SEE-THROUGH HEAD OR HELMET MOUNTED DISPLAY DEVICE

Description

[0001] The present invention relates to a see-through head or helmet mounted display device and a see-through head or helmet display system.

[0002] See-through head or helmet mounted display devices are used for creating an augmented reality vision, i.e. for superimposing images of both a physical world and of a display in a user's view. During the proper use of a see-through head or helmet mounted display device, it is thus possible that beside an image of the physical world passing through a see-through member of the head or helmet mounted display device an additional superimposed image of the display representing overlay information reaches the user's eye(s).

[0003] To allow the user accommodating his/her vision to both the superimposed images, a collimating optical system of the see-through head or helmet mounted display device is adapted to magnify the image of the display and to (virtually) project it to infinity. In other words: The image of the display of the see-through head or helmet mounted display device is represented by collimated visible light leaving the see-through head or helmet mounted display device in the direction of the user's eye(s), where it is focused by the human lens, which is accommodated to infinity, on the retina. In this sense, it is understood that collimating visible light emitted by the display means creating an image of the display at infinite distance.

[0004] In commonly known see-through head or helmet mounted display devices, the display is decoupled from the see-through member of the see-through head or helmet mounted display device. This design is necessary, because the displays in commonly known see-through head or helmet mounted display devices are not transparent for visible light. Thus the display has to be removed out of the line of sight or out of the field of view of the user using the see-through head or helmet mounted display device.

[0005] A problem of this approach, however, is that the visible light representing the image of the display, before being collimated into the user's eye by the collimating optical system, has to be conveyed into the line of sight or the field of view of the user by an additional conveying optical system. This additional conveying optical system, in turn, increases the weight and the size of the see-through head or helmet mounted display device.

[0006] US 2004/0108971 A1 discloses a head-mountable apparatus for transmitting an image to the user's eye using switchable holographic optical elements. In an embodiment, the apparatus comprises an array of LED triads provided on a light-transmitting screen. The light emitted by the LED triads passes through a micro-lens array which is configured to collimate the light, and then passes through a liquid crystal shutter towards an ESHC (electrically switchable holographic composition). The micro-lens array may be of a holographic design. The liquid crystal shutter is switchable between a first state, in which only light from the LED triads passes through, and a second state, in which the shutter is generally light-transmitting.

[0007] US 4,181,405 A2 discloses a head-mounted display which comprises a helmet visor, wherein a portion of the helmet visor is an optically transparent viewing medium. Attached to the optically transparent viewing medium is a display unit for conveying information to a user of the head-mounted display and a focusing arrangement for bringing the display unit into focus on a user's far field of view. The focusing arrangement may comprise a plurality of convex lenses which are arranged spaced apart from each other on the viewing medium.

[0008] US 2008/0151185 A1 discloses a retinal scanning image display apparatus capable of keeping an image position on the retina substantially constant even when an observer moves the pupil. This is achieved by a means for shifting a plurality of display segments relative to a plurality of optical elements according to a position signal representing the position of the pupil of the observer's eye.

[0009] EP 1 942 364 A1 is directed to an optical relay device which is adapted to transmit a collimated light beam provided by an image generating system into at least one eye of a user.

[0010] EP 2 447 758 discloses another embodiment of a display assembly with a display device and a microlens array. A plurality of pixels of the display device is provided for each microlens of the microlens array.

[0011] It is an object of embodiments of the present invention to provide a see-through head or helmet mounted display device of a lightweight and compact design.

[0012] This object is solved by a see-through head or helmet mounted display device according to claim 1.

[0013] The see-through head or helmet mounted display device comprises a see-through member having a see-through area. The see-through member includes a plurality of display segments. Each display segment is adapted to emit visible light. The plurality of display segments is provided within the see-through area in a mutually spaced manner such that the see-through area includes a see-through zone between each pair of adjacent display segments. The see-through zone allows visible light to pass through the see-through member. The see-through member further includes a plurality of holographic optical elements provided within the see-through area. Each holographic optical element is associated with a respective display segment, wherein each display segment is located in a focal plane of the associated holographic optical element and each holographic optical element is adapted to collimate the visible light emitted by the associated display segment.

[0014] As a consequence of the see-through zone between each pair of adjacent display segments allowing visible light to pass through the see-through member, visible light can pass between each pair of adjacent display segments via the see-through zone. As the plurality of the display segments form the display of the see-through head or helmet mounted display device, both visible light emitted by the display itself and visible light from the physical world can pass through the display. Hence, the display is transparent or at least semi-transparent. Therefore, it is possible to provide the display directly in the line of sight or in the field of view of the user, who uses the see-through head or helmet mounted display device. Only the plurality of holographic optical elements representing the collimating optical system of the see-through head or helmet mounted display device is mandatory, however, an additional conveying optical system for conveying visible light emitted by the display into the line of sight or the field of view is dispensable. This, in turn, allows a lightweight and compact design of the inventive see-through head or helmet mounted display device.

[0015] A further advantage of the inventive see-through head or helmet mounted display device results from the use of holographic optical elements. As being a hologram, a holographic optical element may be recorded directly on or in the see-through member, which is part of a see-through head or helmet mounted display device anyways. Thus, a use of real (micro-) lenses or (micro-) mirrors made of, for example, relatively heavy glass or plastic is not necessary. This allows to further decrease the weight and the size of the inventive see-through head or helmet mounted display device.

[0016] Another advantage of the inventive see-through head or helmet mounted display device arises from the use of a plurality of holographic optical elements: When using a single optical element instead of a plurality of holographic optical elements to collimate the visible light emitted by the display, the f-number of the single optical element (being defined as a ratio of a focal length of the single optical element divided by a size of an entrance pupil of the single optical element, where the size of the entrance pupil is defined by the distance between the two points on the profile of the entrance pupil farthest apart) has to be small, which leads to serious aberrations in the image of the display. In contrast to this, by employing a plurality of (relatively small) holographic optical elements instead of a (relatively large) single optical element (so to say: by dividing the single optical element into a plurality of holographic optical elements) and by associating each holographic optical element with one respective display segment, the f-number of each holographic optical element can be kept large. This allows an aberration free imaging of the display formed by the display segments.

[0017] The see-through member represents, for example, a substrate, a viewing port, a window, a visor, a glass, an eyepiece, an eyeglass, a corrective lens and/or a spectacle lens of the see-through head or helmet mounted display device. The see-through member may be made of glass or plastic. The see-through area, for example, is a part, a section, a region or an area of the see-through member, through which a user views through the see-through member during a proper use of the see-through head or helmet mounted display device. The see-through area and/or the see-through zone may be transparent and/or translucent for the whole visible light spectrum. In other words: Visible light may pass through the see-through area and/or the see-through zone without being scattered, reflected, refracted, deflected and/or absorbed.

[0018] The plurality of display segments can be arranged upon or inside the see-through member and/or the see-through area. For example, arranging the plurality of display segments inside the see-through member allows for a protection of the display segments against physical impact such as scratching. The arrangement of the plurality of display segments may be realized by fixing, gluing, bonding, welding, or printing as a circuit.

[0019] The see-through area of the see-through member may include the see-through zone also between each pair of adjacent holographic optical elements. The holographic optical elements may thus be mutually spaced. This allows visible light passing through the see-through member between the holographic optical elements via the see-through zone.

[0020] The plurality of display segments and/or the plurality of holographic optical elements may be provided in a rhombus-shaped, rectangular-shaped, or square-shaped manner across a respective two-dimensional array. The array may lie in a plane or curved arrangement area. The arrangement area may be imaginary or a surface of the see-through member. This allows a dense arrangement of the display segments and/or the holographic optical elements, while the display segments and/or the holographic optical elements can be still kept mutually spaced. Hence, the display can have a high resolution even though being transparent or at least semi-transparent.

