Field of the Invention
[0001] The present invention relates to display units, and in particular to display units
for displaying two or more consecutively changing images to be viewed by a viewer.
Background of the Invention
[0002] Multi-image display devices of various kinds are known. Such devices are used for
advertisement, instructional purposes, providing directions, games and many other
uses. These devices usually contain prisms revolving about their axes, or alternatively,
devices projecting movies in a closed cycle. All such devices, however, require a
substantial amount of electrical power for their operation, hence requiring connection
to electrical mains. Furthermore, such devices are of necessity of a substantial size,
due to the relative complexity of the required drive means and other parts thereof.
[0003] The basic optical principle of displacing a complex lithographic print relative to
a lenticular lens array has been known from the prior art,
e.g., U.S. Patent 5,494,445, which discloses general know-how for alternatively displaying
several images. However, to date, this knowledge has not been properly utilized for
advertising purposes. There exists a need for a dynamic, multi-image display to be
used in shopping centers and other locations, which is capable of functioning independently
when affixed to walls or attached to shelves, and which will present information regarding
the products to be sold.
[0004] Such a display should be self-powered, namely, free of any connection to the mains.
It must have the ability to present high-resolution images at a wide range of viewing
angles, sometimes on both of its sides, for viewing by observers approaching from
different directions. Maintenance considerations require an operating period of at
least 3 to 4 months without battery replacement. The advertising messages must be
easily replaceable by an unskilled worker on site, without any difficulty. The display
unit should be cost-effective; in other words, its cost should not exceed the price
of the product(s) it promotes.
Summary of the Invention
[0005] It is therefore a broad object of the present invention to provide a simple, inexpensive
display unit based on optical principles, which is capable of consecutively displaying
several high-resolution images and does not require connection to electrical mains.
[0006] It is a further object of the present invention to provide a display unit for displaying
a multiplicity of small or large consecutively changing images, which is capable of
operating over an extended period of time and is powered by an independent power source.
[0007] It is another further object of the present invention to provide a cost-effective
advertising display in which the message to be projected is easily replaceable and
may be changed by an unskilled maintenance attendant having no technical background.
[0008] In accordance with the present invention, there is therefore provided a self-powered
display unit for displaying at least two consecutively changing images to be viewed
by a viewer, said unit comprising a housing, at least one wall portion of the housing
being made of an array of liner lenses having a lenticular front face and a flat rear
face; at least one displaceable, light-weight, substantially planar indicia carrier
disposed inside the housing at a distance from the rear face at most equalling the
focal length of the lenses, and a high efficiency, low energy consumption, battery-operated
DC drive means for periodically displacing the indicia carrier for a distance at least
equalling the distance between two adjacent lenses of the array.
[0009] The invention will now be described in connection with certain preferred embodiments
with reference to the following illustrative figures so that it may be more fully
understood.
[0010] With specific reference now to the figures in detail, it is stressed that the particulars
shown are by way of example and for purposes of illustrative discussion of the preferred
embodiments of the present invention only, and are presented in the cause of providing
what is believed to be the most useful and readily understood description of the principles
and conceptual aspects of the invention. In this regard, no attempt is made to show
structural details of the invention in more detail than is necessary for a fundamental
understanding of the invention, the description taken with the drawings making apparent
to those skilled in the art how the several forms of the invention may be embodied
in practice.
Brief Description of the Drawings
[0011]
- Fig. 1
- is a cross-sectional view of the unit according to the present invention;
- Fig. 2
- is a front view of an indicia carrier for displaying changing images in accordance
with the present invention;
- Fig. 3
- is a front view of the unit displaying the letter A;
- Fig. 4
- is a schematic side view of the drive means and an eccentric attached thereto;
- Fig. 5
- is a frontal, partially cross-sectional view of a display unit, incorporating and
showing in detail the drive means for actuating an eccentric similar to that of Fig.
4;
- Fig. 6
- is a cross-sectional view of a further embodiment of a display unit according to the
present invention;
- Fig. 7
- is a partial, frontal, cross-sectional view of the display unit and a fitting for
attaching it to a shelf;
- Figs. 8 and 9
- are frontal and cross-sectional views, respectively, of a display unit according to
the present invention and incorporating a clock;
- Figs. 10 and 11
- are frontal and cross-sectional views, respectively, of a further embodiment of a
display unit incorporating a clock;
- Fig. 11A
- is an enlarged detailed view of the encircled portion in Fig. 11;
- Fig. 12
- illustrates a cam producing a stepwise movement of the indicia carrier;
- Fig. 13
- is a schematic, cross-sectional view of an array of linear lenses having a cross-section
conforming with that of per se known Fresnel lenses;
- Fig. 14
- is a cross-sectional view of a display unit including the array of lenses shown in
Fig. 13, and
- Fig. 15
- is a cross-sectional view of a display unit in which the array of lenses shown in
Fig. 13 is an integral part of a hollow, extruded panel.
