JP2022013652A - Display system - Google Patents

Abstract

To provide a display system capable of suppressing external light from being reflected in a first mirror.SOLUTION: A display system 2 includes: a display element 12 having a display surface 16 emitting light showing an image; a concave mirror 26 reflecting the light emitted from the display surface 16 of the display element 12; and an optical element 28 disposed so as to face to the concave mirror 26 and containing a phase difference plate 46 and a transmission type polarizing plate 52 as a polarization element. The concave mirror 26 and the optical element 28 are disposed separately from the display element 12. The optical element 28 (i) transmits reflected light that light emitted from the display surface 16 of the display element 12 is reflected on the concave mirror 26, and (ii) reflects external light entering from the side where the reflected light is emitted to the optical element 28 and also reflected on the concave mirror 26, on a surface facing the concave mirror 26 of the optical element 28.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a display system for displaying an image.

A so-called electronic mirror is known in which a camera mounted on a vehicle captures the rear of the vehicle and a rear-view image captured by the camera is displayed on a rear-view mirror type display device in the vehicle (see, for example, Patent Document 1). ).

The display device of Patent Document 1 includes a display housed in an overhead console of a vehicle and a concave mirror suspended from a windshield of the vehicle. The display shows a rear image taken by the camera.

The light representing the rear image from the display is reflected by the concave mirror and is incident on the driver's eyes. By seeing the rear image reflected by the concave mirror, the driver appears to the driver that the virtual image of the rear image is displayed at the display position in front of the vehicle rather than the concave mirror.

Japanese Patent No. 5286750

In the display device of Patent Document 1, since the concave mirror is exposed to the outside of the overhead console, there is a problem that external light from the rear of the vehicle (for example, the headlight of the following vehicle or sunlight) is reflected on the concave mirror. Occurs.

Therefore, the present disclosure provides a display system capable of suppressing reflection of external light on the first mirror.

The display system according to one aspect of the present disclosure is a display system mounted on a moving body and displaying an image to a user, and is a display element having a display surface that emits light representing the image and the display element. A first mirror that reflects light emitted from the display surface of the above, and an optical element that is arranged to face the first mirror and includes a retardation plate and a polarizing element. The optical element is arranged separately from the display element, and the optical element (i) transmits the reflected light emitted from the display surface of the display element and reflected by the first mirror. (Ii) External light incident on the optical element from the side from which the reflected light is emitted and reflected by the first mirror is reflected on the surface of the optical element facing the first mirror.

According to the display system according to one aspect of the present disclosure, it is possible to suppress the reflection of external light on the first mirror.

It is a figure which shows an example of the vehicle which carried out the display system which concerns on Embodiment 1. FIG. It is sectional drawing of the display system which concerns on Embodiment 1. FIG. It is a figure which shows the positional relationship in the top view of the display element, the concave mirror, and the optical element of the display system which concerns on Embodiment 1. FIG. It is a schematic diagram for demonstrating the operation of the display system which concerns on Embodiment 1. FIG. It is sectional drawing of the display system which concerns on Embodiment 2. FIG. It is sectional drawing of the liquid crystal mirror which concerns on the modification of Embodiment 2. It is sectional drawing of the display system which concerns on Embodiment 3 in an electronic mirror mode. It is sectional drawing of the display system which concerns on Embodiment 3 in an optical mirror mode. It is a schematic diagram for demonstrating the operation of the display system which concerns on Embodiment 3. FIG. It is sectional drawing of the display system which concerns on Embodiment 4 in an electronic mirror mode. It is sectional drawing of the display system which concerns on Embodiment 4 in an optical mirror mode. It is sectional drawing of the display system which concerns on Embodiment 5. FIG. It is sectional drawing of the display system which concerns on Embodiment 6 in an electronic mirror mode. It is sectional drawing of the display system which concerns on Embodiment 6 in an optical mirror mode. It is a front view which shows the concave mirror, the optical element and the half mirror of the display system which concerns on Embodiment 6. It is sectional drawing of the display system which concerns on the modification of Embodiment 6 in the electronic mirror mode. It is sectional drawing of the display system which concerns on Embodiment 7 in an electronic mirror mode. It is sectional drawing of the display system which concerns on Embodiment 7 in an optical mirror mode. It is sectional drawing of the display system which concerns on the modification of Embodiment 7 in an electronic mirror mode. It is sectional drawing of the display system which concerns on Embodiment 8. It is a figure which shows an example of the vehicle which mounted the display system which concerns on Embodiment 9. It is sectional drawing of the display system which concerns on Embodiment 9. FIG. It is a perspective view which shows the internal structure of the display system which concerns on Embodiment 9. FIG. It is a schematic diagram for demonstrating the operation of the display system which concerns on Embodiment 9. FIG. It is a figure for comparing the display system which concerns on Embodiment 9 and the display system which concerns on a comparative example. It is sectional drawing of the display system which concerns on Embodiment 10. FIG. It is a schematic diagram for demonstrating the operation of the display system which concerns on Embodiment 10. It is sectional drawing of the display system which concerns on Embodiment 11. FIG. It is sectional drawing of the display system which concerns on Embodiment 12. It is sectional drawing of the display system which concerns on Embodiment 13. It is sectional drawing of the display system which concerns on Embodiment 14. It is sectional drawing of the display system which concerns on Embodiment 15. FIG. It is a schematic diagram which shows the display system which concerns on Embodiment 16. It is a schematic diagram which shows the display system which concerns on the comparative example. It is a schematic diagram which shows the display system which concerns on the comparative example. It is a front view which shows the mirror which concerns on the modification.

The display system according to one aspect of the present disclosure is a display system mounted on a moving body and displaying an image to a user, and is a display element having a display surface that emits light representing the image and the display element. A first mirror that reflects light emitted from the display surface of the above, and an optical element that is arranged to face the first mirror and includes a retardation plate and a polarizing element. The optical element is arranged separately from the display element, and the optical element (i) transmits the reflected light emitted from the display surface of the display element and reflected by the first mirror. (Ii) External light incident on the optical element from the side from which the reflected light is emitted and reflected by the first mirror is reflected on the surface of the optical element facing the first mirror.

According to this aspect, the optical element has a retardation plate and a polarizing element, and is arranged so as to face the first mirror. As a result, for example, even when external light from the rear of the moving body is incident on the optical element, the external light transmitted through the optical element is reflected by the first mirror and then becomes the first mirror of the optical element. Reflects on opposite surfaces. As a result, it is possible to suppress the reflection of external light on the first mirror.

In the display system according to one aspect of the present disclosure, the display element is fixed to the moving body, the display system is further rotatably supported with respect to the moving body, and the display surface of the display element is supported. It is provided with an optical reflecting unit having an incident portion for incident light emitted from the light and an emitting portion for emitting the incident light toward the user's eyes, and the optical reflecting portion includes the first mirror and the first mirror. The optical element arranged in the emitting portion, and the light emitted from the display surface of the display element is reflected by the first mirror at least once, and the retardation plate and the retardation plate of the optical element and the optical element are reflected. The polarizing elements are transmitted in this order and incident on the user's eyes.

According to this aspect, the optical element has a retardation plate and a polarizing element, and is arranged at the exit portion of the optical reflection portion. As a result, for example, even when external light from the rear of the moving body is incident on the optical element, the external light transmitted through the optical element is reflected by the first mirror and transmitted through the optical element again. It will be greatly attenuated by the polarization action of the optical element. As a result, it is possible to suppress the reflection of external light on the first mirror.

For example, the optical reflecting unit is further arranged so as to face the display surface of the display element, and is arranged on an optical path between the display surface of the display element and the first mirror. It may be configured to have a mirror.

According to this aspect, since the optical reflecting unit has the second mirror, the light emitted from the display surface of the display element is reflected by the optical reflecting unit a plurality of times, and then passes through the optical element and is incident on the user's eye. do. As a result, it is possible to secure the optical path length until the light emitted from the display surface of the display element is reflected by the first mirror, and the viewing distance from the eyes of the user (driver) to the display position of the virtual image of the image can be obtained. Can be extended.

For example, the second mirror is arranged to face the optical element, the polarizing element is a reflective polarizing plate, and the light emitted from the display surface of the display element is the second mirror. Reflected toward the optical element, reflected by the optical element toward the first mirror, reflected by the first mirror toward the optical element, transmitted through the optical element, and transmitted to the user's eyes. It may be configured to be incident on.

According to this aspect, the light emitted from the display surface of the display element is (i) reflected by the second mirror, (ii) reflected by the optical element, (iii) reflected by the first mirror, and then optical. It penetrates the element and enters the user's eyes. As a result, it is possible to secure an optical path length until the light emitted from the display surface of the display element is reflected by the first mirror, and it is possible to extend the viewing distance from the user's eyes to the display position of the virtual image of the image. ..

For example, the optical element is arranged over the incident portion and the emitting portion of the optical reflecting portion, and the light emitted from the display surface of the display element passes through the optical element and the second It may be configured to face the mirror and be reflected by the second mirror.

According to this aspect, since the optical element is arranged over the incident portion and the emitted portion of the optical reflecting portion, when unnecessary light that does not contribute to the display of the image is incident on the optical element, the unnecessary light is emitted. It can be blocked by the polarizing element of the optical element.

For example, the optical reflecting portion further has a half mirror arranged in the incident portion and arranged between the display element and the second mirror, and the light emitted from the display surface of the display element. Is transmitted through the half mirror, directed toward the second mirror, reflected by the second mirror toward the half mirror, reflected by the half mirror toward the optical element, and reflected by the optical element. Then, it may be configured to face the first mirror, reflect by the first mirror, face the optical element, pass through the optical element, and enter the user's eyes.

According to this aspect, the light emitted from the display surface of the display element is (i) reflected by the second mirror, (ii) reflected by the half mirror, (iii) reflected by the optical element, and (iv) th. After being reflected by the mirror of No. 1, it passes through the optical element and is incident on the user's eyes. As a result, it is possible to secure an optical path length until the light emitted from the display surface of the display element is reflected by the first mirror, and it is possible to extend the viewing distance from the user's eyes to the display position of the virtual image of the image. ..

For example, the optical reflection unit further has a half mirror arranged between the first mirror and the second mirror, and the light emitted from the display surface of the display element is the second mirror. Reflected by the mirror, toward the half mirror, transmitted through the half mirror toward the first mirror, reflected by the first mirror toward the half mirror, reflected by the half mirror, and reflected by the half mirror. It may be configured to face the optical element, pass through the optical element, and enter the user's eyes.

According to this aspect, the light emitted from the display surface of the display element is (i) reflected by the second mirror, (ii) reflected by the first mirror, (iii) reflected by the half mirror, and then optical. It penetrates the element and enters the user's eyes. As a result, it is possible to secure an optical path length until the light emitted from the display surface of the display element is reflected by the first mirror, and it is possible to extend the viewing distance from the user's eyes to the display position of the virtual image of the image. ..

For example, the optical element is arranged between the display element and the first mirror, and light emitted from the display surface of the display element passes through the optical element and faces the first mirror. , Reflected by the first mirror toward the optical element, reflected by the optical element toward the first mirror, reflected again by the first mirror toward the optical element, and directed toward the optical element. It may be configured to pass through and enter the user's eyes.

According to this aspect, the light emitted from the display surface of the display element is (i) reflected by the first mirror, (ii) reflected by the optical element, (iii) reflected again by the first mirror, and then reflected. It passes through the optical element and is incident on the user's eyes. As a result, it is possible to secure an optical path length until the light emitted from the display surface of the display element is reflected by the first mirror, and it is possible to extend the viewing distance from the user's eyes to the display position of the virtual image of the image. ..

For example, the moving body has a storage portion, the display element and the incident portion of the optical reflection portion are housed in the storage portion, and the emission portion of the optical reflection portion is exposed to the outside of the storage portion. It may be configured as it is.

According to this aspect, the incident portion of the display element and the optical reflection portion is housed in the storage portion of the moving body. As a result, it is possible to prevent the light emitted from the display surface of the display element from leaking to the outside of the optical reflection unit.

For example, a near-infrared reflecting portion that reflects near-infrared light and transmits visible light may be arranged in the emitting portion of the optical reflecting portion.

According to this aspect, for example, even when the external light from the rear of the moving body is incident on the emitting portion of the optical reflecting portion, the near infrared rays contained in the external light can be blocked by the near infrared reflecting portion. It is possible to suppress the temperature rise of the display surface of the display element due to near infrared rays and the temperature rise in the vicinity of the focal point of the first mirror.

For example, the optical reflecting portion further has an opening arranged in the incident portion, and covers the housing for accommodating the first mirror and the optical element inside, and the opening of the housing. It may be configured to have a translucent cover arranged so as to have.

According to this aspect, since the translucent cover is arranged so as to cover the opening of the housing, it is possible to prevent dust and the like from entering the inside of the housing through the opening.

For example, the display element and the first mirror may be arranged so as to be inclined with respect to the traveling direction of the moving body in a top view and arranged substantially parallel to each other.

According to this aspect, since the optical path lengths from the display element to the first mirror can be made substantially equal regardless of the position of the display surface, it is possible to realize a high-quality display system in which image distortion is suppressed. can.

For example, the optical element may be further configured to have a liquid crystal optical element for switching from one of a transmission mode for transmitting incident light and a reflection mode for reflecting incident light to the other.

According to this aspect, for example, it is possible to easily switch between an electronic mirror mode in which the rear of the moving body is confirmed by an image and an optical mirror mode in which the rear of the moving body is confirmed by optical reflection.

For example, the display system further includes a holding member that is arranged on the moving body and holds the display element and the optical reflection unit to maintain a positional relationship between the display element and the optical reflection unit. It may be configured as follows.

According to this aspect, the display system can be unitized by the holding member. As a result, it is possible to inspect the optical performance of the display system even before the display system is mounted on the mobile body (for example, at the time of shipment from the factory).

For example, the display surface of the display element emits a first linearly polarized light representing the image, the first mirror is arranged to face the display surface of the display element, and the polarizing element is arranged. A reflective polarizing plate arranged between the display element and the first mirror, transmitting the first linear polarization and reflecting the second linear polarization having a polarization direction different from that of the first linear polarization. The retardation plate is arranged between the reflective polarizing plate and the first mirror, and the first linearly polarized light emitted from the display surface of the display element is (a) the reflection. It passes through the type polarizing plate and heads toward the retardation plate, (b) is converted into first circular polarization by the retardation plate and directed toward the first mirror, and (c) is reflected by the first mirror. (D) Converted to the second linear polarization by the retardation plate and directed toward the reflective polarizing plate, and (e) reflected by the reflective polarizing plate to the retardation plate. (F) The retardation plate converts the polarization into a second circular polarization having a polarization direction different from that of the first circular polarization toward the first mirror, and (g) again with the first mirror. It may be configured to be reflected and incident on the user's eyes.

According to this aspect, the light emitted from the display surface of the display element is (i) reflected by the first mirror, (ii) reflected by the reflective polarizing plate, and (iii) reflected again by the first mirror. Later, it will be incident on the user's eyes. That is, the light emitted from the display surface of the display element enters the user's eyes after making at least two round trips between the reflective polarizing plate and the first mirror. As a result, when the optical path length until the light emitted from the display surface of the display element is reflected again by the first mirror via the reflective polarizing plate is set to a predetermined length, each component (display element). , Reflective polarizing plate, retardation plate and first mirror) can be kept short. As a result, the display system can be miniaturized while ensuring the viewing distance.

For example, the second circularly polarized light reflected again by the first mirror is further (h) directed toward the retardation plate, and (i) is converted into the first linear polarization by the retardation plate. It may be configured to face the reflective polarizing plate and (j) pass through the reflective polarizing plate and enter the user's eyes.

According to this aspect, the light reflected again by the first mirror passes through the reflective polarizing plate and then enters the user's eyes. As a result, only the first linearly polarized light reflected again by the first mirror passes through the reflective polarizing plate, and unnecessary light other than the first linearly polarized light (including external light such as sunlight) is reflected. It is blocked by a polarizing plate. As a result, the display accuracy of the image can be improved.

