Light guide plate, display device, game machine, and in-vehicle display unit

Abstract

To provide a light guide plate which can clearly display a three-dimensional image nearly parallel to an incidence surface.SOLUTION: A light guide plate (10A) includes: an incidence surface (11a) in which light enters from a light source (20); an exit surface (11c) from which light exits; and a plurality of light deflection parts (12) for emitting light which entered from the incidence surface and was guided, from the exit surface. The light deflection parts are on arrangement lines (13) as linear arrangement regions and at least one of the arrangement lines is a composite intersection arrangement line (131).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a light guide plate, a display device, a gaming machine, and an in-vehicle display for displaying a stereoscopic image by parallax.

Background Art

[0002] Patent Document 1 discloses a light guide plate for displaying a stereoscopic image by parallax. The light guide plate includes a plurality of deflection portions having inclined surfaces that reflect light incident from a light source through an incident surface that is a side surface and guided while being totally reflected inside, and emit the light from an emission surface. The deflection portions are provided for each row parallel to the incident surface. The direction of the inclined surface of each row changes according to the distance from the incident surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, although details will be described later, in the light guide plate of Patent Document 1, in a region where a stereoscopic image that is nearly parallel to the incident surface is displayed, it is necessary to narrow the row spacing of the deflection portions for displaying the stereoscopic image. In such a region, there is a problem that the transparency of the light guide plate decreases due to the high density of the deflection portions. In addition, when it is desired to display a stereoscopic image with extremely high parallelism to the incident surface, there is also a problem that it becomes difficult to display the stereoscopic image as a continuous line image.

[0005] One aspect of the present disclosure aims to realize a light guide plate or the like that can clearly display a stereoscopic image that is nearly parallel to the incident surface.

Means for Solving the Problems

[0006] In order to solve the above problems, a light guide plate according to one aspect of the present invention is a light guide plate for displaying a stereoscopic image due to parallax, and includes an incident surface on which light from a light source is incident, an exit surface from which the light is emitted, and a plurality of light deflection units that deflect the light incident from the incident surface and guided and emit the light from the exit surface. The plurality of light deflection units are arranged on an array line that is a linear array region. A point on the exit surface that emits first emitted light deflected by the light deflection unit to an angular range irradiated to one eye of an observer observing the exit surface from within a predetermined range of an observation space and its vicinity is defined as a first emission point, and a point on the exit surface that emits second emitted light deflected by the light deflection unit to an angular range irradiated to the other eye of the observer and its vicinity is defined as a second emission point. A plurality of the light deflection units arranged on the array line are provided so that a straight line passing through the first emission point and the center of the one eye and a straight line passing through the second emission point and the center of the other eye intersect each other to form an intersection point. A plurality of the array lines are provided, and at least one of the array lines is a multi-intersection array line on which a plurality of the light deflection units are provided so as to form the intersection point at a plurality of positions for each position of the one eye and the other eye.

[0007] According to the above configuration, the light deflected by the light deflection units provided on the multi-intersection array line forms an intersection point at a plurality of positions for each position of one eye and the other eye of the observer. Therefore, for each position of one eye and the other eye of the observer, the light from the plurality of light deflection units provided on the multi-intersection array line is visually recognized. At this time, the observer visually recognizes the light as light within a region having a width in a direction along the multi-intersection array line. Therefore, a stereoscopic image that is nearly parallel to the incident surface can be clearly displayed.

[0008] Further, in the light guide plate according to one aspect of the present disclosure, each of the plurality of light deflection units has a light deflection surface that deflects the light, and the light deflection surface of the light deflection unit arranged on the multi-intersection array line is a curved surface in which the direction of deflecting the light emitted from one light source continuously changes from a first direction toward a first position in the observation space to a second direction toward a second position different from the first position.

[0009] According to the above configuration, an observer visually recognizes light from a plurality of light deflection units provided on the complex intersection array line as continuous light from a first direction to a second direction in a direction along the complex intersection array line. Therefore, a stereoscopic image that is continuous in the direction along the complex intersection array line can be clearly displayed.

[0010] Further, in the light guide plate according to one aspect of the present disclosure, the minimum value of the amount of light corresponding to the direction in which the light deflected by the light deflection unit disposed on the complex intersection array line is deflected is 0.7 times or more the maximum value of the amount of light.

[0011] According to the above configuration, a stereoscopic image that is continuous in the direction along the complex intersection array line can be recognized by an observer as an image with a substantially constant amount of light.

[0012] Further, in the light guide plate according to one aspect of the present disclosure, the average amount of light in the region of the outer peripheral portion of the stereoscopic image of the light deflected by the light deflection unit disposed on the complex intersection array line is 2 times or more the average amount of light in the region inside the region of the outer peripheral portion of the stereoscopic image of the light deflected by the light deflection unit disposed on the complex intersection array line.

[0013] According to the above configuration, the contour of the stereoscopic image can be emphasized.

[0014] Further, in the light guide plate according to one aspect of the present disclosure, the light deflection unit includes a first light deflection unit having a first curvature of the curved surface and a second light deflection unit having a second curvature different from the first curvature, and between a first light deflection region where the first light deflection unit is disposed and a second light deflection region where the second light deflection unit is disposed, an intermediate region is provided in which the first light deflection unit and the second light deflection unit are disposed in a randomly mixed state.

[0015] According to the above configuration, it becomes difficult for an observer to visually recognize a location where the curvature of the curved surface of the light deflection unit changes.

[0016] Further, in the light guide plate according to one aspect of the present disclosure, the amount of light deflected by each of the plurality of light deflection portions is constant for each of the complex intersection array lines on which the light deflection portions are arranged. When the intermediate value is the value between the maximum value and the minimum value of the amount of light deflected in the reference direction, which is the direction intermediate between the first direction and the second direction, by the light deflection portion, the minimum value is 0.7 times or more of the intermediate value, and the maximum value is 1.3 times or less of the intermediate value.

[0017] According to the above configuration, even when the width of the stereoscopic image is different for each complex intersection array line, it is visually recognized by the observer so that the amount of light is substantially constant.

[0018] Further, in the light guide plate according to one aspect of the present disclosure, each of the light deflection portions has a light deflection surface for deflecting the light, and the directions in which the light deflection surfaces of the plurality of light deflection portions arranged on the complex intersection array line deflect the light are dispersed between a first direction toward a first position in the observation space and a second direction toward a second position different from the first position.

[0019] According to the above configuration, the observer visually recognizes the light from the plurality of light deflection portions provided on the complex intersection array line as intermittent light between the first direction and the second direction in the direction along the complex intersection array line. Therefore, an intermittent stereoscopic image can be displayed between the first direction and the second direction in the direction along the complex intersection array line.

[0020] Further, in the light guide plate according to one aspect of the present disclosure, the directions in which the respective light deflection surfaces of the plurality of light deflection portions deflect the light are randomly dispersed between the first direction and the second direction.

[0021] According to the above configuration, an effect can be achieved in which it randomly flickers between the first direction and the second direction in response to a change in the observation position.

[0022] Further, in a plurality of light deflection portions of the light guide plate according to one aspect of the present disclosure, a first light deflection portion group which is a set of the light deflection portions that deflect the light in the first direction with respect to one eye and the other eye at an arbitrary position, a second light deflection portion group which is a set of the light deflection portions that deflect the light in the second direction with respect to one eye and the other eye at an arbitrary position, and a third light deflection portion group which is a set of the light deflection portions that deflect the light in a random direction between the first direction and the second direction are included.

[0023] According to the above configuration, regardless of the observation position, the light deflection portions included in the first light deflection portion group and the second light deflection portion group deflect the light in the first direction and the second direction. Further, the light deflection portions included in the third light deflection portion group deflect the light in a random direction corresponding to the observation position between the first direction and the second direction. Therefore, an effect can be achieved in which the outline is always displayed and the inside of the outline randomly flickers.

[0024] Further, in the light guide plate according to one aspect of the present disclosure, there is a positive correlation between the width of the stereoscopic image in a direction corresponding to the direction along the complex intersection array line and the number of the light deflection portions arranged along the complex intersection array line.

[0025] According to the above configuration, fluctuations in the amount of light caused by fluctuations in the width of the stereoscopic image can be reduced.

[0026] Further, a display device according to one aspect of the present disclosure includes the above light guide plate, a plurality of light sources that make light incident on the light guide plate from the incident surface, and a control unit that controls the plurality of light sources.

[0027] According to the above configuration, by the control unit controlling the plurality of light sources, the position of the light source that makes light incident on the light guide plate can be changed.

[0028] Further, in the display device according to one aspect of the present disclosure, the plurality of light sources may be linearly arranged, and the control unit may control the plurality of light sources to be sequentially turned on and off from one end to the other end of the linear region.

[0029] According to the above configuration, it is possible to realize control such that the position of the light source that makes light incident on the light guide plate moves from one end to the other end of the region where a plurality of light sources are linearly arranged.

[0030] Further, in the display device according to one aspect of the present disclosure, the plurality of light sources are linearly arranged, and the control unit may control the plurality of light sources to be sequentially turned on and off from an arbitrary point other than one end and the other end of the linear region to both one end and the other end.

[0031] According to the above configuration, it is possible to realize control such that the position of the light source that makes light incident on the light guide plate moves from both ends other than both ends of the region where a plurality of light sources are linearly arranged to both ends.

[0032] Further, a gaming machine according to one aspect of the present disclosure includes the above display device.

[0033] According to the above configuration, the same effects as those of the above display device are achieved.

[0034] Further, an in-vehicle display according to one aspect of the present disclosure includes the above display device.

[0035] According to the above configuration, the same effects as those of the above display device are achieved.

Effects of the Invention

[0036] According to one aspect of the present invention, it is possible to realize a light guide plate or the like that can clearly display a stereoscopic image that is nearly parallel to the incident surface.

Brief Description of the Drawings

[0037]

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Mode for Carrying Out the Invention

[0038] 〔Embodiment 1〕 Hereinafter, an embodiment of the present invention will be described in detail. In the following description, "A to B" indicating a numerical range means "A or more and B or less" unless otherwise noted. Also, in each drawing, when there are a plurality of elements to which the same reference numeral should be attached, the reference numeral may be attached to only a part of them.

[0039] (Application Example) FIG. 1 is a plan view showing the configuration of a display device 1A in one aspect of the present disclosure. First, with reference to FIG. 1, an example of a scene to which the present disclosure is applied will be described. As shown in FIG. 1, the display device 1A in the present disclosure includes a light guide plate 10A, a light source 20, and a control unit 30. For simplicity, the control unit 30 is omitted except in FIG. 1.

[0040] The light guide plate 10A displays a stereoscopic image SI due to parallax. In this application example, the light guide plate 10A has a rectangular plate shape in plan view. In other words, the light guide plate 10A has a cuboid shape. However, the shape of the light guide plate 10A is not limited to this. The material of the light guide plate 10A may be, for example, polycarbonate, acrylic, other resins having translucency, or glass.

[0041] The stereoscopic image SI includes one or more line segments or curves, etc. The stereoscopic image SI expresses characters, figures, or patterns, etc. by a combination of line segments or curves.

[0042] The light guide plate 10A has an incident surface 11a. The incident surface 11a is the surface on which the light from the light source 20 is incident on the light guide plate 10A. The incident surface 11a is one of the side surfaces of the light guide plate 10A having a rectangular parallelepiped shape. The side surface is the surface adjacent to the main surface when the largest area surface in the rectangular parallelepiped shape is referred to as the main surface.

[0043] Also, the light guide plate 10A has another side surface 11b facing the incident surface 11a. In the display device 1A, the light source 20 may also be arranged on the side surface 11b, and light may be incident on the light guide plate 10A from the side surface 11b.

[0044] Also, the light guide plate 10A has an exit surface 11c. The exit surface 11c is the surface from which the light guided inside the light guide plate 10A exits the light guide plate 10A. The exit surface 11c is one of the main surfaces of the light guide plate 10A having a rectangular parallelepiped shape.

[0045] Also, the light guide plate 10A has a plurality of light deflection portions 12. The light deflection portion 12 deflects the light incident from the incident surface 11a and guided inside the light guide plate 10A, and causes it to exit from the exit surface 11c. The light deflection portion 12 in the present embodiment is a V-groove structure extending in a direction corresponding to the position of the observation space with respect to the light guide plate 10A and the display position of the stereoscopic image SI, and a plurality of rows are formed side by side in the incident direction. In the drawings, for convenience of explanation, the number of the light deflection portions 12 formed on the light guide plate 10A is shown reduced from the actual number.

