Virtual image display device and display control device

Abstract

To provide a virtual image display device which can reduce distraction by display of a virtual image, even though the virtual image display device is configured to be capable of switching a display area of the virtual image.SOLUTION: A HUD 100 is a virtual image display device for displaying a virtual image Vi visible by an occupant of a vehicle Am. The HUD 100 includes a displacement mechanism 63 and a display control part. The displacement mechanism 63 switches a position of a 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 display control part displays the virtual image Vi of content associated with the normal position VP1 and the upper position VP2, according to switching of the position of the display area VA by the displacement mechanism 63. The display control part displays the virtual image Vi to which a mode rule associated with at least one of a type of the content and the position of the display area VA is applied, when the position of the display area VA is not the normal position VP1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates to a virtual image display device that displays a virtual image viewable by an occupant of a vehicle. [Background technology]

[0002] Patent Document 1 discloses a virtual image display device equipped with a mechanism for shifting the position of the angle of view at which a virtual image is displayed. In the virtual image display device of Patent Document 1, the range in which a virtual image can be displayed as seen by a vehicle occupant is expanded by shifting the angle of view from a normal position to a superimposed position. [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] In a configuration in which the display area of ​​a virtual image can be switched as in Patent Document 1, the virtual image displayed in the display area moved from the normal position can be a highly eye-catching display object, but there is also a concern that it may be annoying to the occupants. The annoyingness of such a virtual image display can be a cause of distraction.

[0005] An object of the present disclosure is to provide a virtual image display device that can reduce distraction caused by the display of a virtual image even in a configuration in which the display area of ​​the virtual image is switchable. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, one disclosed aspect is a virtual image display device that displays a virtual image (Vi) that is visible to an occupant of a vehicle (Am), and includes a switching mechanism (63) that switches the position of a display area (VA) in which the virtual image is displayed between a plurality of positions including a first position (VP1) and a second position (VP2), and a display control unit (73) that displays virtual images of content (CT) associated with each of the first position and the second position in accordance with the switching of the position of the display area by the switching mechanism, and the display control unit is a virtual image display device that displays a virtual image to which an aspect rule associated with at least one of the type of content and the position of the display area is applied when the position of the display area is not the first position.

[0007] In this aspect, when the switching mechanism moves the display area from the first position, the application of an aspect rule associated with at least one of the type of content and the position of the display area can prevent the virtual image from being displayed in a manner that annoys the occupant. As a result, even in a configuration in which the display area of ​​the virtual image can be switched, the distraction caused by the display of the virtual image can be reduced.

[0008] In addition, the reference numbers in parentheses in the above and claims merely show an example of the correspondence with the specific configurations in the embodiments described below, and do not limit the technical scope in any way. In addition, claims that are not explicitly stated in the claims can be combined together as long as there is no particular problem with the combination. [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]FIG. 13 is a diagram showing an example of a virtual image displayed at a normal position. [Figure 6] 13A to 13C are diagrams for explaining details of size adjustment applied to a bar-shaped image portion displayed at both the normal position and the upper position. [Figure 7] 13A to 13C are diagrams for explaining details of tilt adjustment applied to a line-shaped image portion displayed at both the normal position and the upper position. [Figure 8] FIG. 13 is a diagram showing an example of an automatic braking content displayed in an upper position. [Figure 9] A figure showing details of the changes in the automatic braking content. [Figure 10] FIG. 14 is a diagram showing details of the route guidance content displayed in the upper position, together with FIGS. 11 to 13. [Figure 11] FIG. 14 is a diagram showing details of route guidance content together with FIG. 10, FIG. 12, and FIG. 13. [Figure 12] 11 is a diagram showing details of route guidance content together with FIG. 11 and FIG. 13. FIG. [Figure 13] FIG. 14 is a diagram showing details of route guidance content together with FIG. 11 to FIG. 13. [Figure 14] FIG. 13 is a diagram showing an example of FCTA content displayed in the upper position. [Figure 15] 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] 1 and 2, a head-up display (hereinafter, HUD) 100 according to an embodiment of the present disclosure is a virtual image display device that displays a virtual image Vi. The HUD 100 constitutes a display system 110 together with a meter display device 30 and the like. The display system 110 is used in a vehicle Am, and presents various information related to the vehicle Am to a driver by coordinating a virtual image display by the HUD 100 with a screen display by the meter display device 30 and the like.

[0011] 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.

[0012] The meter display device 30 is one of a plurality of display devices mounted on the vehicle Am, and presents information to the driver by displaying images on a display screen. The meter display device 30 has a configuration equivalent to a combination meter, and is housed in the instrument panel 9 with the display screen facing the driver's seat. The meter display device 30 includes a meter display 31 and a meter ECU 32.

[0013] The meter display 31 is, for example, a liquid crystal display or an organic EL display, etc. Based on video data acquired from the meter ECU 32, the meter display 31 displays a speedometer image, a tachometer image, a navigation map image, a driving assistance image, etc. on a display screen.

[0014] 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.

[0015] The HUD 100 is one of a plurality of display devices mounted on the vehicle Am, and presents information to the driver by a virtual image Vi formed in the space in front of the driver. The HUD 100 is accommodated in a storage space provided inside the instrument panel 9. The HUD 100 projects light formed as the virtual image Vi (hereinafter, display light Lvi) toward a projection range PA of the windshield WS. The display light Lvi projected onto the windshield WS is reflected toward the driver's seat in the projection range PA and 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.

[0016] 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 .

