Head-up display device

Abstract

To balance optimum light distribution characteristics of backlight for displaying a virtual image and a real image.SOLUTION: A head-up display device comprises: first light sources 11a for a virtual image VI; second light sources 11b for a real image RI; a display portion 12 that emits first display light L1 each including a first optical axis AX1 corresponding to light emitted from the first light source 11a and second display light L2 each including a second optical axis AX2 corresponding to light emitted from the second light source 11b; a reflection portion 13 that reflects the light emitted from the display portion 12 toward a windshield WS; a control portion 15 that performs control to turn on the first light sources 11a when the virtual image VI is visually recognized, and turn on the second light sources 11b when the real image RI is visually recognized; and a light distribution adjustment portion that sets the first optical axes AX1 to a first light distribution mode when the first light sources 11a are turned on, and sets the second optical axes AX2 to a second light distribution mode in which light distribution becomes narrower in a traveling direction than in the first light distribution mode when the second light sources 11b are turned on.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a head-up display device that allows a viewer to view a virtual image and a real image. [Background technology]

[0002] A display device described in Patent Document 1, for example, is known from the past. This display device displays an image to the viewer so that it appears as a virtual image located outside the vehicle. The image is displayed on a liquid crystal display panel, and the backlight is formed by light from a light source passing through a first lens to be collimated, then passing through a second lens and a third lens to spread vertically and horizontally, and then passing through a light diffusing member to be uniformized, illuminating the liquid crystal display panel from behind. In particular, each of the multiple light sources and the convex lens of the first lens (condenser lens) are arranged in a one-to-one relationship, and the optical axis of the most intense light ray from each light source is aligned with the central axis passing through the maximum point, which is the apex of the convex lens.

[0003] Furthermore, for example, the technology disclosed in Patent Document 2 is known as a technology for displaying a virtual image so as to be visually recognized at a position outside the vehicle, or a technology for displaying a real image so as to be visually recognized at a position inside the vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-218391 [Patent Document 2] Japanese Patent Publication No. 2022-129223 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in general, when a virtual image is displayed so that it can be seen, it is preferable that the optimal light distribution of the backlight be a wide light distribution, while when a real image is displayed so that it can be seen, it is preferable that the optimal light distribution of the backlight be a narrow light distribution. Therefore, the optimal light distributions for each are different, and there is a problem that if one of the light distribution characteristics is used, the efficiency of the other will be reduced.

[0006] Therefore, the present invention has been made in consideration of the above problems, and aims to provide a head-up display device that achieves optimal backlight light distribution characteristics for displaying both virtual images and real images. [Means for solving the problem]

[0007] The present invention provides a head-up display device 1 having an outlet 17, and emitting display light L from the outlet 17 toward a light-transmitting member WS, thereby allowing a virtual image VI and a real image RI of a display image represented by the display light L to be visually recognized. The head-up display device 1 includes a display unit 12 including a plurality of first light sources 11a for the virtual images VI, a plurality of second light sources 11b for the real images RI, and a display element 123, and emitting first display light L1 having a plurality of first optical axes AX1 corresponding to the light emitted from the plurality of first light sources 11a and second display light L2 having a plurality of second optical axes AX2 corresponding to the light emitted from the plurality of second light sources 11b; The optical system is characterized by comprising a reflecting unit 13 that reflects light toward a light-transmitting member WS, a control unit 15 that controls the plurality of first light sources 11a to be turned on when the virtual image VI is to be viewed, and controls the plurality of second light sources 11b to be turned on when the real image RI is to be viewed, and light distribution adjustment units 121a, 121b, 125a, and 128 that, when the control unit 15 turns on the plurality of first light sources 11a, set the entire plurality of first optical axes AX1 to a first light distribution pattern, and, when the control unit 15 turns on the plurality of second light sources 11b, set the entire plurality of second optical axes AX2 to a second light distribution pattern that is narrower in the light traveling direction than the first light distribution pattern. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a head-up display device that achieves both a first light distribution pattern when a virtual image is viewed and a second light distribution pattern when a real image is viewed, as optimal light distributions. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a configuration for generating a virtual image in a head-up display device according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing a configuration for generating a real image in a head-up display device according to a first embodiment of the present invention. [Figure 3] 1 is a schematic diagram showing the structure of a PGU (Picture Generation Unit) in a head-up display device according to a first embodiment of the present invention. [Figure 4] 3A and 3B are schematic diagrams showing the effect of light of a PGU in the head-up display device according to the first embodiment of the present invention. [Figure 5] FIG. 10 is a diagram showing a configuration for generating a virtual image in a head-up display device according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing a configuration for generating a real image in a head-up display device according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a schematic diagram showing the structure of a PGU when a first light source is arranged on one side and a second light source is arranged on the other side in a head-up display device according to a second embodiment of the present invention. [Figure 8] FIG. 10 is a schematic diagram showing the structure of a PGU when a first light source is arranged on the other side and a second light source is arranged on one side in a head-up display device according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a schematic diagram showing the structure of a PGU in a head-up display device according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a schematic diagram showing the structure of a PGU in a head-up display device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment of the present invention) A head-up display device (hereinafter referred to as HUD device) according to this embodiment will be described with reference to Fig. 1 to Fig. 4. Fig. 1 is a diagram showing the configuration when a virtual image is generated in the HUD device according to this embodiment, and Fig. 2 is a diagram showing the configuration when a real image is generated in the HUD device according to this embodiment.

[0011] 1 and 2, the HUD device 1 includes a PGU 10 having at least a plurality of light sources 11 emitting white light, each composed of light-emitting diodes emitting light in the visible wavelength range mounted on a wiring board, a display unit 12 that generates an image using the light incident from the light sources 11 and displays the image by switching the polarization of the emitted light between a first polarization and a second polarization, a reflector 13 that reflects display light L representing the display image displayed on the display unit 12 (first display light L1 representing a virtual image VI in the case of FIG. 1, and second display light L2 representing a real image RI in the case of FIG. 2) toward a windshield WS (a light-transmitting member), and a control unit 15 that controls the lighting state of the light sources 11, the display content on the display unit 12, and the switching between the first polarization and the second polarization, and all of these are housed in a housing 16. The housing 16 is provided with an opening 17 (exit) through which the display light L is emitted, and a cover glass 18 is disposed in the opening 17 to protect the interior. The windshield WS is an example of a light-projecting member, and the opening 17 is an example of an emission port.

