Head-up display device

Abstract

To provide a head-up display device which, while suppressing the effect of external light, minimizes the degradation of a display unit.SOLUTION: The present invention comprises: a display unit 12 that includes a display element 35 and a polarization conversion element 36 capable of switching the polarization of emitted light between first polarization and second polarization before outputting, and that passes light emitted by a light source 11 through and displays a display image; a reflection unit 13 for reflecting light expressing the display image toward a windshield WS; and a control unit 15 for controlling the polarization conversion element 36. The reflection unit 13 includes a first mirror reflecting a first beam of light that constitutes first polarized light, and a second mirror that reflects a second beam of light that constitutes second polarized light. The present invention further includes a correction lens 37 for correcting the display image and provided between the polarization conversion element 36 and the first mirror 131, and an other retardation plate 39 for converting linear polarization and appropriately circular polarization and provided between the correction lens 37 and the first mirror 131.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 while eliminating the influence of external light. [Background technology]

[0002] A known conventional electronic device is described in, for example, Patent Document 1. This electronic device has a cluster display unit and a HUD attached to the instrument panel, determines the vehicle's driving state, and adjusts the focal length of the HUD based on the determination result so that the position of the virtual image of the projected image is near the cluster display unit or in front of the windshield. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6516642 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional electronic devices, external light such as sunlight can penetrate the windshield and enter the HUD during the day. The external light that enters the HUD is reflected by the mirror optical system and hits the display unit, which is a liquid crystal display, and then reflects off the display unit, causing the driver to see the light as dazzling. In addition, as described above, there is a problem in that the external light hitting the liquid crystal display generates heat, causing the liquid crystal display to become warm and deteriorate.

[0005] Therefore, the present invention has been made in consideration of the above problems, and has an object to provide a head-up display device that minimizes deterioration of the display unit while suppressing the influence of external light. [Means for solving the problem]

[0006] The present invention provides a head-up display device 1 having an outlet 17, which emits display light L (L1, L2) from the outlet 17 toward a light-transmitting member WS, thereby allowing a display image represented by the display light L to be visually recognized, the head-up display device 1 including a display element 35 and a switching output unit 36 that is provided closer to the outlet 17 along an optical path than the display element 35 and that is capable of switching the polarization of the emitted light between a first polarized light and a second polarized light that are different from each other and outputting the light; a display unit 12 that transmits light emitted by a light source 11 and displays the display image; and a light that represents the display image displayed on the display unit 12, which is transmitted through the light-transmitting member WS. and a control unit 15 that controls the switching output unit 36, wherein the reflecting unit 13 includes a first mirror 131 that reflects a first light ray having the first polarization and transmits a second light ray having the second polarization, and a second mirror 132 that reflects the second light ray, and is characterized by comprising: a correcting lens 37 that is provided along the optical path between the switching output unit 36 and the first mirror 131 and corrects the display image; and a first retardation plate 39 that is provided between the correcting lens 37 and the first mirror 131 and converts linearly polarized light to approximately circularly polarized light. [Effects of the Invention]

[0007] According to the present invention, it is possible to prevent external light incident on the head-up display device from being reflected by the display unit and being visually dazzling to the driver. Furthermore, by reflecting the external light incident on the head-up display device by the correction lens, heat generation in the display unit can be suppressed, and deterioration due to heat can be prevented. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a configuration for generating a virtual image in a head-up display device according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing a configuration for generating a real image in a head-up display device according to an embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram showing the configuration of a PGU in a head-up display device according to an embodiment of the present invention. [Figure 4] 2 is a schematic diagram showing an optical path and a polarization state in a head-up display device according to an embodiment of the present invention. FIG. [Figure 5] FIG. 2 is a functional block diagram showing the configuration of a PGU when controlling display content and polarization switching control in a head-up display device according to an embodiment of the present invention. [Figure 6] 3A and 3B are diagrams showing optical paths and polarization states when external light is incident on a head-up display device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] An 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 referred to as an 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.

