Display device and head-up display

Abstract

To provide a display device and a head-up display in which the decrease in light quantity of transmission light can be suppressed.SOLUTION: A display device 1 includes: a backlight 30; a first image display panel 10 to which direct light from the backlight 30 is incident; and a second image display panel 20 which is arranged with a gap from the first image display panel 10 and to which transmission light of the first image display panel 10 is incident. The first image display panel 10 includes: a first polarizing plate 12 which transmits light polarizing in a first direction; and a first color filter 13 which is provided at least between the first polarizing plate 12 and the second image display panel 20. The second image display panel 20 includes: a second polarizing plate 22 which transmits light polarizing in a second direction, which is different from the first direction; and a second color filter 23 which is provided at least between the second polarizing plate 22 and the first image display panel 10. A thickness of the first color filter 13 and a thickness of the second color filter 23 are different.SELECTED DRAWING: Figure 16

Description

[Technical field]

[0001] The present invention relates to a display device and a head-up display. [Background technology]

[0002] 2. Description of the Related Art There is known a head up display (HUD) that projects an image onto a light-transmitting member such as glass and allows an observer to visually recognize the image reflected by the light-transmitting member as a virtual image (see, for example, Patent Document 1).

[0003] In a HUD, the spatial position of a virtual image visually recognized by an observer is determined by the relative positions of the display panel, the reflecting member, and the observer's viewpoint. Specifically, the greater the distance between the display panel and the reflecting member, the greater the distance from the observer's viewpoint to the virtual image, and the closer the distance between the display panel and the reflecting member, the closer the distance from the observer's viewpoint to the virtual image. In Patent Document 1, a plurality of display panels are arranged above and below at a distance from each other, and different contents are displayed on each display panel, thereby making the distance from the observer's viewpoint to the virtual image of each content different. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-168230 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the above conventional technology, the display areas of the display panels are arranged so as not to overlap in the line of sight of the observer. Therefore, there are cases where images with different distances from the observer's viewpoint to the virtual image cannot be freely arranged from the observer's viewpoint. In addition, in the above conventional technology, if the display areas of the display panels are arranged so as to overlap, the amount of transmitted light is thought to be significantly reduced.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a display device and a head-up display that can suppress a decrease in the amount of transmitted light. [Means for solving the problem]

[0007] A display device according to one embodiment of the present disclosure includes a backlight, a first image display panel into which direct light from the backlight is incident, and a second image display panel arranged with a gap between the first image display panel and into which transmitted light of the first image display panel is incident. The first image display panel includes a first polarizing plate that transmits light polarized in a first direction and blocks light polarized in a direction different from the first direction, and a first color filter provided at least between the first polarizing plate and the second image display panel. The second image display panel includes a second polarizing plate that transmits light polarized in a second direction different from the first direction and blocks light polarized in a direction different from the second direction, and a second color filter provided at least between the second polarizing plate and the first image display panel. A thickness of the first color filter and a thickness of the second color filter are different, and no other polarizing plate is provided between the first image display panel and the second image display panel.

[0008] A head-up display according to one aspect of the present disclosure is a head-up display that allows an observer to view an image reflected by a translucent member as a virtual image by superimposing the image on a real image that has passed through a translucent member that transmits and reflects incident light, and includes the display device described above, and a magnifying optical system that enlarges the image displayed on the display device and projects it onto the translucent member. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a head-up display showing an application example of a display device according to an embodiment. [Figure 2A] FIG. 2A is a schematic diagram showing the basic configuration of a HUD. [Figure 2B]FIG. 2B is a schematic diagram illustrating an equivalent configuration of the HUD shown in FIG. 2A. [Diagram 3] FIG. 3 is a diagram showing the relationship between the panel-lens distance a and the virtual distance VID between the viewpoint and the virtual image. [Figure 4] FIG. 4 is a schematic diagram showing an equivalent configuration of a HUD. [Diagram 5] FIG. 5 is a schematic diagram showing a detailed configuration of the display device according to the embodiment. [Figure 6A] FIG. 6A is a diagram showing a first example of a display mode of a HUD to which the display device according to the embodiment is applied. [Figure 6B] FIG. 6B is a diagram showing a first object viewed on a virtual image of the first image in the display mode shown in FIG. 6A. [Figure 6C] FIG. 6C is a diagram showing a second object viewed on a virtual image of the second image in the display mode shown in FIG. 6A. [Figure 6D] FIG. 6D is a cross-sectional view of the display device shown in FIG. 6A taken along line AA. [Figure 7A] FIG. 7A is a diagram showing a second example of a display mode of a HUD to which the display device according to the embodiment is applied. [Figure 7B] FIG. 7B is a diagram showing a first object viewed on a virtual image of the first image in the display mode shown in FIG. 7A. [Figure 7C] FIG. 7C is a diagram showing a second object viewed on a virtual image of the second image in the display mode shown in FIG. 7A. [Figure 7D] FIG. 7D is a cross-sectional view of the display device shown in FIG. 7A taken along line AA. [Figure 8] FIG. 8 is a diagram conceptually showing a state in which the second image is displayed on the second image display panel in a display device according to a comparative example. [Figure 9] FIG. 9 is a graph showing an example of an emission spectrum of a backlight. [Figure 10] FIG. 10 is a graph showing an example of the spectral transmittance of the first color filter and the second color filter in a display device according to a comparative example. [Figure 11]FIG. 11 is a graph showing an example of a transmitted light spectrum of a first color filter and an incident light spectrum of a second color filter in a display device according to a comparative example. [Figure 12] FIG. 12 is a schematic diagram showing an example of a color reproduction gamut of a second image in a state in which the second image is displayed on a second image display panel in a display device according to a comparative example. [Figure 13] FIG. 13 is a diagram conceptually showing a state in which the first image is displayed on the first image display panel in a display device according to a comparative example. [Figure 14] FIG. 14 is a graph showing an example of a transmitted light spectrum of a first color filter and an incident light spectrum of a second color filter in a display device according to a comparative example. [Figure 15] FIG. 15 is a schematic diagram showing an example of a color reproduction gamut of a first image in a state in which the first image is displayed on a first image display panel in a display device according to a comparative example. [Figure 16] FIG. 16 is a diagram conceptually illustrating a state in which the second image is displayed on the second image display panel in the display device according to the first embodiment. [Figure 17] FIG. 17 is a graph showing an example of the spectral transmittance of the first color filter and the second color filter in the display device according to the first embodiment. [Figure 18] FIG. 18 is a graph showing an example of a transmitted light spectrum of a first color filter and an incident light spectrum of a second color filter in the display device according to the first embodiment. [Figure 19] FIG. 19 is a schematic diagram showing an example of a color gamut of the second image when the second image is displayed on the second image display panel in the display device according to the first embodiment. [Figure 20] FIG. 20 is a diagram conceptually illustrating a state in which the first image is displayed on the first image display panel in the display device according to the first embodiment. [Figure 21] FIG. 21 is a graph showing an example of a transmission light spectrum of the first color filter in the display device according to the first embodiment. [Figure 22]FIG. 22 is a schematic diagram showing an example of a color gamut of a first image in a state in which the first image is displayed on a first image display panel in the display device according to the first embodiment. [Diagram 23] FIG. 23 is a diagram conceptually illustrating a state in which the second image is displayed on the second image display panel in the display device according to the second embodiment. [Figure 24] FIG. 24 is a graph showing an example of the spectral transmittance of the first color filter and the second color filter in the display device according to the second embodiment. [Diagram 25] FIG. 25 is a graph showing an example of a transmitted light spectrum of a first color filter and an incident light spectrum of a second color filter in the display device according to the second embodiment. [Figure 26] FIG. 26 is a schematic diagram showing an example of a color gamut of the second image when the second image is displayed on the second image display panel in the display device according to the second embodiment. [Figure 27] FIG. 27 is a diagram conceptually illustrating a state in which the first image is displayed on the first image display panel in the display device according to the second embodiment. [Figure 28] FIG. 28 is a graph showing an example of a transmission light spectrum of the first color filter in the display device according to the second embodiment. [Figure 29] FIG. 29 is a schematic diagram showing an example of a color gamut of a first image when the first image is displayed on a first image display panel in the display device according to the second embodiment. [Diagram 30] FIG. 30 is a first schematic diagram comparing the color gamut of the display device according to the first embodiment with the color gamut of the display device according to the second embodiment. [Diagram 31] FIG. 31 is a second schematic diagram comparing the color gamut of the display device according to the first embodiment with the color gamut of the display device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The form (embodiment) for carrying out the present disclosure will be described in detail with reference to the drawings. The present disclosure is not limited by the contents described in the following embodiment. The components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the components described below can be appropriately combined. The disclosure is merely an example, and those that a person skilled in the art can easily imagine appropriate modifications while maintaining the gist of the disclosure are naturally included in the scope of the present disclosure. In addition, in order to make the explanation clearer, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment, but they are merely examples and do not limit the interpretation of the present disclosure. In addition, in this specification and each figure, elements similar to those described above with respect to the previously mentioned figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate.

