Head-up display device and method of controlling head-up display device

Abstract

To suppress, when one of a real image and a virtual image is displayed, the waste of light emitted from a pixel in a direction for displaying the other image.SOLUTION: A head-up display device comprises: a backlight 11; a display 12; a polarization control element 122 that switches between polarization states of display light; an imaging optical system 13 that causes first display light L1 of a first polarization state to be emitted from an emission port 17 via a first optical path OP1 having a first optical path length to form a virtual image VI, and causes second display light L2 (see Fig. 2) of a second polarization state to be emitted from the emission port via a second optical path OP2 having a second optical path length longer than the first optical path length to form a real image RI; and a control section 15 that controls the polarization states of the display light by the polarization control element and turning on and off of each of light sources. The control section controls such that an area of the light sources to be turned on more strongly than a predetermined intensity when the real image RI is displayed is larger than an area of the light sources to be turned on more strongly than a predetermined intensity when the virtual image VI is displayed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a head-up display device that emits display light from an emission port toward a light-projecting member, thereby allowing a virtual image and a real image of a display image represented by the display light to be visually recognized. [Background technology]

[0002] For example, Patent Document 1 (paragraph

[0006] ), which was unpublished as of the filing date of this application, describes a head-up display device that includes an imaging optical system that includes a polarized reflecting member (for example, the first mirror 13 (131) in FIG. 7) whose transmittance (reflectance) varies depending on the polarization state, and a second reflecting member (third mirror 13 (133)) that reflects the display light that has passed through the polarized reflecting member, whereby display light L1 in a first polarization state is emitted along a first optical path where it is reflected by the surface of the polarized reflecting member to form a virtual image VI, and display light L2 in a second polarization state is emitted along a second optical path where it is reflected by the second reflecting member to form a real image, and a single-system image generation unit PGU (Picture Generation Unit) that is positioned on the first optical path inside a first focal point F1 of the imaging optical system and on the second optical path outside a second focal point F2 of the imaging optical system, and that switches between the first and second polarization states. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent application 2023-148856 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the technology described in Patent Document 1, for example, of the display light (pixel light) emitted from one pixel of an image generation unit (PGU: Picture Generation Unit), the pixel light emitted in a first direction is formed as a real image, and the pixel light emitted in a second direction is formed as a virtual image. In other words, when one of a real image or a virtual image is displayed, the light emitted from the pixel in the direction for displaying the other is wasted, resulting in a decrease in light utilization efficiency, and there is room for improvement.

[0005] 15(A) and 15(B) show the light irradiation direction (emission direction from one pixel) of the light source 214 when a virtual image is displayed and when a real image is displayed, respectively. In FIGS. 15(A) and 15(B), symbol L1 represents a wide light ray area irradiated from the light source 214 mounted on the light source circuit board 240 to the display 212 when a virtual image is displayed, and symbol L2 represents a wide light ray area irradiated from the light source 214 mounted on the light source circuit board 240 to the display 212 when a real image is displayed, both of which are shown surrounded by a dashed dotted line. In a typical head-up display device, it is sufficient for an image to be visible in the eyebox, so a backlight configuration that is bright in the eyebox and has little waste is achieved by limiting the direction of the backlight light (the direction of light emitted from the pixel). However, when displaying virtual and real images, it is necessary to emit light emitted from one pixel in a wide range (for example, in directions A, B, C, and D).

[0006] When a real image is displayed, the wide range of light emitted from one pixel is classified into light in a range that is visible as a real image in the eye box (for example, in Figure 15(B), light that is irradiated onto the display 212 in the direction indicated by the solid arrow), and light in a range that is not visible as a real image (for example, in Figure 15(B), light C and D that are indicated by dashed lines, where C is wasted light that is irradiated perpendicular to the surface of the display 212 and D is wasted light that is irradiated outward from the display 212). On the other hand, when a virtual image is displayed, the light is classified into light in the range that is perceived as a virtual image in the eye box (for example, light that is irradiated onto the display 212 in the direction indicated by the solid arrow in Figure 15(A)) and light in the range that is not perceived as a virtual image (for example, light A, C, and D indicated by dashed lines, where A is wasted light that is irradiated inward of the display 212, C is wasted light that is irradiated perpendicular to the surface of the display 212, and D is wasted light that is irradiated outward from the display 212), and it has been found that the outer edge side of the light source area (light source circuit board 240) where the light source 214 is implemented is perceived as a real image, and light in the direction A is likely to be perceived as a virtual image.

[0007] The present invention has been made in light of the above circumstances, and aims to provide a head-up display device or the like that prevents light emitted from pixels in a direction for displaying a real image or a virtual image from being wasted when the other image is being displayed, thereby improving light utilization efficiency, by controlling the arrangement in the light source area of ​​light sources that are turned on when a real image or a virtual image is displayed and when the other image is being displayed.

[0008] Other objects of the present invention will become apparent to those skilled in the art by referring to the following exemplary aspects and best modes, as well as the accompanying drawings. [Means for solving the problem]

[0009] In order to facilitate an understanding of the outline of the present invention, the following examples are given of embodiments according to the present invention.

[0010] A first aspect is a head-up display device having an outlet and emitting display light from the outlet toward a light-projecting member, thereby allowing the user to view a virtual image and a real image of a display image represented by the display light. The head-up display device includes: a backlight equipped with a plurality of light sources; a display that generates display light by transmitting illumination light emitted by the light sources; a polarization switching element that switches the polarization state of the display light; an imaging optical system that forms the virtual image by emitting first display light in a first polarization state from the outlet along a first optical path having a first optical path length, and forms the real image by emitting second display light in a second polarization state from the outlet along a second optical path having a second optical path length longer than the first optical path length; and a control unit that controls the polarization state of the display light by the polarization switching element and the turning on and off of each of the light sources, wherein the control unit controls the area of ​​the light sources that are lit at a stronger intensity than a predetermined intensity when displaying the real image to be larger than the area of ​​the light sources that are lit at a stronger intensity than the predetermined intensity when displaying the virtual image.

[0011] Here, the term "predetermined intensity" refers to the default light intensity of light irradiated onto a display from a backlight equipped with multiple light sources when displaying a virtual image or a real image. Here, the intensity of the light intensity is controlled by the area of ​​the light source to be turned on. That is, when displaying a real image, the area of ​​the light source to be turned on stronger than the predetermined intensity is controlled to be larger than the area of ​​the light source to be turned on stronger than the predetermined intensity when displaying a virtual image. Furthermore, the term "area of ​​the light source to be turned on" refers to, for example, the mounting area of ​​the light source 14 to be turned on among the multiple light sources 14 mounted on the light source circuit board 140 of the backlight 11 (area A illuminated when generating a virtual image, area B illuminated when generating a real image), as shown in FIG. 8 . In a first aspect, the control unit controls the area of ​​the light source that is turned on stronger than a predetermined intensity when a real image is displayed to be larger than the area of ​​the light source that is turned on stronger than a predetermined intensity when a virtual image is displayed, thereby turning on, for example, the outer edge side of the light source area when a real image is displayed, and turning off, for example, the outer edge side of the light source area that is not visually recognized as a virtual image when a virtual image is displayed, thereby eliminating the difference in brightness between when a real image is displayed and when a virtual image is displayed, and improving light utilization efficiency. In this way, when one of a real image and a virtual image is displayed, wasting of light emitted from pixels in a direction for displaying the other is suppressed, thereby improving light utilization efficiency.

[0012] In a second aspect dependent on the first aspect, when switching the display from the virtual image to the real image, the control unit may control the light source arranged in an implementation area that does not overlap with the display when viewed from the normal direction of the light source circuit board of the backlight on which the light source is mounted to be lit at a stronger intensity than the predetermined intensity.

[0013] In the second aspect, when the control unit switches the display from a virtual image to a real image, for example, as shown in Fig. 7(B), the control unit controls the light source 14 (light rays indicated by solid arrows in the figure) arranged in a mounting area (outer edge areas Y1 and Y2 of the light source circuit board 140) that does not overlap with the display device 12 when viewed from the normal direction of the light source circuit board 140 of the backlight 11 on which the light source 14 is mounted) to light up at a higher intensity than a predetermined intensity. This prevents the wasting of light emitted from the pixel in the direction to display the other image (virtual image) when one of the real image and the virtual image (real image) is displayed, thereby improving light utilization efficiency. Note that in Figs. 7(A) and 7(B), solid arrows indicate light rays used for display, and dashed arrows indicate light rays not used for display.

[0014] In a third aspect dependent on the first aspect, the control unit may perform control to increase the area of ​​the light source mounted on the light source circuit board of the backlight that is lit with a stronger intensity than a predetermined intensity when the real image is displayed, along the long side direction of the rectangular area of ​​the display, compared to the area of ​​the light source mounted on the light source circuit board that is lit with a stronger intensity than a predetermined intensity when the virtual image is displayed.

[0015] In the third aspect, the control unit controls the area of ​​light sources 14 mounted on light source circuit board 140 of the backlight, which is turned on with more intensity than a predetermined intensity when a real image is displayed (area B lit when a real image is generated), to be larger along the long side direction H of the display than the area of ​​light sources mounted on light source circuit board 140, which is turned on with more intensity than a predetermined intensity when a virtual image is displayed (area A lit when a virtual image is generated). Alternatively, when switching from real image display to virtual image display, the control unit may control the light sources 14 at the edge (one row above and below) of area B lit when a real image is generated to be turned off, for example, as shown in FIG.

