Head-up display device

Abstract

To provide a head-up display device configured to switch between a real image and a virtual image before a trigger condition for switching occurs.SOLUTION: A head-up display device 1 configured to execute switching between a virtual-image display state in which a virtual image VI of a display image is visually recognized and a real-image display state in which a real image RI of the display image is visually recognized, upon occurrence of a predetermined trigger condition includes: a display unit 12 which transmits the light emitted from a light source 11 and displays a display image; a reflection unit 13 which reflects the light representing the display image displayed by the display unit 12 toward a window shield WS; and a control unit 15. The control unit 15 executes: a sign detection process to detect a sign of occurrence of a trigger condition; and a switching process to switch, when the sign is detected in the sign detection process, between the virtual-image display state and the real-image display state before the occurrence of the trigger condition.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a head-up display device that displays information to a viewer at a desired timing. [Background technology]

[0002] A known head-up display device is disclosed in Patent Document 1, for example. In this head-up display device, an image displayed on a screen by light from a display device is reflected onto a light-transmitting member, and the front-to-back positional relationship between the optical focus of an imaging optical system and the screen is changed to switch the display between a state in which a virtual image is viewed outside the light-transmitting member and a state in which a real image is viewed inside the light-transmitting member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-70074 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional head-up display device described above has a problem in that when switching between a real image and a virtual image, the timing of the switching does not match the viewer's line of sight, which can be annoying. That is, when switching between a real image and a virtual image, there is usually a trigger condition, but the viewer tends to shift only their line of sight as a preparatory action prior to the image switching. In other words, there is a problem in that the timing of the viewer's line of sight as a preparatory action does not match the timing of the image switching, which causes a sense of discomfort for the viewer.

[0005] Therefore, the present invention has been made in consideration of the above-mentioned problems, and aims to provide a head-up display device that switches between a real image and a virtual image in advance, before the trigger condition for switching occurs. [Means for solving the problem]

[0006] The present invention provides a head-up display device 1 that is provided in a vehicle C having a seat for a passenger DR and a light-transmitting member WS, and that, when a display image represented by the display light L is visually recognized by emitting display light L from an emission port 17 toward the light-transmitting member WS, can switch between a virtual image VI display state in which a virtual image VI of the display image is visually recognized and a real image RI display state in which a real image RI of the display image is visually recognized upon occurrence of a predetermined trigger condition, and the head-up display device 1 includes display units (12a, 12b) that include a display element, transmit light emitted from light sources 11 (11a, 11b), and display the display image. 2b), a reflecting unit 13 that reflects light representing the display image displayed on the display units (12a, 12b) toward the light-transmitting member WS, and a control unit 15, wherein the control unit 15 executes a sign detection process S1 that detects a sign of the occurrence of the trigger condition, and when the sign is detected in the sign detection process S1, switching processes S3, S4 that switch from the virtual image VI display state to the real image RI display state or switch from the real image RI display state to the virtual image VI display state prior to the occurrence of the trigger condition. [Effects of the Invention]

[0007] According to the present invention, instead of switching between a real image and a virtual image when a trigger condition occurs, by switching between a real image and a virtual image in advance of the occurrence of the trigger condition, it is possible to perform optimal control suited to preparatory actions such as shifting the passenger's line of sight, and it is also possible to prompt the passenger to perform the preparatory action itself. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing the configuration of a head-up display device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a functional block diagram showing the configuration of a control unit in the head-up display device according to the first embodiment of the present invention. [Figure 3] A figure showing (A) the switching state between automatic driving mode and manual driving mode over time, (B) the switching state of the ON / OFF state of the second PGU that displays a virtual image over time, and (C) the switching state of the ON / OFF state of the first PGU that displays a real image over time when a switching processing unit in a head-up display device according to the first embodiment of the present invention simultaneously switches between a real image and a virtual image. [Figure 4] A figure showing (A) the switching state between automatic driving mode and manual driving mode over time, (B) the switching state of the ON / OFF state of the second PGU that displays a virtual image over time, and (C) the switching state of the ON / OFF state of the first PGU that displays a real image over time, when a switching processing unit in a head-up display device according to the first embodiment of the present invention switches between a real image and a virtual image over a predetermined period of time. [Figure 5] A figure showing (A) the switching state between automatic driving mode and manual driving mode over time, (B) the switching state of the ON / OFF state of the second PGU that displays a virtual image over time, and (C) the switching state of the ON / OFF state of the first PGU that displays a real image over time when a switching processing unit in a head-up display device according to the first embodiment of the present invention switches between a real image and a virtual image at different times. [Figure 6] 1A and 1B are diagrams showing a positional relationship in which a virtual image and a real image do not overlap as seen by the driver in a head-up display device according to a first embodiment of the present invention; [Figure 7] 5 is a flowchart showing the operation of a control unit when a trigger condition is detected in the head-up display device according to the first embodiment of the present invention. [Figure 8]A second figure showing (A) the switching state between automatic driving mode and manual driving mode over time, (B) the switching state of the ON / OFF state of the second PGU that displays a virtual image over time, and (C) the switching state of the ON / OFF state of the first PGU that displays a real image over time when a switching processing unit in a head-up display device according to the first embodiment of the present invention switches between a real image and a virtual image over a predetermined period of time. [Figure 9] A second figure showing (A) the switching state between automatic driving mode and manual driving mode over time, (B) the switching state of the ON / OFF state of the second PGU that displays a virtual image over time, and (C) the switching state of the ON / OFF state of the first PGU that displays a real image over time when the switching processing unit in the head-up display device of the first embodiment of the present invention switches between real images and virtual images at different times. [Figure 10] FIG. 10 is a diagram showing a configuration for generating a virtual image in a head-up display device according to a second embodiment of the present invention. [Figure 11] FIG. 10 is a diagram showing a configuration for generating a real image in a head-up display device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment of the present invention) A head-up display device (hereinafter referred to as an HUD device) according to this embodiment will be described with reference to Figures 1 to 9. Figure 1 is a diagram showing the configuration of the HUD device according to this embodiment.

