Head-up display device, method for controlling a head-up display device, and in-vehicle system

Abstract

This reduces the sense of discomfort caused by changes in brightness that occur when switching between real and virtual image displays. [Solution] The system includes a display unit 12 that transmits illumination light irradiated by a light source (backlight 11) to generate a first display light representing a virtual image and a second display light representing a real image; a polarization control element 122 that switches the polarization state of the first display light and the second display light; an imaging optical system that forms a virtual image with the first display light in the first polarization state in a first optical path and forms a real image by emitting the second display light in the second polarization state from the output port in a second optical path; and a control unit 15 that, upon receiving a display image switching signal, turns off the light source, switches between the first display light in the first polarization state and the second display light in the second polarization state, turns on the light source, and controls the system to form an image on the light-emitting member of the virtual image shown by the first display light or the real image shown by the second display light.

Description

Technical Field

[0001] The present invention relates to a head-up display device that allows a virtual image and a real image of a display image represented by display light to be visually recognized by emitting the display light from an emission port toward a light projection member, and the like.

Background Art

[0002] For example, Patent Document 1 includes a polarization reflection member (e.g., the first mirror 13(131) in FIG. 7) whose transmittance (reflectance) varies depending on the polarization state, and a second reflection member (the third mirror 13(133)) that reflects the display light transmitted through the polarization reflection member. The display light L1 in the first polarization state is emitted in a first optical path reflected on the surface of the polarization reflection member to form a virtual image VI, and the display light L2 in the second polarization state passes through the polarization reflection member and is emitted in a second optical path reflected by the second reflection member to form a real image. An imaging optical system, which is located inside the first focal point F1 of the imaging optical system in the first optical path and outside the second focal point F2 of the imaging optical system in the second optical path, and a single system of image generation unit PGU (Picture Generation Unit) that switches between the first and second polarization states, constitutes a head-up display device described in Patent Document 1 that was unpublished as of the filing date of the present application.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0006] , FIG. 7)

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the technology described in Patent Document 1, the displayed image is switched between a real image and a virtual image by changing the optical path. However, when the displayed image is switched between a real image and a virtual image, if the brightness of the backlight, which is the light source, is the same, it is known that the real image will be dimmer than the virtual image due to the characteristics of the illumination optical system such as the lens between the light source and the display (the light source used for the real image display illuminates the display so that the illumination light is focused on the display, while the light source used for the virtual image display illuminates the display so that the illumination light is divergent on the display). For this reason, in a head-up display device in which the light source is shared between the virtual image display and the real image display, when the displayed image is switched from a real image display to a virtual image display, or from a virtual image display to a real image display, the occupants of the vehicle, who are the viewers, may feel discomfort due to the difference in brightness between the real image display and the virtual image display.

[0005] Therefore, the object of the present invention is to provide a head-up display device, etc., that reduces the discomfort caused to the occupant, who is the viewer, by the difference in brightness that occurs when switching between a real image display and a virtual image display.

[0006] Other objects of the present invention will become apparent to those skilled in the art by referring to the embodiments and best embodiments described below, as well as the accompanying drawings. [Means for solving the problem]

[0007] The following are examples of embodiments of the present invention to facilitate understanding of its outline.

[0008] The first embodiment is a head-up display device having an emission port, which emits display light from the emission port toward a light-emitting member to allow the viewer to perceive a virtual image and a real image of a display image represented by the display light, comprising: a display that transmits illumination light irradiated by a light source and generates a first display light representing the virtual image and a second display light representing the real image; a polarization control element that switches the polarization state of the first display light and the second display light; and an image of the virtual image formed by emitting the first display light in the first polarization state from the emission port through a first optical path, and emitting the second display light in the second polarization state from the emission port through a second optical path. The head-up display device comprises an imaging optical system that forms a real image by illuminating the display, a control unit that controls the generation of the display light by the display, the polarization state of the display light by the polarization control element, and the lighting and extinguishing of the light source, wherein when the control unit receives a display image switching signal, it turns off the light source, switches between the first display light in the first polarization state and the second display light in the second polarization state, turns on the light source, and controls the emission of the virtual image shown by the first display light or the real image shown by the second display light from the output port to form an image on the light-emitting member.

[0009] In the first embodiment, in a head-up display device in which the display and light source are shared for virtual image display and real image display, when the control unit receives a display image switching signal, it turns off the light source and switches between a first display light in a first polarization state and a second display light in a second polarization state, turns on the light source and controls the emission of the virtual image shown by the first display light or the real image shown by the second display light from the emitter and forms an image on the light-emitting member. In this way, when the control unit receives a display image switching signal, it turns off the light source, switches between the virtual image and the real image generated by the display and switches the polarization state by the polarization control element, and then turns on the light source. This makes it difficult to notice the change in brightness that occurs when switching from virtual image display to real image display, or from real image display to virtual image display. Therefore, when switching the display image, it is possible to reduce the discomfort caused to the occupant, who is the viewer, by the difference in brightness between the virtual image display and the real image display.

[0010] Here, the "display image switching signal" is a signal transmitted from an operating device 20, such as a switch that switches the vehicle's driving mode (manual driving, automatic driving), operated by the occupant who is the viewer, as shown in Figure 3. The control unit controls the display 12 and the imaging optical system 13 so that, for example, as shown in Figure 1, a first display light L1 representing vehicle information, route guidance information, warning displays, etc. is generated and the first display light L1, which is first polarization (S polarization), is emitted, when driving manually. For example, as shown in Figure 2, the control unit controls the display 12 and the imaging optical system 13 so that a second display light L2 representing an assistant, agent, or character representing them, which supports the driving of the occupant DR who is the viewer, is generated and the second display light L2, which is second polarization (P polarization), is emitted. First polarization (S polarization) refers to polarization where the direction of vibration is perpendicular to the plane of incidence, and second polarization (P polarization) refers to polarization where the direction of vibration is parallel to the plane of incidence.

[0011] A second embodiment is a head-up display device having an emission port, which emits display light from the emission port toward a light-emitting member to allow the viewer to perceive a virtual image and a real image of a display image represented by the display light, comprising: a display that transmits illumination light irradiated by a light source and generates a first display light representing the virtual image and a second display light representing the real image; a polarization control element that switches the polarization state of the first display light and the second display light; and an image of the virtual image formed by emitting the first display light in the first polarization state from the emission port through a first optical path, and an image of the real image formed by emitting the second display light in the second polarization state from the emission port through a second optical path. The head-up display device comprises an imaging optical system, a control unit that controls the generation of the display light by the display unit, the polarization state of the display light by the polarization control element, and the brightness of the light source, wherein when the control unit receives a switching signal for the display image, it lights up the light source at a first brightness, switches between the first display light in the first polarization state and the second display light in the second polarization state, and controls the light source to emit the virtual image shown by the first display light or the real image shown by the second display light from the output port and image it onto the light-emitting member at a second brightness higher than the first brightness that can display the display image.

[0012] In the second embodiment, in a head-up display device in which the display and light source are shared for virtual image display and real image display, when the control unit receives a display image switching signal, it lights up the light source at a first brightness (low brightness) to switch between a first display light in a first polarization state and a second display light in a second polarization state, changes the light source to a second brightness higher than the first brightness (normal brightness required for virtual / real image display), and controls the emission of the virtual image shown by the first display light or the real image shown by the second display light from the emitter to form an image on the light-emitting member. In this way, when the control unit receives a signal to switch the display image, it turns off the light source, switches between the virtual image and the real image generated by the display, switches the deflection state by the deflection control element, and then turns on the light source. This makes it difficult to notice the change in brightness that occurs when switching from a virtual image display to a real image display, or from a real image display to a virtual image display. Therefore, when switching the display image without turning off the light source, it is possible to reduce the discomfort caused to the viewer by the difference in brightness between the virtual image display and the real image display.

[0013] In a third embodiment dependent on the first or second embodiment, the control unit may switch between the first display light representing the virtual image in the first polarization state and the second display light representing the real image in the second polarization state, based on the display image switching signal, without changing the position of the eye box.