[0046] FIG. 2 is a cross-sectional view showing the path of the light guided by the light guide plate 10A. As shown in FIG. 2, the light deflection portion 12 is provided on the back surface 11d of the light guide plate. The back surface 11d is the other main surface of the light guide plate 10A having a rectangular parallelepiped shape and facing the exit surface 11c.

[0047] The light deflection unit 12 has an inclined surface 12a (light deflection surface) that reflects the light from the light source 20 incident from the incident surface 11a toward the emission surface 11c. In the present embodiment, in order to reflect the light L incident from the incident surface 11a, the light deflection unit 12 has an inclined surface 12a corresponding to the incident surface 11a. When light also enters from the side surface 11b, the light guide plate 10A further includes a light deflection unit 12 in which an inclined surface 12a corresponding to the light from the side surface 11b is formed. Further, the light deflection unit 12 may further have, separately from the inclined surface 12a, a surface for reflecting the light incident on the light deflection unit 12 from a direction other than the intended direction in a direction where the observer cannot recognize it.

[0048] In the light guide plate 10A, the light L incident from the incident surface 11a is guided while being totally reflected between the emission surface 11c and the back surface 11d. The light L incident on the light deflection unit 12 is reflected by the inclined surface 12a and enters the emission surface 11c at an incident angle smaller than the incident angle at which total reflection occurs at the emission surface 11c. As a result, the light L is emitted from the emission surface 11c. However, the deflection of the light by the light deflection unit 12 is not limited to that by reflection, and may be, for example, by refraction.

[0049] The size of the light deflection unit 12 may be, for example, 30 μm to 300 μm in a direction perpendicular to the incident direction of the light from the light source 20. Further, the angle of the inclined surface 12a with respect to the back surface 11d may be, for example, 30° to 60°. The shape of the light deflection unit 12 in a plan view seen from a direction perpendicular to the back surface 11d may be a rectangular shape such as a rectangle, or may be a spindle shape. Particularly in the latter case, the moldability of the light deflection unit 12 is improved as compared with the former shape and the like. However, the size and shape of the light deflection unit 12 are not limited to these.

[0050] FIG. 3 is a perspective view for explaining the directivity of the emitted light emitted from the emission surface 11c of the light guide plate 10A. FIG. 4 shows the principle of stereoscopic display based on parallax, and is a perspective view showing an intersection point where a straight line passing through the center of the first emission point P1 and one eye E1 of the observer intersects a straight line passing through the center of the second emission point P2 and the other eye E2 of the observer. For simplicity, only one light source 20 is shown in FIGS. 3 and 4.

[0051] Figure 3 shows a state in which an observer is observing the display device 1A from within an observation space of a predetermined range. The observation space is a space in which at least a part of the stereoscopic image SI displayed by the display device 1A can be observed.

[0052] The light emitted within the angular range irradiated on one eye E1 of the observer and its vicinity is referred to as first emitted light L1, and the point on the emission surface 11c from which the first emitted light L1 is emitted is referred to as first emission point P1. Further, the light emitted within the angular range irradiated on the other eye E2 of the same observer and its vicinity is referred to as second emitted light L2, and the point on the emission surface 11c from which the second emitted light L2 is emitted is referred to as second emission point P2.

[0053] The first emitted light L1 emitted from the first emission point P1 is visually recognized by one eye E1 of the observer. On the other hand, the first emitted light L1 is not visually recognized by the other eye E2, or the amount of light visually recognized by the other eye E2 is extremely small compared to the amount of light visually recognized by one eye E1. As a result, the first emitted light L1 has directivity.

[0054] Also, the second emitted light L2 from the second emission point P2 is visually recognized by the other eye E2 of the observer. On the other hand, the second emitted light L2 is not visually recognized by one eye E1, or the amount of light visually recognized by one eye E1 is extremely small compared to the amount of light visually recognized by the other eye E2. As a result, the second emitted light L2 has directivity.

[0055] As shown in Figure 4, the straight line passing through the center of the first emission point P1 and one eye E1, that is, the pupil and the lens, and the straight line passing through the center of the second emission point P2 and the other eye E2 intersect at an intersection point C. In other words, the optical axis of the first emitted light L1 visually recognized by one eye E1 of the observer and the optical axis of the second emitted light L2 visually recognized by the other eye E2 of the observer intersect at the intersection point C. Therefore, the observer has an illusion that a light-emitting point exists at the intersection point C.

[0056] When the intersection point C is located on the observer side with respect to the exit surface 11c, the light-emitting point appears to the observer to jump out from the exit surface 11c. On the other hand, when the intersection point C is located on the side opposite to the observer with respect to the exit surface 11c, the light-emitting point appears to the observer to be on the back side of the exit surface 11c. In the present embodiment, the intersection point C is located on the back side of the exit surface 11c as viewed from the observer. For this reason, the observer will perceive a sense of depth.

[0057] In this way, when the first emitted light L1 is emitted within an angular range directed toward one eye E1 of the observer and its vicinity, and the second emitted light L2 is emitted within an angular range directed toward the other eye E2 of the same observer and its vicinity, and the optical axis of the first emitted light L1 and the optical axis of the second emitted light L2 have an intersection point C, the observer has an illusion that a light-emitting point exists at the intersection point C. Therefore, by forming such an intersection point C as a set of continuous points so as to be a plurality of intersection points C1, C2,... the observer can perceive, for example, a three-dimensional stereoscopic image SI in the form of a straight line.

[0058] The light source 20 is a light-emitting element that causes light to enter the light guide plate 10A. The light source 20 may be a point light source. Examples of the light source 20 include an LED (Light Emitting Diode) or an LD (Laser Diode). However, the light source 20 is not limited to this, and other light sources such as a fluorescent lamp may be used. Also, in FIG. 1, the display device 1A includes one light source 20. However, the display device 1A may include a plurality of light sources 20. The plurality of light sources 20 may be arranged, for example, at intervals of 10 mm, but the interval between the light sources 20 is not limited to this.

[0059] Also, as described above, the shape of the light guide plate 10A is not limited to the above-described rectangular parallelepiped shape. For example, the light guide plate 10A may have a shape in which a part of the region in a plan view when viewed from a direction perpendicular to the exit surface 11c is cut out in a rectangular shape, so that the incident surface 11a is not flush and has a step. In this case, the light source 20 may be arranged along each of the non-flush incident surfaces 11a.

[0060] The control unit 30 controls the lighting and extinguishing of the light source 20. When there are a plurality of light sources 20, the control unit 30 may control their lighting and extinguishing individually.

[0061] In particular, when a plurality of light sources 20 are arranged linearly, the control unit 30 may control the plurality of light sources 20 to be sequentially lit and extinguished from one end to the other end of the line. Thereby, an effect can be produced as if the stereoscopic image SI moves from one end side to the other end side of the linearly arranged light sources 20.

[0062] Also, when a plurality of light sources 20 are arranged linearly, the control unit 30 may control the plurality of light sources 20 to be sequentially lit and extinguished from an arbitrary point other than one end and the other end of the line to both ends. For example, the control unit 30 may control the plurality of light sources 20 to be symmetrically and sequentially lit and extinguished from the center of the line to both ends. Thereby, an effect can be produced as if the stereoscopic image SI is divided and moves from the center of the linearly arranged light sources 20 to both the one end side and the other end side.

[0063] Also, the light source 20 may be a so-called RGB LED whose light color can be adjusted. In this case, the control unit 30 may control the color of the light emitted by the light source 20. The control unit 30 can realize an effective effect, for example, by making the light colors of adjacent light sources 20 different from each other.

[0064] Also, the control unit 30 can realize an even more impactful effect by color mixing by superimposing a plurality of stereoscopic images of different colors. For example, by superimposing a stereoscopic image of (R, G, B) = (255, 0, 0) and a stereoscopic image of (R, G, B) = (0, 255, 255), the overlapping part can be made (R, G, B) = (255, 255, 255), that is, white. Also, the control unit 30 may superimpose three or more stereoscopic images.

[0065] (Configuration example) FIG. 5 is a perspective view showing a gaming machine 100 provided with the display device 1A of the present embodiment. As shown in FIG. 5, for example, in a pachinko machine or a pachislot machine as the gaming machine 100, a display device 1A is provided. The display device 1A is disposed near the central portion of the gaming machine 100. The display device 1A is configured to perform image display for various effects, such as an effect image indicating a big win or an effect image indicating the expectancy of a big win. Specifically, the display device 1A is configured to stereoscopically display a stereoscopic image SI as an image display. Controls such as control over whether to display the stereoscopic image SI, control over switching the light source 20 to be lit at a predetermined timing, or control over switching a plurality of light sources 20 that emit different colors from each other at a predetermined timing are performed by the control unit 30.

[0066] Note that the gaming machine 100 is merely one example of the application of the display device 1A of the present embodiment and does not limit the application range of the display device 1A. The display device 1A of the present embodiment may be applied to any object having a function of displaying an image. Another example of an object to which the display device 1A is applied is an in-vehicle display.

[0067] As shown in FIG. 1, in the display device 1A, the light deflection unit 12 is disposed on the array line 13. The array line 13 is a linear array region provided in plurality on the light guide plate 10A. In FIG. 1, the array lines 13 are a plurality of straight lines parallel to each other. However, the shape of the array line 13 is not limited to this. Another example of the shape of the array line 13 will be described later.

[0068] In the light guide plate 10A, the array line 13 includes a multi-intersection array line 131. In the multi-intersection array line 131, the light deflection unit 12 is provided so as to form intersections C at a plurality of positions for each position of the above-described one eye E1 and the other eye E2 in the observation space. Thereby, in the light guide plate 10A, a portion of the stereoscopic image SI that is nearly parallel to the incident surface 11a can be clearly displayed, and the transparency in the vicinity of the multi-intersection array line 131 can be maintained.

[0069] FIG. 6 is a diagram for explaining light deflected by the light deflection unit 12 on the multiple intersection array line 131. As shown in FIG. 6, light from the light source 20 is deflected by the light deflection unit 12 on the multiple intersection array line 131 and enters one eye E1 and the other eye E2 of the observer. By forming intersections C at a plurality of positions for each position of the light deflection unit 12 in the observation space, the observer has an illusion that the region CS as a set of intersections C formed at a plurality of positions, rather than a single intersection C, is the light emitting region.

[0070] (Arrangement of Light Deflection Unit) FIG. 7 is a diagram showing a specific example of the arrangement of the light deflection unit 12 in the light guide plate 10A. In FIG. 7, reference numerals 701 and 702 indicate different specific examples. In any of the specific examples, a matrix 14 is defined for the region where the light deflection unit 12 is arranged, and the light deflection unit 12 is arranged within the matrix 14.

[0071] In the example shown by reference numeral 701, the matrix 14 is arranged along a direction parallel to the incident surface 11a and a direction perpendicular to the incident surface 11a. Also, the array line 13 is inclined with respect to the direction parallel to the incident surface 11a. Therefore, the array line 13 is inclined with respect to the direction in which the matrix 14 is arranged. In this case, by arranging the light deflection unit 12 only in the matrix 14 located on the array line 13, the light deflection unit 12 can be arranged along the multiple intersection array line 131.

[0072] In the example shown by reference numeral 702, the matrix 14 is arranged along the array line 13. In this case, by arranging the light deflection unit 12 in any matrix 14, the light deflection unit 12 can be arranged along the array line 13.

[0073] FIG. 8 is a diagram showing a more specific example of the arrangement of the light deflection unit 12 in the light guide plate 10A. In FIG. 8, reference numerals 801 and 802 indicate different examples. FIG. 8 shows an example when displaying an image of the letter "A". In FIG. 8, the three-dimensional image SI, which is an image of the letter "A", is divided into two three-dimensional images SI1 and SI2 with slashes and one three-dimensional image SI3 with a horizontal line.

[0074] In the example shown by reference numeral 801, as the light deflection unit 12, a light deflection unit 121 for displaying the three-dimensional image SI1 with slashes, a light deflection unit 122 for displaying the three-dimensional image SI2 with slashes, and a light deflection unit 123 for displaying the three-dimensional image SI3 with a horizontal line are shown. The light deflection units 121 and 122 may be arranged in different matrices 14 on the array line 13, respectively. Also, the light deflection unit 123 may be arranged in a further different matrix 14 in parallel with the array line 13.

