Head-up display device

Abstract

To provide a technique capable of appropriately forming a plurality of display regions each capable of displaying a virtual image, regarding a technique of a head-up display device (HUD device) to contribute to "3: Good-Health and Well-Being" of Sustainable Development Goals.SOLUTION: A HUD device comprises: an image formation unit PGU1; an optical element 15 that is provided in the image formation unit PGU1 in order to generate image light divided into two lights, which are first image light and second image light; a first folding mirror (M21) that reflects the first image light; a second folding mirror (M22) that reflects the second image light; and a mirror M1 that reflects the first image light from the first folding mirror and the second image light from the second folding mirror. The HUD device forms a first display region capable of displaying a first virtual image on the basis of the first image light from the mirror M1, and forms a second display region capable of displaying a second virtual image on the basis of the second image light from the mirror M1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a technology for a head-up display (HUD). [Background technology]

[0002] As a HUD device to be mounted on a vehicle or the like, an HUD device has been developed that forms multiple virtual images in front of the driver on a transparent member such as a windshield or a combiner (a dedicated display board) as seen from the driver's viewpoint.

[0003] An example of the prior art is Japanese Patent Laid-Open Publication No. 2016-14861 (Patent Document 1). Patent Document 1 describes that "a head-up display device capable of efficiently directing image light toward an observer with a simple configuration is provided" and that "the projection unit 10 emits projection light 200a representing a display image, the first reflection unit 21 reflects the projection light 200a emitted by the projection unit 10 toward the second reflection unit 24, the second reflection unit 24 reflects the projection light 200a reflected by the first reflection unit 21 toward the transmissive screen 30, and the transmissive screen 30 transmits and diffuses the projection light 200a reflected by the second reflection unit 24 to emit image light 100 toward the observer. The first reflection unit 21 and the second reflection unit 24 are rotated to adjust the angle of the optical axis of the projection light 200a incident on the transmissive screen 30, thereby adjusting the angle of the image light 100 emitted from the transmissive screen 30." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-14861 Summary of the Invention [Problem to be solved by the invention]

[0005] A conventional HUD device such as that in Patent Document 1 changes the direction of image light by rotating a mirror, thereby providing a virtual image according to the height position of the driver's (observer's) viewpoint.

[0006] An object of the present disclosure is to provide a technology for the HUD device that can suitably form multiple display regions in which virtual images can be displayed. The display regions are, in other words, the display regions, display areas, screens, etc. of the HUD. [Means for solving the problem]

[0007] A representative embodiment of the present disclosure has the following configuration: A head-up display device of the embodiment includes an image forming unit that emits image light, an optical element provided in the image forming unit that generates image light that is split into first image light and second image light, a first folding mirror that reflects the first image light, a second folding mirror that reflects the second image light, and an image projection unit that reflects the first image light from the first folding mirror and the second image light from the second folding mirror, and forms a first display region that is a first display area in which a first virtual image can be displayed based on the first image light from the image projection unit, and forms a second display region that is a second display area in which a second virtual image can be displayed based on the second image light from the image projection unit. [Effects of the Invention]

[0008] According to a representative embodiment of the present disclosure, the technology of the HUD device described above can be used to preferably form multiple display areas in which virtual images can be displayed. Problems, configurations, effects, etc. other than those described above will be described in the detailed description of the invention. [Brief explanation of the drawings]

[0009] [Figure 1] 1 shows an example of the configuration of a vehicle equipped with the HUD device of the first embodiment. [Figure 2] 2 shows an example of the configuration of the vehicle shown in FIG. 1, including the installation of a HUD device. [Figure 3]2 shows an example of the configuration of a video display unit and the like in the HUD device of the first embodiment. [Figure 4] 1 shows an example of the configuration of an image forming unit in the HUD device according to the first embodiment. [Figure 5] 1 shows a first configuration example of two display areas seen from the driver's viewpoint in the HUD device of the first embodiment. [Figure 6] 10 shows a second configuration example of two display areas seen from the driver's viewpoint in the HUD device of the first embodiment. [Figure 7] 1A and 1B are schematic explanatory diagrams relating to the optical path blocking function and the like in the HUD device of the first embodiment. [Figure 8] 1 shows an example of the mounting configuration of the mirror, dust cover, etc. of the image display unit in the HUD device of the first embodiment. [Figure 9] 2 is a schematic explanatory diagram showing temperature detection related to the light path blocking function in the HUD device of the first embodiment. FIG. [Figure 10] 1 shows an example of the configuration of sensors and the like for acquiring vehicle information in the HUD device of the first embodiment. [Figure 11] 2 shows an example of the configuration of functional blocks in the HUD device according to the first embodiment. [Figure 12] 1 shows an example of the mounting configuration of an image forming unit in the HUD device according to the first embodiment. [Figure 13] 10 shows an example of the configuration of a video display unit and the like in a HUD device according to a second embodiment. [Figure 14] 10 shows an example of the configuration of a video display unit and the like in a HUD device according to Modification 1A of Embodiment 1. [Figure 15] 10 shows an example of the configuration of a video display unit and the like in a HUD device according to Modification 1B of Embodiment 1. [Figure 16] 13 shows a configuration example of a video display unit and the like in a HUD device according to Modification 1C of Embodiment 1. [Figure 17] FIG. 10 is a schematic explanatory diagram relating to the optical path blocking function and the like in the HUD device according to Modification 1D of the first embodiment. [Figure 18] 10 shows a third example of the configuration of two display areas as seen from the driver's viewpoint in the HUD device of the first embodiment. [Figure 19] 10 shows a fourth example configuration of two display areas seen from the driver's viewpoint in the HUD device of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, identical parts are generally designated by the same reference numerals, and repeated explanations will be omitted. In the drawings, the representation of components may not represent their actual positions, sizes, shapes, ranges, etc., in order to facilitate understanding of the invention.

[0011] For the sake of explanation, when describing processing by a program, the program, function, processing unit, etc. may be described as the main body, but the main hardware body for these is a processor, or a controller, device, computer, system, etc. that is configured with the processor, etc. A computer executes processing according to a program read into memory using resources such as memory and communication interfaces as appropriate through the processor. This realizes predetermined functions, processing units, etc. A processor is configured, for example, with semiconductor devices such as a CPU / MPU or GPU. Processing is not limited to software program processing, but can also be implemented using dedicated circuits. Dedicated circuits such as FPGAs, ASICs, and CPLDs can be used.

[0012] The program may be pre-installed as data on the target computer, or may be distributed as data from a program source to the target computer. The program source may be a program distribution server on a communication network, or a non-transitory computer-readable storage medium such as a memory card or disk. The program may be composed of multiple modules. The computer system may be composed of multiple devices. The computer system may be composed of a client-server system, a cloud computing system, an IoT system, etc. Various data and information may be composed of structures such as tables and lists, for example, but are not limited to these. Expressions such as identification information, identifiers, IDs, names, and numbers are interchangeable.

[0013] <Solutions, etc.> The basic purpose and function of the HUD device of the embodiment is to form two virtual images corresponding to two display areas on the windshield in front of the driver as viewed from the driver's viewpoint. To achieve this configuration, the HUD device of the embodiment is devised with an optical system configuration including an image forming unit and mirrors. Specifically, as shown in FIG. 3 etc., an image forming unit PGU1, which is an image display device, two folding mirrors M21 and M22, and a concave mirror M1 are provided within an image display unit 200 of the HUD device 1.

[0014] The image forming unit PGU1 includes a light source and a display panel, and between the light source and the display panel, the display surface is divided into two predetermined regions, a first region r1 and a second region r2, of which an optical element 15 is arranged in the second region r2 and the optical element 15 is not arranged in the first region r1. As a result, the image forming unit PGU1 emits a first image light C1 from the corresponding first region r1 of the display panel based on light passing through the first region r1, and emits a second image light C2 from the corresponding second region r2 of the display panel based on light passing through the optical element 15 in the second region r2.

[0015] Furthermore, in the HUD device of the embodiment, two light beams, image light C1 and image light C2, from image forming unit PGU1 are reflected by two mirrors, M21 and M22, which are folding mirrors. Mirror M21 reflects image light C1, and mirror M22 reflects image light C2.

[0016] The image projection unit M1 then reflects the two image lights C1 and C2 from the two mirrors M21 and M22 toward the windshield 3. The image projection unit M1 of the present invention is a concave mirror. This forms two HUD display areas 5 (51, 52) corresponding to the two image lights C1 and C2 from the image forming unit PGU1. When viewed from the driver's viewpoint 6, a first virtual image V1 is formed in the first display area 51 and a second virtual image V2 is formed in the second display area 52 in front of the windshield 3.

[0017] For example, the first virtual image V1 of the first display area 51 is formed at a relatively farther and higher position than the second virtual image V2 of the second display area 52 when viewed from the driver's viewpoint 6, and the second virtual image V2 of the second display area 52 is formed at a relatively closer and lower position than the first virtual image V1 of the first display area 51. In order to design such a virtual image optical system and virtual image distance, the HUD device of the embodiment is designed so that the optical path of the first image light C1 has a longer optical distance inside the housing than the optical path of the second image light C2.

