Vehicle light

Abstract

An optical device capable of minimizing the deterioration of the visibility of a stereoscopic image comprises a light guide plate with a group of beam path deflection devices arranged to change the beam path of light from a first light source to produce an image in space within a first angular range, and to change the beam path of light from a second light source to produce an image in space within a second angular range, wherein the first angular range and the second angular range are separated from each other or adjacent to each other.

Description

TECHNICAL AREA

[0001] The present invention relates to a light guide plate which displays a stereoscopic image and to a vehicle lamp which uses the light guide plate. GENERAL STATE OF THE ART

[0002] The image display device disclosed in Japanese patent publication JP 2012 - 118 378 A (published on June 21, 2012) provides an example of a known optical device that displays a stereoscopic image.

[0003] Fig. Figures 18A to 18C illustrate configurations of an image display device 100 disclosed in the Japanese patent publication. As in Fig. Figure 18A shows that the image display device 100 disclosed in Japanese patent publication JP 2012-118378A (published on June 21, 2012) is equipped with a light guide plate 110 and a light source 101 provided at one end of the light guide plate 110. Display patterns 111a, 112a, 113a for a left eye with a plurality of first prisms and display patterns 111b, 112b, 113b for a right eye with a plurality of second prisms are formed on the back surface of the light guide plate 110. Display pattern 111a for the left eye uses a plurality of first prisms P1 to produce a symbol “A” in a two-dimensional plane, and display pattern 111b for the right eye uses a plurality of second prisms P2 to produce a symbol “A” in a two-dimensional plane. Fig. 18B).

[0004] In this configuration, the multitude of first and second prisms reflects light from the light source 101 to project an image for the left eye and an image for the right eye onto the front surface of the light guide plate 110. When a viewer looks at the image for the left eye and the image for the right eye, the viewer perceives each of the viewed images 120 of "A", "B", and "C" as a planar image that appears three-dimensional and is arranged in this order from furthest to nearest, as shown in Fig. Figure 18C illustrates this. The images 120 are perceived as floating at the intersection of the light rays from the images for the left eye and the images for the right eye. Therefore, the images with greater distances have intersection points that are closer to the viewer and thus appear closer. Consequently, the viewer is able to perceive a natural three-dimensional representation. Further prior art documents are US 2015 / 0131316 A1 and DE 112015005932T5. These each show a light guide plate for generating an image in space, where the light guide plate incorporates multiple light sources. Technical task

[0005] Fig. 19A is a perspective view illustrating a generated stereoscopic image projecting laterally from a wall along a corridor; Fig. Figure 19B is a top view illustrating the relationship between the stereoscopic image and a viewer looking at the stereoscopic image. Consider a stereoscopic image projecting laterally from a wall three meters (3 m) further along a corridor, as seen by a viewer one meter (1 m) away from a wall. Fig. 19A). In order for the viewer to recognize it as a stereoscopic image, the viewer must at least be able to see the image from a viewing angle of up to 75° relative to the normal of the wall ( Fig. 19B).

[0006] However, an existing image display device 100 has the disadvantage that the stereoscopic image it generates in the room is distorted and hardly appears three-dimensional when viewed from an angle greater than 60° relative to the normal of the wall. Such an angle is referred to in this specification as the wide viewing angle range.

[0007] The visibility of the stereoscopic image deteriorates over a wide viewing angle range for two reasons.

[0008] Fig. 20A and Fig. Section 20B explains the first reason why the visibility of the stereoscopic image deteriorates over a wide viewing angle. This primary reason is increased propagation sensitivity within that wide viewing angle range. Here, "propagation sensitivity" is defined as the ratio of the change in the emission angle of emitted light to the change in the optical path angle, taking into account the angle at which the light is directed. If the surface from which the light is emitted from the optical path is an emission surface, then the optical path angle is the angle formed by a ray of light traveling towards the emission surface with respect to the normal line of the emission surface on the inside of the optical path.The emission angle is the angle formed by the path of the emitted light from the emission surface in relation to the normal line of the emission surface on the outside of the light guide plate.

[0009] Consider that light in the optical fiber plate has an emission angle γ relative to the normal of the emission surface. At an emission angle of γ = 30°, the propagation sensitivity to the shape of the stereoscopic image is approximately 1 ( Fig. 20A and Fig. 20B). The propagation sensitivity to the shape of the stereoscopic image increases drastically at an emission angle of γ=60° or more and is approximately 19 at an emission angle of γ=75°. Consequently, the emission angle changes considerably over the wide viewing angle range if the optical fiber angle changes due to errors in the shape, which has a major impact on the blurring of the stereoscopic image.

[0010] Fig. Section 21 explains the first reason why the visibility of the stereoscopic image deteriorates over a wide viewing angle. The second reason concerns the area for perceiving any stereoscopic image. As in Fig. As shown in Figure 21, when generating a stereoscopic image, blurring is less likely to occur in the immediate vicinity, directly in front of the optical fiber plate, because only a narrow area is perceptible there. However, blurring is more noticeable over a wide viewing angle, since the emitted light is viewed from a wider area in that region.

[0011] The object underlying the invention can therefore be seen as providing an optical device capable of preventing the deterioration of the visibility of a stereoscopic image in a room within a wide viewing angle range. This object is achieved by the subject matter of independent claims 1 and 8. Preferred embodiments are the subject of the dependent claims. SUMMARY

[0012] To solve the preceding problems, a light guide plate according to an embodiment of the present invention is arranged to guide incident light onto it, to change the path of the guided light, and to emit the light from an emission surface of it, thereby producing an image in a room;wherein the light guide plate comprises: a group of beam path deflection devices that modify the beam path of the light, wherein the group of beam path deflection devices deflects the light incident on the light guide plate from a first light source, which is arranged at a predetermined position, to produce an image in space within a predetermined first angular range with respect to a reference plane which is orthogonal to the emission surface and parallel to a side face of the light guide plate, and deflects the light incident on the light guide plate from a second light source, which is arranged at a position remote from the position of the first light source, to produce an image in space within a predetermined second angular range with respect to the reference plane; wherein the first angular range and the second angular range may be separate from each other or adjacent to each other.

[0013] A light guide plate according to an embodiment of the present invention is configured to guide incident light onto it, to change the path of the guided light, and to emit the light from an emission surface thereof in order to generate an image in space, wherein the light guide plate has first beam path deflection devices and second beam path deflection devices, wherein the first beam path deflection devices change the path of the light incident on the light guide plate only from the first light source, which is arranged at a predetermined position, in order to generate a first image in space, wherein the second beam path deflection devices change the path of the light incident on the light guide plate only from a second light source, which is arranged at a position remote from the position of the first light source, in order to generate a second image in space.and wherein the first beam path deflection devices and the second beam path deflection devices overlap each other at least partially in a direction in which incident light is guided by the first light source and the second light source. Effects

