WO2019077939A1 - Virtual image display device - Google Patents

Abstract

A HUD as a virtual image display device displays a virtual image so that an image is visible by projecting the image onto a projection screen. The HUD comprises: a polarizer (40) which reflects polarized light traveling in a first direction while transmitting polarized light traveling in a second direction perpendicular to the first direction; a liquid crystal display (20) that emits light for displaying an image toward the polarizer; a reflector (50) that reflects the display light, which is emitted from the liquid crystal display and transmitted through the polarizer, toward the polarizer again, to thus constitute a round-trip optical path (OP1) for causing the display light to travel to and from the polarizer; and a quarter-wave plate (60) provided on the round-trip optical path and changing the polarization direction of the display light so that the display light is guided to the projection screen via the polarizer on the return path. Thus, it is possible to improve the visibility of the virtual image.

Description

Virtual image display Cross-reference to related applications

This application is based on Japanese Patent Application No. 2017-203203 filed Oct. 20, 2017, the disclosure of which is incorporated by reference into the present application.

The present disclosure relates to a virtual image display device that displays a virtual image in a viewable manner.

2. Description of the Related Art Conventionally, there is known a virtual image display device that displays a virtual image so that the image can be viewed by projecting the image onto a projection unit. The virtual image display device disclosed in Patent Document 1 includes a concave mirror, an image light emitting unit, and a reflection mirror. At least a part of the concave mirror is provided with a half mirror area consisting of a half mirror. The image light emitting unit emits display light of the image toward the half mirror area. The reflection mirror forms a reciprocating light path for reciprocating the display light with the concave mirror by reflecting the display light transmitted through the half mirror region toward the reflection mirror. The light reflected by the reflection mirror is reflected toward the projection unit by the concave mirror including the half mirror area. Thus, the image is projected to the projection unit.

JP, 2017-15805, A

As described above, in the device of Patent Document 1, attempts are made to miniaturize the device while earning the optical path length by constructing a reciprocating light path. However, since the display light which constitutes a part of the virtual image is transmitted once in the half mirror region and reflected one more time, the display light is attenuated by, for example, about half at each transmission and reflection. That is, the energy efficiency is so low that the display light attenuates to a quarter or less after projection, and a sufficient brightness for the virtual image can not be obtained. Therefore, it was difficult to display a virtual image with good visibility.

One object disclosed is to provide a virtual image display device with good visibility of a virtual image.

The virtual image display device disclosed herein is a virtual image display device that displays a virtual image so that the image can be viewed visually by projecting the image onto the projection unit, and reflects polarized light in the first direction and can not be compared with the first direction. A polarization unit that transmits polarized light along a second orthogonal direction, an image light emission unit that emits display light of an image toward the polarization unit side, and a display light that has passed the polarization unit from the image light emission unit side again A reflecting unit that reflects light toward the projecting unit, and a reflecting unit that forms a reciprocating light path for causing display light to reciprocate between the polarizing unit and a reciprocating light path. And a quarter-wave plate for converting the polarization direction of the display light so as to be guided.

According to such a virtual image display device, the display light reciprocates between the polarization part and the reflection part by reflecting the display light which has passed through the polarization part from the image light emission part side toward the polarization part again. A reciprocating light path is configured. By disposing the 1⁄4 wavelength plate in such a reciprocating optical path, the polarization direction of the display light is converted, and the display light traveling on the return path of the reciprocating optical path is guided by the polarization unit to the projection unit side .

That is, the polarization direction of the display light when passing through the first polarization part is a direction along one of the first direction and the second direction in the polarization part. Thereafter, the display light is transmitted through the 1⁄4 wavelength plate twice in the reciprocating light path, and is incident again on the polarization part in a state where the polarization direction is converted into a direction substantially different by 90 degrees. At the time of re-incidence to the polarization unit, the polarization direction of the display light is the direction along the other of the first direction and the second direction in the polarization unit, so most of the display light does not return to the image light emitting unit side. It becomes possible to guide light to the projection unit side. Therefore, since it is possible to form a reciprocating light path for obtaining an optical path length while suppressing the attenuation of the display light, it is possible to display a high-luminance virtual image at an easy-to-see distance. According to the above, it is possible to provide a virtual image display device with good visibility of the virtual image.

It is a schematic diagram which shows the mounting state to the vehicle of the HUD apparatus of 1st Embodiment. It is a figure which shows schematic structure of the HUD apparatus of 1st Embodiment, Comprising: It is the figure which looked at a HUD apparatus in the direction from the left to the right. It is a figure which shows schematic structure of the HUD apparatus of 1st Embodiment, Comprising: It is the figure which looked at a HUD apparatus from the upper direction to the downward direction. It is a figure which shows schematic structure of the liquid crystal display of 1st Embodiment. It is a figure for demonstrating the polarization | polarized-light part of 1st Embodiment. It is a schematic diagram for demonstrating the behavior of the display light of 1st Embodiment. It is a figure corresponding to FIG. 2 in 2nd Embodiment. It is a figure corresponding to FIG. 3 in 2nd Embodiment. It is a figure corresponding to FIG. 6 in 2nd Embodiment. It is a figure corresponding to FIG. 2 in 3rd Embodiment. It is a figure corresponding to FIG. 6 in 3rd Embodiment. It is a figure corresponding to FIG. 2 in 4th Embodiment. It is a figure corresponding to FIG. 2 in 5th Embodiment. It is a figure corresponding to FIG. 2 in 6th Embodiment. It is a figure corresponding to FIG. 2 in 7th Embodiment. It is a figure corresponding to FIG. 6 in 7th Embodiment. It is a figure corresponding to FIG. 2 in 8th Embodiment. It is a figure corresponding to FIG. 2 in the modification 1. FIG. It is a figure corresponding to FIG. 3 in the modification 1. FIG. It is a figure corresponding to FIG. 2 in the modification 2. FIG. It is a figure corresponding to FIG. 3 in the modification 2. FIG. FIG. 26 is a view corresponding to FIG. 5 in an example of modification 6. FIG. 26 is a view corresponding to FIG. 5 in another example of the modification 6. FIG. 21 is a view corresponding to FIG. 2 in an example of modification 10. FIG. 21 is a view corresponding to FIG. 2 in another example of the modification 10. It is a figure corresponding to FIG. 2 in the modification 11. FIG. It is a figure corresponding to FIG. 2 in the modification 14. FIG. It is a figure corresponding to FIG. 2 in the modification 15. FIG. It is a figure corresponding to FIG. 2 in the modification 16. As shown in FIG. It is a figure corresponding to FIG. 2 in the modification 17. FIG.