[0017] 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 (a plane mirror described later). The PGU 61 displays each frame image of the video data on the display surface of the LCD panel, transmits and illuminates the display surface with a backlight, and emits display light Lvi, which is focused as a virtual image Vi, toward the magnifying optical system 62.

[0018] 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.

[0019] The displacement mechanism 63 is a mechanism that mechanically moves an area of ​​the windshield WS that becomes the projection range PA. The projection range PA is a range in which the display light Lvi is projected, and is a range in which the virtual image Vi is displayed as seen by the driver. The displacement mechanism 63 is composed of an actuator 63a, a gear unit, and the like. The displacement mechanism 63 rotates the concave mirror 62a around a rotation axis defined along the left-right direction Yo by transmitting the driving force of the actuator 63a to the housing of the concave mirror 62a via the gear unit. 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, and therefore the position of the display area VA viewed by the driver, moves at least in the vertical direction US.

[0020] More specifically, when the virtual range in space where the virtual image Vi can be formed is defined as the imaging surface IS, the display area VA is determined based on a virtual line connecting the driver's eye point EP and the outer edge of the imaging surface IS. 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 (left-right direction Yo) (e.g., about 6°) is set larger than the vertical angle of view in the vertical direction (up-down direction US) (e.g., about 2°).

[0021] The displacement mechanism 63 displaces the position of the display area VA along the up-down direction US of the vehicle Am, and moves the forward range that overlaps with the display area VA in the fore-aft direction ZG. As an example, when the displacement mechanism 63 positions the display area VA downward (e.g., at a depression angle of about 4°), the forward range of 10-20 meters becomes the range within the display area VA. On the other hand, when the displacement mechanism 63 positions the display area VA upward (e.g., at a depression angle of about 2°), the forward range of about 20 meters to 60 meters becomes the range within the display area VA.

[0022] Here, the front-rear direction ZG and the left-right direction Yo are defined based on the vehicle Am stationary on a horizontal plane. Specifically, the front-rear direction ZG is defined along the longitudinal direction (travel direction) of the vehicle Am. The left-right direction Yo is defined along the width direction of the vehicle Am. Furthermore, the up-down direction US is defined along the vertical direction of the horizontal plane that defines the front-rear direction ZG and the left-right direction Yo. For the sake of simplicity, the symbols indicating the respective directions may be omitted as appropriate.

[0023] 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.

[0024] 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 including a processing unit 51, a RAM 52, a storage 53, an input / output interface, and a bus connecting these components. The head-up ECU 70 further includes a drive circuit for driving the LCD panel, the backlight, and the actuator 63a, and a detection circuit for acquiring an output signal from the position sensor 64.

[0025] 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, in cooperation with the displacement mechanism 63, by controlling the driving of the actuator 63a. The head-up ECU 70 displays the virtual images Vi associated with each of the normal position VP1 and the upper position VP2 in response to the switching of the position of the display area VA by the actuator 63a.

[0026] The normal position VP1 is a position of the display area VA that displays a virtual image Vi in the driver's peripheral visual field PVF (see FIG. 3). 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 regular 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 speedometer CTv (see FIG. 3) is displayed. In the following description, the content CT associated with the normal position VP1 is referred to as a 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.

[0027] 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 (see FIG. 3) of the driver. 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 that should be notified to the driver occurs. In the display area VA at the upper position VP2, for example, a route guidance content CTrg (see FIG. 3) and a content CT related to the event, such as a pedestrian notification content, are displayed. In the following description, the content CT associated with the upper position VP2 is referred to as the second content CT2 (see FIG. 3). When an event occurs, the driver can recognize the virtual image Vi of the second content CT2 displayed in the display area VA at the upper position VP2 without significantly deviating his / her line of sight from the front.

[0028] 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.

[0029] In order to realize the virtual image display method described above, the head-up ECU 70 executes a program (virtual image display program) stored in the storage 53 by the processing unit 51, and has a plurality of functional units. Specifically, the head-up ECU 70 has functional units such as an information acquisition unit 71, a data storage unit 72, a display control unit 73, and an abnormality detection unit 74.

[0030] The information acquisition unit 71 is a functional unit that 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, and 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.

[0031] 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, a dedicated switch provided on the instrument panel 9, a steering switch provided on the steering wheel, a center display having a touch panel function, and a voice input device that detects the driver's speech can be used as the operation unit 68. 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.

[0032] 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, and mirror position data and graphic data respectively associated with the normal position VP1 and the upper position VP2 are prepared so as to be referenced by the display control unit 73.

[0033] The lookup table records information linking the position of the display area VA with the content CT. Furthermore, the lookup table records information linking the type of failure that has occurred in the HUD 100 with 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 (material 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 (material data) that is used when the display area VA is in the upper position VP2.

[0034] The display control unit 73 is a control unit that performs integrated control of the PGU 61 and the actuator 63a. The display control unit 73 generates video data and control signals to be output to the PGU 61, and drive signals to be output to the actuator 63a. The display control unit 73 selects content CT to be displayed as a virtual image Vi, and controls the position of the display area VA according to the details of the content CT to be displayed.

[0035] More specifically, the display control unit 73 refers to the lookup table in the data storage unit 72 based on the information acquired by the information acquisition unit 71, and selects the content CT to be displayed as a virtual image and the position of the display area VA. Based on the selection result of the content CT, 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. The display control unit 73 appropriately combines image data generated from the material data with image data provided by the meter ECU 32, and generates 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.

