Head-up display device

Abstract

Provided is a technique for a head-up display device (HUD device), whereby a plurality of display regions in which virtual images can be displayed can be appropriately formed. According to the invention, a contribution is made to the sustainable development goal of "3 to everyone's health and welfare". The HUD device includes: an image forming unit PGU1; an optical element (15) that is provided in the image forming unit (PGU1) and that generates image light divided into two pieces of first image light and second image light; a first mirror (M21) that reflects the first image light; a second mirror (M22) that reflects the second image light; and a mirror (M1) that reflects the first image light from the first mirror and the second image light from the second mirror, forms a first display area in which a first virtual image can be displayed on the basis of the first image light from the mirror (M1), and forms a second display area in which a second virtual image can be displayed on the basis of the second image light from the mirror (M1).

Description

Technical Field

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

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

[0003] As an example of the prior art, Japanese Patent Publication No. 2016-14861 (Patent Document 1) is cited. In Patent Document 1, it is recorded that "a head-up display device capable of efficiently directing image light toward an observer through a simple structure is provided", "a projection unit 10 emits projection light 200a representing a display image, a first reflection unit 21 reflects the projection light 200a emitted by the projection unit 10 toward a second reflection unit 24, the second reflection unit 24 reflects the projection light 200a reflected by the first reflection unit 21 toward a transmission-type screen 30, and the transmission-type screen 30 emits image light 100 toward an observer obtained by transmitting and diffusing the projection light 200a reflected by the second reflection unit 24. The angle of the optical axis of the projection light 200a incident on the transmission-type screen 30 is adjusted by rotating the first reflection unit 21 and the second reflection unit 24, thereby adjusting the angle of the image light 100 emitted from the transmission-type screen 30".

[0004] Prior art literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-14861 Summary of the invention

[0006] A HUD device of a conventional example such as Patent Document 1 can provide a virtual image according to the height position of the viewpoint of a driver (observer) by rotating a mirror to change the direction of image light.

[0007] The present disclosure aims to provide a technology capable of appropriately forming a plurality of display areas capable of displaying virtual images, in relation to the technology of the HUD device. In other words, the display area refers to a display area, a display region, a screen, etc. of the HUD.

[0008] A representative embodiment of the present disclosure has the following structure. The head-up display device of the embodiment includes: an image forming unit that emits image light; an optical element provided in the image forming unit for generating image light divided into two, namely, a first image light and a second image light, as image light; a first folding mirror that reflects the first image light; a second folding mirror that reflects the second image light; and an image projection unit that reflects the first image light from the first folding mirror and the second image light from the second folding mirror, and forms a first display area as a first display area capable of displaying a first virtual image based on the first image light from the image projection unit, and forms a second display area as a second display area capable of displaying a second virtual image based on the second image light from the image projection unit.

[0009] According to the representative embodiment of the present disclosure, the technology of the HUD device can appropriately form a plurality of display areas capable of displaying a virtual image. Other issues, structures, effects, etc. than those described above are shown in the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A configuration example of a vehicle equipped with the HUD device according to the first embodiment is shown.

[0011] Figure 2 Show Figure 1 A structural example of installing a HUD device in a vehicle.

[0012] Figure 3 A configuration example of a video display unit and the like in the HUD device according to the first embodiment is shown.

[0013] Figure 4 A configuration example of an image forming unit in the HUD device according to the first embodiment is shown.

[0014] Figure 5 A first configuration example of two display areas viewed from the driver's viewpoint in the HUD device according to the first embodiment is shown.

[0015] Figure 6 A second configuration example of two display areas viewed from the driver's viewpoint in the HUD device according to the first embodiment is shown.

[0016] Figure 7 A schematic explanatory diagram related to the optical path blocking function and the like in the HUD device according to the first embodiment is shown.

[0017] Figure 8 An example of a mounting structure of a mirror, a dust cover, etc. of an image display unit in the HUD device according to the first embodiment is shown.

[0018] Fig. 9A schematic explanatory diagram related to temperature detection associated with the optical path blocking function in the HUD device according to the first embodiment is shown.

[0019] Fig.10 A configuration example of a sensor and the like for acquiring vehicle information in the HUD device according to the first embodiment is shown.

[0020] Fig.11 A configuration example of functional blocks in the HUD device according to the first embodiment is shown.

[0021] Fig.12 An example of a mounting structure of an image forming unit in the HUD device according to the first embodiment is shown.

[0022] Fig.13 A configuration example of a video display unit and the like in a HUD device according to a second embodiment is shown.

[0023] Fig.14 A configuration example of a video display unit and the like in a HUD device according to a modification 1A of the first embodiment is shown.

[0024] Fig.15 A configuration example of a video display unit and the like in a HUD device according to a modification 1B of the first embodiment is shown.

[0025] Fig.16 A configuration example of a video display unit and the like in a HUD device according to a modification 1C of the first embodiment is shown.

[0026] Fig.17 A schematic explanatory diagram showing an optical path blocking function and the like in a HUD device according to a modification 1D of the first embodiment.

[0027] Fig.18 A third configuration example of two display areas viewed from the driver's viewpoint in the HUD device according to the first embodiment is shown.

[0028] Fig.19 A fourth configuration example of two display areas viewed from the driver's viewpoint in the HUD device according to the first embodiment is shown. DETAILED DESCRIPTION

[0029] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the accompanying drawings, the same symbols are attached to the same parts in principle, and repeated descriptions are omitted. In the accompanying drawings, the actual position, size, shape, range, etc. of the components are sometimes not shown in order to facilitate the understanding of the invention.

[0030] In terms of description, when describing program-based processing, sometimes the program, function, processing unit, etc. are used as the main body for description, but the main body of their hardware is a processor, or a controller, device, computer, system, etc. composed of the processor, etc. The computer uses resources such as memory and communication interface appropriately through the processor, and executes processing according to the program read out to the memory. Thus, predetermined functions, processing units, etc. are realized. The processor is composed of semiconductor devices such as CPU / MPU and GPU, etc. The processing is not limited to software program processing, and it can also be installed through a dedicated circuit. The dedicated circuit can apply FPGA, ASIC, CPLD, etc.

[0031] The program can be installed in advance as data on the target computer, or it can be distributed as data from the program source to the target computer. The program source can be a program distribution server on a communication network, or it can be a non-temporary computer-readable storage medium, such as a memory card or a disk. The program can also be composed of multiple modules. The computer system can also be composed of multiple devices. The computer system can also be composed of a client-server system, a cloud computing system, an IoT system, etc. Various data and information are composed of structures such as tables and lists, but are not limited to this. The expressions of identification information, identifiers, IDs, names, numbers, etc. can be interchangeable.

[0032] <Solutions, etc.>

[0033] 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 when observed from the driver's viewpoint. In order to realize such a structure, the HUD device of the embodiment studies the structure of the optical system such as the image forming unit or the image forming part, the mirror, etc. Specifically, Figure 3 As shown in FIG. 1 and FIG. 2 , an image forming unit PGU1 as an image display device, two folding mirrors, namely, mirrors M21 and M22 , and a concave mirror M1 are provided in the image display unit 200 of the HUD device 1 .

[0034] The image forming unit PGU1 includes a light source and a display panel, and between the light source and the display panel, an optical element 15 is arranged in the second region r2 of the first region r1 and the second region r2 as a predetermined region divided into two on the display surface, and the optical element 15 is not arranged in the first region r1. Thus, the image forming unit PGU1 emits the first image light C1 from the corresponding first region r1 of the display panel based on the light passing through the first region r1, and emits the second image 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.

[0035] The HUD device of the embodiment uses two mirrors M21 and M22 as folding mirrors to respectively reflect two image lights C1 and C2 from the image forming unit PGU1 . The mirror M21 reflects the image light C1 , and the mirror M22 reflects the image light C2 .

[0036] Furthermore, the image projection unit M1 reflects the two image lights C1 and C2 from the two mirrors M21 and M22 toward the windshield 3. The image projection unit M1 of the present invention is a concave mirror. Thus, two HUD display areas 5 (51, 52) corresponding to the two image lights C1 and C2 from the image forming unit PGU1 are formed. When observed from the driver's viewpoint 6, in front of the windshield 3, 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.

[0037] For example, when viewed from the driver's viewpoint 6, the first virtual image V1 of the first display area 51 is formed at a relatively far and upper position relative to the second virtual image V2 of the second display area 52, and the second virtual image V2 of the second display area 52 is formed at a relatively near and lower position relative to the first virtual image V1 of the first display area 51. In order to design such a virtual image optical system and virtual image distance, the HUD device of the embodiment is designed so that the optical path of the first image light C1 is optically longer than the optical path of the second image light C2 in the frame.

[0038] Specifically, the image display unit 200 reflects and returns the first image light C1 generated by the first region r1 of the image forming unit PGU1 by using the mirror M21 disposed at the farther side, and reflects and returns the second image light C2 generated by the optical element 15 of the second region r2 of the image forming unit PGU1 by using the mirror M21 disposed at the closer side. Furthermore, in order to make the two image lights C1 and C2 incident separately toward the two mirrors M21 and M22, the image forming unit PGU1 uses the optical element 15 of the second region r2 to make the emission direction of the second image light C2 different from the emission direction of the first image light C1.