[0075] Also, the light deflection unit 12 may display two or more of the three-dimensional images SI1 and SI2 with slashes and the three-dimensional image SI3 with a horizontal line. In the example shown by reference numeral 802, as the light deflection unit 12, a light deflection unit 124 for displaying the three-dimensional images SI1 and SI2 with slashes and the three-dimensional image SI3 with a horizontal line, and a light deflection unit 125 for displaying the three-dimensional images SI1 and SI2 with slashes are shown. The light deflection units 124 and 125 may be arranged in different matrices 14 on the array line 13, respectively.

[0076] When the shape of the light deflection unit 12 is constant, there may be variations in the transparency of the light guide plate 10A due to the density of the light deflection unit 12. To reduce such variations, the shape etc. of the light deflection unit 12 may be appropriately changed. Alternatively, dummy light deflection units 12 that are not related to the display of the three-dimensional image SI may be arranged in regions where the density of the light deflection unit 12 is low.

[0077] (Shape of a light deflection unit in which the amount of light to be deflected is substantially uniform) FIG. 9 is a diagram showing a specific example of the shape of the light deflector 12 disposed on the multi-intersection array line 131. In FIG. 9, reference numerals 901 to 904 indicate different examples of the shape of the light deflector 12. In particular, in the example shown by reference numeral 901, a set of a plurality of partial light deflectors 126 constitutes one light deflector 12.

[0078] As shown in FIG. 9, in this configuration example, the inclined surface 12a of the light deflector 12 disposed on the multi-intersection array line 131 is a curved surface. The direction in which the curved surface deflects the light L emitted from the light source 20 continuously changes from a first direction toward a first position in the observation space to a second direction toward a second position different from the first position. For this reason, the observer can visually recognize the light deflected by the light deflector 12 from any position from the first position to the second position. In other words, at the same observation position, the observer can visually recognize the light deflector 12 from the light deflector 12 having the first position as the observation position to the light deflector 12 having the second position.

[0079] The light deflector 12 preferably has a shape in which the length in the direction perpendicular to the incident surface 11a is shorter at the end than at the center in the direction parallel to the incident surface 11a in a plan view from a direction perpendicular to the back surface 11d. Thereby, the moldability of the light deflector 12 is improved.

[0080] FIG. 10 is a diagram showing an example of a stereoscopic image displayed by the light deflector 12 shown in FIG. 9. In FIG. 10, the stereoscopic image displayed by the light deflector 12 is circular. Reference numeral 1001 indicates an example of an actually displayed stereoscopic image. Reference numeral 1002 is a graph showing the distribution of the light quantity of the light deflected by the light deflector 12 that deflects light on the axis AX parallel to the incident surface 11a of the stereoscopic image shown by reference numeral 1001. In reference numeral 1002, the horizontal axis is the angle of the light deflected by the light deflector 12 with respect to the direction perpendicular to the back surface 11d, and the vertical axis is the light quantity.

[0081] As shown in FIG. 10, in the stereoscopic image displayed by the light deflection unit 12 shown in FIG. 9, the amount of light can be regarded as substantially constant regardless of the position. Specifically, the minimum value of the amount of light of the light deflected by the light deflection unit 12 disposed on the multiple intersection array line 131 is 0.7 times or more the maximum value of the amount of light in the direction in which the light is deflected.

[0082] Generally, in a stereoscopic image, if the minimum value of the amount of light is 0.7 times or more the maximum value, it is visually recognized by the observer as if the amount of light is substantially constant. Therefore, according to such a light deflection unit 12, a stereoscopic image that is parallel to the incident surface 11a and whose amount of light can be regarded as substantially constant can be displayed. In particular, the minimum value of the amount of light may be 0.8 times or more the maximum value. In this case, the uniformity of the amount of light in the stereoscopic image is further improved.

[0083] (Shape of the light deflection unit where the amount of light at the end of the deflected light is higher than the amount of light at the center) FIG. 11 is a diagram showing another specific example of the shape of the light deflection unit 12 different from that shown in FIG. 9. In FIG. 11, reference numerals 1101 and 1102 indicate different examples of the shape of the light deflection unit 12. In the examples shown by reference numerals 1101 and 1102 in FIG. 11, the light deflection unit 12 is a collection of a partial light deflection unit 126 in which the inclined surface 12a is a curved surface and partial light deflection units 127 disposed on both sides of the partial light deflection unit 126 in which the inclined surface 12a is a flat surface. The partial light deflection unit 127 may be disposed at a distance from the partial light deflection unit 126 as shown by reference numeral 1101, or may be disposed in contact with the partial light deflection unit 126 as shown by reference numeral 1102.

[0084] FIG. 12 is a diagram showing an example of a stereoscopic image displayed by the light deflection unit 12 shown in FIG. 11. In FIG. 12, the stereoscopic image displayed by the light deflection unit 12 is circular. Reference numeral 1201 indicates an example of an actually displayed stereoscopic image. Reference numeral 1202 is a graph showing the distribution of the amount of light of the light deflected by the light deflection unit 12 that deflects light on the axis AX parallel to the incident surface 11a of the stereoscopic image shown by reference numeral 1201. In reference numeral 1202, the horizontal axis is the angle at which the light is deflected, and the vertical axis is the amount of light.

[0085] In the light deflecting unit 12 shown in FIG. 11, the area of the inclined surface 12a that deflects light in the first direction and the area of the inclined surface 12a that deflects light in the second direction are larger than the area of the inclined surface 12a that deflects light in other directions. Therefore, as shown in FIG. 12, in the stereoscopic image displayed by the light deflecting unit 12 shown in FIG. 11, the amount of light in the outer peripheral portion is larger than the amount of light in the inner side. The width of the outer peripheral portion of the stereoscopic image is not particularly limited, and it is sufficient that the amount of light in the region including the end portion of the stereoscopic image is larger than the amount of light in at least a part of the inner side of the region.

[0086] Since the amount of light in the outer peripheral portion of the stereoscopic image is larger than the amount of light in the inner side, a stereoscopic image with a clear contour can be displayed. Therefore, even if the amount of light in the inner side of the stereoscopic image is small, a decrease in the quality of the entire stereoscopic image can be prevented.

[0087] Specifically, the average of the amount of light in the region of the outer peripheral portion of the stereoscopic image of the light deflected by the light deflecting unit 12 disposed on the cross intersection array line 131 is at least twice the average of the amount of light in the region inside the region of the outer peripheral portion of the stereoscopic image of the light deflected by the light deflecting unit 12 disposed on the cross intersection array line 131. According to such a light deflecting unit 12, a stereoscopic image with particularly clear contours can be displayed.

[0088] In the example shown in FIG. 12, the light deflected by the partial light deflecting unit 126 constitutes the entire stereoscopic image. On the other hand, the light deflected by the partial light deflecting unit 127 constitutes only the outer peripheral portion of the stereoscopic image. That is, the outer peripheral portion of the stereoscopic image is composed of light from both the partial light deflecting units 126 and 127. On the other hand, the inside of the stereoscopic image is composed of only the light from the partial light deflecting unit 126. As a result, the amount of light in the outer peripheral portion of the stereoscopic image becomes larger than the amount of light in the inner side.

[0089] In the examples shown in FIGS. 9 and 11, the directivity of the light deflected by the light deflecting unit 12 is symmetric in the direction along the cross intersection array line 131. However, the directivity of the light deflected by the light deflecting unit 12 does not have to be symmetric in the direction along the cross intersection array line 131.

[0090] (Light directivity by the light deflection section) FIG. 13 is a diagram for explaining the light directivity by the light deflection section 12. Reference numeral 1301 is a plan view showing an example of the shape of the light deflection section 12. In the example shown by reference numeral 1301, in a plan view from a direction perpendicular to the back surface 11d, the angle formed by the inclined surface 12a of the light deflection section 12 and the plane parallel to the incident surface 11a is in the range of -30° to 30°.

[0091] Reference numeral 1302 is a graph showing the relationship between the angle formed by the inclined surface 12a of the light deflection section 12 having the shape shown by reference numeral 1301 and the plane parallel to the incident surface 11a, and the ratio (area ratio) of the area of the inclined surface 12a having the angle to the total area of the inclined surface 12a. In the graph of reference numeral 1302, the horizontal axis is the angle formed by the inclined surface 12a and the plane parallel to the incident surface 11a, and the vertical axis is the area ratio.

[0092] For example, in the light deflection section 12 having the shape shown by reference numeral 1301, the width of the inclined surface 12a in the light incident direction is 10 μm at the center and 5 μm at the end in the direction perpendicular to the light incident direction. In the graph shown by reference numeral 1302, when the area ratio at θ = 0° is set to 1, the area ratio at θ = 0° is about 0.5. This is because the width at the end is half of the width at the center in the direction perpendicular to the light incident direction of the inclined surface 12a in the light incident direction where θ = 0°.

[0093] Reference numeral 1303 is a diagram showing another example of the shape of the light deflection section 12 different from that shown by reference numeral 1301. In the example shown by reference numeral 1303, the inclined surface 12a has an inclined surface 12aa and inclined surfaces 12ab located on both sides thereof. The inclined surface 12aa is the same curved surface as the inclined surface 12a in the example shown by reference numeral 1301. The inclined surface 12ab is a plane having the same inclination as the end of the inclined surface 12aa. Therefore, the inclined surface 12ab deflects light in the same direction as the direction in which light is deflected by the end of the inclined surface 12aa.

[0094] Reference numeral 1304 is a graph showing the relationship between the angle formed by the inclined surface 12a and the plane parallel to the incident surface 11a in the light deflection section 12 having the shape shown by reference numeral 1303, and the area ratio of the inclined surface 12a having that angle. In the graph of reference numeral 1304, the horizontal axis represents the angle formed by the inclined surface 12a and the plane parallel to the incident surface 11a, and the vertical axis represents the area ratio.

[0095] In reference numeral 1304, it is assumed that the angle formed by the inclined surface 12a of the light deflection section 12 and the plane parallel to the incident surface 11a is in the range of -40° to 40°. The angle formed by the inclined surface 12a and the plane parallel to the incident surface 11a in the inclined surface 12ab is -40° or 40°. Therefore, in the range of -40° < θ < 40°, similar to the graph of reference numeral 1302, the area ratio is the largest at θ = 0° and decreases as it moves away from θ = 0°. On the other hand, the area ratios at θ = -40° and θ = 40° are significantly larger compared to the area ratios at other angles. For this reason, in the graph of reference numeral 1304, the variation in the area ratio is small in the range of -40° < θ < 40°, and the graph is substantially flat.

[0096] For example, consider the light deflection section 12 under the following conditions. · The material of the light guide plate 10A is polycarbonate with a refractive index of 1.59. · The angle of the inclined surface 12a with respect to the back surface 11d is 50°. · In a plan view from a direction perpendicular to the back surface 11d, the angle formed by the inclined surface 12a and the plane parallel to the incident surface 11a is in the range of -10° to 10°. · Within the range of the angle by which the light is deflected by the light deflection section 12, the amount of deflected light is uniform. At this time, the light deflected by the light deflection section 12 was distributed in the range of -16° to 16°.

[0097] (Light deflection section in which the deflected light exhibits gradation or tone expression) FIG. 14 is a diagram showing a specific example of the shape of the light deflection unit 12 different from those shown in FIGS. 10 and 12. In FIG. 14, reference numerals 1401 and 1402 denote different examples of the shape of the light deflection unit 12. In the examples shown by reference numerals 1401 and 1402 in FIG. 14, the light deflection unit 12 is a collection of a plurality of partial light deflection units 126. The size and shape of each partial light deflection unit 126 are not limited to those shown in FIG. 14 and may be determined as appropriate.