[0036] The display control unit 73 displays virtual images Vi of the content CT associated with each of the normal position VP1 and the upper position VP2 in response to switching of the position of the display area VA by the displacement mechanism 63. When it is determined to move the display area VA, the display control unit 73 switches the content CT to be displayed as a virtual image in association with the start or end of driving of the actuator 63a.

[0037] The abnormality detection unit 74 is connected to the PGU 61, the actuator 63a, and the position sensor 64, and detects various abnormalities occurring in the HUD 100, such as abnormalities in the displacement of the display area VA and abnormalities in the image. Specifically, the abnormality detection unit 74 detects abnormalities in the PGU 61, abnormalities in the actuator 63a, malfunctions of the gear unit, as well as circuit abnormalities in the head-up ECU 70 and software abnormalities in the virtual image display program. When the display control unit 73 detects an abnormality in the HUD 100, it provides the display control unit 73 with information indicating the abnormality detection (hereinafter, abnormality detection information) and information indicating the type of the detected abnormality (hereinafter, abnormality type information).

[0038] The display control process performed mainly by the display control unit 73 in the head-up ECU 70 will be described in detail below with reference to Fig. 4, Fig. 1 and Fig. 2. After the start of power supply to the HUD 100, the display control unit 73 starts the display control process shown in Fig. 4 when the power supply to the head-up ECU 70 is turned on. In the display control process, occurrence of a fault related to 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.

[0039] In S101 of the display control process, 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. When the display control unit 73 determines that abnormality detection information has been acquired and that a fault has occurred (S101: YES), in S102, the display control unit 73 determines the type of fault based on the abnormality type information acquired from the abnormality detection unit 74.

[0040] In S103, the display control unit 73 selects an avoidance method that is pre-associated with the identified type of obstacle by referring to the lookup table in the data storage unit 72. Then, the display control unit 73 performs a display process (fail-safe display process) that changes the content of the virtual image display according to the selected avoidance method so as not to hinder normal driving by the driver.

[0041] On the other hand, when the display control unit 73 has not acquired abnormality detection information from the abnormality detection unit 74 and has determined that no failure has occurred (S101: NO), the display control unit 73 determines the position of the display area VA in S104. Specifically, based on the information acquired by the information acquisition unit 71, the display control unit 73 selects the content CT to be displayed as a virtual image and the position of the display area VA by referring to the lookup table in the data storage unit 72.

[0042] When the display control unit 73 determines that the display area VA is to be set to the normal position VP1 (S104: NO), in S105 and S106, the display control unit 73 reads the mirror position data and the graphic data associated with the normal position VP1 from the data storage unit 72. Then, in S107, the display control unit 73 displays the virtual image Vi of the content CT, the display of which was determined in S104, in the display area VA of the normal position VP1.

[0043] On the other hand, when the display control unit 73 determines that the display area VA is to be set to the upper position VP2 (S104: YES), in S108 and S109, it reads the mirror position data and the graphic data associated with the upper position VP2 from the data storage unit 72. Then, in S110, the display control unit 73 displays the virtual image Vi of the content CT, the display of which was determined in S104, in the display area VA at the upper position VP2.

[0044] In the above display control process, if the position of the selected display area VA is not the normal position VP1 (S104: YES), the display control unit 73 displays the virtual image Vi to which a mode rule associated with at least one of the type of content CT and the position of the display area VA is applied. When the position of the display area VA is not the normal position VP1, this includes the case where the display area VA is at the upper position VP2 or the case where the display area VA is moving.

[0045] The display control unit 73 can display the content CT in an expression method that is less bothersome and less eye-catching by applying the aspect rules to the virtual image Vi. In this embodiment, a lookup table and graphic data corresponding to a plurality of preset 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 rules have been appropriately applied by referring to the lookup table and the graphic data. The details of the plurality of types of aspect rules used in this embodiment will be described below in order.

[0046] <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 restricted 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.

[0047] [Limits on text information] The display control unit 73 applies the first aspect rule to the text information MJ (see FIG. 8) 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 (volume) of the text information MJ at the upper position VP2 is reduced compared to the normal position VP1.

[0048] 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.

[0049] [Background fill limit] The display control unit 73 applies the first aspect rule to the filled-in background NH (see FIG. 8) 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 displayed in a chromatic, high-brightness display color (e.g., red). On the other hand, the text information MJ is displayed in an achromatic, high-brightness display color (e.g., white).

[0050] 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.

[0051] 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. 9). Specifically, the display control unit 73 limits the duration of display of the filled-in background NH to a very short time (for example, about 0.1 seconds). After the display control unit 73 prompts the driver's attention by displaying the filled-in background NH for a short period of time, it 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. 9) 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.

[0052] <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.

[0053] [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 to make the virtual image Vi displayed at the normal position VP1 invisible before the movement of the display area VA starts. As an example, when the speedometer CTv and the route guidance content CTrg are displayed at the normal position VP1 as the first content CT1, the display control unit 73 makes these virtual images Vi invisible and then starts the movement of the display area VA by the displacement mechanism 63 (see FIG. 5). After the display area VA moves to the upper position VP2, the display control unit 73 redisplays the speedometer CTv and the route guidance content CTrg.

[0054] Similarly, when the displacement mechanism 63 moves the display area VA from the upper position VP2 to the normal position VP1, the display control unit 73 may hide the virtual image Vi that was displayed at the upper position VP2 before the movement of the display area VA starts. 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.

