Virtual image display device

Abstract

The invention relates to a virtual image display apparatus. An HUD (100) is a virtual image display device used in a vehicle (Am), and displays a virtual image (Vi) superimposed on a foreground. An HUD (100) is provided with: a displacement mechanism (63) that displaces the position of a display region (VA) in which a virtual image (Vi) is displayed in the vertical direction (US) of a vehicle (Am); and a head-up ECU (70) that controls the position of the display area (VA) on the basis of the content of the subject displayed as the virtual image (Vi). A head-up ECU (70) detects at least the fixation of the display region (VA) as an abnormality in the displacement of the display region (VA). When the head-up ECU (70) detects that the display area (VA) is fixed, the head-up ECU (70) performs fail-safe control of the content corresponding to the position at which the display area (VA) is fixed.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on Japanese Patent Application No. 2022-097584 filed in Japan on June 16, 2022, and Japanese Patent Application No. 2022-199678 filed in Japan on December 14, 2022, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The disclosure in this specification relates to a virtual image display device that displays a virtual image. Background Art

[0004] Patent Document 1 discloses a head-up display device that reflects an image displayed on an image display device through a reflector and projects the image onto a vehicle windshield, thereby allowing the driver to visually recognize the projected image. When an abnormality occurs in the head-up display device, the display of a virtual image is controlled so as not to hinder driving.

[0005] Patent Document 1: Japanese Patent No. 6953539

[0006] In recent years, a virtual image display device has been conceived in which the position of a display area displaying a virtual image is displaced in the up-down direction according to the content of the virtual image display. In such a virtual image display device, an abnormality may occur in a displacement mechanism that displaces the display area. However, there is no disclosure in Patent Document 1 regarding control in the case where an abnormality occurs in the displacement mechanism. As a result, there is a concern that the abnormality may have an excessive impact on the user. Summary of the invention

[0007] An object of the present disclosure is to provide a virtual image display device capable of suppressing the influence on a user caused by the occurrence of abnormality even if the display region of the virtual image is displaced.

[0008] In order to achieve the above-mentioned purpose, a disclosed method is set as a virtual image display device, which is used in a vehicle and displays a virtual image overlapped on the foreground, wherein it has: a displacement mechanism that displaces the position of a display area for displaying the virtual image along the up and down direction of the vehicle; a display control unit that controls the position of the display area according to the content that is the subject of the virtual image display; and an abnormality detection unit that at least detects the fixation of the display area as an abnormality in the displacement of the display area, and when the fixation of the display area is detected by the abnormality detection unit, the display control unit performs fail-safe control of the content corresponding to the fixed position of the display area.

[0009] In this method, when the fixation of the display area is detected as an abnormality in the displacement of the display area, fail-safe control of the content corresponding to the position where the display area is fixed is performed. Therefore, even if the virtual image display device is configured to displace the display area of ​​the virtual image, the influence on the user caused by the occurrence of the abnormality can be suppressed.

[0010] In addition, the reference numbers in brackets in the claims are only an example of the correspondence relationship with the specific structures in the embodiments described later, and do not limit the technical scope in any way. In addition, as long as there is no particular hindrance in the combination, claims that are not explicitly stated in the claims can also be combined with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a diagram for explaining a virtual image display function of a head-up display according to one embodiment of the present disclosure.

[0012] Figure 2 is a block diagram showing the electrical structure of a display system.

[0013] Figure 3 This is a diagram showing the positional relationship between the normal position and the upper position of the display area.

[0014] Figure 4 This is a diagram showing an example of a subject displayed as a virtual image at a normal position and an upper position.

[0015] Figure 5 This is a flowchart showing the details of the fail-safe transfer process performed by the head-up display ECU.

[0016] Figure 6 This is a diagram for explaining the details of fail-safe control in abnormality type 1.

[0017] Figure 7 This is a time chart showing an example of the predetermined timing.

[0018] Figure 8 This is a diagram for explaining the details of fail-safe control in abnormality type 2.

[0019] Fig. 9 This is a diagram for explaining the details of fail-safe control in abnormality type 3.

[0020] Fig.10 This is a diagram for explaining the details of fail-safe control in abnormality type 4.

[0021] Fig.11 This is a diagram for explaining the details of fail-safe control in abnormality type 5.

[0022] Fig.12 This is a diagram for explaining the details of fail-safe control in abnormality type 6. DETAILED DESCRIPTION

[0023] Figure 1 as well as Figure 2 A head-up display (hereinafter, HUD) 100 of one embodiment of the present disclosure shown is a virtual image display device that displays a virtual image Vi. The HUD 100, together with the meter display device 30 and the like, constitute a display system 110. The display system 110 is used in the vehicle Am, and cooperates with the virtual image display by the HUD 100 and the screen display by the meter display device 30 to present various information related to the vehicle Am to the driver.

[0024] The instrument display device 30 and the HUD 100 are connected to the communication bus of the vehicle network installed in the vehicle Am so as to be able to communicate. The communication bus of the vehicle network is also connected to other vehicle ECUs such as the navigation ECU (Electronic Control Unit) 21 and the driving assistance ECU 22. These structures connected to the communication bus as nodes can communicate with each other. Specific nodes in these ECUs can also be directly electrically connected to each other and can communicate without going through the communication bus.

[0025] The meter display device 30 is one of the multiple display devices mounted on the vehicle Am, and presents information to the driver by displaying an image on the display screen. The meter display device 30 is a structure equivalent to a combination meter, and is housed in the instrument panel 9 with the display screen facing the driver's seat. The meter display device 30 includes a meter display 31 and a meter ECU 32.

[0026] The meter display 31 is, for example, a liquid crystal display or an organic EL display, etc. The meter display 31 displays a speedometer image, a tachometer image, a navigation map image, a driving assistance image, etc. on a display screen based on image data acquired from the meter ECU 32 .

[0027] The instrument ECU 32 is an electronic control unit that manages the user interface functions of the vehicle Am. The instrument ECU 32 comprehensively controls the display performed by the instrument display 31, the HUD 100, and the center display and other display devices. The instrument ECU 32 is a structure that includes a computer with a processing unit, RAM, storage, input and output interfaces, and a bus connecting them as a main body. The instrument ECU 32 generates image data provided to the instrument display 31 based on various information output to the communication bus. The instrument ECU 32 cooperates with the head-up ECU 70 described later and performs calculation processing for virtual image display. The instrument ECU 32 generates image data for displaying the virtual image Vi and outputs the generated image data to the HUD 100 in sequence.

[0028] The HUD 100 is one of the multiple display devices mounted on the vehicle Am, and presents information to the driver through a virtual image Vi formed in the space in front of the driver. The HUD 100 is accommodated in a storage space provided inside the instrument panel 9. The HUD 100 projects the light formed as the virtual image Vi (hereinafter, the display light Lvi) toward the projection range PA of the windshield WS. The display light Lvi projected onto the windshield WS is reflected to the driver's seat side in the projection range PA and is perceived by the driver. The driver visually confirms that the display of the virtual image Vi is superimposed on the foreground seen through the projection range PA.

[0029] The HUD 100 includes a PGU (Picture Generation Unit) 61 , a magnifying optical system 62 , a displacement mechanism 63 , a position sensor 64 , and a head-up ECU 70 .

[0030] The PGU 61 has an LCD (Liquid Crystal Display) panel and a backlight. The PGU 61 is fixed to the housing of the HUD 100 in a posture that the display surface of the LCD panel faces the magnifying optical system 62 (a plane mirror described later). The PGU 61 displays each frame image of the image data on the display surface of the LCD panel, and transmits the display surface through the backlight to emit the display light Lvi formed as a virtual image Vi toward the magnifying optical system 62.

[0031] The magnifying optical system 62 is a structure including at least a plane mirror formed by vapor-depositing a metal such as aluminum on the surface of a base material made of synthetic resin or glass, and a concave mirror 62a. The plane mirror reflects the display light Lvi emitted from the PGU 61 toward the concave mirror 62a. The concave mirror 62a expands the display light Lvi incident from the plane mirror by reflection and projects it to the projection range PA above.

[0032] The displacement mechanism 63 is a mechanism that mechanically moves the area of ​​the windshield WS that becomes the projection range PA. The projection range PA is the range for the display light Lvi to be projected, and is the range in which the virtual image Vi is displayed visually by the driver. The displacement mechanism 63 is composed of an actuator 63a and a gear unit, etc. The displacement mechanism 63 works by transmitting the driving force of the actuator 63a to the housing of the concave mirror 62a via the gear unit, thereby rotating the concave mirror 62a around the rotation axis specified along the left-right direction Yo. The displacement mechanism 63 increases or decreases the inclination angle of the concave mirror 62a, thereby changing the emission direction of the display light Lvi from the concave mirror 62a toward the windshield WS. By changing the posture of the concave mirror 62a in this way, the projection range PA of the display light Lvi and the position of the display area VA visually confirmed by the driver are moved at least in the up-down direction US.