[0018] Specifically, the image display unit 200 reflects and returns the first image light C1 generated after passing through the first region r1 of the image forming unit PGU1 by the mirror M21 disposed farther away, and reflects and returns the second image light C2 generated after passing through the optical element 15 of the second region r2 of the image forming unit PGU1 by the mirror M21 disposed closer. Furthermore, in order to separate the two image lights C1 and C2 and direct them toward the two mirrors M21 and M22, the image forming unit PGU1 uses the optical element 15 of the second region r2 to make the emission direction of the second image light C2 different from the emission direction of the first image light C1.

[0019] Furthermore, optical adjustments including the optical distance and projection direction of the two image light beams C1 and C2 are performed by the optical element 15 in the second region r2 in the image forming unit PGU1. With the above-described configuration, the HUD device of the embodiment is configured so that the optical path of the first image light beam C1 has a longer optical distance than the optical path of the second image light beam C2.

[0020] <First Embodiment> 1 to 12, etc., a HUD device 1 according to the first embodiment will be described. The HUD device 1 according to the first embodiment is a HUD device mounted on a vehicle, and is an AR-HUD capable of displaying a virtual image using AR.

[0021] [vehicle] FIG. 1 shows a schematic configuration of a vehicle 2 equipped with an HUD device 1 according to a first embodiment. The vehicle 2 includes a control unit 100, which is a vehicle controller. The control unit 100 controls the running of the vehicle 2. The HUD device 1 communicates with the control unit 100 via an interface such as CAN or LIN. The control unit 100 and the HUD device 1 constitute an in-vehicle system of the vehicle 2. The HUD device 1 generates image light and projects it onto a transparent area of ​​a windshield 3. As a result, a display area 5, which is a display area, is formed in the transparent area of ​​the windshield 3, and a virtual image is displayed within the display area 5.

[0022] The control unit 100 controls the HUD device 1 via CAN signals or the like, thereby displaying video information as a virtual image in the display area 5. The control unit 100 acquires vehicle information 4 using various sensors, measurement devices, communication devices, etc., as shown in FIG. 10 , which will be described later. The HUD device 1 inputs and acquires the vehicle information 4, etc., from the control unit 100 via CAN signals or the like. The HUD device 1 generates video data based on the vehicle information 4, etc., and emits video light to display a virtual image in the display area 5.

[0023] In Figure 1 and other figures, (X, Y, Z) are used as coordinate systems and directions for the purpose of explanation. Figure 1 and other figures show a spatial coordinate system relative to vehicle 2. The Z axis and Z direction are the vertical direction, or in other words, the up-down direction or longitudinal direction. The X axis and X direction are the first horizontal direction, or in other words, the left-right direction or lateral direction. The Y axis and Y direction are the second horizontal direction perpendicular to the X axis, or in other words, the front-rear direction.

[0024] [Video display unit] FIG. 2 shows an example of an installation of the HUD device 1 of the first embodiment in the vehicle 2 of FIG. 1. FIG. 2 shows a schematic diagram of the vehicle 2 of FIG. 1 in the YZ plane as viewed from the X-axis direction. FIG. 2 shows the HUD device 1, particularly the image display unit 200, installed in a dashboard 70 of the vehicle 2. FIG. 2 shows a case in which a driver U1, seated as a user U1 in the driver's seat of the vehicle 2, views a virtual image 9 in a display area 5 ahead through a windshield 3. The image display unit 200 of the HUD device 1 includes an image display device 10, a mirror M2, and a concave mirror M1. The optical systems, including the image display device 10, the mirror M2, and the concave mirror M1, are arranged and fixed in a predetermined positional relationship within a housing.

[0025] Note that Figure 2 shows the basic configuration, and does not show the mirrors or two display areas as shown in Figure 3 described below. Instead, it shows a single image forming unit, i.e., a video display device 10, and a single display area 5, which will be described in more detail below.

[0026] A part of the housing has an opening arranged to match the opening 7 of the dashboard 70. A transparent member such as a dust cover 71 (FIG. 3) described later is provided in the opening. The image light of the HUD device 1 passes through the dust cover 71 of the opening and is emitted.

[0027] Image display device 10 forms an image on a display surface and emits image light. Mirror M2 is, for example, a folding mirror made of a flat mirror. Mirror M2 reflects the image light from image display device 10 toward concave mirror M1. Mirror M1 is a concave mirror that functions as an image projection unit that magnifies and reflects the image light from mirror M2 in a direction at a set angle. Concave mirror M1 is, for example, made of a free-form mirror or a mirror with an asymmetric shape about the optical axis. Concave mirror M1 is made of a mirror with concave reflective surfaces on the X-axis and Z-axis.

[0028] As shown in the figure, image light from image display device 10 is reflected by mirror M2 and concave mirror M1, and the reflected image light is emitted from opening 7 and projected onto the surface of windshield 3. The image light is reflected by the surface of windshield 3 and heads toward driver's viewpoint 6. As a result, when the driver looks forward (rearward along the Y axis) from viewpoint 6, a display area 5 of the HUD is formed on windshield 3, and a virtual image 9 can be seen within display area 5. Within display area 5, the virtual image 9 formed by the image light is displayed superimposed on the actual view ahead. Note that FIG. 2 illustrates display area 5 as a first display area 5A along the surface of windshield 3 and a second display area 5B formed forward of windshield 3, which correspond to each other.

[0029] In the case of AR (Augmented Reality), the virtual image 9 is image information that is superimposed and displayed according to the position of the target object. In the case of non-AR, the virtual image 9 is image information that is displayed independently at a predetermined position. Examples of image information that becomes the virtual image 9 include various types of information such as vehicle speed, navigation information, and alert information.

[0030] A camera 90 is also provided in the vehicle 2, for example, near the rearview mirror. The camera 90 may be an exterior camera that takes pictures outside the vehicle, or an interior camera that takes pictures inside the vehicle.

[0031] [HUD device] FIG. 3 is a schematic explanatory diagram showing the configuration of the image display unit 200 and the configuration of the display area 5 in the YZ plane as the configuration of the HUD device 1 of the first embodiment. As shown in FIG. 3, one feature of the first embodiment is that the HUD device 1 includes one image forming unit PGU1 including an optical element 15, two folding mirrors M21 and M22, and one concave mirror M1. The HUD device 1 uses the optical element 15 to generate two image light beams C1 and C2, which are respectively emitted in different directions, and the two image light beams C1 and C2 are reflected by the two mirrors M21 and M22 and then reflected by the common concave mirror M1. This forms two display areas 5 (51 and 52).

[0032] The video display unit 200 includes an image forming unit PGU1 as one picture generation unit within a housing 60. In other words, the image forming unit PGU1 is a video display device 10. The image forming unit PGU1 includes a light source device 11 and a liquid crystal display panel (LCD) 12 as an example of a display panel, which is a display device, arranged downstream of the light source device 11, in other words, on the output side. Between the light source device 11 and the LCD 12, an optical element 15 is arranged in a second region r2, and no optical element 15 is arranged in a first region r1.

[0033] Mirror M1 and mirrors M21 and M22 in FIG. 3 correspond to mirror M1 and mirror M2 in FIG. 2. In the Y-axis direction, mirrors M21 and M22 are arranged at positions on the front side (rear side of the vehicle or driver's side), and mirror M1 is arranged at a position on the rear side (front side of the vehicle). Mirror M21 is a first folding mirror, and mirror M22 is a second folding mirror. In the first embodiment, the two mirrors M21 and M22 are flat mirrors. Mirror M21 has a reflective surface sf21, and mirror M22 has a reflective surface sf22. Mirror M1 is a concave mirror and has a concave reflective surface sf5.

[0034] 3, image forming unit PGU1 emits first image light C1 from a first region r1 and emits second image light C2 from a second region r2. Image forming unit PGU1 is disposed at a predetermined position in front of mirrors M21 and M22 in the Y-axis direction and below mirrors M21 and M22 in the Z-axis direction, so as to reflect first image light C1 and second image light C2 by mirrors M21 and M22.

[0035] The first image light C1 and the second image light C2 emitted from the display surface sf1 of the image forming unit PGU1 have their projection direction and other properties optically adjusted by the action of the optical element 15, and the first image light C1 is incident on and reflected by the surface sf21 of the mirror M21, and the second image light C2 is incident on and reflected by the surface sf22 of the mirror M22.

[0036] The first image light C1 reflected from mirror M21 and the second image light C2 reflected from mirror M22 proceed toward mirror M1. Mirror M1 reflects the first image light C1 and the second image light C2 at one reflecting surface sf5. As will be described later, the areas irradiated with the first image light C1 and the second image light C2 on reflecting surface sf5 may be different. After being reflected by reflecting surface sf5 of mirror M1, the first image light C1 and the second image light C2 are each transmitted through dustproof covers 71 arranged corresponding to the openings and projected onto surface sf6 of the windshield 3.

[0037] These image lights C1 and C2 are reflected by the surface sf6 of the windshield 3 and proceed toward the driver's viewpoint 6. When looking ahead from the viewpoint 6, a first display area 51 is formed by the first image light C1 of the image forming unit PGU1, and a second display area 52 is formed by the second image light C2. When looking ahead from the viewpoint 6, the virtual images 9 of the display area 5 can be seen on the windshield 3: a first virtual image V1 of the first display area 51 formed by the first image light C1, and a second virtual image V2 of the second display area 52 formed by the second image light C2.

