Head-up display device

Abstract

Provided is a head-up display device capable of reducing the divergence angle of display light which has passed a cross point. A head-up display device 100 comprises: a light source that emits light beams; a liquid crystal panel that emits display light beams L upon reception of the light beams from the light source; a first mirror that reflects the display light beams L from the liquid crystal panel and causes the reflected display light beams L to cross at a cross point Cr in a crossing direction; a second mirror 12 that reflects the display light beams L reflected on the first mirror 11 and passed through the cross point Cr; and a second lenticular lens that converges the light beams from the light source and causes the display light beams L to reach the first mirror 11 in the converged state.

Description

[Technical Field]

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

[0002] For example, a head-up display device described in Patent Document 1 includes a display that emits display light, a first mirror that reflects the display light emitted by the display, and a second mirror that reflects the display light reflected by the first mirror. The first mirror causes the reflected display light to cross up and down at a crossing point before reaching the second mirror. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 198821 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in Patent Document 1, the display light emitted from the display is parallel light, so the display light diverges at a large divergence angle after passing the cross point, which requires the second mirror to have a large reflective surface.

[0005] The present disclosure has been made in consideration of the above-described circumstances, and aims to provide a head-up display device that can reduce the divergence angle of display light that has passed a cross point. [Means for solving the problem]

[0006] In order to achieve the above object, a head-up display device according to the present disclosure includes: a light source that emits light; a liquid crystal panel that receives light from the light source and emits display light; a first mirror that reflects the display light from the liquid crystal panel and crosses the reflected display light in a cross direction at a cross point; a second mirror that reflects the display light that has been reflected by the first mirror and passed through the cross point; a first optical element that converges light from the light source so that the display light reaches the first mirror in a converged state; a second optical element that substantially collimates the light emitted from the light source; a third optical element that diverges the light that has been substantially parallelized by the second optical element and then emits the diverged light to the first optical element; Equipped with. [Effects of the Invention]

[0007] According to the present disclosure, in a head-up display device, the divergence angle of display light that has passed through a cross point can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a vehicle according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic diagram of a head-up display device according to an embodiment of the present disclosure. [Figure 3] FIG. 2 is a side view of a display unit showing an optical path according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is a plan view of a display unit showing an optical path according to an embodiment of the present disclosure. [Figure 5] FIG. 10 is a side view of a display unit showing an optical path according to a modified example of the present disclosure. [Figure 6] FIG. 10 is a plan view of a display unit showing an optical path according to a modified example of the present disclosure. [Figure 7] FIG. 10 is a side view of a display unit showing an optical path according to a modified example of the present disclosure. [Figure 8] FIG. 10 is a plan view of a display unit showing an optical path according to a modified example of the present disclosure. [Figure 9] FIG. 10 is a side view of a display unit showing an optical path according to a modified example of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of a head-up display device according to the present disclosure will be described with reference to the drawings. As shown in FIG. 1, a head-up display device 100 is mounted on a vehicle 200, and projects display light L onto a windshield 201, which is a projection target member, to display a virtual image V including vehicle information so that the virtual image V can be viewed by a viewer 1.

[0010] As shown in FIG. 2, the head-up display device 100 includes a first mirror 11, a second mirror 12, a display unit 20, and a case 30. The case 30 is made of a light-shielding resin or metal and has a box shape. The case 30 houses the first mirror 11, the second mirror 12, and the display unit 20.

[0011] The case 30 includes a light-transmitting window material 31 that transmits the display light L reflected by the second mirror 12 toward the windshield 201 (see FIG. 1). The light-transmitting window material 31 is formed into a plate shape using a light-transmitting resin or glass, and is positioned so as to correspond to the windshield 201 in the height direction of the vehicle 200.

[0012] The display unit 20 emits display light L as converging light that converges toward the first mirror 11. The convergence angle α of the display light L emitted from the display unit 20 is the angle formed by the light ray at the position farthest from the optical axis center with respect to the optical axis center. The display light L emitted from the display unit 20 converges in the height direction (cross direction) of the vehicle 200 and is parallel in the width direction of the vehicle 200. The specific configuration of the display unit 20 will be described later.