[0010] 1 and 2, the HUD device 1 includes a light source 11 that is made up of, for example, light-emitting diodes that emit light in the visible wavelength range and are mounted on a printed circuit board (PCB) 31, and that emits white light; a display element 35 that generates an image using the light incident from the light source 11; a polarization conversion element 36 (switching output unit) that switches the polarization of the light emitted from the display element 35 between first polarization and second polarization that are different from each other and outputs the light; a display unit 12 that transmits the light emitted from the light source 11 and displays a display image; a retardation plate 38 (second retardation plate) that is provided on the subsequent side (opposite the light source 11 side) of the polarization conversion element 36 along the optical path of the light that represents the display image generated by the display unit 12 and that converts linearly polarized light and approximately circularly polarized light; The display device includes a correction lens 37 provided downstream of the retarder 38 to correct the display image generated by the display unit 12, another retarder 39 (first retarder) provided downstream of the correction lens 37 to convert linearly polarized light into approximately circularly polarized light, a reflector 13 that reflects display light L (display light L1 representing a display image of a virtual image VI in the case of FIG. 1, and display light L2 representing a display image of a real image RI in the case of FIG. 2) emitted from the other retarder 39 toward a windshield WS (translucent member), and a control unit 15 that controls the display content of the display unit 12 and controls switching between the first polarized light and the second polarized light by the polarization conversion element 36, and these are housed in a housing 16. The housing 16 is provided with an opening 17 (exit port) through which the display light L is emitted, and a cover glass 18 is disposed in the opening 17 to protect the interior. The polarization conversion element 36 is an example of a switching output section, one retardation plate 38 is an example of a second retardation plate, the other retardation plate 39 is an example of a first retardation plate, the window shield WS is an example of a light-emitting member, and the opening 17 is an example of an exit port.

[0011] 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 reflector 13 and is emitted from an opening 17 in 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.

[0012] 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, remaining energy, route guidance such as turn-by-turn directions and maps, blind spot indicators, and warnings 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 text and icons indicating this information as well as background portions, and in a planar view from the occupant DR, they have, for example, a substantially rectangular shape.

[0013] 1 and 2, a detailed configuration of a PGU (Picture Generation Unit) including the light source 11, the display unit 12, one retarder 38, another retarder 39, and the correction lens 37 will be described. Fig. 3 is a schematic diagram showing the configuration of the PGU in the HUD device 1 according to this embodiment, and Fig. 4 is a schematic diagram showing the optical path and polarization state in the HUD device 1 according to this embodiment.

[0014] In FIG. 3, a plurality of light sources 11 are arranged at approximately equal intervals on a PCB 31. As described above, the light sources 11 are light-emitting diodes (LEDs) that emit light in the visible wavelength range. The direction of the optical axis S, which is the most intense light beam of the light source 11, is the same as the normal to the PCB 31 (hereinafter referred to as the first normal n1). A condenser lens 32 is provided on the light beam exit side of the light source 11. The condenser lens 32 collimates the light radially emitted from the light source 11. A lenticular lens 33 and a diffuser plate 34 are provided downstream of the condenser lens 32. The lenticular lens 33 and the diffuser plate 34 homogenize the light emitted from the condenser lens 32. The normals (hereinafter referred to as the second normal n2) of the condenser lens 32, the lenticular lens 33, and the diffuser plate 34 are arranged so that they coincide with the direction of the optical axis S. In other words, the condenser lens 32, the lenticular lens 33, and the diffuser plate 34 are arranged so that they are parallel to the PCB 31.

[0015] A display element 35 is disposed downstream of the diffuser plate 34. The display element 35 is made of, for example, a TFT liquid crystal (Thin Film Transistor Liquid Crystal) and generates an image using light emitted from the light source 11. A polarization conversion element 36 is disposed downstream of the display element 35. The polarization conversion element 36 is made of, for example, a 1 / 2λ plate and can rotate the polarization direction of linearly polarized image light emitted from the display element 35 by up to 90 degrees. As shown in FIG. 4, the polarization conversion element 36 is disposed such that the polarization axis (here, horizontal axis) shifted by approximately 45 degrees relative to the polarization axis (here, vertical axis) of the display element 35 becomes the fast axis. As a result, the image light transmitted through the polarization conversion element 36 becomes S-polarized light with the horizontal axis relative to the vertical axis of the display element 35.

