Image display system

Abstract

A video display system includes a light source unit and a drive unit. The light source unit has a display device and an imaging optical system. The display device can display images. The imaging optical system projects a first image corresponding to the image onto a projection unit, and causes an image recognizable by a recognizer to be displayed on the opposite side of the projection unit as seen from the recognizer. The drive unit changes the position of the first image by controlling the position and / or orientation of the light source unit on the basis of a status signal input from the outside.

Description

Technical Field

[0001] Embodiments of the present invention relate to an image display system. Background Art

[0002] Patent document 1 discloses a technology in which light emitted from a display device capable of displaying an image is sequentially reflected by a plurality of reflectors, and the light reflected by the last reflector is further reflected toward a user by a reflective member such as a windshield, so that the user can recognize a virtual image corresponding to the image displayed by the display device. However, in the technology disclosed in patent document 1, the position of the virtual image as seen by the user is fixed.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2016 / 208195 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] An object of an embodiment of the present invention is to provide an image display system capable of changing the position of a virtual image.

[0008] Technical solutions for solving technical problems

[0009] An embodiment of the present invention provides an image display system, which includes a light source unit and a driving unit. The light source unit has a display device and an imaging optical system. The display device can display an image. The imaging optical system projects a first image corresponding to the image onto a projection unit so that an image that can be recognized by a viewer appears to be displayed on the opposite side of the projection unit from the viewer. The driving unit changes the position of the first image by controlling the position and / or orientation of the light source unit based on a status signal input from the outside.

[0010] Effects of the Invention

[0011] According to the embodiment of the present invention, it is possible to realize a video display system capable of changing the position of a virtual image. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a top view showing the image display system according to the first embodiment.

[0013] Figure 2 This is an end view showing the image display system according to the first embodiment.

[0014] Figure 3 This is an end view showing the display device of the image display system according to the first embodiment.

[0015] Figure 4 It is a schematic diagram showing the scene observed by the recognizer in the driver's seat.

[0016] Figure 5 It is a diagram showing the contents displayed by the video display system according to the first embodiment.

[0017] Fig. 6A It is a schematic diagram showing the principle of the light source unit according to the first embodiment.

[0018] Figure 6B It is a schematic diagram showing the principle of the light source unit of the reference example.

[0019] Fig. 7A It is a graph showing the light distribution pattern of light emitted from one light emitting area in Examples 1 and 11, Reference Example, and LCD.

[0020] Figure 7B It is a graph showing the uniformity of the brightness of the second image in Examples 1 to 12 and the reference example.

[0021] Figure 8 It is a top view showing the image display system according to the second embodiment.

[0022] Fig. 9 It is an end view showing the image display system according to the second embodiment.

[0023] Fig.10 It is a schematic diagram showing the scene observed by the recognizer in the driver's seat.

[0024] Fig.11 It is an end view showing the image display system according to the third embodiment.

[0025] Fig.12 Yes Fig.11 The display device and the reflective polarization element are shown in a partially enlarged cross-sectional view.

[0026] Fig.13 This is an end view showing a display device in a modified example of the third embodiment.

[0027] Fig.14 It is a perspective view showing a reflection type polarization element in a modification of the third embodiment.

[0028] Fig.15 It is a side view showing a light source unit according to a fourth embodiment.

[0029] Fig.16 It is a side view showing a light source unit according to a modification of the fourth embodiment. DETAILED DESCRIPTION

[0030] Hereinafter, each embodiment and its modified examples will be described with reference to the accompanying drawings. It should be noted that the accompanying drawings are schematic or conceptual drawings, and are appropriately enhanced or simplified. For example, the relationship between the thickness and width of each part, the ratio of the size between the parts, etc. may not be the same as in reality. In addition, even when representing the same part, there are cases where the sizes and ratios of each other are represented differently depending on the drawings. In addition, in this specification and the drawings, the same reference numerals are marked for the elements that are the same as the elements described in the drawings that have been given, and the detailed description is appropriately omitted.

[0031] <First embodiment>

[0032] First, the first embodiment will be described.

[0033] Figure 1 It is a top view showing the image display system according to this embodiment.

[0034] Figure 2 It is an end view showing the image display system according to the present embodiment.

[0035] like Figure 1 and Figure 2 As shown, the image display system 10 of the present embodiment includes a light source unit 11, a reflection unit 12, and a drive unit 15. The light source unit 11 has a display device 110 and an imaging optical system 120. The display device 110 can display an image. The imaging optical system 120 projects a first image IM1 corresponding to the image displayed by the display device 110 onto a projection unit described later, so that a second image IM2 that can be identified by an identifier 14 appears to be displayed on the opposite side of the projection unit from the identifier 14. In the present embodiment, the projection unit is the front windshield 13a of the vehicle 13. However, the projection unit can also be a combiner. The drive unit 15 changes the position of the first image IM1 by controlling the position and / or orientation of the light source unit 11 based on a status signal S input from the outside. The first image IM1 is a real image, that is, an intermediate image. The second image IM2 is a virtual image larger than the first image IM1.

[0036] Specifically, the image display system 10 is mounted on, for example, a car 1000 to form a HUD (Head Up Display). The car 1000 includes a vehicle 13, a condition detection unit 16 that detects the internal and / or external conditions of the vehicle 13 and outputs the detection result, and the image display system 10 fixed to the vehicle 13. The identifier 14 is a passenger of the car 1000, for example, a driver.

[0037] The display device 110 of the light source unit 11 displays an image that the identifier 14 wants to recognize through the HUD. The image is a character string and / or a graphic. A specific example of the display device 110 and the image will be described later. The imaging optical system 120 of the light source unit 11 outputs the light emitted from the display device 110 to the reflection unit 12, and forms a first image IM1 between the light source unit 11 and the reflection unit 12. The reflection unit 12 reflects the light emitted from the light source unit 11 toward the front windshield 13a of the vehicle 13. The front windshield 13a includes, for example, glass.

[0038] The front windshield 13a reflects the light reaching from the reflection unit 12 on its inner surface and makes it incident on the eye movement range 14a of the recognizer 14. Thus, the recognizer 14 can recognize the second image IM2 corresponding to the image displayed by the display device 110. It should be noted that the "eye movement range" refers to the range in the space in front of the recognizer's eyes where the virtual image can be recognized.

[0039] The condition detection unit 16 is, for example, an adaptive front-lighting system (AFS). AFS is a system that detects the amount of rotation of the steering wheel of the vehicle 13 and, based on the amount of rotation, directs the optical axis of the headlight toward the direction of travel of the vehicle 13 when turning. In this case, the output signal S0 of the condition detection unit 16 represents the direction of travel of the vehicle 13. In addition, the condition detection unit 16 may be, for example, an eye tracking system that detects the direction of the line of sight of the identifier 14. In this case, the output signal S0 represents the direction of the line of sight of the identifier 14. In addition, the condition detection unit 16 may be, for example, an external sensor that detects objects outside the vehicle 13. External objects are, for example, pedestrians or other vehicles that run out of the road. In this case, the output signal S0 represents the direction from the vehicle 13 toward objects outside the vehicle 13.

[0040] It should be noted that the condition detection unit 16 is not limited to the above example, and can detect the internal or external conditions of the vehicle 13 and output the detection result as the output signal S0. In addition, the condition detection unit 16 may also include a plurality of detection devices. For example, the condition detection unit 16 may also include two or all of the AFS, the eye tracking system, and the external sensor.

[0041] A status signal S based on the output signal S0 of the status detection unit 16 is input to the drive unit 15. The status signal S may be directly input to the drive unit 15 from the status detection unit 16, or may be input via an onboard computer or the like. When the status signal S is directly input from the status detection unit 16, the output signal S0 of the status detection unit 16 is the status signal S. When the status signal S is input via an onboard computer or the like, the status signal S and the output signal S0 may differ in form, rate, or attached information, but the information transmitted is related. In addition, when the status detection unit 16 includes a plurality of detection devices, the onboard computer may also generate the status signal S by comprehensively judging the contents of the plurality of output signals S0.

[0042] The driving unit 15 controls the position and / or orientation of the light source unit 11 based on the status signal S. For example, the driving unit 15 controls the orientation of the light source unit 11 with the axis CR as the rotation axis based on the status signal S. The axis CR preferably extends in the up-down direction of the vehicle 13, and preferably passes through the eye movement range 14a of the identifier 14 or its vicinity. More preferably, the axis CR coincides with the axis of the eye movement range 14a. The driving unit 15 includes, for example, a stepping motor. The driving unit 15 changes the position of the first image IM1 by controlling the orientation of the light source unit 11.

[0043] For example, when the situation detection unit 16 is an AFS and the situation signal S indicates the direction of travel of the vehicle 13, the drive unit 15 sets the direction in which the light source unit 11 projects the first image IM1 (hereinafter referred to as the "emission direction") to the direction corresponding to the direction of travel of the vehicle 13. In addition, when the situation detection unit 16 is an eye tracking system and the situation signal S indicates the direction of sight of the recognizer 14, the drive unit 15 sets the emission direction to the direction corresponding to the direction of sight. In addition, when the situation detection unit 16 is an external sensor and the situation signal S indicates the direction from the vehicle 13 to an object outside the vehicle 13, the drive unit 15 sets the emission direction to the direction corresponding to the direction toward the object.

