Light source unit, image display device, and automobile

Abstract

A light source unit is provided with: a display device which has a plurality of pixels and is capable of displaying an image; a color changing sheet on which light emitted from the display device is incident; an imaging optical system; and a driving unit that changes a positional relationship between the display device and the color changing sheet. The imaging optical system forms a first image corresponding to the image. The color changing sheet has: a first region in which light is incident from the pixels and light of a first color is emitted; and a second region in which light is incident from the pixel and light of a second color is emitted. The driving unit changes a positional relationship between the display device and the color changing sheet between a first positional relationship in which light emitted from one of the pixels is incident on the first region and a second positional relationship in which light emitted from the one of the pixels is incident on the second region.

Description

Technical Field

[0001] The present embodiment relates to a light source unit, an image display device, and a car. Background Art

[0002] Patent document 1 discloses a technology that sequentially reflects light emitted from a display device capable of displaying an image through a plurality of mirrors, and further reflects the light reflected by the last mirror toward a user through a reflective component such as a windshield, so that the user can visually confirm a virtual image corresponding to the image displayed by the display device. However, in the technology disclosed in patent document 1, when colorizing an image, pixels corresponding to each color are required, so there is a problem of enlarging the display device.

[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 embodiments of the present invention is to provide a small light source unit, an image display device, and a car capable of displaying color images.

[0008] Technical solutions for solving technical problems

[0009] A light source unit according to an embodiment of the present invention includes: a display device having a plurality of pixels and capable of displaying an image; a color-changing sheet into which light emitted from the display device is incident; an imaging optical system; and a driving unit that changes the positional relationship between the display device and the color-changing sheet. The imaging optical system includes an input element into which light emitted from the color-changing sheet is incident and an output element into which light passing through the input element is incident, and light emitted from the output element forms a first image corresponding to the image. The color-changing sheet includes: a first region into which light is incident from the pixel and light of a first color is emitted; and a second region into which light of a second color different from the first color is incident from the pixel and light of a second color is emitted. The driving unit changes the positional relationship between the display device and the color-changing sheet between a first positional relationship in which light emitted from one pixel is incident on the first region and a second positional relationship in which light emitted from the one pixel is incident on the second region. The imaging optical system has a substantially telecentric property on the first image side, and light emitted from the display device has a substantially Lambertian light distribution.

[0010] The image display device according to the embodiment of the present invention comprises: the light source unit; and a reflection unit 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.

[0011] Effects of the Invention

[0012] According to the present embodiment, a small light source unit, an image display device, and a car capable of displaying color images can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is an end view showing the image display device according to the first embodiment.

[0014] Figure 2A It is a plan view of a display device showing the light source unit according to the first embodiment.

[0015] Figure 2B It is a plan view showing the color change sheet of the light source unit according to the first embodiment.

[0016] Figure 2C This is an end view showing a display device, a color change sheet, and a drive unit of the light source unit according to the first embodiment.

[0017] Figure 3 This is an end view of the display device showing the image display device according to the first embodiment.

[0018] Figure 4 This is an end view showing the change in the positional relationship between the pixels of the display device and the region of the color change sheet.

[0019] Figure 5A This is a plan view showing a change in the positional relationship between pixels of the display device and regions of the color change sheet in the first embodiment.

[0020] Figure 5B This is a plan view showing a change in the positional relationship between pixels of the display device and regions of the color change sheet in the first embodiment.

[0021] Figure 5C This is a plan view showing a change in the positional relationship between pixels of the display device and regions of the color change sheet in the first embodiment.

[0022] Figure 6 This is a schematic diagram showing a scene viewed by a visual checker in a driver's seat in the first embodiment.

[0023] Fig. 7A It is a schematic diagram showing the principle of the light source unit according to the first embodiment.

[0024] Figure 7B It is a schematic diagram showing the principle of the light source unit of the reference example.

[0025] Fig. 8A This is a graph showing the light distribution pattern of light emitted from one light emitting area in Examples 1 and 11 and the reference example.

[0026] Figure 8B This is a graph showing the uniformity of brightness of the second image in Examples 1 to 12 and the reference example.

[0027] Fig.9A It is a plan view showing a color change sheet of a light source unit according to a first modification of the first embodiment.

[0028] Fig. 9B It is a plan view showing a change in the positional relationship between pixels of a display device and a region of a color change sheet in a first modification example of the first embodiment.

[0029] Fig. 9C It is a plan view showing a change in the positional relationship between pixels of a display device and a region of a color change sheet in a first modification example of the first embodiment.

[0030] Fig.10 It is a plan view showing a color change sheet of a light source unit according to a second modification of the first embodiment.

[0031] Fig.11 It is an end view of a display device showing an image display device according to a second embodiment.

[0032] Fig.12 It is a plan view showing a color change sheet of a light source unit according to the second embodiment.

[0033] Fig.13 It is a plan view showing a color change sheet of a light source unit according to a first modified example of the second embodiment.

[0034] Fig.14 It is a plan view showing a color change sheet of a light source unit according to a second modification of the second embodiment.

[0035] Fig.15 It is a plan view showing a color change sheet of a light source unit according to a third embodiment.

[0036] Fig.16 It is a plan view showing a color change sheet of a light source unit according to a modification of the third embodiment.

[0037] Fig.17 This is a diagram showing the relationship between the color of light emitted from a pixel of a display device and the color change sheet.

[0038] Fig.18 It is a plan view showing a color change sheet of a light source unit according to a fourth embodiment.

[0039] Fig.19 It is a plan view showing a color change sheet of a light source unit according to a fifth embodiment.

[0040] Fig. 20 It is a plan view showing a color change sheet of a light source unit according to a sixth embodiment.

[0041] Fig.21 It is an end view showing an image display device according to a seventh embodiment.

[0042] Fig. 22 This is a schematic diagram showing a scene viewed by a visual checker in a driver's seat in the seventh embodiment.

[0043] Fig.23 It is an end view showing an image display device according to an eighth embodiment.

[0044] Fig.24 It is enlarged to show Fig.23 A cross-sectional view of a portion of a display device and a reflective polarizing element is shown.

[0045] Fig.25 It is a side view showing a light source unit according to a ninth embodiment.

[0046] Fig.26 It is a side view showing a light source unit according to a modification of the ninth embodiment. DETAILED DESCRIPTION

[0047] Hereinafter, various embodiments and their variations will be described with reference to the accompanying drawings. It should be noted that the accompanying drawings are schematic or conceptual, and appropriately emphasize or simplify. For example, the relationship between the thickness and width of each part, the ratio of the size between the parts, etc. are not necessarily the same as the actual situation. In addition, even when representing the same part, different sizes and ratios will be shown depending on the different drawings. Moreover, in this specification and each figure, the same figure mark is marked for the same elements as those in the description of the existing figures, and the detailed description is appropriately omitted.

[0048] <First Embodiment>

[0049] First, the first embodiment will be described.

[0050] Figure 1 It is an end view showing the image display device of this embodiment.

[0051] Figure 2A It is a plan view of a display device showing a light source unit according to the present embodiment.

[0052] Figure 2B It is a plan view showing the color change sheet of the light source unit according to the present embodiment.

[0053] Figure 2C It is an end view showing a display device, a color changing sheet, and a driving unit of the light source unit of the present embodiment.

[0054] like Figure 1 As shown, the image display device 10 of this embodiment includes: a light source unit 11 and a reflection unit 12. The light source unit 11 includes: a display device 110, an imaging optical system 120, a color change sheet 130, and a driving unit 140. The display device 110 has a plurality of pixels and can display an image. The light emitted from the display device 110 is incident on the color change sheet 130. The light emitted from the color change sheet 130 is incident on the imaging optical system 120 to form a first image IM1 corresponding to the image displayed by the display device 110. The first image IM1 is a real image and an intermediate image. The driving unit 140 changes the positional relationship between the display device 110 and the color change sheet 130. The reflection unit 12 is separated from the light source unit 11 and reflects the light emitted from the imaging optical system 120.

[0055] The image display device 10 is mounted on, for example, a car 1000 to form a HUD (Head Up Display). The car 1000 includes a vehicle 13 and the image display device 10 fixed to the vehicle 13. The visual checker 14 is a passenger of the car 1000, such as a driver.

[0056] The display device 110 of the light source unit 11 displays an image that is desired to be visually confirmed by the visual confirmer 14 through the HUD. The color change sheet 130 changes the color of the image displayed by the display device 110 for each pixel. This mechanism will be described later. The imaging optical system 120 outputs the light emitted from the color change sheet 130 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.

[0057] The front windshield 13a reflects the light reaching from the reflection unit 12 on its inner surface, and makes it incident on the visual field 14a of the visual confirmer 14. As a result, the visual confirmer 14 can visually confirm the second image IM2 corresponding to the image displayed by the display device 110 on the opposite side of the front windshield 13a. The second image IM2 is a virtual image larger than the first image IM1. The "visual field" refers to the range in the space in front of the visual confirmer where the virtual image can be visually confirmed.