[0039] In addition, the optical element 15 of the second region r2 in the image forming unit PGU1 is used to perform optical adjustments including the optical distance and projection direction of the two image lights C1 and C2. The HUD device of the embodiment has a structure such that the optical path of the first image light C1 is optically longer than the optical path of the second image light C2 by the structure as described above.

[0040] <Implementation Method 1>

[0041] use Figures 1 to 12The HUD device 1 according to the first embodiment will be described below. The HUD device 1 according to the first embodiment is a HUD device mounted on a vehicle, and is an AR-HUD capable of displaying a virtual image based on AR.

[0042] [vehicle]

[0043] Figure 1 The schematic structure of a vehicle 2 equipped with the HUD device 1 of the first embodiment is shown. The vehicle 2 includes a control unit 100 as a vehicle controller. The control unit 100 controls the driving of the vehicle 2, etc. The HUD device 1 communicates with the control unit 100 via an interface such as CAN or LIN. The control unit 100 and the HUD device 1 constitute an on-board system of the vehicle 2. The HUD device 1 generates image light and projects it onto the transmission area of ​​the windshield 3. As a result, a display area 5 is formed as a display area for the transmission area of ​​the windshield 3, and a virtual image is displayed in the display area 5.

[0044] The control unit 100 controls the HUD device 1 via a CAN signal or the like, thereby enabling the video information to be displayed as a virtual image on the display area 5. The control unit 100 uses the following Fig.10 Such various sensors, measuring devices, communication devices, etc. acquire vehicle information 4. The HUD device 1 inputs / acquires the vehicle information 4 and the like from the control unit 100 via a CAN signal and the like. The HUD device 1 generates image data based on the vehicle information 4 and the like and emits image light, thereby displaying a virtual image in the display area 5.

[0045] In addition, Figure 1 In the examples, (X, Y, Z) are used as coordinate systems and directions for explanation. Figure 1 , etc., show the spatial coordinate system for the vehicle 2. The Z axis and the Z direction are the vertical direction, in other words, the up-down direction, the longitudinal direction. The X axis and the X direction are the first horizontal direction, in other words, the left-right direction, the lateral direction. The Y axis and the Y direction are the second horizontal direction orthogonal to the X axis, in other words, the front-back direction.

[0046] [Image display unit]

[0047] Figure 2 Show Figure 1 An example of mounting the HUD device 1 according to the first embodiment in a vehicle 2. Figure 2 In the figure, the X-axis direction is shown. Figure 1 A schematic diagram of the vehicle 2 in the YZ plane. Figure 2 In the embodiment, the HUD device 1, in particular, the image display unit 200 is mounted in the instrument panel 70 of the vehicle 2. Figure 22 shows a situation where the driver U1, as the user U1, is sitting in the driver's seat in the vehicle 2 and visually recognizes a virtual image 9 in the display area 5 in front of the vehicle 2 through the windshield 3. The image display unit 200 of the HUD device 1 includes an image display device 10, a mirror M2, and a concave mirror M1. In the frame, an optical system such as the image display device 10, the mirror M2, and the concave mirror M1 is arranged / fixed in a predetermined positional relationship.

[0048] In addition, Figure 2 The basic structure is shown in the figure, and the following Figure 3 Such a mirror and two display areas are collectively illustrated as an image display device 10 as one image forming unit and one display area 5, and the details will be described later.

[0049] A portion of the frame has an opening configured to match the opening 7 of the instrument panel 70. A dust cover 71 ( Figure 3 The image light of the HUD device 1 is emitted through the dust cover 71 and the like of the opening.

[0050] The image display device 10 forms an image on the display surface and emits image light. The mirror M2 is, for example, a folding mirror composed of a plane mirror. The mirror M2 reflects the image light from the image display device 10 toward the concave mirror M1. The mirror M1 is a concave mirror, and functions as an image projection unit that amplifies and reflects the image light from the mirror M2 in the direction of a set angle. The concave mirror M1 is, for example, composed of a free-form mirror, a mirror with an asymmetric shape of the optical axis, etc. The concave mirror M1 is composed of a mirror having a concave reflective surface on the X-axis and the Z-axis.

[0051] As shown in the figure, the image light from the image display device 10 is reflected by the mirror M2 and the concave mirror M1, and the reflected image light is emitted from the opening 7 and projected onto the surface of the windshield 3. The image light is reflected by the surface of the windshield 3 and is directed toward the driver's viewpoint 6. Thus, when observing the front (the rear side of the Y axis) from the driver's viewpoint 6, a display area 5 of the HUD is formed for the windshield 3, and a virtual image 9 can be visually recognized in the display area 5. In the display area 5, a virtual image 9 formed by the image light is displayed in a state superimposed on the real scene in front. In addition, in Figure 2 , as the display area 5 , 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 are shown, and they correspond to each other.

[0052] The virtual image 9 is image information that is displayed overlappingly in accordance with the position of the object in the case of AR (Augmented Reality). The virtual image 9 is image information that is displayed independently at a predetermined position in the case of non-AR. Examples of image information that becomes the virtual image 9 include various examples such as vehicle speed information, navigation information, and warning information.

[0053] The vehicle 2 is further provided with a camera 90, for example, near a rearview mirror. The camera 90 includes an exterior camera for capturing images of the exterior of the vehicle and an interior camera for capturing images of the interior of the vehicle.

[0054] [HUD device]

[0055] Figure 3 1 is a schematic explanatory diagram showing the structure of the image display unit 200 and the structure of the display area 5 on the YZ plane as the structure of the HUD device 1 according to the first embodiment. Figure 3 As one of the features in the first embodiment, the HUD device 1 includes: an image forming unit PGU1 including an optical element 15; two return mirrors, namely, mirrors M21 and M22; and a concave mirror M1. In addition, the HUD device 1 generates two image lights C1 and C2 using the optical element 15 through the image forming unit PGU1 and emits them separately in respective directions, and reflects the two image lights C1 and C2 using the two mirrors M21 and M22, and also using the common concave mirror M1. Thus, two display areas 5 (51, 52) are formed.

[0056] The image display unit 200 is provided with an image generation unit PGU1 as an image generation unit (Picture Generation Unit) in the frame 60. In other words, the image generation unit PGU1 is an image display device 10. The image generation unit PGU1 has: a light source device 11; and a liquid crystal display panel (LCD) 12 arranged at the rear stage of the light source device 11, in other words, arranged at the emission side, and the liquid crystal display panel (LCD) 12 is an example of a display panel as a display device. An optical element 15 is arranged in the second region r2 between the light source device 11 and the LCD 12, and the optical element 15 is not arranged in the first region r1.

[0057] Figure 3 The mirror M1 and mirrors M21, M22 and Figure 2The mirrors M1 and M2 in the embodiment correspond to each other. In the Y-axis direction, mirrors M21 and M22 are arranged at the front side (rear side of the vehicle or driver's side), and mirror M1 is arranged at the rear side (front side of the vehicle). Mirror M21 is the first folding mirror, and mirror M22 is the second folding mirror. In embodiment 1, the two mirrors M21 and M22 are plane mirrors. Mirror M21 has a reflecting surface sf21, and mirror M22 has a reflecting surface sf22. Mirror M1 is a concave mirror, and has a concave reflecting surface sf5.

[0058] exist Figure 3 In the embodiment, the image forming unit PGU1 emits the first image light C1 from the first region r1 and emits the second image light C2 from the second region r2. As a configuration for reflecting the first image light C1 and the second image light C2 by the mirrors M21 and M22, the image forming unit PGU1 is configured at a predetermined position that is on the front side of the vehicle in the Y-axis direction and on the lower side in the Z-axis direction relative to the mirrors M21 and M22.

[0059] Regarding the first image light C1 and the second image light C2 emitted from the display surface sf1 of the image forming unit PGU1, the projection direction and the like are optically adjusted by the action of the optical element 15. The first image light C1 is incident on the surface sf21 of the mirror M21 and is reflected, and the second image light C2 is incident on the surface sf22 of the mirror M22 and is reflected.

[0060] The first image light C1 reflected from the mirror M21 and the second image light C2 reflected from the mirror M22 are directed toward the mirror M1. The mirror M1 reflects the first image light C1 and the second image light C2 in a reflecting surface sf5. As described later, the irradiated areas of the first image light C1 and the second image light C2 in the reflecting surface sf5 may also be different. The first image light C1 and the second image light C2 reflected in the reflecting surface sf5 of the mirror M1 are respectively transmitted through the dust cover 71 arranged corresponding to the opening, and are projected onto the surface sf6 of the windshield 3.

[0061] The image light C1 and the image light C2 are reflected by the surface sf6 of the windshield 3 and are directed toward the driver's viewpoint 6. When the front is viewed from the viewpoint 6, the first image light C1 of the image forming unit PGU1 forms the first display area 51, and the second image light C2 forms the second display area 52. When the front is viewed from the viewpoint 6, with respect to the windshield 3, as a virtual image 9 of the display area 5, a first virtual image V1 of the first display area 51 formed by the first image light C1 and a second virtual image V2 of the second display area 52 formed by the second image light C2 can be visually recognized.

