Head-up display device

Abstract

Regarding head-up display (HUD) technology, this invention provides a technology that can suitably form multiple display areas on which virtual images can be displayed. According to this invention, it contributes to Sustainable Development Goal 3, "Good Health and Well-being for All." [Solution] The HUD device comprises an image forming unit PGU1, an optical element 15 provided on the image forming unit PGU1 for generating image light divided into two parts, a first image light and a 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. Based on the first image light from the mirror M1, a first display area on which a first virtual image can be displayed is formed, and based on the second image light from the mirror M1, a second display area on which a second virtual image can be displayed is formed.

Description

Technical Field

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[0001] The present invention relates to the technology of a head-up display (HUD) device.

Background Art

[0002] As a HUD device mounted on a vehicle or the like, a HUD device has been developed that forms a plurality of virtual images in front of a transmissive member such as a windshield or a combiner (a dedicated display panel) as viewed from the driver's perspective.

[0003] As a prior art example, Japanese Patent Application Laid-Open No. 2016-14861 (Patent Document 1) can be cited. Patent Document 1 states that "a head-up display device is provided that has a simple configuration and can efficiently direct image light toward an observer," and that "the projection unit 10 emits projection light 200a indicating 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 emits image light 100 that is diffusely transmitted through the projection light 200a reflected by the second reflection unit 24 toward the observer. By rotating the first reflection unit 21 and the second reflection unit 24 to adjust the angle of the optical axis of the projection light 200a incident on the transmissive screen 30, the angle of the image light 100 emitted from the transmissive screen 30 is adjusted."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional HUD devices, such as those described in Patent Document 1, change the direction of the image light by rotating a mirror, thereby providing a virtual image that corresponds to the height position of the driver's (observer's) viewpoint.

[0006] The purpose of this disclosure is to provide a technology for the above-mentioned HUD device that can suitably form multiple display areas on which a virtual image can be displayed. In other words, a display area refers to the display area, display area, or screen of the HUD. [Means for solving the problem]

[0007] A typical embodiment of this disclosure has the following configuration. The head-up display device of the embodiment includes an image forming unit that draws an image on a display panel and emits image light; an optical element provided in the image forming unit for generating image light that is divided into two parts, a first image light and a second image light; a first virtual image optical system that projects the first image light to display a first virtual image; and a second virtual image optical system that projects the second image light to display a second virtual image. In this embodiment, a first image is drawn in a first region of the display panel from which the first image light is emitted, and a second image is drawn in a second region of the display panel from which the second image light is emitted. The orientations of the first image and the second image are inverted vertically from each other, and the orientations of the first virtual image and the second virtual image displayed by the first virtual image optical system and the second virtual image optical system are the same. [Effects of the Invention]

[0008] According to a representative embodiment of this disclosure, the technology of the HUD device described above allows for the suitability of forming multiple display areas on which virtual images can be displayed. Other issues, configurations, and effects are shown in the embodiments for carrying out the invention. [Brief explanation of the drawing]

[0009] [Figure 1] An example of the configuration of a vehicle equipped with the HUD device of Embodiment 1 is shown. [Figure 2] Figure 1 shows an example of the configuration, including the installation of a HUD device, in the vehicle. [Figure 3] This shows an example of the configuration of the video display unit and other components in the HUD device of Embodiment 1. [Figure 4] An example of the configuration of the image forming unit in the HUD device of Embodiment 1 is shown. [Figure 5] The first configuration example of the HUD device of Embodiment 1 shows the two display areas as seen from the driver's perspective. [Figure 6] The HUD device of Embodiment 1 shows a second configuration example of the two display areas as seen from the driver's perspective. [Figure 7] A schematic diagram illustrating the optical path blocking function and other features of the HUD device according to Embodiment 1 is shown. [Figure 8] The HUD device of Embodiment 1 shows an example of the implementation configuration of the mirror and dust cover of the video display unit. [Figure 9] A schematic diagram illustrating the temperature detection related to the optical path blocking function in the HUD device of Embodiment 1 is shown. [Figure 10] This shows an example configuration of sensors and other components for acquiring vehicle information in the HUD device of Embodiment 1. [Figure 11] An example of the configuration of a functional block in the HUD device of Embodiment 1 is shown. [Figure 12] This shows an example of the implementation configuration of the image forming unit in the HUD device of Embodiment 1. [Figure 13] An example of the configuration of the video display unit and other components in the HUD device of Embodiment 2 is shown. [Figure 14] This shows an example of the configuration of a video display unit and the like in a HUD device of Modification 1A of Embodiment 1. [Figure 15] This shows an example of the configuration of a video display unit and the like in a HUD device of Modification 1B of Embodiment 1. [Figure 16] This shows an example of the configuration of a video display unit and the like in a HUD device of Modification 1C of Embodiment 1. [Figure 17] This is a schematic diagram illustrating the optical path blocking function and other features of a HUD device according to a modified example 1D of Embodiment 1. [Figure 18]The third configuration example of the two display areas as seen from the driver's perspective in the HUD device of Embodiment 1 is shown. [Figure 19] The fourth configuration example of the two display areas as seen from the driver's perspective in the HUD device of Embodiment 1 is shown.

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same components are generally denoted by the same reference numerals, and repeated descriptions are omitted. In the drawings, the representation of components may not represent the actual position, size, shape, range, etc. in order to facilitate understanding of the invention.

[0011] For the sake of explanation, when describing the processing by a program, the program, function, processing unit, etc. may be mainly described. However, the hardware entity for them is a processor, or a controller, device, computer, system, etc. composed of such a processor. The computer executes processing according to the program read onto the memory while appropriately using resources such as a memory and a communication interface by the processor. Thereby, a predetermined function, processing unit, etc. are realized. The processor is composed of semiconductor devices such as a CPU / MPU, GPU, etc. The processing is not limited to software program processing and can also be implemented by a dedicated circuit. Applicable dedicated circuits include FPGA, ASIC, CPLD, etc.

[0012] The program may be pre-installed as data in the target computer, or may be distributed as data from the program source to the target computer. The program source may be a program distribution server on a communication network, or may be a non-transitory computer-readable storage medium, such as a memory card or a disk. The program may be composed of a plurality of modules. The computer system may be composed of a plurality of devices. The computer system may be composed of a client-server system, a cloud computing system, an IoT system, etc. Various data and information are composed in a structure such as a table or a list for example, but are not limited to this. Expressions such as identification information, identifier, ID, name, number, etc. are mutually replaceable.

[0013] <Means for solving problems, etc.> As a basic purpose and function, the HUD device of the embodiment can form two virtual images corresponding to two display areas in front of the windshield as viewed from the driver's perspective. In order to realize such a configuration, the HUD device of the embodiment devises the configuration of an optical system such as an image forming unit and a mirror. Specifically, as shown in FIG. 3 and the like, in the video display unit 200 of the HUD device 1, an image forming unit PGU1 which is a video display device, two folding mirrors M21 and M22, and a concave mirror M1 are provided.

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

[0015] Furthermore, the HUD device of this embodiment reflects two video beams C1 and C2 from the image forming unit PGU1 using two mirrors M21 and M22, which are folding mirrors. Mirror M21 reflects video beam C1, and mirror M22 reflects video beam C2.