[0016] In a fourth aspect dependent on the first aspect, the control unit may perform control so that the area of ​​the light source mounted on the light source circuit board of the backlight that is lit with a stronger intensity than a predetermined intensity when the real image is displayed is larger along each of the long side direction and the short side direction of the rectangular area of ​​the display device than the area of ​​the light source mounted on the light source circuit board that is lit with a stronger intensity than a predetermined intensity when the virtual image is displayed.

[0017] 10(A) and 10(B), the control unit controls the area of ​​the light source 14 mounted on the light source circuit board 140 of the backlight 11, which is turned on with more intensity than a predetermined intensity when a real image is displayed, to be larger along both the long side direction (H) and the short side direction (V) of the display than the area of ​​the light source 14 mounted on the light source circuit board 140, which is turned on with more intensity than a predetermined intensity when a virtual image is displayed, as shown in FIG. 10(A) and 10(B). Therefore, when one of a real image and a virtual image is displayed, the light emitted from the pixel in the direction for displaying the other image is prevented from being wasted, thereby improving light utilization efficiency. In addition to the lighting patterns of the light sources 14 shown in Figures 10(A) and (B), other control may be performed, such as (1) turning off all of the light sources 14 arranged on the outer edge of the light source circuit board 140, (2) turning off the light sources 14 arranged on one edge, (3) turning off the light along one edge of both the long side H and the short side, or (4) turning off some of the light sources 14 when a real image is displayed and turning on some of the light sources 14 that were turned off when the real image was displayed when a virtual image was displayed.

[0018] In a fifth aspect dependent on the first aspect, the control unit may perform control to increase the area of ​​the light source mounted on the light source circuit board of the backlight that is turned on at a higher intensity than a predetermined intensity when the real image is displayed, along each of the long side direction and the short side direction of the rectangular area of ​​the display, compared to the area of ​​the light source mounted on the light source circuit board that is turned on at a higher intensity than a predetermined intensity when the virtual image is displayed, and may also perform control to increase the area of ​​the light source that is increased along the long side direction more than along the short side direction.

[0019] In the fifth aspect, for example, as shown in Figures 10(A) and 10(B), the control unit controls the area of ​​the light source 14 mounted on the light source circuit board 140 of the backlight 11, which is lit at a higher intensity than a predetermined intensity when a real image is displayed (lighting area B when a real image is generated), to be larger along each of the long side direction (H) and short side direction (V) of the display than the area of ​​the light source 14 mounted on the light source circuit board 140, which is lit at a higher intensity than a predetermined intensity when a virtual image is displayed (lighting area A when a virtual image is generated).In this case, by controlling the area of ​​the light source to be larger in the long side direction H than in the short side direction V, when one of a real image or a virtual image is displayed, the wastage of light emitted from the pixel in the direction for displaying the other is suppressed, and light utilization efficiency can be more efficiently improved.

[0020] A sixth aspect is a head-up display device having an outlet, and emitting display light from the outlet toward a light-projecting member to allow a user to view a virtual image and a real image of a display image represented by the display light, the head-up display device including: a first backlight having a plurality of first light sources mounted thereon; a first display that generates first display light by transmitting illumination light from the first light sources; a second backlight having a plurality of second light sources mounted thereon; and a second display that generates second display light by transmitting illumination light from the second light sources; the first display light is emitted from the outlet along a first optical path having a first optical path length to form the virtual image; The display device includes an imaging optical system that forms the real image by emitting light from the outlet along a second optical path having an optical path length, a first control unit that controls the turning on and off of each of the first light sources, and a second control unit that controls the turning on and off of each of the second light sources, wherein the first control unit controls the first light sources to be turned on at a stronger intensity than a predetermined intensity when displaying the virtual image using the first display light, and the second control unit controls the area of ​​the light sources that are turned on at a stronger intensity than the predetermined intensity when displaying the real image using the second display light to be larger than the area of ​​the light sources that are turned on at a stronger intensity than the predetermined intensity when displaying the virtual image.

[0021] In a sixth aspect, a head-up display device includes a backlight, a display, and a control unit, each of which has two systems for generating a virtual image and a real image, and which share an imaging optical system. The first control unit controls the first light source to be illuminated at a higher intensity than a predetermined intensity when a virtual image is displayed using the first display light, and the second control unit controls the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when a real image is displayed using the second display light, so that the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when a virtual image is displayed is larger than the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when a virtual image is displayed. With this configuration, for example, when a real image is displayed, the outer edge of the light source area is illuminated, and when a virtual image is displayed, the outer edge of the light source area that is not visually recognized as a virtual image is turned off. This configuration can improve light utilization efficiency while suppressing waste and eliminating the difference in brightness between when a real image and a virtual image are displayed. In this way, when one of a real image and a virtual image is displayed, the light emitted from the pixel in the direction intended to display the other is suppressed from being wasted, thereby improving light utilization efficiency.

[0022] A seventh aspect includes a backlight having a light source mounting substrate on which a plurality of light sources are mounted, a display that generates display light by transmitting illumination light from the light sources of the backlight, a polarization switching element that switches the polarization state of the display light, an imaging optical system that forms the virtual image by emitting first display light in a first polarization state from the exit through a first optical path having a first optical path length, and forms the real image by emitting second display light in a second polarization state from the exit through a second optical path having a second optical path length longer than the first optical path length, and a polarization state of the display light by the polarization control element, and a control unit that controls turning on and off each of the plurality of light sources of the backlight, the control method comprising the steps of: the control unit switching the imaging optical system from the first optical path to the second optical path and switching the display from the virtual image to the real image; and the control unit performing control such that the area of ​​the light source region of the light source mounted on the light source circuit board that is turned on with more intensity than a predetermined intensity when the real image is displayed is larger than the area of ​​the light source region of the light source that is turned on with more intensity than the predetermined intensity when the virtual image is displayed.

[0023] In a seventh aspect, the control unit executes a procedure (step) for controlling the area of ​​the light source that is lit more strongly than a predetermined intensity when a real image is displayed to be larger than the area of ​​the light source that is lit more strongly than a predetermined intensity when a virtual image is displayed. By executing this procedure, for example, the outer edge of the light source area is lit when a real image is displayed, and the outer edge of the light source area that is not visually recognized as a virtual image is turned off when a virtual image is displayed. This makes it possible to improve light utilization efficiency while eliminating the difference in brightness between when a real image is displayed and when a virtual image is displayed, while suppressing waste. In this way, when one of a real image and a virtual image is displayed, the light emitted from the pixel in the direction for displaying the other is suppressed from being wasted, thereby improving light utilization efficiency.

[0024] An eighth aspect is a head-up display device having an outlet, and emitting display light from the outlet toward a light-projecting member to allow a virtual image and a real image of a display image represented by the display light to be viewed, the head-up display device including: a first backlight having a plurality of first light sources mounted thereon; a first display that generates first display light by transmitting illumination light from the first light sources; a second backlight having a plurality of second light sources mounted thereon; and a second display that generates second display light by transmitting illumination light from the second light sources; the head-up display device forming the virtual image by emitting the first display light from the outlet along a first optical path having a first optical path length; and emitting the second display light from the outlet along a second optical path having a second optical path length longer than the first optical path length. a first control unit that controls the turning on and off of each of the first light sources; and a second control unit that controls the turning on and off of each of the second light sources, the method comprising the steps of: when the virtual image is to be displayed using the first display light, the first control unit controls the first light sources to be turned on with intensity stronger than a predetermined intensity; and when the real image is to be displayed using the second display light, the second control unit controls the area of ​​the light sources that are turned on with intensity stronger than the predetermined intensity to be larger than the area of ​​the light sources that are turned on with intensity stronger than the predetermined intensity when the virtual image is to be displayed.

[0025] In an eighth aspect, a head-up display device includes a backlight, a display, and a control unit, each of which has two systems for generating a virtual image and a real image, and which share an imaging optical system. The device is configured to execute a procedure (step) in which a first control unit controls the first light source to be illuminated at a higher intensity than a predetermined intensity when a virtual image is displayed using a first display light, and a second control unit controls the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when a real image is displayed using a second display light, so that the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when a virtual image is displayed is larger than the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when a virtual image is displayed. By executing this procedure, for example, when a real image is displayed, the outer edge of the light source area is illuminated, and when a virtual image is displayed, the outer edge of the light source area that is not viewed as a virtual image is turned off. This can reduce waste and eliminate the difference in brightness between when a real image is displayed and when a virtual image is displayed, thereby improving light utilization efficiency. In this way, when one of a real image and a virtual image is displayed, the light emitted from the pixel in the direction intended to display the other is reduced from being wasted, thereby improving light utilization efficiency.