[0062] In the image forming unit PGU1, an optical element 15 is arranged between the light source device 11 and the LCD 12, in the second region r2, particularly at a predetermined position close to the back side of the LCD 12 (or the incident side of the image light of the LCD 12). In the image forming unit PGU1, the light source device 11, the light source element 15, and the LCD 12 are fixed in a predetermined positional relationship. The optical element 15 is composed of a prism or a lens.

[0063] The HUD device 1 of the first embodiment has an optical system that uses a mirror M1 in common for the first image light C1 and the second image light C2. To this end, in the HUD device 1, optical adjustment is performed using the optical element 15 of the image forming unit PGU1 and the two mirrors M21 and M22. The optical adjustment is an adjustment related to the optical distance, direction, magnification, etc. up to the virtual image 9.

[0064] In addition, not limited to Figure 3 The configuration example may be various configurations related to the arrangement of the optical element 15 of the image forming unit PGU1. As a modified example, the optical element 15 may be arranged on the optical path behind the display surface sf1 of the LCD 12 as a display panel.

[0065] exist Fig.14 In FIG. 1 , a YZ plane diagram of Modification 1A is shown as a modification of Embodiment 1. Fig.14 In the second region r2 of the image forming unit PGU1 , the optical element 15 is arranged near the display surface sf1 of the LCD 12 .

[0066] As for the design and optical adjustment of the optical distance in the first display area 51 formed by the first image light C1 and the second display area 52 formed by the second image light C2, various structural examples can be realized by using the optical element 15, other lenses, etc. As a basic idea, the following structure can be realized: in the optical path of the first image light C1 and the optical path of the second image light C2, the virtual image optical system is designed based on the optical path of one side, and the optical path of the other side is optically adjusted by using the optical element 15, other lenses, etc. Figure 3 In the example, based on the optical path of the first image light C1, the optical element 15 is not provided in the first region r1, and the optical element 15 is provided in the second region r2, thereby optically adjusting the optical distance and direction of the optical path of the second image light C2.

[0067] As a modification of the first embodiment, a lens for optical adjustment or the like may be arranged as another additional component on the optical path from the display surface sf1 of the image forming unit PGU1 to the mirrors M21 and M22 .

[0068] exist Fig.15In FIG. 1 , a YZ plane diagram of Modification 1B is shown as a modification of Embodiment 1. Fig.15 In Figure 3 Similarly, in the optical path to the mirrors M21 and M22 in the subsequent stage of the display surface sf1 of the image forming unit PGU1, the first lens L1 is arranged on the optical path of the first image light C1 in the first region r1, and the second lens L2 is arranged on the optical path of the second image light C2 in the second region r2. In this way, 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.

[0069] In this modification 1B, first, optical adjustment is performed with respect to the directions of the two image lights C1 and C2, etc., using the optical element 15, and optical adjustment is also performed with the subsequent lenses L1 and L2. As the optical adjustment performed with the lenses L1 and L2, adjustment of the optical distance and the like is listed. In addition, in this modification 1B, the optical element 15 is used to adjust the directions of the two image lights C1 and C2 in the same manner as in the first embodiment so that the directions are expanded toward the two mirrors M21 and M22, so it is also easy to configure the two lenses L1 and L2.

[0070] In other variations, the optical distance etc. may be designed based on the optical path of one of the first image light C1 and the second image light C2 (for example, image light C1), and a lens etc. (for example, lens L2) for optical adjustment may be provided only on the optical path of the other image light (for example, image light C2).

[0071] The HUD device 1 of the first embodiment is as follows Figure 3 , described later Figure 4 In this way, the effective area of ​​the display surface sf1 of the LCD 12 is divided into two areas, namely, the first area r1 and the second area r2. The virtual image V1 of the first display area 51 is formed by the first image light C1 from the first area r1, and the virtual image V2 of the second display area 52 is formed by the second image light C2 from the second area r2. The second virtual image V2 of the second display area 52 based on the second image light C2 has a shorter virtual image distance than the first virtual image V1 of the first display area 51 based on the first image light C1. With respect to the second image light C2 for the second display area 52, the light angle of the light source light from the light source device 11 is bent by the optical element 15 arranged near the back side of the LCD 12, thereby separating the optical path for the first image light C1.

[0072] When the optical element 15 is constituted by a lens instead of a prism, the lens is disposed at a position eccentric from the optical axis of the second image light C2 .

[0073] The first image light C1 and the second image light C2 are reflected by different folding mirrors, namely, mirrors M21 and M22. The mirrors M21 and M22 are designed in positions and directions so as to reflect the first image light C1 and the second image light C2 toward a common concave mirror M1.

[0074] In the HUD device 1 of embodiment 1, as a design of the optical system, in the optical path of the first image light C1 for forming the virtual image V1 of the first display area 51 and the optical path of the second image light C2 for forming the virtual image V2 of the second display area 52, the optical path of the second image light C2 is shorter in length and has a shorter virtual image distance than the optical path of the first image light C1.

[0075] exist Figure 3 In the example of the design of two display areas 5 (51, 52) based on the virtual image optical system, the first display area 51 is formed on the rear side (vehicle front side) in the Y-axis direction compared with the second display area 52, and the first display area 51 is formed on the upper side in the Z-axis direction compared with 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 structure of being folded back by the mirror M21. Therefore, the first display area 51 is formed on the rear side (vehicle front side) in the Y-axis direction compared with the second display area 52. In addition, the following structure is formed: the position of the irradiation of the first image light C1 to the mirror M1 becomes the lower side in the Z-axis direction compared with the irradiation position of the second image light C2. Therefore, the first image light C1 projected from the mirror M1 to the windshield 3 becomes a position higher than the second image light C2. Thus, the first display region 51 is formed on the upper side of the second display region 52 in the Z-axis direction.

[0076] like Figure 3 In this way, the HUD device 1 of the first embodiment can form a hierarchical display area 5 composed of two display areas 51 and 52, and can display respective virtual images 9 (V1, V2) in the two display areas 51 and 52. In the HUD device 1 of the first embodiment, the virtual image V1 can be displayed only in the first display area 51, the virtual image V2 can be displayed only in the second display area 52, or the virtual images V1 and V2 can be displayed in both display areas 51 and 52 at the same time.

[0077] exist Figure 3 In the design example of the display area 5 and the virtual image optical system, when viewed from the viewpoint 6, the first display area 51 and the second display area 52 are arranged to partially overlap in the vertical direction corresponding to the Z axis (described later). Figure 5That is, when viewed from the viewpoint 6, a portion of the lower side of the first display area 51 overlaps a portion of the upper side of the second display area 52. Without limitation, when viewed from the viewpoint 6, the first display area 51 and the second display area 52 may be separated in the vertical direction corresponding to the Z axis (described later). Figure 6 ).

[0078] By adjusting the design of the optical system, for example, by adjusting the shape, position, and orientation of the optical element 15 of the image forming unit PGU1, and the positions and orientations of the two mirrors M21 and M22, the arrangement relationship of the virtual images 9 of the two display areas 5 can be realized.

[0079] [About polarized light design]

[0080] exist Figure 3 In the HUD device 1 of embodiment 1, the first image light C1 and the second image light C2 projected onto the surface sf6 of the windshield 3 are as follows as an example of the design of the characteristics of polarized light. The first image light C1 is set to be light that is incident on the surface sf6 of the windshield 3 as S-polarized light (also recorded as the first polarized light). The second image light C2 is set to be light that is incident on the surface sf6 of the windshield 3 as S-polarized light (first polarized light). In addition, in the accompanying drawings, (S) is sometimes used to represent S polarized light, and (P) is used to represent P polarized light. S polarized light (or S wave) is light in which the electric field vibrates in a direction perpendicular to the incident plane, and S means perpendicular (senkrecht). P polarized light (or P wave) is light in which the electric field vibrates within the incident plane, and P means parallel (parallel). The first polarized light and the second polarized light are linear polarized lights that are orthogonal to each other.

[0081] In accordance with such a design, the image forming unit PGU1 is an image display device that generates and emits the first image light C1 which is S-polarized light and the second image light C1 which is S-polarized light.

[0082] The following may be cited as a modified example. It may also be configured so that the characteristics of the vibration direction, that is, the characteristics of the S polarized light and the P polarized light, are reversed in the first image light C1 and the second image light C2 from the image forming unit PGU1. In this case, the virtual image V1 of the first display area 51 and the virtual image V2 of the second display area 52 are formed by the image light of the P polarized light.

[0083] [Image forming unit]

[0084] Figure 4 Show about including Figure 3 A perspective view of a structural example of the image forming unit PGU1 of the optical element 15. Figure 4In addition to the spatial coordinate system (X, Y, Z), a coordinate system (x, y, z) based on the display surface sf1 of the LCD 12 of the image forming unit PGU1 is also shown. The x-axis direction is the horizontal direction in the screen of the display surface sf1 (in other words, the lateral direction), the y-axis direction is the vertical direction in the screen of the display surface sf1 (in other words, the longitudinal direction), and the z-axis direction is the direction perpendicular to the xy plane formed by these.