[0014] According to one aspect of the present invention, an optical device can be provided which is able to prevent a deterioration of the visibility of a stereoscopic image in a room within a wide viewing angle range. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic view of an optical device to which the present invention applies; Fig. Figure 2 is a representation to describe a relationship between an image-forming angle and a light source for the light that produces a stereoscopic image in the optical device; Fig. Figure 3 is a perspective view of the configuration within the optical device for generating a planar image; Fig. Figure 4 is a top view of the configuration within the optical device for generating a planar image; Fig. Figure 5 is a front view illustrating an example of a stereoscopic image constructed from planar images produced by the optical device; Fig. Figure 6 is a schematic view of a vehicle light which includes the optical device; Fig. 7A and Fig. Figure 7B is a perspective view or a side view, illustrating a configuration of the optical device; Fig. 8A, Fig. 8B and Fig. Figure 8C are representations that illustrate a relationship between an image-forming angle and a light source for the light that produces a stereoscopic image: Fig. 8A shows a state in which the image generation angle is almost 0°, Fig. 8B shows a state in which the image generation angle is positive and small, and Fig. Figure 8C shows the state in which the image generation angle is positive and large; Fig. Figure 9 is a representation to describe a relationship between an image-forming angle and a light source in the optical device; Fig. Figure 10 is a top view showing parameters used to describe a superposition of angular ranges; Fig. Figure 11 is a top view showing parameters used to describe a superposition of angular ranges; Fig. 12A is a table which shows an example of the relationship between the distance x, the angle θ and the distance L when the light guide plate is made of polycarbonate, and Fig. 12B is a table which shows an example of the relationship between the distance x, the angle θ and the distance L when the light guide plate is made of acrylic; Fig. 13 is a graph which plots the value of the distance L with respect to the angle θ for each value of the distance x in the Fig. Example 12A shows; Fig. 14A is a graph showing the coefficient of the quadratic term of the angle θ in relation to the value of the distance x, Fig. Figure 14B is a graph showing the coefficient of the first-order term of the angle θ in terms of the value of the distance x, and Fig. 14C is a graph which shows a coefficient of a zeroth order term of the angle θ with respect to the value of the distance x; Fig. Figure 15 is a representation showing a relationship between an image generation angle and a light source in an optical device according to a first modified example of the present invention; Fig. Figure 16 is a representation showing a relationship between an image generation angle and a light source in an optical device according to a second modified example of the present invention; Fig. 17A and Fig. Figure 17B shows illustrations to describe a fourth modified example of the present invention; Fig. Figures 18A to 18C are illustrations that depict the configurations of an image display device disclosed in Japanese patent publication JP 2012 - 118 378 A (published on June 21, 2012); Fig. 19A is a perspective view illustrating a generated stereoscopic image projecting laterally from a wall along a corridor; Fig. Figure 19B is a top view illustrating the relationship between the stereoscopic image and a viewer looking at the stereoscopic image; Fig. 20A and Fig. 20B serves to describe the first reason why the visibility of a stereoscopic image deteriorates over a wide viewing angle range; Fig. 21 serves to describe the second reason why the visibility of a stereoscopic image deteriorates over a wide viewing angle range. DETAILED DESCRIPTION First embodiment

[0015] An embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") is described below with reference to the drawings. The present embodiment described below is in every respect merely an example of the present invention. It is understood that various improvements and modifications can be made without departing from the scope of the present invention. That is to say, when using the present invention, a specific configuration suitable for the embodiment can be provided if necessary. §1 Application Example

[0016] First, an example of a situation to which the present invention applies will be given with reference to Fig. 1 to 5 described.

[0017] Fig. Figure 1 shows a schematic view of an optical device 1A to which the present invention applies. As shown in Fig. As shown in Figure 1, the optical device 1A has a light source 2 and a light guide plate 10.

[0018] The light source 2 causes light to fall onto the light guide plate 10. In the Fig. In the example shown in Figure 1, the light source 2 comprises a first light source 2A and a second light source 2B. The first light source 2A and the second light source 2B are both light-emitting diodes (LEDs). However, the first light source 2A and the second light source 2B can also be light sources that are not LEDs. Furthermore, the light source 2 can comprise a light source that is neither the first light source 2A nor the second light source 2B. It should be noted that both the first light source 2A and the second light source 2B cause light to enter an incident surface 11, which will be described later. That is, the surface on which the light from the first light source 2A enters the light guide plate 10 and the surface on which the light from the second light source 2B enters the light guide plate 10 are the same side surface.

[0019] The light guide plate 10 directs the light incident on the incidence surface 11, alters the path of the guided light, and causes light to emerge from the emission surface to generate a stereoscopic image I in a room. The light guide plate 10 is made of a resin material that is transparent and has a relatively high refractive index. The light guide plate 10 can be made, for example, of a polycarbonate resin (PC), a polymethyl methacrylate resin (PMMA), or the like.

[0020] The light guide plate 10 has a group of beam path deflection devices 20 ( Fig. 3), which will be described later. Furthermore, the light guide plate 10 has an emission surface 12 ( Fig. 3) through which the light exits. The light is guided through the light guide plate 10, deflected by the group of beam path deflection devices 20 and caused to exit the emission surface 12 in order to produce the stereoscopic image I in a room.

[0021] Fig. Figure 2 is a diagram describing the relationship between an image-generating angle and the light source for the light that generates the stereoscopic image I in the optical device 1A. In the optical device 1A, the light source for the light that generates the stereoscopic image I varies depending on the image-generating angle. The image-generating angle is the angle of the position at which the stereoscopic image I is generated relative to a reference plane S of the optical fiber plate 10. The reference plane S is a plane orthogonal to the emission surface 12 and parallel to a side surface 14 ( Fig. 3) the light guide plate 10.

[0022] The light from the first light source 2A, for example, generates the stereoscopic image I in the image-generating angle within a first angular range AA, an angular range close to and directly in front of the light guide plate 10. In contrast, the light from the second light source 2B generates the stereoscopic image I in the image-generating angle within a second angular range AB, an angular range farther from and directly in front of the light guide plate 10 than angular range AA. In other words, the group of beam path deflection devices 20 modifies the beam path of the light incident on the light guide plate 10 from the first light source 2A, which is arranged at a predetermined position, in order to generate an image in the space within angular range AA with respect to the reference plane S.The group of beam path deflection devices 20 also changes the beam path of the light incident on the light guide plate 10 from the second light source 2B, which is located at a position away from the position of the first light source 2A, in order to produce an image in the space within the angular range AB with respect to the reference plane S.

[0023] In the Fig. In example 2, angular region AA and angular region AB are adjacent to each other. However, angular region AA and angular region AB can also be separated. If angular region AA and angular region AB have an overlapping area, the stereoscopic image I will appear doubled in that area at that time, which is not desirable.

[0024] The following describes the configuration of the light guide plate 10 for generating the image I in the room.

[0025] Fig. Figure 3 is a perspective view of the configuration within the optical device for generating a planar image FI. Fig. Figure 4 is a top view of the configuration within the optical device 1A for generating the planar image FI. Fig. Figure 5 is a front view illustrating an example of the stereoscopic image I, which is constructed from a planar image FI produced by the optical device 1A.

[0026] As in Fig. As shown in Figure 3, the light guide plate 10 has: an incidence surface 11, at which light from the light source 2 enters; an emission surface 12, which is the front surface of the light guide plate 10 and which emits light; and a rear surface 13, on which a group of beam deflection devices 20 is formed, which will be discussed below. The emission surface 12 and the rear surface 13 are parallel to each other, and the incidence surface 11 is perpendicular to both the emission surface 12 and the rear surface 13. Furthermore, the light guide plate 10 has a side surface 14, which is perpendicular to both the incidence surface 11, the emission surface 12, and the rear surface 13.

[0027] The group of beam deflection devices 20 is formed on the rear surface 13. The group of beam deflection devices 20 changes the beam path of the light guided through the light guide plate 10 and emits the light from the emission surface 12 to produce the stereoscopic image I in a room. For example, the group of beam deflection devices 20 can be prisms.

[0028] This means that, as described above, in Fig. 3. The light emitted by the light source 2 enters the light guide plate 10 through the incidence surface 11. The light incident on the light guide plate 10 is completely reflected between the emission surface 12 and the back surface 13 of the light guide plate 10 and directed to the far end of the light guide plate 10. Then, the group of beam path deflection devices 20 deflects the beam path of the light in a specific direction, thereby breaking the state of total internal reflection and the light being emitted from the emission surface 12.

[0029] Note that in the description of the first embodiment, a rectangular coordinate system with an x-axis, a y-axis, and a z-axis is sometimes used. In the first embodiment, the z-axis direction is defined as perpendicular to the emission surface 12, with the positive z-axis direction pointing from the rear surface 13 toward the emission surface 12. The y-axis direction is defined as perpendicular to the incidence surface 11, with the positive y-axis direction pointing from the incidence surface 11 toward the planar image FI facing the incidence surface 11. Furthermore, the x-axis runs along a direction orthogonal to the incidence surface 11 along a lateral surface of the optical fiber plate 10, with the positive x-axis direction pointing in Fig. 1 from the left side face to the right side face. To avoid repetition of the description, the plane parallel to the xy-plane can be called the xy-surface, the plane parallel to the yz-plane can be called the yz-surface, and the plane parallel to the xz-plane can be called the xz-surface. Regarding the angle of the optical fiber plate 10 with respect to the reference plane S, an angle on the negative x-direction side is a negative angle, and an angle on the positive x-direction side is a positive angle.