[0058] In the following, for ease of understanding, the configuration and structure of each part are described using the XYZ orthogonal coordinate system. In the present embodiment, the front-to-back direction of the vehicle 13 is referred to as the "X direction", the length direction of the vehicle 13 is referred to as the "Y direction", and the up-down direction of the vehicle 13 is referred to 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 referred to as the "+X direction", and its opposite direction (rear) is also referred to as the "-X direction". In addition, the direction of the arrow in the Y direction (left) is referred to as the "+Y direction", and its opposite direction (right) is also referred to as the "-Y direction". In addition, the direction of the arrow in the Z direction (upward) is referred to as the "+Z direction", and its opposite direction (downward) is also referred to as the "-Z direction".

[0059] In addition, Figure 1 , the position where the first image IM1 is formed is indicated by a circular mark. 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 exit position of the principal light ray L reaching each mark of the first image IM1 in the display device 110 is indicated by a quadrilateral mark. In this way, in order to facilitate understanding of the description, the exit position of each principal light ray L on the display device 110 is indicated by a mark different from the imaging position of the first image IM1 and the imaging position of the second image IM2, but the image displayed on the display device 110 has a roughly similar relationship with the first image IM1 and the second image IM2.

[0060] like Figure 2A As shown, in the display device 110, a plurality of pixels 110p are arranged in rows and columns along a first direction and a second direction. The second direction intersects with the first direction, for example, is orthogonal. For example, the first direction is the horizontal direction of the image, and the second direction is the vertical direction of the image. In this embodiment, the first direction is taken as the X direction, and the second direction is taken as the Y direction. The color of light emitted from each pixel 110p is the same, which is white in this embodiment. The light emitted from the display device 110 has a substantially Lambertian distribution. The specific structure of the display device 110 and the Lambertian distribution will be described later.

[0061] like Figure 2B As shown, in the color change sheet 130, a plurality of regions 130p are arranged in rows and columns along the first direction and the second direction. The shape and size of each region 130p are substantially equal to the shape and size of each pixel 110p of the display device 110, and the arrangement period of the regions 130p in the first direction and the second direction is substantially equal to the arrangement period of the pixels 110p. Therefore, the pixels 110p of the display device 110 and the regions 130p of the color change sheet 130 correspond one to one, and all or most of the light emitted from one pixel 110p is incident on one region 130p. However, as described later, the combination of the pixels 110p and the regions 130p changes according to the operation of the drive unit 140.

[0062] The region 130p includes three types: a first region 130a, a second region 130b, and a third region 130c3. In the first region 130a, light is incident from the pixel 110p of the display device 110, and light of a first color is emitted. In the second region 130b, light is incident from the pixel 110p, and light of a second color different from the first color is emitted. In the third region 130c, light is incident from the pixel 110p, and light of a third color different from the first color and the second color is emitted.

[0063] In this embodiment, the first region 130a, the second region 130b, and the third region 130c are repeatedly arranged along the first direction (X direction) and the second direction (Y direction). Therefore, when focusing on a specific area of ​​the color-changing sheet 130, the first region 130a and the second region 130b are arranged along the first direction (X direction), and the first region 130a and the third region 130c are arranged along the second direction (Y direction). Figure 2B Although 100 regions 130p are shown in 10 rows and 10 columns, the present invention is not limited to this, and the number of regions 130p may be, for example, several thousand.

[0064] In this embodiment, the first region 130a is composed of a blue film, and the first color is blue. The second region 130b is composed of a green film, and the second color is green. The third region 130c is composed of a red film, and the third color is red. That is, white light is incident from the pixel 110p of the display device 110 to the first region 130a, and blue light is emitted. White light is incident from the pixel 110p to the second region 130b, and green light is emitted. White light is incident from the pixel 110p to the third region 130c, and red light is emitted. Figure 2B In the embodiment, the first region 130a emitting blue light is represented by the letter “B”, the second region 130b emitting green light is represented by the letter “G”, and the third region 130c emitting red light is represented by the letter “R”. The same is true for other embodiments and modified examples described below.

[0065] like Figure 2C As shown, the color change sheet 130 is arranged on the light emitting side of the display device 110, that is, the -Z direction side. The driving unit 140 includes, for example, an actuator, and changes the positional relationship between the display device 110 and the color change sheet 130 by moving the color change sheet 130. It should be noted that the driving unit 140 can move the display device 110, or can move both the display device 110 and the color change sheet 130. In the following description, an example in which the driving unit 140 moves the color change sheet 130 will be described.

[0066] Next, the configuration other than the above in the image display device 10 will be described.

[0067] First, the display device 110 will be described.

[0068] Figure 3 This is an end view of a display device showing the image display device of this embodiment.

[0069] 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 rows and columns. One or more LED elements 112 are arranged on each pixel 110 p of the display device 110 .

[0070] 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.

[0071] 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-based compound semiconductor represented by N (0≤X, 0≤Y, X+Y<1) can be used for the semiconductor stack 112a. The light emitted by the LED element 112 is visible light in this embodiment.

[0072] 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, 112c can be made of, for example, a metal material.

[0073] In the present embodiment, a wavelength conversion component 115 is provided on each LED element 112. Light emitted from the LED element 112 enters the wavelength conversion component 115. For example, the wavelength conversion component 115 is opposite to the light exit surface 112s of the LED element 112. The "light exit surface of the LED element" in this specification refers to the surface of the LED element from which the light incident on the imaging optical system 120 is mainly emitted. In the present embodiment, in the n-type semiconductor layer 112p3, the surface located on the opposite side to the surface opposite to the active layer 112p2 corresponds to the light exit surface 112s.

[0074] The wavelength conversion member 115 contains a phosphor. In this embodiment, the LED element 112 emits blue light. The wavelength conversion member 115 contains a phosphor that absorbs blue light and emits green light; and a phosphor that absorbs blue light and emits red light. Thus, white mixed color light consisting of blue light, green light, and red light is emitted from the wavelength conversion member 115.

[0075] Hereinafter, the optical axis of light emitted from each pixel 110p will be referred to as "optical axis C". Optical axis C is a straight line, for example, connecting point a1 and point a2, wherein point a1 has the highest brightness in the range of light irradiation from one pixel 110p in a first plane P1 parallel to the XY plane in which a plurality of pixels 110p are arranged and located on the light emitting side of the display device 110; and point a2 has the highest brightness in the range of light irradiation from the pixel 110p in a second plane P2 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 can be used as the point with the highest brightness. It should be noted that from a production point of view, the optical axis C is preferably parallel to the Z axis.

[0076] Thus, since the light emitting surface 112s of each LED element 112 is provided with a wavelength conversion component 115, the light emitted from the wavelength conversion component 115, that is, the 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 of each pixel in the direction of angle θ relative to the optical axis C can be approximated as cosine of the light intensity on the optical axis C. n The light distribution pattern is θ times, where n is greater than 0. Here, n is preferably less than 11, and more preferably 1. It should be noted that although there are multiple planes including the optical axis C of the light emitted from one pixel 110p, in each plane, the light distribution pattern of the light emitted from the pixel 110p is substantially Lambertian, and the value of n is substantially equal.

[0077] Next, the imaging optical system 120 will be described in detail.

[0078] like Figure 1 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, it has: 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 the output element 123 only needs to be incident with the light passing through the input element 121, and the intermediate element 122 may not be provided.

[0079] 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 1 As shown, a plurality of principal light rays L emitted from different positions in the display device 110 and reaching the first image IM1 via the imaging optical system 120 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 errors caused by manufacturing accuracy and assembly accuracy of the 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 between the principal light rays L is less than 10 degrees.

[0080] 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, for example, whether the imaging optical system 120 has a substantially telecentric property on the first image IM1 side can be confirmed by using the retrograde property of light by the following method. First, a light source capable of emitting parallel light, such as a laser 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, if there is a point of convergence before the light emitted from the input element 121 reaches the display device 110, that is, if there is a focus F, it is determined that the imaging optical system 120 has a substantially telecentric property on the first image IM1 side.

[0081] Since the imaging optical system 120 is substantially telecentric on the first image IM1 side, the imaging optical system 120 is mainly incident with the light that passes 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.

[0082] 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 mirror having a concave mirror surface 121a. The input element 121 reflects light emitted from the display device 110.

[0083] The intermediate element 122 is located closer to the -X side than the display device 110 and the input element 121 and is arranged to face the input element 121. The intermediate element 122 is a mirror having a concave mirror surface 122a. The intermediate element 122 further reflects the light reflected by the input element 121.

[0084] The input element 121 and the intermediate element 122 form a curved portion 120a, which 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 mirror surfaces 121a and 122a are biconical surfaces. However, the mirror surface may be a part of a spherical surface or a free-form surface.

[0085] The output element 123 is located closer to the +X side than the display device 110 and the input element 121, and is configured to be opposite to the intermediate element 122. The output element 123 is a mirror having a flat 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 substantially parallel to each other through the curved portion 120a are incident on the output element 123. The mirror surface 123a is inclined relative to the XY plane, which is the horizontal plane of the vehicle 13, in such 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 such a manner that the more it is toward the -Z direction, the more it is toward the +X direction. As shown in FIG. Figure 1 As shown, the output element 123 constitutes a direction changing section 120 b that changes the directions of the plurality of principal light rays L so that the plurality of principal light rays L that have become substantially parallel through the curved section 120 a are directed toward the formation position P of the first image IM1 .

[0086] 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 to a certain extent 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 to a certain extent in the Z direction.

[0087] 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 with each other in the light source unit 11, the light source unit 11 can be miniaturized.