[0013] 2, the first mirror 11 is a concave mirror that is curved along the height direction of the vehicle 200 and extends linearly along the width direction of the vehicle 200. The first mirror 11 reflects the display light L emitted from the display unit 20 toward the second mirror 12. The first mirror 11 reflects the display light L from the display unit 20 toward the second mirror 12 so that the light crosses the display light L at a cross point Cr in the height direction of the vehicle 200. The cross point Cr is located between the first mirror 11 and the second mirror 12 on the optical path of the display light L. The cross point Cr is located closer to the first mirror 11 than the midpoint between the first mirror 11 and the second mirror 12. The display light L converges from the first mirror 11 to the cross point Cr and diverges from the cross point Cr to the second mirror 12 at a divergence angle β. The divergence angle β is the angle formed by the light ray at the farthest position from the optical axis center of the display light L from the cross point Cr to the second mirror 12. A reflecting surface 11a of the first mirror 11 faces downward and forward of the vehicle 200.

[0014] The second mirror 12 is a concave mirror that is curved along the height direction of the vehicle 200 and extends linearly along the width direction of the vehicle 200. The second mirror 12 reflects the display light L reflected from the first mirror 11 toward the windshield 201 (see FIG. 1). The second mirror 12 reflects the display light L from the first mirror 11 toward the windshield 201 so as to diverge. A reflective surface 12a of the second mirror 12 faces upward and rearward of the vehicle 200.

[0015] Next, a specific configuration of the display unit 20 will be described. 3 and 4, the display unit 20 includes a light source substrate 21, a plurality of light sources 22, and an illumination optical system 28 that adjusts the illumination light from the light sources 22. The illumination optical system 28 adjusts the illumination light from the light sources 22. Adjusting the illumination light refers to collimating the illumination light, diffusing, scattering, or converging the illumination light. The illumination optical system 28 includes a condenser lens 23 , a first lenticular lens 24 , a second lenticular lens 25 , a diffuser 26 , and a liquid crystal panel 27 . In the following description, the direction along the optical axis of the illumination light emitted from the light source 22 is defined as the Z direction, and the directions perpendicular to the Z direction are defined as the X direction and the Y direction. The X direction and the Y direction are perpendicular to each other. In this example, the X direction is along the short direction of the first lenticular lenses 24, etc., and the Y direction is along the long direction of the first lenticular lenses 24, etc. There is a cross point Cr (see FIG. 1) where the display light L crosses on a cross plane along the X direction and the Z direction. This cross plane is along the vehicle height direction and the vehicle longitudinal direction. The light source substrate 21, condenser lens 23, first lenticular lens 24, second lenticular lens 25, diffuser 26 and liquid crystal panel 27 are arranged along the Z direction with their respective thickness directions aligned along the Z direction, and are housed in a housing tube (not shown) formed from a light-blocking resin.

[0016] The light sources 22 emit illumination light under the control of a control unit (not shown). The light sources 22 are, for example, LEDs (Light Emitting Diodes). The plurality of light sources 22 are mounted on the main surface of the light source substrate 21. The main surface of the light source substrate 21 is the surface facing the condenser lens 23 of the light source substrate 21. The plurality of light sources 22 are arranged on the main surface of the light source substrate 21 in a matrix of 2 rows x 6 columns.

[0017] The condenser lens 23 is formed in a plate shape from a light-transmitting resin or glass. The condenser lens 23 has a function of approximately collimating the rays of illumination light emitted from each light source 22 by aligning them in the Z direction. The condenser lens 23 includes a plurality of convex lens portions 23a arranged in the X and Y directions. Each of the convex lens portions 23a is formed in a biconvex lens shape. The plurality of convex lens portions 23a are arranged in a matrix of 2 rows and 6 columns corresponding to the plurality of light sources 22.

[0018] The first lenticular lens 24 is formed in a plate shape from translucent resin or glass. More specifically, the first lenticular lens 24 has an incident surface 24i on which light is incident and an exit surface 24o from which light that has passed through the first lenticular lens 24 in its thickness direction exits. The incident surface 24i of the first lenticular lens 24 is a surface facing the condenser lens 23. The exit surface 24o of the first lenticular lens 24 is a surface facing the second lenticular lens 25.

[0019] 3, a plurality of (eleven in this example) cylindrical lens portions 24a are formed on the incident surface 24i of the first lenticular lens 24. Each of the plurality of cylindrical lens portions 24a extends in a semi-cylindrical shape in the Y direction and forms a cylindrical lens array shape arranged along the X direction. The incident surface 24i of the second lens 24 has the function of diverging light in the X direction by the cylindrical lens portions 24a in order to suppress unevenness in light intensity in the X direction.

