Light guide plate, display device, input device, and equipment having display device

Abstract

The present invention provides a light guide plate, a display device, an input device, and a device having the display device, wherein the light guide plate displays a stereoscopic image with improved grayscale expression in space. The light guide plate (10) includes a plurality of light path deflection parts (21) arranged in a matrix, each light path deflection part (21) includes a plurality of light path deflection part groups, and a first unit including a first deflection part that deflects light into a first angle range and does not include a second deflection part that deflects light into a second angle range adjacent to the first angle range and a second unit including the second deflection part and not including the first deflection part are periodically arranged.

Description

Technical Field

[0001] The present invention relates to a light guide plate and the like for displaying a three-dimensional image. Background Art

[0002] Conventionally, as a light guide plate and an optical device for displaying a three-dimensional image, for example, Patent Document 1 is known.

[0003] The optical device 1A of Patent Document 1 comprises: a light guide plate 10 for guiding light incident from a light source 2 and emitting it from an emission surface 12; a plurality of light path deflecting units 20 disposed on the light guide plate 10 for deflecting the light path of the guided light and emitting it, thereby forming an image in space ( Figure 1 ). The optical path deflection unit 20 comprises: an optical path deflection unit group 21 for surface image, which deflects the light to be guided and emits it, so as to image the surface image FI in space; and an optical path deflection unit group 24 for contour image, which deflects the light to be guided and emits it, so as to image the contour image BI in space.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: (Japanese) Patent Publication No. 2018-010223 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] However, the existing optical device 1A has room for improvement in the following aspects.

[0009] Patent Document 1 Figure 1 The figure shows the situation where a stereoscopic image I is formed in space. In the figure, the stereoscopic image I describes three surface images FI. In the case where the three surface images FI produce grayscale differences, a method can be considered to not use (eliminate) a part of the surface image optical path deflection unit group 21 on the light guide plate corresponding to a part of the surface image FI. Fig.16 and Fig.17 This structure will be described.

[0010] Fig.16 This is a diagram showing the state of light being emitted from all the light path deflection unit groups 200 in the conventional light guide plate 100. As shown in the figure, light is emitted from all the light path deflection unit groups 200 to form an image in the air. The grayscale at this time is 100 grayscale.

[0011] Fig.17 1 is a diagram showing a state in which, in a conventional light guide plate 100 , optical path deflection unit groups 200 that emit light and optical path deflection unit groups 200 that do not emit light are alternately arranged. Fig.17The structure shown is based on the production of Fig.16 The structure shown in the figure is 50% of the structure (100 grayscale) with 50 grayscale as the research object. The dotted line in the figure schematically represents the situation where the light path deflection unit group 200 is eliminated and no light is emitted. Fig.17 In the case of the structure shown, the light emitted from a part of the optical path deflection unit group 200 does not form an image in the air, and the light emitting point is fixed from any position of the observer. In this way, the image that should be seen in space is located at the position where the ejection amount is 0, that is, on the light guide plate 100.

[0012] In addition, as in Patent Document 1 Figure 1 The method of generating grayscale difference between the three surface images FI shown in the patent document 1 may also be considered to adjust Fig.13 The length (or height) of the prism is shown in the method. Fig.18 , to explain this.

[0013] Fig.18 This is a top view of a triangular prism with different lengths constituting an optical path deflection unit group. As shown in the figure, the lengths of prisms 1000, 1001, and 1002 are 4L, 2L, and L, respectively, and the widths are all W. The grayscale produced by prism 1000 is 100 grayscales. At this time, because the length of prism 1001 is 2L, the brightness is reduced by 50% compared to prism 1000, which is 50 grayscales. Because the length of prism 1002 is L, the brightness is reduced by 25% compared to prism 1000, which is 25 grayscales.

[0014] However, the prism has a processing limit after all, and it is difficult to be less than 50μm. Therefore, in the case of 4L=100μm, it is difficult to make a prism with a length less than 2L (that is, prism 1002). Considering the above-mentioned processing limit, it is also possible to consider designing 4L=200μm, but in this case, the size of the optical path deflection unit group increases, and as a result, the resolution of the optical device decreases. Therefore, simply changing the shape of the prism will face problems such as processing limitations or reduced resolution.

[0015] The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a light guide plate and the like for displaying a three-dimensional image with improved grayscale expression in space.

[0016] Technical solutions for solving technical problems

[0017] In order to solve the above-mentioned problem, a light guide plate in one embodiment of the present invention is a light guide plate that displays a specified image as a real image or a virtual image in space, and its structure is as follows, that is, it includes a plurality of units arranged in a matrix, each unit includes a plurality of deflection units that deflect and emit light incident on the light guide plate in a plurality of directions, and in order to display a plurality of points of an intermediate grayscale line or surface constituting the image, a first unit and a second unit are periodically arranged, the first unit includes a first deflection unit that deflects light into a first angle range but does not include a second deflection unit that deflects light into a second angle range adjacent to the first angle range, and the second unit does not include the first deflection unit but includes the second deflection unit.

[0018] By having such a structure, the light guide plate of one embodiment of the present invention can reduce the number of image points in the air. Therefore, the light guide plate of one embodiment of the present invention can display a three-dimensional image with improved grayscale expression in the air while maintaining the three-dimensional effect.

[0019] In the light guide plate of one embodiment of the present invention, the first unit may include a third deflection unit that deflects light into a third angle range adjacent to the second angle range, and the second unit may not include the third deflection unit.

[0020] In addition, the light guide plate according to one embodiment of the present invention may have a structure in which the first units and the second units are alternately arranged.

