Light guide plate

Abstract

To provide a light guide plate or a display device capable of suppressing the degradation of the quality of displayed images.SOLUTION: A light guide plate 10 includes: a light guide 10A; a light guide 10B; a deflection element 30A that causes light to incident into the light guide 10A by selectively deflecting the light of the first wavelength component contained in the incident light; and a deflection element 30B that causes light to incident into the light guide 10B by selectively deflecting the light of the second wavelength component contained in the incident light.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a light guide plate and a display device. [Background technology]

[0002] An optical device capable of widening the angle of view of a displayed image has been disclosed (see Patent Document 1). The optical device has a plurality of hologram elements in a light guide plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-112746 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the quality of an image displayed using a light guide plate may be degraded.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a light guide plate or the like that suppresses deterioration in the quality of a displayed image. [Means for solving the problem]

[0006] A light guide plate according to one embodiment of the present invention is a light guide plate including a first light guide, a second light guide, a first deflection element that selectively deflects light of a first wavelength component contained in incident light so that it is incident on the first light guide, and a second deflection element that selectively deflects light of a second wavelength component contained in the incident light so that it is incident on the second light guide. Effect of the Invention

[0007] The light guide plate according to the present invention can suppress deterioration in the quality of a displayed image. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing an example of a vehicle in which a display device according to an embodiment is installed. [Diagram 2] FIG. 2 is a schematic diagram showing the configuration of the display device. [Diagram 3] FIG. 3 is a schematic diagram showing the configuration of a light guide plate according to the related art. [Figure 4] FIG. 4 is a schematic diagram showing the configuration of a light guide plate according to the embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing a first example of the configuration of the incident portion according to the embodiment. [Figure 6] FIG. 6 is a schematic diagram showing a second example of the configuration of the incident portion according to the embodiment. [Figure 7] FIG. 7 is a schematic diagram showing a first example of the configuration of a light guide plate according to a modified example of the embodiment. [Figure 8] FIG. 8 is a schematic diagram showing a second example of the configuration of a light guide plate according to a modified example of the embodiment. [Figure 9] FIG. 9 is a schematic diagram showing a third example of the configuration of a light guide plate according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Findings on which the present invention is based) There is a display device that projects an image onto a transparent plate such as a windshield (generally called a front glass) of a vehicle, and allows a user such as a driver to view the image together with the scenery on the other side of the transparent plate. Such a display device is generally also called a head-up display device.

[0010] Fig. 1 is a schematic diagram showing a vehicle 5 which is an example of a vehicle in which a display device 1 is installed. Fig. 2 is a schematic diagram showing the configuration of the display device 1.

[0011] As shown in Fig. 1, a vehicle 5 includes a display device 1 and a windshield 20. The display device 1 is installed, for example, under the windshield 20, and emits light (also referred to as display light) related to image display upward, i.e., toward the windshield 20. The display device 1 is installed, for example, inside the dashboard. An optical path for the display light emitted by the display device 1 is secured, in other words, the emitted display light reaches the windshield 20 without being blocked. The configuration of the display device 1 will be described in more detail.

[0012] As shown in FIG. 2, the display device 1 includes a light guide plate 10 and an image generating device 17.

[0013] The image generating device 17 is a device that generates display light and provides it to the light guide plate 10. The image generating device 17 generates the display light, for example, by irradiating light emitted from a light source (not shown) included in the image generating device 17 onto an image forming element such as a liquid crystal. The image generating device 17 emits the generated display light toward the light guide plate 10.

[0014] The light guide plate 10 is a plate that deflects the display light generated by the image generating device 17 while expanding the beam width of the light. Here, the beam width means the width of the light flux in a direction perpendicular to the light traveling direction.

[0015] Display light generated by the image generating device 17 is incident on the light guide plate 10. The incident display light is guided within the light guide plate 10 and emitted to the outside of the light guide plate 10 as light L3. The light L3 is reflected by the windshield 20 to become light L5, which enters the eye of the user U. The light guide plate 10 is installed in a position and attitude such that the light L3 is emitted toward the windshield 20.

[0016] The expansion and deflection of the beam width of the display light by the light guide plate 10 is achieved by using a plurality of diffractive elements included in the light guide plate 10. Therefore, each of the plurality of diffractive elements included in the light guide plate 10 has a diffractive characteristic for diffracting the display light in an appropriate direction, and also has an appropriate dimension.

[0017] When the light L5, which is the display light, is incident on the user U's eyes, the user U views the image generated by the image generating device 17. The user U recognizes the image viewed by the light L5, which is the display light, as a virtual image 14 located on the other side of the windshield 20.

[0018] The above-mentioned functions of the light guide plate 10 can also be realized by an optical member such as a concave mirror. However, using the light guide plate 10 has an advantage that the dimensions of the display device 1 can be made smaller than when using an optical member such as a concave mirror. Since the display device 1 is installed inside the dashboard of the vehicle 5, for example, making the dimensions smaller has the advantage of allowing greater freedom in installation.