[0010] In FIG. 1, the HUD device 1 includes a first PGU 10a having a first light source 11a that emits light in the visible wavelength range, for example, and a first display unit 12a that transmits the light emitted by the first light source 11a and displays a real image RI of a display image formed in front of a driver DR (passenger); a second light source 11b that emits light in the visible wavelength range, for example, and a second display unit 12a that transmits the light emitted by the second light source 11b and displays a virtual image VI of a display image formed in front of the driver DR; The vehicle includes a second PGU 10b having a display unit 12b, a reflector 13 that reflects a first display light L11 representing an image displayed on the first display unit 12a and a second display light L22 representing an image displayed on the second display unit 12b toward a windshield WS (a light-transmitting member), and a control unit 15 that controls the display contents of the first display unit 12a and the second display unit 12b and controls switching between the first PGU 10a and the second PGU 10b, and these are housed in a housing 16. The housing 16 is provided with an opening 17 (exit port) through which the first display light L11 and the second display light L22 are emitted, and a cover glass 18 is disposed in the opening 17 to protect the interior. The driver DR is an example of a passenger, the windshield WS is an example of a light-projecting member, and the opening 17 is an example of an exit port.

[0011] As shown in FIG. 1, the control unit 15 may be configured so that the first PGU 10a and the second PGU 10b are controlled by a single control unit 15, or the first PGU 10a and the second PGU 10b may each have their own control unit, and the control unit 15 may control these control units in cooperation with each other.

[0012] The HUD device 1 is disposed below a windshield WS of a vehicle C (for example, inside an instrument panel), and emits a first display light L11 and a second display light L22, which are projected onto the windshield WS. The first display light L11 is generated by a first light source 11a and a first display unit 12a inside the HUD device 1, and the second display light L22 is generated by a second light source 11b and a second display unit 12b inside the HUD device 1. The first display light L11 emitted from the first display unit 12a and the second display light L22 emitted from the second display unit 12b travel along the reflector 13 and are emitted from an opening 17 in a housing 16 through a cover glass 18. The driver DR of vehicle C can see a real image RI in front of the windshield WS by viewing the first display light L11 reflected by the windshield WS (real image display state), and can see a virtual image VI in the back of the windshield WS by viewing the second display light L22 reflected by the windshield WS (virtual image display state).

[0013] The virtual image VI in FIG. 1 displays information that is highly necessary to draw the driver DR's attention, such as vehicle information such as the speed and engine RPM of the vehicle C, route guidance displays such as turn-by-turn directions and maps, blind spot indicators, and warning displays such as speed limit exceeding warnings, on the other side of the windshield WS as viewed from the driver DR. The real image RI in FIG. 1 displays, for example, entertainment content, assistants and agents supporting the driver DR, and characters representing them, on the front side of the windshield WS as viewed from the driver DR. These displays provide a driving environment that reduces the need to move the driver's viewpoint and adjust the focal length of the eyes. The virtual image VI and real image RI include background portions as well as characters and icons indicating this information, and are, for example, approximately rectangular in shape when viewed in a planar view from the driver DR.

[0014] In the first PGU 10a, the first light source 11a is, for example, a light-emitting diode mounted on a wiring board that emits light in the visible wavelength range and emits white light. The first display unit 12a is provided closer to the opening 17 along the optical path than the first light source 11a, and has a TFT-type first display element (not shown in FIG. 1) that forms first display light L11 that displays an arbitrary image in accordance with a control signal sent from the control unit 15.

[0015] In the second PGU 10b, the second light source 11b is, for example, a light-emitting diode mounted on a wiring board that emits light in the visible wavelength range and emits white light. The second display unit 12b is provided closer to the opening 17 along the optical path than the second light source 11b, and has a TFT-type second display element (not shown in FIG. 1) that forms second display light L22 that displays an arbitrary image in accordance with a control signal sent from the control unit 15.

[0016] In addition to the above, in the first PGU 10a and the second PGU 10b, optical components such as a condenser lens, a lenticular lens, a diffusion plate, and a polarizing plate may be arranged at any position downstream of the first light source 11a and the second light source 11b, respectively.

[0017] In FIG. 1, the reflecting unit 13 includes a first correcting mirror 1310 that reflects the first display light L11 emitted from the first display unit 12a toward the second correcting mirror 1320, a second correcting mirror 1320 that reflects the first display light L11 emitted from the first correcting mirror 1310 toward the concave mirror 1330, and a concave mirror 1330 that reflects the first display light L11 reflected and folded by the first correcting mirror 1310 and the second correcting mirror 1320 and the second display light L22 that has passed through the second correcting mirror 1320 toward the opening 17.

[0018] The first correcting mirror 1310 and the second correcting mirror 1320 have mirrored surfaces and are formed into complex free-form shapes to correct distortion of the image viewed by the driver DR. The second correcting mirror 1320 is, for example, a half mirror, and transmits the second display light L22 representing the virtual image VI displayed on the second display unit 12b. The second display light L22 transmitted through the second correcting mirror 1320 is directly incident on the concave mirror 1330. The concave mirror 1330 is rotatably installed and rotates to match the position of the driver DR's eyes, freely changing the emission direction of the first display light L11 and the second display light L22 and adjusting the position of the image. In particular, it may be desirable to have different angles of the display surface when the first display light L11 displays a real image RI and when the second display light L22 displays a virtual image VI (for example, displaying the virtual image VI as if it is inclined relative to the road surface, and displaying the real image RI as if it is standing perpendicular to the road surface), and by performing such adjustments using rotational drive, it is possible to display the display images at angles appropriate for the real image RI and virtual image VI, respectively.

[0019] The first correcting mirror 1310 is disposed closer to the opening 17 than the first PGU 10a along the optical path of the first display light L11, and is disposed closer to the first PGU 10a than a first optical focal point F1 of an imaging optical system including the windshield WS, the second correcting mirror 1320, and the concave mirror 1330. The second display unit 12b of the second PGU 10b is disposed closer to the opening 17 than a second optical focal point F2 of the imaging optical system including the windshield WS and the concave mirror 1330 along the optical path of the second display light L22. When the first correcting mirror 1310, the second correcting mirror 1320, the concave mirror 1330, and the windshield WS are considered to be a single optical system, the position of the first display unit 12a is inside the focal length of that optical system (between the first correcting mirror 1310 and the second correcting mirror 1320 in the present disclosure). Furthermore, when the second correcting mirror 1320, the concave mirror 1330, and the windshield WS are considered to be one optical system, the position of the second display unit 12b is outside the focal length of that optical system.