[0033] If further described in detail, when a virtual range in a space where the virtual image Vi can be imaged is defined as an imaging surface IS, the display area VA is defined based on a virtual line connecting the driver's viewpoint EP and the outer edge of the imaging surface IS. The display area VA is a viewing angle range for displaying the virtual image Vi when viewed from the viewpoint EP. In the HUD 100, the horizontal viewing angle in the horizontal direction (for example, about 6°) is larger than the vertical viewing angle in the vertical direction (for example, about 2°).

[0034] The displacement mechanism 63 displaces the position of the display area VA along the up-down direction US of the vehicle Am, and moves the front range overlapping the display area VA along the front-back direction ZG. As an example, when the displacement mechanism 63 positions the display area VA at the bottom (for example, at a depression angle of about 4°), the front range of 10 to 20 meters becomes the range within the display area VA. On the other hand, when the displacement mechanism 63 positions the display area VA at the top (for example, at a depression angle of about 2°), the front range of about 20 to 60 meters becomes the range within the display area VA.

[0035] Here, the front-rear direction ZG and the left-right direction Yo are defined with reference to the vehicle Am at rest on the horizontal plane. Specifically, the front-rear direction ZG is defined along the long side direction (travel direction) of the vehicle Am. In addition, the left-right direction Yo is defined along the width direction of the vehicle Am. Furthermore, the up-down direction US is defined along the vertical direction of the horizontal plane defining the front-rear direction ZG and the left-right direction Yo. In addition, in order to simplify the description, the description of the reference numerals representing each direction may be appropriately omitted.

[0036] The position sensor 64 is provided integrally with the actuator 63a or the gear unit. The position sensor 64 electrically or magnetically detects the tilt angle of the concave mirror 62a adjusted by the displacement mechanism 63. The position sensor 64 sequentially outputs an output signal indicating the current tilt angle of the concave mirror 62a to the head-up ECU 70.

[0037] The head-up ECU 70 is a control circuit of the HUD 100 that comprehensively controls the PGU 61 and the actuator 63a. The head-up ECU 70 is a structure that includes a computer having a processing unit 51, a RAM 52, a storage 53, an input / output interface, and a bus that connects them as a main body. The head-up ECU 70 is also provided with a driving circuit for driving the LCD panel, the backlight, and the actuator 63a, and a detection circuit for acquiring the output signal of the position sensor 64.

[0038] The head-up ECU 70 changes the subject CT displayed as the virtual image Vi in association with the position of the display area VA (see Figure 3 as well as Figure 4 Specifically, the head-up view ECU 70 switches the position of the display area VA for displaying the virtual image Vi between a plurality of positions including the normal position VP1 and the upper position VP2 in cooperation with the displacement mechanism 63 through the driving control of the actuator 63a. The head-up view ECU 70 displays the virtual image Vi associated with the normal position VP1 and the upper position VP2, respectively, according to the switching of the position of the display area VA by the actuator 63a (see Figure 4 ).

[0039] The usual position VP1 is in the driver's peripheral visual field PVF (refer to Figure 3 ) is a position of the display area VA in which the virtual image Vi is displayed. A normal position VP1 is defined below the upper position VP2. The normal position VP1 is a reference position of the display area VA and corresponds to a position that is used for a longer period than the upper position VP2. For example, the speedometer CTv (see Figure 4 In the following description, the subject CT associated with the normal position VP1 is referred to as the first subject CT1. The driver can recognize the virtual image Vi of the first subject CT1 displayed in the display area VA at the normal position VP1 when he wants to obtain information.

[0040] The upper position VP2 is to display the virtual image Vi in the center field of vision CVF (refer to Figure 3 ) in the display area VA. The upper position VP2 is set above the normal position VP1 so as not to overlap with the normal position VP1. When a specific event that should be notified to the driver occurs, the display area VA is moved from the normal position VP1 to the upper position VP2. For example, a route guidance theme CTrg (see Figure 4In the following description, the subject CT associated with the upper position VP2 is recorded as the second subject CT2. The driver can recognize the virtual image Vi of the second subject CT2 displayed in the display area VA of the upper position VP2 without significantly shifting the line of sight from the front at the timing of the event.

[0041] In addition, the relative positional relationship between the normal position VP1 and the upper position VP2 can be changed appropriately. For example, the lower edge of the upper position VP2 can be connected to the upper edge of the normal position VP1, or can be slightly separated from the upper edge of the normal position VP1. Furthermore, the display area VA of the upper position VP2 and the display area VA of the normal position VP1 can also partially overlap.

[0042] In order to realize the virtual image display control that cooperates the view position and the subject CT described above, the head-up ECU 70 includes a plurality of functional units by executing a program (virtual image display program) stored in the memory 53 by the processing unit 51. Specifically, the head-up ECU 70 includes functional units such as an information acquisition unit 71, a display control unit 72, and an abnormality detection unit 73.

[0043] The information acquisition unit 71 is connected to the communication bus and the meter ECU 32. The information acquisition unit 71 acquires from the communication bus the route information provided by the navigation ECU 21, and the object information and control state information around the vehicle provided by the driving assistance ECU 22. The image data for virtual image display generated by the meter ECU 32 is sequentially input to the information acquisition unit 71.

[0044] The information acquisition unit 71 is electrically connected to the operation unit 68. The operation unit 68 is a switch for the driver to adjust the position of the display area VA and switch the display of the virtual image Vi on and off. As the operation unit 68, a dedicated switch provided on the instrument panel 9, a steering switch provided on the steering wheel, a center display having a touch panel function, and a voice input device for detecting the driver's voice can be used.

[0045] The information acquisition unit 71 acquires input information to the operation unit 68 when the operation unit 68 is operated by the driver or the like. The input information is provided from the information acquisition unit 71 to the display control unit 72, and the position adjustment of the display area VA and the on / off switching of the virtual image display corresponding to the driver's operation are implemented. The position adjustment of the display area VA is equivalent to the user calibration used to make the position of the display area VA suitable for each driver. The user calibration is implemented when each driver first uses the HUD 100 (vehicle Am). In the user calibration, the driver operates the operation unit 68 to adjust the normal position VP1 and the upper position VP2 so that the virtual image Vi will not be invisible even if the viewpoint EP is slightly moved in the up-down direction US, the left-right direction Yo, and the front-back direction ZG. Through such user calibration, the set value of the position of the display area VA associated with each driver is stored in the memory 53.

[0046] The display control unit 72 is a control unit that comprehensively controls the PGU 61 and the actuator 63a. The display control unit 72 generates image data and control signals to be output to the PGU 61, and drive signals to be output to the actuator 63a. The display control unit 72 selects a subject CT to be displayed as a virtual image Vi, and controls the position of the display area VA according to the displayed subject CT.

[0047] The display control unit 72 selects the subject CT and the position of the display area VA for virtual image display by referring to a preset data table based on the information acquired by the information acquisition unit 71. The display control unit 72 extracts the material data of the image used to generate the image data from the RAM 52 or the storage 53 based on the selection result of the subject CT. The display control unit 72 appropriately combines the image data generated from the material data and the image data provided by the meter ECU 32 to generate each frame image of the image data. The display control unit 72 sequentially inputs the image data composed of a plurality of continuous frame images to the PGU 61.

[0048] When the display control unit 72 determines to move the display area VA, it switches the content of the subject CT of the virtual image display in association with the start or end of the drive of the actuator 63a. As an example, when the display control unit 72 moves the display area VA from the normal position VP1 to the upper position VP2, the display control unit 72 switches the content CT of the virtual image display just before the start of the movement of the display area VA. On the contrary, when the display area VA is moved from the upper position VP2 to the normal position VP1, the display control unit 72 switches the content CT of the virtual image display immediately after the movement of the display area VA is completed. In addition, in the above-mentioned user calibration, the display control unit 72 displays the virtual images Vi representing the positions of the four corners, four sides, and the center of the display area VA as the subject CT for position adjustment.