[0016] Furthermore, the polarization conversion element 36 has a fast axis that can rotate 11.25 degrees along the surface, with the axis being the direction of the second normal n2. That is, the image light that passes through the polarization conversion element 36 can be switched between a first light ray that is a first S-polarized light (first polarization) that differs by 22.5 degrees from the polarization direction of the image light, and a second light ray that is a second S-polarized light (second polarization). In FIG. 4, the first S-polarized light is indicated by a dotted line, and the second S-polarized light is indicated by a dashed-dotted line. Here, the polarization conversion element 36 is configured to mechanically rotate a 1 / 2λ plate by controlling, for example, a motor or the like with the control unit 15. The rotation angle is not limited to ±11.25 degrees, but can be rotated by any angle under the control of the control unit 15. Note that, instead of a 1 / 2λ plate, the polarization conversion element 36 may also be a liquid crystal device that can switch the polarization direction under the ON / OFF control of the control unit 15.

[0017] A correction lens 37 is disposed downstream of the polarization conversion element 36, with a first retardation plate 38 (second retardation plate) and another retardation plate 39 (first retardation plate) disposed upstream of the correction lens 37. The first retardation plate 38 and the other retardation plate 39 are, for example, quarter-lambda plates, and convert linearly polarized light with a polarization azimuth angle of 45 degrees or less into approximately circularly polarized light (including circularly polarized light and elliptically polarized light), or vice versa. The first retardation plate 38 and the other retardation plate 39 are disposed so that their fast axes are shifted by 45 degrees relative to the vertical polarization axis of the display element 35. That is, as shown in FIG. 4, the linearly polarized image light (first S-polarized light indicated by the dotted line and second S-polarized light indicated by the dashed-dotted line) emitted from the polarization conversion element 36 passes through the first retardation plate 38 and the other retardation plate 39, and the polarization azimuth angle is shifted by 90 degrees. As a result, the first S-polarized light and the second S-polarized light on the vertical axis become the first S-polarized light and the second S-polarized light on the horizontal axis.

[0018] Furthermore, the first retardation plate 38 and the second retardation plate 39 are capable of converting linearly polarized light having a polarization azimuth angle of 45 degrees or more into approximately circularly polarized light. That is, as shown in FIG. 4 , the image light is converted from linearly polarized light to approximately circularly polarized light by the first retardation plate 38, and is converted from approximately circularly polarized light to linearly polarized light by the second retardation plate 39, and is then emitted to the reflecting unit 13.

[0019] The correction lens 37 is made of, for example, a transparent synthetic resin and is formed into a substantially triangular shape in a side view. The correction lens 37 corrects image distortion on the correction surface. Stray light occurs in the correction lens 37, but as described above, by placing the first retardation plate 38 and the second retardation plate 39 on either side of the correction lens 37, it is possible to eliminate the stray light generated by the correction lens 37. As shown in FIG. 3 , the second normal n2 direction of the display element 35, the polarization conversion element 36, the first retardation plate 38, the correction lens 37, and the second retardation plate 39 is inclined at θ with respect to the optical axis S (or a predetermined cross section of the first normal n1). In other words, these are arranged non-parallel to the PCB 31. This causes the second normal n2 direction to be misaligned with the optical axis S, making it possible to soften and reduce reflection of external light.

[0020] The image light transmitted through the other retardation plates 39 is emitted to the reflecting unit 13 as display light L. As shown in FIGS. 1 and 2, the reflecting unit 13 includes a first mirror 131, a second mirror 132, and a third mirror 133, each of which may be flat or curved. The display light L is reflected by the first mirror 131 and the third mirror 133, or by the second mirror 132 and the third mirror 133 and guided to the windshield WS, allowing the occupant DR to view a display image (a virtual image VI or a real image RI).

[0021] In reality, countless light rays are emitted from PGU 10, but for the sake of simplicity, in Figures 1 and 2, the light ray emitted from the center of the display unit 12 and passing through the center of the eyebox of the occupant DR is referred to as display light L, and the first light ray, display light L, reflected by the first mirror 131 is referred to as display light L1, and the second light ray, display light L, reflected by the second mirror 132 is referred to as L2.

[0022] The first mirror 131 and the second mirror 132 each have the property of reflecting or transmitting light rays having a specific polarization, and here, for example, the first mirror 131 reflects display light L1 having a first S-polarized light on the horizontal axis and transmits display light L2 having a second S-polarized light on the horizontal axis. On the other hand, the second mirror 132 transmits display light L1 having the first S-polarized light on the horizontal axis and reflects display light L2 having the second S-polarized light on the horizontal axis.