[0020] With this configuration, when the first light source 11a is turned on, that is, when the first PGU 10a is ON, the first display light L11 emitted from the first PGU 10a is reflected by the first correcting mirror 1310, the second correcting mirror 1320, the concave mirror 1330, and the windshield WS, allowing the driver DR to view a real image RI on the inside of the vehicle through the windshield WS. Also, when the second light source 11b is turned on, that is, when the second PGU 10b is ON, the second display light L22 emitted from the second PGU 10b passes through the second correcting mirror 1320 and is reflected by the concave mirror 1330 and the windshield WS, allowing the driver DR to view a virtual image VI on the outside of the vehicle through the windshield WS.

[0021] Although countless rays of light are actually emitted from the first display unit 12a and the second display unit 12b, for ease of explanation, the light emitted from the center of each of the first display unit 12a and the second display unit 12b and passing through the center of the eyebox is referred to as a representative ray and is indicated by the symbols L11 and L22. In Fig. 1, the representative ray emitted from the center of the first display unit 12a and the second display unit 12b is indicated by a solid line, the ray emitted from the upper end of the first display unit 12a and the second display unit 12b is indicated by a dashed-dotted line, and the ray emitted from the lower end of the first display unit 12a and the second display unit 12b is indicated by a dashed-dotted line.

[0022] The control unit 15 is configured with a computer including a CPU that executes various pre-stored programs while utilizing the temporary storage function of the memory, and a memory consisting of a storage device including RAM and ROM. The control unit 15 controls at least the first PGU 10a and the second PGU 10b in cooperation with each other, and controls switching between the real image RI and the virtual image VI by turning on / off the first light source 11a and the second light source 11b, as well as controlling the display content of the first display unit 12a and the second display unit 12b. The switching between the real image RI and the virtual image VI by the control unit 15 will be described in detail below.

[0023] 2 is a functional block diagram showing the configuration of the control unit 15 in the HUD device 1 according to this embodiment. The control unit 15 includes a detection unit 21 that detects an indication of the occurrence of a trigger condition for switching between a virtual image VI and a real image RI based on external information 25 input from the outside, a switching processing unit 22 that switches from the display state of the virtual image VI to the display state of the real image RI (i.e., turns off the second PGU 10b and turns on the first PGU 10a) or switches from the display state of the real image RI to the display state of the virtual image VI (i.e., turns off the first PGU 10a and turns on the second PGU 10b) based on the detection information of the detection unit 21, and a display control unit 23 that controls the display contents of the first display unit 12a and the second display unit 12b based on information input from various devices 30 including memories and the like.

[0024] Trigger conditions for switching from the display state of the real image RI to the display state of the virtual image VI include, for example, when switching from automatic driving mode to manual driving mode, when the state of the seat in which the driver DR sits transitions from a reclined state to a normal state (the seat state when driving), when a traffic light changes from red to green (i.e., when the vehicle C transitions from a parked state to a driving state), when transitioning from driving on a highway to driving on an ordinary road (i.e., when, for example, the ACC (adaptive cruise control) transitions from an ON state to an OFF state), etc. Signs of the occurrence of these trigger conditions are detected by the detection unit 21.

[0025] More specifically, for example, the detection unit 21 acquires information about changes in the state of the seat that change depending on the manual driving mode and the automatic driving mode (for example, information about the reclining angle of the backrest) as external information 25, and detects the timing of switching from the automatic driving mode to the manual driving mode and changes in the position of the iris (sign detection processing). The switching processing unit 22 switches from the display state of the real image RI to the display state of the virtual image VI based on the detection result of the detection unit 21. At this time, the switching processing unit 22 performs processing for switching between the display of the real image RI and the display of the virtual image VI from the time the detection unit 21 detects the start of the transition operation from the reclining state to the normal state until the end of the transition operation.

[0026] Furthermore, for example, the detection unit 21 acquires, as the external information 25, imaging information capturing the state of a traffic light in a direction different from the traveling direction of the vehicle C when the light is red, and detects the timing when the traffic light in the traveling direction will turn green from the acquired imaging information by image processing (signal identification processing, sign detection processing). The switching processing unit 22 switches the display state from the real image RI to the virtual image VI based on the detection result of the detection unit 21. The detection unit 21 may also directly receive, as the external information 25, information transmitted from a traffic light in the traveling direction of the vehicle C, and detect the timing when the traffic light will switch based on the received information. In this case, the switching processing unit 22 performs a process of switching between the real image RI display and the virtual image VI display during a period from a predetermined time (for example, several seconds to several tens of seconds) before the timing of the traffic light switch detected by the detection unit 21 to the completion of the traffic light switch.

[0027] For example, when the detection unit 21 detects that the traffic light in the travel direction is red and also detects that the vehicle C is stopped, the switching processing unit 22 may perform control to switch from the display state of the virtual image VI to the display state of the real image RI. At this time, it is desirable that the display control unit 23 (described later) perform control to display, as the real image RI, the remaining distance and required time to the destination, and information that could not be referred to during driving operations (for example, useful information about nearby gas stations, restaurants, parking lots, tourist information, etc.).

[0028] Furthermore, for example, the detection unit 21 acquires information on the traveling position and traveling direction of the vehicle C (including information on the destination) from a car navigation system, a GPS system, or an ETC on-board device as external information 25, and detects the timing when the traveling state of the vehicle C transitions from traveling on an expressway to traveling on an ordinary road based on the acquired external information 25 (road identification processing, sign detection processing). The switching processing unit 22 switches from the display state of the real image RI to the display state of the virtual image VI based on the detection result of the detection unit 21. At this time, the switching processing unit 22 performs switching processing between the display of the real image RI and the display of the virtual image VI from a predetermined time (for example, several seconds to several tens of seconds) before the timing of the transition of the traveling state detected by the detection unit 21 until the end of the transition of the traveling state.

[0029] In other words, the detection unit 21 and the switching processing unit 22 detect signs of the occurrence of a trigger condition in the display state of the real image RI, and switch from the display state of the real image RI to the display state of the virtual image VI before the operation of the trigger condition ends, and the virtual image VI is displayed when the operation of the trigger condition ends.

[0030] In addition, when displaying the real image RI and the virtual image VI, only one of them may be displayed, or both may be displayed simultaneously, and in particular, as will be described later, they may be displayed simultaneously during the switching process by the switching processing unit 22.

[0031] Furthermore, although the above description has been given of switching from the display state of the real image RI to the display state of the virtual image VI, the detection unit 21 and the switching processing unit 22 may also function when switching from the display state of the virtual image VI to the display state of the real image RI. That is, control may be performed such that a sign of the occurrence of a trigger condition is detected in the display state of the virtual image VI, and the display state of the virtual image VI is switched to the display state of the real image RI before the operation of the trigger condition ends, and the real image RI is displayed when the operation of the trigger condition ends. In this case, the trigger condition is assumed to be the opposite of the above-described case (i.e., switching from manual driving to automatic driving, transition of the seat from the normal state to the reclining state, switching from a green light to a red light, or transition from driving on an ordinary road to driving on an expressway).

