JP7110575B2 - Video display device, vehicle - Google Patents

Description

The present invention relates to a video display device and a vehicle.

2. Description of the Related Art Conventionally, HUDs (head-up displays) installed in automobiles, ships, and the like use window glass used as a front window as a reflective display panel for displaying images. Window glass used in HUDs includes those in which an intermediate film with a wedge-shaped cross section is placed between two pieces of glass, those in which a prism sheet having a half-mirror surface is placed, and those in which a cholesteric liquid crystal layer is placed. are known in various forms.
Of these, a reflective display panel (front window) in which a cholesteric liquid crystal layer is arranged has recently attracted attention due to its wide viewing angle characteristics and the like (see, for example, Patent Document 1).

WO2015/125908

However, in such a reflective display panel, part of the image light transmitted through the cholesteric liquid crystal layer is reflected by the glass plate on the back side, and part of the image light is reflected on the reflective display panel (the glass plate on the viewer's side). Double images may occur due to reflection or the like at the time of incidence of light, and reduction of double images is a problem.

Patent Document 1 describes a projection system that is applied to a HUD and that includes a projection image display member having a cholesteric liquid crystal layer inside. In the projection system and the like of Patent Document 1, countermeasures are taken to display good images even in bright environments, but no countermeasures against such double images are disclosed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a video display device and a vehicle capable of displaying good video with reduced double images.

The present invention solves the above problems by means of the following solutions. In order to facilitate understanding, reference numerals corresponding to the embodiments of the present invention are used for explanation, but the present invention is not limited to these.
A first invention is a reflective display panel that has translucency and reflects at least part of projected image light to display an image, the reflective display panel having translucency and having a thickness of a first transparent substrate (122) provided on the incident side of the image light in the direction of the display panel; a substrate (127), a cholesteric liquid crystal layer (124) provided between the first transparent substrate and the second transparent substrate, and reflecting circularly polarized light in a predetermined wavelength region and in one rotational direction; 1. A reflective display panel (12, 22) comprising a reflection suppressing layer (121) laminated on an incident side surface of a transparent substrate.
A second aspect of the present invention is an image display comprising the reflective display panel (12, 22) of the first aspect and an image source (11) for projecting image light including at least circularly polarized light onto the reflective display panel. A device (10).
In a third aspect of the invention, in the image display device of the second aspect, the angle of incidence of the image light on the reflective display plate is θ1, and the light incident from the incident side is reflected by the antireflection layer and the first transparent substrate. The image display device (10) satisfies θ1−30°≦γ1≦θ1+30°, where γ1 is the incident angle of the light at which the reflected Y value is minimized.
In a fourth aspect of the invention, in the image display device of the second aspect or the third aspect, the cholesteric liquid crystal layer (124) is located between the first transparent substrate (122) and the second transparent substrate (127). An image display device (10) characterized by comprising a quarter-wave retardation layer (125) provided on the rear side of the image display device (10).
According to a fifth aspect of the present invention, in the image display device according to the fourth aspect, when the incident angle of the image light to the reflective display plate is θ1 and the light is incident on the interface between the second transparent substrate and the air from the air side, The image display device (10) satisfies β−20°≦θ1≦β+20°, where β is the Brewster angle of .
A sixth aspect of the invention is the video display device of the second aspect or the third aspect, comprising a second antireflection layer (228) laminated on the back side surface of the second transparent substrate (127), A video display device (10) characterized by:
In a seventh aspect based on the image display device according to the sixth aspect, the angle of incidence of image light on the reflective display plate is θ1, and the second antireflection layer (228) and the second transparent layer (228) for light incident from the back side A video display device (10) characterized by satisfying θ1−30°≦γ2≦θ1+30°, where γ2 is the incident angle of the light at which the reflection Y value of the reflected light on the substrate (127) is minimum. be.
An eighth invention is a vehicle comprising the video display device (10) according to any one of the second invention to the seventh invention, wherein the video source (11) is arranged inside the vehicle, The vehicle is characterized in that the reflective display panel (12) is a translucent part of the vehicle.

Advantageous Effects of Invention According to the present invention, it is possible to provide a video display device and a vehicle that can display good video with reduced double images.

It is a figure explaining the video display apparatus 10 of 1st Embodiment. 4A and 4B are diagrams for explaining the layer structure and the like of the window glass 12 (reflective display panel) of the first embodiment; FIG. 4A to 4C are diagrams showing an example of a method for manufacturing the window glass 12 (reflective display panel) of the first embodiment; FIG. FIG. 10 is a diagram for explaining the layer structure and the like of a window glass 22 (reflective display panel) according to a second embodiment; FIG. 10 is a diagram showing an example of a method for manufacturing the window glass 22 (reflective display panel) of the second embodiment; 1 is a diagram showing an automobile 30, which is a vehicle in which the image display device 10 of the first embodiment is arranged; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, each figure shown below including FIG. 1 is a schematic diagram, and the size and shape of each part are appropriately exaggerated for easy understanding.
In this specification, terms that specify shapes and geometric conditions, for example, terms such as parallel and orthogonal, have the same optical function and can be regarded as parallel or orthogonal in addition to the strict meaning. It shall include the state with an error of
In addition, numerical values such as dimensions and material names of each member described in this specification are examples as an embodiment, and are not limited to these, and may be appropriately selected and used.

In this specification, the terms plate and the like are used, but in view of the fact that the order of plate, sheet, and film is generally used in order of thickness, it is also used in this specification. i am using it. However, such proper use has no technical meaning, so these words can be replaced as appropriate. The same applies to terms such as layers and films.

(First embodiment)
FIG. 1 is a diagram illustrating a video display device 10 according to the first embodiment. FIG. 1(a) is a diagram for explaining the image display device 10 of the first embodiment, and FIG. 1(b) is a diagram for explaining an area A where an image is displayed on the front window of the first embodiment. be.
FIG. 6 is a diagram showing an automobile 30, which is a vehicle in which the image display device 10 of the first embodiment is arranged.
The image display device 10 of the present embodiment is a HUD (head-up display) that projects an image onto a front window or the like that serves as a translucent portion (window) of an automobile 30, and includes an image source 11 that projects image light L, an image and a window glass 12 which is a reflective display panel onto which light L is projected. In the present embodiment, the window glass 12 will be described by citing an example in which it is used as a front window of an automobile 30 .

The image source 11 projects image light L onto a predetermined area (for example, area A shown in FIG. 1B) of the window glass 12 (front window) in front of the driver's seat. At least part of the image light L is reflected by a cholesteric liquid crystal layer 124, which will be described later, in the window glass 12, and travels toward the viewer E side. Thereby, the observer E can visually recognize the image projected on the area A of the window glass 12 .
The image to be displayed can be appropriately selected from characters, graphics, etc. For example, display of the speed and direction of travel of the vehicle 30, weather, pedestrians, obstacles, approach of objects such as other vehicles, etc. The contents of the warning display, etc., may also be appropriately selected.