[0021] A number of the plurality of display segments and/or a number of the plurality of holographic optical elements along one dimension of the two-dimensional array may be, for example, 5, 10, 50, or 200, or in a range of 5 to 10, 5 to 50, or 5 to 200. Additionally or alternatively, a number of the plurality of display segments and/or a number of the plurality of holographic optical elements in the two-dimensional array may be, for example, 25, 100, 2500, or 40000, or in a range of 25 to 100, 25 to 2500, or 25 to 40000. A large number of display segments, for example, has the advantage to increase the display size. As a consequence, the field of view of the see-through head or helmet mounted display device is large as well.

[0022] A separation distance between centers of adjacent display segments and/or a separation distance between centers of adjacent holographic optical elements may be, for example, 28 µm, 112 µm, 560 µm, or 1120 µm, or in a range of 28 µm to 112 µm, 28 µm to 560 µm, or 28 µm to 1120 µm.

[0023] A size of the display being formed by the plurality of display segments in a see-through head or helmet mounted display device may be defined as the maximum separation distance between the centers of two display segments of the display, i.e. the separation distance between the two display segments farthest apart in the display. Similarly, a size of the collimating optical system formed by the plurality of holographic optical elements in a see-through head or helmet mounted display device may be defined as the maximum separation distance between the centers of two display segments of the collimating optical system. A maximum separation distance between centers of two display segments of the display and/or a maximum separation distance between centers of two holographic optical elements of the plurality of holographic optical elements may be, for example, around 5,6 mm or around 8 mm, or in a range of 4 mm to 12 mm.

[0024] A holographic optical element may be recorded in an emergent holographic emulsions provided within the see-through area, in particular, on or in the see-through member. A holographic optical element may have magnifying optical properties such that a (virtual) image of the associated display segment is provided in infinity (i.e. at infinite distance). Such a holographic optical element allows a simple realization of a holographic optical element having a focal plane and being adapted to collimate visible light emitted by a display segment located in the focal plane of the holographic optical element.

[0025] In particular, in an example forming background art to the present invention, a holographic optical element may be a holographic converging lens (i.e. a transmission hologram of a converging lens). Such a holographic optical element allows arranging the display segment associated with the holographic optical element on a side of the holographic optical element facing away from an eye of a user, who views properly through the see-through head or helmet display device. Such an arrangement of the holographic optical element and the corresponding display segment relative to the eye of the user has the advantage that a mask (as described below) is dispensable. The holographic optical element may have rotationally symmetric imaging properties, for example, by being the transmission hologram of a rotationally symmetric, spherical and/or aspherical converging lens.

[0026] A holographic optical element is a holographic concave mirror (i.e. a reflection hologram of concave mirror). In particular, the holographic concave mirror is a reflective, concave and parabolic mirror (i.e. a reflection hologram of a reflective, concave, and parabolic mirror). Such a holographic optical element allows arranging the display segment associated with the holographic optical element on a side of the holographic optical element facing towards an eye of a user, who views properly through the see-through head or helmet display device. The holographic optical element may have rotationally symmetric imaging properties, for example, by being the reflection hologram of a rotationally symmetric, concave, parabolic mirror.

[0027] A holographic optical element may be adapted to deflect (i.e. reflect) visible light only within a deflection spectrum and to be transparent for visible light within a transmission spectrum, wherein the deflection spectrum and the transmission spectrum are spectrally disjoint. In other words: Each of the deflection spectrum and the transmission spectrum only cover a respective spectral section of the visible light spectrum and the deflection spectrum and the transmission spectrum do not overlap. This can be realized by holographically recording the holographic optical element using visible light only within the deflection spectrum. Such a holographic optical element is only reflective for visible light within deflection spectrum. Visible light within the transmission spectrum, in turn, passes through the holographic optical element without being refracted, reflected and/or absorbed by holographic optical element. Visible light representing an image of the physical world outside the see-through head or helmet mounted display device is thus not or only slightly affected by the presence of the holographic optical element.

[0028] In particular, a holographic optical element may be adapted such that the deflection spectrum consists of a band spectrum. The band spectrum may include a red color. The wavelength of the red color may be, for example, around 630 nm. However, any other color is conceivable, such as green or blue. A bandwidth of the band spectrum may be limited, for example, to around 30 nm. Such a holographic optical element only reflects visible light of a single color. Visible light of other colors passes through the holographic optical element unaffected. Simultaneously, such a holographic optical element allows collimating visible light within the deflection spectrum emitted by the display segment associated with the holographic optical element for creating a mono-chromatic image of the display segment at infinite distance.

[0029] Additionally or alternatively, a holographic optical element may be adapted such that the deflection spectrum includes plurality of band spectra (i.e. two, three, four, or more band spectra). In particular, a holographic optical element may be adapted such that the deflection spectrum includes a first band spectrum, a second band spectrum and third band spectrum. The first band spectrum may include a red color, the second band spectrum may include a green color and/or the third band spectrum may include a blue color. The band spectra, in particular, the first, the second and the third band spectrum may be spectrally disjoint and mutually separated by the transmission spectrum of the holographic optical element. A bandwidth of one of the band spectra, in particular, a bandwidth of the first, the second and/or the third band spectrum may be limited, for example, to around 30 nm. As a consequence, the deflection spectrum of the holographic optical element may consist of narrow band spectra, wherein each band spectrum only reflects visible light of a single color. Visible light of colors not within the deflection spectrum, i.e. visible light of colors within the transmission spectrum, passes through the holographic optical element unaffected. Simultaneously, such a holographic optical element allows collimating visible light within the deflection spectrum emitted by the display segment associated with the holographic optical element for creating a multi-chromatic image of the display segment at infinite distance.

[0030] For each holographic optical element a band pass filter may be provided. The band pass filter may be adapted to filter out (i.e. to reject, reflect and/or absorb) visible light only within the deflection spectrum of the holographic optical element and to transmit visible light within the transmission spectrum of the holographic optical element. The band pass filter may be a notch filter, an interference filter, a Fabry-Perot-cavity or the like. In particular, the band pass filter may be provided on a side of the holographic optical element facing away from an eye of a user, who views properly through the see-through head or helmet display device, such that visible light from the physical world within the deflection spectrum of the holographic optical element is prevented from passing through the holographic optical element. This allows that visible light, which represents an image of the physical world and whose color falls within the deflection spectrum of the holographic optical element, does not perturb, disturb or pollute the superimposed image of the display in the eye of the user.

[0031] A display segment may be adapted to emit visible light only within an emission spectrum. In particular, the display segment may be adapted such that the emission spectrum includes an emission band spectrum with a limited emission bandwidth. The emission band spectrum may include a red color. The wavelength of the red color may be, for example, around 630 nm. However, any other color is conceivable, such as green or blue. The emission bandwidth of the emission band spectrum may be limited, for example, to around 30 nm or smaller. Such a display segment allows for creating a mono-chromatic image.

[0032] Additionally or alternatively, a display segment may be adapted such that the emission spectrum includes a plurality of emission band spectra (i.e. two, three, four, or more band spectra). In particular, a display segment may be adapted such that the emission spectrum includes a first emission band spectrum, a second emission band spectrum and third emission band spectrum. The first emission band spectrum may include a red color, the second emission band spectrum may include a green color and/or the third emission band spectrum may include a blue color. The emission band spectra, in particular, the first, the second and the third emission band spectrum may be spectrally disjoint and mutually separated by a spectral section of the visible light spectrum. An emission bandwidth of one of the band spectra, in particular, an emission bandwidth of the first, the second and/or the third emission band spectrum may be limited, for example, to around 30 nm or smaller. Such a display segment allows for creating a multi-chromatic image.

