JP7501293B2 - Display device - Google Patents

Description

This disclosure relates to a display device.

A technology is known in which a laser beam generated by a laser diode is irradiated onto a YAG laser rod, and this YAG laser beam is incident on a nonlinear optical material to generate a second harmonic, which is then magnified by a concave lens and becomes the light source for a display unit consisting of a liquid crystal display.

Japanese Patent Application Laid-Open No. 2-103586

However, in the conventional techniques described above, it is difficult to diffuse light such as laser light appropriately using an optical system and then make the light uniformly incident on a display screen. In other words, it is difficult to make light such as laser light spread uniformly using an optical system so that it can be used as a surface light source for a display screen.
Therefore, an object of the present disclosure is to diffuse light appropriately using an optical system and then allow the light to be incident on a display screen relatively uniformly.

In one aspect, the present invention includes a light source unit (2) that emits light;
an optical system (4) disposed on an optical path of light emitted from the light source unit;
a display screen (6) that generates display light based on the light emitted from the optical system;
The optical system includes a fly-eye lens (42) on which light parallelized with respect to an optical axis (I ₀ ) of the optical system is incident,
the display screen is disposed in a tilted manner with respect to an optical axis of the optical system;
A display device (1) is provided, wherein the shape of the fly's eye lens is formed asymmetrically.

According to the present disclosure, it is possible to appropriately diffuse light using an optical system and then allow the light to be incident on a display screen relatively uniformly.

1 is a diagram showing a head-up display mounted on a vehicle as viewed from the side of the vehicle. FIG. FIG. 1 is a schematic diagram illustrating a configuration of a display device. FIG. 4 is an explanatory diagram of the inclination of a liquid crystal panel. 4A and 4B are schematic diagrams illustrating a diffusion member of a rotating diffusion unit. 5A and 5B are schematic diagrams showing the concave-convex pitch of the diffusion member of the rotary diffusion section; FIG. 2 is an explanatory diagram of a collimator lens. 1 is a diagram (part 1) illustrating the characteristics of a collimator lens according to the present embodiment. FIG. FIG. 2 is a diagram illustrating the characteristics of the collimator lens of the present embodiment (part 2). 10 is a diagram (part 3) illustrating the characteristics of the collimator lens of the present embodiment. FIG. 1 is a diagram (part 1) illustrating the characteristics of a collimator lens according to a comparative example; FIG. 11 is a diagram (part 2) illustrating the characteristics of a collimator lens according to a comparative example. FIG. 2 is a plan view illustrating a schematic relationship between a fly's eye lens and a liquid crystal panel when viewed along the x-axis. FIG. 2 is a plan view illustrating a schematic relationship between a fly's eye lens and a liquid crystal panel when viewed along the y-axis.

Each embodiment will be described in detail below with reference to the attached drawings.

[Head-up display configuration]
FIG. 1 is a diagram showing a state in which a head-up display HUD is mounted on a vehicle VC (an example of a moving body) as viewed from the side of the vehicle. FIG. 2A is a schematic diagram showing a configuration of a display device 1. FIG. 2B is an explanatory diagram of the inclination of a liquid crystal panel. FIG. 3A and FIG. 3B are schematic diagrams showing the uneven pitch of a diffusion member 31 of a rotating diffusion unit 3. FIG. 3A shows a plan view of the diffusion member 31, and FIG. 3B shows a cross-sectional view (cross-sectional view along line A-A) along the radial direction of the diffusion member 31. In the cross-sectional view shown in FIG. 3B, the X1 side in the X direction corresponds to the inner periphery side, and the X2 side corresponds to the outer periphery side.

In the head-up display HUD, as shown in FIG. 1, when display light is irradiated onto the windshield WS, the driver of the vehicle VC sees a display image (virtual image display) VI obtained by said irradiation, ahead of the windshield WS. This allows the driver to visually recognize the display image VI superimposed on the scenery ahead. Therefore, the driver can grasp vehicle information, etc. with less eye movement compared to when looking at the meters in the instrument panel 9, improving convenience and safety.

The head-up display HUD includes a display device 1 and a hologram HOE.