[0011] 1 is a schematic diagram of a head-up display showing an application example of a display device according to an embodiment. A head-up display (HUD, hereinafter also simply referred to as "HUD") 100 includes a display device 1 and a magnifying optical system 2 that magnifies an image displayed on the display device 1 and projects the image on a light-transmitting member FG.

[0012] The light-transmitting member FG is a member having light-transmitting properties, such as glass or resin. Examples of the light-transmitting member FG include a windshield or a combiner of a vehicle. The light-transmitting member FG may be any member that transmits and reflects incident light, and is not limited to a windshield or a combiner of a vehicle.

[0013] A lens is an example of the magnifying optical system 2. However, the present invention is not limited to this, and one magnifying optical system 2 may be configured with a plurality of optical members such as a plane mirror or a concave mirror.

[0014] The display device 1 includes, as main components, a first image display panel 10 for displaying a first image, a second image display panel 20 for displaying a second image, and a backlight 30.

[0015] The backlight 30 irradiates planar light (light L) toward the first image display panel 10. As shown by the solid arrow in FIG. 1, the light L emitted from the backlight 30 passes through the first image display panel 10, the second image display panel 20, and the magnifying optical system 2 in that order, and is reflected by the light-transmitting member FG to reach the viewpoint of the observer OB. The image output area of ​​the first image display panel 10 and the image output area of ​​the second image display panel 20 overlap in the optical axis direction of the magnifying optical system. In other words, the image output area of ​​the first image display panel 10 and the image output area of ​​the second image display panel 20 overlap in the line of sight direction of the display device 1 reflected by the light-transmitting member FG as seen from the viewpoint of the observer OB. As a result, the virtual image VIR of the first image reflected by the light-transmitting member FG and the virtual image VIF of the second image are visually recognized by the observer OB in a state where they overlap in the direction shown by the dashed arrow in FIG. 1.

[0016] In the following description, the virtual distance from the viewpoint of the observer OB to the virtual image VIR of the first image and the virtual image VIF of the second image reflected by the light-transmitting member FG is also simply referred to as the “virtual distance.” Also, the virtual positions of the virtual image VIR of the first image and the virtual image VIF of the second image reflected by the light-transmitting member FG are also simply referred to as the “virtual position.”

[0017] In this disclosure, the "optical axis of the magnifying optical system" does not refer to the individual optical axes of each optical element when the magnifying optical system 2 is composed of multiple optical elements, but rather to the optical axis that passes through a single magnifying optical system 2 composed of multiple optical elements and enters the second image display panel 20.

[0018] 1, the first image display panel 10 and the second image display panel 20 are disposed approximately parallel to a plane (XY plane) perpendicular to the optical axis of the magnifying optical system 2. As a result, a virtual image VIR of the first image and a virtual image VIF of the second image viewed by the observer OB are viewed by the observer OB on a virtual plane (VX-VY plane) approximately parallel to the direction indicated by the dashed arrow in FIG.

[0019] In addition, in the HUD 100 shown in FIG. 1, the distance from the viewpoint of the observer OB to the first image displayed on the first image display panel 10 is longer than the distance from the viewpoint of the observer OB to the second image displayed on the second image display panel 20. As a result, the virtual image VIR of the first image displayed on the first image display panel 10 is viewed by the observer OB at a position farther away in the direction indicated by the dashed arrow in FIG. 1 than the virtual image VIF of the second image displayed on the second image display panel 20. In other words, the virtual image VIR of the first image displayed on the first image display panel 10 is viewed as being located behind the virtual image VIF of the second image displayed on the second image display panel 20. In addition, in the HUD 100 shown in FIG. 1, the first image displayed on the first image display panel 10 and the second image displayed on the second image display panel 20 overlap in the line of sight of the observer OB. As a result, the virtual image VIR of the first image displayed on the first image display panel 10 is viewed by the observer OB while overlapping with the virtual image VIF of the second image displayed on the second image display panel 20. In such a virtual image optical system, if the first image displayed on the first image display panel 10 and the second image displayed on the second image display panel 20 are images of the same size and shape, the virtual image VIR of the first image viewed by the observer OB will be larger than the virtual image VIF of the second image.

[0020] The relative positional relationship between the virtual images VIR and VIF visually recognized by the observer OB in the HUD 100 will be described below.

[0021] Figure 2A is a schematic diagram showing the basic configuration of a HUD, and Figure 2B is a schematic diagram showing an equivalent configuration of the HUD shown in Figure 2A.

[0022] An eye box EB shown in Fig. 2A indicates a range in which an observer OB can view a virtual image VI. As shown in Fig. 2B, when the lens O and image display panel D of the HUD shown in Fig. 2A are arranged in the line of sight of the observer OB, a distance a (mm) between the image display panel D and the center line of the lens O, a virtual distance b (mm) between the virtual image VI and the center line of the lens O, and a focal length f (mm) of the lens O have the relationship shown in the following formula (1). The distance a between the image display panel D and the center line of the lens O is set to be less than the focal length f of the lens O (f>a).

[0023]

number

[0024] The virtual distance VID (mm) from the viewpoint of observer OB to virtual image VI is expressed by the following formula (2) using the distance e from the center line of lens O to the viewpoint of observer OB. Fig. 3 is a diagram showing the relationship between the distance a between the panel and the lens and the virtual distance VID between the viewpoint and the virtual image.

[0025]

number

[0026] 3, the longer the distance a from the image display panel D to the center line of the lens O, the farther the virtual distance VID from the viewpoint of the observer OB to the virtual image VI becomes. Also, the closer the distance a from the image display panel D to the center line of the lens O becomes to the focal length f, the greater the change in the virtual distance VID from the viewpoint of the observer OB to the virtual image VI with respect to the change in the distance a becomes.

[0027] Fig. 4 is a schematic diagram showing an equivalent configuration of a HUD. As described above, in the schematic configuration of the HUD 100 shown in Fig. 1, the first image display panel 10 is disposed farther from the magnifying optical system 2 than the second image display panel 20 in the direction (Z direction) perpendicular to the optical axis of the magnifying optical system 2, in other words, the XY plane perpendicular to the optical axis of the magnifying optical system 2. Specifically, in the equivalent configuration of the HUD 100 shown in Fig. 4, the distance a1 from the first image display panel 10 to the center line of the lens O (magnifying optical system 2) is greater than the distance a2 from the second image display panel 20 to the center line of the lens O (magnifying optical system 2) (a1>a2).