[0044] For example, the driving unit 15 selects a position of the first image IM1 from three locations. Regardless of the position of the first image IM1, the reflecting unit 12 and the front windshield 13a can reflect the light emitted from the light source unit 11 toward the eye movement range 14a of the identifier 14. As a result, the position of the second image IM2 observed by the identifier 14 changes in conjunction with the position of the first image IM1. As a result, for example, the position at which the second image IM2 can be observed from the identifier 14 is selected from three positions PA, PB, and PC. For example, as viewed from the identifier 14, position PA is at the front left, position PB is at the front front, and position PC is at the front and right. It should be noted that the position at which the second image IM2 can be displayed is not limited to three, but may be two or more than four. In addition, the arrangement of the positions that can be displayed may be equally spaced or unequally spaced.

[0045] Next, the detailed structure of the image display system 10 will be described.

[0046] Figure 3 This is an end view showing a display device of the image display system according to the present embodiment.

[0047] In order to facilitate the understanding of the description, the configuration and structure of each part are described below using the XYZ orthogonal coordinate system. In the present embodiment, the front-to-back direction of the vehicle 13 is set as the "X direction", the left-to-right direction of the vehicle 13 is set as the "Y direction", and the up-down direction of the vehicle 13 is set as the "Z direction". The XY plane is a horizontal plane of the vehicle 13. The direction of the arrow in the X direction (front) is called the "+X direction", and the opposite direction (rear) is also called the "-X direction". In addition, the direction of the arrow in the Y direction (left) is called the "+Y direction", and the opposite direction (right) is also called the "-Y direction". In addition, the direction of the arrow in the Z direction (upward) is called the "+Z direction", and the opposite direction (downward) is also called the "-Z direction".

[0048] In addition, Figure 2 , the position where the first image IM1 is formed is indicated by a circular mark. In addition, similarly to the first image IM1, the position where the second image IM2 is formed is indicated by a circular mark. On the other hand, the position where the principal light ray L of each mark reaching the first image IM1 is emitted in the display device 110 is indicated by a quadrilateral mark. In this way, in order to facilitate the understanding of the description, the emission position on the display device 110 of each principal light ray L is indicated by a mark different from the imaging position of the first image IM1 and the formation position of the second image IM2, but the image displayed on the display device 110, the first image IM1, and the second image IM2 are roughly similar.

[0049] (Light source unit)

[0050] The display device 110 of the light source unit 11 is an LED display. In the display device 110 , a plurality of LED elements 112 are arranged in a matrix. One or more LED elements 112 correspond to each pixel of the display device 110 .

[0051] like Figure 3 As shown, in the display device 110, each LED element 112 is mounted face-down on the substrate 111. However, each LED element may be mounted face-up on the substrate. Each LED element 112 includes a semiconductor stack 112a, an anode electrode 112b, and a cathode electrode 112c.

[0052] The semiconductor stack 112a includes a p-type semiconductor layer 112p1, an active layer 112p2 disposed on the p-type semiconductor layer 112p1, and an n-type semiconductor layer 112p3 disposed on the active layer 112p2. X Al Y Ga 1－X－Y A gallium nitride compound semiconductor represented by N (0≤X, 0≤Y, X+Y<1). In the present embodiment, the light emitted by the LED element 112 is visible light.

[0053] The anode electrode 112b is electrically connected to the p-type semiconductor layer 112p1. The anode electrode 112b is electrically connected to the wiring 118b. The cathode electrode 112c is electrically connected to the n-type semiconductor layer 112p3. The cathode electrode 112c is electrically connected to another wiring 118a. Each electrode 112b and 112c can be made of, for example, a metal material.

[0054] In this embodiment, a plurality of recesses 112t are provided on the light emitting surface 112s of each LED element 112. In this specification, the "light emitting surface of the LED element" refers to a surface of the surface of the LED element from which light incident on the imaging optical system 120 is mainly emitted. In this embodiment, the surface of the n-type semiconductor layer 112p3 located on the opposite side to the surface facing the active layer 112p2 corresponds to the light emitting surface 112s.

[0055] Hereinafter, the optical axis of the light emitted from each pixel 110p will be referred to as the "optical axis C". The optical axis C is, for example, a straight line connecting point a1 and point a2, where point a1 is the point with the highest brightness in the range illuminated by the light from one pixel 110p in a first plane P1 that is parallel to the XY plane in which the multiple pixels 110p are arranged and located on the light emission side of the display device 110, and point a2 is the point with the highest brightness in the range illuminated by the light from the pixel 110p in a second plane P2 that is parallel to the XY plane and separated from the first plane P1. When there are multiple points with the highest brightness, for example, the center point of these points may also be set as the point with the highest brightness. It should be noted that from a production point of view, it is preferred that the optical axis C is parallel to the Z axis.

[0056] By providing a plurality of recesses 112t on the light emitting surface 112s of each LED element 112, light emitted from each LED element 112, that is, light emitted from each pixel 110p, is as follows: Figure 3 Here, “the light emitted from each pixel has a substantially Lambertian light distribution” means that the light intensity in the direction at an angle θ relative to the optical axis C of each pixel can be approximated to cosine of the light intensity on the optical axis C with n being a value greater than 0. n Here, n is preferably less than 11, and more preferably 1. It should be noted that there are multiple planes including the optical axis C of the light emitted from one pixel 110p, but the light distribution pattern of the light emitted from the pixel 110p in each plane is a roughly Lambertian light distribution, and the value of n is also roughly the same.

[0057] like Figure 2 As shown, the imaging optical system 120 of the light source unit 11 is an optical system including all optical elements required to image the first image IM1 at a predetermined position. In this embodiment, there is an input element 121 on which the light emitted from the display device 110 is incident, an intermediate element 122 on which the light reflected by the input element 121 is incident, and an output element 123 on which the light reflected by the intermediate element 122 is incident. The light emitted from the output element 123 forms the first image IM1. It should be noted that as long as the light via the input element 121 is incident on the output element 123, the intermediate element 122 may not be provided.

[0058] The imaging optical system 120 has a substantially telecentric property on the first image IM1 side. Here, “the imaging optical system 120 has a substantially telecentric property on the first image IM1 side” means that Figure 2As shown, a plurality of principal light rays L emitted from different positions in the display device 110, passing through the imaging optical system 120 and reaching the first image IM1 are substantially parallel to each other before and after the first image IM1. Different positions are, for example, different pixels 110p of the display device 110. "A plurality of principal light rays L are substantially parallel to each other" means that they are substantially parallel within a practical range that allows for errors caused by manufacturing accuracy and assembly accuracy of components of the light source unit 11. In the case of "a plurality of principal light rays L are substantially parallel to each other", for example, the angle formed by the principal light rays L is less than 10 degrees.

[0059] When the imaging optical system 120 has a substantially telecentric property on the first image IM1 side, a plurality of principal light rays L intersect each other before being incident on the input element 121. Hereinafter, the point where the plurality of principal light rays L intersect each other is referred to as a "focus F". Therefore, whether the imaging optical system 120 has a substantially telecentric property on the first image IM1 side can be confirmed by, for example, utilizing the reversibility of light and by the following method. First, a light source capable of emitting parallel light such as a laser light source is arranged near the position where the first image IM1 is formed. The light emitted from the light source is irradiated onto the output element 123 of the imaging optical system 120. The light emitted from the light source and passing through the output element 123 is incident on the input element 121. Furthermore, when there is a point where the light emitted from the input element 121 converges before reaching the display device 110, that is, a focus F, it can be determined that the imaging optical system 120 has a substantially telecentric property on the first image IM1 side.

[0060] Since the imaging optical system 120 is substantially telecentric on the first image IM1 side, the imaging optical system 120 is mainly incident with light that has passed through the focal point F and its vicinity, among the light emitted from each pixel of the display device 110. Each optical element constituting the imaging optical system 120 will be described below.

[0061] The input element 121 is located on the −Z side of the display device 110 and is disposed to face the display device 110 . The input element 121 is a reflector having a concave reflective mirror surface 121 a . The input element 121 reflects light emitted from the display device 110 .

[0062] The intermediate element 122 is disposed on the −X side of the display device 110 and the input element 121 and faces the input element 121 . The intermediate element 122 is a reflector having a concave reflective mirror surface 122 a . The intermediate element 122 further reflects the light reflected by the input element 121 .

[0063] The input element 121 and the intermediate element 122 form a curved portion 120a that bends a plurality of principal rays L so that the plurality of principal rays L emitted from different positions of the display device 110 are substantially parallel to each other. In this embodiment, the reflective mirror surfaces 121a and 122a are biconical surfaces. However, the reflective mirror surface may be a part of a spherical surface or a free-form surface.

[0064] The output element 123 is configured to be located on the +X side of the display device 110 and the input element 121, and is opposite to the intermediate element 122. The output element 123 is a reflector having a flat reflective mirror surface 123a. The output element 123 reflects the light passing through the input element 121 and the intermediate element 122 toward the formation position of the first image IM1. Specifically, a plurality of principal light rays L that are approximately parallel to each other using the curved portion 120a are incident on the output element 123. The reflective mirror surface 123a is inclined relative to the horizontal plane of the vehicle 13, i.e., the XY plane, in a manner that the more it is toward the -Z direction, the more it is toward the +X direction. Thus, the output element 123 reflects the light reflected from the intermediate element 122 in a direction inclined relative to the Z direction in a manner that the more it is toward the -Z direction, the more it is toward the +X direction. As shown in FIG. Figure 2 As shown, the output element 123 constitutes a direction changing portion 120 b that changes the directions of the plurality of principal light rays L so that the plurality of principal light rays L that are substantially parallel to each other due to the curved portion 120 a are directed toward the formation position P of the first image IM1 .