[0038] In the image forming unit PGU1, an optical element 15 is disposed in a predetermined position in the second region r2 between the light source device 11 and the LCD 12, particularly close to the rear side of the LCD 12 (or the image light incident side of the LCD 12). In the image forming unit PGU1, the light source device 11, the light source element 15, and the LCD 12 are fixed in a predetermined positional relationship. The optical element 15 is formed of a prism or a lens.

[0039] The HUD device 1 of the first embodiment has an optical system in which one mirror M1 is shared by the first image light C1 and the second image light C2. For this reason, the HUD device 1 performs optical adjustment using the optical element 15 of the image forming unit PGU1 and two mirrors M21 and M22. The optical adjustment is an adjustment related to the optical distance to the virtual image 9, the direction, the magnification, etc.

[0040] Note that various configurations regarding the arrangement of the optical element 15 of the image forming unit PGU1 are possible, not limited to the configuration example in Fig. 3. As a modified example, the optical element 15 may be arranged on the optical path behind the display surface sf1 of the LCD 12, which is the display panel.

[0041] Fig. 14 shows a YZ plane view of Modification 1A, which is a modification of Embodiment 1. In Fig. 14, optical element 15 is disposed near display surface sf1 of LCD 12 in second region r2 of image forming unit PGU1.

[0042] Various configuration examples are possible for designing and optically adjusting the optical distance and the like between the first display region 51 based on the first image light C1 and the second display region 52 based on the second image light C2 using the optical element 15, other lenses, etc. As a basic concept, a virtual image optical system is designed based on one of the optical paths of the first image light C1 and the second image light C2, and the other optical path is optically adjusted using the optical element 15, other lenses, etc. In the example of Fig. 3, the optical path of the first image light C1 is used as a reference, and the optical distance and direction of the optical path of the second image light C2 are optically adjusted by providing the optical element 15 in the second region r2 and not providing the optical element 15 in the first region r1.

[0043] As a modification of the first embodiment, a lens or the like for optical adjustment may be arranged on the optical path from the display surface sf1 of the image forming unit PGU1 to the mirrors M21 and M22 as another additional component.

[0044] Fig. 15 shows a YZ plane view of Modification 1B, which is a modification of Embodiment 1. In Fig. 15, on the optical path to mirrors M21 and M22 downstream of display surface sf1 of image forming unit PGU1 similar to Fig. 3, a first lens L1 is arranged on the optical path of first image light C1 in the first region r1, and a second lens L2 is arranged on the optical path of second image light C2 in the second region r2. In this way, lenses or the like for optical adjustment may be provided on both the optical path of first image light C1 and the optical path of second image light C2.

[0045] In this modification 1B, first, the directions and the like of the two image lights C1, C2 are optically adjusted by optical element 15, and then optical adjustment is also performed by subsequent lenses L1, L2. Optical adjustment by lenses L1, L2 includes adjustment of optical distance and the like. Also, in this modification 1B, as in embodiment 1, the directions of the two image lights C1, C2 are adjusted by optical element 15 so that they spread toward the two mirrors M21, M22, which makes it easy to arrange the two lenses L1, L2.

[0046] In another variant, the optical distance, etc. may be designed based on the optical path of one of the first image light C1 and the second image light C2 (e.g., image light C1), and a lens, etc. for optical adjustment (e.g., lens L2) may be provided only on the optical path of the other image light (e.g., image light C2).

[0047] In the HUD device 1 of the first embodiment, as shown in FIG. 3 and FIG. 4 described later, the effective area of ​​the display surface sf1 of the LCD 12 is divided into two regions: a first region r1 and a second region r2. A virtual image V1 of the first display region 51 is formed by first image light C1 from the first region r1, and a virtual image V2 of the second display region 52 is formed by second image light C2 from the second region r2. The second virtual image V2 of the second display region 52 based on the second image light C2 has a shorter virtual image distance than the first virtual image V1 of the first display region 51 based on the first image light C1. The optical element 15, located near the rear side of the LCD 12, bends the ray angle of the light source light from the light source device 11, thereby separating the optical path of the second image light C2 for the second display region 52 from that of the first image light C1.

[0048] When the optical element 15 is configured by a lens instead of a prism, the lens is disposed at a position decentered from the optical axis of the second image light C2.

[0049] The first image light C1 and the second image light C2 are reflected by different folding mirrors, mirror M21 and mirror M22. The positions and orientations of mirror M21 and mirror M22 are designed so that they reflect the first image light C1 and the second image light C2 toward a single shared concave mirror M1.

[0050] In the optical system design of the HUD device 1 of embodiment 1, the optical path of the first image light C1 for forming the virtual image V1 in the first display area 51 and the optical path of the second image light C2 for forming the virtual image V2 in the second display area 52 have a shorter optical path length and a shorter virtual image distance than the optical path of the first image light C1.

[0051] FIG. 3 shows an example of a design of two display regions 5 (51, 52) based on a virtual image optical system. The first display region 51 is formed rearward (toward the front of the vehicle) from the second display region 52 in the Y-axis direction, and is also formed above the second display region 52 in the Z-axis direction. The optical path and optical distance of the first image light C1 from the first region r1 of the image forming unit PGU1 are longer than the optical path and optical distance of the second image light C2 from the second region r2 of the image forming unit PGU2, due to a configuration in which the first image light C1 is reflected by the mirror M21. Therefore, the first display region 51 is formed rearward (toward the front of the vehicle) from the second display region 52 in the Y-axis direction. Furthermore, the position at which the first image light C1 is irradiated onto the mirror M1 is lower in the Z-axis direction than the position at which the second image light C2 is irradiated. Therefore, the first image light C1 projected from the mirror M1 onto the windshield 3 is positioned above the second image light C2. As a result, the first display area 51 is formed above the second display area 52 in the Z-axis direction.

[0052] 3 , the HUD device 1 of the first embodiment can form a layered display area 5 using two display areas 51 and 52, and can display virtual images 9 (V1 and V2) in the two display areas 51 and 52. The HUD device 1 of the first embodiment can appropriately display the virtual image V1 only in one of the first display areas 51, or can appropriately display the virtual image V2 only in the other of the second display areas 52, or can simultaneously display the virtual images V1 and V2 in both of the display areas 51 and 52.

[0053] In the design example of the display area 5 and virtual image optical system in FIG. 3, the first display area 51 and the second display area 52 are arranged so that they partially overlap in the vertical direction corresponding to the Z axis when viewed from viewpoint 6 (FIG. 5 described later). That is, when viewed from viewpoint 6, a portion of the lower side of the first display area 51 overlaps with a portion of the upper side of the second display area 52. However, the first display area 51 and the second display area 52 may be arranged so that they are separated in the vertical direction corresponding to the Z axis when viewed from viewpoint 6 (FIG. 6 described later).

[0054] By adjusting the design of the optical system, for example, by adjusting the shape, position, and orientation of the optical element 15 of the image forming unit PGU1, and the positions and orientations of the two mirrors M21 and M22, the positional relationship of the virtual images 9 of the two display areas 5 can be realized.

[0055] [Polarization design] In FIG. 3, the first image light C1 and the second image light C2 projected onto the surface sf6 of the windshield 3 in the HUD device 1 of the first embodiment have the following polarization characteristics: The first image light C1 is light that is incident on the surface sf6 of the windshield 3 as S-polarized light (also referred to as first polarization). The second image light C2 is light that is similarly incident on the surface sf6 of the windshield 3 as S-polarized light (first polarization). Note that in the drawings, S-polarized light may be indicated as (S) and P-polarized light may be indicated as (P). S-polarized light (or S-wave) is light whose electric field oscillates in a direction perpendicular to the plane of incidence, and S stands for axial. P-polarized light (or P-wave) is light whose electric field oscillates within the plane of incidence, and P stands for parallel. The first polarization and the second polarization are linearly polarized light that are orthogonal to each other.

[0056] In accordance with this design, the image forming unit PGU1 is an image display device that generates and emits a first image light C1 that is S-polarized light and a second image light C1 that is S-polarized light.

[0057] The following modification may also be mentioned. The vibration direction characteristics, i.e., the S-polarized and P-polarized characteristics, of the first image light C1 and the second image light C2 from the image forming unit PGU1 may be reversed. In this case, the virtual image V1 of the first display area 51 and the virtual image V2 of the second display area 52 are formed by the P-polarized image light.

[0058] [Image formation unit] Fig. 4 shows a perspective view of an example configuration of image forming unit PGU1 including optical element 15 of Fig. 3. In addition to the spatial coordinate system (X, Y, Z), Fig. 4 also shows a coordinate system (x, y, z) based on display surface sf1 of LCD 12 of image forming unit PGU1. The x-axis direction is the horizontal direction within the screen on display surface sf1 (in other words, the lateral direction), the y-axis direction is the vertical direction within the screen on display surface sf1 (in other words, the longitudinal direction), and the z-axis direction is the direction perpendicular to the xy plane formed by these directions.

