Head-up display device, head-up display system

Abstract

The present application relates to a head-up display device. A polarization section (81) is provided between an image section (31) that irradiates projection light (60) and a projection section (vehicle laminated glass (10)) that is projected by the projected light (61). The polarization section (81) transmits light that vibrates in a specific direction included in the projection light (60). The projection light (61) that is transmitted from the polarization section (81) is projected on the projection section. The specific direction in which the projection light (60) is transmitted in the polarization section (81) is a direction parallel to the incident surface. In this case, the head-up display device can be used as a P-HUD type. By adjusting the vibration direction of the light transmitted by the polarization section, the generation of ghost images can be suppressed in the case where a viewer looks obliquely at an image displayed in a region near the periphery of the windshield surface or a central region of the windshield surface.

Description

Technical Field

[0001] This invention relates to head-up display devices, head-up display systems, phase difference films, and laminated glass for vehicles. Background Technology

[0002] As the projection unit of a head-up display (hereinafter sometimes referred to as HUD) device, a windshield is used at the front of the moving body. The occupants see a virtual image based on the reflection of the projected light in the projection unit. The projection unit can form reflected images on two main surfaces: the indoor main surface and the outdoor main surface.

[0003] The reflected images formed on the indoor and outdoor main surfaces of the projection unit cause the virtual image seen by the occupants to be a ghost image (see Non-Patent Document 1 for the structure that produces the ghost image). As a way to suppress ghosting in HUD devices, there are wedge-shaped HUDs and polarized light HUDs.

[0004] In the wedge-shaped HUD method, by making the projection part a component with a wedge-shaped shape with a gradually changing thickness, the optical path of the projection light is adjusted so that when the occupant is viewing, the virtual image based on the reflected image formed on the indoor main surface is consistent with the virtual image based on the reflected image formed on the outdoor main surface (the structure for suppressing ghosting is referred to in Non-Patent Document 1).

[0005] Patent document 1 discloses a polarized light HUD device.

[0006] In polarized light HUD mode, occupants see a virtual image display of the reflected image of the projected light, which is based on S-polarized or P-polarized light, in the projection section. Here, S-polarized light refers to projected light whose vibration direction is perpendicular to the incident surface, while P-polarized light refers to projected light whose vibration direction is parallel to the incident surface.

[0007] In this HUD device, ghosting of reflected images, i.e., ghosting of virtual images, is suppressed using the following structure: The projection unit is a component comprising a first glass plate disposed on the outdoor side, a second glass plate disposed on the indoor side, and a phase retardation film disposed between the first and second glass plates, wherein the materials of each laminated component are adjusted to have the same refractive index in the visible light region. Furthermore, projection light containing the aforementioned S-polarized light or P-polarized light is incident onto the projection unit at a Brewster angle.

[0008] When the incident projection light is composed of S-polarized light, a reflected image is formed on the indoor-side main surface of the second glass panel. Furthermore, the projection light passing through the projection section becomes P-polarized light after passing through a phase retardation film. This P-polarized light, upon reaching the outdoor-side main surface of the first glass panel, is not reflected at that surface but exits outdoors. The occupant sees a virtual image display based on the reflected image formed on the indoor-side main surface of the second glass panel. This situation is referred to as S-HUD.

[0009] Furthermore, when the incident projection light is composed of P-polarized light, the proportion of projection light reflected from the indoor-side main surface of the second glass plate is low. The projection light passing through the projection unit becomes S-polarized light after passing through the retardation film. When this S-polarized light reaches the outdoor-side main surface of the first glass plate, part of it is reflected by the main surface, and the remainder is emitted from the outdoor side. Since the projection light forming this reflected image passes through the retardation film of the projection unit again, it becomes P-polarized light. The occupants see a virtual image display based on the reflected image formed on the indoor-side main surface of the first glass plate, generated by P-polarized light. This situation is recorded as P-HUD.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent document 1: International Publication No. 2019 / 244619.

[0013] Patent Document 2: Japanese Patent Application Publication No. 2000-249966.

[0014] Non-patent literature

[0015] Non-Patent Literature 1: “Development of a Novel Active Driving Display”, Mazda Technology, No. 33 (2016), pp. 60-65 Summary of the Invention

[0016] The problem the invention aims to solve

[0017] In recent years, there has been a demand for diversifying the information displayed on HUD devices. For example, displaying information such as signs and pedestrians can assist driving. Furthermore, there is a desire to share image information between the driver and passenger seats. Information to be shared includes things like information displayed through in-vehicle navigation systems and weather information.

[0018] In order to meet the purpose of diversifying the information displayed by the HUD device, it is not enough to display information only in front of the driver. Sometimes it is necessary to display information in areas other than in front of the driver, such as the area on the outer perimeter of the windshield that is closer to the driver's front, or the area between the passenger seat and the driver's seat.

[0019] In the case of virtual image display in polarized light HUD mode as in Patent Document 1, the angle formed by the optical axis of the phase difference film and the vibration direction of the projection light is adjusted to suppress the generation of ghosting, taking into account the frontal display image of the occupant, i.e. the viewer, who sees the information through the HUD.

[0020] Patent document 2 lists the following problem: if a large-area display is desired in the polarized light HUD mode, it is difficult to inject display light at Brewster angle across the entire display area, making large-area display impossible.

[0021] Furthermore, it records how to resolve the Brewster angle deviation caused by the enlargement of the area by changing the wedge angle.

[0022] Patent Document 2 describes a method where the thickness of the windshield laminated glass decreases downwards from the position where the optical rotation film is inserted, and this thickness variation is adjusted according to the thickness of the inserted optical rotation film. Furthermore, by employing this method, a reflected image can be displayed at the location where the optical rotation film is inserted and below it, thereby increasing the display area.

[0023] However, the increase in display area achieved by this method is limited to the part where the rotating film is inserted and its lower part, and is limited to the method of increasing the display area in the vertical direction of the windshield surface.

[0024] Furthermore, reducing the thickness of the laminated glass in the lower direction has the disadvantage of increasing labor and time in the manufacturing process.

[0025] When the occupants are seated on the driver's side and the front passenger side of the mobile vehicle, and the HUD image is displayed in the central area of ​​the windshield, the display area is tilted from the perspective of both occupants (viewers).

[0026] In this situation, even if the head-up display is designed to suppress ghosting by using polarized light HUD to target the image displayed in front of each viewer, sometimes both viewers will see the image as a ghost because the viewer is looking at the image in an angled direction.

[0027] In view of the above problems, the present invention provides a head-up display device that can suppress the occurrence of ghosting when a viewer sees an image displayed in the area near the outer periphery of the windshield or in the central area of ​​the windshield from an oblique direction.

[0028] Solution for solving the problem

[0029] The first aspect of the first embodiment of the present invention relates to a head-up display device mounted on a mobile body, enabling a viewer, who is a passenger of the mobile body, to view a virtual image based on the reflection of projected light at a projection section, characterized in that...

[0030] When the X-axis is defined as the direction horizontal to the ground and orthogonal to the direction of movement of the moving body, the Y-axis is defined as the direction horizontal to the ground and the direction of movement of the moving body, the Z-axis is defined as the direction perpendicular to the ground, and the surface having the viewpoint of the viewer, the emitting point of the projected light, and the reflecting point that is the point where the projected light is reflected is defined as the incident surface,

[0031] The above-mentioned head-up display device has:

[0032] The imaging unit illuminates the aforementioned projection light;

[0033] A polarizing section, disposed between the image section and the projection section, transmits light that vibrates in a specific direction, including the projected light; and

[0034] The aforementioned projection section projects the projection light transmitted from the aforementioned polarization section.

[0035] The aforementioned projection unit is a laminated glass assembly consisting of a second glass plate, a phase retardation film, and a first glass plate arranged sequentially from the indoor side (the side where the projection light is incident) to the outdoor side.

[0036] The projection unit described above has a viewer-facing area and a viewer-obliquely-forward area. The viewer-facing area is the front of the viewer, and the viewer-obliquely-forward area is the area away from the viewer-facing area in any direction along the X-axis.

[0037] The aforementioned projected light is projected at least onto the area diagonally in front of the viewer.

[0038] When the X-axis from which the viewer observes the projection section is set to 0°, and the surface along the phase difference film is set as the projection surface,

[0039] The aforementioned phase retardation film is tilted by θ relative to the X-axis in the aforementioned projection plane. r The aforementioned phase retardation film is a phase retardation film that can change the vibration direction of the projection light incident on the projection surface by means of the aforementioned optical axis.

[0040] The aforementioned specific direction is parallel to the aforementioned incident surface.

[0041] In the head-up display device according to the first aspect of the first embodiment of the present invention, a polarization section is provided between the image section that irradiates the projection light and the projection section that receives the projection light.

[0042] The polarization section allows light that vibrates in a specific direction and is contained in the projection light to be transmitted, and the projection light transmitted from the polarization section is projected onto the projection section.

[0043] In the polarization section, the specific direction in which the projected light is transmitted is parallel to the incident surface. In this case, it can be used as a head-up display device of the P-HUD type.

[0044] This head-up display is suitable for use in sunglasses mode when using polarized sunglasses.

[0045] By adjusting the vibration direction of the transmitted light using a polarizing unit, ghosting can be suppressed when the viewer is viewing the image displayed in the area near the outer periphery of the windshield or in the central area of ​​the windshield at an angle.

[0046] Furthermore, in the head-up display device according to the first aspect of the first embodiment of the present invention, it is preferable that the viewer observes a virtual image based on a reflected image formed on a surface other than the indoor side of the second glass plate.

[0047] In the head-up display device of the present invention, it is preferable that the viewer observes a virtual image based on the reflected image formed on the outdoor side of the first glass plate.

[0048] Furthermore, the second aspect of the first embodiment of the present invention relates to a head-up display device mounted on a mobile body, allowing a viewer, who is a passenger of the mobile body, to view a virtual image based on the reflection of projection light on a projection section, characterized in that...

[0049] When the X-axis is defined as the direction horizontal to the ground and orthogonal to the direction of movement of the moving body, the Y-axis is defined as the direction horizontal to the ground and the direction of movement of the moving body, the Z-axis is defined as the direction perpendicular to the ground, and the surface having the viewpoint of the viewer, the emitting point of the projected light, and the reflecting point that is the point where the projected light is reflected is defined as the incident surface,

[0050] The above-mentioned head-up display device has:

[0051] The imaging unit illuminates the aforementioned projection light;

[0052] A polarizing section, disposed between the image section and the projection section, transmits light that vibrates in a specific direction, including the projected light; and

[0053] The aforementioned projection section projects the projection light transmitted from the aforementioned polarization section.

[0054] The aforementioned projection unit is a laminated glass assembly consisting of a second glass plate, a phase retardation film, and a first glass plate arranged sequentially from the indoor side (the side where the projection light is incident) to the outdoor side.

[0055] The projection unit described above has a viewer-facing area and a viewer-obliquely-forward area. The viewer-facing area is the front of the viewer, and the viewer-obliquely-forward area is the area away from the viewer-facing area in any direction along the X-axis.

[0056] The aforementioned projected light is projected at least onto the area diagonally in front of the viewer.

[0057] When the X-axis is set to 0° when the viewer views the projection section, and the surface along the phase difference film is set as the projection surface,

[0058] The aforementioned retardation film has an optical axis tilted θr relative to the X-axis in the aforementioned projection plane, and the aforementioned retardation film is positioned such that the vibration direction θ of the projected light incident on the aforementioned projection plane is... α A phase difference film that rotates the vibration direction of the incident projection light by 2dθ when the angle between the projection light and the optical axis is set to dθ.

[0059] Let θ be the angle between the incident surface and the X-axis of the projection surface. p In the case of the above vibration direction θ α In the above projection plane, it is 2θ r -θ p The direction.

[0060] In the head-up display device according to the second aspect of the first embodiment of the present invention, the vibration direction of the projection light incident on the projection surface is set to θ. α The angle of inclination of the optical axis of the phase retardation film relative to the X-axis is set as θ. r Let θ be the angle between the incident surface and the X-axis in the projection plane. p In the case of the above vibration direction θ α In the above projection plane, it is 2θ r -θ p The direction.

[0061] When the vibration direction of the projected light incident on the projection surface meets the above conditions, it can be used as a head-up display device of the S-HUD type. Because the S-HUD type head-up display device does not experience image distortion in rainy weather like the P-HUD type, it can display the image clearly.

[0062] Furthermore, when projecting in an oblique direction, for example, at θ r 2θ at 45° r -θ p The direction is not perpendicular to the incident plane.

[0063] In the head-up display device according to the second aspect of the first embodiment of the present invention, it is preferable that the viewer observes a virtual image based on the reflected image formed on the indoor side of the second glass plate.

[0064] In the head-up display device according to the first embodiment of the present invention, it is preferable that there are multiple viewers. For each viewer, a polarization section is provided between the image section and the projection section, and each polarization section has an incident surface as an incident surface provided for each viewer. Each polarization section transmits projection light that vibrates in the specific direction corresponding to each incident surface.

[0065] Furthermore, it is preferable that the polarization section has a transmission axis in which the vibration direction of the transmitted projection light changes to the specific direction, and the orientation of each of the transmission axes is different.

[0066] Furthermore, it is preferable that the projected light is projected onto a central region, which is between the frontal areas of each of the multiple viewers and is equivalent to the area diagonally in front of each of the multiple viewers.

[0067] For multiple viewers, a polarizing unit is installed separately, and the vibration direction of the projected light transmitted through the polarizing unit is adjusted according to the positional relationship between the incident surface and the projection surface for each viewer. This results in a head-up display device that suppresses ghosting when multiple viewers tilt to view the image displayed in the central area of ​​the windshield, regardless of the viewer's angle.

[0068] In the head-up display device according to the first embodiment of the present invention, it is preferable that the projection position of the projection light being projected can be changed in the projection unit.

[0069] Corresponding to the change in the incident surface that accompanies the change in the projection position, the polarization section is movable and can change the vibration direction of the light transmitted from the polarization section.

[0070] If the projection position changes, the incident plane changes. If the polarization section is movable relative to the change of the incident plane, and can change the vibration direction of the light transmitted from the polarization section, then ghosting can be suppressed even when the projection position changes.

[0071] The head-up display system of the first embodiment of the present invention is mounted on a mobile body, enabling a viewer, who is a passenger of the mobile body, to view a virtual image based on the reflection of projection light on a projection section, characterized in that...

[0072] When the X-axis is defined as the direction horizontal to the ground and orthogonal to the direction of movement of the moving body, the Y-axis is defined as the direction horizontal to the ground and the direction of movement of the moving body, the Z-axis is defined as the direction perpendicular to the ground, and the surface having the viewpoint of the viewer, the emitting point of the projected light, and the reflecting point that is the point where the projected light is reflected is defined as the incident surface,

[0073] The above head-up display system has:

[0074] The imaging unit illuminates the aforementioned projection light.

[0075] A polarizing section, disposed between the image section and the projection section, transmits light that vibrates in a specific direction within the projected light.

[0076] The aforementioned projection unit, on which the aforementioned projection light is projected,

[0077] The aforementioned projection unit is a laminated glass assembly consisting of a second glass plate, a phase retardation film, and a first glass plate arranged sequentially from the indoor side (the side where the projection light is incident) to the outdoor side.

[0078] The projection unit described above has a viewer-facing area and a viewer-obliquely-forward area. The viewer-facing area is the front of the viewer, and the viewer-obliquely-forward area is the area away from the viewer-facing area in any direction along the X-axis.

[0079] The aforementioned projected light is projected at least in the area diagonally in front of the viewer.