[0032] 2, a display control unit 23 outputs control signals to the first display unit 12a and the second display unit 12b to generate light representing a figure of any shape based on information sent from various devices 30, such as a vehicle speed sensor, a navigation device, a RADAR (Radio Detecting and Ranging), or a LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), and content information pre-registered in a memory, etc. Then, the first PGU 10a and the second PGU 10b display desired display images, respectively.

[0033] Next, switching control between the real image RI and the virtual image VI by the switching processing unit 22 will be described. Note that the following description will mainly focus on the characteristics of switching control when switching from real image RI display to virtual image VI display. Fig. 3 is a diagram showing processing when the switching processing unit 22 in the HUD device 1 according to this embodiment simultaneously switches between the real image RI and the virtual image VI. Fig. 3(A) is a diagram showing the switching state between the automatic driving mode and the manual driving mode over time, Fig. 3(B) is a diagram showing the switching state of the ON / OFF state of the second PGU 10b that displays the virtual image VI over time, and Fig. 3(C) is a diagram showing the switching state of the ON / OFF state of the first PGU 10a that displays the real image RI over time.

[0034] As shown in FIG. 3, in the manual driving mode, the second PGU 10b is turned ON to allow the driver DR to view the virtual image VI, and in the automatic driving mode, the first PGU 10a is turned ON to allow the driver DR to view the real image RI. Then, as shown in FIGS. 3B and 3C, when the detection unit 21 detects a sign of the trigger condition (when the operation of the trigger condition starts), the switching processing unit 22 turns ON the second PGU 10b to display the virtual image VI and simultaneously turns OFF the first PGU 10a to hide the real image RI. When the operation of the trigger condition ends, the driver DR is able to view the virtual image VI. In this case, the driver DR is always able to view either one of the displayed images during the switching operation from the real image RI display to the virtual image VI display.

[0035] In the case of Figure 3, the real image RI display and the virtual image VI display are switched at the same time as the trigger condition operation starts, but the real image RI display and the virtual image VI display may be switched at any timing while the trigger condition is in operation.

[0036] 4A and 4B are diagrams showing the process when the switching processing unit 22 in the HUD device 1 according to this embodiment switches between a real image RI and a virtual image VI over a predetermined time period. Fig. 4A is a diagram showing the switching state between the automatic driving mode and the manual driving mode over time, Fig. 4B is a diagram showing the switching state of the ON / OFF state of the second PGU 10b that displays the virtual image VI over time, and Fig. 4C is a diagram showing the switching state of the ON / OFF state of the first PGU 10a that displays the real image RI over time.

[0037] In FIG. 4, as in the case of FIG. 3, in the manual driving mode, the second PGU 10b is turned on to allow the driver DR to view the virtual image VI, and in the automatic driving mode, the first PGU 10a is turned on to allow the driver DR to view the real image RI. Then, as shown in FIGS. 4(B) and 4(C), when the detection unit 21 detects a sign of the trigger condition (when the operation of the trigger condition starts), the switching processing unit 22 turns on the second PGU 10b while gradually increasing the brightness over a predetermined time (first predetermined time: the time from the sign detection to the end of the trigger condition operation), and turns off the first PGU 10a while gradually decreasing the brightness over a predetermined time (first predetermined time). As in the case of FIG. 3, when the operation of the trigger condition ends, the driver DR is able to view the virtual image VI. In this case, the driver DR is able to simultaneously view the real image RI and the virtual image VI during the switching operation from the real image RI display to the virtual image VI display.

[0038] In the case of Figure 4, the control to switch between the real image RI display and the virtual image VI display starts as soon as the operation of the trigger condition starts, and the control to switch between the real image RI display and the virtual image VI display ends as soon as the operation of the trigger condition ends. However, while the trigger condition is in operation, the control to switch between the real image RI display and the virtual image VI display may be configured to be performed at any timing and at any time interval.

[0039] 5A and 5B are diagrams showing processing when the switching processing unit 22 in the HUD device 1 according to this embodiment switches between a real image RI and a virtual image VI at different timings. Fig. 5A is a diagram showing the switching state between the automatic driving mode and the manual driving mode over time, Fig. 5B is a diagram showing the switching state of the ON / OFF state of the second PGU 10b that displays the virtual image VI over time, and Fig. 5C is a diagram showing the switching state of the ON / OFF state of the first PGU 10a that displays the real image RI over time.

[0040] In FIG. 5, as in FIGS. 3 and 4, in the manual driving mode, the second PGU 10b is turned ON to allow the driver DR to view the virtual image VI, and in the automatic driving mode, the first PGU 10a is turned ON to allow the driver DR to view the real image RI. Then, as shown in FIGS. 5(B) and 5(C), when the detection unit 21 detects a sign of the trigger condition (when the operation of the trigger condition starts), the switching processing unit 22 turns OFF the first PGU 10a to hide the real image RI. Then, after a predetermined time (a third predetermined time: a time shorter than the time between the detection of the sign and the end of the operation of the trigger condition) has elapsed and before the operation of the trigger condition ends, the second PGU 10b is turned ON to display the virtual image VI. As in FIGS. 3 and 4, when the operation of the trigger condition ends, the driver DR can view the virtual image VI. In this case, there will be a period during which the driver DR cannot visually recognize either the real image RI or the virtual image VI during the switching operation from the real image RI display to the virtual image VI display.

[0041] In FIG. 5, the real image RI may be hidden at any timing while the trigger condition is in operation, and the virtual image VI may be displayed thereafter.

[0042] The switching processing unit 22 performs switching control when there is no period during which the real image RI and the virtual image VI are simultaneously viewed, as shown in FIGS. 3 and 5 (hereinafter referred to as "first switching control"), or when there is a period during which the real image RI and the virtual image VI are simultaneously viewed, as shown in FIG. 4 (hereinafter referred to as "other switching control"). These switching controls may be selected depending on the overlap state of the virtual image VI and the real image RI in the driver's field of view, based on the relationship between the display positions of the virtual image VI and the real image RI and the position of the driver's iris. FIG. 6 is a diagram showing the positions at which the virtual image VI and the real image RI are displayed in the HUD device 1 according to this embodiment. FIG. 6(A) shows a positional relationship in which the virtual image VI and the real image RI do not overlap as viewed from the driver DR, and FIG. 6(B) shows a positional relationship in which the virtual image VI and the real image RI overlap as viewed from the driver DR.