[0016] The image projection unit M1 then reflects two image lights C1 and C2 from the two mirrors M21 and M22 toward the windshield 3. The image projection unit M1 of this invention is a concave mirror. As a result, two HUD display areas 5 (51, 52) corresponding to the two image lights C1 and C2 from the image forming unit PGU1 are formed. 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, facing forward relative to the windshield 3.

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

[0018] Specifically, the image display unit 200 reflects the first image light C1, which is generated after passing through the first region r1 of the image forming unit PGU1, back by the mirror M21 that is positioned further away, and reflects the second image light C2, which is generated after passing through the optical element 15 of the second region r2 of the image forming unit PGU1, back by the mirror M21 that is positioned 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 direction of emission of the second image light C2 different from the direction of emission of the first image light C1.

[0019] Furthermore, the optical element 15 in the second region r2 of the image forming unit PGU1 performs optical adjustments, including the optical distance and projection direction of the two image beams C1 and C2. In this embodiment, the HUD device is configured such that the optical path of the first image beam C1 has a longer optical distance than the optical path of the second image beam C2.

[0020] <Embodiment 1> The HUD device 1 of Embodiment 1 will be described using Figures 1 to 12, etc. The HUD device 1 of Embodiment 1 is a HUD device mounted on a vehicle and is an AR-HUD capable of displaying virtual images using augmented reality.

[0021] [vehicle] Figure 1 shows the schematic configuration of a vehicle 2 equipped with the HUD device 1 of Embodiment 1. The vehicle 2 is equipped with a control unit 100, which is a vehicle controller. The control unit 100 controls the driving of the vehicle 2. The HUD device 1 communicates with the control unit 100 through an interface such as CAN or LIN. The control unit 100 and the HUD device 1 constitute the in-vehicle system of the vehicle 2. The HUD device 1 generates image light and projects it onto the transparent area of ​​the windshield 3. As a result, a display area 5 is formed on 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, etc., to display video information as a virtual image in the display area 5. The control unit 100 acquires vehicle information 4 using various sensors, measuring devices, communication devices, etc., as shown in Figure 10 below. The HUD device 1 receives and acquires the vehicle information 4, etc., from the control unit 100 via CAN signals, etc. The HUD device 1 generates video data based on the vehicle information 4, etc., and displays a virtual image in the display area 5 by emitting video light.

[0023] Note that in Figure 1 and other diagrams, (X, Y, Z) is used as the coordinate system and direction for explanatory purposes. In Figure 1 and other diagrams, the spatial coordinate system is shown relative to vehicle 2. The Z axis and Z direction are vertical directions, or in other words, up and down directions. The X axis and X direction are the first horizontal directions, or in other words, left and right directions. The Y axis and Y direction are the second horizontal directions perpendicular to the X axis, or in other words, front and back directions.

[0024] [Video display unit] Figure 2 shows an example of the mounting of the HUD device 1 of Embodiment 1 in the vehicle 2 of Figure 1. Figure 2 shows a schematic diagram of the vehicle 2 of Figure 1 in the YZ plane as viewed from the X axis direction. In Figure 2, the HUD device 1, in particular the video display unit 200, is mounted in the dashboard 70 of the vehicle 2. Figure 2 shows a case where a driver U1, as user U1, is seated in the driver's seat of the vehicle 2 and views the virtual image 9 in the display area 5 forward through the windshield 3. The video display unit 200 of the HUD device 1 comprises a video display device 10, a mirror M2, and a concave mirror M1. The optical system, including the video display device 10, the mirror M2, and the concave mirror M1, is arranged and fixed in a predetermined positional relationship within the housing.

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

[0026] A portion of the housing has an opening that is positioned to match the opening 7 of the dashboard 70. A transparent member such as a dust cover 71 (Figure 3), described later, is provided in this opening. The video light from the HUD device 1 is emitted by passing through the dust cover 71, etc., in the opening.

[0027] The video display device 10 forms an image on its display surface and emits video light. Mirror M2 is, for example, a folding mirror made of a planar mirror. Mirror M2 reflects the video light from the video display device 10 toward the concave mirror M1. Mirror M1 is a concave mirror and functions as a video projection unit that magnifies and reflects the video light from mirror M2 toward a set angle. The concave mirror M1 is composed of, for example, a free-form surface mirror or a mirror with an asymmetrical optical axis shape. The concave mirror M1 is composed of a mirror having concave reflective surfaces in the X and Z axes.

[0028] As shown in the figure, the video light from the video display device 10 is reflected by the mirror M2 and the concave mirror M1, and the reflected video light is emitted from the opening 7 and projected onto the surface of the windshield 3. This video light is reflected from the surface of the windshield 3 and directed towards the driver's viewpoint 6. As a result, when the driver looks forward (rear along the Y-axis) from the driver's viewpoint 6, a display area 5 of the HUD is formed on the windshield 3, and a virtual image 9 can be seen within the display area 5. Within the display area 5, the virtual image 9 formed by the video light is displayed superimposed on the actual scene in front. Note that in Figure 2, the display area 5 is shown as a first display area 5A along the surface of the windshield 3 and a second display area 5B formed in front of the windshield 3, and these correspond to each other.

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

[0030] Vehicle 2 also has a camera 90 installed, for example, near the rearview mirror. Camera 90 includes an exterior camera that takes pictures of the outside of the vehicle and an interior camera that takes pictures of the inside of the vehicle.

[0031] [HUD device] Figure 3 is a schematic explanatory diagram showing the configuration of the video display unit 200 and the display area 5 in the YZ plane as the configuration of the HUD device 1 of Embodiment 1. As shown in Figure 3, one of the features of Embodiment 1 is that it comprises 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 video beams C1 and C2 using the image forming unit PGU1 and emit them in their respective directions. These two video beams C1 and C2 are reflected by the two mirrors M21 and M22 and then reflected by the common concave mirror M1. As a result, two display areas 5 (51, 52) are formed.

[0032] The video display unit 200 includes a picture generation unit (PGU1) within the housing 60. The picture generation unit PGU1 is, in other words, a video display device 10. The picture generation unit PGU1 includes a light source device 11 and a liquid crystal display panel (LCD) 12, which is an example of a display panel that is located 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 the second region r2, but no optical element 15 is arranged in the first region r1.

[0033] Mirrors M1 and M21, M22 in Figure 3 correspond to mirrors M1 and M2 in Figure 2. In the Y-axis direction, mirrors M21 and M22 are positioned at the front (rear of the vehicle or driver's side), and mirror M1 is positioned at the rear (front of the vehicle) side. Mirror M21 is a first folding mirror, and mirror M22 is a second folding mirror. In Embodiment 1, the two mirrors M21 and M22 are planar 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] In Figure 3, the image forming unit PGU1 emits a first image light C1 from a first region r1 and a second image light C2 from a second region r2. The image forming unit PGU1 is positioned at a predetermined location relative to mirrors M21 and M22, on the front side of the vehicle in the Y-axis direction and below the mirrors M21 and M22, in order to reflect the first image light C1 and the 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 parameters optically adjusted by the action of the optical element 15. The first image light C1 is incident on the surface sf21 of mirror M21 and reflected, while the second image light C2 is incident on the surface sf22 of mirror M22 and reflected.

