Virtual image display device and virtual image display method

Abstract

To more hardly reduce convenience for a driver of a vehicle even when a display region of a virtual image is configured to be switchable.SOLUTION: A virtual image display device includes: a displacement mechanism which switches a position of a display region in which a virtual image is displayed between a plurality of positions including a normal position and an upper position; a display control section 73 which displays virtual images of a first content of a type to be displayed at the normal position and a second content of a type to be displayed at the upper position according to switching of the position of the display region by the displacement mechanism; and an event situation specifying section 74 for specifying the situation of a specific event. The displacement mechanism switches the display region to the upper position when the occurrence of the specific event is specified and when the position of the display region is not the upper position. The display control section 73 displays the second content before the completion of switching of the display region to the upper position when the occurrence of the specific event is specified and when the position of the display region is not the upper position.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a virtual image display device and a virtual image display method that display a virtual image that is viewable by a driver of a vehicle. [Background technology]

[0002] Patent Document 1 discloses a virtual image display device equipped with a switching mechanism that moves the position of the angle of view where a virtual image is displayed. In the technology of Patent Document 1, the range in which a virtual image can be displayed is expanded in a pseudo manner by moving the angle of view from the normal position to the superimposed position. In the technology of Patent Document 1, related content related to a specific content to be displayed at the superimposed position is displayed before the movement of the angle of view from the normal position to the superimposed position is completed. In this way, the technology of Patent Document 1 attempts to reduce the discomfort of the display caused by the time lag until the display starts due to the movement of the angle of view by the switching mechanism. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-66149 A Summary of the Invention [Problem to be solved by the invention]

[0004] Depending on the event requiring the display of a virtual image, the content to be displayed at the superimposition position must be displayed promptly after the event occurs. In contrast, in the technology of Patent Document 1, the specific content to be displayed at the superimposition position is not displayed unless the movement of the angle of view to the superimposition position is completed. Therefore, there is a risk that the content that needs to be displayed promptly after the event occurs cannot be displayed promptly. As a result, there is a risk that the convenience of the virtual image display device is impaired.

[0005] One object of this disclosure is to provide a virtual image display device and a virtual image display method that are less likely to reduce convenience for the vehicle driver, even when the display area of ​​the virtual image is configured to be switchable. [Means for solving the problem]

[0006] In order to achieve the above object, the virtual image display device disclosed herein is a virtual image display device that displays a virtual image viewable by a driver of a vehicle, and includes a switching mechanism (63) that switches the position of the display area where the virtual image is displayed between a plurality of positions including a first position and a second position, a display control unit (73) that displays virtual images of a first content, which is a type of content to be displayed at the first position, and a second content, which is a type of content to be displayed at the second position, in accordance with the switching of the position of the display area by the switching mechanism, and an event status identification unit (74) that identifies the status of a specific event, which is an event that requires the second content to be displayed, and the switching mechanism switches the display area to the second position when the event status identification unit identifies that the specific event has occurred and the position of the display area is not at the second position, and the display control unit displays the second content before the switching of the display area to the second position by the switching mechanism is completed when the event status identification unit identifies that the specific event has occurred and the position of the display area is not at the second position.

[0007] In order to achieve the above-mentioned object, the virtual image display method of the present disclosure is a virtual image display method that displays a virtual image that is visible to a driver of a vehicle, and includes a switching process executed by at least one processor for switching the position of the display area where the virtual image is displayed between a plurality of positions including a first position and a second position, a display control process for displaying virtual images of a first content, which is a type of content to be displayed at the first position, and a second content, which is a type of content to be displayed at the second position, in accordance with the switching of the position of the display area by the switching process, and an event status identification process for identifying the status of a specific event, which is an event that requires the second content to be displayed, wherein in the switching process, when it is identified in the event status identification process that a specific event has occurred and the position of the display area is not at the second position, the display area is switched to the second position, and in the display control process, when it is identified in the event status identification process that a specific event has occurred and the position of the display area is not at the second position, the second content is displayed before the switching of the display area to the second position in the switching process is completed.

[0008] According to the above configuration, when a specific event that requires the second content to be displayed occurs and the position of the display area is not the second position, the second content can be displayed before switching of the display area to the second position is completed. Therefore, it is possible to display the second content more quickly after the specific event occurs, compared to the case where the second content is displayed after switching of the display area to the second position is completed. Therefore, it is possible to display the content that must be displayed quickly after the event occurs more quickly. As a result, even if the display area of ​​the virtual image is configured to be switchable, the convenience for the driver of the vehicle is less likely to be reduced. [Brief description of the drawings]

[0009] [Figure 1] 1A and 1B are diagrams for explaining a virtual image display function of a HUD according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a block diagram showing an electrical configuration of the display system. [Diagram 3] 11 is a diagram showing the positional relationship between the normal position and the upper position of the display area, together with an example of a virtual image displayed in each display area. FIG. [Figure 4] 5 is a flowchart showing details of a display control process executed by a head-up ECU. [Diagram 5] 13 is a diagram for explaining an example of a display transition when the display area VA is moved. FIG. [Figure 6] FIG. 13 is a diagram for explaining an example of a display transition when the display area VA is moved in the case of a first situation type. [Figure 7] FIG. 13 is a diagram for explaining an example of a display transition when the display area VA is moved in the case of the second situation type. [Figure 8] FIG. 13 is a diagram for explaining an example of a display transition when the display area VA is moved in the case of the third situation type. [Figure 9] FIG. 13 is a diagram for explaining an example of a display transition when the display area VA is moved in the case of a fourth situation type. [Figure 10] FIG. 13 is a diagram showing an example of an automatic braking content displayed in an upper position. [Figure 11] FIG. 11 is a diagram showing an example of a change in the form of automatic braking content. [Figure 12] FIG. 13 is a diagram showing an example of a virtual image displayed at a normal position. [Figure 13] 13A and 13B are diagrams illustrating an example of size adjustment applied to a bar-shaped image portion displayed at both the normal position and the upper position. [Figure 14] 13A to 13C are diagrams illustrating an example of tilt adjustment applied to a line-shaped image portion displayed at both the normal position and the upper position. [Figure 15] 13A and 13B are diagrams for explaining an example of tilt adjustment applied to a line-shaped image portion displayed at an upper position. [Figure 16] FIG. 13 is a diagram showing an example of route guidance content displayed in an upper position. [Figure 17] FIG. 2 is a diagram showing an example of route guidance content. [Figure 18]FIG. 2 is a diagram showing an example of route guidance content. [Figure 19] FIG. 2 is a diagram showing an example of route guidance content. [Figure 20] FIG. 13 is a diagram showing an example of FCTA content displayed in the upper position. [Figure 21] FIG. 13 is a diagram showing an example of a pedestrian warning content displayed in an upper position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A number of embodiments for disclosure will be described with reference to the drawings. For convenience of description, in a number of embodiments, parts having the same functions as parts shown in the drawings used in the previous description may be given the same reference numerals and their description may be omitted. For parts given the same reference numerals, the description in other embodiments may be referred to.

[0011] (Embodiment 1) <Outline of the configuration of display system 1> Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings. The display system 1 shown in FIG. 1 and FIG. 2 can be used in a vehicle Am. FIG. 1 is a diagram for explaining a virtual image display function of the HUD 100. FIG. 2 is a block diagram showing an electrical configuration of the display system 1. A vehicle using the display system 1 is not necessarily limited to an automobile, but the following description will be given taking an example of use in an automobile. The display system 1 includes a meter display device 30 and a head-up display (hereinafter, HUD) 100. The HUD 100 is a virtual image display device that displays a virtual image Vi. The display system 1 presents various information related to the vehicle Am to the driver by linking the virtual image display by the HUD 100 with the screen display by the meter display device 30, etc.

[0012] The meter display device 30 and the HUD 100 are communicatively connected to a communication bus of an in-vehicle network mounted on the vehicle Am. Other in-vehicle ECUs, such as a navigation ECU (Electronic Control Unit) 21 and a driving assistance ECU 22, are further connected to the communication bus of the in-vehicle network. These components connected as nodes to the communication bus can communicate with each other. Specific nodes among these ECUs may be directly electrically connected to each other and can communicate with each other without going through the communication bus.

[0013] The navigation ECU 21 is a processing device having a processor, RAM, storage, etc., and performs route guidance to a destination set by the occupant. When the navigation ECU 21 approaches a guidance area that provides guidance on going straight, turning right or left, branching, merging, etc. during route guidance, the navigation ECU 21 provides route information for the guidance area to the HUD 100 and the meter display device 30.

[0014] The driving assistance ECU 22 is a processing device having a processor, RAM, storage, etc., and realizes a plurality of driving assistance functions that assist the driver of the vehicle A. Examples of the driving assistance functions include Lane Departure Warning (LDW), Adaptive Cruise Control (ACC), Front Cross Traffic Alert (FCTA), Pre Crash Safety system (PCS), Proactive Driving Assist (PDA), etc.

[0015] The driving assistance ECU 22 uses the LDW function to determine whether the vehicle has deviated from the lane, such as going beyond the marking lines Lml and Lmr, based on the detection information of the marking lines obtained from the surrounding monitoring sensor. When the driving assistance ECU 23 determines that the vehicle has deviated from the lane, it provides lane departure information to the HUD 100 and the meter display device 30 and issues a lane departure warning to the driver.

[0016] The driving assistance ECU 22 uses the ACC function to make the vehicle Am travel at a constant speed or follow-up travel. "Constant speed travel" refers to making the vehicle A travel at a constant speed at a target vehicle speed. "Follow-up travel" refers to making the vehicle Am follow the vehicle ahead while maintaining a distance from the vehicle ahead. When the ACC function is operating, the driving assistance ECU 22 provides the HUD 100 and the meter display device 30 with status information indicating the control state of the ACC function.

[0017] The meter display device 30 is one of a plurality of display devices mounted on the vehicle Am. The meter display device 30 presents information to the driver by displaying an image on a display screen. The meter display device 30 corresponds to a combination meter. The meter display device 30 is accommodated 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.

[0018] The meter display 31 is, for example, a liquid crystal display or an organic EL display. The meter display 31 displays various images on a display screen based on video data acquired from the meter ECU 32. The images displayed on the meter display 31 include, for example, a speedometer image, a tachometer image, a navigation map image, and a driving assistance image.

[0019] The meter ECU 32 is an electronic control device that manages the user interface functions of the vehicle Am. The meter ECU 32 comprehensively controls the display by display devices such as the meter display 31, the HUD 100, and the center display. The meter ECU 32 mainly includes a computer equipped with a processing unit, a RAM, a storage, an input / output interface, and a bus connecting these. The meter ECU 32 generates video data to be provided to the meter display 31 based on various information output to the communication bus. The meter ECU 32 cooperates with the head-up ECU 70 described later and executes arithmetic processing for displaying a virtual image. The meter ECU 32 generates image data used to display the virtual image Vi, and sequentially outputs the generated image data to the HUD 100.

[0020] The HUD 100 is one of a plurality of display devices mounted on the vehicle Am. The HUD 100 presents information to the driver by a virtual image Vi formed in a 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 light formed as the virtual image Vi toward a projection range PA of the windshield WS. The light formed as the virtual image Vi is hereinafter referred to as display light Lvi. The display light Lvi projected on the windshield WS is reflected toward the driver's seat in the projection range PA and is perceived by the driver. The driver visually recognizes a display in which the virtual image Vi is superimposed on the foreground seen through the projection range PA.