[0085] In the space combining 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, the space is divided into two regions with the dashed line shown in the figure as the boundary for the convenience of explanation, and they are recorded as a first region r1 and a second region r2. The first region r1 and the second region r2 in the xy plane on the emission side of the light source device 11 are respectively shown in the figure with a dashed rectangle, and the first region r1 and the second region r2 in the xy plane on the emission side of the LCD 12, that is, the display surface sf1, are respectively shown in the figure with a dashed rectangle.

[0086] In the space combining the xy plane of the emission side of the light source device 11 and the xy plane of the incident side of the LCD 12, the optical element 15 is arranged in the second region r2. In this example, as shown in the figure, the optical element 15 is composed of a prism having a roughly triangular prism shape. The axis of the triangular prism shape of the optical element 15 is arranged along the x-axis direction corresponding to the horizontal side of the LCD 12. The cross-section (yz plane) of the triangular prism shape of the optical element 15 roughly has a right triangle as shown in the figure. With respect to the right triangle, one side forming a right angle is arranged close to the xy plane on the back side of the LCD 12, and the hypotenuse of the side not forming a right angle is arranged toward the emission surface sf11 side of the light source device 11.

[0087] The light source device 11 emits light source light in the z-axis direction from the emission surface sf11. The light source light in the first region r1 of the light source device 11 is incident on the back side of the LCD 12 without passing through the optical element 15, as indicated by the single-dot-dash arrow on one side indicating the optical axis. The LCD 12 uses the light source light in the first region r1 as backlight, and emits the first image light C1 according to the image displayed in the first region r1 on the display surface sf1. On the other hand, the light source light in the second region r2 of the light source device 11 is incident on the back side of the LCD 12 via the optical element 15, as indicated by the single-dot-dash arrow on the other side indicating the optical axis. The LCD 12 uses the light source light in the second region r2 as backlight, and emits the second image light C2 according to the image displayed in the second region r2 on the display surface sf1.

[0088] The first image light C1 emitted from the first region r1 in the display surface sf1 has an optical axis along the z-axis direction. The second image light C2 emitted from the second region r2 in the display surface sf1 has an optical axis inclined upward at a predetermined angle θ relative to the z-axis direction. Thus, the first image light C1 and the second image light C2 advance in an optical path that is separated and expanded toward the two mirrors M21 and M22.

[0089] Furthermore, a diffusion plate or the like may be further provided in a space in front of the optical element 15 at a subsequent stage of the light source device 11 .

[0090] [HUD display area]

[0091] Figure 5 and Figure 3 Correspondingly, a schematic structure of the display area 5 (51, 52) formed by the image display unit 200 of the HUD device 1 of the first embodiment is shown in the XZ plane when the windshield 3 is viewed from the front (Y-axis direction) from the driver's viewpoint 6. Figure 5 , the two display areas 51 and 52 are schematically shown formed by the image light (the above-mentioned image light C1 and C2) reflected / projected from the concave mirror M1 to the windshield 3. Figure 5 In particular, the case where two display areas 51 and 52 are formed to partially overlap in the up-and-down direction (Z-axis direction) in the direction viewed from the viewpoint 6 is shown.

[0092] In the effective area of ​​the reflecting surface sf5 of the concave mirror M1, a portion of the lower side includes an area 401 illuminated by the first image light C1 from the mirror M21, and a portion of the upper side includes an area 402 illuminated by the second image light C2 from the mirror M22. The first display area 51 is formed on the upper side by the reflected first image light C1 from the area 401, and the second display area 52 is formed on the lower side by the reflected second image light C2 from the area 402.

[0093] exist Figure 5 In the configuration example, in the effective area of ​​the reflecting 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. Figure 3 As shown, the images passed through the mirrors M1, M21, M22, etc. have an inverted relationship, so the first image light C1 from the lower area 401 in the reflecting surface sf5 of the mirror M1 forms a virtual image V1 of the upper first display area 51, and the second image light C2 from the upper area 402 forms a virtual image V2 of the lower second display area 52.

[0094] exist Figure 6In the figure, as a modification example related to the formation of the display area 5, in particular, a case is shown in which two display areas 51 and 52 are formed separately and without overlapping in the vertical direction (Z-axis direction) in the direction observed from the viewpoint 6. In the effective area of ​​the reflecting surface sf5 of the concave mirror M1, there is an area 401 irradiated by the first image light C1 in a part of the lower side, and there is an area 402 irradiated by the second image light C2 in a part of the upper side. The first display area 51 is formed by the first image light C1 from the area 401, and the second display area 52 is formed by the second image light C2 from the area 402. Figure 6 In the configuration example, in the effective area of ​​the reflecting surface sf5 of the concave mirror M1, the area 401 where the first image light C1 is reflected and the area 402 where the second image light C2 is reflected are separated.

[0095] like Figure 5 As in the HUD device 1 of the first embodiment, the components for reflecting the two image lights C1 and C2 from the image forming unit PGU1 are partially common to the concave mirror M1. In the effective area of ​​the reflection surface sf5 of the concave mirror M1, how the area irradiated by the two image lights C1 and C2 is constructed is not limited to Figure 5 , Figure 6 A structural example of , and a modified example are described later.

[0096] [About sunlight countermeasures]

[0097] The HUD device 1 of the first embodiment has the following solution for sunlight countermeasures, etc. The function and structure related to the sunlight countermeasures are constituted by a combination of a polarization element and an infrared (IR) cutoff as described below.

[0098] First, the structure of the polarization element is as follows. Figure 3 In the embodiment, the dust cover 71 provided at the opening of the frame 60 is made of transparent plastic, and an absorption type polarization element is provided on the surface of the transparent plastic. The absorption type polarization element is an element whose absorption axis is orthogonal to the image light (the first image light C1 and the second image light C2).

[0099] In addition, a reflective polarizing element or an absorption type changing element is provided as an optical element immediately after the display surface sf1 of the LCD 12 in the image forming unit PGU1. The reflective polarizing element is an element whose reflection axis is orthogonal to the image light (the first image light C1 and the second image light C2). The absorption type changing element is an element whose absorption axis is orthogonal to the image light (the first image light C1 and the second image light C2).

[0100] exist Fig.16 In the embodiment, a configuration example related to the above-mentioned polarization element is shown as a modification 1C. Fig.16In the example of FIG. 1 , an absorption type changing element is arranged as the optical element 16 immediately after the display surface sf1 of the LCD 12. The absorption type changing element absorbs components other than the S-polarized light with respect to the first image light C1 and the second image light C2.

[0101] As a modification example of the above-described polarizing element, the display surface sf1 of the LCD 12 may be divided into a first region r1 and a second region r2 , and polarizing elements may be disposed in each region.

[0102] The structure related to IR cutoff is as follows, for example. First, an IR absorbing function is provided in the dust cover 71. For example, an IR absorbing sheet is provided in the dust cover 71 as one layer.

[0103] The mirrors M21 and M22 are formed of cold mirrors. A cold mirror is a mirror that transmits infrared light and reflects visible light. The visible light reflected by the cold mirror is the first image light C1 and the second image light C2.

[0104] In the absence of a structure for taking measures against sunlight, when external light such as sunlight enters the frame 60 through the dust cover 71 of the opening, there is a possibility that the incident external light is reflected by the concave mirror M1 and the reflected external light enters the display surface sf1 of the image forming unit PGU1. In this case, the external light is particularly incident on the surface of the LCD 12 as a display panel, which may affect the panel burnout, which is undesirable. For this reason, the function / structure for taking measures against sunlight as described above is provided in Embodiment 1.

[0105] exist Fig.16 In the figure, consider the case where external light such as sunlight passes through the dust cover 71 in the direction opposite to the direction of the image light C1 and C2 and enters the frame 60. Regarding the external light, first, the IR component is cut off due to the IR absorption function of the dust cover 71. There is a case where the external light is reflected by the concave mirror M1, and part of the reflected external light is further reflected by the mirror M21 and the mirror M22. At this time, the cold light mirror as the mirror M21 and the mirror M22 cuts off the IR component of the incident external light. There is a case where part of the external light reflected by the mirror M21 and the mirror M22 further goes toward the image forming unit PGU1 and enters the display surface sf1. At this time, the reflective polarization element or the absorption type change element as the optical element 16 arranged on the front surface side of the LCD 12 reflects or absorbs the external light. As a result, the external light reaching the display surface sf1 of the LCD 12 is reduced. Therefore, panel burnout of the LCD 12 can be prevented or reduced.

[0106] [About the optical path cutoff function and protection mode]

[0107] exist Figure 7 In, with Figure 3 Similarly, a schematic diagram for explaining the optical path blocking function (in other words, the external light incident prevention function, etc.) and the protection mode of the image display unit 200 in the HUD device 1 of the first embodiment is shown in the YZ plane. Figure 3 Based on the structure of the image forming unit PGU1, mirrors M21, M22, and M1, there is also a light path cutting function related to sunlight countermeasures. The light path cutting function is as follows: the light path of incident external light such as sunlight is cut off on the light path from the dust cover 71 to the image forming unit PGU1, especially to prevent external light from being incident on the display surface sf1 of LCD12. This function is to rotate the mirror M1 according to a control mode (sometimes recorded as a protection mode, etc.) to prevent the external light from being incident on the display surface sf1 of the image forming unit PGU1, thereby shifting the direction of the light path of the external light. In other words, it is a function to change the direction of the light path of the external light. This function can prevent the panel of LCD12 from being burned out, etc.

