the pointing and measurement beams from the reflective area 126 of the window 122 back through the window 122, where it is directed through the outlet 120 of the housing 112. The window 122 has a small silvered area on one side that forms the reflective area 126, and a coating on its other side that allows radiation in the red and infrared range to be transmitted through the window and to the output aperture 120. The camera 140 is placed such that it accepts light reflected by the coating on window 122, allowing the line of site of the camera to be collinear with the axis of the measurement and pointing beams. It should be noted that while the location and orientation of camera 140 is shown in Figure 3(A), the camera 140 could be similarly located and oriented relative to the window 122 in the versions of the first embodiments shown in Figures 3(B), 3(C) and 4.

[0037] In addition, the optical assembly 114 is configured to receive at least some radiation that is reflected or scattered from the target 106, and directs that radiation back through the fiber 116. The fiber 116 can have a fiber beam combiner that combines a pointing beam in the visible (e.g. red) wavelength range with the measurement beam in the different, e.g. infrared (IR) wavelength range. The pointing beam and measurement beams are generated from separate sources, and are combined by a fiber beam combiner located inside the base 110 in a manner well known to those in the art.

[0038] The laser radar system 100 has the pointing beam and measurement beam. However, the laser radar system 100 may have the measurement beam without the pointing beam. For example, the measurement beam is in the visible. Therefore, in this case, the measurement beam can also be the pointing beam. The laser radar system 100 of this embodiment has the different wavelength region between the pointing beam and measurement beam. However, the laser radar system 100 may have the same wavelength region such as the visible region.

[0039] In Figure 3(A), the optical assembly 114 includes the relay system 124 that directs the pointing and measurement beams from the optical fiber 116 to the small reflective area 126 of the window 122, and catadioptric optics 128 that receive and reflect the pointing and measurement beams from the reflective area 126 of the window 122 back through the transmissive portion of the window 122, where it is directed through the outlet 120 of the housing. The catadioptric optics 128 include a spherical mirror 130 from which radiation (i.e. from the pointing and measurement beams) is reflected and one or more optics through which the radiation is directed. In the embodiment of figure 3(A), the optical assembly includes at least one moveable optic 132 to vary focus of the radiation that is reflected from the spherical mirror 10 and back through the window 122. The optic 132 may be bi concave, or may be plano concave, with at least one concave portion 134 facing the fold mirror 122. The moveable optic 132 is configured to focus the radiation reflected from the spherical mirror 130 at the target, and is also configured for reducing stray radiation reflected by transmissive lens surfaces (ghost images) from being directed back through the fiber 1 16. Specifically, the concave portion 134 of the optic 132 has a center of curvature that is far from the fiber conjugate, to reduce the likelihood of stray radiation reflected by lens surfaces being directed back through the fiber. Also, a lens 135 that is fixed in relation to the optical assembly corrects for spherical aberration, allowing for a diffraction limited focused spot at the target. The spherical mirror folds the optical path onto itself. In other words, part of the optical path overlaps. As for the optical path for the measurement beam, the optical path between concave mirror and reflective area 126 overlaps. In other words the travel direction of light from light source changes in the optical assembly. The direction from reflective area 126 to concave mirror is different from the direction from concave mirror to reflective area 126. In another specific version of the first embodiment, shown in Figures 3B and 3C, the optical assembly includes a set 136 of optics that that can move as a group relative to the spherical mirror 130 and the window 122. In the embodiment of Figures 3B and 3C, the focus of the pointing beam and measurement beam that is reflected by the catadioptric optics and directed back through the window 122 is changed by moving the set 136 of optics, which are characterized by low optical power but a large amount of spherical aberration. Thus, in the example of Figure 3B, the set of optics 136 are relatively close to the window 122 to provide focus at a short distance (e.g. about 1 meter), and in Figure 3C the set of optics 136 are relatively close to the spherical mirror 130 to provide focus at a relatively longer distance (e.g. about 60 meters). The position of the moving group 136 is continuously variable between these two extremes, allowing the measurement beam and pointing beam to be focused at any distance between, for example, 1 and 60 meters from the laser radar optical assembly.

[0040] In yet another specific version, the catadioptric portion of which is shown in Figure 4, window 122 comprises what is known as a "cold mirror" because it transmits radiation the visible red and 1R wavelength ranges of the pointing and measurement beams, and reflects radiation at shorter wavelengths. The optical fiber 116 is located at a hole 137 in a central location of the cold mirror 122, and the catadioptric optics receive the radiation of the pointing and measurement beams from the optical fiber 116 and reflect the radiation back through the cold mirror 122 and to the outlet 120 of the laser radar housing 112, in the manner described in connection with Figures 3A, 3B and 3C. That version can also include the one bi concave or plano concave optic (e.g. as shown at 132 in Figure 3 A) to vary focus of the radiation that is reflected back through the cold mirror (and which has a concave surface 134 with a center of curvature that is far from the fiber conjugate, to reduce stray radiation reflected from the lens surfaces (ghost images) from being directed back through the fiber). Alternatively, that version can include a plurality of moving optics (e.g. as shown at 136 in Figures 3B and 3C) that are configured such that the focus of the pointing beam and measurement beam that is reflected by the catadioptric optics and directed back through the cold mirror 122 is changed by moving the set 136 of optics, which are characterized by low optical power but a large amount of spherical aberration.

[0041] Figure 5 shows an example of the performance of such an optical assembly. In the example of Figure 5, performance is shown at 1, 2, 5, 24, and 60 meters (for the 1R light), where the red light is well focused for all positions. Figure 5 (and exhibit A) show spot diagrams that indicate the level of performance of the optical system, which should be familiar to those in the art. The solid circles in figure 5 (and exhibit A) indicate the diffraction limit as defined by the wavelength and aperture of the laser radar optical system. The diffraction limit represents the best possible performance for this optical system, as is well understood by those in the art. The three plots for each target distance of 1, 2, 5, 24 and 60 meters show the performance as the fiber moves off-axis relative to the catadioptric optical system 128 and/or relay system 124. The three plots for each target distance are for an off-axis distance of 0 mm for the top left, 0.3 mm for the top right and 0.5 mm for the bottom middle. The '+' marks indicate the focused locations of the different rays; if all of these marks are within or close to the circle defining the diffraction limit, then the performance of the lens is diffraction limited, as is well understood by those in the art.