[0036] The first image light C1 reflected from mirror M21 and the second image light C2 reflected from mirror M22 are directed toward mirror M1. Mirror M1 reflects both the first image light C1 and the second image light C2 on one reflective surface sf5. As will be described later, the areas illuminated by the first image light C1 and the second image light C2 on the reflective surface sf5 may be different. After being reflected by the reflective surface sf5 of mirror M1, the first image light C1 and the second image light C2 are projected onto the surface sf6 of the windshield 3, respectively, by passing through the dust cover 71 positioned corresponding to the opening.

[0037] These image light beams C1 and C2 are reflected off the surface sf6 of the windshield 3 and directed toward the driver's viewpoint 6. Looking forward from viewpoint 6, the first image light beam C1 of the image forming unit PGU1 forms the first display area 51, and the second image light beam C2 forms the second display area 52. Looking forward from viewpoint 6, the virtual images 9 of the display area 5 that can be seen on the windshield 3 are the first virtual image V1 of the first display area 51 formed by the first image light beam C1, and the second virtual image V2 of the second display area 52 formed by the second image light beam C2.

[0038] In the image forming unit PGU1, the optical element 15 is positioned in a predetermined location in a second region r2 between the light source device 11 and the LCD 12, particularly close to the back side of the LCD 12 (or the side where the image light of the LCD 12 is incident). 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 composed of a prism or a lens.

[0039] The HUD device 1 of Embodiment 1 has an optical system that shares one mirror M1 for the first image light C1 and the second image light C2. For this purpose, the HUD device 1 performs optical adjustment using the optical element 15 of the image forming unit PGU1 and two mirrors M21 and M22. Optical adjustment is an adjustment related to the optical distance, direction, and magnification to the virtual image 9.

[0040] It should be noted that various configurations are possible for the arrangement of the optical elements 15 in the image forming unit PGU1, not limited to the configuration example shown in Figure 3. As a modification, the optical elements 15 may be arranged in the optical path behind the display surface sf1 of the LCD 12, which is the display panel.

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

[0042] For the design and optical adjustment of the optical distance, etc., in the first display area 51 by the first image light C1 and the second display area 52 by the second image light C2, various configurations are possible using optical elements 15 and other lenses. The basic idea is that the 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 optical elements 15 and other lenses. In the example in Figure 3, the optical distance and direction of the optical path of the second image light C2 are optically adjusted by not providing optical elements 15 in the first area r1 and providing optical elements 15 in the second area r2, with the optical path of the first image light C1 as the reference.

[0043] As a modification of Embodiment 1, other additional components may be placed in the optical path from the display surface sf1 of the image forming unit PGU1 to the mirrors M21 and M22, such as lenses for optical adjustment.

[0044] Figure 15 shows a YZ view of Modification 1B as a modified example of Embodiment 1. In Figure 15, in the optical path from the display surface sf1 of the image forming unit PGU1, similar to that in Figure 3, to the mirrors M21 and M22, a first lens L1 is positioned on the optical path of the first image light C1 in the first region r1, and a second lens L2 is positioned on the optical path of the second image light C2 in the second region r2. Thus, lenses for optical adjustment may be provided on both the optical path of the first image light C1 and the optical path of the second image light C2.

[0045] In this modified example 1B, the direction of the two image beams C1 and C2 is first optically adjusted by the optical element 15, and further optical adjustment is performed by the subsequent lenses L1 and L2. Optical adjustment by lenses L1 and L2 includes adjustment of optical distance, etc. Also, in this modified example 1B, similar to Embodiment 1, the direction of the two image beams C1 and C2 is adjusted by the optical element 15 so that they spread toward the two mirrors M21 and M22, making it easier to position the two lenses L1 and L2.

[0046] In other variations, the optical distance and the like may be designed based on the optical path of one of the two image lights (e.g., image light C1) and the optical path of the other image light (e.g., image light C2), and a lens 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 Embodiment 1, as shown in Figure 3 and Figure 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 first image light C1 from the first region r1 forms a virtual image V1 of the first display region 51, and a second image light C2 from the second region r2 forms a virtual image V2 of the second display region 52. 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 path of the second image light C2 for the second display region 52 is separated from that of the first image light C1 by an optical element 15 located near the back side of the LCD 12, which bends the ray angle of the light source light from the light source device 11.

[0048] If the optical element 15 is composed of a lens instead of a prism, the lens is positioned at an eccentric position 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 two different folding mirrors, mirror M21 and mirror M22. Mirrors M21 and M22 are designed in terms of position and orientation to reflect the first image light C1 and the second image light C2 toward a single concave mirror M1.

[0050] In the HUD device 1 of Embodiment 1, the optical system is designed such that the optical path of the second image light C2 for forming the virtual image V2 of the second display area 52 is shorter in both optical path length and virtual image distance than the optical path of the first image light C1.

[0051] In Figure 3, as an example of the design of two display areas 5(51,52) based on a virtual image optical system, the first display area 51 is formed further back (towards the front of the vehicle) in the Y-axis direction than the second display area 52, and the first display area 51 is formed higher in the Z-axis direction than the second display area 52. The optical path and optical distance of the first image light C1 from the first area 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 area r2 of the image forming unit PGU2, due to the configuration in which it is folded back by the mirror M21. Therefore, the first display area 51 is formed further back (towards the front of the vehicle) in the Y-axis direction than the second display area 52. In addition, the position of the illumination of the first image light C1 to the mirror M1 is configured to be lower in the Z-axis direction than the illumination position of the second image light C2. Therefore, the first image light C1 projected from the mirror M1 to the windshield 3 is at a higher position than 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] As shown in Figure 3, the HUD device 1 of Embodiment 1 can form a layered display area 5 with 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 Embodiment 1 may optionally display virtual image V1 in only one of the first display areas 51, or virtual image V2 in only the other second display area 52, or it may display virtual images V1 and V2 simultaneously in both display areas 51 and 52.

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

[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, such an arrangement of virtual images 9 in two display areas 5 can be achieved.

[0055] [Regarding the design of polarization] In Figure 3, the following is an example of the design of the polarization characteristics of 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 Embodiment 1. The first image light C1 is light incident on the surface sf6 of the windshield 3 with S polarization (also referred to as first polarization). The second image light C2 is light incident on the surface sf6 of the windshield 3 with S polarization (first polarization). Note that in the drawings, S polarization may be indicated by (S) and P polarization by (P). S polarization (or S wave) is light in which the electric field vibrates in a direction perpendicular to the incident surface, and S represents senkrecht. P polarization (or P wave) is light in which the electric field vibrates within the incident surface, and P represents parallel. The first polarization and the second polarization are linearly polarized light that is orthogonal to each other.

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

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

[0058] [Image Forming Unit] Figure 4 shows a perspective view of an example configuration of the image forming unit PGU1, including the optical element 15 shown in Figure 3. In addition to the spatial coordinate system (X,Y,Z), Figure 4 also shows a coordinate system (x,y,z) based on the display surface sf1 of the LCD 12 of the image forming unit PGU1. The x-axis direction is the horizontal direction within the screen on the display surface sf1 (in other words, the horizontal direction), the y-axis direction is the vertical direction within the screen on the display surface sf1 (in other words, the vertical direction), and the z-axis direction is the direction perpendicular to the xy planes resulting from these axes.

