Head-up display device

Abstract

To provide a head-up display device capable of instantaneously switching between real and virtual images for use depending on the driving situation.SOLUTION: A head-up display is provided, comprising a display unit 12 capable of switching polarization of emitted light between first polarization and second polarization, a first mirror 131 configured to reflect display light L1 of the first polarization and transmit display light L2 of the second polarization, a second mirror 132 for reflecting the display light L2, and a control unit 15 for controlling the display unit 12. The head-up display is configured such that either of the first mirror 131 or the second mirror 132 has an upper-side curvature radius that is different from a lower-side curvature radius to make a first angle for displaying a virtual image VI roughly the same as a second angle for displaying a real image RI.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a head-up display device that displays a desired image to a viewer by switching between a virtual image and a real image. [Background technology]

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

[0003] [Patent Document 1] JP 2011-70074 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the technology described in Patent Document 1, when an observer switches between a virtual image and a real image, the relative positions of the object to be observed, the dihedral corner reflector array, and the reflecting member must be mechanically changed, which makes it difficult to smoothly switch between virtual and real images and results in an increase in the size of the device, making it difficult to mount.

[0005] Therefore, the present invention has been made in consideration of the above problems, and aims to provide a head-up display device that can instantly switch between a real image and a virtual image depending on the driving situation. [Means for solving the problem]

[0006] The present invention provides a head-up display device 1 having an outlet 17, and emitting display light L from the outlet 17 toward a light-transmitting member 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 head-up display device 1 includes a display element 121, and a switching element 122 that is provided closer to the outlet 17 along an optical path than the display element 121 and is capable of switching the polarization of emitted light between a first polarization and a second polarization that are different from each other. The head-up display device 1 includes a display element 121, and a switching element 122 that is provided on the outlet 17 side along an optical path from the display element 121 and is capable of switching the polarization of emitted light between a first polarization and a second polarization that are different from each other. The head-up display device 1 includes a display unit 12 that transmits light emitted by a light source 11 and displays the display image, a reflecting unit 13 that reflects light representing the display image displayed on the display unit 12 toward the light-transmitting member WS, and a control unit 15 that controls the switching element 122. The reflecting unit 13 includes a first mirror 131 that reflects a first light ray L1 having the first polarization and transmits a second light ray L2 having the second polarization, and a second mirror 132 that reflects the second light ray L2. The first mirror 131 and the second mirror 132 are arranged such that, when the display element 121 emits the first light ray L1, the positional relationship between the optical focus F of the imaging optical system including the translucent member WS and the reflecting portion 13 and the display unit 12 is a first state in which the display unit 12 is closer to the exit 17 than the optical focus F, and when the display element 121 emits the second light ray L2, the positional relationship between the display unit 12 is a second state in which the display unit 12 is closer to the light source 11 than the optical focus F.The first mirror 131 and the second mirror 132 are arranged such that, by having upper radii of curvature (R1U, R2U) and lower radii of curvature (R1L, R2L) of the first mirror 131 and the second mirror 132 different from each other, the first angle of the virtual image VI viewed in the first state with respect to the road surface and the second angle of the real image RI viewed in the second state with respect to the road surface are approximately identical to each other.

[0007] The display unit is also characterized in that it is disposed at an angle to the axial direction of the optical path. Effect of the Invention

[0008] According to the present invention, by making the radius of curvature on the upper side and the radius of curvature on the lower side of at least one of the first mirror and the second mirror different from each other, it is possible to smoothly switch between displaying a virtual image that is inclined with respect to the road surface and a real image that is perpendicular to the road surface on a single display unit without changing the tilt angle.

[0009] Furthermore, according to the present invention, stray light and external light can be excluded from the optical path. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a configuration for generating a virtual image in a head-up display device according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram showing a configuration for generating a real image in a head-up display device according to a first embodiment of the present invention. [Diagram 3] 1 is a schematic diagram showing the structure of a light source and a display unit in a head-up display device according to a first embodiment of the present invention. [Figure 4] FIG. 2 is a functional block diagram showing the configuration of an image generating unit in the head-up display device according to the first embodiment of the present invention. [Diagram 5] 6A is a first cross-sectional view showing a structure of a first mirror, and FIG. 6B is a first cross-sectional view showing a structure of a second mirror of a head-up display device according to a second embodiment of the present invention. [Figure 6] 6A is a second cross-sectional view showing the structure of a first mirror and FIG. 6B is a second cross-sectional view showing the structure of a second mirror of a head-up display device according to a second embodiment of the present invention. [Figure 7] 7 is a diagram showing a configuration in which a virtual image is generated using the first mirror and the second mirror shown in FIG. 6 in a head-up display device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (First embodiment of the present invention) Hereinafter, a first embodiment of the present invention will be described 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, referred to as a HUD device) according to this embodiment, and Fig. 2 is a diagram showing a configuration in which a real image is generated in the HUD device according to this embodiment.

[0012] 1 and 2, the HUD device 1 includes a light source 11 that is composed of a light-emitting diode that emits light in the visible wavelength range mounted on a wiring board and emits white light, a display unit 12 that generates an image using light incident from the light source 11 and switches the polarization of the emitted light between first and second polarized light that are different from each other, a reflecting unit 13 that reflects display light L (display light L1 that represents a display image of a virtual image VI in the case of FIG. 1, and 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 unit 12 toward a windshield WS (translucent member), and a control unit 15 that controls the display content on the display unit 12 and controls switching between the first and second polarized light, and these are housed in a housing 16. The housing 16 is provided with an opening 17 (exit) through which the display light L is emitted, and a cover glass 18 for protecting the inside is disposed in the opening 17. The windshield WS is an example of a light-projecting member, and the opening 17 is an example of an exit.