[0042] An important aspect of the laser radar's ability to measure the position of the target in three dimensions is the ability to resolve the spot location in a plane perpendicular to the pointing (optical) axis of the laser radar. This is done by accurately measuring the two pointing angles for the steering assembly that points the entire optical assembly. However, in certain situations, the spatial resolution of the target location in the plane perpendicular to the pointing axis can be limited by the size of the spot imaged by the optical assembly at the target. In other words, the smaller the imaged spot of light at the target, the better the position of the target can be determined in three dimensions. So the performance illustrated in Figure 5 shows that the typical performance achieved using the type of system described in this document can be diffraction limited, as will be clear to those in the art.

[0043] In addition, the size of the imaged spot determines how much light can be collected by the optical assembly. If more light is focused onto the target, more light is reflected or scattered by the target and an appropriate fraction of that reflected or scattered light is collected by the optical assembly and focused back to the fiber 116, allowing an accurate measurement of the distance between the laser radar and the target. In other words, a smaller spot allows more measurement light to return to the optical assembly and a more accurate distance measurement to be made, using the techniques described by US patents 4,733,609, 4,824,251, 4,830,486, 4,969,736, 5,114,226, 7,139,446, 7,925,134, and Japanese Patent #2,664,399.

[0044] Figure 6 shows an example of the focus location of the measurement and pointing beams as a function of the axial position of the moving group 136, with such an optical assembly. The plot shown in Figure 6 shows the moving group position specifically for the configuration shown in Figures 3B and 3C, and demonstrates that to go from 1 meter to 60 meters in distance (from the laser radar housing 112 to the target) requires approximately 47 mm of movement of the moveable group of optics 136.

[0045] As will be appreciated by those in the art, the optical assembly 114 is compact and rigid, and uses the concave mirror 130 for much of the optical power. Also, the concave mirror 130 produces no chromatic aberration. In Figures 3A-3C, the window 122 has the small silvered region 126 added to one side of the window (creating a small obscuration). The other side of the window 122, would have a wavelength selective coating that transmits light in the predetermined (e.g. visible red, 1R) wavelength ranges, and reflects light in the visible part of the spectrum, except for the wavelength used for the visible pointing beam. This allows the camera 140 to use that remaining visible light to view the scene being measured by the laser radar system.

[0046] Also, it should be noted that the primary mirror 130 is concave, and preferably, it is spherical. The primary mirror 130 can help achromatize the optical assembly. Focusing can be accomplished by the bi concave or plano concave moving lens 132 in the embodiment of Figure 3(A). Focusing can also be accomplished by moving the lens group 136 (Figures 3B, 3C) between the primary mirror 130 and the cold mirror 122.

[0047] Thus, the catadioptric optical assembly, provides a compact optical assembly, designed to (i) remove the need for a moving mirror (removing problematic doppler effects), (ii) get the two wavelengths (red and IR) in focus simultaneously. The moveable lens 132, or lens group 136, located between the concave mirror 130 and the window (or cold mirror) 122 achieve focusing, with the components described and shown herein.

[0048] Moreover, the optical assembly is designed to provide a continuous focus range from 1 meter to 60 meters, from the window (or cold mirror) 122. The obscuration on the back surface of the window (or cold mirror) is quite small, and the chromatic aberration introduced by the relay 124 is corrected by the catadioptric optics.

[0049] Thus, optical assembly a compact optical assembly that is useful in a laser radar system because it eliminates the need for a large scanning (pointing) mirror that is moveable relative to other parts of the laser radar system. In addition, the compact optical assembly has a catadioptric configuration with a concave mirror that provides most of the optical power, and allows easier achromatization between the two required wavelengths of the pointing and measurement beams. The concave mirror folds the optical path onto itself, reducing the overall size substantially. The size of the system should be small enough to allow the camera 140 (Figures 2, 3A) to be located on the moving part of the laser radar system, eliminating parallax effects by use of a reflective window or cold mirror that allows the camera optical axis to be collinear with the axis of the measurement beam. Since the window (or cold mirror) 122 is the last optical element before the light is projected to the target, this new optical assembly allows a wide field-of-view camera 140 to be used that can point in the same direction and along the same axis as the laser radar by configuring the camera's view to be reflected off of the window (or cold mirror) 122. The obscuration is small and won't cause significant increases in the size of the spot produced at the target during laser radar operation.

[0050] Accordingly, the foregoing description, provides a compact optical assembly for a laser radar system, comprising catadioptric optics that moves as a unit with the laser radar system and transmits pointing and measurement beams to the outlet of the laser radar system, while eliminating the need for a scanning (pointing) mirror that is moveable relative to other components of the laser radar system. With the foregoing description in mind, the manner in which the optical assembly can be implemented in various types of laser radar systems will be apparent to those in the art.

Second Configuration

[0051] The following disclosure relates to a second configuration of the laser radar system 100 that is configured and operates in accordance with the general principles described above in connection with Figures 1 and 2. Certain basic features of an optical assembly 114 can be appreciated from Figures 7a and 7b. The optical assembly of Figure 7a comprises a light source represented by a fiber 116 through which a pointing beam and a measurement beam are directed, a lens 142, a scanning reflector 144 and a fixed reflector that in Figure 7a comprises a plane mirror 146. Those components co-operate to direct and focus the pointing and measurement beams from the fiber 116 along a line of sight 148 that preferably coincides with the optical axis of the optical assembly and extends through the lens 142. The fiber 116, the lens 142, the scanning reflector 144a and the plane mirror are oriented relative to each other such that the pointing and measurement beams from the fiber 116 are reflected by the scanning reflector 144a to the plane mirror 146, and reflected pointing and measurement beams from the plane mirror 146 are reflected again by the scanning reflector 144a and directed along the line of sight 148 through the lens 142. The pointing and measurement beams are then directed from the laser radar system and at the target 106.