[0014] In the third embodiment, the control unit switches between a first display light representing a virtual image in a first polarization state and a second display light representing a real image in a second polarization state without changing the position of the eye box, thereby reducing the discomfort experienced by the viewer when switching between display images. In other words, if the position of the eye box is not changed, when switching from a real image to a virtual image, or from a virtual image to a real image, the displayed image can be immediately confirmed without moving the position of the eye box. This makes it easier to compare the virtual image and the real image compared to when the eye box is changed, and the difference in brightness becomes easier to understand. Therefore, a reduction in discomfort experienced by the viewer when switching between display images can be expected.

[0015] Here, "eyebox" refers to a predetermined rectangular area of ​​a specified size that is the same as, or includes a large portion of (e.g., 80%) of, the area where the viewpoint position (eye position in the height direction) of the occupant, who is the viewer, is assumed to be located within the vehicle interior (also called the eye lipse). The eyebox is determined, for example, by the direction of the display light L1 and L2 emitted from the head-up display device (HUD device 1) (the position where the light is projected onto the light-emitting member WS), as shown in Figures 1 and 2, and can be replaced by the angle and / or position of the relay optical system (e.g., concave mirror 13 (133), etc.) that determines the direction of the display light L1 and L2 emitted from the HUD device 1.

[0016] A fourth aspect includes a display that transmits illumination light irradiated by a light source and generates a first display light representing a virtual image and a second display light representing a real image; a polarization control element that switches the polarization state of the first display light and the second display light; an imaging optical system that forms the virtual image by emitting the first display light in the first polarization state from the exit port through a first optical path, and forms the real image by emitting the second display light in the second polarization state from the exit port through a second optical path; and the generation of the display light by the display, the polarization state of the display light by the polarization control element, and A control method for a head-up display device comprising a control unit that controls the lighting and extinguishing of the light source, the control unit, upon receiving a signal to switch the display image, turns off the light source and then switches between the first display light in the first polarization state and the second display light in the second polarization state; and the control unit turns on the light source and controls the emission of the virtual image shown by the first display light or the real image shown by the second display light from the emission port to form an image on the light-emitting member.

[0017] In the fourth embodiment, in a head-up display device in which the display and light source are shared for virtual image display and real image display, when the control unit receives a display image switching signal, it turns off the light source and switches between a first display light in a first polarization state and a second display light in a second polarization state, turns on the light source and controls the emission of the virtual image shown by the first display light or the real image shown by the second display light from the emitter to form an image on the light-emitting member. In this way, when the control unit receives a display image switching signal, it turns off the light source, switches between the virtual image and the real image generated by the display and switches the polarization state by the polarization control element, and then turns on the light source. This makes it difficult to notice the change in brightness that occurs when switching from virtual image display to real image display, or from real image display to virtual image display. Therefore, when switching the display image, it is possible to reduce the discomfort caused to the viewer by the difference in brightness between the virtual image display and the real image display.

[0018] A fifth aspect includes a display that transmits illumination light irradiated by a light source and generates a first display light representing the virtual image and a second display light representing the real image; a polarization control element that switches the polarization state of the first display light and the second display light; an imaging optical system that forms the virtual image by emitting the first display light in the first polarization state from the exit port through a first optical path, and forms the real image by emitting the second display light in the second polarization state from the exit port through a second optical path; and a control that controls the generation of the display light by the display, the polarization state of the display light by the polarization control element, and the brightness of the light source. A method for controlling a head-up display device comprising a control unit, the method comprising: a step in which the control unit, upon receiving a signal to switch a display image, lights up the light source at a first brightness and switches between the first display light in a first polarization state and the second display light in a second polarization state; and a step in which the control unit controls the light source to emit the virtual image shown by the first display light or the real image shown by the second display light from the emitter and form an image on the light-emitting member, at a second brightness higher than the first brightness at which the display image can be displayed.

[0019] In the fifth embodiment, in a head-up display device in which the display and light source are shared for virtual image display and real image display, when the control unit receives a display image switching signal, it lights up the light source at a first brightness (low brightness) to switch between a first display light in a first polarization state and a second display light in a second polarization state, changes the light source to a second brightness higher than the first brightness (brightness required for virtual / real image display), and controls the emission of the virtual image shown by the first display light or the real image shown by the second display light from the emitter to form an image on the light-emitting member. In this way, when the control unit receives a signal to switch the display image, it turns off the light source, switches between the virtual image and the real image generated by the display, switches the deflection state by the deflection control element, and then turns on the light source. This makes it difficult to notice the change in brightness that occurs when switching from a virtual image display to a real image display, or from a real image display to a virtual image display. Therefore, when switching the display image without turning off the light source, it is possible to reduce the discomfort caused to the viewer by the difference in brightness between the virtual image display and the real image display.

[0020] A sixth aspect is an in-vehicle system comprising: an operating device for setting the driving mode of a vehicle; a monitoring device for monitoring the forward view of the vehicle and the behavior of the vehicle; and a head-up display device having an outlet and emitting display light from the outlet toward a light-emitting member to allow the viewer to see a virtual image and a real image of the display image represented by the display light, wherein the head-up display device includes a display that transmits illumination light irradiated by a light source based on information acquired from the monitoring device and generates a first display light representing the virtual image and a second display light representing the real image; a polarization control element for switching the polarization state of the first display light and the second display light; and an image of the virtual image formed by emitting the first display light in the first polarization state from the outlet in a first optical path, and a second The in-vehicle system comprises an imaging optical system that forms a real image by emitting the second display light in a polarized state from the exit port via a second optical path; and a control unit that controls the generation of the display light by the display, the polarization state of the display light by the polarization control element, and the lighting or brightness of the light source, wherein when the control unit receives a display image switching signal via the operating device, it turns off the light source or lights it up at a first brightness, then switches between the first display light in a first polarized state and the second display light in a second polarized state, lights up the light source, or emits the virtual image shown by the first display light or the real image shown by the second display light from the exit port at a second brightness higher than the first brightness to form an image on the light projector.

[0021] In the sixth aspect, when the control unit of the head-up display device receives a switching signal of the display image set via the operating device, it turns off the light source or lights it at the first luminance, and then switches between the first display light in the first polarization state and the second display light in the second polarization state. Then, with the light source lit or at a second luminance higher than the first luminance, control is performed to project the virtual image indicated by the first display light or the real image indicated by the second display light from the light exit port and form an image on the projection member. Thus, when the control unit of the head-up display device receives a switching signal of the display image generated by an occupant who is the viewer operating the operating device, it turns off the light source (or lights it at the first luminance), switches between the virtual image and the real image generated by the display, and switches the deflection state by the deflection control element, and then lights the light source (or lights it at a second luminance higher than the first luminance). By performing such control, it becomes difficult for the viewer to notice the change in brightness that occurs when switching from virtual image display to real image display or when switching from real image display to virtual image display. Therefore, when switching the display image without turning off the light source, it is possible to reduce the discomfort given to the viewer due to the difference in brightness between the virtual image display case and the real image display case.

[0022] Those skilled in the art will readily understand that the exemplified embodiments according to the present invention can be further modified without departing from the spirit of the present invention.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a diagram showing an example of a configuration including an imaging optical system during virtual image display of a head-up display device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of a configuration including an imaging optical system during real image display of a head-up display device according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing an example of a configuration of an in-vehicle system including a control system of a head-up display device according to an embodiment of the present invention. [Figure 4] FIG. 4 is an operation sequence diagram of a head-up display device according to an embodiment of the present invention. [Figure 5] Figure 5 is a flowchart showing an example of the processing operation of the control unit of the head-up display device according to an embodiment of the present invention, specifically Example 1. [Figure 6] Figure 6 is a flowchart showing an example of the processing operation of the control unit of the head-up display device according to an embodiment of the present invention, specifically Example 2. [Modes for carrying out the invention]

[0024] The best embodiments described below are used to facilitate understanding of the present invention. Therefore, those skilled in the art should note that the present invention is not unduly limited by the embodiments described below.

[0025] (Configuration of the embodiment) The head-up display device of this embodiment will be described below with reference to the drawings. Figure 1 shows the configuration when generating a virtual image VI in the head-up display device of this embodiment (hereinafter simply referred to as HUD device 1 unless otherwise specified), and Figure 2 shows the configuration when generating a real image RI in the HUD device 1 of this embodiment.