[0080] When the X-axis from which the viewer observes the projection section is set to 0°, and the surface along the phase difference film is set as the projection surface,

[0081] The aforementioned phase retardation film is tilted by θ relative to the X-axis in the aforementioned projection plane. r The phase retardation film is a phase retardation film that changes the vibration direction of the projection light incident on the projection surface by means of the optical axis.

[0082] The aforementioned polarization section is movable, and by changing the vibration direction of the light transmitted from the polarization section, it is possible to switch between (A) and (B) below.

[0083] (A) Make the vibration direction of the light incident on the second glass plate parallel to the incident surface.

[0084] (B) The phase retardation film is positioned in the vibration direction θ of the projection light incident on the projection surface. α With the angle between the incident light and the optical axis set to dθ, the vibration direction of the incident projection light is rotated by 2dθ, and the angle between the incident surface and the X-axis of the projection surface is set to θ. pIn this case, the phase retardation film makes the vibration direction of the light transmitted from the second glass plate 2θ in the projection plane. r -θ p The direction.

[0085] In the head-up display system according to the first embodiment of the present invention, the polarization section is movable, and the vibration direction of the light transmitted from the polarization section can be changed. Therefore, switching between S-HUD and P-HUD modes is possible.

[0086] This allows for the development of head-up display systems with multiple methods for suppressing ghosting.

[0087] In the head-up display system according to the first embodiment of the present invention, the projection position of the projection light can be changed in the projection unit.

[0088] Corresponding to the change in the incident surface that accompanies the change in the projection position, the polarization section is movable and can change the vibration direction of the light transmitted from the polarization section.

[0089] If the projection position changes, the incident plane changes. If the polarization section is movable relative to the change of the incident plane, and can change the vibration direction of the light transmitted from the polarization section, then ghosting can be suppressed even when the projection position changes.

[0090] The first aspect of the second embodiment of the present invention relates to a head-up display device, which is mounted on a mobile body, allowing a viewer, who is a passenger of the mobile body, to view a virtual image based on the reflection of projection light on a projection section, characterized in that...

[0091] Let the X-axis be a direction horizontal to the ground and orthogonal to the direction of movement of the moving body, the Y-axis be a direction horizontal to the ground and the direction of movement of the moving body, and the Z-axis be a direction perpendicular to the ground. Let the surface having the viewpoint of the viewer, the emitting point of the projected light, and the reflecting point that is the point where the projected light is reflected be the incident surface.

[0092] The above-mentioned head-up display device has:

[0093] The imaging unit irradiates the aforementioned projection light whose vibration direction is the X-axis direction, and

[0094] The projection unit, on which the aforementioned projection light is projected,

[0095] The projection unit is positioned in the forward direction of the moving body, closer to the viewer than the viewer, and is made of laminated glass. The laminated glass includes: a second glass plate disposed on the side where the projection light enters, a first glass plate disposed on the side where the projection light exits, and a phase retardation film disposed between the second glass plate and the first glass plate.

[0096] The aforementioned first glass panel has a first main surface exposed on the outdoor side, and a second main surface opposite to the first main surface.

[0097] The second glass panel has a fourth main surface exposed on the indoor side, and a third main surface on the opposite side of the fourth main surface.

[0098] By directing the projected light into the phase retardation film, the vibration direction of the projected light can be converted into a direction parallel to the incident surface.

[0099] The projection unit described above has a viewer-facing area and a viewer-obliquely-forward area. The viewer-facing area is the front of the viewer, and the viewer-obliquely-forward area is the area away from the viewer-facing area in any direction along the X-axis.

[0100] When a viewer views a reflected image formed in the area in front of the viewer, the optical axis of the phase retardation film disposed in the area in front of the viewer is at an angle of 45° ± 5° relative to the X-axis in a plane parallel to the fourth principal plane.

[0101] When a viewer views a reflected image formed in the region diagonally in front of the viewer, the optical axis of the retardation film disposed in the region diagonally in front of the viewer is tilted in the following direction in a plane parallel to the fourth principal plane, the direction being offset from 45°±5° relative to the X-axis.

[0102] The aforementioned virtual image is a virtual image based on the reflected image formed on the fourth principal surface of the second glass plate.

[0103] In either the area in front of the viewer or the area diagonally in front of the viewer, the light emitted from the first main surface of the first glass plate is the projected light that vibrates primarily in a direction parallel to the incident surface.

[0104] In the description of the second embodiment of the present invention, the length of the line along the Y-axis (the distance from the viewpoint to the projection unit) connecting the viewer's viewpoint and the projection unit is set to 1000 mm, and the range of ±10° along the X-axis direction when the line along the Y-axis is set to 0° is set as the viewer's front area.

[0105] The area that is away from the viewer's frontal area in any direction along the X-axis is defined as the area diagonally in front of the viewer.

[0106] In the head-up display device according to the first aspect of the second embodiment of the present invention, when viewing a reflected image formed in the viewer's front area, which is the viewer's front, the optical axis of the retardation film is at 45°±5° relative to the X-axis in a plane parallel to the fourth main surface. In the viewer's front area, the projected light is almost entirely S-polarized light. Since the efficiency of converting the projected light (S-polarized light) incident on the retardation film in the viewer's front area into P-polarized light is high, ghosting is suppressed.

[0107] When viewing a reflected image formed in a region that is far from the viewer's frontal area in any direction along the X-axis, i.e., the region obliquely in front of the viewer, the optical axis of the phase retardation film in a plane parallel to the fourth principal plane is tilted in the following direction, which is offset from the X-axis at 45°±5°.

[0108] By tilting the optical axis of the retardation film in a direction offset from the X-axis by 45°±5°, it corresponds to the change in the incident plane of the projected light, thereby increasing the proportion of light vibrating in the direction parallel to the incident plane in the light transmitted through the retardation film. As a result, the efficiency of converting the projected light incident on the retardation film into P-polarized light in the region obliquely in front of the viewer is also increased, thus suppressing ghosting.

[0109] Since the efficiency of converting projected light into P-polarized light is increased in both the area in front of the viewer and the area diagonally in front of the viewer, ghosting is suppressed.

[0110] As a result, a head-up display device can be provided that can suppress ghosting even when the display area of ​​the HUD is horizontally expanded on the windshield surface.

[0111] Furthermore, the second embodiment of the present invention relates to a head-up display device mounted on a mobile body, allowing a viewer, who is a passenger of the mobile body, to observe a virtual image based on the reflection of projection light at a projection section, characterized in that...

[0112] When the X-axis is defined as the direction horizontal to the ground and orthogonal to the direction of movement of the moving body, the Y-axis is defined as the direction horizontal to the ground and the direction of movement of the moving body, the Z-axis is defined as the direction perpendicular to the ground, and the surface having the viewpoint of the viewer, the emitting point of the projected light, and the reflecting point that is the point where the projected light is reflected is defined as the incident surface,

[0113] The above-mentioned head-up display device has:

[0114] The imaging unit irradiates the aforementioned projection light whose vibration direction is parallel to the YZ plane, and

[0115] The projection unit, on which the aforementioned projection light is projected,

[0116] The projection unit is positioned closer to the moving body in its forward direction than the viewer, and is made of laminated glass. The laminated glass includes: a second glass plate disposed on the side where the projection light enters, a first glass plate disposed on the side where the projection light exits, and a phase retardation film disposed between the second and first glass plates.

[0117] The aforementioned first glass panel has a first main surface exposed on the outdoor side, and a second main surface opposite to the first main surface.

[0118] The second glass panel has a fourth main surface exposed on the indoor side, and a third main surface on the opposite side of the fourth main surface.

[0119] By directing the projected light into the phase retardation film, the vibration direction of the projected light can be converted to a direction perpendicular to the incident surface.

[0120] The projection unit described above has a viewer-facing area and a viewer-obliquely-forward area. The viewer-facing area is the front of the viewer, and the viewer-obliquely-forward area is the area away from the viewer-facing area in any direction along the X-axis.

[0121] When a viewer views a reflected image formed in the area in front of the viewer, the optical axis of the phase retardation film disposed in the area in front of the viewer is at an angle of 45° ± 5° relative to the X-axis in a plane parallel to the fourth principal plane.

[0122] When a viewer views a reflected image formed in the region diagonally in front of the viewer, the optical axis of the retardation film disposed in the region diagonally in front of the viewer is tilted in a direction parallel to the fourth principal plane, which is a direction offset from the X-axis at 45°±5°.

[0123] The aforementioned virtual image is a virtual image based on the reflected image formed on the first principal surface of the first glass plate.

[0124] In either the area in front of the viewer or the area diagonally in front of the viewer, the light reflected from the first main surface of the first glass plate is mainly the projected light that vibrates in a direction perpendicular to the incident surface.

[0125] The head-up display is also compatible with sunglasses mode when using polarized sunglasses.

[0126] In this head-up display device, when viewing the reflected image formed in the viewer's front area (the area directly in front of the viewer), the optical axis of the retardation film is at 45° ± 5° relative to the X-axis in a plane parallel to the fourth principal surface. In the viewer's front area, the projected light is almost entirely P-polarized. In the viewer's front area, because the efficiency of converting the projected light (P-polarized light) incident on the retardation film into S-polarized light is higher, the virtual image display based on the reflected image formed on the first principal surface of the first glass plate is stronger. Therefore, the influence of the projected light reflected from the fourth principal surface is relatively weaker, and ghosting can be suppressed.

[0127] When viewing a reflected image formed in a region that is far from the viewer's frontal area in any direction along the X-axis, i.e., the region obliquely in front of the viewer, the optical axis of the phase retardation film in a plane parallel to the fourth principal plane is tilted in the following direction, which is offset from the X-axis at 45°±5°.

[0128] By tilting the optical axis of the retardation film in a direction offset from the X-axis by 45°±5°, it corresponds to the change in the incident surface of the projected light, thereby increasing the proportion of light vibrating in the direction perpendicular to the incident surface in the light transmitted through the retardation film. As a result, the virtual image display based on the reflected image formed on the first principal surface of the first glass plate is also strengthened in the region obliquely in front of the viewer. Therefore, the influence of the projected light reflected from the fourth principal surface is relatively weakened, and the occurrence of ghosting can be suppressed.

[0129] Since the efficiency of converting projected light into S-polarized light is increased in both the area in front of the viewer and the area diagonally in front of the viewer, ghosting is suppressed.

[0130] As a result, a head-up display device can be provided that can suppress ghosting even when the display area of ​​the HUD is horizontally expanded on the windshield surface.

[0131] In the head-up display device according to the second embodiment of the present invention, preferably, in the right peripheral region located to the right of the frontal region of the viewer in the region diagonally in front of the viewer, and in the left peripheral region located to the left of the frontal region of the viewer, the direction in which the optical axis of the phase difference film is offset from the direction of 45°±5° relative to the X-axis is opposite.

[0132] This setting can suppress ghosting on both sides of the viewer.

[0133] In the head-up display device according to the second embodiment of the present invention, it is preferable that the change in the tilt of the optical axis direction of the phase difference film in the region diagonally in front of the viewer is continuous along the X-axis direction.

[0134] Furthermore, it is preferable that the change in the tilt of the optical axis of the phase difference film in the region diagonally in front of the viewer is discontinuous along the X-axis direction.

[0135] Furthermore, the phase retardation film according to the second embodiment of the present invention has a vertical axis in the up-down direction and a horizontal axis in the left-right direction. This phase retardation film is an integral phase retardation film, characterized in that...

[0136] At multiple points along the aforementioned vertical axis, the angle between the optical axis of the aforementioned retardation film and the aforementioned horizontal axis is fixed.

[0137] Along the aforementioned horizontal axis, the angle between the optical axis of the aforementioned phase difference film and the aforementioned horizontal axis varies with a fixed tendency.

[0138] By aligning the phase retardation film with the transverse direction of the windshield, it is possible to provide a HUD device that has a wide display area in the transverse direction of the windshield surface.

[0139] In the retardation film according to the second embodiment of the present invention, it is preferable that the angle between the optical axis of the retardation film and the horizontal axis changes continuously along the horizontal axis direction.

[0140] Furthermore, preferably, along the aforementioned horizontal axis, the angle between the optical axis of the phasor film and the aforementioned horizontal axis varies discontinuously.

[0141] Furthermore, the second embodiment of the present invention relates to a laminated glass for vehicles, which includes a first glass plate, a second glass plate, and a phase difference film disposed between the first glass plate and the second glass plate, characterized in that...

[0142] The aforementioned phase retardation film is the phase retardation film according to the second embodiment of the present invention.

[0143] When using such laminated glass for vehicles, it is possible to provide a HUD device with a wide display area in the lateral direction on the windshield surface.

[0144] The second embodiment of the head-up display system of the present invention is mounted on a mobile body, enabling a viewer, who is a passenger of the mobile body, to observe a virtual image based on the reflection of projection light at a projection section, characterized in that...

[0145] When the X-axis is defined as the direction horizontal to the ground and orthogonal to the direction of movement of the moving body, the Y-axis is defined as the direction horizontal to the ground and the direction of movement of the moving body, the Z-axis is defined as the direction perpendicular to the ground, and the surface having the viewpoint of the viewer, the emitting point of the projected light, and the reflecting point that is the point where the projected light is reflected is defined as the incident surface,

[0146] The above head-up display system has:

[0147] The imaging unit illuminates the aforementioned projection light.

[0148] The projection unit, on which the aforementioned projection light is projected,

[0149] The projection unit is positioned closer to the moving body in its forward direction than the viewer, and is made of laminated glass. The laminated glass includes: a second glass plate disposed on the side where the projection light enters, a first glass plate disposed on the side where the projection light exits, and a phase retardation film disposed between the second glass plate and the first glass plate.

[0150] The aforementioned first glass panel has a first main surface exposed on the outdoor side, and a second main surface opposite to the first main surface.

[0151] The second glass panel has a fourth main surface exposed on the indoor side, and a third main surface on the opposite side of the fourth main surface.

[0152] By directing the projected light into the phase retardation film, the vibration direction of the projected light can be converted into a direction parallel to or perpendicular to the incident surface.

[0153] The projection unit described above has a viewer-facing area and a viewer-obliquely-forward area, wherein the viewer-facing area is the front of the viewer, and the viewer-obliquely-forward area is the area away from the viewer-facing area in any direction along the X-axis.

[0154] In the case where a viewer observes the reflected image formed in the area in front of the viewer, the phase retardation film disposed in the area in front of the viewer is on a plane parallel to the fourth principal plane, and the optical axis of the phase retardation film is at an angle of 45° ± 5° relative to the X-axis.

[0155] When a viewer observes a reflected image formed in the region diagonally in front of the viewer, the optical axis of the retardation film disposed in the region diagonally in front of the viewer is tilted in a direction parallel to the fourth principal plane, which is a direction offset from the X-axis at 45°±5°.

[0156] The aforementioned imaging unit can switch between a first projection light with a vibration direction along the X-axis and a second projection light with a vibration direction parallel to the YZ plane for illumination.

[0157] When the viewer views the virtual image without a polarizer, the first projection light is irradiated from the image unit. The virtual image is a virtual image based on a reflected image formed on the fourth principal surface of the second glass plate. In either the area in front of the viewer or the area diagonally in front of the viewer, the light emitted from the first principal surface of the first glass plate is projection light that vibrates primarily in a direction parallel to the incident surface.

[0158] When the viewer views the virtual image through the polarizer, the second projection light is irradiated from the image section. The virtual image is a virtual image based on the reflected image formed on the first main surface of the first glass plate. In either the area in front of the viewer or the area diagonally in front of the viewer, the light reflected from the first main surface of the first glass plate is projection light that vibrates mainly in a direction perpendicular to the incident surface.

[0159] The head-up display system according to the second embodiment of the present invention can switch between a sunglasses mode for viewing virtual images via polarized sunglasses or other polarized filters and a normal mode for viewing virtual images without polarized filters by switching between two types of projection light irradiated from the image unit.