[0043] A typical example of a positional relationship in which the virtual image VI and the real image RI shown in Fig. 6(A) do not overlap is when the seat position does not change depending on whether the driving mode is automatic or manual. On the other hand, a typical example of a positional relationship in which the virtual image VI and the real image RI overlap is when the seat position changes depending on whether the driving mode is automatic or manual. That is, in the case of Fig. 6(B), by changing the seat position so that the seat is reclined in automatic driving mode and reclined in manual driving mode, the virtual image VI and the real image RI overlap.

[0044] In other words, when the virtual image VI and the real image RI are in a positional relationship where they do not overlap when viewed from the driver DR, as in Figure 6(A), another switching control is performed in which there is a period during which the real image RI and the virtual image VI are visible simultaneously, and when the virtual image VI and the real image RI are in a positional relationship where they overlap when viewed from the driver DR, as in Figure 6(B), one switching control is performed in which there is no period during which the real image RI and the virtual image VI are visible simultaneously.

[0045] Next, the operation of the control unit 15 for transitioning from a real image RI display state to a virtual image VI display state when a trigger condition is detected in the control for displaying a real image RI in the autonomous driving mode and a virtual image VI in the manual driving mode will be described. FIG. 7 is a flowchart showing the operation of the control unit 15 when a trigger condition is detected in the HUD device according to this embodiment. First, the detection unit 21 detects the occurrence of the trigger condition based on external information 25 (S1) (sign detection process). The switching processing unit 22 determines whether the current driving state is in the autonomous driving mode and the real image RI is being displayed (S2). If the real image RI is being displayed in the autonomous driving mode, the first PGU 10a is turned off and the second PGU 10b is turned on (S3) (switching process) according to the control of any one of FIGS. 3 to 5. The switching processing unit 22 completes the display of the virtual image VI by the second PGU 10b until the operation of the trigger condition is completed (S4) (switching process). Then, when the vehicle C enters a driving state in the manual driving mode, the virtual image VI continues to be displayed during the manual driving mode (S5), and the process ends.

[0046] 4 and 5, the control performed by the switching processing unit 22 when switching from the real image RI display state to the virtual image VI display state has been described in detail, but similar control may also be performed when switching from the virtual image VI display state to the real image RI display state. Fig. 8 is a diagram showing a second process when the switching processing unit 22 in the HUD device 1 according to this embodiment switches between the real image RI and the virtual image VI over a predetermined time. Fig. 8(A) is a diagram showing the switching state between the automatic driving mode and the manual driving mode over time, Fig. 8(B) is a diagram showing the switching state of the ON / OFF state of the second PGU 10b that displays the virtual image VI over time, and Fig. 8(C) is a diagram showing the switching state of the ON / OFF state of the first PGU 10a that displays the real image RI over time.

[0047] In FIG. 8, in the manual driving mode, the second PGU 10b is turned ON to allow the driver DR to view the virtual image VI, and in the automatic driving mode, the first PGU 10a is turned ON to allow the driver DR to view the real image RI. As shown in FIGS. 8B and 8C, when the detection unit 21 detects a sign of the trigger condition (when the operation of the trigger condition starts), the switching processing unit 22 turns off the second PGU 10b while gradually decreasing the brightness over a predetermined time (second predetermined time: the time from the sign detection to the end of the trigger condition operation), and turns on the first PGU 10a while gradually increasing the brightness over a predetermined time (second predetermined time). When the operation of the trigger condition ends, the driver DR is able to view the real image RI. In this case, the driver DR is able to simultaneously view the real image RI and the virtual image VI during the switching operation from the virtual image VI display state to the real image RI display state. The predetermined time shown in FIG. 4 (first predetermined time) and the predetermined time shown in FIG. 8 (second predetermined time) may be the same or different.

[0048] 9 is a second diagram showing processing when the switching processing unit 22 in the HUD device 1 according to this embodiment switches between the real image RI and the virtual image VI at different timings. Fig. 9(A) is a diagram showing the switching state between the automatic driving mode and the manual driving mode over time, Fig. 9(B) is a diagram showing the switching state of the ON / OFF state of the second PGU 10b that displays the virtual image VI over time, and Fig. 9(C) is a diagram showing the switching state of the ON / OFF state of the first PGU 10a that displays the real image RI over time.

[0049] In FIG. 9 , in the manual driving mode, the second PGU 10b is turned ON to allow the driver DR to view the virtual image VI, and in the automatic driving mode, the first PGU 10a is turned ON to allow the driver DR to view the real image RI. Then, as shown in FIGS. 9B and 9C , when the detection unit 21 detects a sign of the trigger condition (when the operation of the trigger condition starts), the switching processing unit 22 turns OFF the second PGU 10b to hide the virtual image VI. Then, after a predetermined time (a fourth predetermined time: a time shorter than the time between the detection of the sign and the end of the operation of the trigger condition) has elapsed and before the operation of the trigger condition ends, the first PGU 10a is turned ON to display the real image RI. At the time the operation of the trigger condition ends, the driver DR is able to view the real image RI. In this case, during the switching operation from the virtual image VI display state to the real image RI display state, the driver DR experiences a period in which neither the real image RI nor the virtual image VI can be viewed. Note that the predetermined time (third predetermined time) shown in Fig. 5 and the predetermined time (fourth predetermined time) in Fig. 9 may be the same time or different times. Also, Fig. 9 describes control when switching between the virtual image VI display state and the real image RI display state in conjunction with a transition from the manual driving mode to the automatic driving mode, but in consideration of safety, it is desirable that the conditions for turning on the first PGU 10a and displaying the real image RI include the vehicle C being stopped.