[0026] In Figures 1 and 2, the HUD device 1 consists of, for example, a light-emitting diode (light source 14) that emits visible wavelength light mounted on a light source circuit board (not shown), a backlight 11 on which the light source 14 that emits white light is mounted, a display unit 12 that generates an image with the light incident from the backlight 11 (light source 14) and displays the image by switching the polarization of the emitted light between two different polarizations, a first polarization (first polarization state) and a second polarization (second polarization state), and a display light L (in the case of Figure 1) that represents the display image displayed on the display unit 12. The system includes an imaging optical system 13 having multiple mirrors (reflective members) that reflect a first display light L1 representing the virtual image VI (or, in the case of Figure 2, a second display light L2 representing the real image RI) toward a light-emitting member called a windshield WS, and a control unit 15 that controls the display image (virtual image VI / real image RI) on the display unit 12, as well as controlling the switching between the first and second polarizations and turning on and off multiple light sources 14 of the backlight 11, or controlling the brightness of the light sources 14. These components are housed in a housing 16. The housing 16 is provided with an outlet 17 (aperture) from which the display light L(L1,L2) is emitted, and a cover glass 18 is placed in the outlet 17 to protect the interior.

[0027] The imaging optical system 13 forms a virtual image VI (see Figure 1) by emitting a first indicator light L1 in a first polarization state (first polarization) from the exit port 17 through a first optical path OP1 having a first optical path length, and forms a real image RI (see Figure 2) by emitting a second indicator light L2 in a second polarization state (second polarization) from the exit port 17 through a second optical path OP2 having a second optical path length longer than the first optical path length. For this purpose, the imaging optical system 13 includes a first mirror 131 (concave mirror) having a concave shape, a second mirror 132, and a third mirror 133. The first mirror 131 reflects the first indicator light L1 which is first polarization and transmits the second indicator light L2 which is second polarization. The second mirror 132 is a mirror that reflects the second indicator light L2 which is transmitted through the first mirror 131. The respective display lights L (first display light L1, second display light 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 projected onto the windshield WS, allowing the occupant DR of the vehicle C, who is the viewer, to see the respective display images.

[0028] Therefore, the first optical path OP1 passes through the backlight 11 (light source 14), display unit 12, first mirror 131, third mirror 133, emitter 17, and windshield WS, while the second optical path OP2 passes through the backlight 11 (light source 14), display unit 12, first mirror 131, second mirror 132, third mirror 133, emitter 17, and windshield WS to be visible to the crew DR. Thus, the optical path length of the second optical path OP2 is longer because it passes through the second mirror 132. Note that in Figures 1 and 2, although the display unit 12 actually emits countless rays, for the sake of simplicity, the light emitted from the center of the display unit 12 and passing through the center of the eye box is referred to as the representative ray and is indicated by the symbol L. Furthermore, in Figures 1 and 2, the representative light ray emitted from the center of the display unit 12 is shown as a solid line, the light ray emitted from the upper end of the display unit 12 is shown as a dashed-dotted line, and the light ray emitted from the lower end of the display unit 12 is shown as a double-dotted-dotted line.

[0029] The HUD device 1 of this embodiment is positioned below the windshield WS (light-emitting member) of the vehicle C (for example, inside the instrument panel), and emits display light L (first display light L1, second display light L2) and projects it onto the windshield WS (light-emitting member). The display light L(L1, L2) is generated by the backlight 11 (light source 14) and display unit 12 inside the HUD device 1 of this embodiment. The display light L(L1, L2) emitted from the display unit 12 travels through the imaging optical system 13 and is emitted from the outlet 17 of the housing 16 through the cover glass 18. The occupant DR of the vehicle C, who is the viewer, can see the display light L(L1, L2) reflected off the windshield WS (light-emitting member), and by doing so, can see a virtual image VI as shown in Figure 1 on the far side of the windshield WS (light-emitting member) and a real image RI as shown in Figure 2 on the near side.

[0030] The virtual image VI shown in Figure 1 displays information that is highly necessary to draw the attention of the occupant DR, the viewer, on the other side of the windshield WS (light-projecting element) from the occupant DR's perspective. This includes vehicle information such as the vehicle's speed and engine RPM, route guidance displays such as turn-by-turn directions and maps, blind spot indicators, and warning displays such as speed limit exceeding warnings. The real image RI shown in Figure 2 displays information such as entertainment content, assistants or agents supporting the occupant DR, and characters representing them, on the front side of the windshield WS from the occupant DR's perspective. These displays provide a driving environment that reduces the need for eye movement and adjustment of eye focal length. The virtual image VI and real image RI include not only the text and icons representing this information, but also a background, which in a planar view from the occupant DR's perspective appears, for example, as roughly rectangular.

[0031] The display unit 12 includes, for example, a TFT (Thin Film Transistor) type display element 121 (see Figure 3), and a polarization control element 122 provided on the side of the output port 17 along the optical path from the display element 121, which switches the polarization of the emitted display light L between two different polarizations, a first polarization and a second polarization. For example, the first polarization may be S polarization and the second polarization may be P polarization, or vice versa. Furthermore, it is not limited to S polarization and P polarization; it is sufficient that the polarization angles of the first polarization and the second polarization are different, and it is desirable that the polarization angles differ by at least 22.5 degrees or more.

[0032] Furthermore, as shown in Figures 1 and 2, it is desirable that the display unit 12 be positioned at an angle with respect to the optical axis direction of the display light L(L1,L2) in order to take measures to exclude stray light (light leaking from the light source 14 of the backlight 11) and ambient light (light coming in from outside) from the optical path (OP1,OP2) of the display light L(L1,L2).

[0033] The display element 121 is connected to the display control unit 151, as shown in Figure 3 (described later), and forms light representing a figure of any shape according to the signal sent from the display control unit 151. The polarization control element 122 extracts only the light rays with specific polarizations, specifically the first and second polarizations mentioned above, from the light rays emitted from the display element 121, and controls the switching between them. The polarization control element 122 is connected to the display drive unit 152, as shown in Figure 3 (described later), and switches the polarization according to the signal sent from the display drive unit 152.

[0034] The polarization switching by the polarization control element 122 may be performed by electrical processing, or the polarization may be switched by physically rotating a polarizer or waveplate at a predetermined angle with respect to the central axis, with the optical axis direction as the central axis direction, by placing the polarizer or waveplate on the exit side 17 of the polarization control element 122, with respect to the central axis direction. In either case, the polarization switching is performed by the control of the display drive unit 152.

[0035] Here, for example, the first polarization is S-polarized (S-polarized relative to the first mirror 131), and the second polarization is P-polarized (P-polarized relative to the first mirror 131). The first mirror 131 is a mirror that reflects S-polarized light rays and transmits P-polarized light rays relative to the first mirror 131, and the second mirror 132 is a mirror that reflects P-polarized light rays and transmits S-polarized light rays relative to the first mirror 131. In such a configuration, the first display light L1, which is S-polarized, is reflected by the first mirror 131 and guided to the third mirror 133. The second display light L2, which is P-polarized, is transmitted through the first mirror 131, reflected by the second mirror 132, and guided to the third mirror 133. By setting the polarization of the display light L (first display light L1, second display light L2) in such a configuration of the imaging optical system 13, it becomes possible to generate different display images with each of the display lights L1 and L2. First polarization (S polarization) refers to polarization where the direction of vibration is perpendicular to the plane of incidence, while second polarization (P polarization) refers to polarization where the direction of vibration is parallel to the plane of incidence.

[0036] In Figure 2, the optical focus F is positioned closer to the exit port 17 than the first mirror 131, which makes it possible to display the real image RI at any appropriate position in front of the occupant DR. In other words, if the optical focus F is positioned closer to the display 12 than the first mirror 131, the optical focus F will be further away from the second mirror 132, and as the distance increases, the real image RI will be displayed closer to the occupant DR and at a larger size, making it difficult for the occupant DR to see the real image RI. Therefore, it is preferable for the optical focus F to be closer to the second mirror 132, and for this reason, in the HUD device 1 of this embodiment, the imaging optical system 13 is arranged so that the optical focus F is positioned at least between the first mirror 131 and the second mirror 132.