Hereinafter, a plurality of embodiments will be described based on the drawings. In addition, the overlapping description may be abbreviate | omitted by attaching the same code | symbol to the corresponding component in each embodiment. When only a part of the configuration is described in each embodiment, the configuration of the other embodiments described above can be applied to other parts of the configuration. In addition to the combinations of the configurations explicitly described in the description of each embodiment, the configurations of the plurality of embodiments can be partially combined with each other even if they are not explicitly specified unless any problem occurs in the combination. .

First Embodiment
As shown in FIG. 1, the virtual image display device according to the first embodiment of the present disclosure is used in a vehicle 1 and is a head-up display device (hereinafter referred to as HUD device) housed in an instrument panel 2 of the vehicle 1. It is 100. The HUD device 100 projects an image toward the projection unit 3 a set on the windshield 3 of the vehicle 1. Thereby, the HUD device 100 displays a virtual image so that the image can be viewed visually by the occupant of the vehicle 1 as a viewer. That is, when the display light of the image reflected by the projection unit 3a reaches the viewing area EB set in the room of the vehicle 1, the occupant whose eye point EP is located in the viewing area EB is a virtual image of the display light Perceive as VRI. Then, the occupant can recognize various information displayed as a virtual image VRI. Examples of various information displayed as a virtual image as an image include information indicating the state of the vehicle 1 such as the vehicle speed and the remaining amount of fuel, or navigation information such as visibility auxiliary information and road information.

In the following, unless stated otherwise, the front, rear, front-rear direction, upper, lower, vertical, left, right, and left-right directions are described with reference to the vehicle 1 on the horizontal plane HP.

The windshield 3 of the vehicle 1 is formed of, for example, glass or synthetic resin in a translucent plate shape, and is disposed above the instrument panel 2. The windshield 3 forms the projection part 3a on which the display light is projected in a smooth concave or planar shape. The projection unit 3 a may not be provided on the windshield 3. For example, a combiner that is separate from the vehicle 1 may be installed in the vehicle 1, and the projector 3a may be provided in the combiner.

The visual recognition area EB is a space area that can be visually recognized so that the virtual image VRI displayed by the HUD device 100 satisfies a predetermined standard, and is also referred to as an eye box. The visual recognition area EB is typically set to overlap the eyedrops set in the vehicle 1. The eyedrops are set in an elliptical shape based on an eye range that statistically represents the distribution of the eye points EP of the occupant.

The specific configuration of such a HUD device 100 will be described below using FIGS. 2 to 6 as well. As shown in FIGS. 2 and 3, the HUD device 100 includes a housing 10, a liquid crystal display 20, a polarization unit 40, a reflection unit 50, a quarter wavelength plate 60, and the like. Since the HUD device 100 can be downsized, it can be easily mounted on the vehicle 1.

The housing 10 is made of, for example, a synthetic resin or metal and has a hollow shape for accommodating other elements of the HUD device 100 such as the liquid crystal display 20 and the reflection unit 50, and is installed in the instrument panel 2 of the vehicle 1. ing. The housing 10 has a window 11 which is optically opened on the upper surface facing the projection 3a. The window portion 11 is covered with a dustproof sheet 12 capable of transmitting display light.

The image light emitting unit emits display light of an image formed as a virtual image VRI. The image light emitting unit of the present embodiment is a liquid crystal display 20. The liquid crystal display 20 has a back light portion 21 and a liquid crystal panel 26, and is configured by, for example, accommodating them in a box-like casing 20a. As shown in FIG. 4, the backlight unit 21 includes, for example, a light source 22, a condenser lens 23, a field lens 24, and the like.

The light source 22 is configured, for example, by an array of a plurality of light emitting elements 22a. The light emitting element 22 a in the present embodiment is a light emitting diode element disposed on the light source circuit board 22 b and connected to a power supply. Each light emitting element 22 a emits light with a light emission amount corresponding to the amount of current when it is energized. In detail, in each light emitting element 22a, for example, pseudo white light emission is realized by covering a blue light emitting diode with a yellow phosphor.

The condenser lens 23 and the field lens 24 are disposed between the light source 22 and the liquid crystal panel 26. The condenser lens 23 is formed of, for example, a synthetic resin or glass so as to be translucent. In particular, the condenser lens 23 of the present embodiment is a lens array in which a plurality of convex lens elements are arranged in accordance with the number and arrangement of the light emitting elements 22a. The condenser lens 23 condenses the light incident from the light source 22 side and emits the light to the field lens 24 side.

The field lens 24 is disposed between the condenser lens 23 and the liquid crystal panel 26, and is formed of, for example, a synthetic resin or glass to have translucency. In particular, the field lens 24 of the present embodiment further condenses the light incident from the condenser lens 23 side, collimates it, and emits it toward the liquid crystal panel 26 side.

In addition, as a structure of the backlight part 21, various structures can be employ | adopted besides the above-mentioned structure.

The liquid crystal panel 26 of the present embodiment is a liquid crystal panel using thin film transistors (TFTs), and is, for example, an active matrix liquid crystal panel 26 formed of a plurality of liquid crystal pixels arranged in two directions. . In the liquid crystal panel 26, a liquid crystal layer or the like sandwiched between a pair of linear polarizers 27a and 27b and a pair of linear polarizers 27a and 27b is stacked. Each of the linear polarizers 27a and 27b transmits light polarized in a direction along the transmission axis TA, and blocks light polarized in a direction along an absorption axis orthogonal to the transmission axis TA. The pair of linear polarization plates 27a and 27b are disposed such that the transmission axes TA are substantially orthogonal to each other. The liquid crystal layer is capable of rotating the polarization direction of light incident on the liquid crystal layer according to the applied voltage by voltage application for each liquid crystal pixel.

The liquid crystal panel 26 can form an image by display light emitted from the display screen 28 by controlling the transmittance of the light for each liquid crystal pixel by the incidence of light from the backlight unit 21 side. ing. Adjacent liquid crystal pixels are provided with color filters of different colors (for example, red, green and blue), and various colors are realized by combining them. Here, the display light is emitted from the display screen 28 as linearly polarized light along the transmission axis TA of the linear polarizing plate 27b on the emission side. Thus, the display light is emitted from the display screen 28 toward the polarization unit 40 on the light path. The display light of this embodiment is mainly composed of light of a wavelength in the range of 380 to 780 nm. The liquid crystal display 20 of this embodiment emits display light from the front to the rear.