[0026] Those skilled in the art will easily understand that the exemplified embodiments according to the present invention can be further modified without departing from the spirit of the present invention. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a diagram showing an example of a configuration including an imaging optical system when a virtual image is displayed in a head-up display device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of a configuration including an imaging optical system when a real image is displayed in the head-up display device according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing an example of a lens configuration and an optical path between a backlight and a display when a virtual image is displayed in the head-up display device according to the first embodiment of the present invention. [Figure 4]FIG. 3 is a diagram showing an example of a lens configuration and an optical path between a backlight and a display when a real image is displayed in the head-up display device according to the first embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing an example of the configuration of a control system of the head-up display device according to the first embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart showing an example of the operation of the control system of the head-up display device in the first embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing the direction of light emitted by each of multiple light sources mounted on a light source circuit board of a backlight when the head-up display device in the first embodiment of the present invention displays a virtual image and a real image, when viewed from the normal direction. [Figure 8] FIG. 8 is a diagram showing an example of a first light source lighting pattern of a plurality of light sources mounted in a backlight when a virtual image is displayed and when a real image is displayed in the head-up display device according to the first embodiment of the present invention. [Figure 9] FIG. 9 is a diagram showing a second light source lighting pattern of a plurality of light sources mounted in a backlight when a virtual image is displayed and when a real image is displayed in the head-up display device according to the first embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing a third light source lighting pattern of a plurality of light sources mounted in the backlight when the head-up display device according to the first embodiment of the present invention displays a virtual image and a real image. [Figure 11] FIG. 11 is a diagram showing a fourth light source lighting pattern of a plurality of light sources mounted in the backlight when the head-up display device according to the first embodiment of the present invention displays a virtual image and a real image. [Figure 12] FIG. 12 is a diagram showing an example of a configuration including an imaging optical system when a virtual image is displayed in a head-up display device according to the second embodiment of the present invention. [Figure 13] FIG. 13 is a diagram showing an example of the configuration of a control system of a head-up display device according to the second embodiment of the present invention. [Figure 14] FIG. 14 is a flowchart showing an example of the operation of the control system of the head-up display device in the second embodiment of the present invention. [Figure 15] FIG. 15 is a diagram cited to explain the direction of light irradiation from the light source, where (A) shows when a virtual image is displayed and (B) shows when a real image is displayed. DETAILED DESCRIPTION OF THE INVENTION

[0028] The best mode described below is used to facilitate understanding of the present invention, and therefore, those skilled in the art should be aware that the present invention is not unduly limited by the embodiments described below.

[0029] (Configuration of the first embodiment) A first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a diagram showing a configuration in which a virtual image is generated in a head-up display device (hereinafter, simply referred to as HUD device 1A unless otherwise specified) according to the first embodiment, and Fig. 2 is a diagram showing a configuration in which a real image is generated.

[0030] 1 and 2, the HUD device 1A includes a backlight 11 mounted with a light source (e.g., 14 in FIGS. 7(A) and 7(B)) that emits white light and is made of light-emitting diodes that emit light in the visible wavelength range mounted on a light source circuit board (e.g., see 140 in FIGS. 7(A) and 7(B)), a display 12 that generates an image using light incident from the backlight 11 (light source 14) and displays the image by switching the polarization of the emitted light between a first polarization (first polarization state) and a second polarization (second polarization state) that are different from each other, and The device includes an imaging optical system 13 having a plurality of mirrors (reflecting members) that reflect display light L (first display light L1 that represents a display image of a virtual image VI, and second display light L2 that represents a display image of a real image RI in the case of FIG. 2) that represents a display image displayed on the display device 12 toward a windshield WS that is a light-projecting member, and a control unit 15 that controls the display content on the display device 12, controls switching between the first polarized light and the second polarized light, and controls turning on and off of a plurality of light sources 14 of the backlight 11, and these are housed in a housing 16. The housing 16 is provided with an exit port 17 (opening) through which the display light L is emitted, and a cover glass 18 is placed at the exit port 17 to protect the interior.

[0031] The imaging optical system 13 forms a virtual image VI by emitting first display light L1 in a first polarization state (first polarization) from an exit port 17 along a first optical path OP1 having a first optical path length, and forms a real image RI (see FIG. 2) by emitting second display light L2 in a second polarization state (second polarization) from the exit port 17 along a second optical path OP2 having a second optical path length longer than the first optical path length. To this end, the imaging optical system 13 includes a first mirror 131, a second mirror 132, and a third mirror 133, each having a concave shape. The first mirror 131 reflects the first display light L1 (which has a first polarization) and transmits the second display light L2 (which has a second polarization). The second mirror 132 is a mirror that reflects the second display light L2 that transmits through the first mirror 131. The display lights (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 emitted onto the windshield WS, allowing the occupant DR to view the respective display images.

[0032] For this reason, the first optical path OP1 passes through the backlight 11 (light source 14), the display 12, the first mirror 131, the third mirror 133, the exit port 17, and the windshield WS, and the second optical path OP2 passes through the backlight 11 (light source 14), the display 12, the first mirror 131, the second mirror 132, the third mirror 133, the exit port 17, and the windshield WS and is viewed by the occupant DR, so the optical path length of the second optical path OP2 is longer by the amount that it passes through the second mirror 132. Note that in Figures 1 and 2, although countless light rays would normally be emitted from the display 12, for ease of explanation, the light that is emitted from the center of the display 12 and passes through the center of the eyebox will be referred to as a representative ray and denoted by the symbol L. In addition, in Figures 1 and 2, as well as Figures 7(A) and (B) described below, the representative light ray emitted from the center of the display 12 is shown by a solid line, the light ray emitted from the upper end of the display 12 is shown by a dashed line, and the light ray emitted from the lower end of the display 12 is shown by a dashed line.

[0033] The HUD device 1A of the first embodiment of the present invention is disposed below the windshield WS of a vehicle C (for example, inside an instrument panel), and emits display light L (first display light L1, second display light L2) and projects it onto the windshield WS. The display light L is generated by a backlight 11 (light source 14) and a display 12 inside the HUD device 1A. The display light L emitted from the display 12 travels through an imaging optical system 13 and is emitted from an emission port 17 of a housing 16 through a cover glass 18. By viewing the display light L reflected by the windshield WS, an occupant DR of the vehicle C can view a virtual image VI on the far side of the windshield WS as shown in FIG. 1 and a real image RI on the near side as shown in FIG. 2.

[0034] The virtual image VI shown in FIG. 1 displays information that is highly necessary to draw the occupant DR's attention, such as vehicle information such as the vehicle speed and engine RPM of the vehicle C, route guidance displays such as turn-by-turn directions and maps, blind spot indicators, and warning displays such as speed limit exceeding warnings, on the other side of the windshield WS as viewed from the occupant DR. The real image RI shown in FIG. 2 displays, for example, entertainment content, assistants and agents supporting the occupant DR, and characters representing them on the front side of the windshield WS as viewed from the occupant DR. These displays provide a driving environment that reduces the need to move the viewpoint and adjust the focal length of the eyes. The virtual image VI and real image RI include background portions as well as characters and icons indicating this information, and are, for example, approximately rectangular in shape when viewed in a planar view from the occupant DR.

[0035] The display 12 includes, for example, a TFT (Thin Film Transistor) display element 121 (see FIG. 5 ), and a polarization control element 122 that is disposed closer to the exit 17 along the optical path than the display element 121 and that switches the polarization of the emitted display light L between first and second polarizations that are different from each other. Note that, for example, the first polarization may be S polarization and the second polarization may be P polarization, or vice versa. Furthermore, the first polarization and the second polarization are not limited to S polarization and P polarization, and any polarization angles different from each other are acceptable; for example, it is desirable that the polarization angles differ by at least 22.5 degrees.

[0036] Furthermore, as shown in Figures 1 and 2, it is desirable that the display 12 be arranged at an angle with respect to the axis (optical axis) of the light rays of the display light L in order to eliminate stray light (light leaking from the light source 14 of the backlight 11) and external light (light entering from outside) from the optical path of the display light L.

[0037] The display element 121 is connected to a display control unit 151 in Fig. 5, which will be described later, and forms light that represents a figure of any shape in accordance with a signal sent from the display control unit 151. The polarization control element 122 extracts only light of a specific polarization, specifically the first polarization or second polarization described above, from the light beams emitted from the display element 121, and controls the switching between them. The polarization control element 122 is connected to a display drive unit 152 as shown in Fig. 5, which will be described later, and switches the polarization in accordance with a signal sent from the display drive unit 152.

[0038] The polarization control element 122 may switch the polarization by electrical processing, or may switch the polarization by arranging a polarizing plate (see 117 in FIGS. 3(A) and 3(B) described later) or a wavelength plate on the exit 17 side of the polarization control element 122, and physically rotating the central axis at a predetermined angle with the optical axis direction as the central axis. In either case, the polarization is switched under the control of the display drive unit 152.

[0039] Here, for example, the first polarized light is S-polarized light (S-polarized light relative to the first mirror 131), the second polarized light is P-polarized light (P-polarized light relative to the first mirror 131), the first mirror 131 is a mirror that reflects S-polarized light toward the first mirror 131 and transmits P-polarized light toward the first mirror 131, and the second mirror 132 is a mirror that reflects P-polarized light toward the first mirror 131 and transmits S-polarized light toward the first mirror 131. In this configuration, the first display light L1, which is S-polarized light, is reflected by the first mirror 131 and guided to the third mirror 133. The second display light L2, which is P-polarized light, is transmitted through the first mirror 131, reflected by the second mirror 132, and guided to the third mirror 133. By setting such a configuration of the imaging optical system 13 and the polarizations of the display lights (first display light L1, second display light L2), it is possible to generate different display images for the display lights L1 and L2.

[0040] 2, by positioning the optical focus F closer to the outlet 17 than the first mirror 131, it becomes possible to display the real image RI at any appropriate position in front of the occupant DR. That is, when the optical focus F is positioned closer to the display 12 than the first mirror 131, the optical focus F becomes farther away from the second mirror 132, and as the distance increases, the real image RI is displayed at a position closer to the occupant DR and in a larger size, making it difficult for the occupant DR to see the real image RI. That is, it is preferable that the optical focus F is closer to the second mirror 132. For this reason, in the HUD device 1A of the first embodiment, the imaging optical system 13 is disposed so that the optical focus F is located at least between the first mirror 131 and the second mirror 132.

