REPRESENTATION METHODS

Abstract

A viewer is enabled to visually perceive a stereoscopic image with a stereoscopic effect even when an optical element is transparent. A method for displaying a stereoscopic image using a display device equipped with a transparent optical element comprises: emitting light, which is to be perceived by a viewer as a stereoscopic image (11), from an optical element; and displaying the stereoscopic image (11) on a stereoscopic image formation plane (P1) that is not parallel to an exit surface (21) of the optical element. In the display method, the viewer can visually perceive one side of the rear surface of the display device through the optical element.

Description

TECHNICAL AREA

[0001] The present invention relates to a display method by which a viewer can perceive a stereoscopic image. STATE OF THE ART

[0002] As a display device for displaying a stereoscopic image, for example, a display device as described in Patent Document 1 is known.

[0003] The display device disclosed in Patent Document 1 includes: a light guide plate; a light source disposed at one end of the light guide plate; a first display pattern including a plurality of first prisms formed on the back surface of the light guide plate; and a second display pattern including a plurality of second prisms formed on the back surface of the light guide plate. The first display pattern forms a first image on the front surface side of the light guide plate with the plurality of first prisms, and the second display pattern forms a second image on the front surface side of the light guide plate with the plurality of second prisms.

[0004] With this configuration, by appropriately adjusting the shapes (mainly the reflecting surfaces) of the first prism and the second prism of the respective display patterns, it is possible, for example, to create a first image visually perceived by the viewer's right eye and a second image visually perceived by the viewer's left eye. This allows the viewer to perceive a stereoscopic image in a natural state without the viewer having to perform any unnatural movement for merging. DOCUMENT FROM THE PRIOR ART PATENT DOCUMENT Patent Document 1: Japanese Unexamined Patent Publication No. JP 2012-118378 A Patent Document 2: Japanese Unexamined Patent Publication No. JP 2011-175297 A

[0005] Further prior art documents are US 2007 / 0 109 505 A1, WO 2017 / 017 981 A1, and WO 2016 / 056 345 A1. OVERVIEW OF THE INVENTION TASK TO BE SOLVED BY THE INVENTION

[0006] However, in the display device described in Patent Document 1, the light guide plate as an optical element is transparent, and a stereoscopic image is displayed on a plane parallel to the exit surface of the light guide plate. This gives the viewer the impression that the light-emitting surface of the light guide plate is illuminated. This poses a problem in that the viewer hardly perceives the stereoscopic effect of the stereoscopic image.

[0007] An object of one aspect of the present invention is to realize a stereoscopic image display method by which a viewer can visually perceive a stereoscopic image having a stereoscopic effect when the optical element is transparent. MEANS TO SOLVE THE TASK

[0008] In order to achieve the above-described object, a display method according to claim 1 is provided. EFFECT OF THE INVENTION

[0009] According to one aspect of the present invention, when the optical element is transparent, an effect can be achieved that a viewer can visually perceive a stereoscopic image with a stereoscopic effect. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a configuration of a display device according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view showing the configuration of the display device. Fig. 3 is a plan view showing the configuration of the display device. Fig. Fig. 4(a) is a plan view showing a configuration of a light path changing unit provided in the display device, and Fig. 4(b) is a perspective view showing a configuration of a reflector for changing the light path. Fig. 5 is a perspective view showing an arrangement of reflectors in the light path changing unit. Fig. 6 is a perspective view showing a method of generating a plane image by the light path changing unit. The Fig. 7(a) to 7(d) are perspective views showing display examples using the display device. The Fig. 8(a) to 8(d) are perspective views showing other display examples using the display device. Fig. 9 is a perspective view showing a configuration of a display device according to a second embodiment of the present invention. Fig. 10 is a perspective view illustrating a configuration of a two-dimensional image display device included in the display device. Fig. 11 is a plan view showing a configuration of a light path changing unit included in the two-dimensional image display apparatus. Fig. 12 is a perspective view showing a display example using the display device. The Fig. 13(a) and Fig. 13(b) are diagrams illustrating display examples using an optical element according to a third embodiment of the present invention. EMBODIMENTS OF THE INVENTION [First Embodiment]

[0010] A display device 1A and a display method for the display device 1A according to the first embodiment of the present invention will be described in detail with reference to FIG. Fig. 1 to 8 described. (Configuration of the display device 1A)

[0011] The configuration of the display device 1A is described with reference to the Fig. 1 to 5.

[0012] Fig. Fig. 1 is a perspective view showing the configuration of the display device 1A. Fig. Fig. 2 is a cross-sectional view showing the configuration of the display device 1A. Fig. Fig. 3 is a plan view showing the configuration of the display device 1A. In the following, for convenience of description, a positive X direction in Fig. 1 as the forward direction, a negative X direction as the backward direction, a positive Y direction as the right direction, a negative Y direction as the left direction, a positive Z direction as the upward direction and a negative Z direction as the downward direction.

[0013] As in the Fig. 1 to 3, the display device 1A comprises a light source 10 and a light guide plate (optical element) 20.