[0020] 4, a plurality of (16 in this example) cylindrical lens portions 24b are formed on the exit surface 24o of the first lenticular lens 24. Each of the plurality of cylindrical lens portions 24b extends in a semi-cylindrical shape in the X direction and forms a cylindrical lens array shape arranged along the Y direction. The exit surface 24o of the second lens 24 has the function of diverging light in the Y direction by the cylindrical lens portions 24b to suppress unevenness in light intensity in the Y direction. The cylindrical lens portions 24a and 24b are arranged in directions that intersect with each other. The divergence angle of light can be adjusted based on the pitch and curvature radius of the cylindrical lens portions 24a and 24b.

[0021] The second lenticular lens 25 is formed into a plate shape from translucent resin or glass. More specifically, the second lenticular lens 25 has an incident surface 25i onto which light is incident and an exit surface 25o from which light exits after passing through the interior of the second lenticular lens 25 in its thickness direction. The incident surface 25i of the second lenticular lens 25 faces the first lenticular lens 24. The exit surface 25o of the second lenticular lens 25 faces the diffuser 26.

[0022] As shown in Fig. 3, the incident surface 25i of the second lenticular lens 25 is formed as a curved surface (cylindrical surface) that is convexly curved along the X direction. The incident surface 25i of the second lenticular lens 25 has a function of converging the illumination light in the X direction as converging light. The radius of curvature of the exit surface 25o determines the convergence angle α of the illumination light, and therefore the display light L. The convergence angle α of the exit surface 25o is set to an angle that allows the illumination light from the exit surface 25o to pass through the liquid crystal panel 27 and reach the first mirror 11 (see Fig. 2) as converging light as display light L.

[0023] 4, the exit surface 25o of the second lenticular lens 25 is formed as a curved surface (cylindrical surface) that is concavely curved along the Y direction. The exit surface 25o of the second lenticular lens 25 has a function of diverging the illumination light in the Y direction as diverging light.

[0024] The diffuser 26 is a diverging or diffusing plate that suppresses unevenness in light intensity, and scatters the illumination light that has passed through the second lenticular lens 25 and then radiates it toward the liquid crystal panel 27 .

[0025] The liquid crystal panel 27 is a TFT (Thin Film Transistor) type liquid crystal display panel. The liquid crystal panel 27 receives illumination light that has passed through the diffuser 26 and emits display light L under the control of a control unit (not shown).

[0026] Next, the effect of the light emitted from each light source 22 will be described. 3 and 4, the illumination light emitted from each light source 22 is substantially parallelized in the X and Y directions by passing through the condenser lens 23 so that the light rays extend in the Z direction. The illumination light that has passed through the condenser lens 23 is incident on the entrance surface 24i of the first lenticular lens 24 and exits from the exit surface 24o. As shown in FIGS. 3 and 4, the first lenticular lens 24 diverges the illumination light that has passed through the condenser lens 23 in the X and Y directions by the cylindrical lens portions 24a and 24b. This reduces unevenness in light intensity in the X and Y directions.

[0027] Illumination light transmitted through the first lenticular lens 24 enters the entrance surface 25i of the second lenticular lens 25 and exits from the exit surface 25o. As shown in Fig. 3, the second lenticular lens 25 converges the illumination light in the X direction by using the convex entrance surface 25i, i.e., orients the illumination light so that it moves toward the optical axis center as it travels. Also, as shown in Fig. 4, the second lenticular lens 25 diverges the illumination light in the Y direction by using the concave exit surface 25o, i.e., orients the illumination light so that it moves away from the optical axis center as it travels.

[0028] The illumination light transmitted through the second lenticular lens 25 is scattered by the diffuser 26 and then illuminates the liquid crystal panel 27. The liquid crystal panel 27 receives the illumination light that has passed through the diffuser 26 and emits display light L. The display light L emitted from the liquid crystal panel 27 is converged in the X direction by the incident surface 25i of the second lenticular lens 25 and diverged in the Y direction by the exit surface 25o of the second lenticular lens 25. As shown in FIG. 2, the display light L converging in the X direction is reflected by the first mirror 11 and heads toward the second mirror 12 while remaining convergent. After crossing at the cross point Cr, the display light L reaches the second mirror 12 while remaining divergent. On the other hand, the display light L diverging in the Y direction is reflected by the first mirror 11 and heads toward the second mirror 12 while remaining divergent. The display light L is then reflected by the second mirror 12 toward the windshield 201 (see FIG. 1). The display light L reflected by the windshield 201 reaches the viewer 1, and the virtual image V becomes visible to the viewer 1.