[0065] In the present embodiment, the optical path between the input element 121 and the intermediate element 122 extends in a direction intersecting the XY plane. In addition, the optical path between the intermediate element 122 and the output element 123 extends in a direction along the XY plane. Since a portion of the optical path in the imaging optical system 120 extends in a direction intersecting the XY plane, the light source unit 11 can be miniaturized in the direction along the XY plane. In addition, since another portion of the optical path in the imaging optical system 120 extends in a direction along the XY plane, the light source unit 11 can be miniaturized in the Z direction.

[0066] In addition, the optical path between the display device 110 and the input element 121 intersects with the optical path between the intermediate element 122 and the output element 123. By making the optical paths intersect each other in the light source unit 11, the light source unit 11 can be miniaturized.

[0067] However, the optical paths in the light source unit are not limited to the above. For example, all the optical paths in the imaging optical system may extend along the XY plane or in a direction intersecting the XY plane. In addition, the optical paths in the light source unit may not intersect with each other.

[0068] The input element 121, the intermediate element 122, and the output element 123 may be respectively formed of a main body member made of glass or resin material, and a reflective film such as a metal film or a dielectric multilayer film provided on the surface of the main body member and constituting the reflective mirror surfaces 121a, 122a, 123a. In addition, the entirety of the input element 121, the intermediate element 122, and the output element 123 may be respectively formed of a metal material.

[0069] like Figure 2 As shown, in the present embodiment, the light source unit 11 is provided on the top 13b of the vehicle 13. The light source unit 11 is, for example, arranged on the inner side of the wall 13s1 exposed in the vehicle in the top 13b. A through hole 13h1 through which the light emitted from the output element 123 of the light source unit 11 can pass is provided on the wall 13s1. The light emitted from the output element 123 passes through the through hole 13h1 and irradiates the space between the identifier 14 and the front windshield 13a. However, the light source unit may be mounted on the top surface. A transparent or translucent cover with a small haze value may also be provided on the through hole 13h1. By providing the cover, dust and the like can be prevented from adhering to the optical unit. The light source unit can be prevented from being recognized from the through hole 13h1, and the design can be improved. The haze value is preferably 50% or less, and more preferably 20% or less. By setting the cover to such a haze value, a significant reduction in the brightness of the light emitted from the light source unit 11 and image disturbance can be suppressed, while the above-mentioned effects can be obtained.

[0070] The imaging optical system 120 has been described above, but the structure and position of the coupling optical system are not limited to the above as long as it has a substantially telecentric property on the first image side. For example, the number of optical elements constituting the direction changing section may be two or more.

[0071] (Reflection Unit)

[0072] like Figure 2 As shown, in the present embodiment, the reflection unit 12 includes a reflector 131 having a concave reflector surface 131a. The reflector 131 is configured to be opposite to the front windshield 13a. The reflector 131 reflects the light emitted from the output element 123 and irradiates the front windshield 13a. The reflector 131 can also be composed of a main body component composed of glass or resin materials, and a reflective film such as a metal film or a dielectric multilayer film provided on the surface of the main body component and constituting the reflector surface 131a. In addition, the entirety of the reflector 131 can also be composed of a metal material.

[0073] The reflector 131 is configured to allow light emitted from the light source unit 11 to be incident even if the driving unit 15 changes the orientation of the light source unit 11. The reflector 131 may be separately provided according to the positions PA, PB, PC of the second image IM2, or may be provided integrally. The curvature of the reflector surface 131a of the reflector 131 is set according to the positions PA, PB, PC of the second image IM2. The reflector surface 131a may be a continuous curved surface, or may be divided into three areas corresponding to the positions PA, PB, PC of the second image IM2, and boundaries may be formed between the areas. In one example, the reflector surface 131a is a biconical surface. However, the reflector surface may be a part of a spherical surface, or may be a free-form surface.

[0074] The light irradiated to the windshield 13a is reflected by the inner surface of the windshield 13a and enters the eye movement range 14a of the recognizer 14. Thus, the recognizer 14 recognizes the second image IM2 corresponding to the image displayed on the display device 110 at the position PA, PB or PC on the opposite side of the windshield 13a.

[0075] In the present embodiment, the reflection unit 12 is provided in the instrument panel portion 13c of the vehicle 13. The reflection unit 12 is, for example, arranged on the inner side of a wall 13s2 exposed inside the vehicle in the instrument panel portion 13c of the vehicle 13. The wall 13s2 is provided with a through hole 13h2 through which the light emitted from the output element 123 of the light source unit 11 can pass. The light emitted from the output element 123 passes through the through hole 13h1 to form a first image IM1, then passes through the through hole 13h2 and irradiates the reflection unit 12. However, the reflection unit may also be mounted on the upper surface of the instrument panel portion. In addition, the reflection unit may be arranged on the top, and the light source unit may be arranged on the instrument panel portion.

[0076] exist Figure 2 In the example shown, the path of light from the inner surface of the front windshield 13a toward the eye movement range 14a is approximately horizontal. That is, the path is approximately parallel to the XY plane. Moreover, in the present embodiment, the light source unit 11 is arranged above (in the +Z direction) and the reflection unit 12 is arranged below (in the -Z direction) with the XY plane including the path of the light as a reference. That is, the light source unit 11 and the reflection unit 12 are separated by the XY plane. However, the path of light from the inner surface of the front windshield 13a toward the eye movement range 14a may also be inclined instead of being approximately horizontal.

[0077] The above description is about the reflection unit 12, but the structure and position of the reflection unit are not limited to the above. For example, the number of optical elements such as reflectors constituting the reflection unit may be 2 or more. It should be noted that the reflection unit 12, for example, needs to be configured so that sunlight irradiated from the outside of the vehicle through the front windshield 13a is not reflected toward the eye movement range 14a.

[0078] Next, the operation of the image display system 10 according to the present embodiment will be described.

[0079] First, the operation of switching the display position of the second image IM2 will be described.

[0080] Figure 4 It is a schematic diagram showing the scene observed by the recognizer in the driver's seat.

[0081] Figure 5 It is a diagram showing the contents displayed by the image display system according to the present embodiment.

[0082] like Figure 1 to Figure 3 As shown, the situation detection unit 16 detects the situation inside and / or outside the vehicle 13 and outputs an output signal S0. The output signal S0 directly becomes the situation signal S, or the situation signal S is generated based on the output signal S0, and the situation signal S is input to the driving unit 15. The driving unit 15 controls the direction of the light source unit 11 based on the situation signal S. In this state, the display device 110 of the light source unit 11 displays an image. Based on the image, the imaging optical system 120 of the light source unit 11 forms a first image IM1 as a real image at a position P. In addition, the light forming the first image IM1 is reflected by the reflection unit 12 and the front windshield 13a, and is incident on the eye movement range 14a of the recognizer 14. As a result, the recognizer 14 recognizes the second image IM2 as a virtual image.

[0083] At this time, the position of the imaged first image IM1 changes approximately along the XY plane according to the orientation of the light source unit 11. In the present embodiment, for example, it is selected from three positions. As a result, the position of the second image IM2 recognized by the identifier 14 also changes. In the present embodiment, the position of the second image IM2 recognized by the identifier 14 is selected from the positions PA, PB, and PC.

[0084] Next, examples of display contents are described.

[0085] The image display system 10 may also display information indicating the driving state of the automobile 1000 , such as the speed.

[0086] like Figure 5 As shown in scene 1, when the car 1000 is moving straight, the image display system 10 displays the speed at a position PB corresponding to the front of the identifier 14. It should be noted that at this time, nothing is displayed at the positions PA and PC.

[0087] like Figure 5As shown in scene 2, when the recognizer 14, who is a driver, turns the steering wheel to the right, the AFS of the situation detection unit 16 detects this, and the image display system 10 switches the display to the position PC located in the right front of the recognizer 14. It should be noted that the eye tracking system of the situation detection unit 16 can also detect the direction of the recognizer's 14 line of sight and switch the display position.

[0088] In addition, the image display system 10 may also display navigation information, such as the radius of curvature (R) of a corner and the road conditions ahead of the corner. The navigation information can be obtained from a navigation system.

[0089] like Figure 5 As shown in scene 3, when turning right, the image display system 10 can also display the curvature radius (R) of the corner at position PC. In addition, a speeding warning can also be displayed based on the speed and the curvature radius.

[0090] like Figure 5 As shown in scene 4, when turning right, the image display system 10 can also display that there is a left corner in front of the right corner.

[0091] like Figure 5 As shown in scene 5, when the identifier 14 wants to turn left, the image display system 10 can also display that the left road is prohibited from entering.

[0092] In addition, the image display system 10 can also call attention to the conditions outside the vehicle, such as pedestrians rushing out or other vehicles that are about to be overtaken.