[0019] However, there may be a decrease in the quality of an image displayed using the light guide plate 10. Specifically, when the light guide plate 10 uses multiple light guides to guide light of multiple wavelengths, the quality of an image displayed by the display device 1 may decrease due to a decrease in light intensity or the occurrence of stray light.

[0020] The degradation of the quality of the displayed image due to the reduction in the light intensity or the occurrence of stray light will be described in detail below. A light guide plate that causes such degradation of the quality of the displayed image will be referred to as a light guide plate 90.

[0021] Fig. 3 is a schematic diagram showing the configuration of a light guide plate 90 according to the related art. Fig. 3(a) is a diagram showing the configuration when the light guide plate 90 is viewed from above, that is, when viewed from the positive direction of the Z axis. Fig. 3(b) is a diagram showing the configuration when the light guide plate 90 is viewed from the side, that is, when viewed from the negative direction of the Y axis. Fig. 3(c) is a diagram showing the configuration when the light guide plate 90 is viewed from the side, that is, when viewed from the positive direction of the X axis.

[0022] 3(b) and (c), the light guide plate 90 includes light guides 90A, 90B, and 90C (also referred to as light guides 90A, etc.). The light guides 90A, etc. are arranged in a parallel orientation to each other and are arranged at overlapping positions when viewed from above. The light guides 90A, etc. have the same shape, for example, a rectangular shape, when viewed from above, but are not limited thereto.

[0023] Fig. 3(a) shows only the light guide 90A among the light guides 90A etc. The same explanation as for Fig. 3(a) also applies to the light guides 90B and 90C.

[0024] 3, light guide 90A is a plate having transparent member 15 and hologram elements 91A, 12A, and 13A (also referred to as hologram element 91A, etc.) inside or on the surface of transparent member 15. Light guide 90A guides incident light L1 by total reflection inside light guide 90A, and emits light deflected by diffraction by hologram element 91A, etc. to the outside of light guide 90A as light L3A. Transparent member 15 is made of glass, acrylic resin, or the like.

[0025] Light L1 incident on light guide 90A is light traveling in the positive Y-axis direction and the positive Z-axis direction. It is assumed that light L1 is display light generated by image generating device 17, and in this case, contains light of multiple wavelength components (e.g., light of red, green, and blue wavelength components). Light guide 90A is installed in a position and attitude such that light L1 is incident at an appropriate angle as shown in FIG. 3 when display device 1 is in use (i.e., when display device 1 is installed as shown in FIG. 2).

[0026] The hologram element 91A is a diffraction element disposed inside or on the surface of the light guide 90A. The hologram element 91A deflects the light L1 incident from the outside to the inside of the light guide 90A by diffraction, and propagates the light inside the light guide 90A. The hologram element 91A has linear interference fringes formed when viewed from above, and deflects the light L1 by diffraction due to the interference fringes to produce light L12A and LA. The light L12A is light traveling in the negative direction of the X axis and is light of a specific frequency component (for example, light of a frequency component corresponding to red). The light L12A propagates inside the light guide 90A in the negative direction of the X axis by repeating total reflection at the interface between the transparent member 15 and the air.

[0027] The interference fringes formed on the hologram element 91A are interference fringes that deflect the light L1 so that the light L12A is totally reflected at the interface between the transparent member 15 and the air. Specifically, the interference fringes deflect the light L1 so that the incident angle of the light L12A on the interface is kept larger than the critical angle.

[0028] Moreover, the light LA ​​is light traveling in the negative direction of the X-axis and is light of a frequency component other than the specific frequency component (for example, light of a frequency component corresponding to blue and green). The light LA ​​is light generated due to the variation in the diffraction angle for each frequency when the light L1 is diffracted by the hologram element 91A. When the light LA ​​is diffracted by the interference fringes, it may or may not be totally reflected at the interface between the transparent member 15 and the air, and becomes stray light.

[0029] The hologram element 12A is a diffraction element disposed inside or on the surface of the light guide 90A. The hologram element 12A deflects the light L12A deflected by the hologram element 91A by diffraction, and propagates the light inside the light guide 90A. The hologram element 12A has linear interference fringes formed when viewed from above, and deflects the light L12A by diffraction due to the interference fringes to become light L23A. The light L23A travels in the positive direction of the Y axis. The light L23A propagates inside the light guide 90A in the positive direction of the Y axis by repeating total reflection at the interface between the transparent member 15 and the air.

[0030] The interference fringes formed on the hologram element 12A are interference fringes that deflect the light L12A so that the light L23A is totally reflected at the interface between the transparent member 15 and the air. Specifically, the interference fringes deflect the light L12A so that the incident angle of the light L23A on the interface is kept larger than the critical angle.