[0021] By having the above-described structures, the light guide plate according to one embodiment of the present invention can display a three-dimensional image with improved grayscale expression in mid-air while maintaining a three-dimensional effect.

[0022] In the light guide plate of one embodiment of the present invention, the structure may be as follows, that is, the first unit and the second unit do not include a third deflection unit for deflecting light toward a third angle range adjacent to the second angle range, and do not include a fourth deflection unit for deflecting light toward a fourth angle range adjacent to the third angle range, and also include: a third unit, which includes the third deflection unit but does not include the first deflection unit, the second deflection unit, and the fourth deflection unit; a fourth unit, which includes the fourth deflection unit but does not include the first deflection unit to the third deflection unit, and the first unit to the fourth unit are periodically arranged.

[0023] By having such a structure, the light guide plate of one embodiment of the present invention can further reduce the grayscale. Therefore, the light guide plate of one embodiment of the present invention can display a three-dimensional image with improved grayscale expression in mid-air while maintaining the three-dimensional effect.

[0024] In the light guide plate according to one aspect of the present invention, the plurality of deflection units may include a deflection unit having at least one of a length and a height different from the others.

[0025] With the above structure, the light guide plate according to one embodiment of the present invention can display a three-dimensional image with richer grayscale expression in mid-air depending on the shape of the polarizing portion.

[0026] A display device according to one aspect of the present invention may include any of the above-mentioned light guide plates and a light source for irradiating incident light onto the light guide plate.

[0027] An input device according to one embodiment of the present invention may include the display device described above and a sensor unit that detects an object.

[0028] A device according to one embodiment of the present invention may have a structure including the above-mentioned display device.

[0029] With the above-described structure, the display device, the input device, and the apparatus according to one embodiment of the present invention can display a stereoscopic image with improved grayscale expression in space.

[0030] Effects of the Invention

[0031] According to one embodiment of the present invention, it is possible to provide a light guide plate that displays a three-dimensional image with improved grayscale expression in space. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a perspective view showing the structure of the optical device according to the present embodiment.

[0033] Figure 2 It is a cross-sectional view showing the structure of the optical device according to the present embodiment.

[0034] Figure 3 It is a plan view showing a structure for forming a stereoscopic image using the optical device according to this embodiment.

[0035] Figure 4 This is a front view showing an example of a stereoscopic image formed by the optical device according to the present embodiment.

[0036] Figure 5 This is a perspective view showing a structure of an example of a prism formed on a light guide plate of the optical device according to the present embodiment.

[0037] Figure 6 The diagram shows usage examples and arrangement examples of the optical path deflection unit group.

[0038] Figure 7 This is a diagram showing how light emitted from a plurality of optical path deflecting units forms an image in the air.

[0039] Figure 8 Yes Description Figure 7 Figure 1 shows the main components of the .

[0040] Fig. 9 The figure shows the light-emitting pattern on the light guide plate.

[0041] Fig.10 An example of a three-dimensional image with improved grayscale expression displayed in space using a light guide plate is shown.

[0042] Fig.11 This is a diagram showing a light emission pattern on the light guide plate when the grayscale is assumed to be 100.

[0043] Fig.12 This is a diagram showing a light emission pattern on the light guide plate assuming 50 grayscales.

[0044] Fig.13 This is a diagram showing a light emission pattern on the light guide plate assuming 50 grayscales.

[0045] Fig.14 This is a diagram showing a light-emitting pattern on a light guide plate assuming 25 gray levels.

[0046] Fig.15 This is a diagram showing a light-emitting pattern on a light guide plate assuming 25 gray levels.

[0047] Fig.16 This is a diagram showing a state in which light is emitted from all the light path deflecting unit groups in a conventional light guide plate.

[0048] Fig.17 This is a diagram showing a state in which, in a conventional light guide plate, a light path deflecting unit group that emits light and a light path deflecting unit group that does not emit light are alternately arranged.

[0049] Fig.18 This is a schematic plan view of prisms having triangular prisms of different lengths that constitute an optical path deflecting unit group. DETAILED DESCRIPTION

[0050] Hereinafter, an embodiment of one aspect of the present invention (hereinafter also referred to as “this embodiment”) will be described based on the drawings.

[0051] [First embodiment]

[0052] based on Figure 1 etc., an embodiment of the present invention is described below.

[0053] (Structure of optical device)

[0054] Figure 1 It is a perspective view showing the structure of the optical device 1A. Figure 2 1A is a cross-sectional view showing the structure of the optical device 1A. Figure 1 and Figure 2, the structure of the optical device 1A according to the present embodiment will be described.

[0055] like Figure 1 As shown, the optical device 1A comprises: a light source 2, a light guide plate 10 for guiding light incident from the light source 2 and emitting the light from an emission surface 12, and a plurality of light path deflecting units 21 (a plurality of units) arranged on the light guide plate 10. The plurality of light path deflecting units 21 are composed of a plurality of light path deflecting unit groups 21a / 21b / 21c... (a plurality of deflecting units), and form a stereoscopic image I in space by deflecting the light path of the guided light and emitting the light.

[0056] The light source 2 is composed of a plurality of light emitting diodes (LEDs) 2a, and the light emitted from each light emitting diode (LED) 2a is adjusted by the incident light adjusting unit 3 and incident on the incident surface 11 of the light guide plate 10. In the present embodiment, the light source 2 is composed of a plurality of LEDs, but may be composed of a single LED.