[0059] In the space connecting the xy plane on the emission side of light source device 11 and the xy plane on the incidence side of LCD 12, the illustrated dashed line serves as the boundary to divide the space into two regions, which will be referred to as a first region r1 and a second region r2 for the sake of explanation. The first region r1 and the second region r2 on the xy plane on the emission side of light source device 11 are each illustrated as a dashed rectangle, and the first region r1 and the second region r2 on display surface sf1, which is the xy plane on the emission side of LCD 12, are each illustrated as a dashed rectangle.

[0060] The optical element 15 is disposed in a second region r2 in a space connecting the xy plane on the emission side of the light source device 11 and the xy plane on the incidence side of the LCD 12. In this example, the optical element 15 is configured by a prism having a roughly triangular prism shape as shown in the figure. The axis of the triangular prism shape of the optical element 15 is disposed along the x-axis direction, corresponding to the horizontal side of the LCD 12. The cross section (yz plane) of the triangular prism shape of the optical element 15 has a roughly right-angled triangle as shown in the figure, for example. One side of the right triangle that forms a right angle is disposed close to the xy plane on the rear side of the LCD 12, and the hypotenuse side that does not form a right angle is disposed facing the emission surface sf11 of the light source device 11.

[0061] The light source device 11 emits light from the emission surface sf11 in the z-axis direction. The light source light from the first region r1 of the light source device 11 is incident on the rear side of the LCD 12 without passing through the optical element 15, as indicated by one of the dashed-dotted arrows. The LCD 12 uses the light source light from the first region r1 as backlight and emits a first video light C1 based on an image to be displayed in the first region r1 on the display surface sf1. On the other hand, the light source light from the second region r2 of the light source device 11 is incident on the rear side of the LCD 12 via the optical element 15, as indicated by the other dashed-dotted arrow. The LCD 12 uses the light source light from the second region r2 as backlight and emits a second video light C2 based on an image to be displayed in the second region r2 on the display surface sf1.

[0062] The first image light C1 emitted from the first region r1 on the display surface sf1 has an optical axis along the z-axis direction. The second image light C2 emitted from the second region r2 on the display surface sf1 has an optical axis tilted upward at a predetermined angle θ with respect to the z-axis direction. As a result, the first image light C1 and the second image light C2 travel along optical paths that split and diverge toward the two mirrors M21 and M22.

[0063] It should be noted that a diffusion plate or the like may be further provided in the space behind the light source device 11 and before the position of the optical element 15 .

[0064] [HUD display area] 5, corresponding to FIG. 3, shows a schematic configuration in the XZ plane of the display area 5 (51, 52) formed by the image display unit 200 of the HUD device 1 of the first embodiment when the windshield 3 is viewed forward (in the Y-axis direction) from the driver's viewpoint 6. FIG. 5 schematically shows a case where two display areas 51, 52 are formed by image light (the image light C1, C2 described above) reflected and projected from the concave mirror M1 onto the windshield 3. FIG. 5 particularly shows a case where the two display areas 51, 52 are formed so as to partially overlap each other in the vertical direction (in the Z-axis direction) when viewed from the viewpoint 6.

[0065] In the effective area of ​​the reflecting surface sf5 of the concave mirror M1, a part of the lower side has an area 401 that is irradiated with the first image light C1 from the mirror M21, and a part of the upper side has an area 402 that is irradiated with the second image light C2 from the mirror M22. The first image light C1 reflected from the area 401 forms a first display area 51 on the upper side, and the second image light C2 reflected from the area 402 forms a second display area 52 on the lower side.

[0066] 5, in the effective area of ​​the reflecting surface sf5 of the concave mirror M1, the area 401 where the first image light C1 is reflected and the area 402 where the second image light C2 is reflected partially overlap. Note that, as shown in Fig. 3, there is an inversion relationship of images via the mirrors M1, M21, M22, etc., so that the first image light C1 from the lower area 401 on the reflecting surface sf5 of the mirror M1 forms a virtual image V1 of the upper first display area 51, and the second image light C2 from the upper area 402 forms a virtual image V2 of the lower second display area 52.

[0067] FIG. 6 shows a modified example of the formation of the display area 5, particularly a case where two display areas 51, 52 are formed separated in the vertical direction (Z-axis direction) without overlapping when viewed from viewpoint 6. In the effective area of ​​the reflecting surface sf5 of the concave mirror M1, a region 401 irradiated with the first image light C1 is provided on a part of the lower side, and a region 402 irradiated with the second image light C2 is provided on a part of the upper side. The first display area 51 is formed by the first image light C1 from region 401, and the second display area 52 is formed by the second image light C2 from region 402. In the configuration example of FIG. 6, in the effective area of ​​the reflecting surface sf5 of the concave mirror M1, the region 401 reflecting the first image light C1 and the region 402 reflecting the second image light C2 are separated.

[0068] 5 and other figures, in the HUD device 1 of the first embodiment, the components for reflecting the two image light beams C1 and C2 from one image forming unit PGU1 are shared as one concave mirror M1. The configuration of the irradiation area of ​​the two image light beams C1 and C2 in the effective area of ​​the reflecting surface sf5 of the concave mirror M1 is not limited to the configuration examples shown in FIGS. 5 and 6, and variations will be described later.

[0069] [Solar power countermeasures] The HUD device 1 of the first embodiment also has the following features for countering sunlight, etc. The functions and structures related to the countermeasures against sunlight are configured by combining a polarizing element and an infrared (IR) cut as described below.

[0070] First, an example of the configuration of the polarizing element is as follows. In Fig. 3, dustproof cover 71 provided at the opening of housing 60 is made of transparent plastic, and an absorptive polarizing element is provided on the surface of the transparent plastic. The absorption axis of this absorptive polarizing element is perpendicular to the image light (first image light C1 and second image light C2).

[0071] In addition, a reflective polarizing element or an absorptive polarizing element is provided as an optical element immediately behind the display surface sf1 of the LCD 12 in the image forming unit PGU1. The reflective polarizing element has a reflection axis perpendicular to the image light (first image light C1 and second image light C2). The absorptive polarizing element has an absorption axis perpendicular to the image light (first image light C1 and second image light C2).

[0072] Fig. 16 shows a configuration example of the polarizing element as Modification Example 1C. In the example of Fig. 16, an absorptive polarizing element is disposed as optical element 16 immediately behind display surface sf1 of LCD 12. This absorptive polarizing element absorbs components of first image light C1 and second image light C2 other than S-polarized light.

[0073] As a modification of the polarizing element, the display surface sf1 of the LCD 12 may be divided into a first region r1 and a second region r2, and a polarizing element may be disposed in each region.

[0074] An example of a configuration related to IR blocking is as follows: First, an IR absorbing function is provided to the dustproof cover 71. For example, an IR absorbing sheet is provided as one layer on the dustproof cover 71.

[0075] Furthermore, mirrors M21 and M22 are cold mirrors. A cold mirror is a mirror that transmits infrared light and reflects visible light. The visible light reflected by the cold mirrors is first image light C1 and second image light C2.

[0076] In a configuration without sunlight protection, if external light such as sunlight enters the housing 60 through the dustproof cover 71 at the opening, the incident external light may be reflected by the concave mirror M1 and may then be incident on the display surface sf1 of the image forming unit PGU1. In this case, external light entering the surface of the LCD 12, which is the display panel, can undesirably cause panel burn-in. For this reason, the first embodiment has the functions and structure for sunlight protection as described above.

[0077] In FIG. 16, consider the case where external light, such as sunlight, passes through the dust cover 71 and enters the housing 60 in the opposite direction to the image light C1 and C2. The IR component of this external light is first filtered out by the dust cover 71's IR absorption function. The external light is reflected by the concave mirror M1, and some of the reflected external light may be further reflected by mirrors M21 and M22. In this case, the cold mirrors M21 and M22 filter out the IR component of the incident external light. Some of the external light reflected by mirrors M21 and M22 may further travel toward the image forming unit PGU1 and strike the display surface sf1. In this case, the optical element 16, a reflective polarizing element or an absorptive polarizing element disposed on the front side of the LCD 12, reflects or absorbs the external light. This reduces the amount of external light that reaches the display surface sf1 of the LCD 12. This prevents or reduces panel burn and other issues on the LCD 12.

[0078] [About the optical path blocking function and protection mode] FIG. 7 is a schematic explanatory diagram of the light path blocking function (i.e., the function of preventing external light from entering) and the protection mode of the image display unit 200 of the HUD device 1 according to the first embodiment, shown in the YZ plane, similar to FIG. 3 . Based on the configuration of the image forming unit PGU1 and mirrors M21, M22, and M1 shown in FIG. 3 , the HUD device 1 according to the first embodiment further includes a light path blocking function related to sunlight protection. This light path blocking function blocks the entry of external light, such as sunlight, on the optical path from the dust cover 71 to the image forming unit PGU1, thereby preventing external light from entering the display surface sf1 of the LCD 12. This function redirects the light path of external light by rotating the mirror M1 according to a control mode (sometimes referred to as a protection mode, etc.), thereby preventing external light from entering the display surface sf1 of the image forming unit PGU1. In other words, it changes the direction of the light path of external light. This function prevents panel burn and other problems on the LCD 12.