[0093] like Figure 5 As shown in scene 6, when the recognizer 14 is observing the right side, if a pedestrian rushes out from the left side or another vehicle is about to pass from the left side, the external sensor of the situation detection unit 16 detects this situation, and the image display system 10 displays the left side at the position PC entering the field of vision of the recognizer 14. Next, as shown in scene 7, the content that should be paid attention to can also be displayed at the position PA located in the left front of the recognizer 14. In this way, the sight line of the recognizer 14 can be guided. It should be noted that, when it is determined that the sight line of the recognizer 14 is dangerous, the content that should be paid attention to can also be displayed at the position PC, and nothing can be displayed at the position PA.

[0094] Next, the effects of this embodiment will be described.

[0095] In the present embodiment, the position of the virtual image (second image IM2 ) can be changed by the driving unit 15 controlling the orientation of the light source unit 11 based on the situation signal S. This can effectively assist the viewer 14 in driving the car.

[0096] In addition, in the present embodiment, since the imaging optical system 120 has a substantially telecentric property on the first image IM1 side, a compact and high-quality image can be displayed. This effect will be described in detail below.

[0097] Fig. 6A It is a schematic diagram showing the principle of the light source unit of this embodiment.

[0098] Figure 6B It is a schematic diagram showing the principle of the light source unit of the reference example.

[0099] exist Fig. 6A In FIG. 1 , the light distribution pattern of light emitted from two pixels 110 p among the plurality of pixels 110 p of the display device 110 of the present embodiment is indicated by a dotted line. Figure 6B In FIG. 1 , the light distribution pattern of light emitted from two pixels 2110p among the plurality of pixels 2110p of the display device 2110 of the reference example is indicated by a dotted line. Fig. 6A and Figure 6B In the figure, the imaging optical systems 120 and 2120 are simplified.

[0100] like Figure 6B As shown, in the light source unit 2011 of the reference example, the display device 2110 is a liquid crystal display device (Liquid Crystal Display: LCD) including a plurality of pixels 2110p. Figure 6B As shown by the dotted line in the middle, the light emitted from each pixel 2110p is mainly distributed in the normal direction of the light emission surface 2110s. In addition, there are multiple planes including the optical axis of the light emitted from a pixel 2110p, but in the display device 2110 as an LCD, the light distribution pattern of the light emitted from a pixel 2110p in each plane is different from each other. Moreover, in one plane among the multiple planes, the light emitted from each pixel 2110p has a luminous intensity in the direction at an angle θ relative to the optical axis, which is cosine of the luminous intensity on the optical axis. 20 The light distribution pattern is approximately theta times.

[0101] In such a display device 2110, even if it is light emitted from the same position of the display device 2110, the luminance and chromaticity vary depending on the angle at which the viewer observes. Therefore, assuming that the imaging optical system 2120 takes in light emitted from each pixel 2110p in a direction other than the normal direction, even if the luminance of the light emitted from all the pixels 2110p is made uniform, uneven luminance or chromaticity occurs in the first image IM1. That is, the quality of the first image IM1 is reduced. Therefore, in order not to reduce the quality of the first image IM1, it is necessary to take in light emitted from each pixel 2110p of the display device 2110 from the normal direction. As a result, the imaging optical system 2120 is enlarged.

[0102] In contrast, in the light source unit 11 of the present embodiment, the imaging optical system 120 has a substantially telecentric property on the side of the first image IM1, and the light emitted from the display device 110 has a substantially Lambertian distribution. Therefore, it is possible to improve the quality of the first image IM1 while miniaturizing the light source unit 11. Specifically, the display device 110 is an LED display having a plurality of LED elements 112, and the light emitted from each LED element 112 has a substantially Lambertian distribution. Therefore, the angular dependence of the luminance and chromaticity of the light emitted from each pixel 110p of the display device 110 is lower than the angular dependence of the luminance and chromaticity of the light emitted from each pixel 2110p of the display device 2110 in the reference example. In particular, the closer to the strict Lambertian distribution, that is, the approximate formula of the light distribution pattern, i.e., cos n The closer n of θ is to 1, the more uniform the luminance and chromaticity of light emitted from each pixel 110p of the display device 110 are regardless of the angle. Fig. 6A As shown, even if the imaging optical system 120 takes in light passing through the focal point F, that is, even if light is taken in from a direction other than the normal direction, it is possible to suppress unevenness in brightness and chromaticity of the first image IM1 and improve the quality of the first image IM1.

[0103] In addition, the imaging optical system 120 mainly forms the first image IM1 by the light passing through the focal point F, and therefore, the expansion of the optical path of the light incident on the imaging optical system 120 can be suppressed. Thus, the input element 121 can be miniaturized. In addition, the plurality of principal light rays L emitted from the output element 123 are substantially parallel to each other. The plurality of principal light rays L emitted from the output element 123 are substantially parallel to each other means that the range of light that contributes to imaging in the output element 123 is substantially the same as the size of the first image IM1. Therefore, the output element 123 of the imaging optical system 120 can also be miniaturized. As described above, a light source unit 11 that is compact and capable of forming a high-quality first image IM1 can be provided.

[0104] In addition, the image display system 10 of the present embodiment includes a light source unit 11, and a reflection unit 12 that is separated from the light source unit 11 and reflects light emitted from the imaging optical system 120. The first image IM1 is formed between the light source unit 11 and the reflection unit 12. In this case, light emitted from a certain point of the display device 110 is focused at the formation position of the first image IM1 after passing through the output element 123. On the other hand, when the first image IM1 is not formed between the light source unit 11 and the reflection unit 12, the light path of the light emitted from a certain point of the display device 110 gradually expands from the input element 121 toward the reflection unit 12. Therefore, in the present embodiment, the range of light emitted from a certain point of the display device 110 in the output element 123 can be reduced compared with the case where the first image IM1 is not formed. Therefore, the output element 123 can be miniaturized.

[0105] Furthermore, since the light source unit 11 of the present embodiment is small, when the light source unit 11 is mounted on the vehicle 13 and used as a head-up display, the light source unit 11 can be easily disposed in a limited space in the vehicle 13 .

[0106] In addition, the imaging optical system 120 of this embodiment has a curved portion 120a and a direction changing portion 120b. Thus, in the imaging optical system 120, by separately forming a portion having a function of making the principal rays L parallel to each other and a portion forming the first image IM1 at a desired position, the design of the imaging optical system 120 becomes easy.

[0107] In addition, a part of the optical path in the imaging optical system 120 extends in a direction intersecting the XY plane. Therefore, the imaging optical system 120 can be miniaturized in the direction along the XY plane. In addition, another part of the optical path in the imaging optical system 120 extends in a direction along the XY plane. Therefore, the imaging optical system 120 can be miniaturized in the Z direction.

[0108] <Example>

[0109] Next, light source units according to the embodiment and reference examples are described.

[0110] Fig. 7A It is a graph showing the light distribution pattern of light emitted from one light emitting area in Examples 1 and 11, the reference example, and the LCD.

[0111] Figure 7B It is a graph showing the uniformity of the brightness of the second image in Examples 1 to 12 and the reference example.

[0112] The image display systems of Examples 1 to 12 and the reference example include a light source unit and a reflection unit. The light source unit is set on the simulation software to include a plurality of light emitting regions arranged in a matrix and an imaging optical system. Each light emitting region corresponds to each pixel 110 p of the display device 110 in the above embodiment.

[0113] exist Fig. 7A In the figure, the horizontal axis is the angle relative to the optical axis of the luminous area, and the vertical axis is the luminance normalized by dividing the luminance at the angle by the luminance on the optical axis, indicating the relative value when the maximum value is set to 1. Fig. 7A As shown, the display device of Example 1 is set on the simulation software in such a way that the light emitted from each light emitting area has a light distribution pattern in which the luminous intensity in the direction forming an angle θ with respect to the optical axis is expressed as cosθ times the luminous intensity on the optical axis. That is, in Example 1, the light emitted from each light emitting area has a strict Lambertian light distribution.

[0114] In Examples 2 to 12, the light emitted from each light emitting region in the direction forming an angle θ with respect to the optical axis has a cosine of the light intensity on the optical axis. n The light distribution pattern represented by θ times is set on the simulation software. It should be noted that in Example 2, n=2, and n is set to increase one by one from Example 2 to Example 12.

[0115] In addition, the light distribution pattern of light emitted from the pixels of the LCD in one plane was investigated and the results showed that Fig. 7A The thin dashed line in the middle represents such a light distribution pattern. As mentioned above, this light distribution pattern can be approximated by the cosine of the light intensity on the optical axis. 20 Therefore, in the reference example, the luminous intensity in the direction having an angle θ with respect to the optical axis of each light-emitting region is calculated by cosine of the luminous intensity on the optical axis. 20 The method of expressing the light distribution pattern in θ-fold is set on the simulation software.

[0116] The imaging optical systems in Examples 1 to 12 and the reference example are all set to have telecentricity on the first image side.

[0117] Next, the brightness distribution of the second image formed when the brightness of all the light-emitting areas is kept constant is simulated for each of Examples 1 to 12 and the reference example. At this time, the second image is set to a rectangle with a long side of 111.2 mm and a short side of 27.8 mm. In addition, at this time, the plane forming the second image is divided into square areas with a side of 1 mm, and the brightness value of each area is simulated.

