JP2018025722A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device in which visibility is ensured while sufficiently reducing influences of external light incident at a predetermined angle to a component in the display device (for example, a reflection member) through a windshield or the like (for example, a windshield), hot spots (bright spots) are prevented, image blur is prevented and the contrast is improved.SOLUTION: The display device includes: a light irradiation part for radiating display light; a reflection member for reflecting the display light radiated from the light irradiation part toward a light-transmitting member; and an anisotropic optical film having at least an anisotropic light diffusion layer that shows changes in a linear transmittance depending on an angle of incident light of the display light or external light and that has a matrix region and a plurality of columnar structures. The anisotropic optical film is disposed on a reflective surface side of the reflection member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a display device that can be mounted on a moving body or the like and that allows a virtual image of the display image to be visually recognized by irradiating a windshield or the like such as the moving body with the display image.

  2. Description of the Related Art Conventionally, various means have been used as information providing means for providing driving information such as route guidance and obstacle warning to a passenger of a moving body such as a vehicle. For example, display on a liquid crystal display installed on a moving body, sound output from a speaker, and the like. In recent years, a head-up display (HUD) device is mounted on a vehicle or the like as one of such information providing means.

  In the head-up display device, a device main body is generally arranged inside an instrument panel of a vehicle. The display light representing the display image displayed on the display unit inside the apparatus main body is called a vehicle windshield (front glass) or combiner via an optical path including a reflecting member such as a magnifying mirror. Irradiation (projection, projection) is performed toward an irradiation area such as an optical member (half mirror), and a virtual image is formed at a predetermined distance when viewed from the viewpoint position of the driver.

  As a result, when the driver looks forward in a normal driving posture, he / she visually recognizes a display image irradiated (projected) by the head-up display device together with a part of the vehicle body and the front scenery seen through the windshield. can do. The display image visually recognized by the driver is formed as a virtual image in front of the windshield surface, for example, at a distance of about several meters from the viewpoint, so the driver should adjust his eyes while driving. It is possible to simultaneously recognize the display image of the head-up display together with the scenery in front.

  For example, Patent Document 1 discloses a related art related to a head-up display device for a vehicle. Patent Document 1 discloses a technique in which a diffusion layer having a reflection directivity is stacked on a reflection mirror in order to provide a head-up display device with good visibility even under bright external light conditions.

JP 2010-256867 A

  A vehicle head-up display device generally irradiates a display image of display light so that a virtual image seen from the position of the driver's viewpoint forms an image in front of a vehicle windshield or the like (for example, front glass) ( Project). Accordingly, when a driver driving a vehicle looks forward through a windshield or the like (for example, a windshield), an object such as a landscape in front or a part of the vehicle body (for example, a hood) is overlapped. The display image of the head-up display device can be visually recognized as a virtual image.

  However, for example, in a situation where strong external light from the sun arrives, such as during the daytime in fine weather, the amount of external light is larger than the amount of virtual image displayed by the head-up display device. Under the influence of light, it becomes difficult to visually recognize the display of the virtual image. Therefore, for example, as disclosed in Patent Document 1, it may be effective to suppress the influence of external light by laminating a diffusion layer having reflection directivity on a reflection mirror.

  However, since the head-up display device performs display by irradiation (projection, projection) virtual images, for example, when the intensity of outside light is very high, such as daytime in fine weather, a windshield or the like (for example, windshield ), When outside light is incident on the head-up display device (for example, a reflection mirror) at a predetermined angle, even if a diffusion layer having reflection directivity is laminated on the reflection mirror, There is a problem that sufficient visibility cannot be secured because the influence of light is too great.

  The present invention has been made in view of the above-described circumstances, and its purpose is when the influence of external light is large, and it is placed in a display device (for example, a reflection mirror) through a windshield or the like (for example, a windshield). Display that improves visibility by sufficiently reducing the influence of external light incident at a predetermined angle, preventing hot spots (bright spots), preventing image blurring, and contrast To provide an apparatus.

In order to solve the above problems, the display device of the present invention provides:
A light irradiator that emits display light;
A reflective member that reflects the display light emitted from the light irradiator to the translucent member;
An anisotropic optical film comprising at least an anisotropic light diffusion layer having a matrix region and a plurality of columnar structures, wherein the anisotropic light diffusion layer has a linear transmittance changing according to an incident light angle of the display light or external light. When,
With
The anisotropic optical film is provided on the reflecting surface side of the reflecting member.

  According to the present invention, visibility can be ensured by sufficiently reducing the influence of external light incident at a predetermined angle into a display device (for example, a reflecting member) through a windshield or the like (for example, a windshield). it can.

It is a schematic block diagram which shows the installation state and optical path to the vehicle of the display apparatus seen from the side of the vehicle by this Embodiment (1st Embodiment). The schematic diagram which shows an example of the structure of the anisotropic optical film (anisotropic light diffusion layer) which has the columnar area | region of the pillar structure and louver structure by this Embodiment, and the mode of the transmitted light which injected into these anisotropic optical films It is. It is explanatory drawing which shows the evaluation method of the light diffusivity of the anisotropic optical film by this Embodiment. It is a graph which shows the relationship between the incident light angle and the linear transmittance | permeability to the anisotropic optical film (anisotropic light-diffusion layer) of the pillar structure and louver structure shown in FIG. 2 by this Embodiment. It is a graph for demonstrating the diffusion area | region and non-diffusion area | region by this Embodiment. It is a schematic diagram which shows the structural example of the anisotropic light-diffusion layer which has the pillar structure and louver structure in the anisotropic optical film by this Embodiment, (a) is a louver structure, (b) is a pillar structure. It is a three-dimensional polar coordinate display for demonstrating the scattering center axis | shaft in an anisotropic light-diffusion layer. The angle at which the display light irradiated from the light irradiation unit according to the present embodiment is incident or specularly reflected on the anisotropic optical film (anisotropic light diffusion layer) (arrangement relationship between the light irradiation unit and the anisotropic optical film) It is a figure explaining. In FIG. 1 by this Embodiment, it is a figure explaining a mode that external light is permeate | transmitted by the anisotropic light film (anisotropic light diffusion layer) provided in the reflection member. In this Embodiment (2nd Embodiment), it is a figure which shows the structure which laminated | stacked the diffusion member on the anisotropic optical film (anisotropic light diffusion layer). In this Embodiment (3rd Embodiment), it is a figure which shows the structure which laminated | stacked the polarizing member on the diffusion member. In this Embodiment (4th Embodiment), it is a schematic block diagram which shows the installation state to the vehicle of the display apparatus seen from the side of a vehicle, Comprising: An anisotropic optical film (anisotropic light-diffusion layer) on a windshield It is a figure which shows the structure in which () was provided. In this Embodiment (5th Embodiment), it is a schematic block diagram which shows the installation state to the vehicle of the display apparatus seen from the side of a vehicle, Comprising: It is a figure which shows the structure provided with the combiner.

  Embodiments will be described below with reference to the drawings.

(First embodiment)
<< Disposition of Display Device 3 and Description of Virtual Image 50 and Optical Path >>
First, a head-up display device 3 (hereinafter referred to as a HUD device) as a display device according to the present embodiment will be described. The HUD device 3 is used by being mounted on a general vehicle. FIG. 1 is a schematic configuration diagram showing an installation state and an optical path of the HUD device 3 on the vehicle as viewed from the side of the vehicle. In the following description, a direction along gravity in a vehicle in a stationary state is a downward direction, and a direction opposite to the downward direction is an upward direction.

  As shown in FIG. 1, the HUD device 3 includes a light irradiation unit 31, a reflection member 32, and an anisotropic light diffusion layer 100 as main components.

<Virtual image 50 and optical path L>
The HUD device 3 irradiates (projects and projects) the display light L representing the display image irradiated from the light irradiation unit 31 onto the projection area 41 of the windshield 40 via the reflection member 32 and the anisotropic light diffusion layer 100. . Then, the display image is formed on the vehicle front extension line of the line connecting the driver's eye point (viewpoint) EP and the projection area 41, and the display image is formed as a virtual image 50. As a result, the driver can visually recognize the scenery in front of the vehicle and the virtual image 50 through the windshield 40 from the driver's eye point (viewpoint) EP.

  Therefore, the driver hardly needs to move the viewpoint, and the focus adjustment of the eyes is unnecessary, so that very good visibility can be obtained. However, when the outside light such as sunlight in the morning, noon, and evening is strong, the light quantity of the virtual image 50 is smaller than the outside light, and thus the visibility may be extremely lowered.

<Windshield 40>
The windshield 40 (translucent member) is a windshield (front glass) on the front side of the vehicle. For example, a laminated glass formed of two sheets of glass and an intermediate film provided therebetween is used. . The windshield 40 has a slight curvature in the horizontal direction when viewed from above the vehicle and in the direction along the line of the windshield 40 when viewed from the side of the vehicle. The image can be enlarged and displayed further away. Since the windshield 40 has translucency that allows light incident from the front of the vehicle to pass therethrough, the driver can view the scenery in front of the vehicle and the virtual image 50 at the same time.

  In FIG. 1, an example in which the projection area 41 that irradiates (projects) the display light L is the windshield 40 and the driver visually recognizes the display light L reflected by the windshield 40 will be described. It is good also as a structure using the translucent member (for example, a combiner, an anisotropic optical film, etc.) which has translucency instead of.

<Display image>
The display image emitted from the light irradiation unit 31 can be, for example, map information in the vehicle navigation system, current position information of the vehicle on the map, or guidance information to the destination. Moreover, as a display image, it is good also as information, such as a vehicle speed, an engine speed, an engine cooling water temperature, and a battery voltage, as vehicle information at the time of vehicle travel.

<Example of arrangement of HUD device 3>
As shown in FIG. 1, the HUD device 3 is accommodated inside an instrument panel (not shown) in the downward direction of the windshield 40. The HUD device 3 includes a housing 30 and an opening 33 provided in a part of the housing 30, and the display light L representing a display image is displayed from the opening 33 toward the outside of the instrument panel. Can be irradiated. The instrument panel is provided with an opening window (not shown) having the same size as the opening 33, for example, in order to pass the display light L through the windshield 40. The opening 33 may be provided with a translucent cover (dust-proof cover) made of acrylic or the like, for example, in order to prevent dust and dust from entering the HUD device 3.

  The HUD device 3 includes a housing 30 provided in a downward direction of the windshield 40 of the vehicle. In the housing 30, a light irradiation unit 31, a reflecting member 32, an anisotropic light diffusion layer 100, Is provided.