[0030] For example, assume that the optical device 1A produces a stereoscopic image I in a plane 30, in which a stereoscopic image is produced which is parallel to the xz-plane, as in Fig. 3 illustrates; and in particular, that the optical device 1A produces a planar image FI as a circle with a diagonal line.

[0031] A plurality of groups of first beam deflection devices 21a, 21b, 21c, ... is formed on the back surface 13 of the light guide plate 10 in the optical device 1A; wherein the groups of first beam deflection devices 21a, 21b, 21c, ... serve as the group of beam deflection devices 20. Each group of first beam deflection devices 21a, 21b, 21c, ... is formed from a plurality of prisms arranged along a direction parallel to the x-axis. For example, the group of first beam deflection devices 21a is composed of a plurality of prisms P21a. Similarly, the group of first beam deflection devices 21b is composed of a plurality of prisms P21b, and the group of first beam deflection devices 21c is composed of a plurality of prisms P21c.

[0032] For example, prisms P21a alter the path of incident light, spreading it in a direction parallel to the xy-plane and causing it to exit emission surface 12. The light rays emitted from emission surface 12 due to prisms P21a largely form a line that intersects plane 30, where the stereoscopic image is generated. As shown in Fig. 3 and Fig. As illustrated in Figure 4, the prisms P21a cause the light rays to emerge from the emission surface 12. The two emitted light rays intersect the plane 30, in which the stereoscopic image is produced, at a line 31a1 and a line 31a2. As shown in Figure 4, the prisms P21a cause the light rays to emerge from the emission surface 12. The two emitted light rays intersect the plane 30, in which the stereoscopic image is produced, at a line 31a1 and a line 31a2. Fig. As illustrated in Figure 3, each of the prisms P21a contained in the group of first beam-path deflection devices 21a, and other prisms P21a therein, cause light rays to emerge from the emission surface 12 in a similar manner and to intersect the plane 30, in which the stereoscopic image is produced, at line 31a1 and line 31a2. Line 31a1 and line 31a2 lie within a plane that is substantially parallel to the xy-plane and produce part of the stereoscopic image I. Thus, the light from the plurality of prisms P21a belonging to the group of first beam-path deflection devices 21a produces a line image LI, in particular line 31a1 and line 31a2.The light that produces the images of line 31a1 and line 31a2 can be provided by at least two prisms P21a and P21a in the group of first beam path deflection devices 21a, which are provided at different positions along the x-axis direction.

[0033] This means that each of the plurality of prisms P21a belonging to the group of first beam-path deflection devices 21a causes incident light to propagate along the x-axis direction within a plane parallel to the emission surface 12; wherein the plurality of prisms P21a causes light with an intensity distribution corresponding to the images of lines 31a1 and 31a2 to emerge from the emission surface 12. Thus, light from the plurality of prisms P21a belonging to the group of first beam-path deflection devices 21a and arranged along the x-axis direction is the light that produces the images of line 31a1 and line 31a2.

[0034] As in Fig. As illustrated in Figure 3, each of the prisms P21b in the group of first beam-path deflection devices 21b similarly alters the beam path of incident light, propagates the light in a direction parallel to the xy-plane, and causes three light rays to emerge from the emission surface 12. The three light rays emitted from the emission surface 12 intersect the plane 30, in which the stereoscopic image is produced, at lines 31a1, 31a2, and 31a3. Each of the prisms P21b contained in the group of first beam-path deflection devices 21a, and any other prisms P21b therein, similarly cause light rays to emerge from the emission surface 12 and intersect the plane 30, in which the stereoscopic image is produced, at lines 31b1, 31b2, and 31b3.In this way, each of the plurality of prisms P21b belonging to the group of first beam-path deflection devices 21b causes incident light to propagate along the x-axis direction within a plane parallel to the emission surface 12; wherein the plurality of prisms P21b causes light with an intensity distribution corresponding to the images of lines 31a1, 31a2, 31a3 to emerge from the emission surface 12. Thus, light from the plurality of prisms P21b belonging to the group of first beam-path deflection devices 21a and arranged along the x-axis direction is the light that produces the images of lines 31b1, 31b2, and 31b3. Lines 31b1, 31b2, and 31b3 lie within a plane that is substantially parallel to the xy-plane and produce part of the stereoscopic image I.

[0035] Here, lines 31b1, 31b2, 31b3 and lines 31a1, 31a2 are formed at different points along the z-axis direction in the plane 30 in which the stereoscopic image is generated.

[0036] As in Fig. As illustrated in Figure 3, the prisms P21c in the group of first beam-path deflection devices 21c similarly alter the beam path of incident light, spreading the light in a direction parallel to the xy-plane and causing two light rays to emerge from the emission surface 12. The two light rays emitted from the emission surface 12 intersect the plane 30, in which the stereoscopic image is produced, at lines 31c1 and 31c2. Each of the prisms P21c contained in the group of first beam-path deflection devices 21c, and any other prisms P21c therein, similarly cause light rays to emerge from the emission surface 12 and intersect the plane 30, in which the stereoscopic image is produced, at lines 31c1 and 31c2.Thus, each of the plurality of prisms P21c belonging to the group of first beam-path deflection devices 21c causes incident light to propagate within a plane parallel to the emission surface 12; each of the plurality of prisms P21c causes light with an intensity distribution corresponding to the images of lines 31a1, 31a2 to emerge from the emission surface 12. Light from the plurality of prisms P21c belonging to the group of first beam-path deflection devices 21c and arranged along the x-axis is the light that produces the images of lines 31c1 and 31c2. Lines 31c1, 31c2 lie within a plane that is substantially parallel to the xy-plane and produce part of the stereoscopic image I.

[0037] Here, lines 31c1, 31c2, lines 31b1, 31b2, 31b3 and lines 31a1, 31a2 are formed at different locations along the z-axis direction in the plane 30 in which the stereoscopic image is generated.

[0038] In Fig. Lines 31c1, 31c2, 31b1, 31b2, 31b3, and 31a1, 31a2 are formed at different locations along the z-axis direction in the plane 30 in which the stereoscopic image is generated, and each is perceived as isolated, as described above. However, the groups of first beam deflection devices 21a, 21b, 21c can actually be composed of several groups of first beam deflection devices 21a, 21b, 21c, ... with a smaller gap between the groups of first beam deflection devices 21a, 21b, 21c, ... in the y-axis direction.Alternatively, the beam path deflection angle for each of the prisms P21a, P21b, P21c can be selected such that, even if the groups of first beam path deflection devices 21a, 21b, 21c are separated along the y-axis direction, the lines 31a1, 21a2, the lines 31b1, 31b2, 31b3 and the lines 31c1, 31c2 are formed at positions that are closer to each other along the z-axis direction. Therefore, the planar image FI of a circle with a diagonal line can thus be perceived as the stereoscopic image I, as in . Fig. 5 illustrates.

[0039] Thus, the optical device 1A groups light rays from each of the plurality of prisms P21a, P21b, P21c into groups of first beam path deflection devices 21a, 21b, 21c, ..., which are arranged two-dimensionally. In this way, the optical device 1A uses the light rays to generate the planar image FI, which is projected in a space near a viewer. Therefore, a viewer is able to perceive a stereoscopic image I, which is generated from a planar image FI over a wide range of positions along the y-axis. §2 Configuration example

[0040] Next, a specific configuration of the present invention will be described with reference to Fig. 6 to 10 described.

[0041] Fig. Figure 6 is a schematic view of a vehicle light 100, which includes the optical device 1A. As in Fig. As illustrated in Figure 6, the vehicle light 100 has the optical device 1A. In a Fig. In the example shown in Figure 6, the optical device 1A comprises a first light source 2a to a fourth light source 2D and the light guide plate 10, and produces stereoscopic images I1 to I4. The vehicle light 100 further comprises a brake light 3 and a direction indicator light 4. The vehicle light 100 is a light that includes an indicator device, which is provided to the right and left of the rear of a vehicle.