[0057] The incident light adjustment portion 3 has a plurality of lenses 3a corresponding one-to-one to the light emitting diodes (LEDs) 2a. Each lens 3a reduces or increases the expansion of the light in the xy plane described later in the direction of the optical axis of the emitted light of the corresponding light emitting diode (LED) 2a, or keeps it unchanged. As a result, the lens 3a makes the emitted light from the light emitting diode (LED) 2a close to parallel light, or guides the light in the entire area inside the light guide plate 10. The expansion angle of the light guided by the light guide plate 10 can be less than 5°, preferably less than 1°. As another structure for reducing the expansion angle of the light in the xy plane within the light guide plate 10, for example, the incident light adjustment portion 3 may also have a mask having an opening smaller than a specified width in the x-axis direction.

[0058] In this embodiment, if Figure 2 As shown, the optical axis of the emitted light of the light emitting diode (LED) 2a forms an angle θ with the emission surface 12. For example, the narrow angle θ formed by the optical axis of the emitted light of the light emitting diode (LED) 2a and the emission surface 12 is about 20°. As a result, compared with the case where the optical axis of the incident light is parallel to the y-axis, even when the incident light directed to the light guide plate 10 is close to parallel light, it can be repeatedly reflected by the emission surface 12 and the back surface 13, and the amount of light guided in the light guide plate 10 is increased. Therefore, compared with the case where the optical axis of the incident light is parallel to the y-axis, the amount of light incident on the optical path deflecting unit 20 can be increased.

[0059] The light guide plate 10 is formed of a transparent resin material having a relatively high refractive index. As a material forming the light guide plate 10, for example, polycarbonate resin (PC), polymethyl methacrylate resin (PMMA) glass, etc. can be used.

[0060] The light guide plate 10 includes an incident surface 11 on which light from the light source 2 is incident, an exit surface 12 which is the surface of the light guide plate 10 and from which light is exited, and a rear surface 13 on which a light path deflecting unit 21 is formed.

[0061] In the present embodiment, light is emitted from the emission surface 12 of the light guide plate 10, and a stereoscopic image I is formed in space by the emitted light. The stereoscopic image I is recognized three-dimensionally by the observer. The stereoscopic image I refers to an image recognized as existing at a position different from the emission surface 12 of the light guide plate 10. For example, the stereoscopic image I also includes a two-dimensional image recognized at a position separated from the emission surface 12 of the light guide plate 10. That is, the stereoscopic image I is a concept that includes not only an image recognized as a three-dimensional shape but also an image of a two-dimensional shape recognized at a position different from the optical device 1A. In the present embodiment, the stereoscopic image I is described as a real image located closer to the positive side of the z-axis than the emission surface 12, but the stereoscopic image I may also be a virtual image located closer to the negative side of the z-axis than the emission surface 12.

[0062] In the description of this embodiment, an orthogonal coordinate system formed by the x-axis, y-axis, and z-axis is sometimes used. In this embodiment, the z-axis is defined as a direction perpendicular to the emission surface 12, and the direction from the back surface 13 to the emission surface 12 is defined as the positive direction of the z-axis. In addition, the y-axis is defined as a direction perpendicular to the incident surface 11, and the direction in which light travels in the light guide plate 10 is defined as the positive direction of the y-axis. The x-axis is defined as a direction perpendicular to the y-axis and the z-axis, and Figure 1 The direction from the left side to the right side is defined as the positive direction of the x-axis. Sometimes the surface parallel to the xy plane is called the xy plane, the surface parallel to the yz plane is called the yz plane, and the surface parallel to the xz plane is called the xz plane.

[0063] A plurality of optical path deflecting units 21 are formed on the back surface 13 of the light guide plate 10. The plurality of optical path deflecting units 21 deflect the optical path of the light guided in the light guide plate 10 and emit the light, thereby spatially forming a stereoscopic image I as an image. The plurality of optical path deflecting units 21 are two-dimensionally arranged in a matrix shape in the xy plane at different positions. The optical path deflecting units 21 are composed of, for example, prisms.

[0064] exist Figure 2 In the embodiment, light emitted from the light source 2 passes through the incident light adjustment unit 3 and enters from the incident surface 11 of the light guide plate 10. The light incident on the light guide plate 10 is totally reflected and guided between the exit surface 12 and the back surface 13 of the light guide plate 10. Then, the light path deflection unit 21 breaks the total reflection condition, deflects the light path to a specified direction, and emits the light from the exit surface 12.

[0065] Next, the structure and function of the optical path deflecting unit 21 will be described.

[0066] based on Figure 1 , Figure 3 ,as well as Figure 4 , a structure for forming a stereoscopic image I by the optical device 1A will be described. Figure 3 1 is a plan view showing a structure for forming a stereoscopic image I by the optical device 1A. Figure 4 1 is a front view showing an example of a stereoscopic image I formed by the optical device 1A.

[0067] like Figure 1 As shown, for example, it is possible to consider a case where the optical device 1A images, for example, an inner oblique line ring mark formed by the surface image FI as a stereoscopic image I on a stereoscopic image imaging plane parallel to the xz plane ( Figure 4 ).

[0068] In the optical device 1A, it is preferred that the expansion of the light propagating in the light guide plate 10 in the yz plane is large. Therefore, the incident light adjustment portion 3 does not reduce the expansion angle of the light from the light source 2 in the yz plane. In other words, the incident light adjustment portion 3 does not actually affect the expansion angle of the light from the light source 2 in the yz plane.

[0069] For example, the lens 3a of the incident light adjusting unit 3 may be a convex cylindrical lens having a curvature in the xy plane and substantially no curvature in the yz plane. The cylindrical lens may be formed of convex lenses on both sides.

[0070] A plurality of light path deflection unit groups 21a / 21b / 21c... are arranged on the back surface 13 of the light guide plate 10 as the light path deflection unit group 21. The plurality of light path deflection unit groups 21a / 21b / 21c... are respectively formed by a plurality of prisms arranged in a direction parallel to the x-axis. For example, the light path deflection unit group 21a is composed of a plurality of prisms P21a. Similarly, the light path deflection unit group 21b is composed of a plurality of prisms P21b. The light path deflection unit group 21c is composed of a plurality of prisms P21c.