The display device 1 projects light relating to an image (display light) toward a hologram HOE on the windshield WS located in front of the driver. The hologram HOE on the windshield WS reflects the light relating to the image into the driver's eyebox. In this case, when viewed from a viewpoint related to the eyebox, a display image VI based on the light relating to the image is formed in front of the driver's field of vision.

The hologram HOE may be formed of, for example, a photopolymer. The types of hologram HOE are reflection type, phase change type, and volume type. The hologram HOE may be formed using a hologram film having a thickness of several microns. In the hologram HOE, the interference fringes are recorded, for example, in the form of a change in refractive index. That is, in the hologram HOE, the interference fringes are stored in layers as a refractive index distribution inside the material. In this embodiment, the hologram HOE records interference fringes related to each of the RGB wavelengths in response to the three colors of laser light. In this case, a hologram layer may be created for each of the interference fringes related to the RGB wavelengths, and the hologram layers related to each may be laminated to form a laminated hologram HOE. Alternatively, a multiplexed hologram HOE in which RGB interference fringes are recorded by overlapping them may be realized. In addition, any laser interference exposure device may be used for recording (exposing) such interference fringes.

As shown in FIG. 2A, the display device 1 includes a light source unit 2, a rotating diffusion unit 3, a lens group 4 onto which the laser light that has passed through the rotating diffusion unit 3 is incident, a liquid crystal panel 6, and a control unit 7.

The light source unit 2 emits laser light (red laser light R, green laser light G, and blue laser light B). In this embodiment, since it is possible to emit laser light of these three colors, it is possible to generate a full-color display image VI. However, in a modified example, the variation of colors that can be displayed may be small.

The rotating diffusion unit 3 diffuses the laser light emitted from the light source unit 2. The rotating diffusion unit 3 has the function of multiplexing the laser light to reduce speckle.

As shown in FIG. 2A, the rotating diffusion unit 3 includes a disk-shaped diffusion member 31, a rotary motor 32 that rotates the diffusion member 31 around the circular center of the diffusion member 31 as the rotation axis, and a moving motor 33 that moves the incidence position of the laser light on the diffusion member 31 in the radial direction of the diffusion member 31 by moving the diffusion member 31 and the rotary motor 32 in a direction perpendicular to the optical path of the laser light.

As shown in FIG. 3B, the diffusion member 31 has an uneven pattern including a large number of unevennesses on at least one surface. This uneven pattern is formed so that the uneven pitch in the circumferential direction is large on the inner circumference side (smaller rotation radius side) and the uneven pitch in the circumferential direction is small on the outer circumference side (larger rotation radius side). Such a diffusion member 31 diffuses the incident laser light even when it is not rotating, but when it is rotating due to the rotary motor 32, the laser light is multiplexed to reduce speckles. In addition, if the number of rotations of the diffusion member 31 is increased, the number of times the laser light crosses the unevenness in the circumferential direction (number of times per unit time) increases, so the number of multiplexings can be increased to enhance the speckle reduction effect.

Moving the incidence position of the laser light onto the rotating diffusion member 31 toward the outer periphery of the diffusion member 31 increases the circumferential distance of the laser light incidence position, and the number of times the laser light crosses the unevenness during one rotation of the diffusion member 31 increases, so the multiplexing number can be increased to further enhance the speckle reduction effect.Moving the incidence position of the laser light onto the rotating diffusion member 31 toward the outer periphery of the diffusion member 31 reduces the unevenness pitch of the laser light incidence position, and the number of times the laser light crosses the unevenness increases, so the multiplexing number can be increased to further enhance the speckle reduction effect.

The lens group 4 includes a collimator lens 41, a fly-eye lens 42, a condenser lens 43, a field lens 44, a lenticular lens 45, and a screen diffuser 46.

The collimator lens 41 receives the laser light (diffused light) from the rotating diffusion unit 3. The collimator lens 41 has the function of homogenizing the diffused light emitted from the rotating diffusion unit 3 while converting it into parallel light. The configuration of the collimator lens 41 will be described in detail later.