[0021] 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 .

[0022] 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 with the display surface of the LCD panel facing the magnifying optical system 62. The magnifying optical system 62 is a plane mirror, which will be described later. The PGU 61 displays each frame image of the video data on the display surface of the LCD panel, and transmits and illuminates the display surface with a backlight. The PGU 61 thereby emits display light Lvi, which is focused as a virtual image Vi, toward the magnifying optical system 62.

[0023] The magnifying optical system 62 includes at least a plane mirror and a concave mirror 62a, which are formed by depositing a metal such as aluminum on the surface of a base material made of synthetic resin or glass. The plane mirror reflects the display light Lvi emitted from the PGU 61 toward the concave mirror 62a. The concave mirror 62a projects the display light Lvi incident from the plane mirror into the projection range PA above while expanding the light by reflection.

[0024] The displacement mechanism 63 is a mechanism that mechanically moves an area of ​​the windshield WS that becomes the projection range PA. The displacement mechanism 63 corresponds to a switching mechanism. The projection range PA is a range in which the display light Lvi is projected. The projection range PA is a range in which the virtual image Vi is displayed as seen by the driver. The displacement mechanism 63 includes an actuator 63a, a gear unit, and the like. The displacement mechanism 63 transmits the driving force of the actuator 63a to the housing of the concave mirror 62a via the gear unit. By transmitting the driving force in this manner, the displacement mechanism 63 rotates the concave mirror 62a around a rotation axis defined along the left-right direction Yo. The displacement mechanism 63 increases or decreases the tilt angle of the concave mirror 62a, and changes the emission direction of the display light Lvi from the concave mirror 62a toward the windshield WS. Due to such a change in the attitude of the concave mirror 62a, the projection range PA of the display light Lvi moves at least in the up-down direction US. Furthermore, by moving the projection range PA in this way, the position of the display area VA visually recognized by the driver also moves at least in the vertical direction US.

[0025] More detailed description is as follows. The display area VA is defined based on a virtual line connecting the driver's eye point EP and the outer edge of the imaging surface IS. The imaging surface IS is a virtual range in space where a virtual image Vi can be formed. The display area VA is the range of the angle of view in which the virtual image Vi is displayed as seen from the eye point EP. In the HUD 100, the horizontal angle of view in the horizontal direction is larger than the vertical angle of view in the vertical direction. The vertical direction corresponds to the up-down direction US in FIG. 1. The horizontal direction corresponds to the left-right direction Yo in FIG. 1. The vertical angle of view is, for example, about 2°. The horizontal angle of view is, for example, about 6°.

[0026] The displacement mechanism 63 displaces the position of the display area VA along the up-down direction US of the vehicle Am. This moves the forward range that overlaps with the display area VA in the fore-aft direction ZG. The forward range is the range in the foreground. As an example, if the displacement mechanism 63 positions the display area VA downward at a depression angle of about 4°, the range within the display area VA is about 10 to 20 meters forward from the vehicle Am. On the other hand, if the displacement mechanism 63 positions the display area VA upward at a depression angle of about 2°, the range within the display area VA is about 20 to 60 meters forward from the vehicle Am.

[0027] Here, the longitudinal direction ZG and the lateral direction Yo are defined based on the vehicle Am stationary on a horizontal plane. Specifically, the longitudinal direction ZG is defined along the longitudinal direction of the vehicle Am. The longitudinal direction of the vehicle Am can be rephrased as the traveling direction of the vehicle Am. The lateral 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 that defines the longitudinal direction ZG and the lateral direction Yo. Note that, for the sake of simplicity, the symbols indicating each direction may be omitted as appropriate.

[0028] 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.

[0029] The head-up ECU 70 is a control circuit of the HUD 100 that performs integrated control of the PGU 61 and the actuator 63a. The head-up ECU 70 mainly includes a computer equipped with a processing unit 51, a RAM 52, a storage 53, an input / output interface, and a bus connecting these. In the following, the computer is described as, for example, a microcomputer. The head-up ECU 70 is further provided with a drive circuit and a detection circuit. The drive circuit is a drive circuit for driving the LCD panel, the backlight, and the actuator 63a. The detection circuit is a detection circuit for acquiring an output signal from the position sensor 64.

[0030] The head-up ECU 70 changes the content CT (see FIG. 3) to be displayed as a virtual image Vi in association with the position of the display area VA. Specifically, the head-up ECU 70 switches the position of the display area VA where the virtual image Vi is displayed between a plurality of positions including a normal position VP1 and an upper position VP2. The head-up ECU 70 performs this switching in cooperation with the displacement mechanism 63 by controlling the drive of the actuator 63a. The head-up ECU 70 displays the virtual image Vi corresponding to each of the normal position VP1 and the upper position VP2 in response to the switching of the position of the display area VA. FIG. 3 is a diagram showing the positional relationship between the normal position VP1 and the upper position VP2 of the display area VA together with an example of the virtual image Vi displayed in the display area VA.

[0031] The normal position VP1 is a position of the display area VA where a virtual image Vi is displayed in the peripheral visual field PVF (see FIG. 3) of the driver. The normal position VP1 corresponds to the first position. The 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 permanent position that is used for a longer period of time than the upper position VP2. In the display area VA at the normal position VP1, a content CT indicating vehicle information, such as a vehicle speed content CTv (see FIG. 3), is displayed. The vehicle speed content CTv indicates the current vehicle speed of the vehicle Am. The vehicle speed content CTv indicates the current vehicle speed of the vehicle Am in text. In the following description, the content CT corresponding to the normal position VP1 is called the first content CT1 (see FIG. 3). The driver can recognize the virtual image Vi of the first content CT1 displayed in the display area VA at the normal position VP1 at the timing when the driver wants to obtain information.

[0032] The information displayed in the first content CT1 includes the vehicle speed CTv and the shift content. The shift content indicates the current shift position of the vehicle Am. The shift content indicates the current shift position of the vehicle Am with text such as "D" and "R". The information displayed in the first content CT1 may include map-related information such as intersection names. The information displayed in the first content CT1 may include information indicating the vehicle status other than the vehicle speed and shift position. The first content CT1 is displayed at a specific position within the projection range PA at the normal position VP1 below the upper position VP2, without specifying a superimposition target. As a result, the first content CT1 is visually recognized by the driver as if it is fixed relatively to the vehicle configuration such as the windshield WS.

[0033] The upper position VP2 is a position of the display area VA where the virtual image Vi is displayed so as to overlap the central visual field CVF of the driver (see FIG. 3). The upper position VP2 corresponds to the second position. The upper position VP2 is defined above the normal position VP1 so as not to overlap with the normal position VP1. The display area VA is moved from the normal position VP1 to the upper position VP2 when a specific event occurs. The specific event is an event that requires displaying the second content CT2 of the type to be displayed at the upper position VP2. The specific event is, for example, approaching a guidance area, activation of a driving assistance function, etc. Approaching the guidance area may be determined by the head-up ECU 70 when the distance between the guidance area and the vehicle Am becomes equal to or less than a specified distance.

[0034] In the display area VA at the upper position VP2, the second content CT2 related to a specific event is displayed. The second content CT2 shown as an example in FIG. 3 is a route guidance content CTrg. The route guidance content CTrg is a so-called turn-by-turn display. The route guidance content CTrg is the second content CT2 related to a specific event, namely, approaching a guidance area. An example of the second content CT2 other than the route guidance content CTrg is a driving support content related to the support content in the driving support function. The second content CT2 displayed in the display area VA at the upper position VP2 can be recognized by the driver without significantly deviating his / her line of sight from the front. The second content CT2 is displayed at a specific position within the projection range PA at the upper position VP2 above the normal position VP1, without specifying a superimposed target. In other words, the second content CT2 is not an AR display object used for Augmented Reality (AR) display. The AR display object is displayed superimposed on a specific superimposed target within the angle of view VA. The AR display object is movable as seen by the driver, following the specific superimposed object, as if it were fixed relatively to the specific superimposed object.

[0035] The relative positional relationship between the normal position VP1 and the upper position VP2 may be changed as appropriate. For example, the lower edge of the upper position VP2 may be in contact with the upper edge of the normal position VP1, or may be slightly spaced upward 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 may partially overlap.

[0036] The head-up ECU 70 executes a virtual image display program stored in the storage 53 to realize virtual image display control linking the display area VA and the content. The head-up ECU 70 has a plurality of functional blocks for this virtual image display control. The head-up ECU 70 has, as these functional blocks, an information acquisition unit 71, a data storage unit 72, a display control unit 73, and an abnormality detection unit 74. Moreover, the execution of the processing of each functional block of the head-up ECU 70 by a computer corresponds to the execution of a vehicle control method.

[0037] The information acquisition unit 71 acquires information related to virtual image display. The information acquisition unit 71 is connected to the communication bus and the meter ECU 32. The information acquisition unit 71 acquires route information provided by the navigation ECU 21 from the communication bus. The information acquisition unit 71 acquires target information and control status information around the vehicle provided by the driving assistance ECU 22 from the communication bus. Image data for virtual image display generated by the meter ECU 32 is sequentially input to the information acquisition unit 71.

[0038] The information acquisition unit 71 is electrically connected to the operation unit 68. The operation unit 68 is a switch for adjusting the position of the display area VA by the driver and switching on and off the display of the virtual image Vi. For example, the operation unit 68 may be a dedicated switch provided on the instrument panel 9. The operation unit 68 may be a steering switch provided on the steering wheel. The operation unit 68 may be a center display having a touch panel function. The operation unit 68 may be a voice input device that detects the driver's speech. When the operation unit 68 is operated by the driver or the like, the information acquisition unit 71 acquires input information input to the operation unit 68. The input information is provided from the information acquisition unit 71 to the display control unit 73, and the position of the display area VA is adjusted and the virtual image display is switched on and off according to the driver's operation.

[0039] The data storage unit 72 is a storage area that stores a plurality of data referenced by the display control unit 73. The data storage unit 72 may be a storage area secured in the RAM 52, or may be a part of a storage area in the storage 53. In the data storage unit 72, a lookup table, mirror position data, and graphic data are prepared so as to be able to be referenced by the display control unit 73.

[0040] The lookup table is information that links the display area VA to the content CT. Furthermore, the lookup table records information that links the type of failure that has occurred in the HUD 100 to a method of avoiding the failure. The mirror position data of the normal position VP1 is information that specifies the angular position of the concave mirror 62a when the display area VA is set to the normal position VP1. The mirror position data of the upper position VP2 is information that specifies the angular position of the concave mirror 62a when the display area VA is set to the upper position VP2. Each mirror position data may be a value that can be adjusted by the driver so as to match the position of the driver's eye point EP. The graphic data of the normal position VP1 is image data that is used when the display area VA is in the normal position VP1. The graphic data of the upper position VP2 is image data that is used when the display area VA is in the upper position VP2. The graphic data at the time of downward transition is image data that is used when the display area VA is in the process of transitioning toward the normal position VP1. These image data are called material data.