[0028] A virtual distance VID1 from the viewpoint of the observer OB to the virtual image VIR of the first image displayed on the first image display panel 10 corresponds to a distance a1 from the first image display panel 10 to the center line of the lens O (magnifying optical system 2). A virtual distance VID2 from the viewpoint of the observer OB to the virtual image VIF of the second image displayed on the second image display panel 20 corresponds to a distance a2 from the second image display panel 20 to the center line of the lens O (magnifying optical system 2). Therefore, in the equivalent configuration of the HUD 100 shown in FIG. 4, the virtual distance VID1 from the viewpoint of the observer OB to the virtual image VIR of the first image displayed on the first image display panel 10 is larger than the virtual distance VID2 from the viewpoint of the observer OB to the virtual image VIF of the second image displayed on the second image display panel 20 (VID1>VID2).

[0029] As a result, the virtual image VIR of the first image displayed on the first image display panel 10 is viewed at a virtual position farther away from the observer OB than the virtual image VIF of the second image displayed on the second image display panel 20.

[0030] In the present disclosure, as described above, the image output area of ​​the first image display panel 10 and the image output area of ​​the second image display panel 20 overlap in the optical axis direction of the magnifying optical system 2. In other words, the image output area of ​​the first image display panel 10 and the image output area of ​​the second image display panel 20 overlap in the line of sight direction of the observer OB. As a result, the virtual image VIR of the first image and the virtual image VIF of the second image reflected by the light-transmitting member FG overlap in the direction indicated by the dashed arrow in FIG. 1 and are visually recognized by the observer OB. In such an embodiment, the display device 1 according to the present disclosure is capable of arranging the first object on the virtual image VIR of the first image and the second object on the virtual image VIF of the second image at arbitrary positions in the region where the virtual image VIR of the first image and the virtual image VIF of the second image overlap in the direction indicated by the dashed arrow in FIG. 1. Hereinafter, a detailed configuration of the display device 1 that enables the above-mentioned display embodiment will be described.

[0031] FIG. 5 is a schematic diagram showing a detailed configuration of the display device according to the embodiment.

[0032] The first image display panel 10 receives direct light from the backlight 30 .

[0033] The second image display panel 20 is disposed with a gap S provided between it and the first image display panel 10. The second image display panel 20 receives transmitted light from the first image display panel 10.

[0034] In the display device 1 according to the embodiment, the first image display panel 10 includes a first liquid crystal panel 11, a first polarizing plate 12, and a first color filter 13. The first color filter 13 is provided between the first polarizing plate 12 and the second image display panel 20. The first liquid crystal panel 11 is provided between the first polarizing plate 12 and the first color filter 13.

[0035] Moreover, in the display device 1 according to the embodiment, the second image display panel 20 includes a second liquid crystal panel 21, a second polarizing plate 22, and a second color filter 23. The second color filter 23 is provided between the second polarizing plate 22 and the first image display panel 10. The second liquid crystal panel 21 is provided between the second color filter 23 and the first color filter 13.

[0036] The first liquid crystal panel 11 and the second liquid crystal panel 21 are transmissive liquid crystal display panels, and have a plurality of pixels driven by, for example, an active matrix method. The plurality of pixels are two-dimensionally arranged along the plate surfaces of the first liquid crystal panel 11 and the second liquid crystal panel 21. In an image output region (not shown) in which the plurality of pixels are arranged, the plurality of pixels are individually controlled to form a light transmission pattern corresponding to the first image and the second image. As a result, when incident light passes through the image output region of the first liquid crystal panel 11, the amount of light is adjusted according to the gradation value of the pixel of the first liquid crystal panel 11 provided at the position corresponding to the first object OBJ1 displayed on the first image display panel 10, and the light is emitted as transmitted light. Also, when incident light passes through the image output region of the second liquid crystal panel 21, the amount of light is adjusted according to the gradation value of the pixel of the second liquid crystal panel 21 provided at the position corresponding to the second object OBJ2 displayed on the second image display panel 20, and the light is emitted as transmitted light.

[0037] The first polarizing plate 12 and the second polarizing plate 22 are arranged in a state in which their transmission axes are perpendicular to each other with respect to the incident light (crossed Nicols). In the display device 1 according to the present disclosure, no polarizing plate is provided between the first image display panel 10 and the second image display panel 20.

[0038] The first polarizing plate 12 is an optical member that transmits light polarized in a first direction and blocks light polarized in a direction different from the first direction. Specifically, the first polarizing plate 12 is a linear polarizing plate having a transmission axis in, for example, the Y direction.

[0039] The second polarizing plate 22 is an optical member that transmits light polarized in a second direction different from the first direction and blocks light polarized in a direction different from the second direction. Specifically, the second polarizing plate 22 is a linear polarizing plate having a transmission axis in, for example, the X direction.

[0040] The first color filter 13 and the second color filter 23 each include a red color resist that transmits red light, a green color resist that transmits green light, and a blue color resist that transmits blue light. The color resists of each color are provided corresponding to a plurality of pixels of the first liquid crystal panel 11 and the second liquid crystal panel 21, respectively. The color resists of each color are applied, for example, to glass substrates constituting the first liquid crystal panel 11 and the second liquid crystal panel 21. In other words, the first color filter 13 and the second color filter 23 each have a first region that transmits a first light (e.g., red light) and attenuates light of at least a wavelength other than the first light, a second region that transmits a second light (e.g., green light) having a wavelength different from the first light (e.g., red light) and attenuates light of at least a wavelength other than the second light, and a third region that transmits a third light (e.g., blue light) having a wavelength different from the first light (e.g., red light) and the second light (e.g., green light) and attenuates light of at least a wavelength other than the third light. In the present disclosure, the area where the red color resist is applied corresponds to the first area, the area where the green color resist is applied corresponds to the second area, and the area where the blue color resist is applied corresponds to the third area.

[0041] In the configuration of the display device 1 according to the above-mentioned embodiment 1, the gradation value as seen from the viewpoint of the observer OB is expressed by the following formula (3) using the gradation value R at a corresponding position in the image output region of the first liquid crystal panel 11 and the gradation value F at a corresponding position in the image output region of the second liquid crystal panel 21. In the following formula (3), the gradation value R and the gradation value F are normalized with a maximum value of 1. Note that the initial alignment and rotation direction of the liquid crystal molecules of the first liquid crystal panel 11 and the second liquid crystal panel 21 are determined so as to satisfy the following formula (3).

[0042] A = R + F - 2 × R × F (3)

[0043] For example, when the gradation value R at a position corresponding to the first object OBJ1 displayed on the first image display panel 10 is 0.8 (R=0.8) and the gradation value F is 0 (F=0), the gradation value A of the first object OBJ1 viewed by the observer OB is 0.8 (A=0.8).

[0044] Furthermore, for example, when the gradation value R at the position corresponding to the second object OBJ2 displayed on the second image display panel 20 is 0 (R=0) and the gradation value F is 0.5 (F=0.4), the gradation value A of the second object OBJ2 viewed by the observer OB is 0.4 (A=0.4).

[0045] Furthermore, for example, in a display mode (described later) in which a first object OBJ1 displayed on the first image display panel 10 and a second object OBJ2 displayed on the second image display panel 20 overlap in the line of sight of an observer OB to form one composite object COMP_OBJ, when the gradation value R at the position corresponding to the composite object COMP_OBJ is 0.8 (R=0.8) and the gradation value F is 0.4 (F=0.4), the gradation value A of the composite object COMP_OBJ viewed by the observer OB is 0.56 (A=0.56).