[0108] exist Figure 7 In the embodiment, the concave mirror M1 is provided with a rotation axis and a driving mechanism 61 such as a motor. The rotation axis of the driving mechanism 61 is an axis extending in the X-axis direction corresponding to the left-right direction of the vehicle, and the concave mirror M1 can be rotated around the rotation axis by driving a motor or the like connected to the rotation axis. By rotating the concave mirror M1 using the driving mechanism 61, the direction of the concave mirror M1 can be changed. In the first embodiment, the rotatable mechanism of the mirror M1 can be connected to the vertical direction 5a ( Figure 5 The device also shares a mechanism for adjusting the formation position of the display area 5 (etc.).

[0109] First, the HUD device 1 sets the state of the concave mirror M1 to the state A shown by the dotted line in the normal display mode. In the state A, the optical axes of the image lights C1 and C2 used for the respective display areas 51 and 52 are shown as the single-dot chain arrows. In the normal display mode, the external light incident optical path in the reverse direction relative to the direction of the optical axes of the image lights C1 and C2 is considered. The external light a100 as the sunlight a100 shown by the dotted arrow in the figure represents the optical axis in the external light incident optical path. The external light a101 represents the optical path of the external light in the reverse direction relative to the optical path of the first image light C1, and the external light a102 represents the optical path of the external light in the reverse direction relative to the optical path of the second image light C2. When the external light a100 (a101, a102) as the sunlight in the external light incident optical path passes through the dust cover 71 and enters the frame 60, it is reflected by the mirror M1 and moves in the reverse direction of the optical paths of the respective image lights C1 and C2. These external lights are reflected by the mirrors M21 and M22, and are directed toward the image forming unit PGU1, and are incident on the display surface sf1. This may affect the panel burn-in of the LCD 12, so it is necessary to take countermeasures.

[0110] In the HUD device 1 of the first embodiment, as a function for cutting off the optical path of the external light a100 as shown in the figure incident on the image forming unit PGU1, a function of switching from the normal display mode to the protection mode is provided. In the protection mode, the HUD device 1 of the first embodiment rotates the mirror M1 based on the driving mechanism 61 to the state B shown by the solid line. The mirror M1 rotates from the state A to the front side (the rear side of the vehicle) in the Y-axis direction at a predetermined angle around the rotation axis, thereby reaching the state B.

[0111] Thus, in the protection mode, the external light a101 and the external light a102 as the sunlight a100 entering the frame 60 through the dust cover 71 are respectively reflected by the mirror M1 in the state B and then travel as the external light a103 and the external light a104. Figure 3 ) to deviate the direction of the optical path. Regarding the external light a104 based on the external light a102, in order to prevent the external light a104 from irradiating the surface sf22 ( Figure 3 ) to shift the direction of the light path.

[0112] More specifically, the optical path of the external light a103 is toward the surface sf21 ( Figure 3 ) and is offset downward in the Z-axis direction. The external light a103 is not reflected by the mirror M22, so it does not enter the display surface sf1 of the image forming unit PGU1. In addition, the optical path of the external light a104 is toward the surface sf22 ( Figure 3 ) and is shifted downward in the Z-axis direction. The optical path of the external light a104 irradiates the surface sf21 ( Figure 3 ), but the optical path of the external light a105 after the external light a104 is reflected by the 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. That is, the direction of the optical path of the external light a105 based on the external light a102 is also offset in such a way as to prevent it from being irradiated to the display surface sf1 of the image forming unit PGU1.

[0113] As described above, in the protection mode, the HUD device 1 of the first embodiment controls the direction of the optical path of the reflected external light to be changed according to the rotation of the concave mirror M1 in order to prevent the external light from being incident on the display surface sf1 of the image forming unit PGU1. Thus, the image forming unit PGU1, especially the panel surface of the LCD 12, is protected from being deteriorated.

[0114] The mechanism for shifting the direction of the optical path of the external light by the rotation of the mirror M1, in other words, the mechanism for blocking the external light incident on the image forming unit PGU1, may not be limited to Figure 7 Such a configuration example may be a configuration in which the external light a103 and a104 reflected from the concave mirror M1 is changed in the direction of the optical path so as not to be incident on the display surface sf1 of the image forming unit PGU1 in the end, regardless of whether the external light a103 and a104 are irradiated on the mirrors M21 and M22 .

[0115] exist Fig.17 In the embodiment, a modification example 1D related to the above-mentioned optical path cutting function is shown as a modification example of the first embodiment. In this modification example 1D, Figure 7 Compared with the structural example of , two mirrors M21 and M22 are arranged at a wider interval in the Z-axis direction. Corresponding to the arrangement of these mirrors M21 and M22, the optical element 15 is used to design the difference in the angle of the direction to be larger for the two image lights C1 and C2 from the display surface sf1 of the image forming unit PGU1. In this modified example 1D, in the protection mode, when the concave mirror M1 is in the state B, according to the incidence of the external light a100 (a101, a102), the optical path directions of the external light a103 and the external light a104 reflected by the concave mirror M1 are offset in a manner to prevent them from being irradiated to the mirrors M21 and M22.

[0116] Specifically, the optical path direction of the external light a103 based on the external light a101 is toward the position below the mirror M21. The optical path direction of the external light a104 based on the external light a102 is toward the position below the mirror M22, especially the space between the mirrors M22 and M21. Figure 7 Therefore, in the modification 1D, it is possible to prevent external light from being incident on the display surface sf1 of the image forming unit PGU1 even in the protection mode.

[0117] In the first embodiment, the direction of rotation of the mirror M1 is as follows: Figure 7 In that way, the direction of rotation of the mirror M1 is set to be inclined from the rear side to the front side in the Y-axis direction, thereby forming a structure in which the direction of the optical axis of the external light reflected from the concave mirror M1 is offset to the downward side relative to each mirror M21 and M22, such as the external light a103 and the external light a104. It may not be limited to this. In a modified example, the direction of rotation of the mirror M1 may also be set to be inclined from the front side to the rear side, thereby forming a structure in which the direction of the optical axis of the external light reflected from the concave mirror M1 is offset to the upward side relative to each mirror M21 and M22. However, in this case, the reflecting surface sf5 of the mirror M1 faces further upward, so there is a possibility of stray light occurring in the vehicle 2, which is undesirable. Therefore, in Embodiment 1, the direction of rotation of the mirror M1 is configured as described above to be inclined to the front side.

[0118] As described above, the HUD device 1 is driven and controlled in such a manner that the mirror M1 is in the first state (state A) in the normal display mode and in the second state (state B) in the protection mode. Regarding the control such as switching to the protection mode, for example, the following two cases can be listed. As the first case, the HUD device 1 is in the protection mode when not in use or when the virtual image 9 is not displayed, and is in the normal display mode when the virtual image 9 is displayed. In addition, even when the ignition switch of the vehicle 2 is in the off state, the HUD device 1 is in the protection mode to protect the image forming unit PGU1 and cuts off the incident light path of the external light.

[0119] As a second case, the HUD device 1 detects external light incidence based on the sensor as described later even in the normal display mode, and automatically switches to the protection mode when it is determined that external light incidence should be avoided from the perspective of temperature. This is a control that gives priority to avoiding external light incidence and preventing panel burnout over displaying the virtual image 9.

[0120] [Installation example]

[0121] Figure 8 FIG. 2 shows an example of installing the frame 60, the image forming unit PGU1, the mirror M21, the mirror M1, the dust cover 71, etc. in the image display unit 200. Figure 8 In FIG. 1 , among the two mirrors M21 and M22 , only one mirror M21 is shown, and the other mirror M22 is omitted.

[0122] In addition, Figure 8 In the installation example of FIG. 7 , a sunlight sensor 66 is provided near the dust cover 71. The sunlight sensor 66 detects the incidence of external light such as sunlight a100 in a detection range such as a range 66a.

[0123] [About temperature detection unit and sunlight countermeasures]

[0124] Fig. 9 yes Figure 7 Schematic diagram of the light path cutoff function and the temperature control using the sunlight sensor 66 and the like in the protection mode. Fig.11 ), the control unit 101 of the HUD device 1 further includes a protection processing unit 1060, which is used to Figure 8 The part that uses the detection information of the sunshine sensor 66 to perform temperature detection, protection processing, etc. Fig. 9 An example of the processing content of the protection processing unit 1060 is shown in FIG. Fig. 9 In, extract Figure 3 , Figure 7Among them, the image forming unit PGU1 is mainly shown in the figure, and the dust cover 71, the sunlight sensor 66, the mirror M1, etc. are simply shown in the figure.

[0125] exist Fig. 9 In the image forming unit PGU1, the image forming unit PGU1 is configured to have a light source device 11 and an LCD 12 as a display device. In the normal display mode, the external light a100 as sunlight a100 is reflected by the concave mirror M1 to become external light a901 and external light a902. The external light a901 is reflected by the mirror M21 to become external light a903, and the external light a902 is reflected by the mirror M22 to become external light a904. The external light a903 and the external light a904 are directed toward the display surface sf1 of the LCD 12 of the image forming unit PGU1.