As shown in FIG. 2, for example, the polarizing unit 40 is formed in a flat plate shape by bonding the polarizing element 43 on the entire surface of the light transmitting substrate 41. The light transmitting substrate 41 is formed of, for example, a synthetic resin or glass in a light transmitting flat plate shape having substantially no polarization characteristic. The polarization unit 40 according to the present embodiment is disposed obliquely rearward of the liquid crystal display 20 so that the normal direction thereof is forward, downward, backward, and upward.

The polarizing element 43 has a polarization characteristic that reflects polarized light in the first direction D1 and transmits polarized light along a second direction D2 substantially orthogonal to the first direction D1 (see also FIG. 6). The polarizing element 43 of the present embodiment is, for example, a film-like reflective polarizing element such as DBEF (registered trademark) manufactured by 3M. In such a reflective polarizing element 43, the first direction D1 can be referred to as a reflection axis RA, and the second direction D2 can be referred to as a transmission axis TA. The polarizing element 43 is attached to, for example, the surface of the light transmitting substrate 41 opposite to the liquid crystal display 20 (that is, the surface on the side of the reflecting portion 50).

Here, the transmission axis TA of the polarizing element 43 is arranged in alignment with the transmission axis TA of the linear polarizing plate 27 b on the exit side of the liquid crystal panel 26. Therefore, the display light emitted from the display screen 28 of the liquid crystal panel 26 and obliquely incident on the polarization unit 40 at a predetermined incident angle is transmitted through the light transmitting substrate 41 and further transmitted through the polarizing element 43. The reflective unit 50 is disposed ahead of the display light transmitted through the polarizing unit 40 in this manner.

The reflecting portion 50 is a reflecting mirror in which a metal film such as aluminum is deposited as a reflecting surface 51 on a surface of a base material made of, for example, a synthetic resin or glass. The reflecting surface 51 is formed in a curved shape, and is curved in a concave shape, for example, such that the center of the reflecting portion 50 is recessed. That is, the reflection unit 50 is a positive optical element having a positive optical power. The reflective surface 51 of the present embodiment is disposed to face the front at the rear of the polarization unit 40.

The reflecting unit 50 reflects the display light, which has passed through the polarizing unit 40 from the liquid crystal display 20 side, toward the polarizing unit 40 again. Thus, the reflecting unit 50 constitutes a reciprocating light path OP1 for causing the display light to reciprocate between itself and the polarizing unit 40. The polarization unit 40 and the reflection unit 50 are arranged such that the incident angle and the reflection angle on the reflection surface 51 become smaller (for example, 20 degrees or less, preferably 10 degrees or less) by forming the reciprocating optical path OP1. It is possible to

Here, as shown in FIGS. 2 and 5, at the start of the forward path of the optical path OP1 in which the display light enters the polarization unit 40 from the liquid crystal display 20, the display light enters the polarization unit 40 on the polarization unit 40. The region is defined as a first incident region IR1. Furthermore, at the end of the return path of the reciprocating optical path OP1, a region on the polarization unit 40 where the display light enters the polarization unit 40 is defined as a second incident region IR2. Basically, the luminous flux spreads as the display light travels, so the area of the second incident area IR2 becomes wider than the area of the first incident area IR1. In the present embodiment, the entire first incident region IR1 is set to be included in the second incident region IR2. By doing this, it is possible to configure an optical system in which the incident angle and the reflection angle at the reflection surface 51 are reduced while the size of the polarization unit 40 is reduced.

Assuming that there is no element for converting the polarization direction of the display light in the reciprocating optical path OP1, the display light reflected by the reflection unit 50 maintains the polarization direction along the transmission axis TA of the polarizing element 43. As a result, the light is transmitted through the polarization unit 40 again. So, in this embodiment, as shown in FIG. 2, the quarter wavelength plate 60 is arrange | positioned in reciprocation optical path OP1.

The quarter-wave plate 60 is an optical element that causes a substantial 1/4 wavelength phase difference between the polarization along the fast axis FA and the polarization along the slow axis SA (also in FIG. 6). reference). The quarter wavelength plate 60 of the present embodiment is designed to correspond to any wavelength (380 to 780 nm) of the display light from the liquid crystal display 20, and the phase difference for one quarter wavelength is It is a phase difference included in the range of 95 to 195 nm in terms of distance. The quarter wave plate 60 is formed, for example, in a plate shape or a film shape using a birefringent material. The quarter-wave plate 60 is formed by being bonded to the surface of the polarization unit 40 on the side of the reflection unit 50. As shown in FIG. 6, the fast axis FA and the slow axis SA of the quarter-wave plate 60 form an angle of substantially 45 degrees with respect to the transmission axis TA and the reflection axis RA of the polarizing element 43. Is located in

Therefore, the display light reciprocated in the reciprocating optical path OP1 passes through the quarter wavelength plate 60 twice in total, once in the forward path and in the backward path. Specifically, the display light is converted from right-handed circularly polarized light to left-handed circularly polarized light from linearly polarized light in the polarization direction along the transmission axis TA of the polarizing element 43 by the action of the quarter-wave plate 60 in the outward path. Ru. Then, when the light is reflected by the reflection unit 50, the display light becomes circularly polarized light in the reverse direction to that before the incident. Although the display light is converted from the above-mentioned circularly polarized light into linearly polarized light by the action of the quarter-wave plate 60 in the return path, the polarization direction is reversely rotated during reflection. , Along the reflection axis RA of the polarizing element 43.

As a result, since the polarization direction of the display light is along the reflection axis RA of the polarizing element 43 when the display light enters the polarization unit 40 in the return path, the display light is projected by the polarization unit 40 to the projection unit 3a. It is reflected to the side. That is, the polarization direction of the display light is converted by the 1⁄4 wavelength plate 60 so that the display light is guided to the projection unit 3 a side.

Since the display light reflected by the polarization unit 40 is once again converted to circularly polarized light since it is transmitted through the 1⁄4 wavelength plate 60, it is transmitted through the window unit 11 and emitted to the outside of the housing 10 and projected onto the projection unit 3a Be done. Thus, the occupant can visually recognize the virtual image VRI.

Here, as shown in FIG. 2, the dustproof sheet 12 of the present embodiment is formed in a curved plate shape by bonding the color temperature conversion filter 12b to the entire surface of the light transmitting substrate 12a. The light transmitting substrate 12a is made of, for example, a synthetic resin or glass. The color temperature conversion filter 12 b has wavelength dependency on the transmittance, and adjusts the color temperature of the virtual image VRI by adjusting the transmission amount of each wavelength of the display light after transmission of the 1⁄4 wavelength plate 60. Convert. That is, since the retardation value of the quarter-wave plate 60 has a slight wavelength dependency, when the display light reaches the dustproof sheet 12, the tint changes as compared with that when it is emitted from the display screen 28. However, the color temperature conversion filter 12b adjusts this color to return to the state when emitted from the display screen 28. Thus, when the color temperature of the virtual image VRI approaches the color temperature of the image on the display screen 28, the reproducibility of the tint of the virtual image VRI is enhanced.