[0033] In particular, a display segment may be adapted to emit visible light only within a deflection spectrum of the holographic optical element associated with the display segment. In other words: An emission spectrum of the display segment may be completely covered by the deflection spectrum of the associated holographic optical element such that the whole emission spectrum of the display segment is refracted or reflected by the associated holographic optical element. In particular, an emission bandwidth of a first, a second and/or a third emission band spectrum may be as wide as or narrower than a bandwidth of a first, a second and/or a third band spectrum. Thus, all or at least most of the light emitted by the display segment is collimated by the associated holographic optical element. This allows the design of an energy efficient see-through head or helmet display device generating bright display images.

[0034] A display segment includes a plurality of pixel units. Thus, the display is formed of a plurality of mutually spaced display segments, wherein each display segment is formed of a plurality of pixel units. As a consequence, on a macroscopic scale the display comprises a plurality of display segments, between which visible light can pass through. On a microscopic scale, in turn, each display segment itself may be regarded as a micro-display comprising a plurality of pixels units, wherein between adjacent pixel units not necessarily a see-through zone of the see-through member has to be provided allowing visible light to pass between the adjacent pixel units. This two-scale approach thus allows providing a transparent or at least semi-transparent display with high resolution.

[0035] The pixels units within a display segment may be mutually spaced. In particular, the plurality of pixels units of a display segment may be provided in the focal plane of the holographic optical element associated with the display segment. Within the display segment, the plurality of pixel units may be provided in a rhombus-shaped, rectangular-shaped, or square-shaped manner across a respective two-dimensional pixel array. The pixel array may lie in a plane or curved pixel arrangement area. The pixel arrangement area may be imaginary or a surface of the see-through member. The pixel arrangement area may coincide with an arrangement area for arranging the plurality of display segments.

[0036] A number of the plurality of pixel units along one dimension of the two-dimensional pixel array may be, for example, 3, 12, 60, or 120, or in a range of 3 to 12, 3 to 60, or 3 to 120. Additionally or alternatively, a number of the plurality of pixel units in the two-dimensional pixel array may be, for example, 9, 144, 3600, or 14400, or in a range of 9 to 144, 9 to 3600, or 9 to 14400.

[0037] A separation distance between centers of adjacent pixel units (also called pitch) may be, for example, around 5 µm. A size of a display segment being formed by the plurality of pixel units within the display segment may be defined as the maximum pixel separation distance between the centers of two pixel units of the display segment, i.e. the pixel separation distance between the two pixel units farthest apart in the display segment. A maximum pixel separation distance between centers of two pixel units of a display segment may be, for example, around 15 µm, 21 µm, 60 µm, 85 µm, 300 µm, 424 µm, 600 µm, or 849 µm.

[0038] A pixel unit may be adapted to emit visible light. For example, a pixel unit may be an organic light emitting diode (OLED), a micro-laser or a liquid crystal display (LCD) element. Thus, the plurality of pixel units may be employed to realize that the display segment comprising the pixel unit is adapted to emit, for example, visible light only within a specific monochromatic emission spectrum.

[0039] Additional or alternatively, a pixel unit of a display segment may comprise three sub-pixel units, wherein the sub-pixel units are adapted to emit visible light of three different colors. For example, a first sub-pixel unit may emit red, a second sub-pixel unit may emit green and/or a third sub-pixel unit may emit blue light. The sub-pixel units may be organic light emitting diodes (OLED), a micro-laser or a liquid crystal display (LCD) element. Thus, the plurality of sub-pixel units may be employed to realize that the display segment comprising the sub-pixel units is adapted to emit visible light only within a specific multi-chromatic emission spectrum.

[0040] The sub-pixel units of a display segment may be stacked substantially along a depth of field of the holographic optical element associated with the display segment. This allows a compact design of the see-through head or helmet display device for generating multi-chromatic display images.

[0041] A light emission surface of a pixel unit and/or a light emission surface of a sub-pixel unit may be square-shaped or rectangular-shaped. A light emission surface may be, for example, around 25 µm².

[0042] A holographic optical element may deflect visible light only with its deflection region. The deflection region may be the entrance pupil of the holographic optical element. A size of the holographic optical element may be defined as the maximum point separation distance between two points within the deflection region of the holographic optical element, i.e. the point separation distance between the two points farthest apart in the deflection region. The maximum point separation distance of a holographic optical element may be larger than a size of the display segment associated with the holographic optical element. In other words: The entrance pupil of the holographic optical element may be larger than the size of the associated display segment. Additionally or alternatively, the maximum point separation distance of a holographic optical element may be smaller than, for example, 2 mm or 3 mm or the size of a pupil of a human eye.

[0043] A display segment may be provided with a mask such that the display segment emits the visible light only towards the holographic optical element associated with the display segment. The mask may comprise material opaque or reflective for the visible light emitted by the display segment. The mask may surround all the sides of the display segment despite the one side of the display segment that faces towards the associated holographic optical element.

[0044] The holographic optical elements and the associated display segments may be adapted and/or arranged such that an inclination angle between a propagation direction of visible light collimated by a holographic optical element associated with a display segment displaced by a displacement distance from a center of the plurality of display segments and a propagation direction of visible light collimated by a holographic optical element associated with a display segment located at the center of the plurality of display segments increases with increasing displacement distance in such a manner that the visible light collimated by each holographic optical element passes through an exit pupil of the see-through head or helmet mounted display device. Such an arrangement may be realized as follows: An optical axis of a holographic optical element is by definition oriented perpendicular to the focal plane of the holographic optical element. The orientation of the optical axis can thus be adjusted and fixed during the recording of the holographic optical element by tilting the object (i.e. the lens or the mirror or the like) being imaged as hologram. The orientation of the optical axis of the holographic optical element and the positioning of the associated display segment in the focal plane of the holographic optical element then allow adjusting the inclination angle. The inclination angle may be regarded as half the angle of view (i.e. the angle of the view cone) of the see-through head or helmet display device. As a consequence, the visible light emitted by all the display segments and collimated by the associated holographic optical elements passes through one exit pupil. Hence, all or most of the light power of the display can be collimated into the user's eye leading to low power requirements of the see-through head or helmet mounted display device.

[0045] In particular, the holographic optical elements and the associated display segments may be adapted and arranged such that the exit pupil of the see-through head or helmet mounted display device is smaller than, for example, 2 mm or 3mm. Additionally or alternatively, the holographic optical elements and the associated display segments may be adapted and arranged such that the inclination angle is, for example, 40°/2, 50°/2, or 70°/2, or in a range of 40°/2 to 50°/2, or 40°/2 to 70°/2.

[0046] The see-through head or helmet display device may further comprise a frame, an actuator for tilting the plurality of display segments and the plurality of holographic optical elements relative to the frame, an image capturing device for capturing an image of a user's eye and for generating a position signal representing a position of a pupil of the user's eye, and a controller for controlling the actuator based on the position signal such that the position of the exit pupil of the see-through head or helmet mounted display device coincides with the position of the pupil of the user's eye. In other words: All collimated light originating from the display and leaving the see-through head or helmet display device reaches the pupil of the user's eye, even when the pupil of the user's eye is moving.

[0047] Additionally or alternatively, the see-through head or helmet display device may comprise a beam expander, which is adapted to expand the visible light collimated by the holographic optical segments. This allows enlarging the profile of collimated beams such that all the beams pass (at least partially) through the pupil of the user's eye.

[0048] The beam expander may be provided on a side of the plurality of holographic optical segments facing towards the user's eye and on a side of the plurality of display segments facing towards the user's eye. The beam expander may consist of two holographic optical elements. The size of these holographic optical elements may be larger than the size of the display.