[0023] 1, the display light L1 reflected by the first mirror 131 is reflected by the third mirror 133 and the windshield WS, and is then viewed by the occupant DR. An optical focus F1 of the optical system consisting of the first mirror 131, the third mirror 133, and the windshield WS is located on the front side of the PGU 10 (first state). As a result, the display light L1 is focused on the outside of the vehicle D across the windshield WS, and is viewed by the occupant DR as a virtual image VI.

[0024] 2, the display light L2 transmitted through the first mirror 131 and reflected by the second mirror 132 is transmitted through the first mirror 131 again, reflected by the third mirror 133, and reflected by the windshield WS, and is then viewed by the occupant DR. An optical focus F2 of the optical system consisting of the second mirror 132, the third mirror 133, and the windshield WS is provided on the rear side of the PGU 10 (second state). As a result, the display light L2 is imaged inside the vehicle D across the windshield WS, and is viewed as a real image RI by the occupant DR.

[0025] The control unit 15 shown in Figures 1 and 2 controls the display content on the display element 35 and controls the switching of polarization on the polarization conversion element 36. The processing of the control unit 15 will be explained in detail using Figure 5. Figure 5 is a functional block diagram showing the configuration of the PGU 10 when controlling the display content and switching of polarization in the HUD device 1 according to this embodiment. Note that Figure 5 shows only the minimum necessary configuration directly related to the above processing, and other known configurations are omitted. In Figure 5, the PGU 10 includes the control unit 15, a light source 11, and a display unit 12. The control unit 15 includes a display control unit 21 that issues a command to the display unit 12 to generate any image light based on information sent from various devices 40, such as devices that acquire information, such as a vehicle speed sensor, an IMU (Inertial Measurement Unit) sensor, and a fuel sender, devices that process the acquired information, a navigation device, a RADAR (Radio Detecting and Ranging), and a LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), and a display unit drive unit 22 that controls the switching of the polarization direction based on a signal sent from a switch 20 in response to, for example, a change in driving mode (manual driving, automatic driving) or a change in driving location.

[0026] As described above, the display unit 12 also includes a display element 35, which is a TFT liquid crystal that forms arbitrary image light in accordance with a signal sent from the display control unit 21, and a polarization conversion element 36 that switches the polarization direction of the emitted image light in accordance with a signal sent from the display unit drive unit 22.

[0027] In the configuration of FIG. 5 , for example, during manual driving, the display unit driver 22 controls the polarization conversion element 36 to emit first S-polarized light (display light L1) on the horizontal axis, which is the first polarization, based on a signal transmitted from the switch 20. At this time, the display controller 21 controls the display element 35 to generate image light representing the vehicle information, route guidance information, warning displays, and the like, as described above. Furthermore, during autonomous driving, for example, the display unit driver 22 controls the polarization conversion element 36 to emit second S-polarized light (display light L2) on the horizontal axis, which is the second polarization, based on a signal transmitted from the switch 20. At this time, the display controller 21 controls the display element 35 to generate image light representing the assistant or agent supporting the occupant DR, as well as characters representing them, as described above. Then, light rays emitted from the light source 11 pass through the display unit 12, which has been controlled as described above, and are emitted as display light L to the reflector 13 via one retarder 38, another retarder 39, and the correction lens 37.

[0028] The display light L reflected by the reflector 13 is emitted from the opening 17 of the housing 16 through the cover glass 18 to the windshield WS. 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.

[0029] FIG. 6 is a diagram showing the optical path and polarization state when external light is incident on the HUD device 1 according to this embodiment. In FIG. 6, when external light such as sunlight enters the HUD device 1 during the day, it is reflected by the third mirror 133. Of the external light reflected by the third mirror 133, the first S-polarized component (dotted line) on the horizontal axis is reflected by the first mirror 131, and the second S-polarized component (dashed line) is transmitted. The second mirror 132 reflects the second S-polarized component (dashed line) on the horizontal axis. The other components are transmitted through the first mirror 131 and the second mirror 132 and are absorbed by the housing 16. It is desirable that the housing 16 be black in order to minimize reflection of external light.