[0013] The HUD device 1 is disposed below the windshield WS of the vehicle C (for example, inside the instrument panel), and emits display light L (L1, L2) and projects it onto the windshield WS. The display light L is generated by a light source 11 and a display unit 12 inside the HUD device 1. The display light L emitted from the display unit 12 travels along a reflecting unit 13 and is emitted through an opening 17 of a housing 16 and 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 back side of the windshield WS as shown in FIG. 1 and a real image RI on the front side as shown in FIG. 2.

[0014] In the virtual image VI shown in FIG. 1, information that is highly necessary to draw the attention of the occupant DR, such as vehicle information such as the speed and engine RPM of the vehicle C, route guidance displays such as turn-by-turn and maps, blind spot indicators, warning displays such as speed limit exceeding warnings, etc., are displayed on the other side of the windshield WS as viewed from the occupant DR. In addition, in the real image RI shown in FIG. 2, for example, entertainment content, assistants and agents that support the occupant DR, and characters representing them are displayed on the front side of the windshield WS as viewed from the occupant DR. These displays provide a driving environment in which the need for viewpoint movement and eye focal length adjustment is reduced. The virtual image VI and real image RI include characters and icons indicating these information as well as background parts, which are, for example, approximately rectangular in shape when viewed in a planar view from the occupant DR.

[0015] Here, the configurations of the light source 11 and the display unit 12 will be described. Fig. 3 is a schematic diagram showing the structures of the light source 11 and the display unit 12 in the HUD device 1 according to this embodiment. As shown in Fig. 3, the display unit 12 is provided closer to the emission port along the optical path than the light source 11. The display unit 12 includes, for example, a TFT (Thin Film Transistor) type display element 121, and a switching element 122 that is provided closer to the emission port along the optical path than the display element 121 and switches the polarization of the emitted display light L between first polarization and second polarization that are different from each other.

[0016] For example, the first polarized light may be S polarized light and the second polarized light may be P polarized light, or vice versa. In addition, it is not limited to S polarized light or P polarized light, as long as the polarization angles of the first polarized light and the second polarized light are different, and it is preferable that the polarization angles differ by at least 22.5 degrees, for example.

[0017] In addition, as shown in Figures 1 and 2, it is desirable to arrange the display unit 12 at an angle with respect to the axis (optical axis) of the light ray of the display light L in order to exclude stray light (light leaking from the light source 11) and external light (light entering from outside) from the optical path of the display light L.

[0018] The display element 121 is connected to the display control unit 21, which will be described later in FIG. 4, and forms light that displays a figure of any shape according to a signal sent from the display control unit 21. The switching element 122 extracts only light of a specific polarization, specifically, the above-mentioned first polarization or second polarization, from the light beam emitted from the display element 121, and switches between them. The switching element 122 is connected to the display unit drive unit 22, which will be described later in FIG. 4, and switches the polarization according to a signal sent from the display unit drive unit 22.

[0019] The switching of polarization by the switching element 122 may be performed by electrical processing, or the polarization may be switched by arranging a polarizing plate or a wavelength plate on the exit side of the display element 121 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 unit drive unit 22.

[0020] The reflecting unit 13 includes a first mirror 131, a second mirror 132, and a third mirror 133, each of which is a mirror having a concave shape. The first mirror 131 reflects the display light L1 (first light ray) having the first polarization and transmits the display light L2 (second light ray) having the second polarization. The second mirror 132 is a mirror that reflects the display light L2 (second light ray) that transmits the first mirror 131. The display lights L1 and L2 reflected by the first mirror 131 and the second mirror 132 are guided to the third mirror 133, reflected by the third mirror 133, and emitted to the windshield WS, so that the occupant DR can view the respective display images. The display light L1 is an example of a first light ray, and the display light L2 is an example of a second light ray.

[0021] In reality, there are countless light rays emitted from the display unit 12, but for ease of explanation, the light emitted from the center of the display unit 12 and passing through the center of the eye box is referred to as a representative light ray and is indicated by the symbol L. In addition, in Figures 1 and 2, as well as Figure 7 described below, the representative light ray emitted from the center of the display unit 12 is indicated by a solid line, the light ray emitted from the upper end of the display unit 12 is indicated by a dashed line, and the light ray emitted from the lower end of the display unit 12 is indicated by a dashed line.

[0022] 2, since the first mirror 131 is a mirror that transmits the display light L2, it is naturally possible for the display light L2 reflected by the second mirror 132 to be transmitted from the rear side where the second mirror 132 is located to the front side. That is, as shown in FIG. 2, the display light L2 transmitted through the first mirror 131 is reflected by the second mirror 132, transmitted through the first mirror 131 again, and guided to the third mirror 133. This makes it possible to arrange the second mirror 132 close to the rear side of the first mirror 131, and prevents the housing 16 from becoming large.

[0023] Here, for example, the first polarized light is S polarized light (S polarized light relative to the first mirror 131), the second polarized light is P polarized light (P polarized light relative to the first mirror 131), the first mirror 131 is a mirror that reflects S polarized light toward the first mirror 131 and transmits P polarized light, and the second mirror 132 is a mirror that reflects P polarized light toward the first mirror 131 and transmits S polarized light. In this configuration, the display light L1, which is S polarized light, is reflected by the first mirror 131 and guided to the third mirror 133. The display light L2, which is P polarized light, 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 reflecting unit 13 and the polarizations of the display lights L1 and L2, it is possible for the display lights L1 and L2 to generate different display images.