[0049] Additionally or alternatively, the see-through head or helmet display device may comprise a shifter for shifting the plurality of display segments relative to the plurality of holographic optical elements along the focal planes of the holographic optical elements, an image capturing device for capturing an image of the pupil and for generating a position signal representing a position of the pupil, and a controller for controlling the shifter based on the position signal such that the position of the exit pupil coincides with the position of the pupil. In other words: The display formed by the display segments is shifted relative to the collimating optical system formed by the plurality of holographic optical elements, thereby shifting each display segment within the focal plane of the corresponding holographic optical element. Hence, all collimated light originating from the display and leaving the see-through head or helmet display device reaches the pupil of the user's eye, even when the pupil of the user's eye is moving.

[0050] A see-through head or helmet display system comprises two see-through head or helmet display devices. This allows employing one see-through head or helmet display device for each eye of the user.

[0051] Throughout this description, when referring to a feature characterizing an element of a plurality of elements, each of the plurality of elements may be characterized by the corresponding feature.

[0052] The invention will be elucidated further in the following on the basis of the appended drawings, of which:

Fig. 1

shows schematically, in top view, an example of a see-through head or helmet mounted display system,

Fig. 2

shows schematically, at the center in side view, an example of a see-through head or helmet mounted display device, left in three-dimensional view, a plurality of holographic optical elements, and, right in three-dimensional view, a plurality of display segments,

Fig. 3a

shows schematically, in three-dimensional view, the plurality of holographic optical elements and the plurality of display segments from Fig. 2,

Fig. 3b

shows schematically, in side view, the plurality of holographic optical elements and the plurality of display segments from Fig. 2,

Fig. 4a

shows schematically, in three-dimensional view, a display segment and an associated holographic optical element,

Figs. 4b and 4c

show schematically, in side view, the display segment and the holographic optical element from Fig. 4a,

Fig. 5

shows schematically a deflection spectrum of a holographic optical element and an emission spectrum of an associated display segment,

Fig. 6

shows schematically, in side view, another example of a see-through head or helmet mounted display device,

Fig. 7

shows schematically, in top view, an example of an array of two display segments,

Fig. 8

shows schematically, in top view, an example of an array of nine display segments,

Fig. 9

shows schematically, in side view, an example of a pixel unit comprising a stack of sub-pixel units,

Figs. 10 and 11

show schematically, in side view, the see-through head or helmet mounted display device from Fig. 6,

Fig. 12

shows schematically, in side view, a modification of the see-through head or helmet mounted display device from Fig. 6, and

Fig. 13

shows schematically, in side view, another modification of the see-through head or helmet mounted display device from Fig. 6.

Figs. 14a and 14b

show schematically, in side view, still another modification of the see-through head or helmet mounted display device from Fig. 6.

[0053] The see-through head or helmet mounted display system 1, as shown in Fig. 1, comprises two see-through head or helmet mounted display devices 10, one for each eye 16 of a user. Each see-through head or helmet mounted display device 10 serves for creating an augmented reality vision, i.e. for superimposing images of both a physical world 12 and of a display 14 in a user's eye 16. The display 14 is directly arranged in the line of sight or in the field of view of the user. During the proper use of a see-through head or helmet mounted display device 10, it is thus possible that beside an image of the physical world 12 passing through a see-through member 18 of the head or helmet mounted display device 10 an additional superimposed image of the display 14 reaches the user's eye(s) 16.

[0054] As shown in Fig. 2, 3a and 3b, the see-through member 18 includes a plurality of display segments 20 for emitting visible light. The display segments 20 are provided within a see-through area 22 of see-through member 18 in a mutually spaced manner such that the see-through area 22 includes a see-through zone 24 between each pair of adjacent display segments 20, see Fig. 3a and 3b. The see-through member 18 further includes a plurality of holographic optical elements 26 provided within the see-through area 22. Each holographic optical element 26 is associated with one respective display segment 20. The holographic optical elements 26 are mutually spaced such that the see-through zone 24 is also provided between each pair of adjacent holographic optical elements 26. The see-through zone 24 is transparent and allows visible light to pass through the see-through member 18 between the display segments 20 and the holographic optical elements 26. This makes the display 14 locally transparent. Thus, an image of the physical world 12 can pass the see-through member 18 via the see-through zone 24.

[0055] As shown in Fig. 2 and 3b, the holographic optical elements 26 are recorded directly in the see-through member 18. In particular, each holographic optical element 26 is a reflection hologram of a concave and parabolic mirror as shown in Fig. 4c, i.e. each holographic optical element 26 has magnifying optical properties.

[0056] As shown in Fig. 4b and 4c, each display segment 20 is arranged on a side of the associated holographic optical element 26 facing towards the eye 16 and is located in a focal plane of the associated holographic optical element 26. Each holographic optical element 26 collimates the visible light emitted by the associated display segment 20 towards the eye 16.

[0057] As shown, for example, in Fig. 2, the plurality of display segments 20 and the plurality of holographic optical elements 26 are provided equidistantly along respective one-dimensional straight lines 28a, 28b, 28c, 28d. Further, the plurality of display segments 20 and the plurality of holographic optical elements 26 are provided in a rhombus-shaped manner across respective two-dimensional plane arrays spanned by the lines 28a, 28b and by the lines 28c, 28d, respectively. The arrays lie parallel to a surface of the see-through member 18.

[0058] As shown in the wavelength(A)-reflectivity(R)-diagram of Fig. 5, each holographic optical element 26 reflects visible light only within a deflection spectrum 30. The deflection spectrum 30 only covers a spectral section of the visible light spectrum 32. Further, each holographic optical element 26 is transparent for visible light within a transmission spectrum 34. The transmission spectrum 34 only covers a spectral section of the visible light spectrum 32 such that the deflection spectrum 30 and the transmission spectrum 34 do not overlap (i.e. are spectrally disjoint). Thus, visible light within the transmission spectrum 34 passes through the holographic optical element 26 without being refracted or reflected. The deflection spectrum 30 is a band spectrum including a red color λ_r, for example, around 630 nm. A bandwidth 36 (FWHM) of the band spectrum 30 is limited, for example, to around 30 nm.

[0059] As shown in Fig. 6, for each holographic optical element 26a, 26b a band pass filter 38 is provided. The band pass filter 38 is adapted to filter out visible light only within the deflection spectrum 30 and to transmit visible light within the transmission spectrum 34. The band pass filter is provided on a side of the holographic optical element 26 facing away from the eye 16, such that visible light of the physical world 12 within the deflection spectrum 32 is prevented from passing through the holographic optical element 26. This allows that visible light, which represents an image of the physical world 12 and whose color falls within the deflection spectrum 32 of the holographic optical element 26, does not perturb, disturb or pollute the superimposed image of the display 14 in the eye 16.

[0060] As shown in Fig. 5, each display segment 20 emits visible light only within an emission spectrum 40 including an emission band spectrum 40. The emission band spectrum 40 includes a red color λ_r, for example, around 630 nm. An emission bandwidth 42' (FWHM) of the emission band spectrum 40 is limited, for example, to around 30 nm or smaller. Therefore, the display segment 20 emits visible light only within the deflection spectrum 30 of the holographic optical element 26 associated with the display segment 20. Such a display segment allows for creating a mono-chromatic image.

[0061] As shown in Fig. 7 and 8, each display segment 20 is formed of a plurality of mutually spaced pixel units 42. As a consequence, on a macroscopic scale the display 14 comprises a plurality of display segments 20, between which visible light can pass through via the see-through zones 24. On a microscopic scale, in turn, each display segment 20 itself may be regarded as a micro-display comprising a plurality of pixels units 42. This two-scale approach allows providing a transparent or at least semi-transparent display 14 with high resolution.