For example, the display system is further arranged on the opposite side of the display element from the first mirror, includes a frame having an opening, and the second circle reflected again by the first mirror. The polarization may be configured to enter the user's eye through the opening.

According to this aspect, since at least a part of the first mirror is visible to the user in front of the peripheral edge of the opening, the user can feel a sense of depth in the displayed image.

For example, the size of the opening may be configured so that the entire width of the first mirror in a predetermined direction can be visually recognized by the user.

According to this aspect, the size of the first mirror can be reduced.

For example, the display system further includes a housing that houses the display element, the reflective polarizing plate, the retardation plate, and the first mirror, and the frame is the user of the housing. It may be configured to form the side surface facing the surface.

According to this aspect, each component of the display system (display element, reflective polarizing plate, retardation plate, and first mirror) can be compactly housed inside the housing.

For example, the display system may be further configured to include a light-shielding member arranged between the display element and the opening.

According to this aspect, most of the light emitted from the display surface of the display element (hereinafter referred to as “display light”) passes through the reflective polarizing plate, but a part of the light emitted from the display surface of the display element (hereinafter referred to as “display light”). Hereinafter, "surface reflected light") is reflected by a reflective polarizing plate. Since the light-shielding member is arranged between the display element and the opening, it is possible to suppress the surface reflected light from reaching the opening. As a result, it is possible to suppress reflection on the image displayed on the display surface of the display element due to the surface reflected light being superimposed on the display light.

For example, the polarization direction of the first linear polarization and the polarization direction of the second linear polarization may be configured to be orthogonal to each other.

According to this aspect, the intensity of the display light can be increased.

For example, the retardation plate may be a λ / 4 plate, and the slow axis of the λ / 4 plate may be configured to be inclined by 45 ° with respect to the reflection axis of the reflective polarizing plate.

According to this aspect, the intensity of the display light can be increased.

For example, the first mirror and the reflective polarizing plate may be configured to be arranged non-parallel to each other.

According to this aspect, it is possible to avoid multiple reflections of light between the first mirror and the reflective polarizing plate.

For example, the first mirror may be configured to be a concave mirror or a Fresnel mirror.

According to this aspect, the degree of freedom in designing the focal position of the first mirror can be increased, and the size of the first mirror can be reduced.

For example, the reflective polarizing plate may be configured to be formed in a cylindrical shape.

According to this aspect, the size of the reflective polarizing plate can be reduced.

For example, the display system further includes a transmissive polarizing plate that is arranged between the display element and the reflective polarizing plate, transmits the first linearly polarized light, and absorbs the second linearly polarized light. It may be configured as follows.

According to this embodiment, since the transmissive polarizing plate is arranged between the display element and the reflective polarizing plate, the unnecessary light that does not contribute to the display of the image is incident on the transmissive polarizing plate. Can be absorbed by a transmissive polarizing plate. As a result, it is possible to suppress reflection on the image displayed on the display surface of the display element.

For example, the transmissive polarizing plate covers a region of the surface of the reflective polarizing plate facing the display element to which the first linearly polarized light emitted from the display surface of the display element is incident. It may be configured to be arranged in.

According to this aspect, it is possible to suppress a part of the light emitted from the display surface of the display element from being reflected by the reflective polarizing plate. As a result, it is possible to suppress reflection in the rear image displayed on the display surface of the display element.

For example, on a straight line connecting the center of the display surface of the display element and the center of the reflection surface of the first mirror, the distance between the display element and the reflective polarizing plate is set between the retardation plate and the first. It may be configured to be shorter than the distance to the mirror of 1.

According to this aspect, it is possible to secure a longer optical path length until the light emitted from the display surface of the display element is reflected again by the first mirror via the reflective polarizing plate.

For example, the first mirror has a first reflection region where the first circularly polarized light from the retardation plate is reflected and a second reflection where the second circularly polarized light from the retardation plate is reflected. It has a region, and a part of the first reflection region may be configured to overlap a part of the second reflection region.

According to this aspect, the size of the first mirror can be reduced.

For example, the display system further includes a second mirror arranged to face the surface of the reflective polarizing plate on the side facing the display element, and the first mirror transmitted through the reflective polarizing plate. The linearly polarized light may be further configured to (k) be directed toward the second mirror and (l) be reflected by the second mirror and enter the user's eyes.

According to this aspect, the display system can be made thinner by arranging the display system so that the reciprocating reflection of light between the reflective polarizing plate and the first mirror is, for example, in the vertical direction. , The user's view can be secured.

For example, the display system may be further configured to include a translucent substrate laminated between the reflective polarizing plate and the retardation plate.

According to this aspect, when each of the reflective polarizing plate and the retardation plate is formed in the form of a film, color unevenness (moire) due to the direct superposition of the reflective polarizing plate and the retardation plate. Can be suppressed.

For example, the display surface of the display element may be configured to be in contact with the surface of the reflective polarizing plate on the side facing the display element.

According to this aspect, the display system can be miniaturized.

For example, the first mirror is a concave mirror, and when the display system is viewed from the side, a normal vector passing through the center of the first mirror reflection surface is the center of the display surface of the display element. It is arranged so as to face the center side of the display surface with respect to the half-angle vector that bisects the angle formed by connecting the center of the reflection surface of the first mirror and the user's eye.

According to this aspect, a part of the light emitted from the display surface of the display element and reflected only once by the first mirror passes through the optical element and travels toward the display surface of the display element. As a result, it is possible to suppress the light reflected only once by the first mirror from reaching the user's eyes, and it is possible to suppress the reflection on the image displayed on the display surface of the display element.

Hereinafter, embodiments will be specifically described with reference to the drawings.

It should be noted that all of the embodiments described below show comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, the order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present disclosure. Further, among the components in the following embodiments, the components not described in the independent claim indicating the highest level concept are described as arbitrary components.

(Embodiment 1)
[1-1. Display system overview]
First, the outline of the display system 2 according to the first embodiment will be described with reference to FIG. FIG. 1 is a diagram showing an example of a vehicle 4 equipped with the display system 2 according to the first embodiment.

In the following description, the forward direction of the vehicle 4 is referred to as "forward", and the backward direction of the vehicle 4 is referred to as "rear". In FIG. 1, the front-rear direction of the vehicle 4 is the X-axis direction, the left-right direction of the vehicle 4 is the Y-axis direction, and the vertical direction (vertical direction) of the vehicle 4 is the Z-axis direction. Further, in FIG. 1, "front" is the minus side of the X axis, "rear" is the plus side of the X axis, "upper" is the plus side of the Z axis, and "lower" is the minus side of the Z axis.

As shown in FIG. 1, the display system 2 is mounted on, for example, an overhead console 6 (an example of a storage unit) of a vehicle 4. As a result, the display system 2 is arranged at a position where the driver 10 (an example of the user) seated in the driver's seat 8 is in the line of sight of the driver 10 with the driver 10 (an example of the user) facing forward.

The vehicle 4 is, for example, an ordinary passenger car, a vehicle such as a bus or a truck. A camera (not shown) for photographing the rear of the vehicle 4 is mounted on the rear bumper, the trunk hood, or the like of the vehicle 4. In this embodiment, the case where the display system 2 is mounted on the vehicle 4 as a mobile body will be described, but the present invention is not limited to this, and the display system 2 is mounted on various mobile bodies such as construction machinery, agricultural machinery, ships, and aircraft. May be done.

In the present embodiment, the display system 2 is a so-called electronic mirror for displaying a rear image (an example of an image) taken by a camera. The driver 10 can confirm the rear of the vehicle 4 reflected in the rear image by looking at the rear image displayed on the display system 2. That is, the display system 2 is used as a substitute for a conventional physical rear-view mirror that reflects the rear of the vehicle 4 by utilizing the reflection of light.

[1-2. Display system configuration]
Next, the configuration of the display system 2 according to the first embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a cross-sectional view of the display system 2 according to the first embodiment. FIG. 3 is a diagram showing the positional relationship of the display element 12, the concave mirror 26, and the optical element 28 of the display system 2 according to the first embodiment in a top view.

As shown in FIG. 2, the display system 2 includes a display element 12 and an optical reflection unit 14. The optical reflection unit 14 is arranged on the front side of the vehicle 4 with respect to the display element 12.

The display element 12 is, for example, a liquid crystal display (LCD: Liquid Crystal Display), and has a display surface 16 for displaying a rear image taken by a camera of the vehicle 4. The display element 12 is housed in a recess 18 formed in the overhead console 6 and is fixed to the overhead console 6. The display element 12 is arranged so that the display surface 16 faces the front of the vehicle 4. The display surface 16 is formed in a horizontally long rectangular shape, and emits light for forming a rear image. The light emitted from the display surface 16 is the first linearly polarized light having the first polarization direction d1 (the direction perpendicular to the paper surface in FIG. 2 and the Y-axis direction).

Further, a retardation plate 20 is arranged on the outermost surface of the display surface 16 of the display element 12. The retardation plate 20 is a λ / 4 plate for converting the linearly polarized light incident on the retardation plate 20 into circular polarization and converting the circularly polarized light incident on the retardation plate 20 into linearly polarized light. The slow axis of the retardation plate 20 is inclined by 45 ° with respect to the transmission axis (described later) of the transmission type reflector 52 (an example of a polarizing element). As a result, the retardation plate 20 has a function of causing a phase difference of 1/4 of the wavelength λ (that is, a phase difference of 90 °) between linearly polarized lights orthogonal to each other in the light incident on the retardation plate 20. Has. In the present embodiment, the retardation plate 20 is arranged on the outermost surface of the display surface 16 of the display element 12, but instead of such a configuration, the retardation plate 20 is mounted on the dustproof cover 24 (described later). It may be arranged.

The optical reflection unit 14 includes a housing 22, a dustproof cover 24 (an example of a translucent cover), a concave mirror 26 (an example of a first mirror), and an optical element 28. The concave mirror 26 and the optical element 28 are arranged separately from the display element 12. Further, the optical reflection unit 14 includes an incident unit 30 into which the light emitted from the display surface 16 of the display element 12 is incident, and an emitting unit 34 in which the light incident on the incident unit 30 is emitted toward the eyes 32 of the driver 10. And have.

The housing 22 is made of, for example, synthetic resin or the like, and has a storage space 36 inside. The concave mirror 26 and the optical element 28 are housed in the storage space 36 of the housing 22. The housing 22 is rotatably supported by the overhead console 6 via a ball joint 38. By rotating the housing 22 with respect to the ball joint 38, the posture of the housing 22 with respect to the overhead console 6 can be changed.

An opening 40 communicating with the storage space 36 is formed on the side surface of the display element 12 of the housing 22 on the side facing the display surface 16. The opening 40 is arranged in the incident portion 30 of the optical reflection portion 14, and is housed in the recess 18 of the overhead console 6. The opening 40 is formed in a horizontally long rectangular shape. Further, an opening 42 communicating with the storage space 36 is formed on the side surface of the housing 22 on the side facing the driver 10. The opening 42 is arranged in the exit portion 34 of the optical reflection portion 14 and is exposed to the outside of the recess 18 of the overhead console 6. The opening 42 is formed in a horizontally long rectangular shape.

The dustproof cover 24 is arranged so as to cover the opening 40 of the housing 22. That is, the dustproof cover 24 is arranged at the incident portion 30 of the optical reflection portion 14. The dustproof cover 24 is made of a translucent material such as transparent resin or glass. As a result, it is possible to prevent external dust and the like from entering the storage space 36 of the housing 22 through the opening 40.

The concave mirror 26 is arranged so as to face the dustproof cover 24, and is arranged on the front side of the vehicle 4 with respect to the display element 12 and the optical element 28. That is, the concave mirror 26 is arranged so as to face the display surface 16 of the display element 12. The concave mirror 26 has a concave reflecting surface 44 which is a free curved surface. The concave mirror 26 is formed by depositing a reflective metal film such as aluminum on the surface of a resin-molded member, for example. The concave mirror 26 is arranged so that the reflecting surface 44 faces the retardation plate 46 (described later) of the optical element 28, that is, faces the rear of the vehicle 4.

In the XY top view shown in FIG. 3, the display element 12 and the concave mirror 26 are arranged so as to be inclined with respect to the front-rear direction (X-axis direction) of the vehicle 4, and are arranged substantially parallel to each other. Specifically, in the XY side view shown in FIG. 3, the tangent line at the center of the reflection surface 44 of the concave mirror 26 and the tangent line at the center of the display surface 16 of the display element 12 are substantially parallel to each other. As used herein, "substantially parallel" not only means that they are completely parallel, but when they are substantially parallel, for example, in the rotation range of the housing 22, the display element 12 and the concave mirror 26 Is defined as "nearly parallel". As a result, the optical path lengths from the display element 12 to the concave mirror 26 can be made substantially equal regardless of the position of the display surface 16, so that image distortion is suppressed and high image quality is possible. Further, in the XY top view shown in FIG. 3, the display element 12, the concave mirror 26, and the optical element 28 may be arranged symmetrically as long as the display element 12 and the concave mirror 26 are substantially parallel to each other. It may be arranged asymmetrically.

The optical element 28 is arranged so as to cover the opening 42 of the housing 22, and is arranged so as to face the reflection surface 44 of the concave mirror 26. That is, the optical element 28 is arranged in the emission unit 34 of the optical reflection unit 14. The optical element 28 has a retardation plate 46, a glass substrate 48, a transmissive polarizing plate 52, and a retardation plate 54. In addition, in this specification, a "board" is a concept including not only a board but also a member such as a film or a sheet.

The optical element 28 is formed in a rectangular flat plate shape as a whole. The optical element 28 is configured by laminating a retardation plate 46, a glass substrate 48, a transmissive polarizing plate 52, and a retardation plate 54 in this order from the side closer to the concave mirror 26. The optical element 28 is arranged so as to be inclined with respect to the vertical direction so that the surface on the side facing the driver 10 faces diagonally downward.

The glass substrate 48 is a substrate for supporting the retardation plate 46, the transmissive polarizing plate 52, and the retardation plate 54, and is made of a translucent material, for example, transparent glass. A retardation plate 46 is superposed on the surface of the glass substrate 48 on the side facing the reflection surface 44 of the concave mirror 26. Further, a transmissive polarizing plate 52 and a retardation plate 54 are superposed on the surface of the glass substrate 48 on the side facing the driver 10.

The retardation plate 46 is a λ / 4 plate for converting the linear polarization incident on the retardation plate 46 into circular polarization and converting the circular polarization incident on the retardation plate 46 into linear polarization. The slow axis of the retardation plate 46 is tilted by 45 ° with respect to the transmission axis of the transmission type polarizing plate 52. As a result, the retardation plate 46 has a function of causing a phase difference of 1/4 of the wavelength λ between the linearly polarized lights orthogonal to each other among the light incident on the retardation plate 46.

The transmissive polarizing plate 52 absorbs the first linearly polarized light having the first polarization direction d1 among the light incident on the transmissive polarizing plate 52, and the second polarization direction d2 (in-paper direction in FIG. 2). It transmits a second linearly polarized light having a direction in the XZ plane). That is, the absorption axis of the transmissive polarizing plate 52 is in the same direction as the first polarization direction d1, and the transmission axis of the transmissive polarizing plate is in the same direction as the second polarization direction d2, and both are orthogonal to each other. In addition, in this specification, "orthogonal" not only means that they intersect at a perfect right angle, but also means that they intersect at a substantially right angle, for example, including an error of about several °.

The retardation plate 54 is a λ / 4 plate for converting the linear polarization incident on the retardation plate 54 into circular polarization and converting the circular polarization incident on the retardation plate 54 into linear polarization. The slow axis of the retardation plate 54 is tilted by 45 ° with respect to the transmission axis of the transmission type polarizing plate 52. As a result, the retardation plate 54 has a function of causing a phase difference of 1/4 of the wavelength λ between the linearly polarized lights orthogonal to each other among the light incident on the retardation plate 54.

[1-3. Display system operation]
Next, the operation of the display system 2 according to the first embodiment will be described with reference to FIGS. 1, 2, and 4. FIG. 4 is a schematic diagram for explaining the operation of the display system 2 according to the first embodiment. Note that FIG. 4 schematically illustrates the arrangement and shape of each component of the display system 2.