[0024] A display image represented by the display light L1 in Fig. 1 and a display image represented by the display light L2 in Fig. 2 will be specifically described. As shown in Fig. 2, the second mirror 132 is a mirror having a concave shape, and has a radius of curvature such that, when the second mirror 132, the third mirror 133, and the windshield WS are regarded as one optical system, the position of the display unit 12 is in a second state outside the focal length of the optical system (on the front side with respect to the display light L). As a result, when light of the second polarization is emitted, the light reflected by the second mirror 132, the third mirror 133, and the windshield WS is visually recognized as a real image RI by the occupant DR.

[0025] As shown in FIG. 1, the first mirror 131 is also a mirror having a concave shape, but has a radius of curvature R1 (R1>R2) larger than the radius of curvature R2 of the second mirror 132, and has a radius of curvature such that, when the first mirror 131, the third mirror 133, and the windshield WS are regarded as one optical system, the position of the display unit 12 is in a first state inside the focal length of the optical system (on the rear side with respect to the display light L). This is because, when the radius of curvature of the mirror having a concave shape is large, the focal length becomes farther from the mirror, and when the radius of curvature is small, the focal length becomes closer to the mirror, so that the radius of curvature of the first mirror 131, which makes the focal length farther, is larger. As a result, when the first polarized light is emitted, the light reflected by the first mirror 131, the third mirror 133, and the windshield WS is visually recognized by the occupant DR as a virtual image VI. Note that the optical focus is indicated by F in FIG. 1 and FIG. 2.

[0026] That is, for example, when it is desired that a virtual image VI be viewed on the rear side of the windshield WS as seen from the occupant DR, the switching element 122 of the display unit 12 switches the display light L to be emitted as display light L1, which is a first polarization, and the display image represented by the display light L1 is displayed on the windshield WS by the imaging optical system composed of the first mirror 131, the third mirror 133, and the windshield WS. Also, for example, when it is desired that a real image RI be viewed on the front side of the windshield WS as seen from the occupant DR, the switching element 122 of the display unit 12 switches the display light L to be emitted as display light L2, which is a second polarization, and the display image represented by the display light L2 is displayed on the windshield WS by the imaging optical system composed of the second mirror 132, the third mirror 133, and the windshield WS.

[0027] In addition, in Figures 1 and 2, the first mirror 131 is described as a mirror having a concave shape, but as long as the condition that the position of the display unit 12 is inside the focal length of the optical system (the rear side with respect to the display light L) when the first mirror 131, the third mirror 133 and the windshield WS are considered as a single optical system is satisfied, the first mirror 131 may be a mirror having a flat shape or a mirror having a convex shape.

[0028] By adopting such a shape and arrangement of the first mirror 131 and the second mirror 132, and further controlling the polarization of the display light L1 and the display light L2, it is possible to switch the display image viewed by the occupant DR between a virtual image VI and a real image RI.

[0029] In addition, in Figures 1 and 2, the third mirror 133 is described as a mirror having a concave shape, but it may also be a mirror having a flat shape or a mirror having a convex shape, and since the display lights L1, L2 are irradiated via the same third mirror 133 whether a virtual image VI or a real image RI is displayed, the third mirror 133 may have a shape without magnification.

[0030] Furthermore, when the third mirror 133 has a concave shape, it is desirable that the radius of curvature R3 is larger than the radius of curvature R1 of the first mirror 131 and the radius of curvature R2 of the second mirror 132 (R3>R1, R3>R2). The reason for this is that when the magnification of the third mirror 133 is high, the focal length of the entire optical system becomes closer to the third mirror 133, so that the virtual image VI is displayed large and far away from the occupant DR, and the real image RI is displayed small and far away from the occupant DR, which may reduce the visibility of the real image RI in particular, and by configuring the third mirror 133 as described above, such a reduction in visibility can be prevented.

[0031] FIG. 4 is a functional block diagram showing the configuration of an image generating unit (hereinafter, referred to as a Picture Generation Unit: PGU) in the HUD device 1 according to this embodiment. Note that FIG. 4 shows only the minimum necessary configuration directly related to the present invention, and other known configurations are omitted. In FIG. 4, the PGU 10 includes a control unit 15, a light source 11, and a display unit 12. The control unit 15 includes a display control unit 21 that issues an instruction to the display unit 12 to generate light representing a figure of an arbitrary shape based on information sent from various devices 30 such as a vehicle speed sensor, a navigation device, a RADAR (Radio Detecting and Ranging), a LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), and a display unit drive unit 22 that performs switching control of the polarization direction based on a signal sent from a switch 20 that switches between driving modes (manual driving, automatic driving), for example.

[0032] The display unit 12 also includes a TFT-type display element 121 that forms light representing a figure of any shape in accordance with a signal sent from the display control unit 21, and a switching element 122 that switches the emitted display light L to either the first polarized display light L1 or the second polarized display light L2 in accordance with a signal sent from the display unit drive unit 22.

[0033] In the configuration of Fig. 4, for example, during manual driving, the display unit drive unit 22 controls the switching element 122 to emit display light L1 of the first polarization. At this time, the display control unit 21 controls the display element 121 to generate display light L1 that represents vehicle information, route guidance information, warning displays, and the like as described above. Also, for example, during autonomous driving, the display unit drive unit 22 controls the switching element 122 to emit display light L2 of the second polarization. At this time, the display control unit 21 controls the display element 121 to generate display light L2 that represents an assistant or agent that supports the occupant DR as described above, or a character that represents them.