[0049] The abnormality detection unit 73 is connected to the PGU61, the actuator 63a, and the position sensor 64, and detects various abnormalities generated in the HUD 100, such as abnormal displacement of the display area VA and abnormal image. Specifically, in addition to being able to detect abnormalities in the PGU 61, abnormalities in the actuator 63a, and malfunctioning of the gear unit, the abnormality detection unit 73 can also detect circuit abnormalities in the head-up ECU 70 and software abnormalities in the virtual image display program. When the detection of an abnormality of the same content continues for multiple times (for example, about three times), the abnormality detection unit 73 determines that the abnormality has occurred. When the abnormality detection unit 73 detects an abnormality in the HUD 100 and makes an abnormality determination, it provides information indicating abnormality detection (hereinafter, abnormality detection information) and information indicating the type of abnormality detected (hereinafter, abnormality type information) to the display control unit 72.

[0050] When an abnormality occurs in the virtual image display based on the HUD 100, the display control unit 72 implements a fail-safe control so as not to hinder the normal driving of the driver. The display control unit 72 starts the fail-safe transfer process based on the abnormality detection information obtained from the abnormality detection unit 73 (see Figure 5 The display control unit 72 obtains the abnormality type information attached to the abnormality detection information (S11), and grasps the type of abnormality described later based on the abnormality type information (S12). The display control unit 72 selects the abnormality response previously associated with the grasped abnormality type (S13), and starts the fail-safe control to be implemented by transitioning to the fail-safe mode (S14). Figure 6 to Figure 12 , refer to Figure 1 as well as Figure 2 The details of the fail-safe control for each abnormality type performed by the display control unit 72 will be described.

[0051] <Abnormal type 1: Excessive rise in display area VA>

[0052] As an abnormality in the displacement of the display area VA, the abnormality detection unit 73 detects the following Figure 6 The abnormality detection unit 73 refers to the output signal of the position sensor 64, compares the current position with the position that should be at, and determines that the abnormality of excessive rise (refer to the arrow) is detected when the difference (refer to the arrow) exceeds the threshold value for multiple times (for example, three times) continuously. Figure 7Abnormality occurs). The phenomenon of excessive rise of the display area VA is caused by the repeated displacement in the up-down direction US during driving, and the inclination angle of the concave mirror 62a is offset from the normal position due to vibration, etc. In the case of excessive rise of the display area VA, it is possible that the subject CT whose virtual image is displayed at the upper position VP2H is located in the center field of view CVF and blocks the driver's forward field of view, thereby hindering normal driving. When the abnormality detection unit 73 detects excessive rise of the display area VA, in addition to the abnormality detection information, it also provides the display control unit 72 with abnormality type information indicating that the display area VA has risen excessively.

[0053] Even when the abnormality detection unit 73 detects that the display area VA has risen excessively, the display control unit 72 continues to display the virtual image Vi. When the abnormality detection unit 73 detects that the display area VA has risen excessively, the display control unit 72 may continue to display the area VA in a state where it can be displaced, or may limit (prohibit) the displacement of the display area VA. As a fail-safe control, the display control unit 72 performs a restoration process on the displacement mechanism 63 at a predetermined timing. The predetermined timing may be, for example, the next start of the HUD 100, specifically, the timing when the state of the ignition switch of the vehicle Am is switched from the off state to the on state, etc. (see Figure 7 In addition, the on state of the ignition switch of the vehicle Am indicates a state in which the vehicle Am can travel by shifting to a forward gear.

[0054] In the restoration process, the display control unit 72 refers to the output signal of the position sensor 64 and performs drive control of the actuator 63a to reset the reference position (zero point) of the inclination angle of the concave mirror 62a (refer to Figure 7 ZPD). After resetting the reference position, the display control unit 72 reads the value set in the user calibration, thereby restoring the display area VA to the normal position again. In addition, the display control unit 72 performs the reset of the reference position based on the switching of the "enable" of the HUD 100 to the off state regardless of whether an abnormality occurs or not, in other words, in both normal and abnormal situations (see Figure 7 The display control unit 72 can return the display area VA to the normal position at an earlier timing than in a normal state by performing the reset of the reference position based on the on-off switching of the ignition switch power source as the restoration process only in an abnormal state.

[0055] After determining that the display area VA has abnormally risen excessively, the display control unit 72 may continue to displace the display area VA and display the virtual image Vi. In this case, the display control unit 72 maintains a state in which the position of the display area VA can be changed by an operation input to the operation unit 68 until the HUD 100 becomes disconnected. That is, as a fail-safe control, the display control unit 72 performs a restoration process at a predetermined timing on the basis of setting the state in which the position of the display area VA can be changed. Even if the driver performs a position adjustment to return the display area VA that has risen excessively, the display control unit 72 restores the position of the display area VA to the initial value set by the initial user calibration through the above-mentioned restoration process.

[0056] According to the above fail-safe control, the driver can adjust the upper position VP2H and the normal position VP1H that have been excessively raised to a suitable position by inputting the operation of the operation unit 68 during the temporary parking of the vehicle Am. In addition, according to the restoration process at the next start, the virtual image Vi is not invisible, and the up-and-down movement of the display area VA in the normal movable range is restarted. In addition, when the restoration process is implemented, the adjustment result of the viewing angle position implemented after the detection of excessive rise can be abandoned.

[0057] <Abnormal type 2: Fixation of display area VA in upper position VP2>

[0058] As an abnormality in the displacement of the display area VA, the abnormality detection unit 73 detects the fixation of the display area VA. The abnormality detection unit 73 determines that fixation has occurred when the inclination angle of the concave mirror 62a, that is, the output signal of the position sensor 64 does not change despite the actuator 63a being driven. The fixation of the display area VA may occur due to malfunction of the actuator 63a, malfunction of the gear unit, malfunction of the control circuit or software, etc. When the abnormality detection unit 73 detects the fixation of the display area VA, it further determines the position where the fixation has occurred by referring to the output signal of the position sensor 64. When the abnormality detection unit 73 detects the fixation of the display area VA, in addition to the abnormality detection information, it also provides the display control unit 72 with abnormality type information indicating that the fixation has occurred and the position where it has occurred.

[0059] like Figure 8As shown, when the display area VA is fixed at the upper position VP2, the first subject CT1 that should be displayed at the normal position VP1 is displayed inside or near the center visual field CVF. In many cases, the first subject CT1 displayed at the normal position VP1 is a display that moves faster or contains more information. Therefore, if the display area VA is not lowered and the first subject CT1 is displayed in the display area VA at the upper position VP2, the driver's forward field of vision may be blocked, thereby hindering normal driving.

[0060] When the display area VA is fixed at the upper position VP2, the display control unit 72 starts abnormal response based on fail-safe control earlier than when the display area VA is fixed at the normal position VP1. Specifically, when the display area VA is fixed at the upper position VP2, the display control unit 72 determines whether the subject CT being displayed obstructs the driver's field of vision. The display control unit 72 estimates whether there is a phenomenon such as flickering based on the display size of the subject CT being displayed, the rate of display change, the display position within the viewing angle, etc. The display control unit 72 may also estimate that there is a phenomenon such as flickering when displaying a predetermined specific subject CT, or may grasp the display state of the subject CT being displayed and estimate whether there is a phenomenon such as flickering. When the display control unit 72 estimates that there is a phenomenon such as flickering, it determines that the subject CT being displayed obstructs the field of vision.

[0061] If the display control unit 72 determines that the subject CT being displayed obstructs the field of view, it does not perform the above-mentioned restoration process and continues to display the second subject CT2 (see Figure 4 ) and stops displaying the first subject CT1. The above prevents, for example, the flickering of the virtual image Vi caused by the change of the numbers in the speedometer CTv. After stopping displaying the virtual image Vi of the first subject CT1, the display control unit 72 turns on the virtual image Vi at a predetermined timing (see reference) such as the next time the ignition switch of the vehicle Am is turned from the off state to the on state. Figure 7 IG ON), the displacement mechanism 63 is reset. Even in the case of a type 2 fixed abnormality, the display control unit 72 performs a reset as a reference position for the restoration process based on the on-switching of the ignition switch state only when the abnormality occurs (see Figure 7 When the fixation is eliminated by the restoration process, the display control unit 72 resumes the display of the first subject CT1. On the other hand, when the fixation is not eliminated by the restoration process, the display control unit 72 continues the state in which the display of the first subject CT1 was suspended.

[0062] When the display control unit 72 determines that the subject CT being displayed does not obstruct the field of view, the display control unit 72 immediately starts the above-mentioned restoration process as a fail-safe control. When the fixation is eliminated by the restoration process, the display control unit 72 restarts the display of the virtual image Vi. On the other hand, when the fixation is not eliminated by the restoration process, the display control unit 72 continues the display of the second subject CT2 and stops the display of the first subject CT1.