[0031] Hologram element 13A is a diffraction element disposed inside or on the surface of light guide 90A. Hologram element 13A deflects light L23A deflected by hologram element 12A by diffraction, and emits it to the outside of light guide 90A. Linear interference fringes are formed in hologram element 13A when viewed from above, and light L23A is deflected by diffraction due to the interference fringes to become light L3A. Light L3A travels in the Y-axis positive direction and the Z-axis positive direction.

[0032] The interference fringes formed on the hologram element 13A are interference fringes that deflect the light L23A so that the light L3A is emitted from the light guide 90A without being totally reflected at the interface between the transparent member 15 and the air. Specifically, the interference fringes deflect the light L23A so that the incident angle of the light L3A on the interface is kept smaller than the critical angle.

[0033] The light guide 90A is disposed at a position and in a posture such that the emitted light L3A travels toward the windshield 20 when the display device 1 is in use.

[0034] The light guide 90B is similar to the light guide 90A. Light L1B transmitted through the hologram element 91A is incident on the light guide 90B. The light guide 90B deflects the incident light L1B, and diffracts the light of a specific frequency component (for example, light of a frequency component corresponding to green) sequentially by the hologram elements 91B, 12B, and 13B to emit light L3B. At that time, the light guide 90B generates light LB, which becomes stray light.

[0035] The light guide 90C is similar to the light guide 90A. Light L1C that has passed through the hologram element 91B is incident on the light guide 90C. The light guide 90C deflects the incident light L1C, and diffracts the light of a specific frequency component (for example, light of a frequency component corresponding to blue) sequentially by the hologram elements 91C, 12C, and 13C to emit light L3C. At that time, the light guide 90C generates light LC that becomes stray light.

[0036] The light beams L3A, L3B, and L3C become light beam L3 and are emitted from the light guide plate 90. After being emitted from the light guide plate 90, the light beam L3 is reflected by the windshield 20 and enters the eye of the user U.

[0037] Here, since light L1B is diffracted by hologram element 91A, the intensity of light L1B is lower than the intensity of light L1. Also, since light L1C is diffracted by hologram elements 91A and 91B, the intensity of light L1 is lower than the intensity of light L1. Therefore, the intensity of light L3 is lower than the intensity of light L1. Furthermore, when light L1 is diffracted by hologram elements 91A and 91B, lights LA, LB, and LC, which are stray light, are generated.

[0038] In this way, when the light guide plate 90 diffracts the incident light L1, the intensity of the light decreases, or stray light occurs, degrading the quality of the displayed image.

[0039] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a light guide plate or the like that suppresses deterioration in the quality of a displayed image.

[0040] A light guide plate according to one embodiment of the present invention is a light guide plate including a first light guide, a second light guide, a first deflection element that selectively deflects light of a first wavelength component contained in incident light so that it is incident on the first light guide, and a second deflection element that selectively deflects light of a second wavelength component contained in the incident light so that it is incident on the second light guide.

[0041] According to the above aspect, the light guide plate selectively deflects the two wavelength components of the incident light by the deflection element, so that the light is incident on each of the two light guides, thereby suppressing the decrease in light intensity and the occurrence of stray light. In this way, the light guide plate can suppress the decrease in the quality of the displayed image.

[0042] In addition, the first deflection element may selectively reflect light of the first wavelength component contained in the incident light, thereby allowing it to be incident on the first light guide, and transmit light other than the first wavelength component contained in the incident light, and the second deflection element may selectively reflect light of the second wavelength component contained in the incident light, thereby allowing it to be incident on the second light guide, and transmit light other than the second wavelength component contained in the incident light.

[0043] According to the above aspect, the light guide plate allows the two wavelength components of the incident light to be incident on the two light guides by using the reflection by the deflection element, so that the decrease in light intensity and the occurrence of stray light can be suppressed. In this way, the light guide plate can suppress the deterioration of the quality of the displayed image.

[0044] The first wavelength component may be a wavelength component corresponding to red, and the second wavelength components may be a wavelength component corresponding to green and a wavelength component corresponding to blue.

[0045] According to the above aspect, the light guide plate guides light containing the three wavelength components of red, green, and blue by making the wavelength component corresponding to red incident on the first light guide and the wavelength components corresponding to green and blue incident on the second light guide, thereby contributing to displaying a full-color display image containing the above three wavelength components. Therefore, the light guide plate can further suppress deterioration in the quality of the full-color display image.

[0046] The light guide plate may further include a transparent member having the first deflection element and the second deflection element therein.

[0047] According to the above aspect, since the transparent member of the light guide plate supports the deflection element while transmitting light, the position of the deflection element can be maintained at an appropriate position with higher accuracy, and as a result, the optical path of the light deflected by the deflection element can be more appropriately maintained. This effect is particularly remarkable when the light guide plate is placed in an environment with vibration. This makes it possible to suppress deviation of the optical path of light caused by changes in the position of the deflection element, and suppress deterioration in the quality of the displayed image. Therefore, the light guide plate can further suppress deterioration in the quality of the displayed image.