[0034] In this way, in the HUD device 1 according to the present embodiment, when a virtual image VI is to be displayed, the display unit 12 that controls polarization changes the polarization state of the light source 11 to a polarization state that is reflected by the first mirror 131, so that the display light L1 is reflected by the first mirror 131, enters the third mirror 133, is reflected by the third mirror 133, enters the windshield WS, is reflected by the windshield WS, and becomes a virtual image VI that can be displayed at a distance. When a real image RI is to be displayed, the display unit 12 that controls polarization changes the polarization state of the light source 11 to a polarization state that is transmitted by the first mirror 131, so that the display light L2 is transmitted by the first mirror 131, is reflected by the second mirror 132, is transmitted again by the first mirror 131, enters the third mirror 133, is reflected by the third mirror 133, enters the windshield WS, and is reflected by the windshield WS to become a real image RI. At this time, the second mirror 132 has a concave shape, and the real image RI is generated by making the focal length of the mirror optical system shorter than the distance between the display unit 12 and the mirror optical system. In other words, by switching the polarization state of the display light L emitted from the display unit 12 without mechanically moving the display unit 12, it becomes possible to change the distance (optical path length) between the display unit 12 and the mirror, and smoothly switch between the virtual image VI and the real image RI.

[0035] Furthermore, when the first mirror 131 and the second mirror 132 have curved shapes, the radius of curvature R1 of the first mirror 131 is larger than the radius of curvature R2 of the second mirror 132, so that in the optical path of the display light L1 that displays the virtual image VI, the focal length of the first mirror 131 is longer than the distance between the display unit 12 and the first mirror 131, making it possible to generate the virtual image VI, and in the optical path of the display light L2 that displays the real image RI, the focal length of the second mirror 132 is shorter than the distance between the display unit 12 and the second mirror 132, making it possible to generate the real image RI.

[0036] Furthermore, if the magnification of the third mirror 133 is too high, the focal length of the entire optical system will be closer to the mirror, and the virtual image VI will be larger and displayed farther away, while the real image RI will be smaller and displayed farther away from the occupant DR, which may reduce visibility. However, by making the radius of curvature R3 of the third mirror 133 larger than the radius of curvature R1 of the first mirror 131 and the radius of curvature R2 of the second mirror 132, as in this embodiment, the above problem can be avoided.

[0037] (Second embodiment of the present invention) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Descriptions of this embodiment that overlap with those of the first embodiment will be omitted.

[0038] Like the HUD device 1 according to the first embodiment, when switching between the virtual image VI and the real image RI depending on the situation, there are cases where it is desired to display the display area of ​​the virtual image VI in a distant location in an inclined state with respect to the road surface (for example, a lying state with an angle of less than 45° with the road surface) and the display area of ​​the real image RI in a nearby location in an upright state with respect to the road surface (for example, an angle of 45° or more with the road surface, more specifically, a vertical state). For example, the display area of ​​the virtual image VI with an angle of less than 45° with the road surface looks like the display contents are developed on the road surface, so that when performing navigation, the display contents look superimposed on the road surface, which is advantageous in that intuitive information presentation is possible. On the other hand, the display area of ​​the real image RI in a nearby location with an angle of 45° or more with the road surface is expected to be used in situations where entertainment content is viewed during automatic driving or while the vehicle is stopped, and has the advantage of improving visibility by being displayed in an upright state with respect to the road surface.

[0039] As shown in FIG. 1 and FIG. 2 in the first embodiment, the display unit 12 is disposed at an incline with respect to the axial direction of the light ray of the display light L in order to eliminate stray light and external light from the optical path of the display light L. Here, the display unit 12 is disposed at an incline of approximately 45 degrees with respect to the optical axis. At this time, by inclining the upper side of the display unit 12 in the optical axis direction so that it faces the first mirror 131, the virtual image VI can be displayed as if it is inclined with respect to the road surface. As described above, this allows intuitive information presentation in which the virtual image VI is developed on the road surface, but it also affects the inclination angle of the real image RI with respect to the road surface, and the real image RI cannot be displayed as if it is standing vertically with respect to the road surface. This problem can be solved by mechanically changing the tilt angle of the display unit 12 in response to switching between the display of the virtual image VI and the real image RI, but in this embodiment, the virtual image VI displayed in the distance is displayed at an incline with respect to the road surface, and the real image RI displayed in the near distance is displayed as if it is standing vertically with respect to the road surface, without mechanically changing the tilt angle of the display unit 12.

[0040] 5 is a first cross-sectional view showing the structure of the first mirror 131 and the second mirror 132 of the HUD device 1 according to this embodiment. FIG. 5(A) is a cross-sectional view of the first mirror 131 when viewed from the side, and FIG. 5(B) is a cross-sectional view of the second mirror 132 when viewed from the side. As shown in FIG. 5(A), the radius of curvature R1U of the upper side of the first mirror 131 is formed larger than the radius of curvature R1L of the lower side (R1U>R1L). As shown in FIG. 5(B), the radius of curvature R2U of the upper side of the second mirror 132 is also formed larger than the radius of curvature R2L of the lower side (R2U>R2L).

[0041] In the configuration shown in Fig. 1, when a virtual image VI is displayed, the lower side of the display image (corresponding to the upper side of the display unit 12) is an image formed by the display light L1 reflected by a portion (R1U) of the first mirror 131 with a large radius of curvature, so the projection distance is on the near side as viewed from the occupant DR. On the other hand, the upper side of the display image (corresponding to the lower side of the display unit 12) is an image formed by the display light L1 reflected by a portion (R1L) of the first mirror 131 with a small radius of curvature, so the projection distance is on the far side as viewed from the occupant DR. That is, by making the first mirror 131 have the structure shown in Fig. 5(A), the inclination of the virtual image VI with respect to the optical axis can be made larger than the inclination of the display unit 12 with respect to the optical axis, so that the virtual image VI is displayed with an inclination of less than 45° (first angle) with respect to the road surface.