The virtual image VRI is displayed larger than the display screen 28 of the liquid crystal panel 26 by curving the reflection surface 51 of the reflection unit 50 in a concave shape. In the enlargement of the virtual image VRI, since the reflecting surface 51 to which the enlargement action is applied is set at the turning point of the reciprocating optical path OP1, it is possible to set the incident angle at the time of reflection small as described above. There is. Therefore, distortion of the vertically asymmetric (or bilaterally asymmetric) virtual image VRI that may occur together with the magnifying action can be suppressed.

(Action effect)
The effects and advantages of the first embodiment described above will be described again below.

According to the first embodiment, the display light is polarized by the display unit 50 reflecting the display light that has passed through the polarizing unit 40 from the liquid crystal display 20 side as the image light emitting unit toward the polarizing unit 40 again. A reciprocating optical path OP1 is configured to reciprocate between the portion 40 and the reflecting portion 50. By arranging the 1⁄4 wavelength plate 60 in the reciprocating optical path OP1, the polarization direction of the display light is converted, and the display light traveling in the return path of the reciprocating optical path OP1 is guided by the polarizing unit 40 to the projection unit 3a side. Will be

That is, the polarization direction of the display light when passing through the first polarization unit 40 is a direction along one of the first direction D1 and the second direction D2 in the polarization unit 40. Thereafter, the display light is transmitted twice through the 1⁄4 wavelength plate 60 in the reciprocating optical path OP1, and is incident again on the polarization unit 40 in a state in which the polarization direction is substantially 90 degrees different. At the time of re-incident on the polarization unit 40, the polarization direction of the display light is the direction along the other of the first direction D1 and the second direction D2 in the polarization unit 40, so most of the display light is on the liquid crystal display 20 side. The light can be guided to the projection unit 3a side without returning to the above. Therefore, since it is possible to configure the reciprocating optical path OP1 for obtaining the optical path length while suppressing the attenuation of the display light in the polarization unit 40, it is possible to display the high-luminance virtual image VRI at an easy-to-see distance. According to the above, it is possible to provide the HUD device 100 having good visibility of the virtual image VRI.

Further, according to the first embodiment, the polarization unit 40 transmits the display light from the liquid crystal display 20 side toward the reflection unit 50, and the quarter-wave plate 60 transmits the display light in the return path of the reciprocation optical path OP1. The polarization direction of the display light is converted to a direction along the first direction D1 so that the light is reflected by the polarization unit 40 toward the projection unit 3a. According to such a configuration, it is possible to easily realize the reciprocating optical path OP1 in which the display light reciprocates between the polarization unit 40 and the reflection unit 50 while suppressing the attenuation of the display light in the polarization unit 40.

Further, according to the first embodiment, the quarter wavelength plate 60 is formed in a state of being bonded to the polarization unit 40. In this way, the provision of a unique structure for holding the quarter-wave plate 60 can be suppressed. Moreover, in the bonding to the flat plate-like polarization part 40, the occurrence of wrinkles and the like as in the case of bonding to a curved surface can be suppressed.

Further, according to the first embodiment, the polarization section 40 is formed in a flat plate shape, and the reflection surface 51 of the reflection section 50 is formed in a curved surface shape. Therefore, the incident angle and the reflection angle can be obtained by disposing the display light at the turning point of the reciprocating optical path OP1 without causing the display light to have a magnifying function at the time of reflection by the polarizing unit 40 where the incident angle and the reflection angle become relatively large. At the time of reflection at the reflection portion 50, the display light is caused to have a magnifying action. For this reason, distortion of the vertically asymmetric (or left-right asymmetry) virtual image VRI that occurs together with the magnifying action can be suppressed. Therefore, the visibility of the virtual image VRI can be made better.

Further, according to the first embodiment, the entire area of the first incident region IR1 is included in the second incident region IR2. In this way, both incident areas IR1 and IR2 can be overlapped as much as possible. Therefore, since the size of the polarization part 40 can be miniaturized, the HUD device 100 itself can be miniaturized accordingly.

Second Embodiment
As shown in FIGS. 7 to 9, the second embodiment is a modification of the first embodiment. The second embodiment will be described focusing on differences from the first embodiment.

The liquid crystal display 220 corresponding to the image light emitting portion in the second embodiment has an internal configuration similar to that of the first embodiment as shown in FIGS. It is designed to emit light.

The polarization unit 240 of the second embodiment is housed inside the housing 10, and is disposed obliquely above the liquid crystal display 220 so that the normal direction is upward and slightly forward or downward and slightly backward. It is done. The polarization part 240 is formed by bonding the polarization element 243 on the entire surface of the light transmitting substrate 241 as in the first embodiment. More specifically, the polarizing element 243 is attached to, for example, the surface of the light transmitting substrate 241 on the liquid crystal display 220 side and the reflecting portion 250 side.

Here, the reflection axis RA of the polarizing element 243 according to the second embodiment is disposed in alignment with the transmission axis TA of the linear polarizing plate 27b on the exit side of the liquid crystal panel 26 (see also FIG. 9). Therefore, display light emitted from the display screen 28 and obliquely incident on the polarization unit 240 at a predetermined incident angle is reflected by the polarization element 243. Thus, the reflection unit 250 is disposed at the end of the display light reflected by the polarization unit 240.

The reflective surface 251 of the reflective section 250 of the second embodiment is arranged to be directed upward and slightly rearward, below the polarization section 240 and in front of the liquid crystal display 220. In this manner, the reflection unit 250 constitutes a reciprocation optical path OP1 for causing the display light to reciprocate between itself and the polarization unit 240, as in the first embodiment.

The 1⁄4 wavelength plate 260 of the second embodiment is formed in a film shape, and is disposed by being bonded to the reflection surface 251 of the reflection unit 250. Then, as shown in FIG. 9, the fast axis FA and the slow axis SA of the quarter-wave plate 260 have an angle of substantially 45 degrees with respect to the transmission axis TA and the reflection axis RA of the polarizing element 243. It is arranged in a way.