[0048] The light guide plate may further include a third light guide and a third deflection element that causes light of a third wavelength component contained in the incident light to be incident on the third light guide.

[0049] According to the above aspect, the light guide plate selectively deflects the three wavelength components of the incident light by the deflection element, thereby causing the light to enter the three light guides, respectively, and thus suppresses the decrease in light intensity and the occurrence of stray light. In this way, the light guide plate can suppress the decrease in the quality of the displayed image.

[0050] The third deflection element may selectively deflect light of the third wavelength component contained in the incident light to cause the light to be incident on the third light guiding body.

[0051] According to the above aspect, the light guide plate allows the three wavelength components of the incident light to be incident on the three light guides by using the reflection by the deflection element, so that it is possible to suppress the decrease in light intensity and the occurrence of stray light. In this way, the light guide plate can suppress the decrease in the quality of the displayed image.

[0052] In addition, the first light guide may emit the light guided by the first light guide from a surface opposite to the surface into which the incident light is incident, and the second light guide may emit the light guided by the second light guide from a surface opposite to the surface into which the incident light is incident.

[0053] According to the above aspect, since the light guide plate emits light to the surface opposite to the surface where the incident light is incident, when a device that emits the incident light (e.g., an image generating device) and a device that receives the emitted light (e.g., a windshield) are present on the opposite side of the light guide plate, the light can be appropriately guided between the two devices. Therefore, the light guide plate can appropriately guide the light while suppressing deterioration in the quality of the displayed image.

[0054] In addition, the first light guide may emit the light guided by the first light guide from a surface on the same side as the surface on which the incident light is incident, and the second light guide may emit the light guided by the second light guide from a surface on the same side as the surface on which the incident light is incident.

[0055] According to the above aspect, since the light guide plate emits light to the same surface as the surface on which the incident light is incident, when a device that emits the incident light (e.g., an image generating device) and a device that receives the emitted light (e.g., a windshield) are present on the same side of the light guide plate, the light guide plate can appropriately guide the light between the two devices. Therefore, the light guide plate can appropriately guide the light while suppressing deterioration in the quality of the displayed image.

[0056] A display device according to an aspect of the present invention includes the above light guide plate and an image generating device that generates light representing an image and causes the light to enter the light guide plate.

[0057] According to the above aspect, the display device can suppress degradation in the quality of the displayed image by using the light guide plate.

[0058] Hereinafter, the embodiment will be specifically described with reference to the drawings.

[0059] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component arrangement and connection forms, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, components that are not described in an independent claim showing a top concept are described as optional components.

[0060] (Embodiment) In this embodiment, a light guide plate and a display device that suppress deterioration of the quality of a displayed image will be described. The light guide plate and the display device of this embodiment are a display device that displays an image by projecting it onto a windshield of a vehicle. In the following description, the XYZ axes shown in the figure may be used.

[0061] Fig. 4 is a schematic diagram showing the configuration of a light guide plate 10 according to the present embodiment. Fig. 4(a) is a diagram showing the configuration when the light guide plate 10 is viewed from above, that is, when viewed from the positive direction of the Z axis. Fig. 4(b) is a diagram showing the configuration when the light guide plate 10 is viewed from the side, that is, when viewed from the negative direction of the Y axis. Fig. 4(c) is a diagram showing the configuration when the light guide plate 10 is viewed from the side, that is, when viewed from the positive direction of the X axis.

[0062] 4, the light guide plate 10 includes an incident portion 10E and light guides 10A, 10B, and 10C (also referred to as light guides 10A, etc.). The light guides 10A, etc. are arranged in a parallel orientation and are arranged at overlapping positions when viewed from above. The light guides 10A, etc. have the same shape, for example, a rectangular shape, when viewed from above, but are not limited thereto.

[0063] Fig. 4(a) shows only the light guide 10A among the light guides 10A etc. The same explanation as for Fig. 4(a) also applies to the light guides 10B and 10C.

[0064] 4, light guide 10A is a plate having transparent member 15 and hologram elements 12A and 13A (also referred to as hologram element 12A, etc.) inside or on the surface of transparent member 15. Light guide 10A guides incident light L1 by total reflection inside light guide 10A, and emits light deflected by diffraction by hologram element 12A, etc. to the outside of light guide 10A as light L3A. Transparent member 15 is made of glass, resin, or the like.

[0065] Light L1 incident on incident portion 10E is light traveling in the positive Y-axis direction and the positive Z-axis direction. It is assumed that light L1 is display light generated by image generating device 17. Light guide plate 10 is installed in a position and attitude such that light L1 is incident on incident portion 10E at an appropriate angle as shown in FIG. 4 when display device 1 is in use (i.e., when display device 1 is installed as shown in FIG. 2).