<Light irradiation unit 31>
The light irradiation unit 31 is a member that irradiates display light L representing a display image. For example, a video projection device. The video projection device includes, for example, a projector (not shown) and a liquid crystal display with a backlight.

  The backlight uses, for example, an LED light source as a light source. The backlight irradiates light along the optical axis with respect to the liquid crystal display. The liquid crystal display has a function as a display that emits display light L representing a display image.

  The liquid crystal display irradiates the display image formed on the surface with the light emitted from the backlight as the display light L toward the reflecting member 32 on the opposite side of the backlight. The surface on which the display light L of the liquid crystal display is irradiated faces, for example, the vertical direction in FIG. 1 (perpendicular to the vehicle front-rear direction in FIG. 1), and the optical axis of the display light extends in the vehicle front-rear direction. It arrange | positions so that it may face (irradiation direction faces the front side of a vehicle).

  The light irradiation unit 31 is not only a liquid crystal display but also an LCoS method using a reflective liquid crystal panel, a DLP method that scans light emitted from an LED with a micromirror to generate a display image, or irradiation from a laser light source. A laser system that scans the generated light to generate a display image may be used.

<Reflection member 32>
The reflecting member 32 is a member that changes the optical path by reflecting the display light L representing the display image from the light irradiation unit 31 to the projection area 41 of the windshield 40 through the opening 33.

  The reflection member 32 is, for example, an ordinary mirror that simply reflects the display light L by depositing a metal (eg, aluminum) on a resin (eg, polycarbonate, glass, polyester, etc.) to form a reflection surface. is there.

  The reflecting member 32 may be an aspherical mirror (for example, a concave mirror) that reflects and expands the display light L. The reflecting member 32 is fixed at a predetermined position of the housing 30 and is detachable from the housing 30.

  The number and types of the reflecting members 32 are not limited to the above-described configuration, and the reflecting member 32 having an appropriately designed configuration is used. For example, not only one reflecting member 32 but also two reflecting mirrors for changing the optical path of the display light L from the light irradiation unit 31 and a concave mirror for expanding the display light L reflected by the reflecting mirror. It may be configured.

  Further, the reflecting member 32 may be composed of two aspherical mirrors (a first aspherical mirror and a second aspherical mirror). In this case, the first aspherical mirror reflects the display light L from the light irradiation unit 31 toward the second aspherical mirror, and the second aspherical mirror reflects the reflected light from the first aspherical mirror to the windshield 40. Reflect toward you. The first aspherical mirror and the second aspherical mirror have an optical path changing action and a display image enlarging action.

<Anisotropic optical film (anisotropic light diffusion layer) 100>
In the housing 30, an anisotropic optical film (in which the linear transmittance changes depending on the incident light angle with respect to display light or external light incident on the reflecting surface side of the reflecting member 32, that is, has an incident light angle dependency ( An anisotropic light diffusion layer) 100 is provided. The anisotropic optical film (anisotropic light diffusion layer) 100 will be described in detail below. In addition, the reflective member 32 and the anisotropic optical film (anisotropic light diffusion layer) 100 should just be laminated | stacked through the transparent adhesion layer (not shown), for example.

<<< Definition of main terms >>>
Here, with respect to the anisotropic optical film (anisotropic light diffusion layer) 100, main terms are defined.
An “anisotropic optical film” means that when the anisotropic light diffusion layer is a single layer (only one layer), when the anisotropic light diffusion layer is formed by laminating two or more layers, the anisotropic light diffusion layer is a single layer. When the other surface (for example, an adhesive layer) is provided on the surface, the anisotropic light diffusion layer is a single layer, and the other surface (for example, the adhesive layer) is provided on both surfaces. Is included. Therefore, for example, when the anisotropic light diffusion layer is a single layer, it means that the single anisotropic light diffusion layer is an anisotropic optical film. Also, for example, when the anisotropic light diffusion layer is a single layer and a transparent adhesive layer is provided on both surfaces, the structure including the single layer anisotropic light diffusion layer and the transparent adhesive layer provided on both surfaces is It means an anisotropic optical film.
The “anisotropic light diffusion layer” has anisotropy and directivity in which the diffusion, transmission, and diffusion distribution of light change depending on the incident angle of light that changes depending on the incident angle of light (details will be described later). Therefore, it is different from a directional diffusion film having no incident angle dependency, an isotropic diffusion film, and a diffusion film oriented in a specific direction.
The “low refractive index region” and the “high refractive index region” are regions formed by the difference in local refractive index of the material constituting the anisotropic optical film according to the present invention, compared to the other. It is a relative value indicating whether the refractive index is low or high. These regions are formed when the material forming the anisotropic optical film is cured.

  The “scattering center axis” is a direction in which the light diffusibility coincides with the incident light angle of light having a substantially symmetrical shape with respect to the incident light angle when the incident light angle to the anisotropic optical film is changed. means. “Substantially symmetrical” means that when the scattering center axis is inclined with respect to the normal direction of the film, the optical characteristics (“optical profile” described later) are not strictly symmetrical. Because. The scattering center axis should be confirmed by observing the inclination of the cross section of the anisotropic optical film with an optical microscope or by observing the projected shape of light through the anisotropic optical film while changing the incident light angle. Can do.

“Linear transmittance” generally relates to the linear transmittance of light incident on an anisotropic optical film, and the amount of transmitted light in the linear direction and the amount of incident light when entering from a certain incident light angle. It is a ratio with the light quantity, and is represented by the following formula.
Linear transmittance (%) = (Linear transmitted light amount / incident light amount) × 100

  In the present invention, both “scattering” and “diffusion” are used without distinction, and both indicate the same meaning. Furthermore, the meaning of “photopolymerization” and “photocuring” means that a photopolymerizable compound undergoes a polymerization reaction with light, and both are used synonymously.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Note that in the present specification and drawings, components having the same reference numerals have substantially the same structure or function.

<<< Structure and Properties of Anisotropic Optical Film >>>
As a premise for explaining the anisotropic optical film according to this embodiment with reference to FIGS. 2 to 5, a single-layer anisotropic optical film according to the prior art (an “anisotropic light diffusion layer” referred to in this embodiment is one layer) The structure and characteristics of the anisotropic optical film in the case of only the case will be described.

  FIG. 2 is a schematic diagram showing an example of the structure of a single-layer anisotropic optical film having columnar regions having a pillar structure and a louver structure, and the state of transmitted light incident on these anisotropic optical films. FIG. 3 is an explanatory diagram showing a method for evaluating the light diffusibility of an anisotropic optical film. FIG. 4 is a graph showing the relationship between the incident light angle and the linear transmittance on the anisotropic optical film having the pillar structure and the louver structure shown in FIG. FIG. 5 is a graph for explaining a diffusion region and a non-diffusion region.

<< Basic structure of anisotropic optical film >>
An anisotropic optical film is a film in which a region having a refractive index different from the matrix region of the film is formed in the film thickness direction. The shape of the regions having different refractive indexes is not particularly limited. For example, as shown in FIG. 2A, the matrix region 11 has a columnar shape (for example, a rod shape) with a minor axis and a minor axis having a small aspect ratio. ) Formed in the anisotropic optical film 10 (pillar structure anisotropic optical film) 10 in which the columnar regions 13 having different refractive indexes are formed, and in the matrix region 21 as shown in FIG. There is an anisotropic optical film (an anisotropic optical film having a louver structure) 20 in which columnar regions 23 having different refractive indexes formed in a columnar shape (for example, substantially plate shape) having a large aspect ratio are formed.

<< Characteristics of Anisotropic Optical Film >>
The anisotropic optical film having the above-described structure is a light diffusing film having different light diffusibility depending on an incident light angle to the film, that is, a light diffusing film having an incident light angle dependency. Light incident on the anisotropic optical film at a predetermined incident light angle is aligned in the orientation direction of regions having different refractive indexes (for example, the extending direction of the columnar region 13 in the pillar structure (orientation direction) or the columnar region 23 in the louver structure). Diffusion direction is given priority when it is substantially parallel to the height direction (thickness direction of the anisotropic optical film), and transmission is given priority when it is not parallel to this direction.

  Here, the light diffusibility of the anisotropic optical film will be described more specifically with reference to FIGS. Here, the light diffusibility of the anisotropic optical film 10 having the above-described pillar structure and the anisotropic optical film 20 having the louver structure will be described as an example.

  The light diffusibility evaluation method is performed as follows. First, as shown in FIG. 3, the anisotropic optical films 10 and 20 are disposed between the light source 1 and the detector 2. In this embodiment, the incident light angle 0 is set when the irradiation light I from the light source 1 is incident from the normal direction of the anisotropic optical films 10 and 20. The anisotropic optical films 10 and 20 are arranged so that they can be arbitrarily rotated around the straight line V, and the light source 1 and the detector 2 are fixed. That is, according to this method, the sample (anisotropic optical films 10 and 20) is arranged between the light source 1 and the detector 2, and the sample advances straight while changing the angle with the straight line L of the sample surface as the central axis. The linear transmittance that passes through and enters the detector 2 can be measured.

  The anisotropic optical films 10 and 20 were each evaluated for light diffusivity when the TD direction in FIG. 2 (axis in the width direction of the anisotropic optical film) was selected as the straight line L of the rotation center shown in FIG. The evaluation results of the obtained light diffusibility are shown in FIG. FIG. 4 shows the incident light angle dependency of the light diffusibility (light scattering property) of the anisotropic optical films 10 and 20 shown in FIG. 2 measured using the method shown in FIG. The vertical axis in FIG. 4 indicates the linear transmittance that is an index indicating the degree of scattering (in this embodiment, when a parallel light beam having a predetermined light amount is incident, the light amount of the parallel light beam emitted in the same direction as the incident direction is shown. Ratio, more specifically, linear transmittance = detected light amount of the detector 2 when the anisotropic optical films 10 and 20 are present (transmitted light amount in the linear direction of incident light) / anisotropic optical films 10 and 20 The amount of light detected by the detector 2 (the amount of incident light) when there is no light is shown, and the horizontal axis indicates the angle of light incident on the anisotropic optical films 10 and 20. The solid line in FIG. 4 indicates the light diffusibility of the anisotropic optical film 10 having a pillar structure, and the broken line indicates the light diffusibility of the anisotropic optical film 20 having a louver structure. In addition, the positive / negative of the incident light angle has shown that the direction which rotates the anisotropic optical films 10 and 20 is reverse.