[0029] (effect) According to the embodiment described above, the following effects are achieved. (1) The head-up display device 100 includes a light source 22 that emits light, a liquid crystal panel 27 that receives light from the light source 22 and emits display light L, a first mirror 11 that reflects the display light L from the liquid crystal panel 27 and causes the reflected display light L to cross in a cross direction (the height direction of the vehicle 200) at a cross point Cr, a second mirror 12 that reflects the display light L that has been reflected by the first mirror 11 and passed through the cross point Cr, and a second lenticular lens 25 that is an example of a first optical element that converges light from the light source 22, thereby causing the display light L to reach the first mirror 11 in a converged state. According to this configuration, the display light L emitted from the liquid crystal panel 27 reaches the first mirror 11 in a converged state. Therefore, the divergence angle β of the display light L after passing the cross point Cr can be reduced. This allows the size of the second mirror 12 to be reduced. A specific description will be given below. For example, in a comparative example in which the display light emitted from the liquid crystal panel is parallel light, the light path Lq located at the outer edge of the plane perpendicular to the optical axis of the display light, as indicated by the dashed line in FIG. 2, is located outside the display light L in the above configuration. Furthermore, the divergence angle θ of the display light after passing the cross point Cr in the comparative example is larger than the divergence angle β of the display light L in the above configuration. Therefore, in the comparative example, the sizes of the first mirror 11 and the second mirror 12 had to be increased in order to reflect the display light. In this regard, with the above configuration, the divergence angle β of the display light L after passing the cross point Cr is reduced, allowing the sizes of the first mirror 11 and the second mirror 12, and therefore the size of the head-up display device 100, to be reduced.

[0030] (2) The second lenticular lens 25 has a positive power and includes an entrance surface 25i, which is an example of a convex lens surface that converges the light from the light source 22. According to this configuration, the convex lens surface of the second lenticular lens 25 can converge the light from the light source 22.

[0031] (3) The head-up display device 100 includes a condenser lens 23, which is an example of a second optical element that approximately collimates the light emitted from the light source 22, and a first lenticular lens 24, which is an example of a third optical element that diverges the light that has been approximately collimated by the condenser lens 23 and then emits it to the second lenticular lens 25. According to this configuration, the light emitted from the light source 22 is substantially collimated by the condenser lens 23, and the light is diverged by the first lenticular lens 24. In this way, the light is adjusted before reaching the second lenticular lens 25.

[0032] (4) The entrance surface 24i and the exit surface 24o of the first lenticular lens 24 are each formed in the shape of a cylindrical lens array having cylindrical lens portions 24a and 24b extending in directions that intersect with each other. According to this configuration, the single first lenticular lens 24 diffuses light so that unevenness in light intensity is suppressed in two directions (for example, the X direction and the Y direction).

[0033] (5) The exit surface 25o of the second lenticular lens 25 is formed as a curved surface that is concavely curved along the Y direction. Compared to this configuration, in the configuration of the comparative example in which the entrance surface 25i is formed as a curved surface that is concavely curved along the Y direction, both ends of the entrance surface 25i of the second lenticular lens 25 in the Y direction are prevented from contacting the first lenticular lens, so there is a risk that the distance between the first lenticular lens 24 and the second lenticular lens 25 will become large. In this regard, in the above configuration, the exit surface 25o of the second lenticular lens 25 is formed as a curved surface that is concavely curved along the Y direction, so the distance between the first lenticular lens 24 and the second lenticular lens 25 can be reduced.

[0034] The present disclosure is not limited to the above-described embodiments and drawings. Modifications (including deletion of components) may be made as appropriate within the scope of the present disclosure. An example of such a modification is described below.

[0035] (Variation) In the above embodiment, the display light L crosses in the height direction of the vehicle 200, but instead of this, or in addition to this, it may cross in the width direction of the vehicle 200. In this case, the reflecting surface 11a of the first mirror 11 is formed in a concave shape that is curved along the width direction of the vehicle 200.

[0036] The configurations of the condenser lens 23, the first lenticular lens 24, and the second lenticular lens 25 in the above embodiment can be modified as appropriate. Modifications 1 to 3 will be explained below. The following explanation will focus on the differences from the above embodiment.

[0037] (Variation 1) First, Modification 1 will be described. As shown in Fig. 5, a plurality of cylindrical lens portions 24a may be formed on the exit surface 24o of the first lenticular lens 24, and as shown in Fig. 6, a plurality of cylindrical lens portions 24b may be formed on the entrance surface 24i of the first lenticular lens 24. That is, Modification 1 is configured by turning the first lenticular lens 24 inside out so that the entrance surface 24i and the exit surface 24o of the first lenticular lens 24 in the above embodiment are opposite. Even in this case, the first lenticular lens 24 can diffuse illumination light in the X direction and the Y direction, similar to the above embodiment.