Therefore, as in the first embodiment, the display light reciprocated in the reciprocating optical path OP1 passes through the quarter wavelength plate 260 twice in total, once in the forward path and in the backward path. Specifically, the display light is converted from right-handed circularly polarized light to left-handed circularly polarized light from linearly polarized light in the polarization direction along the transmission axis TA of the polarizing element 243 by the action of the quarter-wave plate 260 in the outward path. Ru. Then, when the light is reflected by the reflection unit 250, the display light becomes circularly polarized light in the opposite direction to that before the incident. Although the display light is converted from the above-mentioned circularly polarized light into linearly polarized light by the action of the quarter-wave plate 260 in the return path, the polarization direction is reversely rotated during reflection. , Along the transmission axis TA of the polarizing element 243.

As a result, since the polarization direction of the display light is along the transmission axis TA of the polarizing element 243 at the time when the display light is incident on the polarization unit 240 in the double path, the display light is projected on the polarization unit 240 It penetrates to the 3a side. That is, the polarization direction of the display light is converted by the 1⁄4 wavelength plate 260 so that the display light is guided to the projection unit 3 a side.

According to the second embodiment described above, the polarizing unit 240 reflects the display light from the liquid crystal display 220 toward the reflecting unit 250, and the quarter-wave plate 260 displays the light in the return path of the reciprocating optical path OP1. The polarization direction of the display light is converted to a direction along the second direction D2 so that the light is transmitted to the projection unit 3a side by the polarization unit 240. According to such a configuration, it is possible to easily realize the reciprocating optical path OP1 in which the display light reciprocates between the polarization unit 240 and the reflection unit 250 while suppressing the attenuation of the display light in the polarization unit 240.

Third Embodiment
As shown in FIGS. 10 and 11, the third embodiment is a modification of the second embodiment. The third embodiment will be described focusing on differences from the second embodiment.

The quarter-wave plate 360 of the third embodiment is formed by being bonded to the surface of the polarization unit 240 on the liquid crystal display 320 side and the reflection unit 250 side. The fast axis FA and the slow axis SA of the quarter-wave plate 360 are arranged to form an angle of substantially 45 degrees with respect to the transmission axis TA and the reflection axis RA of the polarizing element 243.

On the other hand, in the liquid crystal display 320 of the third embodiment, the liquid crystal panel 326 is configured by bonding another quarter wave plate 329 to the display screen 328. The fast axis FA and the slow axis SA of the quarter-wave plate 329 are arranged to form an angle of substantially 45 degrees with respect to the transmission axis TA of the linear polarization plate 27 b on the exit side of the liquid crystal panel 326 It is done. Therefore, the liquid crystal display 320 emits display light as right-handed circularly polarized light or left-handed circularly polarized light, not linearly polarized light. Whether the circularly polarized light emitted by the liquid crystal display 320 is clockwise or counterclockwise depends on the polarization direction of the display light converted to linear polarization when the display light first passes through the 1⁄4 wavelength plate 360. It is selected to be in a direction along the reflection axis RA of the polarizing element 243. Therefore, the display light obliquely transmitted to the polarization unit 240 at a predetermined incident angle after being transmitted through the 1⁄4 wavelength plate 360 is reflected by the polarization element 243 toward the reflection unit 250.

From here, the display light reciprocates in the reciprocating optical path OP1, but reciprocates twice in total in the reciprocating optical path OP1 twice each in the forward path and the return path as in the second embodiment. Therefore, when the display light again enters the polarization unit 240 in the forward path, the display light is transmitted through the polarization unit 240 because the polarization direction of the display light is along the transmission axis TA of the polarization element 243.

According to the third embodiment described above, at the time of the first incidence from the liquid crystal display 220 to the 1⁄4 wavelength plate 360, the display light is incident as circularly polarized light. Therefore, the display light can be made to be linearly polarized light along the first direction D1 in the polarization unit 240 according to the setting of the fast axis FA and the slow axis SA of the quarter-wave plate 360. The axis alignment for realizing an optical system which reflects display light with high reflectance from the above to the reflection part 250 becomes easy. Therefore, since it is possible to configure the reciprocating optical path OP1 for obtaining the optical path length while suppressing the attenuation of the display light in the polarization unit 240, it is possible to display the high-luminance virtual image VRI at an easy-to-see distance.

Fourth Embodiment
As shown in FIG. 12, the fourth embodiment is a modification of the second embodiment. The fourth embodiment will be described focusing on differences from the second embodiment.

The polarization part 440 of the fourth embodiment is arranged to close the whole of the window part 11 of the housing 610. That is, the polarization unit 440 is also used as a dustproof sheet that prevents foreign matter (for example, dust, dust, water) from invading the inside of the housing 610 from the outside of the housing 610.

In addition, due to the arrangement of the polarization unit 440, for example, the polarization unit 440 shields part of external light such as sunlight transmitted through the windshield 3 and incident on the window unit 11 into the interior of the housing 610. Intrusion of external light is also suppressed.

Furthermore, in the polarization unit 440 of the present embodiment, the surface on the side of the projection unit 3a is curved in a concave shape, and the surface on the liquid crystal display 220 and the reflection unit 250 side is curved in a convex shape. Is formed in a curved plate shape. For this reason, the display light emitted from the liquid crystal display 220 is reflected by the convex curved surface of the polarizing section 440, and then reflected by the reflective section 251 by the concave reflecting surface 251, and further, has a substantially constant thickness. The light is transmitted through the polarization unit 440 of Therefore, the telecentricity on the liquid crystal display 220 side can be improved in the optical system based on the display light formed as the virtual image VRI. Therefore, the display quality of virtual image VRI realized using liquid crystal panel 26 can be enhanced while securing the size of viewing region EB.

According to the fourth embodiment described above, the polarizing section 440 is also used as a dustproof sheet by closing the window section 11. Since the component for realizing the optical system in which the reciprocating optical path OP1 is configured and the component for realizing the dustproof sheet are shared, the virtual image can be suppressed while suppressing an increase in the physical size of the HUD device 100 by suppressing the number of components. High visibility of VRI can be realized.

Fifth Embodiment
As shown in FIG. 13, the fifth embodiment is a modification of the first embodiment. The fifth embodiment will be described focusing on differences from the first embodiment.

The HUD device 100 of the fifth embodiment further includes a light blocking unit 570. The light blocking portion 570 is formed to have a light absorbing property, for example, of polyurethane colored in dark color such as black, and integrally includes a light blocking hood portion 571 and a light blocking laminated portion 573.

The light blocking hood portion 571 is formed in a wall shape between the liquid crystal display 20 and the polarizing portion 40 along the traveling direction of the display light and so as not to block the light flux of the display light. The light blocking hood portion 571 blocks stray light such as external light by absorption or the like, thereby preventing the stray light from being reflected in the virtual image VRI due to multiple reflection.