[0126] First, the temperature (set to TP1) of LCD12 possessed by the image forming unit PGU1 can be estimated based on the ambient temperature Ta of the image forming unit PGU1, the temperature rise ΔT(I) associated with the external light a910 (a903, a904) incident on LCD12, and the temperature rise ΔT(L) associated with the thermal radiation from the light source device 11.

[0127] In simple terms, it can be assumed that the ambient temperature Ta, the temperature rise amount ΔT(I), the temperature rise amount ΔT(L), etc. in the first area r1 and the second area r2 of the image forming unit PGU1 are of the same degree, and the temperature TP1 of the LCD 12 in each area can be estimated by the same mechanism. In detail, the ambient temperature Ta, the temperature rise amount ΔT(I), the temperature rise amount ΔT(L), etc. can be set to be different in the first area r1 and the second area r2 of the image forming unit PGU1, and the temperature of the LCD 12 in each area can be estimated.

[0128] HUD device 1 Fig.11 The protection processing unit 1060 performs the following processing. First, the temperature sensor provided in the HUD device 1 or the temperature sensor 912 ( Fig.10 ) to detect the ambient temperature Ta of the image forming unit PGU1. The protection processing unit 1060 understands the ambient temperature Ta of the image forming unit PGU1 based on the detection information of the temperature sensor.

[0129] Next, the temperature rise ΔT(I) associated with the sunlight a100 can be calculated based on the sunlight intensity detected by the sunlight sensor 66. The protection processing unit 1060 calculates the temperature rise ΔT(I) associated with the external light a910 of the image forming unit PGU1 based on the detection information of the sunlight sensor 66.

[0130] Next, the temperature rise amount ΔT(L) associated with the heat radiation from the light source device 11 can be calculated based on the brightness or light amount of the backlight set by the light source device 11, for example, the duty ratio of the pulse width modulation (PWM) control of the light source driving unit 1022. The protection processing unit 1060 calculates the temperature rise amount ΔT(L) associated with the heat radiation from the light source device 11 of the image forming unit PGU1.

[0131] In the control example in the first embodiment, a calculation formula for finding the temperature rise amount ΔT(I) on the LCD 12 side is set separately according to the difference between the first region r1 and the second region r2. The respective calculation formulas are represented by calculation formulas G1 and G2. In addition, as a modified example, as a simple structure, the calculation formula for finding the temperature rise amount ΔT(I) in the first region r1 and the second region r2 of the image forming unit PGU1 may be set to the same calculation formula.

[0132] As described above, the protection processing unit 1060 indirectly detects the temperature TP1 of the display surface of LCD 12 by calculating the ambient temperature Ta of the image forming unit PGU1, the temperature rise ΔT(I) of LCD 12 caused by sunlight, and the temperature rise ΔT(L) from the light source device 11.

[0133] Here, the temperature rise amount ΔT(L) associated with the heat radiation from the light source device 11 is a parameter that can be controlled by the brightness or light amount of the backlight. That is, the brightness or light amount of the backlight of the light source device 11 has a predetermined relationship with 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 amount of the backlight of the light source device 11.

[0134] Therefore, the control unit 101 of the HUD device 1 performs control in a manner to adjust the brightness or light amount 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 value, and adjusts the brightness or light amount of the backlight of the light source device 11 when the threshold value is exceeded. For example, when the detected temperature TP1 exceeds the set threshold value Th1, the control unit 101 performs drive control in a manner to reduce the brightness or light amount of the backlight of the light source device 11, that is, to reduce the duty cycle of the PWM control. In this way, the temperature rise of the LCD 12 in the image forming unit GPU1 can be suppressed.

[0135] [Vehicle information and sensors]

[0136] Fig.10 The vehicle information acquisition unit 1015 ( Fig.11 ) or the control unit 100 of the vehicle 2 obtains Figure 1An example of the structure of a sensor etc. of vehicle information 4. Fig.10 , examples of various sensors connected to the vehicle information acquisition unit 1015 or the control unit 100, in other words, information acquisition devices, measuring devices, communication devices, etc. are shown. For example, the control unit 100 acquires vehicle information 4 from sensors provided in various parts of the vehicle 2. For example, various sensors periodically detect parameter values ​​related to conditions such as driving conditions in the interior and exterior of the vehicle 2. In addition, the control unit 100 determines / detects various events related to the vehicle 2 based on the detection information of the sensors.

[0137] The vehicle information 4 is a general term for information related to the driving conditions of the vehicle 2. The vehicle information 4 includes ADAS information, etc. The vehicle information 4 includes, for example, speed information of the vehicle 2, gear information, steering wheel steering angle information, light lighting information, external light information, distance information, infrared information, engine ON / OFF information, camera image information, acceleration gyro information, GPS (Global Positioning System) information, navigation information, vehicle-to-vehicle communication information, and road-to-vehicle communication information. The camera image information includes in-vehicle camera image information and out-vehicle camera image information. The GPS information includes current time information, latitude, and longitude information.

[0138] exist Fig.10 In the present invention, various sensors include a vehicle speed sensor 901, a displacement position sensor 902, a steering wheel steering angle sensor 903, a headlight sensor 904, an illumination 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 wireless transceiver for road-to-vehicle communication 913, a wireless transceiver for vehicle-to-vehicle communication 914, an in-vehicle camera 915, an out-vehicle camera 916, a GPS receiver 917, and a VICS (Vehicle Information and Communication System, a Japanese registered trademark) receiver 918. Various sensors are not limited to these, and can be added, deleted, replaced, etc.

[0139] The vehicle speed sensor 901 detects the speed of the vehicle 2 (also recorded as the vehicle speed) and generates speed information as a detection result. The shift position sensor 902 detects the current gear and generates gear information as a detection result. The steering wheel steering angle sensor 903 detects the current steering wheel steering angle and generates steering wheel steering angle information as a detection result. The headlight sensor 904 detects the on / off of the headlights and generates light lighting information as a detection result. The illuminance sensor 905 and the chromaticity sensor 906 detect external light and generate external light information as a detection result.

[0140] The distance measuring sensor 907 detects the distance between the vehicle 2 and an external object, and generates distance information as a detection result. The infrared sensor 908 detects the presence or absence of an object at a close distance to the vehicle 2, the distance, etc., and generates infrared information as a detection result. The engine start sensor 909 detects the on / off of the engine, and generates on / off information as a detection result. The acceleration sensor 910 and the gyro sensor 911 detect the acceleration and angular velocity of the vehicle 2, and generate acceleration gyro information indicating the posture and behavior of the vehicle 2 as a detection result. The temperature sensor 912 detects the temperature inside and outside the vehicle 2, and generates temperature information as a detection result.

[0141] The in-vehicle camera 915 generates in-vehicle camera image information by photographing the inside of the vehicle 2. The out-vehicle camera 916 generates out-vehicle camera image information by photographing the outside of the vehicle 2. Figure 2 The camera 90 is equivalent to the in-vehicle camera 915 and the out-vehicle camera 916. The in-vehicle camera 915, for example, captures the driver's posture, eye position, activities, etc., and constitutes a DMS (Driver Monitoring System). By analyzing the in-vehicle camera image information, the driver's fatigue status, line of sight, etc. can be grasped. In addition, the out-vehicle camera 916, for example, captures the surrounding conditions in front of the vehicle 2. By analyzing the out-vehicle camera image information, the presence or absence of other vehicles or people around the vehicle 2, buildings or terrain, rain or snow, ice, bumps, and other road conditions, as well as road signs, etc. can be grasped. In addition, the out-vehicle camera 916 also includes a driving recorder that records the driving conditions in the form of images.

[0142] The wireless transceiver 913 for road-to-vehicle communication generates road-to-vehicle communication information through road-to-vehicle communication between the vehicle 2 and the road, signs, signal equipment, etc. The wireless transceiver 914 for vehicle-to-vehicle communication generates vehicle-to-vehicle communication information through vehicle-to-vehicle communication between the vehicle 2 and other vehicles in the surrounding area. 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 can also be set as part of the navigation system.

[0143] [Function block]

[0144] Fig.11 FIG. 2 shows an example of a functional block structure of the HUD device 1. Fig.11 In the structural example of Figure 3 Such image forming unit PGU1 and concave mirror M1 have a display driver 1021 and a light source driver 1022, etc. In this configuration example, an image processing unit 1013 connected to the display driver 1021 and the light source driver 1022 is provided.

[0145] exist Fig.11 In the HUD device 1, a control unit 101, an image display unit 200, a mirror driving unit 1020, a display driver 1021, a light source driving unit 1022, a sound driver 1025, a sound output device 1041, a sound input device 1042, etc. The control unit 101 has an MCU (micro control unit) 1010, a non-volatile memory 1011, a volatile memory 1012, an image processing unit 1013, a sound processing unit 1014, a vehicle information acquisition unit 1015, a communication unit 1016, an operation input unit 1017, a protection processing unit 1060, etc. These units are connected to each other via a bus or the like, and can perform input and output and communication with each other.