[0059] In the 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, the space is divided into two regions for explanatory purposes, with the dashed line shown as the boundary, and these are referred to as the first region r1 and the second region r2. The first region r1 and the second region r2 on the xy-plane on the emission side of the light source device 11 are each shown as dashed rectangles, and the first region r1 and the second region r2 on the display surface sf1, which is the xy-plane on the emission side of the LCD 12, are each shown as dashed rectangles.

[0060] The optical element 15 is positioned in the second region r2, in the space connecting the xy plane on the emission side of the light source device 11 and the xy plane on the incident side of the LCD 12. In this example, the optical element 15 is composed of 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 aligned with 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 triangle shape, as shown in the figure. One side of this right triangle, which forms a right angle, is positioned close to the xy plane on the back side of the LCD 12, while the hypotenuse, which does not form a right angle, is positioned toward 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 from the first region r1 of the light source device 11 enters the back side of the LCD 12 without passing through the optical element 15, as indicated by the optical axis indicated by one dashed-dotted arrow. The LCD 12 uses the light from the first region r1 as a backlight and emits a first image light C1 based on the image displayed in the first region r1 on the display surface sf1. On the other hand, the light from the second region r2 of the light source device 11 enters the back side of the LCD 12 via the optical element 15, as indicated by the optical axis indicated by the other dashed-dotted arrow. The LCD 12 uses the light from the second region r2 as a backlight and emits a second image light C2 based on the image 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 aligned with 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 in optical paths that separate and spread out toward the two mirrors M21 and M22.

[0063] Furthermore, a diffuser or the like may be provided in the space prior to the position of the optical element 15, downstream of the light source device 11.

[0064] [HUD display area] Figure 5, corresponding to Figure 3, shows a schematic configuration in the XZ plane of the display area 5 (51, 52) formed by the video display unit 200 of the HUD device 1 of Embodiment 1, when the windshield 3 is viewed forward (Y-axis direction) from the driver's viewpoint 6. Figure 5 schematically shows the case in which two display areas 51 and 52 are formed by video light (the aforementioned video light C1, C2) reflected and projected onto the windshield 3 from the concave mirror M1. In particular, Figure 5 shows the case in which the two display areas 51 and 52 are formed partially overlapping in the vertical direction (Z-axis direction) when viewed from the viewpoint 6.

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

[0066] In the configuration example shown in Figure 5, within the effective area of ​​the reflective surface sf5 of the concave mirror M1, the area 401 reflected by the first image light C1 and the area 402 reflected by the second image light C2 partially overlap. As shown in Figure 3, there is an image inversion relationship through mirrors M1, M21, M22, etc., so the first image light C1 from the lower area 401 on the reflective surface sf5 of 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] Figure 6 shows a modified example of the formation of the display area 5, in particular, a case in which two display areas 51 and 52 are formed separately in the vertical direction (Z-axis direction) without overlapping, as viewed from viewpoint 6. In the effective area of ​​the reflective surface sf5 of the concave mirror M1, a portion of the lower side has an area 401 to which the first image light C1 is irradiated, and a portion of the upper side has an area 402 to which the second image light C2 is irradiated. The first display area 51 is formed by the first image light C1 from area 401, and the second display area 52 is formed by the second image light C2 from area 402. In the configuration example of Figure 6, in the effective area of ​​the reflective surface sf5 of the concave mirror M1, the area 401 to which the first image light C1 is reflected and the area 402 to which the second image light C2 is reflected are separated.

[0068] As shown in Figure 5, in the HUD device 1 of Embodiment 1, the components for reflecting the two image beams C1 and C2 from one image forming unit PGU1 are shared as a single concave mirror M1. The configuration of the illumination areas for the two image beams C1 and C2 within the effective region of the reflective surface sf5 of the concave mirror M1 is not limited to the configuration examples in Figures 5 and 6, and variations will be described later.

[0069] [Regarding measures against solar power] The HUD device 1 of Embodiment 1 also incorporates the following features for protection against sunlight. The functions and structures related to this protection against sunlight are composed of a combination of a polarizing element and an infrared (IR) cutter as described below.

[0070] First, an example of the polarizing element configuration is as follows. In Figure 3, the dust cover 71 provided at the opening of the 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] Furthermore, immediately behind the display surface sf1 of the LCD12 in the image forming unit PGU1, an optical element is provided: either a reflective polarizing element or an absorptive polarizing element. 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] Figure 16 shows a modified example 1C of the configuration of the polarizing element described above. In the example in Figure 16, an absorption-type polarizing element is placed as an optical element 16 immediately after the display surface sf1 of the LCD 12. This absorption-type polarizing element absorbs components other than S polarization for the first image light C1 and the second image light C2.

[0073] As a variation of the polarizing element described above, the display surface sf1 of the LCD12 may be divided into a first region r1 and a second region r2, and polarizing elements may be arranged in each region.

[0074] An example of a configuration related to IR cut is as follows. First, the dust cover 71 is provided with an IR absorption function. For example, an IR absorption sheet is provided as one layer on the dust cover 71.

[0075] Furthermore, mirrors M21 and M22 are composed of cold mirrors. Cold mirrors are mirrors that transmit infrared light and reflect visible light. The visible light reflected by the cold mirrors is the first image light C1 and the second image light C2.

[0076] In a configuration without sun protection, if external light such as sunlight enters the housing 60 through the dust cover 71 of the opening, the incident external light may be reflected by the concave mirror M1, and the reflected external light may enter the display surface sf1 of the image forming unit PGU1. In that case, the incident external light on the surface of the LCD 12, which is the display panel, can affect panel burn-in, which is undesirable. Therefore, Embodiment 1 has the above-described functions and structures for sun protection.

[0077] Figure 16 considers the case where ambient light, such as sunlight, enters the housing 60 through the dust cover 71 in the opposite direction to the image light C1 and C2. First, the IR component of the ambient light is cut by the IR absorption function of the dust cover 71. The ambient light is reflected by the concave mirror M1, and some of the reflected ambient light may be further reflected by mirrors M21 and M22. In this case, the cold mirrors, which are mirrors M21 and M22, cut the IR component of the incident ambient light. Some of the ambient light reflected by mirrors M21 and M22 may further go toward the image forming unit PGU1 and enter the display surface sf1. In this case, the reflective polarizing element or absorbing changing element, which is an optical element 16 located on the front side of the LCD 12, reflects or absorbs the ambient light. As a result, less ambient light reaches the display surface sf1 of the LCD 12. Therefore, panel burn-in of the LCD 12 can be prevented or reduced.

[0078] [About the light path blocking function and protection mode] Figure 7 is a schematic diagram illustrating the optical path blocking function (in other words, an external light incidence prevention function, etc.) and protection mode of the video display unit 200 in the HUD device 1 of Embodiment 1, shown in the YZ plane, similar to Figure 3. The HUD device 1 of Embodiment 1 is based on the configuration of the image forming unit PGU1 and mirrors M21, M22, and M1 in Figure 3, and further has an optical path blocking function related to countermeasures against sunlight. This optical path blocking function blocks the optical path of incident external light such as sunlight on the optical path from the dust cover 71 to the image forming unit PGU1, and in particular prevents external light from entering the display surface sf1 of the LCD 12. This function rotates the mirror M1 according to the control mode (sometimes described as a protection mode, etc.) to change the direction of the optical path of external light so that external light does not enter the display surface sf1 of the image forming unit PGU1, or in other words, changes the direction of the optical path of external light. This function prevents panel burn-in of the LCD 12, etc.