  As shown in FIG. 4, the anisotropic optical films 10 and 20 have light diffusivity that depends on the incident light angle, and the linear transmittance changes depending on the incident light angle. Here, as shown in FIG. 4, the curve indicating the dependence of the light diffusivity on the incident light angle is hereinafter referred to as an “optical profile”. The optical profile does not directly express the light diffusivity, but if it is interpreted that the diffuse transmittance is increased (increased) due to the decrease of the linear transmittance, the light diffusivity is almost the same. It can be said that it shows. In other words, the diffuse transmittance of incident light increases as the linear transmittance decreases. In a normal isotropic light diffusion film, a peak-shaped optical profile having a peak near 0 ° is shown, but in the anisotropic optical films 10 and 20, the central axis (thickness) direction of the columnar regions 13 and 23, That is, the linear transmittance is once minimum at an incident light angle of −20 ° to + 20 ° as compared with the linear transmittance when incident in the scattering central axis direction (the incident light angle in this direction is 0 °). The linear transmittance increases as the incident light angle (absolute value thereof) increases, and the linear transmittance reaches the maximum value at an incident light angle of −60 ° to −30 ° or + 30 ° to + 60 °. A valley-shaped optical profile is shown. As described above, in the anisotropic optical films 10 and 20, the incident light is strongly diffused in the incident light angle range of −20 ° to + 20 ° close to the scattering central axis direction, but the absolute value of the incident light angle is more than that. In the larger incident light angle range, the diffusion is weakened and the linear transmittance is increased.

  Here, as shown in FIG. 4, the property (optical profile) in which diffusivity increases (increases) with respect to light (display light or external light) incident in a predetermined angle range and the linear transmittance has a minimum value. That is, in the predetermined angle range, the light has a property (optical profile) in which the diffusion of light is prioritized. Further, as shown in FIG. 4, light incident at an angle other than the predetermined angle range (display light) Alternatively, it has a property (optical profile) in which diffusivity is reduced and the linear transmittance is maximum with respect to outside light (optical profile). Such a property is called “anisotropic”. That is, it means that the diffusion and transmission of light change depending on the incident light angle of light. As described above, the predetermined angle range in which light diffusion is given priority is compared with the linear transmittance when the light is incident in the scattering central axis direction (the incident light angle in this direction is 0 °). For example, it refers to a range of incident light angles of −20 ° to + 20 °. Further, as described above, the linear transmittance in the case where the light is incident in the scattering central axis direction (the incident light angle in this direction is set to 0 °) is other than the predetermined angle range in which light transmission is prioritized. In comparison, for example, it refers to a range of incident light angles of −60 ° to −30 ° or + 30 ° to + 60 °.

  In addition, in the present invention, the light diffusion distribution differs depending on the diffusion angle but also changes depending on the incident light angle. The diffusion distribution further having light angle dependency is shown. That is, the diffusion, transmission, and diffusion distribution of light have anisotropy and directivity having incident light angle dependency that varies depending on the incident angle of light.

  Further, hereinafter, the angle range of two incident light angles with respect to the linear transmittance that is an intermediate value between the maximum linear transmittance and the minimum linear transmittance is referred to as a diffusion region (the width of the diffusion region is referred to as a “diffusion width”), and otherwise. The incident light angle range is referred to as a non-diffusion region (transmission region).

  Here, referring to FIG. 5, the diffusion region and the non-diffusion region will be described by taking the anisotropic optical film 20 having a louver structure as an example. FIG. 5 shows an optical profile of the anisotropic optical film 20 having the louver structure shown in FIG. 4. As shown in FIG. 5, the maximum linear transmittance (in the example of FIG. 78%) and the minimum linear transmittance (in the example of FIG. 5, the linear transmittance is about 6%). The incident light angle range between the light angles (inside the two incident light angles at the positions of the two black spots on the optical profile shown in FIG. 5) is the diffusion region, and the other (two on the optical profile shown in FIG. The incident light angle range outside the two incident light angles at the position of the black spot is a non-diffusing region.

  In the anisotropic optical film 10 having a pillar structure, as can be seen from the state of the transmitted light in FIG. 2A, the transmitted light has a substantially circular shape, and substantially the same light in the MD direction and the TD direction. It shows diffusivity. That is, in the anisotropic optical film 10 having a pillar structure, diffusion is isotropic when viewed in the azimuth direction. In addition, as shown by the solid line in FIG. 4, since the change in light diffusivity (particularly the optical profile near the boundary between the non-diffusing region and the diffusing region) is relatively gradual even when the incident light angle is changed, There is an effect of not causing a sense of incongruity due to a sudden change. However, the anisotropic optical film 10 has a low linear transmittance in the non-diffusing region, as can be understood by comparing with the optical profile of the anisotropic optical film 20 having the louver structure shown by the broken line in FIG. There is also a problem that display characteristics (luminance, contrast, etc.) are slightly degraded. Further, the anisotropic optical film 10 having a pillar structure also has a problem that the width of the diffusion region is narrower than that of the anisotropic optical film 20 having a louver structure. The pillar structure has no directivity of diffusion due to the azimuth, but has a directivity with respect to the distribution of diffusion.

  On the other hand, in the anisotropic optical film 20 having the louver structure, as can be seen from the state of the transmitted light in FIG. 2A, the transmitted light has a substantially needle shape, and is transmitted in the MD direction and the TD direction. Diffusivity varies greatly. That is, in the anisotropic optical film 20 having a louver structure, the diffusion has a directivity that greatly varies depending on the azimuth angle. Specifically, in the example shown in FIG. 2, diffusion is wider in the MD direction than in the case of the pillar structure, but diffusion is narrower in the TD direction than in the case of the pillar structure. Further, as shown by a broken line in FIG. 4, when the incident light angle is changed (in the case of this embodiment, in the TD direction), the light diffusibility (in particular, the optical profile near the boundary between the non-diffusing region and the diffusing region) changes. Therefore, when the anisotropic optical film 20 is applied to a display device, there is a possibility that a sudden change in luminance appears and an uncomfortable feeling is caused. In addition, the anisotropic optical film having a louver structure also has a problem that light interference (rainbow) is likely to occur. However, the anisotropic optical film 20 has an effect that the linear transmittance in the non-diffusion region is high and display characteristics can be improved. In particular, by matching the viewing angle of the preferred diffusion direction (MD direction in FIG. 2) with the direction in which the viewing angle is desired to be widened, it is possible to widen the viewing angle in the intended specific direction.

<<< Configuration of Anisotropic Optical Film According to this Embodiment >>>
The structure of the anisotropic optical film 100 according to this embodiment will be described with reference to FIG. FIG. 6 is a diagram showing an example of the configuration of the anisotropic light diffusion layers 110 and 120 in the anisotropic optical film 100 according to this embodiment. In the following, when the anisotropic optical film 100 is used, the anisotropic light diffusion layer having the anisotropic light diffusion layers 110 and 120 may be simply shown.

<< Overall structure >>
As shown in FIG. 6, the anisotropic optical film 100 is an anisotropic optical film having two anisotropic light diffusion layers 110 or 120 whose linear transmittance changes depending on the incident light angle.

  The anisotropic light diffusion layer 110 includes a matrix region 111 and a plurality of columnar structures 113 (columnar regions) having a refractive index different from that of the matrix region 111. The anisotropic light diffusion layer 120 includes a matrix region 121 and a plurality of columnar structures 123 (columnar regions) having different refractive indexes from the matrix region 121. Here, when it is simply expressed as a columnar region, the columnar region includes a pillar region and a louver region. In addition, when the term “columnar structure” is used, the columnar structure includes a pillar structure and a louver structure.

  Hereinafter, the anisotropic optical film 100 having the anisotropic light diffusion layer 110 or the anisotropic light diffusion layer 120 will be described in detail.

<< anisotropic light diffusion layer 110 >>
The anisotropic light diffusing layer 110 has the above-described louver structure (similar structure to the anisotropic optical film 20), and has a light diffusibility in which the linear transmittance changes depending on the incident light angle. The anisotropic light diffusion layer 110 is formed of a cured product of a composition containing a photopolymerizable compound. As shown in FIG. 6A, the matrix region 111 and a plurality of columnar structures having different refractive indexes from the matrix region 111 are used. 113 (columnar region). The orientation direction (extending direction) P of the columnar structure 113 is formed so as to be parallel to the scattering center axis, and is determined appropriately so that the anisotropic light diffusion layer 110 has desired linear transmittance and diffusibility. It has been. It should be noted that the fact that the scattering central axis and the alignment direction of the columnar region are parallel only needs to satisfy the law of refractive index (Snell's law), and does not need to be strictly parallel. Snell's law, when the light to the interface of the medium refractive index _{n 2} from a medium of refractive index _{n 1} is incident, between the incident light angle theta ₁ and refraction angle θ _2, n ₁ sinθ 1 = The relationship of n ₂ sin θ ₂ is established. For example, when n ₁ = 1 (air) and n ₂ = 1.51 (anisotropic optical film), when the incident light angle is 30 °, the alignment direction (refractive angle) of the columnar region is about 19 °. However, even if the incident light angle and the refraction angle are different from each other as long as Snell's law is satisfied, it is included in the parallel concept in this embodiment.

  In addition, as the anisotropic light-diffusion layer 110, the orientation direction of the columnar structure 113 may not match the film thickness direction (normal direction) of the film. In this case, in the anisotropic light diffusion layer 110, the incident light is strongly diffused in the incident light angle range (diffusion region) close to the direction inclined by a predetermined angle from the normal direction (that is, the orientation direction of the columnar structure 113). In the incident light angle range (non-diffusion region) beyond this, the diffusion is weakened and the linear transmittance is increased.

<Columnar structure 113>
The columnar structure 113 according to this embodiment is provided as a plurality of columnar hardened regions in the matrix region 111, and each columnar structure 113 is formed so that the alignment direction is parallel to the scattering center axis. It has been done. Accordingly, the plurality of columnar structures 113 in the same anisotropic light diffusion layer 110 are formed to be parallel to each other.

  The refractive index of the matrix region 111 may be different from the refractive index of the columnar structure 113, but how much the refractive index is different is not particularly limited and is a relative one. When the refractive index of the matrix region 111 is lower than the refractive index of the columnar structure 113, the matrix region 111 becomes a low refractive index region. Conversely, when the refractive index of the matrix region 111 is higher than the refractive index of the columnar structure 113, the matrix region 111 becomes a high refractive index region. Here, the refractive index at the interface between the matrix region 111 and the columnar structure 113 preferably changes gradually. By changing the angle gradually, the change in diffusibility when the incident light angle is changed becomes extremely steep, and the problem that glare is likely to occur is less likely to occur. By forming the matrix region 111 and the columnar structure 113 by phase separation accompanying light irradiation, the refractive index of the interface between the matrix region 111 and the columnar structure 113 can be gradually increased.