[0046] In the HUD 100 to which the display device 1 according to the embodiment is applied, when the composite object COMP_OBJ is visually recognized by the observer OB, the first object OBJ1 on the virtual image VIR of the first image is smaller than the second object OBJ2 on the virtual image VIF of the second image. Also, when the viewpoint of the observer OB shifts, the first object OBJ1 on the virtual image VIR of the first image and the second object OBJ2 on the virtual image VIF of the second image are visually recognized as being misaligned, which may give the observer OB a visually uncomfortable feeling.

[0047] In the configuration of the present disclosure which allows an observer to view a virtual image VIR of the first image and a virtual image VIF of the second image, the area in which the first object OBJ1 and the second object OBJ2 are misaligned and viewed by the observer OB is limited to the area EB2-EB1 where the eyebox EB1 in which the virtual image VIR of the first image is viewable and the eyebox EB2 in which the virtual image VIF of the second image is viewable do not overlap (see Figure 4).

[0048] Hereinafter, a specific example of a display mode of the HUD 100 to which the display device 1 according to the embodiment is applied will be described.

[0049] Fig. 6A is a diagram showing a first example of a display mode of a HUD to which a display device according to an embodiment is applied. Fig. 6B is a diagram showing a first object visually recognized on a virtual image of a first image in the display mode shown in Fig. 6A. Fig. 6C is a diagram showing a second object visually recognized on a virtual image of a second image in the display mode shown in Fig. 6A. Fig. 6D is a cross-sectional view of the display device shown in Fig. 6A along line AA.

[0050] In the display mode shown in Figure 6A, in the area where the first image displayed on the first image display panel 10 and the second image displayed on the second image display panel 20 overlap in the line of sight of the observer OB, in other words, in the area where the virtual image VIR of the first image and the virtual image VIF of the second image overlap in the direction indicated by the dashed arrow in Figure 1, the first object OBJ1 is positioned relatively higher and the second object OBJ2 is positioned relatively lower, and is viewed by the observer OB.

[0051] Fig. 7A is a diagram showing a second example of a display mode of a HUD to which a display device according to an embodiment is applied. Fig. 7B is a diagram showing a first object visually recognized on a virtual image of a first image in the display mode shown in Fig. 7A. Fig. 7C is a diagram showing a second object visually recognized on a virtual image of a second image in the display mode shown in Fig. 7A. Fig. 7D is a cross-sectional view of the display device shown in Fig. 7A along line AA.

[0052] In the display mode shown in FIG. 7A, the first object OBJ1 displayed on the first image display panel 10 and the second object OBJ2 displayed on the second image display panel 20 overlap in the line of sight of the observer OB to form one composite object COMP_OBJ. In other words, in the area where the virtual image VIR of the first image and the virtual image VIF of the second image overlap in the direction indicated by the dashed arrow in FIG. 1, the observer OB visually recognizes the first object OBJ1 and the second object OBJ2 as one composite object COMP_OBJ overlapping in the direction indicated by the dashed arrow in FIG. 1. In addition, as the gradation value of the first object OBJ1 increases, the gradation value of the second object OBJ2 decreases. As a result, in the area where the virtual image VIR of the first image and the virtual image VIF of the second image overlap in the direction indicated by the dashed arrow in FIG. 1 from the viewpoint of the observer OB, the observer OB visually recognizes the composite object COMP_OBJ that has the illusion of being tilted from bottom to top, from the front to the back.

[0053] In this way, the HUD 100 to which the display device 1 of the embodiment is applied can freely position the first object OBJ1 on the virtual image VIR of the first image and the second object OBJ on the virtual image VIF of the second image in an area visible to the observer OB with the virtual image VIR of the first image and the virtual image VIF of the second image overlapping in the direction indicated by the dashed arrow in Figure 1.

[0054] In addition, in a display mode in which the first object OBJ1 displayed on the first image display panel 10 and the second object OBJ2 displayed on the second image display panel 20 overlap in the line of sight of the observer OB to form one composite object COMP_OBJ, in at least one direction of the area in which the virtual image VIR of the first image and the virtual image VIF of the second image overlap in the direction indicated by the dashed arrow in Figure 1, the gradation value of the first object OBJ1 is controlled to increase as the gradation value of the second object OBJ2 decreases, thereby making the observer OB perceive the composite object COMP_OBJ as tilted in one direction.

[0055] In the display device 1 according to the embodiment, the first image display panel 10 is irradiated with emitted light L from the backlight 30. The transmitted light of the first image displayed on the first image display panel 10 further passes through the second image display panel 20. At this time, the amount of light of the first object OBJ1 on the first image displayed on the first image display panel 10 is reduced by passing through the second color filter 23 provided on the second image display panel 20.

[0056] In the display device 1 according to the embodiment, the second image display panel 20 is irradiated with transmitted light through the first image display panel 10. At this time, the amount of transmitted light through the first image display panel 10 irradiated to the second image display panel 20 is reduced by transmitting the light through the first color filter 13 provided on the first image display panel 10.

[0057] In a liquid crystal display device using a so-called color filter system, the color reproduction range can be expanded by making the color of the color filter darker. On the other hand, when the color of the color filter is made darker, the light transmittance decreases, the amount of transmitted light decreases, and the brightness of the display screen decreases. In other words, by making the color of the color filter lighter and narrowing the color reproduction range, the decrease in the amount of transmitted light can be suppressed.

[0058] Hereinafter, the color reproduction range of the display device according to the comparative example will be described with reference to FIGS.

[0059] Fig. 8 is a conceptual diagram showing a state in which a second image is displayed on a second image display panel in a display device according to a comparative example. In Fig. 8, arrows indicate light passing through a red color resist CFR (first region) corresponding to a sub-pixel that reproduces red in the second image, a green color resist CFG (second region) corresponding to a sub-pixel that reproduces green in the second image, and a blue color resist CFB (third region) corresponding to a sub-pixel that reproduces blue in the second image. In the comparative example, the characteristics (color depth) of the first color filter 13 and the second color filter 23 are approximately the same. Specifically, in the example shown in Fig. 8, the thicknesses in the Z direction of the first color filter 13 and the second color filter 23 are approximately the same.

[0060] Fig. 9 is a graph showing an example of the emission spectrum of a backlight. The horizontal axis in Fig. 9 indicates the wavelength, and the vertical axis indicates the emission intensity (relative value) of the backlight. Fig. 9 shows an example with peaks around 630 nm corresponding to red light, around 550 nm corresponding to green light, and around 440 nm corresponding to blue light.

[0061] FIG. 10 is a graph showing an example of the spectral transmittance of the first color filter and the second color filter in the display device according to the comparative example. The horizontal axis in FIG. 10 indicates the wavelength, and the vertical axis indicates the transmittance of each color resist. In FIG. 10, the solid line indicates the transmittance of the red color resist, the dashed line indicates the transmittance of the green color resist, and the dashed line indicates the transmittance of the blue color resist. The red color resist (first region) has a characteristic of transmitting light in a predetermined wavelength band including around 630 nm corresponding to red light, and attenuating light outside the wavelength band. The green color resist (second region) has a characteristic of transmitting light in a predetermined wavelength band including around 550 nm corresponding to green light, and attenuating light outside the wavelength band. The blue color resist (third region) has a characteristic of transmitting light in a predetermined wavelength band including around 440 nm corresponding to blue light, and attenuating light outside the wavelength band.

[0062] Fig. 11 is a graph showing an example of the spectrum of transmitted light of the first color filter and the spectrum of incident light of the second color filter in a display device according to a comparative example. The horizontal axis in Fig. 11 indicates wavelength, and the vertical axis indicates the light intensity (relative value) of the transmitted light of the first color filter when the first image display is gradation 0 for each color. In Fig. 11, the solid line indicates the spectrum of light transmitted through the red color resist, the dashed line indicates the spectrum of light transmitted through the green color resist, and the dashed line indicates the spectrum of light transmitted through the blue color resist. Note that the two-dot chain line in Fig. 11 indicates the spectrum of light incident on the second image displayed on the second image display panel 20 as a result of transmitting through the first color filter.