[0042] In addition, in the configuration shown in FIG. 2, when the real image RI is displayed, the lower side of the display image (corresponding to the lower side of the display unit 12: the position of the optical focus F is different from that in FIG. 1, so the top, bottom, left and right of the image are inverted and the image is the opposite to that in FIG. 1) is an image formed by the display light L2 reflected by the part (R2U) of the second mirror 132 with a large radius of curvature, so the projection distance is on the far side as seen from the occupant DR. On the other hand, the upper side of the display image (corresponding to the upper side of the display unit 12: for the same reason as above) is an image formed by the display light L2 reflected by the part (R2L) of the second mirror 132 with a small radius of curvature, so the projection distance is on the near side as seen from the occupant DR. That is, by making the second mirror 132 have the structure shown in FIG. 5(B), the inclination of the real image RI with respect to the optical axis can be made smaller than the inclination of the display unit 12 with respect to the optical axis, so that the real image RI is displayed at 45° or more (second angle) with respect to the road surface (here, particularly, as if it is standing vertically).

[0043] In addition, there may be cases where it is desired to display the display area of ​​a distant virtual image VI perpendicular to the road surface, and to display the display area of ​​a nearby real image RI perpendicular to the road surface as well. This can be achieved by configuring the first mirror 131 and the second mirror 132 as shown in FIG.

[0044] FIG. 6 is a second cross-sectional view showing the structure of the first mirror 131 and the second mirror 132 of the HUD device 1 of this embodiment, and FIG. 7 is a diagram showing the configuration when a virtual image VI is generated using the first mirror 131 and the second mirror 132 shown in FIG. 6 in the HUD device 1 of this embodiment.

[0045] FIG. 6(A) is a cross-sectional view of the first mirror 131 as viewed from the side, and FIG. 6(B) is a cross-sectional view of the second mirror 132 as viewed from the side. In FIG. 6(A), the upper radius of curvature R1U of the first mirror 131 is formed smaller than the lower radius of curvature R1L (R1U < R1L). That is, as shown in FIG. 7, when displaying the virtual image VI, the lower side of the displayed image (corresponding to the upper side of the display unit 12) is an image formed by the display light L1 reflected by the portion (R1U) with a smaller radius of curvature of the first mirror 131, so the projection distance is on the back side as viewed from the occupant DR. On the other hand, the upper side of the displayed image (corresponding to the lower side of the display unit 12) is an image formed by the display light L1 reflected by the portion (R1L) with a larger radius of curvature of the first mirror 131, so the projection distance is on the front side as viewed from the occupant DR. That is, by configuring the first mirror 131 as shown in FIG. 6(A), the virtual image VI is displayed at an angle of 45° or more (the first angle) with respect to the road surface (here, particularly as if standing vertically).

[0046] Also, in FIG. 6(B), similar to the case of FIG. 5(B), the upper radius of curvature R2U of the second mirror 132 is formed larger than the lower radius of curvature R2L (R2U > R2L). As a result, as shown in FIG. 2, the lower side of the displayed image is an image formed by the display light L2 reflected by the portion (R2U) with a larger radius of curvature of the second mirror 132, so the projection distance is on the back side as viewed from the occupant DR, and the upper side of the displayed image is an image formed by the display light L2 reflected by the portion (R2L) with a smaller radius of curvature of the second mirror 132, so the projection distance is on the front side as viewed from the occupant DR. That is, the inclination angle is substantially the same as that of the virtual image VI shown in FIG. 7, and the real image RI is displayed at an angle of 45° or more (the second angle) with respect to the road surface (here, particularly as if standing vertically).

[0047] By configuring the first mirror 131 and the second mirror 132 as shown in FIG. 6, it becomes possible to display both the virtual image VI displayed in the distance and the real image RI displayed nearby as if they are both standing vertically with respect to the road surface.

[0048] In this way, in the HUD device 1 of this embodiment, the radius of curvature R1U of the upper side of the first mirror 131 is larger than the radius of curvature R1L of the lower side, and the radius of curvature R2U of the upper side of the second mirror 132 is larger than the radius of curvature R2L of the lower side, so that a virtual image VI that is inclined with respect to the road surface and a real image RI that is perpendicular to the road surface can be displayed on a single display unit 12 without changing the tilt angle.

[0049] Furthermore, by making the radius of curvature R1U of the upper side of the first mirror 131 smaller than the radius of curvature R1L of the lower side and making the radius of curvature R2U of the upper side of the second mirror 132 larger than the radius of curvature R2L of the lower side, it is possible to display a virtual image VI and a real image RI perpendicular to the road surface on a single display unit 12 without changing the tilt angle.

[0050] Furthermore, by arranging the display unit 12 at an angle with respect to the axial direction of the light beam of the display light L, stray light and external light can be excluded from the optical path of the display light L, thereby improving the display quality.

[0051] In each embodiment, the display unit 12 is inclined with respect to the axial direction of the display light L, but it may be arranged perpendicular to the axial direction of the light without being inclined. That is, when it is desired to increase the inclination angle of the virtual image VI with respect to the road surface, the display unit 12 is inclined so that the upper side of the display unit 12 faces the first mirror 131 as shown in Fig. 1 and Fig. 5, and when it is not necessary to increase the inclination angle of the virtual image VI with respect to the road surface so much, the display unit 12 may be arranged perpendicular to the axial direction of the light.