[0088] However, the optical paths in the light source unit are not limited to the above. For example, all optical paths in the imaging optical system may extend in the direction along the XY plane or in the direction intersecting the XY plane. In addition, the optical paths in the light source unit may not intersect each other.

[0089] The input element 121, the intermediate element 122, and the output element 123 may be respectively composed of a main body 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 to form the mirror surface 121a, 122a, 123a. In addition, the input element 121, the intermediate element 122, and the output element 123 may each be composed entirely of a metal material.

[0090] like Figure 1 As shown, in the present embodiment, the light source unit 11 is provided in the ceiling portion 13b of the vehicle 13. The light source unit 11 is, for example, arranged on the inner side of the wall 13s1 exposed to the interior of the vehicle in the ceiling portion 13b. The wall 13s1 is provided with a through hole 13h1, 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 illuminate the space between the visual confirmer 14 and the front windshield 13a. However, the light source unit may be mounted on the top surface. The through hole 13h1 may be provided with a transparent or translucent cover having a small haze value. The haze value is preferably less than 50%, and more preferably less than 20%.

[0091] The imaging optical system 120 has been described above, but the configuration 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.

[0092] Next, the reflection unit 12 will be described.

[0093] like Figure 1 As shown, in the present embodiment, the reflection unit 12 includes a mirror 131 having a concave mirror surface 131a. The mirror 131 is arranged in a manner opposite to the front windshield 13a. The mirror 131 reflects the light emitted from the output element 123 and irradiates the front windshield 13a. The mirror 131 can be composed of a main body component made of glass or resin material, a metal film, a dielectric multilayer film or other reflective film provided on the surface of the main body component and constituting the mirror surface 131a. In addition, the mirror 131 can be composed of a metal material as a whole. In one example, the mirror surface 131a is a biconical surface. However, the mirror surface can be a part of a spherical surface or a free-form surface.

[0094] The light irradiated to the windshield 13a is reflected by the inner surface of the windshield 13a and enters the visual field 14a of the viewer 14. Thus, the viewer 14 visually recognizes the second image IM2 corresponding to the image displayed on the display device 110 on the opposite side of the windshield 13a.

[0095] 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 to the interior of 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 forms a first image IM1 through the through hole 13h1, and then irradiates the reflection unit 12 through the through hole 13h2. 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 in the ceiling portion, and the light source unit may be arranged in the instrument panel portion.

[0096] The path of light from the inner surface of the front windshield 13a toward the viewing area 14a is approximately horizontal and slightly inclined so that it is completely horizontal or the viewing area 14a side becomes higher. That is, the path is approximately parallel to the XY plane. Moreover, in this embodiment, the light source unit 11 is arranged above (+Z direction) and the reflection unit 12 is arranged below (-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 in a manner of separating the XY plane.

[0097] The above description has been given to 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 mirrors constituting the reflection unit may be more than two. It should be noted that the reflection unit 12 needs to be configured so that, for example, sunlight irradiated from the outside of the vehicle through the front windshield 13a is not reflected to the visual area 14a.

[0098] Next, the operation of the image display device 10 according to this embodiment will be described.

[0099] Figure 4 This is an end view showing the change in the positional relationship between the pixels of the display device and the region of the color change sheet.

[0100] Figure 5A to Figure 5C It is a plan view showing a change in the positional relationship between pixels of the display device and regions of the color change sheet in the present embodiment.

[0101] Figure 6 Schematic diagram showing the scene observed by a visual checker in the driver's seat in the present embodiment.

[0102] like Figure 4As shown, the driving unit 140 causes the positional relationship between the display device 110 and the color-changing sheet 130 to change between a first positional relationship in which light emitted from a pixel 110p of the display device 110 is incident on a first area 130a of the color-changing sheet 130, a second positional relationship in which light emitted from the same pixel 110p is incident on a second area 130b, and a third positional relationship in which light emitted from the same pixel 110p is incident on a third area 130c.

[0103] Therefore, if Figure 5A As shown, with the color change sheet 130 as a reference, the center 110c of one pixel 110p moves between the center of the first region 130a, the center of the second region 130b, and the center of the third region 130c along the X direction. When the arrangement period of the regions 130p in the X direction is Px, the movement amount of the center 110c of the pixel 110p along the X direction is 2Px. In this case, the driving unit 140 may also vibrate the color change sheet 130 in the X direction with the same period.

[0104] It should be noted that if Figure 5B As shown, the driving unit 140 may also move the color changing sheet 130 in the Y direction. In this case, when the arrangement period of the area 130p in the Y direction is Py, the movement amount of the center 110c of the pixel 110p in the Y direction is 2Py. In this case, the driving unit 140 may also vibrate the color changing sheet 130 in the Y direction with the same period.

[0105] In addition, if Figure 5C As shown, the driving unit 140 can also make the color-changing sheet 130 move in a ring shape on the XY plane. In this case, the movement amount of the center 110c of the pixel 110p along the X direction is Px, and along the Y direction is Py. In addition, the area arranged directly above a certain pixel 110p changes repeatedly in the order of, for example, the first area 130a (blue) → the second area 130b (green) → the third area 130c (red) → the second area 130b (green). In this case, the driving unit 140 can make the color-changing sheet 130 perform rectangular motion with the same period, or circular motion or elliptical motion.

[0106] Furthermore, when a region of a specific color is arranged directly above the pixel 110p, the display device 110 lights up the pixel 110p. For example, the pixel 110p is lit during the period when the first region 130a (blue) is arranged directly above the pixel 110p, and is turned off during other periods, thereby enabling blue light to be emitted from the pixel 110p via the color-changing sheet 130. In addition, the pixel 110p is lit during the period when the first region 130a (blue) is arranged directly above the pixel 110p and during the period when the second region 130b (green) is arranged, and is turned off during the period when the second region 130c (red) is arranged, thereby enabling blue light and green light to be emitted from the pixel 110p via the color-changing sheet 130. If the period in which the drive unit 140 moves the color-changing sheet 130 is short enough, the visual confirmer 14 can visually confirm the mixture of blue and green colors. In this way, when the driving unit 140 changes the positional relationship between the display device 110 and the color change sheet 130 , each pixel 110 p of the display device 110 can be controlled by time division, thereby allowing a color image to be emitted from the light source unit 11 .

[0107] Thus, light L constituting a color image is emitted from the color changing sheet 130. Based on this image, the imaging optical system 120 of the light source unit 11 forms a first image IM1 which is a real image at the position P. Then, the light constituting the first image IM1 is reflected by the reflection unit 12 and the front windshield 13a, and enters the visual field 14a of the visual checker 14.

[0108] Therefore, if Figure 6 As shown in FIG. 1 , the visual checker 14 visually checks the virtual image, that is, the second image IM2, on the opposite side of the front windshield 13a. The second image IM2 may be a color image or a monochrome image. Figure 6 In FIG. 1 , the second image IM2 is represented by a character string “INFORMATION”, but the second image IM2 is not limited to a character string, and may be a graphic or the like.

[0109] Next, the effects of this embodiment will be described.

[0110] In this embodiment, the positional relationship between the display device 110 and the color change sheet 130 is changed by the driving unit 140, so that a color image can be displayed by the display device 110 that emits light of a single color and the color change sheet 130 having the regions 130p of multiple colors. By setting the display device 110 as a single color display device, the light source unit 11 can be miniaturized, and thus the image display device 10 can be miniaturized.

[0111] It should be noted that it is also conceivable that three sub-pixels are provided in each pixel 110p of the display device 110, and each sub-pixel is provided with an LED element emitting blue light, an LED element emitting green light, and an LED element emitting red light, respectively, and the display device 110 displays a color image. However, in this case, the number of LED elements increases by three times compared to the present embodiment, so the display device 110 is large-scale and high-cost. In addition, it is conceivable to reduce the number of pixels by making the number of LED elements the same as that of the present embodiment. However, in this case, the fineness of the image will be reduced. In contrast, according to the present embodiment, a small light source unit and an image display device capable of displaying high-definition color images can be realized.

[0112] In addition, in the present embodiment, the imaging optical system 120 has a substantially telecentric property on the first image IM1 side, thereby making it possible to reduce the size of the light source unit 11 and the image display device 10 and display a high-quality image. This effect will be described in detail below.

[0113] Fig. 7A It is a schematic diagram showing the principle of the light source unit of this embodiment.

[0114] Figure 7B It is a schematic diagram showing the principle of the light source unit of the reference example.

[0115] exist Fig. 7A 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 in this embodiment is indicated by a dotted line. Figure 7B 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 in the reference example is indicated by a dotted line. Fig. 7A as well as Figure 7B In FIG. 1 , the imaging optical systems 120 , 2120 are represented in a simplified manner.

[0116] like Figure 7B As shown, in the light source unit 2011 of the reference example, the display device 2110 is an LCD (Liquid Crystal Display) including a plurality of pixels 2110p. Figure 7B As shown by the dotted line, the light emitted from each pixel 2110p is mainly distributed in the normal direction of the light emitting surface 2110s. In addition, although there are multiple planes including the optical axis of the light emitted from a pixel 2110p, in the display device 2110 as an LCD, the light distribution pattern of the light emitted from a pixel 2110p is different from each other in each plane. Moreover, in one plane among the multiple planes, the light emitted from each pixel 2110p has a luminous intensity in the direction of the angle θ relative to the optical axis that is approximately cosine of the luminous intensity on the optical axis.20 The light distribution pattern is θ times larger.