[0037] The control unit 15 controls the polarization state of the display light L by the polarization control element 122, and the on / off status of the backlight 11 (light source 14). The control unit 15 controls the generation of display light L (L1, L2) by the display unit 12, the polarization state of the display light L (L1, L2) by the polarization control element 122, and the on / off status or brightness of the backlight 11 (light source 14). When the control unit 15 receives a "display image switching signal," it can turn off the backlight 11 (light source 14) or turn it on at low brightness Br1, then switch between the first display light L1 in the first polarization state (S polarization) and the second display light L2 in the second polarization state (P polarization), turn on the backlight 11 (light source 14) or turn it on at normal brightness Br2 (provided BR1≦Br2), and emit the virtual image VI shown by the first display light L1 or the real image RI shown by the second display light L2 from the output port 17 to form an image on the windshield WS (light projection member). The configuration and processing details of the control unit 15 will be described later with reference to Figures 3, 5, and 6.

[0038] Here, the "display image switching signal" is a signal generated by the operating device 20 (see Figure 3) when the occupant DR, who is the viewer, operates the operating device 20, for example, to switch the driving mode of the vehicle C (manual driving, automatic driving). The control unit 15 controls the display 12 and the imaging optical system 13 so that, for example, during manual driving, it generates a first display light L1 that represents vehicle information, route guidance information, warning displays, etc., and emits the first display light L1 which is first polarization (S polarization). During automatic driving, it controls the display 12 and the imaging optical system 13 so that it generates a second display light L2 that represents an assistant, agent, or character representing them, etc., to support the driving of the occupant DR, who is the viewer, and emits the second display light L2 which is second polarization.

[0039] Furthermore, the control unit 15 can switch between a first display light L1 representing a virtual image VI in a first polarization state (S polarization) and a second display light L2 representing a real image RI in a second polarization state (P polarization) based on a display image switching signal, without changing the "eyebox". Here, the "eyebox" refers to a pre-set, for example, rectangular area of ​​a predetermined size, which is the same as, or includes most of (e.g., 80%), the area (also called the eye lipse) where the viewpoint position (position of the eyes in the height direction) of the occupant DR, who is the viewer in the vehicle interior, is assumed. The eyebox is determined by the direction of the display lights L1 and L2 emitted from the HUD device 1 of this embodiment (the position where they are projected onto the windshield WS), as shown in Figures 1 and 2, for example, and can be replaced by the angle and / or position of the relay optical system (for example, a concave mirror (first mirror 131), etc.) that determines the direction of the display lights L1 and L2 emitted from the HUD device 1.

[0040] Figure 3 shows an example of the configuration of the in-vehicle system 100, including the control system, in the HUD device 1 of this embodiment. Note that Figure 3 shows only the minimum necessary configuration directly related to the present invention, and other well-known configurations have been omitted.

[0041] In Figure 3, the in-vehicle system 100 of this embodiment includes at least an operating device 20 for setting the driving mode of the vehicle C, a monitoring device 30 for monitoring the forward view of the vehicle C and the behavior of the vehicle C, and a HUD device 1 (see reference 1) which has an outlet 17 (see reference 1) and emits display light L(L1,L2) from the outlet 17 toward a light-emitting member (windshield WS) to allow the virtual image VI and real image RI of the display image represented by the display light L(L1,L2) to be viewed (here, only the PGU 10 of the HUD1 device shown in Figures 1 and 2 is shown). Note that the in-vehicle system 100 of this embodiment may further include a navigation device, which is not shown.

[0042] The PGU10 comprises a control unit 15, a backlight 11 (light source 14), and a display unit 12, as shown in Figures 1 and 2. The control unit 15 includes a display control unit 151 that commands the display unit 12 to generate light representing an arbitrary shape based on information sent from, for example, a navigation device (not shown), or a monitoring device 30 such as a vehicle speed sensor, RADAR (Radio Detecting and Ranging), or LiDAR (Laser Imaging Detection and Ranging). The control unit 152 controls the switching of the polarization direction of the display unit 12, which generates an image with light emitted from the backlight 11 (light source 14) based on a signal transmitted from, for example, an operating device 20 such as a switch for switching the driving mode of vehicle C (manual driving, automatic driving), and switches the polarization of the emitted light between a first polarization state and a second polarization state that are different from each other, thereby generating display light L (first display light L1, second display light L2) that represents the displayed image.

[0043] Furthermore, the control unit 15 includes a light source drive unit 153 that controls the power supply necessary for turning on and off the light sources 14 mounted on the light source circuit board of the backlight 11. The light source drive unit 153 controls the O / OFF timing and brightness (the value of the current flowing through each LED (current value)) of each LED mounted on the light source circuit board as the light source 14, and also controls the supply voltage to the light source 14, thereby improving power efficiency.

[0044] The display unit 12 includes a TFT-type display element 121 that forms display light L (first display light L1, second display light L2) representing an arbitrary shape based on a signal transmitted from the display control unit 151, and a polarization control element 122 that switches the display light L emitted according to a signal transmitted from the display drive unit 152 to either the first display light L1 with first polarization or the second display light L2 with second polarization. In the configuration example shown in Figure 3, for example, during manual operation, the display drive unit 152 controls the polarization control element 122 so that the first display light L1, which is the first polarization (S polarization), is emitted. At this time, the display control unit 151 controls the polarization control element 122 so that the first display light L1, which represents vehicle information, route guidance information, warning displays, etc. Also, for example, during automatic operation, the display drive unit 152 controls the polarization control element 122 to emit the second display light L2, which is the second polarization (P polarization). At this time, the display control unit 151 controls the display element 121 to generate a second display light L2 that represents an assistant or agent, or a character representing them, to support the driving of the occupant DR, who is the viewer.

[0045] Thus, in the HUD device 1 of this embodiment, when it is desired to display a virtual image VI, the polarization state of the backlight 11 (light source 14) is set in the polarization state reflected by the first mirror 131 of the imaging optical system 13 (first polarization) using the display unit 12 that controls the polarization. As a result, the first display light L1 is reflected by the third mirror 133, incident on the windshield WS (light-emitting member), and reflected by the windshield WS (light-emitting member) to form a virtual image VI that can be displayed on the outside of the vehicle (a virtual imaging area set in front of the vehicle C and inclined with respect to the road surface) on either side of the windshield WS (light-emitting member) (see optical path OP1 in Figure 1). On the other hand, if a real image RI is to be displayed, the polarization state of the backlight 11 (light source 14) is set in the polarization state transmitted by the first mirror 131 of the imaging optical system 13 (second polarization) using the display unit 12 that controls the polarization. As a result, the second display light L2 is reflected by the second mirror 132 and incident on the third mirror 133, reflected again by the third mirror 133 and incident on the windshield WS (light projection member), and reflected by the windshield WS (light projection member) to become a real image RI that can be displayed on the passenger compartment side in front of the occupant DR (an imaging region virtually set when standing perpendicular to the road surface) across the windshield WS (light projection member) (see the second optical path OP2 in Figure 1).

[0046] In other words, for example, the imaging region of a virtual image VI, where the angle with respect to the road surface is less than 45 degrees, appears as if the displayed content is unfolded on the road surface. Therefore, when performing navigation, the displayed content appears as if it is superimposed on the road surface, which has the advantage of enabling intuitive information presentation. On the other hand, the imaging region of a real image RI, where the angle with respect to the road surface is 45 degrees or more, is intended for use in scenarios such as autonomous driving or viewing entertainment content while stopped. It has the advantage of improved visibility because it is displayed while standing relative to the road surface.

[0047] The control unit 15 further controls the brightness by having the light source drive unit 153 vary the ON / OFF timing and the value of the current flowing through each LED, which is mounted on the light source circuit board as the backlight 11 (light source 14), and also controls the supply voltage to the light source 14, thereby improving power efficiency.

[0048] (Operation of the embodiment) Figure 4 is an operation sequence diagram of the HUD device 1 of this embodiment, showing the flow of operation between the backlight 11 (light source 14), the display unit 12 (display element 121), and the polarization control element 122. The operation sequence of the HUD device 1 of this embodiment shown in Figures 1 to 3 will be described below with reference to the sequence diagram in Figure 4.