[0160] Moreover, by horizontally expanding the HUD display area on the windshield surface, ghosting can be suppressed in any mode.

[0161] Invention Effects

[0162] According to the present invention, a head-up display device can be provided that can suppress the occurrence of ghosting when a viewer is viewing an image displayed in the area near the outer periphery of the windshield or in the central area of ​​the windshield at an angle. Attached Figure Description

[0163] Figure 1 This is a top view of a moving body equipped with a HUD.

[0164] Figure 2 This is a view of the vehicle-mounted laminated glass used in the HUD device from the fourth main side.

[0165] Figure 3 This is an exploded perspective view schematically representing an example of laminated glass for vehicles.

[0166] Figure 4 This is a schematic diagram illustrating a first HUD device according to a first aspect of a first embodiment of the present invention, and a schematic diagram of the optical path in the device.

[0167] Figure 5 This is a summary of a second HUD device according to a second aspect of the first embodiment of the present invention, and a schematic diagram of the optical path in the device.

[0168] Figure 6 This is a schematic diagram used to illustrate the vibration direction of light transmitted from the polarization section in a second HUD device.

[0169] Figure 7 This is a diagram that schematically illustrates an example of the relationship between the position of the viewer, the position of the projection section, and the position of the transmission axis of the polarizing section in a first HUD device.

[0170] Figure 8 This is a diagram that schematically illustrates an example of the relationship between the position of the viewer, the position of the projection section, and the position of the transmission axis of the polarizing section in a second HUD device.

[0171] Figure 9 This diagram schematically illustrates an example of the relationship between the position of the viewer, the position of the projection section, and the position of the transmission axis of the polarizing section in a first HUD device with multiple viewers.

[0172] Figure 10 This diagram schematically illustrates an example of the relationship between the position of the viewer, the position of the projection section, and the position of the transmission axis of the polarizing section in a second HUD device with multiple viewers.

[0173] Figure 11 This is a schematic diagram illustrating the configuration of the first HUD device used in the embodiments and comparative examples.

[0174] Figure 12 This is a schematic diagram illustrating the experimental system in Example 1.

[0175] Figure 13 This is a schematic diagram representing the experimental system in Comparative Example 1.

[0176] Figure 14 These are photographs showing the virtual images seen in Example 1 and Comparative Example 1.

[0177] Figure 15 This is a schematic diagram illustrating the experimental system in Example 2.

[0178] Figure 16 This is a schematic diagram representing the experimental system in Comparative Example 2.

[0179] Figure 17 These are photographs showing the virtual images seen in Example 2 and Comparative Example 2.

[0180] Figure 18 This is a diagram schematically illustrating an example of a phase retardation film according to a second embodiment of the present invention.

[0181] Figure 19This is a diagram schematically illustrating an example of another phase retardation film according to the second embodiment of the present invention.

[0182] Figure 20 This is an exploded perspective view schematically illustrating an example of a laminated glass for vehicles according to a second embodiment of the present invention.

[0183] Figure 21 This is a summary of a third HUD device according to the first aspect of the second embodiment of the present invention, and a schematic diagram of the optical path in the device.

[0184] Figure 22 This is a diagram that schematically shows the positions of the area in front of the viewer and the area diagonally in front of the viewer in a right-hand drive vehicle.

[0185] Figure 23 This is a diagram that schematically shows the positions of the area in front of the viewer and the area diagonally in front of the viewer in a left-hand drive vehicle.

[0186] Figure 24 This is a diagram illustrating, in a way that shows the positions of the area in front of the viewer and the area diagonally in front of the viewer in a right-hand drive vehicle where the driver is the viewer.

[0187] Figure 25 This is a diagram illustrating, in a left-hand drive vehicle, the positions of the area in front of the viewer and the area diagonally in front of the viewer when the driver is the viewer.

[0188] Figure 26 This diagram schematically illustrates the positions of the area in front of the viewer and the area diagonally in front of the viewer when the viewer consists of a driver and a front passenger.

[0189] Figure 27 This is a diagram illustrating, in a schematic way, the positions of the area in front of the viewer and the area diagonally in front of the viewer when there are two occupants, the driver and the front passenger.

[0190] Figure 28 This diagram schematically illustrates how the projection section is extended into the side window glass.

[0191] Figure 29 This is an outline of a fourth HUD device according to a second aspect of a second embodiment of the present invention, and a schematic diagram of the optical path in the device.

[0192] Figure 30 This is a schematic diagram illustrating the configuration of the third HUD device used in the embodiments and comparative examples.

[0193] Figure 31 This is a schematic diagram illustrating the experimental system in Example 3.

[0194] Figure 32 This is a schematic diagram representing the experimental system in Comparative Example 3.

[0195] Figure 33 These are photographs showing the virtual images seen in Example 3 and Comparative Example 3.

[0196] Figure 34 This is a schematic diagram illustrating the experimental system in Example 4.

[0197] Figure 35 This is a schematic diagram representing the experimental system in Comparative Example 4.

[0198] Figure 36 These are photographs showing the virtual images seen in Example 4 and Comparative Example 4. Detailed Implementation

[0199] (First Implementation)

[0200] The head-up display device (HUD device) and head-up display system (HUD system) according to the first embodiment of the present invention will be described with reference to the accompanying drawings.

[0201] Furthermore, the HUD device according to the first embodiment of the present invention includes a HUD device in which the viewer observes a virtual image based on a reflected image formed on a surface other than the indoor side of the second glass plate (P-HUD type HUD device), and a HUD device in which the viewer observes a virtual image based on a reflected image formed on the indoor side of the second glass plate (S-HUD type HUD device), which are also referred to as the first HUD device and the second HUD device, respectively. In the description of the head-up display device according to the first embodiment of the present invention, without distinguishing between the first HUD device and the second HUD device, it is simply referred to as the HUD device according to the first embodiment of the present invention.

[0202] Furthermore, the HUD system according to the first embodiment of the present invention is a system that can be used as both a first HUD device and a second HUD device by switching the vibration direction of light transmitted from the polarization section in one system.

[0203] Furthermore, in the description of the first embodiment of the present invention, the length of the line along the Y-axis (the distance from the viewpoint to the projection unit) connecting the viewer's viewpoint and the projection unit is set to 1000 mm, and the range of ±3° along the X-axis direction when the line along the Y-axis is set to 0° is defined as the viewer's frontal area. Furthermore, the viewer's frontal area is also defined when the range is expanded along the Z-axis direction.

[0204] The area that moves away from the viewer's frontal area in any direction along the X-axis is defined as the viewer's oblique frontal area. Furthermore, the areas that move away from the viewer's frontal area along both the X-axis and Z-axis are also defined as the viewer's oblique frontal area.

[0205] Furthermore, in the description of the first embodiment of the present invention, the surface along the retardation film and into which the projection light enters the retardation film is referred to as the projection surface. The projection surface is the surface that includes the main surface of the retardation film.

[0206] Head-up display (HUD)

[0207] In the HUD device according to the first embodiment of the present invention, there are two types: a first HUD device and a second HUD device. First, the definitions of the X-axis, Y-axis, and Z-axis, which are common to both HUD devices, and the moving body will be explained.

[0208] Figure 1 This is a top view of a moving body equipped with a HUD. Figure 2 This is a view of the vehicle-grade laminated glass used in the HUD device from the interior side (fourth main side) of the second glass panel.

[0209] Reference Figure 1 and Figure 2 The orientation of the X-axis, Y-axis and Z-axis in this invention will be explained.

[0210] exist Figure 1 The image shows a vehicle 20 as a moving body, with the X-axis representing the lateral direction and the Y-axis representing the longitudinal direction. The Z-axis is the direction perpendicular to the plane of the paper.

[0211] The Y-axis is horizontal to the ground and is the direction of travel when the vehicle 20, as a moving body, moves forward.

[0212] The X-axis is a direction that is horizontal to the ground and orthogonal to the direction of travel (Y-axis) of the vehicle 20 as it moves forward.

[0213] The Z-axis is the direction perpendicular to the ground.

[0214] Furthermore, the direction of the first glass plate when viewed from the second glass plate side is defined as "front".

[0215] Examples of mobile bodies include vehicles (passenger cars, trucks, buses, trams), trains, ships, and airplanes. Among these, vehicles are preferred.

[0216] Figure 2 A laminated glass 10 for vehicles is shown. When the laminated glass 10 for vehicles is installed in a vehicle, its glass surface is generally not parallel to the XZ plane, but is arranged at an angle from the XZ plane.

[0217] Next, the laminated glass used in vehicles will be explained.

[0218] Figure 3 This is an exploded perspective view schematically representing an example of laminated glass for vehicles.

[0219] The first glass panel has a first main surface exposed on the outdoor side and a second main surface on the opposite side of the first main surface.

[0220] In addition, the second glass panel has a fourth main surface exposed on the indoor side and a third main surface on the opposite side of the fourth main surface.

[0221] In addition, the aforementioned “exposed” means that, within the scope of not impairing the function of laminated glass for vehicles, each main surface may have a thin film or membrane for imparting various functions such as anti-fog and scratch resistance.

[0222] Figure 3 Laminated glass 10 for vehicles is shown.

[0223] Figure 3 The diagram shows a second glass plate 12 arranged near the front side of the attached figure, and the surface visible near the front side is the fourth main surface 124. The surface opposite to the fourth main surface 124 is the third main surface 123.

[0224] A first glass plate 11 is disposed on the inner side of the attached drawing, and the surface visible from the front is the second main surface 112. The surface opposite to the second main surface 112 is the first main surface 111.

[0225] A phase difference film 100 is disposed between the first glass plate 11 and the second glass plate 12.

[0226] Since the fourth main surface 124 is the surface exposed on the interior side, it becomes the surface directly seen by the viewer when the vehicle is fitted with laminated glass. That is, Figure 3 It shows the positional relationships as seen directly from inside the car.

[0227] In laminated glass for vehicles, it is preferable that the first and second glass sheets are bonded together as a single unit via an interlayer. The interlayer is a film that bonds the first and second glass sheets together by heating it to a temperature at which the polymer constituting the interlayer softens. Therefore, polymers such as polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), acrylic resin (PMMA), polyurethane resin, polyethylene terephthalate (PET), and cyclic olefin polymers (COP) can be used. Alternatively, the interlayer may also consist of multiple resin layers.

[0228] As a glass material constituting laminated glass for vehicles, materials that can be processed from flat glass sheets into curved shapes are suitable. In addition to soda-lime silicate glass as specified in ISO 16293-1, known glass materials such as aluminosilicate glass, borosilicate glass, and alkali-free glass can also be used as the material for the glass sheets. The thickness of each of the first and second glass sheets can be, for example, set to 0.4 mm to 3 mm. Furthermore, the spacing between the first and second glass sheets can be set to 0.01 mm to 2.5 mm.

[0229] The phase retardation film 100 is tilted by θ relative to the X-axis in the projection plane. r The optical axis is a phase retardation film that changes the vibration direction of the projection light incident on the projection surface through the optical axis. For example, when the phase retardation film is a 1 / 2 wavelength film, when the angle between the vibration direction of the projection light incident on the projection surface and the optical axis is set as dθ, the vibration direction of the incident projection light is rotated by 2dθ.

[0230] Furthermore, in the first embodiment of the present invention, the optical axis of the retardation film refers to the axis along the direction of maximum refractive index in the retardation film. Additionally, the retardation film may also comprise a layer or film without a substrate. For example, a retardation film in which a layer having an optical axis within the projection section is formed by coating, lamination, bonding, adhesion, pressing, transfer, or the like.

[0231] The phase retardation film is disposed between the first glass plate and the second glass plate.

[0232] The retardation film can be disposed inside the intermediate film, or at the position where it is in contact with the first glass plate, or at the position where it is in contact with the second glass plate. Furthermore, as... Figure 3 As shown, the surface of the retardation film can be configured to face the second principal surface and the third principal surface. Furthermore, the retardation film can be configured over the entire surface or partially, preferably the total area of ​​the surfaces of the retardation film facing the second and third principal surfaces is equal to or less than the areas of the second and third principal surfaces.

[0233] In addition, multiple phase retardation films can be used as needed, or different types of phase retardation films or films other than phase retardation films can be used in combination.

[0234] By arranging the edge of the vehicle laminated glass equipped with the aforementioned phase difference film along the X-axis, a vehicle laminated glass that serves as a windshield can be formed.

[0235] As a phase retardation film, it is possible to use a phase retardation element formed by uniaxial or biaxial stretching of plastic films such as polycarbonate, polyarylate, polyethersulfone, cyclic olefin polymer, triacetyl cellulose, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN), or a phase retardation element that fixes the orientation state by orienting the liquid crystal polymer in a specific direction.

[0236] The former, a phase retardation element formed by uniaxial or biaxial stretching of a plastic film, can utilize films produced by methods such as solvent casting and melt extrusion. Solvent casting involves dissolving a polymer resin in a solvent, coating it onto a smooth surface such as stainless steel strip or polyethylene terephthalate (PET), allowing the solvent to evaporate, and then winding the film. Melt extrusion involves placing a polymer resin into an extruder, heating and melting it, extruding it through a slit (T-die), cooling it, and then winding the film. For stretching, a stretching machine is generally used, which can obtain phase retardation films stretched longitudinally, laterally, and obliquely.

[0237] As the latter type of phase retardation element, a phase retardation element can be used, for example, by heat treatment and cooling of a transparent substrate such as polyethylene terephthalate (PET) or triacetyl cellulose (TAC) after orientation treatment to fix the liquid crystal orientation.

[0238] As examples of the aforementioned liquid crystal polymers, there are no particular limitations as long as the compound exhibits liquid crystal properties such as nematic liquid crystal, twisted nematic liquid crystal, discoid liquid crystal, or cholesteric liquid crystal when oriented in a specific direction. For example, polymers that are twisted nematically oriented in the liquid crystal state and become glassy below the liquid crystal transition point can be used, such as optically active polyesters, polyamides, polycarbonates, polyesterimides, and other main-chain liquid crystal polymers, as well as optically active polyacrylates, polymethacrylates, polymalonates, polysiloxanes, and other side-chain liquid crystal polymers. Furthermore, polymer compositions in which other low- or high-molecular-weight optically active compounds are added to these non-optically active main-chain or side-chain polymers can be used as examples.

[0239] The function of the phase difference film in the first HUD device and the second HUD device will be explained in the following text.

[0240] [First HUD device]

[0241] First, taking a first HUD device as an example, the HUD device involved in the first aspect of the first embodiment of the present invention will be described.

[0242] Figure 4 This is a schematic diagram illustrating a first HUD device according to a first aspect of a first embodiment of the present invention, and a schematic diagram of the optical path in the device.

[0243] exist Figure 4 In the diagram, the light path of the projected light is represented by a solid line.

[0244] In the first HUD device 1, the projection unit is Figure 3 The vehicle shown uses laminated glass 10.

[0245] exist Figure 4 In the first HUD device 1 shown, projection light 60 is irradiated from the image unit 31.

[0246] Here, the plane containing the light-emitting point 32 of the image unit 31, the reflection point 33 of the projection light 60 reflected from the first main surface 111, and the viewpoint 34 of the viewer 35 is the incident surface.

[0247] Although it is not necessary to limit the vibration direction of the projection light 60 emitted from the image unit 31, if it is P-polarized light with the vibration direction parallel to the incident surface, the amount of light passing through the polarization unit 81 will increase, which can increase the amount of light reaching the first main surface, and is therefore preferred.

[0248] In a vehicle, the imaging unit 31 is preferably located in the vehicle's dashboard or the like.

[0249] By changing the direction of the projection light 60 illuminating the image unit 31 or moving the position of the image unit 31, the position of the projection light 60 can be moved.