[0041] The display control unit 73 is a control unit that performs integrated control of the PGU 61 and the actuator 63a. The switching of the position of the display area VA in the displacement mechanism 63 is performed by the control of the actuator 63a of the display control unit 73. Therefore, the process of switching the position of the display area VA in the display control unit 73 corresponds to a switching process. The display control unit 73 generates video data and a control signal to be output to the PGU 61, and a drive signal to be output to the actuator 63a. The display control unit 73 selects the content CT to be displayed as the virtual image Vi, and controls the position of the display area VA according to the contents of the content CT to be displayed. The process of displaying the content CT in the display control unit 73 corresponds to a display control process.

[0042] In detail, the display control unit 73 refers to the lookup table of the data storage unit 72 based on the information acquired by the information acquisition unit 71. Then, the display control unit 73 selects the content CT to be displayed as a virtual image and the position of the display area VA based on the result of the reference. The display control unit 73 extracts material data of the image to be used for generating the video data from the RAM 52 or the storage 53 based on the selection result of the content CT. The display control unit 73 appropriately combines the image data generated from the material data with the image data provided by the meter ECU 32 to generate each frame image of the video data. The display control unit 73 sequentially outputs the video data consisting of a large number of consecutive frame images to the PGU 61.

[0043] The display control unit 73 displays the virtual images Vi of the first content CT1 to be displayed at the normal position VP1 and the second content CT2 to be displayed at the upper position VP2 in response to switching of the position of the display area VA by the displacement mechanism 63. When switching of the position of the display area VA is performed, the display area VA transitions between the normal position VP1 and the upper position VP2 in response to driving of the actuator 63a. Even during this transition, the display control unit 73 displays the content CT to suppress discomfort caused by the display being interrupted. Details of switching of the position of the display area VA and switching of the content CT to be displayed by the display control unit 73 will be described later.

[0044] The event status identification unit 74 identifies the status of the specific event. The processing in this event status identification unit 74 corresponds to an event status identification step. Examples of the status of the specific event identified by the event status identification unit 74 include the occurrence of a specific event and the end of a specific event. The event status identification unit 74 identifies the status of the specific event from information acquired by the information acquisition unit 71 from the navigation ECU 21 and the driving assistance ECU 22. An example is as follows. Approaching a guidance area may be identified as the start of a specific event. Passing through a guidance area may be identified as the end of a specific event. The start of driving assistance by the driving assistance function may be identified as the start of a specific event. The end of driving assistance by the driving assistance function may be identified as the end of a specific event. The event status identification unit 74 may identify the start and end of a specific event for each specific event.

[0045] The situation type identification unit 75 identifies a situation type that is either a situation type of occurrence of a specific event or a situation type of end of a specific event. When a specific event is occurring and the display area VA is located at the upper position VP2, the situation type identification unit 75 preferably identifies a first situation type that a new specific event has occurred, the set priority of which is higher than that of the specific event. The occurrence of a specific event refers to a situation in which the specific event has started but not ended, and no new specific event has occurred. The priority is set in advance for each type of specific event. As an example, the higher the priority of a specific event, the higher the urgency of the event. For example, the priority of the driving assistance of the PCS may be set higher than the approach of the guidance area. In this case, the situation in which the approach of the guidance area occurs and the second content CT2 regarding the approach of the guidance area is displayed at the upper position VP2, and the driving assistance of the PCS occurs corresponds to the first situation type.

[0046] It is preferable that the situation type identification unit 75 identifies a second situation type in which a specific event ends while the displacement mechanism 63 is in the process of switching the position of the display area VA to the upper position VP2 due to the occurrence of the specific event. The situation type identification unit 75 may identify that the displacement mechanism 63 is in the process of switching the position of the display area VA to the upper position VP2 by monitoring the actuator 63a.

[0047] It is preferable that the situation type identification unit 75 identifies a third situation type in which a new specific event has occurred while a specific event is occurring and the set priority is higher than that of the specific event while the displacement mechanism 63 is switching the position of the display area VA to the upper position VP2.

[0048] It is preferable that the situation type identification unit 75 identifies a fourth situation type in which a new specific event has occurred while the displacement mechanism 63 is switching the position of the display area VA to the lower position VP1 due to the end of a specific event. The situation type identification unit 75 may identify that the displacement mechanism 63 is in the process of switching the position of the display area VA to the lower position VP1 by monitoring the actuator 63a.

[0049] The abnormality detection unit 76 is connected to the PGU 61, the actuator 63a, and the position sensor 64. Thus, the abnormality detection unit 76 detects various abnormalities occurring in the HUD 100, such as an abnormality in the displacement of the display area VA and an abnormality in the image. Specifically, the abnormality detection unit 74 detects an abnormality in the PGU 61, an abnormality in the actuator 63a, and a malfunction of the gear unit. In addition to these, the abnormality detection unit 74 also detects a circuit abnormality in the head-up ECU 70 and a software abnormality in the virtual image display program. When the display control unit 73 detects an abnormality in the HUD 100, it is sufficient to display information indicating the abnormality detection and information indicating the type of the detected abnormality. The display control unit 73 may display this information by outputting image data that displays the information as a virtual image to the PGU 61. When the display control unit 73 detects an abnormality in the HUD 100, it is sufficient to prevent the display on the HUD 100. <Display control processing>

[0050] Next, an example of a display control process performed mainly by the display control unit 73 in the head-up ECU 70 will be described with reference to the flowchart of Fig. 4. The display control unit 73 may start the display control process when the power supply to the HUD 100 is started and the power supply to the head-up ECU 70 is turned on. In the display control process, occurrence of a fault related to the virtual image display is constantly monitored. The display control process is repeatedly performed until the power supply to the head-up ECU 70 is turned off.

[0051] First, in step S101, the display control unit 73 determines whether or not a fault has occurred in the virtual image display based on whether or not abnormality detection information has been acquired from the abnormality detection unit 74. If abnormality detection information has been acquired and it has been determined that a fault has occurred (YES in S101), the process proceeds to step S102. On the other hand, if abnormality detection information has not been acquired from the abnormality detection unit 74 and it has been determined that no fault has occurred (NO in S101), the process proceeds to step S104.

[0052] In step S102, the display control unit 73 determines the type of fault based on the abnormality type information acquired from the abnormality detection unit 74. In step S103, the display control unit 73 selects a method of avoiding the fault. In detail, the display control unit 73 selects an avoidance method that is pre-linked to the type of fault determined in S102 by referring to a lookup table in the data storage unit 72. Then, the display control unit 73 performs a fail-safe display process according to the selected avoidance method. In the fail-safe display process, a display process is performed to change the content of the virtual image display so as not to hinder normal driving by the driver.

[0053] In step S104, the display control unit 73 determines the position of the display area VA to be set as the position to be displayed. More specifically, the display control unit 73 selects the content CT to be displayed as a virtual image and the position of the display area VA. The display control unit 73 may perform this selection by referring to a lookup table in the data storage unit 72 based on the information acquired by the information acquisition unit 71. If it is determined that the display area VA is to be set to the upper position VP2 (YES in S104), the process proceeds to step S108. On the other hand, if it is determined that the display area VA is to be set to the normal position VP1 (NO in S104), the process proceeds to step S105.

[0054] In step S105, the display control unit 73 reads mirror position data associated with the normal position VP1 from the data storage unit 72. In step S106, the display control unit 73 reads graphic data associated with the normal position VP1 from the data storage unit 72. In step S107, the display control unit 73 displays the virtual image Vi of the content CT determined to be displayed in S104 in the display area VA of the normal position VP1. Then, the process returns to S101 and is repeated.

[0055] On the other hand, in step S108, the display control unit 73 reads mirror position data associated with the upper position VP2 from the data storage unit 72. In step S109, the display control unit 73 reads graphic data associated with the upper position VP2 from the data storage unit 72. In step S110, the display control unit 73 displays the virtual image Vi of the content CT determined to be displayed in S104 in the display area VA of the upper position VP2. Then, the process returns to S101 and is repeated.

[0056] <Display switching timing> When the event status identification unit 74 identifies that a specific event has occurred, the display control unit 73 displays the second content CT2 at the upper position VP2. However, if the display area VA is not at the upper position VP2, the second content CT2 cannot be displayed at the upper position VP2 the moment it is identified that a specific event has occurred. It takes time to move the display area VA to the upper position VP2 after it is identified that a specific event has occurred. This is described in more detail below.

[0057] First, there is a processing time in the microcomputer of the head-up ECU 70 (hereinafter, M processing time). The M processing time is the time required to select the content CT to be displayed as a virtual image and the position of the display area VA. Next, there is a time required for communication between the head-up ECU 70 and the displacement mechanism 63 (hereinafter, communication time). This communication time is the time required for the head-up ECU 70 to transmit to the displacement mechanism 63 an instruction to drive and control the actuator 63a to the position of the display area VA selected by the head-up ECU 70. There is also a time required for the displacement mechanism 63 to control the actuator 63a (hereinafter, active control time). The active control time is the time required from when the displacement mechanism 63 receives an instruction to drive and control the actuator 63a to when it starts driving the actuator 63a. There is also a time required for the actuator 63a to operate (hereinafter, active operation time). The active operation time is the time required for the actuator 63a to move the display area VA to the position of the designated display area VA. The M processing time, communication time, active control time, and active operation time are hereinafter collectively referred to as delay time.

[0058] If the second content CT2 is displayed after the occurrence of a specific event is identified and the display area VA is moved to the upper position VP2, the following problem occurs. More specifically, due to the above-mentioned delay time, there is a time gap between the occurrence of the specific event and the display of the second content CT2. This may result in the content that needs to be displayed promptly after the event occurrence not being displayed promptly.

[0059] On the other hand, when the event status identification unit 74 identifies that a specific event has occurred and the position of the display area VA is not at the upper position VP2, the display control unit 73 performs the following operations: The display control unit 73 instructs the displacement mechanism 63 to switch the display area VA to the upper position VP2. The display control unit 73 also displays the second content CT2 before the displacement mechanism 63 has completed switching of the display area VA to the upper position VP2 (see FIG. 5).

[0060] FIG. 5 is a diagram for explaining an example of a display transition when the display area VA is moved. CTT in the figure indicates the transition content. CT1 in the figure indicates the first content CT1. CT2 in the figure indicates the second content CT2. As an example, the transition content is a combination of the vehicle speed content CTv and the shift content. The transition content is a content that includes at least a part of the first content CT1. The first content is as described above. As an example, the second content CT2 is a driving support content or a route guidance content CTg plus the vehicle speed content CTv and the shift content. ES in the figure indicates the timing of the start of a specific event. EE in the figure indicates the timing of the end of a specific event. P in the figure indicates the M processing time. C in the figure indicates the communication time. SR in the figure indicates the timing at which the displacement mechanism 63 receives an instruction from the head-up ECU 70. MC in the figure indicates the active control time. MB in the figure indicates the active operation time. The same applies to the subsequent figures.