[0052] In Figure 7a, the scanning reflector 144a comprises a retroreflector that is preferably a corner cube that translates (e.g. in the z direction) relative to the fiber 116, the lens 142 and the plane mirror 146 which are all fixed to the support structure of the optical assembly. Movement (or translation) of the corner cube 144a adjusts the focus of the pointing and measurement beams along the line of sight 148 by the changing the distance the measurement beam travels between the fiber and the lens. The corner cube 144a has at least three reflective surfaces that are oriented so that (i) the pointing and measurement beams from the source are reflected through the corner cube 134 to the plane mirror 146, (ii) the pointing and measurement beams reflected from the plane mirror 146 are again reflected through the corner cube 144a, and (iii) movement of the corner cube in at least one predetermined direction (e.g. the z direction in Figure 7a) adjusts the focus of the pointing and measurement beams along the line of sight 148, in a manner that is substantially unaffected by movement of the corner cube in directions transverse to the predetermined direction or by rotations of the corner cube relative to the predetermined direction. Figure 7b is a fragmentary, schematic illustration of the optical assembly of Figure 7a, showing the reflection schema provided by the corner cube 144a and the plane mirror 146, that makes the reflection of the pointing and measurement beams unaffected by movement of the corner cube 144a in directions transverse to the z direction or by rotation of the corner cube relative to the z direction.

[0053] The fiber 116 is associated with a fiber beam combiner that combines a pointing beam in the visible (e.g. red) wavelength range with the measurement beam in the different, e.g. infrared (IR) wavelength range. The pointing beam and measurement beams are generated from separate sources, and are combined by the fiber beam combiner (that is located inside the base 110) in a manner well known to those in the art. The combined pointing and measurement beams are directed from the fiber 116 and focused along the line of sight 148 in the manner described herein.

[0054] Thus, with the version shown in Figure 7a and 7b, the pointing and measurement beams are directed along the line of sight 148, and the focus of the pointing and measurement beams along the line of sight is adjusted by translation of a single element (i.e. the corner cube 144a) and in a way that is insensitive to (i.e. unaffected by) movement of the corner cube in directions transverse to the z direction or by rotation of the corner cube relative to the z direction. Also, the optical assembly of Figures 7a and 7b is extremely compact, and made up of relatively few elements. For a given configuration, the corner cube 144a can adjust the focus of the pointing and measurement beams by translation over a distance of not more than about 22 mm relative to the fixed components (fiber, plane mirror and lens), which contributes to the compactness of the optical assembly.

[0055] With the version of figure 7a and 7b, the pointing and measurement beams are directed along the line of sight and to the outlet 120 of the laser radar system. The pointing and measurement beams direct the measurement beam from the laser radar system and to a spot on the target 106, where the radiation is reflected and/or scattered by the target. In accordance with the principles of a laser radar system, the optical assembly 114 will receive at least some radiation that is reflected or scattered from the target 106, and that radiation will be directed back through the fiber 116, in a manner that will be apparent to those in the art.

[0056] The size of the imaged spot of the measurement beam on the target 106 determines how much light can be collected by the optical assembly. If more light is focused onto the target, more light is reflected or scattered by the target and an appropriate fraction of that reflected or scattered light is collected by the optical assembly and focused back to the fiber 116, allowing an accurate measurement of the distance between the laser radar and the target. In other words, a smaller spot allows more measurement light to return to the optical assembly and a more accurate distance measurement to be made, using the techniques described by US patents 4,733,609, 4,824,251, 4,830,486, 4,969,736, 5,114,226, 7, 139,446, 7,925,134, and Japanese Patent #2,664,399.

[0057] In the optical assembly shown in Figures 7a and 7b, the provision of the plane mirror 146 which is fixed in relation to the corner cube 144a sends the first pass beam that leaves the corner cube back through the corner cube, while the system remains insensitive to tip/tilt of the translating corner cube relative to the z direction. The lateral translation of the corner cube 144a in the z direction still causes a shift on the first pass, but the plane mirror 146 reverses the beam back through the corner cube, where it picks up an equal and opposite shift, cancelling it out. On each pass through the corner cube, the retroreflective properties of the corner cube insure that the output beam is parallel to the input beam, regardless of the orientation of the corner cube, i.e. tip, tilt or roll. Thus, the system in Figure 7a is therefore nominally insensitive to tip/tilt and x/y motions of the corner cube. Figure 7b shows how the fixed plane mirror 146 makes the system insensitive to x/y motions of the corner cube

[0058] In addition, since the laser radar system uses two wavelengths, and the system is sensitive to back reflections, the corner cube 144a could also be a set of three mirrors an air-corner cube), rather than a solid glass traditional corner cube. Then, each beam is incident on a first surface mirror. Therefore, there are no surfaces that can create a ghost image that can contribute the noise floor for the distance measuring component of the laser radar, other than the 2" lens for providing the optical power.

[0059] Since the corner cube 144a is traversed by the beam twice and is reflected, the optical path between the fiber 116, and the lens 142 is four times the motion of the corner cube; a 1 mm motion of the corner cube changes the distance between the fiber and lens by 4 mm. Based on the known NA of the fiber of about 0.1, it can be seen that the ideal focal length for the fixed lens 142 is about 250 mm, based on an output aperture of 50 mm. Based on the Newtonian equations for object/image relationships, the total focus range required is about 88 mm between the near (1 meter) and far (60 meter) focus positions. This translates to a comer cube translation of 88/4 = ~22 mm Therefore, the only lens required is the 2" diameter objective lens 142.

[0060] The other big advantage of this optical assembly is that because the optical path 148 is folded through the corner cube 144a twice, the 250 mm to (88+250)= 338 mm is fit into a very compact volume. The long focal length means the aberration requirements on the lens 142 are also relaxed relative to a shorter, unfolded system.

[0061] A major difference between this system and the systems where a transmissive optic(s) is (are) translated is that since the fiber is the z position reference, motion of the focusing element (the comer cube 144a) changes the z position between the fiber 116 and the last lens element. Therefore, the system must know the position of the corner cube accurately enough to make a simple correction for this motion. A current system parameter has an axial position measurement accuracy of 5 µm + 1.25ppm/meter, or a minimum of 6.25 µm at 1 meter focus. This means the stage position must be measured to 6.25/4 = 1.56 µm, worst case. At far focus (60 m), the stage must only be known to 80/4 = 20 µm. Given all the advantages of this system, this seems to be a small tradeoff.