[0042] Fig. 7A and Fig. Figures 7B are a perspective view and a side view, respectively, illustrating a configuration of the optical device 1A. The light guide plate 10 has the first beam deflection devices 21 to fourth beam deflection devices 24 as a group of beam deflection devices 20 on its rear surface 13. Each of the first beam deflection devices 21 to fourth beam deflection devices 24 modifies the beam path of light incident on the light guide plate 10 from one of the first light source 2A to fourth light source 2D in order to generate the stereoscopic images I1 to I4 in space ( Fig. 6) The first beam path deflection devices 21 to the fourth beam path deflection devices 24 can also be groups of beam path deflection devices comprising a plurality of prisms that modify the beam path of light. The areas in which the first beam path deflection devices 21 to the fourth beam path deflection devices 24 are formed partially overlap.

[0043] In the optical device 1A, the number of light sources contained in the light source 2 and the number of beam path deflection devices contained in the group of beam path deflection devices 20 can be three or fewer or greater than four. Furthermore, the number of light sources contained in the light source 2 and the number of beam path deflection devices contained in the group of beam path deflection devices 20 can differ from each other.

[0044] Furthermore, in the Fig. 7A and Fig. In the optical device 1A shown in Figure 7B, the first beam path deflection devices 21 are positioned outside the region through which the light emitted by the fourth light source 2D is directed. Similarly, the fourth beam path deflection devices 24 are positioned outside the region through which the light emitted by the first light source 2A is directed. This means that at least part of the group of beam path deflection devices 20 is positioned outside the region through which the light emitted by the first light source 2A or the fourth light source 2D is directed.

[0045] Furthermore, in optical device 1A, the stereoscopic images I1 to I4 are images of the same or similar designs, repeated at a distance from each other in the direction from the first light source to the second light source. Therefore, even if the light sources projecting the image are switched, it is unlikely that a user will notice the switch. This improves the visibility of the image.

[0046] Fig. 8A, Fig. 8B and Fig. Figures 8C are representations illustrating a relationship between an image-generating angle and a light source for the light that produces each of the stereoscopic images I1 to I4: Fig. 8A shows a state in which the image generation angle is almost 0°, Fig. 8B shows a state in which the image generation angle is positive and small, and Fig. Figure 8C shows a state in which the image-forming angle is positive and large. When the image-forming angle is increased from 0°, the optical device 1A changes its state from the one shown in Figure 8C. Fig. The state shown in 8A is related to the one described in Fig. 8B and Fig. 8C states shown in this order.

[0047] When the image generation angle is nearly 0°, the stereoscopic image I1 is generated from the light emitted by the first light source 2A, as shown in Fig. 8A is shown. Similarly, the stereoscopic images I2 to I4 are generated from light emitted by the second light source 2B to the fourth light source 2D. Furthermore, if the image-generating angle is positive and small, the stereoscopic images I1 to I4 are generated from the light emitted by the first light source 2A to the fourth light source 2D ( Fig. 8B), as in the case where the image generation angle is almost 0°.

[0048] In contrast, if the image-forming angle is positive and large, stereoscopic image I1 is generated from the light emitted by the second light source 2B, stereoscopic image I2 is generated from the light emitted by the third light source 2C, and stereoscopic image I3 is generated from the light emitted by the fourth light source 2D. In this case, the light emitted by the first light source 2A does not generate a stereoscopic image. Furthermore, stereoscopic image I4 is not generated.

[0049] If the image-forming angle is negative and has a large absolute value, the stereoscopic images I2 to I4 are generated from the light emitted by the first light source 2A to the third light source 2C, in reverse order of the sequence described in the original text. Fig. 8C shows the example. In this case, the light emitted by the fourth light source 2D does not produce a stereoscopic image and the stereoscopic image I1 is not generated.

[0050] It is preferred that the stereoscopic images I1 to I4, produced by the group of beam path deflection devices 20, are repetitions of the same or similar designs, repeating in the direction from the first light source 2A to the fourth light source 2D. If the stereoscopic images I1 to I4 are repetitions of the same or similar designs, users are less likely to detect any switching of light sources when the light sources producing the stereoscopic image are switched. Users will see the stereoscopic image without noticing any inconsistency.

[0051] Fig. Figure 9 is a representation to describe a relationship between an image-forming angle and a light source in the optical device 1A. In particular, Fig. 9 a representation showing a range of image-generating angles in which each light source projects the stereoscopic image I2 produced by the second beam path deflection devices 22 of the optical device 1A.

[0052] The light source used to generate the stereoscopic image I2 via the second beam path deflection devices 22 is different for each of the following image-generating angles: (i) within a second angular range A2 close to 0°; (ii) within a first angular range A1 with angles smaller than the second angular range A2; (iii) within a third angular range A3 with angles larger than the second angular range A2; and (iv) within a fourth angular range A4 with angles larger than the third angular range A3. In particular, when the image-generating angle is within the second angular range A2, the light from the second light source 2B generates the stereoscopic image I2. Likewise, when the image-generating angle is within the first angular range A1, the light from the first light source 2A generates the stereoscopic image I2.Furthermore, if the image-forming angle lies within the third angular range A3, the light from the third light source 2C produces the stereoscopic image I2. Furthermore, if the image-forming angle lies within the fourth angular range A4, the light from the fourth light source 2D produces the stereoscopic image I2.

[0053] In other words, the second beam path deflection devices 22 modify the beam path of light incident on the light guide plate 10 from the first light source 2A to produce an image in the space within the first angular range A1. The second beam path deflection devices 22 also modify the beam path of light incident on the light guide plate 10 from the second light source 2A to produce an image in the space within the second angular range A2. Furthermore, the second beam path deflection devices 22 modify the beam path of light incident on the light guide plate 10 from the third light source 2C to produce an image in the space within the third angular range A3. Finally, the second beam path deflection devices 22 modify the beam path of light incident on the light guide plate 10 from the fourth light source 2D to produce an image in the space within the fourth angular range A4.

[0054] In this case, when the image-forming angle is changed from -90° to +90°, the light sources for generating the stereoscopic image I2 change three (3) times: when the image-forming angle shifts (i) from the first angular region A1 to the second angular region A2; (ii) from the second angular region A2 to the third angular region A3; and (iii) from the third angular region A3 to the fourth angular region A4. The second angular region A2 can, for example, be a region greater than or equal to -14° and less than or equal to +14°. The first angular region A1 can, for example, be a region greater than or equal to -50° and less than -14°, and the third angular region A3 can, for example, be a region greater than +14° and less than or equal to +50°. The fourth angular region A4 can, for example, be a region greater than +50° and less than or equal to +80°.The first angle range A1, the second angle range A2, the third angle range A3, and the fourth angle range A4 are not limited to the preceding examples. The first angle range A1, the second angle range A2, the third angle range A3, and the fourth angle range A4 are either separate from each other or adjacent to each other. Conditions under which the first angle range A1 and the second angle range A2 do not overlap

[0055] Fig. Figure 10 is a top view showing parameters used to describe a superposition of angular ranges. Fig. Figure 11 is a top view showing parameters used to describe the superposition of angular ranges.

[0056] In Fig. In equation 10, θ1 is the lower limit of the image-forming angle for the light from the first light source 2A. Simultaneously, θ2 is the upper limit of the image-forming angle for the light from the second light source 2B. Fig. In section 10, it is assumed that the light from the first light source 2A is deflected symmetrically with respect to the reference plane S. This means that the path of the light from the first light source 2A is modified such that it lies within the angular range greater than or equal to -θ1 and less than or equal to θ1. As long as |θ1| ≤ |θ2|, the first angular range A1 and the second angular range A2 do not overlap.