[0066] The incident portion 10E has deflection elements 30A, 30B, and 30C (also referred to as deflection element 30A, etc.). The incident portion 10E deflects the light L1 by the deflection element 30A, etc., and causes the light L1 to be incident on the light guide 10A, etc. The incident portion 10E is a columnar body (e.g., a rectangular parallelepiped) having a width that includes the range in which the light guide 10A, etc. are present in the traveling direction of the light L1.

[0067] The deflection element 30A is a deflection element that allows light of a predetermined wavelength component (also referred to as a first wavelength component) included in the incident light to enter the light guide 10A. The deflection element 30A selectively deflects the light of the first wavelength component included in the incident light to enter the light guide 10A. More specifically, the deflection element 30A is a deflection element that selectively reflects the light of the first wavelength component included in the incident light to allow it to enter the light guide 10A, and transmits light other than the first wavelength component included in the incident light. The deflection element 30A can be realized by a wavelength-selective mirror (dichroic mirror).

[0068] The deflection element 30A deflects the light L1 that enters the light guide plate 10 from the outside to the inside, turning it into light L12A, which propagates inside the light guide 10A. The light L12A travels in the negative direction of the X-axis. The light L12A propagates inside the light guide 10A in the negative direction of the X-axis by repeatedly undergoing total reflection at the interface between the transparent member 15 and the air. The deflection element 30A deflects the light L1 so that the angle of incidence of the light L12A on the interface becomes larger than the critical angle.

[0069] The deflection element 30B is a deflection element that allows light of a predetermined wavelength component (also called a second wavelength component) included in the incident light to enter the light guide 10B. The deflection element 30B selectively deflects the light of the second wavelength component included in the incident light to enter the light guide 10B. More specifically, the deflection element 30B is a deflection element that selectively reflects the light of the second wavelength component included in the incident light to allow it to enter the light guide 10B and transmits light other than the second wavelength component included in the incident light. The deflection element 30B can be realized by a wavelength-selective mirror (dichroic mirror). The second wavelength component is different from the first wavelength component.

[0070] Deflection element 30B deflects light L1B that has passed through deflection element 30A to become light L12B, which propagates inside light guide 10B. Light L12B travels in the negative direction of the X-axis. Light L12B propagates in the negative direction of the X-axis inside light guide 10B by repeatedly undergoing total reflection at the interface between transparent member 15 and air. Deflection element 30B deflects light L1B so that the angle of incidence of light L12B on the interface becomes larger than the critical angle.

[0071] The deflection element 30C is a deflection element that allows light of a predetermined wavelength component (also called a third wavelength component) included in the incident light to enter the light guide 10C. The deflection element 30C selectively deflects the light of the third wavelength component included in the incident light to enter the light guide 10C. More specifically, the deflection element 30C is a deflection element that reflects the light of the third wavelength component included in the incident light to enter the light guide 10C and transmits light other than the third wavelength component included in the incident light. The deflection element 30C can be realized by a wavelength-selective mirror (dichroic mirror). The third wavelength component is different from both the first wavelength component and the second wavelength component.

[0072] Deflection element 30C deflects light L1C that has passed through deflection element 30B to become light L12C, which propagates inside light guide 10C. Light L12C travels in the negative direction of the X-axis. Light L12C propagates in the negative direction of the X-axis inside light guide 10C by repeatedly undergoing total reflection at the interface between transparent member 15 and air. Deflection element 30C deflects light L1C so that the angle of incidence of light L12C on the interface becomes larger than the critical angle.

[0073] The deflection elements 30A and the like deflect the light beams L1, L1B, and L1C by reflection or transmission, in other words, without using diffraction, so that there is no variation in the diffraction angle for each frequency, and therefore no light beams equivalent to the stray light beams LA, LB, and LC in FIG.

[0074] Light guide 10A includes holographic elements 12A and 13A. Light guide 10B includes holographic elements 12B and 13B. Light guide 10C includes holographic elements 12C and 13C.

[0075] Holographic elements 12A, 12B, 12C, 13A, 13B, and 13C are the same as the holographic elements of the same name provided in light guide plate 90, and contribute to the emission of light L3 in the same manner as in light guide plate 90.

[0076] The light guide plate 10 is installed in a position and orientation such that, when the display device 1 is in use, the emitted light L3 is directed toward the windshield 20. After being emitted from the light guide plate 10, the light L3 is reflected by the windshield 20 and enters the eye of the user U.

[0077] Although the light L1 incident on the light guide plate 10 has been described as including a plurality of wavelength components, this configuration can also be applied to the case where a plurality of incident lights each including a plurality of wavelength components individually are incident on the light guide plate 10. In that case, the deflection elements 30A, 30B, and 30C are required to be disposed at positions and attitudes that cause the light L12A, L12B, and L12C to be incident on the light guides 10A, 10B, and 10C at the angles shown in FIG.

[0078] FIG. 5 is a schematic diagram showing a first example of the configuration of the incidence section 10E according to the present embodiment.