  The cross-sectional shape perpendicular to the alignment direction of the columnar structure 113 has a short diameter SA and a long diameter LA as shown in FIG. 6A. The short diameter SA and the long diameter LA can be confirmed by observing the anisotropic light diffusion layer 110 with an optical microscope (details will be described later). The cross-sectional shape of the columnar structure 113 is preferably one that satisfies a later-described aspect ratio range (2 or more), but is not particularly limited. For example, in FIG. 6A, the cross-sectional shape of the columnar structure 113 is shown as an elliptical shape, but the cross-sectional shape of the columnar structure 113 is not particularly limited.

<< anisotropic light diffusion layer 120 >>
The anisotropic light diffusing layer 120 has a pillar structure (similar structure to the anisotropic optical film 10), and has a light diffusibility in which the linear transmittance changes depending on the incident light angle. Further, as shown in FIG. 6B, the anisotropic light diffusion layer 120 is made of a cured product of a composition containing a photopolymerizable compound, and a matrix region 121 and a plurality of columnar structures having different refractive indexes from the matrix region 121. 123. The plurality of columnar structures 123 and the matrix regions 121 have an irregular distribution and shape, but optical characteristics (for example, linear transmittance) obtained by being formed over the entire surface of the anisotropic light diffusion layer 120 are substantially the same. It will be the same. Since the plurality of columnar structures 123 and the matrix region 121 have an irregular distribution or shape, the anisotropic light diffusion layer 120 according to this embodiment is less likely to cause light interference (rainbow).

<Columnar structure 123>
The columnar structure 123 according to this embodiment is provided as a plurality of columnar hardened regions in the matrix region 121, and each columnar structure 123 is formed so that the alignment direction is parallel to the scattering center axis. It has been done. Therefore, the plurality of columnar structures 123 in the same anisotropic light diffusion layer 120 are formed to be parallel to each other.

  Although the refractive index of the matrix area | region 121 should just differ from the refractive index of a columnar area | region, how much a refractive index differs is not specifically limited, It is a relative thing. When the refractive index of the matrix region 121 is lower than the refractive index of the columnar region, the matrix region 121 becomes a low refractive index region. Conversely, when the refractive index of the matrix region 121 is higher than the refractive index of the columnar region, the matrix region 121 becomes a high refractive index region.

  The cross-sectional shape perpendicular to the alignment direction of the columnar structure 123 has a short diameter SA and a long diameter LA as shown in FIG. 6B. The cross-sectional shape of the columnar structure 123 preferably satisfies an aspect ratio range (less than 2) described later. For example, in FIG. 6B, the cross-sectional shape of the columnar structure 123 is shown in a circular shape, but the cross-sectional shape of the columnar structure 123 is not limited to a circular shape, but an elliptical shape, a polygonal shape, an indefinite shape, There are no particular limitations on such a mixture.

<< Shape of columnar structure >>
<Aspect Ratio of Columnar Structure 113 and Columnar Structure 123>
The plurality of columnar structures 113 preferably have an aspect ratio (= average major axis / average minor axis) of an average value of the minor axis SA (average minor axis) and an average value of the major axis LA (average major axis) of 2 or more. It is more preferably 2 or more and less than 50, still more preferably 2 or more and 10 or less, and particularly preferably 2 or more and 5 or less.

  The plurality of columnar structures 123 preferably have an aspect ratio (= average major axis / average minor axis) of an average value (average minor axis) of the minor axis SA and an average value (average major axis) of the average major axis LA of less than 2. . Further, the aspect ratio between the average minor axis SA and the average major axis LA of the columnar region 123 is preferably less than 1.5, and more preferably less than 1.2.

  In the anisotropic optical film 100 according to this embodiment, the aspect ratio of the average minor axis and the average major axis of the plurality of columnar structures 113 and the plurality of columnar structures 123 are both within the above preferable range, so that at a higher level. It can be set as the anisotropic optical film which has various characteristics with sufficient balance.

<Average minor axis and average major axis of columnar structure 113 and columnar structure 123>
In addition, the average value of the minor axis SA (average minor axis) of the plurality of columnar structures 113 is preferably 0.5 μm or more, more preferably 1.0 μm or more, and 1.5 μm or more. Further preferred. On the other hand, the average value (average minor axis) of the minor axis SA of the plurality of columnar structures 113 is preferably 5.0 μm or less, more preferably 4.0 μm or less, and 3.0 μm or less. Further preferred. The lower limit value and the upper limit value of the average minor axis of the plurality of columnar structures 113 can be appropriately combined.

  Furthermore, the average value (average major axis) of the major axis LA of the plurality of columnar structures 113 is preferably 0.5 μm or more, more preferably 1.0 μm or more, and further preferably 1.5 μm or more. . On the other hand, the average value of the major axis LA (average major axis) of the plurality of columnar structures 113 is preferably 100 μm or less, more preferably 50 μm or less, and further preferably 30 μm or less. The lower limit value and the upper limit value of the average major axis of the plurality of columnar structures 113 can be appropriately combined.

  The average value (average minor axis) of the minor axis SA of the plurality of columnar structures 123 is preferably 0.5 μm or more, more preferably 1.0 μm or more, and 1.5 μm or more. Further preferred. On the other hand, the average value (average minor axis) of the minor axis SA of the plurality of columnar structures 123 is preferably 5.0 μm or less, more preferably 4.0 μm or less, and 3.0 μm or less. Further preferred. The lower limit value and upper limit value of the average minor axis of the plurality of columnar structures 123 can be appropriately combined.

  Furthermore, the average value (average major axis) of the major axis LA of the plurality of columnar structures 123 is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 1.5 μm or more. . On the other hand, the average value (average major axis) of the major axis LA of the plurality of columnar structures 123 is preferably 8.0 μm or less, more preferably 5.0 μm or less, and even more preferably 3.0 μm or less. . The lower limit value and upper limit value of the average major axis of the plurality of columnar structures 123 can be appropriately combined.

  The anisotropic optical film 100 according to the present embodiment has various characteristics at a higher level by setting the average minor axis and the average major axis of the plurality of columnar structures 113 and the plurality of columnar structures 123 within the above preferable range. An anisotropic optical film having a good balance can be obtained.

  The average value of the minor axis SA (average minor axis) and the average value of the major axis LA (average major axis) of the plurality of columnar structures 113 and the plurality of columnar structures 123 in this embodiment are the surface of the anisotropic light diffusion layer 120. Is observed with a microscope, the short diameter SA and the long diameter LA of 100 arbitrarily selected columnar structures 113 and columnar structures 123 are measured, and an average value thereof may be obtained. Further, as the aspect ratio of the columnar structure, a value obtained by dividing the average value (average major axis) of the major axis LA obtained above by the average value (average minor axis) of the minor axis SA is used.

<Thickness of region where columnar structures 113 and 123 are formed>
The thickness T of the plurality of columnar structures 113 and 123 is preferably 10 μm to 200 μm, more preferably 20 μm or more and less than 100 μm, and still more preferably 20 μm or more and less than 50 μm. When the thickness T exceeds 200 μm, not only the material cost is increased, but also the cost for UV irradiation is increased, so that not only the cost is increased, but also an increase in diffusibility in the thickness T direction causes an image blur and a decrease in contrast. It tends to happen. Further, when the thickness T is less than 10 μm, it may be difficult to achieve sufficient light diffusibility and light condensing performance. In the present invention, by setting the thickness T within the specified range, the problem of cost is reduced, the light diffusibility and the light condensing property are excellent, and the light diffusibility is decreased in the thickness T direction, thereby reducing the image. Blur is less likely to occur and the contrast can be improved.

<< Properties of Anisotropic Optical Film 100 >>
As described above, the anisotropic optical film 100 has the anisotropic light diffusion layer 110 or 120. More specifically, the anisotropic light diffusion layer 110 has a louver structure (preferably a region having a columnar region with an aspect ratio of 2 or more). The anisotropic light diffusion layer 120 has a pillar structure (preferably a region having a columnar region with an aspect ratio of less than 2). Hereinafter, the properties of the anisotropic optical film 100 will be described.

<Linear transmittance>
Here, if the linear transmittance of light incident on the anisotropic optical film 100 (anisotropic light diffusion layers 110 and 120) at the incident light angle at which the linear transmittance is maximum is defined as “maximum linear transmittance”, it is anisotropic. The optical optical film 100 (anisotropic light diffusing layers 110 and 120) preferably has a maximum linear transmittance of 20% or more, more preferably 30% or more, still more preferably 50% or more, and 70 % Or more is still more preferable, and it is still more preferable that it is less than 90%.

  Note that the linear transmittance of light incident on the anisotropic light diffusion layer 110 or 120 at the incident light angle that minimizes the linear transmittance can be defined as “minimum linear transmittance”. The minimum linear transmittance is preferably 10% or less.

  By setting the maximum linear transmittance of the anisotropic optical film 100 within the above range, the anisotropic optical film 100 can have an appropriate anisotropy, so that the application range of the anisotropic optical film 100 can be widened. For example, when the anisotropic optical film 100 is used in a display device, if the anisotropy is too strong, the light diffusion / condensation property in the MD direction is extremely excellent, but the light diffusion / condensation in the TD direction is excellent. There is a problem that the property tends to be insufficient. The anisotropic optical film 100 according to this embodiment has the above-described maximum linear transmittance, so that it maintains excellent light diffusion / condensation in the MD direction, and then diffuses light in the TD direction. It has sufficient light collecting properties.

  Here, the linear transmitted light amount and the linear transmittance can be measured by the method shown in FIG. That is, the linear transmitted light amount and the linear transmittance are measured for each incident light angle so that the rotation axis V shown in FIG. 3 coincides with the CC axis shown in FIGS. 6A and 6B (the normal direction is 0). °). An optical profile is obtained from the obtained data, and the maximum linear transmittance and the minimum linear transmittance can be obtained from the optical profile.

  Moreover, the maximum linear transmittance and the minimum linear transmittance in the anisotropic optical film 100 (the anisotropic light diffusion layers 110 and 120) can be adjusted by design parameters at the time of manufacture. Examples of the parameters include the composition of the coating film, the film thickness of the coating film, the temperature to the coating film given during structure formation, and the like. The composition of the coating film changes the maximum linear transmittance and the minimum linear transmittance by appropriately selecting and preparing the constituent components. In the design parameter, the maximum linear transmittance and the minimum linear transmittance tend to be lower as the film thickness is thicker, and higher as the film thickness is thinner. The maximum linear transmittance and the minimum linear transmittance tend to be lower as the temperature is higher, and higher as the temperature is lower. Each of the maximum linear transmittance and the minimum linear transmittance can be appropriately adjusted by a combination of these parameters.