[0030] The first S-polarized light component reflected by the first mirror 131 and the second S-polarized light component reflected by the second mirror 132 pass through another retardation plate 39 and are converted from linearly polarized light to approximately circularly polarized light. The approximately circularly polarized external light is reflected directly by the correction lens 37 and then passes through another retardation plate 39 again, where it is converted from approximately circularly polarized light to linearly polarized light. At this time, the external light, which was the first S-polarized light and the second S-polarized light on the horizontal axis, passes through the other retardation plate 39 twice, becoming the first S-polarized light and the second S-polarized light components on the vertical axis, which are shifted by 90 degrees. The first S-polarized light and the second S-polarized light components on the vertical axis are not reflected by the first mirror 131 and the second mirror 132, but are transmitted directly and absorbed by the housing 16. In other words, as shown in FIG. 6, even if external light enters the HUD device 1, the reflected light is not emitted again from the HUD device 1, thereby preventing the occupant DR from visually recognizing the external light.

[0031] As described above, the HUD device 1 according to this embodiment has an opening 17, and emits display light L from the opening 17 toward the windshield WS, thereby allowing the user to view a virtual image VI and a real image RI of a display image represented by the display light L. The HUD device 1 includes a display element 35 and a polarization conversion element 36 that is provided closer to the opening 17 along the optical path than the display element 35 and that is capable of switching the polarization of the emitted light between a first polarization and a second polarization that are different from each other and outputting the light. The HUD device 1 also includes a display unit 12 that transmits light emitted by a light source 11 and displays a display image, and a polarization conversion element 36 that converts light representing the display image displayed on the display unit 12 into a light that is projected onto the windshield WS. The optical system includes a reflector 13 that reflects light toward S, and a control unit 15 that controls the polarization conversion element 36. The reflector 13 includes a first mirror 131 that reflects a first light ray that has a first polarization and transmits a second light ray that has a second polarization, and a second mirror 132 that reflects the second light ray. The optical system also includes a correcting lens 37 that corrects the displayed image and another retardation plate 39 that is provided between the correcting lens 37 and the first mirror 131 along the optical path and converts linearly polarized light to approximately circularly polarized light. Therefore, reflected external light does not return from the opening 17 and reach the eyes of the occupant DR. In other words, when external light enters through the opening 17, it enters via the opening 17, the first mirror 131 or the second mirror 132, and the other retardation plate 39. After being converted from linearly polarized light to approximately circularly polarized light by the other retarder 39, the external light is reflected by the corrector lens 37 and folded back, and enters the other retarder 39 as approximately circularly polarized light, where it is converted from approximately circularly polarized light to linearly polarized light. At this time, the linearly polarized light has a polarization azimuth angle (for example, 90°) different from that of the linearly polarized light incident on the other retarder 39 from the first mirror 131. As a result, the external light incident on the first mirror 131 from the other retarder 39 is transmitted through the first mirror 131 without being reflected, and reaches the second mirror 132. Also, at the second mirror 132, most of the external light is transmitted through without being reflected, or even if there is a reflected component, it is not reflected in a direction toward the opening 17. Therefore, the external light is not visible to the occupant DR.

[0032] Furthermore, since the display element 35 can be prevented from being exposed to external light, the temperature of the display element 35 can be prevented from rising, and deterioration can be prevented.

[0033] Furthermore, since the polarization conversion element 36 is a 1 / 2λ plate that can be rotated by the driving force of the driving unit, by mechanically rotating the 1 / 2λ plate, it is possible to realize a device that switches between and outputs the first polarization (first S-polarized light on the horizontal axis) and the second polarization (second S-polarized light on the horizontal axis).

[0034] Furthermore, since the other retardation plate 39 is a 1 / 4λ plate, when the external light incident from the opening 17 is converted from linearly polarized light to approximately circularly polarized light, and then the external light reflected by the correction lens 37 and turned back is converted from approximately circularly polarized light to linearly polarized light, the difference in polarization azimuth angle between the linearly polarized light at the time of incidence and the linearly polarized light at the time of emission after turning back can be made 90 degrees, thereby preventing the external light from being perceived as dazzling light by the occupant DR.