[0014] The light source 10 is an element for irradiating the light guide plate 20 with light and is formed, for example, by a light-emitting diode (LED). The light source 10 may have a configuration including one light-emitting diode or a configuration including a plurality of light-emitting diodes.

[0015] The light guide plate 20 is a member that guides incident light from the light source 10. The shape of the light guide plate 20 is not limited; in the present embodiment, it has a substantially rectangular parallelepiped shape. The light guide plate 20 is made of a transparent resin material with a relatively high refractive index. As a material for forming the light guide plate 20, for example, a polycarbonate resin, polymethyl methacrylate resin, or the like can be used. In the present embodiment, the light guide plate 20 is made of a polymethyl methacrylate resin. Since the light guide plate 20 is transparent, the viewer can observe the rear surface side of the display device 1A through the light guide plate 20 in the present embodiment.Thereby, in the display device 1A, the viewer can perceive a stereoscopic image or a reference image, which will be described later, without consciously perceiving the display device 1A.

[0016] As in Fig. 2, the light guide plate 20 comprises an exit surface 21, a rear surface 22 and an incidence surface 23.

[0017] The exit surface 21 is a surface that emits light guided inside the light guide plate 20 and whose light path is changed by a light path changing unit 30 described later. The exit surface 21 forms the front surface of the light guide plate 20. The rear surface 22 is a surface parallel to the exit surface 21 and is a surface on which the light path changing unit 30 is arranged. The rear surface 22 does not need to be parallel to the exit surface 21. The incident surface 23 is a surface at which the light emitted from the light source 10 enters the interior of the light guide plate 20.

[0018] The light emitted by the light source 10, which enters the light guide plate 20 from the incident surface 23, is totally reflected by the exit surface 21 or the rear surface 22 and guided through the light guide plate 20.

[0019] The light path changing unit 30 is arranged on the rear surface 22 inside the light guide plate 20 and is an element for changing the light path of the light guided in the light guide plate 20 to emit the light from the exit surface 21. Furthermore, the light path changing unit 30 is an element for generating a part of a stereoscopic image or a part of a reference image to be visually perceived by an observer. As shown in Fig. 3, a plurality of light path changing units 30 are provided on the rear surface 22 of the light guide plate 20.

[0020] Fig. 4(a) is a plan view showing the configuration of the light path changing unit 30, and Fig. 4(b) is a perspective view showing the configuration of the reflector 31a.

[0021] As in Fig. 4(a), the light path changing unit 30 consists of light path changing unit groups 31, 32, 33.... For the sake of simplicity, Fig. 4(a) only shows the light path changing unit groups 31 to 33. Each of the light path changing unit groups 31, 32, 33... is formed by a plurality of reflectors (prisms) arranged along a direction parallel to the incident surface 23. For example, the light path changing unit group 31 consists of a plurality of reflectors 31a. Similarly, the light path changing unit groups 32, 33... consist of a plurality of reflectors 32a and 33a, respectively.

[0022] As in Fig. As shown in Figure 4(b), the reflector 31a has a triangular pyramid shape and includes a reflection surface 31aa that reflects the incident light (total internal reflection). For example, the reflector 31a may be a recess formed on the back surface 22 of the light guide plate 20. The reflectors 32a, 33a, ... have the same structure as the reflector 31a. The reflector 31a is not limited to the triangular pyramid shape.

[0023] Fig. 5 is a perspective view showing the arrangement of the reflectors 31a, 32a, 33a in the light path changing unit 30.

[0024] As in Fig. 5, in the respective light path changing unit groups 31, 32, 33..., reflection surfaces 31aa, 32aa, 33aa... of the plurality of reflectors 31a, 32a, 33a... are arranged on the rear surface 22 of the light guide plate 20 so as to have different angles with respect to the incident direction of the light. Thus, each of the light path changing unit groups 31, 32, 33... changes the light path of the incident light and emits the light from the exit surface 21 in different directions.

[0025] Next, a method for generating a part of a stereoscopic image or a part of a reference image by the light path changing unit 30 will be described with reference to Fig. 6. Here, a plane image I, which is a part of a stereoscopic image, is formed on a stereoscopic image forming plane P, which is a plane vertical to the exit surface 21 of the light guide plate 20, by light whose light path is changed by the light path changing unit 30.

[0026] Fig. 6 is a perspective view illustrating a method for generating the plane image I by the light path changing unit 30. Here, the generation of a ring mark having diagonal lines as the plane image I on a stereoscopic image generation plane P will be described.

[0027] As in Fig. 6, in the display device 1A, the light whose light path is changed by each reflector 31a of the light path changing unit group 31 intersects the stereoscopic image formation plane P on a line La1 and a line La2. Thereby, a line image LI, which is part of the plane image I, is formed on the stereoscopic image formation plane P. The line image LI is a line image parallel to the YZ plane. In this way, the line image LI of the line La1 and the line La2 is formed by the light from each of a large number of reflectors 31a belonging to the light path changing unit group 31. Here, the light for forming the images of the lines La1 and La2 can be provided by at least two reflectors 31a in the light path changing unit group 31.