[0062] With the system of Figure 7a, the input fiber 116 is right in the middle of the diverging output beam. If the system was built like figure 7a, the structure for holding the fiber 116 would block light, and some of the light would be incident directly back on the fiber, potentially introducing a noise floor. The alternative system shown in Figures 8a, 8b and 8c provides a way of addressing this issue.

[0063] The optical assembly 14a that is shown in Figures 8a, 8b and 8c includes a fiber 116a that provides a source of the pointing and measurement beams, a lens 142a, a scanning reflector 144a and a fixed reflector 146a. The scanning reflector 144a comprises a reflective roof that provides two reflections of the pointing and measurement beams, and the fixed reflector 146a comprises a reflective roof that also provides two reflections of the pointing and measurement beams. Also, the nodal lines 145, 147 of the reflective roofs 144a and 145, respectively, are in a predetermined orientation relative to each other.

[0064] The version shown in Figures 8a, 8b and 8c, functions in a manner that is generally similar to that of the version of Figures 7a and 7b. The reflective roof 144a has a pair of reflective surfaces that are oriented so that (i) the pointing and measurement beams from the source are reflected through the reflective roof 144a to the fixed reflective roof 146a, and the pointing and measurement beams reflected from the fixed reflective roof 146a are again reflected through the reflective roof 144a, and (ii) movement of the reflective roof 144a in at least one predetermined direction (e.g. the z direction in Figure 8a) adjusts the focus of the pointing and measurement beams along the line of sight 148a Figure 8c is a fragmentary, schematic illustration of the optical assembly of Figures 8a and 8b, showing the reflection schema provided by the reflective roof 144a and the fixed reflective roof 146a. Thus, the pointing and measurement beams are directed along the line of sight 148a, and the focus of the pointing and measurement beams along the line of sight is adjusted by translation of a single element (the reflective roof 144a) in the z direction relative to the fixed reflective roof 146a, the lens 142a, and the fiber 116a. The optical assembly of Figures 8a, 8b and 8c is extremely compact, and made up of relatively few elements. As with the previous version, the reflective roof 144a can adjust the focus of the pointing and measurement beams by translation over a distance of not more than 22 mm relative to the fixed components (fiber 116a, fixed reflective roof 144a and lens 142a), which contributes to the compactness of the optical assembly 114a.

[0065] The optical assembly of Figures 8a, 8b and 8c addresses the issue of the input fiber being right in the middle of the diverging output beam, so that the structure for holding the fiber would block light, and some of the light would be incident directly back on the fiber, causing a large noise floor. Specifically, instead of translating a corner cube and using a fixed mirror, the optical assembly is broken into the two reflective roofs 144a, 146a. The reflective roof 144a translates in place of the comer cube, and reflective roof 146a is fixed and rotated 90° about the optical axis relative to the translating reflective roof 144a. This optical assembly achieves the same advantages as the system in figure 7a with one major additional advantage and one disadvantage. The pointing and measurement beams from the input fiber 116 go to the moving reflective roof 144a, and are translated down by reflective roof 144a. The pointing and measurement beams then go to the fixed reflective roof 146a, which shifts those beams into the page. Then the beams go back through reflective roof 144a and come out expanded but parallel to the input fiber 116a. However, thanks to the fixed roof 144a, the beams are translated relative to the fiber 116a in the -y direction of Figures 8a and 8b. Therefore, there is no obscuration or back reflection issue. The disadvantage, however, is that if the translating roof rotates about the z-axis, these ideal characteristics no longer hold exactly true.

[0066] If reflective roof 144a rotates about y while translating, it acts like a roof and doesn't change the angle. If it rotates about x, then reflective roof 144a acts like a plane mirror but fixed reflective roof 146a removes this angle change because fixed reflective roof 146a is rotated about the z-axis by 90 degrees. If reflective roof 144a shifts in x, it does shift the beam, but then fixed reflective roof 146a acts like a mirror (as in the system of figure 7a) and the second pass through reflective roof 144a corrects the shift. Finally, if reflective roof 144a shifts in y, it is like a plane mirror, so there is no change for the beam.

[0067] A series of first surface mirrors (in the form of two roof prisms forming the reflective roofs 144a, 146a) is used to change the axial distance between the fiber 116a and the fixed lens 142a. This system is nominally insensitive to tip/tilt and x/y shift of the moving element (the reflective roof 144a). The output beam from the two roof system is shifted relative to the input fiber 116a, so there is no obscuration or back reflection issue. In addition, since all the surfaces are first surface mirrors, there are no interfaces that can create ghost reflections. The folded nature of the beam path makes it very compact, allowing for stable mechanics. The long focal length of the system means the fixed reflective roof 146a can likely be an off-the-shelf color corrected doublet.

[0068] Figures 9-13 schematically illustrate various concepts for configuring and orienting the components of the optical assembly of the second configuration, which relate to embodiments of the claimed invention.

[0069] For example, as shown in Figure 9, the pointing and measurement beams reflected by the scanning reflector 144 and directed along the line of sight 138 through the lens, are reflected by a fold mirror 140 that folds the line of sight 138 of the pointing and measurement beams directed through the lens 142. As further shown in Figure 9, the fiber 116 can be located in the fold mirror 140.

[0070] The optical assembly is designed to be focused at a range of a meter to 60 meters from the lens 132. When the system shown in Figure 9 is focused at 1 meter from the lens, less light is directed to the target, but the light loss is only a few percent. When the optical assembly is focused at 60 meters, by movement of the corner cube 144 about 22 mm, the beam pretty much fills the aperture of the lens 142, so substantially all the light is used to make the spot that impinges on the target.

[0071] In addition, as schematically shown in Figure 10, the lens 142, the beam source (i.e. fiber 116) and the plane mirror 146 are supported in a manner such that they can move as a unit relative to the retroreflector 144, and wherein the line of sight moves with the unit. Thus, as illustrated by Figure 6, the lens 142, the plane mirror and the fiber 116 are supported by a box 146B, so that all of those components can move as a unit relative to the retroreflector 144. Therefore, reference to the retroreflector and the other components (fiber, lens, fixed reflector) being moveable "relative" to each other can mean that the other components are fixed by a support structure, and the retroreflector moves relative to the support structure, or the support structure for the other components (e.g. the box 146B in Figure 6) enables those other components to move (e.g. rotate) as a unit relative to the retroreflector 144.