[0079] Incident section 10E shown in FIG. 5 includes deflection elements 30A, 30B, and 30C, and transparent member 15. As shown in FIG.

[0080] Transparent member 15 has deflection elements 30A, 30B, and 30C therein. Transparent member 15 supports deflection elements 30A, etc. such that deflection elements 30A, etc. are positioned and oriented to reflect light beams L1, L1B, and L1C at appropriate angles.

[0081] It can be said that deflection elements 30A, 30B, and 30C are embedded inside transparent member 15. It can also be said that the space inside incidence portion 10E excluding deflection elements 30A, 30B, and 30C is filled with transparent member 15.

[0082] With this configuration, the incident section 10E can guide the light beams L1, L1B, and L1C using the deflection element 30A and the like that are supported in an appropriate position and attitude with higher precision by the transparent member 15, and can more appropriately maintain the optical path of the guided light. This effect is particularly noticeable when the light guide plate 10 is placed in an environment where vibrations occur.

[0083] 6 is a schematic diagram showing a second example of the configuration of the incident section 10E according to the present embodiment. The incident section 10E shown in FIG. 6 shows a configuration different from that of the incident section 10E shown in FIG.

[0084] Incident section 10E shown in FIG. 6 includes deflection elements 30A, 30B, and 30C, and a support member (not shown).

[0085] The incident portion 10E is hollow. The deflection elements 30A, 30B, and 30C are supported by appropriate support members so as to take positions and attitudes in the space 40 inside the incident portion 10E such that the light beams L1, L1B, and L1C are reflected at appropriate angles.

[0086] With this configuration, the entrance portion 10E can guide the light beams L1, L1B, and L1C using the deflection element 30A and the like supported at an appropriate position and posture. In addition, there is an advantage that an increase in weight can be suppressed.

[0087] (Modification of the embodiment) FIG. 7 is a schematic diagram showing the configuration of a light guide plate 50 as a first example of the configuration of a light guide plate according to this modified example.

[0088] Light guide plate 50 shown in FIG. 7 includes incident portion 50E and light guides 10A and 10B.

[0089] Incident portion 50E has deflection elements 30A and 30B.

[0090] Light L1 incident on light guide plate 50, that is, incident portion 50E, travels in the positive Y-axis direction and the positive Z-axis direction, and enters light guide plate 50 from the surface of light guide plate 50 on the negative Z-axis direction side.

[0091] The deflection element 30A is a deflection element that selectively deflects light of a predetermined wavelength component (also called a first wavelength component) contained in the incident light L1 to cause it to enter the light guide 10A. The deflection element 30A corresponds to a first deflection element. The deflection element 30A is similar to the deflection element 30A in the above embodiment.

[0092] The deflection element 30B is a deflection element that selectively deflects light of a predetermined wavelength component (also called a second wavelength component) contained in the incident light L1 to cause the light to enter the light guide 10B. The deflection element 30B corresponds to a second deflection element. The deflection element 30B is the same as the deflection element 30B in the above embodiment.

[0093] In this way, light guide 10A emits the light guided by light guide 10A from the surface opposite to the surface into which light L1 is incident (i.e., the surface on the negative Z-axis direction side). Light guide 10B emits the light guided by light guide 10B from the surface opposite to the surface into which light L1 is incident.

[0094] The incident light L1 is, for example, light having wavelength components corresponding to two colors (for example, red and green). In this case, the deflection element 30A, for example, deflects the light having a wavelength component corresponding to red, so that the light enters the light guide 10A, and transmits the light having a wavelength component corresponding to green. The deflection element 30B, for example, deflects the light having a wavelength component corresponding to green, so that the light enters the light guide 10B. In this way, the light guide plate 50 can display a display image using red and green lights. The same explanation is valid even if the above red and green are interchanged. The above two colors may be red and blue, or green and blue.

[0095] Furthermore, the incident light L1 may be, for example, light having wavelength components corresponding to three colors (for example, red, green, and blue).

[0096] In this case, the deflection element 30A, for example, deflects light having a wavelength component corresponding to red so that it enters the light guide 10A, and transmits light having wavelength components corresponding to green and blue. The deflection element 30B, for example, deflects light having a wavelength component corresponding to green and blue so that it enters the light guide 10B. In this way, a display image using red, green, and blue light can be displayed.

[0097] Also, the deflection element 30A may deflect light having a wavelength component corresponding to blue, for example, to enter the light guide 10A, and transmit light having wavelength components corresponding to green and red. In this case, the deflection element 30B deflects light having a wavelength component corresponding to green and red, for example, to enter the light guide 10B. In this way, a display image using red, green, and blue light can be displayed.

[0098] FIG. 8 is a schematic diagram showing the configuration of a light guide plate 51 as a second example of the configuration of the light guide plate according to this modified example.