[0052] Further, regarding the radii of curvature of the first mirror 131 and the second mirror 132, for at least one of the first mirror 131 or the second mirror 132, a configuration in which the upper radius of curvature and the lower radius of curvature are made different may be adopted so that the tilt angle (first angle) of the virtual image VI and the tilt angle (second angle) of the real image RI are made different from each other. That is, any combination that gives the desired tilt of the displayed image may be arbitrarily selected from the eight combinations of (1) R1U > R1L, (2) R1U < R1L, (3) R2U > R2L, (4) R2U < R2L, (5) R1U > R1L and R2U > R2L, (6) R1U > R1L and R2U < R2L, (7) R1U < R1L and R2U > R2L, (8) R1U < R1L and R2U < R2L. At this time, the display unit 12 may be arranged to be tilted with respect to the axial direction of the light beam of the display light L (for example, tilted so that the upper side of the display unit 12 faces the first mirror 131 side), or may be arranged to be orthogonal to the axial direction of the light beam of the display light L.

[0053] Furthermore, regarding the radii of curvature of the first mirror 131 and the second mirror 132, for at least one of the first mirror 131 or the second mirror 132, a configuration in which the upper radius of curvature and the lower radius of curvature are made different may be adopted so that the tilt angle (first angle) of the virtual image VI and the tilt angle (second angle) of the real image RI are made substantially the same. That is, any combination that gives the desired tilt of the displayed image may be arbitrarily selected from the eight combinations of (1) R1U > R1L, (2) R1U < R1L, (3) R2U > R2L, (4) R2U < R2L, (5) R1U > R1L and R2U > R2L, (6) R1U > R1L and R2U < R2L, (7) R1U < R1L and R2U > R2L, (8) R1U < R1L and R2U < R2L. At this time, the display unit 12 may be arranged to be tilted with respect to the axial direction of the light beam of the display light L (for example, tilted so that the upper side of the display unit 12 faces the first mirror 131 side), or may be arranged to be orthogonal to the axial direction of the light beam of the display light L.

[0054] Regarding the combination method of the radii of curvature of the first mirror 131 and the second mirror 132, and the tilt angle of the display unit 12, several specific examples other than the configurations shown in FIGS. 5 to 7 are shown below. As a first example, the display unit 12 is arranged to be tilted so that the upper side is on the side of the first mirror 131, and only for the second mirror 132, the structure is such that the radius of curvature of the upper side is larger than the radius of curvature of the lower side (the structure of FIG. 5(B)). The virtual image VI may be displayed while being tilted at less than 45° (first angle) with respect to the road surface, and the real image RI may be displayed in an upright state at 45° or more (second angle) with respect to the road surface. Thereby, while the virtual image VI is surely displayed in a tilted state, the real image RI can be surely displayed in an upright state.

[0055] As a second example, the display unit 12 is arranged to be tilted so that the upper side is on the side of the first mirror 131. For both the first mirror 131 and the second mirror 132, by making the structure such that the radius of curvature of the upper side is smaller than the radius of curvature of the lower side (R1U < R1L, R2U < R2L), the virtual image VI can be displayed at 90° or more (first angle) with respect to the road surface (for example, in a state of standing slightly bent forward as seen from the occupant DR), and the real image RI can be displayed at 45° or more (second angle) with respect to the road surface (for example, in a state of being tilted slightly rearward as seen from the occupant DR).

[0056] As a third example, the display unit 12 is arranged perpendicular to the axial direction of the light rays of the display light L. For only the first mirror 131, the structure is such that the radius of curvature of the upper side is larger than the radius of curvature of the lower side (the structure of FIG. 5(A)). The virtual image VI may be displayed while being tilted at less than 45° (first angle) with respect to the road surface, and the real image RI may be displayed in an upright state at 45° or more (second angle) with respect to the road surface. Thereby, while the virtual image VI is surely displayed in a tilted state, the real image RI can be surely displayed in an upright state.

[0057] As a fourth example, the display unit 12 is arranged orthogonally to the axial direction of the light beam of the display light L. For the first mirror 131, it has a structure in which the upper radius of curvature is larger than the lower radius of curvature (the structure in FIG. 5(A)). For the second mirror 132, it has a structure in which the upper radius of curvature is smaller than the lower radius of curvature (R2U < R2L). The virtual image VI may be displayed while being inclined at less than 45° (first angle) with respect to the road surface, and the real image RI may also be displayed while being inclined at less than 45° (second angle) with respect to the road surface. Thereby, the virtual image VI and the real image RI can be surely displayed in an inclined state.

[0058] In the above description, the structure in which the upper radius of curvature and the lower radius of curvature of the first mirror 131 and the second mirror 132 are different has been described. However, it may be a structure in which the radius of curvature continuously changes from the upper end portion to the lower end portion of each mirror.

[0059] (Other Embodiments of the Present Invention) As other embodiments of the HUD device 1 according to the present embodiment, the following appendices are shown.

[0060] (Supplementary Note 1) A head-up display device 1 has an exit 17, and emits display light L from the exit 17 toward a light-transmitting member WS, thereby allowing a virtual image VI and a real image RI of a display image represented by the display light L to be visually recognized. The head-up display device 1 includes a display element 121, and a switching element 122 that is provided on the exit 17 side along an optical path from the display element 121 and is capable of switching the polarization of emitted light between a first polarization and a second polarization that are different from each other. The head-up display device 1 includes a display unit 12 that transmits light emitted by a light source 11 and displays the display image, a reflecting unit 13 that reflects light representing the display image displayed on the display unit 12 toward the light-transmitting member WS, and a control unit 15 that controls the switching element 122. The reflecting unit 13 reflects a first light ray L1 that is a first polarized light. a first mirror 131 that transmits a second light ray L2 that is emitted from the display element 121 and becomes a second polarized light, and a second mirror 132 that reflects the second light ray L2, wherein the first mirror 131 and the second mirror 132 are arranged such that, when the display element 121 emits the first light ray L1, a positional relationship between an optical focus F of an imaging optical system including the translucent member WS and the reflecting section 13 and the display unit 12 is a first state in which the display unit 12 is closer to the exit 17 than the optical focus F, and when the display element 121 emits the second light ray L2, a positional relationship between the display unit 12 and the optical focus F is a second state in which the display unit 12 is closer to the light source 11 than the optical focus F, and wherein the second mirror 132 has a concave shape.