[0117] In such a display device 2110, even for light emitted from the same position of the display device 2110, the luminance and chromaticity will change depending on the viewing angle of the visual confirmer. Therefore, assuming that the imaging optical system 2120 obtains light emitted from each pixel 2110p in a direction other than the normal direction, even if the brightness of the light emitted from all pixels 2110p is uniform, the brightness and chromaticity in the first image IM1 will be biased. In other words, the quality of the first image IM1 is reduced. Therefore, in order to prevent the quality of the first image IM1 from being reduced, it is necessary to obtain the 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.

[0118] 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, the light source unit 11 can be miniaturized and the quality of the first image IM1 can be improved. 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 via the wavelength conversion component 15 has a substantially Lambertian distribution. Therefore, compared with 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, the angular dependence of the luminance and chromaticity of the light emitted from each pixel 110p of the display device 110 is low. In particular, as the precise Lambertian distribution is approached, that is, as the approximate formula cos n When n of θ is close to 1, the luminance and chromaticity of light emitted from each pixel 110p of the display device 110 are substantially uniform regardless of the angle. Fig. 7A As shown, even if the imaging optical system 120 acquires light passing through the focus F, that is, acquires light from a direction other than the normal direction, the deviation of the brightness and chromaticity of the first image IM1 can be suppressed, and the quality of the first image IM1 can be improved.

[0119] In addition, since the imaging optical system 120 forms the first image IM1 mainly by the light passing through the focal point F, the diffusion of the light path of the light incident on the imaging optical system 120 can be suppressed. As a result, the input element 121 can be miniaturized. Moreover, the multiple main light rays L emitted from the output element 123 are substantially parallel to each other. The fact that the multiple main light rays L emitted from the output element 123 are substantially parallel to each other means that the irradiation range of the 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 can form a small and high-quality first image IM1 can be provided.

[0120] In addition, the image display device 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 position where the first image IM1 is formed 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 optical path of light emitted from a certain point of the display device 110 gradually widens from the input element 121 toward the reflection unit 12. Therefore, in the present embodiment, in the output element 123, the range of light emitted from a certain point of the display device 110 can be reduced compared to the case where the first image IM1 is not formed. Therefore, the output element 123 can be miniaturized.

[0121] 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 .

[0122] In addition, the imaging optical system 120 in this embodiment has a curved portion 120a and a direction changing portion 120b. In this way, in the imaging optical system 120, the portion having the function of making the principal rays L parallel to each other and the portion forming the first image IM1 at a desired position are separated, thereby making the design of the imaging optical system 120 easier.

[0123] 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 to a certain extent 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 to a certain extent in the Z direction.

[0124] <Example>

[0125] Next, the light source units in the embodiment and the reference example are described.

[0126] Fig. 8A This is a graph showing the light distribution pattern of light emitted from one light emitting area in Examples 1 and 11 and the reference example.

[0127] Figure 8B This is a graph showing the uniformity of brightness of the second image in Examples 1 to 12 and the reference example.

[0128] The image display devices 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 rows and columns and an imaging optical system. Each light emitting region corresponds to each pixel 110 p of the display device 110 in the above embodiment.

[0129] exist Fig. 8A In the figure, the horizontal axis is the angle of the luminous area relative to the optical axis, and the vertical axis is the luminosity normalized by dividing the luminosity at the angle by the luminosity on the optical axis. Fig. 8A 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 light intensity in the direction of angle θ relative to the optical axis is represented by cosθ times the light intensity on the optical axis. That is, in Example 1, the light emitted from each light emitting area has an accurate Lambertian light distribution.

[0130] In Examples 2 to 12, the light emitted from each light emitting region is so configured that the light intensity in the direction of the angle θ relative to the optical axis is calculated by the cosine of the light intensity on the optical axis. n The method of the light distribution pattern expressed by θ times is set on the simulation software. It should be noted that in Example 2, n=2 is set, and from Example 2 to Example 12, n increases by 1.

[0131] In addition, checking the light distribution pattern in one plane of light emitted from the pixels of the LCD can reveal that the light distribution pattern is as follows: Fig. 8A As shown by the thin dashed line in the middle. As mentioned above, the light distribution pattern can be approximated by dividing the light intensity in the direction of the angle θ relative to the optical axis by the cosine of the light intensity on the optical axis. 20 Therefore, in the reference example, the simulation software is set such that the luminous intensity in the direction with an angle θ relative to the optical axis of each light-emitting area is calculated by the cosine of the luminous intensity on the optical axis. 20 Light distribution pattern expressed in θ times.

[0132] The imaging optical systems in Examples 1 to 12 and the reference example are all set to have telecentricity on the first image side.

[0133] Next, for each of Examples 1 to 12 and the reference example, the brightness distribution of the second image formed when the brightness of all the light-emitting areas is constant is simulated. At this time, the second image is 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.

[0134] In addition, the uniformity of the brightness of the second image at this time is evaluated. Here, "uniformity of brightness" refers to the value expressed as a percentage of the ratio of the maximum value to the minimum value of the brightness in the second image. The results are as follows: Figure 8B It should be noted that Figure 8B In the figure, the horizontal axis represents the embodiments and the reference example, and the vertical axis represents the uniformity of brightness.

[0135] like Figure 8B As shown, the larger n is, the lower the uniformity of brightness is. This is because as n increases, the brightness of the position away from the center of the second image decreases. In particular, in Example 11, that is, n=11, it can be seen that the uniformity of brightness is 30%. Since it is easy for a visual observer to distinguish between the second image and the area where the second image is not formed, it is considered that the uniformity of brightness of the second image is 30% or more.

[0136] It can be seen from this that when the imaging optical system is configured to have a substantially telecentric property, in order to suppress 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, cosine, which is an approximate formula for the light distribution pattern, n n of θ is preferably less than 11, and more preferably 1. It should be noted that, as described above, when n is not 1, the uniformity of the brightness of the second image IM2 is reduced, but in order to compensate for this uneven brightness, a predetermined brightness distribution may be set in advance in the display brightness of the display device 110. For example, in a case where the light emitted from each pixel 110p of the display device 110 passes through the imaging optical system 120, and thus the brightness of the outer edge portion of the second image IM2 is likely to be lower than the brightness of the central portion, the display device 110 may be controlled so 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 central side.

[0137] <First Modification of First Embodiment>

[0138] Next, a first modification example of the first embodiment will be described.

[0139] Fig.9A 1 is a plan view showing a color change sheet of a light source unit according to this modification.

[0140] Fig. 9B as well as Fig. 9C It is a plan view showing a change in the positional relationship between the pixels of the display device and the region of the color change sheet in this modification.

[0141] In the aforementioned first embodiment, an example in which white light is emitted from the pixel 110p of the display device 110 and three colors of light, blue, green, and red, are emitted from the color-changing sheet 130 is described. In this variation, an example in which two colors of light, green and red, are emitted from the color-changing sheet 130e is described.

[0142] like Fig.9A As shown, in the color change sheet 130e in this modification, a plurality of regions 130p are arranged in rows and columns along the first direction and the second direction. The regions 130p include two types of first regions 130a and second regions 130b. The first regions 130a and the second regions 130b are arranged alternately along the first direction (X direction) and the second direction (Y direction).

[0143] In this variation, the first region 130a is composed of a green film, and the first color is green. The second region 130b is composed of a red film, and the second color is red. That is, white light is incident on the first region 130a from the pixel 110p of the display device 110. The first region 130a allows the green component in the white light to pass through and blocks the other components. Therefore, the first region 130a emits green light. White light is incident on the second region 130b from the pixel 110p. The second region 130b allows the red component in the white light to pass through and blocks the other components. Therefore, the second region 130b emits red light.

[0144] like Fig. 9B As shown, when the color change sheet 130e is used as a reference, the center 110c of a certain pixel 110p moves between the center of the first area 130a and the center of the second area 130b along the X direction. The movement amount of the center 110c of the pixel 110p along the X direction is Px. Or, Fig. 9C As shown, the driving unit 140 can move the color change sheet 130e in the Y direction. In this case, the movement amount of the center 110c of the pixel 110p in the Y direction is Py.

[0145] According to this modification, when only two colors, green and red, are needed to display an image, the light source unit can be made smaller than in the first embodiment. In addition, compared with the first embodiment, the time for which the area 130p of the desired color is arranged directly above a certain pixel 110p becomes longer, so the brightness of the image is improved. The structure, operation, and effects in this modification other than the above are the same as those in the first embodiment.

[0146] <Second Modification of First Embodiment>

[0147] Next, a second modification of the first embodiment will be described.

[0148] Fig.10 1 is a plan view showing a color change sheet of a light source unit according to this modification.

[0149] In this modification, an example in which a transparent area is provided on the color-changing sheet 130f will be described.

[0150] like Fig.10As shown, in the color change sheet 130f in this modification, the first regions 130a and the second regions 130b are also arranged alternately along the first direction (X direction) and the second direction (Y direction).

[0151] In this variant, the first region 130a is made of a transparent film. Therefore, the first region 130a substantially transmits the white light emitted from the pixel 110p of the display device 110 as it is. Therefore, the first color is white. It should be noted that the first region 130a may be provided with an opening instead of a transparent film. The second region 130b is made of a blue film, and the second color is blue. It should be noted that in Fig.10 In the figure, the transparent first area 130a is marked with a letter “C”.