[0041] The control unit 15 controls the polarization state of the display light L by the polarization control element 122 and the turning on and off of each of the light sources 14. The control unit 15 controls the area of ​​the light source 14 that is turned on with more intensity than a predetermined intensity when displaying the real image RI to be larger than the area of ​​the light source 14 that is turned on with more intensity than a predetermined intensity when displaying the virtual image VI. The configuration and operation of the control unit 15 will be described later with reference to FIGS. 5 and 6.

[0042] Next, reference is made to Figures 3(A) and 3(B). Figure 3(A) shows the lens configuration and optical path in the H direction when a virtual image VI is displayed, and Figure 3(B) shows the lens configuration and optical path in the V direction. In Figures 3(A) and 3(B), light emitted from an LED (here, 111) serving as the backlight 11 (light source 14) is converted into collimated light that is approximately parallel to the optical axis in both the H and V directions by a condenser lens 113. The light-receiving surface of the first lenticular lens 114 on the LED 111 side has a structure in which a plurality of cylindrical lenses, each having a convex curved surface facing the LED 111 side in a cross section taken along the V direction, are arranged in parallel along the V direction. The exit surface of the first lenticular lens 114 has a structure in which a plurality of cylindrical lenses, each having a convex curved surface facing the exit side of the second display light L2 in a cross section taken along the V direction, are arranged in parallel along the V direction. With this structure, the first lenticular lens 114 condenses the light from the LED 111 in the V direction to form a multiplexed image.

[0043] The light receiving surface of the second lenticular lens 115 on the LED 111 side has a structure in which multiple cylindrical lenses, each having a convex curved surface facing the LED 111 side in the H direction, are arranged in parallel along the H direction. The light exit surface of the second lenticular lens 115 is a toroidal surface that is concave in both the V and H directions. With this configuration, the second lenticular lens 115 collects light from the LED 111 in the H direction to form a multiplexed image, and also aligns the direction of the light with the downstream imaging optical system 13 (see Figures 1 and 2). This second lenticular lens 115 for displaying a virtual image VI is referred to as a first lens 115a.

[0044] The second display light L2 emitted from the first lens 115a is diffused by a diffuser 117 (not shown in FIG. 1) to reduce uneven brightness. The second display light L2 diffused by the diffuser 117 is incident on the liquid crystal panel 116, which is the display device 12, and generates an image in accordance with the control of a control board (control unit 15 in FIG. 1), which is then emitted to a first mirror 131 of the downstream imaging optical system 13. This lens configuration and optical path enable the occupant DR to view the virtual image VI with appropriate brightness and uniformity.

[0045] 4(A) and 4(B) are diagrams showing an example of the lens configuration and optical path (second optical path OP2) when a real image RI is displayed in the HUD device 1A of this embodiment. FIG. 4(A) shows the lens configuration and optical path in the H direction, and FIG. 4(B) shows the lens configuration and optical path in the V direction. In FIGS. 4(A) and 4(B), the condenser lens 113 and the first lenticular lens 114 have the same configuration as in FIG. 2. That is, the condenser lens 113 converts the light emitted from the LED 111 into parallel light in both the H and V directions, and the first lenticular lens 114 collects the light from the LED 111 in the V direction to form a multiplexed image.

[0046] The second lenticular lens 115 also has the same function as the second lenticular lens 115 shown in FIG. 3A in that it focuses the light from the LED 111 in the H direction to form a multiplexed image. Therefore, the light-receiving surface on the LED 111 side has a structure similar to that shown in FIG. 3A in that multiple cylindrical lenses, each having a convex curved surface facing the LED 111 in the H direction, are arranged side by side along the H direction. The light exit surface, on the other hand, is a toroidal surface convex in both the V and H directions to achieve a desired light distribution characteristic (the light source 14 (here, the LED 111) for displaying the real image RI irradiates illumination light so as to converge onto the display device 12 for displaying the real image RI, while the light source 14 for the virtual image VI irradiates illumination light so as to diverge onto the display device 12). The convex shape of the light exit surface narrows the light distribution characteristic in both the H and V directions. This second lenticular lens 115 for displaying the real image V1 is referred to as the second lens 115b.

[0047] The first display light L1 emitted from the second lens 115b is diffused by a diffuser 117 (not shown in FIG. 1) to reduce brightness unevenness, and then enters the display device 12 (here, the LCD 111). An image (first display light L1) is generated under the control of the control board (control unit 15), and the image is then emitted from the first mirror 131 of the downstream imaging optical system 13. As shown in FIGS. 4A and 4B, when a real image RI is to be displayed, the optical axes in the H and V directions intersect between the windshield WS and the viewpoint EB (eye box) of the occupant DR, who is the viewer, to generate the real image RI. The intersection of the optical axes in this case can be set arbitrarily depending on the position and magnification of the real image RI to be displayed. This lens configuration and optical path enable the occupant DR to view the real image RI with appropriate brightness and uniformity.

[0048] Fig. 5 is a functional block diagram showing the configuration of an image generation unit (hereinafter referred to as PGU: Picture Generation Unit) in a HUD device 1A according to a first embodiment of the present invention. Note that Fig. 5 shows only the minimum necessary configuration directly related to the present invention, and other well-known configurations are omitted. In Fig. 5, a PGU 10 includes a control unit 15 shown in Figs. 1 and 2, a backlight 11 (light source 14), and a display unit 12 (the same as the display 12 in Figs. 1 and 2). The control unit 15 includes a display control unit 151 that issues an instruction to the display unit 12 to generate light representing a figure of any shape based on information sent from various devices 30 such as a vehicle speed sensor, a navigation device, a RADAR (Radio Detecting and Ranging), and a LiDAR (Laser Imaging Detection and Ranging), and a display drive unit 152 that generates an image using light irradiated from the multiple light sources 14 of the backlight 11 based on a signal sent from a switch 20 that switches the driving mode (manual driving, autonomous driving) of the vehicle C, switches the polarization of the emitted light between different first and second polarization states, and controls the switching of the polarization direction of the display unit 12 that generates display light (first display light L1, second display light L2) representing a display image.

[0049] The control unit 15 also includes a light source driving unit 153 that controls the supply of power required to turn on and off the light sources 14 mounted on a light source circuit board 140 (see FIG. 7(A)) of the backlight 11. The light source driving unit 153 controls the ON / OFF timing of each LED (see 111 in FIGS. 3(A)(B) and 4(A)(B)) mounted on the light source circuit board 140 as the light source 14 and the value of the current (current value) flowing through each LED 111, and also controls the voltage supplied to the light source 14, thereby improving power efficiency.

[0050] The display unit 12 includes a TFT-type display element 121 that generates display light (first display light L1, second display light L2) that displays a graphic of any shape based on a signal transmitted from a display control unit 151, and a polarization control element 122 that switches the emitted display light L between the first display light L1 of a first polarization and the second display light L2 of a second polarization in accordance with a signal transmitted from a display drive unit 152. In the configuration of FIG. 5, for example, during manual driving, the display drive unit 152 controls the polarization control element 122 to emit the first display light L1 of the first polarization. At this time, the display control unit 151 controls the polarization control element 121 to generate the first display light L1 that displays vehicle information, route guidance information, warning displays, etc. Furthermore, for example, during autonomous driving, the display drive unit 152 controls the polarization control element 122 to emit the second display light L2 of the second polarization. At this time, the display control unit 151 controls the display element 121 to generate second display light L2 that represents an assistant or agent that supports the driving of the occupant DR, or a character representing such an assistant or agent.

[0051] In this way, when it is desired to display a virtual image VI in the HUD device 1A of the first embodiment of the present invention, the display unit 12, which controls polarization, sets the polarization state of the backlight 11 (light source 14) to a polarization state (first polarization) that is reflected by the first mirror 131 of the imaging optical system 13, so that the first display light L1 is reflected by the third mirror 133 and enters the windshield WS, and is reflected by the windshield WS to become a virtual image VI that can be displayed on the outside of the vehicle across the windshield WS (an imaging area that is virtually set in front of the vehicle C and is set at an angle with respect to the road surface) (see optical path OP1 in Figure 1). On the other hand, when it is desired to display a real image RI, the display unit 12, which controls polarization, sets the polarization state of the backlight 11 (light source 14) to a polarization state (second polarization) that is transmitted by the first mirror 131 of the imaging optical system 13, so that the second display light L2 is reflected by the second reflecting mirror 132 and incident on the third mirror 133, is further reflected by the third mirror 133 and incident on the windshield WS, is reflected by the windshield WS, and becomes a real image RI that can be displayed on the passenger compartment side in front of the occupant DR across the windshield WS (an imaging area that is virtually set when the vehicle is standing perpendicular to the road surface) (see the second optical path OP2 in Figure 1).

[0052] That is, for example, the imaging area of ​​the virtual image VI, which is at an angle of less than 45 degrees with the road surface, looks like the display content is unfolded on the road surface, so when performing navigation, the display content appears to be superimposed on the road surface, which has the advantage of enabling intuitive information presentation. On the other hand, the imaging area of ​​the real image RI, which is at an angle of 45 degrees or more with the road surface, is expected to be used in situations such as autonomous driving and watching entertainment content while stopped, and has the advantage of improving visibility by being displayed while standing in front of the road surface.