<Diffusion width>
By the above method, the maximum linear transmittance and the minimum linear transmittance of the anisotropic optical film 100 are obtained, and the linear transmittance of an intermediate value between the maximum linear transmittance and the minimum linear transmittance is obtained. Two incident light angles with respect to the linear transmittance of the intermediate value are read. In the optical profile, the normal direction is 0 °, and the incident light angle is shown in the minus direction and the plus direction. Therefore, the incident light angle and the incident light angle corresponding to the intersection may have a negative value. If the value of the two intersections has a positive incident light angle value and a negative incident light angle value, the sum of the absolute value of the negative incident light angle value and the positive incident light angle value is the diffusion of the incident light. It becomes the diffusion width, which is the angular range of the region. When the values of the two intersections are both positive, the difference obtained by subtracting the smaller value from the larger value is the diffusion width that is the angle range of the incident light angle. When the values of the two intersections are both negative, the absolute value of each is taken, and the difference obtained by subtracting the smaller value from the larger value is the diffusion width that is the angle range of the incident light angle.

  In the anisotropic optical film 100, the width of the diffusion region (diffusion width), which is the angle range of two incident light angles with respect to the linear transmittance of the intermediate value between the maximum linear transmittance and the minimum linear transmittance, is MD direction. It is preferably 10 ° or more and less than 70 °, and more preferably 30 ° or more and less than 50 °. In the TD direction, it is preferably 5 ° or more and less than 50 °, and more preferably 20 ° or more and less than 30 °. When it is out of the specified range, that is, when the diffusion width becomes too wide, the light condensing property is weakened. When the diffusion width is too narrow, the display property and visibility are lowered due to the weakening of the diffusivity. Resulting in. That is, according to the present invention, since the diffusion width is within the specified range, it is possible to balance the diffusibility and the light condensing property, and to further enhance the effect of suppressing a rapid change in luminance.

<Scattering central axis>
Next, the scattering center axis P in the anisotropic light diffusion layer will be described with reference to FIG. FIG. 7 is a three-dimensional polar coordinate display for explaining the scattering center axis P in the anisotropic optical film 100 (anisotropic light diffusion layer).

  The anisotropic light diffusing layer has at least one scattering central axis. As described above, the scattering central axis has a light diffusibility when the incident light angle to the anisotropic light diffusing layer is changed. Means a direction coinciding with the incident light angle of light having substantially symmetry with respect to. Note that the incident light angle at this time is a substantially central portion (central portion of the diffusion region) sandwiched between the minimum values in the optical profile obtained by measuring the optical profile of the anisotropic light diffusion layer.

  Further, according to the three-dimensional polar coordinate display as shown in FIG. 7, the scattering central axis is defined as polar angle θ and azimuth angle when the surfaces of the anisotropic light diffusion layers 110 and 120 are the xy plane and the normal is the z axis. It can be expressed by φ. That is, it can be said that Pxy in FIG. 7 is the length direction of the scattering central axis projected on the surface of the anisotropic light diffusion layer.

  Here, the anisotropic light diffusion layer 110 has a columnar region 113, and the anisotropic light diffusion layer 120 has a columnar region 123. Polar angle θ (−90 ° <θ <90 °) formed by the normal line (z axis shown in FIG. 7) of the anisotropic light diffusion layer (anisotropic light diffusion layer 110 or 120) and the columnar region 113 (columnar region 123). Is defined as the scattering center axis angle in this embodiment, the absolute value of the difference between the scattering center axis angle of the columnar region 113 and the scattering center axis angle of the columnar region 123 is preferably 0 ° or more and 30 ° or less. By setting the absolute value of the difference in scattering center axis angle within the above range, the effect of the present invention can be further enhanced. In order to realize this effect more effectively, the absolute value of the difference between the scattering center axis angle of the columnar region 113 and the scattering center axis angle of the columnar region 123 is more preferably 0 ° or more and 20 ° or less, More preferably, the angle is 10 ° or more and 20 ° or less. In addition, the scattering center axis angles of the columnar region 113 and the columnar region 123 are adjusted to a desired angle by changing the direction of the light beam applied to the composition containing the sheet-like photopolymerizable compound when manufacturing them. can do.

  In addition to the fact that the absolute value of the difference in the scattering center axis angle (polar angle) satisfies the above range, the difference between the azimuth angle of the scattering center axis of the columnar region 113 and the azimuth angle of the scattering center axis of the columnar region 123. The absolute value of is preferably 0 ° or more and 20 ° or less. Thereby, the width of the diffusion region can be further increased without reducing the linear transmittance in the non-diffusion region of the anisotropic optical film 100.

  Here, each of the anisotropic light diffusion layers 110 and 120 may include a plurality of columnar region groups having different inclinations (a set of columnar regions having the same inclination) in a single layer. The lower limit of the absolute value of the difference in scattering center axis angle is more preferably 5 °. On the other hand, the upper limit of the absolute value of the difference in scattering center axis angle is more preferably 20 °, and further preferably 15 °.

  Further, the polar angle θ (that is, the scattering center axis angle) of the scattering center axis P of the columnar region 113 and the columnar region 123 is preferably ± 0 to 60 °, and more preferably ± 0 to 30 °. When the scattering center axis angle is greater than + 60 ° and less than −60 °, contrast and brightness cannot be sufficiently improved.

<Refractive index>
The anisotropic light diffusion layers 110 and 120 are obtained by curing a composition containing a photopolymerizable compound. As the composition, the following combinations can be used.
(1) Using a single photopolymerizable compound (2) Using a mixture of a plurality of photopolymerizable compounds (3) A single or a plurality of photopolymerizable compounds, and a polymer compound not having photopolymerizability Used in combination

  In any of the above combinations, it is presumed that a micron-order fine structure with a different refractive index is formed in the anisotropic light diffusion layers 110 and 120 by light irradiation. It is thought that anisotropic light diffusion characteristics are exhibited. Therefore, in the above (1), it is preferable that the refractive index change is large before and after the photopolymerization. In (2) and (3), it is preferable to combine a plurality of materials having different refractive indexes. Here, the refractive index change and the refractive index difference specifically indicate a change or difference of 0.01 or more, preferably 0.05 or more, more preferably 0.10 or more.

  In FIG. 8, the display light L irradiated from the light irradiation unit 31 provided in the HUD device 3 is incident on or enters the above-described anisotropic optical film (anisotropic light diffusion layer) 100 and is regularly reflected. It is a figure explaining the arrangement | positioning relationship between the light angle, ie, the light irradiation part 31, and the anisotropic optical film (anisotropic light-diffusion layer) 100. FIG.

  The anisotropic optical film (anisotropic light diffusing layer) 100 is compared with the linear transmittance when the light is incident in the scattering central axis direction (the incident light angle in this direction is 0 °, for example, P shown in FIG. 8). Thus, the linear transmittance once reaches a minimum value at an incident light angle of −20 ° to 20 °. That is, in the anisotropic optical film (anisotropic light diffusion layer) 100, incident light is strongly diffused in an incident light angle range of -20 ° to 20 ° close to the scattering central axis direction (light diffusion takes precedence). .

  On the other hand, the anisotropic optical film (anisotropic light diffusion layer) 100 has a linear transmittance when incident in the scattering central axis direction (the incident light angle in this direction is 0 °, for example, P shown in FIG. 8). In comparison, the linear transmittance becomes a maximum value at an incident light angle of −60 to −30 ° or + 30 ° to + 60 °. That is, in the anisotropic optical film (anisotropic light diffusion layer) 100, the diffusion is weakened and the linear transmittance is increased in the incident light angle range of −20 to + 20 ° or more (light transmission is given priority).

  Based on such properties of the anisotropic optical film (anisotropic light diffusion layer) 100, the arrangement relationship between the light irradiation unit 31 provided in the HUD device 3 and the anisotropic optical film (anisotropic light diffusion layer) 100 is defined. There is a need to.

  As shown in FIG. 8, the straight line of the anisotropic optical film (anisotropic light diffusion layer) 100 with reference to the incident light angle incident in the scattering central axis direction P (the incident light angle in this direction is 0 °). The difference between the incident light angle at which the transmittance is minimum (see FIG. 4) and the incident light angle at which the display light L irradiated from the light irradiation unit 31 is incident on the anisotropic optical film (anisotropic light diffusion layer) 100. Is within the range of -20 to 20 °. Alternatively, the linear transmittance of the anisotropic optical film (anisotropic light diffusion layer) 100 is minimized with reference to the incident light angle incident in the scattering central axis direction P (the incident light angle in this direction is 0 °). The incident light angle (see FIG. 4) and the regular reflection light that the display light L irradiated from the light irradiation unit 31 is reflected with respect to the incident light incident on the anisotropic optical film (anisotropic light diffusion layer) 100 The difference from the angle needs to be within a range of −20 ° to + 20 °.

  That is, as shown in FIG. 8, when the incident light angle side is + and the specular reflection light angle side is −, the incident light angle incident in the scattering central axis direction P (the incident light angle in this direction is 0 °). With respect to the incident light angle at which the linear transmittance of the anisotropic optical film (anisotropic light diffusion layer) 100 is minimized, and the anisotropic optical film (anisotropic light diffusion) of the display light L emitted from the light irradiation unit 31. The difference between the incident light angle incident on the layer) 100 or the regular reflection light angle needs to be within a range of −20 ° to + 20 °.

  Thus, by arranging the light irradiation unit 31 and the anisotropic optical film (anisotropic light diffusion layer) 100 in the HUD device 3 based on the above relationship, the display light L is in the scattering central axis direction P. Nearly, for example, the display light L incident in the incident light angle range of −20 ° to + 20 ° is strongly diffused, and the diffused light is in a predetermined range corresponding to the incident light angle range (for example, −20 ° to + 20 °). As a result, it is difficult for image blur to occur, and the contrast can be improved. On the other hand, when external light is incident from other than ± 20 °, the external light is transmitted through the anisotropic optical film (anisotropic light diffusion layer) 100 while maintaining the incident direction, and the reflecting member 32. Therefore, it is guided in a direction away from the light irradiation unit 31 and is less likely to be incident on the front surface of the light irradiation unit 31. Thereby, the influence of external light can be reduced sufficiently. As a result, sufficient visibility can be ensured by sufficiently reducing the influence of external light and increasing the contrast. In the following, it is assumed that all are based on the incident light angle, the regular reflection light angle, and the positive and negative signs in FIG.