Detailed Description of Preferred Embodiments
[0012] With reference to Figs. 1-3, there is seen a display unit 2 for displaying two or
more consecutively changing images to be viewed by a viewer even without moving the
line of sight. Unit 2 is composed of a housing 4 having a front face 6, constituted
by an array of lenses 8. The lenses could be arranged to form a horizontally extending
linear array as seen in Fig. 1, or alternatively, can constitute an array of a honeycomb,
spherical, or other arrangement.
[0013] Located behind the stationary front face 6, there is movably disposed a light-weight
indicia carrier 10 in the form of a sheet or film on one or two of its surfaces, on
the surface(s) of which are printed indicia in a manne
r per se known,
e.g., from U.S. Patents 5,100,330 or 5,488,451, or by any other method. The optical principle
on which such methods are based is the ability to make visible each one of the multiple
images printed on the surface(s) of carrier 10, by a minimal displacement thereof
with respect to the array of lenses 8.
[0014] The indicia carrier 10 may be easily replaced with another, similar carrier by pulling
the carrier out of slot 11 and slipping in a replacement carrier. This can be accomplished
by any unskilled person.
[0015] As seen in Figs. 1 and 4, unit 2 further comprises a compartment 12 located at the
bottom part of housing 4, which compartment accommodates electrically powered drive
means 14 having an output axis 16. The details of construction of drive means 14 will
be described hereinafter. On output axis 16 there is mounted an eccentric 18, seen
to better advantage in Fig. 5, a limited portion of the periphery of which is arranged
to project into the chamber 20 within which indicia carrier 10 is located, thereby
causing the bottom edge 22 of the indicia carrier 10 to make contact with the bottom
of a groove 24 provided along the circumference 26 of eccentric 18. Carrier 10 is
freely supported within groove 24, but it is prevented from slipping off eccentric
18 when the latter rotates.
[0016] Referring now to Fig. 5, there is shown a front view of eccentric 18, on which, for
illustrative purposes, there are drawn the shorter radius
R1 and the longer radius
R2, the difference between which constitutes the displacement distance of indicia carrier
10. Optionally, eccentric 18 is furnished with a weight 28 disposed about the periphery
at smaller radius
R1 , the purpose of which weight is to counterbalance some of the indicia carrier's
weight upon its displacement in the upward direction.
[0017] A more detailed illustration of the invention is shown in Fig. 5, illustrating split
housing 4, indicia carrier 10, guides 30, 32 for guiding the movement of the indicia
carrier, and eccentric 18, on the circumference of which indicia carrier 10 rests.
Also shown is the high-efficiency, low energy consumption drive means 14 for rotating
eccentric 18, including electronic oscillator 34 powered by battery 36 and connected
to electromagnet 38 having two ferromagnetic arms 40, 42. Each of the free ends of
arms 40, 42 is configured as an armature 44, 46, surrounding but not contacting a
magnetic core 48, directly or indirectly coupled to transmission gears 50 52 for driving
eccentric 18. Each pulse emitted by the oscillator effects a 180° rotation of core
48. The eccentric's contour is such that its rotation is translated into a linear
displacement of the indicia carrier 10, which is freely supported on the grooved circumference
of the eccentric, as described above. The radii
R1 and
R2 of eccentric 18 are calculated such that the total linear displacement of indicia
carrier 10 in the upward and downward directions will be a distance at least equal
to the distance
D between two focal lines of two adjacent lenses located in the direction of displacement.
The displacement of indicia carrier 10 by such an amplitude will effect a consecutive
display of the images formed on the indicia carrier's surface. As indicia carrier
10 is of minimal weight, and in view of the efficient drive means described above,
which uses energy only during the relatively short duration of the pulse generated
by oscillator 34, the power required to operate the unit is also minimal; thus, the
unit can operate over extended periods of time without requiring a change of battery.
Naturally, the unit may also be powered or aided by solar cells.