[0063] <Abnormal type 3: Fixation of display area VA in the middle position>

[0064] like Fig. 9 As shown, when the display area VA is not completely transferred but fixed between the normal position VP1 and the upper position VP2 (hereinafter referred to as the middle position VPM), the first subject CT1 such as the speedometer CTv is also displayed near the center field of view CVF. In this case, as in the case of being fixed at the upper position VP2, the driver's forward field of view may be blocked, thereby hindering normal driving.

[0065] When the abnormality detection unit 73 detects fixation in the middle position VPM, the display control unit 72 implements the same fail-safe control as when fixation in the upper position VP2 is detected. Specifically, the display control unit 72 determines whether the subject CT being displayed obstructs the driver's field of vision. If it is determined that the subject CT being displayed obstructs the driver's field of vision, the display control unit 72 continues to display the second subject CT2 (see FIG. Figure 4 ) and suspends the display of the first subject CT1. After suspending the display of the first subject CT1, the display control unit 72 displays the first subject CT1 at a predetermined timing (see reference) such as the next time the ignition switch of the vehicle Am is turned from the off state to the on state. Figure 7 Even in the case of a fixed abnormality of type 3, the display control unit 72 performs the reset as the reference position of the restoration process based on the on-switching of the ignition switch state only when the abnormality occurs (refer to Figure 7 On the other hand, when it is determined that the subject CT being displayed does not obstruct the field of view, the display control unit 72 immediately starts the above-mentioned restoration process as a fail-safe control.

[0066] <Abnormal type 4: Unsmooth displacement>

[0067] As an abnormality in the displacement of the display area VA, the abnormality detection unit 73 detects the following Fig.10 Normally, the movement of the display area VA between the normal position VP1 and the upper position VP2 is performed at a substantially constant speed (see Fig.10On the other hand, if some abnormality occurs in the actuator 63a, the drive circuit, or the gear unit, the moving speed of the display area VA changes (see Fig.10 The abnormality detection unit 73 refers to the output signal of the position sensor 64 and determines that the displacement is not smooth when the change in the moving speed exceeds the threshold value.

[0068] Even when the abnormality detection unit 73 detects and determines that the displacement is not smooth, the display control unit 72 continues to display the virtual image Vi. In this case, although the lack of smoothness causes trouble to the driver, the display position of the subject CT is the same as in normal times and is unlikely to become a position that obstructs the driver's forward field of view. Therefore, the display control unit 72 gives priority to the convenience of the driver and continues to display information based on the virtual image Vi. As a fail-safe control, the display control unit 72 will display the virtual image Vi at a predetermined timing (see reference) such as the next time the ignition switch of the vehicle Am is turned on. Figure 7 Even in the case of a type 4 non-smooth abnormality, the display control unit 72 performs the reset as the reference position for the restoration process based on the on-switching of the ignition switch state only when the abnormality occurs (see Figure 7 Even when the unevenness is not eliminated by the restoration process, the display control unit 72 continues to display the virtual image Vi.

[0069] <Abnormal type 5: Fixed display area VA in normal position VP1>

[0070] As an abnormality in the displacement of the display area VA, the abnormality detection unit 73 detects the following Fig.11 The display area VA is fixed in the normal position VP1 as shown. When the display area VA is fixed in the normal position VP1, the second subject CT2 that should be displayed in the upper position VP2 is displayed in the normal position VP1. In this case, the second subject CT2 is only displayed at a lower position than normal, and it is unlikely to become a display object that obstructs the driver's forward field of vision. Therefore, the display control unit 72 continues to display the virtual image Vi when the display area VA is fixed in the normal position VP1. As a fail-safe control, the display control unit 72 turns off the ignition switch of the vehicle Am at a predetermined timing (refer to Figure 7 Even in the case of a fixed abnormality of type 5, the display control unit 72 performs the reset as the reference position of the restoration process based on the on-switching of the ignition switch state only when the abnormality occurs (refer to Figure 7 Even if the fixation is not eliminated by the restoration process, the display control unit 72 continues to display the virtual image Vi.

[0071] <Abnormal type 6: Excessive decrease in display area VA>

[0072] As an abnormality in the displacement of the display area VA, the abnormality detection unit 73 detects the following Fig.12 The abnormality detection unit 73 refers to the output signal of the position sensor 64, compares the current position with the position that should be located, and determines that it is an abnormality of excessive descent when the difference between them (see arrow) exceeds the threshold. The phenomenon of excessive descent of the display area VA is similar to the abnormality of excessive rise mentioned above, which is caused by the repeated displacement of the display area VA during driving, and the inclination angle of the concave mirror 62a is deviated from the normal position.

[0073] When the display area VA has been excessively lowered, although the display positions of the first subject CT1 and the second subject CT2 are farther away from the center field of view CVF than in normal times, there is no situation where the forward field of view is blocked. Therefore, even when the display control unit 72 detects that the display area VA has been excessively lowered, the display control unit 72 continues to display the virtual image Vi. When the display control unit 72 detects that the display area VA has been excessively lowered, the display control unit 72 may continue to display the state in which the display area VA can be displaced, or may limit (prohibit) the displacement of the display area VA. As a fail-safe control, the display control unit 72 may limit (prohibit) the displacement of the display area VA at a specified timing such as the next time the ignition switch of the vehicle Am is turned from the off state to the on state. Figure 7 Even in the case of a type 6 excessive descent abnormality, the display control unit 72 performs a reset as a reference position for the restoration process based on the on-switching of the ignition switch state only when the abnormality occurs (see Figure 7 Abnormal ZPD).

[0074] After determining that the display area VA has dropped excessively abnormally, the display control unit 72 may continue to displace the display area VA and display the virtual image Vi. In this case, the display control unit 72 maintains a state in which the position of the display area VA can be changed by an operation input to the operation unit 68 until the HUD 100 is turned off. That is, as a fail-safe control, the display control unit 72 performs a restoration process at a predetermined timing on the basis of setting the state in which the position of the display area VA can be changed. Even if the driver performs a position adjustment to return the display area VA that has dropped excessively, the display control unit 72 restores the position of the display area VA to the initial value set by the initial user calibration through the above-mentioned restoration process.

[0075] According to the above fail-safe control, the driver can adjust the upper position VP2L and the normal position VP1L that have been excessively lowered to an appropriate position by inputting the operation of the operation unit 68, for example, during the temporary parking of the vehicle Am. In addition, according to the restoration process at the next start, the virtual image Vi does not become invisible, and the vertical movement of the display area VA in the normal movable range is restarted.

[0076] <Abnormality type 7: Display area VA continues to shake up and down>

[0077] As an abnormality in the displacement of the display area VA, the abnormality detection unit 73 detects an abnormality in which the display area VA is not fixed at a specific position but continuously shakes (continuously moves) in the up-down direction US. For example, when an abnormality occurs in the actuator 63a, the drive circuit, or the gear unit, the display area VA becomes smaller and continuously moves in the up-down direction US. In other words, the position of the display area VA is unstable. The abnormality detection unit 73 refers to the output signal of the position sensor 64, and when a continuous change exceeding a threshold value is observed in the position of the display area VA, it is determined that the display area VA is continuously shaking up and down.

[0078] When the abnormality detection unit 73 detects that the display area VA is continuously shaking, the display control unit 72 determines whether the subject CT being displayed obstructs the driver's field of vision. When the display control unit 72 determines that the subject CT being displayed obstructs the driver's field of vision, it does not perform a recovery process, but immediately terminates the display of the virtual image Vi as a fail-safe control. This avoids a situation in which the driver loses attention to the surroundings due to the continuous movement of the virtual image Vi in the driver's field of vision, thereby hindering normal driving. In this case, the display control unit 72 terminates the display of the virtual image Vi at a predetermined timing (see the ignition switch of the vehicle Am at the next start, for example, when the ignition switch is turned from the off state to the on state). Figure 7 Even in the case of a continuous movement abnormality of type 7, the display control unit 72 performs the reset as the reference position for the restoration process based on the on-switching of the ignition switch state only when the abnormality occurs (see Figure 7 On the other hand, when it is determined that the subject CT being displayed does not obstruct the field of view, the display control unit 72 immediately starts the above-mentioned restoration process as a fail-safe control.

[0079] <Abnormality type 8: The image does not match the movement of the actuator 63a>

[0080] As an abnormality in the displacement of the display area VA, the abnormality detection unit 73 detects an abnormality in which the timing of switching the subject CT and the timing of displacing the display area VA are offset. The abnormality detection unit 73 grasps the switching timing of the subject CT (image) based on the display control information obtained from the display control unit 72. In addition, the abnormality detection unit 73 refers to the output signal of the position sensor 64 to grasp the start timing of the view angle movement. Based on the grasped timings, the abnormality detection unit 73 detects the occurrence of phenomena such as the operation of the actuator 63a being later than the prescribed timing and the switching of the image being later than the prescribed timing.