[0028] Similarly, the light whose light path is changed by each reflector 32a of the light path changing unit group 32 intersects the stereoscopic image formation plane P at the lines Lb1, Lb2, or Lb3. Thus, a line image LI, which is part of the plane image I, is formed on the stereoscopic image formation plane P.

[0029] Furthermore, the light whose light path is changed by each reflector 33a of the light path changing unit group 33 intersects the stereoscopic image formation plane P at the line Lc1 or Lc2. Thus, a line image LI, which is part of the plane image I, is formed on the stereoscopic image formation plane P.

[0030] The positions in the X-axis direction of the line images generated by the light path changing unit groups 31, 32, 33... differ from each other. In the display device 1A, by narrowing the distances between the light path changing unit groups 31, 32, 33..., it is possible to reduce the distance in the X-axis direction of the line image LI generated by the respective light path changing unit groups 31, 32, 33... Thereby, in the display device 1A, by accumulating a plurality of line images LI each formed by the light whose light path is changed by the respective reflectors 31a, 32a, 33a... of the light path changing unit groups 31, 32, 33..., the plane image I is substantially generated on the stereoscopic image generation plane P.

[0031] Here, the stereoscopic image formation plane P may be a plane vertical to the X-axis, a plane vertical to the Y-axis, or a plane vertical to the Z-axis. The stereoscopic image formation plane P may also be a plane that is not vertical to the X-axis, the Y-axis, or the Z-axis. Furthermore, the stereoscopic image formation plane P may be a curved surface instead of a plane. That is, the display device 1A can cause the light path changing unit 30 to form the plane image I on any plane (plane and curved surface) in the space. In the display device 1A, for example, a plane image is formed on a stereoscopic image formation plane vertical to the exit surface 21 by light whose light path is changed by one light path changing unit 30 of the plurality of light path changing units 30.A plane image is formed on a stereoscopic image forming plane parallel to the exit surface 21 by light whose light path is changed by another light path changing unit 30 of the plurality of light path changing units 30.

[0032] In Fig. In Fig. 3, each light path changing unit 30 is shown in a single area for convenience of description; however, the display device of the present invention is not limited thereto. That is, in the display device according to one aspect of the present invention, for example, two light path changing units 30 for displaying two stereoscopic images may be provided in the same area. (Examples of the display device 1A)

[0033] Next, display examples 1 to 6 of stereoscopic images using the display device 1A will be described. Fig. 7(a) to 7(d) and 8(a) to 8(d) are perspective views showing display examples of a stereoscopic image using the display device 1A. In the following description, the plurality of light path changing units 30 are referred to as light path changing units 30a, 30b, 30c to distinguish them from each other. <Darstellungsbeispiel 1>

[0034] Illustration example 1 is shown with reference to Fig. 7(a). As described in Fig. As shown in Fig. 7(a), in the present display example, the display device 1A forms a stereoscopic image I1, which is a plane image, on a stereoscopic image formation plane P1, which is a plane vertical to the exit surface 21 of the light guide plate 20. Specifically, the display device 1A forms the stereoscopic image I1 on the stereoscopic image formation plane P1 by the light whose light path is changed by the light path changing unit 30a.

[0035] As described above, in Display Example 1, the display device 1A forms the image of the stereoscopic image I1 on the stereoscopic image formation plane P1, which is a plane vertical to the exit surface 21. Thereby, even when the transparent light guide plate 20 is used, the display device 1A enables the viewer to visually perceive the stereoscopic image I1 with a stereoscopic effect.

[0036] In the present display example, an example was described in which the stereoscopic image I1 is generated (displayed) on the stereoscopic image generation plane P1, which is a plane vertical to the exit surface 21. However, the display device 1A of the present invention is not limited to this. That is, the display device 1A according to an embodiment of the present invention may generate (display) the stereoscopic image I1 on a plane that is not parallel to the exit surface 21. In this case, the stereoscopic image I1 is generated on a plane that intersects a plane parallel to the exit surface 21. Thereby, the display device 1A allows the viewer to visually perceive the stereoscopic image I1 with a stereoscopic effect even when the transparent light guide plate 20 is used.Here, the stereoscopic image I1 may be a part of a stereoscopic image generated by the display device 1A. That is, a stereoscopic image representing at least a part of the stereoscopic image may be generated (displayed) on the stereoscopic image generation plane P1. <Darstellungsbeispiel 2>

[0037] Illustration example 2 is shown with reference to Fig. 7(b). As described in Fig. 7(b), in the present display example, the display device 1A forms a stereoscopic image I2. The stereoscopic image I2 includes a plane image I2a formed on a stereoscopic image formation plane P2, which is a plane parallel to the exit surface 21 of the light guide plate 20, and a plane image I2b formed on a stereoscopic image formation plane P3, which is a plane parallel to the exit surface 21 and different from the stereoscopic image formation plane P2. Specifically, the display device 1A forms the plane image I2a on the stereoscopic image forming plane P2 by the light whose light path is changed by the light path changing unit 30b, and the plane image I2b on the stereoscopic image forming plane P3, which is a plane parallel to the exit surface 21, by the light whose light path is changed by the light path changing unit 30c.