The fly-eye lens 42 receives the laser light (parallel light) from the collimator lens 41. The fly-eye lens 42 has a function of illuminating the liquid crystal panel 6 uniformly and in accordance with the screen shape (e.g., rectangular) regardless of the distribution of the incident light from the collimator lens 41. The configuration of the fly-eye lens 42 will be described in detail later.

The condenser lens 43 has a function of, for example, superimposing the light emitted from multiple portions of the fly-eye lens 42 (multiple convex portions 4220 described below) on the screen of the liquid crystal panel 6. The condenser lens 43 may be configured to cooperate with the fly-eye lens 42 to homogenize the distribution of the light incident on the screen of the liquid crystal panel 6.

The field lens 44 has the function of, for example, superimposing the light emitted from the screen of the liquid crystal panel 6 on the eyebox.

The lenticular lens 45 has a function of adjusting the diffusion angle, for example, when the diffusion angle of the light generated by the fly-eye lens 42 is insufficient. The lenticular lens 45 may be configured to expand the range of the eyebox while working with the collimator lens 41 described above to homogenize the luminance distribution in the eyebox (increase the uniformity). The lenticular lens 45 may be provided between the field lens 44 and the screen diffusion plate 46.

The screen diffuser 46 has the function of reducing brightness unevenness that may occur due to, for example, the liquid crystal panel 6 and the lenticular lens 45.

The configuration of the lens group 4 is not limited to the configuration shown in FIG. 2A. For example, in a modified example, the lenticular lens 45 may be omitted, or other optical systems may be added.

The liquid crystal panel 6 forms an image for the display image VI using the laser light that has passed through the lens group 4 as a backlight. The display light emitted from the liquid crystal panel 6 is projected onto the hologram HOE as described above. Note that another optical system (not shown) may be disposed between the liquid crystal panel 6 and the hologram HOE.

As shown in FIG. 2B, the liquid crystal panel 6 is arranged in such a manner that the panel surface (incident surface) is inclined with respect to the optical axis I0 of the lens group 4 (note that the inclination is not shown in FIG. 2A). Specifically, the normal direction _V0 of the liquid crystal panel 6 forms an angle θ (> ₀ ) with respect to the optical axis _I0 of the lens group 4. Here, as an example, the normal direction _V0 and the optical axis _I0 extend in the same plane (a plane parallel to the paper surface of FIG. 2B). Note that the inclination direction of the liquid crystal panel 6 is arbitrary, and for example, in order to reduce the influence of the incidence of sunlight, the vertical direction to the panel surface may be, for example, a direction toward the case (not shown). Note that the field lens 44, the lenticular lens 45, and the screen diffusion plate 46 may also be inclined in the same manner as the liquid crystal panel 6.

The control unit 7 includes, for example, a microcomputer, and controls the rotation diffusion unit 3 and the liquid crystal panel 6.

[Collimator lens]
Next, a preferred example of the collimator lens 41 will be described in detail.

Figure 4 is an explanatory diagram of the collimator lens 41. In Figure 4, the manner in which light incident on the collimator lens 41 from a specific position P of the rotating diffusion section 3 is emitted from the collimator lens 41 is shown diagrammatically by a light ray line L400. In Figure 4, the Z direction parallel to the optical axis is defined, and the Z1 side and the Z2 side are defined.

The collimator lens 41 shown in FIG. 4 includes a curved surface 410 on the incident surface 41A side and a curved surface 412 on the exit surface 41B side.

The curved surface 410 is formed in a concave shape on the Z2 side. The curved surface 412 is formed in a convex shape on the Z2 side. The curved surfaces 410 and 412 are, for example, spherical surfaces, but may be aspherical surfaces. However, from the viewpoint of workability, it is preferable that the curved surfaces 410 and 412 are spherical surfaces.

The curved surface 410 is shaped to match the diffusion angle α of the laser light emitted from the rotating diffusion unit 3. In other words, the curved surface 410 is formed to cover the entire spread based on the diffusion angle α (e.g., 80%, preferably 90%). The value of the diffusion angle α can be obtained, for example, by displaying the half value of the central illuminance in full angles.