[0118] In addition, the uniformity of the brightness of the second image at this time is evaluated. Here, "uniformity of brightness" is a value expressing the ratio of the minimum brightness value to the maximum brightness value in the second image in percentage. The result is shown in Figure 7B It should be noted that Figure 7B In the figure, the horizontal axis represents the embodiments and the reference example, and the vertical axis represents the uniformity of brightness.

[0119] like Figure 7B As shown, the larger n is, the lower the uniformity of brightness is. This is because the larger n is, the lower the brightness is at the position away from the center in the second image. In particular, it is known that in Example 11, that is, n=11, the uniformity of brightness is 30%. Since it is easy for the viewer to distinguish the second image and the area where the second image is not formed, it is considered that the uniformity of the brightness of the second image only needs to be 30% or more.

[0120] Therefore, it can be seen that when the imaging optical system is configured to have a substantially telecentric property, in order to suppress the uneven brightness of the first image and the second image, it is preferable that the light emitted from the display device has a substantially Lambertian light distribution. Specifically, it can be seen that cos n The value n of θ is preferably 11 or less, and more preferably 1. It should be noted that, as described above, as n deviates from 1, the uniformity of the brightness of the second image IM2 decreases, but a predetermined brightness distribution can be set in advance for the display brightness of the display device 110 to compensate for the non-uniformity of the brightness. For example, when the brightness of the outer edge of the second image IM2 is likely to be lower than the brightness of the center due to the light emitted from each pixel 110p of the display device 110 passing through the imaging optical system 120, the display device 110 can be controlled in such a manner that the output of the LED element 112 of the pixel 110p on the outer edge side of the display device 110 is greater than the output of the LED element 112 of the pixel 110p on the center side.

[0121] <Second embodiment>

[0122] Next, a second embodiment will be described.

[0123] Figure 8 It is a top view showing the image display system according to this embodiment.

[0124] Fig. 9 It is an end view showing the image display system according to the present embodiment.

[0125] Fig.10 It is a schematic diagram showing the scene viewed from the viewer in the driver's seat.

[0126] like Figure 8 and Fig. 9 As shown, the automobile 1000 of the present embodiment includes a vehicle 13, a condition detection unit 16 fixed to the vehicle 13, and an image display system 20 fixed to the vehicle 13. The image display system 20 includes a light source unit 11, a drive unit 15, and a reflection unit 22. The image display system 20 of the present embodiment is different from the image display system 10 of the first embodiment in that the reflection mirror surface 322a of the reflection mirror 322 of the reflection unit 22 also serves as a reflection surface for the identifier 14 to recognize the second image IM2. That is, in the present embodiment, the reflection mirror 322 is a projection unit.

[0127] The configurations of the light source unit 11 and the drive unit 15 in the image display system 20 are the same as those in the first embodiment. The light source unit 11 is disposed on the top 13b of the vehicle 13. The drive unit 15 moves the light source unit 11 about the axis CR extending in the Z direction as a rotation axis, and controls the orientation of the light source unit 11.

[0128] The reflection unit 22 is arranged on the dashboard portion 13c of the vehicle 13. The reflection unit 22 has a reflection mirror 322. The reflection mirror surface 322a of the reflection mirror 322 is, for example, a concave surface. The reflection mirror surface 322a is arranged at a position and angle opposite to the eye movement range 14a of the identifier 14 when the identifier 14 is in the driver's seat of the vehicle 13. For example, the reflection mirror surface 322a faces a direction between the -X direction (rear) and the +Z direction (upward). The angle of the reflection mirror surface 322a can be finely adjusted according to the position of the eye movement range 14a of the identifier 14. In addition, as a reflection surface for the identifier 14 to recognize the second image IM2, the front windshield 13a or the combiner can also be used instead of the reflection mirror surface 322a arranged on the dashboard portion 13c.

[0129] Next, the operation of this embodiment will be described.

[0130] The principal light ray L emitted from the light source unit 11 travels in a direction between the +X direction (forward) and the -Z direction (downward), is reflected on the reflective mirror surface 322a of the reflective mirror 322 of the reflective unit 22, travels in a direction between the -X direction (backward) and the +Z direction (upward), and enters the eye movement range 14a of the identifier 14. The path of the principal light ray L from the light source unit 11 toward the reflective unit 12 is located on the inner side of the front windshield 13a of the vehicle 13 and is substantially along the front windshield 13a. The principal light ray L forms a first image IM1 at a position P between the light source unit 11 and the reflective unit 22. At this time, the driving unit 15 controls the direction of the light source unit 11 according to the status signal S based on the output signal S0 of the status detection unit 16, and selects the position where the first image IM1 is formed.

[0131] Therefore, if Figures 8 to 10 As shown, the identifier 14 can identify the second image IM2 as a virtual image on the inner side of the reflective mirror surface 322a of the instrument panel portion 13c. The second image IM2 is identified as being formed on the reflective mirror surface 322a, and having a virtual image at a distance of the reflective mirror surface 322a, for example, 3m away. Therefore, the identifier 14 can observe the second image IM2 without significantly moving the focal distance of the eyes from the state of observing the distant scenery through the front windshield 13a. In addition, the drive unit 15 controls the orientation of the light source unit 11 to select the position at which the first image IM1 is formed, thereby also selecting the position at which the second image IM2 is formed. Figure 8 and Fig.10 In the example shown, three positions PD, PE, and PF are selected. It should be noted that the reflector 322 may be a single reflector that includes all of the positions PD, PE, and PF, or may be divided for each position PD, PE, and PF. The curvature of the reflector surface 322a may be uniform or may be different for each position PD, PE, and PF.

[0132] Next, the effects of this embodiment will be described.

[0133] Similar to the first embodiment, the image display system 20 of this embodiment is divided into two units, namely, a unit including a light source unit 11 and a driving unit 15, and a reflecting unit 22, which are arranged at different positions in the vehicle 13. The image display system 20 requires a long optical path length in order to identify the second image IM2 in a manner that it is located several meters ahead, but by separately configuring the light source unit 11, the driving unit 15, and the reflecting unit 22, a part of the optical path length can be formed by using the internal space of the vehicle 13. As a result, it is not necessary to form the entire necessary optical path length inside the image display system 20, and the image display system 20 can be miniaturized.

[0134] In the image display system 20 of this embodiment, only the reflective mirror 322 is provided in the reflective unit 22. Thus, the structure of the reflective unit 22 can be simplified and the reflective unit 22 can be miniaturized. The structure, operation and effects of this embodiment other than the above are the same as those of the first embodiment.

[0135] It should be noted that the reflector 322 of the reflection unit 22 may also be composed of a semi-transparent reflector or a transparent plate. Even in this case, if the interior of the instrument panel portion 13c is darkened, it is possible to prevent the identifier 14 from observing the interior of the instrument panel portion 13c. Alternatively, the reflector surface 322a of the reflector 322 may be set to black to a degree that fully reflects the main light L emitted from the light source unit 11. Thus, it is possible to prevent the reduction in visibility caused by the reflection of the reflector surface 322a of the reflector 322 by external light. In addition, the reflector 322 may also be arranged continuously with the surface of the instrument panel portion 13c. Thus, it is not necessary to open a hole in the instrument panel portion 13c, and the design of the interior of the automobile 1000 is improved.

[0136] The reflectance of light of the reflector 3a22, or a semi-transparent reflector or a transparent plate (hereinafter referred to as "reflector 322, etc.") used instead of the reflector 322 is preferably 20% or less, more preferably 10% or less, and further preferably 5% or less. Thus, the reflection of the top 13b of the vehicle 13 or the sky into the reflector 322, etc. can be suppressed, so that the identifier 14 can clearly recognize the second image IM2. For example, the reflector 322, etc. can be realized by forming an anti-reflection film on the surface of the glass.

[0137] By using the reflective mirror surface 322 a disposed on the instrument panel portion 13 c as the reflective surface, the viewer 14 can reliably view the second image IM2 without being affected by the background of the reflective surface.

[0138] <Third Embodiment>

[0139] Next, a third embodiment will be described.

[0140] Fig.11 It is an end view showing the image display system according to the present embodiment.

[0141] Fig.12 Yes Fig.11 The display device and the reflective polarization element are shown in a partially enlarged cross-sectional view.

[0142] like Fig.11 and Fig.12 As shown, the image display system 70A of this embodiment is different from the image display system 10 of the first embodiment in that it includes a display device 710A instead of the display device 110 and further includes a reflective polarization element 740. The display device 710A of this embodiment is different from the display device 110 of the first embodiment in that the light emitting surface of the LED element 712 is substantially flat and further includes a protective layer 714, a wavelength conversion member 715, and a light scattering member 716A. The other structures of the display device 710A are the same as those of the display device 110 of the first embodiment. In addition, the image display system 70A of this embodiment includes a drive unit 15, similar to the image display system 10 of the first embodiment.

[0143] The protective layer 714 covers the plurality of LED elements 712 arranged in a matrix. The protective layer 714 can be made of a light-transmitting material such as a polymer material having a sulfur (S) substituent or a phosphorus (P) atom group, or a high-refractive-index nanocomposite material having inorganic nanoparticles of high refractive index introduced into a polymer matrix such as polyimide.