[0079] In FIG. 7, the concave mirror M1 is provided with a drive mechanism 61 including a rotation axis and a motor. The rotation axis of the drive mechanism 61 is an axis extending in the X-axis direction corresponding to the left-right direction of the vehicle, and the concave mirror M1 can rotate around this rotation axis by driving a motor or the like connected to the rotation axis. By rotating the concave mirror M1 with this drive mechanism 61, the orientation of the concave mirror M1 can be changed. In the first embodiment, the mechanism that can rotate the mirror M1 can be used in common with a mechanism that adjusts the formation position of the display area 5 in the up-down direction 5a (FIG. 5, etc.).

[0080] First, in the normal display mode, the HUD device 1 sets the concave mirror M1 to State A, indicated by the dashed line. In State A, the optical axes of the image lights C1 and C2 for the respective display areas 51 and 52 are as indicated by the dashed-line arrows. Consider the incident optical path of external light, which is opposite to the direction of the optical axes of the image lights C1 and C2, in the normal display mode. External light a100, which is sunlight a100 indicated by the dashed arrow in the figure, indicates the optical axis of this incident optical path of external light. External light a101 indicates the optical path of external light in the opposite direction to the optical path of the first image light C1, and external light a102 indicates the optical path of external light in the opposite direction to the optical path of the second image light C2. When external light a100 (a101, a102), which is sunlight on this incident optical path of external light, passes through the dustproof cover 71 and enters the housing 60, it is reflected by the mirror M1 and travels in the opposite direction to the optical paths of the image lights C1 and C2. The external light is reflected by the mirrors M21 and M22, travels toward the image forming unit PGU1, and is incident on the display surface sf1. This can cause panel burn in the LCD 12, so measures must be taken to prevent this.

[0081] The HUD device 1 of the first embodiment has a function of switching from a normal display mode to a protection mode, which is a function for blocking the optical path of external light a100 incident on the image forming unit PGU1 as shown in the figure. In the protection mode, the HUD device 1 of the first embodiment rotates the mirror M1 based on the drive mechanism 61 to state B shown by the solid line. The mirror M1 is rotated from state A to state B by a predetermined angle around the rotation axis in the Y-axis direction toward the front (rear of the vehicle).

[0082] As a result, in the protected mode, external light a101 and external light a102, which are sunlight a100 entering the housing 60 through the dustproof cover 71, are reflected by the mirror M1 in state B and then travel as external light a103 and external light a104. The direction of the optical path of external light a103 based on external light a101 is deviated so as not to strike the surface sf21 of the mirror M21 (FIG. 3). The direction of the optical path of external light a104 based on external light a102 is deviated so as not to strike the surface sf22 of the mirror M22 (FIG. 3).

[0083] More specifically, the optical path of external light a103 is directed downward in the Z-axis direction relative to the surface sf21 of mirror M21 (FIG. 3). This external light a103 is not reflected by mirror M22 and therefore does not strike the display surface sf1 of image forming unit PGU1. Furthermore, the optical path of external light a104 is directed downward in the Z-axis direction relative to the surface sf22 of mirror M22 (FIG. 3). The optical path of external light a104 strikes the surface sf21 of mirror M21 (FIG. 3), which is behind and below mirror M22. However, the optical path of external light a105, which is obtained after external light a104 is reflected by mirror M21, is directed downward in the Z-axis direction relative to the display surface sf1 of image forming unit PGU1. In other words, the optical path of external light a105 based on external light a102 is also directed away from the surface sf1 of image forming unit PGU1 so as not to strike the display surface sf1 of image forming unit PGU1.

[0084] As described above, in the protection mode, the HUD device 1 of the first embodiment is controlled so that the direction of the optical path of reflected external light is changed in accordance with the rotation of the concave mirror M1 so that external light is not incident on the display surface sf1 of the image forming unit PGU1. This protects the panel surface of the image forming unit PGU1, particularly the LCD 12, from deterioration.

[0085] The mechanism for changing the direction of the optical path of external light in response to the rotation of mirror M1, in other words, the mechanism for blocking external light from entering image forming unit PGU1, is not limited to the configuration example shown in Fig. 7. Any configuration is possible as long as the optical path direction is changed so that external light a103, a104 reflected from concave mirror M1 does not ultimately enter display surface sf1 of image forming unit PGU1, regardless of whether it is irradiated onto mirror M21 or mirror M22.

[0086] FIG. 17 shows a modification 1D of the first embodiment, which is related to the optical path blocking function. In this modification 1D, the two mirrors M21 and M22 are arranged with a wider gap in the Z-axis direction compared to the configuration example of FIG. 7. Corresponding to the arrangement of these mirrors M21 and M22, the two image lights C1 and C2 from the display surface sf1 of the image forming unit PGU1 are designed to have a larger difference in direction angle using optical element 15. In this modification 1D, when the concave mirror M1 is set to state B in the protection mode, the optical path directions of external light a103 and external light a104 reflected by the concave mirror M1 based on the incidence of external light a100 (a101, a102) are deviated so that they do not strike the mirrors M21 and M22, respectively.

[0087] Specifically, the optical path of external light a103 based on external light a101 is directed toward a position below mirror M21. The optical path of external light a104 based on external light a102 is directed toward a position below mirror M22, particularly toward the space between mirror M22 and mirror M21. Unlike in FIG. 7, the optical path of external light a104 does not even hit mirror M21. As a result, even in modification 1D, external light can be prevented from entering display surface sf1 of image forming unit PGU1 in protection mode.

[0088] In addition, in the first embodiment, the rotation direction of the mirror M1 is set to a direction tilting from the rear to the front in the Y-axis direction as shown in FIG. 7 , thereby shifting the optical axis direction of external light reflected from the concave mirror M1 downward relative to the respective mirrors M21 and M22, such as external light a103 and external light a104. However, this is not limiting. In a modified example, the rotation direction of the mirror M1 may be set to a direction tilting from the front to the rear-front, thereby shifting the optical axis direction of external light reflected from the concave mirror M1 upward relative to the respective mirrors M21 and M22. However, in this case, the reflecting surface sf5 of the mirror M1 faces upward, which may generate stray light into the vehicle 2, which is undesirable. Therefore, in the first embodiment, the rotation direction of the mirror M1 is set to a direction tilting forward, as described above.

[0089] As described above, the HUD device 1 controls the mirror M1 to be in the first state (state A) in the normal display mode and in the second state (state B) in the protection mode. Control such as switching to the protection mode can be performed in the following two ways. In the first case, the HUD device 1 is in the protection mode when not in use or when the virtual image 9 is not displayed, and in the normal display mode when the virtual image 9 is displayed. Furthermore, even when the ignition switch of the vehicle 2 is in the OFF state, the HUD device 1 is in the protection mode and blocks the external light incident optical path to protect the image forming unit PGU1.

[0090] In the second case, the HUD device 1 detects incident external light based on a sensor even in the normal display mode, as will be described later, and if it determines that incident external light should be avoided from a temperature perspective, it automatically switches to the protection mode. This control is performed by prioritizing avoidance of incident external light and prevention of panel burnout over displaying the virtual image 9.

[0091] [Implementation example] 8 shows an example of the mounting of the housing 60, the image forming unit PGU1, the mirror M21, the mirror M1, the dust cover 71, etc. in the video display unit 200. Note that in FIG. 8, of the two mirrors M21 and M22, only one mirror M21 is shown, and the other mirror M22 is not shown.

[0092] 8, a solar radiation sensor 66 is provided near the dust cover 71. The solar radiation sensor 66 detects the incidence of external light such as sunlight a100 within a detection range such as a range 66a.

[0093] [Temperature detection unit and sunlight countermeasures] Fig. 9 is a schematic explanatory diagram of temperature control using the solar radiation sensor 66 and the like, which is related to the light path blocking function and protection mode of Fig. 7. As will be described later (Fig. 11), the control unit 101 of the HUD device 1 also includes a protection processing unit 1060, which performs temperature detection and protection processing using detection information from the solar radiation sensor 66 of Fig. 8. Fig. 9 shows an example of the processing content by the protection processing unit 1060. Fig. 9 mainly illustrates the image forming unit PGU1 extracted from Figs. 3 and 7, and simply illustrates the dust cover 71, solar radiation sensor 66, mirror M1, etc.

[0094] 9, image forming unit PGU1 is configured to include light source device 11 and LCD 12, which is a display device. In normal display mode, external light a100, which is sunlight a100, is reflected by concave mirror M1 and becomes external light a901 and external light a902. External light a901 is reflected by mirror M21 and becomes external light a903, and external light a902 is reflected by mirror M22 and becomes external light a904. External light a903 and external light a904 are directed toward display surface sf1 of LCD 12 of image forming unit PGU1.

[0095] First, the temperature (TP1) of the LCD 12 provided in the image forming unit PGU1 can be estimated from the ambient temperature Ta of the image forming unit PGU1, the temperature rise ΔT(I) due to external light a910 (a903, a904) incident on the LCD 12, and the temperature rise ΔT(L) due to thermal radiation from the light source device 11.