[0012] The HUD device 1 is disposed below the windshield WS of the vehicle Ca (for example, inside the instrument panel), and emits display light L (first display light L1, second display light L2) and projects it onto the windshield WS. The display light L is generated by a light source 11 and a display unit 12 inside the HUD device 1. The display light L emitted from the display unit 12 travels along a reflector 13 and is emitted from an opening 17 in a housing 16 through a cover glass 18. By viewing the first display light L1 reflected by the windshield WS, the driver DR of the vehicle Ca can view a virtual image VI as shown in FIG. 1 on the far side of the windshield WS, and by viewing the second display light L2 reflected by the windshield WS, the driver DR can view a real image RI as shown in FIG. 2 on the near side of the windshield WS.

[0013] The virtual image VI shown in FIG. 1 displays information that is highly necessary to draw the driver DR's attention, such as vehicle information such as the vehicle speed and engine RPM, route guidance displays such as turn-by-turn directions and maps, blind spot indicators, and warning displays such as speed limit exceeding warnings, on the other side of the windshield WS as viewed from the driver DR. The real image RI shown in FIG. 2 displays, for example, entertainment content, assistants and agents supporting the driver DR, and characters representing them, on the front side of the windshield WS as viewed from the driver DR. These displays provide a driving environment that reduces the need to move the driver's viewpoint and adjust the focal length of the eyes. The virtual image VI and real image RI include background portions as well as characters and icons indicating this information, and in a planar view from the driver DR, they have, for example, a substantially rectangular shape.

[0014] In addition, the switching between displaying the virtual image VI and the real image RI is synchronized with, for example, the driving mode, and is controlled so that the virtual image VI is displayed in the manual driving mode, and so that the real image RI is displayed in the automatic driving mode.

[0015] Here, the configuration of the PGU 10 will be described. Fig. 3 is a schematic diagram showing the structure of the PGU 10 in the HUD device 1 according to this embodiment. The PGU 10 includes a plurality of first light sources 11a for virtual images and a plurality of second light sources 11b for real images, which are arranged on a PCB (printed circuit board) 111, a first condenser lens (light distribution adjustment unit) 121a arranged downstream of the first light sources 11a and the second light sources 11b (on the side in the direction in which light travels), a diffuser 122 arranged downstream of the first condenser lens 121a, a TFT (Thin Film Transistor) 123 (display element) arranged downstream of the diffuser 122, and a polarization switching element 124 arranged downstream of the TFT 123, which switches the polarization of the emitted light between first and second polarized lights that are different from each other.

[0016] The first light source 11a and the second light source 11b have a first optical axis AX1 and a second optical axis AX2, respectively, which are normal to the PCB 111 (the direction in which the most intense light from each light source 11 travels). The first condenser lens 121a has a light-receiving surface that is a flat surface parallel to the PCB 111, and has multiple convex lenses on its exit surface. At least one first light source 11a and one second light source 11b are arranged to correspond to one convex lens in the first condenser lens 121a. The first light source 11a and the second light source 11b are arranged so that, for each convex lens in the first condenser lens 121a, the first optical axis AX1 of the corresponding first light source 11a substantially coincides with a central axis C that passes through the apex (maximum point) of the convex lens, and the second optical axis AX2 of the corresponding second light source 11b is positioned offset from the central axis C.

[0017] Specifically, the second optical axis AX2 of the second light source 11b is arranged such that it is displaced in the outer direction of the PGU10 with respect to the central axis C (or in the outer direction of the central axis X of the first condenser lens 121a). That is, as shown in FIG. 3, the second light sources 11b (one-sided second light sources) arranged in the left half of the PCB111 among the plurality of second light sources 11b (the left (L in the figure) half of the boundary of the central axis X of the first condenser lens 121a in the paper surface direction of FIG. 3) are all located on the left side (one side) of the central axis C of the corresponding convex lens, that is, on the left side of the corresponding first light source 11a. The second light sources 11b (the other-sided second light sources) arranged in the right half of the PCB111 among the plurality of second light sources 11b (the right (R in the figure) half of the boundary of the central axis X of the first condenser lens 121a in the paper surface direction of FIG. 3) are all located on the right side (the other side) of the central axis C of the corresponding convex lens, that is, on the right side of the corresponding first light source 11a.

[0018] In addition, when one set consists of one first light source 11a and one second light source 11b corresponding to one convex lens among the plurality of first light sources 11a and the plurality of second light sources 11b, it is desirable to arrange them such that the distance W2 between one set of the first light source 11a and the second light source 11b that is far from the central axis X of the first condenser lens 121a is larger than the distance W1 between one set of the first light source 11a and the second light source 11b that is close to the central axis X, that is, W1 < W2.

[0019] The diffusion plate 122 and the TFT 123 are arranged in parallel, and their respective normal directions and the normal direction of the PCB111 are arranged in a state inclined at a predetermined angle θ. This is a measure to exclude stray light (light leaking from the first light source 11a or the second light source 11b) and external light (light entering from the outside) from the optical paths of the first display light L1 and the second display light L2. The polarization switching element 124 arranged on the subsequent stage side of the TFT 123 is arranged to be parallel to the PCB111 and converts the polarization of the transmitted light. For example, by applying or not applying a voltage, or physically rotating a polarizing plate or a wavelength plate at a predetermined angle with the optical axis direction as the central axis direction, it is possible to switch between the first polarization and the second polarization.