  FIG. 9 is a diagram illustrating a state in which external light M such as sunlight is transmitted by the anisotropic light diffusion layer 100 provided on the reflection member 32 in the HUD device 3.

  As described above, the anisotropic optical film (anisotropic light diffusion layer) 100 is compared with the linear transmittance in the case of incidence in the scattering central axis direction (incident light angle in this direction is 0 °). The linear transmittance once reaches a minimum value at an incident light angle of −20 ° to + 20 °, and the linear transmittance increases as the incident light angle (absolute value) increases, and −60 ° to −30 ° or +30. A valley-shaped optical profile in which the linear transmittance becomes maximum at an incident light angle of ° to + 60 ° is shown.

  As described above, in the anisotropic optical film (anisotropic light diffusion layer) 100, incident light is strongly diffused in the incident light angle range of −20 ° to + 20 ° close to the scattering central axis direction (light diffusion takes precedence). ), In the incident light angle range beyond that, the diffusion is weakened and the linear transmittance is increased (light transmission is given priority).

  First, as shown in FIG. 9, the incident light angle of the display light L irradiated from the light irradiation unit 31 with respect to the scattering center axis direction of the anisotropic optical film (anisotropic light diffusion layer) 100 is, for example, about 10 °. To do.

  In this case, the display light L irradiated from the light irradiation unit 31 is in the incident light angle range of −20 ° to + 20 ° close to the scattering central axis direction. Within this range, the diffusion of light is given priority because it is a highly diffusive range. For this reason, the display light L is strongly diffused, and the diffused light is diffused in a predetermined range (for example, −20 ° to + 20 °) corresponding to the incident light angle range. As a result, the diffused display light L is irradiated (projected, projected) only to a predetermined range on the windshield 40. Thereby, since the diffusibility and the light condensing property are balanced, the display image can be clearly irradiated (projected or projected) on the windshield 40 without blurring (improving contrast).

  Next, the incident light angle of the external light M such as sunlight entering through the windshield 40 with respect to the scattering center axis direction of the anisotropic optical film (anisotropic light diffusion layer) 100 is set to about 50 °, for example.

  In this case, the external light M is in the incident light angle range of −60 ° to −30 ° or + 30 ° to + 60 ° apart from the scattering central axis direction. Within this range, the diffusibility is weakened, the linear transmittance is large (maximum), and light transmission is given priority. For this reason, the external light M is transmitted through the anisotropic optical film (anisotropic light diffusion layer) 100 while maintaining the incident direction. As a result, the external light M transmitted through the anisotropic optical film (anisotropic light diffusion layer) 100 is regularly reflected by the reflecting member 32. For this reason, the external light M is guided in a direction away from the light irradiation unit 31 and is not easily incident on the front surface of the light irradiation unit 31. Thereby, the influence of external light can be reduced sufficiently.

  Thus, by using the anisotropic optical film (anisotropic light diffusion layer) 100 having the incident light angle dependency that has both directivity and anisotropy, while sufficiently reducing the influence of external light, The contrast can be increased.

(Second Embodiment)
The HUD device 3 according to the second embodiment will be described with reference to FIG. The second embodiment is different from the first embodiment in that the diffusion member 60 is provided on the anisotropic light diffusion layer 100 (on the display light or external light incident side). In addition, the same structure and the same structure part as 1st Embodiment attach | subject and demonstrate the same code | symbol.

  As described above, the light irradiation unit 31 is provided in the housing 30 of the HUD device 3. When the amount of external light is larger than the amount of virtual image displayed by the light irradiation unit 31, the display of the virtual image may be difficult to visually recognize due to the influence of external light. For this reason, when the light amount (luminance) from the light irradiation unit 31 is increased (intensified), the light amount of the display light L from the light irradiation unit 31 is reflected by the reflecting member 32 and the anisotropic light diffusion layer 100 diffuses light excessively. (Scattering) causing hot spots (bright spots). When a hot spot (bright spot) is generated on the windshield 40, it appears as glaring, becomes dazzling, and causes a decrease in visibility.

  Therefore, by providing the diffusing member 60 on the anisotropic light diffusing layer 100 as in the second embodiment, the display light L diffused by the anisotropic light diffusing layer 100 is further diffused by the diffusing member 60. The diffusibility is increased and the cause of hot spots (bright spots) can be suppressed.

  The diffusing member 60 is a diffusing film, a diffusing plate, a diffusing layer, or the like, and may have any diffusibility at a certain angle when external light is incident thereon, and its shape and configuration are not particularly limited.

  In addition, between the diffusing member 60 and the anisotropic optical film (anisotropic light diffusing layer) 100 or between the anisotropic optical film (anisotropic light diffusing layer) 100 and the reflecting member 32, respectively, for example, transparent adhesive What is necessary is just to laminate | stack via a layer (not shown).

(Third embodiment)
A HUD device 3 according to a third embodiment will be described with reference to FIG. The third embodiment is that the polarizing member 70 is provided on the diffusing member 60 as compared with the second embodiment. In addition, the same structure and the same structure part as 1st, 2nd embodiment attach | subject and demonstrate the same code | symbol.

  As described above, for example, in a situation where strong external light comes from the sun, such as during daytime in fine weather, the amount of external light is larger than the amount of virtual image displayed by the HUD device 3, The display of the virtual image may be difficult to visually recognize due to the influence of external light. That is, the external light M incident from the outside of the windshield 40 is reflected by the reflecting member 32 and reaches the light irradiation unit 31, and the display image becomes relatively thin. As a result, the virtual image 50 becomes difficult to see. There is a problem of causing a phenomenon (so-called washout).

  Therefore, as in the third embodiment, by providing the polarizing member 70 on the diffusing member 60, the light amount of external light such as sunlight incident through the windshield 40 is basically 50%. However, since the light is absorbed by the polarizing member 70 and reduced to about half, the amount of external light incident on the front surface of the light irradiation unit 31 is also reduced to about half, and the reduction in visual recognition of the display image due to external light can be suppressed.

  In the third embodiment, in addition to the polarizing member 70, the diffusing member 60 and the anisotropic light diffusing layer 100 are provided. Since the diffusing member 60 is provided, the external light that has passed through the polarizing member 70 is diffused by the diffusing member 60, so that the amount of external light incident on the front surface of the light irradiation unit 31 can be further reduced. .

  Furthermore, by providing the anisotropic light diffusion layer 100, the external light diffused by the diffusion member 60 reaches the front surface of the light irradiation unit 31 according to the incident light angle to the anisotropic light diffusion layer 100. It becomes possible to eliminate. As a result, it is possible to further reduce the amount of incident external light, and to further suppress the reduction in the visibility of the display image due to external light.

  The polarizing member 70 is a polarizing plate, a polarizing film, or the like. Moreover, it is a polarizer which reflects the polarized light of the specific direction contained in external lights, such as sunlight, for example, can be comprised with a wire grid polarizer. The polarizing member 70 is not limited to this, and may be any member that polarizes external light such as sunlight in a specific direction and absorbs (blocks) light other than the light polarized in the specific direction. Further, the shape and configuration are not particularly limited.

  The polarizing member 70 is not necessarily used at the same time as the diffusing member 60. For example, only the combination of the anisotropic light diffusing layer 100 and the polarizing member 70 may be used.

(Fourth embodiment)
A HUD device 3 according to a fourth embodiment will be described with reference to FIG. The fourth embodiment is that an anisotropic light diffusion layer 400 is provided below the windshield 40 in contrast to the first embodiment. In addition, the same structure and the same structure part as 1st-3rd embodiment attach | subject and demonstrate the same code | symbol. The anisotropic light diffusion layer 400 will be described as being similar to the anisotropic light diffusion layer 100 described above.

  As described above, the light irradiation unit 31 is provided in the housing 30 of the HUD device 3. When the display light L from the light irradiation unit 31 is applied to the windshield 40, the display light L from the light irradiation unit 31 is reflected light (virtual image light) reflected by the inner surface (driver side) of the windshield 40. And may be recognized by the driver's naked eye, and may be recognized by receiving both reflected light (double virtual image light) that has entered the outer surface of the windshield 40 and reflected. Therefore, in such a case, the visibility of the display image is reduced.

  Therefore, when the display light L from the light irradiation unit 31 is irradiated on the windshield 40 by providing the above-described anisotropic light diffusion layer 400 below the windshield 40 as in the fourth embodiment, the display light is displayed. L is diffused by the anisotropic light diffusion layer 400. Moreover, since the anisotropic light diffusion layer 400 can balance the diffusibility and the light condensing property, double virtual image light can be prevented and contrast can be improved. Furthermore, it is possible to prevent the display image from being visually recognized when strong external light such as sunlight enters from a specific direction.

  In addition, the anisotropic light diffusion layer 100 is provided on the reflection surface side of the reflection member 32, and the anisotropic light diffusion layer 400 is provided below the windshield 40. As a result, the display light L from the light irradiation unit 31 can further balance the diffusibility and the light condensing property according to the incident light angle, so that the image blur is prevented while preventing the double virtual image light. Is less likely to occur and the contrast can be improved. On the other hand, external light is diffused by the anisotropic light diffusion layer 400 according to the incident light angle, and the diffused diffused light is further diffused by the anisotropic light diffusion layer 100 according to the incident light angle. The light irradiation unit 31 is guided away from the light irradiation unit 31 and is less likely to be incident on the front surface of the light irradiation unit 31. Thereby, the influence of external light can be reduced sufficiently.

  The anisotropic light diffusion layer 400 may be provided in a partial region of the windshield 40, or may be provided in the entire windshield 40. The anisotropic light diffusing layer 400 is not necessarily used at the same time as the anisotropic light diffusing layer 100, and only the anisotropic light diffusing layer 400 may be used. The anisotropic light diffusion layer 400 can be a known anisotropic light diffusion layer.

(Fifth embodiment)
A HUD device 3 according to a fifth embodiment will be described with reference to FIG. In the fifth embodiment, the display light L emitted from the light irradiation unit 31 in the first embodiment is changed from the projection area 41 to the combiner 34 instead of the windshield 40. In addition, the same structure and the same structure part as 1st-4th embodiment attach | subject and demonstrate the same code | symbol.

  The HUD device 3 is accommodated inside an instrument panel (not shown) (not shown). The HUD device 3 includes a housing 30 and an opening 33 provided in a part of the housing 30, and the display light L can be emitted from the opening 33 toward the outside of the instrument panel. it can.