Here, from the viewpoint of reducing speckle, it is preferable to make the diffusion angle α of the laser light from the rotating diffusion unit 3 as wide as possible. It is preferably in the range of 20 degrees to 40 degrees. In this case, the manufacturing difficulty of the collimator lens 41 does not become too high, and it is possible to appropriately achieve both speckle reduction and manufacturability of the collimator lens 41.

The curved surface 410 is preferably shaped so that the angular density of the light immediately after entering from the rotating diffusion unit 3 is approximately uniform. The angular density of light correlates with the amount of light (intensity) for each traveling direction (e.g., the angle of the traveling direction with respect to the optical axis _I0 ) of the light entering the collimator lens 41 through the curved surface 410 as shown in Fig. 4. By making the angular density of light uniform, the spread of the laser light diffused and entering from the rotating diffusion unit 3 can be made uniform.

The curved surface 412 is shaped so that the light emitted from the curved surface 412 is collimated (i.e., parallel to the Z direction).

In this way, the collimator lens 41 can spread the diffused laser light entering from the rotating diffusion section 3 more uniformly on the curved surface 410 on the entrance side, while collimating it on the curved surface 412 on the exit side.

Next, the effect of the collimator lens 41 of this embodiment will be further explained with reference to Figures 5A to 6B.

5A to 5C are explanatory diagrams of the characteristics of the collimator lens 41 of this embodiment. FIG. 5A is a contour diagram showing the intensity characteristics of the light emitted from the collimator lens 41 when viewed along the optical axis of the collimator lens 41. In FIG. 5A, the region I1 indicates an area where the intensity is equal to or greater than a certain value β1, the region I2 indicates an area where the intensity is equal to or greater than a certain value β2, and the region I3 indicates an area where the intensity is equal to or greater than a certain value β3, where β1>β2>β3. FIG. 5B is a diagram showing the intensity characteristics L500 of the light emitted from the collimator lens 41 along a straight line perpendicular to the optical axis of the collimator lens 41 and passing through the optical axis of the collimator lens 41. FIG. 5C is a diagram showing other characteristics L501 and L502 superimposed on the characteristics shown in FIG. 5B, where the other characteristic L501 indicates the intensity characteristics of the light immediately before entering the collimator lens 41 (the intensity characteristics of the light emitted from the rotating diffusion unit 3), and the other characteristic L502 indicates the intensity characteristics of the light emitted from the light source unit 2. 5B and 5C, the origin 0 of the horizontal axis corresponds to the optical axis of the collimator lens 41 (=optical axis I ₀ ), and the horizontal axis represents the radial distance centered on the optical axis of the collimator lens 41 .

The intensity characteristics of the light emitted from the light source unit 2 are the same as those of a point light source, and as shown by characteristic L502 in Figure 5C, a local peak occurs around the position of the optical axis of the collimator lens 41.

In this embodiment, the rotating diffusion unit 3 is provided, and the light emitted from the light source unit 2 passes through the rotating diffusion unit 3, so that the characteristic L502 is converted to the characteristic L501 as shown in FIG. 5C. In other words, the intensity distribution is made uniform along the radial direction.

In this embodiment, a collimator lens 41 having a curved surface 410 on the incident side is provided on the exit side of the rotating diffusion unit 3, so that the characteristic L501 is converted to a characteristic L500 as shown in FIG. 5C. That is, the curved surface 410 of the incident surface 41A is configured so that the intensity distribution of the laser light in the radial direction centered on the optical axis is more uniform along the radial direction in the intensity distribution (see L500) immediately after it enters the incident surface 41A than in the intensity distribution (see L501) immediately before it enters the incident surface 41A. Note that the intensity distribution immediately after it enters the incident surface 41A is approximately the same as the intensity characteristic L500 of the light emitted from the collimator lens 41.

As shown in Figures 5B and 5C, the characteristic L500 has a so-called top hat shape, and the radial range where the intensity is equal to or greater than the reference intensity Ir is wide. The reference intensity Ir is, for example, 80% of the peak intensity. In this way, according to this embodiment, the radial range where the intensity is equal to or greater than the reference intensity Ir can be effectively widened, and as a result, the eyebox can be widened while effectively achieving uniformity of the luminance distribution in the eyebox (increased uniformity).