As shown in FIG. 4, the first linear polarization from the display surface 16 of the display element 12 is the retardation plate 20.
Incident to. The first linearly polarized light incident on the retardation plate 20 is converted into the first clockwise circular polarization by the retardation plate 20 and emitted. The first circularly polarized light emitted from the retardation plate 20 passes through the dustproof cover 24, heads toward the concave mirror 26, and is reflected by the reflecting surface 44 of the concave mirror 26.

The first circularly polarized light reflected by the reflecting surface 44 of the concave mirror 26 is directed to the retardation plate 46 of the optical element 28. The first circularly polarized light transmitted through the retardation plate 46 is converted into the second linear polarization by the retardation plate 46. The second linearly polarized light emitted from the retardation plate 46 passes through the glass substrate 48 and is incident on the transmissive polarizing plate 52. At this time, the second polarization direction d2 of the second linearly polarized light incident on the transmissive polarizing plate 52 is the same direction as the transmission axis of the transmissive polarizing plate 52. Therefore, the second linearly polarized light incident on the transmissive polarizing plate 52 is transmitted through the transmissive polarizing plate 52.

The second linear polarization transmitted through the transmissive polarizing plate 52 is incident on the retardation plate 54, and is converted by the retardation plate 54 into a counterclockwise second circular polarization having a polarization direction different from that of the first circular polarization. To. As shown in FIG. 2, the second circularly polarized light emitted from the retardation plate 54 is incident on the eyes 32 of the driver 10.

As described above, the light emitted from the display surface 16 of the display element 12 is reflected by the reflection surface 44 of the concave mirror 26, then passes through the optical element 28 and is incident on the eyes 32 of the driver 10.

By seeing the rear image reflected by the reflective surface 44 of the concave mirror 26, the driver 10 sees the rear image at the display position in front of the vehicle 4 from the display system 2 as shown in FIG. It seems that the virtual image 56 of is displayed. As a result, the amount of eye focus adjustment when the driver 10 shifts his / her line of sight to the virtual image 56 of the rear image while looking at the front of the vehicle 4 through the windshield 58 (windshield) is relatively small.

[1-4. effect]
In the present embodiment, the optical element 28 has a transmissive polarizing plate 52 and the like, and is arranged in the emission unit 34 of the optical reflection unit 14. As a result, as shown in FIG. 2, when external light from the rear of the vehicle 4 (for example, the headlight of the following vehicle or sunlight) is incident from the side of the optical element 28 from which the second circularly polarized light is emitted. Even so, approximately half of the external light is absorbed by the transmissive polarizing plate 52 of the optical element 28. Further, the external light transmitted through the optical element 28 becomes linearly polarized light (second polarization direction), is converted into circularly polarized light by the retardation plate 46, and is reflected by the reflecting surface 44 of the concave mirror 26. A part of the external light reflected by the reflecting surface 44 of the concave mirror 26 is reflected by the surface of the optical element 28 facing the concave mirror 26. Further, the remaining part of the external light reflected by the reflecting surface 44 of the concave mirror 26 is transmitted through the optical element 28 again, and at that time, linearly polarized light (first polarization direction) is performed by the retardation plate 46 of the optical element 28. ). Since the transmissive polarizing plate 52 of the optical element 28 absorbs linearly polarized light in the first polarization direction, external light is significantly attenuated. As a result, it is possible to suppress the reflection of external light on the concave mirror 26.

In this way, the external light that has passed through the optical element 28 and entered the inside of the housing 22 is significantly attenuated when it reaches the optical element 28 again even if it is reflected by the concave mirror 26. Therefore, the possibility that the external light is collected by the concave mirror 26 is greatly suppressed. As a result, it is possible to suppress the generation of a high temperature portion caused by the light collection in the concave mirror 26 of the external light.

Further, the incident portion 30 of the display element 12 and the optical reflection portion 14 is housed in the recess 18 of the overhead console 6. As a result, it is possible to prevent the light emitted from the display surface 16 of the display element 12 from leaking to the outside of the optical reflection unit 14.

Further, since the retardation plate 54 is arranged on the outermost surface of the optical element 28, the light emitted from the optical element 28 becomes second circularly polarized light by the retardation plate 54 and is incident on the eyes 32 of the driver 10. do. This allows, for example, even when the driver 10 is wearing polarized sunglasses or the like.
The light transmitted through the retardation plate 54 can be incident on the eyes 32 of the driver 10.

A film-shaped near-infrared reflecting unit that reflects near-infrared light and transmits visible light may be arranged in the emitting unit 34 of the optical reflecting unit 14. In this case, the near-infrared reflecting portion is arranged so as to cover the surface of the optical element 28 on the side facing the driver 10. As a result, even when the external light from the rear of the vehicle 4 is incident on the optical element 28, the near-infrared rays contained in the external light can be blocked by the near-infrared reflecting unit, which is caused by the near-infrared rays. It is possible to suppress the temperature rise of the display surface 16 of the display element 12 and the temperature rise in the vicinity of the focal point of the concave mirror 26.

(Embodiment 2)
[2-1. Display system configuration]
The configuration of the display system 2A according to the second embodiment will be described with reference to FIG. FIG. 5 is a cross-sectional view of the display system 2A according to the second embodiment. In each of the following embodiments, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 5, in the display system 2A according to the second embodiment, the configuration of the housing 22A of the optical reflection unit 14A, that is, the positional relationship between the opening 40 and the opening 42 of the housing 22A is the above-mentioned embodiment. It is different from Form 1. Specifically, in the XZ side view, in the first embodiment, the angle between the dustproof cover 24 and the optical element 28 is an acute angle, whereas in the present embodiment, the dustproof cover 24 and the optical element 28 are formed at an acute angle. The angle formed by the element 28A is an acute angle.

Further, in the display system 2A according to the second embodiment, the configuration of the optical element 28A is different from that of the first embodiment. Specifically, the optical element 28A has a retardation plate 46, a glass substrate 48, a reflective polarizing plate 50 (an example of a polarizing element), and a retardation plate 54. Does not have the transmissive polarizing plate 52 (see FIG. 2) described in the above. The optical element 28A is configured by laminating a retardation plate 46, a glass substrate 48, a reflective polarizing plate 50, and a retardation plate 54 in this order from the side closer to the concave mirror 26.

The reflective polarizing plate 50 reflects the first linearly polarized light having the first polarization direction d1 among the light incident on the reflective polarizing plate 50, and is orthogonal to the first polarization direction d1. It transmits a second linearly polarized light having a second polarization direction d2. That is, the reflection axis of the reflective polarizing plate 50 is in the same direction as the first polarization direction d1 and the transmission axis is in the second polarization direction d2, and both are orthogonal to each other.

The stacking order of each component of the optical element 28A is not limited to this, and the optical element 28A has, for example, a retardation plate 46, a reflective polarizing plate 50, a glass substrate 48, and a retardation plate 54 on a concave mirror 26. It may be configured by laminating each other in this order from the closest side.

[2-2. Display system operation]
Next, the operation of the display system 2A according to the second embodiment will be described with reference to FIG.

In the display system 2A according to the second embodiment, since the optical element 28A does not have the transmissive polarizing plate, the electronic mirror mode for confirming the rear of the vehicle 4 (see FIG. 1) with a rear image and the rear of the vehicle 4 It is possible to switch between the optical mirror mode and the optical mirror mode, which confirms the image by optical reflection. When the display system 2A is configured so as not to switch between the electronic mirror mode and the optical mirror mode, the optical element 28A is the reflective polarizing plate 50, similarly to the optical element 28 described in the first embodiment. Instead of this, a transmission type polarizing plate 52 (see FIG. 2) may be provided.

In the electronic mirror mode, the display of the rear image on the display element 12 is turned on. Further, as shown in FIG. 5, the driver 10 rotates the housing 22A with respect to the ball joint 38 so that the surface of the optical element 28A facing the driver 10 faces diagonally upward. (That is, the direction of the housing 22A is adjusted so that the ceiling of the vehicle 4 is reflected in the optical element 28A). As a result, it is possible to suppress the reflection of external light on the optical element 28A. In the electronic mirror mode, the path of the light emitted from the display surface 16 of the display element 12 is the same as that of the first embodiment, and thus the description thereof will be omitted.

On the other hand, in the optical mirror mode, the display of the rear image on the display element 12 is turned off. Further, although not shown, the driver 10 rotates the housing 22A with respect to the ball joint 38 so that the surface of the optical element 28A facing the driver 10 faces the rear of the vehicle 4. Adjust the orientation of the housing 22A. External light (light representing the rear of the vehicle 4) from the rear of the vehicle 4 is reflected by the reflective polarizing plate 50 of the optical element 28A. As a result, the optical element 28A functions as a physical optical mirror.

[2-3. effect]
In the present embodiment, the driver 10 can switch the display system 2A to either the electronic mirror mode or the optical mirror mode according to the driving situation of the vehicle 4 and the like. Further, since the angle formed by the dustproof cover 24 and the optical element 28A in the XZ side view is an obtuse angle, the amount of rotation of the housing 22A can be small when switching from one of the electronic mirror mode and the optical mirror mode to the other. ..

[2-4. Modification example]
Instead of the above-mentioned optical element 28A, a liquid crystal mirror 60 as shown in FIG. 6 may be used as the optical element. FIG. 6 is a cross-sectional view of the liquid crystal mirror 60 according to the modified example of the second embodiment.

As shown in FIG. 6, the liquid crystal mirror 60 includes a retardation plate 46, a reflective polarizing plate 50, a glass substrate 48a, a TN (Twisted Nematic) liquid crystal 62 (an example of a liquid crystal optical element), a glass substrate 48b, and a transmissive polarizing plate. 52 is configured by laminating in this order.

In the electronic mirror mode, the liquid crystal mirror 60 is switched to the transmission mode in which the incident light is transmitted by turning on the voltage application to the TN liquid crystal 62. The first circularly polarized light reflected by the reflecting surface 44 of the concave mirror 26 (see FIG. 5) is directed to the retardation plate 46 of the liquid crystal mirror 60. The first circularly polarized light transmitted through the retardation plate 46 is converted into the second linear polarization by the retardation plate 46. The second linearly polarized light emitted from the retardation plate 46 is incident on the reflective polarizing plate 50. At this time, the second polarization direction d2 of the second linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the transmission axis of the reflective polarizing plate 50. Therefore, the second linearly polarized light incident on the reflective polarizing plate 50 passes through the reflective polarizing plate 50.

The second linearly polarized light transmitted through the reflective polarizing plate 50 passes through the glass substrate 48a and is incident on the TN liquid crystal display 62, and is transmitted through the TN liquid crystal display 62 as the second linearly polarized light. The second linearly polarized light transmitted through the TN liquid crystal 62 passes through the glass substrate 48b and is incident on the transmissive polarizing plate 52. At this time, the second polarization direction d2 of the second linearly polarized light incident on the transmissive polarizing plate 52 is the same direction as the transmission axis of the transmissive polarizing plate 52. Therefore, the second linearly polarized light incident on the transmissive polarizing plate 52 is transmitted through the transmissive polarizing plate 52.

On the other hand, in the optical mirror mode, the liquid crystal mirror 60 is switched to the reflection mode for reflecting the incident light by turning off the voltage application to the TN liquid crystal 62. External light (light representing the rear of the vehicle 4) from the rear of the vehicle 4 enters the transmissive polarizing plate 52 and is converted into second linear polarization when passing through the transmissive polarizing plate 52. The second linearly polarized light emitted from the transmissive polarizing plate 52 passes through the glass substrate 48b, enters the TN liquid crystal display 62, and is converted into the first linearly polarized light when passing through the TN liquid crystal display 62. The first linearly polarized light emitted from the TN liquid crystal 62 passes through the glass substrate 48a and is incident on the reflective polarizing plate 50. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the reflection axis of the reflective polarizing plate 50. Therefore, the first linearly polarized light incident on the reflective polarizing plate 50 is reflected by the reflective polarizing plate 50.

The first linearly polarized light reflected by the reflective polarizing plate 50 passes through the glass substrate 48a and is incident on the TN liquid crystal display 62, and is converted into the second linearly polarized light when passing through the TN liquid crystal display 62. The second linearly polarized light emitted from the TN liquid crystal 62 passes through the glass substrate 48b, enters the transmissive polarizing plate 52, and transmits the transmissive polarizing plate 52.

As described above, by using the liquid crystal mirror 60 as a half mirror, it is possible to easily switch between the electronic mirror mode and the optical mirror mode, and it is possible to suppress reflection in the electronic mirror mode. In addition, the contrast of the rear image can be improved.

(Embodiment 3)
[3-1. Display system configuration]
The configuration of the display system 2B according to the third embodiment will be described with reference to FIGS. 7 and 8. FIG. 7 is a cross-sectional view of the display system 2B according to the third embodiment in the electronic mirror mode. FIG. 8 is a cross-sectional view of the display system 2B according to the third embodiment in the optical mirror mode.

As shown in FIGS. 7 and 8, in the display system 2B according to the third embodiment, the optical reflection unit 14B includes a housing 22B, a dustproof cover 24, a concave mirror 26, an optical element 28A, and a flat mirror. It has 64 (an example of a second mirror). The dustproof cover 24 is arranged so that the surface facing the display element 12 faces diagonally upward. As a result, reflection on the dustproof cover 24 can be suppressed.

The planar mirror 64 has a planar reflecting surface 66. The flat mirror 64 is formed by depositing a reflective metal film such as aluminum on the surface of a resin-molded member, for example. The flat mirror 64 is arranged on an optical path between the display surface 16 of the display element 12 and the concave mirror 26. Specifically, the plane mirror 64 is arranged so that the reflecting surface 66 faces each of the display surface 16 of the display element 12 and the retardation plate 46 of the optical element 28A. In the present embodiment, the optical reflection unit 14B has a flat mirror 64, but instead of the flat mirror 64, a concave mirror different from the concave mirror 26 may be used.

Further, in the present embodiment, the shape of the housing 22B is different from that of the first embodiment because the optical reflection unit 14B has the plane mirror 64.

Further, in the present embodiment, the configuration of the optical element 28A is basically the same as that of the second embodiment. However, in the present embodiment, it is assumed that the transmission axis of the reflective polarizing plate 50 is in the same direction as the first polarization direction d1 and the reflection axis is in the same direction as the second polarization direction d2, and both are orthogonal to each other. ..

[3-2. Display system operation]
Next, the operation of the display system 2B according to the third embodiment will be described with reference to FIGS. 7 to 9. FIG. 9 is a schematic diagram for explaining the operation of the display system 2B according to the third embodiment. Note that FIG. 9 schematically illustrates the arrangement and shape of each component of the display system 2B.

In the display system 2B according to the third embodiment, the electronic mirror mode and the optical mirror mode can be switched as in the second embodiment.

As shown in FIG. 7, in the electronic mirror mode, the display of the rear image on the display element 12 is turned on. Further, the driver 10 rotates the housing 22B with respect to the ball joint 38 so that the surface of the optical element 28A facing the driver 10 faces diagonally downward. Adjust.

As shown in FIG. 9, the first linear polarization from the display surface 16 of the display element 12 is incident on the retardation plate 20. The first linearly polarized light transmitted through the retardation plate 20 is converted into a clockwise first circular polarization by the retardation plate 20. The first circularly polarized light emitted from the retardation plate 20 passes through the dustproof cover 24, heads toward the flat mirror 64, and is reflected by the reflecting surface 66 of the flat mirror 64.

The first circularly polarized light reflected by the reflecting surface 66 of the plane mirror 64 is directed to the retardation plate 46 of the optical element 28A. The first circularly polarized light transmitted through the retardation plate 46 is converted into the second linear polarization by the retardation plate 46. The second linearly polarized light emitted from the retardation plate 46 passes through the glass substrate 48 and is incident on the reflective polarizing plate 50. At this time, the second polarization direction d2 of the second linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the reflection axis of the reflective polarizing plate 50. Therefore, the second linearly polarized light incident on the reflective polarizing plate 50 is reflected by the reflective polarizing plate 50.