[0061] According to the above configuration, it is possible to display the second content CT2 more quickly after the occurrence of a specific event. Therefore, it is possible to display the content that must be displayed quickly after the occurrence of an event more quickly. As a result, even if the display area VA of the virtual image is configured to be switchable, the convenience for the driver of the vehicle Am is less likely to be reduced. As shown in the example of FIG. 5, the above-mentioned delay time is required from the occurrence of a specific event until the display area VA is switched to the upper position VP2. It takes at least M processing time to elapse from the occurrence of a specific event until the second content CT2 for the specific event is selected as the display content. Therefore, when a specific event occurs, the display control unit 73 may display the second content CT2, for example, immediately after the elapse of this M processing time. Thereby, the second content CT2 may be displayed before the switching of the display area VA to the upper position VP2 is completed.

[0062] When the event status identification unit 74 identifies that a specific event has occurred and the position of the display area VA is the normal position VP1, the display control unit 73 preferably performs the following. The display control unit 73 instructs the displacement mechanism 63 to switch the display area VA from the normal position VP1 to the upper position VP2. The display control unit 73 may display the second content CT2 from the timing when the display area VA is located at the normal position VP1 before the displacement mechanism 63 completes switching of the display area VA from the normal position VP1 to the upper position VP2 (see FIG. 5). For example, as described above, the second content CT2 may be displayed immediately after the M processing time has elapsed when the occurrence of a specific event has been identified.

[0063] According to the above configuration, when a specific event occurs, it becomes possible to display the second content CT2 from the timing when the display area VA is located at the normal position VP1. Therefore, even when the display area VA is located at the normal position VP1, it becomes possible to more quickly display the content that needs to be displayed promptly after the occurrence of an event.

[0064] Furthermore, when the event status determination unit 74 determines that all of the specific events have ended, the display control unit 73 displays the first content CT1 at the normal position VP1. However, the first content CT1 cannot be displayed at the normal position VP1 the instant that it is determined that the specific event has ended. After it is determined that the specific event has ended, the above-mentioned M processing time, communication time, active control time, and active operation time are also required to move the display area VA to the normal position VP1.

[0065] In order to display the first content CT1 after the specific event ends, it is necessary to end the display of the second content CT2. If it is determined that all the specific events have ended, and then the display area VA is moved to the normal position VP1, and then the display of the second content CT2 is ended, the following problem occurs. In detail, due to the above-mentioned delay time, there is a time gap between the occurrence of the specific event and the end of the display of the second content CT2. This may cause the content for the event to be unable to be ended promptly even though the event has ended. As a result, the driver may feel uncomfortable, and the convenience for the driver may be reduced.

[0066] In response to this, when the event status identification unit 74 has identified the ends of all the specific events whose starts have been identified, the display control unit 73 may do the following: The display control unit 73 instructs the displacement mechanism 63 to switch the display area VA to the normal position VP1. Furthermore, the display control unit 73 may end the display of the second content CT2 and display the transition content before the displacement mechanism 63 has completed switching of the display area VA to the normal position VP1 (see FIG. 5). The display control unit 73 may display the first content CT1 after the display area VA has been switched to the normal position VP1, as shown in FIG. 5.

[0067] According to the above configuration, it is possible to more quickly end the display of the second content CT2 after all the specific events have ended. Therefore, it is possible to more quickly end the display of the content for the ended event. As a result, even if the display area VA of the virtual image is configured to be switchable, the convenience for the driver of the vehicle Am is less likely to be reduced. As shown in the example of FIG. 5, the above-mentioned delay time is required from the end of the specific event until the display area VA is switched to the normal position VP1. At least M processing time is required from the end of the specific event until the transition content CTT is selected as the display content. Therefore, when the specific event has ended, the display control unit 73 may display the transition content CTT, for example, immediately after the M processing time has elapsed. Thereby, the display of the second content CT2 may be ended and the transition content CTT may be displayed before the switching of the display area VA to the normal position VP1 is completed.

[0068] When the event status identification unit 74 has identified the ends of all the specific events whose starts have been identified, and the position of the display area VA is the upper position VP2, it is preferable for the display control unit 73 to do the following. The display control unit 73 instructs the displacement mechanism 63 to switch the display area VA from the upper position VP2 to the normal position VP1. The display control unit 73 may end the display of the second content CT2 and display the transition content from the timing when the display area VA is located at the upper position VP2, before the displacement mechanism 63 has completed switching of the display area VA from the upper position VP2 to the normal position VP1.

[0069] According to the above configuration, when all the specific events have ended, it is possible to end the display of the second content CT2 from the timing when the display area VA is located at the upper position VP2. Therefore, even when the display area VA is located at the upper position VP2, it is possible to more quickly end the display of the content for the ended event.

[0070] <Transition of display area and displayed content according to the type of situation>

[0071] It is considered that the timing of the transition of the display area and the displayed content differs depending on the situation of the event that requires the display of a virtual image, in order to notify the driver of information without causing discomfort. In contrast, Patent Document 1 does not assume that the timing of the transition of the display area and the displayed content will be different depending on the situation of the event. Therefore, with the technology of Patent Document 1, there is a risk that the transition of the display area and the displayed content will be performed in a way that causes discomfort to the driver depending on the situation of the event. As a result, there is a risk that convenience for the occupants will be impaired.

[0072] In response to this, it is preferable that the display control unit 73 performs the following processes at a timing according to the situation type identified by the situation type identification unit 75. The display control unit 73 instructs the displacement mechanism 63 to switch the display area VA at a timing according to the identified situation type. The display control unit 73 switches the content CT to be displayed at a timing according to the identified situation type.

[0073] According to the above configuration, it is possible to transition the display area and the displayed content so that the driver is notified of information without feeling uncomfortable depending on the situation of the event that requires the display of the virtual image. As a result, even if the display area VA of the virtual image is configured to be switchable, the convenience for the driver of the vehicle Am is further unlikely to be reduced.

[0074] An example of the transition of the display area VA and the displayed content CT according to the type of situation will be described below with reference to Figures 6 to 9. Figures 6 to 9 are diagrams for explaining an example of the display transition when the display area VA is moved according to the type of situation. Among the symbols in Figures 6 to 9, the same symbols as those in Figure 5 are the same as those described above and will not be described again.

[0075] When the situation type identification unit 75 identifies the first situation type, the display control unit 73 preferably performs the following. The first situation type is a situation in which a specific event is occurring and the position of the display area VA is at the upper position VP2, and a new specific event occurs with a set priority higher than that of the specific event. This new specific event is hereinafter referred to as a priority new event. The display control unit 73 may maintain the position of the display area VA at the upper position VP2 without switching it from the upper position VP2 to the normal position VP1 (see FIG. 6). In this case, since the display control unit 73 maintains the display area VA at the upper position VP2, it is not necessary to instruct the displacement mechanism 63 again. The display control unit 73 may start displaying the second content CT2 for the priority new event from the timing when the situation type identification unit 75 identifies the first situation type. This allows the second content CT2 for the priority new event to be displayed (see FIG. 6). Here, the start of display of the second content CT2 refers to the timing when a display instruction is given from the HUD 70, and is the timing before the second content CT2 is actually displayed. HNES in Fig. 6 indicates the timing when the priority new event starts. CTN in Fig. 6 indicates the second content CT2 for the priority new event. Hereinafter, the second content CT2 for the priority new event will be referred to as new content CTN.

[0076] According to the above configuration, even if a priority new event occurs during the occurrence of a specific event, it is not necessary to end the specific event and switch the position of the display area VA from the upper position VP2 to the normal position VP1. Therefore, the time from the occurrence of the priority new event to the display of the new content CTN can be shortened by this amount. In addition, it is possible to start displaying the new content CTN from the timing when it is determined that the priority new event has occurred. Therefore, it is possible to display the new content CTN more quickly without waiting for the end of the previous event. Therefore, it is less likely to give the driver a sense of incongruity regarding the display of the new content CTN in response to the occurrence of the priority new event. As a result, even if the display area VA of the virtual image is configured to be switchable, it is less likely to reduce the convenience for the driver of the vehicle Am. As shown in the example in FIG. 6, when a priority new event occurs during the occurrence of a specific event, it is sufficient to display the new content CTN immediately after the M processing time for the priority new event has elapsed. This makes it possible to display the new content CTN more quickly without waiting for the end of the previous event.

[0077] When the situation type identification unit 75 identifies the second situation type, the display control unit 73 preferably performs the following. The second situation type is a situation in which a specific event ends while the displacement mechanism 63 is switching the position of the display area VA to the upper position VP2 due to the occurrence of the specific event. The display control unit 73 instructs the displacement mechanism 63 to change the position of the display area VA to the normal position VP1 even if the position has not been switched to the upper position VP2 (see FIG. 7). In the example of FIG. 7, the position of the display area VA is changed to the normal position VP1 without reaching the upper position VP2. The display control unit 73 may start to end the display of the second content CT2 from the timing when the situation type identification unit 75 identifies the second situation type. This may end the display of the second content CT2. Then, the display of the transition content CTT may be started to be displayed (see FIG. 7). Here, the start of the end of the display of the second content CT2 refers to the timing when an instruction to switch the display is given from the HUD 70, and is a timing before the display of the second content CT2 is actually ended. Also, the start of the display of the transition content CTT refers to the timing when an instruction to display is given from the HUD 70, and is a timing before the transition content CTT is actually displayed. Also, after the position of the display area VA reaches the normal position VP1, the display control unit 73 may display the first content CT1.

[0078] According to the above configuration, when a specific event ends while the position of the display area VA is being switched to the upper position VP2, it is not necessary to once make the position of the display area VA reach the upper position VP2. Therefore, it is possible to suppress unnecessary movement of the display area VA to a small extent. Therefore, it is possible to suppress the driver from feeling uncomfortable due to unnecessary movement of the display area VA. In addition, it is possible to start displaying the transition content CTT even if the position of the display area VA has not reached the upper position VP2. Therefore, it is possible to switch the display to the transition content CTT more quickly than when switching to the display of the transition content CTT after waiting for the position of the display area VA to reach the upper position VP2. Therefore, it is possible to more quickly end the display of the content for the ended event. As a result, even if the display area VA of the virtual image is configured to be switchable, the convenience for the driver of the vehicle Am is further unlikely to be reduced. As shown in the example in FIG. 7, when a specific event ends while the position of the display area VA is being switched to the upper position VP2, the transition content CTT may be displayed immediately after the M processing time for the end of the specific event has elapsed. This makes it possible to quickly end the display of the second content CT2 after the specific event ends, and to more quickly display the new content CTN.

[0079] When the situation type specification unit 75 specifies the third situation type, the display control unit 73 preferably performs the following. The third situation type is a situation in which a specific event is occurring and a priority new event occurs while the displacement mechanism 63 is switching the position of the display area VA to the upper position VP2. The display control unit 73 instructs the displacement mechanism 63 to continue switching the position of the display area VA to the upper position VP2 without switching it from the upper position VP2 to the normal position VP1 (see FIG. 8). The display control unit 73 may start displaying the new content CTN from the timing when the situation type specification unit 75 specifies the third situation type. This allows the new content CTN to be displayed (see FIG. 8). The start of displaying the new content CTN here refers to the timing when the HUD 70 issues a display instruction, which is a timing before the new content CTN is actually displayed. In the example of FIG. 8, new content CTN is displayed before the display area VA reaches the upper position VP2, without waiting for the second content CT2 for the immediately previous specific event to be displayed at the upper position VP2.