[0018] While in Figs. 1-5 there is illustrated a unit displaying images on one side only,
Fig. 6 illustrates an embodiment in which the changing images are displayed on two
opposite sides of the unit. For achieving this, all that is required is to provide
a second array of lenses 8' on the other face of the unit and to provide images on
both surfaces of indicia carrier 10. Otherwise, the structure and operation of this
embodiment are the same as described above with reference to Figs. 1-5.
[0019] Fig. 7 illustrates a cross-sectional view of a split housing 4 formed with a suitable
opening 54 which engages fitting 56 for attaching unit 2 to a shelf,
e.g., a merchandise display shelf in a supermarket or department store. Fitting 56 is
designed to facilitate a flexible connection with unit 2 and a more rigid connection
to a shelf, to avoid breaking if the unit is accidentally bumped by a passing customer
or worker. The flexible connection between fitting 56 and unit 2 is achieved by means
of an arm 58 engaging the opening 54 and held therein by friction. The more rigid
connection is achieved by means of a metallic bracket 60.
[0020] Figs. 8-11 illustrate two embodiments for utilizing the display unit of the present
invention in conjunction with a clock. The first of these embodiments is illustrated
in Figs. 8 and 9, and shows a clock 62, operated by means of standard clock movement
64 disposed inside the housing 4 of unit 2, thus providing a combined clock and changing
display unit. Obviously, the clock of Fig. 8 can also be a digital clock. In the second
embodiment, illustrated in Figs. 10 and 11, the changing displays are positioned behind
the clock face. Such positioning facilitates both the operation of clock 62 and changing
of the displays on indicia carrier 10, by means of a common drive means 14.
[0021] As shown in Fig. 11
A, eccentric 18 is fixedly attached to and driven by the seconds shaft 15 of common
drive means 14 and moves inside a central hole 17 of suitable shape and size in carrier
10.
[0022] Fig. 12 shows an eccentric 28 or, more correctly, a cam, having three different radii
of curvature
r1,
r2,
r3, as well as ramps 29 leading from one curvature to the adjacent one. Also shown is
a cam follower in the form of a roller 66 mounted in a fork 67 fixedly attached to
indicia carrier 10. It is clear that when cam 28 rotates in the direction of arrow
A, the roller 66 will start rolling along curvature
r1. Since curvature
r1 is concentric with shaft 16, carrier 10 will remain stationary until roller 66, together
with carrier 10, are lifted onto the next curvature
r2 by the ramp 29, from which point the roller 66 will "dwell" again until it is lifted
once more by the next ramp 29 onto the next curvature
r3, at which point the indicia carrier 10 will have reached its maximum displacement.
Reaching the end of curvature
r3, roller 66 will drop onto curvature
r1, with carrier 10 again at its lowermost point. The cam thus has three "dwelling"
portions and three ramps, and will turn a uniform rotation of its shaft 16 into a
stepwise rise of indicia carrier 10. Such a cam is particularly useful for large display
units observed from considerable distances, where the line of sight does not greatly
deviate from the perpendicular relative to the unit.
[0023] The preparation of indicia carriers demands great accuracy, particularly in the dimensional
relationship of indicia parameters and the pitch of the array of the lenses. While
such accuracy is definitely achievable with small display units, it cannot possible
be realized with large units, because of inevitable cumulative errors in the preparation
of the indicia carrier, the effects of temperature fluctuations,
etc. Although in principle such problems could be alleviated by increasing the width
of the linear lenses of the array, such a step would have serious disadvantages of
its own:
1) As increasing the width of linear lenses, defined in cross-section by a circular
arc, automatically also increases the lens thickness, arrays of lenses of increased
width would be very heavy and, consequently, expensive.
2) The corrugated surfaces of the array produce highlights and glare, which interfere
with the visibility of the image. They are also prone to dust deposition.
[0024] A solution to the above problems is provided by the array of lenses depicted in Figs.
13 and 14. This array is constituted by co-planar, advantageously internal groups
of linear lenses having a cross-section conforming with that of the
per se known Fresnel lenses, each group consisting of a central, substantially cylindrical
lens, flanked by a number of quasi-prismatic linear lenses (quasi, because, strictly
speaking, the slanting surfaces of these prisms are parts of cylindrical surfaces).
Because of their large
f number [in the case of the linear Fresnel lens, focal length
f/width
m (Fig. 13)], this type of lens offers a relatively large width (e.g., 40 mm) combined
with a reasonably short focal length.