The second linearly polarized light reflected by the reflective polarizing plate 50 passes through the glass substrate 48 and is incident on the retardation plate 46. The second linearly polarized light transmitted through the retardation plate 46 is converted into a counterclockwise second circular polarization by the retardation plate 46. The second circularly polarized light emitted from the retardation plate 46 is directed toward the concave mirror 26 and reflected by the reflecting surface 44 of the concave mirror 26.

The second circularly polarized light reflected by the reflecting surface 44 of the concave mirror 26 is directed to the retardation plate 46 of the optical element 28A. The second circularly polarized light transmitted through the retardation plate 46 is converted into the first linear polarization by the retardation plate 46. The first linearly polarized light emitted from the retardation plate 46 passes through the glass substrate 48 and is incident on the reflective polarizing plate 50. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the transmission axis of the reflective polarizing plate 50. Therefore, the first linearly polarized light incident on the reflective polarizing plate 50 passes through the reflective polarizing plate 50.

The first linearly polarized light transmitted through the reflective polarizing plate 50 is converted into the first circularly polarized light by the retardation plate 54. As shown in FIG. 7, the first circularly polarized light emitted from the retardation plate 54 is incident on the eyes 32 of the driver 10.

On the other hand, as shown in FIG. 8, in the optical mirror mode, the display of the rear image on the display element 12 is turned off. Further, the driver 10 rotates the housing 22B with respect to the ball joint 38 so that the surface of the optical element 28A facing the driver 10 faces the rear of the vehicle 4 (see FIG. 1). , Adjust the orientation of the housing 22B. External light (light representing the rear of the vehicle 4) from the rear of the vehicle 4 is reflected by the reflective polarizing plate 50 of the optical element 28A.

[3-3. effect]
The viewing distance from the driver 10's eyes 32 to the display position of the virtual image 56 (see FIG. 1) of the rear image is until the light emitted from the display surface 16 of the display element 12 is reflected by the reflection surface 44 of the concave mirror 26. Determined by the optical path length.

Therefore, in the present embodiment, in the electronic mirror mode, the light emitted from the display surface 16 of the display element 12 is reflected by (i) the reflection surface 66 of the plane mirror 64, and (ii) the optical element 28.
After being reflected by the reflective polarizing plate 50 of A and reflected by the reflecting surface 44 of the concave mirror 26 (iii), it passes through the optical element 28A and is incident on the eyes 32 of the driver 10.

As a result, the optical path length until the light emitted from the display surface 16 of the display element 12 is reflected by the reflection surface 44 of the concave mirror 26 can be secured, and the viewing distance can be extended.

(Embodiment 4)
[4-1. Display system configuration]
The configuration of the display system 2C according to the fourth embodiment will be described with reference to FIGS. 10 and 11. FIG. 10 is a cross-sectional view of the display system 2C according to the fourth embodiment in the electronic mirror mode. FIG. 11 is a cross-sectional view of the display system 2C according to the fourth embodiment in the optical mirror mode.

As shown in FIGS. 10 and 11, in the display system 2C according to the fourth embodiment, the optical reflection unit 14C has a housing 22C, a concave mirror 26, an optical element 28C, and a flat mirror 64. It does not have the dustproof cover 24 described in the first embodiment.

An opening 68 communicating with the storage space 36 is formed on the side surface of the housing 22C on the side facing each of the display element 12 and the driver 10. The opening 68 of the housing 22C is arranged over the incident portion 30 and the emitting portion 34 of the optical reflecting portion 14C.

The optical element 28C is arranged so as to cover the opening 68 of the housing 22C, and is arranged so as to face each of the reflecting surface 44 of the concave mirror 26 and the reflecting surface 66 of the flat mirror 64. That is, the optical element 28C is arranged over the incident portion 30 and the emitting portion 34 of the optical reflecting portion 14C.

The optical element 28C includes a retardation plate 46, a glass substrate 48, a reflective polarizing plate 50, and a retardation plate 54C. The optical element 28C is configured by laminating a retardation plate 46, a glass substrate 48, a reflective polarizing plate 50, and a retardation plate 54C in this order from the side closer to the concave mirror 26 and the planar mirror 64. The stacking order of each component of the optical element 28C is not limited to this, and the optical element 28C includes, for example, a retardation plate 46, a reflective polarizing plate 50, a glass substrate 48, and a retardation plate 54C, a concave mirror 26, and a retardation plate 54C. It may be configured by laminating each other in this order from the side closest to the plane mirror 64.

Further, in the present embodiment, it is assumed that the transmission axis of the reflective polarizing plate 50 is in the same direction as the first polarization direction d1 and the reflection axis is in the same direction as the second polarization direction d2, and both are orthogonal to each other. .. The retardation plate 54C is arranged only in the emitting portion 34 of the optical reflecting portion 14C, and is not arranged in the incident portion 30 of the optical reflecting portion 14C. That is, on the surface of the optical reflection unit 14C facing the driver 10, a reflection type polarizing plate 50 is arranged on the incident portion 30 of the optical reflection unit 14C, and a retardation plate is arranged on the emission portion 34 of the optical reflection unit 14C. 54C is arranged.

Further, in the present embodiment, the retardation plate 20 (see FIG. 2) described in the first embodiment is not arranged on the display surface 16 of the display element 12.

[4-2. Display system operation]
Next, the operation of the display system 2C according to the fourth embodiment will be described with reference to FIGS. 10 and 11.

In the display system 2C according to the fourth embodiment, the electronic mirror mode and the optical mirror mode can be switched as in the second embodiment.

As shown in FIG. 10, in the electronic mirror mode, the display of the rear image on the display element 12 is turned on. Further, the driver 10 rotates the housing 22C with respect to the ball joint 38 so that the surface of the optical element 28C facing the driver 10 faces diagonally downward. Adjust.

As shown in FIG. 10, the first linear polarization from the display surface 16 of the display element 12 is incident on the incident portion 30 of the optical reflection unit 14C, that is, the reflective polarizing plate 50 of the optical element 28C. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the transmission axis of the reflective polarizing plate 50. Therefore, the first linearly polarized light incident on the reflective polarizing plate 50 passes through the reflective polarizing plate 50. The first linearly polarized light transmitted through the reflective polarizing plate 50 passes through the glass substrate 48 and is incident on the retardation plate 46.

The first linearly polarized light transmitted through the retardation plate 46 is converted into a clockwise first circular polarization by the retardation plate 46. The first circularly polarized light emitted from the retardation plate 46 is directed toward the planar mirror 64 and reflected by the reflecting surface 66 of the planar mirror 64.

The first circularly polarized light reflected by the reflecting surface 66 of the plane mirror 64 is directed to the retardation plate 46 of the optical element 28C. The first circularly polarized light transmitted through the retardation plate 46 is converted into the second linear polarization by the retardation plate 46. The second linearly polarized light emitted from the retardation plate 46 passes through the glass substrate 48 and is incident on the reflective polarizing plate 50. At this time, the second polarization direction d2 of the second linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the reflection axis of the reflective polarizing plate 50. Therefore, the second linearly polarized light incident on the reflective polarizing plate 50 is reflected by the reflective polarizing plate 50.

The second linearly polarized light reflected by the reflective polarizing plate 50 passes through the glass substrate 48 and is incident on the retardation plate 46. The second linearly polarized light transmitted through the retardation plate 46 is converted into a counterclockwise second circular polarization by the retardation plate 46. The second circularly polarized light emitted from the retardation plate 46 is directed toward the concave mirror 26 and reflected by the reflecting surface 44 of the concave mirror 26.

The second circularly polarized light reflected by the reflecting surface 44 of the concave mirror 26 is directed to the retardation plate 46 of the optical element 28C. The second circularly polarized light transmitted through the retardation plate 46 is converted into the first linear polarization by the retardation plate 46. The first linearly polarized light emitted from the retardation plate 46 passes through the glass substrate 48 and is incident on the reflective polarizing plate 50. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the transmission axis of the reflective polarizing plate 50. Therefore, the first linearly polarized light incident on the reflective polarizing plate 50 passes through the reflective polarizing plate 50.

The first linearly polarized light transmitted through the reflective polarizing plate 50 is incident on the retardation plate 54C. The first linear polarization transmitted through the retardation plate 54C is converted into the first circular polarization by the retardation plate 54C. The first circularly polarized light emitted from the emission unit 34 of the optical reflection unit 14C, that is, the retardation plate 54C, is incident on the eyes 32 of the driver 10.

On the other hand, as shown in FIG. 11, in the optical mirror mode, the display of the rear image on the display element 12 is turned off. Further, the driver 10 rotates the housing 22C with respect to the ball joint 38 so that the surface of the optical element 28C facing the driver 10 faces the rear of the vehicle 4 (see FIG. 1). , Adjust the orientation of the housing 22C. External light (light representing the rear of the vehicle 4) from the rear of the vehicle 4 is reflected by the reflective polarizing plate 50 of the optical element 28C.

[4-3. effect]
In the present embodiment, in the electronic mirror mode, the light emitted from the display surface 16 of the display element 12 is reflected by (i) the reflection surface 66 of the plane mirror 64, and (ii) the reflective polarizing plate 50 of the optical element 28C. (Iii) After being reflected by the reflecting surface 44 of the concave mirror 26, it passes through the optical element 28C and is incident on the eyes 32 of the driver 10.

As a result, the optical path length until the light emitted from the display surface 16 of the display element 12 is reflected by the reflection surface 44 of the concave mirror 26 can be secured, and the viewing distance can be extended.

(Embodiment 5)
[5-1. Display system configuration]
The configuration of the display system 2D according to the fifth embodiment will be described with reference to FIG. FIG. 12 is a cross-sectional view of the display system 2D according to the fifth embodiment.

As shown in FIG. 12, in the display system 2D according to the fifth embodiment, the optical reflection unit 14D includes a housing 22D, a concave mirror 26, an optical element 28, a flat mirror 64, and a half mirror 70. However, it does not have the dustproof cover 24 described in the first embodiment.

The half mirror 70 is arranged so as to cover the opening 40 of the housing 22D, and is arranged between the display element 12 and the flat mirror 64. That is, the half mirror 70 is arranged at the incident portion 30 of the optical reflection portion 14D. The half mirror 70 has a retardation plate 72, a glass substrate 74, and a reflective polarizing plate 76. The half mirror 70 is configured by stacking a retardation plate 72, a glass substrate 74, and a reflective polarizing plate 76 in this order from the side closest to the planar mirror 64. The stacking order of each component of the half mirror 70 is not limited to this, and the half mirror 70 has, for example, a retardation plate 72, a reflective polarizing plate 76, and a glass substrate 74 in this order from the side closer to the flat mirror 64. It may be configured by stacking each other.

The retardation plate 72, the glass substrate 74, and the reflective polarizing plate 76 of the half mirror 70 have the same functions as the retardation plate 46, the glass substrate 48, and the reflective polarizing plate 50 of the optical element 28, respectively. In the present embodiment, the transmission axis of the reflection type polarizing plate 76 of the half mirror 70 is the same direction as the first polarization direction d1 and the reflection axis is the same direction as the second polarization direction d2, and both are orthogonal to each other. And.

Further, in the present embodiment, the reflection axis of the reflective polarizing plate 50 of the optical element 28 is in the same direction as the first polarization direction d1 and the transmission axis is in the same direction as the second polarization direction d2, and both are orthogonal to each other. It is assumed that there is.

Further, in the present embodiment, the retardation plate 20 (see FIG. 2) described in the first embodiment is not arranged on the display surface 16 of the display element 12.

[5-2. Display system operation]
Next, the operation of the display system 2D according to the fifth embodiment will be described with reference to FIG.

As shown in FIG. 12, the first linear polarization from the display surface 16 of the display element 12 is incident on the reflective polarizing plate 76 of the half mirror 70. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 76 is the same direction as the transmission axis of the reflective polarizing plate 76. Therefore, the first linearly polarized light incident on the reflective polarizing plate 76 passes through the reflective polarizing plate 76. The first linearly polarized light transmitted through the reflective polarizing plate 76 passes through the glass substrate 74 and is incident on the retardation plate 72.

The first linearly polarized light transmitted through the retardation plate 72 is converted into the first clockwise circular polarization by the retardation plate 72. The first circularly polarized light emitted from the retardation plate 72 is directed to the planar mirror 64 and reflected by the reflecting surface 66 of the planar mirror 64.

The first circular polarization reflected by the reflecting surface 66 of the plane mirror 64 is directed to the retardation plate 72 of the half mirror 70. The first circularly polarized light transmitted through the retardation plate 72 is converted into the second linear polarization by the retardation plate 72. The second linearly polarized light emitted from the retardation plate 72 passes through the glass substrate 74 and is incident on the reflective polarizing plate 76. At this time, the second polarization direction d2 of the second linearly polarized light incident on the reflective polarizing plate 76 is the same direction as the reflection axis of the reflective polarizing plate 76. Therefore, the second linearly polarized light incident on the reflective polarizing plate 76 is reflected by the reflective polarizing plate 76.

The second linearly polarized light reflected by the reflective polarizing plate 76 passes through the glass substrate 74 and is incident on the retardation plate 72. The second linearly polarized light transmitted through the retardation plate 72 is converted into a counterclockwise second circular polarization by the retardation plate 72. The second circularly polarized light emitted from the retardation plate 72 is directed to the retardation plate 46 of the optical element 28.

The second circularly polarized light transmitted through the retardation plate 46 is converted into the first linear polarization by the retardation plate 46. The first linearly polarized light emitted from the retardation plate 46 passes through the glass substrate 48 and is incident on the reflective polarizing plate 50. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the reflection axis of the reflective polarizing plate 50. Therefore, the first linearly polarized light incident on the reflective polarizing plate 50 is reflected by the reflective polarizing plate 50.

The first linearly polarized light reflected by the reflective polarizing plate 50 passes through the glass substrate 48 and is incident on the retardation plate 46. The second linear polarization transmitted through the retardation plate 46 is converted into the first circular polarization by the retardation plate 46. The first circularly polarized light transmitted through the retardation plate 46 is directed toward the concave mirror 26 and is reflected by the reflecting surface 44 of the concave mirror 26.

The first circularly polarized light reflected by the reflecting surface 44 of the concave mirror 26 is directed to the retardation plate 46 of the optical element 28. The first circularly polarized light transmitted through the retardation plate 46 is converted into the second linear polarization by the retardation plate 46. The second linearly polarized light emitted from the retardation plate 46 passes through the glass substrate 48 and is incident on the reflective polarizing plate 50. At this time, the second polarization direction d2 of the second linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the transmission axis of the reflective polarizing plate 50. Therefore, the second linearly polarized light incident on the reflective polarizing plate 50 passes through the reflective polarizing plate 50.

The second linearly polarized light transmitted through the reflective polarizing plate 50 is incident on the transmissive polarizing plate 52. At this time, the second polarization direction d2 of the second linearly polarized light incident on the transmissive polarizing plate 52 is the same direction as the transmission axis of the transmissive polarizing plate 52. Therefore, the second linearly polarized light incident on the transmissive polarizing plate 52 is transmitted through the transmissive polarizing plate 52.

The second linearly polarized light transmitted through the transmissive polarizing plate 52 is incident on the retardation plate 54 and converted into the second circular polarization by the retardation plate 54. The second circularly polarized light emitted from the retardation plate 54 is incident on the eyes 32 of the driver 10.

[5-3. effect]
In the present embodiment, the light emitted from the display surface 16 of the display element 12 is (i) reflected by the reflecting surface 66 of the plane mirror 64, and (ii) reflected by the reflective polarizing plate 76 of the half mirror 70. iii) Reflected by the reflective polarizing plate 50 of the optical element 28, (iv) reflected by the reflecting surface 44 of the concave mirror 26, and then transmitted through the optical element 28 and incident on the eyes 32 of the driver 10.

As a result, the optical path length until the light emitted from the display surface 16 of the display element 12 is reflected by the reflection surface 44 of the concave mirror 26 can be secured, and the viewing distance can be extended.

(Embodiment 6)
[6-1. Display system configuration]
The configuration of the display system 2E according to the sixth embodiment will be described with reference to FIGS. 13 to 15. FIG. 13 is a cross-sectional view of the display system 2E according to the sixth embodiment in the electronic mirror mode. FIG. 14 is a cross-sectional view of the display system 2E according to the sixth embodiment in the optical mirror mode. FIG. 15 is a front view showing the concave mirror 26, the optical element 28A, and the half mirror 78 of the display system 2E according to the sixth embodiment.