[0020] Next, the function of light in the PGU 10 shown in Fig. 3 will be described. Fig. 4 is a schematic diagram showing the function of light in the PGU 10 in the HUD device 1 according to this embodiment. For example, when the driving mode is the manual driving mode, the control unit 15 controls the lighting of only the first light source 11a for displaying the virtual image VI. The light emitted from the first light source 11a passes through the first condenser lens 121a and is incident on the diffuser plate 122 in a state where it is collimated along the central axis C (first light distribution pattern). The light is then homogenized by passing through the diffuser plate 122. The homogenized light is used by the TFT 123 to generate image light to be displayed as the virtual image VI. The homogenized light then passes through the polarization switching element 124, which has been switched by the control unit 15 to an S-polarized light conversion element, and is then emitted from the PGU 10 as the S-polarized first display light L1.

[0021] Furthermore, for example, when the driving mode is the automatic driving mode, the control unit 15 controls so that only the second light source 11b for displaying a real image RI is turned on. The light emitted from the second light source 11b passes through the first condenser lens 121a, and is incident on the diffuser plate 122 in a state where it is refracted in the direction of the central axis X when it is emitted from the first condenser lens 121a (second light distribution pattern), and is homogenized by passing through the diffuser plate 122. From the homogenized light, image light to be displayed as a real image RI is generated by the TFT 123, and the homogenized light passes through the polarization switching element 124, which has been switched by the control unit 15 to a conversion element to P-polarized light, and is then emitted from the PGU 10 as P-polarized second display light L2.

[0022] That is, as shown in FIG. 4, compared to the light distribution characteristic of the first display light L1 representing the display image of the virtual image VI, the light distribution characteristic of the second display light L2 representing the display image of the real image RI becomes a light distribution characteristic that gradually narrows in the direction in which the light travels.

[0023] In this description, the first polarized light is S-polarized light and the second polarized light is P-polarized light, but the P and S polarized light may be reversed. Furthermore, the first polarized light and the second polarized light are not limited to P and S polarized light, as long as the polarization angles of the first and second polarized light are different, and it is desirable that the polarization angles differ by at least 22.5 degrees, for example.

[0024] The first display light L1 and the second display light L2 emitted from the PGU 10 travel through the reflecting unit 13 and are reflected by the windshield WS. In FIGS. 1 and 2, the reflecting unit 13 includes a first mirror 131, a second mirror 132, and a third mirror 133, each of which is a concave mirror. The first mirror 131 reflects the first display light L1, which is S-polarized light, as a first polarization, and transmits the second display light L2, which is P-polarized light, as a second polarization. The second mirror 132 reflects the second display light L2 that transmits through the first mirror 131. The first display light L1 and the second display light L2 reflected by the first mirror 131 and the second mirror 132 are guided to the third mirror 133, reflected by the third mirror 133, and emitted to the windshield WS, allowing the driver DR to view the display images, i.e., the virtual image VI and the real image RI.

[0025] Although countless rays of light are actually emitted from the PGU 10, for ease of explanation, the light emitted from the center of the display unit 12 and passing through the center of the eyebox is referred to as a representative ray and is indicated by the symbol L. In addition, in Figures 1 and 2, and Figures 5 and 6 described below, only the representative ray emitted from the center of the display unit 12 is shown by a solid line.

[0026] 2, the first mirror 131 is a mirror that transmits the second display light L2, and therefore the second display light L2 reflected by the second mirror 132 can also be transmitted from the rear side where the second mirror 132 is located to the front side. That is, as shown in FIG. 2, the second display light L2 that has transmitted through the first mirror 131 is reflected by the second mirror 132, transmitted through the first mirror 131 again, and guided to the third mirror 133. This makes it possible to arrange the second mirror 132 close to the rear side of the first mirror 131, and prevents the housing 16 from becoming large.

[0027] 1, a composite focal point F of the optical system consisting of the first mirror 131, the third mirror 133, and the windshield WS is disposed in front of the PGU 10. As a result, the first display light L1 is formed into an image on the far side of the windshield WS (on the vehicle exterior side), and the driver DR views the first display light L1 as a virtual image VI. Also, in FIG. 2, a composite focal point F of the optical system consisting of the second mirror 132, the third mirror 133, and the windshield WS is disposed in back of the PGU 10. As a result, the second display light L2 is formed into an image on the near side of the windshield WS (on the vehicle interior side), and the driver DR views the second display light L2 as a real image RI.

[0028] As described above, the HUD device 1 according to this embodiment includes a plurality of first light sources 11a for a virtual image VI, a plurality of second light sources 11b for a real image RI, a display unit 12 that includes a TFT 123 and emits first display light L1 having a plurality of first optical axes AX1 corresponding to the light emitted from the plurality of first light sources 11a and second display light L2 having a plurality of second optical axes AX2 corresponding to the light emitted from the plurality of second light sources 11b, a reflecting unit 13 that reflects the first display light L1 and the second display light L2 emitted from the display unit 12 toward the windshield WS, a control unit 15 that controls the plurality of first light sources 11a to be turned on when the virtual image VI is to be viewed and controls the plurality of second light sources 11b to be turned on when the real image RI is to be viewed, and a control unit 15 that controls the plurality of first light sources 11a to be turned on when the real image RI is to be viewed. The light distribution adjustment unit is configured to set the entire plurality of first optical axes AX1 to a first light distribution pattern when the light source 11a is turned on, and to set the entire plurality of second optical axes AX2 to a second light distribution pattern that is narrower in the light traveling direction than the first light distribution pattern when the control unit 15 turns on the plurality of second light sources 11b.Therefore, the second light distribution pattern of the second optical axis AX2 when the second light source 11b is turned on and the second display light L2 is emitted to make the real image RI visible is narrower than the first light distribution pattern of the first optical axis AX1 when the first light source 11a is turned on and the first display light L1 is emitted to make the virtual image VI visible, thereby achieving both an optimal wide light distribution when displaying the virtual image VI and an optimal narrow light distribution when displaying the real image RI.

[0029] In addition, the light distribution adjustment unit has a first condenser lens 121a equipped with multiple convex lenses on the output side, and the first condenser lens 121a is arranged so that, for each convex lens, the corresponding first optical axis AX1 approximately coincides with the central axis C passing through the vertex of the convex lens, and the corresponding second optical axis AX2 is positioned offset from the central axis C.This makes it possible to achieve optimal light distribution characteristics in which the first optical axis AX1 is a parallel light when viewing a virtual image VI, and the second optical axis AX2 is a light distribution pattern that is narrower than that of parallel light when viewing a real image RI.