[0079] In Figure 7, the concave mirror M1 is provided with a rotation axis and a drive mechanism 61 such as a motor. The rotation axis of the drive mechanism 61 is an axis that extends 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 being driven by 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 Embodiment 1, the rotatable mechanism of the mirror M1 can be shared with the mechanism that adjusts the formation position of the display area 5 in the vertical direction 5a (Figure 5, etc.).

[0080] First, in the normal display mode, the HUD device 1 has the concave mirror M1 in state A, indicated by the dashed line. In state A, the optical axes of the image light C1 and C2 for the respective display areas 51 and 52 are as indicated by the dashed arrows. In the normal display mode, consider the external light incident path which is in the opposite direction to the optical axes of the image light C1 and C2. The external light a100, which is sunlight a100, indicated by the dashed arrow in the figure, shows the optical axis in this external light incident path. External light a101 shows the external light path in the opposite direction to the optical path of the first image light C1, and external light a102 shows the external light path in the opposite direction to the optical path of the second image light C2. When the external light a100 (a101, a102), which is sunlight in this external light incident path, passes through the dust 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 each image light C1 and C2. These external light rays are reflected by mirrors M21 and M22, directed towards the image forming unit PGU1, and incident on the display surface sf1. This affects the panel burn-in of the LCD12, so countermeasures are necessary.

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

[0082] As a result, in protection mode, the ambient light a101 and a102, which are sunlight a100 that enters the housing 60 through the dust cover 71, are reflected by the mirror M1 in state B and then proceed as ambient light a103 and a104, respectively. The direction of the optical path of ambient light a103, based on ambient light a101, is deviated so that it does not hit the surface sf21 (Figure 3) of the mirror M21. The direction of the optical path of ambient light a104, based on ambient light a102, is deviated so that it does not hit the surface sf22 (Figure 3) of the mirror M22.

[0083] More specifically, the optical path of the ambient light a103 is directed to a position offset downward in the Z-axis direction relative to the surface sf21 (Figure 3) of mirror M21. Since this ambient light a103 is not reflected by mirror M22, it does not enter the display surface sf1 of the image forming unit PGU1. Similarly, the optical path of the ambient light a104 is directed to a position offset downward in the Z-axis direction relative to the surface sf22 (Figure 3) of mirror M22. Although the optical path of this ambient light a104 strikes the surface sf21 (Figure 3) of mirror M21, which is behind and below mirror M22, the optical path of the ambient light a105, after this ambient light a104 is reflected by mirror M21, is directed to a position offset downward in the Z-axis direction relative to the display surface sf1 of the image forming unit PGU1. In other words, the direction of the optical path of ambient light a105, based on ambient light a102, is also offset so that it does not strike the display surface sf1 of the image forming unit PGU1.

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

[0085] A mechanism that alters the direction of the optical path of ambient light in accordance with the rotation of the mirror M1, in other words, a mechanism that blocks ambient light from entering the image forming unit PGU1, is possible in configurations other than those shown in Figure 7. Any configuration that changes the direction of the optical path so that the ambient light a103 and a104 reflected from the concave mirror M1 does not ultimately enter the display surface sf1 of the image forming unit PGU1, regardless of whether or not they are irradiated by mirrors M21 and M22, is sufficient.

[0086] Figure 17 shows Modification 1D of Embodiment 1, which relates to the optical path blocking function described above. In Modification 1D, the two mirrors M21 and M22 are spaced further apart in the Z-axis direction compared to the configuration example in Figure 7. Corresponding to the arrangement of these mirrors M21 and M22, the two image rays C1 and C2 from the display surface sf1 of the image forming unit PGU1 are designed using the optical element 15 to have a larger difference in their direction angles. In Modification 1D, in protection mode, when the concave mirror M1 is in state B, based on the incidence of ambient light a100 (a101, a102), the ambient light a103 and a104, which have been reflected by the concave mirror M1, are directed away from the direction of the optical path so that they do not hit the mirrors M21 and M22, respectively.

[0087] Specifically, the optical path direction of the ambient light a103, based on ambient light a101, is directed downwards relative to mirror M21. The optical path direction of the ambient light a104, based on ambient light a102, is directed downwards relative to mirror M22, particularly into the space between mirrors M22 and M21. Unlike in Figure 7, the optical path of ambient light a104 does not hit mirror M21. As a result, even in modified example 1D, ambient light can be prevented from entering the display surface sf1 of the image forming unit PGU1 in protection mode.

[0088] Furthermore, in Embodiment 1, the rotation direction of the mirror M1 is set to tilt from the rear to the front in the Y-axis direction as shown in Figure 7, thereby setting the direction of the optical axis of the ambient light reflected from the concave mirror M1 to be downward relative to each mirror M21 and M22, for example, ambient light a103 and ambient light a104. However, this is not the only possible configuration. In a modified example, the rotation direction of the mirror M1 may be set to tilt from the front to the rear, setting the direction of the optical axis of the ambient light reflected from the concave mirror M1 to be upward relative to each mirror M21 and M22. However, in that case, the reflective surface sf5 of the mirror M1 will face further upward, which may generate stray light inside the vehicle 2, and is therefore undesirable. For this reason, in Embodiment 1, the rotation direction of the mirror M1 is set to tilt forward as described above.

[0089] As described above, the HUD device 1 controls the drive so that the mirror M1 is in the first state (state A) in normal display mode and in the second state (state B) in protection mode. There are two possible ways to control switching to protection mode, for example. In the first case, the HUD device 1 is in protection mode when not in use or when the virtual image 9 is not displayed, and in normal display mode when the virtual image 9 is displayed. In addition, the HUD device 1 is in protection mode and blocks the ambient light path to protect the image forming unit PGU 1 even when the ignition switch of the vehicle 2 is in the OFF state.

[0090] In the second case, even in normal display mode, the HUD device 1 detects ambient light incidence based on sensors, as described later, and automatically switches to protection mode if it determines that ambient light incidence should be avoided from a temperature perspective. This control prioritizes avoiding ambient light incidence and preventing panel burn-in over displaying the virtual image 9.

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

[0092] Furthermore, in the implementation example shown in Figure 8, a solar radiation sensor 66 is provided near the dust cover 71. The solar radiation sensor 66 detects the incidence of ambient light, such as sunlight a100, within a detection range such as range 66a.

[0093] [Regarding the temperature detection unit and measures against sunlight] Figure 9 is a schematic diagram illustrating temperature control using the solar radiation sensor 66, etc., related to the optical path blocking function and protection mode of Figure 7. As will be described later (Figure 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 the detection information from the solar radiation sensor 66 in Figure 8. Figure 9 shows an example of the processing performed by the protection processing unit 1060. In Figure 9, mainly the image forming unit PGU1 is extracted and illustrated from Figures 3 and 7, etc., and the dust cover 71, solar radiation sensor 66, mirror M1, etc. are illustrated in a simplified manner.