As shown in FIGS. 13 and 14, in the display system 2E according to the sixth embodiment, the optical reflection unit 14E includes a housing 22E, a dustproof cover 24, a concave mirror 26, an optical element 28A, and a flat mirror. It has 64 and a half mirror 78.

The half mirror 78 is arranged between the flat mirror 64 and the concave mirror 26 in the storage space 36 of the housing 22E. The half mirror 78 has a reflective polarizing plate 80, a glass substrate 82, and a retardation plate 84. The half mirror 78 is configured by stacking a reflective polarizing plate 80, a glass substrate 82, and a retardation plate 84 on each other in this order from the side closest to the plane mirror 64. The stacking order of each component of the half mirror 78 is not limited to this, and the half mirror 78 has, for example, a glass substrate 82, a reflective polarizing plate 80, and a retardation plate 84 in this order from the side closer to the planar mirror 64. It may be configured by stacking each other. The reflective polarizing plate 80, the glass substrate 82, and the retardation plate 84 of the half mirror 78 have the same functions as the reflective polarizing plate 50, the glass substrate 48, and the retardation plate 46 of the optical element 28, respectively. In the present embodiment, the transmission axis of the reflection type polarizing plate 80 of the half mirror 78 is the same direction as the first polarization direction d1 and the reflection axis is the same direction as the second polarization direction d2, and both are orthogonal to each other. And.

Further, in the present embodiment, the transmission axis of the reflective polarizing plate 50 of the optical element 28A is in the same direction as the first polarization direction d1 and the reflection axis is in the same direction as the second polarization direction d2, and both are orthogonal to each other. It is assumed that there is.

Further, as shown in FIG. 15, the concave mirror 26 is arranged so that the reflecting surface 44 faces upward of the vehicle 4 (see FIG. 1). The lower end portions (end portions on the concave mirror 26 side) of each of the optical element 28A and the half mirror 78 are formed into a convexly curved shape corresponding to the shape of the concave mirror 26 on the reflection surface 44 side. The upper end portions (end portions on the plane mirror 64 side) of each of the optical element 28A and the half mirror 78 are linearly formed. As a result, the lower ends of each of the optical element 28A and the half mirror 78 can be arranged close to the reflecting surface 44 of the concave mirror 26, and the housing 22E can be miniaturized.

Further, in the present embodiment, the retardation plate 20 (see FIG. 2) described in the first embodiment is not arranged on the display surface 16 of the display element 12.

[6-2. Display system operation]
Next, the operation of the display system 2E according to the sixth embodiment will be described with reference to FIGS. 13 and 14.

In the display system 2E according to the sixth embodiment, the electronic mirror mode and the optical mirror mode can be switched as in the second embodiment.

As shown in FIG. 13, in the electronic mirror mode, the display of the rear image on the display element 12 is turned on. Further, the driver 10 rotates the housing 22E with respect to the ball joint 38 so that the surface of the optical element 28A facing the driver 10 faces diagonally upward (that is, the ceiling of the vehicle 4). Is reflected in the optical element 28A), and the orientation of the housing 22E is adjusted. As a result, it is possible to suppress the reflection of external light on the optical element 28A. Further, when switching from the electronic mirror mode to the optical mirror mode as described later, the amount of rotation of the housing 22E can be small.

As shown in FIG. 13, the first linear polarization from the display surface 16 of the display element 12 passes through the dustproof cover 24, heads toward the plane mirror 64, and is reflected by the reflection surface 66 of the plane mirror 64.

The first linearly polarized light reflected by the reflecting surface 66 of the plane mirror 64 faces the reflective polarizing plate 80 of the half mirror 78 and is incident on the reflective polarizing plate 80. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 80 is the same direction as the transmission axis of the reflective polarizing plate 80. Therefore, the first linearly polarized light incident on the reflective polarizing plate 80 passes through the reflective polarizing plate 80.

The first linearly polarized light transmitted through the reflective polarizing plate 80 passes through the glass substrate 82 and is incident on the retardation plate 84. The first linear polarization transmitted through the retardation plate 84 is converted into the first circular polarization by the retardation plate 84. The first circularly polarized light emitted from the retardation plate 84 is directed toward the concave mirror 26 and reflected by the reflecting surface 44 of the concave mirror 26.

The first circular polarization reflected by the reflecting surface 44 of the concave mirror 26 is directed toward the retardation plate 84 of the half mirror 78. The first circularly polarized light transmitted through the retardation plate 84 is converted into the second linear polarization by the retardation plate 84. The second linearly polarized light emitted from the retardation plate 84 passes through the glass substrate 82 and is incident on the reflective polarizing plate 80. At this time, the second polarization direction d2 of the second linearly polarized light incident on the reflective polarizing plate 80 is the same direction as the reflection axis of the reflective polarizing plate 80. Therefore, the second linearly polarized light incident on the reflective polarizing plate 80 is reflected by the reflective polarizing plate 80.

The second linearly polarized light reflected by the reflective polarizing plate 80 passes through the glass substrate 82 and is incident on the retardation plate 84. The second linear polarization transmitted through the retardation plate 84 is converted into the second circular polarization by the retardation plate 84. The second circularly polarized light emitted from the retardation plate 84 is directed to the retardation plate 46 of the optical element 28A.

The second circularly polarized light transmitted through the retardation plate 46 is converted into the first linear polarization by the retardation plate 46. The first linearly polarized light emitted from the retardation plate 46 passes through the glass substrate 48 and is incident on the reflective polarizing plate 50. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the transmission axis of the reflective polarizing plate 50. Therefore, the first linearly polarized light incident on the reflective polarizing plate 50 passes through the reflective polarizing plate 50.

The first linearly polarized light transmitted through the reflective polarizing plate 50 is converted into the first circularly polarized light by the retardation plate 54. The first circularly polarized light emitted from the retardation plate 54 is incident on the eyes 32 of the driver 10.

On the other hand, as shown in FIG. 14, in the optical mirror mode, the display of the rear image on the display element 12 is turned off. Further, the driver 10 rotates the housing 22E with respect to the ball joint 38 so that the surface of the optical element 28A facing the driver 10 faces the rear of the vehicle 4. Adjust the orientation. The external light from the rear of the vehicle 4 is reflected by the reflective polarizing plate 50 of the optical element 28A.

[6-3. effect]
In the present embodiment, the light emitted from the display surface 16 of the display element 12 is (i) reflected by the reflection surface 66 of the flat mirror 64, (ii) reflected by the reflection surface 44 of the concave mirror 26, and (iii). After being reflected by the reflective polarizing plate 80 of the half mirror 78, it passes through the optical element 28A and is incident on the eyes 32 of the driver 10.

As a result, the optical path length until the light emitted from the display surface 16 of the display element 12 is reflected by the reflection surface 44 of the concave mirror 26 can be secured, and the viewing distance can be extended.

[6-4. Modification example]
The configuration of the display system 2F according to the modified example of the sixth embodiment will be described with reference to FIG. FIG. 16 is a cross-sectional view of the display system 2F according to the modified example of the sixth embodiment in the electronic mirror mode.

As shown in FIG. 16, in the display system 2F according to the modified example of the sixth embodiment, the position of the opening 40 of the housing 22F of the optical reflection unit 14F and the position of the plane mirror 64 are reversed. Along with this, the display element 12 is arranged on the front side of the vehicle 4 with respect to the optical reflection unit 14F. Even with such a configuration, the above-mentioned effect can be obtained.

(Embodiment 7)
[7-1. Display system configuration]
The configuration of the display system 2G according to the seventh embodiment will be described with reference to FIGS. 17 and 18. FIG. 17 is a cross-sectional view of the display system 2G according to the seventh embodiment in the electronic mirror mode. FIG. 18 is a cross-sectional view of the display system 2G according to the seventh embodiment in the optical mirror mode.

As shown in FIGS. 17 and 18, in the display system 2G according to the seventh embodiment, the optical reflection unit 14G includes a housing 22G, a dustproof cover 24, a concave mirror 26, and an optical element 28G. ing.

An opening 86 that communicates with the storage space 36 is formed on the side surface of the housing 22G on the side facing each of the display element 12 and the driver 10. The opening 86 of the housing 22G is arranged over the incident portion 30 and the emitting portion 34 of the optical reflecting portion 14G. The dustproof cover 24 is arranged so as to cover the opening 86 of the housing 22G.

The optical element 28G is arranged between the dustproof cover 24 and the concave mirror 26 in the storage space 36 of the housing 22G. The optical element 28G has a retardation plate 46, a glass substrate 48, and a reflective polarizing plate 50. The optical element 28G is configured by laminating a retardation plate 46, a glass substrate 48, and a reflective polarizing plate 50 on each other in this order from the side closer to the concave mirror 26. The stacking order of each component of the optical element 28G is not limited to this, and the optical element 28G has, for example, a retardation plate 46, a reflective polarizing plate 50, and a glass substrate 48 in this order from the side closer to the concave mirror 26. It may be configured by laminating each other. Further, in the present embodiment, the optical element 28G is formed in a flat plate shape, but the present invention is not limited to this, and the optical element 28G may be formed in a cylindrical shape, for example.

The reflective polarizing plate 50 is arranged so as to face the dustproof cover 24. That is, the reflective polarizing plate 50 is arranged over the incident portion 30 and the emitted portion 34 of the optical reflecting portion 14G. In the present embodiment, it is assumed that the transmission axis of the reflective polarizing plate 50 is in the same direction as the first polarization direction d1 and the reflection axis is in the same direction as the second polarization direction d2, and both are orthogonal to each other.

Further, between the display element 12 and the dustproof cover 24, a light-shielding member 88 that covers the opening of the recess 18 of the overhead console 6 is arranged. The light-shielding member 88 is made of a material having a light-shielding property, and is formed, for example, in the shape of a horizontally long flat plate long in the left-right direction.

Further, in the present embodiment, the retardation plate 20 (see FIG. 2) described in the first embodiment is not arranged on the display surface 16 of the display element 12.

[7-2. Display system operation]
Next, the operation of the display system 2G according to the seventh embodiment will be described with reference to FIGS. 17 and 18.

In the display system 2G according to the seventh embodiment, the electronic mirror mode and the optical mirror mode can be switched as in the second embodiment.

As shown in FIG. 17, in the electronic mirror mode, the display of the rear image on the display element 12 is turned on. Further, the driver 10 rotates the housing 22G with respect to the ball joint 38 so that the surface of the dustproof cover 24 facing the driver 10 faces diagonally upward. To adjust.

As shown in FIG. 17, the first linearly polarized light from the display surface 16 of the display element 12 passes through the dustproof cover 24 and is incident on the reflective polarizing plate 50 of the optical element 28G. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the transmission axis of the reflective polarizing plate 50. Therefore, the first linearly polarized light incident on the reflective polarizing plate 50 passes through the reflective polarizing plate 50.

The first linearly polarized light transmitted through the reflective polarizing plate 50 passes through the glass substrate 48 and is incident on the retardation plate 46. The first linearly polarized light transmitted through the retardation plate 46 is converted into a clockwise first circular polarization by the retardation plate 46. The first circularly polarized light emitted from the retardation plate 46 is directed toward the concave mirror 26 and reflected by the reflecting surface 44 of the concave mirror 26.

The first circularly polarized light reflected by the reflecting surface 44 of the concave mirror 26 is directed to the retardation plate 46 of the optical element 28G. The first circularly polarized light transmitted through the retardation plate 46 is converted into the second linear polarization by the retardation plate 46. The second linearly polarized light emitted from the retardation plate 46 passes through the glass substrate 48 and is incident on the reflective polarizing plate 50. At this time, the second polarization direction d2 of the second linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the reflection axis of the reflective polarizing plate 50. Therefore, the second linearly polarized light incident on the reflective polarizing plate 50 is reflected by the reflective polarizing plate 50.

The second linearly polarized light reflected by the reflective polarizing plate 50 passes through the glass substrate 48 and is incident on the retardation plate 46. The second linearly polarized light transmitted through the retardation plate 46 is converted into a counterclockwise second circular polarization by the retardation plate 46. The second circularly polarized light emitted from the retardation plate 46 is directed toward the concave mirror 26 and reflected by the reflecting surface 44 of the concave mirror 26.

The second circularly polarized light reflected by the reflecting surface 44 of the concave mirror 26 is directed to the retardation plate 46 of the optical element 28G. The second circularly polarized light transmitted through the retardation plate 46 is converted into the first linear polarization by the retardation plate 46. The first linearly polarized light emitted from the retardation plate 46 passes through the glass substrate 48 and is incident on the reflective polarizing plate 50. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 50 is the same direction as the transmission axis of the reflective polarizing plate 50. Therefore, the first linearly polarized light incident on the reflective polarizing plate 50 passes through the reflective polarizing plate 50. The first linearly polarized light transmitted through the reflective polarizing plate 50 passes through the dustproof cover 24 and is incident on the eyes 32 of the driver 10.

On the other hand, as shown in FIG. 18, in the optical mirror mode, the display of the rear image on the display element 12 is turned off. Further, the driver 10 rotates the housing 22G with respect to the ball joint 38 so that the surface of the optical element 28G facing the driver 10 faces the rear of the vehicle 4 (see FIG. 1). , Adjust the orientation of the housing 22G. The external light from the rear of the vehicle 4 is reflected by the reflective polarizing plate 50 of the optical element 28G.

[7-3. effect]
In the present embodiment, the light emitted from the display surface 16 of the display element 12 is (i) reflected by the reflective surface 44 of the concave mirror 26, and (ii) reflected by the reflective polarizing plate 50 of the optical element 28G. iii) After being reflected again by the reflecting surface 44 of the concave mirror 26, it passes through the optical element 28G and is incident on the eyes 32 of the driver 10. That is, the light emitted from the display surface 16 of the display element 12 reciprocates twice between the optical element 28G and the concave mirror 26, and then enters the eyes 32 of the driver 10.

As a result, the optical path length until the light emitted from the display surface 16 of the display element 12 is reflected by the reflection surface 44 of the concave mirror 26 can be secured, and the viewing distance can be extended.

Further, since the optical reflection unit 14G has a configuration in which the concave mirror 26 and the optical element 28G are arranged so as to face each other, the size of the housing 22G in the front-rear direction can be reduced. Although the optical element 28G and the dustproof cover 24 are separate bodies in the present embodiment, the optical element 28G itself may be used as the dustproof cover as in the fourth embodiment. Further, as in the fourth embodiment, the retardation plate 34 (see FIG. 10) may be arranged only in the emission region of the optical element 28G.

[7-4. Modification example]
The configuration of the display system 2H according to the modified example of the seventh embodiment will be described with reference to FIG. FIG. 19 is a cross-sectional view of the display system 2H according to the modified example of the seventh embodiment in the electronic mirror mode.

As shown in FIG. 19, in the display system 2H according to the modified example of the seventh embodiment, the display element 12 is arranged so that the display surface 16 faces the lower side of the vehicle 4. Further, a flat mirror 90 is arranged between the display element 12 and the light-shielding member 88. The planar mirror 90 has a planar reflecting surface 91. The flat mirror 90 is arranged so as to be inclined with respect to the vertical direction so that the reflecting surface 91 faces each of the display element 12 and the dustproof cover 24.

The light emitted from the display surface 16 of the display element 12 is reflected by the reflection surface 91 of the plane mirror 90 and then incident on the dustproof cover 24.

In this modification, the optical path length until the light emitted from the display surface 16 of the display element 12 is reflected by the concave mirror 26 can be secured longer, and the viewing distance can be extended more effectively.

(Embodiment 8)
[8-1. Display system configuration]
The configuration of the display system 2J according to the eighth embodiment will be described with reference to FIG. 20. FIG. 20 is a cross-sectional view of the display system 2J according to the eighth embodiment.

As shown in FIG. 20, the display system 2J according to the eighth embodiment includes a holding member 92 in addition to the components described in the first embodiment.