Figures 6A and 6B are explanatory diagrams of the characteristics of a collimator lens (not shown) according to a comparative example.

The collimator lens of the comparative example differs from the collimator lens 41 of this embodiment in that it does not have a curved surface 410 on the incident side, and the incident surface is formed by a flat surface.

In this comparative example, as shown in FIG. 6A, the range of region I1 is significantly narrower, and as shown in FIG. 6B, the intensity distribution L600 of the light emitted from the collimator lens of the comparative example is substantially the same as the intensity characteristic (see characteristic L501 in FIG. 5C) immediately before it enters the entrance surface of the collimator lens of the comparative example. In other words, the collimator lens of the comparative example collimates the light incident from the rotating diffusion section 3, but does not homogenize it sufficiently. Therefore, characteristic L600 is a Gaussian type, unlike characteristic L500 of this embodiment shown in FIGS. 5B and 5C, and the radial range where the intensity is equal to or greater than the reference intensity Ir is significantly narrower than characteristic L500 of this embodiment.

In contrast, according to this embodiment, as described above, by providing a collimator lens 41 having a curved surface 410 on the entrance side, the radial range where the intensity is equal to or greater than the reference intensity Ir can be effectively expanded compared to the comparative example. As a result, the eyebox can be expanded while effectively homogenizing the luminance distribution in the eyebox (increasing the uniformity).

[Fly-eye lens]
Next, a preferred example of the fly-eye lens 42 will be described in detail.

As described above with reference to Fig. 2B, in this embodiment, the liquid crystal panel 6 is inclined with respect to the optical axis _I0 . In such a configuration, the luminance distribution of the image (intermediate image) generated by the liquid crystal panel 6 is not uniform across the entire panel, and tends to change gradually (i.e., luminance unevenness tends to occur easily). This also applies to the case where light having an intensity distribution homogenized by the collimator lens 41 or the like is incident, as described above. Such a non-uniform luminance distribution produces luminance unevenness in the display image VI.

In this embodiment, the fly-eye lens 42 is configured to reduce such changes in the luminance distribution and to homogenize the luminance distribution of the image generated by the liquid crystal panel 6. Specifically, the shape of the fly-eye lens 42 is formed asymmetrically.

In the following, tilt and asymmetry will be described based on a coordinate system (see FIG. 2B) in which the direction of the optical axis _I0 of the lens group 4 is the z-axis, the coordinate axis perpendicular to the z-axis is the y-axis, and the coordinate axis perpendicular to the z-axis and the y-axis is the x-axis. Note that the "x" in the xyz coordinate system shown in FIG. 2B and the like is distinguished from the "X" in FIG. 3B, which is written in capital letters.

Fig. 7A is a plan view that shows a schematic relationship between the fly-eye lens 42 and the liquid crystal panel 6 when viewed along the x-axis, and Fig. 7B is a plan view that shows a schematic relationship between the fly-eye lens 42 and the liquid crystal panel 6 when viewed along the y-axis. Note that Fig. 7A also shows the normal direction _V0 described above with reference to Fig. 2B.

As shown in FIGS. 7A and 7B, the fly-eye lens 42 has multiple convex portions 4210 on the entrance surface 421 and multiple convex portions 4220 on the exit surface 422. The number of convex portions 4210 is arbitrary, and the arrangement is also arbitrary. The same applies to the convex portions 4220. In the example shown in FIGS. 7A and 7B, the fly-eye lens 42 has a total of nine convex portions 4210 of 3×3 and a total of nine convex portions 4220 of 3×3 when viewed in the z direction. Each of the convex portions 4210 has the same shape as each other, and each of the convex portions 4220 may have the same shape as each other.