[0081] The display control unit 72 continues to display the virtual image Vi even when the abnormality detection unit 73 detects a timing shift. In this case, although the driver may feel uncomfortable when the position of the display area VA is switched, it is unlikely that the subject CT will obstruct the forward field of vision. Therefore, by continuing to display the virtual image Vi, the convenience of the driver can be prioritized.

[0082] <Abnormality type 9: Abnormal noise and vibration accompanied by displacement>

[0083] As an abnormality of the displacement of the display area VA, it is assumed that an abnormal sound or vibration is generated along with the up and down movement of the position of the display area VA. Such an abnormality is difficult to detect by the abnormality detection unit 73. Therefore, an operating unit 68 capable of switching the display on and off is provided in the HUD 100. A driver who finds the abnormal sound and vibration annoying can input an operation to turn off the display to the operating unit 68. The display control unit 72 terminates the display of the virtual image Vi based on the input information obtained from the operating unit 68. In this way, although the abnormal sound and vibration accompanying the displacement of the display area VA may annoy the driver, it is unlikely to become a factor that hinders the field of vision ahead. Therefore, by continuing the display of the virtual image Vi, the convenience of the driver can be prioritized.

[0084] <Anomaly Type 10: White Screen>

[0085] In addition to the abnormality of the displacement of the display area VA, the abnormality detection unit 73 further detects the abnormality of the PGU61 that emits the display light Lvi. Specifically, as an abnormality of PGU61, the abnormality detection unit 73 detects an abnormality in the light directly emitted from the backlight (hereinafter referred to as white screen abnormality). The white screen abnormality occurs due to an abnormality in the LCD panel or the driving circuit. If the white screen abnormality occurs, the driver will have to look away from the front and will not be able to continue normal driving. Therefore, when the abnormality detection unit 73 detects the white screen abnormality of PGU61, the display control unit 72, as a fail-safe control, does not perform a recovery process and immediately terminates the display of the virtual image Vi. Thereby, it is avoided that the glare of the white screen makes it difficult to visually confirm the front and hinders normal driving.

[0086] <Summary of implementation methods>

[0087] In the present embodiment described so far, when the fixation of the display area VA is detected as an abnormality in the displacement of the display area VA, fail-safe control corresponding to the position where the display area VA is fixed is performed. Therefore, even if the HUD 100 has a structure that can displace the display area VA of the virtual image Vi, the influence on the user such as the driver caused by the occurrence of the abnormality can be suppressed.

[0088] If described in detail, it is possible to appropriately determine whether to continue displaying the virtual image Vi according to the position where the display area VA is fixed. As a result, the display of the virtual image Vi is stopped in a scene where the virtual image Vi is likely to obstruct the driver's field of vision, and the display of the virtual image Vi is allowed to continue in a scene where the virtual image Vi is unlikely to obstruct the driver's field of vision. Therefore, even if an abnormality occurs, the impact on the driver can be suppressed to a minimum.

[0089] In addition, in the present embodiment, the position of the display area VA is switched between a plurality of positions including at least the normal position VP1 and an upper position VP2 which is above the normal position VP1. Furthermore, when the display area VA is fixed at the upper position VP2, the abnormal response based on the fail-safe control is started earlier than when the display area VA is fixed at the normal position VP1. When the display area VA is fixed at the upper position VP2, there is a concern that the subject CT is displayed inside or near the center visual field CVF in an annoying manner. However, if the abnormal response is started early for the fixation in the upper position VP2, even if a virtual image Vi is generated to obstruct the driver's field of vision, it can be quickly eliminated.

[0090] In addition, in the present embodiment, when the display area VA is fixed at the upper position VP2, it is determined whether the subject CT being displayed obstructs the driver's field of vision. And, when the subject CT being displayed obstructs the field of vision, the display of the second subject CT2 associated with the upper position VP2 is continued, and on the other hand, the display of the first subject CT1 associated with the normal position VP1 is stopped. Based on the above, it is difficult to cause a situation where the first subject CT1, whose display changes rapidly, is displayed in the display area VA at the upper position VP2 overlapping with the center field of vision CVF, thereby obstructing the driver's field of vision. And, since the display of the subject CT associated with the upper position VP2 is continued, it is difficult to impair the convenience of the driver.

[0091] Furthermore, in the present embodiment, when the display area VA is fixed at the upper position VP2, the fail-safe control is implemented as a recovery process when the subject CT being displayed does not obstruct the field of view. By immediately implementing such a recovery process, the fixation of the display area VA can be eliminated. As a result, the virtual image display can be restarted with only a temporary interruption, so that the convenience of the driver is unlikely to be impaired.

[0092] In addition, in the present embodiment, when the display area VA is fixed at the normal position VP1, the display of the virtual image Vi is continued. Moreover, the restoration process is implemented at a predetermined timing as a fail-safe control. Even if the second subject CT2 that should be displayed at the upper position VP2 is displayed at the fixed normal position VP1, it is difficult to obstruct the driver's field of vision. Moreover, since the restoration process is implemented at a predetermined timing, the fixation of the display area VA can be eliminated. As described above, by implementing the process for continuing the display of the virtual image Vi, the influence on the driver caused by the fixation can be suppressed to a minimum.

[0093] In addition, in the present embodiment, when the display area VA is fixed at the middle position VPM between the normal position VP1 and the upper position VP2, it is determined whether the subject CT being displayed obstructs the driver's field of vision. And, when the subject CT being displayed obstructs the field of vision, the display of the second subject CT2 associated with the upper position VP2 is continued, and on the other hand, the display of the first subject CT1 associated with the normal position VP1 is terminated. According to the above, it is difficult to produce a situation where the first subject CT1 with a fast display change is displayed near the center field of vision CVF and obstructs the driver's field of vision. In addition, when the subject CT being displayed does not obstruct the field of vision, by immediately performing a restoration process, the virtual image display can be restarted with only a temporary interruption. As a result, it is difficult to impair the convenience of the driver.

[0094] Furthermore, in the present embodiment, as an abnormality of the displacement of the display area VA, the unevenness of the displacement is detected. Furthermore, when the unevenness is detected, the display of the virtual image Vi is continued. Thus, even when the displacement becomes uneven, each subject CT can be displayed at an appropriate display position, so that it is difficult to obstruct the driver's forward field of vision. Furthermore, by performing a restoration process at a predetermined timing to eliminate the unevenness, the influence on the driver caused by the occurrence of the abnormality can be suppressed.

[0095] In addition, in the present embodiment, as an abnormality in the displacement of the display area VA, an excessive rise of the display area VA is detected. Furthermore, when an excessive rise of the display area VA is detected, the display of the virtual image Vi is continued, and a restoration process is performed at a predetermined timing. By resetting the position of the display area VA in this way, the movable range of the display area VA can be returned to a normal range. As a result, even if an abnormality of excessive rise occurs, the influence on the driver can be suppressed to a minimum.

[0096] Furthermore, when the abnormality detection unit 73 detects that the display area VA has risen excessively, the display control unit 72 sets the display area VA to a state where the driver can adjust the position of the display area VA and continues to display the virtual image Vi, and performs the restoration process of the displacement mechanism 63 at a predetermined timing as a fail-safe control. Therefore, the driver can adjust the position of the display area VA that has risen excessively downward, for example, when parking the vehicle, and return it to an appropriate position. As a result, the influence of the abnormality of excessive rise on the driver can be further suppressed.

[0097] In addition, in the present embodiment, as an abnormality in the displacement of the display area VA, an excessive descent of the display area VA is detected. Moreover, when the excessive descent of the display area VA is detected, the display of the virtual image Vi is continued, and a restoration process is performed at a predetermined timing. By resetting the position of the display area VA in this way, the movable range of the display area VA can be returned to a normal range. As a result, even if an abnormality of excessive descent occurs, the influence on the driver can be suppressed to a minimum.

[0098] Furthermore, when the abnormality detection unit 73 detects that the display area VA has dropped too far, the display control unit 72 sets the display area VA to a state where the driver can adjust the position of the display area VA and continues to display the virtual image Vi, and performs a restoration process of the displacement mechanism 63 at a predetermined timing as a fail-safe control. Therefore, the driver can adjust the position of the display area VA that has dropped too far downward, for example, when parking the vehicle, and return the display area VA to an appropriate position. As a result, the influence of the abnormality of excessive drop on the driver can be further suppressed.