The holding member 92 is arranged in the recess 18 of the overhead console 6 and is a member for maintaining the positional relationship between the display element 12 and the optical reflection unit 14. The holding member 92 includes a first holding portion 92a for holding the display element 12, a second holding portion 92b for holding the optical reflecting portion 14 via the ball joint 38, and a first holding portion 92a and a second holding portion 92a. It has a connecting portion 92c that connects the holding portion 92b. As a result, the display element 12 is fixed to the overhead console 6 via the holding member 92.

[8-2. effect]
In the present embodiment, the display system 2J can be unitized by the holding member 92. This makes it possible to inspect the optical performance of the display system 2J even before the display system 2J is mounted on the vehicle 4 (see FIG. 1) (for example, at the time of shipment from a factory). The holding member 92 can also be applied to the above embodiments 2 to 7.

(Embodiment 9)
[9-1. Display system overview]
An outline of the display system 2K according to the ninth embodiment will be described with reference to FIG. 21. FIG. 21 is a diagram showing an example of a vehicle 4 equipped with the display system 2K according to the ninth embodiment.

As shown in FIG. 21, the display system 2 is attached to, for example, a portion of the windshield 58 of the vehicle 4 on the side close to the ceiling 94 via a ball joint 38. As a result, the display system 2K is arranged at a position where the driver 10 seated in the driver's seat 8 is in the line of sight of the driver 10 with the driver 10 facing forward. In this embodiment, the case where the display system 2K is attached to the windshield 58 will be described, but the present invention is not limited to this, and the display system 2K may be attached to, for example, an overhead console.

In the following description, the coordinate system is defined as follows.

First, as shown in FIG. 21, a plane having an optical path (included in the alternate long and short dash line in FIG. 21) in which light emitted from the display system 2K reaches the eyes of the driver 10 is defined as an XZ plane. Therefore, FIG. 21 corresponds to a cross section of the vehicle 4 cut along the XZ plane. Next, on the XZ plane, the vertical direction (vertical direction) of the vehicle 4 is defined as the Z-axis direction. Next, the direction perpendicular to the XZ plane is defined as the Y-axis direction. Therefore, the Y-axis direction and the X-axis direction orthogonal to the Z-axis direction are the forward direction of the vehicle 4 (hereinafter, also referred to as “forward”) and the backward direction of the vehicle 4 (hereinafter, also referred to as “rear”). The direction is slightly inclined in the Y-axis direction with respect to the straight line connecting the above. Further, in FIG. 21, the “front” side is the minus side of the X axis, the “rear” side is the plus side of the X axis, the “upper” is the plus side of the Z axis, and the “lower” side is the minus side of the Z axis.

The vehicle 4 is, for example, an ordinary passenger car, a vehicle such as a bus or a truck. A camera (not shown) for photographing the rear of the vehicle 4 is mounted on the rear bumper, the trunk hood, or the like of the vehicle 4. In the present embodiment, the case where the display system 2K is mounted on the vehicle 4 as a mobile body will be described, but the present invention is not limited to this, and the display system 2K is mounted on various moving bodies such as construction machinery, agricultural machinery, ships, and aircraft. May be done.

In the present embodiment, the display system 2K is a so-called electronic mirror for displaying a rear image (an example of an image) taken by a camera. The driver 10 can confirm the rear of the vehicle 4 reflected in the rear image by looking at the rear image displayed on the display system 2K. That is, the display system 2K is used as a substitute for a conventional physical rear-view mirror that reflects the rear of the vehicle 4 by utilizing the reflection of light.

[9-2. Display system configuration]
Next, the configuration of the display system 2K according to the ninth embodiment will be described with reference to FIGS. 21 to 23. FIG. 22 is a cross-sectional view of the display system 2K according to the ninth embodiment. Figure 2
3 is a perspective view showing the internal structure of the display system 2K according to the ninth embodiment.

As shown in FIG. 22, the display system 2K includes a housing 116, a display element 118, an optical element 120, and a mirror 122 (an example of a first mirror).

The housing 116 is made of, for example, synthetic resin or the like, and has a storage space 124 inside. The display element 118, the optical element 120, and the mirror 122 are housed in the storage space 124 of the housing 116. As shown in FIG. 21, the housing 116 is suspended from the windshield 58 of the vehicle 4 via a ball joint 38. By rotating the housing 116 with respect to the ball joint 38, the posture of the housing 116 with respect to the windshield 58 of the vehicle 4 can be changed.

An opening 126 that communicates with the storage space 124 is formed on the side surface 116a (an example of the frame) of the housing 116 on the side facing the driver 10. The opening 126 is formed in a horizontally long rectangular shape. That is, the size of the opening 126 in the left-right direction (Y-axis direction) is larger than the size in the up-down direction (Z-axis direction). As shown in FIG. 23, the size of the opening 126 is such that a part of the width of the reflecting surface 138 (described later) of the mirror 122 in the left-right direction can be visually recognized from the driver 10.

The opening 126 of the housing 116 is closed by a plate-shaped dustproof cover 128 made of, for example, transparent resin or glass. As a result, it is possible to prevent external dust and the like from entering the storage space 124 of the housing 116 through the opening 126. The dustproof cover 128 is arranged so as to be inclined with respect to the vertical direction so that the surface of the dustproof cover 128 facing the driver 10 faces diagonally upward. As a result, it is possible to suppress the reflection of external light on the dustproof cover 128.

The display element 118 is, for example, a liquid crystal display (LCD: Liquid Crystal).
Display). The display element 118 has a display surface 130 for displaying a rear image taken by the camera of the vehicle 4, and is arranged diagonally above the opening 126 of the housing 116. The display surface 130 is formed in a horizontally long rectangular shape, and is arranged so as to be inclined with respect to the vertical direction so as to face diagonally downward, for example. The display surface 130 emits light for forming a rear image. The light emitted from the display surface 130 is the first linearly polarized light having the first polarization direction d1 (the direction perpendicular to the paper surface in FIG. 22 and the Y-axis direction).

The optical element 120 is arranged between the display element 118 and the mirror 122. That is, the optical element 120 is arranged in front of the display element 118 so as to face the display surface 130 of the display element 118. The optical element 120 has a glass substrate 132 (an example of a translucent substrate), a reflective polarizing plate 134 (an example of a polarizing element), and a retardation plate 136. In addition, in this specification, a "board" is a concept including not only a board but also a member such as a film or a sheet.

The optical element 120 is formed in a flat plate shape as a whole, and is arranged at an angle with respect to the display surface 130 around an axis parallel to the above-mentioned first polarization direction d1 (around the Y axis). .. In addition, in this specification, "parallel" not only means that it is completely parallel, but also means that when it is substantially parallel, it includes an error of, for example, about several degrees. Here, the upper end portion 120a (the end portion on the plus side of the Z axis) of the optical element 120 is arranged on the side close to the mirror 122, and the lower end portion 120b (the end portion on the minus side of the Z axis) of the optical element 120 is arranged. It is arranged on the side far from the mirror 122. The optical element 120 is configured by laminating a reflective polarizing plate 134, a glass substrate 132, and a retardation plate 136 on each other in this order from the side closer to the display surface 130 of the display element 118.

The glass substrate 132 is a substrate for supporting the reflective polarizing plate 134 and the retardation plate 136, and is made of a translucent material, for example, transparent glass. A reflective polarizing plate 134 is superposed on the surface of the glass substrate 132 on the side facing the display element 118. Further, a retardation plate 136 is superposed on the surface of the glass substrate 132 on the side facing the mirror 122. That is, the glass substrate 132 is laminated between the reflective polarizing plate 134 and the retardation plate 136. As a result, when each of the reflective polarizing plate 134 and the retardation plate 136 is formed in the form of a film, the color unevenness (moire) caused by the direct superimposition of the reflective polarizing plate 134 and the retardation plate 136. ) Can be suppressed.

The reflective polarizing plate 134 transmits the first linearly polarized light having the first polarization direction d1 among the light incident on the reflective polarizing plate 134, and is orthogonal to the first polarization direction d1. It reflects the second linearly polarized light having the second polarization direction d2 (the direction in the paper surface of FIG. 22 and the direction in the XZ plane). That is, the transmission axis of the reflective polarizing plate 134 is in the same direction as the first polarization direction d1 and the reflection axis is in the second polarization direction d2, and both are orthogonal to each other. In addition, in this specification, "orthogonal" not only means that they intersect at a perfect right angle, but also means that they intersect at a substantially right angle, for example, including an error of about several °.

The retardation plate 136 is a λ / 4 plate for converting the linear polarization incident on the retardation plate 136 into circular polarization and converting the circular polarization incident on the retardation plate 136 into linear polarization. The slow axis of the retardation plate 136 is tilted by 45 ° with respect to the reflection axis of the reflective polarizing plate 134. As a result, the retardation plate 136 has a function of causing a phase difference of 1/4 of the wavelength λ (that is, a phase difference of 90 °) between the linearly polarized lights orthogonal to each other among the light incident on the retardation plate 136. Has.

The mirror 122 is arranged in front of the optical element 120 so as to face the retardation plate 136 of the optical element 120. That is, the mirror 122 is arranged so as to face the display surface 130 of the display element 118. The mirror 122 is a concave mirror and has a concave reflecting surface 38 which is a free curved surface. The mirror 122 is formed by depositing a reflective metal film such as aluminum on the surface of a resin-molded member, for example. The mirror 122 is arranged so that the reflecting surface 138 faces the retardation plate 136 of the optical element 120.

The mirror 122 and the reflective polarizing plate 134 are arranged non-parallel to each other. Specifically, in the XZ side view shown in FIG. 22, the tangent line at the center of the reflective surface 138 of the mirror 122 and the tangent line at the center of the surface of the reflective polarizing plate 134 facing the display element 118 are not mutually exclusive. It is parallel.

[9-3. Display system operation]
Next, the operation of the display system 2K according to the ninth embodiment will be described with reference to FIGS. 21, 22 and 24. FIG. 24 is a schematic diagram for explaining the operation of the display system 2K according to the ninth embodiment. Note that FIG. 24 schematically illustrates the arrangement and shape of each component of the display system 2K.

As shown in FIG. 24, the first linearly polarized light from the display surface 130 of the display element 118 is incident on the reflective polarizing plate 134 of the optical element 120. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 134 is the same direction as the transmission axis of the reflective polarizing plate 134. Therefore, the first linearly polarized light incident on the reflective polarizing plate 134 is transmitted through the reflective polarizing plate 134.

The first linearly polarized light transmitted through the reflective polarizing plate 134 passes through the glass substrate 132 and heads toward the retardation plate 136. The first linearly polarized light transmitted through the retardation plate 136 is converted into the first clockwise circular polarization by the retardation plate 136. The first circularly polarized light emitted from the retardation plate 136 is directed to the mirror 122 and reflected by the reflecting surface 138 of the mirror 122. Here, the first circular polarization emitted from the retardation plate 136 does not necessarily have to be strict circular polarization, for example, even if the elliptical polarization (= minor axis / major axis) is 70% or less. good. At this time, as will be described later, when the first circular polarization transmitted through the retardation plate 136 is converted into the second linear polarization, the amount of light loss due to the deviation from the strict linear polarization is 1/3 or less. It is desirable to have. In this case, the desired light is 66% or more, and visibility can be obtained.

The first circularly polarized light reflected by the reflecting surface 138 of the mirror 122 is directed to the retardation plate 136. The first circularly polarized light transmitted through the retardation plate 136 is converted into the second linear polarization by the retardation plate 136. The second linearly polarized light emitted from the retardation plate 136 passes through the glass substrate 132 and is incident on the reflective polarizing plate 134. At this time, the second polarization direction d2 of the second linearly polarized light incident on the reflective polarizing plate 134 is the same direction as the reflection axis of the reflective polarizing plate 134. Therefore, the second linearly polarized light incident on the reflective polarizing plate 134 is reflected by the reflective polarizing plate 134.

The second linearly polarized light reflected by the reflective polarizing plate 134 passes through the glass substrate 132 and heads toward the retardation plate 136. The second linear polarization transmitted through the retardation plate 136 is converted by the retardation plate 136 into a counterclockwise second circular polarization having a polarization direction different from that of the first circular polarization. The second circularly polarized light emitted from the retardation plate 136 is directed to the mirror 122 and reflected by the reflecting surface 138 of the mirror 122.

As shown in FIG. 22, the second circularly polarized light reflected by the reflecting surface 138 of the mirror 122 goes toward the dust-proof cover 128 without passing through the optical element 120, and passes through the dust-proof cover 128 (that is, an opening). It is incident on the eye 32 of the driver 10 (via the unit 126).

As described above, the light emitted from the display surface 130 of the display element 118 is (i) reflected by the reflection surface 138 of the mirror 122, (ii) reflected by the reflective polarizing plate 134, and (iii) the mirror 122. After being reflected again by the reflecting surface 138, it is incident on the eyes of the driver 10. That is, the light emitted from the display surface 130 of the display element 118 makes two round trips between the reflective polarizing plate 134 and the mirror 122, and then enters the eyes of the driver 10.

By seeing the rear image reflected by the reflection surface 138 of the mirror 122 by the driver 114, as shown in FIG. 21, the driver 10 sees the rear image at the display position in front of the vehicle 4 with respect to the display system 2K. The virtual image 56 appears to be displayed. As a result, the amount of eye focus adjustment when the driver 10 shifts his / her line of sight to the virtual image 56 of the rear image while looking at the front of the vehicle 4 through the windshield 58 is relatively small.

As shown in FIG. 24, the reflection surface 138 of the mirror 122 has a first reflection region 144 to which the first circular polarization from the retardation plate 136 is reflected and a second circular polarization from the retardation plate 136. Has a second reflection area 146 to reflect. The first reflection region 144 is arranged closer to the upper side of the reflection surface 138, and the second reflection region 146 is arranged closer to the lower side of the reflection surface 138. At this time, a part (lower end portion) of the first reflection region 144 overlaps with a part (upper end portion) of the second reflection region 146. As a result, the size of the mirror 122 in the vertical direction can be made compact.

[9-4. effect]
Hereinafter, by comparing the display system 2K according to the ninth embodiment with the display system 200 according to the comparative example with reference to FIG. 25, the effect obtained by the display system 2K according to the ninth embodiment will be described. FIG. 25 is a diagram for comparing the display system 2K according to the ninth embodiment and the display system 200 according to the comparative example.

As shown in FIG. 25 (a), the display system 200 according to the comparative example includes a housing 202, a display element 204 composed of a liquid crystal display or the like, an optical element 206, and a concave mirror 208. ..

A display element 204, an optical element 206, and a concave mirror 208 are housed inside the housing 202. A dustproof cover 212 is arranged in the opening 210 of the housing 202. The display element 204 has a display surface 214 for displaying a rear image, and a λ / 4 plate (not shown) is arranged on the outermost surface.

The optical element 206 is arranged so as to face the display surface 214 of the display element 204, and is arranged so as to be inclined with respect to the display surface 214. Although not shown, the optical element 206 is configured by superimposing a reflective polarizing plate and a λ / 4 plate on each other.

The concave mirror 208 is a concave mirror having a free curved surface, and is arranged so as to face the optical element 206.

The light emitted from the display surface 214 of the display element 204 is reflected by the optical element 206 and then incident on the concave mirror 208. The emitted light reflected by the concave mirror 208 passes through the optical element 206 and then passes through the dustproof cover 212 and is incident on the driver's eyes.

As described above, the light emitted from the display surface 214 of the display element 204 is (i) reflected by the optical element 206, reflected by (ii) the concave mirror 208, and then incident on the driver's eyes. That is, the light emitted from the display surface 214 of the display element 204 makes one round trip between the optical element 206 and the concave mirror 208, and then enters the driver's eyes.

Here, the viewing distance from the driver's eyes to the display position of the virtual image of the rear image is the optical path length until the light emitted from the display surface 214 of the display element 204 reaches the concave mirror 208 via the optical element 206. It is determined by (the distance indicated by the alternate long and short dash line in (a) of FIG. 25). Therefore, in order to secure the viewing distance, it is necessary to set the optical path length to a predetermined length, but the distance between each component (display element 204, optical element 206, and concave mirror 208) is correspondingly longer. Therefore, there arises a problem that the housing 202 becomes large.