In this embodiment, as an example, the image source 11 is arranged on or within a dashboard (not shown) such as the driver's seat side of the automobile 30, and is positioned below the window glass 12 in the vertical direction. The image light L is projected obliquely upward toward 12 from below. This image source 11 projects circularly polarized light as image light. The image light L may contain a polarized component other than the circularly polarized light, but in that case, it is preferable that the proportion of the circularly polarized light is large.

In this embodiment, as shown in FIG. 1, the image source 11 projects the image light L toward the region A below the center of the window glass 12 in front of the driver's seat of the automobile 30 . The driver, who is the observer E, can view the image displayed by the image display device 10 while viewing the scenery outside the vehicle in the traveling direction through the window glass 12 .
In this embodiment, as an example, the image source 11 is provided with a quarter-wave retardation plate (not shown) at the projection opening of a projector such as an LCD system that emits linearly polarized light so that circularly polarized light can be projected. is used. Not limited to this, the image source 11 may be provided with a quarter-wave retardation plate (not shown) at the projection port of a laser light source or the like, and may use one that can project circularly polarized light, or a smartphone, tablet, or the like. A mobile terminal or the like that can display an image on a screen may be used.

FIG. 2 is a diagram for explaining the layer structure and the like of the window glass 12 (reflective display panel) of the first embodiment. FIG. 2 schematically shows a cross section parallel to the thickness direction of the window glass 12 .
The window glass 12 is a light-transmissive member arranged to cover the light-transmitting portion in front of the automobile 30, and is configured as laminated glass in which an intermediate layer or the like is sandwiched between two glass plates.
The window glass 12 is a reflective display panel that reflects at least part of the projected image light L to display an image. 122 , a first intermediate layer 123 , a cholesteric liquid crystal layer 124 , a quarter-wave retardation layer 125 , a second intermediate layer 126 and a second glass plate 127 .
2 and the like, the direction parallel to the thickness direction of the window glass 12 is the Z direction, the inside of the vehicle (observer side, incident side) is the +Z side, and the outside of the vehicle (back side) is the -Z side.

The first glass plate 122 is a translucent first transparent substrate disposed on the vehicle inner side (incident side) in the thickness direction of the window glass 12, and is a plate-like member made of glass.
The first intermediate layer 123 , the cholesteric liquid crystal layer 124 , the quarter-wave retardation layer 125 and the second intermediate layer 126 are sandwiched between the first glass plate 122 and the second glass plate 127 .
The first glass plate 122 is made of soda lime glass (blue plate glass), borosilicate glass (white plate glass), quartz glass, soda glass, potash glass, or the like. The first glass plate 122 has a thickness of, for example, about 2 to 3 mm.

The antireflection layer 121 is a layer laminated on the vehicle inner side (+Z side) of the first glass plate 122 . The antireflection layer 121 has a function of suppressing reflection when light enters or exits the interface between the window glass 12 and the air on the inside of the vehicle.
By laminating the reflection suppressing layer 121 on the vehicle interior side of the first glass plate 122 , reflection of the image light L incident on the window glass 12 can be suppressed. As a result, double images caused by reflection of part of the image light L when entering the window glass 12 can be reduced. Further, this increases the amount of image light incident on the window glass 12 and increases the amount of image light reflected by the cholesteric liquid crystal layer 124, which will be described later, so that a brighter and highly visible image can be displayed.

The antireflection layer 121 may have a multi-layer structure in which two or more layers having different refractive indices are laminated on the vehicle-inside (+Z side) surface 122a of the first glass plate 122 by vapor deposition, sputtering, or the like. Alternatively, a single layer structure or a multilayer structure formed by coating (applying) a layer having a refractive index lower than that of the first glass plate 122 on the surface 122a of the first glass plate 122 on the vehicle interior side may be employed.
The thickness of the antireflection layer 121 is optically determined from the above-described layer structure and the refractive index of the material forming each layer.
It should be noted that an antifouling layer (not shown) may be formed on the vehicle inner side (+Z side) of the antireflection layer 121 to reduce adhesion of dust, dirt, and the like. The antifouling layer preferably has a thickness of about 1 to 10 nm.

The first intermediate layer 123 is a layer laminated on the vehicle outer side (−Z side) of the first glass plate 122 . The first intermediate layer 123 bonds the first glass plate 122 and the cholesteric liquid crystal layer 124 together. Further, the first intermediate layer 123 has a function of preventing the first glass plate 122 from scattering when the window glass 12 is broken.
The first intermediate layer 123 is made of PVB (polyvinyl chloride), for example, and preferably has a thickness of about 0.3 to 0.8 mm. Note that the first intermediate layer 123 is not limited to PVB, and other resins such as COP (cycloolefin polymer) may be used.

The cholesteric liquid crystal layer 124 is a layer laminated on the vehicle outer side (−Z side) of the first intermediate layer 123, and has a function of reflecting at least part of the circularly polarized image light L incident on the window glass 12. .
The cholesteric liquid crystal layer 124 is a layer formed of a polymerizable liquid crystal material that becomes a cholesteric liquid crystal phase. It is provided by curing the liquid crystal by heating or the like and by fixing the turning direction of the liquid crystal.

The cholesteric liquid crystal layer 124 selectively reflects a circularly polarized component in a predetermined wavelength range determined by the helical pitch of the liquid crystal and in a direction of rotation that matches the direction of rotation of the liquid crystal. and a circularly polarized component in a direction opposite to the direction of rotation of the liquid crystal are transmitted. In this embodiment, the rotation direction of the liquid crystal of the cholesteric liquid crystal layer 124 matches the rotation direction of the circularly polarized image light L projected onto the window glass 12 .
Since the reflectance of the cholesteric liquid crystal layer 124 is not 100%, the image light L to be reflected (a predetermined wavelength range determined by the helical pitch of the liquid crystal and coincident with the rotation direction of the liquid crystal) ) is also transmitted through the cholesteric liquid crystal layer 124 .

The cholesteric liquid crystal layer 124 may be a single layer, or may have a multi-layer structure in which a plurality of liquid crystal layers are laminated. In addition, from the viewpoint of visibility, the cholesteric liquid crystal layer 124 preferably has high reflection characteristics for light with a wavelength of 550 nm or near (green light). preferably have reflective properties.
Therefore, when the cholesteric liquid crystal layer 124 is a single layer, it is preferable that the cholesteric liquid crystal layer 124 has a selected wavelength range in which light having a wavelength of at least 550 nm or a wavelength in the vicinity thereof is the central wavelength. Moreover, when the cholesteric liquid crystal layer 124 has a multilayer structure, it is preferable that the center wavelengths of the selected wavelength ranges of the respective liquid crystal layers are different.