[0144] The wavelength conversion component 715 is disposed on the protective layer 714. The wavelength conversion component 715 includes one or more wavelength conversion materials such as ordinary phosphor materials, perovskite phosphor materials, or quantum dots (Quantum Dot: QD). The light emitted from each LED element 712 is incident on the wavelength conversion component 715. The wavelength conversion material contained in the wavelength conversion component 715 emits light of a peak wavelength different from the peak wavelength of light emission of each LED element 712 by the light emitted from each LED element 712. The light emitted by the wavelength conversion component 715 has a substantially Lambertian light distribution.

[0145] The light scattering component 716A includes, for example, a resin component having light transmittance, and light scattering particles or pores disposed in the resin component. As the resin component, for example, polycarbonate can be cited. As the light scattering particles, for example, materials having a refractive index difference with the resin component such as titanium oxide can be cited. It should be noted that the light scattering component 716A can also obtain a light scattering effect by roughening its surface to provide concavo-convexity.

[0146] As the reflective polarizing element 740, for example, a multi-layer thin film laminated polarizing plate having thin film layers with different polarization characteristics can be used. The reflective polarizing element 740 is disposed on the display device 710A. In the present embodiment, the reflective polarizing element 740 is disposed on the light scattering component 716A. Therefore, the light emitted from the LED element 712 and the wavelength conversion component 715 is incident on the reflective polarizing element 740. The reflective polarizing element 740 transmits the first polarized light 710p of the light emitted from the display device 710A, and reflects the second polarized light 710s toward the display device 710A. The vibration direction of the electric field of the second polarized light 710s is substantially orthogonal to the vibration direction of the electric field of the first polarized light 710p.

[0147] In this embodiment, the first polarized light 710p is P polarized light, and the second polarized light 710s is S polarized light. Here, "P polarized light" refers to light whose electric field vibration direction is substantially parallel to the XY plane. In addition, "S polarized light" refers to light whose electric field vibration direction is substantially perpendicular to the XY plane containing the incident light and the reflected light.

[0148] The identifier 14 driving the vehicle 13 sometimes wears polarized sunglasses 14b in order to reduce the glare of sunlight or the like reflected by puddles or the like in front of the vehicle 13 and transmitted through the front windshield 13a. In this case, the sunlight or the like reflected by the puddles or the like has a particularly reduced component of P polarized light when viewed from the front windshield 13a during reflection, and therefore, the polarized sunglasses 14b are designed to block most of the S polarized light. Therefore, when the identifier 14 wears the polarized sunglasses 14b, most of the S polarized light contained in the light emitted by the display device 710A is also blocked by the polarized sunglasses 14b, and the identifier 14 may have difficulty in identifying the second image IM2. It should be noted that the P polarized light and the S polarized light in this specification are physically defined by the presence of the above-mentioned reflective objects such as puddles.

[0149] In this embodiment, the reflective polarizing element 740 transmits the first polarized light 710p of the light emitted from the display device 710A and reflects the second polarized light 710s. Most of the first polarized light 710p transmitted through the reflective polarizing element 740 passes through the imaging optical system 120, the reflection unit 12, and the inner surface of the front windshield 13a, and is not blocked by the polarized sunglasses 14b, but enters the eye movement range 14a. It should be noted that the incident angle of the first polarized light 710p when incident on the inner surface of the front windshield 13a is set to be an angle different from the Brewster angle.

[0150] Specifically, if Fig.12As shown, the light emitted from the LED element 712 is irradiated to the wavelength conversion component 715. As a result, the wavelength conversion component 715 is excited to emit light having a peak wavelength longer than the peak wavelength of the light emitted from the LED element 712. In the present embodiment, the light emitted from the display device 710A includes the light emitted from the LED element 712 and the light emitted from the wavelength conversion component 715. Hereinafter, among the light emitted from the display device 710A, the light emitted from the LED element 712 is referred to as "short wavelength light", and the light emitted from the wavelength conversion component 715 is referred to as "long wavelength light". However, most of the light emitted from the LED element 712 may also be absorbed by the wavelength conversion component 715.

[0151] Most of the first polarized light 710p included in these short-wavelength light and long-wavelength light is transmitted through the reflective polarization element 740 and emitted from the imaging optical system 120. In addition, most of the second polarized light 710s included in these short-wavelength light and long-wavelength light is reflected by the reflective polarization element 740. A part of the second polarized light 710s reflected by the reflective polarization element 740 is scattered and reflected in the components of the display device 710A such as the light scattering component 716A and the wavelength conversion component 715. Through scattered reflection, a part of the second polarized light 710s is converted into the first polarized light 710p. A part of the first polarized light 710p converted from the second polarized light 710s is transmitted through the reflective polarization element 740 and emitted from the light source unit 71A. Therefore, it is possible to increase the ratio of the first polarized light 710p included in the light emitted from the light source unit 71A while increasing the brightness of the first image IM1. As the brightness of the first image IM1 is increased, the brightness of the second image IM2 is also increased. As a result, the recognizer 14 can easily recognize the second image IM2.

[0152] In addition, a portion of the short-wavelength light contained in the second polarized light 710s may also be reflected by the reflective polarizing element 740 and then incident on the wavelength conversion component 715. In this case, it is expected that the wavelength conversion component 715 absorbs the short-wavelength light of the second polarized light 710s and re-radiates the long-wavelength light. These scattered reflected light and radiated light both have a roughly Lambertian light distribution. In addition, the reflective polarizing element 740 itself may also scatter and reflect the second polarized light 710s. In this case, by scattering and reflecting, a portion of the second polarized light 710s is also converted into the first polarized light 710p.

[0153] In the present embodiment, one reflective polarizing element 740 covers all pixels of the display device 710A. However, the light source unit may also include a plurality of reflective polarizing elements, and each reflective polarizing element may be disposed on each pixel. In addition, the structure of the display device used in combination with the reflective polarizing element is not limited to the above. For example, by using the scattering reflection effect of light possessed by the wavelength conversion component, the display device may also be configured to have a structure where no light scattering component is provided. In addition, by using the scattering reflection effect of the light scattering component, the display device may also be configured to have a structure where no wavelength conversion component is provided. In addition, as in the first embodiment, by using the scattering reflection effect of light brought about by a plurality of recesses or a plurality of protrusions disposed on the light emitting surface of the LED element, the display device may also be configured to have a structure where neither a wavelength conversion component nor a light scattering component is provided.

[0154] Next, the effects of this embodiment will be described.

[0155] The light source unit 71A of this embodiment further includes a reflective polarization element 740, which is disposed on the display device 710A and transmits the first polarization light 710p in the light emitted from the display device 710A and reflects the second polarization light 710s in the light emitted from the display device 710A. Therefore, the ratio of the first polarization light 710p contained in the light emitted from the light source unit 71A can be increased, and the brightness of the first image IM1 can be increased.

[0156] In addition, the light emitted from the reflective polarizing element 740 also has a roughly Lambertian light distribution. Therefore, in this embodiment, a light source unit 71A that is small and can form a high-quality first image IM1 can also be provided. It should be noted that because the plurality of LED elements 712 are discretely mounted on the substrate 111, the first image IM1 sometimes produces a granular feel. The wavelength conversion component 715 has an effect of alleviating the granular feel. Moreover, the light scattering component 716A can further enhance the effect of alleviating the granular feel. The structure, operation and effect of this embodiment other than the above are the same as those of the first embodiment.

[0157] <Modification of the third embodiment>

[0158] Next, a modification of the third embodiment will be described.

[0159] Fig.13 This is an end view showing the display device of this variation.

[0160] Fig.14 It is a perspective view showing a reflective polarization element according to this modification.

[0161] like Fig.13As shown, the display device 710B of this modification is different from the display device 710A of the third embodiment in that a reflective polarization element 740B is provided instead of the reflective polarization element 740. The reflective polarization element 740B is disposed on the LED element 712 and in contact with the LED element 712.

[0162] like Fig.14 As shown, the reflective polarizing element 740B is a wire grid polarizer. In the reflective polarizing element 740B, a plurality of metal wires 740d are arranged in parallel with each other at equal intervals on a transparent resin film 740c. Thus, the reflective polarizing element 740B transmits the first polarized light 710p of the light emitted from the LED element 712, and reflects the second polarized light 710s so that it returns to the LED element 712. The structure, operation and effect of this modification other than the above are the same as those of the third embodiment.

[0163] <Fourth embodiment>

[0164] Next, a fourth embodiment will be described.

[0165] Fig.15 It is a side view showing the light source unit according to the present embodiment.

[0166] like Fig.15 As shown, the image display system 70B of this embodiment is different from the image display system 10 of the first embodiment in that the light source unit 71B includes a display device 710A having the same structure as the third embodiment instead of the display device 110, and further includes a reflective polarizing element 750 and a light shielding member 760. Fig.15 In FIG. 7 , only the light shielding member 760 is shown in cross section.

[0167] The reflective polarization element 750 can be, for example, a wire grid type reflective polarization element using a plurality of metal nanowires. The reflective polarization element 750 is disposed in a portion of the optical path from the display device 710A to the reflective unit 12 where a plurality of principal light rays L are substantially parallel to each other. In the present embodiment, a plurality of principal light rays L are substantially parallel to each other in the optical path from the intermediate element 122 to the reflective unit 12, and the reflective polarization element 750 is disposed between the intermediate element 122 and the output element 123.