On the other hand, as shown in FIG. 25 (b), in the display system 2K according to the ninth embodiment, the light emitted from the display surface 130 of the display element 118 is (i) the reflection surface 138 of the mirror 122. It is reflected, reflected by the (ii) reflective polarizing plate 134, and again reflected by the reflecting surface 138 of the (iii) mirror 122, and then incident on the eyes of the driver 10. That is, the light emitted from the display surface 130 of the display element 118 makes two round trips between the reflective polarizing plate 134 and the mirror 122, and then enters the eyes of the driver 10.

As a result, the optical path length (distance indicated by the alternate long and short dash line in FIG. 25B) until the light emitted from the display surface 130 of the display element 118 is reflected again by the mirror 122 via the optical element 120 is determined above. When the length is set to the above, the distance between each component (display element 118, optical element 120, and mirror 122) can be kept short, and the housing 116 can be miniaturized.

That is, the optical path length in (a) of FIG. 25 is the same as the optical path length in (b) of FIG. 25, but the size D1 in the front-rear direction of the housing 116 of the display system 2K according to the ninth embodiment. Is the size D2 in the front-rear direction of the housing 202 of the display system 200 according to the comparative example.
Is smaller than. Therefore, in the display system 2K according to the ninth embodiment, it is possible to obtain the effect that the miniaturization can be achieved while ensuring the viewing distance.

As shown in FIG. 22, the display element 118 and the reflective polarization are on a straight line (indicated by a alternate long and short dash line in FIG. 22) connecting the center of the display surface 130 of the display element 118 and the center of the reflection surface 138 of the mirror 122. The distance L1 from the plate 134 may be shorter than the distance L2 between the retardation plate 136 and the mirror 122. As a result, the above-mentioned optical path length can be secured longer. On the contrary, although not shown, the distance L1 between the display element 118 and the reflective polarizing plate 134 may be longer than the distance L2 between the retardation plate 136 and the mirror 122. As a result, when the optical element 120 and the mirror 122 are housed in one housing, the thickness of the housing can be reduced.

Further, as described above, the size of the opening 126 of the housing 116 is such that a part of the width of the reflective surface 138 of the mirror 122 in the left-right direction can be visually recognized from the driver 10. As a result, the driver 10 can see a part of the reflective surface 138 of the mirror 122 in front of the peripheral edge of the opening 126, so that the driver 10 can feel a sense of depth in the rear image.

The size of the opening 126 of the housing 116 may be such that the entire width of the reflective surface 138 of the mirror 122 in the left-right direction can be visually recognized from the driver 10. As a result, the width of the mirror 122 in the left-right direction does not need to be larger than the width of the opening 126 of the housing 116 in the left-right direction, so that the mirror 122 can be miniaturized.

Further, as described above, in the XZ side view shown in FIG. 22, the mirror 122 and the reflective polarizing plate 134 are arranged non-parallel to each other. This makes it possible to avoid multiple reflections of light between the mirror 122 and the reflective polarizing plate 134.

In the present embodiment, the arrangement of each component shown in FIG. 22 is the arrangement in the XZ side view, but the arrangement is not limited to this, and the arrangement of each component shown in FIG. 22 may be the arrangement in the XY top view. good. In this case, the display system 2K can be used, for example, as an electronic outer mirror, and the mirror 122 and the reflective polarizing plate 134 are arranged non-parallel to each other in XY top view. As a result, the arrangement of the display element 118 with respect to the mirror 122 can be shifted in the left-right direction (Y-axis direction), and the degree of freedom in the arrangement of the display element 118 can be increased. In this case, the display element 118 is arranged on, for example, a front door or an A pillar.

(Embodiment 10)
[10-1. Display system configuration]
The configuration of the display system 2L according to the tenth embodiment will be described with reference to FIG. 26. FIG. 26 is a cross-sectional view of the display system 2L according to the tenth embodiment. In each of the following embodiments, the same components as those in the ninth embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 26, in the display system 2L according to the tenth embodiment, the size of the optical element 120L is different from that of the ninth embodiment. Specifically, the optical element 120L has a size capable of covering almost all the light reflected by the reflecting surface 138 of the mirror 122. That is, the height position of the lower end portion 120b of the optical element 120L from the bottom surface of the housing 116 is lower than that of the ninth embodiment. The height position of the upper end portion 120a of the optical element 120L from the bottom surface of the housing 116 is the same as that of the ninth embodiment.

[10-2. Display system operation]
Next, the operation of the display system 2L according to the tenth embodiment will be described with reference to FIGS. 26 and 27. FIG. 27 is a schematic diagram for explaining the operation of the display system 2L according to the tenth embodiment. Note that FIG. 27 schematically illustrates the arrangement and shape of each component of the display system 2L.

As shown in FIG. 27, the light emitted from the display surface 30 of the display element 118 is reflected by (i) the reflective surface 138 of the mirror 122 and (ii) the reflective polarizing plate 134, as in the ninth embodiment. (Iii) Reflects again on the reflecting surface 138 of the mirror 122.

After that, the light (second circular polarization) reflected again by the reflecting surface 138 of the mirror 122 heads toward the retardation plate 136. The second circularly polarized light transmitted through the retardation plate 136 is converted into the first linear polarization by the retardation plate 136. The first linearly polarized light emitted from the retardation plate 136 passes through the glass substrate 132 and is incident on the reflective polarizing plate 134. At this time, the first polarization direction d1 of the first linearly polarized light incident on the reflective polarizing plate 134 is the same direction as the transmission axis of the reflective polarizing plate 134. Therefore, the first linearly polarized light incident on the reflective polarizing plate 134 is transmitted through the reflective polarizing plate 134.

As shown in FIG. 26, the first linearly polarized light transmitted through the reflective polarizing plate 134 passes through the dustproof cover 128 and is incident on the eyes 32 of the driver 10 (see FIG. 22).

[10-3. effect]
As described above, in the present embodiment, the light reflected again by the reflecting surface 138 of the mirror 122 passes through the reflective polarizing plate 134 and then is incident on the eyes 32 of the driver 10. As a result, only the first linearly polarized light reflected again by the reflecting surface 138 of the mirror 122 passes through the reflective polarizing plate 134, and unnecessary light other than the first linearly polarized light (light that does not contribute to the display of the rear image) is emitted. , It is blocked by the reflective polarizing plate 134. This unnecessary light also includes sunlight incident from the rear of the vehicle 4 (see FIG. 21) via the dustproof cover 128 of the opening 126. As a result, the display accuracy of the rear image can be improved. Further, it is possible to suppress the temperature rise caused by the sunlight condensing with the mirror 122.

(Embodiment 11)
[11-1. Display system configuration]
The configuration of the display system 2M according to the eleventh embodiment will be described with reference to FIG. 28. FIG. 28 is a cross-sectional view of the display system 2M according to the eleventh embodiment.

As shown in FIG. 28, the display system 2M according to the eleventh embodiment includes a light-shielding member 148 in addition to the configuration requirements described in the tenth embodiment. The light-shielding member 148 is made of a material having a light-shielding property, and is formed, for example, in the shape of a horizontally long flat plate long in the left-right direction. The light-shielding member 148 is housed in the storage space 124 of the housing 116, and is arranged between the display element 118 and the opening 126 of the housing 116.

[11-2. effect]
Most of the light emitted from the display surface 130 of the display element 118 (hereinafter referred to as “display light”) passes through the reflective polarizing plate 134 of the optical element 120L. Further, a part of the light emitted from the display surface 130 of the display element 118 (hereinafter referred to as “surface reflected light”) is reflected by the reflective polarizing plate 134 of the optical element 120L.

As described above, in the present embodiment, since the light-shielding member 148 is arranged between the display element 118 and the opening 126 of the housing 116, the surface reflection reflected by the reflective polarizing plate 134 of the optical element 120L It is possible to prevent the light from reaching the opening 126 of the housing 116. As a result, it is possible to suppress reflection in the rear image due to the surface reflected light being superimposed on the display light.

(Embodiment 12)
[12-1. Display system configuration]
The configuration of the display system 2N according to the twelfth embodiment will be described with reference to FIG. 29. FIG. 29 is a cross-sectional view of the display system 2N according to the twelfth embodiment.

As shown in FIG. 29, in the display system 2N according to the twelfth embodiment, the configuration of the optical element 120N is different from that of the tenth embodiment. Specifically, the optical element 120N has a transmissive polarizing plate 150 in addition to the glass substrate 132, the reflective polarizing plate 134, and the retardation plate 136. The optical element 120N is configured by laminating a transmissive polarizing plate 150, a reflective polarizing plate 134, a glass substrate 132, and a retardation plate 136 in this order from the side closer to the display surface 130 of the display element 118. That is, the transmissive polarizing plate 150 is arranged between the display element 118 and the reflective polarizing plate 134. Further, the transmissive polarizing plate 150 is arranged so as to cover the entire region of the surface of the reflective polarizing plate 134 on the side facing the display element 118.

The transmissive polarizing plate 150 transmits the first linear polarization having the first polarization direction d1 and the second linear polarization having the second polarization direction d2 among the light incident on the transmissive polarizing plate 150. To absorb. That is, the transmission axis of the transmissive polarizing plate 150 is in the same direction as the first polarization direction d1, and the absorption axis of the transmissive polarizing plate 150 is in the same direction as the second polarization direction d2, and both are orthogonal to each other.

[12-2. Display system operation]
Next, the operation of the display system 2N according to the twelfth embodiment will be described with reference to FIG. 29.

As shown in FIG. 29, the first linearly polarized light emitted from the display surface 130 of the display element 118 passes through the transmissive polarizing plate 150 and heads toward the reflective polarizing plate 134. After that, the light transmitted through the transmissive polarizing plate 150 is (i) reflected by the reflecting surface 138 of the mirror 122, reflected by (ii) the reflective polarizing plate 134, and (iii), as in the ninth embodiment. It is reflected again by the reflecting surface 138 of the mirror 122.

After that, the light (second circularly polarized light) reflected again by the reflecting surface 138 of the mirror 122 is converted into the first linearly polarized light by the retardation plate 136 in the same manner as in the above embodiment 10, and is converted to the glass substrate 132 and the reflection. It passes through the type polarizing plate 134. After that, in the present embodiment, the first linear polarization transmitted through the reflective polarizing plate 134 is transmitted through the transmissive polarizing plate 150 and directed toward the dustproof cover 128, and is transmitted through the dustproof cover 128 to the driver 10. It is incident on the eye 32 (see FIG. 22).

[12-3. effect]
In the present embodiment, since the transmissive polarizing plate 150 is arranged so as to cover the entire area of the surface of the reflective polarizing plate 134 on the side facing the display element 118, unnecessary light that does not contribute to the display of the image is generated. When incident on the transmissive polarizing plate 150, the unnecessary light can be absorbed by the transmissive polarizing plate 150. As a result, it is possible to suppress reflection on the rear image displayed on the display surface 130 of the display element 118.

(Embodiment 13)
[13-1. Display system configuration]
The configuration of the display system 2P according to the thirteenth embodiment will be described with reference to FIG. 30. FIG. 30 is a cross-sectional view of the display system 2P according to the thirteenth embodiment.

As shown in FIG. 30, in the display system 2P according to the thirteenth embodiment, the size of the transmissive polarizing plate 150P of the optical element 120P is different from that of the twelfth embodiment. Specifically, the transmissive polarizing plate 150P covers only the region where the light emitted from the display surface 130 of the display element 118 is incident on the surface of the reflective polarizing plate 134 facing the display element 118. Have been placed.

[13-2. effect]
In the present embodiment, the transmissive polarizing plate 150P covers only the region on which the light emitted from the display surface 130 of the display element 118 is incident on the surface of the reflective polarizing plate 134 facing the display element 118. Since it is arranged in, it is possible to suppress the above-mentioned surface reflected light from being reflected by the reflective polarizing plate 134. As a result, it is possible to suppress reflection on the rear image displayed on the display surface 130 of the display element 118.

(Embodiment 14)
[14-1. Display system configuration]
The configuration of the display system 2Q according to the fourteenth embodiment will be described with reference to FIG. 31. FIG. 31 is a cross-sectional view of the display system 2Q according to the fourteenth embodiment.

As shown in FIG. 31, in the display system 2Q according to the fourteenth embodiment, the display surface 130 of the display element 118 is in contact with the surface of the reflective polarizing plate 134 on the side facing the display element 118. Other configurations of the display system 2Q are the same as those of the tenth embodiment.

[14-2. effect]
In the present embodiment, since the display surface 130 of the display element 118 is in contact with the surface of the reflective polarizing plate 134 on the side facing the display element 118, the distance between the display element 118 and the reflective polarizing plate 134 is set. It can be kept short, and the display system 2Q can be miniaturized.

(Embodiment 15)
[15-1. Display system configuration]
The configuration of the display system 2R according to the fifteenth embodiment will be described with reference to FIG. 32. FIG. 32 is a cross-sectional view of the display system 2R according to the fifteenth embodiment.

As shown in FIG. 32, in the display system 2R according to the fifteenth embodiment, the display element 118, the optical element 120L, and the mirror 122 are arranged on the overhead console 156 of the vehicle 4 (see FIG. 21). The display element 118 is arranged on the ceiling 94 side of the vehicle 4, and the mirror 122 is also arranged on the ceiling 94 side of the vehicle 4.

Further, the display system 2R includes a mirror 152 (an example of a second mirror) in addition to the display element 118, the optical element 120L, and the mirror 122. The mirror 152 is a planar mirror and has a planar reflecting surface 154. The mirror 152 is formed by depositing a reflective metal film such as aluminum on the surface of a resin-molded member, for example. The mirror 152 is arranged so that the reflective surface 154 faces the surface of the reflective polarizing plate 134 on the side facing the display element 118. The mirror 152 is supported by, for example, a support member (not shown) arranged below the overhead console 156.

[15-2. Display system operation]
Next, the operation of the display system 2R according to the fifteenth embodiment will be described with reference to FIG. 32.

As shown in FIG. 32, the light emitted from the display surface 130 of the display element 118 is reflected by (i) the reflective surface 138 of the mirror 122 and (ii) the reflective polarizing plate 134, as in the ninth embodiment. (Iii) Reflects again on the reflecting surface 138 of the mirror 122.

After that, the light (second circularly polarized light) reflected again by the reflecting surface 138 of the mirror 122 is converted into the first linearly polarized light by the retardation plate 136 in the same manner as in the above embodiment 10, and is converted to the glass substrate 132 and the reflection. It passes through the type polarizing plate 134. After that, in the present embodiment, the first linearly polarized light transmitted through the reflective polarizing plate 134 is directed toward the mirror 152, reflected by the reflection surface 154 of the mirror 152, and incident on the eyes 32 of the driver 10.

[15-3. effect]
In the present embodiment, by arranging the display system 2R so that the reciprocating reflection of light between the reflective polarizing plate 134 and the mirror 122 is in the vertical direction, the thickness of the display system 2R is reduced in the vertical direction. Can be planned. As a result, the visibility of the driver 10 can be secured. Further, since the mirror 152 is a planar mirror, sunlight incident from the rear of the vehicle 4 is hardly collected. Therefore, it is possible to suppress the temperature rise caused by the light collection.

The display system 2R may include a half mirror instead of the mirror 152 described above. As a result, the driver 10 can see the image formed by the light reflected by the mirror 152 superimposed on the scenery in front of the vehicle 4 seen through the half mirror. That is, the display system 2R is used as a head-up display (HUD) for a vehicle.

(Embodiment 16)
[16-1. Display system configuration]
The configuration of the display system 2S according to the 16th embodiment will be described with reference to FIG. 33. FIG. 33 is a schematic diagram showing the display system 2S according to the sixteenth embodiment.

As shown in FIG. 33, in the display system 2S according to the 16th embodiment, when the display system 2S is viewed from the XZ side, the normal vector N passing through the center of the reflection surface 138 of the mirror 122 is a display of the display element 118. The center side of the display surface 130 is closer to the center side of the half-angle vector A that bisects the angle θ (for example, 35 °) formed by connecting the center of the surface 130, the center of the reflection surface 138 of the mirror 122, and the eyes 32 of the driver 10. It is arranged so that it faces. The distance between the mirror 122 and the upper end portion 120a of the optical element 120L is shorter than the distance between the mirror 122 and the lower end portion 120b of the optical element 120L.