As described above, the wavelength range of light reflected by the cholesteric liquid crystal layer 124 is determined by the helical pitch of the liquid crystal. It can be appropriately set by adjusting the amount of the chiral agent to be added. When the cholesteric liquid crystal layer 124 has a multilayer structure, it is possible by adjusting the amount of the chiral agent added to the polymerizable liquid crystal material of each liquid crystal layer.
In this embodiment, as shown in FIG. 2 and the like, image light is incident obliquely with respect to the normal direction of the surface of the cholesteric liquid crystal layer 124 and is reflected obliquely. The colors are shifted to shorter wavelengths. Therefore, the wavelength having the peak luminance of the reflected light visually recognized at the position of the observer E (for example, the wavelength having the peak luminance in the 45° specular reflection) is defined as the central wavelength of the selected wavelength range.

The quarter-wave retardation layer 125 is a layer arranged between the cholesteric liquid crystal layer 124 and the second intermediate layer 126, and the light passing through it is shifted by 1 in the vibration direction of the electric field (polarization plane). It is a layer having a function of producing a phase difference of /4 wavelengths. The quarter-wave retardation layer 125 is a so-called quarter-wave plate.
Most of the image light L projected from the image source 11 and incident on the window glass 12 is reflected by the cholesteric liquid crystal layer 124 as described above. It is incident on the four-wave retardation layer 125 . The image light (circularly polarized light) incident on the quarter-wave retardation layer 125 becomes linearly polarized light by passing through the quarter-wave retardation layer 125 . The quarter-wave retardation layer 125 is arranged such that the circularly polarized image light L is transmitted through the quarter-wave retardation layer 125 to enter the interface between the second glass plate 127 and the air as P-polarized light. , the direction of the slow axis, etc. are set. Although the details will be described later, this is to reduce the reflection of part of the image light at the interface between the window glass 12 and the air outside the vehicle. P-polarized light is polarized light in which an electric field oscillates within the plane of incidence, which is perpendicular to the interface (boundary plane) of different adjacent media and contains incident light and reflected light. In the present embodiment, the interface is the interface between the second glass plate 127 and the air (surface 127b of the second glass plate 127 on the vehicle exterior side).
Also, the ellipticity of the quarter-wave retardation layer 125 in the transmitted light is preferably close to 1, more preferably 1.

The quarter-wave retardation layer 125 is formed by, for example, forming an alignment film (not shown) on a film substrate (TAC (triacetylcellulose) or the like) having small optical anisotropy (not shown), and forming a liquid crystal on this alignment film. A member having a retardation layer that imparts a quarter-wave retardation to transmitted light by coating a material or the like may be used, or a COP or the like that is stretched so as to exhibit a predetermined optical anisotropy. oriented film material may be used. Further, not limited to this, forming an alignment film on a film with large optical anisotropy such as PET (polyethylene terephthalate), and further coating a liquid crystal material thereon to form a quarter wavelength retardation layer, The quarter-wave retardation layer 125 may be formed by removing the film having large optical anisotropy after transferring onto a film base material having small optical anisotropy. Further, as described above, after forming the quarter-wave retardation layer 125 by coating the liquid crystal material, it is directly bonded to the second glass plate 127 on which the second intermediate layer 126 is formed, and the optically anisotropic layer is formed. For example, large films may be excluded.

The second intermediate layer 126 is a layer laminated on the vehicle outer side (−Z side) of the quarter-wave retardation layer 125, and joins the quarter-wave retardation layer 125 and the second glass plate 127 to there is Further, the second intermediate layer 126 has a function of preventing the second glass plate 127 from scattering when the window glass 12 is broken.
The second intermediate layer 126 is made of the same material as the first intermediate layer 123 and has the same thickness.

The second glass plate 127 is a second transparent substrate arranged on the vehicle outer side (back side) of the first glass plate 122 in the thickness direction of the window glass 12, and is laminated on the vehicle outer side of the second intermediate layer 126. It is a plate-like member made of glass. It is a transparent member laminated on the vehicle outer side (−Z side) of the second intermediate layer 126 . The second glass plate 127 is made of the same material as the first glass plate 122 described above. The thickness of the second glass plate 127 is also the same as that of the first glass plate 122 described above.

Next, an example of a method for manufacturing the window glass 12, which is a reflective display panel, will be described.
FIG. 3 is a diagram showing an example of a method of manufacturing the window glass 12 (reflective display panel) of the first embodiment.
First, as shown in FIG. 3(a), an alignment film (photo-alignment film) (not shown) is formed on the PET substrate 101, and a polymerizable liquid crystal material is used to form a quarter-wave retardation layer 125 thereon. formed.
Next, as shown in FIG. 3(b), a polymerizable liquid crystal material containing a chiral agent is applied onto the quarter-wave retardation layer 125, cured by irradiation with ultraviolet rays, and specularly reflected at 45°. to form a cholesteric liquid crystal layer 124 having a peak luminance (central wavelength) of reflected light at a wavelength of 550 nm.
In the present embodiment, the cholesteric liquid crystal layer 124 has a peak luminance (central wavelength) of reflected light at a wavelength of 550 nm with regular reflection at 45°. may be appropriately set according to the use environment of the video display device 10 or the like.

Next, as shown in FIG. 3C, a first intermediate layer 123 formed by applying PVB as an adhesive to the laminate of the quarter-wave retardation layer 125 and the cholesteric liquid crystal layer 124 is formed. Then, the PET substrate 101 is peeled off.
Furthermore, as shown in FIG. 3(d), PVB as an adhesive is applied to the surface of the obtained laminate on the 1/4 wavelength retardation layer 125 side to form a second intermediate layer 126, This laminate and the second glass plate 127 are bonded together.
Next, as shown in FIG. 3(e), a reflection suppressing layer 121 is formed on the surface of the obtained laminate on the first glass plate 122 side to form the window glass 12 which is a reflective display plate. be.