[0049] In Figure 4, when vehicle C is, for example, in automatic driving mode, the control unit 15 (display drive unit 152) sets the polarization control element 122 to the second polarization state (P polarization) (sequence S01), and controls the display unit 12 (display element 121) to generate a second display light L2 (real image RI) that represents an assistant or agent, or a character representing them, to support the driving of the occupant DR who is the viewer (sequence S02: display of image for real image RI). However, at this timing, the backlight 11 (light source 14) is off, so the real image RI is not displayed (a. display OFF), and when the backlight 11 (light source 14) is turned on (sequence S03), the real image RI indicated by the second display light L2 is emitted from the emitter 17 and an image is formed on the light projector (windshield WS) (b. real image display).

[0050] Next, for example, when the driver DR operates the control device 20, the driving mode changes from automatic driving mode to manual driving mode, and the control unit 15 receives a signal to switch the display image, it controls the backlight 11 (light source 14) to turn off (OFF) (sequence S04). Then, while the backlight 11 (light source 14) is off, the control unit 15 switches the polarization state of the polarization control element 122 from the second polarization state, P polarization, to the first polarization state, S polarization, so that the first display light L1, which is the first polarization (S polarization), is emitted (sequence S06). Then, the display unit 12 (display element 121) is controlled to generate the first display light L1 (virtual image VI) which represents, for example, vehicle information, route guidance information, warning display, etc. (sequence 07: display of image for virtual image VI). However, at this timing, the backlight 11 (light source 14) is off, so the virtual image VI is not displayed (c. display OFF). When the backlight 11 (light source 14) is turned on (sequence 08), the virtual image VI indicated by the first display light L1 is emitted from the emitter 17, and a display image can be formed on the light-emitting member (windshield WS) (d. virtual image display).

[0051] Although the sequence diagram in Figure 4 only illustrates the case of switching from a real image display to a virtual image display, the same sequence is used to control the switching from a virtual image display to a real image display. In this way, by controlling the system so that the backlight 11 (light source 14) is turned on after polarization control and image display switching are performed when the backlight 11 (light source 14) is off, the change in brightness that occurs when switching from a virtual image display to a real image display, or vice versa, becomes less noticeable. Therefore, when switching the displayed image, the discomfort caused to the occupant DR, who is the viewer, by the difference in brightness between the virtual image display and the real image display can be reduced. The same effect can also be obtained by turning on the backlight 11 (light source 14) at low brightness when switching between a real image display and a virtual image display, then performing polarization control and image display switching, and finally turning on the backlight 11 (light source 14) at the brightness required to display the image.

[0052] Next, we will describe in detail below, with reference to Figures 5 and 6, the processing operation of the control unit 15 in each of the following cases: Example 1 is the case in which the deflection state is switched by the deflection control element 122 and the display image (real image / virtual image) is switched by the display element 121 after the backlight 11 (light source 14) is turned off; and Example 2 is the case in which the deflection state is switched by the deflection control element 122 and the display image (real image / virtual image) is switched by the display element 121 after the backlight 11 (light source 14) is turned on at low brightness;

[0053] (Example 1) Refer to Figure 5. Figure 5 is a flowchart showing the processing operation of Embodiment 1. In Figure 5, the control unit 15 of the PGU 10 first determines whether or not a display image switching signal has been received (step ST101). The display image switching signal is a signal transmitted from an operating device 20 that switches the driving mode (manual driving, automatic driving) of the vehicle C, which is operated by the occupant DR. When the control unit 15 receives a display image switching signal that is generated when switching from automatic driving mode to manual driving mode (step ST101 "YES"), the control unit 155 controls the light source drive unit 153 to turn off the backlight 11 (light source 14) (step ST102: backlight (light source) OFF control).

[0054] After the backlight 11 (light source 14) is turned OFF, the control unit 15 confirms that a certain period of time has elapsed (step ST103 "YES"), and then the display drive unit 152 controls the polarization control element 122 to perform polarization state switching control (step ST104). Additionally, the display control unit 151 controls the display element 121 to perform display image switching control (step ST105: display image switching control). In step ST104, the display drive unit 152 controls the imaging optical system 13 so that the first display light L1, which is the first polarization, is emitted via the polarization control element 122 of the display unit 12. That is, the display drive unit 152 switches the imaging optical system 13 so that the first display light L1 is projected from the emitter 17 toward the windshield WS (light projector) in the first optical path OP1. Furthermore, in step ST105, the display control unit 151 controls the display element 121 of the display unit 12 to generate a first display light L1 (virtual image VI) that represents vehicle information, route guidance information, warning displays, etc.

[0055] Next, the control unit 15 controls the backlight 11 (light source 14) to turn on via the light source drive unit 153 (step ST106: backlight (light source) control), and the display unit 12 emits (projects) the generated first display light L1 (virtual image VI) towards the windshield WS (light projection member) via the imaging optical system 13 (first optical path OP1) and the emission port 17 (step ST107: display of real image RI or virtual image VI).

[0056] The reason for monitoring the passage of a certain period of time (the time from receiving the display image switching signal until the backlight 11 (light source 14) turns OFF) in step ST103 is to prevent the control unit 15 from performing polarization state switching control before the backlight 11 (light source 14) turns OFF when it receives the display image switching signal. The sequence control is executed in the following order: backlight 11 (light source 14) turns OFF → polarization state switching control (display image switching control) while the backlight 11 (light source 14) is off → backlight 11 (light source 14) turns ON.

[0057] In the above-described embodiment 1, the case where the display is switched from a real image RI to a virtual image VI according to the driving mode of vehicle C was explained. The same applies when switching from a virtual image VI to a real image RI. In this case, the display drive unit 152 controls the imaging optical system 13 so that a second display light L2, which is a second polarization (P polarization), is emitted via the polarization control element 122 of the display unit 12. That is, the display drive unit 152 switches the imaging optical system 13 so that the second display light L2 is projected from the emitter 17 toward the windshield WS (light-emitting member) in the second optical path OP2. In this way, the control unit 15 can display the virtual image VI or the real image RI after the switch, thereby reducing the discomfort caused by the difference in brightness for the occupant DR and allowing them to see (step ST107).

[0058] According to Embodiment 1, when the control unit 15 receives a display image switching signal, it turns off the backlight 11 (light source 14), switches between the virtual image VI and the real image RI generated by the display unit 12 (display element 121), and switches the deflection state by the deflection control element 122, and then turns on the backlight 11 (light source 14). This makes it difficult to notice the change in brightness that occurs when switching from virtual image display to real image display, or from real image display to virtual image display. Therefore, when switching the display image, it is possible to reduce the discomfort caused to the viewer (occupant DR) by the difference in brightness between the virtual image display and the real image display.

[0059] (Example 2) Refer to Figure 6. Figure 6 is a flowchart of the processing operation of Embodiment 2. In Figure 6, the control unit 15 of the PGU 10 first determines whether or not a display image switching signal has been received (step ST201). The display image switching signal is a signal transmitted from an operating device 20 that switches the driving mode (manual driving, automatic driving) of the vehicle C, which is operated by the occupant DR. When the control unit 15 receives a display image switching signal that is generated when switching from automatic driving mode to manual driving mode (step ST201 "YES"), the control unit 155 determines that the light source drive unit 153 has set the backlight 11 (light source 14) to "low brightness (B r1)" controls the lighting up (Step ST202: Backlight (light source) brightness control B r1 ). Set backlight 11 (light source 14) to low brightness (B r1 When lighting up at low brightness (B), the light source drive unit 153 may control the LEDs of the backlight 11, which serve as light sources 14, to light up only a portion of them, rather than lighting up all of them. r1 )" means, to give an example, the brightness as an image of HUD device 1 is 0 [cd / m²] during the daytime. 2 Higher than 5000 [cd / m²] (candela per square meter), and 5000 [cd / m²] 2 It is in the range of less than ], and at night it is 0 [cd / m 2 Higher than 50 [cd / m²] 2 It is within the range of less than ].