[0053] The control unit 15 further improves power efficiency by controlling the light source driving unit 153 to control the ON / OFF timing of each LED (see 111 in FIGS. 3(A) and 3(B) and 4(A) and 4(B)) mounted on the light source circuit board 140 as the light source 14, the value of the current flowing through each LED 111, and the voltage supplied to the light source 14. The light source driving unit 153 controls the area of ​​the light source 14 that is lit with more intensity than a predetermined intensity when displaying a real image RI, so that it is larger than the area of ​​the light source 14 that is lit with more intensity than the predetermined intensity when displaying a virtual image RI. Here, the "predetermined intensity" refers to the emission intensity set in a default state of light irradiated onto the display 12 (display unit) from a backlight equipped with multiple light sources when displaying a virtual image VI or a real image RI. Here, the emission intensity is controlled by the area of ​​the light source 14 that is lit. That is, when a real image RI is displayed, the area of ​​light source 14 that is turned on with more intensity than a predetermined intensity is controlled to be larger than the area of ​​light source 14 that is turned on with more intensity than a predetermined intensity when a virtual image VI is displayed. Furthermore, the "area of ​​the light source that is turned on" refers to the mounting area on light source circuit board 140 of the light source that is turned on among the plurality of light sources 14 mounted on light source circuit board 140 (backlight) (lighting area A when a virtual image is generated, lighting area B when a real image is generated), for example, as shown in Fig. 8 described later.

[0054] (Operation of the first embodiment) Please refer to Fig. 6. Fig. 6 is a flowchart showing an example of the operation of the control system of the HUD device 1A according to the first embodiment of the present invention, specifically, the control unit 15. Also, Fig. 8 is a diagram showing an example of a first light source lighting pattern of the plurality of light sources 14 mounted on the backlight 11 when a virtual image VI is displayed and when a real image RI is displayed. Hereinafter, with reference to Figs. 6 and 8, the operation of the control system (PGU 10, mainly the control unit 15) of the HUD device 1A shown in Fig. 5 will be described in detail.

[0055] In the PGU 10, the control unit 15 (display drive unit 152) first determines whether the vehicle C is being manually driven or automatically driven based on a signal transmitted from the switch 20 that switches the driving mode (manual driving, automatic driving) of the vehicle C (step ST101). If it is determined that the vehicle C is being manually driven (step ST101 “M”), the control unit 15 (display control unit 151) controls the display element 121 of the display 12 to generate a first display light L1 (virtual image VI) that displays vehicle information, route guidance information, warning displays, etc. (step ST102). At this time, the control unit 15 (display drive unit 152) controls the imaging optical system 13 so that the first display light L1, which is a 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 emission port 17 toward the windshield WS along a first optical path OP1 (step ST103).

[0056] Next, the control unit 15 (light source driving unit 153) controls the backlight 11 to turn on at least some of the LEDs 111 as the multiple light sources 14 (step ST104), and the display unit 12 (display device 12) emits (projects) the generated first display light L1 (virtual image VI) toward the windshield WS via the imaging optical system 13 (first optical path OP1) and the emission port 17 (step ST108).

[0057] On the other hand, if the vehicle C is in autonomous driving (step ST101 “A”), the control unit 15 (display control unit 151) controls the display element 121 to generate second display light L2 representing an assistant, agent, or character representing them that supports the driving of the occupant DR (step ST105). At this time, the control unit 15 (display drive unit 152) controls the imaging optical system 13 to emit the second display light L2, which is the second polarization, via the polarization control element 122. That is, the control unit 15 controls to switch the optical path of the imaging optical system 13 from the first optical path OP1 to the second optical path OP2 so that the second display light L2 is projected from the emission port 17 toward the windshield WS on the second optical path OP2 (step ST106).

[0058] Next, the control unit 15 (light source driving unit 153) performs control to increase the area of ​​the light source 14 to be turned on compared to the area to be turned on when the virtual image VI is displayed (step ST107). Specifically, for example, as shown in Fig. 8, the control unit 15 performs control to increase the area of ​​the light source 14 mounted on the light source circuit board 140 of the backlight 11 that is turned on at a higher intensity than a predetermined intensity when the real image RI is displayed (a region B turned on when the real image is generated) along the long side direction H of the rectangular area of ​​the display 12 compared to the area of ​​the light source mounted on the light source circuit board 140 that is turned on at a higher intensity than a predetermined intensity when the virtual image VI is displayed (a region A turned on when the virtual image is generated). Conversely, when switching from the real image RI to the virtual image VI, the control unit 15 performs control to turn off the light source 14 that was used when the real image VI was displayed, for example, mounted in the outer edge region in the long side direction of the rectangular area of ​​the display 12.

[0059] Finally, the display unit 12 (display device 12) projects the generated second display light L2 (real image V1) toward the windshield WS, which is a light-projecting member, via the imaging optical system 2 (second optical path OP2) and the exit port 17 (step ST108). In this way, the control unit 15 controls the area of ​​the light source 14 that is turned on stronger than a predetermined intensity when displaying the real image RI to be larger than the area of ​​the light source 14 that is turned on stronger than a predetermined intensity when displaying the virtual image VI. This prevents the light emitted from the pixel in the direction for displaying the other (virtual image) when one of the real image RI and the virtual image VI (real image) is displayed from being wasted, thereby improving light utilization efficiency. Therefore, when one of the real image RI and the virtual image VI is displayed, the light emitted from the pixel in the direction for displaying the other (virtual image) is prevented from being wasted, thereby improving light utilization efficiency.

[0060] 7 shows the irradiation directions of light rays from each light source 4 (LEDs 111 shown in FIGS. 3 and 4 ) when the light sources 140 mounted on the light source circuit board 140 of the backlight 11 are viewed from the normal direction when a virtual image VI is displayed and a real image RI is displayed in the HUD device 1A of the first embodiment of the present invention. When the control unit 15 switches the display from the virtual image VI to the real image RI, for example, as shown in FIG. 7(B), when the control unit 15 switches the display from the virtual image VI to the real image RI, the control unit 15 controls the light sources 14 (light rays indicated by solid arrows in the figure) arranged in the mounting area (outer edge areas Y1 and Y2 of the light source circuit board 140) that does not overlap with the display device 12 when the light source circuit board 140 of the backlight 11 on which the light sources 14 are mounted is viewed from the normal direction, to light up with a stronger intensity than a predetermined intensity. This prevents the wasting of light emitted from the pixel in the direction for displaying the virtual image VI when one of the real image VI and the virtual image RI (real image RI) is displayed, thereby improving light utilization efficiency. In FIGS. 7A and 7B, solid arrows indicate light rays used for display, and dashed arrows indicate light rays not used for display.

[0061] In addition, Figures 8 to 11 show four examples (first light source lighting pattern to fourth light source lighting pattern) of light source lighting patterns of the multiple light sources 14 implemented in the backlight 11 when displaying a virtual image V1 and a real image RI in the HUD device 1A of the first embodiment of the present invention.

[0062] In the first light source pattern shown in Fig. 8, for example, as shown in Fig. 8, control unit 15 performs control to increase the area of ​​light sources 14 mounted on light source circuit board 140 of the backlight that are turned on with more intensity than a predetermined intensity when a real image is displayed (area B lit when a real image is generated) along the long side direction H of the rectangular area of ​​the display device compared to the area of ​​light sources mounted on light source circuit board 140 that are turned on with more intensity than a predetermined intensity when a virtual image is displayed (area A lit when a virtual image is generated). Alternatively, when switching from real image display to virtual image display, control may be performed to turn off light sources 14 at the edge (one row above and below) of area B lit when a real image is generated in the short side Y direction, as shown in the second light source lighting pattern in Fig. 9.

[0063] 10(A) and 10(B), the control unit 15 controls the area of ​​the light source 14 mounted on the light source circuit board 140 of the backlight 11, which is turned on with a higher intensity than a predetermined intensity when a real image RI is displayed (the area B lit when a real image is generated), to be larger along both the long side direction (H) and the short side direction (V) of the rectangular area of ​​the display than the area of ​​the light source 14 mounted on the light source circuit board 140, which is turned on with a higher intensity than a predetermined intensity when a virtual image VI is displayed (the area A lit when a virtual image is generated). Therefore, when one of a real image or a virtual image is displayed, the light emitted from the pixel in the direction for displaying the other image is prevented from being wasted, thereby improving light utilization efficiency. In addition to the lighting patterns of the light sources 14 shown in Figures 10(A) and (B), other control may be performed, such as (1) turning off all of the light sources 14 arranged on the outer edge of the light source circuit board 140, (2) turning off the light sources 14 arranged on one edge, (3) turning off the light along one edge of both the long side H and the short side, or (4) turning off some of the light sources 14 when a real image is displayed and turning on some of the light sources 14 that were turned off when the real image was displayed when a virtual image was displayed.

[0064] In the third light source lighting pattern shown in Figures 10(A) and (B), the control unit 15 controls the area of ​​the light source 14 mounted on the light source circuit board 140 of the backlight 11, which is lit at a higher intensity than a predetermined intensity when a real image RI is displayed (lighting area B when a real image is generated), to be larger along each of the long side direction (H) and short side direction (V) of the rectangular area of ​​the display 12 than the area of ​​the light source 14 mounted on the light source circuit board 140, which is lit at a higher intensity than a predetermined intensity when a virtual image is displayed (lighting area A when a virtual image is generated).At this time, as a fourth light source lighting pattern, by controlling the area of ​​the light source 14 to be increased in the long side direction H than in the short side direction V, when one of the real image RI or the virtual image VI is displayed, the wasted light emitted from the pixel in the direction for displaying the other is suppressed, and the light utilization efficiency can be more efficiently improved.