[0038] As described above, in Display Example 2, the display device 1A forms the plane images I2a, I2b on the stereoscopic image formation planes P2, P3, which are respectively planes parallel to the exit surface 21 (i.e., the display device 1A forms the stereoscopic image I2). Thereby, the stereoscopic image I2 has two planes (plane images I2a, I2b) positioned on different planes from each other. Thereby, even when the transparent light guide plate 20 is used, the display device 1A can make the viewer feel that the plane images I2a, I2b are formed on different planes from each other. That is, the display device 1A enables the viewer to visually perceive the stereoscopic image I2 with the stereoscopic effect.

[0039] In the present display example, the stereoscopic image I2 consists of the two plane images I2a, I2b, but the display device 1A of the present invention is not limited thereto. Rather, the stereoscopic image I2 generated by the display device 1A may include plane images that are different from each other and generated on three or more mutually parallel stereoscopic image generation planes.

[0040] Furthermore, in the present display example, an example was described in which the plane images I2a, I2b are formed (displayed) on the stereoscopic image formation planes P2, P3, which are planes parallel to the exit surface 21. However, the display device 1A of the present invention is not limited to this. Rather, as shown in Fig. 7(c), the display device 1A according to the embodiment of the present invention generates (displays) plane images I3a, I3b as the stereoscopic image 13 on stereoscopic image generation planes P1, P4, which are planes vertical to the exit surface 21.

[0041] Furthermore, the display device 1A is not limited to the aspect in which the stereoscopic image is generated with two plane images on mutually parallel stereoscopic image generation planes. Rather, the display device 1A according to one aspect of the present invention can display stereoscopic images having two mutually different planes existing on planes that are not parallel to each other. The stereoscopic image generated by the display device 1A may include another surface or line in addition to the two planes. <Darstellungsbeispiel 3>

[0042] Illustration example 3 is shown with reference to Fig. 7(d). As described in Fig. As shown in Figure 7(d), in the present display example, the display device 1A generates a stereoscopic image I2A. The stereoscopic image I2A includes a line image I2c in addition to the plane images I2a, I2b in the stereoscopic image I2 of Display Example 2. The line image I2c is a line segment connecting the plane image I2a and the plane image I2b, which are generated on different planes from each other. The line segment I2c is formed by the light whose light path is changed by a light path changing unit 30d.

[0043] As described above, in Display Example 3, the display device 1A forms the stereoscopic image I2A with a line image I2c connecting the plane image I2a and the plane image I2b. This can convey to the viewer the sense of thickness of the stereoscopic image I2A with the line image I2c, allowing the viewer to visually perceive the stereoscopic image I2A with a stereoscopic effect. <Darstellungsbeispiel 4>

[0044] Example 4 is presented with reference to Fig. 8(a). As described in Fig. 8(a), in the present display example, the display device 1A forms a triangular prismatic stereoscopic image 14.

[0045] The stereoscopic image I4 comprises two line segments (e.g. the one in Fig. 8(a) shown line segments I4a, I4b) which are parallel to a plane and not parallel to each other, and a line segment which is not parallel to the plane (ie, which is shown in Fig. 8(a)). As a result, the stereoscopic image I4 is a stereoscopic image with a strong stereoscopic effect. Therefore, even when the transparent light guide plate 20 is used, the display device 1A allows the viewer to visually perceive the stereoscopic image I4 with a stereoscopic effect.

[0046] In Display Example 4, the display device 1A forms a triangular prismatic stereoscopic image 14, but the display device 1A of the present invention is not limited thereto. Rather, the stereoscopic image 14 formed by the display device 1A can be any stereoscopic image as long as it includes two line segments parallel to a plane and not parallel to each other, and one line segment not parallel to the plane. A stereoscopic image including three such components cannot be fitted to a plane, but always becomes a stereoscopic image with a three-dimensional shape. <Darstellungsbeispiel 5>

[0047] Illustration example 5 is shown with reference to Fig. 8(b). As described in Fig. 8(b), in the present display example, the display device 1A forms a reference image R1 separately from the stereoscopic image I1 in Display Example 1.

[0048] The reference image R1 comprises two line segments R1a, R1b that are parallel to the exit surface 21 and orthogonal to each other. The line segments R1a, R1b intersect at a point Q. The reference image R1 is formed by light whose light path is changed by the light path changing unit 30e.

[0049] As described above, in Display Example 5, the display device 1A generates the reference image R1 separately from the stereoscopic image I1. Since the viewer can perceive the stereoscopic image I1 with reference to the reference image R1 as a reference, the viewer can visually perceive the stereoscopic image I1 as an image with a stronger stereoscopic effect than in Display Example 1.