[0055] [Size adjustment in perspective direction] When displaying the content CT common to before and after the movement from the normal position VP1 to the upper position VP2, 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 by applying the second aspect rule. As an example, when the first content CT1 including the bar-shaped image portion Phb extending along the horizontal direction (left-right direction Yo) is displayed at the normal position VP1, the display control unit 73 reduces the bar-shaped image portion Phb in the perspective direction and displays it at the upper position VP2 (see FIG. 6). The bar-shaped image portion Phb is included in the content CT indicating the operation of ACC (Adaptive Cruise Control), for example, and is displayed as an image portion indicating a vehicle ahead.

[0056] If a bar-shaped image portion Phb with the same display size as that of the normal position VP1 is displayed at the upper position VP2 (see the two-dot chain line in FIG. 6), the bar-shaped image portion Phb will be enlarged relative to the foreground, which 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 (see the dashed line in FIG. 6) that converge on the vanishing point VNP. By adjusting the display size in this way, unintended emphasis due to the Pongee illusion is avoided.

[0057] [Tilt adjustment taking vanishing point into account] When displaying the content CT including the line-shaped image portion PbL extending toward the vanishing point VNP in the foreground 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 to the line-shaped image portion PbL. The display control unit 73 adjusts the inclination of the line-shaped image portion PbL so that the attitude toward the vanishing point VNP is maintained (see FIG. 7). 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. 15).

[0058] 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 (see dashed lines in FIG. 7) 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.

[0059] 6 and 7 are virtual lines used for explanation and are not actually displayed. Moreover, 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.

[0060] <Third aspect rule> The third aspect rule is a aspect rule associated with both the type of content CT and the position of the display area VA. The third aspect rule is applied to AR (Augmented Reality, see FIG. 3) content CTs displayed in the display area VA at the upper position VP2. The display position of the AR content CTs is associated with a specific superimposed object in the foreground, and the AR content CTs can move as seen by the driver by following the superimposed object as if it were fixed relatively to the superimposed object. The display control unit 73 recognizes, for example, a specific position on the road surface, a vehicle ahead, a pedestrian, a road sign, and the like as the superimposed object. The display control unit 73 continuously maintains the relative positional relationship between the driver's eye point EP, the superimposed object in the foreground, and the AR content CTs.

[0061] [Overlap limit with overlapping objects] When displaying the AR content CTs at the upper position VP2, the display control unit 73 avoids displaying the AR content CTs superimposed on the superimposition target itself that draws the driver's attention by applying the third aspect rule. The display control unit 73 superimposes and displays the AR content CTs at a position slightly away from the superimposition target.

[0062] As an example, the second content CT2 (see FIG. 7) including the line-shaped image portion PbL is displayed as the AR content CTs with the lane marking of the vehicle's lane as the superimposition target. Specifically, the content CT indicating the operation of LDW (Lane Departure Warning) and LTC (Lane Trace Control) by the driving assistance ECU 22 is displayed as the AR content CTs including the line-shaped image portion PbL. 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. As a result, the area where the AR content CTs and the superimposition target overlap (hereinafter, the overlapping area) as seen by the driver is set to zero. The display control unit 73 may allow a slight overlap between the AR content CTs and the superimposition target. In this case, the overlapping area is set to a predetermined value or less. The above overlap restriction prevents the driver from being excessively drawn to the superimposed object, and further prevents the driver from being motivated to unintentionally match the AR content CTs with the superimposed object.

[0063] <Fourth aspect rule> The fourth aspect rule is a aspect rule that is linked to both the type of content and the position of the display area VA. The fourth aspect rule is applied to a specific type of content CT displayed in the display area VA at the upper position VP2 in order to reduce the cognitive load of the content CT and shorten the time required for the driver to recognize, judge, and operate the content CT. 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.

[0064] [Automatic Brake Content] 8 and 9 at the upper position VP2, the display control unit 73 applies the fourth aspect rule to the automatic braking content CTpc. The automatic braking content CTpc is content CT that notifies the driver of the operation of the collision damage mitigation brake (Autonomous Emergency Braking) by the driving assistance ECU 22 (see FIG. 2). 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.

[0065] The display control unit 73 applies the fourth aspect rule, which includes the above-mentioned first aspect rule, to the automatic braking content CTpc. Specifically, 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 so that the driver quickly notices the warning (see the upper part of FIG. 9).

[0066] In addition, the display control unit 73 adds a dark outline Ri to each character of the character information MJ and limits the number and size of characters in the character information MJ to improve readability of the character information MJ (see the middle part of Fig. 8 and Fig. 9). Furthermore, after encouraging the driver to notice, 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 so as not to obstruct the driver's forward view (see the lower part of Fig. 9).

[0067] [Route Guidance Content] When displaying the route guidance content CTrg shown in Figs. 10 to 13 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 (see Fig. 2), 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.

[0068] 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, etc. The arrow image section PgA includes a number of arrow-shaped image elements aligned in the left-right direction Yo. The arrow image section PgA indicates the travel direction of the vehicle (to the right in FIG. 10) at a guidance point (e.g., an intersection, etc.) with each image element. 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 is superimposed on the road surface ahead to provide guidance on the planned route of the vehicle at the guidance point (a right turn in FIG. 10). The remaining distance meter Pdm indicates the remaining distance to the guidance point as a numerical value based on route information.

[0069] The display control unit 73 moves the display area VA from the normal position VP1 (see FIG. 5) to the upper position VP2 just before the remaining distance to the guidance point becomes about 100 m. If the route guidance content CTrg (see FIG. 5) is displayed at the normal position VP1, the display control unit 73 hides the route guidance content CTrg before the movement of the display area VA starts, in accordance with the first aspect rule. The display control unit 73 may fade out the route guidance content CTrg toward the guidance point (vanishing point VNP, see FIG. 6).