[0030] Furthermore, since the multiple second light sources 11b include multiple one-side second light sources 11b located on one side of the central axis C of the corresponding convex lens, and multiple other-side second light sources 11b located on the other side of the central axis C of the corresponding convex lens, the second optical axis AX2 when viewing the real image RI can have a light distribution characteristic that gradually narrows symmetrically toward the central axis X of the entire first condenser lens 121a.

[0031] Furthermore, the multiple first light sources 11a and the multiple second light sources 11b are arranged such that, when one corresponding first light source 11a and one corresponding second light source 11b are considered as one set, the distance W2 between the set of first light source 11a and second light source 11b that is farther away from the central axis X of the first condenser lens 121a is greater than the distance W1 between the set of first light source 11a and second light source 11b that is closer to the central axis X. Therefore, a specific configuration can reliably achieve a narrower light distribution characteristic due to refraction in the direction of the central axis X when viewing a real image RI, compared to parallel light along the central axis C when viewing a virtual image VI.

[0032] (Second embodiment of the present invention) The HUD device 1 according to this embodiment will be described with reference to Fig. 5 to Fig. 8. Fig. 5 is a diagram showing a configuration in which a virtual image VI is generated in the HUD device 1 according to this embodiment, and Fig. 6 is a diagram showing a configuration in which a real image RI is generated in the HUD device 1 according to this embodiment. Note that descriptions in this embodiment that overlap with those in the first embodiment will be omitted.

[0033] 5 and 6, the HUD device 1 includes a PGU 10 having at least a light source 11 and a display unit 12 that generates an image using light incident from the light source 11 and switches the polarization of the emitted light between different first and second polarizations for display; a reflecting unit 13 that reflects display light L representing the display image displayed on the display unit 12 (first display light L1 representing the display image of a virtual image VI in the case of FIG. 5, and second display light L2 representing the display image of a real image RI in the case of FIG. 6) toward the windshield WS; and a control unit 15 that controls the lighting state of the light source 11, controls the display content on the display unit 12, and controls switching between the first polarization and the second polarization, and these are housed in a housing 16.

[0034] The HUD device 1 is disposed below the windshield WS of a vehicle Ca (for example, inside the instrument panel), and emits first display light L1 and second display light L2, which are projected onto the windshield WS. The first display light L1 and second display light L2 are generated by a light source 11 and a display unit 12 inside the HUD device 1. The first display light L1 and second display light L2 emitted from the display unit 12 travel along a reflecting unit 13 and are emitted from an opening 17 in a housing 16 through a cover glass 18. By viewing the first display light L1 reflected by the windshield WS, the driver DR can view a virtual image VI on the far side of the windshield WS as shown in FIG. 5 and a virtual image VI on the near side of the windshield WS as shown in FIG. 6.

[0035] Here, the configuration of the PGU 10 will be described. Figures 7 and 8 are schematic diagrams showing the structure of the PGU 10 in the HUD device 1 according to this embodiment. Figure 7 shows a structure in which all of the first light sources 11a are arranged on one side of the central axis C and all of the second light sources 11b are arranged on the other side, while Figure 8 shows a structure in which all of the first light sources 11a are arranged on the other side of the central axis C and all of the second light sources 11b are arranged on one side. As shown in Figures 7 and 8, the PGU10 includes a plurality of first light sources 11a for virtual images and a plurality of second light sources 11b for real images arranged on the PCB 111, a second condenser lens 121b (light distribution adjustment unit) arranged downstream of the first light sources 11a and the second light sources 11b, a diffuser 122 arranged downstream of the second condenser lens 121b, a TFT (Thin Film Transistor) 123 (display element) arranged downstream of the diffuser 122, and a polarization switching element 124 arranged downstream of the TFT 123 for switching the polarization of the emitted light between different first and second polarizations.

[0036] The first light source 11a and the second light source 11b have a first optical axis AX1 and a second optical axis AX2, respectively, which are normal to the PCB 111. The second condenser lens 121b has a light-receiving surface that is a plane parallel to the PCB 111, and has a plurality of convex lenses on its exit surface. At least one of the first light source 11a and one of the second light source 11b are arranged to correspond to one convex lens in the second condenser lens 121b. The first light source 11a and the second light source 11b are arranged such that, for each convex lens in the second condenser lens 121b, the first optical axis AX1 of the corresponding first light source 11a and the second optical axis AX2 of the corresponding second light source 11b are positioned opposite each other across the central axis C that passes through the vertex (maximum point) of the convex lens.

[0037] 7, for example, the first optical axes AX1 of the first light sources 11a are all disposed to be located on the right side (the right side (R in the drawing) when facing the paper surface of FIG. 7) (the other side) of the central axis C, and the second optical axes AX2 of the second light sources 11b are all disposed to be located on the left side (the left side (L in the drawing) when facing the paper surface of FIG. 7) (one side) of the central axis C. In this case, the first light sources 11a and the second light sources 11b are disposed such that the distance from the central axis C of at least one of the plurality of first light sources 11a and the plurality of second light sources 11b decreases stepwise from the light source on one end side to the light source on the other end side.

[0038] 7, for example, the distance W3 between the first light source 11a and the central axis C is greater for the first light source 11a located closer to the left end (one end) and decreases stepwise toward the first light source 11a located closer to the right end (the other end).Furthermore, the distance W4 between the second light source 11b and the central axis C is greater for the second light source 11b located closer to the left end and decreases stepwise toward the second light source 11b located closer to the right end.

[0039] The light for the virtual image VI emitted from the first light source 11a is refracted in the direction of the central axis C when passing through the second condenser lens 121b, and is emitted to the opposite side after passing through the central axis C. Similarly, the light for the real image RI emitted from the second light source 11b is refracted in the direction of the central axis C when passing through the second condenser lens 121b, and is emitted to the opposite side after passing through the central axis C.