[0035] Furthermore, since the optical system further includes a retardation plate 38 that is provided between the polarization conversion element 36 and the correction lens 37 and converts linearly polarized light to approximately circularly polarized light, the display light L emitted from the light source 11 and transmitted through the display unit 12 is converted from linearly polarized light to approximately circularly polarized light by the retardation plate 38, and then converted from approximately circularly polarized light to linearly polarized light when passing through another retardation plate 39 provided on the opening 17 side of the correction lens 37, and can be output to the reflection unit 13.

[0036] Furthermore, since one retardation plate 38 is a 1 / 4λ plate, the incident linearly polarized light is converted into approximately circularly polarized light by the 1 / 4λ plate, and then passed through the correction lens 37, where it can be smoothly converted into linearly polarized light by the other 1 / 4λ plate serving as the retardation plate 39.

[0037] Furthermore, since the second normal n2 direction of at least the display element 35, the polarization conversion element 36, and one of the retardation plates 38 forms a predetermined angle θ (where θ>0) with respect to the optical axis direction of the light source 11, by tilting the second normal n2 direction away from the optical axis direction, it is possible to reliably suppress the behavior of external light being reflected toward the opening 17.

[0038] Furthermore, the first mirror 131 and the second mirror 132 are arranged so that when the display element 35 emits the first light ray of the first polarization (first S-polarized light on the horizontal axis), the positional relationship between the optical focus F1 of the imaging optical system including the windshield WS and the reflector 13 and the display unit 12 is in a first state in which the display unit 12 is closer to the opening 17 than the optical focus F1, allowing the virtual image VI to be viewed, and when the display element 35 emits the second light ray (second S-polarized light on the horizontal axis), the positional relationship between the display unit 12 and the optical focus F2 is in a second state in which the display unit 12 is closer to the light source 11 than the optical focus F2, allowing the real image RI to be viewed.Therefore, by allowing the occupant DR to view the virtual image VI by emitting the first light ray and the real image RI by emitting the second light ray, the switching between the virtual image VI and the real image RI can be performed smoothly and reliably by switching the light emission. [Explanation of symbols]

[0039] C vehicle DR crew L(L1,L2) Display light n1 1st normal n2 Second normal RI real image S optical axis VI Virtual Image WS Window Shield 1 HUD device 10 PGU 11 Light source 12 Display section 13 Reflector 15 Control Unit 16 Case 17 Opening 18 Coverslips 20 Switch 21 Display control unit 22 Display drive unit 31 PCB 32 Condenser Lens 33 Lenticular Lens 34 Diffuser 35 Display element 36 Polarization conversion element 37 Corrective Lenses 38. One retardation plate 39 Other retarders 40 Various Devices 131 1st Mirror 132 Second Mirror 133 Third 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 display image represented by the display light to be visually recognized, a display element; and a switching output unit that is provided closer to the exit port along the optical path than the display element and is capable of switching the polarization of emitted light between a first polarized light and a second polarized light that are different from each other, and outputs the light, the display unit transmitting light emitted by the 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 output unit; and The reflecting portion is a first mirror that reflects a first light ray having the first polarization and transmits a second light ray having the second polarization; a second mirror that reflects the second light beam; Including, and, a correction lens provided along the optical path between the switching output unit and the first mirror, the correction lens correcting the display image; a first retardation plate provided between the correction lens and the first mirror, which converts linearly polarized light into substantially circularly polarized light; A head-up display device comprising:

2. The switching output unit It is a 1 / 2λ plate that can be rotated by the driving force of the driving unit.

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

3. The first retardation plate is a 1 / 4λ plate.

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

4. The optical system further includes a second retardation plate that is provided between the switching output unit and the correction lens and converts the linearly polarized light into the substantially circularly polarized light.

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

5. The second retardation plate is a 1 / 4λ plate.

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

6. The normal directions of the display element, the switching output unit, and the first retardation plate form a predetermined angle θ (where θ>0) with respect to the optical axis direction of the light source.

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

7. The first mirror and the second mirror are When the display element emits the first light ray, a positional relationship between an optical focus 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 focus, thereby allowing a virtual image to be viewed, When the display element emits the second light beam, the display unit is in a second state in which it is closer to the light source than the optical focus, and a real image is visually recognized.

7. The head-up display device according to claim 1, wherein the head-up display device is arranged as follows:

Images