[0080] According to the above configuration, when a priority new event occurs while the position of the display area VA is being switched to the upper position VP2 due to the occurrence of a specific event, it is not necessary to end the specific event and switch the position of the display area VA from the upper position VP2 to the normal position VP1. Therefore, the time from the occurrence of the priority new event to the display of the new content CTN can be shortened by this amount. As a result, even if the display area VA of the virtual image is configured to be switchable, the convenience for the driver of the vehicle Am is further unlikely to be reduced. As shown in the example in FIG. 8, when a priority new event occurs during the occurrence of a specific event, the new content CTN may be displayed immediately after the M processing time for the priority new event has elapsed. This may be performed even if the display area VA is moving to the upper position VP2. This makes it possible to display the new content CTN more quickly without waiting for the end of the previous event.

[0081] When the situation type identification unit 75 identifies the fourth situation type, the display control unit 73 preferably performs the following. The fourth situation type is a situation in which a new specific event occurs while the displacement mechanism 63 is switching the position of the display area VA to the lower position VP1 due to the end of a specific event. The display control unit 73 instructs the displacement mechanism 63 to change the position of the display area VA to the upper position VP2 even if the position has not been switched to the normal position VP1 (see FIG. 9). In the example of FIG. 9, the position of the display area VA is changed to the upper position VP2 without reaching the normal position VP1. Note that, in relation to the delay time, there may be cases in which the position of the display area VA is changed to the upper position VP2 after reaching the normal position VP1. The display control unit 73 starts displaying the second content CT2 for the new specific event from the timing when the situation type identification unit 75 identifies the fourth situation type. This causes the second content CT2 for the new specific event to be displayed (see FIG. 9). 9 indicates the start timing of a new specific event. When the fourth situation type is identified, the display control unit 73 may display the second content CT2 for the new specific event even when the position of the display area VA is in the normal position VP1.

[0082] According to the above configuration, when a new specific event occurs while the position of the display area VA is being switched to the normal position VP1 due to the end of a specific event, it is not necessary to make the position of the display area VA reach the normal position VP1 once. Therefore, it is possible to suppress unnecessary movement of the display area VA to a small extent. Therefore, it is possible to suppress the driver from feeling uncomfortable due to unnecessary movement of the display area VA. In addition, even if the position of the display area VA has not reached the upper position VP2, it is possible to quickly start displaying the second content CT2 for the new specific event. Therefore, it is possible to switch the display to the second content CT2 more quickly than waiting for the position of the display area VA to reach the upper position VP2 and then switching to the display of the second content CT2. As a result, even if the display area VA of the virtual image is configured to be switchable, the convenience for the driver of the vehicle Am is further unlikely to be reduced. As shown in the example in FIG. 9, when a new specific event ends while the position of the display area VA is being switched to the normal position VP1 due to the end of a specific event, the second content CT2 may be displayed immediately after the M processing time for the new specific event has elapsed. This makes it possible to promptly start displaying the second content CT2 after the start of a new specific event, and to display the second content CT2 more quickly. <Aspect rules>

[0083] When the display range of the virtual image is made switchable, display problems such as display annoyance or attention that are specific to the switching of the display range may occur. When such problems occur, the convenience for the occupants may be impaired. Therefore, when the display range of the image is made switchable, it is required to reduce the display annoyance or attention that are specific to the switching of the display range.

[0084] Therefore, in the above-mentioned display control process, if the position of the selected display area VA is not the normal position VP1, it is preferable to display the virtual image Vi to which the aspect rule is applied. The aspect rule is a rule that is linked to at least one of the type of content CT and the position of the display area VA. The cases where the position of the display area VA is not the normal position VP1 include the case where the display area VA is at the upper position VP2 or the case where the display area VA is moving.

[0085] The display control unit 73 can display the content CT in an expression method that is less bothersome or less eye-catching by applying the aspect rule to the virtual image Vi. In this embodiment, it is assumed that a lookup table and graphic data corresponding to a plurality of pre-set aspect rules are prepared in the data storage unit 72. The display control unit 73 can display the virtual image Vi to which the aspect rule is appropriately applied by referring to the lookup table and the graphic data. Details of the plurality of types of aspect rules used in this embodiment will be described in order below. Note that a combination of a plurality of aspect rules may be applied, or only some of the aspect rules may be applied. When a plurality of aspect rules are combined, combinations that result in mutually contradictory aspects may be excluded.

[0086] <First aspect rule> The first aspect rule is a aspect rule associated with the upper position VP2. The first aspect rule is applied to the virtual image Vi displayed at the upper position VP2. By applying the first aspect rule, the aspect of the virtual image Vi displayed at the upper position VP2 is more limited than the aspect of the virtual image Vi displayed at the normal position VP1. As a result, the virtual image Vi displayed at the upper position VP2 is less likely to be a distraction to the driver.

[0087] [Limits on text information] The display control unit 73 applies the first aspect rule to the text information MJ (see FIG. 10) displayed at the upper position VP2. The text information MJ includes an image portion that changes in real time to indicate the vehicle speed, street name, etc., as well as an image portion that notifies the user of an application in operation, etc. By applying the first aspect rule, the text information MJ displayed at the upper position VP2 is limited in at least one of the number of characters and the character size compared to the text information MJ displayed at the normal position VP1. The display control unit 73 of this embodiment limits both the number of characters and the character size of the text information MJ at the upper position VP2. As a result, the amount of information of the text information MJ at the upper position VP2 is made smaller than that at the normal position VP1. The amount of information may be rephrased as volume.

[0088] Specifically, no limit is set on the number of characters for the character information MJ displayed at the normal position VP1. On the other hand, a limit is applied to the number of characters for the character information MJ displayed at the upper position VP2, such as less than 10 characters, or the number of characters that can be written in one line. Furthermore, for example, only a lower limit of character size is set for the character information MJ displayed at the normal position VP1. On the other hand, both a lower limit and an upper limit of character size are set for the character information MJ displayed at the upper position VP2. The lower limit of character size at the upper position VP2 is set larger than the lower limit of character size at the normal position VP1. The upper limit of character size is specified, for example, by the ratio to each of the vertical and horizontal sizes of the display area VA. Furthermore, at the upper position VP2, the spacing between characters is secured to be wider than at the normal position VP1.

[0089] According to the above configuration, the character information MJ is limited in at least one of the number of characters and the character size compared to when it is displayed at the normal position VP1. This makes it possible to avoid a situation in which the character information MJ, which takes time to read, is displayed near the central visual field CVF and causes a distraction.

[0090] [Background fill limit] The display control unit 73 applies the first aspect rule to the filled-in background NH (see FIG. 10) displayed at the upper position VP2. The text information MJ is displayed superimposed on the filled-in background NH. The filled-in background NH is an image portion that emphasizes the text information MJ, and is drawn in a display color different from that of the text information MJ. As an example, the filled-in background NH is a chromatic, highly luminous display color. In this case, the display color may be, for example, red. On the other hand, the text information MJ is an achromatic, highly luminous display color. In this case, the display color may be, for example, white.

[0091] When the display control unit 73 displays the text information MJ at the upper position VP2 superimposed on the filled-in background NH, it emphasizes the outline Ri of the characters included in the text information MJ by outlining them in a color different from that of the filled-in background NH. The outline Ri is, for example, an achromatic, low-brightness display color. The outline Ri creates a visual effect that increases the light-dark contrast between the filled-in background NH and the text information MJ. As a result, the readability of the text information MJ can be improved.

[0092] The display control unit 73 limits the duration of display of the filled-in background NH by applying the first aspect rule to the filled-in background NH displayed at the upper position VP2 (see FIG. 11). Specifically, the display control unit 73 limits the duration of display of the filled-in background NH to a very short time. This time may be, for example, about 0.1 seconds. The display control unit 73 prompts the driver to notice by displaying the filled-in background NH for a short time. Thereafter, the display control unit 73 ends the display of the filled-in background NH so that the wide-area filled-in background NH does not block the driver's field of vision. While continuing to display the text information MJ, the display control unit 73 displays a frame-shaped image WK (see the lower part of FIG. 11) on both the left and right sides of the text information MJ in place of the filled-in background NH. The frame-shaped image WK is drawn in a line shape in the same display color as the filled-in background NH so as not to block the driver's forward field of vision.

[0093] According to the above configuration, the display duration of the filled-in background NH is limited. Therefore, it is difficult for a wide area to be filled in and block the driver's field of vision for a long period of time. In addition, the provision of the contour Ri as described above improves the readability of the text information MJ. As a result, even if the text information MJ is displayed near the central visual field CVF, excessive attention is unlikely to be generated.

[0094] <Second mode rule> The second aspect rule is a aspect rule associated with the moving display area VA. The second aspect rule is applied to the virtual image Vi when the displacement mechanism 63 moves the display area VA from the normal position VP1 to the upper position VP2. Application of the second aspect rule suppresses the attraction during the movement of the display area VA and the optical illusion before and after the movement of the display area VA.

[0095] [Display Limits While Moving] When the displacement mechanism 63 moves the display area VA from the normal position VP1 to the upper position VP2, the display control unit 73 applies the second aspect rule as follows. The display control unit 73 hides the virtual image Vi that was displayed at the normal position VP1 before the movement of the display area VA starts. As an example, when the vehicle speed CTv and the route guidance content CTrg are displayed at the normal position VP1 as the first content CT1, the display control unit 73 performs the following. After hiding these virtual images Vi, the display control unit 73 starts the movement of the display area VA by the displacement mechanism 63 (see FIG. 12). After the display area VA moves to the upper position VP2, the display control unit 73 redisplays the vehicle speed CTv and the route guidance content CTrg.

[0096] The display control unit 73 may do the same when the displacement mechanism 63 moves the display area VA from the upper position VP2 to the normal position VP1. That is, the display control unit 73 may hide the virtual image Vi that was displayed at the upper position VP2 before the display area VA starts to move. In this case, too, the display control unit 73 redisplays the content CT that was once hidden after the display area VA moves to the normal position VP1. With the above configuration, it is less likely that the virtual image Vi displayed when the display area VA moves will attract the driver's attention and cause discomfort.

[0097] [Size adjustment in perspective direction] When displaying the content CT common before and after the movement from the normal position VP1 to the upper position VP2, the display control unit 73 applies the second aspect rule as follows. The display control unit 73 adjusts the display size of the virtual image Vi so that the relationship with the vanishing point VNP in the foreground is maintained. As an example, when the first content CT1 including the bar-shaped image portion Phb extending along the horizontal direction is displayed at the normal position VP1, the display control unit 73 may perform the following. The display control unit 73 may reduce the bar-shaped image portion Phb in the perspective direction and display it at the upper position VP2 (see FIG. 13). The bar-shaped image portion Phb is included in the content CT indicating, for example, the operation of the ACC, and is displayed as an image portion indicating the vehicle ahead. The horizontal direction corresponds to the left-right direction Yo in FIG. 13.

[0098] If a bar-shaped image portion Phb with the same display size as that at the normal position VP1 is displayed at the upper position VP2, the bar-shaped image portion Phb will be enlarged relative to the foreground. This display mode of the bar-shaped image portion Phb may cause unintended emphasis of the foreground. Therefore, the display control unit 73 adjusts the size of the bar-shaped image portion Phb displayed at the upper position VP2 to be smaller, according to the perspective reference lines PL that converge at the vanishing point VNP. By adjusting the display size in this way, unintended emphasis due to the Pongee illusion is avoided.