[0040] In other words, in the case of the arrangement configuration shown in Figure 7, the light emitted from the first light source 11a for the virtual image VI has a light distribution characteristic that is wider in the direction in which the light travels, and the light emitted from the second light source 11b for the real image RI has a light distribution characteristic that is narrower in the direction in which the light travels.

[0041] In addition, in Figure 7, both the distance W3 and the distance W4 are shown to decrease stepwise from the left end side to the right end side, but as described above, the first light source 11a and the second light source 11b may be arranged so that only one of the light sources has a variable distance between the light source and the central axis C.

[0042] In the case of Fig. 8, the first optical axis AX1 of the first light source 11a is arranged to be located on the left side (the left side (L in Fig. 8) when facing the paper surface) (the other side) of the central axis C, and the second optical axis AX2 of the second light source 11b is arranged to be located on the right side (the right side (R in Fig. 8) when facing the paper surface) (one side) of the central axis C. In this case, the first light source 11a and the second light source 11b are arranged such that the distance from the central axis C of at least one of the plurality of first light sources 11a and the plurality of second light sources 11b increases stepwise from the light source on one end side to the light source on the other end side.

[0043] 8, the distance W3 between the first light source 11a and the central axis C is smaller for the first light source 11a arranged closer to the left end (one end) and gradually increases toward the first light source 11a arranged closer to the right end (the other end). Also, the distance W4 between the second light source 11b and the central axis C is smaller for the second light source 11b arranged closer to the left end and gradually increases toward the second light source 11b arranged closer to the right end.

[0044] The light for the virtual image VI emitted from the first light source 11a is refracted in the direction of the central axis C when passing through the second condenser lens 121b, and is emitted to the opposite side after passing through the central axis C. Similarly, the light for the real image RI emitted from the second light source 11b is refracted in the direction of the central axis C when passing through the second condenser lens 121b, and is emitted to the opposite side after passing through the central axis C.

[0045] In other words, in the case of the arrangement configuration shown in Figure 8, the light emitted from the first light source 11a for the virtual image VI has a broad light distribution characteristic, and the light emitted from the second light source 11b for the real image RI has a narrow light distribution characteristic.

[0046] In addition, in Figure 8, both the distance W3 and the distance W4 are shown to increase stepwise from the left end side to the right end side, but as described above, the first light source 11a and the second light source 11b may be arranged so that only one of the light sources has a variable distance between the light source and the central axis C.

[0047] 7 and 8, when both the distance W3 and the distance W4 are variable in stages from the left end side to the right end side, the first light source 11a and the second light source 11b may be arranged symmetrically with respect to the central axis C.

[0048] The light from the first light source 11a that has passed through the second condenser lens 121b is incident on the diffuser plate 122 and is uniformized by passing through the diffuser plate 122. From the uniformized light, image light that is displayed as a virtual image VI is generated by the TFT 123, and the uniformed light passes through the polarization switching element 124, which has been switched by the control unit 15 to an element for converting to S-polarized light, and is then emitted from the PGU 10 as S-polarized first display light L1.

[0049] The light from the second light source 11b that has passed through the second condenser lens 121b is incident on the diffuser plate 122 and is uniformized by passing through the diffuser plate 122. From the uniformized light, image light that is displayed as a real image RI is generated by the TFT 123, and the uniformed light passes through the polarization switching element 124, which has been switched by the control unit 15 to a conversion element for converting to P-polarized light, and is then emitted from the PGU 10 as P-polarized second display light L2.

[0050] That is, as shown in Figures 7 and 8, compared to the light distribution characteristics of the first display light L1 representing the display image of the virtual image VI, the light distribution characteristics of the second display light L2 representing the display image of the real image RI become narrower in the direction in which the light travels.

[0051] In this description, the first polarized light is S-polarized light and the second polarized light is P-polarized light, but the P and S polarized light may be reversed. Furthermore, the first polarized light and the second polarized light are not limited to P and S polarized light, as long as the polarization angles of the first and second polarized light are different, and it is desirable that the polarization angles differ by at least 22.5 degrees, for example.

[0052] The first display light L1 and the second display light L2 emitted from the PGU 10 are reflected by the windshield WS through the reflector 13. The reflector 13 shown in FIGS. 5 and 6 includes a fourth mirror 1311, a fifth mirror 1321, and a sixth mirror 1331, each of which has a flat surface or a curved surface. The display light L emitted from the PGU 10 is reflected by the fourth mirror 1311 and the sixth mirror 1331, or by the fifth mirror 1321 and the sixth mirror 1331 and is guided to the windshield WS, allowing the driver DR to view the display images, the virtual image VI and the real image RI.

[0053] Fourth mirror 1311 and fifth mirror 1321 each have the property of reflecting or transmitting light rays with specific polarizations, and here, for example, fourth mirror 1311 reflects light rays with P polarization as the first polarization and transmits light rays with S polarization as the second polarization, while fifth mirror 1321 transmits light rays with P polarization and reflects light rays with S polarization.

[0054] 7 and 8, the first display light L1 and the second display light L2 are refracted when passing through the second condenser lens 121b, causing their emission directions to differ from each other. That is, in the configuration shown in FIG. 5, the first display light L1 is switched to P-polarized light by the polarization switching element 124, and the P-polarized first display light L1 is emitted in the direction of the fourth mirror 1311. In the configuration shown in FIG. 6, the PGU 10 is configured to switch the second display light L2 to S-polarized light by the polarization switching element 124, and the S-polarized second display light L2 is emitted in the direction of the fifth mirror 1321. The first display light L1 reflected by the fourth mirror 1311 and the second display light L2 reflected by the fifth mirror 1321 are then guided to the sixth mirror 1331.