[0098] FIG. 15 is a diagram showing an example of a stereoscopic image displayed by the light deflection unit 12 shown in FIG. 14. In FIG. 15, the stereoscopic image displayed by the light deflection unit 12 is circular. Reference numeral 1501 denotes an example of a stereoscopic image actually displayed by the light deflection unit 12 shown by reference numeral 1401 in FIG. 14. Reference numeral 1502 is a graph showing the distribution of the amount of light deflected by the light deflection unit 12 that deflects light on the axis AX parallel to the incident surface 11a of the stereoscopic image shown by reference numeral 1501. Reference numeral 1503 denotes an example of a stereoscopic image actually displayed by the light deflection unit 12 shown by reference numeral 1402 in FIG. 14. Reference numeral 1504 is a graph showing the distribution of the amount of light deflected by the light deflection unit 12 that deflects light on the axis AX parallel to the incident surface 11a of the stereoscopic image shown by reference numeral 1503. In reference numerals 1502 and 1504, the horizontal axis represents the angle at which the light is deflected, and the vertical axis represents the amount of light.

[0099] As shown by reference numerals 1501 and 1502, in the stereoscopic image displayed by the light deflection unit 12 shown by reference numeral 1401 in FIG. 14, a gradation is presented in which the amount of light gradually decreases from the center toward the outer peripheral portion. Thereby, a stereoscopic image such as a neon sign in which the end portion of the image glows faintly can be displayed.

[0100] As shown by reference numerals 1503 and 1504, in the stereoscopic image displayed by the light deflection unit 12 shown by reference numeral 1402 in FIG. 14, there is a region where the amount of light is large as another region in the central portion in the direction parallel to the incident surface 11a. That is, the stereoscopic image is a two-tone image. Depending on the size and shape of the partial light deflection units 126 included in the light deflection unit 12, a stereoscopic image as shown by reference numerals 1503 and 1504 can also be displayed.

[0101] (Light deflecting part resistant to shape collapse) FIG. 16 is a diagram for explaining still another example of the shape of the light deflecting part 12. In FIG. 16, reference numeral 1601 is a plan view of the light deflecting part 12 as viewed from a direction perpendicular to the back surface 11d. In reference numeral 1601, unlike in FIG. 1 etc., it is assumed that light enters the light deflecting part 12 from the upper side in the drawing plane. In reference numeral 1601, the light deflecting part 12 has a shape symmetric with respect to the symmetry axis perpendicular to the incident surface 11a. Hereinafter, only one side of the light deflecting part 12 with respect to the symmetry axis will be described.

[0102] Let the direction parallel to the incident surface 11a be the X direction, the symmetry axis be X = 0, and the distance in the X direction from the symmetry axis of the light deflecting part 12 to the end be D. At X = 0, the inclination of the inclined surface 12a is 0. In the range of 0 ≦ X < D / 2, as the distance from the symmetry axis increases, the inclination of the inclined surface 12a increases. In the range of D / 2 ≦ X ≦ D, as the distance from the symmetry axis increases, the inclination of the inclined surface 12a decreases. At X = D, the inclination of the inclined surface 12a returns to 0. That is, the point at X = D / 2 on the inclined surface 12a is the inflection point of the inclination of the inclined surface 12a. At this time, the region of the inclined surface 12a in the range of 0 ≦ X ≦ D is point-symmetric with respect to the inflection point.

[0103] In FIG. 16, reference numeral 1602 is a graph showing the angle and light amount for each position of the light deflected by the light deflecting part 12 shown in reference numeral 1601. In reference numeral 1602, the horizontal axis is the position in the X direction, and the vertical axis is the angle or the light amount. In reference numeral 1602, the line graph shows the angle, and the bar graph shows the light amount. In reference numeral 1602, points where the angle by which the light is deflected is θA, θB, θC, or θD are shown.

[0104] As shown by reference numeral 1602, in the light deflection unit 12 shown by reference numeral 1601, for each of θA to θD, there are two locations, one on each side of the inflection point, where light is deflected at the same angle. For angles other than θA to θD, there are also two locations where light is deflected in the same direction. The amount of light changed to a certain angle is the sum of the amounts of light deflected at the two locations of the light deflection unit 12. Also, since the width of the inclined surface 12a in the direction perpendicular to the X direction narrows as it separates from X = 0, the amount of light deflected at X = 0 with respect to the inflection point is larger than the amount of light deflected on the X = D side. Therefore, even if the shape of the end portion of the light deflection unit 12 collapses near X = D due to a defect in the molding of the light deflection unit 12 or the like, the variation in the amount of light becomes small. In other words, the inclined surface 12a may not be completely point-symmetric with respect to the inflection point due to the collapse of the shape of the end portion.

[0105] In the example shown in FIG. 16, the shape of the inclined surface 12a can be appropriately changed according to the three-dimensional image to be displayed. For example, by making the area of the inclined surface 12a constant for each angle, a three-dimensional image with a uniform amount of light as shown in FIG. 16 can be displayed. Also, by widening the area of the inclined surface 12a at a specific angle, the amount of light in the region of the three-dimensional image corresponding to that angle can be increased. For example, by widening the region near the inflection point of the inclined surface 12a, a three-dimensional image with enhanced contours as shown in FIG. 16 can be displayed.

[0106] In the example shown by reference numeral 1601, the inclination of the inclined surface 12a with respect to the incident surface 11a is small near X = 0, increases as it approaches X = D / 2, and decreases as it approaches X = D beyond X = D / 2. That is, the inclination of the inclined surface 12a with respect to the incident surface 11a changes as small ⇒ large ⇒ small. However, the inclination of the inclined surface 12a with respect to the incident surface 11a may change in the reverse order of large ⇒ small ⇒ large. Even in this case, since there are two locations where light is deflected in the same direction on both sides of the inflection point, even if the shape collapses due to a defect in the molding of the light deflection unit 12 or the like near X = D, the variation in the amount of light becomes small.

[0107] However, in this case, the inclination of the inclined surface 12a on the positive side of X and the inclination of the inclined surface 12a on the negative side of X are reversed at X = 0. For this reason, the inclined surface 12a has a protruding shape in the vicinity of X = 0, and the shape of the inclined surface 12a is likely to collapse.

[0108] (Modification 1) FIG. 17 is a diagram for explaining the light deflection unit 12 according to the first modification of the first embodiment. In the example shown in FIG. 17, the light guide plate 10A displays strip-shaped stereoscopic images SI4 to SI6 perpendicular to the incident surface 11a. The stereoscopic image SI4 is displayed by the light deflection unit 12 located near the center in the X direction on the light guide plate 10A. The stereoscopic image SI5 is displayed by each of the light deflection units 12 located on both sides of the light deflection unit 12 that displays the stereoscopic image SI4. The stereoscopic image SI6 is displayed by each of the light deflection units 12 located on the side opposite to the light deflection unit 12 that displays the stereoscopic image SI4 of the light deflection unit 12 that displays the stereoscopic image SI5.

[0109] The curvature of the light deflection unit 12 that displays the stereoscopic image SI5 is larger than the curvature of the light deflection unit 12 that displays the stereoscopic image SI6. Also, the curvature of the light deflection unit 12 that displays the stereoscopic image SI4 is even larger than the curvature of the light deflection unit 12 that displays the stereoscopic image SI5. The larger the curvature of the light deflection unit 12, the larger the width of the angle by which the light deflection unit 12 deflects light. For example, for the light deflection unit 12 that displays the stereoscopic image SI6, the width of the angle by which light is deflected is set to 0°. Also, for the light deflection unit 12 that displays the stereoscopic image SI4, the width of the angle by which light is deflected is set to 10°. Also, for the light deflection unit 12 that displays the stereoscopic image SI5, the width of the angle by which light is deflected is set to be larger than 0° and less than 10°.

[0110] The wider the range of the angle by which the light deflection unit 12 deflects light, the wider the width of the stereoscopic image displayed by the light deflection unit 12 in the X direction. Therefore, among the stereoscopic images SI4 to SI6, the width of the stereoscopic image SI4 is the widest, the width of the stereoscopic image SI6 is the narrowest, and the width of the stereoscopic image SI5 is between them. As a result, a sense of depth can be created such that the stereoscopic image SI4 is positioned in the foreground and the stereoscopic images SI5 and SI6 are successively positioned farther away from the stereoscopic image SI1.

[0111] (Modification Example 2) FIG. 18 is a diagram for explaining the light deflection unit 12 according to the second modification example of Embodiment 1. In FIG. 18, reference numeral 1801 is an overall view of the light guide plate 10A. In the example shown by reference numeral 1801, the stereoscopic image SI displayed by the light guide plate 10A is a rectangular image whose four sides are inclined with respect to the incident surface 11a. When displaying such a stereoscopic image SI, it is necessary to vary the curvature of the light deflection unit 12 according to the width of the stereoscopic image SI in the direction along the multiple intersection array line 131.

[0112] In the following description, the curvature of the light deflection unit 12 included in the light guide plate 10B is defined by the angular range formed by the inclined surface 12a and the multiple intersection array line 131. Specifically, the light deflection unit 12 in which the angular range formed by the inclined surface 12a and the multiple intersection array line 131 is -n° to n° is defined as the light deflection unit 12 of θn. For example, the light deflection unit 12 in which the angular range formed by the inclined surface 12a and the multiple intersection array line 131 is -1° to 1° is the light deflection unit 12 of θ1.

[0113] Reference numeral 1802 is an enlarged view of a part of the back surface 11d of the light guide plate 10A in a comparative example. In reference numeral 1802, a first light deflection unit 128 having a first curvature and a second light deflection unit 129 having a second curvature different from the first curvature appear. In the comparative example, a first light deflection region R1 in which the first light deflection unit 128 is arranged and a second light deflection region R2 in which the second light deflection unit 129 is arranged are in contact with each other at the boundary line BL.

[0114] Reference numeral 1803 is an enlarged view of an end portion of the stereoscopic image SI when the first light deflection unit 128 and the second light deflection unit 129 are arranged as shown by reference numeral 1802. When the first light deflection unit 128 and the second light deflection unit 129 are arranged as shown by reference numeral 1802, since the light amount is switched at the boundary line BL between the first light deflection region R1 and the second light deflection region R2, a line corresponding to the boundary line BL may be visually recognized by the observer. In particular, at the end portion of the stereoscopic image SI, as shown by reference numeral 1803, the boundary line BL between the first light deflection region R1 and the second light deflection region R2 may appear in a jagged shape.

[0115] Reference numeral 1804 is an enlarged view of a part of the back surface 11d of the light guide plate 10A in this modified example. Specifically, reference numeral 1804 is an enlarged view of the back surface 11d of the light guide plate 10A in the intermediate region R12. The intermediate region R12 is a region provided between the first light deflection region R1 and the second light deflection region R2 shown by reference numeral 1802. In the intermediate region R12, the first light deflection unit 128 and the second light deflection unit 129 are arranged in a state of being randomly mixed.

[0116] Reference numeral 1805 is an enlarged view of an end portion of the stereoscopic image SI when the intermediate region R12 is provided on the back surface 11d of the light guide plate 10A. When the intermediate region R12 is provided on the back surface 11d of the light guide plate 10A, the boundary between the first light deflection region R1 and the second light deflection region R2 can be blurred. For this reason, a line corresponding to the boundary between the first light deflection region R1 and the second light deflection region R2 becomes difficult to be visually recognized by the observer. For example, at the end portion of the stereoscopic image SI, as shown by reference numeral 1805, it becomes difficult to visually recognize the jagged shape as in the comparative example.

[0117] Note that when the curvature of the light deflection unit 12 is constant, the width of the stereoscopic image SI displayed by the light deflection unit 12 in the direction along the multiple intersection array line 131 becomes wider as the position of the light deflection unit 12 is separated from the incident surface 11a. For this reason, even when displaying a stereoscopic image having a constant width in the direction along the multiple intersection array line 131, it is necessary to switch the curvature of the light deflection unit 12 according to the distance from the incident surface 11a.

[0118] (Modification Example 3) FIG. 19 is a diagram for explaining the light deflection unit 12 according to the third modification of Embodiment 1. In FIG. 19, the three-dimensional image SI displayed by the light deflection unit 12 has a rhombus shape in which the shorter diagonal line is parallel to the array line 13.

[0119] In FIG. 19, it is assumed that the amount of light deflected by each of the light deflection units 12 is constant for each of the complex intersection array lines 131 where the light deflection units 12 are arranged. Under this condition, when displaying such a three-dimensional image SI, if the shape and density of the light deflection unit 12 are constant, the amount of light in a region with a wider width in the direction along the complex intersection array line 131 is smaller than the amount of light in a region with a narrower width. Therefore, in order to reduce the variation in the amount of light, it is necessary to change the shape and density of the light deflection unit 12.