[0065] Furthermore, as shown in FIG. 11, the control unit 15 may control the light sources 14 to be all lit when a real image RI is displayed (area A lit when a real image is generated), but to also turn off a portion of the light sources 14 mounted inside the light source circuit board 140 excluding the outer edge portion in the short side direction (area B lit when a virtual image is generated, surrounded by a dashed line) when a virtual image VI is displayed.

[0066] (Effects of the first embodiment) As described above, the head-up display device 1A of the first embodiment is a head-up display device (HUD device 1A) that has an emission port 17, as shown in Figures 1 and 2, and emits display light L from the emission port 17 toward a light-projecting member (windshield WS), thereby allowing a virtual image VI and a real image RI of the display image represented by the display light L1 to be visually recognized. The HUD device 1A includes a backlight 11 having a plurality of light sources (see 14 in Figures 7(A) and (B)), a display 12 that generates display light L by transmitting illumination light emitted by the light sources 14, a polarization control element 122 that switches the polarization state of the display light L, an imaging optical system 13 that forms a virtual image VI by emitting first display light L1 in a first polarization state from an exit 17 along a first optical path OP1 having a first optical path length, and forms a real image RI by emitting second display light L2 in a second polarization state from the exit 17 along a second optical path OP2 having a second optical path length longer than the first optical path length, and a control unit 15 that controls the polarization state of the display light L by the polarization control element 122 and the turning on and off of each of the light sources 14. The control unit 15 controls the area of ​​the light source 14 that is lit with more intensity than a predetermined intensity when displaying the real image RI to be larger than the area of ​​the light source 14 that is lit with more intensity than a predetermined intensity when displaying the virtual image VI.

[0067] In the HUD device 1A of the first embodiment of the present invention, the control unit 15 controls the area of ​​the light source 14 that is illuminated with a higher intensity than a predetermined intensity when displaying a real image RI to be larger than the area of ​​the light source 14 that is illuminated with a higher intensity than a predetermined intensity when displaying a virtual image VI. For example, when displaying a real image, the control unit 15 illuminates the outer edge of the light source area, while when displaying a virtual image, the control unit 15 extinguishes the outer edge of the light source area that is not perceived as a virtual image. This can reduce waste, eliminate the difference in brightness between when displaying a real image RI and when displaying a virtual image VI, and improve light utilization efficiency. In this way, when displaying one of a real image or a virtual image, the light emitted from the pixel in the direction intended to display the other is prevented from being wasted, thereby improving light utilization efficiency.

[0068] Furthermore, according to the HUD device 1A of the first embodiment of the present invention, when the control unit 15 switches the display from a virtual image VI to a real image RI, for example, as shown in FIG. 7(B), when the light source circuit board 140 of the backlight 11 on which the light source 14 is mounted is viewed from the normal direction, the control unit 15 controls the light source 14 (light rays indicated by solid arrows in the figure) arranged in an implementation area (outer edge areas Y1, Y2 of the light source circuit board 140) that does not overlap with the display 12 to light up at a stronger intensity than a predetermined intensity. This prevents the light emitted from the pixel in the direction to display the other image (virtual image V1 in this case) when one of the real image RI and the virtual image VI (the real image in this case) is displayed from being wasted, thereby improving light utilization efficiency.

[0069] Furthermore, according to the HUD device 1A of the first embodiment of the present invention, the control unit 11 controls the area of ​​the light sources 14 mounted on the light source circuit board 140 of the backlight 11, which are illuminated at a higher intensity than a predetermined intensity when a real image RI is displayed (a real image generation illumination region B), to be larger along the long side direction H of the rectangular area of ​​the display 12 than the area of ​​the light sources 14 mounted on the light source circuit board 140, which are illuminated at a higher intensity than a predetermined intensity when a virtual image VI is displayed (a virtual image generation illumination region A). Alternatively, when switching from a real image RI display to a virtual image VI, the control unit 11 controls the light sources 14 at the edge portions (one row above and below) of the real image RI generation illumination region B in the short side Y direction to be turned off, as shown in FIG. 9. This prevents the light emitted from pixels in a direction for displaying either a real image RI or a virtual image VI from being wasted when the other is displayed, thereby improving light utilization efficiency.

[0070] 10(A) and 10(B), the control unit 15 controls the area of ​​the light source 14 mounted on the light source circuit board 140 of the backlight 11, which is illuminated with more light than a predetermined intensity when a real image RI is displayed, (a real image generation illumination area B), to be larger along both the long side direction (H) and the short side direction (V) of the rectangular area of ​​the display 12 than the area of ​​the light source 14 mounted on the light source circuit board 140, which is illuminated with more light than a predetermined intensity when a virtual image VI is displayed (a virtual image generation illumination area A). Therefore, when one of a real image or a virtual image is displayed, the light emitted from the pixel in the direction for displaying the other image is prevented from being wasted, thereby improving light utilization efficiency. In addition to the lighting patterns of the light sources 14 shown in Figures 10(A) and (B), other control may be performed, such as (1) turning off all of the light sources 14 arranged on the outer edge of the light source circuit board 140, (2) turning off the light sources 14 arranged on one edge, (3) turning off the light along one edge of both the long side H and the short side, or (4) turning off some of the light sources 14 when a real image RI is displayed, and turning on some of the light sources 14 that were turned off when a real image RI was displayed when a virtual image VI was displayed.

[0071] Furthermore, according to the HUD device 1A of the first embodiment of the present invention, the control unit 15 controls the area of ​​the light source 14 mounted on the light source circuit board 140 of the backlight 11, which is illuminated at a higher intensity than a predetermined intensity when a real image RI is displayed, (area B illuminated when a real image is generated) to be larger along each of the long side direction (H) and short side direction (V) of the rectangular light source circuit board 140 of the display 12 than the area of ​​the light source 14 mounted on the light source circuit board 140, which is illuminated at a higher intensity than a predetermined intensity when a virtual image VI is displayed, as shown in Figures 10(A) and 10(B).In this case, by controlling the area of ​​the light source 14 to be larger in the long side direction H than in the short side direction V, when one of the real image RI and the virtual image VI is displayed, the wastage of light emitted from the pixel in the direction for displaying the other is suppressed, and light utilization efficiency can be more efficiently improved.

[0072] A control method for a head-up display device in a first embodiment of the present invention is a control method for a HUD device 10A including, for example, as shown in Figures 1 and 2, a backlight 11 having a light source mounting substrate 140 on which a plurality of light sources 14 are mounted, a display 12 that generates display light L by transmitting illumination light from the light sources 14 of the backlight 11, a polarization control element 122 that switches the polarization state of the display light L, an imaging optical system 13 that forms a virtual image VI by emitting first display light L1 in a first polarization state from an exit 17 along a first optical path OP1 having a first optical path length, and that forms a real image RI by emitting second display light L2 in a second polarization state from the exit 17 along a second optical path OP2 having a second optical path length longer than the first optical path length, and a control unit 15 that controls the polarization state of the display light L by the polarization control element 122 and the turning on and off of each of the plurality of light sources 14 of the backlight 11. The control method includes the steps of the control unit 15 of the HUD device 1A switching the imaging optical system 13 from the first optical path OP to the second optical path OP2, for example, as shown in FIG. 6, and switching the display from the virtual image VI to the real image RI (see ST106), and the control unit 15 controlling the area of ​​the light source 14 mounted on the light source circuit board 140, which is lit with more intensity than a predetermined intensity when the real image RI is displayed, to be larger than the area of ​​the light source 14, which is lit with more intensity than the predetermined intensity when the virtual image RI is displayed (see ST107).

[0073] According to the control method for HUD device 10A of the first embodiment of the present invention, control unit 15 executes a procedure (step ST107) of controlling light sources 14 to be illuminated with a higher intensity than a predetermined intensity when displaying real image RI, so as to be larger than the area of ​​light sources 14 to be illuminated with a higher intensity than a predetermined intensity when displaying virtual image VI. This control, for example, turns on the outer edge of the light source area when displaying real image RI, and turns off the outer edge of the light source area that is not visually recognized as virtual image VI when displaying virtual image VI. This eliminates the difference in brightness between when a real image is displayed and when a virtual image is displayed, while suppressing waste, thereby improving light utilization efficiency. In this way, when one of real image RI and virtual image VI is displayed, the light emitted from pixels in the direction intended to display the other is suppressed from being wasted, thereby improving light utilization efficiency.

[0074] (Configuration of the second embodiment) Fig. 12 is a diagram showing an example of a configuration including an imaging optical system of HUD device 1B according to a second embodiment of the present invention. Fig. 13 is a diagram showing an example of a configuration of a control system of HUD device 1B according to the second embodiment of the present invention, and Fig. 14 is a flowchart showing an example of an operation of the control system of HUD device 1B according to the second embodiment of the present invention. The configuration and operation of HUD device 1B according to the second embodiment of the present invention will be described in detail below with reference to Figs. 12 to 14.

[0075] Please refer to Fig. 12. HUD device 1B of the second embodiment shown in Fig. 12 differs from HUD device 1A of the first embodiment shown in Fig. 1 and Fig. 2 in that HUD device 1B of the second embodiment has two systems each of backlight 11, display 12, and control unit 15 that HUD device 1A of the first embodiment has, and therefore, the lenses that make up imaging optical system 13 are optimally designed according to the orientation characteristics required for displaying real image RI and virtual image VI, and are controlled independently by the two systems of control unit 15 for displaying real image RI and virtual image VI, respectively.