[0168] The reflective polarization element 750 transmits the first polarized light 710p as P polarized light and reflects the second polarized light 710s as S polarized light to return to the display device 710A. Specifically, the display device 710A emits light 710a including the first polarized light 710p and the second polarized light 710s. The light 710a passes through the input element 121 and the intermediate element 122 and then enters the reflective polarization element 750.

[0169] The reflective polarization element 750 transmits most of the first polarized light 710 p included in the light 710 a . Most of the first polarized light 710 p that has transmitted through the reflective polarization element 750 passes through the output element 123 and is then emitted from the reflection unit 12 .

[0170] The reflective polarizing element 750 reflects most of the second polarized light 710s contained in the light 710a in a manner that returns to the optical path from the display device 710A to the reflective polarizing element 750. Specifically, the reflective polarizing element 750 is in the shape of a flat plate. The reflective polarizing element 750 is arranged to be substantially orthogonal to the principal light beam L. The reflective polarizing element 750 performs regular reflection on most of the second polarized light 710s. Therefore, most of the second polarized light 710s reflected by the reflective polarizing element 750 returns to the display device 710A after passing through the intermediate element 122 and the input element 121 in sequence.

[0171] A portion of the second polarized light 710s that returns to the display device 710A is scattered and reflected by components of the display device 710A such as the light scattering component 716A and the wavelength conversion component 715. By scattered reflection, a portion of the second polarized light 710s is converted into the first polarized light 710p. A portion of the first polarized light 710p converted from the second polarized light 710s passes through the input element 121 and the intermediate element 122, and then transmits the reflective polarization element 750. Most of the first polarized light 710p that has transmitted through the reflective polarization element 750 passes through the output element 123 and then is emitted from the reflection unit 12. Therefore, it is possible to increase the ratio of the first polarized light 710p contained in the light emitted from the image display system 70B, and at the same time, increase the brightness of the second image IM2. As a result, the recognizer 14 can easily recognize the second image IM2.

[0172] In addition, similarly to the eleventh embodiment, a portion of the short-wavelength light included in the second polarized light 710s returned to the display device 710A may be irradiated to the wavelength conversion member 715. In this case, similarly to the eleventh embodiment, the wavelength conversion member 715 can be expected to absorb the short-wavelength light of the second polarized light 710s and re-reflect the long-wavelength light.

[0173] The light shielding member 760 is disposed between the display device 710A and the input element 121 of the imaging optical system 120. The shape of the light shielding member 760 is, for example, a flat plate substantially parallel to the XY plane. The light shielding member 760 is provided with an opening 761 that penetrates the light shielding member 760 in the Z direction. The focal point F of the imaging optical system 120 is located in the opening 761.

[0174] Among the light emitted from the display device 710A, the light that passes through the focal point F and its vicinity enters the input element 121 through the opening 761 of the light shielding member 760, and most of the other light is blocked by the light shielding member 760. In addition, among the second polarized light 710s reflected by the reflective polarizing element 750, the light that follows the optical path, that is, the light that passes through the focal point F and its vicinity passes through the opening 761 of the light shielding member 760 and returns to the display device 710A. On the other hand, among the second polarized light 710s reflected by the reflective polarizing element 750, the light that does not follow the optical path and goes toward the display device 710A is blocked by the light shielding member 760.

[0175] Next, the effects of this embodiment will be described.

[0176] The image display system 70B of this embodiment further includes a reflective polarization element 750. The reflective polarization element 750 is disposed in a portion of the optical path from the display device 710A to the reflection unit 12, where a plurality of principal light rays L emitted from different positions in the display device 710A and passing through the first image IM1 are substantially parallel to each other, and transmits the first polarized light 710p in the light emitted from the display device 710A, and reflects the second polarized light 710s in the light emitted from the display device 710A and returns it to the display device 710A. Therefore, the ratio of the first polarized light 710p contained in the light emitted from the image display system 70B can be increased, and the brightness of the second image IM2 can be increased.

[0177] In addition, a light shielding member 760 is provided between the display device 710A and the input element 121. The light shielding member 760 is provided with an opening 761 through which the second polarized light 710s that returns to the display device 710A along the optical path passes. Therefore, the light along the optical path of the second polarized light 710s reflected by the reflective polarizing element 750 is allowed to return to the display device 710A, and at the same time, the stray light that does not follow the optical path of the second polarized light 710s reflected by the reflective polarizing element 750 can be suppressed from heading toward the display device 710A. Thus, the quality of the first image IM1 and the second image IM2 can be improved. In addition, by using the light shielding member 760, the stray light that does not follow the optical path of the light emitted from the display device 710A can be suppressed from being reflected by the reflective polarizing element 750 and the optical elements of the imaging optical system 120, heading toward the display device 710A, and being re-excited or scattered and reflected at an unexpected place.

[0178] It should be noted that the image display system 70B may not be provided with the light shielding member 760. In addition, the reflective polarizing element 740 described in the third embodiment may be provided on the display device 710A of the image display system 70B. In this case, the reflective polarizing element 750 can be used to reflect the second polarized light 710s that is not reflected by the reflective polarizing element 740 on the display device 710A. Therefore, the brightness of the second image IM2 can be increased while increasing the ratio of the first polarized light 710p contained in the light emitted from the image display system 70B. The structure, operation and effect of this embodiment other than the above are the same as those of the third embodiment.

[0179] <Modification of the Fourth Embodiment>

[0180] Next, a modification of the fourth embodiment will be described.

[0181] Fig.16 It is a side view showing the light source unit according to this modification.

[0182] exist Fig.16 In FIG. 7 , only the light shielding component 760 is shown in cross section.

[0183] like Fig.16 As shown, in this modified example, the reflective polarization element 750 is disposed between the output element 123 and the reflection unit 12. Fig.16 , the reflective polarization element 750 is disposed between the output element 123 and the first image IM1, but the reflective polarization element 750 may be disposed between the first image IM1 and the reflection unit 12. The structure, operation, and effects of this modification other than those described above are the same as those of the fourth embodiment.

[0184] The above-mentioned embodiments and their variations are examples of specific implementations of the present invention, and the present invention is not limited to these embodiments and variations. For example, in the above-mentioned embodiments and variations, the addition, deletion or modification of some components or processes is also included in the present invention. In addition, the above-mentioned embodiments and variations can be combined with each other and implemented.

[0185] The embodiments include the following aspects.

[0186] (Note 1)

[0187] An image display system comprising:

[0188] A light source unit having: a display device capable of displaying an image; an imaging optical system for projecting a first image corresponding to the image onto a projection unit so that an image that can be recognized by a viewer appears to be displayed on the opposite side of the projection unit from the viewer;

[0189] The driving unit changes the position of the first image by controlling the position and / or orientation of the light source unit based on a status signal input from the outside.

[0190] (Note 2)

[0191] An image display system as described in Note 1, wherein:

[0192] The above-mentioned image display system is installed in a vehicle.

[0193] The driving unit controls the direction of the light source unit using an axis extending in the up-down direction of the vehicle as a rotation axis.

[0194] (Note 3)

[0195] An image display system as described in Note 2, wherein:

[0196] The above-mentioned status signal indicates the traveling direction of the above-mentioned vehicle,

[0197] The driving unit sets the direction in which the light source unit projects the first image to a direction corresponding to the traveling direction.

[0198] (Note 4)

[0199] An image display system as described in Note 2, wherein:

[0200] The condition signal indicates the sight direction of the driver of the vehicle.

[0201] The driving unit sets the direction in which the light source unit projects the first image to a direction corresponding to the line of sight direction.

[0202] (Note 5)

[0203] An image display system as described in Note 2, wherein:

[0204] the condition signal indicates a direction of an object external to the vehicle,

[0205] The driving unit sets a direction in which the light source unit projects the first image to a direction corresponding to a direction toward the object.

[0206] (Note 6)

[0207] An image display system as described in any one of Notes 1 to 5, wherein:

[0208] The projection unit is a reflecting mirror or a semi-transmitting reflecting mirror.

[0209] (Note 7)

[0210] An image display system as described in any one of Notes 2 to 5, wherein:

[0211] The projection part is the front windshield of the vehicle.

[0212] (Note 8)

[0213] An image display system as described in any one of Notes 1 to 7, wherein:

[0214] The imaging optical system has:

[0215] an input element into which light emitted from the display device is incident;

[0216] an output element into which the light passing through the input element is incident,

[0217] The light emitted from the output element forms the first image.

[0218] The imaging optical system has a substantially telecentric property on the first image side.

[0219] The light emitted from the display device has a substantially Lambertian light distribution.

[0220] (Note 9)

[0221] An image display system as described in Note 8, wherein:

[0222] The light emitted from the display device has a luminous intensity in a direction which forms an angle θ with respect to the optical axis of the light emitted from the display device and is equal to the cosine of the luminous intensity on the optical axis. n The light distribution pattern is similar to θ times.

[0223] The above n is a value greater than 0.

[0224] (Note 10)

[0225] An image display system as described in Note 9, wherein:

[0226] The above n is 11 or less.

[0227] (Note 11)

[0228] An image display system as described in any one of Notes 1 to 10, wherein:

[0229] The display device is an LED display having a plurality of LED elements.