[0050] In the display example, the reference image R1 includes two line segments R1a, R1b parallel to the exit surface 21; however, the display device 1A of the present invention is not limited thereto. Rather, the reference image R1 generated by the display device 1A may be an image including two line segments orthogonal to each other and does not necessarily have to be parallel to the exit surface 21.

[0051] Furthermore, in the present display example, the example in which the reference image R1 comprising two line segments R1a, R1b is generated has been described; however, the display device 1A of the present invention is not limited to this. Rather, as shown in Fig. As shown in Figure 8(c), the display device 1A of one embodiment of the present invention generates a reference image R2 consisting of a plane image parallel to the exit surface 21. This allows the viewer to perceive the stereoscopic image I1 with reference to the reference image R2, so that the viewer can visually perceive the stereoscopic image I1 as an image with a stronger stereoscopic effect than in Display Example 1. The reference image R2 consists of the plane image and thus includes two line segments that are orthogonal to each other.

[0052] The plane on which the reference images R1, R2 are generated may be parallel to the plane on which the stereoscopic image I1 is generated, but is preferably not parallel thereto in order to enhance the stereoscopic effect of the stereoscopic image I1. The plane on which the reference images R1, R2 are generated is more preferably vertical to the plane on which the stereoscopic image I1 is displayed. Furthermore, the plane on which the reference images R1, R2 are generated is preferably parallel to the exit surface 21.

[0053] The display method in the present display example is particularly effective in a display device that displays stereoscopic images by parallax fusion using light emitted from a light guide plate as a transparent optical element. That is, in a parallax-type stereoscopic image display device, by allowing the viewer to perceive a reference image (by displaying it) including two line segments orthogonal to each other separately from an image perceived by the viewer as a stereoscopic image, the viewer can visually perceive a stereoscopic image with a stereoscopic effect. <Darstellungsbeispiel 6>

[0054] Illustration example 6 is shown with reference to Fig. 8(d). As described in Fig. As shown in Fig. 8(d), in the present display example, a display device 1A generates the reference image R1A separately from the stereoscopic image I1 in display example 1. The reference image R1A includes a line segment R1c in addition to the line segments R1a, R1b in the reference image R1 of display example 5. The line segment R1c is a line segment orthogonal to the line segments R1a, R1b.

[0055] As described above, in Display Example 6, the display device 1A generates a reference image R1A consisting of the three mutually orthogonal line segments R1a, R1b, R1c separately from the stereoscopic image I1. This allows the viewer to visually perceive the stereoscopic image I1 as an image with a stronger stereoscopic effect than in Display Example 5. Each of the line segments R1a, R1b, R1c may be displayed on a plane different from the plane on which the stereoscopic image I1 is generated. The line segment R1c may be parallel to the plane on which the stereoscopic image I1 is displayed.

[0056] When the stereoscopic image I1 is displayed using the light guide plate 20 as in the display device 1A of the present embodiment, due to shape irregularities (sagging or the like) of the reflectors 31a, 32a, 33a, the displayed stereoscopic image I1 may become unclear or its contrast may deteriorate, so that the stereoscopic effect of the stereoscopic image I1 may be impaired. On the other hand, in Display Example 6, by generating the reference image R1A consisting of three mutually orthogonal line segments R1a, R1b, R1c separately from the stereoscopic image I1, it is possible to increase the paths for obtaining a stereoscopic effect of the stereoscopic image I1. This makes it possible for the viewer to visually perceive a stereoscopic image with a stereoscopic effect.

[0057] The reference images R1, R1A, R2 in Display Examples 5 and 6 are images each generated by light whose light path is changed by the light path changing unit 30 of the display device 1A. However, the display device 1A of the present invention is not limited to this. Rather, in the display device 1A of one embodiment of the present invention, a line or plane image may be actually drawn as a reference image on the exit surface 21 or the back surface 22 of the light guide plate 20, for example, using a marker or the like. As a result, the drawn reference image can be displayed separately from the stereoscopic image.Furthermore, when a transparent sheet (thin film) in which a line or plane image is actually provided (pasted) as a reference image using a marker or the like on the exit surface 21 or the back surface 22 of the light guide plate 20, the drawn reference image can be displayed separately from the stereoscopic image.

[0058] In a conventional technology (e.g., three-dimensional (3D) television, etc.), a display device for displaying a stereoscopic image is provided with a frame (image frame) around an optical element that emits light perceived by a viewer as a stereoscopic image. This allows a viewer to perceive the stereoscopic image as an image having a stereoscopic effect, with the frame serving as a reference plane. However, when the display device is used as a guide plate or the like, it is preferable to omit the frame so that the viewer does not consciously perceive the display device.By displaying a stereoscopic image as described in the above display examples 1 to 6, in the display device 1A according to the present embodiment, a viewer can visually perceive a stereoscopic image with a stereoscopic effect even when there is no frame (image frame) (that is, when the light guide plate 20 is transparent). [Second embodiment]

[0059] In the following, another embodiment of the present invention will be described with reference to the Fig. 9 to 12. For the sake of simplicity, elements having the same function as those described in the above embodiment are designated by the same reference numerals and will not be described further.