[0055] 5, when the fourth mirror 1311, the sixth mirror 1331, and the windshield WS are regarded as a single optical system, the fourth mirror 1311 is disposed with the display unit 12 located closer to the composite focal point F of the optical system. Also, when the fifth mirror 1321, the sixth mirror 1331, and the windshield WS are regarded as a single optical system in FIG. 6, when the fifth mirror 1321, the sixth mirror 1331, and the windshield WS are regarded as a single optical system, the fifth mirror 1321 is disposed with the display unit 12 located farther from the composite focal point F of the optical system. By disposing the fourth mirror 1311 and the fifth mirror 1321 in this manner, the display image displayed by the first display light L1 is perceived as a virtual image VI located far from the driver DR, and the display image displayed by the second display light L2 is perceived as a real image RI located close to the driver DR.

[0056] As in the first embodiment, the control unit 15 shown in FIGS. 5 and 6 switches the illumination of the first light source 11a and the second light source 11b, controls the display content on the display unit 12, and controls the switching of polarization of the polarization switching element 124, depending on whether the driving mode is an automatic driving mode or a manual driving mode, for example.

[0057] 5 to 8, the emission direction of the first display light L1 and the second display light L2 can be arbitrarily adjusted depending on the arrangement of the second condenser lens 121b and the first light source 11a and the second light source 11b, and the arrangement of the fourth mirror 1311, the fifth mirror 1321, and the sixth mirror 1331, which are the reflecting unit 13, can be arbitrarily adjusted depending on the emission direction of the first display light L1 and the second display light L2.

[0058] As described above, in the HUD device 1 according to this embodiment, the light distribution adjustment unit has a second condenser lens 121b equipped with a plurality of convex lenses on the output side, and the plurality of second light sources 11b are located on one side of the central axis C passing through the vertices of the corresponding convex lenses, and the plurality of first light sources 11a are located on the other side of the central axis C passing through the vertices of the corresponding convex lenses. Therefore, the position of incidence of light relative to each convex lens can be adjusted from the arrangement of the first light source 11a on one side and the second light source 11b on the other side, and the output angles of the first display light L1 and the second display light L2 can be made different, thereby switching between displaying a virtual image VI and a real image RI.

[0059] Furthermore, at least one of the plurality of first light sources 11a and the plurality of second light sources 11b is arranged so that the distance between each light source and the corresponding central axis C increases or decreases in stages. Therefore, by narrowing the light distribution of the second display light L2 when a real image is viewed relative to the first display light L1 when a virtual image is viewed, appropriate light distribution characteristics can be achieved.

[0060] (Third embodiment of the present invention) The HUD device 1 according to this embodiment will be described with reference to Fig. 9. The HUD device 1 according to this embodiment differs from the configuration of the PGU 10 in the configurations of Figs. 1 and 2 described in the first embodiment. Note that descriptions of this embodiment that overlap with those of the first and second embodiments will be omitted.

[0061] 9 is a schematic diagram showing the structure of PGU 10 in HUD device 1 according to this embodiment. As shown in Fig. 9, PGU 10 includes a plurality of first light sources 11a for virtual images and a plurality of second light sources 11b for real images, which are arranged on PCB 111, a third condenser lens 121c arranged downstream of first light sources 11a and second light sources 11b, a first field lens 125a (light distribution adjustment unit) arranged downstream of third condenser lens 121c, a diffuser plate 122 arranged downstream of first field lens 125a, a TFT (Thin Film Transistor) 123 (display element) arranged downstream of diffuser plate 122, and a polarization switching element 124 arranged downstream of TFT 123, which switches the polarization of emitted light between first and second polarized light that are different from each other.

[0062] The first light source 11a and the second light source 11b have a first optical axis AX1 and a second optical axis AX2, respectively, which are normal to the PCB 111. The third condenser lens 121c has a light-receiving surface that is a plane parallel to the PCB 111, and has multiple convex lenses on its exit surface. One first light source 11a or one second light source 11b is disposed corresponding to each convex lens in the third condenser lens 121c. The first field lens 125a has, on its exit side, a first convex lens 125aL on one side of the central axis Y of the first field lens 125a (the left side in FIG. 9, or L side in FIG. 9) and a second convex lens 125aR on the other side of the central axis Y (the right side in FIG. 9, or R side in FIG. 9).

[0063] In the first convex lens 125aL, two third convex lenses 121dL (third convex lenses) on one side of the third condenser lens 121c (in Figure 9, the left side (L side) facing the paper surface) are arranged corresponding to the incident side, and in the second convex lens 125aR, two third convex lenses 121dR (third convex lenses) on the other side of the third condenser lens 121c (in Figure 9, the right side (R side) facing the paper surface) are arranged corresponding to the incident side.

[0064] 9, the second optical axis AX2 of the second light source 11b is associated with the central axis C passing through the apex of the convex lens on one side of the third convex lens 121dL (the left side (L side in FIG. 9) as viewed in the plane of the paper), and the first optical axis AX1 of the first light source 11a is associated with the central axis C passing through the apex of the convex lens on the other side of the third convex lens 121dL (the right side (R side in FIG. 9) as viewed in the plane of the paper). Also, the first optical axis AX1 of the first light source 11a is associated with the central axis C passing through the apex of the convex lens on one side of the third convex lens 121dR (the left side (L side in FIG. 9) as viewed in the plane of the paper), and the second optical axis AX2 of the second light source 11b is associated with the central axis C passing through the apex of the convex lens on the other side of the third convex lens 121dR (the right side (R side in FIG. 9) as viewed in the plane of the paper).

[0065] That is, for example, as shown in FIG. 9, the first light source 11a and the second light source 11b corresponding to the first convex lens 125aL are arranged so that the second optical axis AX2 of the second light source 11b is positioned on the left side (the left side (L in the drawing) as viewed in FIG. 9) (one side) of the central axis CL of the first convex lens 125aL, and the first optical axis AX1 of the first light source 11a is positioned on the right side (the right side (R in the drawing) as viewed in FIG. 9) (the other side) of the central axis CL. Furthermore, the first light source 11a and the second light source 11b corresponding to the second convex lens 125aR are arranged so that the second optical axis AX2 of the second light source 11b is positioned on the right side (the right side (R in the drawing) as viewed in the plane of Figure 9) (the other side) of the central axis CR of the second convex lens 125aR, and the first optical axis AX1 of the first light source 11a is positioned on the left side (the left side (L in the drawing) as viewed in the plane of Figure 9) (one side) of the central axis CR.