The light blocking laminated portion 573 is disposed in close contact with or in close contact with the surface of the polarizing portion 40 on the liquid crystal display 20 side in a region overlapping the second incident region IR2 except the first incident region IR1. Are arranged in a stacked state with the polarization unit 40. The light blocking laminate portion 573 suppresses degradation or damage of the liquid crystal panel 26 or the like of the liquid crystal display 20 by blocking the light passing through the polarizing portion 40 among the external light by absorption or the like.

Furthermore, even if part of the display light reflected by the reflection unit 50 and incident on the polarization unit 40 again passes through the polarization element 43 of the polarization unit 40, the light blocking laminate unit 573 Absorb. Thus, it is possible to suppress a situation in which the transmitted light is reflected by the surface of the polarizing unit 40 on the liquid crystal display 20 side to the projection unit 3 a side and a double image is generated in the virtual image VRI.

According to the fifth embodiment described above, the polarization unit 40 and the light blocking laminated unit 573 in the laminated state are disposed corresponding to the area excluding the first incident area IR1 on the liquid crystal display 20 side of the polarization unit 40, It blocks light that attempts to transmit the polarizing unit 40 from the reflective unit 50 side to the liquid crystal display 20 side. Such blocking of light suppresses deterioration or damage of the liquid crystal display 20, so that high visibility of the virtual image VRI can be maintained over a long time.

Sixth Embodiment
As shown in FIG. 14, the sixth embodiment is a modification of the first embodiment. The sixth embodiment will be described focusing on differences from the first embodiment.

The housing 610 of the sixth embodiment has a reflector holding wall 613, a polarization part holding wall 614, and a display hole 615 in its inside.

The reflective portion holding wall 613 is formed in a wall shape so as to abut on the opposite side to the reflective surface 51 in the reflective portion 50. The reflection portion holding wall 613 holds the reflection portion 50 by bonding, fitting, fastening, or the like.

The polarization part holding wall 614 is formed in a wall shape so as to abut on a part of the polarization part 40 on the side opposite to the reflection part 50 (that is, the liquid crystal display 620 side). The polarization part holding wall 614 holds the polarization part 40 by bonding, fitting, fastening, or the like.

In detail, the polarization part holding wall 614 brings the surface 614 a into close contact with the area of the polarization part 40 on the liquid crystal display 620 side excluding the first incident area IR1, that is, the part substantially corresponding to the second incident area IR2. ing. The surface 614a of the polarization holding wall 614 is formed in, for example, a dark color (for example, black) which can regulate the reflection of light. As a result, similarly to the light blocking laminated portion 573 of the fifth embodiment, the polarizing portion holding wall 614 exerts the blocking effect of the light transmitted through the polarizing portion 40 among the external light and the suppressing effect of the double image.

The display hole 615 is formed in the shape of a hole opened in the polarization part holding wall 614 at a portion corresponding to the first incident region IR1 of the polarization part 40. Although the display hole 615 of this embodiment is formed in the shape of a through hole penetrating the housing 610, it may be formed in the shape of a bottomed hole. The display hole 615 is a quadrangular frustum shaped hole which is gradually narrowed as it is separated from the polarization section 40.

The liquid crystal display 620 corresponding to the image light emitting unit in the sixth embodiment is disposed at a position apart from the polarizing unit 40 in the display hole 615. In the liquid crystal display 620, the liquid crystal panel 26 is opposed to the polarization unit 40, and a part of the backlight unit 21 is disposed outside the housing 610. For this reason, the liquid crystal display 620 causes the heat generated by the backlight unit 21 to generate a stray light blocking action on the side wall 615 a of the display hole 615 like the light blocking hood unit 571 of the fifth embodiment. It is possible to dissipate heat easily to the outside.

According to the sixth embodiment described above, the polarization unit holding wall 614 holding the polarization unit 40 and bringing the surface 614 a into close contact with the liquid crystal display 620 side of the polarization unit 40 corresponds to the polarization unit 40 on the reflection unit 50 side. Blocks the light that is to be transmitted to the liquid crystal display 620 side. By blocking the light, deterioration or damage of the liquid crystal display 620 is suppressed, so that high visibility of the virtual image VRI can be maintained for a long time. And, by making the holding structure of the polarization unit 40 and the light blocking structure in common, by suppressing the number of parts, it is possible to realize high visibility of the virtual image VRI while suppressing an increase in the size of the HUD device 100. Can.

Seventh Embodiment
As shown in FIGS. 15 and 16, the seventh embodiment is a modification of the first embodiment. The seventh embodiment will be described focusing on differences from the first embodiment.

The polarization part 740 of the seventh embodiment is formed in a curved plate shape in which the surface on the side of the reflection part 50 is concavely curved. The 1⁄4 wavelength plate 760 is formed in a film shape, and is disposed by being bonded to the reflection surface 51 of the reflection unit 50. The fast axis FA and the slow axis SA of the quarter-wave plate 760 are arranged to form an angle of substantially 45 degrees with respect to the transmission axis TA and the reflection axis RA of the polarizing element 743. (See Figure 16). Therefore, as in the first embodiment, as in the first embodiment, the display light reciprocated in the reciprocating optical path OP1 passes through the quarter wavelength plate 760 twice in total, once in the forward path and in the backward path. The polarization direction is converted as in the first embodiment. However, since the display light wave after being reflected by the polarization part 740 does not pass through the 1⁄4 wavelength plate 760, it enters the window part 11 as it is linearly polarized light.

A polarization direction change unit 755 is provided in the HUD device 100 according to the seventh embodiment. The polarization direction changer 755 can change the direction of the polarization unit 740 by rotating the polarization unit 740 around, for example, a rotation axis 756 extending in the left and right direction using a stepping motor. ing. At this time, the direction of the rotation axis 756 is set such that the directions of the effective reflection axis RA and the transmission axis TA with respect to the polarization direction of the display light are maintained. For example, when the direction of the rotation axis 756 matches the direction of one of the reflection axis RA and the transmission axis TA, the transmittance and the reflectance change in the polarization unit 740 even if the direction of the polarization unit 740 is changed. Can be suppressed as much as possible.

When the direction of the polarization unit 740 is changed, the traveling direction of the display light after the display light is reflected to the projection unit 3a is changed in the return path of the reciprocating optical path OP1. Therefore, the position where the virtual image VRI is projected in the projection unit 3a is changed up and down. As a result, the display position of the virtual image VRI moves up and down, and at the same time, the visual recognition area EB can also move up and down. That is, the appearance of the virtual image VRI can be adjusted in accordance with the position of the occupant's actual eye point EP or the occupant's preference.