[0250] A polarizing section 81 is provided between the image section 31 and the projection section (vehicle laminated glass 10). The polarizing section 81 is a component that has a transmission axis that changes the vibration direction of the transmitted projection light 60 to a specific direction, and a known polarizer can be used, for example.

[0251] It is desirable that the polarizer described above has an absorption axis that absorbs light vibrating in a direction perpendicular to the specific direction described above. If it has a transmission axis and an absorption axis as described above, then, for example, when light that does not vibrate in either direction along the transmission axis and the absorption axis is incident, it is easy to make the vibration direction of the transmitted light become the specific direction described above.

[0252] The polarizing section 81 only needs to be positioned so that the projected light 60 can pass through it before reaching the projection section. For example, in a vehicle, the polarizing section 81 is disposed in the dashboard in the same manner as the image section 31 described above, and is preferably disposed adjacent to the light source so that the light from the light source is quickly transmitted through the polarizing section 81.

[0253] In the first HUD device 1, the polarization section 81 transmits light that vibrates in a direction parallel to the incident plane. That is, the projected light 61 transmitted from the polarization section 81 becomes P-polarized light.

[0254] When the projected light 61 transmitted from the polarization section 81 is P-polarized light, it can be used even in sunglasses mode when viewing a virtual image through polarized sunglasses. Furthermore, in Figure 4 Polarized sunglasses 36 are used, so the virtual image can be observed even with the naked eye. First, the projection light 60 emitted from the image unit 31 is transmitted through the polarization unit 81, and thus the projection light 61, as P-polarized light, is irradiated onto the fourth principal surface 124. It is desirable that the angle at this time is Brewster's angle. Normally, since P-polarized light incident at Brewster's angle does not undergo reflection, the reflection on the fourth principal surface 124 that causes ghosting can be suppressed.

[0255] It can move in the X-axis and Y-axis directions in such a way that the angle at which the projection light 61 illuminates the fourth main surface 124 is the Brewster angle.

[0256] Next, the projection light 61 advancing in the projection section changes its vibration direction when it is incident on the phase difference film 100.

[0257] In the first HUD device 1, reflection can occur on any surface other than the fourth main surface, so a half-wavelength film, a quarter-wavelength film, etc. can be used as the phase difference film 100.

[0258] The vibration direction of light after passing through the phase retardation film 100 varies depending on the type of phase retardation film and the orientation of the optical axis. For example, when using a 1 / 2 wavelength film as the phase retardation film, if the angle between the vibration direction of the projection light incident on the projection surface and the optical axis of the phase retardation film is set as dθ, the vibration direction of the projection light becomes a direction rotated by 2dθ.

[0259] Next, the projected light is reflected when it reaches the first principal surface 111, forming a reflected image. At this time, the S-polarized light is reflected as reflected light, while the other unreflected light passes through the first principal surface 111 and is emitted to the outside.

[0260] Next, the reflected image formed on the first principal surface 111 passes through the phase retardation film 100 again and becomes P-polarized light. The viewer 35 sees a virtual image 621 based on the reflected image on the first principal surface 111, located on the extension line of the optical path 62.

[0261] Since the virtual image 621 is composed of P-polarized light, the viewer 35 can see the virtual image 621 even through polarized sunglasses 36.

[0262] In this case, the viewer observes a virtual image based on the reflected image formed on the outdoor side (i.e., the first main surface) of the first glass plate.

[0263] Furthermore, in the case where a reflective layer is provided to reflect light before it reaches the first principal surface 111, reflection occurs in this layer. In this case, if unreflected light reaches the first principal surface 111 and is further reflected, the emission may sometimes cause ghosting. Therefore, in the case where reflection occurs before reaching the first principal surface 111, it is preferable to change the vibration direction of the light before reaching the first principal surface 111 to make it P-polarized again.

[0264] When such a situation is included, it is preferable for the viewer to observe a virtual image based on a reflected image formed on a surface other than the interior side of the second glass plate. "A reflected image formed on a surface other than the interior side of the second glass plate" also includes "a reflected image formed on the exterior side of the first glass plate".

[0265] Furthermore, in the first HUD device, the polarization section 81 is preferably movable, capable of changing the vibration direction of the light transmitted from the polarization section 81.

[0266] If the polarization section 81 is movable, then when the incident surface changes, by moving the polarization section 81, the aforementioned specific direction can be aligned with the direction parallel to the incident surface. By aligning this specific direction with the direction parallel to the incident surface, it can be used as a P-HUD type HUD device.

[0267] [Second HUD device]

[0268] Next, taking the second HUD device as an example, the HUD device according to the second aspect of the first embodiment of the present invention will be described.

[0269] Figure 5 This is a summary of a second HUD device according to a second aspect of the first embodiment of the present invention, and a schematic diagram of the optical path in the device.

[0270] exist Figure 5 In the diagram, the light path of the projected light is represented by a solid line.

[0271] In the second HUD device 2, the projection unit is Figure 3 The vehicle shown uses laminated glass 10.

[0272] A polarizing section 82 is provided between the image section 31 and the projection section (vehicle laminated glass 10). The polarizing section 82 is a component that has a transmission axis that transmits light containing the projection light that vibrates in a specific direction, such as a known polarizer.

[0273] The polarizing section 82 only needs to be positioned so that the projected light 40 can pass through it before reaching the projection section. For example, in a vehicle, the polarizing section 82 is disposed in the dashboard in the same manner as the image section 31 described above, and is preferably disposed adjacent to the light source so that the light from the light source is quickly transmitted through the polarizing section 82.

[0274] In the second HUD device 2, the polarization section 82 transmits the light contained in the projection light 40 that vibrates in a specific direction.

[0275] In the second HUD device 2, projection light 40 is shone from the image unit 31.

[0276] The projection light 41, after being transmitted through the polarization section 82, is irradiated onto the fourth principal surface 124, forming a reflected image on the fourth principal surface 124. The viewer 35 observes a virtual image 421 based on the reflected image formed on the fourth principal surface 124, located on the extension line of the light path 42.

[0277] The plane containing the light-emitting point 32 of the image unit 31, the reflection point 33 of the projection light 41 reflected on the fourth main surface 124, and the viewpoint 34 of the viewer 35 is the incident surface.

[0278] The direction of light vibration is not particularly limited for the projection light 40 emitted from the imaging unit 31. However, in order to increase the amount of light vibrating in a specific direction transmitted from the polarization unit 82, it is desirable to include light vibrating in a direction parallel to the transmission axis of the polarization unit 82.

[0279] The projected light vibrating in a specific direction becomes transmitted light that passes through the second glass plate, and reflected light that is reflected from the interior side of the second glass plate. The vibration direction of the projected light vibrating in a specific direction transmitted from the polarization section becomes the following vibration direction θ after passing through the second glass plate. α .

[0280] In a vehicle, the imaging unit 31 is preferably located on the vehicle's dashboard.

[0281] By changing the direction of the projection light 40 illuminating the image unit 31 or moving the position of the image unit 31, the position of the projection light 40 can be moved.

[0282] If a portion of the projection light 41 transmitted from the polarization section 82 is not reflected at the fourth principal surface 124, but is transmitted through the fourth principal surface 124, then the vibration direction of the projection light 41 advancing in the projection section changes by passing through the phase difference film 100.

[0283] The phase retardation film 100 has a tilt of θ relative to the X-axis in the projection plane. r The optical axis, if the angle between the incident plane and the X-axis in the projection plane is set as θ. pIn the case where the projection light 41 passes through the second glass plate 12 and enters the projection surface, the vibration direction θ α In the projection plane, it becomes 2θ r -θ p The direction of the projected light, after passing through the phase difference film 100, is rotated by 2dθ as described above, becoming a direction parallel to the incident plane, i.e., the same vibration direction as the P-polarized light.

[0284] The following description, with reference to the accompanying drawings, explains the change in the vibration direction of the projection light 41.

[0285] Figure 6 This is a schematic diagram illustrating the vibration direction of light incident on the phase retardation film 100 in the second HUD device. Furthermore, Figure 6 This shows the viewer looking forward (from the fourth principal plane side to the first principal plane side).

[0286] exist Figure 6 In this context, the X-axis is represented as 0°.

[0287] The angle between the optical axis of the phase retardation film and the X-axis is θ. r Here, θ is represented by 45°. r .

[0288] The vibration direction of P-polarized light is parallel to the incident plane, while the vibration direction of S-polarized light is perpendicular to the incident plane.

[0289] Let dθ be the angle between the vibration direction of the projection light 41 and the optical axis of the retardation film. When the projection light 41 passes through the retardation film, the vibration direction of the projection light rotates by 2dθ. That is, the vibration direction of the projection light 41 rotates 2dθ clockwise or counterclockwise in the attached figure. Through this rotation, the vibration direction of the projection light 41 is made parallel to the incident surface.

[0290] Under these conditions, the projected light 41 becomes P-polarized light by passing through the phase difference film.

[0291] Let θ be the direction of vibration of the projected light incident on the projection surface that satisfies this condition. α .

[0292] θ α It can be obtained in the following way.

[0293] The angle of the incident plane relative to the X-axis is Figure 6 θ p The angle indicated.

[0294] according to Figure 6 dθ=θ p -θ r ...Formula (1)

[0295] according to Figure 6 θ α =θ r -dθ···Equation (2)

[0296] According to equations (1) and (2) above, θ α =2θ r -θ p

[0297] When equation (1) is +, Figure 6 The vibration direction rotates counterclockwise, and when the above equation (1) is -, it rotates clockwise.

[0298] That is, when θ is satisfied α =2θ r -θ p When the projected light 41 enters the phase difference film, the vibration direction of the light after passing through the phase difference film becomes parallel to the incident surface.

[0299] Before the projection light enters the phase retardation film 100, the vibration direction θ of the projection light is adjusted. α Satisfying θ α =2θ r -θ p This prevents light from other vibrational directions that cause ghosting from entering the phase difference film.

[0300] The projection light, which becomes P-polarized light after passing through the phase difference film 100, is not reflected on the first principal surface 111, and the projection light is emitted to the outside in the state of P-polarized light.

[0301] In this way, for projected light that is not reflected on the fourth principal surface 124, as long as the reflection on the first principal surface 111 can be suppressed, the generation of ghosting can be suppressed.

[0302] Furthermore, in the second HUD device, the polarization section 82 is preferably movable, capable of changing the vibration direction of the light transmitted from the polarization section 82.

[0303] If the polarization section 82 is movable, then when the incident surface changes, moving the polarization section 82 can change the vibration direction of the light transmitted from the polarization section 82, and thus change the vibration direction θ of the projected light incident on the projection surface. α With satisfying θ α =2θ r -θ p The direction is consistent. Since the polarization part 82 is movable, even if the projection position is changed, the vibration direction θ of the projection light incident on the projection surface can be easily adjusted. α With satisfying θ α =2θ r -θ pThe orientation is consistent, so it is suitable for use as an S-HUD device.

[0304] [Example of the orientation of the transmission axis of the polarization section]

[0305] Next, examples of the orientation of the transmission axis of the polarization section of the first HUD device and the second HUD device will be described. Furthermore, the HUD device of the present invention is not limited to the examples listed below.

[0306] In the following example, the viewer is seated in the driver's position of a right-hand drive vehicle.

[0307] The area in front of the viewer is the area in front of the viewer. Any area away from the area in front of the viewer along any direction along the X-axis is defined as the area diagonally in front of the viewer.

[0308] Figure 7 This is a diagram that schematically illustrates an example of the relationship between the viewer, the position of the projection section, and the orientation of the transmission axis of the polarizing section in a first HUD device.

[0309] exist Figure 7 In the photo, spectator 35 is seated in the driver's seat of a right-hand drive vehicle.

[0310] Figure 7 The image 621L projected onto the left side of the viewer in front of the viewer, and the orientation of the transmission axis of the polarizing unit 81L used when viewing the image 621L, are shown. Furthermore, the image 621R projected onto the right side of the viewer in front of the viewer, and the orientation of the transmission axis of the polarizing unit 81R used when viewing the image 621R, are shown.

[0311] The orientation of the transmission axis of the polarizing section is adjusted when the viewer is viewing each image.

[0312] If it is the area directly in front of the viewer, then Figure 7 The orientation of the transmission axis of the polarization section is along the Z-axis. This is used as a reference line and is shown as a dashed line in the polarization section 81L and polarization section 81R.

[0313] In contrast, the transmission axes of polarization sections 81L and 81R are solid lines shown in polarization sections 81L and 81R.

[0314] exist Figure 7 In some cases, for example, in the polarizing section 81L located to the left of the viewer, the transmission axis is rotated counterclockwise on a plane along the XZ plane. On the other hand, in the polarizing section 81R located to the right of the viewer, the transmission axis is rotated clockwise. It is sufficient to adjust the angle at which the transmission axis is rotated to minimize ghosting. Furthermore, it is preferable to adjust the transmission axis so that it is parallel to the incident plane.

[0315] In addition, Figure 7 Since the transmission axis is located on the Z-axis, the orientation along the Z-axis is used as a reference, while in... Figure 8 In the case where the transmission axis is located on the X-axis, the orientation along the X-axis direction will be used as a reference.

[0316] Figure 8 This is a diagram that schematically illustrates an example of the relationship between the viewer, the position of the projection section, and the orientation of the transmission axis of the polarizing section in a second HUD device.

[0317] exist Figure 8 In the photo, spectator 35 is seated in the driver's seat of a right-hand drive vehicle.

[0318] Figure 8 The image 421L projected onto the left side of the viewer in front of the viewer, and the orientation of the transmission axis of the polarizing unit 82L used when viewing image 421L, are shown. Furthermore, the image 421R projected onto the right side of the viewer in front of the viewer, and the orientation of the transmission axis of the polarizing unit 82R used when viewing image 421R, are shown.

[0319] The orientation of the transmission axis of the polarizing section is adjusted when the viewer is viewing each image.

[0320] If it is the area directly in front of the viewer, then Figure 8 The orientation of the transmission axis of the polarization section is along the X-axis. This is used as a reference line and is shown as a dashed line in the polarization section 82L and polarization section 82R.

[0321] In contrast, the transmission axes of polarization sections 82L and 82R are the solid lines shown in polarization sections 82L and 82R.

[0322] exist Figure 8 In some cases, for example, in the polarizing section 82L located to the left of the viewer, the transmission axis is rotated clockwise on a plane along the XZ plane. On the other hand, in the polarizing section 82R located to the right of the viewer, the transmission axis is rotated counterclockwise.

[0323] Simply adjust the angle that causes the transmission axis to rotate to the angle that minimizes ghosting.

[0324] In addition, Figure 7 and Figure 8 An example is shown where the optical axis of the retardation film is 45°. However, sometimes the direction in which the transmission axis is rotated is set to be opposite to the above direction, depending on the angle of the optical axis, which can further suppress ghosting.

[0325] [Optional]

[0326] The aforementioned HUD device is particularly suitable for projecting images onto a car's windshield, but it can also project images onto the car's side windows. When projecting images onto the side windows, simply place a phase difference film on the side window, define the Y-axis as the direction horizontal to the ground and orthogonal to the direction the moving object is traveling, and define the X-axis as the direction horizontal to the ground and the direction the moving object is traveling. The projection light is then irradiated in the same manner as with the windshield.

[0327] [Examples of situations with multiple viewers]

[0328] The HUD device of the first embodiment of the present invention can employ a head-up display device such that, when there are multiple viewers, when multiple viewers see the image displayed in the central area of ​​the windshield from an oblique direction, the generation of ghosting can be suppressed from any viewer's angle.

[0329] The following explains how to suppress ghosting when the viewer consists of two people: the driver in the driver's seat of a right-hand drive vehicle and the passenger in the front passenger seat.