[0071] For example, the prism P21a deflects the incident light and expands it in a direction parallel to the xy plane, and then emits it from the emission surface 12. The light beam emitted from the emission surface 12 through the prism P21a actually intersects the stereoscopic image imaging surface in a line. Figure 1 and Figure 3 As shown, two light beams are emitted from the emission surface 12 through the prism P21a. The emitted two light beams intersect with the stereoscopic image imaging surface at line 31a1 and line 31a2. Figure 1As shown, any prism P21a included in the optical path deflection unit group 21a is also the same as other prisms P21a, so that the light beam that intersects the stereoscopic image imaging plane with the line 31a1 and the line 31a2 is emitted from the emission surface 12. The line 31a1 and the line 31a2 are actually located in a plane parallel to the xy plane, and a part of the stereoscopic image I is imaged. In this way, the line image LI of the line 31a1 and the line 31a2 is imaged using the light from the multiple prisms P21a belonging to the optical path deflection unit group 21a. The light that forms the image of the line 31a1 and the line 31a2 can be provided by at least two prisms P21a / P21a of the optical path deflection unit group 21a arranged at different positions along the x-axis direction.

[0072] Each of the plurality of prisms P21a belonging to the optical path deflecting unit group 21a expands the light incident on each prism P21a in the x-axis direction within a plane parallel to the emission surface 12 so as to have an intensity distribution corresponding to the image of the line 31a1 and the line 31a2, and emits the light from the emission surface 12. Thus, the light from the plurality of prisms P21a belonging to the optical path deflecting unit group 21a and arranged along the x-axis direction becomes light imaged as the image of the line 31a1 and the line 31a2.

[0073] Likewise, if Figure 1 As shown, the multiple prisms P21b belonging to the optical path deflection unit group 21b each deflect the incident light, expand it in a direction parallel to the xy plane, and emit three light beams from the emission surface 12. The three light beams emitted from the emission surface 12 intersect the stereoscopic image imaging surface at lines 31b1, 31b2, and 31b3. Moreover, any prism P21b included in the optical path deflection unit group 21b also makes the light beams intersecting the stereoscopic image imaging surface at lines 31b1 / 31b2 / 31b3 be emitted from the emission surface 12 in the same manner as other prisms P21b. In this way, the multiple prisms P21b belonging to the optical path deflection unit group 21b each expand the light incident to the prism P21b in the x-axis direction in a plane parallel to the emission surface 12 so as to have an intensity distribution corresponding to the image of lines 31b1 / 31b2 / 31b3, and emit it from the emission surface 12. Thus, light from the plurality of prisms P21b belonging to the optical path deflection unit group 21b and arranged along the x-axis direction forms an image of lines 31b1 / 31b2 / 31b3. Lines 31b1 / 31b2 / 31b3 are actually located in a plane parallel to the xy plane, forming a part of the stereoscopic image I.

[0074] Here, the imaging position of the line 31b1 / 31b2 / 31b3 and the imaging position of the line 31a1 / 31a2 are different in the z-axis direction within the stereoscopic image imaging plane.

[0075] like Figure 1As shown, similarly, the multiple prisms P21c belonging to the optical path deflection unit group 21c each deflect the incident light, expand it in a direction parallel to the xy plane, and emit two light beams from the emission surface 12. The two light beams emitted from the emission surface 12 intersect the stereoscopic image imaging surface at the line 31c1 and the line 31c2. Moreover, any prism P21c included in the optical path deflection unit group 21c is also the same as other prisms P21c, so that the light beam intersecting the stereoscopic image imaging surface at the line 31c1 / 31c2 is emitted from the emission surface 12. In this way, the multiple prisms P21c belonging to the optical path deflection unit group 21c each expand the light incident to the prism P21c in the x-axis direction in a plane parallel to the emission surface 12 to have an intensity distribution corresponding to the image of the line 31c1 / 31c2, and emit it from the emission surface 12. Thus, light from the plurality of prisms P21c belonging to the optical path deflection unit group 21c and arranged along the x-axis direction forms an image of line 31c1 / 31c2. Line 31c1 / 31c2 is actually located in a plane parallel to the xy plane, forming a part of the stereoscopic image I.

[0076] Here, the imaging position of the line 31c1 / 31c2, the imaging position of the line 31b1 / 31b2 / 31b3, and the imaging position of the line 31a1 / 31a2 are different in the z-axis direction within the stereoscopic image imaging plane.

[0077] exist Figure 1 As described above, the imaging position of line 31c1 / 31c2, the imaging position of line 31b1 / 31b2 / 31b3, and the imaging position of line 31a1 / 31a2 are different in the z-axis direction within the stereoscopic image imaging plane and are viewed separately. However, in reality, the optical path deflection unit group 21a / 21b / 21c can be composed of more first optical path deflection unit groups than the optical path deflection unit groups 21a / 21b / 21c..., and the y-axis spacing of the optical path deflection unit groups 21a / 21b / 21c can be reduced. Alternatively, even if the optical path deflection unit group 21a / 21b / 21c is separated in the y-axis direction, by adjusting the optical path deflection angle of each prism P21a / P21b / P21c, the imaging position of line 31a1 / 31a2, the imaging position of line 31b1 / 31b2 / 31b3, and the imaging position of line 31c1 / 31c2 can be made close to each other in the z-axis direction. As a result, Figure 4 As shown, as a stereoscopic image I, a surface image FI of an inner oblique line ring mark can be seen.