[0120] FIG. 20 is a diagram showing an example of the light deflection unit 12 in a region where the width of the three-dimensional image SI in the direction along the complex intersection array line 131 is wide. In FIG. 20, reference numerals 2001 to 2004 indicate different examples of the light deflection unit 12.

[0121] In a region where the width of the three-dimensional image SI in the direction along the complex intersection array line 131 is wide, for example, as shown by reference numeral 2001, the light deflection unit 12 may simply be enlarged. In this case, the light deflection unit 12 in a region where the width of the three-dimensional image SI in the direction along the complex intersection array line 131 is wide and the light deflection unit 12 in a region where the width of the three-dimensional image SI in the direction along the complex intersection array line 131 is narrow are similar to each other.

[0122] Also, in a region where the width of the three-dimensional image SI in the direction along the complex intersection array line 131 is wide, for example, as shown by reference numeral 2002, the number of the light deflection units 12 may be increased. In this case, the shape of each light deflection unit 12 may be constant regardless of the width of the three-dimensional image SI in the direction along the complex intersection array line 131.

[0123] In addition, in a region where the width of the stereoscopic image SI in the direction along the multiple intersection array line 131 is wide, for example, as shown by reference numerals 2003 and 2004, the width of the light deflection unit 12 in either the direction perpendicular to the multiple intersection array line 131 or the direction along the multiple intersection array line 131 may be increased.

[0124] In a region where the width of the stereoscopic image SI in the direction along the multiple intersection array line 131 is wide, by changing the shape or number of the light deflection units 12 as shown in FIG. 20, fluctuations in the amount of light deflected by the light deflection units 12 can be reduced. For example, when the intermediate value between the maximum value and the minimum value of the amount of light deflected in the reference direction by the light deflection unit 12 is defined as the intermediate value, the minimum value is 0.7 times or more the intermediate value, and the maximum value is 1.3 times or less the intermediate value. Here, the reference direction means the direction intermediate between the first direction and the second direction. Thereby, the fluctuations in the amount of light caused by the width of the stereoscopic image SI in the direction along the multiple intersection array line 131 can be reduced to such an extent that they can be regarded as substantially constant. In particular, the above-described minimum value may be 0.8 times or more the intermediate value, and the maximum value may be 1.2 times or less the intermediate value.

[0125] When the sizes of the light deflection units 12 are the same, for example, the amount of light deflected in the reference direction by the light deflection unit 12 that deflects light in the range of -10° to 10° is approximately twice the amount of light deflected in the reference direction by the light deflection unit 12 that deflects light in the range of -20° to 20°. By setting the size of the light deflection unit 12 that deflects light in the range of -20° to 20° to √2 times the size of the light deflection unit 12 that deflects light in the range of -10° to 10°, the amount of light deflected in the reference direction by these light deflection units 12 can be regarded as substantially constant.

[0126] [Embodiment 2] Other embodiments of the present invention will be described below. For the sake of convenience of explanation, members having the same functions as the members described in the above embodiment are given the same reference numerals, and the description thereof will not be repeated.

[0127] FIG. 21 is a diagram showing an example of the display device 1B according to Embodiment 2. In FIG. 21, reference numeral 2101 is a plan view showing a main part of the display device 1B according to Embodiment 2. Specifically, reference numeral 2101 shows a main part of the light guide plate 10B included in the display device 1B. As shown by reference numeral 2101, the light guide plate 10B is different from the light guide plate 10A in that it includes a plurality of light deflection portions 32 instead of the plurality of light deflection portions 12. Each of the plurality of light deflection portions 32 has an inclined surface 32a (light deflection surface) that deflects light. The directions in which the inclined surfaces 32a of the plurality of light deflection portions 32 arranged on the multiple intersection array line 131 deflect light are dispersed between a first direction toward a first position in the observation space and a second direction toward a second position different from the first position.

[0128] For example, consider a case where the first position exists in a direction of -n° with respect to the direction perpendicular to the back surface 11d, and the second position exists in a direction of +n° with respect to the direction perpendicular to the back surface 11d. In this case, the directions in which the respective inclined surfaces 32a deflect light are dispersed between -n° and +n°. That is, the directions in which the inclined surfaces 32a of the light deflection portions 32 adjacent to each other deflect light change intermittently.

[0129] Reference numerals 2102 to 2104 are graphs showing examples of the display of the stereoscopic image SI by the light guide plate 10B observed from different positions. In reference numerals 2102 to 2104, the horizontal axis represents the angle of the light deflected by the light deflection portion 32, and the vertical axis represents the light quantity.

[0130] In reference numeral 2101, regions R31 to R33 are regions on the back surface 11d. In the light guide plate 10B, the light deflection portions 32 that contribute to the display of the stereoscopic image SI are different depending on the observation position. For example, the light deflection portions 32 arranged in the region R31 contribute to the display of the stereoscopic image SI shown by reference numeral 2102. Also, the light deflection portions 32 arranged in the region R32 contribute to the display of the stereoscopic image SI shown by reference numeral 2103, and the light deflection portions 32 arranged in the region R33 contribute to the display of the stereoscopic image SI shown by reference numeral 2104.

[0131] Therefore, among the stereoscopic images SI, the angles at which light is actually visually recognized vary depending on the observation position between the first direction and the second direction. Accordingly, an effect such that the stereoscopic image SI flickers can be achieved as the observation position varies.

[0132] Specifically, the directions in which the respective inclined surfaces 32a of the light deflection unit 32 deflect light may be randomly distributed between the first direction and the second direction. Thereby, an effect such that the stereoscopic image SI flickers randomly can be achieved as the observation position varies.

[0133] In the example shown by reference numerals 2102 to 2104, the amount of light of the visually recognized light was uniform at the angle at which the light was visually recognized. However, the amount of light at the angle at which the light is visually recognized may vary depending on the angle. For example, as shown in FIG. 21, the amount of light may vary according to the angle at which the light is visually recognized.

[0134] FIG. 22 is a diagram for explaining the direction in which the light deflection unit 32 deflects light in the light guide plate 10B. In FIG. 22, reference numerals 2201 to 2203 indicate different examples of the direction in which the light deflection unit 32 deflects light.

[0135] In the example shown by reference numeral 2201, the direction in which the light deflection unit 32 deflects light is different for each individual light deflection unit 32. In this case, since the stereoscopic image flickers in a granular manner, an impression can be given to the observer that the surface of the stereoscopic image has a texture like that of so-called lame.

[0136] In the example shown by reference numeral 2202, the direction in which the light deflection unit 32 deflects light is different for each group of linearly arranged light deflection units 32. In this case, since the stereoscopic image flickers linearly, an impression like that of a stainless-steel-like depth line can be given to the observer.

[0137] In the example shown by reference numeral 2202, the direction in which the light deflector 32 deflects light is different for each group of light deflectors 32 arranged along the multiple intersection array line 131. However, the direction in which the light deflector 32 deflects light may be different for each group of light deflectors 32 arranged along a line in any direction different from the multiple intersection array line 131. Also, in the example shown by reference numeral 2202, the direction in which the light deflector 32 deflects light is different for each single line. However, the direction in which the light deflector 32 deflects light may be different for each multiple lines. Furthermore, the lengths of the lines on which the light deflectors 32 are arranged may be different from each other.

[0138] In the example shown by reference numeral 2203, the direction in which the light deflector 32 deflects light is different for each group of light deflectors 32 arranged in a certain area. In this case, since the stereoscopic image flickers for each area, an observer can be given an impression as if so-called spangles are arranged on the surface of the stereoscopic image.

[0139] In the example shown by reference numeral 2203, the direction in which the light deflector 32 deflects light is different for each group of 2 to 4 light deflectors 32 arranged in a rectangular area. However, the shape and size of the area for grouping the light deflectors 32 are not limited to the example shown by reference numeral 2203. Also, the shape and size of the area for grouping the light deflectors 32 may be different for each location.

[0140] (Modification Example 1) FIG. 23 is a diagram for explaining a display device 1BA according to a first modification example of Embodiment 2. In FIG. 23, reference numeral 2301 is a plan view showing a main part of the display device 1BA according to this modification example. In the display device 1BA according to this modification example, the light deflector 32 includes a first light deflector group 32A, a second light deflector group 32B, and a third light deflector group 32C.

[0141] The inclined surface 32a of the optical deflector 32 included in the first optical deflector group 32A is a surface whose light deflecting direction is the first direction. The inclined surface 32a of the optical deflector 32 included in the second optical deflector group 32B is a surface whose light deflecting direction is the second direction. The optical deflector 32 included in the third optical deflector group 32C is a surface whose light deflecting direction intermittently changes between the first direction and the second direction. Also, the light quantity of the light deflected by each of the optical deflectors 32 included in the first optical deflector group 32A and the second optical deflector group 32B is larger than the light quantity of the light deflected by each of the optical deflectors 32 included in the third optical deflector group 32C.

[0142] Reference numerals 2302 to 2304 are graphs showing examples of the display of the stereoscopic image SI by the display device 1BA observed from different positions. In reference numerals 2302 to 2304, the horizontal axis represents the angle of the light deflected by the optical deflector 32, and the vertical axis represents the light quantity.

[0143] In this modification, the optical deflector 32 arranged in the region R41 contributes to the display of the stereoscopic image SI shown by reference numeral 2302. Also, the optical deflector 32 arranged in the region R42 contributes to the display of the stereoscopic image SI shown by reference numeral 2303, and the optical deflector 32 arranged in the region R43 contributes to the display of the stereoscopic image SI shown by reference numeral 2304. Any of the regions R41 to R43 includes the respective optical deflectors 32 of the first optical deflector group 32A, the second optical deflector group 32B, and the third optical deflector group 32C.

[0144] Therefore, as shown by reference numerals 2302 to 2304, the regions at both ends of the stereoscopic image SI corresponding to the first direction and the second direction are displayed so that the light quantity is larger than that of the inner region regardless of the observation position. Since whether the inner region of the stereoscopic image SI is displayed or not varies depending on the observation position, an effect such as flickering according to the change in the observation position can be achieved.

[0145] In FIG. 23, the optical deflecting portions 32 of the first optical deflecting portion group 32A and the optical deflecting portions 32 of the second optical deflecting portion group 32B are positioned apart from each other. However, the optical deflecting portions 32 of the first optical deflecting portion group 32A and the optical deflecting portions 32 of the second optical deflecting portion group 32B may be in contact with each other.

[0146] (Modification Example 2) FIG. 24 is a diagram for explaining a display device 1BB according to a second modification example of Embodiment 2. In FIG. 24, reference numeral 2401 is a diagram showing an outline of display in a display device 1BX according to a comparative example of this modification example. Reference numeral 2402 is a graph showing the relationship between the angle and the amount of light of the display in the display device 1BX. Reference numeral 2403 is an image showing an example of an actual display by the display device 1BX. Reference numeral 2404 is a diagram showing an outline of display in the display device 1BB according to this modification example. Reference numeral 2405 is a graph showing the relationship between the angle and the amount of light of the display in the display device 1BB. Reference numeral 2406 is an image showing an example of an actual display by the display device 1BB.

[0147] In the display device 1BX, as shown by reference numeral 2401, the density of the optical deflecting portions 32 on the complex intersection array line 131 is constant regardless of the width of the stereoscopic image SI corresponding to the complex intersection array line 131. The density of the optical deflecting portion 32 here means the number of optical deflecting portions 32 per unit distance on the complex intersection array line 131. For this reason, as shown by reference numerals 2402 and 2403, in a region where the width of the stereoscopic image SI is narrow, the amount of light is larger than in a region where the width of the stereoscopic image SI is wide. Such variation in the amount of light for each position causes a deterioration in the quality of the stereoscopic image SI.

[0148] In the display device 1BB, as shown by reference numeral 2404, the width of the stereoscopic image SI in the direction corresponding to the direction along the multi-intersection array line 131 and the number of light deflection units 32 arranged along the multi-intersection array line 131 have a positive correlation. Specifically, on the multi-intersection array line 131 where the width of the corresponding stereoscopic image SI is narrow, the light deflection units 32 are thinned out compared to those on the multi-intersection array line 131 where the width of the corresponding stereoscopic image SI is wide. Or, on the multi-intersection array line 131 where the width of the corresponding stereoscopic image SI is wide, more light deflection units 32 are arranged compared to those on the multi-intersection array line 131 where the width of the corresponding stereoscopic image SI is narrow. Thereby, as shown by reference numerals 2405 and 2406, fluctuations in the amount of light caused by the width of the stereoscopic image SI can be reduced.