[0099] [Tilt adjustment taking vanishing point into account] The display control unit 73 applies the second aspect rule to the line-shaped image portion PbL extending toward the vanishing point VNP in the foreground. This second rule is applied when the content CT including the line-shaped image portion PbL is displayed before and after the content CT moves from the normal position VP1 to the upper position VP2. The display control unit 73 adjusts the inclination of the line-shaped image portion PbL so that the orientation toward the vanishing point VNP is maintained (see FIG. 14). As an example, the line-shaped image portion PbL is an image portion that emphasizes the lane markings of the vehicle in each of the first content CT1 and the second content CT2 (see also FIG. 21).

[0100] The display control unit 73 adjusts the inclination of the line-shaped image portion PbL according to the position of the display area VA, in accordance with the perspective reference lines PL that converge at the vanishing point VNP. As a result, the line-shaped image portion PbL of the first content CT1 is displayed in a more vertical orientation than the line-shaped image portion PbL of the second content CT2. In other words, the line-shaped image portion PbL of the second content CT2 is displayed in a more horizontal orientation than the line-shaped image portion PbL of the first content CT1. This makes it less likely that a situation will occur in which a deviation in the orientation of the line-shaped image portion PbL relative to a dividing line or the like in the foreground causes a sense of incongruity.

[0101] 13 and 14 are virtual lines used for explanation and are not actually displayed. Also, the size adjustment in the perspective direction and the tilt adjustment taking into account the vanishing point VNP are aspect rules that are linked to the type of content CT as well as the position of the display area VA.

[0102] <Third aspect rule> The third aspect rule is a aspect rule linked to both the type of content CT and the position of the display area VA. The third aspect rule is applied to the second content CT2 displayed in the display area VA at the upper position VP2. The third aspect rule is a rule that does not point to a specific object in the foreground. As described above, the second content CT2 of this embodiment is not an AR display object, and does not specify a superimposed object. Therefore, if the second content CT2 is made to point to a specific object in the foreground, there is a risk that the driver will have a wrong perception. According to the third aspect rule, such a wrong perception by the driver is suppressed.

[0103] When the display control unit 73 displays the second content CT2 at the upper position VP2, the display control unit 73 may do the following by applying the third aspect rule. The display control unit 73 may avoid, for example, displaying the second content CT2 superimposed on a specific object in the foreground. An example of the specific object is a lane marking. As an example, a case will be described in which the content CT indicating the operation of the LDW is displayed as the second content CT2 including the line-shaped image portion PbL (see FIG. 15). In this case, the display control unit 73 superimposes and displays the line-shaped image portion PbL inside the lane marking so that the line-shaped image portion PbL does not overlap with the lane marking in the foreground. This suppresses excessive attention to the lane marking and suppresses the driver from being motivated to unintentionally match the line-shaped image portion PbL with the lane marking.

[0104] The following can be mentioned as a mode for suppressing the driver's motivation to match the line-shaped image portion PbL with the marking line. For example, as shown in Fig. 15, the inclination of the line-shaped image portion PbL may be set to a value that does not match the inclination of the marking line. This also makes it possible to suppress the driver's motivation to match the line-shaped image portion PbL with the marking line.

[0105] <Fourth aspect rule> The fourth aspect rule is a aspect rule that is linked to both the type of content CT and the position of the display area VA. The fourth aspect rule aims to reduce the cognitive load of the content CT and shorten the time it takes the driver to recognize, judge, and operate. The fourth aspect rule is applied to a specific type of content CT that is displayed in the display area VA at the upper position VP2. By applying the fourth aspect rule, the virtual image Vi is displayed in an expression that takes into consideration correct perception, intuitive understanding, and understanding of the relationship with outside-vehicle information.

[0106] [Automatic Brake Content] The display control unit 73 applies the fourth aspect rule when displaying the automatic braking content CTpc shown in Figures 10 and 11 at the upper position VP2. The fourth aspect rule is applied to the automatic braking content CTpc. The automatic braking content CTpc is content CT that notifies the driver of the operation of the PCS by the driving assistance ECU 22 (see Figure 2). The PCS may also be referred to as Autonomous Emergency Braking. The display control unit 73 displays a virtual image Vi formed by superimposing text information MJ of "BRAKE" on a solid background NH as the automatic braking content CTpc in the display area VA at the upper position VP2.

[0107] The display control unit 73 applies a fourth aspect rule including the above-mentioned first aspect rule to the automatic braking content CTpc. In detail, when displaying the automatic braking content CTpc, the display control unit 73 imparts visual effects such as blinking and enlargement to the virtual image Vi (see the upper part of FIG. 11). This is to allow the driver to notice the warning as soon as possible.

[0108] In addition, the display control unit 73 gives each character of the text information MJ a dark outline Ri and limits the number and size of characters in the text information MJ. This improves readability of the text information MJ (see FIG. 10 and the middle part of FIG. 11). After encouraging the driver to notice, the display control unit 73 performs the following so as not to block the driver's forward visibility: The display control unit 73 ends the display of the filled-in background NH and switches to the display of a frame-shaped image WK (see the lower part of FIG. 11).

[0109] [Route Guidance Content] When displaying the route guidance content CTrg shown in Figs. 16 to 19 at the upper position VP2, the display control unit 73 applies the fourth aspect rule to the route guidance content CTrg. The route guidance content CTrg is a so-called turn-by-turn display. The route guidance content CTrg is displayed based on route information provided by the navigation ECU 21, and is used for route guidance at guidance points. Specifically, the route guidance content CTrg guides the driver to the locations of the destination and intermediate points, the directions to turn right and left, branching points and merging points, etc.

[0110] The route guidance content CTrg displayed at the upper position VP2 is composed of an arrow image section PgA, a road surface marking section Prm, a remaining distance meter Pdm, and the like. The arrow image section PgA includes a plurality of arrow-shaped image elements arranged in the left-right direction Yo. The arrow image section PgA indicates the travel direction of the vehicle at the guidance point by each image element. An example of the guidance point is an intersection. In the example of FIG. 16, the travel direction of the vehicle is to the right. The road surface marking section Prm is disposed below the arrow image section PgA. The road surface marking section Prm is drawn in an L-shape and superimposed on the road surface ahead to guide the vehicle along the planned route at the guidance point. In the example of FIG. 16, the planned route is a right turn. The remaining distance meter Pdm indicates the remaining distance to the guidance point as a numerical value based on the route information.

[0111] The display control unit 73 moves the display area VA from the normal position VP1 (see FIG. 12) to the upper position VP2 just before the remaining distance to the guide point becomes approximately 100 m. If the route guidance content CTrg (see FIG. 12) is displayed at the normal position VP1, the display control unit 73 performs the following. In accordance with the first aspect rule, the display control unit 73 hides the route guidance content CTrg before the movement of the display area VA begins. The display control unit 73 may fade out the route guidance content CTrg towards the guide point. The route guidance content CTrg may fade out towards the vanishing point VNP as shown in FIG. 13.

[0112] The display control unit 73 displays the route guidance content CTrg in the display area VA that has been moved to the upper position VP2 (see the upper part of FIG. 16). The display control unit 73 applies the fourth behavior rule to the route guidance content CTrg as follows. The display control unit 73 limits changes in the behavior of the route guidance content CTrg until the remaining distance from the vehicle Am to the guidance point falls below a predetermined value. As an example, the display control unit 73 fixes the behavior of the route guidance content CTrg until the remaining distance falls below 50 m. Then, when the remaining distance falls below 50 m, the display control unit 73 changes the behavior of the route guidance content CTrg depending on the remaining distance from the vehicle Am to the guidance point.

[0113] The display control unit 73 fixes the value of the remaining distance meter Pdm at the initial value of "100 m" until the remaining distance becomes less than 50 m. Then, when the remaining distance becomes 50 m, the display control unit 73 changes the value of the remaining distance meter Pdm from "100 m" to "50 m" (see the lower part of FIG. 16). After this, the display control unit 73 continuously decreases the value of the remaining distance meter Pdm until the vehicle Am reaches the guidance point (see FIG. 17 and FIG. 18). Then, after the vehicle Am reaches the guidance point, the display control unit 73 continues to display the remaining distance meter Pdm indicating the value of "0 m" until the end of the route guidance (see FIG. 19).

[0114] Furthermore, the display control unit 73 does not change the display color and shape of the arrow image unit PgA and the road marking unit Prm until the remaining distance becomes less than 50 m. When the remaining distance becomes less than 50 m, the display control unit 73 performs the following: The display control unit 73 starts an animation display in which the display color of each image element of the arrow image unit PgA changes in sequence in the direction in which the vehicle Am is turning right or left (see Figs. 17 and 18). The display control unit 73 continues the animation display of the arrow image unit PgA until the vehicle Am has finished turning right or left (see Fig. 19).

[0115] Furthermore, the display control unit 73 starts changing the appearance of the route guidance content CTrg when the remaining distance becomes less than 50 m. The display control unit 73 changes at least one of the display position and the display color of the route guidance content CTrg, or displays it as an animation. In this way, the display control unit 73 helps the driver understand the remaining distance. Specifically, the display control unit 73 may do the following when the remaining distance becomes less than 50 m. The display control unit 73 changes the display color of the road marking part Prm from an achromatic color to a chromatic color that is the same as or similar to the arrow image part PgA (see FIG. 17). An example of an achromatic color is gray. An example of a chromatic color is blue or light blue. Furthermore, the display control unit 73 continuously changes the shape of the road marking part Prm in accordance with the approach of the vehicle Am to the guidance point (see FIG. 17 to FIG. 19).

[0116] The above-mentioned route guidance content CTrg can visually show the sense of distance to the guide point by transitioning from a state in which behavioral changes are restricted to a state in which behavioral changes are utilized. Furthermore, the timing of right and left turns, etc., is clearly shown to the driver by animation display of the arrow image portion PgA, etc. In addition, since all virtual images Vi are erased when the display area VA moves, the annoyance caused by switching the display area VA is reduced. This allows the route guidance content CTrg to appropriately assist in grasping the remaining distance to the guide point. As a result, the driver can receive appropriate guidance and pass the guide point.

[0117] [FCTA Content] When displaying the FCTA content CTta shown in Fig. 20 at the upper position VP2, the display control unit 73 applies the fourth aspect rule to the FCTA content CTta. The FCTA content CTta is notification content that notifies other vehicles approaching from the front left and right among risk objects around the vehicle Am. These other vehicles are hereinafter referred to as approaching vehicles Av. The FCTA content CTta is displayed based on the recognition of the approaching vehicle Av by the driving assistance ECU 22, for example, in a scene in which the vehicle enters an intersection.

[0118] The FCTA content CTta is displayed on the side of the display area VA in the left-right direction Yo where the approaching vehicle Av is present. Specifically, when the approaching vehicle Av is approaching from the left side of the host vehicle, the FCTA content CTta is displayed in an area to the left of the center of the display area VA (see FIG. 20). On the other hand, when the approaching vehicle Av is approaching from the right side of the host vehicle, the FCTA content CTta is displayed in an area to the right of the center of the display area VA.