[0072] Moreover, as also shown in Figure 10, the pointing and measurement beams reflected by the scanning reflector 144 and directed along the line of sight through the lens 142 are reflected by a polarization beam splitter plate 150 that folds the line of sight 148 of the pointing and measurement beams directed through the lens (in a manner similar to that shown in Figure 9). In Figure 10, the polarization beam splitter plate 150 has a polarization beam splitting coating that enables the polarization beam splitter plate 150 to function as a polarization beam splitter, and a quarter wave plate 151 is provided on the plane mirror 146, to adjust the polarization of the beams reflected from the plane mirror 146. In Figure 6, the optical fiber 116 that is the beam source is represented by a dot in a predetermined location relative to the polarization beam splitter plate 150.

[0073] Thus, in the concept shown in Figure 10, the polarization beam splitter plate (PBS) 150 is used to prevent the light being directed along the line of sight from coupling back into the fiber 116. Since the measurement beam is linearly polarized, its polarization state can be rotated 90 degrees by going through the quarter wave plate (QWP) 151 oriented at 45 degrees twice. In this case, the QWP 151 also has the second surface mirror 146 that acts as the mirror 146 of the system in the manner shown and described in connection with Figure 7a. The fiber 116 is placed near the back surface of the PBS plate 150. Since it is a PBS plate and the input surface is tilted at 45 degrees relative to the fiber, any reflection off the back surface will not go back to the fiber. The corner cube 144 is solid glass, since this is an off-the-shelf part and since this increases the axial distance (physical distance) between the fiber and the lens. There is no obscuration in this optical assembly.

[0074] Also, in the concept shown in Figure 10, the corner cube 144 can be held fixed and the plane mirror, fold mirror, lens and fiber (all of which are supported in the box 146B) all rotate about the centerline of the corner cube. The rotation must be about the centerline of the corner cube or else the beams will move outside the edges of the comer cube during rotation. This concept of the second embodiment, can reduce the rotating mass that needs to be moved about an elevation axis, which would allow a smaller, lighter elevation axis motor to be used and would also result in less heat generation (the heat source being the actuator used to move the components). Also, it may result in an even more compact assembly. It can also lead to a reduction in focus stage complexity, and result in fewer cables that need to pass through a rotating joint so cable routing is simpler and cable disturbances caused by moving cables can be reduced to improve motion accuracy and thus instrument performance. Thus, this aspect of the concept of Figure 10 can produce a smaller, simpler and more cost effective optical assembly, and reduction of cable disturbances should also improve accuracy.

[0075] Still further, as shown schematically in Figure 11, the source comprises an optical fiber 116 supported by a monolithic member 152 that has a portion 136b that functions as the plane mirror and another portion 154 that folds the line of sight 148 of the pointing and measurement beams reflected by the scanning reflector 144 and directed along the line of sight through the lens 142.

[0076] Also, as shown schematically in Figure 12, the source can comprise an optical fiber 116 supported by a transmissive member (e.g. a glass window 160) that has a reflective portion 136c thereon that forms the plane mirror. In addition, the optical fiber can be supported by a mechanical structure 162 that applicants refer to as a "spider", shown in Figure 13, that includes a series of struts 164 with a central opening 166 that forms the support for the optical fiber. The spider 162 can be made of a lightweight metal such as aluminum. Thus, the optical assembly can comprise the glass plate 160 with a hole for the fiber and a silvered area as the mirror 136c (as shown in Figure 12) or a metal plate with the spider (Figure 13) to hold the fiber and let light through and a separate mirror surface machined and polished that is attached to the spider, and forms the reflective portion 136c. Therefore, Figures 12 and 13 are similar, except that in Figure 12 the transmissive member 160 that supports the fiber is a piece of glass, and in Figure 13 the transmissive member is the air space(s) between the mechanical components of the spider 162.

[0077] The concepts shown in Figures 11, 12 and 13 provide additional advantageous features to the optical assembly. For example, the concept of Figure 1 1 uses a single substrate for both mirrors and for holding the fiber. This may provide simpler fabrication, and may allow the single substrate to be formed of relatively light weight aluminum. With respect to the concepts of Figures 12 and 13, replacing a fold mirror with the window or window/spider arrangement, can reduce the overall weight of the optical assembly, because it eliminates the weight of a fold mirror. Also, the concepts of Figures 12 and 13 can reduce the requirement for additional tolerances on surface figure and mirror angle position. The result is that the corner cube now moves parallel to the optical axis of the lens rather than perpendicular to it. Thus, the optical assembly is simplified because it has one less mirror, so the angle between the mirrors is one less specification to meet. Moreover, the angle between the fiber hole and the mirror surface is more directly controllable when cutting normal to the surface (not really a problem if we use the monolithic metal mirror concept of Figure 11). Also, the position of the fiber axis relative to the lens can be maintained more easily during fabrication (e.g. by holding both elements in a tube), thereby reducing the out-of-focus (repeatable) boresight error that occurs because the beam is not centered in the aperture. Still further because the fiber hole is parallel to the optical axis of the lens, it should also be easier to align the two, and strongly reduce thermal boresight error. Additionally, the corner cube can be closer to the fiber, so it can be smaller.

[0078] Accordingly, as seen from the foregoing description, the optical assembly provides a compact optical assembly for a laser radar system, comprising a light source, a lens, a scanning reflector and a fixed reflector that co-operate to focus a beam from the light source along a line of sight that extends through the lens, where the light source, the lens, the scanning reflector and the fixed reflector are oriented relative to each other such that (i) a beam from the light source is reflected by the scanning reflector to the fixed reflector, (ii) reflected light from the fixed reflector is reflected again by the scanning reflector and directed along the line of sight through the lens, and (iii) the scanning reflector is moveable relative to the source, the lens and the fixed reflector, to adjust the focus of the beam along the line of sight.

[0079] In the disclosed configurations, laser radar system 100 has the pointing beam and measurement beam. However, the laser radar system 100 may have the measurement beam without the pointing beam. For example, the measurement beam is in the visible. Therefore, in this case, the measurement beam can also play pointing beam. The laser radar system 100 of this embodiment has the different wavelength region between the pointing beam and measurement beam. However, the laser radar system 100 may have the same wavelength region such as the visible region.