[0057] As in Fig. As shown in Figure 11, 'L' represents a distance within the light source 2, that is, a distance between the first light source 2A and the second light source 2B and a distance between the second light source 2B and the third light source 2C; and 'x' represents the distance from the light source 2 to the group of beam deflection devices 20. The inclined surface of the first beam deflection devices 21, which reflects the light, has an angle of inclination α with respect to the x-axis direction.

[0058] Using the in Fig. 10 and Fig. The parameters shown in Figure 11 are described below as conditions under which the first angular range A1 and the second angular range A2 do not overlap. The optical fiber plate 10 has a refractive index n.

[0059] Fig. Table 12A shows an example of the relationship between the distance x, the angle θ and the distance L when the light guide plate 10 is made of polycarbonate (refractive index n = 1.585). Fig. Figure 12B is a table showing an example of the relationship between distance x, angle θ, and spacing L when the optical fiber plate 10 is made of acrylic (refractive index n = 1.49). In the Fig. 12A and Fig. In the examples shown in 12B, the angles φ of the inclined surface of the group of beam path deflection devices 20 with respect to the bottom surface of the light guide plate 10 are every 50°.

[0060] In Fig. 12A and Fig. In step 12B, the position of the first beam path deflection devices 21 relative to the first light source 2A is first determined such that the distance x assumes a desired value (84°, 50°, or 30°). Next, the tilt angle α is selected so that the angle θ1 assumes a desired value (10°, 20°, 30°, or 40°). Then, the distance L between the first light source 2A and the second light source 2B is determined such that the angle θ2 is equal to the angle θ1.

[0061] Fig. 13 is a graph which plots the value of the distance L with respect to the angle θ for each value of the distance x in the Fig. The example shown in 12A illustrates this. As in Fig. As shown in Figure 13, the value of the distance L with respect to the angle θ is approximated by a quadratic equation for each value of the distance x as follows: x=84:L=0.0115θ2+1.6395θ+1.4331 x=50:L=0.00054θ2+1.0079θ+0.6616 x=30:L=0.0032θ2+0.6016θ+0.3894 Based on these approximation equations, it is assumed that the coefficients of the second-order term, the first-order term, and the zeroth-order term of the angle θ are all proportional to the value of the distance x.

[0062] Fig. 14A is a graph showing the coefficient of the quadratic term of the angle θ in relation to the value of the distance x. Fig. Figure 14B is a graph showing the coefficient of the first-order term of the angle θ in relation to the value of the distance x. Fig. 14C is a graph showing a coefficient of a zeroth-order term of the angle θ with respect to the value of the distance x. As in Fig. 14A, Fig. 14B and Fig. As shown in Figure 14C, the coefficients of the second-order term, the first-order term, and the zero-order term of the angle θ with respect to the distance x are approximated as follows: Second-order term of angle θ: k2 = 0.0002x - 0.0019 First-order term of angle 0: k1 = 0.0192x + 0.036 Zeroth order term of angle 0: k0 = 0.0197x - 0.2481

[0063] For better understanding, the coefficients of the second-order term, the first-order term and the zeroth-order term of the angle θ in the preceding equations are expressed as k2, k1 and k0 respectively.

[0064] Therefore, the condition of the distance L under which the first angle range A1 and the second angle range A2 do not overlap is expressed as follows: L>(0.0002x−0.0019)θ2+(0.0192x−0.036)θ+(0.0197x−0.2481).

[0065] If the distance L satisfies the preceding expression, the distance between the first angle range A1 and the second angle range A2 can be excessively large. Therefore, for example, the condition for the distance L can be expressed as follows: L>(0.0002x−0.0019)θ2+(0.0192x−0.036)θ+(0.0197x−0.2481)−10. The value "-10" in the preceding formula was determined based on experimental data. Furthermore, the two previously described types of distance L conditions are examples and can be modified accordingly. Conditions in which the light sources change twice

[0066] So that the light sources that create the image change twice when the image generation angle is changed from -90° to +90° ( Fig. 9), the distance L, the distance x and the refractive index n must satisfy: 90−arctan(x / 2L)≤W and 90−arctan(x / L)≤W

[0067] In the preceding formula, 90 - arctan(x / 2L) represents the angle in the direction from the third light source 2C to the first beam deflection devices 21. 90 - arctan(x / L) represents the angle in the direction from the second light source 2B to the first beam deflection devices 21. W represents the angle of propagation of light from the third light source 2C and the second light source 2B. That is, the preceding two formulas each indicate that the first beam deflection devices 21 lie within the region of the light propagating from the third light source 2C, and that the first beam deflection devices 21 lie within the region of the light propagating from the second light source 2B. W could, for example, be arcsin(1 / n).

[0068] If the preceding formulas are satisfied, the light from any one of the first light sources 2A to the third light source 2C produces an image depending on the image-forming angle. This means that if the image-forming angle is changed from -90° to +90°, the light sources producing the image change twice.

[0069] Fig. Figure 11 illustrates the first light source 2A and the second light source 2B and third light source 2C arranged to the left of the first light source 2A. In this case, the stereoscopic image I is mainly generated in the positive angular range. However, the present embodiment can include another light source arranged to the right of the first light source 2A. This can extend the negative angular range in which the stereoscopic image I is generated.

[0070] Furthermore, in the Fig. In example 11, the first angle range A1 is the reference plane S ( Fig. 10) and the second angular region A2 and the third angular region A3 can be on the same side with respect to the first angular region A1. In this case, when the image-forming angle is changed from directly in front of the light guide plate 10 to the direction of the second angular region A2 and the third angular region A3, the light sources that produce a stereoscopic image change twice, while the image-forming angle changes by 90°. If the light sources change frequently in this way, it is possible to further prevent a deterioration in the visibility of the stereoscopic image.

[0071] Furthermore, in the Fig. In the example shown in Figure 11, the first beam deflection devices 21 among the beam deflection devices contained in the group of beam deflection devices 20 could be, for example, the beam deflection devices that are furthest away from the incident surface 11. In other words, the distance x can be the distance between the incident surface 11 and the beam deflection device furthest from it that is contained in the group of beam deflection devices 20.

[0072] If the angle between the first light source 2A and the second light source 2B, as viewed from the perspective of the beam path deflection devices, is considered an intermediate light source angle, then in this case the first beam path deflection devices 21 exhibit the smallest intermediate light source angle among the beam path deflection devices 20. Therefore, the first beam path deflection devices 21 exhibit the strictest conditions for the distance L in the preceding formulas for generating an image in a first angular region A1 and a second angular region A2 that do not overlap. If the first beam path deflection devices 21 satisfy these conditions, then all beam path deflection devices 20 can consequently generate an image in a first angular region A1 and a second angular region A2 that do not overlap.

[0073] Furthermore, in the Fig. In the example shown, the first beam deflection devices 21 are those positioned at a midpoint between the beam deflection devices closest to and furthest from the incident surface 11 among the beam deflection devices contained in the group of beam deflection devices 20. In other words, the distance x can be the distance between the incident surface 11 and the midpoint.

[0074] If the optical fiber 10 is configured to produce images both in front of and behind the optical fiber when viewed from the side of the emission surface 12 of the optical fiber 10, the beam deflection devices furthest from the incidence surface 11 are those that produce an image from the perspective of the emission surface 12 behind the optical fiber 10. Conversely, the beam deflection devices closest to the incidence surface 11 are those that produce an image from the perspective of the emission surface 12 in front of the optical fiber 10.Therefore, if the beam path deflection devices located at the center of these beam path deflection devices satisfy the conditions for L described above, the images produced from the perspective of the emission surface 12 behind and in front of the light guide plate can be produced in both the first angular range A1 and the second angular range A2.

[0075] Beam path deflection devices do not necessarily have to be present at the center point of the group of beam path deflection devices. Even if no beam path deflection devices are present at the center point, images can be generated both behind and in front of the light guide plate when viewed from the side of the emission surface 12, in the first angular range A1 and the second angular range A2, as long as the distance L satisfies the preceding formulas with respect to the distance x to the center point. Effect

[0076] As described above, according to the optical device 1A of the present embodiment, the light sources for the light that generates the stereoscopic image change depending on the image-generating angle. Therefore, the stereoscopic image can be perceived from a wide angular range, encompassing the first angular range A1, the second angular range A2, and the third angular range A3. Consequently, it is possible to prevent blurring in an image generated over a range of image-generating angles with large absolute values.