[0060] Next, the control unit 15 confirms that a certain period of time has elapsed since the backlight 11 (light source 14) was turned on at low brightness (Br1) (step ST203 "YES"), and then the display drive unit 152 controls the polarization control element 122 to perform switching control of the polarization state (step ST204), and the display control unit 151 controls the display element 121 to perform switching control of the displayed image (step ST205: switching control of the displayed image). In step ST204, the display drive unit 152 controls the imaging optical system 13 so that the first display light L1, which is the first polarization, is emitted via the polarization control element 122 of the display unit 12. That is, the display drive unit 152 switches the imaging optical system 13 so that the first display light L1 is projected from the emitter 17 toward the windshield WS (light-emitting member) in the first optical path OP1. Furthermore, in step ST205, the display control unit 151 controls the display element 121 of the display unit 12 to generate a first display light L1 (virtual image VI) that represents vehicle information, route guidance information, warning displays, etc.

[0061] Next, the control unit 15 controls the brightness of the light source drive unit 153 to light up the backlight 11 (light source 14), for example, by turning on all of the multiple LEDs mounted on the light source circuit board (brightness Br2) (step ST206). The display unit 12 then emits (projects) the generated first display light L1 (virtual image VI) towards the windshield WS (light-emitting member) via the imaging optical system 13 (first optical path OP1) and the emission port 17 (step ST207: display of real image RI or virtual image VI). Here, brightness Br2 is the normal brightness used when displaying a virtual image VI or a real image RI, and low brightness Br1 ≤ normal brightness Br2.

[0062] The reason for monitoring the passage of a certain period of time (the time from receiving the display image switching signal until the backlight 11 (light source 14) turns OFF) in step ST203 is to prevent the control unit 15 from performing polarization state switching control before the backlight 11 (light source 14) turns OFF when it receives the display image switching signal. The sequence control is executed in the following order: backlight 11 (light source 14) turns OFF → polarization state switching control (display image switching control) while the backlight 11 (light source 14) is off → backlight 11 (light source 14) turns ON.

[0063] In the above-described embodiment 2, the case in which the display is switched from a real image RI to a virtual image VI according to the driving mode of vehicle C was explained. The same applies when switching from a virtual image VI to a real image RI. In this case, the display drive unit 152 controls the imaging optical system 13 so that a second display light L2, which is a second polarization, is emitted via the polarization control element 122 of the display unit 12. That is, the display drive unit 152 switches the imaging optical system 13 so that the second display light L2 is projected from the emitter 17 toward the windshield WS (light-emitting member) in the second optical path OP2. In this way, the control unit 15 displays the virtual image VI or real image RI after the switch (step ST207), thereby allowing the occupant DR to see while reducing the discomfort caused by the difference in brightness.

[0064] According to Embodiment 2, when the control unit 15 receives a display image switching signal, it lights up the backlight 11 (light source 14) at low brightness (Br1) and switches between the virtual image VI and the real image RI generated by the display unit 12 (display element 121) and the deflection state by the deflection control element 122. After this, it controls the backlight 11 (light source 14) to light up at normal brightness Br2 (however, Br1 ≤ Br2). This makes it difficult to notice the change in brightness that occurs when switching from virtual image display to real image display, or from real image display to virtual image display. Therefore, when switching the display image, it is possible to reduce the discomfort caused to the viewer (occupant DR) by the difference in brightness between the virtual image display and the real image display.

[0065] (Effects of the embodiment) As described above, the head-up display device of this embodiment, for example as shown in Figures 1 and 2, has an emission port 17 and emits display light L1 and L2 from the emission port 17 toward a light-emitting member (windshield WS), thereby allowing the user to view the virtual image VI and real image RI of the display image represented by the display light L1 and L2. The HUD device 1 includes a display unit 12 (display element 121) that transmits illumination light emitted by a light source 14 (backlight 11) and generates a first display light L1 representing a virtual image VI and a second display light L2 representing a real image RI; a polarization control element 122 that switches the polarization state of the first display light L1 and the second display light L2; an imaging optical system 13 that forms a virtual image VI by emitting the first display light L1 in the first polarization state from the exit port 17 through a first optical path OP1, and forms a real image RI by emitting the second display light L2 in the second polarization state from the exit port 17 through a second optical path OP2; and a control unit 15 that controls the generation of display light L(L1,L2) by the display unit 12 (display element 121), the polarization state of the display light L(L1,L2) by the polarization control element 122, and the turning on and off of the light source 14 (backlight 11). When the control unit 15 receives a signal to switch the display image, it turns off the light source 14 (backlight 11), then switches between the first display light L1 in the first polarization state and the second display light L2 in the second polarization state, turns on the light source 14 (backlight 11), and controls the emission of the virtual image VI shown by the first display light L1 or the real image RI shown by the second display light L2 from the output port 17 to form an image on the light-emitting member (windshield WS).

[0066] According to the head-up display device (HUD device 1) of this embodiment, in the HUD device 1 in which the display unit 12 and the light source (backlight 11) are shared for virtual image display and real image display, when the control unit 15 receives a display image switching signal, it turns off the light source 14 (backlight 11) to switch between the first display light L1 in a first polarization state (S polarization) and the second display light L2 in a second polarization state (P polarization), turns on the light source 14 (backlight 11) and controls the emission of the virtual image VI shown by the first display light L1 or the real image RI shown by the second display light L2 from the emission port 17 to form an image on the light-emitting member (windshield WS). In this way, when the control unit 15 receives a display image switching signal, it turns off the light source 14 (backlight 11), switches between the virtual image VI and the real image RI generated by the display unit 12, and switches the deflection state by the deflection control element 122, and then turns on the light source 14 (backlight 11). This makes it difficult to notice the change in brightness that occurs when switching from virtual image display to real image display, or from real image display to virtual image display. Therefore, when switching the display image, it is possible to reduce the discomfort caused to the viewer (occupant DR) by the difference in brightness between the virtual image display and the real image display.

[0067] The head-up display device of this embodiment, as shown in Figures 1 and 2, for example, has an emission port 17 and emits display light L (first display light L1, second display light L2) from the emission port 17 toward a light-emitting member (windshield WS), thereby allowing the user to view the virtual image VI and real image RI of the display image represented by the display light L (L1, L2). The HUD device 1 includes a display unit 12 that transmits illumination light emitted by a light source 14 (backlight 11) to generate a first display light L1 representing a virtual image VI and a second display light L2 representing a real image RI; a polarization control element 122 (see Figure 3) that switches the polarization state of the first display light L1 and the second display light L2; an imaging optical system 13 that forms a virtual image VI by emitting the first display light L1 in a first polarization state (S polarization) from the exit port 17 through a first optical path OP1, and forms a real image RI by emitting the second display light L2 in a second polarization state (P polarization) from the exit port 17 through a second optical path OP2; and a control unit 15 that controls the generation of display light L(L1,L2) by the display unit 12, the polarization state of the display light L(L1,L2) by the polarization control element 182, and the brightness of the light source 14 (backlight 11). When the control unit 15 receives a signal to switch the display image, it lights up the light source 14 (backlight 11) at a first brightness Br1, switches between the first display light L1 in a first polarization state (S polarization) and the second display light L2 in a second polarization state (P polarization), and controls the light source 14 (backlight 11) to emit from the output port 17 either the virtual image VI shown by the first display light L1 or the real image RI shown by the second display light L2 at a second brightness Br2 that is higher than the first brightness Br1 that can display the display image, so that it can form an image on the light projector (windshield WS).

[0068] According to the head-up display device (HUD device 1) of this embodiment, in the HUD device 1 in which the display unit 12 and the light source 14 (backlight 11) are shared for virtual image display and real image display, when the control unit 15 receives a display image switching signal, it lights up the light source 14 (backlight 11) at a first brightness Br1 (low brightness) and switches between the first display light L1 in a first polarization state (S polarization) and the second display light L2 in a second polarization state (P polarization). It then changes the light source 14 (backlight 11) to a second brightness Br2 (normal brightness required for virtual / real image display) which is higher than the first brightness Br1, and controls the emission of the virtual image VI shown by the first display light L1 or the real image RI shown by the second display light L2 from the emission port 17 to form an image on the light-emitting member (windshield WS). In this way, when the control unit 15 receives a display image switching signal, it lights up the light source 14 (backlight 11) at low brightness Br1 to switch between the virtual image VI and the real image RI generated by the display unit 12, and switches the deflection state by the deflection control element 182. Then, it controls the light source 14 (backlight 11) to light up at the normal brightness Br2 used to display the virtual image VI or the real image RI. As a result, the occupant DR, who is the viewer, will be less likely to notice the change in brightness that occurs when switching from virtual image display to real image display, or from real image display to virtual image display. Therefore, when switching the display image without turning off the light source 14 (backlight 11), the sense of discomfort caused by the difference in brightness between the virtual image display and the real image display can be reduced.