[0080] In embodiments of the invention, the optical assembly has a lens, a scanning reflector and a fixed reflector. However, in other configurations not forming part of the claimed invention, the optical assembly may have a lens, a scanning reflector without a fixed reflector. For example, the measurement beam can be directly directed from reflector to lens.

[0081] As for the laser radar system 100, the second configuration is also applicable to the distance measurement system that determine six degrees of freedom (α, β, d, ϕ, X, ψ) of a reflector or of an object on which the reflector is arranged, comprises an angle-and distance measurement apparatus, e.g. a laser tracker as disclosed in US published application US2006-0222314. As for the laser radar system 100, the present disclosure is also applicable to the distance measurement system that determine a distance between the measurement system and the target point and/or a change of this distance by comparison of the emitted and reflected laser light, e.g. a laser tracker as disclosed in US published application US 2011-0181872.

[0082] Next, explanations will be made with respect to a structure manufacturing system provided with the measuring apparatus (laser radar system 100) described hereinabove.

[0083] Fig. 14 is a block diagram of a structure manufacturing system 700. The structure manufacturing system is for producing at least a structure from at least one material such as a ship, airplane and so on, and inspecting the structure by the profile measuring apparatus 100. The structure manufacturing system 700 of the embodiment includes the profile measuring apparatus 100 as described hereinabove in the embodiment, a designing apparatus 610, a shaping apparatus 620, a controller 630 (inspection apparatus), and a repairing apparatus 640. The controller 630 includes a coordinate storage section 631 and an inspection section 632.

[0084] The designing apparatus 610 creates design information with respect to the shape of a structure and sends the created design information to the shaping apparatus 620. Further, the designing apparatus 610 causes the coordinate storage section 631 of the controller 630 to store the created design information. The design information includes information indicating the coordinates of each position of the structure.

[0085] The shaping apparatus 620 produces the structure based on the design information inputted from the designing apparatus 610. The shaping process by the shaping apparatus 620 includes such as casting, forging, cutting, and the like. The profile measuring apparatus 100 measures the coordinates of the produced structure (measuring object) and sends the information indicating the measured coordinates (shape information) to the controller 630.

[0086] The coordinate storage section 631 of the controller 630 stores the design information. The inspection section 632 of the controller 630 reads out the design information from the coordinate storage section 631. The inspection section 632 compares the information indicating the coordinates (shape information) received from the profile measuring apparatus 100 with the design information read out from the coordinate storage section 631. Based on the comparison result, the inspection section 632 determines whether or not the structure is shaped in accordance with the design information. In other words, the inspection section 632 determines whether or not the produced structure is non-defective. When the structure is not shaped in accordance with the design information, then the inspection section 632 determines whether or not the structure is repairable. If repairable, then the inspection section 632 calculates the defective portions and repairing amount based on the comparison result, and sends the information indicating the defective portions and the information indicating the repairing amount to the repairing apparatus 640.

[0087] The repairing apparatus 640 performs processing of the defective portions of the structure based on the information indicating the defective portions and the information indicating the repairing amount received from the controller 630.

[0088] Fig. 15 is a flowchart showing a processing flow of the structure manufacturing system 700. With respect to the structure manufacturing system 700, first, the designing apparatus 610 creates design information with respect to the shape of a structure (step S101). Next, the shaping apparatus 620 produces the structure based on the design information (step S102). Then, the profile measuring apparatus 100 measures the produced structure to obtain the shape information thereof (step S103). Then, the inspection section 632 of the controller 630 inspects whether or not the structure is produced truly in accordance with the design information by comparing the shape information obtained from the profile measuring apparatus 100 with the design information (step S104).

[0089] Then, the inspection portion 632 of the controller 630 determines whether or not the produced structure is non-defective (step S105). When the inspection section 632 has determined the produced structure to be non-defective ("YES" at step S105), then the structure manufacturing system 700 ends the process. On the other hand, when the inspection section 632 has determined the produced structure to be defective ("NO" at step S105), then it determines whether or not the produced structure is repairable (step S106).

[0090] When the inspection portion 632 has determined the produced structure to be repairable ("YES" at step S106), then the repair apparatus 640 carries out a reprocessing process on the structure (step S107), and the structure manufacturing system 700 returns the process to step S103. When the inspection portion 632 has determined the produced structure to be unrepairable ("NO" at step S106), then the structure manufacturing system 700 ends the process. With that, the structure manufacturing system 700 finishes the whole process shown by the flowchart of Fig. 15.

[0091] With respect to the structure manufacturing system 700, because the profile measuring apparatus 100 can correctly measure the coordinates of the structure, it is possible to determine whether or not the produced structure is non-defective. Further, when the structure is defective, the structure manufacturing system 700 can carry out a reprocessing process on the structure to repair the same.

[0092] Further, the repairing process carried out by the repairing apparatus 640 may be replaced such as to let the shaping apparatus 620 carry out the shaping process over again. In such a case, when the inspection section 632 of the controller 630 has determined the structure to be repairable, then the shaping apparatus 620 carries out the shaping process (forging, cutting, and the like) over again. In particular for example, the shaping apparatus 620 carries out a cutting process on the portions of the structure which should have undergone cutting but have not. By virtue of this, it becomes possible for the structure manufacturing system 700 to produce the structure correctly.

[0093] In the above, the structure manufacturing system 700 includes the profile measuring apparatus 100, the designing apparatus 610, the shaping apparatus 620, the controller 630 (inspection apparatus), and the repairing apparatus 640. However, present teaching is not limited to this configuration. For example, a structure manufacturing system in accordance with the present teaching may include at least the shaping apparatus and the profile measuring apparatus.

[0094] Thus, the present disclosure provides new and useful concepts for an apparatus, optical assembly, method for inspection or measurement of an object and method for manufacturing a structure. With the foregoing description in mind, the manner in which those concepts (e.g. the optical assembly of the present embodiments) can be implemented in various types of laser radar systems, as well as other types of optical systems and methods, will be apparent to those in the art.