[0077] In particular, when the optical device 1A is used in a vehicle light, such as the vehicle light 100, it is legally required that an image produced by the optical device 1A be perceptible when the image generation angle is 80°. The optical device 1A is capable of fulfilling the aforementioned legal requirement.

[0078] Furthermore, in the optical device 1A of the present embodiment, the three light sources can generate images in a space within angular ranges that are separated from each other or adjacent to each other. Therefore, generated images can be perceived from a wide angular range. §3 Modified Examples First Modified Example

[0079] Fig. Figure 15 is a diagram illustrating the relationship between an image-forming angle and a light source in an optical device 1B according to a first modified example of the present invention. The values ​​of the previously described distance L and the distance x for the optical device 1B differ from those for the optical device 1A. In the optical device 1B, light from different light sources produces a stereoscopic image I in a second angular range A6, where the image-forming angle has small absolute values, and in a first angular range A5 with angles smaller than the angles in the second angular range A6. Conversely, no stereoscopic image I is produced if the image-forming angle is larger than the second angular range A6.In this case, when the image-forming angle is changed from -90° to +90°, the light sources used to generate the stereoscopic image I change only once, when the image-forming angle shifts from the first angular range A5 to the second angular range A6. The first angular range A5 can, for example, be a range greater than or equal to -80° and less than or equal to -30°. The second angular range A6 can, for example, be a range greater than -30° and less than or equal to +10°.

[0080] So that the light sources used to create the image change once when the image generation angle is changed from -90° to +90° ( Fig. 15), the distance L, the distance x and the refractive index n must satisfy: 90−arctan(x / 2L)>W and 90−arctan(x / L)≤W

[0081] These formulas each indicate that the first beam path deflection devices 21 are not within the area of ​​light propagation from the third light source 2C and that the first beam path deflection devices 21 are within the area of ​​light propagation from the second light source 2B.

[0082] If the preceding formulas are satisfied, the light from either the first light source 2A or the second light source 2B produces an image depending on the image-forming angle. This means that if the image-forming angle is changed from -90° to +90°, the light sources used to create an image change once. Therefore, the generated image can be perceived over a wide angular range, encompassing the first angular range A5 and the second angular range A6. Second modified example

[0083] Fig. Figure 16 is a diagram showing a relationship between an image-forming angle and a light source in an optical device 1C according to a second modified example of the present invention. The values ​​of the previously described distance L and the distance x for the optical device 1C differ from the values ​​for the optical devices 1A and 1B. With the optical device 1C, the stereoscopic image I is generated only in the first angular range A7, in which the absolute value of the image-forming angle is small. Here in the optical device 1C, the first beam path deflection devices 21 ( Fig. 7A and Fig. 7B) the stereoscopic image I1 (first image) in space by changing the beam path only of the light incident on the optical fiber plate 10 from the first light source 2A. The second beam path deflection devices 22 ( Fig. 7A and Fig. 7B) also generate the stereoscopic image I2 (second image) in the room by modifying the beam path only of the light incident on the optical fiber plate 10 from the second light source 2B. In other words, neither the first beam path deflection devices nor the second beam path deflection devices deflect light from both the first and second light sources. No stereoscopic image I is generated in the room in the regions of the image-generating angle outside the first angular range A7. The first angular range A7 can, for example, be a range greater than or equal to -35° and less than or equal to +35°.

[0084] To ensure that the light sources generating the stereoscopic image I do not change when the image-generating angle is changed from -90° to +90°, the distance L and the distance x, which are specified in Fig. 11 are shown, and the refractive index n is fulfilled: 90−arctan(x / 2L)≤W and 90−arctan(x / L)>W

[0085] These formulas each indicate that the first beam path deflection devices 21 are not within the area of ​​light propagation from the third light source 2C and that the first beam path deflection devices 21 are not within the area of ​​light propagation from the second light source 2B.

[0086] If the preceding formulas are satisfied, the light from the first light source 2A and the second light source 2B each produce the stereoscopic image I. This means that if the image-forming angle is changed from -90° to +90°, the light sources producing the respective stereoscopic image I do not change. According to the optical device 1C, therefore, images do not overlap, even if the first and second light sources are switched on simultaneously. This prevents a deterioration of visibility due to a double stereoscopic image I produced by the light from the first light source 2A and the light from the second light source 2B. This means that even if a multiple of light sources are provided on the same side of the light guide plate to extend the image-forming area, each produced image can be displayed clearly.Furthermore, stereoscopic images I1 and I2 are repetitions of the same or similar configurations, repeated in the direction from the first light source 2A to the second light source 2B. This minimizes the deterioration in visibility due to a double stereoscopic image I, generated by the light from the first light source 2A and the light from the second light source 2B. This improves the visibility of stereoscopic image I. However, stereoscopic images I1 and I2 do not necessarily have to be repetitions of the same or similar configurations.

[0087] Furthermore, the first beam path deflection devices 21 and the second beam path deflection devices 22 overlap at least partially in the direction in which incident light from the first light source 2A and the second light source 2B is directed. In other words, it is not necessary to arrange the first beam path deflection devices 21 and the second beam path deflection devices 22 so that they do not overlap in the direction of the directed light. This increases the degree of freedom when the first beam path deflection devices 21 and the second beam path deflection devices 22 are arranged. Third modified example

[0088] In a light guide plate according to an embodiment of the present invention, a group of beam path deflection devices can display 20 patterns for a right eye and a left eye similar to those in Fig. The 18 shown display patterns 111b, 112b, 113b for the right eye and display patterns 111a, 112a, 113a for the left eye. The display patterns for the right eye produce an image for the right eye, and the display patterns for the left eye produce an image for the left eye. In this configuration, the stereoscopic images I1 to I4, which are produced by the first beam path deflection devices 21 to the fourth beam path deflection devices 24, can have a stereoscopic effect. Fourth modified example

[0089] Fig. 17A and Fig. Figure 17B shows illustrations describing a fourth modified example of the present invention. Note that in Fig. 17A and Fig. For the sake of simplicity, only one light source 2 is shown in 17B.

[0090] In the Fig. In the example shown in 17A, the light emitted by the light source 2 enters the light guide plate 10 through a slot 10a. This configuration reduces the propagation of light in the light guide plate 10. Furthermore, in the Fig. In the example shown in Figure 17B), the light emitted by the light source 2 is directed into the light guide plate 10 through a depression 10b formed on a surface of the light guide plate 10. This configuration increases the propagation of light in the light guide plate 10.

[0091] As described above, the light guide plate 10, according to the present modified example, can modify the propagation of incident light from the light source 2 by having the slot 10a or the recess 10b. A similar effect is also obtained if a lens or the like is provided between the light source 2 and the light guide plate 10.

[0092] In particular, it is possible to increase the number of light sources providing the light entering the respective beam deflection devices by increasing the propagation of the incident light from light source 2. This, in turn, makes it possible to change the light source multiple times to generate an image according to the varying image-forming angle, further improving the visibility of the image.

[0093] The present invention is not limited to the embodiments described above; various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are likewise included within the technical scope of the present invention. overview

[0094] As described above, a light guide plate according to an embodiment of the present invention is configured to guide incident light onto it, to change the path of the guided light, and to emit the light from an emission surface of it, thereby producing an image in a room;wherein the light guide plate comprises: a group of beam path deflection devices that modify the beam path of the light, wherein the group of beam path deflection devices deflects the light incident on the light guide plate from a first light source, which is arranged at a predetermined position, to produce an image in space within a predetermined first angular range with respect to a reference plane which is orthogonal to the emission surface and parallel to a side face of the light guide plate, and deflects the light incident on the light guide plate from a second light source, which is arranged at a position remote from the position of the first light source, to produce an image in space within a predetermined second angular range with respect to the reference plane; wherein the first angular range and the second angular range are separated from each other or adjacent to each other.