[0152] According to this modification, images of two colors, white and blue, can be displayed. It should be noted that the second area 130b can be composed of a green film or a red film. In these cases, the second color is green or red. The structure, operation and effect of this modification other than the above are the same as those of the first modification.

[0153] <Second Embodiment>

[0154] Next, a second embodiment will be described.

[0155] Fig.11 This is an end view of a display device showing the image display device of this embodiment.

[0156] Fig.12 It is a plan view showing the color change sheet of the light source unit according to the present embodiment.

[0157] In the aforementioned first embodiment, white light is emitted from the pixel 110p of the display device 110 and the color-changing sheet 130 is a color film. In the present embodiment, blue light is emitted from the pixel 110p of the display device 110 and the color-changing sheet 230 is a fluorescent sheet.

[0158] like Fig.11 As shown, in this embodiment, the wavelength conversion component 115 is not provided in the display device 110, and a plurality of recesses 112t are provided on the light emitting surface 112s of the LED element 112. As a result, the light emitted from the LED element 112 has a substantially Lambertian light distribution. The LED element 112 emits blue light. Therefore, blue light is emitted from the pixel 110p.

[0159] like Fig.12As shown, in this embodiment, a plurality of regions 230p are provided on the color change sheet 230. The shape, size, and arrangement period of the regions 230p are substantially the same as the shape, size, and arrangement period of the pixels 110p of the display device 110. The region 230p includes a first region 230a, a second region 230b, and a third region 230c.

[0160] The first region 230a is made of a transparent film. Blue light enters the first region 230a from the pixel 110p of the display device 110. The first region 230a transmits the blue light and emits it substantially as it is. Therefore, the light emitted from the first region 230a is blue light, and the first color is blue.

[0161] The second region 230b is composed of a phosphor layer. The second region 230b includes a phosphor that absorbs light emitted from the pixel 110p and emits green light. Thus, blue light is incident on the second region 230b from the pixel 110p of the display device 110, and the phosphor absorbs the blue light and emits green light. Therefore, the second color is green. The light emitted from the second region 230b has a substantially Lambertian distribution.

[0162] The third region 230c is also composed of a phosphor layer. The third region 230c includes a phosphor that absorbs light emitted from the pixel 110p and emits red light. Thus, blue light is incident on the third region 230c from the pixel 110p of the display device 110, and the phosphor absorbs the blue light and emits red light. Therefore, the third color is red. The light emitted from the third region 230c also has a substantially Lambertian light distribution.

[0163] In this embodiment, the blue light emitted from the LED element 112 is incident on the first area 230a of the color changing sheet 230. The first area 230a transmits the incident blue light as it is and emits it, so the light utilization efficiency is high. The structure, operation and effect of this embodiment other than the above are the same as those of the first embodiment.

[0164] <First Modification of Second Embodiment>

[0165] Next, a first modified example of the second embodiment will be described.

[0166] Fig.13 1 is a plan view showing a color change sheet of a light source unit according to this modification.

[0167] In the second embodiment, blue light is emitted from the pixel 110p of the display device 110, and three colors of light, blue, green and red, are emitted from the color change sheet 230. In this modified example, blue light is emitted from the pixel 110p, and two colors of light, green and red, are emitted from the color change sheet 230e.

[0168] like Fig.13 As shown, in the color change sheet 230e in this variant, the first area 230a and the second area 230b are arranged alternately along the first direction (X direction) and the second direction (Y direction). The first area 230a and the second area 230b are composed of a phosphor layer. The first area 230a includes a phosphor that absorbs blue light and radiates green light. The second area 230b includes a phosphor that absorbs blue light and radiates red light. Therefore, in this variant, the first color is green and the second color is red. The action of the drive unit 140 in this variant, that is, the change in the positional relationship between the display device 110 and the color change sheet 230e is shown in FIG. Fig. 9B or Fig. 9C shown.

[0169] According to this modification, when only two colors, green and red, are required for displaying an image, the light source unit can be made smaller than in the second embodiment. In addition, compared with the second embodiment, the time for which the area 230p of the desired color is arranged directly above a certain pixel 110p becomes longer, so the brightness of the image is improved. The structure, operation, and effects of this modification other than the above are the same as those of the second embodiment.

[0170] <Second Modification of Second Embodiment>

[0171] Next, a second modification example of the second embodiment will be described.

[0172] Fig.14 1 is a plan view showing a color change sheet of a light source unit according to this modification.

[0173] In this modification, the color-changing sheet 230f is described as an example in which a transparent area is provided.

[0174] like Fig.14 As shown, in the color change sheet 230f in this modification, the first area 230a is composed of a transparent film. Therefore, the first area 230a substantially transmits the blue light emitted from the pixel 110p of the display device 110 as it is. Therefore, the first area 230a emits blue light. Therefore, the first color is blue. It should be noted that the first area 230a can be used as an opening without a transparent film. The second area 230b is composed of a phosphor layer, which contains a phosphor that absorbs blue light and radiates green light. Therefore, the second color is green.

[0175] According to this variation, images of two colors, blue and green, can be displayed. It should be noted that the second region 230b may include a phosphor that absorbs blue light and radiates green light, or may include a phosphor that absorbs blue light and radiates red light, or may include a phosphor that absorbs blue light and radiates yellow light. In these cases, the second color is green, red or yellow, respectively. The structure, operation and effect of this variation other than the above are the same as those of the first variation of the second embodiment.

[0176] <Third Embodiment>

[0177] Next, a third embodiment will be described.

[0178] Fig.15 It is a plan view showing the color change sheet of the light source unit according to the present embodiment.

[0179] In the second embodiment, the blue light is emitted from the pixel 110 p of the display device 110 as an example. In the present embodiment, the ultraviolet light is emitted from the pixel 110 p of the display device 110 as an example.

[0180] like Fig.15 As shown, in this embodiment, the color change sheet 230g is provided with a first area 230a, a second area 230b, and a third area 230c. The first area 230a, the second area 230b, and the third area 230c are respectively composed of phosphor layers. The first area 230a includes a phosphor that absorbs ultraviolet rays and emits blue light. Therefore, the first color is blue. The second area 230b includes a phosphor that absorbs ultraviolet rays and emits green light. Therefore, the second color is green. The third area 230c includes a phosphor that absorbs ultraviolet rays and emits red light. Therefore, the third color is red. The light emitted from the first area 230a, the second area 230b, and the third area 230c has a substantially Lambertian light distribution.

[0181] In this embodiment, since all colors can be adjusted by the fluorescent material, the color selectivity is high. The structure, operation and effect of this embodiment other than the above are the same as those of the second embodiment.

[0182] <Modification of the Third Embodiment>

[0183] Next, a modification of the third embodiment will be described.

[0184] Fig.16 1 is a plan view showing a color change sheet of a light source unit according to this modification.

[0185] In the third embodiment, ultraviolet rays are emitted from the pixel 110p of the display device 110, and three colors of blue, green and red are emitted from the color changing sheet 230g. In this modified example, two colors of light are emitted from the color changing sheet 230h.

[0186] like Fig.16 As shown, in the color change sheet 230h in this modification, Fig.13 Similarly, the first region 230a and the second region 130b are arranged alternately along the first direction (X direction) and the second direction (Y direction). The first region 230a includes a phosphor that absorbs ultraviolet light and radiates light of a first color. The second region 230b includes a phosphor that absorbs ultraviolet light and radiates light of a second color. Fig.16 In the example shown, the first color is blue and the second color is green.

[0187] The combination of the first color and the second color is not limited to blue and green, and may be, for example, blue and red, blue and yellow, or green and red. The operation of the drive unit 140 in this modification, that is, the change in the positional relationship between the display device 110 and the color change sheet 230h, is as follows: Fig. 9B or Fig. 9C shown.

[0188] According to this modification, when only two colors are needed to display an image, the light source unit can be miniaturized compared to the third embodiment. In addition, the brightness of the image is improved compared to the third embodiment. The structure, operation and effect of this modification other than the above are the same as those of the third embodiment.

[0189] Fig.17 This is a diagram showing the relationship between the color of light emitted from a pixel of a display device and the structure of each region of a color change sheet.

[0190] like Fig.17 As shown, in the above-mentioned first to third embodiments and their variations, the light emitted from the pixel 110p of the display device 110 is white light, blue light or ultraviolet light, and each area of ​​the color changing sheet is a film of each color or transparent, or a fluorescent layer that radiates light of each color.

[0191] However, the present invention is not limited to Fig.17 For example, the color of the light emitted from the color changing sheet is not limited to white, blue, green, red, and yellow, but may be other colors such as orange, pink, blue, and magenta. In addition, the number of colors of the light emitted from the color changing sheet is not limited to 2 or 3, but may be 4 or more.

[0192] <Fourth Embodiment>

[0193] Next, a fourth embodiment will be described.

[0194] Fig.18 It is a plan view showing the color change sheet of the light source unit according to the present embodiment.