[0078] In this way, the optical device 1A can image the light beams into a plane image FI by gathering the light beams from the plurality of prisms P21a / P21b / P21c of the two-dimensionally arranged optical path deflection unit group 21a / 21b / 21c..., and provide it to the space on the observer side. Therefore, the observer can recognize the stereoscopic image I formed by the plane image FI from a wide range of positions along the y-axis direction.

[0079] (Shape of the optical path deflection unit group)

[0080] based on Figure 5 , the shapes of the prisms P21a / P21b / P21c... of the optical path deflecting unit group 21a / 21b / 21c... for imaging the surface image FI are described.

[0081] Figure 5 1A is a perspective view showing a structure of an example of a prism P21a formed on the light guide plate 10 of the optical device 1A.

[0082] As shown in the figure, the prism P21a of the optical path deflection unit group 21a is formed into a shape with a mountain-shaped cross-section, for example, a part of a circular ring cut off, and has reflection surfaces f1 / f2 / f3 / f4 / f5. The above-mentioned reflection surfaces f1 / f2 / f3 / f4 / f5 are an example of an optical surface used as a deflection surface for deflecting the light path, and are formed by curved surfaces facing different directions. As described above, the optical axis of the light emitting diode (LED) 2a and the emitting surface 12 of the light guide plate 10 are set to be inclined only at an angle θ in the yz plane. Therefore, compared with the case where the optical axis of the incident light is parallel to the y-axis, even if the incident light directed to the light guide plate 10 is close to parallel light, it can be repeatedly reflected by the emitting surface 12 and the back surface 13, and the amount of light guided in the light guide plate 10 is increased. Therefore, compared with the case where the optical axis of the incident light is parallel to the y-axis, the amount of light incident on the reflection surfaces f1 / f2 / f3 / f4 / f5 can be increased.

[0083] The reflection surface f1 is an upward inclined surface that is curved into an arc shape in a direction parallel to the light L1 guided on the light guide plate 10. The light L1 incident on the reflection surface f1 is emitted at an emission angle different from that of the emission surface 12 according to the incident position of the reflection surface f1. As a result, Figure 2As shown, the reflecting surface f1 causes the light L1 incident on the reflecting surface f1 to expand toward the range of, for example, the edge 31 in the stereoscopic image I. The edge 31 is a side parallel to the y-axis. The reflected light from the reflecting surface f1 is directed toward the direction where the edge 31 exists, and the light from the reflecting surface f1 toward the direction where the edge 31 does not exist actually does not exist. Therefore, the reflected light from the reflecting surface f1 is actually distributed only within the angle from the reflecting surface f1 toward the edge 31 in the yz plane. In this way, in the yz plane, the reflecting surface f1 modulates the intensity of the incident light within the angular direction and emits it. Because the reflecting surface f1 is a curved surface, even when the incident light L1 incident on the reflecting surface f1 is parallel light, it is possible to provide light for forming a line image of the drawn image.

[0084] like Figure 5 As shown, in the prism P21a, the reflection surfaces f2 / f3 extend on an arc across the reflection surface f1 in a donut-shaped cross-section having a mountain shape, and are inclined surfaces halfway up the slope of the mountain like the reflection surface f1. Figure 1 As shown, the light L1 incident on the reflection surface f2 / f3 is reflected, and the reflected light is spread to the range of the line 31a1 and the line 31a2 of the three-dimensional image I. Figure 1 As shown, there is no line between the line 31a1 and the line 31a2 of the stereoscopic image I due to the existence of the reflection surface f1.

[0085] like Figure 5 As shown, in addition, the reflection surface f4 / f5 is formed by an upward inclined surface formed by a variable curve formed in the middle of the reflection surface f4 / f5. Figure 1 As shown, due to the existence of the reflection surfaces f4 / f5, for example, the line 31c1 and the line 31c2 of the stereoscopic image I can be imaged.

[0086] Thus, for example, by forming the prism P21a into the shape of the reflection surfaces f1 to f5, the lines 31, 31a1 / 31a2, 31b1 / 31b2 / 31b3, and 31c1 / 31c2 serving as the basis of the surface image FI of the stereoscopic image I can be imaged.

[0087] (Examples of use and arrangement of optical path deflection unit group)

[0088] Below, based on Figure 6 , the usage examples and arrangement examples of the optical path deflection unit group 21a / 21b / 21c... are explained.

[0089] Figure 6 2 is a diagram showing an example of use and arrangement of the optical path deflection unit group 21a / 21b / 21c... Figure 6As shown, for example, as the optical path deflection unit group 21a / 21b / 21c, the following structure is illustrated, that is, the triangular prism P21a / P21b / P21c is respectively arranged in a matrix of three rows and two columns, and is arranged with a slight gap. This structure is an example, and other structures can be adopted. For example, as the optical path deflection unit group 21a / 21b / 21c, the triangular prism P21a / P21b / P21c can also be arranged in a matrix of three rows and three columns.

[0090] (Structure of light guide plate for improving grayscale expression)

[0091] Next, use Figure 7 The detailed structure of the light guide plate 10 for improving grayscale expression will be described below.

[0092] Figure 7 2 is a diagram showing how the light emitted from the plurality of light path deflection units 21 is imaged in the air. Fig.16 For explanation. Fig.16 In the embodiment, light is emitted from all the light path deflection unit groups 200, and an image is formed in the air. The grayscale at this time is 100 grayscale. Figure 7 The structure shown is based on the production of Fig.16 The structure shown is 50% grayscale for the purpose of designing the structure. Figure 7 In FIG. 1 , the solid line indicates the case where light is emitted, and the dotted line schematically indicates the case where light is not emitted.