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

[0095] First, the temperature (TP1) of the LCD 12 provided in the image forming unit PGU1 can be estimated by the ambient temperature Ta of the image forming unit PGU1, the temperature rise ΔT(I) due to ambient 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] In a simplified manner, it can be assumed that the ambient temperature Ta, temperature rise ΔT(I), temperature rise ΔT(L), etc. are approximately the same in the first region r1 and the second region r2 of the image forming unit PGU1, and the temperature TP1 of the LCD12 in each region can be estimated using a similar mechanism. More specifically, it may be assumed that the ambient temperature Ta, temperature rise ΔT(I), temperature rise ΔT(L), etc. are different in the first region r1 and the second region r2 of the image forming unit PGU1, and the temperature of the LCD12 in each region can be estimated accordingly.

[0097] The protection processing unit 1060 in Figure 11 of the HUD device 1 performs the following processing. 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 by a temperature sensor 912 (Figure 10) installed inside the vehicle 2. Based on the detection information from the temperature sensor, the protection processing unit 1060 determines the ambient temperature Ta of the image forming unit PGU1.

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

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

[0100] In the control example of Embodiment 1, the formula for calculating the temperature rise ΔT(I) on the LCD12 side is set individually according to the difference between the first region r1 and the second region r2. These respective formulas are shown as formulas G1 and G2. As a modification, in a simplified configuration, the formula for calculating the temperature rise ΔT(I) in the first region r1 and the second region r2 of the image forming unit PGU1 may be the same.

[0101] As described above, the protection processing unit 1060 indirectly detects the temperature TP1 of the display surface of the LCD 12 by performing calculations 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 thermal radiation from the 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 the light source device 11 and the temperature of the LCD 12, and it can be said that the temperature of the LCD 12 can be adjusted by adjusting the brightness or light intensity of the backlight of the light source device 11.

[0103] Therefore, the control unit 101 of the HUD device 1 controls the brightness or light intensity of the backlight of the light source device 11 according to 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 and adjusts the brightness or light intensity of the backlight of the light source device 11 if it exceeds the threshold. For example, if the detected temperature TP1 exceeds the set threshold Th1, the control unit 101 drives the backlight of the light source device 11 to decrease its brightness or light intensity, i.e., to decrease the duty cycle of the PWM control. This suppresses the temperature rise of the LCD 12 in the image forming unit GPU 1.

[0104] [Vehicle information and sensors] Figure 10 shows an example of the configuration of sensors, etc., for the vehicle information acquisition unit 1015 (Figure 11) of the HUD device 1, or the control unit 100 of the vehicle 2, to acquire the vehicle information 4 shown in Figure 1. Figure 10 shows examples of various sensors, in other words, information acquisition devices, measurement devices, communication devices, etc., connected to the vehicle information acquisition unit 1015 or the control unit 100. For example, the control unit 100 acquires vehicle information 4 from sensors, etc., 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. The control unit 100 also determines and detects various events related to the vehicle 2 based on the sensor detection information.

[0105] Vehicle Information 4 is a general term for information related to the driving status of Vehicle 2. Vehicle Information 4 includes ADAS information, etc. For example, Vehicle Information 4 includes information such as Vehicle 2's speed, gear information, steering angle information, lamp illumination information, ambient 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 vehicle-to-infrastructure communication information. Camera image information includes in-vehicle camera image information and exterior camera image information. GPS information includes current time information, latitude and longitude information.

[0106] Figure 10 shows various sensors, including a vehicle speed sensor 901, a shift position sensor 902, a steering angle sensor 903, a headlight sensor 904, an illuminance sensor 905, a chromaticity sensor 906, a distance sensor 907, an infrared sensor 908, an engine start sensor 909, an acceleration sensor 910, a gyro sensor 911, a temperature sensor 912, a vehicle-to-infrastructure wireless transceiver 913, a vehicle-to-vehicle wireless transceiver 914, an in-vehicle camera 915, an exterior camera 916, a GPS receiver 917, and a VICS (Vehicle Information and Communication System, registered trademark) receiver 918. These are not the only sensors that can be added, deleted, or replaced.

[0107] The vehicle speed sensor 901 detects the speed of 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 angle sensor 903 detects the current steering angle and generates steering 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 ambient light and generate ambient light information as the detection result.

[0108] The distance measuring sensor 907 detects the distance between the vehicle 2 and an external object and generates distance information as the detection result. The infrared sensor 908 detects the presence and distance of an object in close proximity to the vehicle 2 and generates infrared information as the detection result. The engine start sensor 909 detects the ON / OFF status of the engine and generates ON / OFF information as 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 representing 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 as the detection result.

[0109] The in-vehicle camera 915 generates in-vehicle camera video information by capturing images of the inside of vehicle 2. The exterior camera 916 generates exterior camera video information by capturing images of the outside of vehicle 2. In a specific example, camera 90 in Figure 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, and constitutes a Driver Monitoring System (DMS). By analyzing the in-vehicle camera video information, it is possible to understand the driver's fatigue level and gaze. The exterior camera 916 captures, for example, the surrounding situation in front of vehicle 2. By analyzing the exterior camera video information, it is possible to understand the presence or absence of other vehicles and people around vehicle 2, buildings and terrain, road surface conditions such as rain, snow, ice, and unevenness, and road signs. The exterior camera 916 also includes drive recorders that record driving conditions in video.

[0110] The vehicle-to-infrastructure wireless transceiver 913 generates vehicle-to-infrastructure communication information through vehicle-to-infrastructure communication between the vehicle 2 and roads, signs, traffic lights, etc. The vehicle-to-vehicle wireless transceiver 914 generates vehicle-to-vehicle communication information through vehicle-to-vehicle communication between the vehicle 2 and other surrounding vehicles. The GPS receiver 917 generates GPS information by receiving GPS signals from GPS satellites. For example, the current time, latitude, and longitude can be obtained 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] Figure 11 shows an example of the configuration of the functional blocks of the HUD device 1. In the configuration example of Figure 11, corresponding to the configuration of the image forming unit PGU1 and concave mirror M1 as shown in Figure 3, it has a display driver 1021 and a light source drive unit 1022, etc. In this configuration example, a video processing unit 1013 is provided that is connected to the display driver 1021 and the light source drive unit 1022.

[0112] In Figure 11, the HUD device 1 includes a control unit 101, a video display unit 200, a mirror drive unit 1020, a display driver 1021, a light source drive unit 1022, an audio driver 1025, an audio output device 1041, an audio input device 1042, etc. The control unit 101 includes an MCU (microcontroller unit) 1010, a non-volatile memory 1011, a volatile memory 1012, a video 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. Each of these units is interconnected via a bus or the like, and can perform input / output and communication with each other.

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

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

[0115] The communication unit 103 is a device equipped with a communication interface. The communication unit 103 is connected to the control unit 100 (e.g., an electronic control unit: ECU) via an interface such as the vehicle 2's CAN (Controller Area Network) or LIN (Local Interconnect Network) and can communicate with it.

[0116] The mirror drive unit 1020 is a device that drives the drive mechanism 61 of the concave mirror M1 based on control from the control unit 101.

[0117] The display driver 1021 is a device that includes a drive circuit and the like for driving the LCD 12 of the image forming unit PGU1 based on control from the control unit 101.

[0118] The light source drive unit 1022 is a device that includes a drive 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 drive unit 1022 has a drive circuit and the like that which can change the on / off state and light intensity of each light source element of the light source device 11.