[0099] Furthermore, in the present embodiment, as an abnormality in the displacement of the display area VA, an abnormality in which the display area VA continues to shake in the up-down direction US is detected. Furthermore, when the continuous shaking of the display area VA is detected, it is determined whether the subject CT being displayed obstructs the driver's field of vision. When the subject CT being displayed obstructs the field of vision, the display of the virtual image Vi is immediately terminated as a fail-safe control. In addition, when the subject CT being displayed does not obstruct the field of vision, a recovery process as a fail-safe control is implemented to reset the position of the display area VA. As a result, the movable range of the display area VA can be returned to a normal range. According to the above abnormality response, even if the abnormality of continuous shaking of the display area VA occurs, the impact on the driver can be suppressed to a minimum.

[0100] In addition, in the present embodiment, as an abnormality of the displacement of the display area VA, an abnormality of the timing of switching the subject CT and the timing of causing the display area VA to be displaced is detected. Moreover, even when the timing shift is detected, the display of the virtual image Vi continues. In this way, when the image does not match the action of the actuator 63a, the driver may feel uncomfortable when the display area VA is switched, but it is difficult to cause a situation that obstructs the front field of vision. Therefore, by taking an abnormal response to continue the display of the virtual image Vi, even when an abnormality of the timing shift occurs, the influence on the driver can be suppressed.

[0101] In addition, in the present embodiment, the display of the virtual image Vi is stopped based on the input information of the operation unit 68 for switching the display of the virtual image Vi on and off. Therefore, when an abnormal sound or vibration occurs with the movement of the display area VA, the driver who feels uncomfortable can stop the display of the virtual image Vi according to his own judgment. Therefore, by preparing the operation unit 68 in advance, even if an abnormality that cannot be detected by the abnormality detection unit 73 occurs, the influence on the driver can be suppressed.

[0102] Furthermore, in the present embodiment, an abnormality of PGU61 that emits display light Lvi that is imaged as a virtual image Vi is detected. Furthermore, when an abnormality of PGU61 is detected, the display of the virtual image Vi is terminated. In the case where a white screen abnormality occurs due to a malfunction of PGU61, the driver is forced to look away from the front. Therefore, by immediately terminating the display of the virtual image Vi without performing a recovery process, the period during which the driver's normal driving is obstructed is shortened. As a result, the impact of the abnormality of PGU61 on the driver is minimized.

[0103] In the above embodiment, the normal position VP1 is equivalent to the "first position", the upper position VP2 is equivalent to the "second position", the PGU61 is equivalent to the "display unit", the information acquisition unit 71 is equivalent to the "input control unit", and the HUD100 is equivalent to the "virtual image display device".

[0104] (Other Embodiments)

[0105] As mentioned above, although one embodiment of the present disclosure has been described, the present disclosure is not limited to the above embodiment and can be applied to various embodiments and combinations within the scope not departing from the gist of the present disclosure.

[0106] The fail-safe control in the case where the abnormality of type 1 of the above embodiment (excessive rise of the display area VA) occurs can be appropriately changed. Specifically, in the modification 1 of the above embodiment, when the excessive rise of the display area VA is detected, the display control unit 72 stops all display of the virtual image Vi. In addition, the display control unit 72 of the modification 2 of the above embodiment stops the function of displacing the display area VA and fixes the position of the display area VA at the normal position VP1. The display control unit 72 displays the second subject CT2 at the normal position VP1 in addition to the first subject CT1.

[0107] The display control unit 72 of the third modification of the above embodiment automatically adjusts the upper position VP2 based on the abnormal detection of the excessive rise of the display area VA. In other words, the display control unit 72 reduces the displacement from the normal position VP1 to the upper position and sets the upper position VP2 to a lower position. In addition, the display control unit 72 of the fourth modification of the above embodiment immediately performs a restoration process based on the abnormal detection of the excessive rise of the display area VA.

[0108] The display control unit 72 of the fifth modification of the above-mentioned embodiment changes the display area VA to a pre-prepared subject CT for handling abnormalities, i.e., a subject CT that does not block the forward field of view, based on the abnormal detection of the excessive rise of the display area VA. The subject CT for handling abnormalities has characteristics such as a smaller display size, a lower display position, and a slower display change than the subject CT used in normal situations.

[0109] In the sixth modification of the above embodiment, real-time detection information of the viewpoint EP based on the driver monitor is provided to the head-up ECU 70. The display control unit 72 cooperates with the driver monitor to adjust the excessively raised upper position VP2 and the normal position VP1 according to the current position of the viewpoint EP based on the detection information.

[0110] In the seventh modification of the above-mentioned embodiment, information indicating the seat position of the driver's seat (hereinafter referred to as seat position information) is provided to the head-up ECU 70. The display control unit 72 estimates the current position of the viewpoint EP based on the seat position information, and adjusts the excessively raised upper position VP2 and the normal position VP1 according to the estimated viewpoint EP.

[0111] The fail-safe control in the case where the abnormality of type 1 or 6 of the above-mentioned embodiment (excessive rise or fall of the display area VA) occurs can be appropriately changed. Specifically, in the modification 8 of the above-mentioned embodiment, when the excessive rise or fall of the display area VA is detected, the display of the virtual image Vi is continued, and on the other hand, the position adjustment of the display area VA by the driver is restricted (prohibited). Therefore, by the emergency position adjustment accompanying the abnormality, the situation where the virtual image Vi is continued to be displayed in a state that is easy to be invisible can be avoided.

[0112] The fail-safe control in the case where the abnormality of type 2 or 3 of the above embodiment (fixation in the upper position VP2 or the middle position VPM) occurs can be appropriately changed. Specifically, in the modification 9 of the above embodiment, in order to avoid the obstruction of the visual field by the subject CT, the display control unit 72 does not perform the restoration process, but immediately stops the display of the virtual image Vi. In addition, the display control unit 72 performs the restoration process at the next startup.

[0113] In the modified examples 10 and 11 of the above-mentioned embodiment, the determination of whether the subject CT being displayed obstructs the driver's field of vision is omitted. When the display area VA is fixed at the upper position VP2 or the middle position VPM, the display control unit 72 of the modified example 10 continues the display of the second subject CT2 and stops the display of the first subject CT1 as a fail-safe control. In addition, when the display area VA is fixed at the upper position VP2 or the middle position VPM, the display control unit 72 of the modified example 11 immediately performs the restoration process as a fail-safe control.

[0114] The display control unit 72 of the modification 12 of the above embodiment changes the mode of the subject CT displayed as the virtual image Vi as a fail-safe control when the display area VA is fixed at the upper position VP2 or the middle position VPM. The display control unit 72 changes the mode to the subject CT prepared in advance for abnormal response, that is, the subject CT of the mode that does not block the forward field of view, as in the above modification 5. In the modification 12, the subject CT whose display mode is changed may be only the first subject CT1.

[0115] The fail-safe control in the case where the abnormality of type 4 (unsmooth displacement) of the above-mentioned embodiment occurs can be appropriately changed. Specifically, in the modification 13 of the above-mentioned embodiment, when the abnormality that the displacement becomes unsmooth is detected, the display control unit 72 stops all display of the virtual image Vi. In addition, the display control unit 72 of the modification 14 of the above-mentioned embodiment stops the function of displacing the display area VA and fixes the position of the display area VA at the normal position VP1. And, the display control unit 72 of the modification 15 of the above-mentioned embodiment immediately performs the restoration process.

[0116] The fail-safe control in the case where the abnormality of type 7 of the above-mentioned embodiment occurs (the display area VA continues to shake up and down) can be appropriately changed. Specifically, in the modified example 16 of the above-mentioned embodiment, even when the abnormality detection unit 73 detects the continuous shaking of the display area VA, the display control unit 72 continues to display the virtual image Vi. In the case of the abnormality of type 7, the continuously moving virtual image Vi may make the driver feel uncomfortable. However, if the structure of the abnormality of type 7 is extremely difficult to occur, the display control unit 72 can be a mode of continuing the display of the virtual image Vi.

[0117] Furthermore, in the modification 17 of the above embodiment, when the abnormality of continuous up-and-down movement is detected, the display control unit 72 stops the function of shifting the display area VA and fixes the position of the display area VA at the normal position VP1. In the modification 18 of the above embodiment, the display control unit 72 does not perform the restoration process and stops the display of the virtual image Vi.

[0118] The fail-safe control in the case where the abnormality of type 8 (mismatch of actions) of the above-mentioned embodiment occurs can be appropriately changed. Specifically, in the variation 19 of the above-mentioned embodiment, when the abnormality that the actions become mismatched is detected, the display control unit 72 stops the function of shifting the display area VA and fixes the position of the display area VA at the normal position VP1.