[0070] 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. 10). By applying the fourth behavior rule to the route guidance content CTrg, the display control unit 73 limits changes in the behavior of the route guidance content CTrg until the remaining distance from the vehicle Am (see FIG. 1) to the guidance point becomes less than a predetermined value. As an example, the display control unit 73 fixes the behavior of the route guidance content CTrg until the remaining distance becomes less than 50 m. Then, when the remaining distance becomes less than 50 m, the display control unit 73 changes the behavior of the route guidance content CTrg according to the remaining distance from the vehicle Am to the guidance point.

[0071] 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. 10). 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 FIGS. 11 and 12). 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 route guidance (see FIG. 13).

[0072] 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 starts an animation display in which the display color of each image element of the arrow image unit PgA is changed in sequence in the direction in which the vehicle Am turns right or left (see Figs. 11 and 12). The display control unit 73 continues the animation display of the arrow image unit PgA until the vehicle Am finishes turning right or left (see Fig. 13).

[0073] 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 display color of the route guidance content CTrg, or displays an animation, to help the driver understand the remaining distance. Specifically, the display control unit 73 changes the display color of the road marking unit Prm from an achromatic color (e.g., gray, etc.) to a chromatic color (e.g., blue or light blue, etc.) that is the same as or similar to that of the arrow image unit PgA when the remaining distance becomes less than 50 m (see FIG. 11). Furthermore, the display control unit 73 continuously changes the shape of the road marking unit Prm as the vehicle Am approaches the guidance point (see FIGS. 11 to 13).

[0074] The above route guidance content CTrg can visually show the 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 is moved, the annoyance caused by switching the display area VA is reduced.

[0075] [FCTA Content] When displaying the FCTA (Front Cross Traffic Alert) content CTta shown in Fig. 14 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 (hereinafter, approaching vehicles Av) approaching from the front left and right of the vehicle Am (see Fig. 1) among risk objects around the vehicle Am. The FCTA content CTta is displayed based on the recognition of the approaching vehicle Av by the driving assistance ECU 22 (see Fig. 2) in a scene such as entering an intersection.

[0076] 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. 14). 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.

[0077] When the display control unit 73 displays the FCTA content CTta at the upper position VP2, 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 (see FIG. 3) to the upper position VP2 by applying the fourth aspect rule. When the approaching vehicle Av is approaching from the left side of the host 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. 14). On the other hand, when the approaching vehicle Av is approaching from the right side of the host 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.

[0078] 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 differentiated by display color and shape from the route guidance content CTrg (see FIG. 5, FIG. 10, etc.). Specifically, the display control unit 73 displays the FCTA content CTta composed of an approaching vehicle warning icon PaC and a plane arrow image portion PaR, etc., in a display color (e.g., yellow or amber) different from the route guidance content CTrg (e.g., blue or light blue, etc.).

[0079] 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.

[0080] The surface arrow image section PaR has a shape extending in a band shape along the left-right direction Yo. A gradation expression in the left-right direction Yo is adopted for the surface arrow image section PaR. 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 (the left side in FIG. 14), and an animation display that flows from the side closer to the approaching vehicle Av as a starting point emphasizes the relative position of the approaching vehicle Av to the driver.

[0081] As described above, the planar arrow image section PaR is clearly differentiated from the arrow image section PgA of the route guidance content CTrg (see Figs. 5 and 10, etc.) by adopting an expression that combines a planar arrow shape with a gradation expression. In addition, the approaching vehicle warning icon PaC superimposed on the planar arrow image section PaR instantly informs the driver that it is a warning. As a result, the FCTA content CTta is less likely to be mistaken for the route guidance content CTrg.

[0082] [Avoidance support content] When displaying the avoidance support content CTas shown in Fig. 15 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 among risk objects around the vehicle Am (see Fig. 1). The avoidance support content CTas is displayed when the driving support ECU 22 (see Fig. 2) recognizes a pedestrian PE, etc., and the driving support ECU 22 implements steering support control or deceleration support control to avoid the pedestrian PE, etc.

[0083] 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. 15). 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.

[0084] When displaying the avoidance assistance content CTas at the upper position VP2, the display control unit 73 sets a non-display area ANP within the display area VA that has moved to the upper position VP2 by applying the fourth aspect rule. When a pedestrian PE or the like is approaching from the left side of the host 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. 15). On the other hand, when a pedestrian PE or the like is approaching from the right side of the host 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.

[0085] 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 (see FIG. 3) to the upper position VP2. As an example, the display control unit 73 displays the avoidance support content CTas composed of the pedestrian warning icon PaP and the line-shaped image portion PbL, etc., in a single color (e.g., yellow or amber).

[0086] The pedestrian warning icon PaP is an image part in which an icon resembling a pedestrian PE is surrounded by a triangular frame, and alerts the driver to the presence of a pedestrian PE. The pedestrian warning icon PaP indicates the direction of movement of the pedestrian PE with a minimum of elements by drawing the dynamic poses of the hands and feet on the icon and a diagonal posture that becomes deeper as it approaches the center.

[0087] The line-shaped image portion PbL is an image portion that extends toward the vanishing point VNP (see FIG. 7) in the foreground. The line-shaped image portion PbL is disposed so as to be in contact with the end portion of the lower center 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.

[0088] As described above, the display control unit 73 makes it easy for the driver to recognize the pedestrian PE by displaying the avoidance assistance content CTas in a large, easily visible manner. Furthermore, by setting the non-display area ANP and the pedestrian warning icon PaP displayed in a single color at an angle, the avoidance assistance content CTas can instantly inform the driver of the left and right directions in which the pedestrian PE is approaching.