[0062] The plurality of pixels units 42 of each display segment 20 is provided in the focal plane of the holographic optical element 26 associated with the display segment 20. As shown in the example of Fig. 7, within the display segment 20 the plurality of pixels units 42 is provided equidistantly along straight one-dimensional pixel lines 44a, 44b. Further, within each display segment 20, the plurality of pixel units 42 is provided in rectangular-shaped or square-shaped manner across a two-dimensional plane pixel array spanned by the pixel lines 44a, 44b, see Fig. 7 and 8. For example, along a one-dimensional pixel line, the number of the plurality of pixel units is 2 (Fig. 2 and 8) or 4 (Fig. 7), wherein across the pixel array the number of the plurality of pixel units is 4 (Fig. 2 and 8) or 16 (Fig. 7).

[0063] As shown in the example of Fig. 7, a pixel separation distance 48 between centers of adjacent pixel units 42 (also called pitch) is, for example, around 5 µm, whereas a pixel separation distance 50 between centers of the two pixel units 42 farthest apart in the display segment 20 is, for example, around 21 µm. A light emission surface of each pixel unit 42 is square-shaped or rectangular-shaped and, for example, around 25 µm². In Fig. 7 and 8, the sizes of the display segments 20 are the same. The size of a display segment 20 is defined as the pixel separation distance 50 between the centers of the two pixel units 42 farthest apart in the display segment 20, see Fig. 7.

[0064] Each pixel unit 42 is, for example, an organic light emitting diode (OLED) or a micro-laser, see e.g. Fig. 8, for emitting visible light in a monochromatic emission spectrum. Alternatively, as shown in Fig. 9, a pixel unit 42 of a display segment 20 may comprise three sub-pixel units 52a, 52b, 52c, wherein the sub-pixel units 52a, 52b, 52c emit visible light of three different colors, namely red, green and blue. The sub-pixel units may be organic light emitting diodes (OLED) or a micro-laser, too, and are stacked substantially along a depth of field 54 of the holographic optical element 26 associated with the display segment 20, compare Fig. 4c and 9.

[0065] As shown, for example, in Fig. 3b, 4b, 6 and 9, each display segment 20 is provided with a mask 56' of material being opaque for visible light. The mask 56' is provided such that the display segment 20, 20a, 20b emits the visible light only towards the holographic optical element 26, 26a, 26b associated with the display segment 20, 20a, 20b. The mask 56' surrounds all the sides of the display segment 20, 20a, 20b despite the one side of the display segment 20, 20a, 20b that faces towards the associated holographic optical element 26, 26a, 26b.

[0066] As shown in Fig. 6, 10, 11, 12, 14a and 14b, the holographic optical elements 26a, 26b are recorded and the associated display segments 20a, 20b are arranged relative to the holographic optical elements 26a, 26b such that an inclination angle β between a propagation direction 56a of visible light collimated by a holographic optical element 26a associated with a display segment 20a displaced by a displacement distance X from a center 58 of the plurality of display segments 20a, 20b and a propagation direction 56b of visible light collimated by a holographic optical element 26b associated with a display segment 20b placed at the center 58 of the plurality of display segments 20a, 20b increases with increasing displacement distance X in such a manner that the visible light collimated by each holographic optical element 26a, 26b passes through an exit pupil 60 of the see-through head or helmet mounted display device 10. The inclination angle β may be regarded as half the angle of view of the see-through head or helmet display device 10. Hence, all or most of the light power of the display 14 can be collimated into the user's eye 16, making the see-through head or helmet mounted display device 10 energy efficient.

[0067] To avoid a situation as shown in Fig. 11 or 14a, where the exit pupil 60 of the see-through head or helmet mounted display device 10 does not coincide with a pupil 62 of the user's eye 16, the see-through head or helmet display device 10 may comprise a frame 64, an actuator 66 for tilting the plurality of display segments 20a, 20b and the plurality of holographic optical elements 26a, 26b relative to the frame 64, an image capturing device 68 for capturing an image of the pupil 62 and for generating a position signal representing a position of the pupil 62, and a controller 70 for controlling the actuator 66 based on the position signal such that the position of the exit pupil 60 coincides with the position of the pupil 62, compare Fig. 12. As a consequence, all collimated light originating from the display segments 26a, 26b and leaving the see-through head or helmet display device 10 reaches the pupil 62 of the user's eye 16, even when the pupil 62 or the eye 16 is moving.

[0068] Additionally or alternatively, as shown in Fig. 14a and 14b, the see-through head or helmet display device 10 may comprise a shifter 78 for shifting the plurality of display segments 20a, 20b relative to the plurality of holographic optical elements 26a, 26b along the focal planes of the holographic optical elements 26a, 26b, an image capturing device 68' for capturing an image of the pupil 62 and for generating a position signal representing a position of the pupil 62, and a controller 70' for controlling the shifter 78 based on the position signal such that the position of the exit pupil 60 coincides with the position of the pupil 62, compare Fig. 14b. As a consequence, all collimated light originating from the display segments 26a, 26b and leaving the see-through head or helmet display device 10 reaches the pupil 62 of the user's eye 16, even when the pupil 62 or the eye 16 is moving.

[0069] Additionally or alternatively, as shown in Fig. 13, the see-through head or helmet display device 10 may comprise a beam expander 72. The beam expander is provided on a side of the plurality of holographic optical segments 26a, 26b facing towards the user's eye 16 and on a side of the plurality of display segments 20a, 20b also facing towards the user's eye 16. The beam expander 72 consists of two holographic optical elements 74, 76 and expands the visible light collimated by all the holographic optical segments 26a, 26b. The size of these holographic optical elements 74, 76 is larger than the size of the display 14. This allows enlarging the profile of collimated beams leaving the see-through head or helmet display device 10 such that all the beams pass at least partially through the pupil 62 of the user's eye 16.

[0070] Unless expressly stated otherwise, identical reference symbols in the Figures stand for identical or identically-acting elements. Also, an arbitrary combination of the features and/or modifications elucidated in the Figures in connection with individual embodiments is conceivable.

Claims

1. A see-through head or helmet mounted display device (10), comprising:

a see-through member (18) having a see-through area (22),

wherein the see-through member (18) includes a plurality of display segments (20; 20a, 20b) configured to emit visible light and provided within the see-through area (22) in a mutually spaced manner such that the see-through area (22) includes a see-through zone (24) between each pair of adjacent display segments (20; 20a, 20), the see-through zones (24) allowing visible light to pass through the see-through member (18),

wherein the see-through member (18) further includes a plurality of holographic optical elements (26; 26a, 26b) provided within the see-through area (22), each holographic optical element (26; 26a, 26b) being associated with a respective display segment (20; 20a, 20b),

wherein each display segment (20; 20a, 20) is located in a focal plane of the associated holographic optical element (26; 26a, 26b) and each holographic optical element (26; 26a, 26b) is adapted to collimate the visible light emitted by the associated display segment (20; 20a, 20),

wherein the display segments are distributed in a two-dimensional array pattern and each display segment includes a plurality of pixel units distributed in a two-dimensional array pattern wherein a distance between adjacent display segments is larger than a distance between adjacent pixel units of a display segment,

wherein the holographic optical elements are arranged on a side of the display segments facing away from a user's eye when the see-through head or helmet mounted display device is worn by a user, and

wherein each holographic optical element is designed as a holographic concave mirror adapted to reflect visible light emitted by the associated display segment towards the user's eye.

2. See-through head or helmet mounted display device according to claim 1, wherein each holographic optical element (26; 26a, 26b) is adapted to deflect visible light only within a deflection spectrum (30) and to be transparent for visible light within a transmission spectrum (34), the deflection spectrum (30) and the transmission spectrum (34) being spectrally disjoint.

3. See-through head or helmet mounted display device according to claim 2, wherein each holographic optical element (26; 26a, 26b) is further adapted such that the deflection spectrum (30) consists of a band spectrum, and a bandwidth (36) of the band spectrum being limited, in particular, to around 30 nm.