[0099] Light guide plate 51 shown in FIG. 8 includes an incident portion 50F and light guides 10A and 10B.

[0100] Entrance portion 50F has deflection elements 30D and 30E.

[0101] Light L1 incident on light guide plate 51, that is, incident portion 50F, travels in the positive Y-axis direction and the negative Z-axis direction, and enters light guide plate 51 from the surface of light guide plate 51 on the positive Z-axis direction side.

[0102] The deflection element 30D is a deflection element that causes light of a predetermined wavelength component (also called a first wavelength component) contained in the light L1, which is the incident light, to enter the light guide 10A. The deflection element 30D corresponds to a first deflection element. The deflection element 30D has the same configuration as the deflection element 30A of the above-mentioned light guide plate 50, but the position and posture thereof may be different.

[0103] The deflection element 30E is a deflection element that causes light of a predetermined wavelength component (also called a second wavelength component) contained in the incident light L1 to enter the light guide 10B. The deflection element 30E corresponds to a second deflection element. The deflection element 30E has the same configuration as the deflection element 30B of the above-mentioned light guide plate 50, but the position and posture thereof may be different.

[0104] In this configuration, light guide 10A emits the light guided by light guide 10A from the same surface (i.e., the surface on the Z-axis positive direction) as the surface into which light L1 is incident (i.e., the surface on the Z-axis positive direction). Light guide 10B emits the light guided by light guide 10B from the same surface as the surface into which light L1 is incident.

[0105] FIG. 9 is a schematic diagram showing the configuration of a light guide plate 52 as a third example of the configuration of the light guide plate according to this modified example.

[0106] Light guide plate 52 shown in FIG. 9 includes an entrance portion 50G and light guides 10A and 10B.

[0107] Incident portion 50G has deflection elements 30F and 30G.

[0108] Light L1 incident on light guide plate 52, that is, incident portion 50G, travels in the negative X-axis direction and the positive Z-axis direction, and enters light guide plate 52 from the surface of light guide plate 52 on the positive X-axis direction side.

[0109] The deflection element 30F is a deflection element that causes light of a predetermined wavelength component (also called a first wavelength component) contained in the light L1, which is the incident light, to enter the light guide 10A. The deflection element 30F transmits the light of the predetermined wavelength component to cause it to enter the light guide 10A, and deflects light other than the predetermined wavelength component to travel toward the deflection element 30G. The deflection element 30F corresponds to a first deflection element. The deflection element 30F has the same configuration as the deflection element 30A of the light guide plate 50 described above, but the position and posture thereof may be different.

[0110] The deflection element 30G is a deflection element that causes light of a predetermined wavelength component (also called a second wavelength component) contained in the incident light L1 to enter the light guide 10B. The deflection element 30G corresponds to a second deflection element. The deflection element 30G has the same configuration as the deflection element 30B of the above-mentioned light guide plate 50, but the position and posture thereof may be different.

[0111] In this configuration, light guide 10A emits the light guided by light guide 10A from a surface that is neither the same side nor the opposite side (i.e., the surface on the positive side of the Z axis) to the surface into which light L1 is incident (i.e., the surface on the positive side of the X axis). Light guide 10B emits the light guided by light guide 10B from a surface that is neither the same side nor the opposite side to the surface into which light L1 is incident.

[0112] As described above, the light guide plate in the above embodiment or modification selectively deflects the two wavelength components of the incident light by the deflection element, thereby causing the light to enter the two light guides, respectively, and thus suppresses the decrease in light intensity and the occurrence of stray light. In this way, the light guide plate can suppress the decrease in the quality of the displayed image.

[0113] In addition, the light guide plate allows the two wavelength components of the incident light to be incident on the two light guides by using the reflection by the deflection element, so that the decrease in light intensity and the occurrence of stray light can be suppressed. In this way, the light guide plate can suppress the deterioration of the quality of the displayed image.

[0114] Moreover, the light guide plate guides light containing the three wavelength components of red, green, and blue by making the wavelength component corresponding to red incident on the first light guide and the wavelength components corresponding to green and blue incident on the second light guide, thereby contributing to displaying a full-color display image containing the above three wavelength components. Thus, the light guide plate can further suppress deterioration in the quality of the full-color display image.

[0115] Furthermore, since the light guide plate supports the deflection element while transmitting light through the transparent member, the position of the deflection element can be maintained at an appropriate position with higher accuracy, and as a result, the optical path of the light deflected by the deflection element can be more appropriately maintained. This effect is particularly noticeable when the light guide plate is placed in an environment with vibration. This makes it possible to suppress deviation of the optical path of light caused by changes in the position of the deflection element, and suppress deterioration in the quality of the displayed image. Therefore, the light guide plate can further suppress deterioration in the quality of the displayed image.

[0116] In addition, the light guide plate selectively deflects the three wavelength components of the incident light with the deflection element, causing the light to enter the three light guides, respectively, thereby suppressing the decrease in light intensity and the occurrence of stray light. In this way, the light guide plate can suppress the decrease in the quality of the displayed image.