Hereinafter, how the image light and the external light travel in the image display device 10 will be described with reference to FIG. 2 described above. 2 shows the image light L (L1 to L3) and the external light G (G1 to G3) traveling through the window glass 12. Although the refraction of light between layers is omitted, it is assumed that light is actually refracted appropriately between layers.
As described above, the image source 11 projects circularly polarized light onto the window glass 12 as the image light L1. At this time, the incident angle of the image light L1 to the window glass 12 is assumed to be θ1 (°).
In order to reduce double images caused by part of the image light L1 being reflected when the image light L1 is incident on the window glass 12, the first glass plate 122 is provided with the reflection suppression layer 121. is laminated, the incident angle γ1 (°) at which the reflection Y value of the light reflected from the reflection suppression layer 121 and the first glass plate 122 of the light incident from the inside of the vehicle (+Z side) is the minimum, and the window glass 12 It is preferable that the incident angle θ1 of the image light L1 to .theta.1 satisfies the following relationship.
θ1-30°≤γ1≤θ1+30°

This reflected Y value is the visible reflectance (%) of the CIE color system, and was measured using a UV-visible spectrophotometer V-7100 and an absolute reflectance measurement unit VAR-7010 manufactured by JASCO Corporation. In the absolute reflectance measurement, the specular reflectance at an incident angle of 5° to 70° was measured in 5° steps in the wavelength range of 380 nm to 780 nm. The reflection Y value is obtained by converting the specular reflectance of the object at each angle into the brightness perceived by the human eye (visible reflectance). The incident angle γ1 is the incident angle at which the reflection Y value is minimized.
The reason why it is preferable to satisfy the above relationship is as follows.

In order to reduce double images caused by reflection of part of the image light when the image light L1 is incident on the window glass 12, the image light L1 is transmitted through the antireflection layer 121 and the first glass plate 122. A high transmittance (low reflectance) is preferred.
Therefore, in a state in which the antireflection layer 121 is laminated on the vehicle interior side (+Z side) of the first glass plate 122, the reflection Y value of the light incident from the vehicle interior side on the reflection suppression layer 121 and the first glass plate 122 is is the minimum, and the incident angle θ1 of the image light L1 onto the window glass 12 is equal, the reflection of the image light L1 at the interface between the antireflection layer 121 and the first glass plate 122 is most suppressed. be. Further, the inventors of the present application have found that if the angle γ1 is within the range of θ1±30°, the effect of suppressing the reflection of the image light L1 is sufficiently obtained.

Therefore, in a state in which the anti-reflection layer 121 is laminated on the vehicle interior side of the first glass plate 122, the incident angle γ1 at which the reflection Y value of the light incident from the vehicle interior side (+Z side) is minimized and the angle of incidence to the window glass 12 are The incident angle θ1 of the image light L1 satisfies the relationship θ1−30≦γ1≦θ1+30°, thereby reducing double images caused by reflection of part of the image light incident on the window glass 12. can be done.
This also increases the amount of image light L1 incident on the window glass 12 and increases the amount of image light L2 reflected by the cholesteric liquid crystal layer 124, so that the window glass 12 and the image display device 10 are brighter and more visible. It can display high quality images.

Image light L<b>1 that has entered the window glass 12 and passed through the antireflection layer 121 , the first glass plate 122 , and the first intermediate layer 123 enters the cholesteric liquid crystal layer 124 . As described above, most of the image light L1 is reflected by the cholesteric liquid crystal layer 124 and emitted toward the observer E side. The image light L2 reflected by the cholesteric liquid crystal layer 124 allows the observer E to view the image.

A portion of the image light L3 that has passed through the cholesteric liquid crystal layer 124 passes through the quarter-wave retardation layer 125 and becomes linearly polarized light. Then, the linearly polarized image light L3 is transmitted through the second intermediate layer 126 and the second glass plate 127 and emitted out of the vehicle.
At this time, the linearly polarized image light L3 is incident as P-polarized light on the interface between the second glass plate 127 and the air (surface 127b of the second glass plate 127 on the vehicle exterior side).
When the P-polarized image light L3 is incident on the interface (surface 127b) between the second glass plate 127 and the air from the second glass plate 127 side, the image light L3 must be It is preferable that the light is incident on the surface 127b at the Brewster angle when it is incident from the second glass plate 127 side. At this time, if the emission angle of the image light L3 from the second glass plate 127 is θ2 (°), the emission angle θ2 is equal to the Brewster angle β (°) when the light is incident on the surface 127b from the air side. equal.

Therefore, the fact that the emission angle θ2 of the P-polarized image light L3 from the second glass plate 127 is equal to the Brewster angle β means that the image light L3 at the interface (surface 127b) between the second glass plate 127 and the air It is preferable from the viewpoint of maximizing the transmittance. Further, the inventors of the present application found that if the output angle θ2 is within the range of β±20°, that is, if β−20°≦θ2≦β+20° is satisfied, the interface between the second glass plate 127 and the air It was found that a sufficiently high transmittance (sufficiently low reflectance) of the image light L3 at (surface 127b) can be ensured.
Therefore, when the output angle θ2 and the Brewster angle β satisfy β−20°≦θ2≦β+20°, reflection of the image light L3 at the interface between the second glass plate 127 and the air is suppressed and its transmission is suppressed. This is preferable from the viewpoint of increasing the efficiency and reducing double images.

The window glass 12 includes a first glass plate 122 and a second glass plate 127 made of the same material. is equal to the emission angle of the image light L3. Also, the incident angle θ1 of the image light L1 on the window glass 12 is substantially equal to the incident angle on the first glass plate 122, and the output angle θ2 of the image light L3 from the window glass 12 is the angle from the second glass plate 127. It is the emission angle of the image light L3.
Therefore, it is preferable that the incident angle of the image light L1 and the Brewster's angle β satisfy the following relationship.
β-20°≤θ1≤β+20°
This effectively suppresses double images caused by part of the image light L3 transmitted through the cholesteric liquid crystal layer 124 being reflected toward the viewer E at the interface between the window glass 12 and the air outside the vehicle.

Next, external light G such as sunlight is a mixture of lights oscillating in all directions. Therefore, of the external light G1 incident on the window glass 12 from the outside of the vehicle, part of the external light G2 is reflected by the cholesteric liquid crystal layer 124 toward the outside of the vehicle, and part of the external light G3 is transmitted through the cholesteric liquid crystal layer 124. It reaches observer E in the car. That is, the amount of external light reaching the observer E is reduced due to reflection on the cholesteric liquid crystal layer 124 and the like. may decrease.

However, since the window glass 12 of the present embodiment includes the antireflection layer 121, the window glass 12 (first glass plate 122 ) can be suppressed, and the observer E can brightly observe the outside of the vehicle through the window glass 12 .

As described above, according to the present embodiment, reflection of image light at both the vehicle-interior and vehicle-exterior interfaces between the window glass 12 and the air is suppressed, and a double image caused by such reflected light is effectively eliminated. can be effectively reduced, and a good image with high visibility can be displayed.
Further, according to the present embodiment, it is possible to increase the amount of image light incident on the window glass 12 and display a bright image.
Further, according to the present embodiment, the transmittance of the window glass 12 for outside light can be maintained, and the visibility of the scenery outside the vehicle when the observer E observes the outside of the vehicle through the window glass 12 can be improved.