[0195] like Fig.18 As shown, in this embodiment, in the color changing sheet 330, in the minimum unit 330u of adjacent 2 rows and 2 columns, two second regions 330b emitting green light are arranged diagonally, and one first region 330a emitting blue light and one third region 330c emitting red light are arranged respectively. The color changing sheet 330 may be formed of a color film as in the first embodiment, may be formed of a fluorescent sheet as in the second and third embodiments, or may include a transparent region.

[0196] The operation of the driving unit 140 in this embodiment, that is, the change in the positional relationship between the display device 110 and the color change sheet 330 is as follows: Figure 5C As shown. Thus, the area arranged directly above a certain pixel 110p changes repeatedly in the order of, for example, the first area 330a (blue) → the second area 330b (green) → the third area 330c (red) → the second area 330b (green). The structure, operation and effect of this embodiment other than the above are the same as those of the first embodiment.

[0197] <Fifth Embodiment>

[0198] Next, a fifth embodiment will be described.

[0199] Fig.19 It is a plan view showing the color change sheet of the light source unit according to the present embodiment.

[0200] like Fig.19 As shown, in this embodiment, in the color changing sheet 430, the first area 430a, the second area 430b, and the third area 430c are repeatedly arranged along the first direction (X direction). On the other hand, the same type of areas are continuously arranged along the second direction (Y direction). The operation of the driving unit 140 in this embodiment, that is, the change in the positional relationship between the display device 110 and the color changing sheet 430 is shown in FIG. Figure 5A The structure, operation and effects other than those described above in this embodiment are the same as those in the first embodiment.

[0201] <Sixth Embodiment>

[0202] Next, a sixth embodiment will be described.

[0203] Fig. 20It is a plan view showing the color change sheet of the light source unit according to the present embodiment.

[0204] like Fig. 20 As shown, in this embodiment, in the color changing sheet 530, the first area 530a, the second area 530b, and the third area 530c are repeatedly arranged along the second direction (Y direction). On the other hand, the same type of areas are continuously arranged along the first direction (X direction). The operation of the driving unit 140 in this embodiment, that is, the change in the positional relationship between the display device 110 and the color changing sheet 530 is shown in FIG. Figure 5B The structure, operation and effects other than those described above in this embodiment are the same as those in the first embodiment.

[0205] <Seventh Embodiment>

[0206] Next, a seventh embodiment will be described.

[0207] Fig.21 It is an end view showing the image display device of this embodiment.

[0208] Fig. 22 Schematic diagram showing the scene observed by a visual checker in the driver's seat in the present embodiment.

[0209] like Fig.21 As shown, the automobile 1000 of this embodiment includes: a vehicle 13; and an image display device 20 fixed to the vehicle 13. The image display device 20 includes: a light source unit 11; and a reflection unit 22. The image display device 20 of this embodiment is different from the image display device 10 of the first embodiment in that the mirror surface 322a of the mirror 322 of the reflection unit 22 also serves as a reflection surface that enables the visual checker 14 to visually check the second image IM2.

[0210] The structure of the light source unit 11 in the image display device 20 is the same as that in the first embodiment. The light source unit 11 is arranged in the ceiling part 13b of the vehicle 13. The reflection unit 22 is arranged in the instrument panel part 13c of the vehicle 13. The reflection unit 22 has a mirror 322. The mirror surface 322a of the mirror 322 is, for example, a concave surface. The mirror surface 322a is configured to be at a position and angle opposite to the visual field 14a of the visual confirmer 14 when the visual confirmer 14 is in the driver's seat of the vehicle 13. For example, the mirror surface 322a faces a direction between the -X direction (rearward) and the +Z direction (upward). The angle of the mirror surface 322a can be fine-tuned according to the position of the visual field 14a of the visual confirmer 14.

[0211] Next, the operation of this embodiment will be described.

[0212] The principal light ray L emitted from the light source unit 11 travels in a direction between the +X direction (front) and the -Z direction (downward), is reflected by the mirror surface 322a of the mirror 322 of the reflection unit 22, travels in a direction between the -X direction (backward) and the +Z direction (upward), and enters the visual field 14a of the visual confirmer 14. The path of the principal light ray L from the light source unit 11 to the reflection unit 12 is located inside 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 reflection unit 22. At this time, the driving unit 140 changes the positional relationship between the display device 110 and the color change sheet 130, and controls the display device 110 in a time-sharing manner so that the first image IM1 becomes a color image including a plurality of colors.

[0213] Therefore, if Fig.21 as well as Fig. 22 As shown, the visual checker 14 can visually check the second image IM2 as a virtual image in the depth of the mirror surface 322a of the instrument panel portion 13c. The second image IM2 is formed at a distance of the mirror surface 322a, for example, 3 meters. Therefore, the visual checker 14 can view the second image IM2 without greatly moving the focus of the eyes while viewing the distant scenery through the front windshield 13a.

[0214] Next, the effects of this embodiment will be described.

[0215] The image display device 20 of this embodiment is divided into the light source unit 11 and the reflection unit 22 as in the first embodiment, and is fixed at another position in the vehicle 13. The image display device 20 requires a long optical path length to image the second image IM2 at a position several meters ahead, but by separating the light source unit 11 and the reflection 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 device 20, and the image display device 20 can be miniaturized.

[0216] In addition, in the image display device 20, the reflection unit 22 is provided with only the mirror 322. Thus, the structure of the reflection unit 22 can be simplified, and the reflection unit 22 can be miniaturized.

[0217] Furthermore, by using the mirror surface 322a disposed on the instrument panel portion 13c as a reflective surface, the viewer 14 can reliably visually check the second image IM2 without being affected by the background of the reflective surface. The configuration, operation, and effects of this embodiment other than the above are the same as those of the first embodiment.

[0218] It should be noted that the mirror 322 of the reflection unit 22 can be composed of a semi-transparent mirror or a transparent plate. Even in this case, by darkening the interior of the instrument panel portion 13c, it is possible to prevent the visual confirmer 14 from seeing the interior of the instrument panel portion 13c. Alternatively, the mirror surface 322a of the mirror 322 can be black to the extent that it can fully reflect the main light L emitted from the light source unit 11. Thus, it is possible to suppress the reduction in visibility caused by the reflection of external light on the mirror surface 322a of the mirror 322. In addition, the mirror 322 can 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 can be improved.

[0219] <Eighth Embodiment>

[0220] Next, an eighth embodiment will be described.

[0221] Fig.23 It is an end view showing the image display device of this embodiment.

[0222] Fig.24 Yes Fig.23 The display device and the reflective polarization element are shown in an enlarged cross-sectional view.

[0223] like Fig.23 as well as Fig.24 As shown, the image display device 70A of this embodiment is different from the image display device 10 of the first embodiment in that the display device 710A is provided instead of the display device 110, and is further provided with a reflective polarization element 740. The display device 710A in this embodiment is different from the display device 110 in the first embodiment in that the light emitting surface of the LED element 712 is substantially flat, and is further provided with a protective layer 714, a wavelength conversion component 715, and a light scattering component 716A. The other structures of the display device 710A are the same as those of the display device 110 in the first embodiment. In addition, the light source unit 71A of this embodiment is the same as the light source unit 11 of the first embodiment, and has a color changing sheet 130 and a driving unit 140. However, in Fig.23 In the figure, the color change sheet 130 and the driving unit 140 are omitted.

[0224] The protective layer 714 covers the plurality of LED elements 712 arranged in rows and columns. The protective layer 714 can be made of a light-transmitting material such as a polymer material having, for example, a sulfur (S) substituent or a phosphorus (P) atom group, or a high-refractive-index nanocomposite material having high-refractive-index inorganic nanoparticles introduced into a polymer matrix such as polyimide.

[0225] 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 general phosphor materials, perovskite phosphor materials, or quantum dots (Quantum Dot: QD). 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 generates light with a peak emission wavelength different from the peak emission wavelength of each LED element 712 by the light emitted from each LED element 712. The light generated by the wavelength conversion component 715 has a substantially Lambertian light distribution.

[0226] The light scattering component 716A includes: for example, a resin component having light transmittance; light scattering particles or cavities arranged 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 surface of the light scattering component 716A can be roughened to provide concave and convex portions to obtain a light scattering effect.

[0227] 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 in 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.

[0228] 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 including the incident light and the reflected light.

[0229] The visual confirmer 14 driving the vehicle 13 sometimes wears polarized sunglasses 14b to reduce the glare of sunlight or the like reflected by the accumulated water 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 accumulated water or the like, when observed from the front windshield 13a, has a particularly reduced component corresponding to P polarized light, so the polarized sunglasses 14b are designed to block most of the S polarized light. Therefore, when the visual confirmer 14 wears the polarized sunglasses 14b, most of the S polarized light contained in the light generated by the display device 710A is blocked by the polarized sunglasses 14b, and the visual confirmer 14 may have difficulty visually confirming 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 reflecting object such as accumulated water.

[0230] In this embodiment, the reflective polarizing element 740 transmits the first polarized light 710p in the light emitted from the display device 710A, and reflects the second polarized light 710s. Most of the first polarized light 710p that transmits the reflective polarizing element 740 enters the viewing area 14a without being blocked by the polarized sunglasses 14b after passing through the imaging optical system 120, the reflection unit 12, and the inner surface of the front windshield 13a. It should be noted that the incident angle of the first polarized light 710p when entering the inner surface of the front windshield 13a is set to an angle different from the Brewster angle.