[0060] A configuration of a display device 1B in the present embodiment will be described with reference to Fig. 9 described.

[0061] Fig. 9 is a perspective view illustrating the configuration of the display device 1B. As in Fig. 9, the display device 1B includes a two-dimensional image display device 40 in addition to the configuration of the display device 1A in the first embodiment, and a light guide plate 60 of the two-dimensional image display device 40, which will be described later, is arranged above the light guide plate 20.

[0062] Next, the device for displaying a two-dimensional image 40 is described with reference to the Fig. 10 to 12 described.

[0063] Fig. 10 is a perspective view illustrating a configuration of the two-dimensional image display device 40. Fig. 11 is a plan view showing a configuration of a light path changing unit 80 included in the two-dimensional image display device 40.

[0064] As in the Fig. 10 and Fig. 11, the two-dimensional image display device 40 includes a light source 50 and the light guide plate (optical element) 60.

[0065] The light source 50 is an element for irradiating the light guide plate 60 with light and is formed, for example, by a light-emitting diode (LED). The light source 50 may have a configuration including one light-emitting diode or a configuration including a plurality of light-emitting diodes.

[0066] The light guide plate 60 is a member that guides incident light from the light source 50. The shape of the light guide plate 60 is not limited; in the present embodiment, it has a substantially rectangular parallelepiped shape. The light guide plate 60 has substantially the same size as the light guide plate 20 in the display device 1A. The light guide plate 60 is made of a transparent resin material with a relatively high refractive index. For example, a polycarbonate resin, polymethyl methacrylate resin, or the like can be used as the material for forming the light guide plate 60. In the present embodiment, the light guide plate 60 is made of a polymethyl methacrylate resin.Since the light guide plate 20 and the light guide plate 60 are transparent in the display device 1B, the viewer can visually observe the rear surface side of the display device 1B through the light guide plate 20 and the light guide plate 60. Therefore, in the display device 1B, the viewer can observe a stereoscopic image or a reference image without consciously perceiving the display device 1B.

[0067] As in Fig. 10, the light guide plate 60 comprises an exit surface 61, a rear surface 62 and an incident surface 63.

[0068] The exit surface 61 is a surface that emits light guided inside the light guide plate 60 and whose light path is changed by a light path changing unit 80 described later. The exit surface 61 forms the front surface (front surface) of the light guide plate 60. The rear surface 62 is a surface parallel to the exit surface 61 and is a surface on which the light path changing unit 80 is arranged. The light path changing unit 80 will be described in detail later. The incident surface 63 is a surface at which the light emitted from the light source 50 enters the interior of the light guide plate 60.

[0069] The light path changing unit 80 is arranged on the rear surface 62 inside the light guide plate 60 and is a member for changing the light path of the light guided in the light guide plate 60 to emit the light from the exit surface 61. As shown in Fig. 11, the light path changing unit 80 consists of light path changing unit groups 81, 82, 83.... For the sake of simplicity, Fig. 11 only the light path changing unit groups 81 to 83 are shown.

[0070] Each of the light path changing unit groups 81, 82, 83 ... is located along a direction parallel to the incident surface 63 and is each formed by a part of a Fresnel lens.

[0071] In the display device 1B, for example, a point image is generated on the stereoscopic image generation plane by light whose light path is changed by the light path changing unit group 81. Similarly, a point image is generated on the stereoscopic image generation plane by the light whose light path is changed by the respective light path changing unit groups 82, 83... By reducing the distances between the light path changing unit groups 81, 82, 83... , it is possible in the display device 1B to reduce the spacing of the point images generated by the respective light path changing unit groups 81, 82, 83... Thus, in the display device 1B, by accumulating a plurality of point images, each formed by the light whose light path is changed by the respective light path changing unit groups 81, 82, 83...is changed, a stereoscopic image, which is a line image, is created essentially on the stereoscopic image creation plane.

[0072] Fig. 12 is a perspective view illustrating a display example by the display device 1B.

[0073] In the display device 1B, the light guide plate 60 is arranged above the light guide plate 20. As a result, as in Fig. 12, the stereoscopic image I1 is generated by the light emitted from the light guide plate 20, and the two-dimensional image D consisting of a plane image parallel to the exit surface 21 is generated by the light emitted from the light guide plate 60. Therefore, the viewer can perceive the two-dimensional image D as the stereoscopic image I1 as the reference image R2 in the above-described display example 5, so that the viewer can perceive the stereoscopic image I1 as an image with a stronger stereoscopic effect compared to the display example 1. [Third Embodiment]

[0074] In the following, another embodiment of the present invention will be described with reference to Fig. 13. For the sake of simplicity, elements having the same function as those described in the above embodiment are designated by the same reference numerals and will not be described further.