Claims

1. Laser radar apparatus for inspecting or measuring an object comprising an optical assembly moveable as a unit as part of the apparatus, the optical assembly comprising:

a light source comprising an optical fiber (116),

characterised in that:

the optical assembly includes a fixed reflector (146), a scanning reflector (144) and a lens (142);

the optical assembly is configured to direct a measurement beam from the light source along a line of sight and through an outlet of the optical assembly;

the fiber, the lens, the scanning reflector and the fixed reflector are oriented relative to each other such that the measurement beam from the fiber is reflected by the scanning reflector to the fixed reflector and the reflected measurement beam from the fixed reflector is reflected again by the scanning reflector before being directed along the line of sight through the lens;

the scanning reflector is moveable relative to the fixed reflector to adjust the focus of the measurement beam along the line of sight, the fixed reflector being configured to fold the optical path of the measurement beam; and

the optical fiber is located in an optical path of the folded measurement beam between the scanning reflector and the outlet, wherein:

the optical fiber is supported by a transmissive member (160); or

the optical fiber is supported by a mechanical structure (164) including a series of struts (164) having a central opening (166) for supporting the optical fiber; or

the optical fiber is supported by a monolithic member (152) that has the fixed reflector and another portion (154) that folds the line of sight of the measurement beam reflected by the scanning reflector.

2. The apparatus of claim 1, further comprising a moveable portion configured to move the optical assembly along two axes that have different directions.

3. The apparatus of claim 2, wherein the scanning reflector comprises a retroreflector, and the fixed reflector comprises a plane mirror.

4. The apparatus of claim 3, wherein the retroreflector comprises a corner cube that has at least three reflective surfaces that are oriented so that (i) the measurement beam from the light source is reflected through the corner cube to the plane mirror, and the measurement beam reflected from the plane mirror is again reflected through the corner cube, and (ii) movement of the corner cube in at least one predetermined direction adjusts the focus of the measurement beams along the line of sight, in a manner that is substantially unaffected by movement of the corner cube in directions transverse to the predetermined direction or by rotations of the corner cube relative to the predetermined direction.

5. The apparatus of any preceding claim, further comprising a motor for moving the optical assembly and an encoder for monitoring the position of the optical assembly.

6. The apparatus of any preceding claim, wherein the optical assembly is moveable about two different axes.

7. The apparatus of any preceding claim, wherein the apparatus is arranged to direct a pointing beam, having a wavelength which is in a visible wavelength range and which is different from a wavelength of the measurement beam, along the optical path of the measurement beam towards the object.

8. The apparatus of any preceding claim, further comprising a photo detector arranged such that a distance from the object is obtainable based on the received measurement beam from the object.

9. A method for manufacturing a structure, comprising:

producing the structure based on design information;

obtaining shape information of structure by using of the apparatus of at least one of claims 1 to 8;

comparing the obtained shape information with the design information.

10. The method for manufacturing the structure according to claim 9 further comprising reprocessing the structure based on the comparison result.

11. The method for manufacturing the structure according to claim 10, wherein reprocessing the structure includes producing the structure over again.

Ansprüche

1. Laserradarvorrichtung zum Untersuchen oder Vermessen eines Objekts, umfassend eine optische Anordnung, die als Einheit als Teil der Vorrichtung bewegbar ist, wobei die optische Anordnung umfasst:
eine Lichtquelle, die eine optische Faser (116) umfasst, dadurch gekennzeichnet, dass:

die optische Anordnung einen feststehenden Reflektor (146), einen Abtastreflektor (144) und eine Linse (142) beinhaltet;

die optische Anordnung dazu ausgestaltet ist, einen Messstrahl von der Lichtquelle entlang einer Sichtlinie und durch einen Ausgang der optischen Anordnung zu richten;

die Faser, die Linse, der Abtastreflektor und der feststehende Reflektor relativ zueinander so ausgerichtet sind, dass der Messstrahl von der Faser durch den Abtastreflektor zum feststehenden Reflektor reflektiert wird und der reflektierte Messstrahl von dem feststehenden Reflektor wiederum durch den Abtastreflektor reflektiert wird, bevor er entlang einer Sichtlinie durch die Linse gerichtet wird;

der Abtastreflektor relativ zum feststehenden Reflektor bewegbar ist, um den Fokus des Messstrahls entlang der Sichtlinie einzustellen, wobei der feststehende Reflektor dazu ausgestaltet ist, den optischen Pfad des Messstrahls zu falten; und

die optische Faser in einem optischen Pfad des gefalteten Messstrahls zwischen dem Abtastreflektor und dem Ausgang angeordnet ist, wobei:

die optische Faser durch ein durchlässiges Element (160) gestützt ist; oder

die optische Faser durch eine mechanische Struktur (164) gestützt ist, die eine Reihe von Streben (164) beinhaltet, die eine mittige Öffnung (166) zum Stützen der optischen Faser aufweisen; oder

die optische Faser durch ein monolithisches Element (152) gestützt ist, das den feststehenden Reflektor und einen anderen Abschnitt (154) aufweist, der die Sichtlinie des Messstrahls faltet, der durch den Abtastreflektor reflektiert wird.

2. Vorrichtung nach Anspruch 1, ferner umfassend einen bewegbaren Abschnitt, der dazu ausgestaltet ist, die optische Anordnung entlang zweier Achsen, die unterschiedliche Richtungen aufweisen, zu bewegen.

3. Vorrichtung nach Anspruch 2, bei der der Abtastreflektor einen Retroreflektor umfasst und der feststehende Reflektor einen ebenen Spiegel umfasst.

4. Vorrichtung nach Anspruch 3, wobei der Retroreflektor einen Eckwürfel umfasst, der zumindest drei reflektierende Oberflächen aufweist, die so ausgerichtet sind, dass (i) der Messstrahl von der Lichtquelle durch den Eckwürfel zu dem ebenen Spiegel reflektiert wird, und der Messstrahl, der von dem ebenen Spiegel reflektiert wird, wiederum durch den Eckwürfel reflektiert wird, und (ii) eine Bewegung des Eckwürfels in zumindest eine vorbestimmte Richtung den Fokus des Messstrahls entlang der Sichtlinie in einer Weise einstellt, die im Wesentlichen unbeeinträchtigt durch eine Bewegung des Eckwürfels in Richtungen quer zu der vorbestimmten Richtung oder durch Rotationen des Eckwürfels relativ zu der vorbestimmten Richtung ist.