[0066] In FIG. 9, the first field lens 125a has two convex lenses, a first convex lens 125aL and a second convex lens 125aR, and the third condenser lens 121c has two third convex lenses 121dL and two third convex lenses 121dR corresponding to the respective convex lenses, and one first light source 11a or one second light source 11b is arranged corresponding to each of the third convex lenses 121dL, 121dR. However, the number of convex lenses that the first field lens 125a has may be three or more, and even in that case, the third condenser lens 121c may have two third convex lenses 121dL, 121dR corresponding to the respective convex lenses, and one first light source 11a or one second light source 11b may be arranged corresponding to each of the third convex lenses 121dL, 121dR.

[0067] 9, the first light source 11a and the second light source 11b corresponding to the first convex lens 125aL may be arranged symmetrically with respect to the central axis CL. Furthermore, the first light source 11a and the second light source 11b corresponding to the second convex lens 125aR may also be arranged symmetrically with respect to the central axis CR.

[0068] As described in the second embodiment, the first display light L1 and the second display light L2 emitted from the PGU 10 shown in FIG. 9 travel along the reflecting portion 13 and are reflected by the windshield WS, causing the driver DR to view the virtual image VI or the real image RI.

[0069] In this way, the light distribution adjustment unit has a first field lens 125a equipped with a first convex lens 125aL and a second convex lens 125aR on the output side, and in the first convex lens 125aL, the corresponding second optical axis AX2 is located on one side of the central axis CL passing through the apex of the first convex lens 125aL, and the corresponding first optical axis AX is located on the other side of the central axis CL passing through the apex of the first convex lens 125aL. The second optical axis AX2 is located on the other side of the central axis CR passing through the apex of the second convex lens 125aR, and the corresponding first optical axis AX1 is located on one side of the central axis CR passing through the apex of the second convex lens 125aR. Therefore, by arranging the first optical axis AX1 on the inner side of the first field lens 125a and the second optical axis AX2 on the outer side, it is possible to make the first optical axis AX1 have a wide light distribution when a virtual image is viewed, and the second optical axis AX2 have a narrow light distribution when a real image is viewed.

[0070] Furthermore, in the first convex lens 125aL, the corresponding first optical axis AX1 and second optical axis AX2 are arranged at positions that are linearly symmetrical to each other with respect to the central axis CL that passes through the vertex of the first convex lens 125aL, and in the second convex lens 125aR, the corresponding first optical axis AX1 and second optical axis AX2 are arranged at positions that are linearly symmetrical to each other with respect to the central axis CR that passes through the vertex of the second convex lens 125aR, so that it is possible to realize a light distribution characteristic that gradually widens symmetrically with respect to the first optical axis AX1 when viewing a virtual image VI, and a light distribution characteristic that gradually narrows symmetrically with respect to the second optical axis AX2 when viewing a real image RI.

[0071] Furthermore, the optical system further includes a third condenser lens 121c that is arranged closer to the first light source 11a and the second light source 11b than the first field lens 125a and has a plurality of third convex lenses 121dL, 121dR on the output side. In the third condenser lens 121c, two third convex lenses 121dL are arranged on the incident side of the first convex lens 125aL of the first field lens 125a, and two third convex lenses 121dR are arranged on the incident side of the second convex lens 125aR of the first field lens 125a. Therefore, the specific configuration can reliably realize a light distribution characteristic that gradually widens symmetrically about the first optical axis AX1 when a virtual image VI is viewed, and a light distribution characteristic that gradually narrows symmetrically about the second optical axis AX2 when a real image RI is viewed.

[0072] (Fourth embodiment of the present invention) The HUD device 1 according to this embodiment will be described with reference to Fig. 10. The HUD device 1 according to this embodiment differs from the configuration of the PGU 10 in the configurations of Figs. 5 and 6 described in the second embodiment. Note that descriptions of this embodiment that overlap with those of the first to third embodiments will be omitted.

[0073] Fig. 10 is a schematic diagram showing the structure of PGU 10 in HUD device 1 according to this embodiment. In PGU 10 shown in Fig. 10, the arrangement of first light source 11a, second light source 11b, and second condenser lens 121b is the same as in Fig. 7, but distances W3 and W4 are set to the same distances. Furthermore, in the configuration of PGU 10 shown in Fig. 7, first lenticular lens 126 and second lenticular lens 127 are provided between second condenser lens 121b and diffuser plate 122 to condense light emitted from second condenser lens 121b in the horizontal and vertical directions, respectively, and a single second field lens 128 (light distribution adjustment unit) including an incident-side convex lens 128a and an exit-side convex lens 128b is provided downstream of the first lenticular lens 126 and second lenticular lens 127.

[0074] As shown in FIG. 10, the second field lens 128 emits a plurality of first optical axes AX1 as parallel light (first light distribution pattern) from the output-side convex lens 128b in response to the light emitted from a plurality of first light sources 11a that has entered through the input-side convex lens 128a, and emits a plurality of second optical axes AX2 from the output-side convex lens 128b in response to the light emitted from a plurality of second light sources 11b that has entered through the input-side convex lens 128a, with a light distribution (second light distribution pattern) that narrows in the direction in which the light travels compared to the parallel light.

[0075] As in the second embodiment, the light emitted from the second field lens 128 is incident on the diffuser plate 122 and is uniformized by passing through the diffuser plate 122. From the uniformized light, image light to be displayed as a virtual image VI or a real image RI is generated by the TFT 123, and the uniformed light passes through the polarization switching element 124, which is switched by the control unit 15 to a conversion element for converting to P-polarized light or S-polarized light, and is then emitted from the PGU 10 as the first display light L1 or the second display light L2.