[0063] The light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the color resists of each color of the second color filter 23 of the second image display panel 20, respectively.

[0064] More specifically, the combined light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the red color resist of the second color filter 23 of the second image display panel 20. Moreover, the combined light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the green color resist of the second color filter 23 of the second image display panel 20. Moreover, the combined light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the blue color resist of the second color filter 23 of the second image display panel 20.

[0065] As a result, the incident light spectrum of the second image displayed on the second image display panel 20 is represented as a composite light spectrum combining the light transmitted through each color resist of the first color filter 13 of the first image display panel 10, as shown by the dotted line in Figure 11.

[0066] The color reproduction gamut of the second image displayed on the second image display panel 20 is determined by the light transmitted through each color resist of the second color filter 23. Fig. 12 is a schematic diagram showing an example of the color reproduction gamut of the second image when the second image is displayed on the second image display panel in a display device according to a comparative example. The solid line shown in Fig. 12 indicates the color reproduction gamut of the second image transmitted through the second image display panel 20. The dashed line shown in Fig. 12 indicates the color reproduction gamut of the transmitted light of the first image display panel 10.

[0067] Fig. 13 is a conceptual diagram showing a state in which a first image is displayed on a first image display panel in a display device according to a comparative example. In Fig. 13, arrows indicate light passing through a red color resist CFR (first region) corresponding to a sub-pixel that reproduces red in the first image, a green color resist CFG (second region) corresponding to a sub-pixel that reproduces green in the first image, and a blue color resist CFB (third region) corresponding to a sub-pixel that reproduces blue in the first image.

[0068] Fig. 14 is a graph showing an example of the transmitted light spectrum of the first color filter and the incident light spectrum of the second color filter in a display device according to a comparative example. The horizontal axis in Fig. 14 indicates wavelength, and the vertical axis indicates the light intensity (relative value) of the transmitted light of the first color filter when the first image display is at gradation 0 for each color. In Fig. 14, the solid line indicates the spectrum of light transmitted through the red color resist, the dashed line indicates the spectrum of light transmitted through the green color resist, and the dashed line indicates the spectrum of light transmitted through the blue color resist. The peak value of each spectrum shown in Fig. 14 corresponds to the gradation value of each sub-pixel that reproduces each color in the second image.

[0069] Light emitted from a backlight 30 shown in FIG.

[0070] The light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the color resists of each color of the second color filter 23 of the second image display panel 20, respectively.

[0071] More specifically, light transmitted through the red color resist of the first color filter 13 of the first image display panel 10 is incident on each color resist of the second color filter 23 of the second image display panel 20. Light transmitted through the green color resist of the first color filter 13 of the first image display panel 10 is incident on each color resist of the second color filter 23 of the second image display panel 20. Light transmitted through the blue color resist of the first color filter 13 of the first image display panel 10 is incident on each color resist of the second color filter 23 of the second image display panel 20.

[0072] Specifically, for example, when red is displayed on the first image display panel 10, light that has passed through the red color register of the first image display panel 10 enters the second image display panel 20. The red light that has entered the second image display panel 20 passes through each color register of the second image display panel 20, and a color synthesized by the lights that have passed through each color register of the second image display panel 20 is visually recognized by an observer.

[0073] Furthermore, for example, when green is displayed on the first image display panel 10, light that has passed through the green color register of the first image display panel 10 enters the second image display panel 20. The green light that has entered the second image display panel 20 passes through each color register of the second image display panel 20, and a color synthesized by the lights that have passed through each color register of the second image display panel 20 is visually recognized by an observer.

[0074] Furthermore, for example, when blue is displayed on the first image display panel 10, light that has passed through the blue color register of the first image display panel 10 enters the second image display panel 20. The blue light that has entered the second image display panel 20 passes through each color register of the second image display panel 20, and a color synthesized by the lights that have passed through each color register of the second image display panel 20 is visually recognized by an observer.

[0075] The color reproduction gamut of the first image displayed on the first image display panel 10 is determined by the light transmitted through each color resist of the second color filter 23. Fig. 15 is a schematic diagram showing an example of the color reproduction gamut of the first image when the first image is displayed on the first image display panel in a display device according to a comparative example. The solid line shown in Fig. 15 indicates the color reproduction gamut of the first image transmitted through the second image display panel 20. The dashed line shown in Fig. 15 indicates the color reproduction gamut of the first image transmitted through the first image display panel 10.

[0076] In the display device according to the comparative example, as described above, the thicknesses of the first color filter 13 and the second color filter 23 in the Z direction are substantially the same. Therefore, as shown in FIG. 12 and FIG. 15, the color reproduction range of the first image by the first color filter 13 and the color reproduction range of the second image by the second color filter 23 are substantially the same. In the present disclosure, no polarizing plate is provided between the first image display panel 10 and the second image display panel 20, and the first polarizing plate 12 and the second polarizing plate 22 are arranged in a crossed Nicol configuration, so that the display images of both the first image display panel 10 and the second image display panel 20 arranged to overlap in the line of sight of the observer OB can be viewed. However, in order to further improve the visibility of the display images, it is desirable to suppress the decrease in the amount of transmitted light.

[0077] Below, we will explain a specific configuration that can suppress the reduction in the amount of transmitted light in a configuration in which the display images of both the first image display panel 10 and the second image display panel 20, which are arranged overlapping in the line of sight of the observer OB, can be viewed.

[0078] (Embodiment 1) Fig. 16 is a diagram conceptually illustrating a state in which a second image is displayed on a second image display panel in the display device according to embodiment 1. In Fig. 16, arrows indicate light passing through a red color resist CFR (first region) corresponding to a subpixel that reproduces red in the second image, a green color resist CFG (second region) corresponding to a subpixel that reproduces green in the second image, and a blue color resist CFB (third region) corresponding to a subpixel that reproduces blue in the second image.

[0079] In the display device 1 according to the first embodiment, the color densities of the first color filter 13 and the second color filter 23 are made different. Specifically, in the first embodiment, as shown in Fig. 16, the thickness of the first color filter 13 in the Z direction is made relatively thinner than the thickness of the second color filter 23 in the Z direction. The thickness of the second color filter 23 in the Z direction is substantially the same as those of the first color filter 13 and the second color filter 23 in the comparative example described above. This makes the color reproduction range of the second image displayed on the second image display panel 20 narrower than that of the comparative example.

[0080] 17 is a graph showing an example of the spectral transmittance of the first color filter and the second color filter in the display device according to the first embodiment. The horizontal axis in FIG. 17 indicates the wavelength, and the vertical axis indicates the transmittance of each color resist. In FIG. 17, the thick solid line indicates the transmittance of the red color resist of the second color filter 23, the thick dashed line indicates the transmittance of the green color resist of the second color filter 23, and the thick dashed line indicates the transmittance of the blue color resist of the second color filter 23. In addition, the thin solid line indicates the transmittance of the red color resist of the first color filter 13, the thin dashed line indicates the transmittance of the green color resist of the first color filter 13, and the thin dashed line indicates the transmittance of the blue color resist of the first color filter 13. The half-width of the transmittance of the green color resist of the second color filter 23 shown by the thick dashed line is narrower than the half-width of the transmittance of the green color resist of the first color filter 13 shown by the thin dashed line. The half width of the transmittance of the blue color resist of the second color filter 23 indicated by the thick dashed line is narrower than the half width of the transmittance of the blue color resist of the first color filter 13 indicated by the thin dashed line.