When the display system 2S is viewed from the XZ side, the light emitted from the display surface 130 of the display element 118 in the vertical direction (Z-axis direction) of the optical element 120L is the reflection type polarizing plate 134 and the mirror 122. The angle is set so that it is incident on the eyes 32 of the driver 10 after making two round trips between and. Further, even when the display system 2S rotates with respect to the ball joint 38 (see FIG. 21), the positional relationship between the normal vector N and the half-width vector A is constant.

As a result, as shown by the broken arrow in FIG. 33, of the light emitted from the display surface 130 of the display element 118, a part of the light reflected once by the reflection surface 138 of the mirror 122 is transmitted through the optical element 120L. Then, it advances toward the display surface 130 of the display element 118. As a result, it is possible to suppress the light reflected only once by the mirror 122 from reaching the eyes 32 of the driver 10, and suppress the reflection on the image displayed on the display surface 130 of the display element 118. Can be done.

Further, among the light emitted from the display surface 130 of the display element 118, the light reflected by the reflection surface 138 of the mirror 122 three times or more passes through the optical element 120L and is directed downward from the eyes 32 of the driver 10. You will be able to proceed. As a result, the light reflected by the mirror 122 three times or more can be suppressed from reaching the eyes 32 of the driver 10, and the reflection on the image displayed on the display surface 130 of the display element 118 can be suppressed. Can be done.

Further, when the external light from the rear of the vehicle 4 is incident on the optical element 120L, the external light is transmitted by the optical element 120L and then reflected by the reflecting surface 138 of the mirror 122. At this time, the external light reflected by the reflecting surface 138 of the mirror 122 passes through the optical element 120L and travels toward the display surface 130 of the display element 118. As a result, it is possible to prevent the outside light from reaching the eyes 32 of the driver 10.

34 and 35 are schematic views showing a display system 200S according to a comparative example. As shown in FIG. 34, in the display system 200S according to the comparative example, the normal vector N is arranged so as to overlap the half-width vector A when the display system 200S is viewed from the XZ side. The distance between the mirror 122 and the upper end portion 120a of the optical element 120L is substantially equal to the distance between the mirror 122 and the lower end portion 120b of the optical element 120L. In this case, since the light reflected by the mirror 122 reaches the eyes 32 of the driver 10 one or more times, reflection on the image displayed on the display surface 130 of the display element 118 occurs.

On the other hand, as shown in FIG. 35, in the display system 200S according to another comparative example, the normal vector N is arranged on the side opposite to the display surface 130 with respect to the half-width vector A when the display system 200S is viewed from the XZ side. Has been done. The distance between the mirror 122 and the upper end portion 120a of the optical element 120L is longer than the distance between the mirror 122 and the lower end portion 120b of the optical element 120L. In this case, since the light reflected by the mirror 122 reaches the eyes 32 of the driver 10 one or more times, reflection on the image displayed on the display surface 130 of the display element 118 occurs. Further, when the external light from the rear of the vehicle 4 is incident on the optical element 120L, the external light is transmitted by the optical element 120L and then reflected by the reflecting surface 138 of the mirror 122. At this time, the external light reflected by the reflecting surface 138 of the mirror 122 passes through the optical element 120L and reaches the eyes 32 of the driver 10.

From these, by adopting the configuration of FIG. 33, it is possible to suppress the reflection and suppress the arrival of the outside light to the eyes 32 of the driver 10.

[16-2. Modification example]
FIG. 36 is a front view showing the mirror 122S according to the modified example. As shown in FIG. 36, the mirror 122S according to the modified example is a concave mirror. When the mirror 122S is viewed from the front of YZ, each of the upper side 122a and the lower side 122b of the mirror 122S is formed in a curved shape that is convex upward. Further, each of the left side 122c and the right side 122d of the mirror 122S is formed in a straight line, and the length of the left side 122c (the vertical side on the side far from the driver 10) is the right side 122d (the vertical side on the side close to the driver 10). Longer than the length of the side). That is, the mirror 122S is formed in a bow shape as a whole. However, it is assumed that the vehicle 4 is a vehicle with a right-hand drive.

When the vehicle 4 is a vehicle with a left-hand drive, the length of the left side 122c (the vertical side on the side closer to the driver 10) is the length of the right side 122d (the vertical side on the side far from the driver 10). It will be shorter than that.

As a result, when the driver 10 looks up at the mirror 122S from the driver's seat 8 from diagonally below, the shape of the rear image reflected by the reflecting surface 138 of the mirror 122S can be made closer to a rectangle when viewed from the driver 10.

(Other variants)
The display system according to one or more embodiments has been described above based on each of the above embodiments, but the present disclosure is not limited to each of the above embodiments. As long as it does not deviate from the gist of the present disclosure, a form in which various modifications conceived by those skilled in the art are applied to each of the above embodiments, or a form constructed by combining components in different embodiments is also a form of one or a plurality of embodiments. It may be included in the range.

In the above embodiments 9 to 16, the mirror 122 is a concave mirror, but the mirror 122 is not limited to this, and may be, for example, a Fresnel mirror having a Fresnel-like reflecting surface.

Further, the arrangement of the optical system components such as the concave mirror 26 and the mirror 122, the display element 12 (118), and the eye 32 in each of the above embodiments is an example, and the arrangement is limited to these. is not it.

Further, in each of the above embodiments, the optical element 28 (28A, 28C, 28G, 120, 120L, 120N, 120P) is formed in a flat plate shape, but the present invention is not limited to this, and the optical element 28 may be formed in a cylindrical shape, for example. ..

The display system according to the present disclosure can be applied to, for example, an electronic mirror mounted on a vehicle.

2,2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, 2J, 2K, 2L, 2M, 2N, 2P, 2Q, 2R, 2S, 200, 200S Display system 4 Vehicle 6,156 Overhead console 8 Operation Seat 10 Driver 12,118,204 Display elements 14, 14A, 14B, 14C, 14D, 14E, 14F, 14G Optical reflectors 16, 130, 214 Display surface 18 Recesses 20, 46, 54, 54C, 84, 72, 136 Phase difference plate 22, 22A, 22B, 22C, 22D, 22E, 22F, 22G, 116, 202 Housing 24, 128, 212 Dustproof cover 26, 208 Concave mirror 28, 28A, 28C, 28G, 120, 120L, 120N, 120P, 206 Optical element 30 Incident part 32 Eye 34 Exit part 36 Storage space 38 Ball joint 40, 42, 68, 86, 126, 210 Opening 44, 66, 91, 138, 154 Reflective surface 48, 48a, 48b , 74, 82, 132 Glass substrate 50, 76, 80, 134 Reflective polarizing plate (polarizing element)
52,150,150P Transmissive polarizing plate (polarizing element)
56 Virtual image 58 Windshield 60 LCD mirror 62 TN LCD 64,90 Flat mirror 70,78 Half mirror 88,146 Shading member 92 Holding member 92a First holding part 92b Second holding part 92c Connecting part 94 Ceiling 116a Side surface 120a Top Part 120b Lower end part 122, 122S, 152 Mirror 122a Upper side 122b Lower side 122c Left side 122d Right side 124 Storage space 144 First reflection area 146 Second reflection area

Claims (33)

It is a display system that is mounted on a mobile body and displays an image to the user.
A display element having a display surface that emits light representing the image,
A first mirror that reflects light emitted from the display surface of the display element, and
An optical element, which is arranged to face the first mirror and includes a retardation plate and a polarizing element, is provided.
The first mirror and the optical element are arranged separately from the display element.
The optical element has (i) light emitted from the display surface of the display element transmits the reflected light reflected by the first mirror, and (ii) is incident on the optical element from the side where the reflected light is emitted. A display system that reflects the external light reflected by the first mirror on the surface of the optical element facing the first mirror. The display element is fixed to the moving body and is fixed to the moving body.
The display system is further rotatably supported with respect to the moving body, and has an incident portion for incident light emitted from the display surface of the display element and the incident light directed to the user's eyes. It is provided with an emission unit having an emission unit and an optical reflection unit having the emission unit.
The optical reflection unit is
With the first mirror
It has the optical element arranged in the emitting portion, and has.
The light emitted from the display surface of the display element is reflected by the first mirror at least once, passes through the retardation plate of the optical element and the polarizing element in this order, and is incident on the user's eyes. The display system according to claim 1. The optical reflection unit is further arranged so as to face the display surface of the display element, and a second mirror arranged on an optical path between the display surface of the display element and the first mirror. The display system according to claim 2. The second mirror is arranged so as to face the optical element.
The polarizing element is a reflective polarizing plate and is
The light emitted from the display surface of the display element is reflected by the second mirror and directed toward the optical element, reflected by the optical element and directed toward the first mirror, and reflected by the first mirror. The display system according to claim 3, wherein the display system is directed toward the optical element, passes through the optical element, and is incident on the user's eyes. The optical element is arranged over the incident portion and the exit portion of the optical reflection portion.
The display system according to claim 4, wherein the light emitted from the display surface of the display element passes through the optical element, heads toward the second mirror, and is reflected by the second mirror. The optical reflecting section further has a half mirror disposed in the incident section and disposed between the display element and the second mirror.
The light emitted from the display surface of the display element passes through the half mirror, heads toward the second mirror, is reflected by the second mirror, heads toward the half mirror, and is reflected by the half mirror. It faces the optical element, is reflected by the optical element and is directed toward the first mirror, is reflected by the first mirror and is directed toward the optical element, passes through the optical element, and is incident on the user's eye. The display system according to claim 3. The optical reflector further has a half mirror disposed between the first mirror and the second mirror.
The light emitted from the display surface of the display element is reflected by the second mirror and directed toward the half mirror, transmitted through the half mirror and directed toward the first mirror, and reflected by the first mirror. The display system according to claim 3, wherein the display system faces the half mirror, is reflected by the half mirror, faces the optical element, passes through the optical element, and is incident on the user's eye. The optical element is arranged between the display element and the first mirror.
The light emitted from the display surface of the display element passes through the optical element, heads toward the first mirror, is reflected by the first mirror, heads toward the optical element, and is reflected by the optical element. The display system according to claim 2, wherein the display system faces the first mirror, is reflected again by the first mirror, faces the optical element, passes through the optical element, and is incident on the user's eye. The moving body has a storage portion and has a storage portion.
The display element and the incident portion of the optical reflection portion are housed in the storage portion.
The display system according to any one of claims 2 to 8, wherein the emission portion of the optical reflection portion is exposed to the outside of the storage portion. The display system according to any one of claims 2 to 9, wherein a near-infrared reflecting unit that reflects near-infrared light and transmits visible light is arranged in the emitting unit of the optical reflecting unit. The optical reflection unit further
A housing having an opening arranged in the incident portion and accommodating the first mirror and the optical element inside.
The display system according to any one of claims 2 to 4, 7 to 10, further comprising a translucent cover arranged so as to cover the opening of the housing. According to any one of claims 2 to 11, the display element and the first mirror are arranged so as to be inclined with respect to the traveling direction of the moving body in a top view and are arranged substantially parallel to each other. The display system described. The one according to any one of claims 2 to 12, further comprising a liquid crystal optical element for switching from one of a transmission mode for transmitting incident light and a reflection mode for reflecting incident light to the other. The display system described. A claim that the display system is further arranged on the moving body and includes a holding member for holding the display element and the optical reflection unit to maintain a positional relationship between the display element and the optical reflection unit. The display system according to any one of 2 to 13. The display surface of the display element emits a first linearly polarized light representing the image.
The first mirror is arranged so as to face the display surface of the display element.
The polarizing element is arranged between the display element and the first mirror, transmits the first linear polarization, and reflects a second linear polarization having a polarization direction different from that of the first linear polarization. It is a reflective polarizing plate that
The retardation plate is arranged between the reflective polarizing plate and the first mirror.
The first linearly polarized light emitted from the display surface of the display element (a) passes through the reflective polarizing plate and heads toward the retardation plate, and (b) the first circular polarization by the retardation plate. Is converted to the first mirror, (c) is reflected by the first mirror and directed to the retardation plate, and (d) is converted to the second linear polarization by the retardation plate. A second circle that faces the reflective polarizing plate, (e) is reflected by the reflective polarizing plate and faces the retardation plate, and (f) the retardation plate differs from the first circular polarization in the polarization direction. The display system according to claim 8, wherein the display system is converted into polarized light and directed toward the first mirror, and (g) is reflected again by the first mirror and is incident on the user's eyes. The second circularly polarized light reflected again by the first mirror is further (h) directed to the retardation plate, and (i) is converted into the first linear polarization by the retardation plate to be the reflection type. The display system according to claim 15, wherein the display system faces the polarizing plate, (j) passes through the reflective polarizing plate, and is incident on the user's eyes. The display system further comprises a frame that is arranged on the opposite side of the display element from the first mirror and has an opening.
The display system according to claim 15 or 16, wherein the second circularly polarized light reflected again by the first mirror is incident on the user's eyes through the opening. The display system according to claim 17, wherein the size of the opening is such that the entire width of the first mirror in a predetermined direction can be visually recognized from the user. The display system further includes a housing that houses the display element, the reflective polarizing plate, the retardation plate, and the first mirror.
The display system according to claim 17, wherein the frame constitutes a side surface of the housing on the side facing the user. The display system according to any one of claims 17 to 19, further comprising a light-shielding member arranged between the display element and the opening. The display system according to any one of claims 15 to 20, wherein the polarization direction of the first linear polarization and the polarization direction of the second linear polarization are orthogonal to each other. The retardation plate is a λ / 4 plate and is a λ / 4 plate.
The display system according to any one of claims 15 to 21, wherein the slow-phase axis of the λ / 4 plate is inclined by 45 ° with respect to the reflection axis of the reflective polarizing plate. The display system according to any one of claims 15 to 22, wherein the first mirror and the reflective polarizing plate are arranged non-parallel to each other. The display system according to any one of claims 15 to 23, wherein the first mirror is a concave mirror or a Fresnel mirror. The display system according to any one of claims 15 to 24, wherein the reflective polarizing plate is formed in a cylindrical shape. The display system further comprises a transmissive polarizing plate which is arranged between the display element and the reflective polarizing plate, transmits the first linearly polarized light, and absorbs the second linearly polarized light. The display system according to any one of 15 to 25. The transmissive polarizing plate is arranged so as to cover a region of the surface of the reflective polarizing plate facing the display element to which the first linearly polarized light emitted from the display surface of the display element is incident. The display system according to claim 26. On a straight line connecting the center of the display surface of the display element and the center of the reflection surface of the first mirror, the distance between the display element and the reflective polarizing plate is set between the retardation plate and the first. The display system according to any one of claims 15 to 27, which is shorter than the distance to the mirror. The first mirror is
A first reflection region to which the first circularly polarized light from the retardation plate is reflected,
It has a second reflection region in which the second circularly polarized light from the retardation plate is reflected.
The display system according to any one of claims 15 to 28, wherein a part of the first reflection area overlaps with a part of the second reflection area. The display system further comprises a second mirror arranged to face the surface of the reflective polarizing plate on the side facing the display element.
The first linearly polarized light transmitted through the reflective polarizing plate is further (k) directed toward the second mirror, and (l) reflected by the second mirror and incident on the user's eyes. 16. The display system according to 16. The display system according to any one of claims 15 to 30, further comprising a translucent substrate laminated between the reflective polarizing plate and the retardation plate. The display system according to any one of claims 15 to 31, wherein the display surface of the display element is in contact with a surface of the reflective polarizing plate on the side facing the display element. The first mirror is a concave mirror, and the first mirror is a concave mirror.
When the display system is viewed from the side, the normal vector passing through the center of the reflection surface of the first mirror is the center of the display surface of the display element and the center of the reflection surface of the first mirror. The display system according to any one of claims 15 to 32, which is arranged so as to face the center side of the display surface with respect to the half-angle vector that bisects the angle formed by connecting the user's eyes.

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