[0330] The driver's and passenger's respective frontal areas are the viewer's frontal areas. Areas away from the viewer's frontal areas in any direction along the X-axis are defined as the viewer's oblique frontal areas. Furthermore, areas away from the aforementioned viewer's frontal areas along both the X-axis and Z-axis are also defined as the viewer's oblique frontal areas.

[0331] The projection light is projected onto a central area, which is between the areas directly in front of the driver and passenger, and is equivalent to the area diagonally in front of the driver and passenger, respectively.

[0332] Figure 9 This diagram schematically illustrates an example of the relationship between the position of the viewer, the projection section, and the orientation of the transmission axis of the polarizing section in a first HUD device with multiple viewers.

[0333] exist Figure 9 In the first HUD device 1 shown, the driver 35D and passenger 35P, as viewers, see the image 621C projected onto the central area.

[0334] In addition, Figure 9 It shows one like 621C, but it can also display multiple.

[0335] exist Figure 9 In the middle, an image unit (not shown) is provided for the driver 35D and the passenger 35P respectively. Each image unit projects projection light onto the projection unit (windshield surface) in such a way that the image 621C overlaps in the central area.

[0336] In a vehicle, it is preferable to configure multiple imaging units in the vehicle's dashboard to accommodate multiple viewers.

[0337] Furthermore, polarizing units 81D and 81P are respectively provided for the driver 35D and the passenger 35P. The polarizing units 81D and 81P are positioned between the image unit and the projection unit corresponding to the driver 35D and the passenger 35P, respectively.

[0338] In the vehicle, the polarization section 81D and polarization section 81P are arranged in the instrument panel in the same way as the imaging section described above, and are preferably arranged adjacent to the light source so that light from the light source is quickly transmitted from the polarization section 81D or polarization section 81P.

[0339] The polarizing section 81D has a transmission axis that transmits projection light that vibrates in a direction parallel to the incident surface of the driver 35D, and the polarizing section 81P has a transmission axis that transmits projection light that vibrates in a direction parallel to the incident surface of the passenger 35P.

[0340] The orientation of the transmission axis of polarizing section 81D is different from that of polarizing section 81P.

[0341] Specifically, Figure 9 The polarizing unit 81D is oriented in a direction that is counterclockwise, using the case where the polarizing unit is facing the viewer and ...

[0342] The orientation of the transmission axis of polarizing section 81D and the orientation of the transmission axis of polarizing section 81P are adjusted in accordance with the positional relationship between the incident surface and the projection surface set for each viewer. In this way, a head-up display device can be made such that, when multiple viewers (drivers and passengers) are viewing the image displayed in the central area of ​​the windshield at an angle, ghosting can be suppressed regardless of the viewing angle.

[0343] Figure 10 This diagram schematically illustrates an example of the relationship between the position of the viewer, the projection section, and the orientation of the transmission axis of the polarizing section in a second HUD device with multiple viewers.

[0344] exist Figure 10 In the second HUD device 2 shown, the driver 35D and passenger 35P, as viewers, see the image 421C projected onto the central area.

[0345] An incident surface is provided for both the driver (35D) and passenger (35P). Furthermore, polarizing portions 82D and 82P are provided for both the driver (35D) and passenger (35P).

[0346] The polarization section 82D is configured such that the angle of the optical axis of the phase retardation film is set to θ. r Let θ be the angle between the incident plane and the X-axis in the projection plane for the driver 35D. p In the case of the projection light transmitted from the polarization section 82D and incident on the projection surface, the vibration direction θ α Satisfying θ α =2θ r -θ p .

[0347] Furthermore, the polarization section 82P is configured such that the angle of the optical axis of the phase retardation film is set to θ. r Let θ be the angle between the incident plane and the X-axis in the projection plane for passenger 35P. p In the case of the projected light transmitted from the polarization section 82P and incident on the projection surface, the vibration direction θ α Satisfying θ α =2θ r -θ p .

[0348] The orientation of the transmission axis of polarizing section 82D is different from that of polarizing section 82P.

[0349] Specifically, Figure 10 The polarizing unit 82D is oriented clockwise, taking the orientation of the transmission axis along the XY plane as a reference line when the area in front of the viewer is in front of them. The polarizing unit 82P is oriented counterclockwise, taking the orientation of the transmission axis along the XY plane as a reference line when the area in front of the viewer is in front of them.

[0350] The orientation of the transmission axis of polarizing section 82D and the orientation of the transmission axis of polarizing section 82P are adjusted in accordance with the positional relationship between the incident surface and the projection surface set for each viewer. In this way, a head-up display device can be made such that, when multiple viewers (drivers and passengers) are viewing the image displayed in the central area of ​​the windshield at an angle, ghosting can be suppressed regardless of the viewing angle.

[0351] Head-up Display (HUD) System

[0352] The HUD system of the first embodiment of the present invention is a system capable of switching the vibration direction of light transmitted from the polarization section within a single system.

[0353] Moreover, this system is designed to be used as both a first HUD device and a second HUD device by changing the vibration direction of the light transmitted from the polarization section.

[0354] Specifically, it is possible to switch between (A) and (B) below.

[0355] (A) Make the vibration direction of the light incident on the second glass plate parallel to the incident surface.

[0356] (B) The phase retardation film is positioned in the vibration direction θ of the projection light incident on the projection surface. α With the angle between the incident light and the optical axis set to dθ, the vibration direction of the incident projection light is rotated by 2dθ, and the angle between the incident surface and the X-axis of the projection surface is set to θ. p In this case, the phase retardation film makes the vibration direction of the light transmitted from the second glass plate 2θ in the projection plane. r -θ p The direction.

[0357] In cases like (A) above, it is a P-HUD and can be used as a first HUD device.

[0358] In cases like (B) above, it is an S-HUD and can be used as a second HUD device.

[0359] In addition, the projection position of the projected light can be changed in the projection section.

[0360] In the case of the first HUD device, the polarization section has a transmission axis that transmits light that vibrates in a specific direction parallel to the incident surface.

[0361] Here, if the projection position changes, the incident surface changes.

[0362] When the incident plane changes, if the position of the polarization section remains unchanged, the vibration direction of the light transmitted from the polarization section shifts from a direction parallel to the incident plane. Therefore, after transmission from the polarization section, the proportion of non-P-polarized light increases, making it easier to produce ghosting.

[0363] Therefore, when the projection position changes, the polarization section is made movable in accordance with the projection position, changing the vibration direction of the projection light transmitted from the polarization section, so that the light vibrating in a direction parallel to the changed incident surface is transmitted.

[0364] Therefore, ghosting can be suppressed even when the projection position changes.

[0365] The same applies to the second HUD device; in accordance with changing the incident surface by changing the projection position, the polarization section and the transmission axis are made movable.

[0366] Specifically, the angle between the changed incident surface and the X-axis in the changed projection surface is set as θ. p In the case of a changed projection plane, it becomes 2θ. r -θ p The direction (the angle of the optical axis of the phase difference film is θ) r Light transmission.

[0367] Therefore, ghosting can be suppressed even when the projection position changes.

[0368] (An embodiment related to the first embodiment of the present invention)

[0369] The following experiment was conducted: the occurrence of ghosting was compared in the area in front of the viewer and in the area diagonally in front of the viewer, respectively, when the vibration direction of the light transmitted from the polarization section was changed.

[0370] First, the experimental results are shown using the first HUD device.

[0371] Figure 11 This is a schematic diagram illustrating the configuration of the first HUD device used in the embodiments and comparative examples.

[0372] Figure 12 This is a schematic diagram illustrating the experimental system in Example 1. Figure 13 This is a schematic diagram representing the experimental system in Comparative Example 1.

[0373] Prepared as Figure 11 The first HUD device shown is a square projection section of 150mm × 150mm for P-HUD mode. The optical axis of the phase retardation film in the first HUD device 1 is set to 45°.

[0374] like Figure 11 As shown, the imaging unit 31 is placed horizontally, and the vehicle laminated glass 10 is positioned relative to the imaging unit 31 at a Brewster angle of 57°.

[0375] By placing a polarizer as a polarizing part 81 on the imaging part 31, the polarizing part 81 is disposed between the imaging part 31 and the vehicle laminated glass 10.

[0376] Projected light is shone vertically upward from the image unit 31, and the viewer 35 observes a virtual image located on the extension line of the light path based on the reflected image of the first main surface 111.

[0377] The viewer's eye level is the same as the height of the laminated glass in the vehicle.

[0378] A tablet computer is used as the imaging unit 31, and a green grid image is displayed on the tablet computer. A polarizer is placed on the tablet computer and positioned directly below the laminated glass for vehicles.

[0379] In addition, to simulate a moving vehicle traveling at night, a black background panel 37 is provided on the other side of the vehicle's laminated glass 10 in the direction seen by the viewer 35.

[0380] like Figure 12 and Figure 13 As shown, the viewer's front is set as position 0 in the X-axis direction, and -200mm and -400mm positions are set on the left side as the observation point.

[0381] Additionally, the left side of the X-axis direction is designated as the "-" direction, and the right side as the "+" direction.

[0382] In Example 1, as Figure 12 As shown, in the area in front of the viewer (location 0 in the X-axis direction), the transmission axis of the polarizing unit 81 is set to 0° with the Y-axis direction as the reference line.

[0383] exist Figure 12 , Figure 13 And the following Figure 15 , Figure 16 In this context, the position of the polarizing part is represented by its position on the XY plane, and the position of the laminated glass for vehicles is represented by its position on the XZ plane.

[0384] At locations of -200mm and -400mm, which are in the area diagonally in front of the viewer, the transmission axis of the polarizing unit 81 is rotated counterclockwise. The rotation angles are set to +10° and +25°, respectively. For the rotation angle, the counterclockwise rotation direction is set as +, and the clockwise rotation direction is set as -.

[0385] The above experiment was conducted as follows: the position of the viewer 35 was fixed, and the position of the 150mm×150mm square projection part was shifted by -200mm in the X-axis direction. Then, the image part was shifted by -200mm in the X-axis direction. The polarization part was also shifted by -200mm in the X-axis direction in the same way, with the projection part and the image part arranged between them.

[0386] In Comparative Example 1, such as Figure 13 As shown, at all observation points, the transmission axis of the polarization section 81 is set to 0° with the Y-axis as the reference line.

[0387] Figure 14 These are photographs showing the virtual images seen in Example 1 and Comparative Example 1.

[0388] When comparisons were made at positions at the same distance from the viewer, it was confirmed that ghosting was suppressed at locations of -200mm and -400mm in front of the viewer in Example 1.

[0389] On the other hand, in Comparative Example 1, ghosting was observed at these locations, extending both horizontally and vertically.

[0390] Next, the experimental results using a second HUD device are shown.

[0391] The experimental system itself and Figure 11 The first HUD device shown is identical. The polarizer used in the second HUD device, which is polarizer 82, is used instead of polarizer 81. Furthermore, the viewer 35 observes a virtual image based on the reflected image on the fourth principal surface 124, located on the extension line of the optical path.

[0392] Figure 15 This is a schematic diagram illustrating the experimental system in Example 2. Figure 16 This is a schematic diagram representing the experimental system in Comparative Example 2.

[0393] like Figure 15 and Figure 16 As shown, the viewer's front is set as position 0 in the X-axis direction, and -200mm and -400mm positions are set on the left side as the observation point.

[0394] Additionally, the left side of the X-axis direction is designated as the "-" direction, and the right side as the "+" direction.

[0395] In Example 2, as Figure 15 As shown, in the area in front of the viewer (the location at position 0 in the X-axis direction), the transmission axis of the polarizing unit 82 is set to 0° with the X-axis direction as the reference line.

[0396] At locations of -200mm and -400mm, which are in the area diagonally in front of the viewer, the transmission axis of the polarizing unit 82 is rotated clockwise. The rotation angles are set to -15° and -20°, respectively. For the rotation angle, the counterclockwise direction is set as + and the clockwise direction is set as -.

[0397] The above experiment was conducted as follows: the position of the viewer 35 was fixed, and the position of the 150mm×150mm square projection part was shifted by -200mm in the X-axis direction. Then, the image part was shifted by -200mm in the X-axis direction. The polarization part was also shifted by -200mm in the X-axis direction in the same way, with the projection part and the image part arranged between them.

[0398] In Comparative Example 2, such as Figure 16As shown, at all observation points, the transmission axis of the polarization section 82 is set to 0° with the X-axis direction as the reference line.

[0399] Figure 17 These are photographs showing the virtual images seen in Example 2 and Comparative Example 2.

[0400] When comparisons were made at positions at the same distance from the viewer, it was confirmed that in Example 2, ghosting was suppressed at locations of -200mm and -400mm in front of the viewer.

[0401] On the other hand, in Comparative Example 2, ghosting was observed at these locations, extending both horizontally and vertically.

[0402] (Second Implementation)

[0403] The head-up display device (HUD device), phase difference film, laminated glass for vehicles, and head-up display system (HUD system) according to the second embodiment of the present invention will be described with reference to the accompanying drawings.

[0404] Furthermore, as a HUD device according to the second embodiment of the present invention, there are HUD devices having an image unit that illuminates projection light with a vibration direction in the X direction, and HUD devices having an image unit that illuminates projection light with a vibration direction parallel to the YZ plane; these are referred to as a third HUD device and a fourth HUD device, respectively. In the description of the head-up display device according to the second embodiment of the present invention, without distinguishing between the third HUD device and the fourth HUD device, it is simply referred to as the HUD device according to the second embodiment of the present invention.

[0405] Furthermore, the HUD system according to the second embodiment of the present invention is a system that can be used as both a third HUD device and a fourth HUD device by switching the type of projected light irradiated in one system.

[0406] Furthermore, the phase retardation film according to the second embodiment of the present invention is a phase retardation film that can be used in the vehicle laminated glass, HUD device, and HUD system according to the second embodiment of the present invention. Furthermore, the vehicle laminated glass according to the second embodiment of the present invention is a vehicle laminated glass that can be used in the HUD device and HUD system according to the second embodiment of the present invention.

[0407] First, the phase difference film according to the second embodiment of the present invention will be described, and then the laminated glass for vehicles according to the second embodiment of the present invention will be described.

[0408] Next, the HUD device according to the second embodiment of the present invention will be described, and finally the HUD system according to the second embodiment of the present invention will be described.

[0409] [Phase difference film]

[0410] The second embodiment of the present invention relates to a phase retardation film that is an integral phase retardation film having a vertical axis in the up-down direction and a horizontal axis in the left-right direction. The characteristic is that at multiple locations along the vertical axis, the angle between the optical axis of the phase retardation film and the horizontal axis is fixed, and along the horizontal axis, the angle between the optical axis of the phase retardation film and the horizontal axis changes with a fixed tendency.

[0411] In the second embodiment of the present invention, the optical axis of the retardation film refers to the axis in which the refractive index of the retardation film is the largest.

[0412] Furthermore, the phase difference film in the second embodiment of the present invention is a 1 / 2 wavelength film (half-wavelength film).

[0413] Figure 18 This is a diagram schematically illustrating an example of a phase retardation film according to a second embodiment of the present invention.

[0414] exist Figure 18 The optical axis of the retardation film at various locations on the retardation film 201 is schematically shown. Furthermore, the orientations of the "horizontal axis" and "vertical axis" are shown.

[0415] exist Figure 18 At point P1, the angle between the optical axis of the phase difference film and the horizontal axis is 45°.

[0416] Furthermore, the angle between the optical axis and the horizontal axis of the retardation film is determined to be the smaller angle among the angles formed by the intersection of the two straight lines. When the optical axis and the horizontal axis of the retardation film are parallel, the angle between the optical axis and the horizontal axis of the retardation film is set to 0°.

[0417] At multiple locations along the vertical axis, namely P1, P2, and P3, the angle between the optical axis of the phasing film and the horizontal axis is fixed at 45°.