[0093] The light guide plate 10 includes a plurality of light path deflecting portions 21 arranged in a matrix. Figure 7 The multiple light path deflection parts 21 include multiple light path deflection part groups 21a / 21b / 21c... (not shown) that each deflects the light incident on the light guide plate 10 in multiple directions and emits it. Here, the description focuses on the adjacent first light path deflection part 21 and the second light path deflection part 21 among the multiple light path deflection parts 21.

[0094] The first optical path deflection unit 21 includes a first prism that deflects light toward a first angle range in order to display a plurality of points of a line or a plane of intermediate grayscale constituting a stereoscopic image. The first optical path deflection unit 21 does not include a second prism that deflects light toward a second angle range adjacent to the first angle range. In addition, the first optical path deflection unit 21 includes a third prism that deflects light toward a third angle range adjacent to the second angle range. The second optical path deflection unit 21 does not include the first prism, includes the second prism, and does not include the third prism.

[0095] The difference between the first angle range and the second angle range is preferably within 6 degrees, and further preferably within 3 degrees. This is because, assuming that the distance between the eyes of an average adult is about 6 cm, the angle formed by the position 50 cm apart and the eyes is 6.8 degrees, so it is less than 6.8 degrees. The reason why it is within 3 degrees is that by setting it to 50% of 6 degrees, that is, 3 degrees, it can be applied even if the distance is far and the distance between the eyes is reduced. The difference between the second angle range and the third angle range, and the angle ranges thereafter, can also be considered to be the same as the above description.

[0096] exist Figure 7 In the light guide plate 10, the first light path deflecting portion 21 and the second light path deflecting portion 21 are periodically and alternately arranged. Figure 8 shown.

[0097] Figure 8 Yes Description Figure 7 Figure 1 shows the main components of the . Figure 8 Four light deflection units 21P, 21Q, 21R, and 21S are shown in an enlarged manner.

[0098] The light deflection unit 21P deflects light in directions with reference to R1, R3, R5, and R7. That is, the light deflection unit 21P includes a plurality of prisms that deflect light in directions with reference to R1, R3, R5, and R7. However, the light deflection unit 21P does not deflect light in directions with reference to R2, R4, R6, R8, and R10. That is, the light deflection unit 21P does not include a prism that deflects light in directions with reference to R2, R4, R6, R8, and R10.

[0099] The light deflection unit 21Q deflects light in directions with reference to R2, R4, R6, R8, and R10. That is, the light deflection unit 21Q includes a plurality of prisms that deflect light in directions with reference to R2, R4, R6, R8, and R10. However, the light deflection unit 21Q does not deflect light in directions with reference to R1, R3, R5, R7, and R9. That is, the light deflection unit 21Q does not include a prism that deflects light in directions with reference to R1, R3, R5, R7, and R9.

[0100] The light deflection unit 21R deflects light in directions with reference to R1, R3, R5, and R7. That is, the light deflection unit 21R includes a plurality of prisms that deflect light in directions with reference to R1, R3, R5, and R7. However, the light deflection unit 21R does not deflect light in directions with reference to R2, R4, R6, R8, and R10. That is, the light deflection unit 21R does not include a prism that deflects light in directions with reference to R2, R4, R6, R8, and R10.

[0101] The light deflection unit 21S deflects light in directions with reference to R2, R4, R6, and R8. That is, the light deflection unit 21S includes a plurality of prisms that deflect light in directions with reference to R2, R4, R6, and R8. However, the light deflection unit 21S does not deflect light in directions with reference to R1, R3, R5, and R7. That is, the light deflection unit 21S does not include a prism that deflects light in directions with reference to R1, R3, R5, and R7. Fig. 9 , which is further explained.

[0102] Fig. 9 2 is a diagram showing a light emitting pattern on the light guide plate 10. On the light guide plate 10, a plurality of light path deflecting portions 21 are arranged in a matrix. Fig. 9 In the figure above, the position of the light path deflection part that deflects in a specified direction (direction A) is marked. Direction A can be considered as a reference Figure 8 The directions described above are referenced to R1, R3, R5, R7, and R9. Fig. 9 In the figure below, the position of the light path deflection part that deflects in a specified direction (direction B) is marked. Direction B can be considered as a reference Figure 8 In the above description, R2, R4, R6, R8, and R10 are used as reference directions. In this way, each of the plurality of light path deflection units 21 can change the selection method (elimination method) of the prisms when the viewing angle gradually changes. As a result, the light emitting pattern on the light guide plate 10 changes in the directions A and B.

[0103] By having the structure as described, Figure 7 As shown in FIG. 1 , the light guide plate 10 displays a predetermined image in space and reduces the number of image points in the air to 50%. As a result, the light guide plate 10 can produce Fig.16 50% of the structure (100 grayscale) shown in the figure is 50 grayscale. In this way, the light guide plate 10 improves the grayscale performance compared with the past. An example is as follows Fig.10 shown.

[0104] Fig.10 An example of a stereoscopic image with improved grayscale expression displayed in space using the light guide plate 10 is shown. As shown in the figure, the stereoscopic image displayed in space maintains a three-dimensional sense and has grayscale on each surface. In addition, on the light guide plate 10, the prism selection method (elimination method) can be changed each time the viewing angle is gradually changed slightly. As a result, the light guide plate 10 can also have a further effect of reducing the number of processing times and shortening the processing time.

[0105] [Second embodiment (50 grayscale)]

[0106] Next, a second embodiment of the present invention will be described. For the sake of convenience, the same reference numerals are used for components having the same functions as those described in the above embodiment, and their descriptions are not repeated. This also applies to other embodiments described later.