[0076] As described above, in the HUD device 1 according to this embodiment, the light distribution adjustment unit has one second field lens 128 equipped with an incident-side convex lens 128a and an exit-side convex lens 128b, and the second field lens 128 emits a plurality of first optical axes AX1 as parallel light as a first light distribution pattern from the exit-side convex lens 128b in response to the light emitted from the plurality of first light sources 11a that has entered through the incident-side convex lens 128a, and In response to the light emitted from the second light source 11b, multiple second optical axes AX2 are emitted from the exit-side convex lens 128b in a light distribution pattern that is narrower than the above-mentioned parallel light, which is the second light distribution pattern. Therefore, by appropriately setting the shapes of the entrance-side convex lens 128a and the exit-side convex lens 128b in the second field lens 128, it is possible, for example, to make the first optical axis AX1 a parallel light when viewing a virtual image VI, and to make the second optical axis AX2 a light distribution pattern that is narrower than the parallel light when viewing a real image RI. [Explanation of symbols]

[0077] AX1 1st optical axis AX2 2nd optical axis C center axis Ca vehicle CL,CR center axis DR Driver F Synthetic focus L1 1st display light L2 2nd display light VI Virtual Image RI real image WS Windshield X,Y center axis 1 HUD device 10 PGU 11 Light source 11a 1st light source 11b Second light source 12 Display section 13 Reflector 15 Control Unit 16 Case 17 Opening 18 Coverslips 111 PCB 121a First condenser lens 121b Second condenser lens 121c Third condenser lens 121dL third convex lens 121dR Third convex lens 122 Diffuser 123 TFT 124 Polarization switching element 125a First field lens 125aL First convex lens 125aR second convex lens 126 First lenticular lens 127 Second lenticular lens 128 Second Field Lens 128a Convex lens on the entrance side 128b Convex lens on the output side 131 1st Mirror 132 Second Mirror 133 Third Mirror 1311 4th mirror 1321 5th Mirror 1331 6th Mirror

Claims

1. A head-up display device having an emission port, and emitting display light from the emission port toward a light-transmitting member to allow a virtual image and a real image of a display image represented by the display light to be visually recognized, a plurality of first light sources for the virtual image; a plurality of second light sources for the real image; a display unit including a display element, and emitting first display light having a plurality of first optical axes corresponding to the light emitted from the plurality of first light sources, and second display light having a plurality of second optical axes corresponding to the light emitted from the plurality of second light sources; a reflecting section that reflects the first display light and the second display light emitted from the display section toward the light-transmitting member; a control unit that controls the plurality of first light sources to be turned on when the virtual image is to be viewed, and controls the plurality of second light sources to be turned on when the real image is to be viewed; a light distribution adjustment unit that sets the entire plurality of first optical axes to a first light distribution pattern when the control unit turns on the plurality of first light sources, and sets the entire plurality of second optical axes to a second light distribution pattern that is narrower in a light traveling direction than the first light distribution pattern when the control unit turns on the plurality of second light sources; A head-up display device comprising:

2. The light distribution adjustment unit is a first condenser lens having a plurality of convex lenses on the exit side; The first condenser lens is Each convex lens is arranged so that the corresponding first optical axis substantially coincides with the central axis passing through the apex of the convex lens, and the corresponding second optical axis is positioned offset from the central axis.

2. The head-up display device according to claim 1.

3. The plurality of second light sources are arranged with the central axis of the first condenser lens as a boundary, a plurality of one-side second light sources located on one side of the central axis of the corresponding convex lens; a plurality of other-side second light sources located on the other side of the central axis of the corresponding convex lens; 3. The head-up display device according to claim 2.

4. The plurality of first light sources and the plurality of second light sources are When one corresponding first light source and one corresponding second light source are taken as one pair, The first condenser lens is arranged so that the distance between the one first light source and the one second light source of a pair that is far from the central axis of the first condenser lens is greater than the distance between the one first light source and the one second light source of a pair that is close to the central axis of the first condenser lens.

4. The head-up display device according to claim 3.

5. The light distribution adjustment unit is a second condenser lens having a plurality of convex lenses on the exit side; The plurality of second light sources are Located on one side of a central axis passing through the vertex of the corresponding convex lens, The plurality of first light sources are Located on the other side of the central axis passing through the vertex of the corresponding convex lens 2. The head-up display device according to claim 1.

6. At least one of the plurality of first light sources and the plurality of second light sources is The light sources are arranged so that the distance between each light source and the corresponding central axis increases or decreases in stages.

6. The head-up display device according to claim 5.

7. The light distribution adjustment unit is a first field lens including a first convex lens and a second convex lens on the exit side; In the first convex lens, the corresponding second optical axis is located on one side of a central axis passing through the vertex of the first convex lens, and the corresponding first optical axis is located on the other side of the central axis passing through the vertex of the first convex lens, In the second convex lens, The corresponding second optical axis is located on the other side of the central axis passing through the apex of the second convex lens, and the corresponding first optical axis is located on the one side of the central axis passing through the apex of the second convex lens.

7. The head-up display device according to claim 6.

8. In the first convex lens, the corresponding first optical axis and the corresponding second optical axis are disposed at positions that are line-symmetric with each other about the central axis that passes through the vertex of the first convex lens, In the second convex lens, The corresponding first optical axis and second optical axis are arranged at positions that are symmetrical to each other with respect to the central axis that passes through the vertex of the second convex lens.

8. The head-up display device according to claim 7.

9. a third condenser lens disposed closer to the first light source and the second light source than the first field lens and including a plurality of third convex lenses on an exit side thereof; In the third condenser lens, Two of the third convex lenses are arranged on the incident side of the first convex lens of the first field lens, and two of the third convex lenses are arranged on the incident side of the second convex lens of the first field lens.

9. The head-up display device according to claim 8.

10. The light distribution adjustment unit is a second field lens having an entrance convex lens and an exit convex lens; The second field lens is In response to the light beams emitted from the plurality of first light sources and incident on the incident-side convex lens, the plurality of first optical axes are emitted from the exit-side convex lens as parallel light beams having the first light distribution pattern, In response to the light emitted from the plurality of second light sources incident on the incident-side convex lens, the plurality of second optical axes are emitted from the exit-side convex lens in a light distribution pattern that is narrower than the parallel light as the second light distribution pattern.

2. The head-up display device according to claim 1.

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