[0418] In the retardation film according to the second embodiment of the present invention, the angle between the optical axis of the retardation film and the horizontal axis varies with a fixed tendency along the horizontal axis direction.

[0419] exist Figure 18 The image shows a phase retardation film in which the angle between the optical axis and the horizontal axis of the phase retardation film changes continuously along the horizontal axis.

[0420] exist Figure 18The phase difference film 201 shown includes N1 and O1, which are located on the left side of the horizontal axis starting from point P1, and Q1 and R1, which are located on the right side of the horizontal axis starting from point P1.

[0421] exist Figure 18 At various locations from left to right, the angle between the optical axis of the phase retardation film and the horizontal axis is 35° at N1, 40° at O1, 45° at P1, 50° at Q1, and 55° at R1. Thus, it can be seen that the angle between the optical axis of the phase retardation film and the horizontal axis varies with a fixed tendency along the horizontal axis.

[0422] Furthermore, since the angle between the optical axis and the transverse axis of the phasor film changes continuously, for example, between locations O1 and P1, in Figure 18 The angle between the optical axis and the horizontal axis of the phase difference film at various locations from left to right changes continuously from 40° to 45°.

[0423] Figure 19 This is a diagram schematically illustrating an example of another phase retardation film according to the second embodiment of the present invention.

[0424] exist Figure 19 The image shows a phase retardation film in which the angle between the optical axis and the horizontal axis of the phase retardation film changes discontinuously along the horizontal axis.

[0425] exist Figure 19 In the phase retardation film 202 shown, a region p1 is depicted near the center of its horizontal axis, where the angle between the optical axis of the phase retardation film and the horizontal axis is 45°. The width of the p1 region is indicated on the phase retardation film 202 by a double-headed arrow.

[0426] In region p1, the optical axis of the phase retardation film forms the same angle with the transverse axis, which is 45°.

[0427] exist Figure 19 The phase difference film 202 shown includes regions n1 and o1 located on the left side along the horizontal axis starting from region p1, and regions q1 and r1 located on the right side along the horizontal axis starting from region p1.

[0428] exist Figure 19 The boundaries of each region are indicated by dashed lines.

[0429] The optical axis of the phase difference film in each region forms the same angle with the horizontal axis.

[0430] exist Figure 19In each region from left to right, the angle between the optical axis and the horizontal axis of the phase retardation film is 35° in region n1, 40° in region o1, 45° in region p1, 50° in region q1, and 55° in region r1. Thus, it can be seen that along the horizontal axis, the angle between the optical axis and the horizontal axis of the phase retardation film tends to change with a fixed tendency.

[0431] Furthermore, since the angle between the optical axis and the horizontal axis of the retardation film is the same in all regions, it can be concluded that the angle between the optical axis and the horizontal axis of the retardation film changes discontinuously.

[0432] Furthermore, the description up to this point has described a retardation film at a location or region where the angle between the optical axis and the horizontal axis of the retardation film is 45°. However, the specific value of the angle between the optical axis and the horizontal axis of the retardation film is not limited to the range of the examples described above. Any retardation film in which the angle between the optical axis and the horizontal axis of the retardation film changes with a fixed tendency along the horizontal axis direction is considered a retardation film according to the second embodiment of the present invention. Furthermore, when the angle between the optical axis and the horizontal axis of the retardation film changes discontinuously, the magnitude of the angle change between adjacent regions is not limited to 5°. Moreover, the magnitude of the angle change between adjacent regions may not be fixed.

[0433] As a phase retardation film, it is possible to use a phase retardation element formed by uniaxial or biaxial stretching of plastic films such as polycarbonate, polyarylate, polyethersulfone, cyclic olefin polymer, triacetyl cellulose, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN), or a phase retardation element that fixes the orientation state by orienting the liquid crystal polymer in a specific direction.

[0434] The former, a phase retardation element formed by uniaxial or biaxial stretching of a plastic film, can utilize films produced by methods such as solvent casting and melt extrusion. Solvent casting involves dissolving a polymer resin in a solvent, coating it onto a smooth surface such as stainless steel strip or polyethylene terephthalate (PET), allowing the solvent to evaporate, and then winding the film. Melt extrusion involves heating and melting a polymer resin in an extruder, extruding it through a slit (T-die), cooling it, and then winding the film. For stretching, a stretching machine is generally used, which can obtain phase retardation films stretched in longitudinal, transverse, and oblique directions.

[0435] As the latter phase difference element, a phase difference element can be used, for example, by heat-treating and cooling a transparent substrate such as polyethylene terephthalate (PET) or triacetyl cellulose (TAC) after orientation treatment to fix the liquid crystal orientation.

[0436] Examples of the aforementioned liquid crystal polymers are not particularly limited to compounds that exhibit liquid crystal properties such as nematic liquid crystals, twisted nematic liquid crystals, discoid liquid crystals, and cholesteric liquid crystals when oriented in a specific direction. For example, compounds that undergo twisted nematic orientation in the liquid crystal state and become glassy below the liquid crystal transition point can be used, including main-chain liquid crystal polymers such as optically active polyesters, polyamides, polycarbonates, and polyesterimides, and side-chain liquid crystal polymers such as optically active polyacrylates, polymethacrylates, polymalonides, and polysiloxanes. Furthermore, polymer compositions in which other low- or high-molecular-weight optically active compounds are added to these non-optically active main-chain or side-chain polymers can be used as examples.

[0437] Examples of alignment treatment methods include rubbing the surface of a plastic film serving as a transparent substrate, or forming an organic thin film (alignment film) such as polyimide on a glass plate or plastic film and then rubbing or photoaligning the alignment film. As a rubbing treatment, methods can be employed such as wiping the surface of the plastic film or alignment film using rubbing cloths such as nylon or rayon.

[0438] As a coating method for liquid crystal polymers, commonly known methods such as spin coating, die coating, spray coating, calendering coating, and gravure coating can be used.

[0439] Furthermore, a phase retardation film with a discontinuously varying angle between its optical axis and transverse axis can be fabricated by stacking or bonding multiple phase retardation films at an angle with different optical axes in each region.

[0440] Figure 18 The phase difference film 201 shown Figure 19 The phase difference film 202 shown can be used to obtain the vehicle laminated glass according to the second embodiment of the present invention, the HUD device according to the second embodiment of the present invention, and the HUD system according to the second embodiment of the present invention.

[0441] That is, by using the phase difference film according to the second embodiment of the present invention, it is possible to provide a HUD device with a wide display area in the lateral direction of the windshield surface.

[0442] Laminated glass for vehicles

[0443] The second embodiment of the present invention relates to a laminated glass for vehicles having a first glass plate, a second glass plate, and a phase difference film disposed between the first glass plate and the second glass plate, characterized in that the phase difference film is the phase difference film according to the second embodiment of the present invention.

[0444] Figure 20This is an exploded perspective view schematically illustrating an example of a laminated glass for vehicles according to a second embodiment of the present invention.

[0445] The first glass panel has a first main surface exposed on the outdoor side and a second main surface on the opposite side of the first main surface.

[0446] In addition, the second glass panel has a fourth main surface exposed on the indoor side and a third main surface on the opposite side of the fourth main surface.

[0447] Figure 20 Laminated glass 210 for vehicles is shown.

[0448] Figure 20 The diagram shows a second glass plate 12 positioned near the front of the image, with the surface visible from the front being the fourth main surface 124. The surface opposite the fourth main surface 124 is the third main surface 123.

[0449] A first glass plate 11 is disposed on the inner side of the attached drawing, and the surface visible from the front is the second main surface 112. The surface opposite to the second main surface 112 is the first main surface 111.

[0450] A first glass plate 11 and a second glass plate 12 are disposed between them. Figure 18 The phase difference film 201 is described in the text.

[0451] Since the fourth main surface 124 is the surface exposed on the interior side, it becomes the surface directly seen by the viewer when the vehicle is fitted with laminated glass. That is, in Figure 20 The image shows the positional relationships as seen directly from inside the vehicle.

[0452] The laminated glass 210 used in this vehicle is a right-hand drive vehicle laminated glass, and the viewer who sees the HUD image is the driver. The position of the phasing film 201 was determined in a way that the point where the optical axis of the phasing film forms an angle of 45° with the horizontal axis is in front of the viewer as the driver in a right-hand drive vehicle.

[0453] Furthermore, on the left side of the viewer, the angle between the optical axis and the horizontal axis is smaller than 45°, while on the right side of the viewer, the angle between the optical axis and the horizontal axis is larger than 45°.

[0454] exist Figure 20 The diagram shows a case where the optical axis is tilted to the upper right in front of the viewer, with an angle of 45° between the optical axis and the horizontal axis. However, it is also possible for the optical axis to be tilted to the upper left in front of the viewer, with an angle of 45° between the optical axis and the horizontal axis. When the optical axis is tilted to the upper left in front of the viewer, the angle between the optical axis and the horizontal axis is larger than 45° on the left side of the viewer, and smaller on the right side of the viewer.

[0455] Furthermore, when the optical axis is tilted to the upper left, the angle between the optical axis and the horizontal axis is set to an acute angle that indicates the value of the complementary angle of the obtuse angle, since the angle is obtuse in the same method of obtaining the angle as when the optical axis is tilted to the upper right.

[0456] In laminated glass for vehicles, it is preferable that the first and second glass sheets are bonded together as a single unit via an interlayer. The interlayer is a film that bonds the first and second glass sheets together by heating it to a temperature at which the polymer constituting the interlayer softens. Therefore, polymers such as polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), acrylic resin (PMMA), polyurethane resin, polyethylene terephthalate (PET), and cyclic olefin polymers (COP) can be used. Alternatively, the interlayer may also consist of multiple resin layers.

[0457] The phase retardation film is disposed between the first glass plate and the second glass plate.

[0458] The phase retardation film can be disposed inside the intermediate film, or at the position where it is in contact with the first glass plate, or at the position where it is in contact with the second glass plate.

[0459] By aligning the lateral direction of the first and second glass plates with the transverse direction of the phase difference film, it is possible to form a laminated glass for vehicles that serves as a windshield.

[0460] As a glass material constituting laminated glass for vehicles, materials that can be processed from flat glass sheets into curved shapes are suitable. Besides soda-lime silicate glass as specified in ISO 16293-1, known glass materials such as aluminosilicate glass, borosilicate glass, and alkali-free glass can also be used as the glass sheet material. The thickness of each of the first and second glass sheets can be, for example, set to 0.4 mm to 3 mm. Furthermore, the spacing between the first and second glass sheets can be set to 0.05 mm to 1 mm.

[0461] exist Figure 20 The configuration shown is Figure 18 The phase retardation film 201 described herein is used in laminated glass for vehicles; however, the use of... Figure 19 The phase retardation film 202 described herein, as a phase retardation film for laminated glass for vehicles, is also a laminated glass for vehicles according to the second embodiment of the present invention.

[0462] The laminated glass for vehicles according to the second embodiment of the present invention can be used to obtain the HUD device and the HUD system according to the second embodiment of the present invention.

[0463] That is, by using the laminated glass for vehicles according to the second embodiment of the present invention, it is possible to provide a HUD device having a wide display area in the lateral direction of the windshield surface.

[0464] Furthermore, similar to the windshield, the area for displaying the HUD image can be expanded by using the aforementioned vehicle-grade laminated glass in the side windows. Preferably, the projection area where the projected light is projected is positioned further forward than the viewer's direct side.

[0465] Head-up display (HUD)

[0466] In the HUD device according to the second embodiment of the present invention, there are two types: a third HUD device and a fourth HUD device. First, the definitions of the X-axis, Y-axis, and Z-axis, the definition of the moving body, and examples of the moving body, which are common to both HUD devices, are the same as those of the HUD device and moving body according to the first embodiment of the present invention.

[0467] As a vehicle laminated glass used in HUD devices, the vehicle laminated glass according to the second embodiment of the present invention can be used.

[0468] [Third HUD device]

[0469] The third HUD device is a device that observes the reflected image formed on the fourth principal surface of the second glass plate as a virtual image; it is an S-HUD type HUD device.

[0470] Figure 21 This is a summary of a third HUD device according to the first aspect of the second embodiment of the present invention, and a schematic diagram of the optical path in the device.

[0471] This diagram shows a cross-section of the viewer's frontal area, with the viewer positioned as the driver. The X-axis is perpendicular to the plane of the paper.

[0472] exist Figure 21 In the diagram, the light path of the projected light is represented by a solid line.

[0473] In the third HUD device 3, the projection unit is a vehicle laminated glass 210, which has a first glass panel 11 disposed on the outdoor side of the vehicle, which is a moving body, and a second glass panel 12 disposed on the indoor side of the vehicle.

[0474] The first glass panel 11 has a first main surface 111 exposed on the outdoor side and a second main surface 112 on the opposite side of the first main surface 111.

[0475] In addition, the second glass panel 12 has a fourth main surface 124 exposed on the indoor side and a third main surface 123 on the opposite side of the fourth main surface 124.

[0476] A phase difference film 201 is disposed between the first glass plate 11 and the second glass plate 12.

[0477] Projected light 240 shines from the image unit 31 onto the fourth principal surface 124, forming a reflected image on the fourth principal surface 124. The viewer 35 observes a virtual image 412 located on the extension line of the light path 241 based on the reflected image formed on the fourth principal surface 124.

[0478] In the third HUD device 3, projection light 240 with the vibration direction in the X-axis direction is irradiated from the image unit 31.

[0479] Here, the plane containing the light-emitting point 32 of the image unit 31, the reflection point 33 of the projection light 240 reflected on the fourth main surface 124, and the viewpoint 34 of the viewer 35 is the incident surface.

[0480] exist Figure 21 In this context, the paper surface is roughly the same as the incident surface.

[0481] Light whose vibration direction is perpendicular to the incident plane is S-polarized light. When the incident plane is perpendicular to the X-axis, and projection light with the vibration direction along the X-axis is incident onto the incident plane, the projection light is S-polarized light.

[0482] When the projection light is S-polarized, the projection light that passes through the fourth principal surface 124 and advances within the projection section is converted into P-polarized light by passing through the phase difference film 201. It does not reflect on the first principal surface 111 and is emitted to the outdoor side while maintaining the state of P-polarized light.

[0483] If the reflection on the first principal surface 111 can be suppressed in this way, the generation of ghosting can be suppressed.

[0484] When a viewer views a reflected image formed in the area in front of the viewer, the phase retardation film disposed in the area in front of the viewer is such that, in a plane parallel to the fourth principal plane, the optical axis of the phase retardation film is at 45°±5° relative to the X-axis.

[0485] If the optical axis of the retardation film 201, which transmits S-polarized light along the vibration direction of the X-axis, is at 45°±5° relative to the X-axis, the proportion of S-polarized light converted into P-polarized light increases. Since the incident surface in the region in front of the viewer is perpendicular to the X-axis, and the projected light is S-polarized, the generation of ghosting can be suppressed by making the optical axis of the corresponding retardation film at 45°±5° relative to the X-axis.

[0486] Next, the situation of a viewer viewing a reflected image formed in the area diagonally in front of the viewer will be explained. The area diagonally in front of the viewer is the area away from the viewer's frontal area in any direction along the X-axis.

[0487] When the viewer is looking at an area diagonally in front of them, the incident surface differs from when the viewer is looking at an area directly in front of them. Because the vibration direction of the projected light remains along the X-axis, the vibration direction (X-axis) of the projected light relative to the incident surface shifts from the vertical direction. The projected light becomes a mixture of S-polarized and P-polarized light, and the further away from the area directly in front of the viewer, the higher the proportion of P-polarized light.