[0096] For simplicity, it can be assumed that the ambient temperature Ta, the amount of temperature rise ΔT(I), the amount of temperature rise ΔT(L), etc. are similar in the first region r1 and the second region r2 of the image forming unit PGU1, and the temperature TP1 of the LCD 12 in each region can be estimated using a similar mechanism. In detail, it is also possible to assume that the ambient temperature Ta, the amount of temperature rise ΔT(I), the amount of temperature rise ΔT(L), etc. are different between the first region r1 and the second region r2 of the image forming unit PGU1, and estimate the temperature of the LCD 12 in each region.

[0097] 11 of the HUD device 1 performs the following process. First, the ambient temperature Ta of the image forming unit PGU1 can be detected by a temperature sensor installed in the HUD device 1 or a temperature sensor 912 (FIG. 10) installed in the vehicle 2. The protection processing unit 1060 determines the ambient temperature Ta of the image forming unit PGU1 based on the information detected by the temperature sensor.

[0098] Next, the temperature rise ΔT(I) due to sunlight a100 can be calculated based on the sunlight intensity detected by the sunlight sensor 66. The protection processing unit 1060 calculates the temperature rise ΔT(I) due to external light a910 of the image forming unit PGU1 based on the detection information of the sunlight sensor 66.

[0099] Next, the temperature rise ΔT(L) caused by heat radiation from the light source device 11 can be calculated based on the brightness or light amount of the backlight set in the light source device 11, for example, the duty ratio of pulse width modulation (PWM) control by the light source drive unit 1022. The protection processing unit 1060 calculates the temperature rise ΔT(L) caused by heat radiation from the light source device 11 of the image forming unit PGU1.

[0100] In the control example of the first embodiment, the formula for calculating the temperature rise ΔT(I) on the LCD 12 side is set individually depending on the difference between the first region r1 and the second region r2. The respective formulas are shown as formulas G1 and G2. As a modified example and a simple configuration, the same formula may be used to calculate the temperature rise ΔT(I) in the first region r1 and the second region r2 of the image forming unit PGU1.

[0101] As described above, the protection processing unit 1060 indirectly detects the temperature TP1 of the display surface of the LCD 12 by calculation using the ambient temperature Ta of the image forming unit PGU1, the temperature rise ΔT(I) of the LCD 12 due to sunlight, and the temperature rise ΔT(L) from the light source device 11.

[0102] Here, the temperature rise ΔT(L) due to heat radiation from light source device 11 is a parameter that can be controlled by the brightness or light intensity of the backlight. In other words, there is a predetermined relationship between the brightness or light intensity of the backlight of light source device 11 and the temperature of LCD 12, and it can be said that the temperature of LCD 12 can be adjusted by adjusting the brightness or light intensity of the backlight of light source device 11.

[0103] For this reason, the control unit 101 of the HUD device 1 performs control to adjust the brightness or light intensity of the backlight of the light source device 11 in accordance with the temperature TP1 of the LCD 12 detected by the protection processing unit 1060. For example, the control unit 101 compares the detected temperature TP1 of the LCD 12 with a predetermined threshold value, and adjusts the brightness or light intensity of the backlight of the light source device 11 if the temperature exceeds the threshold value. For example, if the detected temperature TP1 exceeds a predetermined threshold value Th1, the control unit 101 controls the light source device 11 to lower the brightness or light intensity of the backlight, i.e., to lower the duty ratio of the PWM control. This makes it possible to suppress a rise in temperature of the LCD 12 in the image forming unit GPU1.

[0104] [Vehicle information and sensors] FIG. 10 shows an example of the configuration of sensors and the like used by the vehicle information acquisition unit 1015 (FIG. 11) of the HUD device 1 or the control unit 100 of the vehicle 2 to acquire the vehicle information 4 of FIG. 1. FIG. 10 shows examples of various sensors, in other words, information acquisition devices, measurement devices, communication devices, and the like, connected to the vehicle information acquisition unit 1015 or the control unit 100. For example, the control unit 100 acquires the vehicle information 4 from sensors and the like installed in various parts of the vehicle 2. The various sensors periodically detect parameter values ​​related to conditions such as driving conditions inside and outside the vehicle 2. Furthermore, the control unit 100 determines and detects various events related to the vehicle 2 based on the information detected by the sensors.

[0105] Vehicle information 4 is a general term for information related to the driving status of the vehicle 2. The vehicle information 4 includes ADAS information and the like. The vehicle information 4 includes, for example, the speed information and gear information of the vehicle 2, steering angle information, lamp illumination information, external light information, distance information, infrared information, engine ON / OFF information, camera image information, acceleration gyro information, GPS (Global Positioning System) information, navigation information, vehicle-to-vehicle communication information, and road-to-vehicle communication information. The camera image information includes in-vehicle camera image information and outside-vehicle camera image information. The GPS information includes current time information, latitude and longitude information.

[0106] 10, various sensors include a vehicle speed sensor 901, a shift position sensor 902, a steering wheel steering angle sensor 903, a headlight sensor 904, an illuminance sensor 905, a chromaticity sensor 906, a distance measurement sensor 907, an infrared sensor 908, an engine start sensor 909, an acceleration sensor 910, a gyro sensor 911, a temperature sensor 912, a wireless transceiver for road-to-vehicle communication 913, a wireless transceiver for vehicle-to-vehicle communication 914, an in-vehicle camera 915, an outside-vehicle camera 916, a GPS receiver 917, and a VICS (Vehicle Information and Communication System, registered trademark) receiver 918. The various sensors are not limited to these, and can be added, deleted, replaced, etc.

[0107] The vehicle speed sensor 901 detects the speed of the vehicle 2 (also referred to as vehicle speed) and generates speed information as the detection result. The shift position sensor 902 detects the current gear and generates gear information as the detection result. The steering wheel angle sensor 903 detects the current steering wheel angle and generates steering wheel angle information as the detection result. The headlight sensor 904 detects whether the headlights are on / off, etc. and generates lamp illumination information as the detection result. The illuminance sensor 905 and chromaticity sensor 906 detect external light and generate external light information as the detection result.

[0108] The distance measurement sensor 907 detects the distance between the vehicle 2 and an external object, and generates distance information that represents the detection result. The infrared sensor 908 detects the presence and distance of an object in the vicinity of the vehicle 2, and generates infrared information that represents the detection result. The engine start sensor 909 detects whether the engine is on or off, and generates on or off information that represents the detection result. The acceleration sensor 910 and gyro sensor 911 detect the acceleration and angular velocity of the vehicle 2, and generate acceleration gyro information that represents the attitude and behavior of the vehicle 2 as the detection result. The temperature sensor 912 detects the temperature inside and outside the vehicle 2, and generates temperature information that represents the detection result.

[0109] The in-vehicle camera 915 captures images of the interior of the vehicle 2 to generate in-vehicle camera video information. The exterior camera 916 captures images of the exterior of the vehicle 2 to generate outside camera video information. In a specific example, the camera 90 in FIG. 2 corresponds to the in-vehicle camera 915 and the exterior camera 916. The in-vehicle camera 915 captures, for example, the driver's posture, eye position, and movement, constituting a DMS (Driver Monitoring System). By analyzing the in-vehicle camera video information, it is possible to grasp the driver's fatigue level and line of sight. The exterior camera 916 also captures images of the surrounding conditions, such as the area ahead of the vehicle 2. By analyzing the exterior camera video information, it is possible to grasp the presence or absence of other vehicles or people around the vehicle 2, buildings, terrain, road conditions such as rain, snow, ice, and unevenness, and road signs. The exterior camera 916 also includes a drive recorder that records video of the driving situation.

[0110] The road-to-vehicle communication wireless transceiver 913 generates road-to-vehicle communication information through road-to-vehicle communication between the vehicle 2 and roads, signs, traffic lights, etc. The vehicle-to-vehicle communication wireless transceiver 914 generates vehicle-to-vehicle communication information through vehicle-to-vehicle communication between the vehicle 2 and other vehicles in the vicinity. The GPS receiver 917 generates GPS information by receiving GPS signals from GPS satellites. For example, the current time, latitude, and longitude can be acquired as GPS information. The VICS receiver 918 generates VICS information obtained by receiving VICS signals. The GPS receiver 917 and the VICS receiver 918 may be provided as part of a navigation system.

[0111] [Function Block] Fig. 11 shows an example of the configuration of the functional blocks of the HUD device 1. In the example configuration of Fig. 11, a display driver 1021, a light source drive unit 1022, etc. are provided in correspondence with the configuration of the image forming unit PGU1 and the concave mirror M1 as shown in Fig. 3. In addition, in this example configuration, a video processing unit 1013 is provided which is connected to the display driver 1021 and the light source drive unit 1022.

[0112] 11, the HUD device 1 includes a control unit 101, an image display unit 200, a mirror driving unit 1020, a display driver 1021, a light source driving unit 1022, an audio driver 1025, an audio output device 1041, an audio input device 1042, etc. The control unit 101 includes an MCU (microcontrol unit) 1010, a non-volatile memory 1011, a volatile memory 1012, an image processing unit 1013, an audio processing unit 1014, a vehicle information acquisition unit 1015, a communication unit 1016, an operation input unit 1017, a protection processing unit 1060, etc. These units are interconnected via a bus or the like, and are capable of inputting, outputting, and communicating with each other.