In this embodiment, as shown in FIG. 7A, when viewed along the x-axis direction, the normal direction _V0 of the liquid crystal panel 6 is inclined with respect to the z-axis, and accordingly, when viewed along the x-axis (in a cross-sectional view cut along the yz plane), the fly-eye lens 42 is asymmetric with respect to the z-axis. Such asymmetry is caused by the aspheric asymmetry of each of the convex portions 4210 and 4220. That is, as shown in FIG. 7A, the position (vertex position P1) of the convex portion 4210 with the smallest z coordinate is offset toward the positive side of the y-axis direction from the central position of the convex portion 4210 in the y-axis direction. Also, as shown in FIG. 7A, the position (vertex position P2) of the convex portion 4220 with the largest z coordinate is offset toward the negative side of the y-axis direction from the central position of the convex portion 4220 in the y-axis direction. Note that in a modified example, the opposite may be true. In other words, the position of the convex portion 4210 with the smallest z coordinate (vertex position P1) may be offset to the negative side of the y axis direction from the central position of the convex portion 4210 in the y axis direction, and the position of the convex portion 4220 with the largest z coordinate (vertex position P2) may be offset to the positive side of the y axis direction from the central position of the convex portion 4220 in the y axis direction.

The shapes of the fly-eye lens 42 may be the same for the entrance surface 421 and the exit surface 422, but preferably have a rotationally symmetric relationship as shown in FIG. 7A. Specifically, the shape of one convex portion 4210 overlaps with the shape of one convex portion 4220 when rotated 180 degrees around a rotation axis along the x-axis. With this configuration, the mold for forming the entrance surface 421 of the fly-eye lens 42 and the mold for forming the exit surface 422 of the fly-eye lens 42 can be formed by copying one from the other, making manufacturing easy.

The aspheric profile Sag (amount of sag) relating to the aspheric shape of one convex portion 4210 (and one convex portion 4220 rotationally symmetric thereto) of the fly's eye lens 42 passing through the optical axis _I0 may be based on, for example, the following equation.

ここで、ｒ_ｘ、ｒ_ｙは、ｘ軸方向、ｙ軸方向でのそれぞれの曲率半径を示し、ｃｃ_ｘ、ｃｃ_ｙ、Ａ_ｘｉ、Ａ_ｙｉは、それぞれ係数である。Ａ_ｘｉ、Ａ_ｙｉは、ｉ＝１のとき、１次の非球面係数となり、Ａ_ｘｉ、Ａ_ｙｉは、ｉ＝３のとき、３次の非球面係数となり、以下同様である。本実施例では、ｉ＝奇数のときのｙ軸に係るＡ_ｙｉを０以外の値に設定する。例えば、３次のｙ軸に係る非球面係数Ａ_ｙ３を０以外の値に設定する。これにより、上述したフライアイレンズ４２の非対称性を実現できる。非球面係数Ａ_ｙｉ等の具体的な値は、試験やシミュレーション等を介して、上述した液晶パネル６における輝度分布について必要な均一性が確保されるように適合されてよい。

Here, r _x and _ry indicate the respective radii of curvature in the x-axis direction and the y-axis direction, and cc _x , cc _y , A _xi and A _yi are coefficients. A _xi and A _yi are first-order aspheric coefficients when i=1, and A _xi and A _yi are third-order aspheric coefficients when i=3, and so on. In this embodiment, A _yi relating to the y-axis when i=odd is set to a value other than 0. For example, the third-order aspheric coefficient A _y3 relating to the y-axis is set to a value other than 0. This allows the above-mentioned asymmetry of the fly-eye lens 42 to be realized. The specific values of the aspheric coefficient A _yi and the like may be adapted through tests, simulations, etc., so that the necessary uniformity is ensured for the luminance distribution in the above-mentioned liquid crystal panel 6.

In this manner, according to the present embodiment, even if the liquid crystal panel 6 is disposed at an incline with respect to the optical axis _I0 as described above, by forming the shape of the fly-eye lens 42 asymmetrically in accordance with the inclination, it is possible to reduce the inconvenience that tends to arise when the shape of the fly-eye lens 42 is formed symmetrically (such as the non-uniformity of the luminance distribution in the liquid crystal panel 6 described above, i.e., uneven luminance).