[0488] For such mixed light, if the optical axis of the phase retardation film is kept at 45°±5° relative to the X-axis, the proportion of P-polarized light in the projected light after passing through the phase retardation film will decrease, resulting in a higher proportion of S-polarized light.

[0489] Therefore, when a viewer is viewing a reflected image formed in the region diagonally in front of the viewer, for a phase retardation film arranged in the region diagonally in front of the viewer, by shifting the optical axis of the phase retardation film from 45°±5° relative to the X-axis, the proportion of the component that becomes P-polarized light increases after the mixed light of S-polarized light and P-polarized light passes through the phase retardation film, thereby suppressing the generation of ghosting.

[0490] In either the region directly in front of the viewer or the region diagonally in front of the viewer, by directing the projected light into a phase retardation film, the vibration direction of the projected light is converted to a direction parallel to the incident plane. Light with a vibration direction parallel to the incident plane is P-polarized light.

[0491] When the projected light passing through the phase retardation film is P-polarized, it is not reflected on the first principal surface, and the projected light remains P-polarized as it is emitted towards the outside. Therefore, ghosting can be suppressed in either the area in front of the viewer or the area diagonally in front of the viewer, making it a HUD device capable of suppressing ghosting even when the display area of ​​the HUD is laterally expanded by the windshield surface.

[0492] Figure 22 This diagram schematically illustrates the positions of the area in front of the viewer and the area diagonally in front of the viewer when the driver is the viewer in a right-hand drive vehicle.

[0493] exist Figure 22 The image shows only the vehicle-mounted laminated glass 210 constituting the HUD device, and also schematically shows the direction of the optical axis of the phase retardation film constituting the vehicle-mounted laminated glass 210.

[0494] Since the right side of the vehicle laminated glass 210 in the attached diagram is located in front of the viewer 35 in a right-hand drive vehicle, a viewer front area 250 is provided in this part. In the viewer front area 250, the optical axis of the phasing film is 45°±5° relative to the X-axis.

[0495] The area to the right of the viewer's frontal area 250 along the X-axis is the right peripheral area 251. On the other hand, the area to the left of the viewer's frontal area 250 along the X-axis is the left peripheral area 252.

[0496] In the right peripheral region 251, the optical axis ratio of the retardation film is offset by a direction of 50° relative to the X-axis. On the other hand, in the left peripheral region 252, the optical axis ratio of the retardation film is offset by a direction of 40° relative to the X-axis.

[0497] That is, in the right peripheral region and the left peripheral region, the direction in which the optical axis of the phase difference film is offset from the X-axis at 45°±5° is opposite.

[0498] The same applies when the passenger in the front seat of a left-hand drive vehicle is a spectator.

[0499] Figure 23 It is a diagram schematically showing the positions of the area in front of the viewer and the area diagonally in front of the viewer in a left-hand drive vehicle.

[0500] Since the left side of the vehicle laminated glass 210 in the attached diagram is located in front of the viewer 35 in a left-hand drive vehicle, a viewer front area 250 is provided in this part. In the viewer front area 250, the optical axis of the phasing film is 45°±5° relative to the X-axis.

[0501] and Figure 22 Similarly, the area to the right of the viewer's frontal area 250 along the X-axis is the right peripheral area 251, and the area to the left of the viewer's frontal area 250 along the X-axis is the left peripheral area 252.

[0502] In the right peripheral region 251, the optical axis ratio of the retardation film is offset by a direction of 50° relative to the X-axis. On the other hand, in the left peripheral region 252, the optical axis ratio of the retardation film is offset by a direction of 40° relative to the X-axis.

[0503] That is, in the right peripheral region and the left peripheral region, the direction in which the optical axis of the phase difference film is offset from the X-axis at 45°±5° is opposite.

[0504] The same applies when the passenger in the front seat of a right-hand drive vehicle is a spectator.

[0505] Figure 24 This is a diagram illustrating, in a way that shows the positions of the viewer's frontal area and the viewer's diagonally forward area in a right-hand drive vehicle where the driver is the viewer.

[0506] The direction of the optical axis of the phase retardation film and Figure 22 The methods shown are different. Figure 22 In the manner shown, the optical axis is tilted to the upper right in front of the viewer, with the angle between the optical axis and the horizontal axis being 45°. Figure 24 In the manner shown, the light axis is tilted to the upper left in front of the viewer, and the angle between the light axis and the horizontal axis is 45°.

[0507] In the right peripheral region 251, the optical axis ratio of the retardation film is shifted in a direction that is smaller than 40° relative to the X-axis. On the other hand, in the left peripheral region 252, the optical axis ratio of the retardation film is shifted in a direction that is larger than 50° relative to the X-axis.

[0508] That is, in the right peripheral region and the left peripheral region, the direction in which the optical axis of the phase difference film is offset from the X-axis at 45°±5° is opposite.

[0509] The same applies when the passenger in the front seat of a left-hand drive vehicle is a spectator.

[0510] Figure 25 This is a diagram illustrating, in a left-hand drive vehicle, the positions of the area in front of the viewer and the area diagonally in front of the viewer in a situation where the driver is the viewer.

[0511] The direction of the optical axis of the phase retardation film and Figure 23 The methods shown are different. Figure 23 In the manner shown, the optical axis is tilted to the upper right in front of the viewer, with the angle between the optical axis and the horizontal axis being 45°. Figure 25 In the manner shown, the light axis is tilted to the upper left in front of the viewer, and the angle between the light axis and the horizontal axis is 45°.

[0512] In the right peripheral region 251, the optical axis ratio of the retardation film is shifted in a direction that is smaller than 40° relative to the X-axis. On the other hand, in the left peripheral region 252, the optical axis ratio of the retardation film is shifted in a direction that is larger than 50° relative to the X-axis.

[0513] That is, in the right peripheral region and the left peripheral region, the direction in which the optical axis of the phase difference film is offset from the X-axis at 45°±5° is opposite.

[0514] The same applies when the passenger in the front seat of a right-hand drive vehicle is a spectator.

[0515] Figure 26 This diagram schematically illustrates the positions of the area in front of the viewer and the area diagonally in front of the viewer when the viewer consists of a driver and a passenger in the front seat.

[0516] In this method, the driver and the passenger in the front seat each see different images.

[0517] For each viewer, the angle between the optical axis of the phase retardation film and the X-axis is optimized in the region in front of the viewer and in the region diagonally in front of the viewer.

[0518] When the viewers are the driver and the passenger in the front seat, relative to being... Figure 26 The viewer 35 shown on the right side of the driver is provided with a viewer front area 250, and a right peripheral area 251 is provided in the area away from the viewer front area 250 on the right side along the X-axis direction.

[0519] Furthermore, relative to being Figure 26 The viewer 35′ of the passenger seat shown on the left has a viewer front area 250′, and a left peripheral area 252′ is provided in the area away from the viewer front area 250′ on the left along the X-axis.

[0520] In addition, Figure 26 In this context, we assume a right-hand drive vehicle with the driver's seat on the right and the passenger seat on the left, but the same applies even to left-hand drive vehicles with the driver's seat on the left and the passenger seat on the right.

[0521] exist Figure 26 In the shown configuration, the left peripheral area relative to the viewer 35 as the driver and the right peripheral area relative to the viewer 35′ as the passenger are not provided. However, these areas may be provided depending on the configuration of the projection section relative to the viewer 35 as the driver and the projection section relative to the viewer 35′ as the passenger.

[0522] In addition, multiple screens can be combined in a way that allows each viewer to see the projected light. Figure 20 The phase difference film shown.

[0523] Figure 27 This is a diagram illustrating, in a schematic way, the positions of the area in front of the viewer and the area diagonally in front of the viewer when there are two occupants, the driver and the front passenger.

[0524] The direction of the optical axis of the phase retardation film and Figure 26 The methods shown are different. Figure 26 In the manner shown, the optical axis is tilted to the upper right in front of the viewer, with the angle between the optical axis and the horizontal axis being 45°. Figure 27 In the manner shown, the light axis is tilted to the upper left in front of the viewer, and the angle between the light axis and the horizontal axis is 45°.

[0525] In the right peripheral region 251 relative to the viewer 35 who is the driver, the optical axis of the phasing film is offset by a smaller 40° relative to the X-axis. On the other hand, in the left peripheral region 252' relative to the viewer 35' who is the passenger, the optical axis of the phasing film is offset by a larger 50° relative to the X-axis.

[0526] The area in front of the viewer can be extended to the area in front of the viewer in the side window glass arranged to the side of the viewer, and the projection part can also be extended to the side window glass.

[0527] Figure 28 This diagram schematically illustrates how the projection section is extended into the side window glass.

[0528] exist Figure 28 The image shows a side window 270 positioned on the right side of the vehicle laminated glass 210. A viewer can see the projected light projected onto the right-side side window 270.

[0529] The area in the side window glass 270 where the projected light is projected is set as the right extended area 271.

[0530] Even in the right extended region 271, the angle of the optical axis of the phase retardation film varies in the right peripheral region of the viewer's frontal area.

[0531] Even when the area diagonally in front of the viewer is extended to the extended area of ​​the side window glass, the same idea can be used to suppress the occurrence of ghosting.

[0532] [Fourth HUD device]

[0533] The fourth HUD device is a device that observes the reflected image formed on the first main surface of the first glass plate as a virtual image; it is a P-HUD type HUD device.

[0534] Figure 29 This is an outline of a fourth HUD device according to a second aspect of a second embodiment of the present invention, and a schematic diagram of the optical path in the device.

[0535] This diagram shows a cross-section of the viewer's frontal area, with the viewer positioned as the driver. Furthermore, the paper surface is parallel to the YZ plane.

[0536] exist Figure 29 In the diagram, the light path of the projected light is represented by a solid line.

[0537] In the fourth HUD device 4, the projection unit is a vehicle laminated glass 210, which has a first glass panel 11 disposed on the outdoor side of the vehicle, which is a moving body, and a second glass panel 12 disposed on the indoor side of the vehicle.

[0538] The first glass panel 11 has a first main surface 111 exposed on the outdoor side and a second main surface 112 on the opposite side of the first main surface 111.

[0539] In addition, the second glass panel 12 has a fourth main surface 124 exposed on the indoor side and a third main surface 123 on the opposite side of the fourth main surface 124.

[0540] A phase difference film 201 is disposed between the first glass plate 11 and the second glass plate 12.

[0541] In the fourth HUD device 4, projection light 260 with a vibration direction parallel to the YZ plane is irradiated from the image unit 31.

[0542] Here, the plane containing the light-emitting point 32 of the image unit 31, the reflection point 33 where the projected light 260 is reflected from the first main surface 111, and the viewpoint 34 of the viewer 35 is the incident surface.

[0543] exist Figure 29 In this context, the paper surface is roughly the same as the incident surface.

[0544] Light whose vibration direction is parallel to the incident plane is P-polarized light. When the incident plane is parallel to the YZ plane, and projection light whose vibration direction is parallel to the YZ plane is incident on the incident plane, the projection light is P-polarized light.

[0545] When the projected light 260 is P-polarized light, it can be used even in sunglasses mode when viewing a virtual image through polarized sunglasses.

[0546] Projection light 260 shines from image unit 31 onto fourth main surface 124. The projection light advancing in the projection unit is converted into S-polarized light by phase difference film 201, forming a reflected image on first main surface 111. The S-polarized light that is not reflected passes through first main surface 111 and is emitted to the outside while maintaining the state of S-polarized light.

[0547] The reflected image formed on the first principal surface 111 passes through the phase retardation film 201 again and is converted into P-polarized light. The viewer 35 views a virtual image 612 based on the reflected image on the first principal surface 111, located on the extension line of the optical path 261.

[0548] Since the virtual image 612 is composed of P-polarized light, the viewer 35 can see the virtual image even through polarized sunglasses 36.

[0549] Furthermore, no reflected image is formed on the fourth principal plane 124, or only a small amount of reflected image is formed. When the intensity of the reflected image formed on the fourth principal plane 124 is relatively stronger than that of the reflected image formed on the first principal plane 111, the reflected image formed on the fourth principal plane 124 is observed as a ghost image.

[0550] When a viewer views a reflected image formed in the region in front of the viewer, the phase retardation film disposed in the region in front of the viewer is such that the optical axis of the phase retardation film is at 45°±5° relative to the X-axis in a plane parallel to the fourth principal plane.

[0551] In the area directly in front of the viewer, the projected light is almost entirely P-polarized. If the optical axis of the phase retardation film 201 through which the P-polarized light is transmitted in the area directly in front of the viewer is at 45°±5° relative to the X-axis, then a greater proportion of the P-polarized light is converted into S-polarized light.

[0552] If the efficiency of converting the projected light (P-polarized light) incident on the phase retardation film into S-polarized light increases, the virtual image display based on the reflected image formed on the first principal surface of the first glass plate becomes stronger. Therefore, the influence of the reflected image formed on the fourth principal surface becomes relatively weaker, and the occurrence of ghosting can be suppressed.

[0553] Next, the situation of a viewer viewing a reflected image formed in the area diagonally in front of the viewer will be explained. The area diagonally in front of the viewer is the area away from the viewer's frontal area in any direction along the X-axis.

[0554] When the viewer is looking at an area diagonally in front of them, the incident surface differs from when the viewer is looking at an area directly in front of them. Because the vibration direction of the projected light remains parallel to the YZ plane, the vibration direction of the projected light relative to the incident surface (the direction parallel to the YZ plane) shifts from parallel. The projected light becomes a mixture of S-polarized and P-polarized light, and the further away from the area directly in front of the viewer, the higher the proportion of S-polarized light.

[0555] For such mixed light, if the optical axis of the phase retardation film is kept at 45°±5° relative to the X-axis, the proportion of S-polarized light in the projected light after passing through the phase retardation film will decrease, resulting in a higher proportion of P-polarized light.

[0556] Therefore, when a viewer views a reflected image formed in the region obliquely in front of the viewer, for the phase retardation film arranged in the region obliquely in front of the viewer, by shifting the optical axis of the phase retardation film from 45°±5° relative to the X-axis, the proportion of the component that becomes S-polarized light increases after the mixed light of S-polarized light and P-polarized light passes through the phase retardation film, thereby strengthening the display of the virtual image based on the reflected image formed on the first main surface of the first glass plate.

[0557] Since the virtual image based on the reflected image formed on the first principal surface is strengthened, the influence of the projected light reflected on the fourth principal surface is relatively weakened, thus suppressing the generation of ghosting.

[0558] In either the region directly in front of the viewer or the region diagonally in front of the viewer, by directing the projected light into a phase retardation film, the vibration direction of the projected light is converted to a direction perpendicular to the incident plane. Light with a vibration direction perpendicular to the incident plane is S-polarized light.

[0559] When the projected light after passing through the phase retardation film is S-polarized light, the reflection of the first principal surface becomes stronger. Therefore, the virtual image display based on the reflected image formed on the first principal surface of the first glass plate becomes stronger.

[0560] Therefore, ghosting can be suppressed in either the area in front of the viewer or the area diagonally in front of the viewer. Even when the display area of ​​the HUD is expanded laterally by the windshield, it still becomes a HUD device that can suppress ghosting.

[0561] The fourth HUD device can also determine the positions of the viewer's frontal area and the viewer's diagonally forward area in the same way as the third HUD device. Examples of the positions of the viewer's frontal area and the viewer's diagonally forward area for right-hand drive and left-hand drive vehicles can be found by referring to... Figure 22 and Figure 23 As explained.

[0562] Furthermore, an example where the optical axis of the retardation film is tilted to the upper left can be referenced. Figure 24 and Figure 25 As explained.

[0563] Furthermore, examples of situations where there are two viewers can be referenced. Figure 26 and Figure 27 As explained.

[0564] Furthermore, an example of extending the projection unit into the side window glass can be referred to as Figure 28 As explained.