[0119] When the display control unit 73 displays the FCTA content CTta at the upper position VP2, the display control unit 73 may do as follows by applying the fourth aspect rule. The display control unit 73 sets a non-display area ANP in which the virtual image Vi is not displayed within the display area VA that has moved from the normal position VP1 to the upper position VP2. When the approaching vehicle Av is approaching from the left side of the vehicle, the display control unit 73 sets the area to the right of the center of the display area VA as the non-display area ANP (see FIG. 20). On the other hand, when the approaching vehicle Av is approaching from the right side of the vehicle, the display control unit 73 sets the area to the left of the center of the display area VA as the non-display area ANP. By setting the non-display area ANP in this way, the visibility of the FCTA content CTta that notifies the risk object is less likely to be obstructed by other virtual images Vi. As a result, the driver can quickly grasp the type and relative position of the risk object.

[0120] In addition, the display control unit 73 limits the number of display colors available for the virtual image Vi by applying the fourth aspect rule. Furthermore, the display control unit 73 displays the FCTA content CTta in a manner that allows it to be distinguished from the route guidance content CTrg by its display color and shape. Specifically, the display control unit 73 displays the route guidance content CTrg in a display color such as blue or light blue. On the other hand, the display control unit 73 displays the FCTA content CTta in a display color such as yellow or amber. Such a restriction on the display colors can assist the driver in instantaneous understanding of information.

[0121] The approaching vehicle warning icon PaC is, for example, an image portion in which a symbol "!" is surrounded by a triangular frame, and alerts the driver to the presence of an approaching vehicle Av. The approaching vehicle warning icon PaC is drawn in an oblique position that becomes deeper toward the center by rotating around an axis along the vertical direction US. The approaching vehicle warning icon PaC is displayed superimposed on the plane arrow image portion PaR.

[0122] The surface arrow image section PaR has a shape extending in a band shape along the left-right direction Yo. The surface arrow image section PaR employs a gradation expression in the left-right direction Yo. The surface arrow image section PaR is drawn with high saturation and high brightness on the side closer to the approaching vehicle Av in the left-right direction Yo. In the example of FIG. 20, the surface arrow image section PaR is drawn with high saturation and high brightness on the left side in the left-right direction Yo. Furthermore, the surface arrow image section PaR emphasizes the relative position of the approaching vehicle Av to the driver by displaying an animation that flows starting from the side closer to the approaching vehicle Av.

[0123] As described above, the plane arrow image section PaR employs an expression that combines a plane arrow shape with a gradation expression. This allows it to be clearly distinguished from the arrow image section PgA of the route guidance content CTrg. In addition, the approaching vehicle warning icon PaC superimposed on the plane arrow image section PaR instantly informs the driver that it is a warning. Therefore, the FCTA content CTta is less likely to be mistaken for the route guidance content CTrg.

[0124] [Avoidance support content] 21 at the upper position VP2, the display control unit 73 applies the fourth aspect rule to the avoidance support content CTas. The avoidance support content CTas is notification content that notifies pedestrians PE, cyclists, etc. approaching from the front left and right of risk objects around the vehicle Am. The avoidance support content CTas is displayed when the driving support ECU 22 performs steering support control or deceleration support control to avoid pedestrians PE, etc.

[0125] The avoidance assistance content CTas is displayed on the side of the display area VA in the left-right direction Yo where the pedestrian PE, etc. are present. Specifically, when the pedestrian PE is approaching from the left side of the host vehicle, the avoidance assistance content CTas is displayed in an area to the left of the center of the display area VA (see FIG. 21). On the other hand, when the pedestrian PE is approaching from the right side of the host vehicle, the avoidance assistance content CTas is displayed in an area to the right of the center of the display area VA.

[0126] When displaying the avoidance support content CTas at the upper position VP2, the display control unit 73 applies the fourth aspect rule as follows. The display control unit 73 sets a non-display area ANP in the display area VA that has moved to the upper position VP2. When a pedestrian PE or the like is approaching from the left side of the vehicle, the display control unit 73 sets the area to the right of the center of the display area VA as the non-display area ANP (see FIG. 21). On the other hand, when a pedestrian PE or the like is approaching from the right side of the vehicle, the display control unit 73 sets the area to the left of the center of the display area VA as the non-display area ANP. By setting the non-display area ANP in this way, the visibility of the avoidance support content CTas that notifies the risk object is less likely to be obstructed by other virtual images Vi. As a result, the driver can quickly grasp the type and relative position of the risk object.

[0127] Furthermore, the display control unit 73 applies the fourth aspect rule to limit the number of display colors available for the virtual image Vi after the display area VA moves from the normal position VP1 to the upper position VP2. As an example, the display control unit 73 displays the avoidance support content CTas, which is composed of the pedestrian warning icon PaP and the line-shaped image portion PbL, in a single color. For example, the avoidance support content CTas may be displayed in a single color such as yellow or amber. Such a restriction on the display colors can assist the driver in instantaneous understanding of information.

[0128] The pedestrian warning icon PaP is an image portion in which an icon resembling a pedestrian PE is surrounded by a triangular frame, and alerts the driver to the presence of the pedestrian PE. The pedestrian warning icon PaP indicates the direction of movement of the pedestrian PE with a minimum of elements. As an example, the minimum elements are the dynamic pose of the hands and feet drawn on the icon, and the drawing of the icon in a diagonal posture that becomes deeper as it approaches the center.

[0129] The line-shaped image portion PbL is an image portion that extends toward the vanishing point VNP (see FIG. 14) in the foreground. The line-shaped image portion PbL is disposed so as to be in contact with the end portion on the lower center side of the pedestrian warning icon PaP, and together with the pedestrian warning icon PaP, it emphasizes and indicates to the driver the relative position of the pedestrian PE.

[0130] As described above, the display control unit 73 makes it easier for the driver to recognize the pedestrian PE by displaying the avoidance support content CTas in a large, easily visible manner. Furthermore, the avoidance support content CTas can instantly inform the driver of the left and right directions in which the pedestrian PE is approaching. This can be achieved by setting the non-display area ANP and the pedestrian warning icon PaP that is displayed in a single color at an angle.

[0131] (Other embodiments) Although one embodiment of the present disclosure has been described above, the present disclosure is not to be construed as being limited to the above embodiment. The present disclosure can be applied to various embodiments and combinations within the scope of the gist of the present disclosure.

[0132] In the first modification, the display of the text information MJ such as the vehicle speed and street name in the upper position VP2 is restricted. Specifically, the text information MJ, whose contents change in real time, is not displayed in the display area VA in the upper position VP2. Furthermore, in the first modification, the filled-in background NH is not displayed in the display area VA in the upper position VP2.

[0133] The displacement mechanism 63 of the second modification can displace the display area VA not only in the up-down direction US but also in the left-right direction Yo. Furthermore, the displacement mechanism 63 may position the display area VA at a position different from the normal position VP1 and the upper position VP2. Furthermore, the displacement mechanism 63 may 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 may displace the housing of the HUD 100 relative to the vehicle Am.

[0134] In the third modification, real-time detection information of the eye point EP by the indoor camera is provided to the head-up ECU 70. The indoor camera is a camera that captures the interior of the vehicle Am. The display control unit 73 adjusts each position of the display area VA and the display position of the virtual image Vi according to the current position of the eye point EP based on the detection information in cooperation with the indoor camera.

[0135] The content CT to which each aspect rule is applied is not limited to the above-mentioned content. Each aspect rule can be applied to various contents CT that can be displayed by the HUD 100. For example, each aspect rule can be applied to ACC content, LTC content, RSA (Road Sign Assist) content, narrow road driving support content, etc.

[0136] In addition, the shape, luminous color, display position, etc. of the image of each content may be changeable according to the driver's preference. Also, the driver may select whether to apply each aspect rule. For example, the number of colors, the number of characters, the character size, etc. permitted to be displayed at the upper position VP2 may be adjustable. Furthermore, the type of language and unit included in the text information MJ may be appropriately changed based on the user settings of the driver, etc., and the settings of the country and region where the vehicle Am is used, etc.

[0137] In the fourth modification, a part or all of the processing functions of the head-up ECU 70 are implemented in the meter ECU 32 or another in-vehicle ECU. In the fourth modification, a system including the meter ECU 32 or another in-vehicle ECU corresponds to the virtual image display device.

[0138] In the fifth modification, a part or all of the processing functions of the head-up ECU 70 are implemented in an integrated control device such as an HCU (Human Machine Interface Control Unit). The processing functions of the meter ECU 32 may be further integrated in such an HCU. In the fifth modification, the system including the HUD 100 and the HCU corresponds to a virtual image display device.

[0139] The PGU 61 may be provided with an EL (Electro Luminescence) panel instead of the LCD panel and backlight. Also, instead of the EL panel, the PGU 61 may be provided with a display such as a plasma display panel, a cathode ray tube, or an LED. Furthermore, instead of the LCD panel and backlight, a laser projector or DLP (Digital Light Processing, registered trademark) and a screen may be provided. In the PGU 61 employing such a configuration, a display image drawn on the screen is projected onto the windshield WS by the magnifying optical system 62 and formed as a virtual image Vi. In addition, the optical element employed in the magnifying optical system 62 is not limited to the concave mirror 62a, and may be appropriately changed to various mirrors, lenses, holographic optical elements, etc.

[0140] The processing units provided in the head-up ECU 70 and the meter ECU 32 are hardware for arithmetic processing coupled with a RAM. The processing units include at least one arithmetic core such as a central processing unit (CPU) and a graphics processing unit (GPU). The processing units may further include, for example, a field-programmable gate array (FPGA) and an IP core having other dedicated functions. Meanwhile, the RAM may include a video RAM for image generation. The processing units access the RAM to execute various processes for realizing the virtual image display method of the present disclosure.

[0141] The storage includes a non-volatile storage medium (non-transitory tangible storage medium). The storage of each ECU 32, 70 stores various programs executed by the processing unit. The programs are, for example, a display control program. Such a storage medium is not limited to being provided on a circuit board, and may be provided in the form of a memory card or the like, inserted into a slot, and electrically connected to the control circuit of each ECU 32, 70. Furthermore, the storage medium may be an optical disk, a hard disk drive, or the like from which the programs are copied or distributed to each ECU 32, 70.

[0142] The functions provided by the head-up ECU 70 and the meter ECU 32 can be provided by software and hardware that executes the software, software alone, hardware alone, or a combination of these. Furthermore, when such functions are provided by electronic circuits as hardware, the functions can be provided by digital circuits including many logic circuits, or analog circuits.

[0143] The vehicle equipped with the display system 1 is not limited to a general private passenger car. The vehicle equipped with the display system 1 may be a rental car vehicle, a manned taxi vehicle, a ride-sharing vehicle, a freight vehicle, a bus, etc. The vehicle equipped with the display system 1 may be a right-hand drive vehicle or a left-hand drive vehicle. Furthermore, the traffic environment in which the vehicle travels may be a traffic environment premised on left-hand traffic or a traffic environment premised on right-hand traffic. The display control according to the present disclosure may be appropriately optimized according to the road traffic laws of each country and region, and further the steering wheel position of the vehicle, etc.