[0149] 〔Embodiment 3〕 FIG. 25 is a plan view showing an example of the display device 1C according to Embodiment 3. The display device 1C is different from the display device 1A in that it includes a light guide plate 10C instead of the light guide plate 10A. An incident light portion 15 is provided near the light source 20 on the incident surface 11a of the light guide plate 10C. The incident light portion 15 is a portion where the incident surface 11a is formed in a concave shape.

[0150] In the light guide plate 10A that does not have the incident light portion 15, the spread of the light incident from the incident surface 11a is at most about 40° with respect to the optical axis, depending on the material of the light guide plate 10A. For this reason, it is difficult to display a stereoscopic image SI having a large size in the direction perpendicular to the optical axis in the vicinity of the light source 20. For example, when the stereoscopic image SI has a size of 20 mm in the direction perpendicular to the optical axis, it is necessary to separate the position where the light deflection unit 12 is arranged by 10 mm or more from the light source 20 in the direction along the optical axis. However, the actual position where the light deflection unit 12 is arranged is also affected by conditions such as the shape of the stereoscopic image SI.

[0151] In the display device 1C, the light from the light source 20 enters the light guide plate 10B from the light incident portion 15. Therefore, the spread of the light incident from the light incident portion 15 in the display device 1C in a plane parallel to the main surface of the light guide plate 10C is larger than the spread of the light incident on the light guide plate 10A from the flat incident surface 11a in the display device 1A. That is, in the light guide plate 10C, the region where light can reach in the vicinity of the incident surface 11a is wider than the region where light can reach in the vicinity of the incident surface 11a of the light guide plate 10A. Therefore, the degree of freedom in the design of the light guide plate 10C is improved.

[0152] In addition to the concave portion described above, the light incident portion 15 may be a slit, a lens array, a diffusion member, or the like disposed between the light source 20 and the incident surface 11a. Examples of the diffusion member include ground glass.

[0153] Also, as in another embodiment described later, in the display device 1C, light may be incident on the light guide plate 10C from another side surface adjacent to the incident surface 11a. However, in this case, there is a possibility that unintended light emission (crosstalk) may occur because the light from the other side surface enters the light deflection portion 12 having a large inclination with respect to the incident surface 11a, which is located in the vicinity of the light incident portion 15. Therefore, for the light deflection portion 12 located in the vicinity of the light incident portion 15, the shape, size, etc. may be appropriately adjusted so as to reduce crosstalk.

[0154] [Embodiment 4] FIG. 26 is a plan view showing an example of a display device 1D according to Embodiment 4. In FIG. 26, reference numerals 2601, 2602, and 2603 indicate different examples of the display device 1D. In the example shown in FIG. 26, the display device 1D is different from the display device 1A in that it includes a light guide plate 10D instead of the light guide plate 10A. The light guide plate 10D can display a plurality of three-dimensional images SIA and SIB by the light incident from the light source 20. In FIG. 26, the three-dimensional image SIA is an image of a circle, and the three-dimensional image SIB is an image of a rectangular character inclined with respect to the incident surface 11a. In FIG. 26, the display device 1D displays the three-dimensional images SIA and SIB by the light from the same light source 20.

[0155] The three-dimensional images SIA and SIB may be adjacent to each other in a direction along the light incident direction, as shown by reference numeral 2601. Further, the three-dimensional images SIA and SIB may be adjacent to each other in a direction perpendicular to the light incident direction, as shown by reference numeral 2602. Further, the three-dimensional images SIA and SIB may be adjacent to each other in a direction different from both the light incident direction and the direction perpendicular thereto, as shown by reference numeral 2603.

[0156] FIG. 27 is a plan view showing another example of the display device 1D. In FIG. 27, reference numerals 2701 and 2702 indicate different examples of the display device 1D. In the example shown in FIG. 27, the display device 1D includes, as a light source 20, a light source 21 that causes light to enter from the incident surface 11a and a light source 22 that causes light to enter from another side surface 11e adjacent to the incident surface 11a. In the display device 1D, the three-dimensional image SIA is displayed by the light from the light source 21, and the three-dimensional image SIB is displayed by the light from the light source 22.

[0157] The light deflection unit 12 for displaying the three-dimensional image SIA and the light deflection unit 12 for displaying the three-dimensional image SIB may be arranged in regions separated from each other, as shown by reference numeral 2701. Further, the light deflection unit 12 for displaying the three-dimensional image SIA and the light deflection unit 12 for displaying the three-dimensional image SIB may be arranged in the same region as each other, as shown by reference numeral 2702. In particular, in the case of the example shown by reference numeral 2702, by switching which of the light sources 21 and 22 is turned on, it is possible to switch which of the three-dimensional image SIA and the three-dimensional image SIB the display device 1D displays.

[0158] FIG. 28 is a plan view showing still another example of the display device 1D. In the example shown in FIG. 28, the display device 1D displays a plurality of three-dimensional images SIA and SIB by the light incident from the incident surface 11a of the light guide plate 10D. In the example shown in FIG. 28, the light source 20 for displaying the three-dimensional image SIA and the light source 20 for displaying the three-dimensional image SIB are separate from each other.

[0159] In the example shown in FIG. 28, the display device 1D has a structure for narrowing the spread of light incident on the light guide plate 10D. For example, a convex lens (not shown) may be disposed between the light source 20 and the light guide plate 10D. Alternatively, the light source 20 may be a highly directional light source such as a bullet LED. Alternatively, the incident surface 11a may have a shape for narrowing the spread of the incident light. Thereby, when the display device 1D displays only one of the stereoscopic images SIA and SIB, the unintentional display of the other is reduced.

[0160] Further, in the display device 1D, the stereoscopic images SIA and SIB are displayed by the light deflection portions 12 in different partial regions of the light guide plate 10D. In other words, the stereoscopic image displayed by the display device 1D includes a stereoscopic image SIA (first stereoscopic image) displayed by the light deflection portion 12 in a first partial region which is a part of the light guide plate 10D, and a stereoscopic image SIB (second stereoscopic image) displayed by the light deflection portion 12 in a second partial region which is a region different from the first partial region of the light guide plate 10D.

[0161] In such a display device 1D, the light deflection portion 12 may be provided such that the stereoscopic images SIA and SIB can be observed from the same observation space. In this case, the observer can observe the first stereoscopic image SIA and the second stereoscopic image SIB from the same observation space.

[0162] Note that, by setting the observation space in which the first stereoscopic image SIA and the second stereoscopic image SIB can be observed as a relatively narrow limited space, it is possible to provide a display in which the first stereoscopic image SIA and the second stereoscopic image SIB can be observed only from the limited space. On the other hand, by setting the observation space in which the first stereoscopic image SIA and the second stereoscopic image SIB can be observed as a relatively wide wide area space, it is possible to provide a display in which the first stereoscopic image SIA and the second stereoscopic image SIB can be observed from a wide range. This wide area space may include a position where the distance from the light guide plate 10D is infinite.

[0163] In the display device 1D, the light deflection unit 12 may be provided such that the observation space in which the stereoscopic image SIA can be observed and the observation space in which the stereoscopic image SIB can be observed are arranged at different positions from each other. In this case, when the observer observes one of the stereoscopic images SIA and the stereoscopic image SIB, it is possible to reduce the reflection of the other.

[0164] (Modification Example 1) FIG. 29 is a plan view showing a display device 1DA according to a first modification example of Embodiment 4. In the example shown in FIG. 29, the distance between the light sources 20 is close compared to other embodiments. Further, the display device 1DA displays a plurality of stereoscopic images SIA1 and SIA2. The stereoscopic images SIA1 and SIA2 are circular images having shapes that can be regarded as identical to each other.

[0165] In this state, by appropriately adjusting the brightness of each of the light sources 20, an effect such that one of the plurality of stereoscopic images SIA1 and SIA2 is a shadow of the other becomes possible. Thereby, it is possible to make the observer feel a sense of depth.

[0166] (Modification Example 2) FIG. 30 is a plan view showing a display device 1DB according to a second modification example of Embodiment 4. The reference numerals 3001 and 3002 in FIG. 30 indicate different examples of the display device 1DB.

[0167] In the example shown by the reference numeral 3001, for simplicity, a state in which all the light sources 20 are lit simultaneously is shown. The display device 1DB performs an effect called a so-called dissolve in which the stereoscopic image SIA switches to the stereoscopic image SIB while moving. Specifically, the light sources 20 that display the stereoscopic images SIA and SIB are controlled so as to switch from a state in which the display of the stereoscopic image SIA is dominant to a state in which the display of the stereoscopic image SIB is dominant. Thereby, an impactful effect in which the stereoscopic image SIA changes to the stereoscopic image SIB as it moves becomes possible.

[0168] Also, in the example shown by reference numeral 3002, the display device 1DB sequentially displays three types of stereoscopic images SIA, SIB, and SIC at different positions. Here, the stereoscopic image SIC is an image of a shape in the middle of deforming the stereoscopic image SIA into the stereoscopic image SIB, and is displayed at a position intermediate between the stereoscopic images SIA and SIB. For simplicity, in reference numeral 3002, the stereoscopic images SIA, SIB, and SIC are shown in a single drawing.

[0169] In the example shown by reference numeral 3002, the light source 20 is controlled so that the stereoscopic images SIA, SIC, and SIB are displayed in this order. Thereby, the display device 1DB performs an effect called so-called morphing in which the stereoscopic image SIA deforms into the stereoscopic images SIC and SIB in order while moving.

[0170] (Modification Example 3) FIG. 31 is a plan view showing a display device 1DC according to a third modification example of Embodiment 4. In the example shown in FIG. 31, the display device 1DC displays a stereoscopic image SIA and planar images PIA and PIB. In FIG. 31, reference numerals 3101 and 3102 indicate the display device 1DC in which the lit light sources 20 are in different states. For simplicity, in FIG. 31, the light sources 20 in the unlit state are omitted.

[0171] As shown by reference numerals 3101 and 3102 in FIG. 31, the display position of the stereoscopic image SIA moves by switching the position of the lit light source 20. Also, when the stereoscopic image SIA is displayed at the position shown by reference numeral 3101, the planar image PIA is displayed together, and when the stereoscopic image SIA is displayed at the position shown by reference numeral 3102, the planar image PIB is displayed together. The planar images PIA and PIB are displayed at fixed positions on the light emitting surface 11c or the back surface 11d of the light guide plate 10D. In the example of FIG. 31, the planar images PIA and PIB are switched according to the position of the lit light source 20. However, the same planar image may be displayed regardless of the position of the lit light source 20.

[0172] In this way, in the display device 1DC, by combining the stereoscopic image SIA and the planar images PIA and PIB, a more impactful presentation can be achieved. Further, by the observer referring to the planar images PIA and PIB displayed on the emission surface 11c or the back surface 11d, the depth perception of the stereoscopic image SIA displayed deeper than the light guide plate 10D is further emphasized.

[0173] 〔Embodiment 5〕 FIG. 32 is a diagram showing the display devices 1EA, 1EB, and 1EC according to Embodiment 5. In FIG. 32, reference numeral 3201 is a perspective view showing an outline of the display device 1EA, reference numeral 3202 is a perspective view showing an outline of the display device 1EB, and reference numeral 3203 is a perspective view and a plan view showing an outline of the display device 1EC.

[0174] As shown by reference numeral 3201, the display device 1EA includes a light guide plate 10EA and an auxiliary light guide 16A instead of the light guide plate 10A. The light guide plate 10EA may have the same configuration as the light guide plate 10A. The auxiliary light guide 16A may have the same configuration as the light guide plate 10A, except that it does not have the light deflection portion 12.

[0175] Further, the display device 1EA further includes a light source 41 which is a light source different from the light source 20. The light emitted from the light source 41 is incident on the light guide plate 10EA via the auxiliary light guide 16A and is emitted from the emission surface 11c. The distance until the light from the light source 41 is emitted from the emission surface 11c is longer by the amount of the auxiliary light guide 16A compared to the distance until the light from the light source 20 is emitted from the emission surface 11c. For this reason, in the display device 1EA, a region CS1 which is a set of intersections for the light from the light source 20 and a region CS2 which is a set of intersections for the light from the light source 41 are generated. In the region CS1 and the region CS2, the amount of depth with respect to the light guide plate 10EA, that is, the distance seen from the light guide plate 10EA, is different from each other.