[0565] Furthermore, the third and fourth HUD devices described above both illustrate a device where the tilt of the optical axis of the phase refraction film in the region diagonally in front of the viewer is a continuous change along the X-axis (i.e., using...). Figure 18 The example shown is a retardation film. However, it is also possible to use a device where the change in the tilt of the optical axis of the retardation film in the region diagonally in front of the viewer is discontinuous along the X-axis (i.e., using a device that...). Figure 19 (Example of a phase difference film shown).

[0566] Head-up Display (HUD) System

[0567] The HUD system of the second embodiment of the present invention is a system that can be used as a third HUD device or a fourth HUD device by switching the type of projected light that is irradiated in one system.

[0568] In a HUD system, the imaging unit can switch and illuminate a first projection light with a vibration direction along the X-axis and a second projection light with a vibration direction parallel to the YZ plane.

[0569] When illuminated by the first projection light, it functions as an S-HUD and can be used as a third HUD device. When illuminated by the second projection light, it functions as a P-HUD and can be used as a fourth HUD device.

[0570] It is used as a fourth HUD device when the viewer sees a virtual image through polarized sunglasses or other polarizing filters.

[0571] The structure outside the image unit in the HUD system can adopt the same structure as the third and fourth HUD devices.

[0572] The following explains the switching between the first projection light and the second projection light in the imaging unit.

[0573] The imaging unit can be a device capable of projecting a first projection light whose vibration direction is in the X-axis direction, or it can be a device capable of projecting a second projection light whose vibration direction is in the direction parallel to the YZ plane.

[0574] In addition, it can be a device with two projection mechanisms and the ability to switch between different types of projection light.

[0575] Alternatively, it can be a device in which a certain polarized light is initially irradiated, and a polarization control unit is arranged in the optical path of the light, thereby enabling the projected light to be converted into a first projection light or a second projection light.

[0576] Examples of types of projected light before conversion include light that randomly contains any polarization (unpolarized light), circularly polarized light or elliptically polarized light, mixed light of P-polarized and S-polarized light, and linearly polarized light that is neither P-polarized nor S-polarized.

[0577] As an imaging department, a projector capable of illuminating projection light is suitable. Examples of such projectors include DMD projection system projectors, laser scanning MEMS projection system projectors, and reflective liquid crystal projectors.

[0578] For example, if the imaging unit has a mechanism that initially illuminates a first projection light whose vibration direction is the X-axis direction, by setting a half-wave plate (a phase difference film whose optical axis is 45° relative to the vibration direction of the first projection light) as a polarization control unit in the optical path of the projection light, the first projection light can be converted into a second projection light.

[0579] As long as the first projection light is used directly as the projection light and does not pass through the polarization control unit, but is used as the second projection light and passes through the polarization control unit.

[0580] By controlling whether the light passes through or not through the polarization control unit, the first projection light and the second projection light can be switched.

[0581] In the case where the imaging unit has a mechanism that initially illuminates a second projection light whose vibration direction is parallel to the YZ plane, the second projection light can be converted into a first projection light by using the same structure. Therefore, by controlling the passage / non-passage of the polarization light control unit, the switching between the second projection light and the first projection light can be performed.

[0582] In the fourth HUD device, the reflected image formed on the first main surface of the first glass plate is observed as a virtual image. However, when the intensity of the projected light is the same as that of the third HUD device, the virtual image is weaker compared to the reflected image formed on the fourth main surface of the second glass plate in the third HUD device.

[0583] Therefore, it is preferable to set the illumination intensity when projecting the second projection light to be higher than the illumination intensity when projecting the first projection light. This can be achieved by switching the illumination intensity of the projection light illuminating the image unit between the first and second projection lights. Alternatively, the illumination intensity can be reduced by allowing the first projection light to pass through an ND filter or the like.

[0584] (An embodiment related to the second embodiment of the present invention)

[0585] The following experiment was conducted: the occurrence of ghosting was compared when the angle between the optical axis of the phase difference film and the X-axis changed in the area in front of the viewer and the area diagonally in front of the viewer.

[0586] First, the experimental results are shown for the case where the area diagonally in front of the viewer is located to the viewer's right.

[0587] Figure 30 This is a schematic diagram illustrating the configuration of the third HUD device used in the embodiments and comparative examples.

[0588] Figure 31 This is a schematic diagram illustrating the experimental system in Example 3. Figure 32This is a schematic diagram representing the experimental system in Comparative Example 3.

[0589] Prepared as Figure 30 The third HUD device shown is a square projection section of 200mm × 200mm for S-HUD mode.

[0590] like Figure 30 As shown, the imaging unit 31 is placed horizontally, and the vehicle laminated glass 210 is positioned relative to the imaging unit 31 at a positional relationship forming a Brewster angle of 56°.

[0591] Projected light vibrating in the X-axis direction is shone vertically upward from the imaging unit 31, and the viewer 35 observes the virtual image displayed on the fourth main surface 124. The viewer's viewpoint is at the same height as the laminated glass used in the vehicle.

[0592] A tablet computer is used as the imaging unit 31, and a white grid image is displayed on the tablet computer. The tablet computer is positioned directly below the laminated glass of the vehicle.

[0593] In addition, to simulate a moving vehicle traveling at night, a black background panel 37 is provided on the other side of the vehicle's laminated glass 210 in the direction seen by the viewer 35.

[0594] like Figure 31 and Figure 32 As shown, the viewer's front is set as position 0 in the X-axis direction, and +200mm and +400mm positions are set on the right side.

[0595] In Example 3, as Figure 31 As shown, in the area directly in front of the viewer (position 0 in the X-axis direction), a projection unit is arranged with the optical axis of the retardation film at a 45° angle to the X-axis. Furthermore, at positions +200mm and +400mm, which are in the area diagonally in front of the viewer, projection units are arranged with the optical axis of the retardation film at 55° and 65° angles to the X-axis, respectively.

[0596] The above experiment was conducted as follows: the position of the projection part of the 200mm×200mm square was shifted by 200mm in turn, and then the projection part was tilted so that the optical axis of the phase difference film was tilted.

[0597] In Comparative Example 3, such as Figure 32 As shown, at all observation points, the projection section is arranged with the optical axis of the phase retardation film at a 45° angle relative to the X-axis.

[0598] Figure 33 These are photographs showing the virtual images seen in Example 3 and Comparative Example 3.

[0599] When comparisons were made at positions at the same distance from the viewer, it was confirmed that in Example 3, ghosting was suppressed at locations of +200mm and +400mm, which are located in the area diagonally in front of the viewer.

[0600] On the other hand, in Comparative Example 3, a ghosting effect extending laterally was observed at these locations.

[0601] Next, experimental results are shown for cases where the area diagonally in front of the viewer is located to the left of the viewer.

[0602] Figure 34 This is a schematic diagram illustrating the experimental system in Example 4. Figure 35 This is a schematic diagram illustrating the experimental system in Comparative Example 4. The experimental method was the same as in Example 3.

[0603] like Figure 34 and Figure 35 As shown, the viewer's front is set as position 0 in the X-axis direction, and -100mm, -200mm, -300mm, -400mm, and -500mm positions are set on the left side.

[0604] like Figure 34 As shown, in Embodiment 4, in the area in front of the viewer (location 0 in the X-axis direction), the optical axis of the retardation film is made at 45° relative to the X-axis. At locations of -100mm, -200mm, -300mm, -400mm, and -500mm, which are areas diagonally in front of the viewer, the optical axis of the retardation film is made at 40°, 35°, 30°, 25°, and 20° relative to the X-axis, respectively.

[0605] like Figure 35 As shown, in Comparative Example 4, the optical axis of the phase retardation film was made at 45° relative to the X-axis at all observation points.

[0606] Figure 36 These are photographs showing the virtual images seen in Example 4 and Comparative Example 4.

[0607] When comparisons were made at positions at the same distance from the viewer, it was confirmed that in Example 4, ghosting was suppressed at locations of -100mm, -200mm, -300mm, -400mm, and -500mm, which are located in the area diagonally in front of the viewer.

[0608] On the other hand, in Comparative Example 4, particularly at the -300mm, -400mm, and -500mm locations, a ghosting effect extending laterally was observed.

[0609] [Industry availability]

[0610] A HUD device can be provided that can suppress ghosting when a viewer is viewing an image displayed in the area near the outer periphery of the windshield of a vehicle such as a car at an angle.

[0611] This application claims priority under the Paris Convention and the laws of the countries in which they are entered, based on Japanese Patent Application No. 2020-022342 filed on February 13, 2020, Japanese Patent Application No. 2020-027920 filed on February 21, 2020, and Japanese Patent Application No. 2020-140713 filed on August 24, 2020. The entire contents of these applications are incorporated herein by reference.

[0612] Explanation of reference numerals in the attached figures

[0613] 1: The first HUD device;

[0614] 2: Second HUD device;

[0615] 3: Third HUD device;

[0616] 4: Fourth HUD device;

[0617] 10, 210: Laminated glass for vehicles;

[0618] 11: First glass plate;

[0619] 12: Second glass plate;

[0620] 20: Vehicles;

[0621] 31: Imaging Department;

[0622] 32: Light-emitting point;

[0623] 33: Reflection point;

[0624] 34: Viewpoint;

[0625] 35: The viewer;

[0626] 35D: Driver (Viewer);

[0627] 35P: Passengers (viewers);

[0628] 36: Polarized sunglasses;

[0629] 40, 60: Projected light;

[0630] 41: Projected light after transmission from the polarization section;

[0631] 42, 241: The optical path based on the reflected image formed on the fourth principal plane;

[0632] 61: Projected light after transmission from the polarization section;

[0633] 62, 261: The optical path based on the reflected image formed on the first principal surface;

[0634] 81, 81L, 81R, 81D, 81P, 82, 82L, 82R, 82D, 82P: Polarization section;

[0635] 100, 201, 202: Phase retardation films;

[0636] 111: First main face;

[0637] 112: Second main face;

[0638] 123: The third main face;

[0639] 124: The fourth main face;

[0640] 240: Projected light with vibration direction in the X-axis direction;

[0641] 250, 250′: The viewer's frontal area in the second embodiment;

[0642] 251: Right peripheral area (the area diagonally in front of the viewer in the second embodiment);

[0643] 252, 252′: Left peripheral area (the area diagonally in front of the viewer in the second embodiment);

[0644] 260: Projected light whose vibration direction is parallel to the YZ plane;

[0645] 270: Side window glass;

[0646] 271: Right-side extended area;

[0647] 412, 421, 421C, 421L, 421R: Virtual image (a virtual image located on the extension of the optical path based on the reflected image formed on the fourth principal plane);

[0648] 612, 621, 621C, 621L, 621R: Virtual image (a virtual image located on the extension of the optical path based on the reflected image formed on the first principal surface).

Claims

1. A head-up display device mounted on a moving body, which causes a viewer who is an occupant of the moving body to view a virtual image based on a reflection image of projection light at a projection portion, characterized by comprising: an image portion that radiates the projection light; a polarization portion that is provided as a member different from the image portion between the image portion and the projection portion, and transmits light included in the projection light that vibrates in a specific direction; and the projection portion that is projected with the projection light transmitted from the polarization portion, wherein the projection portion is a laminated glass in which a second glass plate, a phase difference film, and a first glass plate are sequentially arranged from an indoor side that is an incident side of the projection light to an outdoor side, the projection portion has a viewer front region that is a front of the viewer and a viewer oblique front region that is a region away from the viewer front region in either direction of the X axis, the projection light is projected at least to the viewer oblique front region, when the X axis is set to 0° when the projection portion is viewed from the viewer, and a surface along the phase difference film is set to a projection surface, and the projection portion is a surface that is a reflection surface of the projection light, and the viewer views a virtual image based on a reflection image formed on an indoor side surface of the second glass plate.

2. The head-up display device according to claim 1, wherein the viewer observes a virtual image based on a reflection image formed on the indoor side surface of the second glass plate.

3. The head-up display device according to claim 1, wherein the viewer is a plurality of people, the polarization portion is provided between the image portion and the projection portion for each viewer, and each of the polarization portions has an incident surface that is set for each viewer, and each of the polarization portions transmits the projection light that vibrates in the specific direction corresponding to the incident surface.

4. The head-up display device according to claim 3, wherein the polarization portion has a transmission axis in which a vibration direction of the projection light that is transmitted becomes the specific direction, and the transmission axis of each of the polarization portions is different.

5. The head-up display device according to claim 4, wherein the projection light is projected to a central region that is a region corresponding to the viewer oblique front region of each of the plurality of viewers between the viewer front regions of each of the plurality of viewers.

6. The head-up display device according to claim 3, wherein the transmission axis of each of the polarization portions is adjusted in accordance with a positional relationship between the incident surface and the projection surface.

7. The head-up display device according to claim 1, wherein the projection position at which the projection light is projected in the projection portion is changeable, and the polarization portion is movable in accordance with a change in the incident surface accompanying a change in the projection position, and a vibration direction of light transmitted from the polarization portion is changeable. ​ ​ ​ The phase difference film has an optical axis inclined by θ r with respect to an X axis in the projection surface, and is a phase difference film that rotates a vibration direction of the projection light by 2dθ when an angle formed by the vibration direction θ α of the projection light incident into the projection surface and the optical axis is set as dθ. In a case where an angle of the incident surface with respect to an X axis in the projection surface is set as θ p , the vibration direction θ α r is a direction of 2θ r − θ p in the projection surface. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 8. The head-up display device according to claim 1, wherein the phase difference film is partially disposed.

9. A head-up display system mounted on a moving body, which causes a viewer who is an occupant of the moving body to view a virtual image based on a reflected image of projection light at a projection portion, characterized by when a direction orthogonal to a ground level and to a direction of advance of the moving body when advancing is set as an X axis, a direction orthogonal to the ground level and to the direction of advance of the moving body when advancing is set as a Y axis, a direction orthogonal to the ground is set as a Z axis, and a plane having a viewpoint of the viewer, a light emission point of the projection light, and a reflection point which is a point at which the projection light is reflected is set as an incidence plane, the head-up display system has: an image portion which irradiates the projection light; a polarization portion which is provided between the image portion and the projection portion as a member different from the image portion, transmits light contained in the projection light which vibrates in a specific direction; and the projection portion which is projected with the projection light, the projection portion is a laminated glass in which a second glass plate, a phase difference film, and a first glass plate are sequentially disposed from an indoor side which is an incident side of the projection light to an outdoor side, the projection portion has a viewer front region which is a front of the viewer and a viewer oblique front region which is a region away from the viewer front region in either direction of the X axis, the projection light is projected at least to the viewer oblique front region, when the X axis when the projection portion is viewed from the viewer is set as 0° and a plane along the phase difference film is set as a projection plane, The phase difference film has an optical axis inclined by θ r with respect to an X axis in the projection surface, and is a phase difference film that changes a vibration direction of the projection light incident on the projection surface through the optical axis. the polarization portion is movable, and by changing a vibration direction of light transmitted from the polarization portion, it is possible to switch between (A) and (B) below: (A) a vibration direction of light incident on the second glass plate is made parallel to the incidence plane, (B) The phase retardation film is positioned in the vibration direction θ of the projected light incident on the projection surface. α With the angle between the incident light and the optical axis set to dθ, the vibration direction of the incident projection light is rotated by 2dθ, and the angle between the incident surface and the X-axis in the projection surface is set to θ. p In this case, the phase retardation film causes the vibration direction of the light transmitted from the second glass plate to be 2θ in the projection plane. r −θ p The direction.

10. The head-up display system according to claim 9, wherein in the projection portion, a projection position at which the projection light is projected is changeable, corresponding to a change in the incidence plane accompanying a change in the projection position, the polarization portion is movable, and a vibration direction of the projection light transmitted from the polarization portion is changeable.

Images