[0076] As shown in FIG. 12, the HUD device 1B of the second embodiment includes, for example, a first backlight 11a having a plurality of first light sources implemented therein, a first display 12a that generates first display light L1 by transmitting illumination light from the first light source, a second backlight 11b having a plurality of second light sources implemented therein, a second display 12b that generates second display light L2 by transmitting illumination light from the second light source, an imaging optical system 13 that forms a virtual image VI by emitting the first display light L1 in a first polarization state from an exit 17 along a first optical path having a first optical path length, and forms a real image RI by emitting the second display light L2 in a second polarization state from the exit 17 along a second optical path having a second optical path length longer than the first optical path length, a first control unit 15a that controls the turning on and off of each of the first light sources, and a second control unit 15b that controls the turning on and off of each of the second light sources.

[0077] The control units 15a and 15b are included in two image generating units PGU-1 (PGU10a) and PGU-2 (PGU10b), respectively, as shown in FIG. 13, and the first control unit 15a controls the first light source to be illuminated with a higher intensity than a predetermined intensity when a virtual image VI is displayed by the first display light L1, and the second control unit 15b controls the area of ​​the light source illuminated with a higher intensity than the predetermined intensity when a real image RI is displayed by the second display light L2 to be larger than the area of ​​the light source illuminated with a higher intensity than the predetermined intensity when a virtual image RI is displayed.

[0078] 13, the PGU-1 (PGU 10a) includes a backlight 11a (light source 14), a display unit 12a (display), and a control unit 15a. The control unit 15a includes a display control unit 155 that issues a command to the display unit 12a to generate a first display light L1 (virtual image VI) representing a display image based on information or signals transmitted from various devices 30, such as a vehicle speed sensor, a navigation device, a RADAR, or a LiDAR, a display drive unit 156 that generates an image using light emitted from the light source 14 included in the backlight 11a and drives the display element 121 based on a signal transmitted from a switch 20 that switches between the driving modes (manual driving and autonomous driving) of the vehicle C, and a light source drive unit 153 that controls the supply of power required to turn on and off the light source 14 mounted on a light source circuit board 140 (see FIGS. 7(a) and 7(b)) included in the backlight 11a. The light source driving unit 153 controls the ON / OFF timing of each LED mounted on the light source circuit board 140 as the light source 14 and the value of the current (current value) flowing through each LED, and also controls the voltage supplied to the light source 14, thereby improving power efficiency.

[0079] The display unit 12a includes a TFT (Thin Film Transistor) type display element 121 that forms a first display light L1 that represents a figure of any shape based on a signal transmitted from the control unit 15a (display control unit 155). For example, during manual driving, the display drive unit 156 performs switching control, and at this time, the display control unit 155 controls the display element 121 of the display 12 to generate a first display light L1 (virtual image VI) that represents vehicle information, route guidance information, warning displays, etc.

[0080] Although not shown, PGU-2 (PGU 10b) has the same configuration as PGU-1 (PGU 10a) except for the control unit 15b, and includes a backlight 11b (light source 14B), a display unit 12b, and a control unit 15b (all not shown). The control unit 15b includes a light source drive unit 153, a display control unit 155, and a display drive unit 156. The display unit 12b includes a TFT-type display element 121 that generates second display light L2 representing a figure of any shape based on a signal transmitted from the control unit 15b (display control unit 155). For example, during autonomous driving, the display drive unit 156 performs switching control, and at this time, the display control unit 155 controls the display element 121 to generate display light L2 (real image RI) representing an assistant or agent that supports the driving of the occupant DR, characters representing them, etc.

[0081] In addition, when displaying a virtual image VI using the first display light L1, the control unit 15a (light source driving unit 153) of PGU-1 (PGU10a) controls the light source of the backlight 11a to be lit at a stronger intensity than a predetermined intensity, whereas the control unit 15b (light source driving unit 153) of PGU-2 (PGU10b) controls the area of ​​the light source 14B of the backlight 11b to be lit at a stronger intensity than a predetermined intensity when displaying a real image RI using the second display light L2 so that it is larger than the area of ​​the light source to be lit at a stronger intensity than the predetermined intensity when displaying a virtual image VI.

[0082] (Operation of the second embodiment) 14, first, the control unit 15a (display driving unit 152) determines whether the vehicle C is being manually driven or automatically driven based on a signal transmitted from the switch 20 that switches the driving mode (manual driving, automatic driving) of the vehicle C (step ST201). If it is determined that the vehicle C is being manually driven (step ST201 "M"), the control unit 15a (display control unit 151) controls the display element 111 of the display unit 11a to generate a first display light L1 (virtual image VI) that displays vehicle information, route guidance information, warning display, etc. (step ST202). Next, the control unit 15a (light source driving unit 153) controls the lighting of at least a portion of the LEDs 111 serving as the light source of the backlight 11a (here, the front lights) (step ST203), and the display unit 12a (display device 12a) emits the generated first display light L1 (virtual image VI) from the emission port 17 via a first optical path (imaging optical system 13) having a first optical path length, and projects it toward the windshield WS (step ST206).

[0083] On the other hand, if the vehicle C is in autonomous driving (step ST201 “A”), the control unit 15b (display control unit 151) controls the display element 111 of the display unit 12b to generate second display light L2 (real image RI) representing an assistant, agent, or character representing such an assistant or agent that supports the driving of the occupant DR (step ST204). Subsequently, the control unit 15b (light source driving unit 153) performs control to make the area of ​​the light source 14 to be turned on larger than the area to be turned on when the virtual image VI is displayed (step ST205). Specifically, for example, as shown in FIG. 8, the control unit 15b performs control to make the area of ​​the light source 14 mounted on the light source circuit board 140 of the backlight 11b that is turned on with more intensity than a predetermined intensity when the real image RI is displayed (lighting area B when generating a real image) larger along the long side direction H of the rectangular light source circuit board 140 of the display 12 than the area of ​​the light source mounted on the light source circuit board 140 that is turned on with more intensity than a predetermined intensity when the virtual image VI is displayed (lighting area A when generating a virtual image). Conversely, when the display is switched from a real image RI to a virtual image VI, the light source 14 that was used when displaying the real image VI, for example, that was mounted in the outer edge region of the long side of the display 12, is controlled to be turned off.

[0084] Finally, the display unit 12b (display device 12b) projects the generated display light L2 (real image V1) toward the windshield WS via a second optical path (imaging optical system 13) having a second optical path length longer than the first optical path length and an exit port 17 (step ST206).

[0085] In this way, in the HUD device 1B, the backlight 11 includes two systems, one for generating a virtual image VI and one for generating a real image RI, and the image forming optical system 13 is shared. The control unit 15a (first control unit) controls the first light source of the backlight 11a to light up at a higher intensity than a predetermined intensity when displaying the virtual image VI using the first display light L1, and the second control unit 15b controls the area of ​​the second light source that is lighted up at a higher intensity than the predetermined intensity when displaying the virtual image VI when displaying the second display light L2, so that the area of ​​the second light source that is lighted up at a higher intensity than the predetermined intensity when displaying the virtual image VI is larger than the area of ​​the first light source that is lighted up at a higher intensity than the predetermined intensity when displaying the virtual image VI. Therefore, for example, when displaying the real image RI, the control unit lights up the outer edge of the light source area, and when displaying the virtual image VI, the control unit turns off the outer edge of the light source area that is not visible as the virtual image VI. This can reduce waste, eliminate the difference in brightness between when displaying the real image RI and when displaying the virtual image VI, and improve light utilization efficiency. In this way, when one of a real image and a virtual image is being displayed, the light emitted from the pixel in the direction for displaying the other image is prevented from being wasted, thereby improving the light utilization efficiency.

[0086] (Effects of the second embodiment) As described above, the head-up display device of the second embodiment of the present invention is, for example, as shown in FIG. 12, a HUD device 1B that has an outlet 17 and emits display light L from the outlet 17 toward a light-projecting member (windshield WS), thereby allowing a virtual image VI and a real image RI of the display image represented by the display light L to be visually recognized. The HUD device 1B includes a first backlight 11a having a plurality of first light sources implemented therein, a first display 12a that generates first display light L1 by transmitting illumination light from the first light source, a second backlight 11b having a plurality of second light sources implemented therein, a second display 12b that generates second display light L2 by transmitting illumination light from the second light source, an imaging optical system 13 that forms a virtual image V1 by emitting the first display light L1 from an outlet 17 along a first optical path having a first optical path length, and forms a real image RI by emitting the second display light L2 from the outlet 17 along a second optical path having a second optical path length longer than the first optical path length, a first control unit 15a that controls the turning on and off of each of the first light sources, and a second control unit 15b that controls the turning on and off of each of the second light sources. The first control unit 15a controls the first light source to be lit at a higher intensity than a predetermined intensity when displaying a virtual image VI using the first display light L1, and the second control unit 15b controls the area of ​​the light source to be lit at a higher intensity than a predetermined intensity when displaying a real image RI using the second display light L2 to be larger than the area of ​​the light source to be lit at a higher intensity than the predetermined intensity when displaying a virtual image VI.

[0087] According to a second embodiment of the present invention, the HUD device 10B includes a backlight 11 having two systems, a light source 14, a display 12, and a control unit 15, each of which is for generating a virtual image VI and a real image RI, and which share an imaging optical system 13. The HUD device 1B is configured such that a first control unit 15a controls the first light source to be illuminated at a higher intensity than a predetermined intensity when a virtual image VI is displayed using a first display light L1, and a second control unit 15b controls the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when a real image RI is displayed using a second display light L2, so that the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when a virtual image VI is displayed is larger than the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when a virtual image VI is displayed. This configuration controls the outer edge of the light source area to be illuminated when a real image RI is displayed, for example, and the outer edge of the light source area that is not visible as the virtual image VI to be turned off when a virtual image VI is displayed, thereby reducing waste and improving light utilization efficiency while eliminating the difference in brightness between when a real image RI is displayed and when a virtual image VI is displayed. In this way, when one of the real image RI and the virtual image VI is displayed, the light emitted from the pixel in the direction for displaying the other is prevented from being wasted, thereby improving the light utilization efficiency.