[0113] The control unit 101 is, in other words, a controller or control device. The control unit 101 realizes control functions and the like based on processing by a processor. The control functions are functions for controlling the entire HUD device 1 and each component, and include a function for displaying a virtual image 9 in the display area 5. The control unit 101 realizes its functions by software program processing or a dedicated circuit.

[0114] The storage unit of the HUD device 1 is configured to include a non-volatile memory 1011 and a volatile memory 1012. The storage unit stores various types of data and information, including computer programs, that are handled by the control unit 101 and the like.

[0115] The communication unit 103 is a device equipped with a communication interface. The communication unit 103 is connected to and capable of communicating with the control unit 100 (for example, an electronic control unit (ECU)) via an interface such as a CAN (Controller Area Network) or a LIN (Local Interconnect Network) of the vehicle 2.

[0116] The mirror driving unit 1020 is a device that drives the driving mechanism 61 of the concave mirror M1 under the control of the control unit 101.

[0117] The display driver 1021 is a device including a drive circuit that drives the LCD 12 of the image forming unit PGU1 under the control of the control unit 101.

[0118] The light source driving unit 1022 is a device including a driving circuit and the like that drives the light source device 11 of the image forming unit PGU1 based on control from the control unit 101. The light source driving unit 1022 has a driving circuit and the like that can change the on / off and light intensity of the light emission of each light source element of the light source device 11.

[0119] The audio input device 1042 is composed of a microphone, a circuit, etc. The audio output device 1041 is composed of a speaker, a circuit, etc. Although the case where the HUD device 1 is provided with the audio input device 1042 and the audio output device 1041 is shown, the present invention is not limited to this, and the HUD device 1 may use the audio input device 1042 and the audio output device 1041 that are externally connected to the inside of the vehicle 2 (for example, the control unit 100).

[0120] The control unit 101 in FIG. 11 acquires input information such as the vehicle information 4 ( FIG. 1 ), ADAS information, and event information through the vehicle information acquisition unit 1015. Alternatively, the control unit 101 acquires input information such as the vehicle information 4 ( FIG. 1 ), ADAS information, and event information as a CAN signal from the control unit 100 through the communication unit 103. The vehicle information acquisition unit 1015 may be integrated with the communication unit 103. The input information includes detection signals from various sensors as shown in FIG. 10 , or information resulting from processing the detection signals by the control unit 100. The input information also includes, for example, information about objects in a real scene detected based on an image from the camera 90, as well as alert information and navigation information to be superimposed on the objects. The control unit 101, using its control function, generates video data and video information to be displayed as a virtual image 9 in the display area 5 as necessary based on the input information. The control unit 101 generates video signals and the like for controlling a display driver 1021 and the like based on the video data and video information.

[0121] The control unit 101 may also acquire operation input information from a user through the operation input unit 1017. Examples of the operation input unit 1017 include a remote control. When audio is to be output by the HUD device 1, the control unit 101 generates audio output information and controls the audio driver 1025. When inputting the voice of a user such as a driver, the control unit 101 performs voice recognition based on the input voice of the audio input device 1042 and accepts predetermined instructions, etc.

[0122] 11, the HUD device 1 may be provided with various sensors, including, for example, a solar radiation sensor 66 (FIG. 8). The control unit 101 may use the detection information of the sensors to determine and detect the state of the HUD device 1 and the state near the HUD device 1, and perform predetermined control.

[0123] 11 may be mounted inside the housing 60 of the video display unit 200 in FIG. 3 or may be connected to the outside of the housing 60. In addition, the components such as the control unit 101 in FIG.

[0124] [Video display control example] 11 , the control unit 101 generates video data for displaying a virtual image 9 in the display area 5 based on input information such as vehicle information 4 and input video data. For example, the HUD device 1 determines to display an AR navigation image or an alert image as a first virtual image V1 in the first display area 51, and to display non-AR distance information, vehicle speed information, or the like as a second virtual image V2 in the second display area 52. To this end, the control unit 101 generates first video data whose output destination is the first area r1 of the LCD 12 of the image forming unit PGU1, and second video data whose output destination is the second area r2.

[0125] Based on the video data of the display source, the control unit 101 performs distortion correction taking into account differences in the curvature of the windshield 3, and adjusts the on / off and light intensity of the light source. Based on the video data, the control unit 101 drives and controls the display driver 1021 and the light source drive unit 1022. The display driver 1021 drives the LCD 12 based on a signal from the control unit 101. The light source drive unit 1022 drives the light source device 11 based on a signal from the control unit 101. As a result, images are formed in the first region r1 and the second region r2 on the display surface sf1 of the LCD 12. The image forming unit PGU1 emits first video light C1 based on the light source light from the light source device 11 and the image formed in the first region r1 of the LCD 12, and emits second video light C2 based on the light source light from the light source device 11 and the image formed in the second region r2 of the LCD 12.

[0126] 11 performs processing corresponding to the control of switching between the normal display mode and the protection mode based on the detection information of the solar radiation sensor 66, as described above.

[0127] [Image formation unit configuration example] The following are examples of mounting configurations of the image forming unit GPU1, which is the video display device 10. Fig. 12 shows an example of mounting configuration of the image forming unit PGU1. The image forming unit PGU1 in Fig. 12 includes a light source device 11 and an LCD 12. The light source device 11 is configured to include an LED board 201, LED elements 202, a reflector 203, a heat sink 204, a polarization conversion element 205, a light guide 206, a diffuser 206, etc. These components of the light source device 11 are fixed to a case, and are configured as a light source module.

[0128] A plurality of LED elements 202 are arranged on the LED substrate 201. Fig. 12 shows only one LED element 202 and a reflector 203. The LED element 202 is an example of a semiconductor light source element. The reflector 203 is a collimator that reflects the diffused light emitted from the LED element 202 so as to change the direction of the light and converts it into approximately parallel light. The heat sink 204 dissipates heat and cools the LED substrate 201.

[0129] The polarization conversion element 205 receives the substantially parallel light from the reflector 203, performs polarization conversion on the light so as to align the polarization characteristics, and emits the substantially parallel light after polarization conversion to the light guide 206. The polarization conversion element 205 is configured by combining, for example, a polarization conversion prism and a wavelength plate. In the first embodiment, the polarization conversion by the polarization conversion element 205 in the image forming unit PGU1 is polarization conversion for aligning the light to polarization perpendicular to the absorption axis of the incident-side polarizer of the LCD 12.

[0130] The light guide 206 reflects substantially parallel light in a first direction from the polarization conversion element 205 into the reflecting portion, which then reflects the light in a second direction. The second direction is toward the LCD 12. As shown in the partially enlarged view, the reflecting portion of the light guide 206 has a plurality of reflecting surfaces 206a and a plurality of connecting surfaces 206b, and the reflecting surfaces 206a and the connecting surfaces 206b are arranged alternately. The reflecting portion of the light guide 206 also achieves predetermined light distribution control. Each of the plurality of reflecting surfaces 206a has an inclination so as to achieve a reflection direction corresponding to the predetermined light distribution control.

[0131] The light in the second direction after being reflected by the reflecting portion of the light guide 206 is incident on the diffuser 207 and diffused by the diffuser 207. The panel of the LCD 12 is disposed above the diffuser 207, with the aforementioned optical element 15 interposed therebetween. A drive circuit board and the like are connected to the panel of the LCD 12 via a flexible cable. The panel of the LCD 12 receives light from the diffuser 207 from the rear side and uses the light as backlight to emit image lights C1 and C2 from the display surface sf1 on the front side. In the first region r1, the first image light C1 is generated based on the light source light that does not pass through the optical element 15. In the second region r2, the second image light C2 is generated based on the light source light that passes through the optical element 15. These image lights C1 and C2 are light beams that have the aforementioned S-polarized light and have directivity in a specific direction.

[0132] [Effects of the First Embodiment] As described above, the HUD device 1 of the first embodiment can suitably form two display areas 5 (51, 52) in which the virtual images 9 can be displayed, particularly layered display areas. This allows the HUD device 1 to use the two display areas 5 (51, 52) to provide the driver U1 with various virtual images 9 for driving assistance and the like, thereby contributing to safe driving.

[0133] <Embodiment 2> The HUD device of the second embodiment will be described using Figures 13 and onward. The following mainly describes the components of the second embodiment that are different from those of the first embodiment. In the second embodiment, of the two mirrors M21 and M22 mentioned above, the lower mirror M21 in the Z-axis direction is configured as a concave mirror 1301. The first image light C1 reflected by this concave mirror 1301 is first imaged at a predetermined point P1 and then incident on the concave mirror M1. The point P1 at which the image is formed on the mirror M21 is located near the mirror M22. In a specific example, the point P1 is located at a predetermined position below the mirror M22 in the Z-axis direction. By using the optical system in which the image is formed by the concave mirror 1301 in this way, the image forming unit PGU1 and the mirror M21 can be disposed closer to the concave mirror M1 and the mirror M22. With this configuration, the HUD device 1 of the second embodiment can further reduce the size of the image display unit 200.