[0119] The fail-safe control in the case of an abnormality (white screen) of type 10 of the above-mentioned embodiment can be appropriately changed. Specifically, in the modified example 20 of the above-mentioned embodiment, even when an abnormality of PGU61 is detected by the abnormality detection unit 73, the display control unit 72 continues to display the virtual image Vi. In the case of an abnormality of type 10, the driver has to look away from the front, thereby hindering normal driving. However, if the structure is extremely difficult for the abnormality of type 10 to occur, the display control unit 72 can be a mode of continuing the display of the virtual image Vi.

[0120] The displacement mechanism 63 of the modification 21 of the above-mentioned embodiment can displace the display area VA in the left-right direction Yo in addition to the up-down direction US. Furthermore, the displacement mechanism 63 can also position the display area VA at a position different from the normal position VP1 and the upper position VP2. In addition, the displacement mechanism 63 can also displace the entire optical unit including the PGU 61 and the magnifying optical system 62 relative to the housing of the HUD 100. Furthermore, the displacement mechanism 63 can also displace the housing of the HUD 100 relative to the vehicle Am.

[0121] In the modification 22 of the above embodiment, part or all of the processing functions of the head-up ECU 70 are implemented by the meter ECU 32 or other onboard ECUs. In such a modification 22, the system including the meter ECU 32 or other onboard ECUs may also be a "virtual image display device".

[0122] In the PGU61 of the above-mentioned embodiment, an EL (Electro Luminescence) panel may be provided instead of the LCD panel and the backlight. In addition, a PGU61 using a plasma display panel, a cathode ray tube, an LED or other display instead of the EL panel may be used. Furthermore, a laser projector or a DLP (Digital Light Processing, a registered trademark) and a screen may be provided instead of the LCD panel and the backlight. In the PGU61 adopting such a structure, the display image depicted on the screen is projected onto the windshield WS through the magnifying optical system 62 and is formed as a virtual image Vi. In addition, the optical elements used in the magnifying optical system 62 are not limited to concave mirrors, and various reflectors, lenses, holographic optical elements, etc. may be appropriately changed.

[0123] The processing unit provided in the head-up ECU 70 and the instrument ECU 32 of the above-mentioned embodiment is hardware for calculation processing combined with RAM. The processing unit is a structure including at least one calculation core such as a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). For example, the processing unit can be a structure that also includes an FPGA (Field-Programmable Gate Array) and an IP core with other dedicated functions. On the other hand, the RAM can be a structure that includes a video RAM for image generation. The processing unit performs various processes for implementing the virtual image display method (display control method) disclosed in the present invention by accessing the RAM.

[0124] The storage is a structure including a non-volatile storage medium (persistent tangible computer readable medium, non-transitory tangible storage medium). Various programs (display control programs, etc.) executed by the processing unit are stored in the storage of each ECU 32, 70. Such a storage medium is not limited to a structure provided on a circuit substrate, and may be a structure provided in the form of a memory card, etc., inserted into a slot portion and electrically connected to the control circuit of each ECU 32, 70. In addition, the storage medium may also be an optical disc or a hard disk drive, etc., which is the basis for copying the program to each ECU 32, 70.

[0125] In the above-mentioned embodiment, each function provided by the head-up ECU 70 and the meter ECU 32 can also be provided by software and hardware executing the software, only software, only hardware, or a combination thereof. Furthermore, when such functions are provided by electronic circuits as hardware, each function can also be provided by a digital circuit including a large number of logic circuits, or an analog circuit.

[0126] The vehicle equipped with the above-mentioned display system is not limited to ordinary passenger cars for personal use, but may also be a rental vehicle, a passenger taxi, a carpooling vehicle, a truck, a bus, etc. In addition, the vehicle equipped with the display system may be a right-hand drive vehicle or a left-hand drive vehicle. Furthermore, the traffic environment in which the vehicle is traveling may be a traffic environment based on left-hand traffic or a traffic environment based on right-hand traffic. The display control based on the present disclosure may be appropriately optimized according to the road traffic laws of various countries and regions, the steering wheel position of the vehicle, etc.

[0127] The control unit and method described in the present disclosure may also be implemented by a special-purpose computer, which is composed of a processor programmed to execute one or more functions embodied by a computer program. Alternatively, the device and method described in the present disclosure may also be implemented by a special-purpose hardware logic circuit. Alternatively, the device and method described in the present disclosure may also be implemented by one or more special-purpose computers, which are composed of a combination of a processor that executes a computer program and one or more hardware logic circuits. In addition, the computer program may also be stored as an instruction executed by a computer in a computer-readable non-transient tangible recording medium.

[0128] (Disclosure of technical ideas)

[0129] This specification discloses multiple technical ideas recorded in the following multiple items. Some items are recorded in a multiple dependent form (a multiple dependent form) that selectively refers to the previous item in the subsequent item. In addition, some items are recorded in a multiple dependent form (a multiple dependent form referring to another multiple dependent form) that refers to other multiple dependent forms. These items recorded in multiple dependent forms define multiple technical ideas.

[0130] (Technical Thought 1)

[0131] A virtual image display device is used in a vehicle (Am) and displays a virtual image (Vi) superimposed on a foreground, wherein the device comprises:

[0132] A displacement mechanism (63) is configured to displace the position of a display area (VA) displaying the virtual image along the up-down direction of the vehicle;

[0133] A display control unit (72) controls the position of the display area according to the subject (CT) displayed as the virtual image; and

[0134] The abnormality detection unit (73) detects at least the fixation of the display area as an abnormality of the displacement of the display area.

[0135] The display control unit performs fail-safe control of content corresponding to a position where the display area is fixed, when the abnormality detection unit detects that the display area is fixed.

[0136] (Technical Thought 2)

[0137] According to the virtual image display device of technical idea 1,

[0138] The displacement mechanism switches the position of the display area between a plurality of positions including at least a first position (VP1) and a second position (VP2) above the first position.

[0139] The display control unit starts abnormality handling by the fail-safe control earlier when the display area is fixed at the second position than when the display area is fixed at the first position.

[0140] (Technical Thought 3)

[0141] According to the virtual image display device of technical idea 2,

[0142] The display control unit performs the fail-safe control of continuing display of the second theme (CTrg) associated with the second position and stopping display of the first theme (CTv) associated with the first position when the display area is fixed at the second position.

[0143] (Technical Thought 4)

[0144] According to the virtual image display device of technical idea 2,

[0145] The display control unit performs a restoration process of the displacement mechanism as the fail-safe control when the display area is fixed at the second position.

[0146] (Technical Thought 5)

[0147] According to the virtual image display device of technical idea 2,

[0148] For the display control unit,

[0149] When the display area is fixed at the second position, determining whether the subject being displayed obstructs the driver's field of vision,

[0150] In the case where the subject being displayed obstructs the field of view, the display of the second subject (CT2) associated with the second position is continued, and the display of the first subject (CT1) associated with the first position is suspended,

[0151] When the subject being displayed does not obstruct the field of view, the restoration process of the displacement mechanism is performed as the fail-safe control.

[0152] (Technical Thought 6)

[0153] According to the virtual image display device of technical idea 2,

[0154] The display control unit changes the form of the subject displayed as the virtual image as the fail-safe control when the display area is fixed at the second position.

[0155] (Technical Thought 7)

[0156] A virtual image display device according to any one of technical concepts 2 to 6, wherein:

[0157] The display control unit continues displaying the virtual image when the display area is fixed at the first position, and performs a restoration process of the displacement mechanism at a predetermined timing as the fail-safe control.

[0158] (Technical Thought 8)

[0159] A virtual image display device according to any one of technical concepts 2 to 7, wherein:

[0160] For the display control unit,

[0161] When the display area is fixed between the first position and the second position, determining whether the subject being displayed obstructs the driver's field of vision,

[0162] In the case where the subject being displayed obstructs the field of view, the display of the second subject (CT2) associated with the second position is continued, and the display of the first subject (CT1) associated with the first position is suspended,

[0163] When the subject being displayed does not obstruct the field of view, the restoration process of the displacement mechanism is performed as the fail-safe control.

[0164] (Technical Thought 9)

[0165] A virtual image display device according to any one of technical concepts 2 to 8, wherein:

[0166] The abnormality detection unit further detects unevenness of the displacement as an abnormality of the displacement of the display area.

[0167] When the abnormality detection unit detects the unevenness, the display control unit continues displaying the virtual image and performs a restoration process of the displacement mechanism at a predetermined timing as the fail-safe control.