[0231] Specifically, if Fig.24 As 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 generate light having a peak emission wavelength longer than the peak emission 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, the light emitted from the LED element 712 in the light emitted from the display device 710A is also referred to as "short wavelength light", and the light emitted from the wavelength conversion component 715 is also referred to as "long wavelength light". However, most of the light emitted from the LED element 712 can also be absorbed by the wavelength conversion component 715.

[0232] Most of the first polarized light 710p included in these short-wavelength light and long-wavelength light passes through the reflective polarization element 740 and exits 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 passes through the reflective polarization element 740 and exits 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, and at the same time, increase the brightness of the first image IM1. By increasing the brightness of the first image IM1, it is also possible to increase the brightness of the second image IM2. As a result, the visual confirmation person 14 can easily visually confirm the second image IM2.

[0233] In addition, a portion of the short-wavelength light contained in the second polarized light 710s may also be incident on the wavelength conversion component 715 after being reflected by the reflective polarization element 740. In this case, it can be 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 the radiated light have a roughly Lambertian distribution. In addition, the reflective polarization 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 can be converted into the first polarized light 710p.

[0234] 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 also be arranged 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 be configured without a light scattering component. In addition, by using the scattering reflection effect of the light scattering component, the display device may also be configured without a wavelength conversion component. In addition, as in the first embodiment, by utilizing the scattering reflection effect of light generated by a plurality of concave portions or a plurality of convex portions provided on the light emitting surface of the LED element, the display device may also be configured without any of the wavelength conversion component and the light scattering component.

[0235] Next, the effects of this embodiment will be described.

[0236] The light source unit 71A of this embodiment further includes a reflective polarization element 740 disposed on the display device 710A, which 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. Therefore, the ratio of the first polarized 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.

[0237] 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 can form a small and high-quality first image IM1 can be provided. It should be noted that since the plurality of LED elements 712 are discretely mounted on the substrate 111, a grainy feeling may be generated in the first image IM1. The wavelength conversion component 715 has the effect of alleviating the grainy feeling. And the light scattering component 716A can further enhance the effect of alleviating the grainy feeling. The structure, operation and effect of this embodiment other than the above are the same as those of the first embodiment.

[0238] <Ninth Embodiment>

[0239] Next, a ninth embodiment will be described.

[0240] Fig.25 It is a side view showing the light source unit according to the present embodiment.

[0241] like Fig.25 As shown, the image display device 70B of this embodiment is different from the image display device 10 of the first embodiment in that the light source unit 71B replaces the display device 110 with a display device 710A having the same structure as the eighth embodiment, and further includes a reflective polarizing element 750 and a light shielding member 760. Fig.25 , only the cross section of the light shielding component 760 is shown.

[0242] The reflective polarization element 750 may be, for example, a wire grid type reflective polarization element using a plurality of metal nanowires. The reflective polarization element 750 is disposed at a portion where a plurality of principal light rays L are substantially parallel to each other in the optical path from the display device 710A to the reflective unit 12. In the present embodiment, the 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.

[0243] The reflective polarization element 750 transmits the P-polarized light, i.e., the first polarized light 710p, and reflects the S-polarized light, i.e., the second polarized light 710s, in a manner of returning to the display device 710A. Specifically, light 710a including the first polarized light 710p and the second polarized light 710s is emitted from the display device 710A. After passing through the input element 121 and the intermediate element 122, the light 710a is incident on the reflective polarization element 750.

[0244] 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 transmitted through the reflective polarization element 750 passes through the output element 123 and then is emitted from the reflection unit 12 .

[0245] The reflective polarizing element 750 reflects most of the second polarized light 710s contained in the light 710a in a manner that returns 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 in a manner that is substantially orthogonal to the principal light ray L. The reflective polarizing element 750 reflects most of the second polarized light 710s. Therefore, most of the second polarized light 710s reflected by the reflective polarizing element 750 passes through the intermediate element 122 and the input element 121 in this order and returns to the display device 710A.

[0246] 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 passes through the reflective polarization element 750. Most of the first polarized light 710p that passes through the reflective polarization element 750 passes through the output element 123 and then exits from the reflection unit 12. Therefore, the ratio of the first polarized light 710p contained in the light emitted from the image display device 70B can be increased, and the brightness of the second image IM2 can be increased. As a result, the visual confirmer 14 can easily visually confirm the second image IM2.

[0247] 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 irradiate 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-radiate the long-wavelength light.

[0248] The light shielding member 760 is disposed between the display device 710A and the input element 121 of the imaging optical system 120. The light shielding member 760 is, for example, in the shape of 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.

[0249] 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, returns to the display device 710A through the opening 761 of the light shielding member 760. 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.

[0250] Next, the effects of this embodiment will be described.

[0251] The image display device 70B of the present 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 so as to return to the display device 710A. Therefore, the ratio of the first polarized light 710p contained in the light emitted from the image display device 70B can be increased, and the brightness of the second image IM2 can be increased.

[0252] 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 for the second polarized light 710s that returns to the display device 710A along the optical path to pass through. 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. As a result, the quality of the first image IM1 and the second image IM2 can be improved. In addition, the light shielding member 760 can suppress the stray light that does not follow the optical path of the light emitted from the display device 710A from being reflected by the reflective polarizing element 750 and the optical elements of the imaging optical system 120, and from being re-excited and scattered and reflected at an unexpected position toward the display device 710A.

[0253] It should be noted that the image display device 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 further provided on the display device 710A of the image display device 70B. In this case, the second polarized light 710s that is not completely reflected by the reflective polarizing element 740 on the display device 710A may be reflected by the reflective polarizing element 750. Therefore, the proportion of the first polarized light 710p contained in the light emitted from the image display device 70B can be increased, and the brightness of the second image IM2 can be increased. The structure, operation and effect of this embodiment other than the above are the same as those of the third embodiment.

[0254] <Modification of Ninth Embodiment>

[0255] Next, a modification of the ninth embodiment will be described.

[0256] Fig.26 It is a side view showing the light source unit according to this modification.

[0257] exist Fig.26 , only the cross section of the light shielding member 760 is shown.

[0258] like Fig.26 As shown, in this modified example, the reflective polarization element 750 is disposed between the output element 123 and the reflection unit 12. Fig.26 , the example in which the reflective polarization element 750 is located between the output element 123 and the first image IM1 is shown, but the reflective polarization element 570 may be disposed between the first image IM1 and the reflection unit 12. The structure, operation, and effects of this modification example other than the above are the same as those of the ninth embodiment.

[0259] The aforementioned embodiments and their variations are examples of the present invention, and the present invention is not limited to these embodiments and variations. For example, the present invention also includes adding, deleting or changing several components or processes in the aforementioned embodiments and variations. In addition, the aforementioned embodiments and variations can be implemented in combination with each other.

[0260] The embodiments include the following aspects.

[0261] (Aspect 1)

[0262] A light source unit, comprising:

[0263] A display device having a plurality of pixels and capable of displaying an image;

[0264] a color-changing sheet incident with light emitted from the display device;

[0265] An imaging optical system including an input element into which light emitted from the color-changing sheet is incident, and an output element into which light passing through the input element is incident, wherein the light emitted from the output element forms a first image corresponding to the image;

[0266] a driving unit that changes the positional relationship between the display device and the color-changing sheet;

[0267] The color change sheet has:

[0268] A first region from which light is incident from the pixel and light of a first color is emitted;

[0269] a second region from which light is incident from the pixel and light of a second color different from the first color is emitted;

[0270] The driving unit changes the positional relationship between the display device and the color change sheet between a first positional relationship in which light emitted from one pixel is incident on the first area and a second positional relationship in which light emitted from the one pixel is incident on the second area.

[0271] The imaging optical system has a substantially telecentric property on the first image side,

[0272] The light emitted from the display device has a substantially Lambertian light distribution.

[0273] (Aspect 2)

[0274] In the light source unit according to aspect 1, the color of the light emitted from the pixel is the first color,

[0275] The first region transmits light incident from the pixel.

[0276] (Aspect 3)

[0277] The light source unit according to aspect 1 or 2 is characterized in that:

[0278] The second region transmits light of the second color among the light emitted from the pixel. (Aspect 4)

[0279] The light source unit according to aspect 1 or 2,

[0280] The second region includes a fluorescent substance that absorbs light emitted from the pixel and radiates light of the second color.

[0281] (Aspect 5)

[0282] The light source unit according to any one of aspects 1 to 4,

[0283] The color change sheet further includes a third region where light is incident from the pixel and light of a third color different from the first color and the second color is emitted.

[0284] The driving unit changes the positional relationship between the display device and the color change sheet among the first positional relationship, the second positional relationship, and a third positional relationship in which light emitted from the one pixel is incident on the third region.

[0285] (Aspect 6)

[0286] The light source unit according to aspect 5,

[0287] In the display device, the plurality of pixels are arranged along a first direction and a second direction intersecting the first direction.

[0288] In the color change sheet, the first region, the second region, and the third region are arranged along the first direction.

[0289] (Aspect 7)

[0290] The light source unit according to aspect 5,

[0291] In the display device, the plurality of pixels are arranged along a first direction and a second direction intersecting the first direction.

[0292] In the color-changing sheet, the first region and the second region are arranged along the first direction, and the first region and the third region are arranged along the second direction.