[0081] Fig. 18 is a graph showing an example of the transmitted light spectrum of the first color filter and the incident light spectrum of the second color filter in the display device according to the first embodiment. The horizontal axis in Fig. 18 indicates the wavelength, and the vertical axis indicates the light intensity (relative value) of the transmitted light of the first color filter when the first image display is gradation 0 for each color. In Fig. 18, the solid line indicates the spectrum of light transmitted through the red color resist, the dashed line indicates the spectrum of light transmitted through the green color resist, and the dashed line indicates the spectrum of light transmitted through the blue color resist. Note that the two-dot chain line in Fig. 18 indicates the spectrum of light incident on the second image displayed on the second image display panel 20 as a result of transmitting through the first color filter.

[0082] The light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the color resists of each color of the second color filter 23 of the second image display panel 20, respectively.

[0083] More specifically, the combined light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the red color resist of the second color filter 23 of the second image display panel 20. Moreover, the combined light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the green color resist of the second color filter 23 of the second image display panel 20. Moreover, the combined light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the blue color resist of the second color filter 23 of the second image display panel 20.

[0084] As a result, the incident light spectrum of the second image displayed on the second image display panel 20 is represented as a composite light spectrum combining the light transmitted through each color resist of the first color filter 13 of the first image display panel 10, as shown by the dotted line in Figure 18.

[0085] The color reproduction gamut of the second image displayed on the second image display panel 20 is determined by the light transmitted through each color resist of the second color filter 23. Fig. 19 is a schematic diagram showing an example of the color reproduction gamut of the second image in a state in which the second image is displayed on the second image display panel in the display device according to the first embodiment. The solid line shown in Fig. 19 indicates the color reproduction gamut of the second image transmitted through the second image display panel 20. The dashed line shown in Fig. 19 indicates the color reproduction gamut of the transmitted light of the first image display panel 10.

[0086] In the display device 1 according to the first embodiment, when the second image is displayed on the second image display panel, as shown in Fig. 19, the color reproduction range of the transmitted light of the first image display panel 10 is narrower than that of the display device according to the comparative example, but the color reproduction range of the second image displayed on the second image display panel 20 by the transmitted light of the first image display panel 10 is wider than that of the transmitted light of the first image display panel 10. In the configuration of the display device 1 according to the first embodiment, the thickness of the first color filter 13 in the Z direction is relatively thin compared to the thickness of the second color filter 23 in the Z direction, so that the luminance of the second image displayed on the second image display panel 20 can be increased. Specifically, for example, the luminance of the second image displayed on the second image display panel 20 can be about 1.3 times that of the configuration according to the comparative example.

[0087] Fig. 20 is a diagram conceptually illustrating a state in which a first image is displayed on a first image display panel in the display device according to embodiment 1. In Fig. 20, arrows indicate light passing through a red color resist CFR (first region) corresponding to a subpixel that reproduces red in the first image, a green color resist CFG (second region) corresponding to a subpixel that reproduces green in the first image, and a blue color resist CFB (third region) corresponding to a subpixel that reproduces blue in the first image.

[0088] Fig. 21 is a graph showing an example of a transmitted light spectrum of a first color filter in the display device according to embodiment 1. The horizontal axis in Fig. 21 indicates wavelength, and the vertical axis indicates the light intensity (relative value) of the transmitted light of the first color filter when the first image display is at 0 gradation for each color. In Fig. 21, the solid line indicates the spectrum of light transmitted through a red color resist, the dashed line indicates the spectrum of light transmitted through a green color resist, and the dashed-dotted line indicates the spectrum of light transmitted through a blue color resist. The peak value of each spectrum shown in Fig. 21 corresponds to the gradation value of each sub-pixel that reproduces each color in the second image.

[0089] Light emitted from a backlight 30 shown in FIG.

[0090] The light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the color resists of each color of the second color filter 23 of the second image display panel 20, respectively.

[0091] More specifically, light transmitted through the red color resist of the first color filter 13 of the first image display panel 10 is incident on each color resist of the second color filter 23 of the second image display panel 20. Light transmitted through the green color resist of the first color filter 13 of the first image display panel 10 is incident on each color resist of the second color filter 23 of the second image display panel 20. Light transmitted through the blue color resist of the first color filter 13 of the first image display panel 10 is incident on each color resist of the second color filter 23 of the second image display panel 20.

[0092] Specifically, for example, when red is displayed on the first image display panel 10, light that has passed through the red color register of the first image display panel 10 enters the second image display panel 20. The red light that has entered the second image display panel 20 passes through each color register of the second image display panel 20, and a color synthesized by the lights that have passed through each color register of the second image display panel 20 is visually recognized by an observer.

[0093] Furthermore, for example, when green is displayed on the first image display panel 10, light that has passed through the green color register of the first image display panel 10 enters the second image display panel 20. The green light that has entered the second image display panel 20 passes through each color register of the second image display panel 20, and a color synthesized by the lights that have passed through each color register of the second image display panel 20 is visually recognized by an observer.

[0094] Furthermore, for example, when blue is displayed on the first image display panel 10, light that has passed through the blue color register of the first image display panel 10 enters the second image display panel 20. The blue light that has entered the second image display panel 20 passes through each color register of the second image display panel 20, and a color synthesized by the lights that have passed through each color register of the second image display panel 20 is visually recognized by an observer.

[0095] The color reproduction gamut of the first image displayed on the first image display panel 10 is determined by the light transmitted through each color resist of the second color filter 23. Fig. 22 is a schematic diagram showing an example of the color reproduction gamut of the first image in a state where the first image is displayed on the first image display panel in the display device according to the first embodiment. The solid line shown in Fig. 22 indicates the color reproduction gamut of the first image transmitted through the second image display panel 20. The dashed line shown in Fig. 22 indicates the color reproduction gamut of the first image transmitted through the first image display panel 10.

[0096] In the display device 1 according to the first embodiment, when the first image is displayed on the first image display panel, as shown in FIG. 22, the color reproduction range of the first image transmitted through the second image display panel 20 is not significantly different from the color reproduction range of the first image transmitted through the first image display panel 10, and is narrower than the configuration of the display device according to the comparative example. Therefore, the color reproduction range of the first image shown by the solid line in FIG. 22 is narrower than the color reproduction range of the second image shown by the solid line in FIG. 19. Even in this case, the luminance of the first image displayed on the first image display panel 10 can be increased by making the thickness of the first color filter 13 in the Z direction relatively thinner than the thickness of the second color filter 23 in the Z direction. Specifically, for example, the luminance of the first image displayed on the first image display panel 10 can be about 1.3 times that of the configuration according to the comparative example.

[0097] As described above, in the display device 1 according to the first embodiment, the thickness of the first color filter 13 in the Z direction is made relatively smaller than the thickness of the second color filter 23 in the Z direction. This makes it possible to increase the amount of light transmitted through the first color filter 13 and suppress a decrease in the amount of light transmitted through the display device 1.

[0098] (Embodiment 2) Fig. 23 is a diagram conceptually illustrating a state in which a second image is displayed on a second image display panel in the display device according to embodiment 2. In Fig. 23, arrows indicate light passing through a red color resist CFR (first region) corresponding to a subpixel that reproduces red in the second image, a green color resist CFG (second region) corresponding to a subpixel that reproduces green in the second image, and a blue color resist CFB (third region) corresponding to a subpixel that reproduces blue in the second image.

[0099] In the display device 1a according to the second embodiment, the color densities of the first color filter 13 and the second color filter 23 are made different from each other, as in the first embodiment. Specifically, in the second embodiment, as shown in FIG. 23, the thickness of the second color filter 23 in the Z direction is made relatively thinner than the thickness of the first color filter 13 in the Z direction. The thickness of the first color filter 13 in the Z direction is substantially the same as those of the first color filter 13 and the second color filter 23 in the comparative example described above. This results in a narrower color reproduction range of the first image displayed on the first image display panel 10 than in the comparative example.