According to the seventh embodiment described above, in the configuration in which the display light from the liquid crystal display 20 is transmitted by the polarization unit 740 and is guided to the reciprocating optical path OP1, the polarization unit direction change unit 755 changes the direction of the polarization unit 740. Do. When display light is transmitted, there is little influence by the direction of the polarization unit 740. Therefore, while changing the direction of the polarization unit 40 while maintaining the form of the reciprocation light path OP1 between the polarization unit 740 and the reflection unit 50 It is possible to adjust the appearance of the virtual image VRI by changing the reflection direction to the projection unit 3a after passing through OP1. Therefore, high visibility of virtual image VRI can be realized.

Eighth Embodiment
As shown in FIG. 17, the eighth embodiment is a modification of the first embodiment. The eighth embodiment will be described focusing on differences from the first embodiment.

In the eighth embodiment, a convex mirror 875 is provided on the optical path of the display light from the liquid crystal display 820 as an image light emitting unit to the polarizing unit 40. The convex mirror 875 forms a metal film by depositing a metal such as aluminum as the reflective surface 876. The reflecting surface 876 is formed in a curved shape, and is curved in a convex shape such that the center of the convex mirror 875 protrudes, for example. That is, the convex mirror 875 is a negative optical element having negative optical power. The reflective surface 876 in the present embodiment is disposed at a position adjacent to the polarization unit 40 so as to face the rear and the lower diagonal direction.

In the eighth embodiment, the liquid crystal display 820 emits display light forward and upward toward the convex mirror 875. The display light emitted from the liquid crystal display 820 is reflected by the reflective surface 876 so that the display light is incident on the polarization unit 40.

According to the eighth embodiment described above, the convex mirror 875 having negative optical power is provided on the light path from the liquid crystal display 820 to the polarizing unit 40. With such a convex mirror 875, the telecentricity on the liquid crystal display 820 side can be enhanced for display light imaged as a virtual image VRI. That is, it is possible to secure the size of the visual recognition area EB while narrowing the viewing angle of the liquid crystal display 820 to improve the quality of the image. Therefore, high visibility of virtual image VRI can be realized.

(Other embodiments)
As mentioned above, although a plurality of embodiments were described, the present disclosure should not be construed as being limited to these embodiments, and applied to various embodiments and combinations within the scope of the gist of the present disclosure. Can.

As the first modification, particularly in the first and fifth to eighth embodiments, the liquid crystal display 20, the polarization unit 40, the reflection unit 50, and the like may be arranged differently. Specifically, in the examples of FIGS. 18 and 19 in which the arrangement of the first embodiment is reversed, the liquid crystal display 20 emits display light from the rear toward the front. The polarization unit 40 is disposed obliquely in front of the liquid crystal display 20 so that the normal direction thereof is backward, downward, forward, and upward. The reflective surface 51 of the reflective unit 50 is disposed to face the rear in front of the polarizing unit 40.

As the second modification, particularly with regard to the second to fourth embodiments, the liquid crystal display 220, the polarization unit 240, the reflection unit 250, and the like may be arranged differently. Specifically, in the examples of FIGS. 20 and 21 in which the arrangement of the second embodiment is changed, the liquid crystal display 220 emits display light from the front toward the rear. The polarization unit 240 is disposed obliquely rearward of the liquid crystal display 220 so that the normal direction thereof is forward, downward, backward, and upward. The reflective surface 251 of the reflective unit 250 is disposed below the polarization unit 240 so as to face upward and slightly backward.

As a third modification, the quarter wavelength plate 60 may not be attached to the polarization unit 40 or the reflection unit 50 as long as the quarter wavelength plate 60 is provided in the reciprocating light path OP1. For example, the quarter-wave plate 60 may be independently disposed between the polarization unit 40 and the reflection unit 50 on the reciprocating optical path OP1.

As a fourth modification, the quarter wavelength plate 60 may not be configured of a single plate. For example, on the reciprocating optical path OP1, mutually advancing 1/8 wavelength plates which generate a phase difference of substantially 1/8 wavelength between polarization along the fast axis FA and polarization along the slow axis SA By arranging a total of two phase axes FA and slow axes SA, a configuration may be provided in which a quarter wave plate 60 is substantially provided. Further, the fast axis FA or the slow axis SA of the quarter wavelength plate 60 may form an angle of, for example, 40 to 50 degrees with respect to the first direction D1 or the second direction D2.

As a fifth modification, the polarization element 43 in the polarization section 40 may be provided on either side of the light transmitting substrate 41.

As the sixth modification, particularly with regard to the first and fifth to eighth embodiments, in the polarization section 40, the polarization element 43 may be formed not in the entire surface of the polarization section 40 but only in a partial region. As shown in FIGS. 22 and 23, the polarizing element 43 may be disposed only in the first incident region IR 1, and a region other than the first incident region IR 1 in the polarizing unit 40 serves as a reflective surface 44 such as aluminum. The metal film may be formed by depositing or the like. Further, as shown in FIG. 23, a part of the display light may pass through the polarization part 40, and the other part may pass through the side of the polarization part 40 as it is to reach the reciprocating optical path OP1.

As the modification 7, various configurations can be adopted as the configuration of the polarization unit 40. For example, as the polarizing element 43, a polarizing element using a wire grid may be employed. The wire grid polarization element is formed, for example, in a film shape, and includes a plurality of metal wires extending substantially parallel to one another. The plurality of metal wires are made of, for example, aluminum or the like, and are arranged at a predetermined pitch. Here, the predetermined pitch is set to be smaller than most of the wavelengths of the display light. In such a wire grid polarization element, the extending direction of the metal wire corresponds to the first direction D1 or the reflection axis RA, and the direction orthogonal to the extending direction corresponds to the second direction D2 or the transmission axis TA.

As a modification 8, a plate type polarization beam splitter can be adopted as still another configuration of the polarization unit 40. The polarization beam splitter reflects, for example, S polarized light and transmits P polarized light. That is, the polarization direction of S-polarization corresponds to the first direction D1, and the polarization direction of P-polarization corresponds to the second direction D2.

As a modified example 9, an anti-reflection film may be provided on each surface through which display light such as the polarization unit 40 and the dustproof sheet 12 passes.