Incidentally, the luminance distribution in the above-mentioned liquid crystal panel 6 changes depending on the inclination angle θ (see FIG. 2B, etc.) with respect to the optical axis _I0 of the liquid crystal panel 6. That is, when a symmetrical fly-eye lens is used instead of the above-mentioned fly-eye lens 42 with asymmetrical properties in the y direction, the luminance unevenness tends to increase basically as the inclination angle θ increases. Therefore, the inclination angle θ, together with the specific values of Axi, Ayi, etc., may be adapted through tests, simulations, etc. so that the required uniformity in the luminance distribution in the above-mentioned liquid crystal panel 6 is ensured.

In this embodiment, as shown in Fig. 7B, when the liquid crystal panel 6 is viewed along the y-axis direction, the normal direction _V0 is not inclined with respect to the z-axis, and therefore the shape of the fly's eye lens 42 when viewed along the y-axis direction is formed symmetrically with respect to the z-axis. However, when the liquid crystal panel 6 is viewed along the y-axis direction, the normal direction _V0 may be inclined with respect to the z-axis, and in this case, the shape of the fly's eye lens 42 when viewed along the y-axis direction may be formed asymmetrically with respect to the z-axis. For example, when using the formula 1, _Axi related to the x-axis when i = odd number may be set to a value other than 0.

In this embodiment, two or more fly-eye lenses 42 may be provided at intervals along the direction of the optical axis _I0 . In this case, the above-mentioned function can be ensured even when highly diffusive laser light is incident due to the rotating diffusion unit 3, and the size of the fly-eye lens 42 as a whole required to ensure such function (the size in the x- and y-axis directions intersecting the optical axis _I0 ) can be effectively reduced.

Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or some of the components of the above-mentioned embodiments.

For example, in the above embodiment, the liquid crystal panel 6 that forms an image using laser light as a backlight is exemplified as the display screen, but other display panels (other screens) that can use a surface light source as a backlight may be used. Also, a MEMS system using a micromirror device by MEMS (Micro Electro Mechanical Systems) technology, a LCOS (Liquid crystal on silicon) system using a reflective liquid crystal panel, a DMD (Digital Micromirror Device) system using a digital micromirror device, etc. may be used. Also, a light source that generates light other than laser light, such as an LED (Light Emitting Diode) light source, may be used. When an LED light source is used, a lens (condenser lens) that converts the LED light into parallel light may be used in addition.

REFERENCE SIGNS LIST 1 Display device 2 Light source unit 3 Rotating diffusion unit 4 Lens group 6 Liquid crystal panel 7 Control unit 9 Instrument panel 31 Diffusion member 32 Rotating motor 33 Moving motor 41 Collimator lens 41A Incident surface 41B Exit surface 42 Fly-eye lens 421 Incident surface 422 Exit surface 4210 Convex portion 4220 Convex portion 43 Condenser lens 44 Field lens 45 Lenticular lens 46 Screen diffusion plate VC Vehicle VI Display image (virtual image display)
WS Windshield

Claims (2)

A light source unit (2) that emits light;
an optical system (4) disposed on an optical path of light emitted from the light source unit;
a display screen (6) for modulating the light emitted from the optical system to generate an image;
The optical system includes a fly-eye lens (42) onto which light parallelized with respect to an optical axis (I0) of the optical system is incident,
the display screen is disposed in a tilted manner with respect to an optical axis of the optical system;
the fly-eye lens is formed asymmetrically with respect to a plane parallel to a plane including a rotation axis of the tilt of the display screen and an optical axis of the optical system;
A display device, wherein the fly-eye lens has an entrance surface (421) and an exit surface (422) formed in point symmetry. A light source unit (2) that emits light;
an optical system (4) disposed on an optical path of light emitted from the light source unit;
a display screen (6) for modulating the light emitted from the optical system to generate an image;
The optical system includes a fly-eye lens (42) onto which light parallelized with respect to an optical axis (I0) of the optical system is incident,
the display screen is disposed in a tilted manner with respect to an optical axis of the optical system;
the fly-eye lens is formed asymmetrically with respect to a plane parallel to a plane including a rotation axis of the tilt of the display screen and an optical axis of the optical system;
A display device, wherein the fly-eye lenses include two or more lenses spaced apart from each other along the optical axis of the optical system.

Images