[0061] (Supplementary Note 2) The head-up display device according to Supplementary Note 1, wherein the first mirror has a concave shape.

[0062] (Appendix 3) The head-up display device described in Appendix 2, wherein the reflecting section 13 further includes a third mirror 133 that reflects the first light ray L1 reflected by the first mirror 131 and the second light ray L2 that passes through the first mirror 131 and is reflected by the second mirror 132 toward the translucent member WS, and the third mirror 133 has a concave shape.

[0063] (Supplementary Note 4) The head-up display device according to Supplementary Note 1, wherein the first mirror 131 has a concave shape, and a radius of curvature of the first mirror 131 is larger than a radius of curvature of the second mirror 132.

[0064] (Appendix 5) The head-up display device described in Appendix 4 is characterized in that the reflecting unit 13 further includes a third mirror 133 that reflects the first light ray L1 reflected by the first mirror 131 and the second light ray L2 that passes through the first mirror 131 and is reflected by the second mirror 132 toward the translucent member WS, and the radius of curvature of the third mirror 133 is larger than the radius of curvature of the first mirror 131.

[0065] (Supplementary Note 6) The head-up display device according to claim 5, wherein the radius of curvature of the third mirror 133 is larger than the radius of curvature of the second mirror 132.

[0066] (Note 7) A head-up display device 1 has an exit 17, and emits display light L from the exit 17 toward a light-transmitting member WS, thereby allowing a virtual image VI and a real image RI of a display image represented by the display light L to be visually recognized. The head-up display device 1 includes a display element 121, and a switching element 122 that is provided closer to the exit 17 along the optical path than the display element 121 and that can switch the polarization of the emitted light between a first polarization and a second polarization that are different from each other, and transmits light emitted by a light source 11. the display unit 12 reflecting the light representing the display image displayed on the display unit 12 toward the light-transmitting member WS; and a control unit 15 controlling the switching element 122. The reflecting unit 13 includes a first mirror 131 that reflects a first light ray L1 having a first polarization and transmits a second light ray L2 having a second polarization, and a second mirror 132 that reflects the second light ray L2. a head-up display device arranged such that, when the display element 121 emits the first light ray L1, a positional relationship between the optical focus F of an imaging optical system including the translucent member WS and the reflecting portion 13 and the display portion 12 is a first state in which the display portion 12 is closer to the exit 17 than the optical focus F, and when the display element 121 emits the second light ray L2, the display portion 12 is in a second state in which the display portion 12 is closer to the light source 11 than the optical focus F; and, by having an upper radius of curvature (R1U, R2U) and a lower radius of curvature (R1L, R2L) of at least one of the first mirror 131 and the second mirror 132 different from each other, the first mirror 131 and the second mirror 132 are configured such that a first angle of the virtual image VI viewed in the first state with respect to the road surface and a second angle of the real image RI viewed in the second state with respect to the road surface are different from each other.

[0067] (Supplementary Note 8) The head-up display device according to Supplementary Note 1, wherein the display unit 12 is disposed at an angle with respect to the axial direction of the optical path.

[0068] (Appendix 9) The head-up display device described in Appendix 2 is characterized in that the display unit 12 is tilted so that the upper side is toward the first mirror 131, and the radius of curvature R2U of the upper side of the second mirror 132 is larger than the radius of curvature R2L of the lower side, such that the first angle of the virtual image VI in the first state is less than 45° and the second angle of the real image RI in the second state is 45° or more.

[0069] (Supplementary Note 10) The head-up display device according to Supplementary Note 3, wherein the radius of curvature R1U of the upper side of the first mirror 131 is larger than the radius of curvature R1L of the lower side.

[0070] (Appendix 11) The display unit 12 is arranged at an angle such that the upper side is toward the first mirror 131, and the radius of curvature R1U of the upper side of the first mirror 131 is smaller than the radius of curvature R1L of the lower side, and the radius of curvature R2U of the upper side of the second mirror 132 is smaller than the radius of curvature R2L of the lower side, such that the first angle of the virtual image VI in the first state is 90° or more, and the second angle of the real image RI in the second state is 45° or more. This is the head-up display device described in Appendix 2.

[0071] (Appendix 12) The head-up display device according to appendix 1, wherein the display unit 12 is disposed perpendicular to the axial direction of the optical path.

[0072] (Appendix 13) The head-up display device described in Appendix 6 is characterized in that the radius of curvature R1U of the upper side of the first mirror 131 is larger than the radius of curvature R1L of the lower side, such that the first angle of the virtual image VI in the first state is less than 45° and the second angle of the real image RI in the second state is greater than or equal to 45°.