As a modification 10, the polarization unit 40 may be provided in a curved plate shape as shown in FIGS. 24 and 25, and the surface thereof is a spherical shape, a cylindrical surface shape, or a free curved surface shape including a saddle point It may be formed in Similarly, the reflecting surface 51 of the reflecting portion 50 or the reflecting surface 876 of the convex mirror 875 may be formed into a spherical shape, a cylindrical surface, a free-form surface including a saddle point, or the like.

As a modification 11 of the fourth embodiment, as shown in FIG. 26, the polarizing portion 440 which is also used as a dustproof sheet may be formed in a flat plate shape.

As a modified example 12 of the fifth embodiment, the light blocking laminate portion 573 may be provided by forming a paint film other than polyurethane, for example, a light shielding film or a polarizing portion 240.

As a modification 13, for example, a display other than the liquid crystal display 20 using the liquid crystal panel 26 as an image light emitting unit, such as a DLP (Digital Light Processing; registered trademark) type display, a laser scanner type display, etc. It can be adopted. In a DLP display, light from a light emitting element is directed to an array of minute digital mirror elements that can be switched between on and off states, and light is reflected by only the on state digital mirror elements. Is formed, and the display light of the image is emitted. In a laser scanner type display, an image is formed on a screen by scanning the laser light by causing the laser light to be incident on the micro mirror and changing the direction of the micro mirror, and the display light of the image Is emitted.

As the modification 14, the light blocking hood portion 571 as in the fifth embodiment may be applied to the configurations of the liquid crystal display 220, the polarization unit 240, and the reflection unit 250 of the second to fourth embodiments. . In this case, as shown in FIG. 27, it is preferable that the light blocking hood portion 571 be disposed so as not to interfere with the reciprocating optical path OP1.

As a fifteenth modification, for example, as shown in FIG. 28, with respect to the configurations of the liquid crystal display 220, the polarization unit 240, and the reflection unit 250 of the second to fourth embodiments, the reflection unit holding as in the sixth embodiment The wall 613 may be applied.

As a modification 16, a reflection unit direction change unit 257 for changing the direction of the reflection unit 250 is further provided to the configurations of the liquid crystal display 220, the polarization unit 240, and the reflection unit 250 of the second to fourth embodiments. It may be As shown in FIG. 29, the reflecting portion direction changing portion 257 rotates the reflecting portion 250 around the rotation axis 258 extending in the left and right direction, for example, using a stepping motor, thereby setting the direction of the reflecting portion 250. It is possible to change. When the direction of the reflection unit 250 is changed, the traveling direction of the display light after the display light is reflected by the projection unit 3a is changed in the return path of the reciprocating light path OP1. Therefore, the position where the virtual image VRI is projected in the projection unit 3a is changed up and down.

As a modification 17, as shown in FIG. 30, a convex mirror 875 as in the sixth embodiment is applied to the configurations of the liquid crystal display 220, the polarization unit 240, and the reflection unit 250 of the second to fourth embodiments. You may

As a modification 18, the virtual image display device can be applied to various vehicles such as an aircraft, a ship, or a non-moving casing.

Although the disclosure has been described with reference to examples, it is understood that the disclosure is not limited to the disclosed examples or structures. Rather, the present disclosure includes various modifications and variations within the equivalent range. In addition, although various elements of the present disclosure are illustrated by various combinations and forms, other combinations and forms including more elements, fewer elements, or only one of these elements Are also within the scope and scope of the present disclosure.

Claims (12)

A virtual image display device for displaying a virtual image so that the image can be viewed visually by projecting the image onto a projection unit (3a),
A polarization unit (40, 240, 440, 740) that reflects polarized light in a first direction (D1) and transmits polarized light along a second direction (D2) orthogonal to the first direction;
An image light emitting unit (20, 220, 320, 820) that emits display light of the image toward the polarizing unit;
A reflection unit that reflects the display light, which has passed through the polarization unit from the image light emission unit side, toward the polarization unit again, and has a reciprocating optical path (OP1) for reciprocating the display light with the polarization unit The reflective part (50, 250) to constitute,
A quarter-wave plate (60, 260, 360) provided on the reciprocating light path to convert the polarization direction of the display light so that the display light is guided to the projection unit side by the polarization unit in the return path. , 760). The polarizing unit transmits the display light from the image light emitting unit toward the reflecting unit.
The quarter-wave plate has a polarization direction of the display light along the first direction such that the display light is reflected by the polarization unit toward the projection unit in the return path of the reciprocating light path. The virtual image display device according to claim 1, which performs conversion. It is arranged corresponding to the area except the area (IR1) where the display light is incident on the polarization section at the start of the forward path of the reciprocating light path on the image light emission section side of the polarization section, The virtual image according to claim 2, further comprising: a light blocking laminate portion (573) for blocking light which is transmitted from the reflective portion side to the image light emitting portion side. Display device. It is formed in the shape of a wall that holds the polarization unit and makes the surface adhere to the image light emission unit side among the polarization units, and tries to transmit the polarization unit from the reflection unit side to the image emission unit side The virtual image display apparatus according to claim 2, further comprising a polarization unit holding wall (614) that blocks light. The virtual image display device according to any one of claims 2 to 4, further comprising a polarization unit direction change unit (755) that changes the orientation of the polarization unit. The polarization unit reflects the display light from the image light emitting unit side toward the reflection unit,
The quarter wavelength plate converts the polarization direction of the display light in the second direction so that the display light is transmitted to the projection unit side by the polarization unit in the return path of the reciprocating light path. The virtual image display device according to claim 1. It further comprises a housing (610) for housing the image light emitting unit and the reflecting unit,
The housing has a window (11) for directing the display light toward the projection unit and emitting the light to the outside of the housing.
The virtual image display apparatus according to claim 6, wherein the polarization unit is also used as a dustproof sheet by closing the window unit. The virtual image display device according to any one of claims 1 to 7, wherein the quarter wavelength plate is formed in a state of being bonded to the polarization unit. The virtual image display device according to any one of claims 1 to 7, wherein the quarter wavelength plate is formed in a state of being bonded to the reflection portion. The virtual image display device according to any one of claims 1 to 9, wherein the polarization section is formed in a flat plate shape, and the reflection surface of the reflection section is formed in a curved surface shape. The virtual image display device according to any one of claims 1 to 10, further comprising: a negative optical element (875) having negative optical power on an optical path from the image light emitting unit to the polarization unit. When the forward path of the reciprocating optical path is started, the entire area of the first incident region (IR1), which is the area where the display light enters the polarizing portion, is the polarizing light portion when the backward path of the reciprocating optical path is completed. The virtual image display device according to any one of claims 1 to 11, wherein the virtual image display device is included in a second incident area (IR2) which is an incident area.

Images