[0176] As shown by reference numeral 3202, the display device 1EB is different from the display device 1A in that it includes a light guide plate 10EB instead of the light guide plate 10A. The light guide plate 10EB is different from the light guide plate 10A in that it has a recess 16B. The recess 16B is a recess formed in the back surface 11d of the light guide plate 10EB.

[0177] Further, the display device 1EB further includes a light source 42 that is a light source different from the light source 20. The light source 20 is omitted in reference numeral 3202. The light source 42 is housed in the recess 16B. The distance until the light from the light source 42 is emitted from the emission surface 11c is shorter by the distance between the incident surface 11a and the recess 16B compared to the distance until the light from the light source 20 is emitted from the emission surface 11c. For this reason, in the display device 1EB, a region CS1 (see reference numeral 3201) of the set of intersections for the light from the light source 20 and a region CS3 of the set of intersections for the light from the light source 42 are generated. In the region CS1 and the region CS3, the amount of depth with respect to the light guide plate 10EB is different from each other.

[0178] As shown by reference numeral 3203, the display device 1EC is different from the display device 1A in that it includes a light guide plate 10EC instead of the light guide plate 10A. The light guide plate 10EC is different from the light guide plate 10A in that an intermediate light incident portion 16C is formed. The intermediate light incident portion 16C is a portion provided on the side surface 11e of the light guide plate 10EC adjacent to the incident surface 11a for making light incident on the light guide plate 10EC.

[0179] In addition, the display device 1EC further includes a light source 43 that is a light source different from the light source 20. The light source 43 makes light enter the light guide plate 10EC from the intermediate light incident portion 16C. Further, the light source 20 in the display device 1EC is disposed near the side surface 11e such that the optical axis of the light from the light source 20 passes through the light source 43. The distance until the light from the light source 43 is emitted from the emission surface 11c is shorter by the distance between the incident surface 11a and the intermediate light incident portion 16C as compared with the distance until the light from the light source 20 is emitted from the emission surface 11c. For this reason, in the display device 1EC, a region CS1 (see reference numeral 3201) of a set of intersections for the light from the light source 20 and a region CS4 of a set of intersections for the light from the light source 43 are generated. The amounts of depth with respect to the light guide plate 10EC are different between the region CS1 and the region CS4.

[0180] As described above, in each of the display devices 1EA, 1EB, and 1EC, a plurality of intersections having different amounts of depth are generated for each array line 13. Therefore, each of the display devices 1EA, 1EB, and 1EC can display a plurality of stereoscopic images having different amounts of depth as a whole.

[0181] (Modification example) FIG. 33 is a diagram showing display devices 1ED, 1EE, and 1EF according to a modification example of Embodiment 5. In FIG. 33, reference numeral 3301 is a perspective view showing an outline of the display device 1ED, reference numeral 3302 is a perspective view showing an outline of the display device 1EE, and reference numeral 3303 is a perspective view showing an outline of the display device 1EF.

[0182] As shown by reference numeral 3301, the display device 1ED includes a light guide plate 10ED, a lens 16D, and a light source 44. The light guide plate 10ED may have the same configuration as the light guide plate 10A. The light source 44 makes light enter the light guide plate 10ED through the lens 16D. Further, although not shown in reference numeral 3301, the display device 1ED also includes the light source 20. In such a display device 1ED, a region CS1 (see reference numeral 3201) of a set of intersections for the light from the light source 20 and a region CS5 of a set of intersections for the light from the light source 44 are generated.

[0183] In the regions CS1 and CS5, the depth amounts with respect to the light guide plate 10EC are different from each other. Depending on the characteristics of the lens 16D, the region CS5 may occur closer to the observer side than the light guide plate 10ED as shown by reference numeral 3301. Even with such a display device 1ED, a plurality of three-dimensional images with different depth amounts can be displayed.

[0184] As shown by reference numeral 3302, the display device 1EE is different from the display device 1A in that it includes a light guide plate 10EE instead of the light guide plate 10A. The light guide plate 10EE is different from the light guide plate 10A in that a retroreflective structure 16E is formed on a side surface 11b which is a side surface facing the incident surface 11a.

[0185] The retroreflective structure 16E reflects the light incident on the side surface 11b in a direction that can be regarded as substantially the same as the incident direction. However, the display device 1EE may have a structure in which a separate retroreflective member having the same function as the retroreflective structure 16E is attached to the side surface 11b of the light guide plate 10A instead of having the light guide plate 10EE.

[0186] In the display device 1EE, a region CS6 of a set of intersections is formed by the light reflected by the side surface 11b, which is different from the region CS1 of the set of intersections. Depending on the shape of the light deflection unit 12, the region CS6 is located closer to the observer side than the light guide plate 10EE as shown by reference numeral 3302. Even with such a display device 1EE, a plurality of three-dimensional images with different depth amounts can be displayed.

[0187] As shown by reference numeral 3303, the display device 1EF includes a retroreflective plate 16F in addition to the configuration of the display device 1A. The retroreflective plate 16F reflects the incident light in a direction that can be regarded as substantially the same as the incident direction. The retroreflective plate 16F is disposed on the emission surface 11c side of the light guide plate 10A. Considering visibility, in reference numeral 3303, the positional relationship between the emission surface 11c and the back surface 11d is reversed from other figures.

[0188] In this modification, the observer observes the display device 1EF from the side of the back surface 11d. The light reflected by the retroreflective plate 16F forms a region CS7 of the set of intersections on the side of the observer with respect to the light guide plate 10A. Therefore, according to the display device 1EF, a stereoscopic image can be displayed at a position closer to the observer than the light guide plate 10A by using the light guide plate 10A. That is, the observer can observe a stereoscopic image protruding forward from the light guide plate 10A.

[0189] FIG. 34 is a diagram showing display devices 1EG and 1EH according to another modification different from that shown in FIG. 33 of Embodiment 4. In FIG. 34, reference numeral 3401 is a perspective view showing an outline of the display device 1EG, and reference numeral 3402 is a perspective view showing an outline of the display device 1EH.

[0190] As shown by reference numeral 3401, the display device 1EG includes a light source 45 different from the light source 20 in addition to the configuration of the display device 1A. The light source 45 makes light enter the light guide plate 10A from the side surface 11b facing the incident surface 11a. Such a display device 1EG also has the same effects as the display device 1A and the like.

[0191] As shown by reference numeral 3402, the display device 1EH is different from the display device 1A in that it includes a light guide plate 10EH instead of the light guide plate 10A. The light guide plate 10EH is different from the light guide plate 10A in that the position of the incident surface 11a other than the position where the light from the light source 20 enters and the side surface 11b serve as a reflecting surface for reflecting light.

[0192] In the display device 1EH, among the light incident from the light source 20 to the light guide plate 10EH, the light incident on the side surface 11b is reflected and further guided inside the light guide plate 10EH. The light reflected by the side surface 11b behaves as light from a virtual light source 46 located on the side opposite to the light source 20 with respect to the side surface 11b, and forms a region CS8 of a set of intersections different from the region CS1 of the set of intersections. Such a display device 1EH also has the same effects as the display device 1A and the like.

[0193] 〔Embodiment 6〕 FIG. 35 is a plan view showing an example of the array line 13 according to Embodiment 6. In the above-described embodiments, the array lines 13 are all a plurality of straight lines parallel to each other, but the array lines 13 are not limited to this. The array lines 13 may be straight lines, curves, combinations of two or more straight lines, combinations of two or more curves, or combinations of one or more straight lines and one or more curves. Specific examples of such array lines 13 are shown by reference numerals 3501, 3501, and 3503 in FIG. 35.

[0194] In a display device 1A or the like, when the array line 13 has such a shape, by switching the position of the light source 20 to be lit or moving the position where the observer observes the stereoscopic image SI, an expression can be achieved in which the stereoscopic image SI moves along the array line 13. Therefore, the degree of freedom in expressing the stereoscopic image SI is improved.

[0195] FIG. 36 is a plan view showing an example of the light guide plate 10F according to Embodiment 6. The light guide plate 10F is different from the light guide plate 10A in that it has an array line 13 that is not linear. In FIG. 36, reference numerals 3601 and 3602 indicate different examples of the light guide plate 10F. In FIG. 36, the array line 13 is illustrated as an arrow indicating the moving direction of the stereoscopic image. Also, in reference numeral 3602, the stereoscopic images SIA and SIB that appear at a plurality of positions during the movement are shown in a single drawing.

[0196] In the light guide plate 10F shown by reference numeral 3601, the array line 13 (see FIG. 35) is bent along the arrow in the figure. For this reason, the stereoscopic image displayed by the light guide plate 10F also moves along the arrow in the figure. By reducing the width and period of the bending of the array line 13, an effect can be achieved such that the stereoscopic image appears to move linearly along the incident surface 11a.

[0197] In the light guide plate 10F shown by reference sign 3602, the array line 13 on which the light deflection part 12 for displaying the stereoscopic image SIA is arranged has a curved shape convex in the direction approaching the incident surface 11a. On the other hand, the array line 13 on which the light deflection part 12 for displaying the stereoscopic image SIB is arranged has a curved shape convex in the direction away from the incident surface 11a. The array line 13 on which the light deflection part 12 for displaying the stereoscopic image SIA is arranged and the array line 13 on which the light deflection part 12 for displaying the stereoscopic image SIB is arranged intersect with each other. In this light guide plate 10F, as shown by reference sign 3602, the stereoscopic images SIA and SIB temporarily exchange their positions in the direction perpendicular to the incident surface 11a during the process of moving along the incident surface 11a.

[0198] 〔Embodiment 7〕 FIG. 37 is a plan view showing an example of the array line 13 according to Embodiment 7. In the above-described embodiments, the start point and the end point of each of the array lines 13 are single lines, but the array line 13 is not limited to this. The array line 13 may include branch points or merging points of a plurality of lines. Specific examples of such an array line 13 are shown by reference signs 3701, 3702, and 3703 in FIG. 37.

[0199] In a display device 1A or the like, when the array line 13 has such a shape, by switching the position of the light source 20 that is lit or moving the position where the observer observes the stereoscopic image, an expression can be achieved in which the stereoscopic image splits or merges along the array line 13. Therefore, the degree of freedom in expressing the stereoscopic image is improved.

[0200] FIG. 38 is a plan view showing an example of the light guide plate 10G according to Embodiment 7. The light guide plate 10G is different from the light guide plate 10A in that the array line 13 includes branch points or merging points of a plurality of lines. In FIG. 38, reference signs 3801 and 3802 show different examples of the light guide plate 10G. In FIG. 38, the stereoscopic image SIA that appears at a plurality of positions during the movement is shown in a single drawing. Also, in FIG. 38, the array line 13 is illustrated as an arrow indicating the moving direction of the stereoscopic image SIA.

[0201] In the light guide plate 10G shown by reference numeral 3801 in FIG. 38, the array lines 13 have a shape that branches in two directions from one end. In this case, the stereoscopic image SIA is a single image at the start point of movement, but splits into two and moves.

[0202] Also, in the light guide plate 10G shown by reference numeral 3802 in FIG. 38, the array lines 13 have a shape that branches in four directions from one point. In this case, the stereoscopic image SIA is a single image at the start point of movement, but splits into four and moves.

[0203] In all the examples shown in FIG. 38, the stereoscopic image SIA split into a plurality of images. However, as described above, according to the array lines 13 of Embodiment 7, a plurality of stereoscopic images can also be merged. For example, in the example shown in FIG. 38, by reversing the start position and the end position of the movement, two or four stereoscopic images SIA can be merged.

[0204] [Embodiment 8] FIG. 39 is a plan view showing an example of the array lines 13 according to Embodiment 8. In FIG. 39, reference numerals 3901 and 3902 indicate different examples of the array lines 13 according to Embodiment 8.

[0205] For example, as shown by reference numeral 3901 in FIG. 39, the array lines 13 may include linear regions that are not parallel to each other. In a display device 1A or the like, when the array lines 13 have such a shape, by switching the position of the light source 20 that lights up or moving the position where the observer observes the stereoscopic image, an expression can be achieved in which the stereoscopic image expands or contracts along the array lines 13. Therefore, the degree of freedom in the expression of the stereoscopic image SI is improved.