[0075] In the display devices 1A, 1B according to the first and second embodiments, the light path of the light guided within the light guide plate 20 or the light guide plate 60 is changed by the light path changing unit, and the light is emitted from the exit surface 21 or 61 to form a stereoscopic image or a reference image. However, the display method of the present invention is not limited to this. That is, light may also be emitted from the optical element by using light emitted from an object to display an original image, a stereoscopic image, or a reference image to form a stereoscopic image or a reference image.

[0076] A display device that emits light from an optical element using light emitted from an object for displaying an original image and generates a stereoscopic image or a reference image is, for example, (1) a display device using a two-sided reflector array structure in which a plurality of mutually orthogonal mirror surface elements are arranged in the plane of the optical coupling element, as disclosed in Patent Document 2; and (2) a so-called "Peppers Ghost" display device using a half mirror.Also in these display devices, the optical element such as the two-sided reflector array structure or the semi-transparent mirror (hereinafter referred to as optical element 100) is transparent, and the viewer can visually perceive the back surface side of the display device through the optical element 100.

[0077] The Fig. 13(a) and Fig. 13(b) are diagrams showing display examples of a display method using the optical element 100. Display examples 7 and 8 using the optical element 100 will be described with reference to Fig. 13 described. <Darstellungsbeispiel 7>

[0078] Illustration example 7 is shown with reference to Fig. 13(a). As described in Fig. 13(a), in the present embodiment, a display N1 and a display N2, which emit light for displaying an original image of a stereoscopic image I5, are arranged on one side with respect to the optical element 100. The display N1 and the display N2 are arranged in parallel with each other. The light emitted from the display N1 and the display N2 enters the optical element 100, changes its light path through the optical element 100, and is emitted from the optical element 100. Then, a plane image I5a and a plane image I5b are respectively formed as a stereoscopic image I5 on the side opposite to the side with respect to the optical element 100.

[0079] As described above, in Display Example 7, the plane images I5a, I5b are formed (i.e., the stereoscopic image I5 is formed). That is, the stereoscopic image I5 has two planes (the plane images I5a, I5b) that exist on different planes from each other. Therefore, even if the transparent optical member 100 is used in the present Display Example, it is possible to give the viewer the feeling that the two plane images I5a, I5b are formed on different planes. That is, in the present Display Example, the viewer can visually perceive the stereoscopic image I5 with a stereoscopic effect. <Darstellungsbeispiel 8>

[0080] Illustration example 8 is shown with reference to Fig. 13(b). As described in Fig. 13(b), in the present embodiment, a display N1 and a display N3, each emitting light to display an original image of a stereoscopic image I6, are arranged on one side with respect to the optical element 100. The display N3 includes a transparent light guide plate that emits light to display an original image. The display N1 and the display N1 are arranged vertically to each other. The light emitted from the display N1 and the display N3 enters the optical element 100, changes its light path through the optical element 100, and is emitted from the optical element 100. Then, by the light emitted from the optical element 100, a plane image I6a and a plane image I6b are respectively formed as a stereoscopic image I6 on the side opposite to the side with respect to the optical element 100. The display N3 includes a transparent light guide plate. Therefore, as shown in Fig.13(b), even if the display N3 is positioned closer to the optical element than the display N1, the light emitted from the display N1 can be passed through the display N3 to produce the plane image I6a.

[0081] As described above, in Display Example 8, the plane images I6a, I6b are generated (i.e., the stereoscopic image I6 is formed). That is, the stereoscopic image I6 has two mutually vertical surfaces (plane images I6a, I6b). Therefore, even when the transparent optical element 100 is used, in the present display example, it is possible to give the viewer the feeling that the two plane images I6a, I6b are formed on different planes. That is, in the present display example, the viewer can visually perceive the stereoscopic image I6 with a stereoscopic effect.

[0082] In Example 8, the display N3 includes the transparent light guide plate that emits light; however, the present invention is not limited to this. For example, instead of the display N3, an element equipped with a light-emitting body (e.g., a light-emitting diode arranged on a matrix or a light-emitting wire) on a transparent flat plate (e.g., a glass plate) may be used. Overview

[0083] A display method according to one aspect of the present invention is a method for displaying a stereoscopic image using a display device equipped with a transparent optical element, the display method comprising: emitting light to be perceived by a viewer as a stereoscopic image from the optical element; and displaying at least a part of the stereoscopic image on a plane that is not parallel to an exit surface of the optical element. In the display method, the viewer can visually perceive one side of the rear surface of the display device through the optical element.

[0084] With the above feature, since at least a part of the stereoscopic image is formed on a plane intersecting with a plane parallel to the exit surface, a viewer can visually perceive a stereoscopic image with a stereoscopic effect even if the optical element is transparent.

[0085] In the display method according to one aspect of the present invention, at least a part of the stereoscopic image can be displayed on a plane vertical to the exit surface of the optical element.