[0038] (Variation 2) Next, Modification 2 will be described. As shown in Fig. 7, incident surface 25i of second lenticular lens 25 may be formed as a flat surface extending along the X and Y directions, and exit surface 25o of second lenticular lens 25 may be formed as a curved surface that is convexly curved along the X direction. In this case, exit surface 25o of second lenticular lens 25 is formed as a toroidal surface that is convexly curved along the X direction and concavely curved along the Y direction. In this configuration, exit surface 25o of second lenticular lens 25 not only converges illumination light in the X direction as converging light like incident surface 25i of the above embodiment, but also diverges illumination light in the Y direction as diverging light.

[0039] (Variation 3) Next, a third modification will be described. Instead of the second lenticular lens 25 in the above embodiment, a concave mirror 29, which is an example of a first optical element, may be provided, as shown in Fig. 9. The concave mirror 29 reflects the illumination light toward the liquid crystal panel 27 so as to converge the illumination light as converging light in a direction corresponding to the X direction. This configuration can also achieve the same effects as the above embodiment. The configurations of the condenser lens 23, the first lenticular lens 24, and the second lenticular lens 25 are not limited to the above-described modifications 1 to 3, and further modifications are possible. For example, in the above embodiment, the cylindrical lens portions 24a and 24b of the first lenticular lens 24 are arranged so as to intersect with each other, but this is not limiting, and they may extend in the same direction. Also, for example, cylindrical lens portions extending in the Y direction and aligned in the X direction may be formed on both the entrance surface 24i and the exit surface 24o of the first lenticular lens 24 shown in Figure 7, and cylindrical lens portions extending in the X direction and aligned in the Y direction may be formed on the entrance surface 25i of the second lenticular lens 25 shown in Figure 8. Also, for example, two first lenticular lenses 24 may be arranged facing each other. The first lenticular lens may have cylindrical lens portions extending in the Y direction and aligned in the X direction on both its incident and exit surfaces, and the second lenticular lens may have cylindrical lens portions extending in the X direction and aligned in the Y direction on both its incident and exit surfaces.

[0040] In the above embodiment and the first modification, the second lenticular lens 25 may be provided upside down so that the entrance surface 25i and the exit surface 25o of the second lenticular lens 25 are opposite to each other. Furthermore, the diffuser 26 in the above embodiment can be omitted.

[0041] In the above embodiment, the second mirror 12 may be configured to be rotatable by a mirror driver around a rotation axis along the vehicle width direction. By rotating the second mirror 12 around the rotation axis, it becomes possible to adjust the irradiation position of the display light L on the viewer 1 in the height direction.

[0042] In the above embodiment, the head-up display device 100 is mounted on a vehicle, but the present invention is not limited to this and may be mounted on a vehicle such as an airplane, a ship, etc. Furthermore, the projection target member is not limited to the windshield 201 and may be a dedicated combiner. [Explanation of symbols]

[0043] 1. Viewer 11 1st mirror 11a,12a Reflective surface 12 Second mirror 20 Display Unit 21 Light source board 22 Light source 23 Condenser Lens 23a Convex lens part 24 First lenticular lens, second lens 24a, 24b Cylindrical lens part 24i,25i entrance plane 24o,25o injection surface 25 Second lenticular lens 26 Diffuser 27 LCD panel 28 Illumination optical system 29 Concave mirror 30 cases 31 Translucent window material 100 Head-up display device 200 vehicles 201 Windshield α Convergence angle β,θ divergence angle L display light V Virtual Image Cr Cross Point Lq ray path

Claims

1. a light source that emits light; a liquid crystal panel that receives light from the light source and emits display light; a first mirror that reflects the display light from the liquid crystal panel and crosses the reflected display light in a cross direction at a cross point; a second mirror that reflects the display light that has been reflected by the first mirror and passed through the cross point; a first optical element that converges light from the light source so that the display light reaches the first mirror in a converged state; a second optical element that substantially collimates the light emitted from the light source; a third optical element that diverges the light that has been substantially parallelized by the second optical element and then emits the diverged light to the first optical element, Head-up display device.

2. the incident surface and the exit surface of the third optical element are each formed in the shape of a cylindrical lens array extending in directions intersecting each other; The head-up display device according to claim 1 .

Images