[0088] Furthermore, as shown in FIG. 12, a control method for a head-up display device according to a second embodiment of the present invention is, for example, a HUD device 1B having an emission port 17 and emitting display light L from the emission port 17 toward a light-projecting member (windshield WS) to allow a virtual image VI and a real image RI of a display image represented by the display light L to be visually recognized, the HUD device 1B including a first backlight 11a having a plurality of first light sources mounted thereon, a first display 12a that generates first display light L1 by transmitting illumination light from the first light sources, a second backlight 11b having a plurality of second light sources mounted thereon, and a second display 12a that generates first display light L2 by transmitting illumination light from the first light sources. a second display 12b that transmits illumination light from the first light source 12a to generate second display light L2; an imaging optical system 13 that forms a virtual image VI by emitting the first display light L1 from an outlet 17 along a first optical path having a first optical path length, and forms a real image RI by emitting the second display light L2 from the outlet 17 along a second optical path having a second optical path length longer than the first optical path length; a first control unit 15a that controls the turning on and off of each of the first light sources; and a second control unit 15b that controls the turning on and off of each of the second light sources. The control method includes a step in which the first control unit 15a controls the first light source to be lit at a higher intensity than a predetermined intensity when a virtual image RI is displayed using the first display light L1, and a step in which the second control unit 15b controls the area of ​​the light source to be lit at a higher intensity than the predetermined intensity when a real image RI is displayed using the second display light L2 so that it is larger than the area of ​​the light source to be lit at a higher intensity than the predetermined intensity when a virtual image RI is displayed.

[0089] According to a control method for an HUD device 1B of a second embodiment of the present invention, the HUD device 1B includes a backlight 11, a light source 14, a display 12, and a control unit 15, each of which has two systems, one for generating a virtual image VI and one for generating a real image RI, and which shares an imaging optical system 13. The first control unit 15a controls the first light source to be illuminated at a higher intensity than a predetermined intensity when displaying a virtual image VI using a first display light L1, and the second control unit 15b controls the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when displaying a real image RI using a second display light L2, so that the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when displaying a virtual image VI is larger than the area of ​​the light source illuminated at a higher intensity than the predetermined intensity when displaying a virtual image VI. This control turns on, for example, the outer edge of the light source area when displaying a real image RI, and turns off the outer edge of the light source area that is not visible as the virtual image VI when displaying a virtual image VI, thereby reducing waste and improving light utilization efficiency while eliminating the difference in brightness between when displaying a real image RI and when displaying a virtual image VI. In this way, when one of a real image and a virtual image is being displayed, the light emitted from the pixel in the direction for displaying the other image is prevented from being wasted, thereby improving the light utilization efficiency.

[0090] In this embodiment, the windshield WS is used as the light-transmitting member, but a flat glass or a combiner may also be used.

[0091] The present invention is not limited to the above-described exemplary embodiments, and those skilled in the art will be able to easily modify the above-described exemplary embodiments to the extent that they fall within the scope of the claims. [Explanation of symbols]

[0092] REFERENCE SIGNS LIST 1 (1A, 1B) Head-up display device (HUD device), 10 Image generation unit (PGU), 10a First image generation unit (PGU-1), 10b Second image generation unit (PGU-2), 11 Backlight, 11a First backlight, 11b Second backlight, 12 Display, 12a First display, 11b Second display, 13 Imaging optical system, 14 Light source, 15 Control unit, 15a First control unit, 13 b... second control section, 17... emission port, 20... switch, 30... various devices, 131... first mirror, 132... second mirror, 133... third mirror, 121... display element, 122... polarization control element, 151... display control section, 152... display drive section, 153... light source drive section, 140... light source circuit board, 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, and emitting display light from the emission port toward a light-projecting member to allow a virtual image and a real image of a display image represented by the display light to be visually recognized, A backlight having multiple light sources implemented therein; a display that generates display light by transmitting illumination light emitted by the light source; a polarization control element for switching the polarization state of the display light; an imaging optical system that forms the virtual image by emitting first display light in a first polarization state from the exit along a first optical path having a first optical path length, and forms the real image by emitting second display light in a second polarization state from the exit along a second optical path having a second optical path length longer than the first optical path length; a control unit that controls the polarization state of the display light by the polarization control element and the turning on and off of each of the light sources, The control unit A head-up display device that controls the area of ​​the light source that is lit with a stronger intensity than a predetermined intensity when displaying the real image to be larger than the area of ​​the light source that is lit with a stronger intensity than the predetermined intensity when displaying the virtual image.

2. The control unit 2. The head-up display device according to claim 1, wherein when switching the display from the virtual image to the real image, the head-up display device controls a light source arranged in an implementation area that does not overlap with the display when viewed from a normal direction of the light source circuit board of the backlight on which the light source is mounted to light up more brightly than the predetermined intensity.

3. The control unit 2. The head-up display device according to claim 1, wherein the area of ​​the light source mounted on the light source circuit board of the backlight that is lit with a stronger intensity than a predetermined intensity when the real image is displayed is controlled to be larger along the long side direction of the rectangular area of ​​the display than the area of ​​the light source mounted on the light source circuit board that is lit with a stronger intensity than the predetermined intensity when the virtual image is displayed.

4. The control unit 2. The head-up display device according to claim 1, wherein the area of ​​the light source mounted on the light source circuit board of the backlight that is lit with a stronger intensity than a predetermined intensity when the real image is displayed is controlled to be larger along each of the long side direction and the short side direction of the rectangular area of ​​the display than the area of ​​the light source mounted on the light source circuit board that is lit with a stronger intensity than a predetermined intensity when the virtual image is displayed.

5. The control unit 2. The head-up display device according to claim 1, wherein the area of ​​the light source mounted on the light source circuit board of the backlight that is lit with a stronger intensity than a predetermined intensity when the real image is displayed is controlled to be larger along each of the long side direction and the short side direction of the rectangular area of ​​the display than the area of ​​the light source mounted on the light source circuit board that is lit with a stronger intensity than a predetermined intensity when the virtual image is displayed, and the area of ​​the light source that is increased is controlled to be larger in the long side direction than in the short side direction.

6. A head-up display device having an emission port, and emitting display light from the emission port toward a light-projecting member to allow a virtual image and a real image of a display image represented by the display light to be visually recognized, a first backlight having a plurality of first light sources mounted thereon; a first display that transmits illumination light from the first light source to generate first display light; a second backlight having a plurality of second light sources mounted thereon; a second display that transmits illumination light from the second light source to generate second display light; an imaging optical system that forms the virtual image by emitting the first display light from the exit along a first optical path having a first optical path length, and forms the real image by emitting the second display light from the exit along a second optical path having a second optical path length longer than the first optical path length; a first control unit that controls turning on and off each of the first light sources; a second control unit that controls turning on and off each of the second light sources; The first control unit When the virtual image is displayed by the first display light, the first light source is controlled to be illuminated with intensity stronger than a predetermined intensity; The second control unit A head-up display device that controls the area of ​​the light source that is lit stronger than a predetermined intensity when displaying the real image using the second display light to be larger than the area of ​​the light source that is lit stronger than the predetermined intensity when displaying the virtual image.

7. a control method for a head-up display device including: a backlight having a light source mounting substrate on which a plurality of light sources are mounted; a display that generates display light by transmitting illumination light from the light sources of the backlight; a polarization switching element that switches a polarization state of the display light; an imaging optical system that forms the virtual image by emitting first display light in a first polarization state from the emission outlet along a first optical path having a first optical path length, and forms the real image by emitting second display light in a second polarization state from the emission outlet along a second optical path having a second optical path length longer than the first optical path length; and a control unit that controls the polarization state of the display light by the polarization control element and controls turning on and off each of the plurality of light sources of the backlight, The control unit switching the imaging optical system from the first optical path to the second optical path to switch the display from the virtual image to the real image; The control unit performing control so that an area of ​​a light source region of the light source mounted on the light source circuit board that is turned on with more intensity than a predetermined intensity when the real image is displayed is larger than an area of ​​a light source region of the light source that is turned on with more intensity than the predetermined intensity when the virtual image is displayed; A control method for a head-up display device having the following.

8. a first backlight having a plurality of first light sources mounted thereon; a first display that generates first display light by transmitting illumination light from the first light source; a second backlight having a plurality of second light sources mounted thereon; a second display that generates second display light by transmitting illumination light from the second light source; an imaging optical system that forms the virtual image by emitting the first display light from the emission outlet along a first optical path having a first optical path length, and forms the real image by emitting the second display light from the emission outlet along a second optical path having a second optical path length longer than the first optical path length; a first control unit that controls turning on and off each of the first light sources; and a second control unit that controls turning on and off each of the second light sources, The first control unit a step of controlling the first light source to be lit with intensity stronger than a predetermined intensity when the virtual image is displayed by the first display light; The second control unit performing control so that an area of ​​the light source that is lit with more intensity than a predetermined intensity when the real image is displayed by the second display light is larger than an area of ​​the light source that is lit with more intensity than the predetermined intensity when the virtual image is displayed; A control method for a head-up display device having the following.

Images