4. See-through head or helmet mounted display device according to claim 2 or 3, wherein each holographic optical element (26; 26a, 26b) is further adapted such that the deflection spectrum (30) includes a first band spectrum including a red color, a second band spectrum including a green color and a third band spectrum including a blue color, the first, the second and the third band spectrum being spectrally disjoint and mutually separated by the transmission spectrum (34), and a bandwidth of the first, the second and/or the third band spectrum being limited, in particular, to around 30 nm.

5. See-through head or helmet mounted display device according to one of claims 2 to 4,
wherein for each holographic optical element (26; 26a, 26b) a band pass filter (38) is provided, which is adapted to filter out visible light only within the deflection spectrum (30) of the holographic optical element (26; 26a, 26b) and to transmit visible light within the transmission spectrum (34) of the holographic optical element (26; 26a, 26b), and wherein the band pass filter (38) is provided on a side of the holographic optical element (26; 26a, 26b) facing away from an eye (16) of a user such that visible light within the deflection spectrum (30) of the holographic optical element (26; 26a, 26b) is prevented from passing through the holographic optical element (26; 26a, 26b).

6. See-through head or helmet mounted display device according to one of claims 2 to 5,
wherein each display segment (20; 20a, 20b) is adapted to emit visible light only within a deflection spectrum (30) of the holographic optical element (26; 26a, 26b) associated with the display segment (20; 20a, 20b).

7. See-through head or helmet mounted display device according to one of claims 1 to 6,
wherein each pixel unit (42) of a display segment (20; 20a, 20b) comprises a stack of three sub-pixel units (52a, 52b, 52c) being stacked substantially along a depth of field (54) of the holographic optical element (26; 26a, 26b) associated with the display segment (20; 20a, 20b).

8. See-through head or helmet mounted display device according to one of claims 1 to 7,
wherein each display segment (20; 20a, 20b) is provided with a mask (56') of material being opaque or reflective for visible light such that the display segment (20; 20a, 20b) emits the visible light only towards the holographic optical element (26; 26a, 26b) associated with the display segment (20; 20a, 20b).

9. See-through head or helmet mounted display device according to one of claims 1 to 8,
wherein the holographic optical elements (26; 26a, 26b) and the associated display segments (20; 20a, 20b) are adapted and arranged such that an inclination angle (β) between a propagation direction (56a) of visible light collimated by a holographic optical element (26a) associated with a display segment (20a) displaced by a displacement distance (X) from a center (58) of the plurality of display segments (20a, 20b) and a propagation direction (56b) of visible light collimated by a holographic optical element (26b) associated with a display segment (20b) located at the center (58) of the plurality of display segments (20a, 20b) increases with increasing displacement distance (X) in such a manner that the visible light collimated by each holographic optical element (26a, 26b) passes through an exit pupil (60) of the see-through head or helmet mounted display device (10).

10. See-through head or helmet mounted display device according to claim 9, comprising:

- a frame (64),

- an actuator (66) for tilting the plurality of display segments (20; 20a, 20b) and the plurality of holographic optical elements (26; 26a, 26b) relative to the frame (64),

- an image capturing device (68) for capturing an image of a pupil (62) of user's eye (16) and for generating a position signal representing a position of the pupil (62) of the user's eye (16), and

- a controller (70) for controlling the actuator (66) based on the position signal such that the position of the exit pupil (60) of the see-through head or helmet mounted display device (10) coincides with the position of the pupil (62) of the user's eye (16).

11. See-through head or helmet mounted display device according to claim 9 or 10, comprising:

- a shifter (78) for shifting the plurality of display segments (20a, 20b) relative to the plurality of holographic optical elements (26a, 26b) along the focal planes of the holographic optical elements (26a, 26b),

- an image capturing device (68') for capturing an image of a pupil (62) of user's eye (16) and for generating a position signal representing a position of the pupil (62) of the user's eye (16), and

- a controller (70') for controlling the shifter (78) based on the position signal such that the position of the exit pupil (60) of the see-through head or helmet mounted display device (10) coincides with the position of the pupil (62) of the user's eye (16).

12. See-through head or helmet mounted display device according to one of claims 1 to 11, comprising:
a beam expander (72) for expanding the visible light collimated by the holographic optical segments (26; 26a, 26b), the beam expander (72) being provided on both a side of the plurality of the holographic optical segments (26; 26a, 26b) facing towards the user's eye (16) and a side of the plurality of display segments (20; 20a, 20b) facing towards the user's eye (16).

Ansprüche

1. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung (10), umfassend:

ein durchsichtiges Element (18) mit einem durchsichtigen Bereich (22),

wobei das durchsichtige Element (18) eine Mehrzahl von Anzeigesegmenten (20; 20a, 20b) enthält, die so eingerichtet sind, dass sie sichtbares Licht emittieren, und innerhalb des durchsichtige Bereichs (22) in einer gegenseitig beabstandeten Weise vorgesehen sind, so dass der durchsichtige Bereich (22) eine durchsichtige Zone (24) zwischen jedem Paar benachbarter Anzeigesegmente (20; 20a, 20) enthält, wobei die durchsichtige Zonen (24) sichtbares Licht durch das durchsichtige Element (18) hindurchtreten lassen,

wobei das durchsichtige Element (18) ferner eine Mehrzahl von holografischen optischen Elementen (26; 26a, 26b) umfasst, die innerhalb des durchsichtigen Bereichs (22) vorgesehen sind, wobei jedes holografische optische Element (26; 26a, 26b) einem jeweiligen Anzeigesegment (20; 20a, 20b) zugeordnet ist,

wobei jedes Anzeigesegment (20; 20a, 20) in einer Brennebene des zugeordneten holografischen optischen Elements (26; 26a, 26b) angeordnet ist und jedes holografische optische Element (26; 26a, 26b) angepasst ist, um das von dem zugeordneten Anzeigesegment (20; 20a, 20) emittierte sichtbare Licht zu kollimieren,

wobei die Anzeigesegmente in einem zweidimensionalen Anordnungsmuster verteilt sind und jedes Anzeigesegment eine Mehrzahl von Pixeleinheiten umfasst, die in einem zweidimensionalen Anordnungsmuster verteilt sind, wobei ein Abstand zwischen benachbarten Anzeigesegmenten größer ist als ein Abstand zwischen benachbarten Pixeleinheiten eines Anzeigesegments,

wobei die holografischen optischen Elemente auf einer Seite der Anzeigesegmente angeordnet sind, die von einem Auge eines Benutzers abgewandt ist, wenn die durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung von einem Benutzer getragen wird, und

wobei jedes holografische optische Element als ein holografischer konkaver Spiegel gestaltet ist, der angepasst ist, um von dem zugeordneten Anzeigesegment emittiertes sichtbares Licht in Richtung des Auges des Benutzers zu reflektieren.

2. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach Anspruch 1,
wobei jedes holografische optische Element (26; 26a, 26b) angepasst ist, um sichtbares Licht nur innerhalb eines Ablenkungsspektrums (30) abzulenken und für sichtbares Licht innerhalb eines Transmissionsspektrums (34) transparent zu sein, wobei das Ablenkungsspektrum (30) und das Transmissionsspektrum (34) spektral disjunkt sind.

3. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach Anspruch 2,
wobei jedes holografische optische Element (26; 26a, 26b) ferner so angepasst ist, dass das Ablenkungsspektrum (30) aus einem Bandspektrum besteht und eine Bandbreite (36) des Bandspektrums insbesondere auf etwa 30 nm begrenzt ist.

4. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach Anspruch 2 oder 3,
wobei jedes holografische optische Element (26; 26a, 26b) ferner so angepasst ist, dass das Ablenkungsspektrum (30) ein erstes Bandspektrum, das eine rote Farbe enthält, ein zweites Bandspektrum, das eine grüne Farbe enthält, und ein drittes Bandspektrum umfasst, das eine blaue Farbe enthält, wobei das erste, das zweite und das dritte Bandspektrum spektral disjunkt und durch das Transmissionsspektrum (34) voneinander getrennt sind und eine Bandbreite des ersten, des zweiten und/oder des dritten Bandspektrums insbesondere auf etwa 30 nm begrenzt ist.

5. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach einem der Ansprüche 2 bis 4,
wobei ein Bandpassfilter (38) für jedes holographische optische Element (26; 26a, 26b) vorgesehen ist, der angepasst ist, um sichtbares Licht nur innerhalb des Ablenkungsspektrums (30) des holographischen optischen Elements (26; 26a, 26b) herauszufiltern und sichtbares Licht innerhalb des Transmissionsspektrums (34) des holografischen optischen Elements (26; 26a, 26b) zu übertragen, und wobei der Bandpassfilter (38) auf einer Seite des holografischen optischen Elements (26; 26a, 26b) vorgesehen ist, die von einem Auge (16) eines Benutzers abgewandt ist, so dass sichtbares Licht innerhalb des Ablenkungsspektrums (30) des holografischen optischen Elements (26; 26a, 26b) daran gehindert wird, durch das holografische optische Element (26; 26a, 26b) hindurchzutreten.

6. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach einem der Ansprüche 2 bis 5,
wobei jedes Anzeigesegment (20; 20a, 20b) angepasst ist, um sichtbares Licht nur innerhalb eines Ablenkungsspektrums (30) des holografischen optischen Elements (26; 26a, 26b) zu emittieren, das dem Anzeigesegment (20; 20a, 20b) zugeordnet ist.

7. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach einem der Ansprüche 1 bis 6,
wobei jede Pixeleinheit (42) eines Anzeigesegments (20; 20a, 20b) einen Stapel von drei Subpixeleinheiten (52a, 52b, 52c) umfasst, die im Wesentlichen entlang einer Schärfentiefe (54) des holografischen optischen Elements (26; 26a, 26b) gestapelt sind, das dem Anzeigesegment (20; 20a, 20b) zugeordnet ist.

8. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach einem der Ansprüche 1 bis 7,
wobei jedes Anzeigesegment (20; 20a, 20b) mit einer Maske (56') aus einem Material versehen ist, das für sichtbares Licht undurchsichtig oder reflektierend ist, so dass das Anzeigesegment (20; 20a, 20b) das sichtbare Licht nur in Richtung des holografischen optischen Elements (26; 26a, 26b) emittiert, das dem Anzeigesegment (20; 20a, 20b) zugeordnet ist.

9. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach einem der Ansprüche 1 bis 8,
wobei die holografischen optischen Elemente (26; 26a, 26b) und die zugeordneten Anzeigesegmente (20; 20a, 20b) derart angepasst und angeordnet sind, dass ein Neigungswinkel (β) zwischen einer Ausbreitungsrichtung (56a) von sichtbarem Licht, das durch ein holografisches optisches Element (26a) kollimiert wird, das einem Anzeigesegment (20a) zugeordnet ist, das um einen Verschiebungsabstand (X) von einer Mitte (58) der Mehrzahl von Anzeigesegmenten (20a, 20b) versetzt ist, und eine Ausbreitungsrichtung (56b) von sichtbarem Licht, das durch ein holografisches optisches Element (26b) kollimiert wird, das einem Anzeigesegment (20b) zugeordnet ist, das in der Mitte (58) der Mehrzahl von Anzeigesegmenten (20a, 20b) angeordnet ist, mit zunehmendem Verschiebungsabstand (X) derart zunimmt, dass das sichtbare Licht, das von jedem holografischen optischen Element (26a, 26b) kollimiert wird, durch eine Austrittspupille (60) der durchsichtigen Kopf- oder Helmmontierten Anzeigevorrichtung (10) hindurchtritt.

10. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach Anspruch 9, umfassend:

- einen Rahmen (64),

- einen Aktuator (66) zum Neigen der Mehrzahl von Anzeigesegmenten (20; 20a, 20b) und der Mehrzahl von holografischen optischen Elemente (26; 26a, 26b) relativ zum Rahmen (64),

- eine Bilderfassungsvorrichtung (68) zum Erfassen eines Bildes einer Pupille (62) eines Auges (16) des Benutzers und zum Erzeugen eines Positionssignals, das eine Position der Pupille (62) des Auges (16) des Benutzers darstellt, und

- eine Steuerung (70) zum Steuern des Aktuators (66) basierend auf dem Positionssignal derart, dass die Position der Austrittspupille (60) der durchsichtigen Kopf- oder Helmmontierten Anzeigevorrichtung (10) mit der Position der Pupille (62) des Auges (16) des Benutzers zusammenfällt.

11. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach Anspruch 9 oder 10, umfassend:

- einen Schieber (78) zum Verschieben der Mehrzahl von Anzeigesegmenten (20a, 20b) relativ zur Mehrzahl von holografischen optischen Elementen (26a, 26b) entlang der Brennebenen der holografischen optischen Elemente (26a, 26b),

- eine Bilderfassungsvorrichtung (68') zum Erfassen eines Bildes einer Pupille (62) eines Auges (16) des Benutzers und zum Erzeugen eines Positionssignals, das eine Position der Pupille (62) des Auges (16) des Benutzers darstellt, und

- eine Steuerung (70') zum Steuern des Schiebers (78) basierend auf dem Positionssignal derart, dass die Position der Austrittspupille (60) der durchsichtigen Kopf- oder Helmmontierten Anzeigevorrichtung (10) mit der Position der Pupille (62) des Auges (16) des Benutzers zusammenfällt.

12. Durchsichtige Kopf- oder Helmmontierte Anzeigevorrichtung nach einem der Ansprüche 1 bis 11, umfassend:
einen Strahlaufweiter (72) zum Aufweiten des durch die holografischen optischen Segmente (26; 26a, 26b) kollimierten sichtbaren Lichts, wobei der Strahlaufweiter (72) sowohl auf einer Seite der Mehrzahl der holografischen optischen Segmente (26; 26a, 26b), die dem Auge (16) des Benutzers zugewandt ist, als auch auf einer Seite der Mehrzahl von Anzeigesegmenten (20; 20a, 20b), die dem Auge (16) des Benutzers zugewandt ist, vorgesehen ist.

Revendications

1. Dispositif (10) d'affichage transparent monté sur la tête ou un casque, comprenant :

un élément transparent (18) ayant une aire transparente (22),

dans lequel l'élément transparent (18) inclut une pluralité de segments (20 ; 20a, 20b) d'affichage configurés pour émettre une lumière visible et prévus à l'intérieur de l'aire transparente (22) d'une manière mutuellement espacée de telle sorte que l'aire transparente (22) inclut une zone transparente (24) entre chaque paire de segments (20 ; 20a, 20b) d'affichage adjacents, les zones transparentes (24) permettant à la lumière visible de passer à travers l'élément transparent (18),

dans lequel l'élément transparent (18) inclut en outre une pluralité d'éléments optiques holographiques (26 ; 26a, 26b) prévus à l'intérieur de l'aire transparente (22), chaque élément optique holographique (26 ; 26a, 26b) étant associé avec un segment (20 ; 20a, 20b) d'affichage respectif,

dans lequel chaque segment (20 ; 20a, 20) d'affichage est situé dans un plan focal de l'élément optique holographique (26 ; 26a, 26b) associé et chaque élément optique holographique (26 ; 26a, 26b) est adapté à collimater la lumière visible émise par le segment (20 ; 20a, 20b) d'affichage associé,

dans lequel les segments d'affichage sont répartis selon un motif de réseau bidimensionnel et chaque segment d'affichage inclut une pluralité d'unités de pixels réparties selon un motif de réseau bidimensionnel dans lequel une distance entre segments d'affichage adjacents est plus grande qu'une distance entre unités de pixels adjacentes d'un segment d'affichage,

dans lequel les éléments optiques holographiques sont agencés sur un côté des segments d'affichage faisant face à l'opposé d'un œil d'un utilisateur lorsque le dispositif d'affichage transparent monté sur la tête ou un casque est porté par un utilisateur, et

dans lequel chaque élément optique holographique est conçu comme un miroir holographique concave adapté à réfléchir une lumière visible émise par le segment d'affichage associé vers l'œil de l'utilisateur.