[0073] (Note 14) A head-up display device 1 has an exit 17, and emits display light L from the exit 17 toward a light-transmitting member WS, thereby allowing a virtual image VI and a real image RI of a display image represented by the display light L to be visually recognized. The head-up display device 1 includes a display element 121, and a switching element 122 that is provided on the exit 17 side along the optical path from the display element 121 and that can switch the polarization of the emitted light between a first polarization and a second polarization that are different from each other, and transmits light emitted by a light source 11. The display device includes a display unit 12 that reflects light representing the display image displayed on the display unit 12 toward the light-transmitting member WS, a reflecting unit 13 that reflects light representing the display image displayed on the display unit 12 toward the light-transmitting member WS, and a control unit 15 that controls the switching element 122. The reflecting unit 13 includes a first mirror 131 that reflects a first light ray L1 having a first polarization and transmits a second light ray L2 having a second polarization, and a second mirror 132 that reflects the second light ray L2. a head-up display device configured such that, when the display element 121 emits the first light ray L1, a positional relationship between the optical focus F of the imaging optical system including the translucent member WS and the reflecting portion 13 and the display portion 12 is a first state in which the display portion 12 is closer to the light source 11 than the optical focus F, and when the display element 121 emits the second light ray L2, the positional relationship between the display portion 12 is a first state in which the display portion 12 is closer to the light source 11 than the optical focus F, and a head-up display device configured such that, when the display element 121 emits the first light ray L1, a positional relationship between the optical focus F of the imaging optical system including the translucent member WS and the reflecting portion 13 and the display portion 12 is a first state in which the display portion 12 is closer to the light source 11 than the optical focus F, and when the display element 121 emits the second light ray L2, the positional relationship between the display portion 12 is a second state in which the display portion 12 is closer to the light source 11 than the optical focus F, and the first mirror 131 and the second mirror 132 are configured such that a first angle of the virtual image VI viewed in the first state with respect to the road surface and a second angle of the real image RI viewed in the second state with respect to the road surface are substantially identical to each other by having upper radii of curvature (R1U, R2U) and lower radii of curvature (R1L, R2L) of the first mirror 131 and the second mirror 132 differ from each other.

[0074] (Appendix 15) The head-up display device according to appendix 8, wherein the display unit 12 is disposed at an angle with respect to the axial direction of the optical path.

[0075] (Appendix 16) The head-up display device described in Appendix 9 is characterized in that the display unit 12 is arranged at an angle such that the upper side is toward the first mirror 131, and the radius of curvature R1U of the upper side of the first mirror 131 is smaller than the radius of curvature R1L of the lower side, and the radius of curvature R2U of the upper side of the second mirror 132 is larger than the radius of curvature R2L of the lower side, such that the first angle of the virtual image VI in the first state is 45° or more, and the second angle of the real image RI in the second state is 45° or more.

[0076] (Appendix 17) The head-up display device according to appendix 8, wherein the display unit 12 is disposed perpendicular to the axial direction of the optical path.

[0077] (Appendix 18) The head-up display device described in Appendix 11 is characterized in that the radius of curvature R1U of the upper side of the first mirror 131 is larger than the radius of curvature R1L of the lower side, and the radius of curvature R2U of the upper side of the second mirror 132 is smaller than the radius of curvature R2L of the lower side, such that the first angle of the virtual image VI in the first state is less than 45°, and the second angle of the real image RI in the second state is less than 45°. [Explanation of symbols]

[0078] C Vehicle DR Crew Member F optical focus L(L1,L2) Display light VI Virtual Image RI real image R1~R3 ​​Radius of curvature WS Windshield 1 HUD device 10 PGU 11 Light source 12 Display section 13 Reflector 15 Control section 16 Case 17 Opening 18 Coverslip 20 Switch 21 Display control unit 22 Display drive unit 30 Various Devices 121 Display element 122 Switching element 131 Mirror No. 1 132 2nd Mirror 133 3rd Mirror

Claims

1. A head-up display device having an emission port, and emitting display light from the emission port toward a light-transmitting member to allow a virtual image and a real image of a display image represented by the display light to be visually recognized, a display section including a display element and a switching element that is provided on the exit side along the optical path from the display element and is capable of switching the polarization of the emitted light between a first polarization and a second polarization that are different from each other, the display section transmitting light emitted by a light source and displaying the display image; a reflecting section that reflects light representing the display image displayed on the display section toward the light-transmitting member; A control unit that controls the switching element; having The reflecting portion is a first mirror that reflects a first light beam having the first polarization and transmits a second light beam having the second polarization; a second mirror that reflects the second light beam; Including, The first mirror and the second mirror are when the display element emits the first light ray, a positional relationship between an optical focal point of an imaging optical system including the light-transmitting member and the reflecting portion and the display portion becomes a first state in which the display portion is closer to the exit port than the optical focal point, When the display element emits the second light beam, the display unit is disposed in a second state in which the display unit is closer to the light source than the optical focus, The first mirror and the second mirror are configured such that a first angle of the virtual image viewed in the first state with respect to a road surface and a second angle of the real image viewed in the second state with respect to the road surface are substantially the same as each other by having a radius of curvature of an upper side and a radius of curvature of a lower side of the first mirror and the second mirror being different from each other. A head-up display device.

2. The display unit is Arranged at an angle to the axial direction of the optical path 2. The head-up display device according to claim 1.

3. the display unit is disposed at an angle such that an upper side faces the first mirror, The first mirror has a smaller radius of curvature than the lower side thereof, and the second mirror has a larger radius of curvature than the lower side thereof, so that the first angle of the virtual image in the first state is 45° or more, and the second angle of the real image in the second state is 45° or more.

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

4. The display unit is Arranged perpendicular to the axial direction of the optical path 2. The head-up display device according to claim 1.

5. The first mirror has a larger radius of curvature than the lower side thereof, and the second mirror has a smaller radius of curvature than the lower side thereof, so that the first angle of the virtual image in the first state is less than 45° and the second angle of the real image in the second state is less than 45°.

5. The head-up display device according to claim 4.

Images