[0100] Fig. 24 is a graph showing an example of the spectral transmittance of the first color filter and the second color filter in the display device according to the second embodiment. The horizontal axis in Fig. 24 indicates the wavelength, and the vertical axis indicates the transmittance of each color resist. In Fig. 24, the thick solid line indicates the transmittance of the red color resist of the first color filter 13, the thick dashed line indicates the transmittance of the green color resist of the first color filter 13, and the thick dashed line indicates the transmittance of the blue color resist of the first color filter 13. In addition, the thin solid line indicates the transmittance of the red color resist of the second color filter 23, the thin dashed line indicates the transmittance of the green color resist of the second color filter 23, and the thin dashed line indicates the transmittance of the blue color resist of the second color filter 23.

[0101] Fig. 25 is a graph showing an example of the transmitted light spectrum of the first color filter and the incident light spectrum of the second color filter in the display device according to the second embodiment. The horizontal axis in Fig. 25 indicates the wavelength, and the vertical axis indicates the light intensity (relative value) of the transmitted light of the first color filter. In Fig. 25, the solid line indicates the spectrum of light transmitted through the red color resist, the dashed line indicates the spectrum of light transmitted through the green color resist, and the dashed line indicates the spectrum of light transmitted through the blue color resist. Note that the two-dot chain line in Fig. 25 indicates the spectrum of light that is transmitted through the first color filter and is incident on the second image displayed on the second image display panel 20.

[0102] The light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the color resists of each color of the second color filter 23 of the second image display panel 20, respectively.

[0103] More specifically, the combined light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the red color resist of the second color filter 23 of the second image display panel 20. Moreover, the combined light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the green color resist of the second color filter 23 of the second image display panel 20. Moreover, the combined light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the blue color resist of the second color filter 23 of the second image display panel 20.

[0104] As a result, the incident light spectrum of the second image displayed on the second image display panel 20 is represented as a composite light spectrum combining the light transmitted through each color resist of the first color filter 13 of the first image display panel 10, as shown by the dotted line in Figure 25.

[0105] The color reproduction gamut of the second image displayed on the second image display panel 20 is determined by the light transmitted through each color resist of the second color filter 23. Fig. 26 is a schematic diagram showing an example of the color reproduction gamut of the second image in a state where the second image is displayed on the second image display panel in the display device according to the second embodiment. The dashed dotted line shown in Fig. 26 indicates the color reproduction gamut of the second image transmitted through the second image display panel 20. The dotted line shown in Fig. 26 indicates the color reproduction gamut of the transmitted light of the first image display panel 10.

[0106] In the display device 1a according to the second embodiment, when the second image is displayed on the second image display panel, as shown in FIG. 26, the color reproduction range of the transmitted light of the first image display panel 10 is narrower than that of the display device according to the comparative example, but the color reproduction range of the second image displayed on the second image display panel 20 by the transmitted light of the first image display panel 10 is wider than that of the transmitted light of the first image display panel 10, as in the display device 1 according to the first embodiment. In the configuration of the display device 1a according to the second embodiment, the thickness of the second color filter 23 in the Z direction is relatively thin compared to the thickness of the first color filter 13 in the Z direction, so that the luminance of the second image displayed on the second image display panel 20 can be increased. Specifically, for example, the luminance of the second image displayed on the second image display panel 20 can be about 1.2 times that of the configuration according to the comparative example.

[0107] Fig. 27 is a diagram conceptually illustrating a state in which a first image is displayed on a first image display panel in a display device according to embodiment 2. In Fig. 27, arrows indicate light passing through a red color resist CFR (first region) corresponding to a subpixel that reproduces red in the first image, a green color resist CFG (second region) corresponding to a subpixel that reproduces green in the first image, and a blue color resist CFB (third region) corresponding to a subpixel that reproduces blue in the first image.

[0108] Fig. 28 is a graph showing an example of a transmitted light spectrum of a first color filter in the display device according to embodiment 2. The horizontal axis in Fig. 28 indicates wavelength, and the vertical axis indicates light intensity (relative value) of transmitted light through the first color filter. In Fig. 28, the solid line indicates the spectrum of light transmitted through a red color resist, the dashed line indicates the spectrum of light transmitted through a green color resist, and the dashed-dotted line indicates the spectrum of light transmitted through a blue color resist. The peak value of each spectrum shown in Fig. 28 corresponds to the gradation value of each sub-pixel that reproduces each color in the second image.

[0109] Light emitted from a backlight 30 shown in FIG.

[0110] The light transmitted through the color resists of each color of the first color filter 13 of the first image display panel 10 is incident on the color resists of each color of the second color filter 23 of the second image display panel 20, respectively.

[0111] More specifically, light transmitted through the red color resist of the first color filter 13 of the first image display panel 10 is incident on each color resist of the second color filter 23 of the second image display panel 20. Light transmitted through the green color resist of the first color filter 13 of the first image display panel 10 is incident on each color resist of the second color filter 23 of the second image display panel 20. Light transmitted through the blue color resist of the first color filter 13 of the first image display panel 10 is incident on each color resist of the second color filter 23 of the second image display panel 20.

[0112] Specifically, for example, when red is displayed on the first image display panel 10, light that has passed through the red color register of the first image display panel 10 enters the second image display panel 20. The red light that has entered the second image display panel 20 passes through each color register of the second image display panel 20, and a color synthesized by the lights that have passed through each color register of the second image display panel 20 is visually recognized by an observer.

[0113] Furthermore, for example, when green is displayed on the first image display panel 10, light that has passed through the green color register of the first image display panel 10 enters the second image display panel 20. The green light that has entered the second image display panel 20 passes through each color register of the second image display panel 20, and a color synthesized by the lights that have passed through each color register of the second image display panel 20 is visually recognized by an observer.

[0114] Furthermore, for example, when blue is displayed on the first image display panel 10, light that has passed through the blue color register of the first image display panel 10 enters the second image display panel 20. The blue light that has entered the second image display panel 20 passes through each color register of the second image display panel 20, and a color synthesized by the lights that have passed through each color register of the second image display panel 20 is visually recognized by an observer.

[0115] The color reproduction gamut of the first image displayed on the first image display panel 10 is determined by the light transmitted through each color resist of the second color filter 23. Fig. 29 is a schematic diagram showing an example of the color reproduction gamut of the first image in a state where the first image is displayed on the first image display panel in the display device according to the second embodiment. The dashed and dotted line shown in Fig. 29 indicates the color reproduction gamut of the first image transmitted through the second image display panel 20. The dotted line shown in Fig. 29 indicates the color reproduction gamut of the first image transmitted through the first image display panel 10.

[0116] In the display device 1a according to the second embodiment, when the first image is displayed on the first image display panel, as shown in FIG. 29, the color reproduction range of the first image transmitted through the second image display panel 20 is not significantly different from the color reproduction range of the first image transmitted through the first image display panel 10, and is narrower than the configuration of the display device according to the comparative example, as in the display device 1 according to the first embodiment. Therefore, the color reproduction range of the second image shown by the dashed line in FIG. 26 is narrower than the color reproduction range of the first image shown by the dashed line in FIG. 29. Even in this case, the luminance of the first image displayed on the first image display panel 10 can be increased by making the thickness of the second color filter 23 in the Z direction relatively thinner than the thickness of the first color filter 13 in the Z direction. Specifically, for example, the luminance of the first image displayed on the first image display panel 10 can be about 1.2 times that of the configuration according to the comparative example.

[0117] As described above, in the display device 1a according to the second embodiment, the thickness in the Z direction of the second color filter 23 is made relatively thinner than the thickness in the Z direction of the first color filter 13. This makes it possible to increase the amount of light transmitted through the second color filter 23 and suppress a decrease in the amount of light transmitted through the display device 1a.