(Second embodiment)
FIG. 4 is a diagram for explaining the layer structure and the like of the window glass 22 (reflective display panel) of the second embodiment.
The window glass 22 of the second embodiment does not include the quarter-wave retardation layer 125 and includes the second antireflection layer 228 on the outside of the vehicle of the second glass plate 127, unlike the window glass of the first embodiment described above. 12, it has the same form as the window glass 12 of the first embodiment. Therefore, portions that perform the same functions as those of the first embodiment described above are denoted by the same reference numerals or the same reference numerals at the end thereof, and overlapping descriptions are omitted as appropriate.
The window glass 22 of the second embodiment includes an antireflection layer (first antireflection layer) 121, a first glass plate 122, a first intermediate layer 123, a cholesteric liquid crystal layer 124, a second intermediate layer 126, and a second glass plate 127. , a second antireflection layer 228 .
This window glass 22 can be applied to the image display device 10 shown in the above-described first embodiment. Also, the image display device 10 having the window glass 22 of the second embodiment can be applied to the automobile 30 shown in the above-described first embodiment.

The antireflection layer (first antireflection layer) 121, the first glass plate 122, the first intermediate layer 123, the cholesteric liquid crystal layer 124, and the second glass plate 127 are as described in the first embodiment.
In this embodiment, the second intermediate layer 126 is provided between the second glass plate 127 and the cholesteric liquid crystal layer 124 to bond the second glass plate 127 and the cholesteric liquid crystal layer 124 together. The thickness and material of this second intermediate layer 126 are the same as those of the above-described first embodiment.

The second anti-reflection layer 228 is a layer provided on the vehicle outer side (−Z side) of the second glass plate 127, and similar to the anti-reflection layer 121, the second anti-reflection layer 228 serves as a window when light enters or exits the window glass 22. It has a function of suppressing reflection at the interface between the glass 22 and the air outside the vehicle.
In this embodiment, the second antireflection layer 228 has the same form as the antireflection layer 121 described above, but may have a different form. Moreover, the second antireflection layer 228 forms the surface of the window glass 12 on the outside of the vehicle, and desirably has weather resistance and durability.

FIG. 5 is a diagram showing an example of a method of manufacturing the window glass 22 (reflective display panel) of the second embodiment.
First, as shown in FIG. 5(a), a polymerizable liquid crystal material containing a chiral agent is coated on a PET base material 101, cured by irradiation with ultraviolet rays, and reflected at a wavelength of 550 nm by 45° specular reflection. A cholesteric liquid crystal layer 124 having a peak (center wavelength) was formed. In the present embodiment, the cholesteric liquid crystal layer 124 has a brightness peak (central wavelength) of reflected light at a wavelength of 550 nm with regular reflection at 45°. may be appropriately set according to the use environment of the video display device 10 or the like.
Next, as shown in FIG. 5(b), a second intermediate layer 126 as an adhesive is formed on the surface of the cholesteric liquid crystal layer 124, transferred to a second glass plate 127, and the PET substrate 101 is peeled off.
Next, as shown in FIG. 5C, an adhesive is applied to the surface of the obtained laminate on the cholesteric liquid crystal layer 124 side to form a first intermediate layer 123. , the laminate and the first glass plate 122 are adhered.

Next, as shown in FIG. 5D, a reflection suppressing layer 121 is formed on the surface of the obtained laminate on the side of the first glass plate 122, and a second reflection suppressing layer 121 is formed on the surface on the side of the second glass plate 127. By forming the suppression layer 228, the window glass 22, which is a reflective display panel, is formed.
In addition to the above example, the cholesteric liquid crystal layer 124 is formed on the PET substrate 101, transferred to the first glass plate 122 via the first intermediate layer 123, and then the second intermediate layer 126 is formed to form the second liquid crystal layer 124. A step of bonding to the glass plate 127 may be performed.

With reference to FIG. 4 described above, how image light and external light travel through the window glass 22 of the second embodiment will be described.
4 shows how the image light L (L1 to L3) and the external light G (G1 to G3) travel through the window glass 22. Although the refraction of light between layers is omitted, it is assumed that light is actually refracted appropriately between layers.

As described above, the image source 11 projects circularly polarized light onto the window glass 22 as the image light L1. The angle of incidence of the image light L1 on the window glass 22 is assumed to be θ1. And when the incident angle at which the reflection Y value of the reflected light on the first glass plate 122 is minimized is γ1, this embodiment also satisfies θ1−30°≦γ1≦θ1+30°. This makes it possible to more effectively suppress double images caused by reflection of part of the image light L<b>1 when incident on the window glass 22 .
Further, as a result, the amount of incident light of the image light L1 on the window glass 12 increases, and the amount of light reflected by the cholesteric liquid crystal layer 124 increases, so that the image display device 10 and the window glass 22 display a brighter image. can be done.

Next, the image light L 1 that has entered the window glass 22 and passed through the antireflection layer 121 , the first glass plate 122 , and the first intermediate layer 123 enters the cholesteric liquid crystal layer 124 . As described above, most of the image light L1 is reflected by the cholesteric liquid crystal layer 124 and emitted toward the observer E side. The image light L2 reflected by the cholesteric liquid crystal layer 124 allows the observer E to view the image.

Further, the image light L3 that has passed through the cholesteric liquid crystal layer 124 passes through the second intermediate layer 126 and the second glass plate 127 and is emitted outside the vehicle.
At this time, the reflection of the image light L3 at the interface between the window glass 22 and the air is suppressed because the second antireflection layer 228 is formed on the surface of the second glass plate 127 on the vehicle exterior side (−Z side). be. This effectively suppresses double images caused by part of the image light L3 transmitted through the cholesteric liquid crystal layer 124 being reflected toward the viewer E at the interface between the second glass plate 127 and the air.

In the window glass 22 of the present embodiment, the second antireflection layer 228 is laminated on the vehicle exterior side (−Z side) of the second glass plate 127, and the second antireflection layer 228 and the When the incident angle at which the reflection Y value of the reflected light on the second glass plate 127 is minimized is γ2 (°) and the incident angle of the image light L1 onto the window glass 22 is θ1, it is preferable to satisfy the following relationship. .
θ1-30≤γ2≤θ1+30°
This is for the following reasons.

In order to reduce the double image caused by the reflection of the image light L3 transmitted through the cholesteric liquid crystal layer 124 at the interface between the window glass 22 and the air outside the vehicle (−Z side), the window glass 22 and the vehicle It is preferable that the image light L3 has a low reflectance (high transmittance) at the interface with the outside air. Assuming that the emission angle of the image light L3 from the window glass 22 to the outside of the vehicle is θ2, the amount of light incident on the interface between the window glass 22 and the air outside the vehicle from the air side (outside the vehicle) at an incident angle θ2. Low reflectance is equivalent to being desirable.