[0293] (Aspect 8)

[0294] The light source unit according to any one of aspects 1 to 7,

[0295] 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 that is approximately equal to the cosine of the luminance on the optical axis. n The light distribution pattern is θ times larger.

[0296] The n is a value greater than 0.

[0297] (Aspect 9)

[0298] The light source unit according to aspect 8,

[0299] The n is 11 or less.

[0300] (Aspect 10)

[0301] The light source unit according to any one of aspects 1 to 9,

[0302] The display device is an LED display having a plurality of LED elements.

[0303] (Aspect 11)

[0304] The light source unit according to aspect 10,

[0305] The light emitted from the LED element has a substantially Lambertian light distribution.

[0306] (Aspect 12)

[0307] The light source unit according to aspect 10 or 11,

[0308] The display device further includes a wavelength conversion member disposed on the LED element and on which light emitted from the LED element is incident.

[0309] (Aspect 13)

[0310] The light source unit according to any one of aspects 1 to 12,

[0311] The imaging optical system includes a direction changing portion, wherein the direction changing portion includes a curved portion having the input element and the output element.

[0312] The bending portion bends the plurality of principal rays so that the plurality of principal rays are substantially parallel to each other in front of and behind the first image, and the plurality of principal rays are emitted from different positions in the display device and cross each other before entering the input element and reach the first image.

[0313] 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.

[0314] (Aspect 14)

[0315] The light source unit according to any one of aspects 1 to 13,

[0316] A light shielding member is further provided, which is arranged between the display device and the imaging optical system, has an opening for allowing a part of the light from the display device toward the imaging optical system to pass through, and shields another part of the light from the display device toward the imaging optical system.

[0317] (Aspect 15)

[0318] An image display device, comprising:

[0319] The light source unit according to any one of aspects 1 to 14;

[0320] a reflection unit separated from the light source unit and reflecting the light emitted from the imaging optical system;

[0321] The first image is formed between the light source unit and the reflection unit.

[0322] (Aspect 16)

[0323] The image display device according to claim 15,

[0324] It also includes a reflective polarization element, which is arranged in the light 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 back to the display device.

[0325] (Aspect 17)

[0326] A vehicle having:

[0327] vehicle;

[0328] The image display device according to aspect 15 or 16 is fixed to the vehicle.

[0329] Industrial Applicability

[0330] The present invention can be used in, for example, a head-up display.

[0331] Description of Reference Numerals

[0332] 10: Image display device

[0333] 11: Light source unit

[0334] 12: Reflection unit

[0335] 13: Vehicles

[0336] 13a: Front windshield

[0337] 13b: Patio

[0338] 13c: Instrument panel

[0339] 13h1, 13h2: Through hole

[0340] 13s1, 13s2: wall

[0341] 14: Visual Confirmer

[0342] 14a: Viewshed

[0343] 14b: Polarized Sunglasses

[0344] 20: Image display device

[0345] 22: Reflection unit

[0346] 70A, 70B: Image display device

[0347] 71A, 71B: Light source unit

[0348] 110: Display device

[0349] 110c: Center

[0350] 110p: Pixel

[0351] 111: Substrate

[0352] 112LED components

[0353] 112a: Semiconductor stack

[0354] 112b: Anode electrode

[0355] 112c: cathode electrode

[0356] 112p1: p-type semiconductor layer

[0357] 112p2: Active layer

[0358] 112p3: n-type semiconductor layer

[0359] 112s: light exit surface

[0360] 112t: concave part

[0361] 115: Wavelength conversion components

[0362] 118a, 118b: Wiring

[0363] 120, 2120: Imaging optical system

[0364] 120a: Bend

[0365] 120b: Direction change unit

[0366] 121: Input components

[0367] 121a, 122a: Mirror

[0368] 122: Intermediate components

[0369] 122a: Mirror

[0370] 123: Output element

[0371] 123a: Mirror

[0372] 130, 130e, 130f: Color changing sheets

[0373] 130a: First Area

[0374] 130b: Second area

[0375] 130c: Third area

[0376] 130p: Area

[0377] 131: Mirror

[0378] 131a: Mirror

[0379] 140: Drive unit

[0380] 230, 230e, 230f, 230h, 230g: Color changing sheets

[0381] 230a: First Area

[0382] 230b: Second area

[0383] 230c: Third area

[0384] 230p: Area

[0385] 322: Mirror

[0386] 322a: Mirror

[0387] 330: Color changing sheet

[0388] 330a: First area

[0389] 330b: Second area

[0390] 330c: Third area

[0391] 330u: smallest unit

[0392] 430: Color changing sheet

[0393] 430a: First Area

[0394] 430b: Second area

[0395] 430c: Third area

[0396] 530: Color changing sheet

[0397] 570: Reflective polarizing element

[0398] 710A: Display device

[0399] 710a: light

[0400] 710p: First polarized light

[0401] 710s: Second polarized light

[0402] 712: LED components

[0403] 714: Protective layer

[0404] 715: Wavelength conversion components

[0405] 716A: Light scattering components

[0406] 740: Reflective polarizing element

[0407] 750: Reflective polarizing element

[0408] 760: Light shielding parts

[0409] 761: Opening

[0410] 1000: Cars

[0411] 2011: Light source unit

[0412] 2110: Display device

[0413] 2110p: Pixel

[0414] 2110s: light exit surface

[0415] 2120: Imaging Optical Systems

[0416] C: Optical axis

[0417] F: Focus

[0418] IM1: First Image

[0419] IM2: Second Image

[0420] L: Main ray

[0421] P: Position

[0422] P1: First plane

[0423] P2: Second Plane

[0424] a1, a2: points

[0425] θ: Angle

Claims

1. A light source unit, characterized in that: have: A display device having a plurality of pixels and capable of displaying an image; a color-changing sheet incident with light emitted from the display device; An imaging optical system including an input element into which light emitted from the color-changing sheet is incident, and an output element into which light passing through the input element is incident, wherein the light emitted from the output element forms a first image corresponding to the image; a driving unit that changes the positional relationship between the display device and the color-changing sheet; The color change sheet has: A first region from which light is incident from the pixel and light of a first color is emitted; a second region from which light is incident from the pixel and light of a second color different from the first color is emitted; The driving unit changes the positional relationship between the display device and the color change sheet between a first positional relationship in which light emitted from one pixel is incident on the first area and a second positional relationship in which light emitted from the one pixel is incident on the second area. The imaging optical system has a substantially telecentric property on the first image side, The light emitted from the display device has a substantially Lambertian light distribution.

2. The light source unit according to claim 1, wherein: The color of the light emitted from the pixel is the first color, The first region transmits light incident from the pixel.

3. The light source unit according to claim 1 or 2, characterized in that: The second region transmits light of the second color among the light emitted from the pixel.

4. The light source unit according to claim 1 or 2, characterized in that: The second region includes a fluorescent substance that absorbs light emitted from the pixel and radiates light of the second color.

5. The light source unit according to any one of claims 1 to 4, wherein: The color change sheet further includes a third region where light is incident from the pixel and light of a third color different from the first color and the second color is emitted. The driving unit changes the positional relationship between the display device and the color change sheet among the first positional relationship, the second positional relationship, and a third positional relationship in which light emitted from the one pixel is incident on the third area.

6. The light source unit according to claim 5, wherein: In the display device, the plurality of pixels are arranged along a first direction and a second direction intersecting the first direction. In the color change sheet, the first region, the second region, and the third region are arranged along the first direction.

7. The light source unit according to claim 5, wherein: In the display device, the plurality of pixels are arranged along a first direction and a second direction intersecting the first direction. In the color-changing sheet, the first region and the second region are arranged along the first direction, and the first region and the third region are arranged along the second direction.

8. The light source unit according to any one of claims 1 to 7, 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 that is approximately equal to the cosine of the luminance on the optical axis. n The light distribution pattern is θ times larger. The n is a value greater than 0.

9. The light source unit according to claim 8, wherein: The n is 11 or less.

10. The light source unit according to any one of claims 1 to 9, wherein: The display device is an LED display having a plurality of LED elements.

11. The light source unit according to claim 10, wherein: The light emitted from the LED element has a substantially Lambertian light distribution.

12. The light source unit according to claim 10 or 11, characterized in that: The display device further includes a wavelength conversion member disposed on the LED element and on which light emitted from the LED element is incident.

13. The light source unit according to any one of claims 1 to 12, wherein: The imaging optical system includes a direction changing portion, wherein the direction changing portion includes a curved portion having the input element and the output element. The bending portion bends the plurality of principal rays so that the plurality of principal rays are substantially parallel to each other in front of and behind the first image, and the plurality of principal rays are emitted from different positions in the display device and cross each other before entering the input element and reach 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.

14. The light source unit according to any one of claims 1 to 13, wherein: A light shielding member is further provided, which is arranged between the display device and the imaging optical system, has an opening for allowing a part of the light from the display device toward the imaging optical system to pass through, and shields another part of the light from the display device toward the imaging optical system.

15. An image display device, characterized in that: have: The light source unit according to any one of claims 1 to 14; a reflection unit 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.

16. The image display device according to claim 15, characterized in that: It also includes a reflective polarization element, which is arranged in the light 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 back to the display device.

17. A car, characterized in that: have: vehicle; The image display device according to claim 15 or 16 fixed to the vehicle.

Images