[0119] The audio input device 1042 consists of a microphone and circuitry, etc. The audio output device 1041 consists of a speaker and circuitry, etc. Although the diagram shows the HUD device 1 equipped with the audio input device 1042 and the audio output device 1041, the HUD device 1 is not limited to this configuration and may utilize an external audio input device 1042 and an audio output device 1041 connected to the vehicle 2 (for example, the control unit 100).

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

[0121] Furthermore, the control unit 101 may acquire user input information through the operation input unit 1017. The operation input unit 1017 may be a remote control or the like. Also, when the HUD device 1 outputs audio, the control unit 101 generates audio output information and controls the audio driver 1025. Furthermore, when the control unit 101 receives voice input from a user such as a driver, it performs voice recognition based on the input audio from the audio input device 1042 and accepts predetermined instructions, etc.

[0122] The configuration example in Figure 11 is not limited to the HUD device 1, and the HUD device 1 may be equipped with various sensors, including, for example, a solar radiation sensor 66 (Figure 8). The control unit 101 may use the detection information from these sensors to determine and detect the state of the HUD device 1 and the state of the vicinity of the HUD device 1, and perform predetermined control.

[0123] The components of the control unit 101 and other parts shown in Figure 11 may be mounted inside the housing 60 of the video display unit 200 shown in Figure 3, etc., or they may be connected to the outside of the housing 60.

[0124] [Example of video display control] An example of video display control by the control unit 101 in Figure 11 is as follows. Based on input information such as vehicle information 4 and input video data, the control unit 101 generates video data for displaying a virtual image 9 in the display area 5. For example, the HUD device 1 decides to display a first virtual image V1 in the first display area 51, such as an AR navigation image or an alert image, and simultaneously display a second virtual image V2 in the second display area 52, such as distance information or vehicle speed information, which are not AR. To this end, the control unit 101 generates first video data with the first area r1 of the LCD 12 of the image forming unit PGU 1 as the output destination, and second video data with the second area r2 as the output destination.

[0125] The control unit 101 performs distortion correction considering the difference in curvature of the windshield 3, and also adjusts the on / off state and light intensity of the light source based on the video data of the display source. Based on the video data, the control unit 101 drives the display driver 1021 and the light source drive unit 1022. The display driver 1021 drives the LCD 12 based on the signal from the control unit 101. The light source drive unit 1022 drives the light source device 11 based on the 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 a first image light C1 based on the light from the light source device 11 and the image formed in the first region r1 of the LCD 12, and emits a second image light C2 based on the light from the light source device 11 and the image formed in the second region r2 of the LCD 12.

[0126] Furthermore, as described above, the protection processing unit 106 of the control unit 101 in Figure 11 performs processing corresponding to the control of switching between the normal display mode and the protection mode based on the detection information from the solar radiation sensor 66.

[0127] [Example of image forming unit configuration] The following are examples of implementation configurations for the image forming unit GPU1, which is the video display device 10. Figure 12 shows an example of an implementation configuration for the image forming unit PGU1. The image forming unit PGU1 in Figure 12 comprises a light source device 11 and an LCD 12. The light source device 11 is composed of an LED substrate 201, LED elements 202, a reflector 203, a heat sink 204, a polarization conversion element 205, a light guide 206, a diffuser plate 206, etc. The light source device 11 is configured as a light source module by fixing these components to a case.

[0128] Multiple LED elements 202 are arranged on the LED substrate 201. Figure 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 in a way that changes its direction, converting it into nearly parallel light. The heat sink 204 dissipates heat and cools the LED substrate 201.

[0129] The polarization conversion element 205 receives approximately parallel light from the reflector 203, performs polarization conversion to match the polarization characteristics, and emits the approximately parallel light after polarization conversion to the light guide 206. The polarization conversion element 205 is composed of, for example, a combination of a polarization conversion prism and a waveplate. In Embodiment 1, the polarization conversion in the polarization conversion element 205 in the image forming unit PGU1 is a polarization conversion to match the polarization perpendicular to the absorption axis of the incident polarizer of the LCD 12.

[0130] The light guide 206 receives approximately parallel light from the polarization conversion element 205 in a first direction, directs it to the reflective surface, and reflects it in a second direction. The second direction is towards the LCD 12. As shown in the partially enlarged view, the reflective surface of the light guide 206 has a plurality of reflective surfaces 206a and a plurality of connecting surfaces 206b, with each reflective surface 206a and connecting surface 206b arranged alternately. The reflective surface of the light guide 206 also achieves a predetermined light distribution control. Each of the plurality of reflective surfaces 206a has its own inclination to achieve a reflection direction corresponding to the predetermined light distribution control.

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

[0132] [Effects of Embodiment 1, etc.] As described above, the HUD device 1 of Embodiment 1 can suitably form two display areas 5 (51, 52) on which virtual images 9 can be displayed, particularly layered display areas. As a result, the HUD device 1 can 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 Embodiment 2 will be described using Figures 13 and later. Below, the components of Embodiment 2 that differ from those of Embodiment 1 will be mainly described. In Embodiment 2, the lower of the two mirrors M21 and M22 in the Z-axis direction, M21, is composed of a concave mirror 1301. The first image light C1 reflected by this concave mirror 1301 is first imaged at a predetermined point P1 before being incident on the concave mirror M1. Point P1, the image formation position of mirror M21, is located near mirror M22. In a specific example, point P1 is located at a predetermined position below mirror M22 in the Z-axis direction. By using an optical system that forms an image with the concave mirror 1301 in this way, the image forming unit PGU1 and mirror M21 can be positioned closer to the concave mirror M1 and mirror M22. With this configuration, the HUD device 1 of Embodiment 2 can be made smaller, and the image display unit 200 can be made smaller.

[0134] In Embodiment 2, as described above, the optical system is such that an image is formed by the concave mirror 1301 in the optical path of the first image light C1. Therefore, the relationship between 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, is inverted vertically. The first image light C1 from the first region r1 is reflected by the concave mirror 1301, resulting in an inverted image light C1 that enters the concave mirror M1. The second image light C2 from the second region r2, which passes through the optical element 15, is reflected by the planar mirror M22, similar to Embodiment 1, and enters the concave mirror M1. The respective image lights C1 and C2 reflected from the concave mirror M1 form virtual images 9(V1,V2) of two display regions 5(51,52) on the windshield 3, similar to Embodiment 1. The virtual image V1 in the first display area 51 and the virtual image V2 in the second display area 52 appear as vertically aligned images from the driver's viewpoint 6.

[0135] [Regarding measures against solar power] The configuration for countermeasures against sunlight in the HUD device 1 of Embodiment 2 is as follows. This configuration is the same as the configuration for countermeasures against sunlight in Embodiment 1 described above, and consists of a combination of a polarizing element and an IR cut as shown below.

[0136] First, an example of the polarizing element configuration is as follows. In Figure 13, the dust cover 71 provided at the opening of the video 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 video light (first video light C1 and second video light C2).

[0137] Furthermore, immediately behind the display surface sf1 of the LCD12 in the image forming unit PGU1, an optical element is provided: either a reflective polarizing element or an absorptive polarizing element. 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] Figure 13 also shows an example configuration of the polarizing element described above. In this example, an absorption-type polarizing element is placed as an optical element 16 immediately after the display surface sf1 of the LCD 12. This absorption-type polarizing element absorbs components other than S polarization for the first image light C1 and the second image light C2.