In this embodiment, the first glass plate 122 and the second glass plate 127 are made of the same material, and the angle of incidence θ1 of the image light L1 on the window glass 22 is the same as that of the image light L3 emitted from the window glass 22. equal to the angle θ2.
Therefore, in a state where the second antireflection layer 228 is laminated on the vehicle outer side of the second glass plate 127, the light incident on the window glass 22 from the vehicle outer side (−Z side) passes through the second antireflection layer 228 and the second glass. When the incident angle γ2 at which the reflection Y value of the reflected light on the plate 127 is minimized is equal to the emission angle θ2 of the image light L3 from the window glass 22 (that is, the incident angle θ1 of the image light L1 to the window glass 22), Reflection of the image light L3 at the interface between the window glass 22 and the air outside the vehicle is most suppressed. Further, the inventors of the present application found that if the angle γ2 is within the range of θ2±30°, that is, within the range of θ1±30°, the image light L3 at the interface between the window glass 22 and the air outside the vehicle is It was discovered that the effect of sufficiently suppressing reflection can be obtained.
As described above, by satisfying θ1−30≦γ2≦θ1+30° between the angles γ2 and θ1, the double image reduction effect on the window glass 22 can be further enhanced.
In this embodiment, the second antireflection layer 228 is the same as the antireflection layer 121, so γ2=γ1, but the angle γ2 and the angle γ1 may have different values.

Next, external light G1 incident on the window glass 22 from the outside of the vehicle (−Z side) is partially reflected by the cholesteric liquid crystal layer 124 and directed outside the vehicle. It passes through the layer 124 and reaches an observer E inside the vehicle.

The window glass 22 includes the second antireflection layer 228 on the vehicle outer side (−Z side) of the second glass plate 127, and the antireflection layer 121 on the vehicle inner side (+Z side) of the first glass plate 122. , the transmittance of the window glass 22 for outside light can be improved, and when the observer E views the scenery outside the vehicle through the window glass 22, the outside of the vehicle is observed brightly, and the visibility can be improved.
In addition, since the window glass 22 includes the second antireflection layer 228 on the outside of the second glass plate 127, part of the external light G2 reflected by the cholesteric liquid crystal layer 124 is reflected between the second glass plate 127 and the air. It is also possible to prevent the light from being reflected at the interface between the light and the light and directed toward the observer E, thereby hindering the visual recognition of the image and the scenery outside the vehicle.

As described above, according to the present embodiment, reflection of image light at both the vehicle-interior and vehicle-exterior interfaces between the window glass 22 and the air is suppressed, and a double image caused by such reflected light is effectively eliminated. can be effectively reduced, and a good image with high visibility can be displayed.
Further, according to the present embodiment, it is possible to increase the amount of image light incident on the window glass 22 and display a bright image.
Further, according to the present embodiment, the transmittance of outside light can be maintained, and the visibility when the observer E observes the outside of the vehicle through the window glass 22 can be improved.
Further, according to the present embodiment, the second antireflection layer 228 is provided on the outside of the vehicle of the second glass plate 127, so that the effect of improving the visibility when the observer E observes the scenery outside the vehicle is enhanced. be able to.
In addition, according to this embodiment, the number of layers between the first glass plate 122 and the second glass plate 127 can be reduced, so that handling during manufacturing can be improved, and manufacturing can be made easier.

Examples of the window glasses 12 and 22 (reflective display panels) of the first and second embodiments will be described below. The examples exemplified below are examples and are not intended to be limiting.
Examples 1 to 4 are examples of the window glass 12 of the first embodiment, and examples 5 and 6 are examples of the window glass 22 of the second embodiment. In the window glasses 12 of Examples 1 to 4, each layer from the first glass plate 122 to the second glass plate 127 is the same, and the shape of the antireflection layer 121 is different. In the window glasses 22 of Examples 5 and 6, each layer from the first glass plate 122 to the second glass plate 127 is the same as in Examples 1 to 4, and the antireflection layer 121 and the second antireflection layer 228 are the same as those of the antireflection layers 121 and 228. Each form is different. In addition, in each embodiment, the cholesteric liquid crystal layer 124 has a peak luminance (central wavelength) of reflected light at a wavelength of 550 nm at 45° specular reflection.

<Example 1>
The window glass 12 (reflective display panel) of Example 1 was formed by applying the following low refractive index layer composition 1 to the surface of the first glass plate 122 and thermally curing to form a low refractive index layer. , an antireflection layer 121 is formed. The antireflection layer 121 of Example 1 has a refractive index of 1.34 and a layer thickness of 150 nm.
In Example 1, the reflection Y value of the light reflected from the reflection suppression layer 121 and the first glass plate 122 of the light incident from the inside of the vehicle is the minimum at 45° specular reflection (that is, the incident angle γ1 = 45°).
(Composition 1 for low refractive index layer)
Hollow silica (particle diameter 60 nm) 1.2 parts TEOS (tetraethoxysilane) hydrolyzate 1 part IPA 97.8 parts

<Example 2>
In the window glass 12 of Example 2, the following high refractive index layer composition 2 is applied to the surface of the first glass plate 122 and thermally cured to form a high refractive index layer, and the following composition is further formed thereon. The antireflection layer 121 is formed by applying the low refractive index layer composition 3 and thermally curing it to form a low refractive index layer. In Example 2, the high refractive index layer has a refractive index of 1.50 and a layer thickness of 260 nm, and the low refractive index layer has a refractive index of 1.32 and a layer thickness of 150 nm.
In Example 2, the reflection Y value of the light reflected from the antireflection layer 121 and the first glass plate 122 of the light incident from the inside of the vehicle is the smallest (γ1=45°) at 45° specular reflection.
(Composition 2 for high refractive index layer)
Zirconium oxide particles 0.2 parts TEOS (tetraethoxysilane) hydrolyzate 1 part IPA 98.8 parts (low refractive index layer composition 3)
Hollow silica (particle diameter 60 nm) 1.5 parts TEOS (tetraethoxysilane) hydrolyzate 1 part IPA 97.5 parts

<Example 3>
In the window glass 12 of Example 3, the antireflection layer 121 is formed by alternately forming a low refractive index layer made of silica and a high refractive index layer made of niobium oxide on the surface of the first glass plate 122 in total five layers. ing. In Example 3, the refractive index of the high refractive index layer is 2.3 and the refractive index of the low refractive index layer is 1.47. In addition, the thickness of each layer is, in order from the first glass plate 122 side, a low refractive index layer (silica) 10 nm, a high refractive index layer (niobium oxide) 60 nm, a low refractive index layer (silica) 30 nm, a high refractive index layer ( Niobium oxide) is 70 nm, the low refractive index layer (silica) is 160 nm, and the total thickness of the antireflection layer 121 is 330 nm. The low refractive index layer and high refractive index layer are formed by sputtering.
In Example 3, the reflection Y value of the light reflected from the antireflection layer 121 and the first glass plate 122 of the light incident from the inside of the vehicle is the smallest (γ1=45°) at 45° specular reflection.