[0050] As described above, the HUD device 1 according to this embodiment is provided in a vehicle C equipped with a seat for a driver DR and a windshield WS, and when the first display light L11 and the second display light L22 are emitted from the opening 17 toward the windshield WS to allow the driver DR to view the display images represented by the first display light L11 and the second display light L22, the HUD device 1 can switch between a virtual image display state in which a virtual image VI of the display image is visible and a real image display state in which a real image RI of the display image is visible upon the occurrence of a predetermined trigger condition. The HUD device 1 includes display elements, a first display unit 12a and a second display unit 12b that transmit light emitted from the first light source 11a and the second light source 11b and display a display image, and a display screen displayed on the first display unit 12a and the second display unit 12b. The control unit 15 includes a reflector 13 that reflects light representing an image toward the windshield WS, and a controller 15. The controller 15 executes a sign detection process S1 that detects signs of the occurrence of a trigger condition, and switching processes S3 and S4 that switch from the virtual image VI display state to the real image RI display state or from the real image RI display state to the virtual image VI display state prior to the occurrence of the trigger condition when a sign is detected in the sign detection process. Therefore, by switching between the real image RI display state and the virtual image VI display state in advance prior to the occurrence of the trigger condition, rather than switching between the real image RI display state and the virtual image VI display state after the action that constitutes the trigger condition occurs, optimal control can be performed that is suited to the preparatory action (shifting one's line of sight) of the driver DR. This also has the effect of encouraging the driver DR to take the preparatory action itself.

[0051] Furthermore, in the HUD device 1 according to this embodiment, the control unit 15 switches from the virtual image VI display state to the real image RI display state in the switching processes S3 and S4 based on the detection of signs of a transition from manual driving mode to automatic driving mode as a trigger condition, and switches from the real image RI display state to the virtual image VI display state based on the detection of signs of a transition from automatic driving mode to manual driving mode as a trigger condition. Therefore, by switching the real image RI / virtual image VI in advance of the switching between automatic driving mode and manual driving mode, optimal control can be performed that is suited to the preparatory actions of the driver DR (shifting one's gaze closer before the vehicle C starts moving in automatic driving, and shifting one's gaze further away before the vehicle C starts moving in manual driving).

[0052] Furthermore, in the HUD device 1 according to this embodiment, the control unit 15 switches from the virtual image VI display state to the real image RI display state or from the real image RI display state to the virtual image VI display state in the switching processes S3 and S4 based on the detection of a sign of a change in the seat state as a trigger condition that changes depending on the manual driving mode and the automatic driving mode. Therefore, by switching between the real image RI display state and the virtual image VI display state in advance of the change in the seat state, optimal control can be performed that is suited to the preparatory action (shifting of the driver's line of sight) of the driver DR. This is particularly effective when the line of sight (iris) of the driver DR changes due to a change in the seat state.

[0053] Furthermore, in the HUD device 1 according to the present embodiment, the control unit 15 executes a signal identification process for identifying the operational behavior of a traffic light related to the travel of the vehicle C. In the switching processes S3 and S4, the control unit 15 switches from the virtual image VI display state to the real image RI display state in response to the detection of a sign of the traffic light transitioning to a red light, which serves as a trigger condition, based on the identification result of the signal identification process. Furthermore, the control unit 15 switches from the real image RI display state to the virtual image VI display state in response to the detection of a sign of the traffic light transitioning to a green light, which serves as the trigger condition, based on the identification result of the signal identification process. Therefore, by switching the real image RI / virtual image VI in advance of the red / green light transition, optimal control can be performed in accordance with the driver DR's preparatory behavior (such as shifting one's gaze to a distant location before the green light turns green or shifting one's gaze to a nearby location before the red light turns red). Furthermore, for example, information that cannot be displayed using the virtual image VI while traveling on a green light or that is not desirable to display (e.g., surrounding environment information, store information, etc.) can be displayed using the real image RI during a short break when the vehicle stops traveling due to a red light, thereby improving convenience. Furthermore, safety can be improved by erasing the information displayed as a real image RI while the vehicle is stopped at a red light, before the vehicle starts moving again at a green light and the information is displayed as a virtual image VI.

[0054] Furthermore, in the HUD device 1 according to this embodiment, the control unit 15 executes a road identification process to identify the type of road on which the vehicle C is traveling, and in the switching processes S3 and S4, the control unit switches from the virtual image VI display state to the real image RI display state based on the detection of a sign of entering an expressway as a trigger condition, and switches from the real image RI display state to the virtual image VI display state based on the detection of a sign of exiting an expressway as a trigger condition. Therefore, by switching between the real image RI display state and the virtual image VI display state in advance of entering / exiting an expressway, optimal control can be performed that is suited to the preparatory actions of the driver DR (shifting one's gaze closer before entering the expressway and switching to automatic driving mode, and shifting one's gaze farther away before switching to manual driving mode when exiting the expressway).

[0055] Furthermore, in the HUD device 1 of this embodiment, in the switching processes S3 and S4, when switching from the real image RI display state to the virtual image VI display state, the control unit 15 starts displaying the virtual image VI and stops displaying the real image RI after a first predetermined time has elapsed, and when switching from the virtual image VI display state to the real image RI display state, starts displaying the real image RI and stops displaying the virtual image VI after a second predetermined time has elapsed, thereby reducing the psychological burden on the driver DR associated with switching between the real image RI display state and the virtual image VI display state.

[0056] Furthermore, in the HUD device 1 according to this embodiment, the first display unit 12a, the second display unit 12b, and the reflector 13 are arranged so that the viewing positions of the virtual image VI and the real image RI within the field of view of the driver DR do not overlap with each other. Therefore, when the real image RI and the virtual image VI are displayed simultaneously, the respective display images can be viewed comfortably without interfering with each other.

[0057] Furthermore, in the HUD device 1 of this embodiment, in the switching processes S3 and S4, when switching from the real image RI display state to the virtual image VI display state, the control unit 15 stops displaying the real image RI and starts displaying the virtual image VI after a third predetermined time has elapsed, and when switching from the virtual image VI display state to the real image RI display state, the control unit 15 stops displaying the virtual image VI and starts displaying the real image RI after a fourth predetermined time has elapsed, so that the driver DR can clearly recognize that the real image RI / virtual image VI is switching.

[0058] Furthermore, in the HUD device 1 according to this embodiment, the first display unit 12a, the second display unit 12b, and the reflector 13 are arranged so that the viewing position of the virtual image VI and the viewing position of the real image RI overlap each other within the field of view of the driver DR. Therefore, when switching control is performed so that the real image RI and the virtual image VI are not displayed simultaneously, even if the display images overlap in position, they can be viewed comfortably without interfering with each other.

[0059] (Second embodiment of the present invention) The HUD device 1 according to this embodiment will be described with reference to Figures 10 and 11. The HUD device 1 according to this embodiment is configured to switch between a real image RI display state and a virtual image VI display state using a single PGU 10. Note that in this embodiment, descriptions that overlap with those in the first embodiment will be omitted.