[0230] (Note 12)

[0231] An image display system as described in Note 11, wherein:

[0232] The light emitted from the LED element has a substantially Lambertian light distribution.

[0233] (Note 13)

[0234] An image display system as described in Note 11 or 12, wherein:

[0235] The display device further includes a wavelength conversion member that is disposed on the LED element and on which light emitted from the LED element is incident.

[0236] (Note 14)

[0237] An image display system as described in any one of Notes 1 to 13, wherein:

[0238] The imaging optical system comprises: a bending portion including the input element; a direction changing portion including the output element;

[0239] The bending portion bends the plurality of principal rays so that the plurality of principal rays emitted from different positions in the display device and crossing each other before entering the input element to reach the first image are substantially parallel to each other in front of and behind the first image.

[0240] The direction changing unit changes the traveling directions of the plurality of principal rays so that the plurality of principal rays passing through the curved portion are directed toward a formation position of the first image.

[0241] (Note 15)

[0242] An image display system as described in any one of Notes 1 to 14, wherein:

[0243] The light source unit further includes a shading component, which is disposed between the display device and the imaging optical system, has an opening for allowing a portion of light from the display device toward the imaging optical system to pass through, and blocks another portion of light from the display device toward the imaging optical system.

[0244] (Note 16)

[0245] An image display system as described in any one of Notes 1 to 15, wherein:

[0246] A reflecting unit is further provided, the reflecting unit being separated from the light source unit and reflecting the light emitted from the imaging optical system.

[0247] The first image is formed between the light source unit and the reflection unit.

[0248] (Note 17)

[0249] An image display system as described in Note 16, wherein:

[0250] It also includes a reflective polarization element, which is arranged on the optical path from the above-mentioned display device to the above-mentioned reflection unit, transmits the first polarization light in the light emitted from the above-mentioned display device, and reflects the second polarization light in the light emitted from the above-mentioned display device to return it to the above-mentioned display device.

[0251] (Note 18)

[0252] An image display system as described in Note 17, wherein:

[0253] The reflective polarizing element is disposed in a portion of the optical path from the display device to the reflecting unit where a plurality of principal light rays emitted from different positions in the display device and passing through the first image are substantially parallel to each other.

[0254] (Note 19)

[0255] A car comprising:

[0256] the above-mentioned vehicle;

[0257] A condition detection unit that detects the internal or external condition of the vehicle;

[0258] An image display system as described in any one of Notes 2 to 18, which is fixed to the above-mentioned vehicle.

[0259] Industrial Applicability

[0260] The present invention can be used, for example, in a head-up display.

[0261] Description of Reference Numerals

[0262] 10, 20, 70A, 70B: Image display system

[0263] 11, 71A, 71B: Light source unit

[0264] 12: Reflection unit

[0265] 13: Vehicles

[0266] 13a: Front windshield

[0267] 13b: Top

[0268] 13c: Instrument panel

[0269] 13h1, 13h2: Through hole

[0270] 13s1, 13s2: wall

[0271] 14: Identifier

[0272] 14a: Eye Movement Range

[0273] 14b: Polarized Sunglasses

[0274] 15: Drive unit

[0275] 16: Status Detection Department

[0276] 20: Image display system

[0277] 22: Reflection unit

[0278] 110: Display device

[0279] 110p: Pixel

[0280] 111: Substrate

[0281] 112: LED components

[0282] 112a: Semiconductor stack

[0283] 112b: Anode electrode

[0284] 112c: cathode electrode

[0285] 112p1: p-type semiconductor layer

[0286] 112p2: Active layer

[0287] 112p3: n-type semiconductor layer

[0288] 112s: light exit surface

[0289] 112t: concave part

[0290] 118a: Wiring

[0291] 120, 2120: Imaging optical system

[0292] 120a: Bend

[0293] 120b: Direction change unit

[0294] 121: Input element

[0295] 121a: Reflective mirror

[0296] 122: Intermediate components

[0297] 122a: Reflective mirror

[0298] 123: Output element

[0299] 123a: Reflective mirror

[0300] 131: Reflector

[0301] 131a: Reflective mirror

[0302] 322: Reflector

[0303] 322a: Reflective mirror

[0304] 710, 710A, 710B: display device

[0305] 710a: light

[0306] 712: LED components

[0307] 712p3: n-type semiconductor layer

[0308] 714: Protective layer

[0309] 715: Wavelength conversion components

[0310] 716A: Light scattering components

[0311] 740: Reflective polarizing element

[0312] 740B: Reflective polarizing element

[0313] 740c: Resin film

[0314] 740d: Metal wire

[0315] 750: Reflective polarizing element

[0316] 760: Light shielding parts

[0317] 761: Opening

[0318] 1000: Cars

[0319] 2011: Light source unit

[0320] 2110: Display device

[0321] 2110p: Pixel

[0322] 2110s: light exit surface

[0323] C: Optical axis

[0324] CR: Axis

[0325] F: Focus

[0326] IM1: First Image

[0327] IM2: Second Image

[0328] L: Main ray

[0329] P: Formation position

[0330] PA, PB, PC, PD, PE, PF: Position

[0331] S: Status signal

[0332] S0: Output signal

[0333] a1, a2: points

[0334] θ: Angle

Claims

1. An image display system, characterized in that: have: A light source unit having: a display device capable of displaying an image; an imaging optical system for projecting a first image corresponding to the image onto a projection unit so that an image that can be recognized by a viewer appears to be displayed on the opposite side of the projection unit from the viewer; A driving unit changes the position of the first image by controlling the position and / or orientation of the light source unit based on a status signal input from the outside.

2. The image display system according to claim 1, wherein: The image display system is mounted on a vehicle. The driving unit controls the orientation of the light source unit with an axis extending in the vertical direction of the vehicle as a rotation axis.

3. The image display system according to claim 2, wherein: The status signal indicates a traveling direction of the vehicle, The driving unit sets the direction in which the light source unit projects the first image to a direction corresponding to the traveling direction.

4. The image display system according to claim 2, wherein: The condition signal indicates the sight direction of the driver of the vehicle, The driving unit sets the direction in which the light source unit projects the first image to a direction corresponding to the line of sight direction.

5. The image display system according to claim 2, wherein: the condition signal indicates a direction of an object external to the vehicle, The driving unit sets the direction in which the light source unit projects the first image to a direction corresponding to a direction toward the object.

6. The image display system according to any one of claims 1 to 5, wherein: The projection part is a reflecting mirror or a semi-transmitting reflecting mirror.

7. The image display system according to any one of claims 2 to 5. The projection part is the front windshield of the vehicle.

8. The image display system according to any one of claims 1 to 7. The imaging optical system comprises: an input element into which light emitted from the display device is incident; an output element into which the light passing through the input element is incident, The light emitted from the output element forms the first image, The imaging optical system has a substantially telecentric property on the first image side, Light emitted from the display device has a substantially Lambertian light distribution.

9. The image display system according to claim 8, wherein: The light emitted from the display device has a luminance in a direction at an angle θ relative to the optical axis of the light emitted from the display device and a value corresponding to the cosine of the luminance on the optical axis. n The light distribution pattern is similar to θ times. The n is a value greater than 0.

10. The image display system according to claim 9, wherein: The n is 11 or less.

11. The image display system according to any one of claims 1 to 10, wherein: The display device is an LED display having a plurality of LED elements.

12. The image display system according to claim 11, wherein: The light emitted from the LED element has a substantially Lambertian light distribution.

13. The image display system according to claim 11 or 12, wherein: The display device further includes a wavelength conversion member that is disposed on the LED element and into which light emitted from the LED element is incident.

14. The image display system according to any one of claims 1 to 13, wherein: The imaging optical system comprises: a bending portion including the input element; a direction changing portion including the output element, The bending portion bends the plurality of principal rays so that the plurality of principal rays emitted from different positions in the display device and crossing each other before entering the input element to reach the first image are substantially parallel to each other in front of and behind the first image. The direction changing unit changes the traveling directions of the plurality of principal rays so that the plurality of principal rays passing through the curved portion are directed toward a formation position of the first image.

15. The image display system according to any one of claims 1 to 14, wherein: The light source unit also has a shading component, which is arranged between the display device and the imaging optical system, has an opening for passing a part of the light from the display device toward the imaging optical system, and blocks another part of the light from the display device toward the imaging optical system.

16. The image display system according to any one of claims 1 to 15, wherein: A reflecting unit is further provided, the reflecting unit being separated from the light source unit and reflecting the light emitted from the imaging optical system. The first image is formed between the light source unit and the reflection unit.

17. The image display system according to claim 16, wherein: It also includes a reflective polarization element, which is arranged on the optical path from the display device to the reflection unit, transmits the first polarization light in the light emitted from the display device, and reflects the second polarization light in the light emitted from the display device to return it to the display device.

18. The image display system according to claim 17, wherein: The reflective polarizing element is disposed in a portion of the optical path from the display device to the reflecting unit where a plurality of principal light rays emitted from different positions in the display device and passing through the first image are substantially parallel to each other.

19. A car, characterized in that: have: the vehicle; a condition detection unit that detects a condition inside or outside the vehicle; The image display system according to any one of claims 2 to 18, which is fixed to the vehicle.

Images