<Example 4>
The window glass 12 of Example 4 has a reflection suppression layer 121 similar to that of the window glass 12 of Example 3, and the reflection suppression layer 121 is further coated with OPTOOL DSX (manufactured by Daikin Industries, Ltd.). An antifouling layer having a layer thickness of 5 nm was formed.

<Example 5>
In the window glass 22 of Example 5, the antireflection layer 121 is formed on the vehicle inner side of the first glass plate 122 and the second antireflection layer 228 is formed on the second glass plate 127 on the vehicle outer side.
In Example 5, the antireflection layer 121 is formed by alternately forming five layers of a low refractive index layer of silica and a high refractive index layer of niobium oxide on the surface of the first glass plate 122. Similarly, The second anti-reflection layer 228 is also formed on the surface of the second glass plate 127 by alternately forming a low refractive index layer of silica and a high refractive index layer of niobium oxide in total five layers. That is, the antireflection layer 121 and the second antireflection layer 228 have the same form.
In Example 5, the refractive index of the high refractive index layer is 2.3 and the refractive index of the low refractive index layer is 1.47. The thickness of each layer is, in order from the side of the first glass plate 122 and the second glass plate 127, a low refractive index layer (silica) of 10 nm, a high refractive index layer (niobium oxide) of 60 nm, and a low refractive index layer (silica) of 30 nm. , the high refractive index layer (niobium oxide) is 70 nm, the low refractive index layer (silica) is 160 nm, and the total thickness of the antireflection layer 121 and the second antireflection layer 228 is 330 nm. The low refractive index layer and high refractive index layer are formed by sputtering.
In Example 5, the reflection Y value of the light reflected from the antireflection layer 121 and the first glass plate 122 of the light incident from the inside of the vehicle is the smallest (γ1=45°) at 45° specular reflection. Further, in Example 5, the reflection Y value of the light reflected from the second antireflection layer 228 and the second glass plate 127 of the light incident from the outside of the vehicle is the smallest (γ2=45°) at 45° specular reflection.

<Example 6>
The window glass 22 of Example 6 includes the antireflection layer 121 and the second antireflection layer 228 similar to those of Example 5. Optool DSX (manufactured by Daikin) is applied thereon to form an antireflection layer having a thickness of 5 nm. A dirty layer is formed respectively.

<Comparative Example 1>
In the window glass of Comparative Example 1, the antireflection layer 121 is formed by applying the composition 1 for the low refractive index layer to the surface of the first glass plate 122 to form a low refractive index layer. . The antireflection layer 121 (low refractive index layer) of Comparative Example 1 has a refractive index of 1.34 and a layer thickness of 100 nm.
In Comparative Example 1, the reflection Y value of the light reflected from the antireflection layer 121 and the first glass plate 122 of the light incident from the inside of the vehicle is the minimum (γ1=5°) at regular reflection of 5°.

<Comparative Example 2>
In the window glass of Comparative Example 2, the above high refractive index layer composition 2 was applied to the surface of the first glass plate 122 and thermally cured to form a high refractive index layer, and the above low refractive index layer was formed thereon. The antireflection layer 121 is formed by applying the index layer composition 3 and thermally curing it to form a low refractive index layer. In Comparative Example 2, the high refractive index layer has a refractive index of 1.57 and a layer thickness of 160 nm, and the low refractive index layer has a refractive index of 1.32 and a layer thickness of 100 nm.
In Comparative Example 2, the reflection Y value of the light reflected from the antireflection layer 121 and the first glass plate 122 of the light incident from the inside of the vehicle is the smallest (γ1=5°) at regular reflection of 5°.

<Comparative Example 3>
In the window glass of Comparative Example 3, the antireflection layer 121 is formed by alternately forming five layers of a low refractive index layer of silica and a high refractive index layer of niobium oxide on the surface of the first glass plate 122 . . In Comparative Example 3, the refractive index of the high refractive index layer is 2.3 and the refractive index of the low refractive index layer is 1.47.
In addition, the thickness of each layer is, in order from the first glass plate 122 side, a low refractive index layer (silica) 5 nm, a high refractive index layer (niobium oxide) 40 nm, a low refractive index layer (silica) 20 nm, a high refractive index layer ( Niobium oxide) is 50 nm, the low refractive index layer (silica) is 110 nm, and the total thickness of the antireflection layer 121 is 225 nm. The low refractive index layer and the high refractive index layer are formed by sputtering.
In Comparative Example 3, the reflection Y value of the light reflected from the antireflection layer 121 and the first glass plate 122 of the light incident from the inside of the vehicle is the smallest (γ1=5°) at regular reflection of 5°.

<Comparative Example 4>
In the window glass 12 of Comparative Example 4, each layer from the first glass plate 122 to the second glass plate 127 is the same as in Examples 1 to 4, but the antireflection layer 121 is provided on the vehicle inner side of the first glass plate 122. It differs in that it is not laminated.

<Comparative Example 5>
The window glass 22 of Comparative Example 5 has the same layers as those of Examples 5 and 6 from the first glass plate 122 to the second glass plate 127, but the antireflection layer 121 is provided on the vehicle inner side of the first glass plate 122. The second glass plate 127 is not laminated, and the second antireflection layer 228 is not laminated on the vehicle outer side of the second glass plate 127 .

These Examples 1 to 4 The image display devices 10 of Examples 1 to 4 having the window glass 12, The image display devices 10 of Examples 5 and 6 having the window glass 22 of Examples 5 and 6, and Comparative Examples 1 to 5 Each of the image display devices of Comparative Examples 1 to 5 having the window glass of No. 1 was actually placed in an automobile 30, and the visibility of the image, the reflection of external light, and the like were visually observed and evaluated. The image display devices 10 of each example and each comparative example were placed in a bright environment in which outside light such as sunlight entered the window glasses 12 and 22, and displayed the same image. Further, the image source 11 is arranged so that the image light L is incident on the center of the area A of the window glass 12, 22 where the image is to be displayed at an incident angle θ1=45°.
In the window glasses 12 of Examples 1 to 4, the angle γ1 at which the reflection Y value of the reflected light from the antireflection layer 121 and the first glass plate 122 is minimized satisfies θ1−30°≦γ1≦θ1+30°. Also for the window glasses 22 of Examples 5 and 6, the incident angle γ1 at which the reflection Y value of the reflected light on the antireflection layer 121 and the first glass plate 122 is minimized, The incident angle γ2 at which the reflection Y value of the reflected light is minimized satisfies θ1−30°≦γ1≦θ1+30° and θ1−30°≦γ2≦θ1+30°. The window glasses of Comparative Examples 1 to 3 do not satisfy θ1−30°≦γ1≦θ1+30°. The window glass of Comparative Example 4 does not include the antireflection layer 121 , and the window glass of Comparative Example 5 does not include the antireflection layer 121 and the second antireflection layer 228 .
Further, in the window glass 12 of Examples 1 to 4, the Brewster angle β when incident from the air side at the interface between the second glass plate 127 and the air is 56°, and the incident angle θ1 on the window glass 12 is 56°. 45°, which satisfies β−20°≦θ1≦β+20°.