[0139] As a variation of the polarizing element described above, the display surface sf1 of the LCD12 may be divided into a first region r1 and a second region r2, and polarizing elements may be arranged in each region.

[0140] An example of the configuration related to IR cut is as follows. First, the dust cover 71 is provided with an IR absorption function. For example, an IR absorption sheet is provided as one layer on the dust cover 71. Also, the concave mirrors 1301, mirrors M21 and M22, are made of cold mirrors.

[0141] Figure 13 considers the case where ambient light, such as sunlight, enters the housing 60 through the dust cover 71 in the opposite direction to the image light C1 and C2. First, the IR component of the ambient light is cut by the IR absorption function of the dust cover 71. The ambient light is reflected by the concave mirror M1, and some of the reflected ambient light may be further reflected by mirrors M21 and M22. In this case, the cold mirrors M21 and M22 cut the IR component of the incident ambient light. Some of the ambient light reflected by mirrors M21 and M22 may further go toward the image forming unit PGU1 and enter the display surface sf1. In this case, the optical element 16 on the front side of the LCD 12 reflects or absorbs that ambient light. As a result, less ambient light reaches the display surface sf1 of the LCD 12. Therefore, panel burn-in of the LCD 12 can be prevented or reduced.

[0142] As a modification of Embodiment 2, the first image light C1 and the second image light C2 from the image forming unit PGU1 may be configured in which the characteristics of S-polarization and P-polarization are reversed.

[0143] [Effects of Embodiment 2, etc.] As described above, the HUD device 1 of Embodiment 2 offers advantages such as being able to suitably form two display areas 5 (51, 52) similar to Embodiment 1, as well as enabling a further miniaturization of the video display unit 200.

[0144] [Regarding the relationship between the effective area and display area of ​​a concave mirror] In Embodiment 1 and others, various configurations are possible regarding the relationship between the effective area illuminated by the two image lights C1 and C2 on the reflective surface sf5 of the concave mirror M1 and the formation positions of the two display areas 5 (51, 52), so further explanation is provided below. Two configuration examples are shown in Figures 5 and 6 above, but the invention is not limited to these. Modified examples are shown in Figures 18 and 19. Figure 18 is the third configuration example, and Figure 19 is the fourth configuration example.

[0145] In the third configuration example shown in Figure 18, the two effective areas formed by the two image lights C1 and C2 are separated and formed as regions 401 and 402 in the concave mirror M1. In contrast, depending on the design details of the optical system, the two display regions 5 (51, 52) are formed to overlap when viewed from viewpoint 6. Details of the optical system design include the design of the position and orientation of the image forming unit, and the design of the shape of each mirror M21, M22, M1 and the direction of reflection of each image light.

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

[0147] Although the present invention has been specifically described above based on embodiments, the present invention is not limited to the embodiments described above 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. Combinations of each embodiment are also possible.

[0148] As described above, using the technology according to the embodiment, the effective area of ​​the display panel corresponding to the video light from the light source device is divided into a first region and a second region. A virtual image is formed in the first display region by the first video light from the first region, and a virtual image is formed in the second display region by the second video light from the second region. By providing a technology that can form two virtual images corresponding to two display regions in front of the windshield from the driver's perspective, it is possible to provide the driver with various virtual images for driving assistance and other purposes, thereby providing an information display device (head-up display device) that contributes to safe driving. This makes it possible to prevent traffic accidents. Furthermore, it becomes possible to contribute to "3. Good Health and Well-being" of the United Nations' Sustainable Development Goals (SDGs). [Explanation of symbols]

[0149] 1...HUD device, 2...Vehicle, 3...Windshield, 4...Vehicle information, 5, 51, 52...Display area, 6...Viewpoint, 7...Opening, 8...Handle, 9, V1, V2...Virtual image, 10...Image display device, 15...Optical element, 60...Housing, 71...Dust cover, 200...Image display unit, PGU1...Image forming unit, M1, M21, M22...Mirrors, C1, C2...Image light, r1...First region, r2...Second region.

Claims

1. An image forming unit that draws an image on a display panel and emits video light, An optical element provided in the image forming unit for generating image light that is divided into two parts, a first image light and a second image light, A first virtual image optical system that projects the first image light to display a first virtual image, A second virtual image optical system that projects the second image light to display a second virtual image, Equipped with, A first image is drawn in the first region from which the first video light of the display panel is emitted. A second image is drawn in the second region from which the second video light of the display panel is emitted. The orientations of the images in the first and second images are inverted vertically relative to each other. The orientation of the first virtual image and the second virtual image displayed by the first virtual image optical system and the second virtual image optical system is the same. Head-up display device.

2. In the head-up display device according to claim 1, The first virtual image optical system includes a first folding mirror, The second virtual image optical system includes a second folding mirror, The shapes of the first folding mirror and the second folding mirror are different. Head-up display device.

3. In the head-up display device according to claim 2, The first folding mirror is composed of a concave mirror, The second folding mirror is composed of a flat mirror. Head-up display device.

4. In the head-up display device according to claim 2, The first image light reflected by the first folding mirror and the second image light reflected by the second folding mirror are reflected by a common projection unit to form the first virtual image and the second virtual image. Head-up display device.

5. In the head-up display device according to claim 4, The light rays constituting the first image light intersect between the first folding mirror and the projection unit. Head-up display device.

6. In the head-up display device according to claim 1, The first virtual image and the second virtual image are formed to be separated or superimposed in the vertical direction, in front of the transparent member as viewed from the viewpoint of the vehicle driver. Head-up display device.

7. In the head-up display device according to claim 1, The first virtual image and the second virtual image are formed such that, from the perspective of the vehicle driver, the first virtual image is positioned in front of the transparent member, and the first virtual image is positioned relatively farther away from the second virtual image in the front-rear direction. Head-up display device.

8. In the head-up display device according to claim 4, The projection unit is composed of a mirror, and on the reflective surface, the region to which the first image light is irradiated and the region to which the second image light is irradiated are separated or superimposed. Head-up display device.

9. In the head-up display device according to claim 4, The projection unit is composed of mirrors and has a drive mechanism that rotates around a rotation axis that extends laterally. In the protection mode relative to the normal display mode, the mirror is rotated, and when ambient light is incident on the mirror in the opposite direction to the direction of the image light, the direction of the ambient light from the mirror to the first folding mirror and the second folding mirror is changed so that the ambient light reflected by the mirror does not incident on the display surface of the image forming unit. Head-up display device.

10. In the head-up display device according to claim 9, Equipped with a solar radiation sensor or a temperature sensor, Based on the detection information from the solar radiation sensor or the temperature sensor, when the incidence of ambient light is detected, the system switches from the normal display mode to the protection mode. Head-up display device.

11. In the head-up display device according to claim 1, A reflective polarizing element or an absorbing polarizing element is arranged on the front side of the display panel. Head-up display device.

12. In the head-up display device according to claim 1, The opening is provided with a dustproof cover that transmits the first and second video light and absorbs IR. Head-up display device.

13. In the head-up display device according to claim 1, The system includes a control unit that controls the image to be drawn on the display panel, The orientation of the images of the first image and the second image is set by the control unit. Head-up display device.

Images