  As shown in FIG. 13, a thin plate-shaped combiner 34 that stands up in a slightly inclined state is installed above the housing 30 or on the instrument panel. The combiner 34 is an optical element and has functions of light reflection, transmission, and synthesis. That is, the combiner 34 reflects the light incident on the right surface and guides it to the eye point (viewpoint) EP, and transmits the light incident on the left surface and guides it to the eye point (viewpoint) EP. Therefore, the light incident on the windshield 40 from the outside and transmitted through the combiner 34 and the light irradiated from the HUD device 3 and reflected by the combiner 34 are combined and imaged at an eye point (viewpoint) EP. Note that the combiner 34 may be provided above the housing 30 or in a part of the instrument panel, or may be provided above the housing 30 or in the entire instrument panel.

  A light irradiation unit 31 is provided in the HUD device 3. The light irradiation unit 31 is a member that irradiates display light L representing a display image, and includes, for example, a liquid crystal display with a backlight (not shown). The display image of the liquid crystal display is illuminated by a backlight and illuminated (projected, projected) toward the right side. This projection light is reflected by the surface of the reflecting member 32 and travels toward the surface of the combiner 34 disposed outside the opening 33.

  Therefore, the irradiation light (projection light) corresponding to the display image of the liquid crystal display passes through the optical path passing through the liquid crystal display, the anisotropic light diffusion layer 100, the reflecting member 32, the anisotropic light diffusion layer 100, and the combiner 34 in order. Viewpoint) Focused on EP. Actually, since the image reflected by the combiner 34 and the reflecting member 32 is formed, the image viewed by the driver at the eye point can be viewed as a virtual image 50 ahead of the combiner 34 and the windshield 40. .

  Here, since the shape and inclination of the windshield 40 differ depending on the vehicle type or the like, the optimum polarization direction of light differs for each vehicle. For example, the windshield of a small vehicle has a larger inclination angle with respect to the instrument panel than the windshield of a large vehicle. In addition, in a vehicle having a relatively small space in the instrument panel, such as a small vehicle, when the HUD device 3 is mounted in the instrument panel, the display is provided on the front side of the steering to display various vehicle information. The part (combination meter) is driven to the rear side of the vehicle (in the direction opposite to the driver side of the instrument panel). If it does so, it will become easy to produce the reflection of the light outside a vehicle to a display part (combination meter), or the reflection from the display part (combination meter) to the windshield 40 or a side window. For this reason, in the case of a small vehicle, it is more preferable to use a combiner.

  It should be noted that the above-described embodiment should not be construed as being limited to being applied to a specific object, and may be any combination.

  For example, the reflecting member 32, the anisotropic light diffusing layer 100, and the diffusing member 60 shown in FIG. 10 may be combined with the anisotropic light diffusing layer 400 provided below the windshield 40 shown in FIG. Further, the reflecting member 32, the anisotropic light diffusing layer 100, the diffusing member 60 shown in FIG. 10 and the combiner 34 shown in FIG. 13 may be combined. Furthermore, the reflecting member 32, the anisotropic light diffusing layer 100, the diffusing member 60, and the polarizing member 70 shown in FIG. 11 may be combined with the anisotropic light diffusing layer 400 provided below the windshield 40 shown in FIG. . Furthermore, the reflecting member 32, the anisotropic light diffusing layer 100, the diffusing member 60, and the polarizing member 70 shown in FIG. 11 and the combiner 34 shown in FIG. 13 may be combined.

  1 shows an example in which one anisotropic light diffusing layer 100 is provided on the reflecting surface side of the reflecting member 32. However, the present invention is not limited to this. For example, the anisotropic light diffusing layer 100 is provided on the reflecting surface side of the reflecting member 32. It is good also as a structure which laminates | stacks two (or more). As described above, in the anisotropic light diffusion layer 100, the display light L incident in the −20 ° to + 20 ° incident light angle range close to the scattering central axis direction is strongly diffused, and the diffused light is in the incident light angle range. Is diffused by a predetermined range (for example, −20 ° to + 20 °). By stacking, for example, two anisotropic light diffusion layers 100 having this property, the diffused display light L is irradiated (projected, projected) only to a predetermined range on the windshield 40. As a result, it is possible to further balance the diffusibility and the light condensing property according to the incident light angle, so that it is difficult for image blur to occur while performing diffusion to suppress hot spots (bright spots), and , The contrast can be improved. Furthermore, the influence of external light can be further reduced.

  Further, when the HUD device 3 is applied to an automobile, the arrangement relationship between the windshield 40, the light irradiation unit 31 provided in the HUD device 3, and the reflecting member 32 is fixed. The fact that the positional relationship is fixed means that the incident light angle of the external light M or the display light L incident on the reflecting member 32 through the windshield 40 does not change.

  Under such circumstances, it is meaningful to use an anisotropic optical film (anisotropic light diffusion layer) 100 having incident light angle dependency. That is, by using the anisotropic optical film (anisotropic light diffusion layer) 100 having both directivity and anisotropy, the display light L representing the display image irradiated from the light irradiation unit 31 The display light L incident in the incident light angle range of −20 ° to + 20 ° close to the axial direction is strongly diffused, and the diffused light has a predetermined range corresponding to the incident light angle range (for example, −20 ° to + 20 °). That is, since the diffusibility and the light condensing property are balanced according to the incident light angle, the image blur hardly occurs and the contrast can be improved. On the other hand, the external light M is transmitted through the anisotropic optical film (anisotropic light diffusion layer) 100 while maintaining the direction of incidence according to the incident light angle, and is regularly reflected by the reflecting member 32. The external light M is guided in a direction away from the light irradiation unit 31 and is not easily incident on the front surface of the light irradiation unit 31. Thereby, the influence of external light can be reduced sufficiently.

  In this embodiment, the anisotropic optical film (anisotropic light diffusion layer) 100 includes a louver structure anisotropic optical film (anisotropic light diffusion layer) 110 (20) and a pillar structure anisotropic optical film. (Anisotropic light diffusion layer) 120 (10) is described. As described above, when the HUD device 3 is mounted on a vehicle, the display position of the virtual image 50 on the windshield 40 is an arrangement relationship between the windshield 40 and the HUD device 3, that is, the windshield 40 and the HUD device. 3 is fixed by the arrangement relationship between the light irradiation unit 31 and the reflection member 32 provided in the interior 3. For this reason, it may be difficult to cope with variations in the height position of the driver's eye point (viewpoint) EP. Note that the variation in the height position of the driver's eye point (viewpoint) EP may be caused by the height of the driving user when the vehicle is used by a plurality of users, for example.

  Here, in the anisotropic optical film (anisotropic light diffusion layer) 110 (20) having a louver structure, the transmitted light has a substantially needle shape, as can be understood by looking at the state of the transmitted light in FIG. Therefore, the light diffusibility is greatly different between the MD direction and the TD direction. That is, in the anisotropic optical film 20 having a louver structure, diffusion has anisotropy. Specifically, in the example shown in FIG. 2, diffusion is wider in the MD direction than in the case of the pillar structure, but diffusion is narrower in the TD direction than in the case of the pillar structure.

  Utilizing this property, for example, the vehicle front-rear direction and the MD direction (the minor axis SA side of the columnar region 113 in FIG. 6) are matched, and the vehicle width direction and the TD direction (the major axis of the columnar region 113 in FIG. 6). The louver-structure anisotropic optical film (anisotropic light diffusion layer) 110 (20) is provided on the reflecting surface side of the reflecting member 32 in FIG.

  In this way, since the virtual image 50 is displayed on the windshield 40 in the range of substantially needle-shaped transmitted light, the occupant can minimize the movement of the line of sight when viewing the display image. It is possible to reduce the burden during driving. That is, it is possible to cope with variations in the height position of the driver's eye point (viewpoint) EP.

  Further, in the present embodiment, the HUD device 3 has been described as being housed inside the instrument panel in the downward direction of the windshield 40, but the housing portion inside the instrument panel constitutes the instrument panel. When the light irradiation part 31, the reflection member 32, etc. are arrange | positioned in this member and this accommodating part is arrange | positioned, the accommodating part formed in the panel member which comprises an instrument panel is used for this embodiment. The housing 30 may be used. In this case, the anisotropic optical film (anisotropic light diffusion layer) 100 of the present embodiment is disposed in the opening window provided in the instrument panel member.

  In the present embodiment, the HUD device 3 has been described as being applied to an automobile. However, the present invention is not limited to this. For example, an aircraft, a train, a construction vehicle, a game device (for example, display of a pachinko, a slot, etc.) It may be used in game devices, medical devices, and the like.

  Next, although an example and a comparative example explain the present invention still more concretely, the present invention is not limited at all by these examples.

<< Manufacture of anisotropic optical film >>
The anisotropic optical film of the present invention was produced by an existing method described below (for example, JP-A-2006-119241).

<Pillar structure>
A partition wall having a height of 0.2 mm was formed with a curable resin on the entire periphery of the edge of a PET film (trade name: A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 75 μm and a size of 76 × 26 mm. The following ultraviolet curable resin composition was dropped into this and covered with another PET film.
-50 parts by weight of 2- (perfluorooctyl) -ethyl acrylate (61% fluorine content, manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate FA-108)
・ 50 parts by weight of 1,9-nonanediol diacrylate (fluorine-free, manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light acrylate 1.9ND-A)
-4-Hydroxy-2-methyl-1-phenylpropan-1-one 4 parts by weight (Ciba Specialty Chemicals, trade name: Darocur 1173)
An irradiation intensity of 30 mW is perpendicular to the epi-illumination irradiation unit of a UV spot light source (manufactured by Hamamatsu Photonics, Inc., product name: L2859-01) with respect to a liquid film having a thickness of 0.2 mm sandwiched between the PET films. An anisotropic light diffusing layer having many rod-like minute regions as shown in FIG. 2 (a) or FIG. 6 (b) was obtained by irradiating with ultraviolet rays which are parallel rays of / cm ² for 1 minute.

<Louvre structure>
A directional diffusing element in which an ultraviolet ray of a parallel ray emitted from an epi-illumination irradiation unit of the UV spot light source has an aspect ratio of a transmitted ray of 25 to an ultraviolet curable composition sandwiched between the same PET films as the pillar structure A substantially plate-like region having a different refractive index as shown in FIG. 2 (b) or FIG. 6 (a) is irradiated perpendicularly with the ultraviolet rays of the linear rays converted through the above-mentioned pillar structure at the same irradiation intensity as that of the pillar structure. An anisotropic light diffusing layer having was obtained.

  Here, the anisotropic light diffusion layers used in the examples described below are of two types, the pillar structure and the louver structure described above, and each exhibit optical characteristics having the linear transmittance shown in FIG. Each scattering center axis is about 0 ° with respect to the normal, and the diffusion width is about −20 ° to + 20 ° with respect to the scattering center axis.