[0146] The control unit 101 is a controller or a control device. The control unit 101 implements control functions based on the processing of the processor. The control function is a function of controlling the entire HUD device 1 and each part, including a function of displaying a virtual image 9 in the display area 5. The control unit 101 implements the function through software program processing or a dedicated circuit.

[0147] The storage unit of the HUD device 1 is configured to include a nonvolatile memory 1011 and a volatile memory 1012. Various data and information handled by the control unit 101 and the like including computer programs are stored in the storage unit.

[0148] The communication unit 103 is a device equipped with a communication interface and can connect and communicate with the control unit 100 (eg, electronic control unit: ECU) via an interface such as CAN (Controller Area Network) or LIN (Local Interconnect Network) of the vehicle 2 .

[0149] The mirror driving unit 1020 is a device that drives the driving mechanism 61 of the concave mirror M1 according to the control from the control unit 101 .

[0150] The display driver 1021 is a device including a drive circuit and the like that drives the LCD 12 of the image forming unit PGU1 according to control from the control unit 101 .

[0151] The light source driving unit 1022 includes a driving circuit and the like that drives the light source device 11 of the image forming unit PGU1 according to the control from the control unit 101. The light source driving unit 1022 includes a driving circuit and the like that can change the on / off state of light emission and the light intensity of each light source element of the light source device 11.

[0152] The sound input device 1042 is composed of a microphone and a circuit, etc. The sound output device 1041 is composed of a speaker and a circuit, etc. In addition, the HUD device 1 is shown as having the sound input device 1042 and the sound output device 1041, but is not limited to this. The HUD device 1 can also use the sound input device 1042 and the sound output device 1041 connected to the inside of the vehicle 2 (for example, the control unit 100) outside.

[0153] Fig.11 The control unit 101 in the embodiment obtains the vehicle information 4 ( Figure 1 ), ADAS information, event information and other input information. Alternatively, the control unit 101 obtains the vehicle information 4 ( Figure 1 ), ADAS information, event information and other input information as CAN signals. The vehicle information acquisition unit 1015 can also be installed integrally with the communication unit 103. The input information includes Fig.10The input information also includes, for example, information about objects in the real scene detected based on the image of the camera 90, warning information for superimposing the objects, and navigation information. The control unit 101 generates image data / image information for displaying the virtual image 9 in the display area 5 as required based on such input information through a control function. The control unit 101 generates an image signal for controlling the display driver 1021 and the like based on the image data / image information.

[0154] In addition, the control unit 101 may also obtain the user's operation input information via the operation input unit 1017. As the operation input unit 1017, a remote controller or the like may be cited. In addition, when the HUD device 1 performs sound output, the control unit 101 generates sound output information and controls the sound driver 1025. In addition, when the voice of a user such as a driver is input, the control unit 101 performs sound recognition based on the input sound of the sound input device 1042 and accepts a predetermined instruction or the like.

[0155] Not limited to Fig.11 In the configuration example, the HUD device 1 may include, for example, a sunlight sensor 66 ( Figure 8 ) etc. The control unit 101 may also use the detection information of the sensor to judge / detect the state of the HUD device 1 and the state near the HUD device 1 to perform predetermined control.

[0156] also, Fig.11 The control unit 101 and other components can be mounted on Figure 3 The image display unit 200 may be inside the frame 60 or may be connected to the outside of the frame 60 .

[0157] [Image display control example]

[0158] As Fig.11 The following are examples of image display control by the control unit 101. The control unit 101 generates image data for displaying a virtual image 9 in the display area 5 based on the vehicle information 4 as input information, input image data, etc. For example, the HUD device 1 decides to display an AR-based navigation image and a warning image as a first virtual image V1 in the first display area 51, and at the same time displays non-AR distance information, vehicle speed information, etc. as a second virtual image V2 in the second display area 52. To this end, the control unit 101 generates the first image data with the first area r1 of the LCD 12 of the image forming unit PGU1 as the output destination, and the second image data with the second area r2 as the output destination.

[0159] The control unit 101 also performs distortion correction, turning on / off the light source, and adjusting the light quantity, etc., taking into account the difference in curvature of the windshield 3, based on the image data of the display source. The control unit 101 drives and controls the display driver 1021 and the light source driver 1022 based on the image data. The display driver 1021 drives the LCD 12 based on the signal from the control unit 101. The light source driver 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 area r1 and the second area r2 of the display surface sf1 of the LCD 12, respectively. The image forming unit PGU1 emits the first image light C1 based on the light source light from the light source device 11 and the image formed in the first area r1 of the LCD 12, and emits the second image light C2 based on the light source light from the light source device 11 and the image formed in the second area r2 of the LCD 12.

[0160] in addition, Fig.11 As described above, the protection processing unit 106 of the control unit 101 performs processing corresponding to the control of switching between the normal display mode and the protection mode based on the detection information of the sunlight sensor 66.

[0161] [Configuration Example of Image Forming Unit]

[0162] Examples of the mounting structure of the image forming unit GPU1 of the image display device 10 include the following. Fig.12 An example of the mounting structure of the image forming unit PGU1 is shown. Fig.12 The image forming unit PGU1 includes a light source device 11 and an LCD 12. The light source device 11 includes an LED substrate 201, an LED element 202, a reflector 203, a heat sink 204, a polarization conversion element 205, a light guide 206, a diffuser 206, etc. The light source device 11 is configured as a light source module by fixing these components to a housing.

[0163] A plurality of LED elements 202 are arranged on the LED substrate 201. Fig.12 In the figure, only one LED element 202 and a reflector 203 are shown. 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 manner that changes the direction and converts it into approximately parallel light. The heat sink 204 dissipates heat and cools the LED substrate 201.

[0164] The polarization conversion element 205 receives the substantially parallel light from the reflector 203, performs polarization conversion in such a manner that the polarization characteristics are consistent, and outputs the substantially parallel light after polarization conversion to the light guide 206. For example, the polarization conversion element 205 is formed by combining a polarization conversion prism and a wave plate. In the first embodiment, the polarization conversion in the polarization conversion element 205 in the image forming unit PGU1 is a polarization conversion for making the polarization consistent with the absorption axis of the polarizer on the incident side of the LCD 12.

[0165] The light guide 206 allows substantially parallel light from the polarization conversion element 205 in the first direction to enter the reflecting portion and reflect it in the second direction. The second direction is the direction toward the LCD 12. As shown in the partially enlarged view, the reflecting portion of the light guide 206 has a plurality of reflecting surfaces 206a and a plurality of connecting surfaces 206b, and each reflecting surface 206a and connecting surface 206b are alternately arranged. The reflecting portion of the light guide 206 also realizes a predetermined light distribution control. Each of the plurality of reflecting surfaces 206a has various slopes in a manner to realize a reflection direction corresponding to the predetermined light distribution control.

[0166] The light in the second direction reflected by the reflective portion of the light guide 206 is incident on the diffuser 207 and diffused by the diffuser 207. On the upper side of the diffuser 207, the panel of LCD 12 is arranged across the space containing the above-mentioned optical element 15. The panel of LCD 12 is connected to a drive circuit substrate and the like via a flexible cable. In the panel of LCD 12, light from the diffuser 207 is incident from the back side, and the light is used as backlight, and image lights C1 and C2 are emitted from the display surface sf1 on the front surface side. In the above-mentioned first region r1, the first image light C1 is generated based on the light source light of the non-transmitting optical element 15. In the above-mentioned second region r2, the second image light C2 is generated based on the light source light of the transmitting optical element 15. These image lights C1 and C2 are light beams having the above-mentioned S-polarized light and having directivity in a specific direction.

[0167] [Effects of Embodiment 1, etc.]

[0168] As described above, according to the HUD device 1 of the first embodiment, two display areas 5 (51, 52), particularly hierarchical display areas, that can display virtual images 9 can be appropriately formed. Thus, the HUD device 1 can provide the driver U1 with various virtual images 9 for driving assistance and the like using the two display areas 5 (51, 52), and can contribute to safe driving.

[0169] <Implementation Method 2>

[0170] use Fig.13The following figures illustrate the HUD device of Embodiment 2. The following mainly describes the structural parts in Embodiment 2 that are different from those in Embodiment 1. In Embodiment 2, the mirror M21 located on the lower side in the Z-axis direction among the two mirrors M21 and M22 mentioned above is composed of a concave mirror 1301. The first image light C1 reflected by the concave mirror 1301 is incident on the concave mirror M1 after being imaged once at a predetermined point P1. The point P1 of the imaging position of the mirror M21 is located near the mirror M22. In a specific example, the point P1 is at a predetermined position on the lower side relative to the mirror M22 in the Z-axis direction. By setting it as an optical system that uses the concave mirror 1301 to form an image, the image forming unit PGU1 and the mirror M21 can be arranged closer to the concave mirror M1 and the mirror M22. Through such a structure, the HUD device 1 of Embodiment 2 can further miniaturize the image display unit 200.