[0069] Furthermore, according to the head-up display device (HUD device 1) of this embodiment, the control unit 15 switches between a first display light L1 representing a virtual image VI in a first polarization state (S polarization) and a second display light L2 representing a real image RI in a second polarization state (P polarization) without changing the position of the eye box. When the position of the eye box is not changed, the displayed image can be immediately confirmed without moving the position of the eye box when switching from a real image display to a virtual image display, or from a virtual image display to a real image display. This makes it easier to compare the virtual image display and the real image display and makes the difference in brightness easier to understand, thus reducing the discomfort felt by the occupant DR, who is the viewer, when switching the displayed image.

[0070] The control method for the head-up display device of this embodiment includes, for example, as shown in Figures 1 and 2, a display unit 12 that transmits illumination light irradiated by a light source 14 (backlight 11) to generate a first display light L1 representing a virtual image VI and a second display light L2 representing a real image RI, a polarization control element 122 (see Figure 3) that switches the polarization state of the first display light L1 and the second display light L2, and the first display light L1 in the first polarization state (S-polarization) that exits from the exit port 17 through the first optical path OP1. This is a control method for a head-up display device (HUD device 1) comprising: an imaging optical system 13 that forms a virtual image VI by causing a second display light L2 in a second polarization state (P polarization) to be emitted from the exit port 17 through a second optical path OP2 to form a real image RI; and a control unit 15 that controls the generation of display light L(L1,L2) by a display unit 12, the polarization state of the display light L(L1,L2) by a polarization control element 122, and the lighting and turning off of a light source 14 (backlight 11). The control method, for example as shown in Figure 5, includes the steps of: when the control unit 15 receives a display image switching signal (ST101 "YES"), it turns off the light source 14 (backlight 11) (ST102), then switches between a first display light L1 in a first polarization state (S polarization) and a second display light L2 in a second polarization state (P polarization) (ST103 to ST105); and the control unit 15 turns on the light source 14 (backlight 11) and controls the emission of the virtual image VI shown by the first display light L1 or the real image RI shown by the second display light L2 from the emission port 17 to form an image on the light projection member (windshield WS) (ST106, ST107).

[0071] According to the control method for the head-up display device of this embodiment, in a head-up display device (HUD1) in which the display unit 12 and the light source 14 (backlight 11) are shared for virtual image display and real image display, when the control unit 15 receives a display image switching signal, it turns off the light source 14 (backlight 11) to switch between the first display light L1 in a first polarization state (S polarization) and the second display light L2 in a second polarization state (P polarization), turns on the light source 14 (backlight 11) to emit the virtual image VI shown by the first display light L1 or the real image RI shown by the second display light L2 from the output port 17 and forms an image on the light-emitting member (windshield WS). In this way, when the control unit 15 receives a display image switching signal, it turns off the light source 14 (backlight 11), switches between the virtual image VI and the real image RI generated by the display unit 12 (display element 121), and switches the deflection state by the deflection control element 122, and then turns on the light source 14 (backlight 11). As a result, the occupant DR, who is the viewer, is less likely to notice the change in brightness that occurs when switching from virtual image display to real image display, or from real image display to virtual image display. Therefore, when switching the display image, the discomfort caused to the occupant DR, who is the viewer, by the difference in brightness between the virtual image display and the real image display can be reduced.

[0072] Furthermore, the control method for the head-up display device of this embodiment includes, for example, as shown in Figures 1 and 2, a display unit 12 that transmits illumination light irradiated by a light source 14 (backlight 11) to generate a first display light L1 representing a virtual image VI and a second display light L2 representing a real image RI, a polarization control element 122 (see Figure 3) that switches the polarization state of the first display light L1 and the second display light L2, and a first optical path OP1 that emits the first display light L1 in the first polarization state (S polarization) from the exit port 17. This is a control method for a head-up display device (HUD device 1) comprising: an imaging optical system 13 that forms a virtual image VI by emitting light from a second optical path OP2 to form a real image RI by emitting a second display light L2 in a second polarization state (P polarization) from an exit port 17; and a control unit 15 that controls the generation of display light L(L1,L2) by a display unit 12, the polarization state of the display light L(L1,L2) by a polarization control element 122, and the brightness of a light source 14 (backlight 11). The control method, for example as shown in Figure 6, includes the steps (ST202-ST205) of the control unit 15, upon receiving a signal to switch the display image (step ST201 "YES"), turning on the light source 14 (backlight 11) at a first brightness Br1 and switching between a first display light L1 in a first polarization state (S polarization) and a second display light L2 in a second polarization state (P polarization); and the control unit 15 controlling the light source 14 (backlight 11) to emit a virtual image VI shown by the first display light L1 or a real image RI shown by the second display light L2 from the output port 17 at a second brightness Br2 higher than the first brightness Br1 that can display the display image, and forming an image on the light projector (windshield WS).

[0073] According to the control method for the head-up display device of this embodiment, in a head-up display device (HUD device 1) in which the display unit 12 and the light source 14 (backlight 11) are shared for virtual image display and real image display, when the control unit 15 receives a display image switching signal, it lights up the light source 14 (backlight 11) at a first brightness (low brightness Br1) and switches between the first display light L1 in a first polarization state (S polarization) and the second display light L2 in a second polarization state (P polarization). It then changes the light source 14 (backlight 11) to a second brightness Br2 (normal brightness required for virtual / real image display) which is higher than the first brightness Br1, and controls the emission of the virtual image VI shown by the first display light L1 or the real image RI shown by the second display light L2 from the emission port 17 to form an image on the light-emitting member (windshield WS). In this way, when the control unit 15 receives a display image switching signal, it controls the light source 14 (backlight 11) to light up at low brightness Br1 to switch between the virtual image VI and the real image RI generated by the display unit 12 (display element 121), and after switching the deflection state by the deflection control element 122, it controls the light source 14 (backlight 11) to light up at normal brightness Br2 (Br1≦Br2). As a result, the occupant DR, who is the viewer, will not easily notice the change in brightness that occurs when switching from virtual image display to real image display, or from real image display to virtual image display. Therefore, when switching the display image without turning off the light source 14 (backlight 11), the discomfort caused to the viewer by the difference in brightness between the virtual image display and the real image display can be reduced.

[0074] The in-vehicle system of this embodiment is, for example, as shown in Figures 1, 2, and 3, an in-vehicle system 100 that includes an operating device 20 for setting the driving mode of the vehicle C, a monitoring device 30 for monitoring the forward view of the vehicle C and the behavior of the vehicle C, and a head-up display device (HUD device 1) having an outlet 17 that emits display light L(L1, L2) from the outlet 17 toward a light-emitting member WS, thereby allowing the virtual image VI and real image RI of the display image represented by the display light L(L1, L2) to be viewed. The HUD device 1 in this in-vehicle system 100 includes a display unit 12 that transmits illumination light emitted by a light source 14 (backlight 11) based on information acquired from a monitoring device 30 to generate a first display light L1 representing a virtual image VI and a second display light L2 representing a real image RI; a polarization control element 122 that switches the polarization state of the first display light L1 and the second display light L2; an imaging optical system 13 that forms a virtual image VI by emitting the first display light L1 in a first polarization state (S polarization) from the exit port 17 through a first optical path OP1, and forms a real image RI by emitting the second display light L2 in a second polarization state (P polarization) from the exit port 17 through a second optical path OP2; and a control unit 15 that controls the generation of display light L(L1,L2) by the display unit 12, the polarization state of the display light L(L1,L2) by the polarization control element 122, and the lighting or brightness of the light source 14 (backlight 11). Then, when the control unit 15 receives a display image switching signal set via the operating device 20, it turns off the light source 14 (backlight 11) or turns it on at a first brightness Br1, then switches between the first display light L1 in a first polarization state (S polarization) and the second display light L2 in a second polarization state (P polarization), turns on the light source 14 (backlight 11), or turns it on at a second brightness Br2 which is higher than the first brightness Br1, and controls the emission of the virtual image VI shown by the first display light L1 or the real image RI shown by the second display light L2 from the emission port 17 to form an image on the light projector (windshield WS).