[0095] According to the configuration described above, the light guide plate causes incident light from the first and second light sources to be emitted from its emission surface. Light from the first light source incident on the light guide plate creates an image in a space within a predetermined first angular range with respect to a reference plane that is orthogonal to the emission surface and parallel to a side face of the light guide plate. Furthermore, light from the second light source incident on the light guide plate creates an image in a space within a predetermined second angular range with respect to the reference plane. The first and second angular ranges are either separated or adjacent to each other. Therefore, the user can perceive the image created in both the first and second angular ranges.It is therefore possible to minimize the deterioration of the visibility of a stereoscopic image in a room within a wide viewing angle range.

[0096] The optical fiber board according to one embodiment of the present invention fulfills 90−arctan(x / 2L)>W and 90−arctan(x / L)≤W where L is a distance between the first light source and the second light source, x is a distance between the incident surface and the beam path deflection devices, n is a refractive index of the light guide plate, and W is a propagation angle of the light from the first light source and the second light source.

[0097] According to the preceding configuration, the light sources that project the image generated in the room change when the image generation angle of the image is changed from -90° to +90° with respect to the reference plane.

[0098] Furthermore, in the light guide plate according to an embodiment of the present invention, x is the distance between the incident surface and a beam deflection device furthest away from it in the group of beam deflection devices.

[0099] A beam deflection device located furthest from the incident surface must meet stricter requirements than any other beam deflection device in order to produce an image in the first angular range and the second angular range. Therefore, according to the preceding configuration, all beam deflection devices included in the group can produce an image in a first angular range and a second angular range that do not overlap.

[0100] Furthermore, in the light guide plate according to an embodiment of the present invention, x is the distance between the incident surface and a midpoint within the group of beam path deflection devices, and the midpoint is between a beam path deflection device which is closest to the incident surface and a beam path deflection device which is furthest away from the incident surface in the group of beam path deflection devices.

[0101] If the optical fiber is configured to produce images both in front of and behind the optical fiber when viewed from the emission surface, the beam deflection devices furthest from the incidence surface are those that produce an image beyond the optical fiber when viewed from the emission surface. Conversely, the beam deflection devices closest to the incidence surface are those that produce an image further in front of the optical fiber when viewed from the emission surface. Therefore, according to the preceding configuration, both the image produced behind the optical fiber and the image produced in front of the optical fiber can be produced in the first and second angular ranges when viewed from the emission surface.

[0102] Furthermore, according to an embodiment of the present invention, the light guide plate is configured to change the beam path of the light incident on the light guide plate from a third light source, which is arranged at a position remote from the positions of the first and second light sources, in order to generate an image in a space within a predetermined third angular range with respect to the reference plane, wherein the first angular range, the second angular range and the third angular range are separated from each other or adjacent to each other.

[0103] According to the preceding configuration, the light incident on the optical fiber plate from the third light source creates an image in the space within the third angular area, which is separated from or adjacent to the first and second angular areas. Therefore, a user can perceive the image generated in all three angular areas. It is thus possible to further minimize the deterioration of the stereoscopic image's visibility within a space across a wide viewing angle range.

[0104] Furthermore, in the light guide plate according to an embodiment of the present invention, the first angular region has the reference plane and the second angular region and the third angular region are on the same side with respect to the first angular region.

[0105] According to the previously mentioned configuration, when the image-generating angle is changed from directly in front of the light guide plate to the direction of the second and third angle ranges, the light sources that generate a stereoscopic image change twice, while the image-generating angle changes by 90°. If the light sources change frequently in this way, it is possible to further minimize the deterioration of the stereoscopic image's visibility.

[0106] The optical fiber board according to one embodiment of the present invention fulfills: 90−arctan(x / 2L)≤W and 90−arctan(x / L)≤W where L is a distance between the first light source and the second light source and between the second light source and the third light source, x is the distance between the incident surface and the beam deflection devices, n is the refractive index of the light guide plate, and W is a propagation angle of the light from the first light source and the second light source.

[0107] According to the preceding configuration, the light sources that project the image generated in the room change twice when the image generation angle of the image is changed from -90° to +90° with respect to the reference plane.

[0108] Furthermore, a light guide plate according to an embodiment of the present invention is configured to guide incident light onto it, to change the path of the guided light, and to emit the light from an emission surface thereof in order to generate an image in a space, wherein the light guide plate has first beam path deflection devices and second beam path deflection devices for changing the beam path of the light, and wherein the first beam path deflection devices change the beam path only of the light incident on the light guide plate from the first light source, which is arranged at a predetermined position, in order to generate a first image in a space, and wherein the second beam path deflection devices change the beam path only of the light incident on the light guide plate from a second light source, which is arranged at a position remote from the position of the first light source.to produce a second image in a room, wherein the first beam path deflection devices and the second beam path deflection devices overlap each other at least partially in a direction in which the incident light is guided by the first light source and the second light source.

[0109] According to the preceding configuration, the first beam deflection devices only change the beam path of the light from the first light source to produce a first image in the room. Furthermore, the second beam deflection devices only change the beam path of the light from the second light source to produce a second image in the room. In other words, neither the first nor the second beam deflection devices deflect light from both the first and second light sources. Therefore, even if, for example, the first and second light sources are switched on simultaneously, the images do not overlap, thus improving the visibility of both the first and second images.This means that even if multiple light sources are provided on the same surface of the optical fiber to extend the image-generating area, each generated image can be clearly displayed. Furthermore, the first and second beam deflection devices overlap at least partially in the direction in which incident light is directed by the first and second light sources, respectively. This increases the degree of freedom in the arrangement of the first and second beam deflection devices.

[0110] The optical fiber board according to one embodiment of the present invention fulfills: 90−arctan(x / 2L)>W and 90−arctan(x / L)>W where L is a distance between the first light source and the second light source, x is a distance between the incident surface through which the light enters the light guide plate and the first beam deflection devices and the second beam deflection devices, n is the refractive index of the light guide plate, and W is a propagation angle of the light from the first light source and the second light source.

[0111] According to the preceding configuration, the light sources that project the image generated in the room do not change when the image generation angle of the image is changed from -90° to +90° with respect to the reference plane.

[0112] Furthermore, in the light guide plate according to an embodiment of the present invention, the group of beam path deflection devices has display patterns for a right eye and display patterns for a left eye, wherein the display patterns for the right eye generate an image for the right eye and the display patterns for the left eye generate an image for the left eye.

[0113] The configuration described above can produce a stereoscopic image.

[0114] Furthermore, in a light guide plate according to an embodiment of the present invention, the images are images of the same or similar designs that are repeated at a distance from each other in the direction from the first light source to the second light source.

[0115] Based on the configuration described above, it is unlikely that users will notice any switching of light sources used to project the image. This improves the image's visibility.

[0116] A vehicle light according to an embodiment of the present invention has a light guide plate according to one of the embodiments described above. Aspects of the invention:

[0117] According to a first aspect of the invention, a light guide plate, which is configured to guide incident light, to change the path of the guided light, and to emit the light from an emission surface thereof, thereby producing an image in a room, comprises: a group of beam path deflection devices that change the beam path of the light, wherein the group of beam path deflection devices deflects the light incident on the optical fiber plate from a first light source, which is arranged at a predetermined position, in order to produce an image in space within a predetermined first angular range with respect to a reference plane which is orthogonal to the emission surface and parallel to a side face of the optical fiber plate; and deflects the light incident on the optical fiber plate from a second light source, which is located at a position remote from the position of the first light source, in order to produce an image in space within a predetermined second angular range with respect to the reference plane; wherein the first angular range and the second angular range are separate from each other or adjacent to each other.

[0118] According to a second aspect of the invention, the light guide plate fulfills the requirements of the first aspect: 90−arctan(x / 2L)>W and 90−arctan(x / L)≤W where L is a distance between the first light source and the second light source, x is the distance between an incident surface through which the light enters the light guide plate and the group of beam path deflection devices, n is the refractive index of the light guide plate, and W is the propagation angle of the light from the first light source and the second light source.