In the image display devices 10 of Examples 1 to 6, double images were reduced, and good images with high visibility were observed. In addition, in the image display devices 10 of Examples 1 to 6, the reflection of outside light is also suppressed, and the visibility of the scenery outside the vehicle when the outside of the vehicle is observed through the window glasses 12 and 22 is also improved.
Further, comparing the video display devices 10 of Examples 3 and 5, the video display device 10 of Example 5 corresponding to the example of the second embodiment is the example corresponding to the example of the first embodiment. As compared with the display device 10 of No. 3, the outside of the vehicle was observed brightly, and the visibility of the scenery outside the vehicle was high.
Furthermore, in the image display devices 10 of Examples 4 and 6, the antifouling layer prevents dirt from adhering to the window glasses 12 and 22, thereby improving the visibility of the image. Further, in Example 6, adhesion of dirt to the outside of the vehicle on the window glass 22 was reduced, and the visibility of the scenery outside the vehicle was high.
On the other hand, in the video display devices of Comparative Examples 1 to 5, a double image occurs, making it difficult to visually recognize the video. , the visibility of the scenery outside the vehicle was degraded. In particular, in the image display devices of Comparative Examples 4 and 5, the double image occurred significantly more than the other comparative examples.

(deformed form)
Various modifications and changes are possible without being limited to the embodiments described above, and they are also within the scope of the present invention.
(1) In each embodiment, when the image light L is projected from the image source 11 onto the window glasses 12 and 22 (reflective display panels), depending on the positional relationship between the image source 11 and the window glasses 12 and 22, The image light projected from the image source 11 may be reflected by a reflecting mirror (not shown) and projected onto the window glasses 12 and 22 .

(2) In each embodiment, the reflective display plate is applied to the window glass 12, 22 of the front window of the automobile 30. However, the present invention is not limited to this. It may be a panel-shaped member separate from the window glasses 12, 22 (front windows) arranged on a board or the like. When such a panel-like member is used as a reflective display plate, a glass plate may be used as the first transparent substrate and the second transparent substrate, or a plate-shaped plate made of highly transparent resin such as acrylic resin may be used. You may use a member.
Also, in each embodiment, the reflective display panel may be applied to the side window, rear window, sunroof, etc. of the automobile 30 .

(3) In each embodiment, the image source 11 is arranged in the dashboard, and the image light is projected from below the window glasses 12 and 22 (reflective display panels) in the vertical direction. It is not limited to this, and may be arranged on the ceiling or the like inside the car 30 and project the image light from above in the vertical direction to the window glasses 12 and 22 . In addition, the image display device 10 may display an image not only on the area of the window glasses 12 and 22 in front of the driver's seat, but also in the area in front of the passenger's seat.

(4) In each embodiment, the image display device 10 is arranged in an automobile 30, and the window glasses 12 and 22, which are reflective display plates, are used for the front windows. The image display device 10 may be arranged on a ship, railroad car, aircraft, etc., and the reflective display plate may be applied to the window.
Also, the reflective display panel may be applied to, for example, windows of buildings such as stores. When the reflective display board is applied to the show window of a store, it is possible to show the products displayed in the show window to customers from the outside of the store, and to display product information and the like on the show window.

(5) In each embodiment, the cholesteric liquid crystal layer 124 and the quarter-wave retardation layer 125 are formed on the entire surface of the window glasses 12 and 22, but are not limited thereto. In other parts, the thicknesses of the first intermediate layer 123 and the second intermediate layer 126 are increased by the thicknesses of the cholesteric liquid crystal layer 124 and the quarter-wave retardation layer 125. It may be in the form of

(6) In each embodiment, the cholesteric liquid crystal layer 124 does not have an alignment film, but may have an alignment film if necessary.

(7) In each embodiment, the image source 11 may be configured such that the projection angle of the image light L is automatically adjusted according to the size of the image to be displayed, the position at which the image is displayed, and the like. . In addition, a plurality of image sources 11 may be arranged inside the automobile 30 . In this case, the image display device 10 may be provided with a control section as shown in the figure, and switch between the plurality of image sources 11 in accordance with the size and position of the image to be displayed according to instructions from the control section.

In addition, although each embodiment and modification can also be combined and used suitably, detailed description is abbreviate|omitted. Moreover, the present invention is not limited by the embodiments and the like described above.

10 image display device 11 image source 12, 22 window glass (reflective display panel)
121 antireflection layer 122 first glass plate 123 first intermediate layer 124 cholesteric liquid crystal layer 125 1/4 wavelength retardation layer 126 second intermediate layer 127 second glass plate 228 second antireflection layer 30 automobile

Claims (4)

a reflective display panel that is translucent and reflects at least part of projected image light to display an image;
an image source that projects image light containing at least circularly polarized light onto the reflective display panel;
A video display device comprising
The reflective display panel is
a first transparent substrate having translucency and provided on the incident side of the image light in the thickness direction of the reflective display panel;
a second transparent substrate having translucency, made of the same material as that of the first transparent substrate, and arranged on the back side of the first transparent substrate in the thickness direction of the reflective display panel;
a cholesteric liquid crystal layer that is provided between the first transparent substrate and the second transparent substrate and reflects circularly polarized light in a predetermined wavelength region and in one rotational direction;
a reflection suppressing layer laminated on the incident side surface of the first transparent substrate;
a second antireflection layer laminated on the back side surface of the second transparent substrate;
with
The incident angle of the image light to the reflective display panel is θ1, and the light incident on the reflective display panel from the back side has a minimum reflection Y value of the reflected light on the second antireflection layer and the second transparent substrate. When the incident angle of is γ2,
θ1−30°≦γ2≦θ1+30°, and
0°≤γ2<90°, 0°≤θ1<90°
to satisfy
An image display device characterized by: The image display device according to claim 1,
The incident angle γ2 is 45°,
An image display device characterized by: In the image display device according to claim 1 or claim 2,
Let θ1 be the angle of incidence of the image light on the reflective display panel,
Let γ1 be the incident angle of the light at which the reflection Y value of the light reflected by the antireflection layer and the first transparent substrate of the light incident on the reflective display panel from the incident side is minimized,
θ1-30°≤γ1≤θ1+30°
to satisfy
An image display device characterized by: A vehicle equipped with the image display device according to any one of claims 1 to 3 ,
The image source is located inside the vehicle,
The reflective display panel is a translucent part of the vehicle;
A vehicle characterized by

Images