[0117] In addition, the light guide plate allows the three wavelength components of the incident light to be incident on the three light guides by using the reflection of the deflection element, so that the decrease in light intensity and the occurrence of stray light can be suppressed. In this way, the light guide plate can suppress the deterioration of the quality of the displayed image.

[0118] In addition, since the light guide plate emits light to the surface opposite to the surface where the incident light is incident, when a device that emits the incident light (e.g., an image generating device) and a device that receives the emitted light (e.g., a windshield) are present on the opposite side of the light guide plate, the light guide plate can appropriately guide the light between the two devices. Therefore, the light guide plate can appropriately guide the light while suppressing deterioration in the quality of the displayed image.

[0119] In addition, since the light guide plate emits light to the same surface as the surface on which the incident light is incident, when a device that emits the incident light (e.g., an image generating device) and a device that receives the emitted light (e.g., a windshield) are on the same side of the light guide plate, the light guide plate can appropriately guide the light between the two devices. Therefore, the light guide plate can appropriately guide the light while suppressing deterioration in the quality of the displayed image.

[0120] Furthermore, the display device can suppress deterioration in the quality of the displayed image by using the light guide plate.

[0121] Although the light guide plate according to one or more aspects has been described based on the embodiment, the present invention is not limited to this embodiment. As long as it does not deviate from the spirit of the present invention, various modifications conceived by a person skilled in the art to this embodiment and forms constructed by combining components in different embodiments may also be included within the scope of one or more aspects. [Industrial Applicability]

[0122] The present invention can be used in a head-up display device of a vehicle, etc. [Explanation of symbols]

[0123] 1 Display device 5. Vehicles 10, 50, 51, 52, 90 light guide plate 10A, 10B, 10C, 90A, 90B, 90C light guide 10E, 50E, 50F, 50G entrance section 12A, 12B, 12C, 13A, 13B, 13C, 91A, 91B, 91C Hologram elements 14 Virtual Image 15 Transparent materials 17 Image generation device 20 Windshield 30A, 30B, 30C, 30D, 30E, 30F, 30G deflection element 40 space L1, L1B, L1C, L12A, L12B, L12C, L23A, L23B, L23C, L3, L3A, L3B, L3C, L5, LA, LB, LC light U User

Claims

1. A light guide plate, The light guide plate is provided in a head-up display including an image generating device that generates light representing an image and causes the light to enter the light guide plate, A first light guide; A second light guide; a first deflection element that selectively deflects light of a first wavelength component included in the incident light to cause the light to enter the first light guiding body; a second deflection element that selectively deflects light of a second wavelength component included in the incident light to cause the light to be incident on the second light guiding body; an entrance portion having the first deflection element and the second deflection element in one transparent member, the incident portion is provided separately from the first light guide and the second light guide, the first deflection element and the second deflection element are provided to have an inclination angle with respect to each of the light guides that deflect the incident light and make the light incident thereto; the first light guide and the second light guide are arranged in parallel and overlap each other when viewed from a normal direction of the first light guide or the second light guide, The direction in which the light travels within the incident portion is a direction intersecting both a plane in which the first light guide is disposed and a plane in which the second light guide is disposed. light guide plate.

2. the first deflection element selectively reflects light of the first wavelength component contained in the incident light to cause it to enter the first light guiding body and transmits light other than the first wavelength component contained in the incident light; The second deflection element selectively reflects light of the second wavelength component contained in the incident light to cause the light to enter the second light guide, and transmits light other than the second wavelength component contained in the incident light. The light guide plate according to claim 1 .

3. the first wavelength component is a wavelength component corresponding to red, The second wavelength component is a wavelength component corresponding to green and a wavelength component corresponding to blue. The light guide plate according to claim 1 .

4. The light guide plate further comprises: A support member that supports the positions and attitudes of the first deflection element and the second deflection element is provided. The light guide plate according to any one of claims 1 to 3.

5. The light guide plate further comprises: A third light guiding body; a third deflection element that causes light of a third wavelength component contained in the incident light to enter the third light guiding body. The light guide plate according to any one of claims 1 to 4.

6. The third deflection element selectively deflects the light of the third wavelength component contained in the incident light, thereby causing the light to be incident on the third light guiding body. The light guide plate according to claim 5 .

7. the first light guide emits the light guided by the first light guide from a surface opposite to a surface into which the incident light is incident, The second light guide emits the light guided by the second light guide from a surface opposite to a surface into which the incident light is incident. The light guide plate according to any one of claims 1 to 6.

8. the first light guide emits the light guided by the first light guide from a surface on the same side as a surface into which the incident light is incident, The second light guide emits the light guided by the second light guide from a surface on the same side as the surface into which the incident light is incident. The light guide plate according to any one of claims 1 to 6.

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