[0119] According to a third aspect of the invention, the light guide plate according to the second aspect requires that x is the distance between the incident surface and a beam deflection device furthest away from it in the group of beam deflection devices.

[0120] According to a fourth aspect of the invention, the light guide plate according to the second aspect requires that x is the distance between the incident surface and a center point in the group of beam path deflection devices, and the midpoint between a beam deflection device that is closest to the incident surface and a beam deflection device that is furthest away from the incident surface in the group of beam deflection devices.

[0121] According to a fifth aspect of the invention, the light guide plate according to the first aspect requires that the group of beam path deflection devices modifies the beam path of the light incident on the light guide plate from a third light source, which is arranged at a position remote from the positions of the first and second light sources, in order to produce an image in a space within a predetermined third angular range with respect to the reference plane; and the first angle range, the second angle range and the third angle range are separated from each other or adjacent to each other.

[0122] According to a sixth aspect of the invention, the light guide plate according to the fifth aspect requires that the first angular range includes the reference plane and The second angle range and the third angle range lie on the same side with respect to the first angle range.

[0123] According to a third aspect of the invention, the light guide plate fulfills the requirements of the fifth or sixth aspect: 90−arctan(x / 2L)≤W and 90−arctan(x / L)≤W where L is a distance between the first light source and the second light source and between the second light source and the third light source, x is the distance between the incident surface where the light enters and the group of beam deflection devices, n is the refractive index of the light guide plate, and W is the propagation angle of the light from the first light source and the second light source.

[0124] According to an eighth aspect of the invention, a light guide plate, which is configured to guide incident light, to change the path of the guided light, and to emit the light from an emission surface thereon in order to produce an image in a room, comprises: first beam path deflection devices and second beam path deflection devices as a group of beam path deflection devices which change the beam path of the light, wherein The first beam path deflection devices change the beam path only of the light incident on the light guide plate from a first light source, which is arranged at a predetermined position, in order to produce a first image in a room; The second beam path deflection devices modify the beam path of only the light incident on the light guide plate from a second light source, which is arranged at a position remote from the position of the first light source, in order to produce a second image in a room; and The first beam path deflection devices and the second beam path deflection devices overlap each other at least partially in a direction in which incident light is guided by the first light source and the second light source.

[0125] According to a ninth aspect of the invention, the light guide plate fulfills the requirements of the eighth aspect: 90−arctan(x / 2L)≤W and 90−arctan(x / L)>W where L is a distance between the first light source and the second light source, x is a distance between an incident surface through which the light enters the light guide plate and the first and second beam path deflection devices, n is the refractive index of the light guide plate, and W is the propagation angle of the light from the first light source and the second light source.

[0126] According to a tenth aspect of the invention, the light guide plate according to one of the first to the ninth aspects requires that the group of beam path deflection devices has display patterns for a right eye and display patterns for a left eye, and that the display patterns for the right eye produce an image for the right eye and the display patterns for the left eye produce an image for the left eye.

[0127] According to an eleventh aspect of the invention, the light guide plate according to one of the first to the eighth aspects requires that the image is a repetition of the same or mutually similar configurations, which are repeated at a distance from each other in a direction from the first light source to the second light source.

[0128] According to a twelfth aspect of the invention, a vehicle lamp comprises the light guide plate according to one of the aspects from the first to the eleventh.

Claims

[1] Vehicle lamp (100) comprising a light guide plate (10) which is configured to guide incident light, to change the path of guided light and to emit the light from an emission surface thereon and thereby to produce an image in a room, wherein the light guide plate (10) comprises: a group of beam path deflection devices (20) that change the beam path of the light, wherein the group of beam path deflection devices (20) deflects the light incident on the light guide plate (10) from a first light source (2A) which is arranged at a predetermined position in order to produce an image in the space within a predetermined first angular range (A1) with respect to a reference plane (S) which is orthogonal to the emission surface and parallel to a side surface of the light guide plate (10); and the light incident on the light guide plate (10) from a second light source (2B), which is located at a position away from the position of the first light source (2A), is deflected in order to produce an image in the space within a predetermined second angular range (A2) with respect to the reference plane (S); where the first angle range (A1) and the second angle range (A2) are either separate from each other or adjacent to each other. [2] Vehicle light (100) according to claim 1, comprising the light guide plate (10): 90°−arctan(x / 2L)>W and 90°−arctan(x / L)≤W where L is a distance between the first light source (2A) and the second light source (2B), x is the distance between an incident surface through which the light enters the light guide plate (10) and the group of beam path deflection devices (20), n is the refractive index of the light guide plate (10) and W is the propagation angle of the light from the first light source (2A) and the second light source (2B). [3] Vehicle light (100) according to claim 2, wherein x is the distance between the incident surface and a beam deflection device furthest from it in the group of beam deflection devices (20). [4] Vehicle lamp (100) according to claim 2, wherein x is the distance between the incident surface and a midpoint in the group of beam deflection devices (20), and wherein the midpoint is between a beam deflection device which is closest to the incident surface and a beam deflection device which is furthest away from the incident surface in the group of beam deflection devices (20). [5] Vehicle lamp (100) according to claim 1, wherein the group of beam path deflection devices (20) modifies the beam path of the light incident on the light guide plate (10) from a third light source (2C), which is arranged at a position remote from the positions of the first and second light sources (2A, 2C), in order to produce an image in a space within a predetermined third angular range (A3) with respect to the reference plane (S); and wherein the first angular range (A1), the second angular range (A2) and the third angular range (A3) are separated from each other or adjacent to each other. [6] Vehicle light (100) according to claim 5, wherein the first angular region (A1) comprises the reference plane (S) and the second angular region (A2) and the third angular region (A3) are on the same side with respect to the first angular region (A1). [7] Vehicle light (100) according to claim 5 or 6, comprising the light guide plate (100): 90°−arctan(x / 2L)>W and 90°−arctan(x / L)≤W where L is a distance between the first light source (2A) and the second light source (2B) and between the second light source (2B) and the third light source (2C), x is the distance between the incident surface where the light enters and the group of beam deflection devices (20), n is the refractive index of the light guide plate (10) and W is the propagation angle of the light from the first light source (2A) and the second light source (2B). [8] Vehicle lamp (100) comprising a light guide plate (10) configured to guide incident light thereon, to change the path of the guided light and to emit the light from an emission surface thereon to produce an image in space, wherein the light guide plate (10) comprises: first beam path deflection devices (21) and second beam path deflection devices (22) as a group of beam path deflection devices (20) which change the path of the light, wherein the first beam path deflection devices (21) modify the beam path only of the light incident on the light guide plate (10) from a first light source (2A) which is arranged at a predetermined position in order to produce a first image in a room; the second beam path deflection devices (22) modify the beam path only of the light incident on the light guide plate (10) from a second light source (2B), which is arranged at a position remote from the position of the first light source (2B), in order to produce a second image in a room; and the first beam path deflection devices (21) and the second beam path deflection devices (22) overlap each other at least partially in a direction in which incident light is directed from the first light source (2A) and the second light source (2A). [9] Vehicle light (100) according to claim 8, comprising the light guide plate (10): 90°−arctan(x / 2L)>W and 90°−arctan(x / L)>W where L is a distance between the first light source (2A) and the second light source (2B), x is a distance between an incident surface through which the light enters the light guide plate (10) and the first and second beam path deflection devices (21, 22), n is the refractive index of the light guide plate (10) and W is the propagation angle of the light from the first light source (2A) and the second light source (2B). [10] Vehicle light (100) according to one of claims 1 to 9, wherein the group of beam path deflection devices (20) has display patterns for a right eye and display patterns for a left eye and the display patterns for the right eye produce an image for the right eye and the display patterns for the left eye produce an image for the left eye. [11] Vehicle light (100) according to any one of claims 1 to 8, wherein the image is a repetition of the same or of mutually similar configurations, which are repeated at a distance from each other in a direction from the first light source (2A) to the second light source (2B).

Images