[0025] Fig. 13 is a schematic representation of a display unit using the above-mentioned
array of quasi-prismatic linear lenses. There is seen in Fig. 13 an indicia carrier
10, located at a distance
f behind an array 84 of the above-mentioned lenses. Array 84 is comprises of a plurality
of groups 86, each group consisting of a central, substantially cylindrical lens 88,
flanked by a plurality of linear, quasi-prismatic lenses 90. Advantageously, array
84 is one integral whole,
e.g., produced by extrusion or embossing, although it can also be built up from several
parts, particularly for large display units. As can be seen, the surface facing the
viewer is completely smooth and is far less subject to reflective and glare phenomena
and dust accretion.
[0026] Fig. 14 shows a display unit in which the array 84 of Fig. 13 is produced by extrusion
and is provided with ribs 92, which both stiffen array 84 and prevent indicia carrier
10 from bulging. Carrier 10 is moved up and down, as indicated by double arrow
B, by any of the previously described means. The display unit of Fig. 14 can also be
provided with a light source, such as a battery of fluorescent tubes 94.
[0027] The unit of Fig. 15 is similar to that of Fig. 14, except that array 84 constitutes
the front surface of a hollow, extruded panel, the rear surface 96 of which is connected
to array 84 by means of ribs 92. This embodiment is thus exceptionally rigid and is
therefore suitable for very large display units.
[0028] It will be evident to those skilled in the art that the invention is not limited
to the details of the foregoing illustrated embodiments and that the present invention
may be embodied in other specific forms without departing from the spirit or essential
attributes thereof. The present embodiments are therefore to be considered in all
respects as illustrative and not restrictive, the scope of the invention being indicated
by the appended claims rather than by the foregoing description, and all changes which
come within the meaning and range of equivalency of the claims are therefore intended
to be embraced therein.
1. A self-powered display unit for displaying at least two consecutively changing images
to be viewed by a viewer, said unit comprising:
a housing, at least one wall portion of said housing being made of an array of linear
lenses having a lenticular front face and a flat rear face;
at least one displaceable, light-weight, substantially planar indicia carrier disposed
inside said housing at a distance from said rear face at most equalling the focal
length of the lenses, and
a high efficiency, low energy consumption, battery-powered DC drive means for periodically
displacing said indicia carrier for a distance at least equalling the distance between
two adjacent lenses of said array.
2. The display unit as claimed in claim 1, wherein said indicia carrier is in the form
of a replaceable film or sheet.
3. The display unit as claimed in claim 1, wherein said drive means is motor coupled
to a cam means, an edge of said indicia carrier abutting against said cam means at
least indirectly, and the total rise of said cam means substantially equalling the
required displacement distance of said indicia carrier.
4. The display unit as claimed in claim 3, wherein said motor is an electric motor powered
by a solar cell arrangement.
5. The display unit as claimed in claim 3, wherein said motor is an impulse-driven stepping
motor having a shaft.
6. The display unit as claimed in claim 5, wherein each of said impulses rotates the
shaft of said stepping motor by 180°.
7. The display unit as claimed in claim 5, wherein said shaft rotates at a speed between
2 and 4 r.p.m.
8. The display unit as claimed in claim 4, wherein said cam means is an eccentric.
9. The display unit as claimed in claim 4, wherein said cam means is provided with a
peripherally disposed weight to counterbalance at least some of said indicia carrier's
weight upon its displacement in the upward direction.
10. The display unit as claimed in claim 1, wherein said indicia carrier is at least semi-transparent
so as to allow light to pass therethrough.
11. The display unit as claimed in claim 1, wherein said housing comprises two parallel,
spaced-apart wall portions, each made of an array of lenses, and said indicia carrier
comprises displayable indicia on both of its sides for simultaneously displaying images
on two sides of said unit.
12. The display unit as claimed in claim 1, wherein said housing further comprises means
for affixing the unit onto a shelf.
13. The display unit as claimed in claim 1, wherein said unit is in the form of a clock
with a changing clock face.
14. The display unit as claimed in claim 3, wherein said cam means is fixedly attached
to the seconds shaft of a standard clock drive.
15. The display unit as claimed in claim 1, wherein:
each of the lenses of said array is a linear lens of a cross-section conforming with
the cross-section of a Fresnel lens, and
said array of linear lenses constitutes the front wall of an extruded, hollow, two-sided
panel, the rear wall of said panel being connected to said front wall by a plurality
of ribs.