2. Dispositif d'affichage transparent monté sur la tête ou un casque selon la revendication 1,
dans lequel chaque élément optique holographique (26 ; 26a, 26b) est adapté à dévier la lumière visible uniquement à l'intérieur d'un spectre (30) de déviation et à être transparent pour la lumière visible à l'intérieur d'un spectre (34) de transmission, le spectre (30) de déviation et le spectre (34) de transmission étant spectralement disjoints.

3. Dispositif d'affichage transparent monté sur la tête ou un casque selon la revendication 2,
dans lequel chaque élément optique holographique (26 ; 26a, 26b) est en outre adapté de telle manière que le spectre (30) de déviation consiste en un spectre de bande, et une largeur de bande (36) du spectre de bande étant limitée, en particulier, à environ 30 nm.

4. Dispositif d'affichage transparent monté sur la tête ou un casque selon la revendication 2 ou 3,
dans lequel chaque élément optique holographique (26 ; 26a, 26b) est en outre adapté de telle manière que le spectre (30) de déviation inclut un premier spectre de bande incluant une couleur rouge, une deuxième spectre de bande incluant une couleur verte et un troisième spectre de bande incluant une couleur bleue, le premier, le deuxième et le troisième spectre de bande étant spectralement disjoints et mutuellement séparés par le spectre (34) de transmission, et une largeur de bande du premier, du deuxième et/ou du troisième spectre de bande étant limitée, en particulier, à environ 30 nm.

5. Dispositif d'affichage transparent monté sur la tête ou un casque selon l'une des revendications 2 à 4,
dans lequel, pour chaque élément optique holographique (26 ; 26a, 26b), un filtre passe-bande (38) est prévu, qui est adapté à filtrer la lumière visible uniquement à l'intérieur du spectre (30) de déviation de l'élément optique holographique (26 ; 26a, 26b ) et à transmettre la lumière visible à l'intérieur du spectre (34) de transmission de l'élément optique holographique (26 ; 26a, 26b), et dans lequel le filtre passe-bande (38) est prévu sur un côté de l'élément optique holographique (26 ; 26a, 26b) faisant face à l'opposé d'un œil (16) d'un utilisateur de telle sorte que la lumière visible à l'intérieur du spectre (30) de déviation de l'élément optique holographique (26 ; 26a, 26b) est empêchée de passer à travers l'élément optique holographique (26 ; 26a, 26b).

6. Dispositif d'affichage transparent monté sur la tête ou un casque selon l'une des revendications 2 à 5,
dans lequel chaque segment (20 ; 20a, 20b) d'affichage est adapté à émettre une lumière visible uniquement à l'intérieur d'un spectre (30) de déviation de l'élément optique holographique (26 ; 26a, 26b) associé avec le segment (20 ; 20a, 20b) d'affichage.

7. Dispositif d'affichage transparent monté sur la tête ou un casque selon l'une des revendications 1 à 6,
dans lequel chaque unité (42) de pixels d'un segment (20 ; 20a, 20b) d'affichage comprend un empilement de trois unités (52a, 52b, 52c) de sous-pixels étant empilées sensiblement le long d'une profondeur de champ (54) de l'élément optique holographique (26 ; 26a, 26b) associé avec le segment (20 ; 20a, 20b) d'affichage.

8. Dispositif d'affichage transparent monté sur la tête ou un casque selon l'une des revendications 1 à 7,
dans lequel chaque segment (20 ; 20a, 20b) d'affichage est prévu avec un masque (56') d'un matériau étant opaque ou réfléchissant pour la lumière visible de manière à ce que le segment (20 ; 20a, 20b) d'affichage émette la lumière visible uniquement vers l'élément optique holographique (26 ; 26a, 26b) associé avec le segment (20 ; 20a, 20b) d'affichage.

9. Dispositif d'affichage transparent monté sur la tête ou un casque selon l'une des revendications 1 à 8,
dans lequel les éléments optiques holographiques (26 ; 26a, 26b) et les segments (20 ; 20a, 20b) d'affichage associés sont adaptés et agencés de manière à ce qu'un angle d'inclinaison (β) entre une direction (56a) de propagation de la lumière visible collimatée par un élément optique holographique (26a) associé avec un segment (20a) d'affichage déplacé d'une distance de déplacement (X) depuis un centre (58) de la pluralité de segments (20a, 20b) d'affichage et une direction (56b) de propagation de la lumière visible collimatée par un élément optique holographique (26b) associé avec un segment (20b) d'affichage situé au centre (58) de la pluralité de segments (20a, 20b) d'affichage augmente avec une augmentation de la distance de déplacement (X) de manière à ce que la lumière visible collimatée par chaque élément optique holographique (26a, 26b) passe à travers une pupille de sortie (60) du dispositif (10) d'affichage transparent monté sur la tête ou un casque.

10. Dispositif d'affichage transparent monté sur la tête ou un casque selon la revendication 9, comprenant :

- un cadre (64),

- un actionneur (66) pour incliner la pluralité de segments (20 ; 20a, 20b) d'affichage et la pluralité d'éléments optiques holographiques (26 ; 26a, 26b) par rapport au cadre (64),

- un dispositif (68) de capture d'image pour capturer une image d'une pupille (62) de l'œil (16) de l'utilisateur et pour générer un signal de position représentant une position de la pupille (62) de l'œil (16) de l'utilisateur, et

- un contrôleur (70) pour commander l'actionneur (66) sur la base du signal de position de manière à ce que la position de la pupille de sortie (60) du dispositif (10) d'affichage transparent monté sur la tête ou un casque coïncide avec la position de la pupille (62) de l'œil (16) de l'utilisateur.

11. Dispositif d'affichage transparent monté sur la tête ou un casque selon la revendication 9 ou 10, comprenant :

- un dispositif (78) de décalage pour décaler la pluralité de segments (20a, 20b) d'affichage par rapport à la pluralité d'éléments optiques holographiques (26a, 26b) le long des plans focaux des éléments optiques holographiques (26a, 26b),

- un dispositif de capture d'image (68') pour capturer une image d'une pupille (62) de l'œil (16) de l'utilisateur et pour générer un signal de position représentant une position de la pupille (62) de l'œil (16) de l'utilisateur, et

- un contrôleur (70') pour commander le dispositif (78) de décalage sur la base du signal de position de manière à ce que la position de la pupille de sortie (60) du dispositif (10) d'affichage transparent monté sur la tête ou un casque coïncide avec la position de la pupille (62) de l'œil (16) de l'utilisateur.

12. Dispositif d'affichage transparent monté sur la tête ou un casque selon l'une des revendications 1 à 11, comprenant :

un dilatateur (72) de faisceau pour dilater la lumière visible collimatée par les segments optiques holographiques (26 ; 26a, 26b), le dilatateur (72) de faisceau étant prévu à la fois sur un côté de la pluralité des segments optiques holographiques (26 ; 26a, 26b) faisant face vers l'œil (16) de l'utilisateur et un côté de la pluralité de segments (20 ; 20a, 20b) d'affichage faisant face vers l'œil (16) de l'utilisateur.

Drawing