[0107] use Fig.11 etc., explaining the structure for producing 50 gray levels. Fig.11 1 is a diagram showing a light emission pattern on the light guide plate 10 when the grayscale is assumed to be 100. Fig.12 is a diagram showing a light emission pattern on the light guide plate 10 when 50 gray levels are assumed. Fig.11 , Fig.12 In the embodiment, a plurality of light path deflecting units 21 are arranged in a matrix.

[0108] like Fig.11 As shown in FIG. 1 , when the grayscale is assumed to be 100, the light path deflection unit 21 deflects the light respectively without limiting the specified direction. Fig.11 In FIG. 1 , all the optical path deflecting units 21 arranged in a matrix are marked with symbols.

[0109] On the other hand, assuming 50 gray levels, as shown in Fig. 9 In the above description, the optical path deflecting units 21 deflect light in a specified direction such as the direction with reference to R1, R3, R5, and R7, or the direction with reference to R2, R4, R6, R8, and R10. Fig.12 The positions of the marks in the upper figure (configuration A) and the lower figure (configuration B) are different.

[0110] The following will be described in more detail. Fig.12 In FIG. 1 , a matrix with eight rows and eight columns is described as an example. When the position of the optical path deflection unit 21 of the matrix is ​​expressed by (row number, column number), for example, (1, 1) and (2, 2) are marked in configuration A. (1, 2) and (2, 1) are marked in configuration B. The description of other positions of the matrix is ​​omitted, but as shown in the figure, Fig.12 The positions of the marks in the upper figure (configuration A) and the lower figure (configuration B) are alternating. By making configuration A and configuration B alternate, the light guide plate 10 reduces the number of imaging points in the air to 50%, producing Fig.11 50 gray of 50% of the structure shown (100 gray).

[0111] use Fig.13 , other structures that produce 50 gray levels are explained. Fig.13 1 is a diagram showing a light emission pattern on the light guide plate 10 when 50 grayscales are assumed.

[0112] Fig.12 The configurations A and B are different. Fig.13 In configuration A, (1, 1) and (2, 1) are marked. In configuration B, (1, 2) and (2, 2) are marked. That is, in Fig.13 The positions marked with marks in the upper figure (configuration A) and the lower figure (configuration B) are alternating. The description of other positions of the matrix is ​​omitted, but as shown in the figure, by making configuration A and configuration B in an alternating position relationship, the light guide plate 10 reduces the number of imaging points in the air to 50%, generating Fig.11 50 gray of 50% of the structure shown (100 gray).

[0113] Thus, according to Fig.12 , Fig.13 The structure of the light guide plate 10 can display a specified image in space and generate Fig.11 50% of the structure (100 grayscale) shown in the figure is 50 grayscale. In this way, the light guide plate 10 makes the grayscale expression more improved than before. It should be noted that, although not shown in the figure, in order to produce Fig.11 The 50 gray scale of 50% of the structure (100 gray scale) shown may be a structure in which (1, 2) and (2, 2) are marked in configuration A, and (1, 1) and (2, 1) are marked in configuration B.

[0114] [Third embodiment (25 grayscale)]

[0115] Next, use Fig.14 , Fig.15 , explaining the structure that produces 25 gray levels. Fig.14 and Fig.15 2 are diagrams showing light emission patterns on the light guide plate 10 when the grayscale is assumed to be 25. Fig.14 and Fig.15 In the embodiment, a plurality of optical path deflecting units 21 are arranged in a matrix. In the following description, the positions of the optical path deflecting units 21 in the matrix are also represented by (row number, column number).

[0116] First, attention is paid to the first to fourth optical path deflecting units 21 among the plurality of optical path deflecting units 21 .

[0117] The first optical path deflecting unit 21 includes a first prism that deflects light into a first angle range in order to display a plurality of points of a line or a plane of intermediate grayscale constituting a stereoscopic image. The first optical path deflecting unit 21 does not include a second prism that deflects light into a second angle range adjacent to the first angle range. The second optical path deflecting unit 21 does not include a first prism but includes a second prism.

[0118] Furthermore, the first optical path deflecting unit 21 and the second optical path deflecting unit 21 do not include a third prism for deflecting light into a third angle range adjacent to the second angle range, and do not include a fourth prism for deflecting light into a fourth angle range adjacent to the third angle range.

[0119] Furthermore, the light guide plate 10 further includes: a third light path deflecting unit 21 including the third prism but excluding the first prism, the second prism, and the fourth prism; and a fourth light path deflecting unit 21 including the fourth prism but excluding the first to third prisms.

[0120] The first to fourth light path deflecting units 21 configured in this way are periodically arranged on the light guide plate 10 .

[0121] Fig.14 There are configurations A to D, and the explanation will focus on (1, 1), (1, 2), (2, 1), and (2, 2) of configurations A to D. In configuration A, only (1, 1) is marked. In configuration B, only (1, 2) is marked. In configuration C, only (2, 1) is marked. In configuration D, only (2, 2) is marked. The explanation of other positions in the matrix is ​​omitted, but as shown in the figure, Fig.14 In configurations A to D, the positions marked with labels change periodically.

[0122] In this way, the plurality of optical path deflecting units 21 can change the selection method (elimination method) of the prisms each time the viewing angle is gradually and slightly changed. For example, in configuration A, light is deflected only in the directions of R1 and R5, in configuration B, light is deflected only in the directions of R2 and R6, in configuration C, light is deflected only in the directions of R3 and R7, and in configuration D, light is deflected only in the directions of R4 and R8.

[0123] By having the above structure, the light guide plate 10 displays a predetermined image in space and reduces the number of image points in the air to 25%. As a result, the light guide plate 10 can produce Fig.11 25 grays of 25% of the structure shown (100 grays).