5. Vorrichtung nach einem der vorhergehenden Ansprüche, ferner umfassend einen Motor zum Bewegen der optischen Anordnung und einen Encoder zum Beobachten der Position der optischen Anordnung.

6. Vorrichtung nach einem der vorhergehenden Ansprüche, bei der die optische Anordnung um zwei unterschiedliche Achsen bewegbar ist.

7. Vorrichtung nach einem der vorhergehenden Ansprüche, wobei die Vorrichtung angeordnet ist, um einen Richtstrahl, der eine Wellenlänge aufweist, die innerhalb eines sichtbaren Wellenlängenbereichs liegt und die sich von einer Wellenlänge des Messstrahls unterscheidet, entlang des optischen Pfads des Messstrahls auf das Objekt zu richten.

8. Vorrichtung nach einem der vorhergehenden Ansprüche, ferner umfassend einen Photodetektor, der so angeordnet ist, dass eine Distanz von dem Objekt auf Grundlage des von dem Objekt empfangenen Messstrahls erhaltbar ist.

9. Verfahren zum Fertigen einer Struktur, das umfasst:

Herstellen der Struktur auf Grundlage von Gestaltungsinformationen;

Erhalten von Forminformationen der Struktur durch Verwenden der Vorrichtung zumindest eines der Ansprüche 1 bis 8;

Vergleichen der erhaltenen Forminformationen mit den Gestaltungsinformationen.

10. Verfahren zum Fertigen der Struktur nach Anspruch 9, ferner umfassend ein Wiederbearbeiten der Struktur auf Grundlage des Vergleichsergebnisses.

11. Verfahren zum Fertigen der Struktur nach Anspruch 10, wobei das Wiederbearbeiten der Struktur das erneute Herstellen der Struktur beinhaltet.

Revendications

1. Appareil radar laser servant à inspecter ou mesurer un objet comprenant un ensemble optique mobile comme une unité comme partie de l'appareil, l'ensemble optique comprenant :

une source de lumière comprenant une fibre optique (116),

caractérisé en ce que :

l'ensemble optique inclut un réflecteur fixe (146), un réflecteur de balayage (144) et une lentille (142) ;

l'ensemble optique est configuré pour diriger un faisceau de mesure depuis la source de lumière le long d'une ligne de visée et à travers une sortie de l'ensemble optique ;

la fibre, la lentille, le réflecteur de balayage et le réflecteur fixe sont orientés les uns par rapport aux autres de sorte que le faisceau de mesure depuis la fibre soit réfléchi par le réflecteur de balayage au réflecteur fixe et le faisceau de mesure réfléchi du réflecteur fixe soit réfléchi de nouveau par le réflecteur de balayage avant d'être dirigé le long de la ligne de visée à travers la lentille ;

le réflecteur de balayage est mobile par rapport au réflecteur fixe pour ajuster la focalisation du faisceau de mesure le long de la ligne de visée, le réflecteur fixe étant configuré pour plier le trajet optique du faisceau de mesure ; et

la fibre optique est située dans un trajet optique du faisceau de mesure plié entre le réflecteur de balayage et la sortie, dans lequel :

la fibre optique est supportée par un élément de transmission (160) ; ou

la fibre optique est supportée par une structure mécanique (164) incluant une série d'entretoises (164) présentant une ouverture centrale (166) pour supporter la fibre optique ; ou

la fibre optique est supportée par un élément monolithique (152) qui présente le réflecteur fixe et une autre partie (154) qui plie la ligne de visée du faisceau de mesure réfléchi par le réflecteur de balayage.

2. Appareil selon la revendication 1, comprenant en outre une partie mobile configurée pour déplacer l'ensemble optique le long de deux axes qui présentent différentes directions.

3. Appareil selon la revendication 2, dans lequel le réflecteur de balayage comprend un rétroréflecteur, et le réflecteur fixe comprend un miroir plan.

4. Appareil selon la revendication 3, dans lequel le rétroréflecteur comprend un cube de coin qui présente au moins trois surfaces réfléchissantes qui sont orientées de sorte que (i) le faisceau de mesure de la source de lumière soit réfléchi à travers le cube de coin vers le miroir plan, et le faisceau de mesure réfléchi du miroir plan soit de nouveau réfléchi à travers le cube de coin, et (ii) le mouvement du cube de coin dans au moins une direction prédéterminée ajuste la focalisation des faisceaux de mesure le long de la ligne de visée, d'une manière qui est sensiblement non affectée par le mouvement du cube de coin dans des directions transversales à la direction prédéterminée ou par des rotations du cube de coin par rapport à la direction prédéterminée.

5. Appareil selon une quelconque revendication précédente, comprenant en outre un moteur pour le déplacement de l'ensemble optique et un codeur pour la surveillance de la position de l'ensemble optique.

6. Appareil selon une quelconque revendication précédente, dans lequel l'ensemble optique est mobile autour de deux axes différents.

7. Appareil selon une quelconque revendication précédente, dans lequel l'appareil est agencé pour diriger un faisceau de pointage, présentant une longueur d'onde qui est dans une plage de longueur d'onde visible et qui est différente d'une longueur d'onde du faisceau de mesure, le long du trajet optique du faisceau de mesure vers l'objet.

8. Appareil selon une quelconque revendication précédente, comprenant en outre un photodétecteur agencé de sorte qu'une distance de l'objet puisse être obtenue sur la base du faisceau de mesure reçu de l'objet.

9. Procédé de fabrication d'une structure, comprenant :

la production de la structure sur la base d'informations de conception ;

l'obtention d'informations de forme de structure par utilisation de l'appareil selon au moins l'une des revendications 1 à 8 ;

la comparaison des informations de forme obtenues avec les informations de conception.

10. Procédé de fabrication de la structure selon la revendication 9, comprenant en outre le retraitement de la structure sur la base du résultat de comparaison.

11. Procédé de fabrication de la structure selon la revendication 10, dans lequel le retraitement de la structure inclut la nouvelle production de la structure.

Drawing