[0089] <Summary of the embodiment> In the present embodiment described so far, when the displacement mechanism 63 moves the display area VA from the normal position VP1, a mode rule associated with at least one of the type of the content CT and the position of the display area VA is applied to the virtual image Vi. This can prevent the virtual image Vi from being displayed in a manner that causes annoyance to passengers such as the driver. As a result, even if the display area VA of the virtual image Vi is configured to be switchable, the distraction caused by the display of the virtual image Vi can be reduced.

[0090] In addition, in this embodiment, in order to notify information to occupants such as the driver in various situations without feeling uncomfortable, a representation method that is unlikely to affect the annoyance or attention caused by fluctuations in the display area VA is adopted based on the first to fourth aspect rules.

[0091] Specifically, in this embodiment, by applying the first aspect rule to the character information MJ displayed at the upper position VP2 above the normal position VP1, at least one of the number of characters and the character size of the character information MJ is limited compared to when the character information MJ is displayed at the normal position VP1. As a result, it is 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.

[0092] In this embodiment, the first rule is applied to the filled-in background NH displayed at the upper position VP2, and the display duration of the filled-in background NH is limited. As a result, it becomes difficult for a wide area to be filled in and obstruct the driver's view for a long period of time.

[0093] Furthermore, in this embodiment, when the character information MJ is displayed at the upper position VP2 superimposed on the filled-in background NH, the outline Ri of the character included in the character information MJ is emphasized in a color different from that of the filled-in background NH. By adding such outline Ri, the readability of the character information MJ is improved. As a result, even if the character information MJ is displayed near the central visual field CVF, excessive attention is unlikely to be generated.

[0094] In addition, in this embodiment, by applying the fourth aspect rule, the aspect of the route guidance content CTrg used for route guidance at the guide point changes according to the remaining distance from the vehicle Am to the guide point. 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.

[0095] In this embodiment, the fourth aspect rule is applied to the FCTA content CTta and the avoidance support content CTas that notify risk objects (approaching vehicles Av and pedestrians PE, etc.) around the vehicle Am. As a result, a non-display area ANP in which the virtual image Vi is not displayed is set within the display area VA that has moved from the normal position VP1 to the upper position VP2. By setting the non-display area ANP in this way, the visibility of the FCTA content CTta and the avoidance support content CTas that notify risk objects 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.

[0096] Furthermore, in this embodiment, the application of the fourth aspect rule to the FCTA content CTta and the avoidance support content CTas limits 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. Specifically, the FCTA content CTta and the avoidance support content CTas are displayed in a single color such as amber to call attention. Such a restriction on the display colors can assist the driver in instantaneous understanding of information.

[0097] In addition, in this embodiment, the FCTA content CTta that notifies the approaching vehicle Av is differentiated from the route guidance content CTrg used for route guidance at the guidance point by the application of the fourth aspect rule, so that the FCTA content CTta that indicates the direction of the approaching vehicle Av is less likely to be mistaken for the route guidance content CTrg that indicates the traveling direction of the vehicle.

[0098] In this embodiment, when the displacement mechanism 63 moves the display area VA from the normal position VP1 to the upper position VP2, the virtual image Vi displayed at the normal position VP1 is made invisible before the display area VA starts to move due to application of the second aspect rule. Therefore, the virtual image Vi displayed when the display area VA moves is unlikely to attract the driver's attention and cause discomfort.

[0099] Furthermore, in this embodiment, when a common content CT is displayed before and after the movement from the normal position VP1 to the upper position VP2, the display size of the virtual image Vi is adjusted so that the relationship with the vanishing point VNP in the foreground is maintained by applying the second aspect rule. Therefore, it is possible to avoid a situation in which unintended emphasis is caused by the content CT (e.g., the bar-shaped image portion Phb, etc.) that has moved to the upper position VP2.

[0100] In addition, in this embodiment, when the content CT including the line-shaped image portion PbLPbL extending toward the vanishing point VNP in the foreground is displayed before and after moving from the normal position VP1 to the upper position VP2, the second aspect rule is applied. As a result, the inclination of the line-shaped image portion PbL is adjusted so that the orientation toward the vanishing point VNP is maintained. Therefore, it becomes difficult for a situation to occur in which the deviation of the orientation of the line-shaped image portion PbL with respect to the dividing line or the like in the foreground causes a sense of incongruity.

[0101] In the above embodiment, the normal position VP1 corresponds to the "first position", the upper position VP2 corresponds to the "second position", the displacement mechanism 63 corresponds to the "switching mechanism", and the HUD 100 corresponds to the "virtual image display device". Furthermore, the FCTA content CTta and the avoidance support content CTas correspond to the "notification content".

[0102] (Other embodiments) Although one embodiment of the present disclosure has been described above, the present disclosure should not be construed as being limited to the above embodiment, and can be applied to various embodiments and combinations within the scope not departing from the gist of the present disclosure.

[0103] In the first modification of the above embodiment, 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, the contents of which change in real time, is not displayed in the display area VA in the upper position VP2. Furthermore, in the first modification, the solid background NH is not displayed in the display area VA in the upper position VP2.

[0104] The displacement mechanism 63 of the second modification of the above embodiment can displace the display area VA in the left-right direction Yo in addition to the up-down direction US. Furthermore, the displacement mechanism 63 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.