[0124] Fig.14 The configurations A to D are different. Fig.15 In the embodiment, symbols are respectively given in configuration A (1, 1), configuration B (2, 1), configuration C (1, 2), and configuration D (2, 2). In this way, even if the selection method (elimination method) of the prisms is changed, the light guide plate 10 can generate Fig.11 25 grays of 25% of the structure shown (100 grays).

[0125] [Fourth embodiment (variation)]

[0126] In this embodiment, a configuration that produces richer grayscale expressions other than 50% and 25% is described.

[0127] In reference Figure 12 to Figure 15 In the described embodiment, "2×2" is regarded as a unit of the matrix. However, for example, when "3×3" is regarded as a unit of the matrix, nine (3×3) layers of grayscale expression can be generated. In addition, when "3×2" is regarded as a unit of the matrix, six (3×2) layers of grayscale expression can be generated. In addition, even when "2×2" is regarded as a unit, 75 grayscales can be generated.

[0128] Thus, in this embodiment, as in other embodiments, each time the viewing angle is gradually changed slightly, the selection method (elimination method) of the prisms of the optical path deflecting unit 21 can be changed. This makes it possible to realize a light guide plate that displays a stereoscopic image with improved grayscale expression in space.

[0129] In addition, in conjunction with the various embodiments described above, the prisms included in one optical path deflection unit 21 may include at least one prism that is different from the other prisms in at least one of length and height. Fig.18 For example, when the length of the prism is halved, the brightness is reduced to 50% and the grayscale is 50%. Similarly, when the height (that is, the width) of the prism is halved, the brightness is reduced to 50% and the grayscale is 50%.

[0130] Therefore, for example, when using Fig.12 The structure produces 50 grayscales based on the fact that when the length of all prisms is half, the brightness is halved, so 25 grayscales can be produced. Fig.14 The structure produces 25 gray levels based on making the length of all prisms half, the brightness is halved, so the gray level is also halved.

[0131] In this way, each time the viewing angle is gradually slightly changed, the selection method (elimination method) of each prism of the optical path deflection unit 21 can be changed. In addition, a structure of changing at least one of the length and height of the prism can be combined. In this case, a structure in which the prism is shortened to 50 μm in length and then the height of the prism is reduced (the width of the prism is reduced) can be adopted. By adopting the above structure, a light guide plate that displays a stereoscopic image with further improved grayscale expression in space can be provided.

[0132] [Applications in display devices, input devices, entertainment equipment, etc.]

[0133] A display device including the light guide plate 10 of each embodiment and a light source (such as a light emitting diode) for irradiating incident light to the light guide plate 10 is also included in the technical scope of the present invention.

[0134] In addition, the display device and the sensor unit 50 (see FIG. 5 ) for detecting an object (such as a human finger) that is close to the stereoscopic image I formed in space or exists near the stereoscopic image I are provided. Figure 1 The sensor unit 50 may be a well-known sensor such as a limited reflection sensor that detects the presence of an object when the object is located at a predetermined detection position.

[0135] In addition, various devices having the display device are also included in the technical scope of the present invention. Examples of the above-mentioned devices include entertainment equipment (devices and machines used in game centers, etc.), toys, vehicle-mounted equipment, and household appliances.

[0136] The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical claims. Embodiments obtained by appropriately combining the technical claims disclosed in different embodiments are also included in the technical scope of the present invention.

[0137] Description of Reference Numerals

[0138] 1A optical device; 2 light source; 3 incident light adjustment unit; 3a lens; 10 light guide plate; 11 incident surface; 12 exit surface; 13 back surface; 21 light path deflection unit; 21, 21a, 21a / 21b / 21c, 21b, 21c, 200 light path deflection unit group; 21P, 21Q, 21R, 21S light deflection unit; 50 sensor unit.

Claims

1. A light guide plate that displays a predetermined image as a real image or a virtual image in space, wherein: It includes a plurality of units arranged in a matrix. Each unit includes a plurality of deflection parts that deflect the light incident on the light guide plate in a plurality of directions and emit the light. In order to display multiple points of intermediate gray lines or surfaces constituting the image, the first unit and the second unit are periodically configured, the first unit includes a first deflection unit that deflects light toward a first angle range but does not include a second deflection unit that deflects light toward a second angle range adjacent to the first angle range, and the second unit does not include the first deflection unit but includes the second deflection unit.

2. The light guide plate according to claim 1, wherein: The first unit includes a third deflecting portion that deflects light toward a third angle range adjacent to the second angle range, and the second unit does not include the third deflecting portion.

3. The light guide plate according to claim 1 or 2, characterized in that: The first units and the second units are arranged alternately.

4. The light guide plate according to claim 1, wherein: The first unit and the second unit do not include a third deflection unit for deflecting light into a third angle range adjacent to the second angle range, and do not include a fourth deflection unit for deflecting light into a fourth angle range adjacent to the third angle range. The light guide plate further includes: a third unit including the third deflecting unit but not including the first deflecting unit, the second deflecting unit, and the fourth deflecting unit; a fourth unit including the fourth deflecting unit but not including the first deflecting unit to the third deflecting unit, The first to fourth units are periodically configured.

5. The light guide plate according to claim 1, wherein: The plurality of deflecting units include at least one deflecting unit having at least one of a length and a height different from the others.

6. A display device, characterized in that: have: The light guide plate according to any one of claims 1 to 5; A light source irradiates incident light toward the light guide plate.

7. An input device, characterized in that: have: The display device according to claim 6; a sensor portion for detecting an object.

8. A device, characterized in that A display device according to claim 6.

Images