[0171] In Embodiment 2, as described above, the optical system uses the concave mirror 1301 to form an image in the optical path of the first image light C1, so the image relationship between the image depicted in the first area r1 and the image depicted in the second area r2 in the display surface sf1 of the LCD 12, which is the image source, becomes a vertically reversed relationship. The first image light C1 from the first area r1 is reflected by the concave mirror 1301, thereby becoming the vertically reversed image light C1 and entering the concave mirror M1. The second image light C2 from the second area r2 of the transmission optical element 15 is reflected by the mirror M22, which is a plane mirror, in the same manner as in Embodiment 1, and enters the concave mirror M1. Using the image lights C1 and C2 reflected from the concave mirror M1, virtual images 9 (V1, V2) of the two display areas 5 (51, 52) are formed for the windshield 3 in the same manner as in Embodiment 1. The virtual image V1 of the first display area 51 and the virtual image V2 of the second display area 52 are images that match each other in vertical direction when viewed from the viewpoint 6 of the driver.

[0172] [About sunlight countermeasures]

[0173] The structure for taking measures against sunlight in the HUD device 1 of the second embodiment is as follows. This structure is the same as the structure for taking measures against sunlight in the first embodiment described above, and is constituted by a combination of a polarizing element and an IR cutoff as described below.

[0174] First, the structure of the polarization element is as follows. Fig.13 In the embodiment, the dust cover 71 provided at the opening of the image display unit 200 is made of transparent plastic, and an absorption type polarization element is provided on the surface of the transparent plastic. The absorption type polarization element is an element whose absorption axis is orthogonal to the image light (the first image light C1 and the second image light C2).

[0175] In addition, a reflective polarizing element or an absorption type changing element is provided as an optical element immediately after the display surface sf1 of the LCD 12 in the image forming unit PGU1. The reflective polarizing element is an element whose reflection axis is orthogonal to the image light (the first image light C1 and the second image light C2). The absorption type changing element is an element whose absorption axis is orthogonal to the image light (the first image light C1 and the second image light C2).

[0176] exist Fig.13 1 and 2 also show a configuration example related to the polarization element. In this example, an absorption type changing element is arranged as an optical element 16 immediately after the display surface sf1 of the LCD 12. The absorption type changing element absorbs components other than the S polarized light with respect to the first image light C1 and the second image light C2.

[0177] As a modification example of the above-described polarizing element, the display surface sf1 of the LCD 12 may be divided into a first region r1 and a second region r2 , and polarizing elements may be disposed in each region.

[0178] The structure related to IR cutoff is as follows. First, an IR absorbing function is provided in the dust cover 71. For example, an IR absorbing sheet is provided as one layer in the dust cover 71. In addition, the mirrors M21 and M22 as the concave mirrors 1301 are composed of cold mirrors.

[0179] exist Fig.13 In the figure, consider the case where external light such as sunlight passes through the dust cover 71 in the direction opposite to the direction of the image light C1 and C2 and enters the frame 60. Regarding the external light, the IR component is first cut off by the IR absorption function of the dust cover 71. Sometimes the external light is reflected by the concave mirror M1, and part of the reflected external light is further reflected by the mirror M21 and the mirror M22. At this time, the cold light mirrors serving as the mirrors M21 and the mirror M22 cut off the IR component of the incident external light. Part of the external light reflected by the mirrors M21 and the mirror M22 sometimes further goes toward the image forming unit PGU1 and enters the display surface sf1. At this time, the optical element 16 on the front surface side of the LCD 12 reflects or absorbs the external light. As a result, the external light reaching the display surface sf1 of the LCD 12 is reduced. Therefore, panel burnout of the LCD 12 can be prevented or reduced.

[0180] As a modification of the second embodiment, a configuration may be adopted in which the characteristics of the S-polarized light and the P-polarized light are reversed in the first image light C1 and the second image light C2 from the image forming unit PGU1 .

[0181] [Effects of Embodiment 2, etc.]

[0182] As described above, according to the HUD device 1 of the second embodiment, in addition to the effects of being able to appropriately form the two display areas 5 ( 51 , 52 ) similar to the first embodiment, the image display unit 200 can be further miniaturized.

[0183] [Regarding the relationship between the effective area of ​​the concave mirror and the display area]

[0184] In the first embodiment and the like, various structures can be realized regarding the relationship between the effective area illuminated by the two image lights C1 and C2 on the reflection surface sf5 of the concave mirror M1 and the formation positions of the two display areas 5 (51, 52), so the following is a supplementary explanation. Figure 5 , Figure 6 Two structural examples are shown in FIG, but the present invention is not limited thereto. Fig.18 , Fig.19 A modified example is shown in FIG. Fig.18 For the third structural example, Fig.19 This is the fourth structural example.

[0185] exist Fig.18 In the third structural example, in the concave mirror M1, two effective areas of the two image lights C1 and C2 are separated and formed into areas 401 and 402. In contrast, according to the detailed design of the optical system, two display areas 5 (51, 52) are formed in an overlapping manner when observed from the viewpoint 6. As the detailed design of the optical system, the position and orientation of the image forming unit, the shape of each mirror M21, M22, M1, the direction of reflection of each image light, etc. can be listed.

[0186] exist Fig.19 In the fourth structural example, in the concave mirror M1, two effective areas of the two image lights C1 and C2 are formed in an overlapping manner as areas 401 and 402. In contrast, according to the detailed design of the optical system, when observed from the viewpoint 6, two display areas 5 (51, 52) are formed separately.

[0187] The present invention has been specifically described above based on the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist. In addition to the necessary components, each embodiment can add, delete, replace, etc. the components. In the absence of special limitations, each component can be one or more. It can also be a combination of the embodiments.

[0188] When the technology involved in the implementation method is used, as described above, the effective area of ​​the display panel corresponding to the image light from the light source device is divided into the first area and the second area, and the first image light from the first area is used to form a virtual image of the first display area, and the second image light from the second area is used to form a virtual image of the second display area. By providing a technology that can form two virtual images corresponding to the two display areas in front of the windshield when observed from the driver's point of view, it is possible to provide the driver with various virtual images for driving assistance, etc., and provide an information display device (head-up display device) that contributes to safe driving, etc. As a result, traffic accidents can be prevented. In addition, it is possible to contribute to "3. Health and well-being for all" of the Sustainable Development Goals (SDGs) proposed by the United Nations.

[0189] Explanation of symbols

[0190] 1: HUD device; 2: vehicle; 3: windshield; 4: vehicle information; 5, 51, 52: display area (display zone); 6: viewpoint; 7: opening; 8: steering wheel; 9, V1, V2: virtual image; 10: image display device; 15: optical element; 60: frame; 71: dust cover; 200: image display unit or image display section; PGU1: image forming unit or image forming section; M1, M21, M22: mirror; C1, C2: image light; r1: first area; r2: second area.

Claims

1. A head-up display device, comprising: An image forming unit that emits image light; an optical element provided in the image forming section and configured to generate, as the image light, image light divided into two parts, namely, a first image light and a second image light; a first folding mirror, reflecting the first image light; a second folding mirror, reflecting the second image light; and an image projection unit that reflects the first image light from the first folding mirror and the second image light from the second folding mirror, forming a first display region as a first display area capable of displaying a first virtual image based on the first image light from the image projection unit, Based on the second image light from the image projection unit, a second display region is formed as a second display area capable of displaying a second virtual image.

2. The head-up display device according to claim 1, wherein: The image forming unit includes: a light source device; and a display panel, which generates the image light based on the light source light from the light source device. The optical element is arranged on the back side or the front side of the display panel corresponding to the second area of ​​the display surface of the display panel divided into a first area and a second area. The first image light is emitted from the first region, and the second image light is emitted from the second region.

3. The head-up display device according to claim 1, wherein: The first display area and the second display area are formed so as to be separated from or overlapped in a vertical direction in front of the transmissive member when viewed from a viewpoint of a driver of the vehicle.

4. The head-up display device according to claim 1, wherein: The first display area and the second display area are formed so that the first display area is arranged relatively far from the second display area in the front-rear direction in front of the transmissive member when viewed from the viewpoint of the driver of the vehicle.

5. The head-up display device according to claim 1, wherein: The image projection unit is formed of a mirror, and on a reflection surface, a region irradiated with the first image light and a region irradiated with the second image light are separated from or overlapped.

6. The head-up display device according to claim 1, wherein: The image projection unit is composed of a mirror and has a driving mechanism that rotates around a rotation axis extending in the horizontal direction. In a protection mode relative to a normal display mode, the mirror is rotated, and when external light is incident on the mirror in a direction opposite to the direction of the image light, the direction of the external light from the mirror to the first returning mirror and the second returning mirror is changed in a manner to prevent the external light reflected by the mirror from being incident on the display surface of the image forming unit.

7. The head-up display device according to claim 6, wherein: The head-up display device includes a sunlight sensor or a temperature sensor. When the incidence of the external light is detected based on the detection information of the sunlight sensor or the temperature sensor, the normal display mode is switched to the protection mode.

8. The head-up display device according to claim 1, wherein: The first folding mirror is composed of a concave mirror. The second folding mirror is composed of a plane mirror. The first image light is reflected by the concave mirror, forms an image at a predetermined image forming position, and then enters the image projection unit.

9. The head-up display device according to claim 1, wherein: The image forming unit includes a light source device and a display panel that generates the image light based on light from the light source device. A reflective polarization element or an absorption-type changing element is arranged on the front surface side of the display panel of the image forming section.

Images