[0144] The control unit and the method described herein may be implemented by a special-purpose computer having a processor programmed to execute one or more functions embodied in a computer program. Alternatively, the device and the method described herein may be implemented by a special-purpose hardware logic circuit. Alternatively, the device and the method described herein may be implemented by one or more special-purpose computers configured by a combination of a processor that executes a computer program and one or more hardware logic circuits. The computer program may also be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by the computer.

[0145] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple dependent claims. Some of the claims may be described in a multiple dependent form, where the subsequent claim alternatively refers to the preceding claim. Furthermore, some of the claims may be described in a multiple dependent form, where the subsequent claim alternatively refers to the preceding claim. The claims described in these multiple dependent forms define multiple technical ideas.

[0146] (Technical thought 1) A virtual image display device that displays a virtual image visible to a driver of a vehicle, a switching mechanism (63) that switches a position of a display area where the virtual image is displayed between a plurality of positions including a first position and a second position; a display control unit (73) that displays the virtual images of a first content, which is a type of content to be displayed at the first position, and a second content, which is a type of content to be displayed at the second position, in response to switching of the position of the display area by the switching mechanism; an event status identification unit (74) that identifies a status of a specific event that is an event that requires the second content to be displayed; the switching mechanism switches the display area to the second position when the event status identification unit identifies that the specific event has occurred and when the position of the display area is not the second position; The display control unit is a virtual image display device that displays the second content before the switching mechanism completes switching of the display area to the second position when the event status identification unit identifies that the specific event has occurred and the position of the display area is not the second position.

[0147] (Technical thought 2) A virtual image display device according to Technical Concept 1, the switching mechanism switches the display area from the first position to the second position when the event status identification unit identifies that the specific event has occurred and when the position of the display area is the first position; The display control unit is a virtual image display device that, when the event status identification unit identifies that the specific event has occurred and the position of the display area is the first position, displays the second content from the time when the display area is located at the first position before the switching mechanism completes switching of the display area from the first position to the second position.

[0148] (Technical Thought 3) A virtual image display device according to Technical Concept 1 or 2, the switching mechanism switches the display area to the first position when an end of all of the specific events whose starts have been identified by the event status identification unit has been identified; The virtual image display device, when the display control unit has identified the end of all of the specific events whose starts have been identified by the event status identification unit, ends the display of the second content before the switching mechanism completes switching of the display area to the first position, and displays a transition content that includes at least a portion of the first content.

[0149] (Technical Thought 4) A virtual image display device according to Technical Concept 3, the switching mechanism switches the display area from the second position to the first position when an end of all of the specific events whose starts have been identified by the event status identification unit has been identified and the position of the display area is at the second position; The display control unit, when the end of all of the specific events whose starts have been identified by the event status identification unit has been identified and the position of the display area is at the second position, ends the display of the second content and displays the transition content from the time when the display area is at the second position before the switching mechanism completes switching of the display area from the second position to the first position.

[0150] (Technical Thought 5) A virtual image display device according to any one of Technical Ideas 1 to 4, a situation type specifying unit (75) for specifying a situation type that is either a situation type of the occurrence of the specific event or a situation type of the end of the specific event; the switching mechanism switches the display area at a timing according to the situation type identified by the situation type identification unit; The display control unit switches the content to be displayed at a timing according to the situation type identified by the situation type identification unit.

[0151] (Technical Thought 6) A virtual image display device according to Technical Concept 5, the situation type identification unit identifies, as the situation type, at least a first situation type in which, when the specific event is occurring and the position of the display area is at the second position, a new specific event has occurred, the new specific event having a set priority higher than that of the specific event; when the situation type identification unit identifies the first situation type, the switching mechanism maintains the position of the display area at the second position without switching the position from the second position to the first position; When the first situation type is identified by the situation type identification unit, the display control unit starts displaying the second content for the new specific event from the timing at which the first situation type is identified, and displays the second content for the new specific event.

[0152] (Technical Thought 7) A virtual image display device according to Technical Idea 5 or 6, the situation type identification unit identifies, as the situation type, at least a second situation type in which the specific event ends while the switching mechanism is switching the position of the display area to the second position due to the occurrence of the specific event; when the second situation type is identified by the situation type identification unit, the switching mechanism changes the position of the display area to the first position even if the position of the display area has not been switched to the second position, When the second situation type is identified by the situation type identification unit, the display control unit starts to end the display of the second content from the timing at which the second situation type is identified, thereby ending the display of the second content, and starts to display a transition content, which is content including at least a portion of the first content, thereby displaying the transition content.

[0153] (Technical Thought 8) A virtual image display device according to any one of Technical Ideas 5 to 7, the situation type identification unit identifies, as the situation type, at least a third situation type in which, while the specific event is occurring and the switching mechanism is switching the position of the display area to the second position, a new specific event has occurred, the new specific event having a set priority higher than that of the specific event; when the situation type identification unit identifies the third situation type, the switching mechanism continues to switch the position of the display area to the second position without temporarily switching the position of the display area from the second position to the first position; When the third situation type is identified by the situation type identification unit, the display control unit starts displaying the second content for the new specific event from the timing at which the third situation type is identified, and displays the second content for the new specific event.

[0154] (Technical Thought 9) A virtual image display device according to any one of Technical Ideas 5 to 8, the situation type identification unit identifies, as the situation type, at least a fourth situation type in which a new specific event has occurred while the switching mechanism is switching the position of the display area to the first position due to an end of the specific event; when the fourth situation type is identified by the situation type identification unit, the switching mechanism changes the position of the display area to the second position even if the position of the display area has not been switched to the first position, When the fourth situation type is identified by the situation type identification unit, the display control unit starts displaying the second content for the new specific event from the timing at which the fourth situation type is identified, and displays the second content for the new specific event. [Explanation of symbols]

[0155] VP1 normal position (first position), VP2 upper position (second position), 63 displacement mechanism (switching mechanism), 73 display control unit, 74 event situation identification unit, 75 situation type identification unit, 100 HUD (HUD)

Claims

1. A virtual image display device that displays a virtual image visible to a driver of a vehicle, A switching mechanism (63) that switches a position of a display area where the virtual image is displayed between a plurality of positions including a first position and a second position; a display control unit (73) that displays the virtual images of a first content, which is a type of content to be displayed at the first position, and a second content, which is a type of content to be displayed at the second position, in response to switching of the position of the display area by the switching mechanism; an event status specification unit (74) that specifies a status of a specific event that is an event that requires the second content to be displayed; the switching mechanism switches the display area to the second position when the event status identification unit identifies that the specific event has occurred and when the position of the display area is not the second position; The display control unit is a virtual image display device that displays the second content before the switching mechanism completes switching of the display area to the second position when the event status identification unit identifies that the specific event has occurred and the position of the display area is not the second position.

2. The virtual image display device according to claim 1 , the switching mechanism switches the display area from the first position to the second position when the event status identification unit identifies that the specific event has occurred and when the position of the display area is the first position; The display control unit is a virtual image display device that, when the event status identification unit identifies that the specific event has occurred and the position of the display area is the first position, displays the second content from the time when the display area is located at the first position before the switching mechanism completes switching of the display area from the first position to the second position.

3. The virtual image display device according to claim 1 , the switching mechanism switches the display area to the first position when an end of all of the specific events whose starts have been identified by the event status identification unit has been identified; When the display control unit has identified the end of all of the specific events whose starts have been identified by the event status identification unit, the virtual image display device terminates the display of the second content before the switching mechanism has completed switching of the display area to the first position, and displays a transition content that includes at least a portion of the first content.

4. The virtual image display device according to claim 3, the switching mechanism switches the display area from the second position to the first position when an end of all of the specific events whose starts have been identified by the event status identification unit has been identified and the position of the display area is at the second position; When the display control unit has identified the end of all of the specific events whose starts have been identified by the event status identification unit and the position of the display area is the second position, the virtual image display device ends the display of the second content and displays the transition content from the time when the display area is located at the second position before the switching mechanism completes switching of the display area from the second position to the first position.

5. The virtual image display device according to claim 1 , a situation type specifying unit (75) for specifying a situation type which is either a situation type of the occurrence of the specific event or a situation type of the end of the specific event; the switching mechanism switches the display area at a timing according to the situation type identified by the situation type identification unit; The display control unit switches the content to be displayed at a timing according to the situation type identified by the situation type identification unit.

6. The virtual image display device according to claim 5 , the situation type identification unit identifies, as the situation type, at least a first situation type in which, when the specific event is occurring and the position of the display area is at the second position, a new specific event has occurred, the new specific event having a set priority higher than that of the specific event; when the situation type identification unit identifies the first situation type, the switching mechanism maintains the position of the display area at the second position without switching the position from the second position to the first position; When the first situation type is identified by the situation type identification unit, the display control unit starts displaying the second content for the new specific event from the timing at which the first situation type is identified, and displays the second content for the new specific event.

7. The virtual image display device according to claim 5 , the situation type identification unit identifies, as the situation type, at least a second situation type in which the specific event ends while the switching mechanism is switching the position of the display area to the second position due to the occurrence of the specific event; when the second situation type is identified by the situation type identification unit, the switching mechanism changes the position of the display area to the first position even if the position of the display area has not been switched to the second position, When the second situation type is identified by the situation type identification unit, the display control unit starts to end the display of the second content from the timing at which the second situation type is identified, thereby ending the display of the second content, and starts to display a transition content, which is content including at least a portion of the first content, thereby displaying the transition content.

8. The virtual image display device according to claim 5 , the situation type identification unit identifies, as the situation type, at least a third situation type in which, while the specific event is occurring and the switching mechanism is switching the position of the display area to the second position, a new specific event has occurred, the new specific event having a set priority higher than that of the specific event; when the situation type identification unit identifies the third situation type, the switching mechanism continues to switch the position of the display area to the second position without temporarily switching the position of the display area from the second position to the first position; When the third situation type is identified by the situation type identification unit, the display control unit starts displaying the second content for the new specific event from the timing at which the third situation type is identified, and displays the second content for the new specific event.

9. The virtual image display device according to claim 5 , the situation type identification unit identifies, as the situation type, at least a fourth situation type in which a new specific event has occurred while the switching mechanism is switching the position of the display area to the first position due to an end of the specific event; when the fourth situation type is identified by the situation type identification unit, the switching mechanism changes the position of the display area to the second position even if the position of the display area has not been switched to the first position, When the fourth situation type is identified by the situation type identification unit, the display control unit starts displaying the second content for the new specific event from the timing at which the fourth situation type is identified, and displays the second content for the new specific event.

10. A virtual image display method for displaying a virtual image visible to a driver of a vehicle, comprising: Executed by at least one processor, a switching step of switching a position of a display area where the virtual image is displayed between a plurality of positions including a first position and a second position; a display control process of displaying virtual images of a first content, which is a type of content to be displayed at the first position, and a second content, which is a type of content to be displayed at the second position, in response to switching of the position of the display area by the switching process; an event status specifying step of specifying a status of a specific event which is an event requiring the second content to be displayed; In the switching step, when it is determined in the event status determination step that the specific event has occurred and the position of the display area is not the second position, the display area is switched to the second position, The display control process is a virtual image display method in which, when the event status identification process identifies that the specific event has occurred and the position of the display area is not the second position, the second content is displayed before the switching of the display area to the second position is completed in the switching process.

Images