  Moreover, the diffusion member used for the Example demonstrated below prepared the isotropic diffusion film and the directional diffusion film. The isotropic diffusion film used is Light Up UK4 (Haze: about 46%) manufactured by Kimoto Co., and the directional diffusion film used is LSD manufactured by Optical Solutions Co., Ltd. (half-value angle of diffusion indicating directivity is about 5 °). .

  Further, when using a polarizing member in the examples described below, a plastic polarizing plate is used, and when using an anisotropic light diffusion layer on the windshield, the above-described anisotropic light diffusion layer having a louver structure is used. It was.

<Evaluation equipment>
As an HUD apparatus used for the evaluation of the examples described below, an incident light angle of display light emitted from the LCD projector is applied to the reflective member having the anisotropic light diffusion layer of the present embodiment using the LCD projector method. Was arranged at a position of about + 15 ° from the plane normal line of the anisotropic light diffusion layer. The display light was reflected around about −15 °, which is the regular reflection light angle of the anisotropic light diffusion layer, and displayed on a transparent glass plate as a windshield.

Example 1
The reflective member was provided with an anisotropic light diffusing layer having a pillar structure, and the evaluation was performed with the evaluation device described above. The evaluation conditions of Example 1 are shown in Table 1, and the results of evaluating optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

(Example 2)
The reflective member was provided with an anisotropic light diffusion layer having a louver structure, and the evaluation was performed using the evaluation apparatus described above. The evaluation conditions of Example 2 are shown in Table 1, and the results of evaluating the optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

(Example 3)
A reflective member is provided with an anisotropic light diffusion layer having a louver structure, and an isotropic diffusion film <Light Up UK4 (Haze: about 46%) manufactured by Kimoto Co., Ltd.> is provided on the anisotropic light diffusion layer having a louver structure. Evaluation was performed. The evaluation conditions of Example 3 are shown in Table 1, and the results of evaluating optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

Example 4
A reflective member is provided with an anisotropic light diffusion layer having a louver structure, and a directional diffusion film <Optical Solutions LSD (a half-value angle of diffusion indicating directivity is about 5 °)> on the anisotropic light diffusion layer having a louver structure> It provided and evaluated with the evaluation apparatus mentioned above. The evaluation conditions of Example 4 are shown in Table 1, and the results of evaluating optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

(Example 5)
The reflective member is provided with an anisotropic light diffusion layer having a pillar structure, and an isotropic diffusion film <Light Up UK4 (Haze: about 46%) manufactured by Kimoto Co., Ltd.> is provided on the anisotropic light diffusion layer having a pillar structure. Evaluation was performed. The evaluation conditions of Example 5 are shown in Table 1, and the results of evaluating the optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

(Example 6)
An anisotropic light diffusion layer having a pillar structure is provided on the reflecting member, and an isotropic diffusion film <Light Up UK4 (Haze: about 46%) manufactured by Kimoto Co., Ltd.> is provided on the anisotropic light diffusion layer having a pillar structure. A polarizing plate was provided on the film, and evaluation was performed using the above-described evaluation apparatus. The evaluation conditions of Example 6 are shown in Table 1, and the results of evaluating optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

(Example 7)
An anisotropic light diffusion layer having a pillar structure is provided on the reflecting member, and an isotropic diffusion film <Light Up UK4 (Haze: about 46%) manufactured by Kimoto Co., Ltd.> is provided on the anisotropic light diffusion layer having a pillar structure. A polarizing plate was provided on the film. Moreover, after providing the anisotropic light-diffusion layer of the louver structure in the windshield lower surface, it evaluated by the evaluation apparatus mentioned above. The evaluation conditions of Example 7 are shown in Table 1, and the results of evaluating optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

(Comparative Example 1)
The reflection member was evaluated using the above-described evaluation apparatus. The evaluation conditions of Comparative Example 1 are shown in Table 1, and the results of evaluating the optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

(Comparative Example 2)
The reflective member was provided with an isotropic diffusion film <Light Up UK4 (Haze: about 46%) manufactured by Kimoto Co., Ltd.> and evaluated with the above-described evaluation apparatus. The evaluation conditions of Comparative Example 2 are shown in Table 1, and the results of evaluating the optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

(Comparative Example 3)
The reflective member was provided with a directional diffusion film <LSD manufactured by Optical Solutions Inc. (half-value angle of diffusion indicating directivity is about 5 °)>, and evaluation was performed using the above-described evaluation apparatus. The evaluation conditions of Comparative Example 3 are shown in Table 1, and the results of evaluating the optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

(Comparative Example 4)
The reflective member is provided with a directional diffusion film <LSD manufactured by Optical Solutions Inc. (a half-value angle of diffusion indicating directivity is about 5 °)>, and a polarizing plate is provided on the directional diffusion film. Evaluation was performed. The evaluation conditions of Comparative Example 4 are shown in Table 1, and the results of evaluating the optical characteristics and the like (hot spot, luminance, contrast, viewing angle) under the evaluation conditions shown in Table 1 are shown in Table 2.

<< Evaluation method >>
The anisotropic optical films of the above examples and comparative examples were evaluated as follows.

  Visual evaluation from the viewpoint of visibility (evaluation items) regarding presence / absence of hot spots caused by backlight light source of LCD projector, brightness (light and dark places), contrast (dark places), and viewing angle (eye point) went. Specifically, the evaluation was performed using the average of the scores of 10 viewers (maximum 5 points for each item).

<Scoring criteria for evaluation items>
The scoring criteria for each evaluation item in Table 2 are as follows.
"Hot spot"
1 (strongly present) to 5 (none)
"Brightness (light and dark)"
1 (dark) to 5 (bright)
"Contrast (dark place)"
1 (low) to 5 (high)
"Viewing angle (eye point)"
(Narrow) to 5 (wide)

<< Evaluation results >>
The examples had a high level of characteristics with a total balance (total score) of 13 or more in all evaluation items in a well-balanced manner. On the other hand, all of the comparative examples had very bad results with a total (total score) of less than 10.

  More specifically, as shown in Table 2, the anisotropic optical films of the examples have all evaluation items of hot spot, luminance (bright place and dark place), contrast (dark place), and viewing angle (eye point). Had a high level of properties in a well-balanced manner. In Example 1, the luminance and contrast were excellent at a high level, and in Example 2, the luminance and viewing angle were excellent at a high level. Moreover, in Example 3 and Example 4, the point which was able to reduce a hot spot was ensured, ensuring a brightness | luminance. Further, Example 5 is excellent in that the hot spot can be reduced while ensuring the luminance, and Example 6 is excellent in that the hot spot is given the highest point while improving the contrast. In particular, in Example 7, the hot spots, contrasts, and viewing angles had the highest points and had very high level characteristics. On the other hand, some of the comparative examples have evaluations superior to the examples in specific items (for example, luminance). However, as in the examples, hot spots, luminance (light and dark places), contrast None of the evaluation items (dark place) and viewing angle (eye point) had high levels.

  Therefore, when the anisotropic optical film of the example is used in, for example, a HUD device, it has excellent display characteristics (brightness, contrast, etc.) and sufficiently reduces the influence of external light to ensure visibility. can do.

  The preferred embodiment of the present invention has been described above with reference to the drawings, but the present invention is not limited to the above-described embodiment. That is, it is understood that other forms or various modifications that can be conceived by those skilled in the art within the scope of the invention described in the claims belong to the technical scope of the present invention.

3 HUD device 30 Case 31 Light irradiation part 32 Reflective member 33 Opening part 34 Combiner (translucent member)
40 Windshield (Translucent member)
41 Projection area 50 Virtual image 60 Diffusing member 70 Polarizing member EP Eye point (viewpoint)
100 Anisotropic optical film (anisotropic light diffusion layer)
400 Anisotropic optical film (anisotropic light diffusion layer)
L Display light M Outside light (sunlight)
P scattering central axis

Claims (8)

A display device that emits display light representing a display image toward a translucent member and displays the display image as a virtual image so as to be visible,
A light irradiation unit for irradiating the display light;
A reflective member that reflects the display light emitted from the light irradiator to the translucent member;
An anisotropic optical film comprising at least an anisotropic light diffusion layer having a matrix region and a plurality of columnar structures, wherein the anisotropic light diffusion layer has a linear transmittance changing according to an incident light angle of the display light or external light. When,
With
A display device in which the anisotropic optical film is provided on the reflecting surface side of the reflecting member.   The display device according to claim 1, wherein a diffusion member is provided on a side of the anisotropic optical film on which the display light or external light is incident. The maximum linear transmittance, which is the linear transmittance at an incident light angle at which the linear transmittance, which is the amount of transmitted light in the linear direction / the amount of incident light, reaches the maximum is 90% or more 90%. %, And
The minimum linear transmittance, which is the linear transmittance at an incident angle at which the linear transmittance is minimum, is 10% or less,
The display device according to claim 1, wherein the anisotropic light diffusing layer increases the diffuse transmittance of incident light as the linear transmittance decreases. The anisotropic light diffusion layer has one scattering center axis;
The anisotropic light diffusion layer increases the diffusibility with respect to the display light or external light incident in a predetermined angle range, shows a minimum linear transmittance, and is incident at an angle other than the predetermined angle range. The diffusibility decreases with respect to display light or external light, and the linear transmittance shows the maximum value,
The predetermined angle range is −20 ° to + 20 ° with reference to an incident light angle incident in the scattering central axis direction,
2. The display device according to claim 1, wherein the angle range other than the predetermined angle range is −30 ° to −60 ° or + 30 ° to + 60 ° with reference to an incident light angle incident in the scattering central axis direction.   The difference between the incident light angle at which the linear transmittance of the anisotropic light diffusion layer is minimum and the incident light angle at which the display light is incident on the anisotropic light diffusion layer or the regular reflection light angle with respect to the incident light angle is − The display device according to claim 1, wherein the display device is within a range of 20 ° to + 20 °.   2. The display according to claim 1, wherein the plurality of columnar structures are configured to be oriented from one surface to the other surface of the anisotropic light diffusion layer, and an aspect ratio between an average minor axis and an average major axis is less than 2. 3. apparatus.   The plurality of columnar structures are configured by being oriented from one surface of the anisotropic light diffusion layer to the other surface, and an aspect ratio between an average minor axis and an average major axis is 2 or more. The display device according to 1. The display device according to claim 1, wherein an anisotropic optical film is provided on the translucent member irradiated with the display light.

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