[0060] FIG. 10 is a diagram showing a configuration in which a virtual image VI is generated in the HUD device 1 according to this embodiment, and FIG. 11 is a diagram showing a configuration in which a real image RI is generated in the HUD device 1 according to this embodiment. In FIGS. 10 and 11, the HUD device 1 includes a light source 11 that emits white light, for example, a light-emitting diode (LED) that emits light in the visible wavelength range and is mounted on a wiring board; a display unit 12 that generates an image using the light incident from the light source 11 and switches the polarization of the emitted light between a first polarization and a second polarization; a reflector 13 that reflects display light L representing the image displayed on the display unit 12 (display light L1 representing the virtual image VI in FIG. 10 , and display light L2 representing the real image RI in FIG. 11 ) toward the windshield WS; and a control unit 15 that controls the display content of the display unit 12 and switches between the first polarization and the second polarization. These components are housed in a housing 16. The housing 16 is provided with an opening 17 through which the display light L is emitted, and a cover glass 18 is disposed in the opening 17 to protect the interior.

[0061] Regarding the configuration of the light source 11 and the display unit 12, the display unit 12 is provided closer to the exit along the optical path than the light source 11. The display unit 12 includes, for example, a TFT (Thin Film Transistor) type display element, and a switching element that is provided closer to the exit along the optical path than the display element and switches the polarization of the emitted display light L between first polarization and second polarization that are different from each other.

[0062] For example, the first polarized light may be S polarized light and the second polarized light may be P polarized light, or vice versa. In addition, the first polarized light and the second polarized light are not limited to S polarized light and P polarized light, as long as the polarization angles of the first polarized light and the second polarized light are different, and it is desirable that the polarization angles differ by at least 22.5 degrees, for example.

[0063] Furthermore, as shown in Figures 10 and 11, it is desirable that the display unit 12 be arranged at an angle with respect to the axial direction of the light rays of the display light L in order to eliminate stray light (light leaking from the light source 11) and external light (light coming in from outside) from the optical path of the display light L.

[0064] The display element forms light that represents a figure of any shape in accordance with a signal sent from the control unit 15, and the switching element extracts only light of a specific polarization, specifically the first polarization or second polarization described above, from the light beams emitted from the display element and switches between them. The switching element is connected to the switching processing unit 22 of the control unit 15 in Figure 2, and switches the polarization in accordance with a signal sent from the switching processing unit 22.

[0065] The switching of polarization by the switching element may be performed by electrical processing, or the polarization may be switched by arranging a polarizing plate or a wave plate on the exit side of the display element and physically rotating the central axis at a predetermined angle with the optical axis direction as the central axis. In either case, the switching of polarization is performed under the control of the switching processing unit 22.

[0066] 10 and 11, the reflecting unit 13 includes a first mirror 131, a second mirror 132, and a third mirror 133, each of which is a concave mirror. The first mirror 131 reflects display light L1, which is a first polarization, and transmits display light L2, which is a second polarization. The second mirror 132 reflects display light L2 that transmits through the first mirror 131. The display lights L1 and L2 reflected by the first mirror 131 and the second mirror 132 are guided to the third mirror 133, reflected by the third mirror 133, and emitted to the windshield WS, allowing the driver DR to view the respective display images.

[0067] In reality, countless rays of light are emitted from the display unit 12, but for ease of explanation, the light emitted from the center of the display unit 12 and passing through the center of the eyebox is referred to as the representative ray and is indicated by the symbol L. In addition, in Figures 10 and 11, the representative ray emitted from the center of the display unit 12 is indicated by a solid line, the ray emitted from the upper end of the display unit 12 is indicated by a dashed line, and the ray emitted from the lower end of the display unit 12 is indicated by a dashed line.

[0068] 11, since the first mirror 131 is a mirror that transmits the display light L2, the display light L2 reflected by the second mirror 132 can also be transmitted from the rear side where the second mirror 132 is located to the front side. That is, as shown in Fig. 11, the display light L2 that has transmitted through the first mirror 131 is reflected by the second mirror 132, transmitted through the first mirror 131 again, and guided to the third mirror 133. This makes it possible to arrange the second mirror 132 close to the rear side of the first mirror 131, thereby preventing the housing 16 from becoming large.

[0069] Here, for example, the first polarized light is S polarized light (S polarized light relative to the first mirror 131), the second polarized light is P polarized light (P polarized light relative to the first mirror 131), the first mirror 131 is a mirror that reflects S polarized light toward the first mirror 131 and transmits P polarized light, and the second mirror 132 is a mirror that reflects P polarized light toward the first mirror 131 and transmits S polarized light. In this configuration, the display light L1, which is S polarized light, is reflected by the first mirror 131 and guided to the third mirror 133. The display light L2, which is P polarized light, transmits the first mirror 131, is reflected by the second mirror 132, and is guided to the third mirror 133. By setting such a configuration of the reflector 13 and the polarizations of the display lights L1 and L2, it is possible for the display lights L1 and L2 to generate different display images.

[0070] A display image represented by display light L1 in Fig. 10 and a display image represented by display light L2 in Fig. 11 will be specifically described. As shown in Fig. 11, the second mirror 132 is a mirror having a concave shape, and has a radius of curvature R2 such that, when the second mirror 132, the third mirror 133, and the windshield WS are considered as a single optical system, the position of the display unit 12 is in a second state outside the focal length of the optical system (on the front side with respect to the display light L). As a result, when light of the second polarization is emitted, the light reflected by the second mirror 132, the third mirror 133, and the windshield WS is visually recognized as a real image RI by the driver DR.

[0071] As shown in FIG. 10 , the first mirror 131 also has a concave shape, but has a radius of curvature R1 (R1>R2) larger than the radius of curvature R2 of the second mirror 132. When the first mirror 131, the third mirror 133, and the windshield WS are considered as a single optical system, the radius of curvature R1 is such that the display unit 12 is positioned inside the focal length of the optical system (at the rear end with respect to the display light L). This is because, when the radius of curvature R1 of the concave mirror is large, the focal length becomes farther from the mirror, and when the radius of curvature R1 is small, the focal length becomes closer to the mirror. Therefore, the radius of curvature R1 of the first mirror 131, which makes the focal length farther, is larger. As a result, when light of the first polarization is emitted, the light reflected by the first mirror 131, the third mirror 133, and the windshield WS is visually recognized by the driver DR as a virtual image VI. Note that the optical focus is indicated by F in FIGS. 10 and 11 .