[0086] A display method according to one aspect of the present invention is a method for displaying a stereoscopic image using a display device equipped with a transparent optical element, the display method comprising emitting light to be perceived by a viewer as a stereoscopic image from the optical element. In the display method, the viewer can visually perceive one side of the rear surface of the display device through the optical element, and the stereoscopic image has two planes positioned on mutually different planes.

[0087] With the above feature, even when a transparent optical element is used, the viewer can feel that the stereoscopic image is created on two different surfaces. That is, the viewer can perceive a stereoscopic image with a stereoscopic effect.

[0088] In the display method according to one aspect of the present invention, the two planes may be parallel to each other.

[0089] In the display method according to one aspect of the present invention, the stereoscopic image preferably has a line connecting the two planes.

[0090] The line connecting the two planes can convey the viewer's sense of the thickness of the stereoscopic image. The viewer can thus visually perceive a stereoscopic image with a stereoscopic effect.

[0091] In the display method according to one aspect of the present invention, the two planes may be vertical to each other.

[0092] A display method according to one aspect of the present invention is a method for displaying a stereoscopic image using a display device equipped with a transparent optical element, the display method comprising emitting light to be perceived by a viewer as a stereoscopic image from the optical element. In the display method, the viewer can visually perceive one side of the rear surface of the display device through the optical element, and the stereoscopic image includes two line segments that are parallel to a plane and not parallel to each other, and one line segment that is not parallel to the plane.

[0093] With the above feature, it is possible to display a stereoscopic image with a strong stereoscopic effect. Thus, the viewer can perceive a stereoscopic image with a stereoscopic effect even when a transparent optical element is used.

[0094] In the display method according to one aspect of the present invention, the plane may be parallel to an exit surface of the optical element.

[0095] In the display method according to one aspect of the present invention, a reference image comprising two mutually orthogonal line segments is preferably displayed separately from the stereoscopic image.

[0096] Since the viewer can perceive the stereoscopic image with reference to the reference image as a reference, the viewer can visually perceive the stereoscopic image as an image with a stronger stereoscopic effect.

[0097] In the display method according to one aspect of the present invention, the two line segments contained in the reference image may be parallel to an exit surface of the optical element.

[0098] In the display method according to one aspect of the present invention, the two line segments contained in the reference image may intersect at a point.

[0099] In the display method according to one aspect of the present invention, the reference image may include a line segment that is orthogonal to the two line segments included in the reference image.

[0100] This allows the viewer to visually perceive the stereoscopic image as an image with a stronger stereoscopic effect.

[0101] In the display method according to one aspect of the present invention, the reference image may be formed by light emitted from the optical element.

[0102] In the display method according to one aspect of the present invention, another optical element may be provided so as to be arranged above the optical element, and the reference image may be generated by light emitted from the another optical element.

[0103] In the display method according to one aspect of the present invention, a transparent film on which an image is drawn as a reference image may be provided on the optical element.

[0104] In the display method according to one aspect of the present invention, the optical element can generate the stereoscopic image by guiding the incident light from the light source, changing the light path of the guided light, and emitting the light from the exit surface to generate the stereoscopic image.

[0105] A display device according to one aspect of the present invention displays a stereoscopic image by any of the above display methods.

[0106] The present invention is not limited to the respective embodiments described above, but may be subject to various modifications within the scope of the claims. Also included within the technical scope of the present invention is an embodiment obtained by appropriately combining the units disclosed in the respective different embodiments. DESCRIPTION OF REFERENCE NUMBERS 1A, 1B Display device 10, 50 light source 20, 60 Light guide plate (optical element) 21, 61 Exit surface 100 optical elements I1, I2, I2A, I3, I4, I5, I6 stereoscopic image R1, R1A, R2 reference image

Claims

A method for displaying a stereoscopic image using a display device (1A) equipped with a transparent optical element (20), the optical element (20) comprising: an incident surface (23), which is a surface at which the light emitted by a light source (10) enters the interior of the optical element (20); a rear surface (22) configured to totally reflect the light entering the optical element (20) from the incident surface (23); a light path changing unit (30) arranged on the rear surface (22) and configured to change a light path of the light guided through the optical element (20); an exit surface (21) configured to totally reflect the light entering the optical element (20) from the incident surface (23) and to emit the light whose light path is changed by the light path changing unit (30);and wherein the stereoscopic image is formed by the light whose light path is changed by the light path changing unit (30) and emitted from the exit surface (21). The display method comprises: emitting light that can be perceived by a viewer as a stereoscopic image from the optical element (20); and displaying at least a portion of the stereoscopic image on a plane parallel to the exit surface (21) of the optical element (20). The viewer can visually perceive one side of the rear surface (22) of the display device (1A) through the optical element (20). The stereoscopic image has two plane images (I2a, I2b) positioned on mutually different planes (P2, P3). The two plane images (I2a, I2b) are parallel to each other and coincide in shape and size. The two plane images (I2a, I2b) do not completely overlap.when viewed from a direction perpendicular to the two plane images (I2a, I2b). A display method according to claim 1, wherein the stereoscopic image has a line (L2c) connecting the two plane images (I2a, I2b).

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