[0134] In the second embodiment, as described above, the optical system forms an image by using the concave mirror 1301 along the optical path of the first image light C1. Therefore, the image drawn in the first region r1 and the image drawn in the second region r2 on the display surface sf1 of the LCD 12, which is the image source, are vertically inverted. The first image light C1 from the first region r1 is reflected by the concave mirror 1301 to become the upside-down image light C1, which then enters the concave mirror M1. The second image light C2 from the second region r2 that passes through the optical element 15 is reflected by the mirror M22, which is a plane mirror, and then enters the concave mirror M1, as in the first embodiment. The image light C1 and C2 reflected by the concave mirror M1 form virtual images 9 (V1, V2) of the two display regions 5 (51, 52) on the windshield 3, as in the first embodiment. The virtual image V1 of the first display area 51 and the virtual image V2 of the second display area 52 are images that are vertically aligned when viewed from the driver's viewpoint 6.

[0135] [Solar power countermeasures] The configuration for countering sunlight in the HUD device 1 of the second embodiment is as follows. This configuration is the same as the configuration for countering sunlight in the first embodiment described above, and is configured by combining a polarizing element and an IR cut as described below.

[0136] First, an example of the configuration of the polarizing element is as follows. In Fig. 13, the dustproof cover 71 provided at the opening of the image display unit 200 is made of transparent plastic, and an absorptive polarizing element is provided on the surface of the transparent plastic. The absorption axis of this absorptive polarizing element is perpendicular to the image light (first image light C1 and second image light C2).

[0137] In addition, a reflective polarizing element or an absorptive polarizing element is provided as an optical element immediately behind the display surface sf1 of the LCD 12 in the image forming unit PGU1. The reflective polarizing element has a reflection axis perpendicular to the image light (first image light C1 and second image light C2). The absorptive polarizing element has an absorption axis perpendicular to the image light (first image light C1 and second image light C2).

[0138] 13 also shows a configuration example of the polarizing element. In this example, an absorptive polarizing element is disposed as the optical element 16 immediately behind the display surface sf1 of the LCD 12. This absorptive polarizing element absorbs components of the first image light C1 and the second image light C2 other than S-polarized light.

[0139] As a modification of the polarizing element, the display surface sf1 of the LCD 12 may be divided into a first region r1 and a second region r2, and a polarizing element may be disposed in each region.

[0140] An example of a configuration related to IR blocking is as follows. First, the dustproof cover 71 is provided with an IR absorbing function. For example, an IR absorbing sheet is provided as one layer on the dustproof cover 71. Furthermore, the mirrors M21 and M22, which are the concave mirror 1301, are configured as cold mirrors.

[0141] In FIG. 13, consider the case where external light, such as sunlight, passes through the dust cover 71 and enters the housing 60 in the opposite direction to the image light C1 and C2. The IR component of this external light is first filtered out by the dust cover 71's IR absorption function. The external light is reflected by the concave mirror M1, and some of the reflected external light may be further reflected by mirrors M21 and M22. In this case, the cold mirrors M21 and M22 filter out the IR component of the incident external light. Some of the external light reflected by mirrors M21 and M22 may further travel toward the image forming unit PGU1 and be incident on the display surface sf1. In this case, the optical element 16 on the front side of the LCD 12 reflects or absorbs the external light. This reduces the amount of external light that reaches the display surface sf1 of the LCD 12. This prevents or reduces panel burn on the LCD 12.

[0142] As a modification of the second embodiment, the characteristics of the S-polarized light and the P-polarized light may be reversed in the first image light C1 and the second image light C2 from the image forming unit PGU1.

[0143] [Effects of the second embodiment] As described above, according to the HUD device 1 of the second embodiment, in addition to the effect that the two display areas 5 (51, 52) can be suitably formed as in the first embodiment, the image display unit 200 can be made smaller.

[0144] [Relationship between the effective area of ​​a concave mirror and the display area] In the first embodiment and the like, various configurations are possible for the relationship between the effective area on the reflecting surface sf5 of the concave mirror M1 onto which the two image light beams C1 and C2 are irradiated and the positions at which the two display regions 5 (51 and 52) are formed, and a supplementary explanation will be provided below. Two configuration examples are shown in the above-mentioned Figures 5 and 6, but the present invention is not limited to these. Modified examples are shown in Figures 18 and 19. Figure 18 shows a third configuration example, and Figure 19 shows a fourth configuration example.

[0145] 18, in the concave mirror M1, the two effective areas corresponding to the two image lights C1 and C2 are formed as separate regions 401 and 402. In contrast, depending on the details of the design of the optical system, etc., the two display regions 5 (51 and 52) are formed to overlap when viewed from the viewpoint 6. The details of the design of the optical system include the design of the position and orientation of the image forming units, the design of the shapes of each mirror M21, M22, and M1, the design of the reflection direction of each image light, etc.

[0146] 19, in the concave mirror M1, the two effective areas of the two image lights C1 and C2 are formed to overlap as regions 401 and 402. In contrast, depending on the details of the design of the optical system, etc., the two display regions 5 (51 and 52) are formed to be separate when viewed from the viewpoint 6.

[0147] The present invention has been specifically described above based on the embodiments, but the present invention is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit of the invention. In each embodiment, components can be added, deleted, or replaced, except for essential components. Unless otherwise specified, each component may be singular or plural. A combination of each embodiment is also possible.

[0148] As described above, when the technology according to the embodiment is used, the effective area of ​​the display panel corresponding to the image light from the light source device is divided into a first region and a second region, and a virtual image of the first display region is formed by the first image light from the first region, and a virtual image of the second display region is formed by the second image light from the second region. By providing a technology that can form two virtual images corresponding to the two display regions forward on the windshield as viewed from the driver's perspective, it is possible to provide the driver with various virtual images for driving assistance and to provide an information display device (head-up display device) that contributes to safe driving, etc. This makes it possible to prevent traffic accidents. Furthermore, it is possible to contribute to "Good health and well-being" of the Sustainable Development Goals (SDGs) advocated by the United Nations. [Explanation of symbols]

[0149] 1...HUD device, 2...vehicle, 3...windshield, 4...vehicle information, 5, 51, 52...display region (display area), 6...viewpoint, 7...opening, 8...steering wheel, 9, V1, V2...virtual image, 10...image display device, 15...optical element, 60...housing, 71...dustproof cover, 200...image display unit, PGU1...image forming unit, M1, M21, M22...mirror, C1, C2...image light, r1...first region, r2...second region.

Claims

1. an image forming unit that emits image light; an optical element provided in the image forming unit for generating image light that is split into two, a first image light and a second image light, as the image light; a first folding mirror that reflects the first image light; a second folding mirror that reflects the second image light; an image projection unit that reflects the first image light from the first folding mirror and the second image light from the second folding mirror; Equipped with forming a first display region, which is a first display area in which a first virtual image can be displayed, based on the first image light from the image projection unit; forming a second display region that is a second display area in which a second virtual image can be displayed based on the second image light from the image projection unit; the first folding mirror is a concave mirror, the second folding mirror is composed of a plane mirror, the first image light is reflected by the concave mirror, and then formed into an image at a predetermined image position, and then incident on the image projection unit; Head-up display device.

2. The head-up display device according to claim 1, the image forming unit includes a light source device and a display panel that generates the image light based on light source light from the light source device; the optical element is disposed on the rear side or the front side of the display panel in a position corresponding to the second area of ​​a display surface of the display panel, the display surface being divided into a first area and a second area; the first image light is emitted from the first region, and the second image light is emitted from the second region; Head-up display device.

3. The head-up display device according to claim 1, The first display area and the second display area are formed forward of the transparent member as seen from the viewpoint of the driver of the vehicle, and are separated or overlapped in the vertical direction. Head-up display device.

4. The head-up display device according to claim 1, The first display area and the second display area are formed in such a way that the first display area is disposed forward of the transparent member as viewed from the viewpoint of the driver of the vehicle, and the first display area is disposed relatively farther away than the second display area in the front-to-rear direction. Head-up display device.

5. The head-up display device according to claim 1, the image projection unit is configured by a mirror, and an area on a reflective surface thereof where the first image light is irradiated and an area on which the second image light is irradiated are separated or overlapped; Head-up display device.

6. The head-up display device according to claim 1, the image projection unit is configured with a mirror and has a drive mechanism that rotates around a rotation axis that extends in the horizontal direction; In the protection mode in the normal display mode, the mirror is rotated, and when external light is incident on the mirror in a direction opposite to the direction of the image light, the direction of the external light from the mirror to the first folding mirror and the second folding mirror is changed so that the external light reflected by the mirror does not enter the display surface of the image forming unit. Head-up display device.

7. 7. The head-up display device according to claim 6, A solar radiation sensor or a temperature sensor is provided, When the incidence of the external light is detected based on the detection information of the solar radiation sensor or the temperature sensor, the normal display mode is switched to the protection mode. Head-up display device.

8. The head-up display device according to claim 1, the image forming unit includes a light source device and a display panel that generates the image light based on light source light from the light source device; a reflective polarizing element or an absorptive polarizing element is disposed on the front side of the display panel of the image forming unit; Head-up display device.

Images