[0105] In the third modification of the above embodiment, real-time detection information of the eye point EP by the driver monitor is provided to the head-up ECU 70. The display control unit 73 adjusts each position of the display area VA and the display position of the virtual image Vi in accordance with the current position of the eye point EP based on the detection information in cooperation with the driver monitor.

[0106] In the above embodiment, the content CT to which each aspect rule is applied is not limited to the above-mentioned automatic brake content CTpc, route guidance content CTrg, FCTA content CTta, and avoidance support content CTas. For example, each aspect rule can be applied to various contents CT that can be displayed by the HUD 100, such as ACC content, LTC content, RSA (Road Sign Assist) content, and narrow road driving support content.

[0107] 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.

[0108] In a fourth modification of the above embodiment, 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 this fourth modification, a system including the meter ECU 32 or another in-vehicle ECU becomes a "virtual image display device."

[0109] Furthermore, in the fifth modification of the above embodiment, some 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, a system including the HUD 100 and the HCU becomes a "virtual image display device."

[0110] The PGU 61 of the above embodiment 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.

[0111] The processing units provided in the head-up ECU 70 and the meter ECU 32 in the above embodiment are hardware for arithmetic processing coupled with a RAM. The processing units include at least one arithmetic core such as a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The processing units may further include, for example, an FPGA (Field-Programmable Gate Array) 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.

[0112] The storage includes a non-volatile storage medium (non-transitory tangible storage medium). Various programs (display control program, etc.) executed by the processing unit are stored in the storage of each ECU 32, 70. Such a storage medium is not limited to a configuration 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, etc., from which the programs are copied or distributed to each ECU 32, 70.

[0113] In the above embodiment, 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 also be provided by digital circuits including a large number of logic circuits, or analog circuits.

[0114] The vehicle equipped with the above-mentioned display system is not limited to a general private passenger car, and 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 may be a right-hand drive vehicle or a left-hand drive vehicle. Furthermore, the traffic environment in which the vehicle runs may be a traffic environment based on left-hand traffic or a traffic environment based 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.

[0115] 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.

[0116] (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.

[0117] (Technical thought 1) A virtual image display device that displays a virtual image (Vi) visible to an occupant of a vehicle (Am), a switching mechanism (63) that switches the position of a display area (VA) in which the virtual image is displayed between a plurality of positions including a first position (VP1) and a second position (VP2); a display control unit (73) that displays the virtual images of the content (CT) associated with each of the first position and the second position in response to switching of the position of the display area by the switching mechanism, The display control unit is a virtual image display device that displays the virtual image by applying a mode rule associated with at least one of the type of content and the position of the display area when the position of the display area is not the first position. (Technical thought 2) The display control unit of the virtual image display device according to technical idea 1 limits at least one of the number of characters and the character size of character information (MJ) to be displayed at the second position above the first position by applying the aspect rule. (Technical Thought 3) The virtual image display device according to Technical Idea 1 or 2, wherein the display control unit limits the time for which the filled-in background (NH) displayed at the second position above the first position is displayed by applying the aspect rule. (Technical Thought 4) The virtual image display device described in Technical Idea 3, wherein when the display control unit displays text information (MJ) at the second position by superimposing it on the filled-in background, emphasizes the outlines of characters contained in the text information in a color different from that of the filled-in background. (Technical Thought 5) The virtual image display device according to any one of Technical Ideas 1 to 4, wherein the display control unit changes the appearance of route guidance content (CTrg) used for route guidance at a guidance point according to the remaining distance from the vehicle to the guidance point by applying the appearance rule. (Technical Thought 6) The virtual image display device described in any one of Technical Ideas 1 to 5, wherein when the display control unit displays notification content (CTta, CTas) that notifies of risk objects around the vehicle at the second position, by applying the aspect rule, sets a non-display area (ANP) in which the virtual image is not displayed within the display area that has moved from the first position to the second position. (Technical Thought 7) The virtual image display device described in Technical Idea 1, in which the display control unit, when displaying notification content (CTta, CTas) that notifies of risk objects around the vehicle at the second position, limits the number of display colors that can be used for the virtual image after the display area moves from the first position to the second position by applying the aspect rule. (Technical Thought 8) The display control unit is a virtual image display device described in any one of technical ideas 1 to 7, which displays, by applying the aspect rule, an alert content (CTta) that alerts risk objects around the vehicle in a manner differentiated by display color and shape from a route guidance content (CTrg) used for route guidance at a guidance point. (Technical Thought 9) The virtual image display device described in any one of Technical Ideas 1 to 8, wherein when the switching mechanism moves the display area from the first position to the second position, the display control unit applies the aspect rule to make the virtual image that was displayed at the first position invisible before the movement of the display area begins. (Technical Thought 10) The virtual image display device described in any one of Technical Ideas 1 to 9, wherein when the display control unit displays the content that is common before and after the movement from the first position to the second position, the display control unit adjusts the display size of the virtual image by applying the aspect rule so that the relationship with a vanishing point (VNP) in the foreground is maintained. (Technical Thought 11) A virtual image display device described in any one of Technical Ideas 1 to 10, wherein when the display control unit displays the content including a line-shaped image portion (PbL) extending toward a vanishing point (VNP) in the foreground before and after movement from the first position to the second position, the display control unit adjusts the inclination of the line-shaped image portion by applying the aspect rule so that the attitude toward the vanishing point is maintained. [Explanation of symbols]