[0075] According to the in-vehicle system 100 of this embodiment, when the control unit 15 of the HUD device 1 receives a display image switching signal set via the operating device 20, it turns off the light source 14 (backlight 11) or turns it on at a first brightness Br1, then switches between the first display light L1 in a first polarization state (S polarization) and the second display light L2 in a second polarization state (P polarization), turns on the light source 14 (backlight 11), or turns it on at a second brightness Br2 which is higher than the first brightness Br1, and controls the emission of the virtual image VI shown by the first display light L1 or the real image RI shown by the second display light L2 from the emission port 17 to form an image on the light-emitting member (windshield WS). In this way, when the control unit 15 of the HUD device 1 receives a display image switching signal generated by the occupant DR operating the control device 20, it turns off the light source 14 (backlight 11) (or turns it on at a first brightness Br1), switches between the virtual image VI and the real image RI generated by the display unit 12 and switches the deflection state by the deflection control element 122, and then turns on the light source 14 (backlight 11) (or turns it on at a second brightness Br2 which is higher than the first brightness Br1). As a result, it becomes difficult to notice the change in brightness that occurs when switching from virtual image display to real image display, or from real image display to virtual image display. Therefore, when switching the display image without turning off the light source 14 (backlight 11), it is possible to reduce the discomfort caused to the occupant DR, who is the viewer, by the difference in brightness between the virtual image display and the real image display.

[0076] In this embodiment, a windshield WS is used as the light-transmitting member, but flat glass or a combiner may also be used.

[0077] The present invention is not limited to the exemplary embodiments described above, and those skilled in the art will be able to easily modify the exemplary embodiments described above to the extent included in the claims. [Explanation of symbols]

[0078] 1...Head-Up Display Device (HUD), 10...Image Generation Unit (PGU), 10...Image Generation Unit (PGU), 11...Backlight (Light Source), 12...Display Unit, 13...Imaging Optical System, 14...Light Source, 15...Control Unit, 17...Ejector, 20...Operating Device, 30...Monitoring Device, 100...In-Vehicle System, 131... • First mirror (concave mirror), 132... Second mirror, 133... Third mirror, 121... Display element, 122... Polarization control element, 151... Display control unit, 152... Display drive unit, 153... Light source drive unit, RI... Real image, VI... Virtual image, L1... First display light, L2... Second display light, OP1... First optical path, OP2... Second optical path

Claims

1. A head-up display device having an emission port, which emits display light from the emission port toward a light-emitting member, thereby allowing the viewer to perceive both a virtual image and a real image of the display image represented by the display light, A display device that transmits illumination light irradiated by a light source to generate a first display light representing the virtual image and a second display light representing the real image, A polarization control element that switches the polarization state of the first display light and the second display light, An imaging optical system that forms a virtual image by emitting the first indicator light in a first polarization state from the exit port through a first optical path, and forms a real image by emitting the second indicator light in a second polarization state from the exit port through a second optical path, The system comprises a control unit that controls the generation of the display light by the display unit, the polarization state of the display light by the polarization control element, and the on / off switching of the light source, The control unit, A head-up display device that, upon receiving a signal to switch the display image, turns off the light source, switches between the first display light in the first polarization state and the second display light in the second polarization state, turns on the light source, and controls the emission of the virtual image shown by the first display light or the real image shown by the second display light from the emission port to form an image on the light-emitting member.

2. A head-up display device having an emission port, which emits display light from the emission port toward a light-emitting member, thereby allowing the viewer to perceive both a virtual image and a real image of the display image represented by the display light, A display device that transmits illumination light irradiated by a light source to generate a first display light representing the virtual image and a second display light representing the real image, A polarization control element that switches the polarization state of the first display light and the second display light, An imaging optical system that forms a virtual image by emitting the first indicator light in a first polarization state from the exit port through a first optical path, and forms a real image by emitting the second indicator light in a second polarization state from the exit port through a second optical path, The system comprises a control unit that controls the generation of the display light by the display unit, the polarization state of the display light by the polarization control element, and the brightness of the light source, The control unit, A head-up display device that, upon receiving a switching signal for the display image, lights up the light source at a first brightness, switches between the first display light in a first polarization state and the second display light in a second polarization state, and controls the light source to emit the virtual image shown by the first display light or the real image shown by the second display light from the emitter at a second brightness higher than the first brightness that can display the display image, so that it forms an image on the light-emitting member.

3. The control unit, The head-up display device according to claim 1 or 2, wherein the switching between the first display light representing the virtual image in the first polarization state and the second display light representing the real image in the second polarization state is performed without changing the eye box, based on the switching signal of the display image.

4. A control method for a head-up display device comprising: a display unit that transmits illumination light irradiated by a light source and generates a first display light representing a virtual image and a second display light representing a real image; a polarization control element that switches the polarization state of the first display light and the second display light; an imaging optical system that forms the virtual image by emitting the first display light in the first polarization state from the exit port through a first optical path and forms the real image by emitting the second display light in the second polarization state from the exit port through a second optical path; and a control unit that controls the generation of the display light by the display unit, the polarization state of the display light by the polarization control element, and the on / off of the light source, wherein The control unit, Upon receiving a signal to switch the display image, the light source is turned off, and then the first display light in the first polarization state and the second display light in the second polarization state are switched. The control unit, A control method for a head-up display device, comprising the steps of: turning on the light source and controlling the emission of the virtual image shown by the first display light, or the real image shown by the second display light, from the emission port to form an image on a light-emitting member.

5. A control method for a head-up display device comprising: a display that transmits illumination light irradiated by a light source and generates a first display light representing a virtual image and a second display light representing a real image; a polarization control element that switches the polarization state of the first display light and the second display light; an imaging optical system that forms the virtual image by emitting the first display light in the first polarization state from the exit port through a first optical path and forms the real image by emitting the second display light in the second polarization state from the exit port through a second optical path; and a control unit that controls the generation of the display light by the display, the polarization state of the display light by the polarization control element, and the brightness of the light source, wherein The control unit, Upon receiving a signal to switch the display image, the light source is turned on at a first brightness level, and the first display light in the first polarization state and the second display light in the second polarization state are switched. The control unit, A control method for a head-up display device, comprising the step of controlling the light source to emit the virtual image shown by the first display light or the real image shown by the second display light from the output port and form an image on a light-emitting member, with the second brightness being higher than the first brightness that can display the display image.

6. An in-vehicle system comprising: an operating device for setting the vehicle's driving mode; a monitoring device for monitoring the vehicle's forward view and the vehicle's behavior; and a head-up display device having an outlet from which display light is emitted toward a light-emitting member, thereby allowing the viewer to perceive both a virtual image and a real image of the display represented by the display light. The head-up display device is A display device that transmits illumination light emitted by a light source based on information acquired from the monitoring device, and generates a first display light representing the virtual image and a second display light representing the real image, A polarization control element that switches the polarization state of the first display light and the second display light, An imaging optical system that forms a virtual image by emitting the first indicator light in a first polarization state from the exit port through a first optical path, and forms a real image by emitting the second indicator light in a second polarization state from the exit port through a second optical path, The system comprises a control unit that controls the generation of the display light by the display unit, the polarization state of the display light by the polarization control element, and the illumination or brightness of the light source, The control unit, An in-vehicle system that, upon receiving a switching signal for a display image set via the operating device, turns off the light source or turns it on at a first brightness, then switches between the first display light in the first polarization state and the second display light in the second polarization state, turns on the light source or turns it on at a second brightness higher than the first brightness, and controls the emission of the virtual image shown by the first display light or the real image shown by the second display light from the emission port to form an image on the light-emitting member.

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