[0206] Also, when the array lines 13 are not parallel to each other and there is a region where the interval between the array lines 13 becomes excessively wide, for example, as shown by reference numeral 3901 in FIG. 39, auxiliary array lines 17 may be added to the region. In this case, it is possible to suppress a decrease in the image quality of the stereoscopic image while maintaining the degree of freedom in the expression of the stereoscopic image.

[0207] FIG. 40 is a plan view showing an example of the light guide plate 10H according to Embodiment 8. The light guide plate 10H is different from the light guide plate 10A in that the array lines 13 are not parallel to each other. In FIG. 40, a stereoscopic image SIA that appears at a plurality of positions during movement is shown in a single drawing. Also, in FIG. 40, the array lines 13 are illustrated as arrows indicating the moving direction of the stereoscopic image SIA.

[0208] In the light guide plate 10H shown in FIG. 40, the interval between the plurality of array lines 13 widens as it goes from the start point to the end point of the movement of the stereoscopic image SIA. In this case, the stereoscopic image SIA expands as it moves along the array lines 13. Also, in the light guide plate 10H, contrary to the example of FIG. 40, the interval between the plurality of array lines 13 may narrow as it goes from the start point to the end point of the movement of the stereoscopic image SIA. In this case, the stereoscopic image SIA shrinks as it moves along the array lines 13.

[0209] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0210] 〔Summary〕 The present disclosure can also be expressed as follows.

[0211] The light guide plate according to Embodiment 1 of the present disclosure is a light guide plate for displaying a stereoscopic image due to parallax, and includes an incident surface on which light from a light source is incident, an exit surface from which the light is emitted, and a plurality of light deflection portions that deflect the light incident from the incident surface and guided and cause the light to be emitted from the exit surface. The plurality of light deflection portions are arranged on an arrangement line that is a linear arrangement region, and a point on the exit surface that emits first emitted light deflected by the light deflection portion to an angular range irradiated to one eye of an observer observing the exit surface from within a predetermined range of an observation space and its vicinity is defined as a first emission point, and a point on the exit surface that emits second emitted light deflected by the light deflection portion to an angular range irradiated to the other eye of the observer and its vicinity is defined as a second emission point. A plurality of the light deflection portions arranged on the arrangement line are provided so that a straight line passing through the first emission point and the center of the one eye and a straight line passing through the second emission point and the center of the other eye intersect with each other to form an intersection point. A plurality of the arrangement lines are provided, and at least one of the arrangement lines is a multi-intersection arrangement line on which a plurality of the light deflection portions are provided so as to form the intersection point at a plurality of positions for each position of the one eye and the other eye.

[0212] The light guide plate according to Embodiment 2 of the present disclosure is, in Embodiment 1, each of the plurality of light deflection portions has a light deflection surface for deflecting the light, and the light deflection surface of the light deflection portion arranged on the multi-intersection arrangement line is a curved surface in which the direction of deflecting the light emitted from one of the light sources continuously changes from a first direction toward a first position in the observation space to a second direction toward a second position different from the first position.

[0213] The light guide plate according to Embodiment 3 of the present disclosure is, in Embodiment 2, the minimum value of the amount of light corresponding to the direction of deflecting the light deflected by the light deflection portion arranged on the multi-intersection arrangement line is 0.7 times or more of the maximum value of the amount of light.

[0214] The light guide plate according to aspect 4 of the present disclosure, in aspect 2, the average of the amount of light of the light deflected by the light deflection portion disposed on the complex intersection array line in the region of the outer peripheral portion of the stereoscopic image is the average of the amount of light of the light deflected by the light deflection portion disposed on the complex intersection array line in the region inside the region of the outer peripheral portion of the stereoscopic image. The light guide plate according to claim 2, which is at least twice as large.

[0215] The light guide plate according to aspect 5 of the present disclosure, in any one of aspects 2 to 4, the light deflection portion includes a first light deflection portion having a first curvature of the curved surface and a second curvature different from the first curvature. A second light deflection portion, and an intermediate region in which the first light deflection portion and the second light deflection portion are arranged in a randomly mixed state is provided between a first light deflection region in which the first light deflection portion is arranged and a second light deflection region in which the second light deflection portion is arranged.

[0216] The light guide plate according to aspect 6 of the present disclosure, in any one of aspects 2 to 5, the amount of light deflected by each of the plurality of light deflection portions is constant for each complex intersection array line on which the light deflection portion is arranged. When the intermediate value between the maximum value and the minimum value of the amount of light deflected in the reference direction, which is the intermediate direction between the first direction and the second direction, by the light deflection portion is defined as the intermediate value, the minimum value is 0.7 times or more of the intermediate value, and the maximum value is 1.3 times or less of the intermediate value.

[0217] The light guide plate according to aspect 7 of the present disclosure, in aspect 1, each of the light deflection portions has a light deflection surface for deflecting the light, and the directions in which the light deflection surfaces of the plurality of light deflection portions arranged on the complex intersection array line deflect the light are different from the first position in the first direction in the observation space. It is dispersed between the first direction toward the first position and the second direction toward the second position.

[0218] The light guide plate according to aspect 8 of the present disclosure, in aspect 7, the directions in which the respective light deflection surfaces of the plurality of light deflection portions deflect the light are randomly dispersed between the first direction and the second direction.

[0219] In the light guide plate according to Embodiment 9 of the present disclosure, in Embodiment 7 or 8, the plurality of light deflection parts include a first light deflection part group that is a set of the light deflection parts that deflect the light in the first direction with respect to one eye and the other eye at any position, a second light deflection part group that is a set of the light deflection parts that deflect the light in the second direction with respect to one eye and the other eye at any position, and a third light deflection part group that is a set of the light deflection parts that deflect the light in a random direction from the first direction to the second direction.

[0220] In the light guide plate according to Embodiment 10 of the present disclosure, in any one of Embodiments 7 to 9, the width of the stereoscopic image in the direction corresponding to the direction along the complex intersection array line and the number of the light deflection parts arranged along the complex intersection array line have a positive correlation.

[0221] The display device according to Embodiment 11 of the present disclosure includes the light guide plate of Embodiment 1, a plurality of light sources that make light incident on the light guide plate from the incident surface, and a control unit that controls the plurality of light sources.

[0222] In the display device according to Embodiment 12 of the present disclosure, in Embodiment 11, the plurality of light sources are linearly arranged, and the control unit controls the plurality of light sources to be sequentially turned on and off from one end to the other end of the line.

[0223] In the display device according to Embodiment 13 of the present disclosure, in Embodiment 11, the plurality of light sources are linearly arranged, and the control unit controls the plurality of light sources to be sequentially turned on and off from an arbitrary point other than one end and the other end of the line to both one end and the other end.

[0224] The gaming machine according to Embodiment 14 of the present disclosure includes the display device according to any one of Embodiments 11 to 13.

[0225] The in-vehicle display according to Embodiment 15 of the present disclosure includes the display device according to any one of Embodiments 11 to 13.

Explanation of Signs

[0226] 1A, 1B, 1BA, 1BB, 1C, 1D, 1DA, 1DB, 1DC, 1EA, 1EB, 1EC, 1ED, 1EE, 1EF, 1EG, 1EH represent devices 10A, 10B, 10C, 10D, 10EA, 10EB, 10EC, 10ED, 10EE, 10EH, 10F, 10G, 10H light guide plates 11a incident surface 11c exit surface 12, 32, 121, 122, 123, 124, 125 light deflection parts 128 first light deflection part 129 second light deflection part 12a, 32a inclined surfaces (light deflection surfaces) 13, 17 array lines 131 complex intersection array line 20, 21, 22, 41, 42, 43, 44, 45, 46 light sources 30 control unit 32A first light deflection part group 32B second light deflection part group 32C third light deflection part group 100 gaming machine

Claims

1. A light guide plate for displaying a stereoscopic image by parallax, comprising: an incident surface on which light from a light source is incident; an exit surface from which the light exits; a plurality of light deflection portions that deflect the light incident from the incident surface and guided, and cause the light to exit from the exit surface; the plurality of light deflection portions are arranged on an arrangement line which is a linear arrangement region; a point on the exit surface that emits first exit light deflected by the light deflection portion to an angular range irradiated to one eye of an observer observing the exit surface from within a predetermined range of an observation space and its vicinity is defined as a first exit point, and a point on the exit surface that emits second exit light deflected by the light deflection portion to an angular range irradiated to the other eye of the observer and its vicinity is defined as a second exit point. A plurality of the light deflection portions are arranged on the arrangement line such that a straight line passing through the first exit point and the center of the one eye and a straight line passing through the second exit point and the center of the other eye intersect with each other to form an intersection point; a plurality of the arrangement lines are provided, and at least one of the arrangement lines is a multi-intersection arrangement line in which a plurality of the light deflection portions are provided so as to form the intersection points at a plurality of positions for each position of the one eye and the other eye.

2. Each of the plurality of light deflection portions has a light deflection surface for deflecting the light; the light deflection surface of the light deflection portion arranged on the multi-intersection arrangement line is a curved surface in which the direction of deflecting the light emitted from one of the light sources continuously changes from a first direction toward a first position in the observation space to a second direction toward a second position different from the first position.

3. The minimum value of the amount of light corresponding to the direction of deflecting the light deflected by the light deflection portion arranged on the multi-intersection arrangement line is 0.7 times or more of the maximum value of the amount of light.

4. The average amount of light in the region of the outer periphery of the stereoscopic image of the light deflected by the light deflection portion arranged on the multi-intersection arrangement line is 2 times or more of the average amount of light in the region inside the region of the outer periphery of the stereoscopic image of the light deflected by the light deflection portion arranged on the multi-intersection arrangement line.

5. the light deflection portion includes a first light deflection portion having a first curvature which is the curvature of the curved surface, and a second light deflection portion having a second curvature different from the first curvature. Between the first light deflection region where the first light deflection unit is disposed and the second light deflection region where the second light deflection unit is disposed, there is provided an intermediate region where the first light deflection unit and the second light deflection unit are arranged in a randomly mixed state. The light guide plate according to claim 2.

6. The amount of light deflected by each of the plurality of light deflection units is constant for each of the plurality of intersection array lines where the light deflection units are disposed. When the intermediate value is the intermediate value between the maximum value and the minimum value of the amount of light deflected in a reference direction which is an intermediate direction between the first direction and the second direction by the light deflection unit. The minimum value is 0.7 times or more of the intermediate value, and the maximum value is 1.3 times or less of the intermediate value. The light guide plate according to claim 2.

7. Each of the light deflection units has a light deflection surface for deflecting the light. The directions in which the light deflection surfaces of the plurality of light deflection units disposed on the plurality of intersection array lines deflect the light are dispersed between a first direction toward a first position in the observation space and a second direction toward a second position different from the first position. The light guide plate according to claim 1.

8. The directions in which the respective light deflection surfaces of the plurality of light deflection units deflect the light are randomly dispersed between the first direction and the second direction. The light guide plate according to claim 7.

9. The plurality of light deflection units For one eye and the other eye at an arbitrary position, a first light deflection unit group which is a set of light deflection units that deflect the light in the first direction, For one eye and the other eye at an arbitrary position, a second light deflection unit group which is a set of light deflection units that deflect the light in the second direction, And a third light deflection unit group which is a set of light deflection units that deflect the light in a random direction between the first direction and the second direction. The light guide plate according to claim 7.

10. The width of the stereoscopic image in a direction corresponding to the direction along the plurality of intersection array lines and the number of the light deflection units arranged along the plurality of intersection array lines have a positive correlation. The light guide plate according to claim 7.

11. A display device comprising the light guide plate according to claim 1, A plurality of light sources for irradiating the light guide plate with light from the incident surface, And a control unit for controlling the plurality of light sources.

12. The plurality of light sources are arranged linearly. The display device according to claim 11, wherein the control unit controls the plurality of light sources to be sequentially turned on and off from one end to the other end of the linear shape.

13. The plurality of light sources are arranged linearly, The display device according to claim 11, wherein the control unit controls the plurality of light sources to be sequentially turned on and off from an arbitrary point other than one end and the other end of the linear shape to both one end and the other end.

14. A gaming machine including the display device according to any one of claims 11 to 13.

15. An in-vehicle display including the display device according to any one of claims 11 to 13.

Images