[0168] (Technical Thought 10)

[0169] A virtual image display device according to any one of technical concepts 1 to 9, wherein:

[0170] The abnormality detection unit further detects an excessive rise of the display area as an abnormality in displacement of the display area.

[0171] The display control unit performs a restoration process of the displacement mechanism as the fail-safe control at a predetermined timing when the abnormality detection unit detects that the display area has excessively risen.

[0172] (Technical Thought 11)

[0173] A virtual image display device according to any one of technical concepts 1 to 10, wherein:

[0174] The abnormality detection unit further detects an excessive downward movement of the display area as an abnormality in the displacement of the display area.

[0175] The display control unit performs a restoration process of the displacement mechanism as the fail-safe control at a predetermined timing when the abnormality detection unit detects that the display area has excessively descended.

[0176] (Technical Thought 12)

[0177] A virtual image display device according to any one of technical concepts 1 to 11, wherein:

[0178] The abnormality detection unit further detects an abnormality in which the display area continuously shakes in the up-down direction as an abnormality in the displacement of the display area.

[0179] For the display control unit,

[0180] When the abnormality detection unit detects continuous shaking of the display area, determining whether the subject being displayed obstructs the driver's field of vision,

[0181] In the case where the subject being displayed obstructs the field of view, the display of the virtual image is stopped as the fail-safe control.

[0182] When the subject being displayed does not obstruct the field of view, the restoration process of the displacement mechanism is performed as the fail-safe control.

[0183] (Technical Thought 13)

[0184] A virtual image display device according to any one of technical concepts 1 to 11, wherein:

[0185] The abnormality detection unit further detects an abnormality in which the display area continuously shakes in the up-down direction as an abnormality in the displacement of the display area.

[0186] The display control unit continues displaying the virtual image even when the abnormality detection unit detects that the display area continues to shake.

[0187] (Technical Thought 14)

[0188] A virtual image display device according to any one of technical concepts 1 to 13, wherein:

[0189] As an abnormality in the displacement of the display area, the abnormality detection unit further detects an abnormality in which the timing of switching the theme and the timing of displacing the display area are offset.

[0190] The display control unit continues displaying the virtual image even when the abnormality detection unit detects a shift in timing.

[0191] (Technical Thought 15)

[0192] A virtual image display device according to any one of technical concepts 1 to 14, wherein:

[0193] The apparatus further comprises an input grasping unit (71) for acquiring input information to an operating unit (68) for switching on and off the display of the virtual image.

[0194] The display control unit stops displaying the virtual image based on the input information.

[0195] (Technical Thought 16)

[0196] A virtual image display device according to any one of technical concepts 1 to 15, wherein:

[0197] The abnormality detection unit further detects an abnormality of a display unit (61) that emits display light (Lvi) for forming the virtual image.

[0198] The display control unit stops display of the virtual image as the fail-safe control when the abnormality detection unit detects an abnormality in the display unit.

[0199] (Technical Thought 17)

[0200] A virtual image display device according to any one of technical concepts 1 to 15, wherein:

[0201] The abnormality detection unit further detects an abnormality of a display unit (61) that emits display light (Lvi) for forming the virtual image.

[0202] The display control unit continues displaying the virtual image even when the abnormality detection unit detects an abnormality in the display unit.

Claims

1. A virtual image display device, used in a vehicle (Am), for displaying a virtual image (Vi) superimposed on a foreground, wherein: have: A displacement mechanism (63) is configured to displace the position of a display area (VA) displaying the virtual image along an up-down direction (US) of the vehicle; A display control unit (72) controls the position of the display area according to the content of the subject (CT) displayed as the virtual image; and The abnormality detection unit (73) detects at least the fixation of the display area as an abnormality of the displacement of the display area. The display control unit performs fail-safe control of content corresponding to a position where the display area is fixed, when the abnormality detection unit detects that the display area is fixed.

2. The virtual image display device according to claim 1, wherein: The displacement mechanism switches the position of the display area between a plurality of positions including at least a first position (VP1) and a second position (VP2) above the first position. The display control unit starts abnormality handling by the fail-safe control earlier when the display area is fixed at the second position than when the display area is fixed at the first position.

3. The virtual image display device according to claim 2, wherein: The display control unit performs the fail-safe control of continuing display of the second theme (CT2) associated with the second position and stopping display of the first theme (CT1) associated with the first position when the display area is fixed at the second position.

4. The virtual image display device according to claim 2, wherein: The display control unit performs a restoration process of the displacement mechanism as the fail-safe control when the display area is fixed at the second position.

5. The virtual image display device according to claim 2, wherein: For the display control unit, When the display area is fixed at the second position, determining whether the subject being displayed obstructs the driver's field of vision, In the case where the subject being displayed obstructs the field of view, the display of the second subject (CT2) associated with the second position is continued, and the display of the first subject (CT1) associated with the first position is suspended, When the subject being displayed does not obstruct the field of view, the restoration process of the displacement mechanism is performed as the fail-safe control.

6. The virtual image display device according to claim 2, wherein: The display control unit changes the form of the subject displayed as the virtual image as the fail-safe control when the display area is fixed at the second position.

7. The virtual image display device according to any one of claims 2 to 6, wherein: The display control unit continues displaying the virtual image when the display area is fixed at the first position, and performs a restoration process of the displacement mechanism at a predetermined timing as the fail-safe control.

8. The virtual image display device according to any one of claims 2 to 6, wherein: For the display control unit, When the display area is fixed between the first position and the second position, determining whether the subject being displayed obstructs the driver's field of vision, In the case where the subject being displayed obstructs the field of view, the display of the second subject (CT2) associated with the second position is continued, and the display of the first subject (CT1) associated with the first position is suspended, When the subject being displayed does not obstruct the field of view, the restoration process of the displacement mechanism is performed as the fail-safe control.

9. The virtual image display device according to any one of claims 2 to 5, wherein: The abnormality detection unit further detects unevenness of the displacement as an abnormality of the displacement of the display area. When the abnormality detection unit detects the unevenness, the display control unit continues displaying the virtual image and performs a restoration process of the displacement mechanism at a predetermined timing as the fail-safe control.

10. The virtual image display device according to any one of claims 1 to 6, wherein: The abnormality detection unit further detects an excessive rise of the display area as an abnormality in displacement of the display area. The display control unit performs a restoration process of the displacement mechanism as the fail-safe control at a predetermined timing when the abnormality detection unit detects that the display area has excessively risen.

11. The virtual image display device according to any one of claims 1 to 6, wherein: The abnormality detection unit further detects an excessive downward movement of the display area as an abnormality in the displacement of the display area. The display control unit performs a restoration process of the displacement mechanism as the fail-safe control at a predetermined timing when the abnormality detection unit detects that the display area has excessively descended.

12. The virtual image display device according to any one of claims 1 to 6, wherein: The abnormality detection unit further detects an abnormality in which the display area continuously shakes in the up-down direction as an abnormality in the displacement of the display area. For the display control unit, When the abnormality detection unit detects continuous shaking of the display area, determining whether the subject being displayed obstructs the driver's field of vision, In the case where the subject being displayed obstructs the field of view, the display of the virtual image is stopped as the fail-safe control. When the subject being displayed does not obstruct the field of view, the restoration process of the displacement mechanism is performed as the fail-safe control.

13. The virtual image display device according to any one of claims 1 to 6, wherein: The abnormality detection unit further detects an abnormality in which the display area continuously shakes in the up-down direction as an abnormality in the displacement of the display area. The display control unit continues displaying the virtual image even when the abnormality detection unit detects that the display area continues to shake.

14. The virtual image display device according to any one of claims 1 to 6, wherein: As an abnormality in the displacement of the display area, the abnormality detection unit further detects an abnormality in which the timing of switching the theme and the timing of displacing the display area are offset. The display control unit continues displaying the virtual image even when the abnormality detection unit detects a shift in timing.

15. The virtual image display device according to any one of claims 1 to 6, wherein: The apparatus further comprises an input grasping unit (71) for acquiring input information to an operating unit (68) for switching on and off the display of the virtual image. The display control unit stops displaying the virtual image based on the input information.

16. The virtual image display device according to any one of claims 1 to 6, wherein: The abnormality detection unit further detects an abnormality of a display unit (61) that emits display light (Lvi) for forming the virtual image. The display control unit stops display of the virtual image as the fail-safe control when the abnormality detection unit detects an abnormality in the display unit.

17. The virtual image display device according to any one of claims 1 to 6, wherein: The abnormality detection unit further detects an abnormality of a display unit (61) that emits display light (Lvi) for forming the virtual image. The display control unit continues displaying the virtual image even when the abnormality detection unit detects an abnormality in the display unit.

Images