[0118] Am vehicle, ANP hidden area, CT content, CTas avoidance support content (notification content), CTrg route guidance content, CTta FCTA content (notification content), MJ character information, NH filled background, PaR plane arrow image section, PbL line-shaped image section, Ri contour, VA display area, Vi virtual image, VNP vanishing point, VP1 normal position (first position), VP2 upper position (second position), 63 displacement mechanism (switching mechanism), 73 display control section, 100 HUD (virtual image display device)

Claims

1. A virtual image display device that displays a virtual image (Vi) that is visible to an occupant of a vehicle (Am), A switching mechanism (63) that switches the position of a display area (VA) in which the virtual image is displayed between a plurality of positions including a first position (VP1) and a second position (VP2); a display control unit (73) that displays the virtual images of the content (CT) associated with each of the first position and the second position in response to switching of the position of the display area by the switching mechanism, The display control unit is When the position of the display area is not the first position, the virtual image is displayed by applying a mode rule associated with at least one of the type of the content and the position of the display area; A virtual image display device that limits the duration of display of a filled-in background (NH) displayed at the second position above the first position by applying the aspect rule.

2. 2. The virtual image display device according to claim 1, wherein when the display control unit displays character information (MJ) at the second position by superimposing the character information on the filled-in background, the display control unit emphasizes the outlines of characters contained in the character information in a color different from that of the filled-in background.

3. The virtual image display device of claim 1, wherein when the display control unit displays notification content (CTta, CTas) that notifies of risk objects around the vehicle at the second position, the display control unit sets a non-display area (ANP) in which the virtual image is not displayed within the display area that has moved from the first position to the second position by applying the aspect rule.

4. A virtual image display device that displays a virtual image (Vi) that is visible to an occupant of a vehicle (Am), A switching mechanism (63) that switches the position of a display area (VA) in which the virtual image is displayed between a plurality of positions including a first position (VP1) and a second position (VP2); a display control unit (73) that displays the virtual images of the content (CT) associated with each of the first position and the second position in response to switching of the position of the display area by the switching mechanism, The display control unit is When the position of the display area is not the first position, the virtual image is displayed by applying a mode rule associated with at least one of the type of the content and the position of the display area; When displaying notification content (CTta, CTas) that notifies of risk objects around the vehicle at the second position, a virtual image display device sets a non-display area (ANP) in which the virtual image is not displayed within the display area that has moved from the first position to the second position by applying the aspect rule.

5. 2. The virtual image display device according to claim 1, wherein the display control unit limits at least one of the number of characters and the character size of character information (MJ) to be displayed at the second position above the first position by applying the aspect rule.

6. The virtual image display device according to claim 1 or 4, wherein the display control unit changes the appearance of route guidance content (CTrg) used for route guidance at a guidance point depending on a remaining distance from the vehicle to the guidance point by applying the appearance rule.

7. The virtual image display device of claim 1 or 4, wherein when the display control unit displays notification content (CTta, CTas) that notifies of risk objects around the vehicle at the second position, by applying the aspect rule, the number of display colors that can be used for the virtual image is limited after the display area moves from the first position to the second position.

8. The virtual image display device of claim 1 or 4, wherein the display control unit displays notification content (CTta) that notifies of risk objects around the vehicle in a manner differentiated by display color and shape from route guidance content (CTrg) used for route guidance at a guidance point by applying the aspect rule.

9. 5. The virtual image display device according to claim 1, wherein when the switching mechanism moves the display area from the first position to the second position, the display control unit applies the aspect rule to make the virtual image displayed at the first position invisible before the movement of the display area begins.

10. 5. The virtual image display device according to claim 1 or 4, wherein when the display control unit displays the content that is common before and after the movement from the first position to the second position, the display control unit adjusts the display size of the virtual image by applying the aspect rule so as to maintain a relationship with a vanishing point (VNP) in the foreground.

11. The virtual image display device of claim 1 or 4, wherein when the display control unit displays the content including a line-shaped image portion (PbL) extending toward a vanishing point (VNP) in the foreground before and after movement from the first position to the second position, the display control unit adjusts the inclination of the line-shaped image portion by applying the aspect rule so that the orientation toward the vanishing point is maintained.

12. A display control device that displays a virtual image (Vi) visible to an occupant of a vehicle (Am), cooperates with a virtual image display device that switches the position of a display area (VA) in which the virtual image is displayed by a switching mechanism (63), and controls the display of the virtual image, a display control unit (73) that displays the virtual images of the content (CT) associated with each of the first position (VP1) and the second position (VP2) in response to switching of the position of the display area by the switching mechanism between a plurality of positions including the first position (VP1) and the second position (VP2), The display control unit is When the position of the display area is not the first position, the virtual image is displayed by applying a mode rule associated with at least one of the type of the content and the position of the display area; A display control device that limits the time for which a solid background (NH) displayed at the second position above the first position is displayed by applying the aspect rule.

13. A display control device that displays a virtual image (Vi) visible to an occupant of a vehicle (Am), cooperates with a virtual image display device that switches the position of a display area (VA) in which the virtual image is displayed by a switching mechanism (63), and controls the display of the virtual image, a display control unit (73) that displays the virtual images of the content (CT) associated with each of the first position (VP1) and the second position (VP2) in response to switching of the position of the display area by the switching mechanism between a plurality of positions including the first position (VP1) and the second position (VP2); The display control unit is When the position of the display area is not the first position, the virtual image is displayed by applying a mode rule associated with at least one of the type of the content and the position of the display area; When displaying notification content (CTta, CTas) that notifies of risk objects around the vehicle at the second position, a display control device sets a non-display area (ANP) in which the virtual image is not displayed within the display area that has moved from the first position to the second position by applying the aspect rule.

Images