[0072] That is, for example, when it is desired that a virtual image VI be viewed from the driver DR on the far side of the windshield WS, the switching element of the display unit 12 switches the display light L to be emitted as display light L1, which is a first polarization, and the display image represented by the display light L1 is displayed on the windshield WS by an imaging optical system consisting of the first mirror 131, the third mirror 133, and the windshield WS. Also, when it is desired that a real image RI be viewed from the driver DR on the near side of the windshield WS, the switching element of the display unit 12 switches the display light L to be emitted as display light L2, which is a second polarization, and the display image represented by the display light L2 is displayed on the windshield WS by an imaging optical system consisting of the second mirror 132, the third mirror 133, and the windshield WS.

[0073] In Figures 10 and 11, the first mirror 131 is described as a mirror having a concave shape, but if the first mirror 131, the third mirror 133, and the windshield WS are considered to be a single optical system, and the position of the display unit 12 satisfies the condition that it is located inside the focal length of that optical system (on the rear side with respect to the display light L), then the first mirror 131 may be a mirror having a flat shape or a mirror having a convex shape.

[0074] 10 and 11, the third mirror 133 is depicted as a mirror having a concave shape, but it may also be a mirror having a flat shape or a mirror having a convex shape, and since the display lights L1 and L2 are irradiated via the same third mirror 133 whether a virtual image VI or a real image RI is displayed, the third mirror 133 may have a shape without magnification.

[0075] Regarding the configuration of the control unit 15, in FIG. 2 of the first embodiment, the switching processing unit 22 is configured to switch between the first PGU 10a and the second PGU 10b based on the detection result of the detection unit 21. However, in this embodiment, the switching processing unit 22 controls the display unit 12 (the polarization direction of the switching element and the light amount of the light source 11) shown in FIGS. 10 and 11 based on the detection result of the detection unit 21. That is, the control unit 22 controls the display light L to be emitted as the first polarized light so that the virtual image VI is visible, and the control unit 15 controls the display light L to be emitted as the second polarized light so that the real image RI is visible. By configuring the control unit 15 in this manner, the functions and effects described in the first embodiment can be realized. However, in this embodiment, since the real image RI display state and the virtual image VI display state cannot be simultaneously realized, it is preferable to configure the control unit 15 not to perform switching control when there is a period in which the real image RI and the virtual image VI are simultaneously visible, as shown in FIG. 4 (i.e., other switching control). [Explanation of symbols]

[0076] C vehicle DR Driver F optical focus F1 1st optical focus F2 2nd optical focus L(L1,L2) Display light L11 1st display light L22 2nd display light VI Virtual Image RI real image R1,R2 radius of curvature WS Window Shield 1 HUD device 10 PGU 10a 1st PGU 10b 2nd PGU 11 Light source 11a 1st light source 11b Second light source 12 Display section 12a 1st display section 12b 2nd display section 13 Reflector 15 Control Unit 16 Case 17 Opening 18 Coverslips 21 Detection unit 22 Switching processing section 23 Display control unit 25 External Information 30 Various Devices 131 1st Mirror 132 Second Mirror 133 Third Mirror 1310 First correcting mirror 1320 Second corrector mirror 1330 concave mirror

Claims

1. A head-up display device is provided in a vehicle having a seat on which a passenger sits and a light-transmitting member, and when display light is emitted from an emission port toward the light-transmitting member to allow a display image represented by the display light to be viewed, the head-up display device is capable of switching between a virtual image display state in which a virtual image of the display image is viewed and a real image display state in which a real image of the display image is viewed upon occurrence of a predetermined trigger condition, a display unit including a display element, which transmits light emitted from the light source and displays the display image; a reflecting section that reflects light representing the display image displayed on the display section toward the light-transmitting member; A control unit; and The control unit a sign detection process for detecting a sign of occurrence of the trigger condition; a switching process for switching from the virtual image display state to the real image display state or from the real image display state to the virtual image display state prior to occurrence of the trigger condition when the sign is detected in the sign detection process; A head-up display device characterized by executing the above.

2. In the switching process, the control unit switching from the virtual image display state to the real image display state based on detection of a sign of transition from the manual driving mode to the automatic driving mode as the trigger condition; Switching from the real image display state to the virtual image display state is performed based on detection of a sign of transition from the automatic driving mode to the manual driving mode as the trigger condition.

2. The head-up display device according to claim 1.

3. In the switching process, the control unit Switching from the virtual image display state to the real image display state or switching from the real image display state to the virtual image display state is performed based on detection of a sign of a change in the state of the seat as the trigger condition, which changes depending on whether the driving mode is manual or automatic.

2. The head-up display device according to claim 1.

4. The control unit further execute a signal identification process to identify the operational behavior of a traffic signal related to the running of the vehicle; In the switching process, switching from the virtual image display state to the real image display state in response to detection of a sign of the traffic light changing to a red light as the trigger condition based on an identification result of the signal identification processing; Switching from the real image display state to the virtual image display state is performed in response to detection of a sign of the traffic light transitioning to a green signal as the trigger condition based on the identification result of the signal identification processing.

2. The head-up display device according to claim 1.

5. The control unit further execute a road identification process for identifying the type of road on which the vehicle is traveling; In the switching process, switching from the virtual image display state to the real image display state based on detection of a sign of entering an expressway as the trigger condition; Switching from the real image display state to the virtual image display state is performed based on detection of a sign of exiting the expressway as the trigger condition.

2. The head-up display device according to claim 1.

6. In the switching process, the control unit When switching from the real image display state to the virtual image display state, the display of the real image is stopped after a first predetermined time has elapsed since the start of displaying the virtual image, and When switching from the virtual image display state to the real image display state, the display of the virtual image is stopped after a second predetermined time has elapsed since the start of displaying the real image.

2. The head-up display device according to claim 1.

7. The display unit and the reflector are The viewing position of the virtual image and the viewing position of the real image are arranged so as not to overlap each other within the field of view of the passenger.

7. The head-up display device according to claim 6.

8. In the switching process, the control unit When switching from the real image display state to the virtual image display state, the display of the real image is stopped and then a third predetermined time has elapsed, after which the display of the virtual image is started; When switching from the virtual image display state to the real image display state, the display of the virtual image is stopped and then the display of the real image is started after a fourth predetermined time has elapsed.

2. The head-up display device according to claim 1.

9. The display unit and the reflector are The virtual image and the real image are arranged so that their viewing positions overlap each other within the passenger's field of view.

9. The head-up display device according to claim 8.

Images