[0118] Fig. 30 is a first schematic diagram comparing the color gamut of the display device according to embodiment 1 with the color gamut of the display device according to embodiment 2. In the first schematic diagram shown in Fig. 30, the color gamuts when the second image is displayed on the second image display panel 20 are compared.

[0119] The solid line in Fig. 30 indicates the color reproduction gamut of the display device 1 according to embodiment 1 (the color reproduction gamut shown by the solid line in Fig. 19). The color reproduction gamut of the display device 1 according to embodiment 1 is roughly the same as the color reproduction gamut of the display device according to the comparative example (the color reproduction gamut shown by the solid line in Fig. 12).

[0120] The dashed-dotted line in FIG. 30 indicates the color reproduction range of the display device 1a according to the second embodiment (the color reproduction range indicated by the dashed-dotted line in FIG. 26).

[0121] As shown in Figure 30, when the second image is displayed on the second image display panel 20, the color reproduction range of the display device 1 of embodiment 1, shown by the solid line, is relatively wider than the color reproduction range of the display device 1a of embodiment 2, shown by the dotted line.

[0122] Fig. 31 is a second schematic diagram comparing the color gamut of the display device according to embodiment 1 with the color gamut of the display device according to embodiment 2. In the second schematic diagram shown in Fig. 31, the color gamuts when the first image is displayed on the first image display panel 10 are compared.

[0123] The solid line in FIG. 31 indicates the color reproduction range of the display device 1 according to the first embodiment (the color reproduction range indicated by the solid line in FIG. 22).

[0124] The dashed-dotted line in Fig. 31 indicates the color reproduction gamut of the display device 1a according to embodiment 2 (the color reproduction gamut shown by the dashed-dotted line in Fig. 29). The color reproduction gamut of the display device 1a according to embodiment 2 is roughly the same as the color reproduction gamut of the display device according to the comparative example (the color reproduction gamut shown by the solid line in Fig. 15).

[0125] As shown in Figure 31, when the first image is displayed on the first image display panel, the color reproduction range of the display device 1 of embodiment 1, shown by the solid line, is relatively narrower than the color reproduction range of the display device 1a of embodiment 2, shown by the dotted line.

[0126] 1, the virtual image VIR of the first image displayed on the first image display panel 10 is viewed by the observer OB at a position farther away in the direction indicated by the dashed arrow in Fig. 1 than the virtual image VIF of the second image displayed on the second image display panel 20. In other words, the virtual image VIR of the first image displayed on the first image display panel 10 is viewed as being behind the virtual image VIF of the second image displayed on the second image display panel 20.

[0127] In such an embodiment of the HUD 100, it is desirable that the virtual image VIF of the second image visually recognized in the forward direction has high color reproducibility. Therefore, as the configuration of the display device applied to the HUD 100 of the embodiment shown in Fig. 1, it is desirable to apply the configuration of the first embodiment in which the first color filter 13 is made relatively thinner than the second color filter 23 and the color reproduction range of the first image by the first color filter 13 is narrowed, thereby suppressing a decrease in the amount of light transmitted through the display device 1.

[0128] In the above-described embodiments, the thickness of the first color filter 13 is different from that of the second color filter 23. Alternatively, the thickness of the red color resist (first region) of the first color filter 13 may be different from that of the red color resist (first region) of the second color filter 23. Alternatively, the thickness of the green color resist (second region) of the first color filter 13 may be different from that of the green color resist (second region) of the second color filter 23. Alternatively, the thickness of the blue color resist (third region) of the first color filter 13 may be different from that of the blue color resist (third region) of the second color filter 23. The transmission colors of the color resists provided in the first color filter 13 and the second color filter 23 are not limited to red (R), green (G), and blue (B), and may include, for example, white (W). Furthermore, the first color filter 13 and the second color filter 23 may be color filters of complementary colors such as white (W), cyan (C), magenta (M), yellow (Y), and green (G).

[0129] Although the preferred embodiment of the present disclosure has been described above, the present disclosure is not limited to such an embodiment. The contents disclosed in the embodiment are merely examples, and various modifications are possible within the scope of the present disclosure. For example, appropriate modifications made within the scope of the present disclosure naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0130] 1,1a Display device 2. Magnification Optical System 10 First image display panel 11 First LCD panel 12 First polarizing plate 13 First color filter 20 Second image display panel 21 Second LCD panel 22 Second polarizing plate 23 Second Color Filter 30 Backlight 100 HUD (Head-Up Display) COMP_OBJ Composite Object EB, EB1, EB2 Eye Box FG Translucent material L light O Lens OB Observer OBJ1 First object OBJ2 Second object S gap VI Virtual Image VIF Virtual image (second image) VIR Virtual image (first image)

Claims

1. Backlight and a first image display panel on which direct light from the backlight is incident; a second image display panel disposed with a gap between it and the first image display panel, and into which transmitted light of the first image display panel is incident; Equipped with The first image display panel includes: a first polarizing plate that transmits light polarized in a first direction and blocks light polarized in a direction different from the first direction; a first color filter provided at least between the first polarizing plate and the second image display panel; Including, The second image display panel includes: a second polarizing plate that transmits light polarized in a second direction different from the first direction and blocks light polarized in a direction different from the second direction; a second color filter provided at least between the second polarizing plate and the first image display panel; Including, the first color filter and the second color filter have different thicknesses, No other polarizing plate is provided between the first image display panel and the second image display panel. Display device.

2. The first color filter is relatively thin relative to the second color filter. The display device according to claim 1 .

3. the second color filter is relatively thin with respect to the first color filter; The display device according to claim 1 .

4. The first color filter and the second color filter are a first region that transmits a first light and attenuates light having a wavelength other than the first light; a second region that transmits a second light having a wavelength different from the first light and attenuates light having a wavelength other than the second light; a third region that transmits a third light having a wavelength different from the first light and the second light and attenuates light having a wavelength other than the third light; having The display device according to claim 1 .

5. a thickness of the first region of the first color filter is relatively smaller than a thickness of the first region of the second color filter; The display device according to claim 4.

6. a thickness of the second region of the first color filter is relatively smaller than a thickness of the second region of the second color filter; The display device according to claim 4.

7. a thickness of the third region of the first color filter is relatively smaller than a thickness of the third region of the second color filter; The display device according to claim 4.

8. a thickness of the first region of the second color filter is relatively thin compared to a thickness of the first region of the first color filter; The display device according to claim 4.

9. The thickness of the second region of the second color filter is relatively thin compared to the thickness of the second region of the first color filter. The display device according to claim 4.

10. a thickness of the third region of the second color filter is relatively smaller than a thickness of the third region of the first color filter; The display device according to claim 4.

11. an image output region of the first image display panel and an image output region of the second image display panel overlap in a line of sight of a viewer; The display device according to claim 1 .

12. a distance from a viewpoint of a viewer to a first image displayed on the first image display panel is greater than a distance from a viewpoint of a viewer to a second image displayed on the second image display panel; The display device according to claim 11.

13. The first image and the second image overlap in the line of sight of an observer. The display device according to claim 12.

14. a first object displayed on the first image display panel and a second object displayed on the second image display panel overlap each other in a line of sight of a viewer to form one composite object; The display device according to claim 13.

15. A head-up display in which an image reflected by a translucent member that transmits and reflects incident light is superimposed on a real image transmitted through the translucent member, and the image reflected by the translucent member is visually recognized by an observer as a virtual image, A display device according to any one of claims 11 to 14, a magnifying optical system that magnifies an image displayed on the display device and projects the magnified image onto the light-transmitting member; Equipped with Head-up display.

Images