JP2002116307A - Field angle control optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a field angle control optical member which has small light loss and superior light-beam use efficiency. SOLUTION: This field angle control optical member is characterized in that multiple cylindrical lenses are provided side by side on an incidence side so as to guide projection light from behind to a light projection side and at least one striped light shield layer is provided at a part that the projection light does not pass through in parallel to a light-projection-side flat surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical member arranged on the front of various display devices such as a liquid crystal display device and capable of controlling a viewing angle.

[0002]

2. Description of the Related Art Signboards, various types of lighting, and backlights for liquid crystal display devices are widely used. In general, a planar light source does not have directivity because the luminance of the light emitting surface is made uniform by using a diffusion plate. However, depending on the planar light source, it may be required to narrow the light emission direction to a narrow range. In response to such demands,
A “louver sheet” including a row of light-shielding plates for adjusting a viewing angle, which includes a plurality of light-shielding plates between a plurality of transparent substrates, is known. FIG. 4 is a schematic diagram showing the configuration of the light shielding plate row.
In this configuration, the light shielding plates are arranged at intervals d. In the figure,
The viewing angle θ is θ = arctan (d / h). Here, h is the width of the light shielding plate. Shield plate spacing d, Shield plate width h
, The viewing angle θ can be controlled. By the way, the conventional “louver sheet” including a row of light-shielding plates for adjusting the viewing angle has a problem that the light-shielding plate blocks a part of the straight light, and the light illuminance greatly fluctuates simultaneously with the control of the viewing angle. Was.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a viewing angle controlling optical member having a small light loss and excellent light use efficiency.

[0004]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of cylindrical lenses are juxtaposed on a light incident side so as to guide projection light from behind to a light emitting side. A viewing angle controlling optical member, wherein at least one stripe-shaped light-shielding layer is provided in a portion through which the projection light does not pass, in parallel with the flat surface on the light emission side.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIG. 1 is a schematic sectional view showing a first embodiment of the present invention. FIG.
FIG. 4 is a schematic sectional view showing a second embodiment of the present invention. FIG.
As shown in FIG. 1, as a first embodiment, the viewing angle controlling optical member 10 of the present invention includes a plurality of cylindrical lenses 11 on the light incident side so as to guide the projection light from behind to the light emitting side. In this configuration, two light-shielding layers 12-1 and 12-2 are provided in a portion where the projection light does not pass in parallel with the light-incident-side lens portion arranged in parallel and the flat surface of the transparent substrate 13 on the light-emitting side. . As shown in FIG. 2, as a second embodiment, the viewing angle controlling optical member 20 of the present invention includes a plurality of cylindrical lenses 21 on the light incident side so as to guide the projection light from behind to the light emitting side. A light-incident-side lens portion arranged side by side on the base member 23;
The configuration in which one light shielding layer 22 is provided in parallel with the flat surface of the transparent substrate 23 on the light emission side is shown. Viewing angle control optical member of the present invention is not limited to the above configuration, the light shielding layer,
Two or more of them may be provided.

As the material of the transparent substrate used in the viewing angle controlling optical member of the present invention, a plastic film or sheet is preferably used, but is not particularly limited.

[0007] The cylindrical lens of the viewing angle controlling optical member of the present invention is a group of convex lenses formed on the transparent substrate, and the lens pitch is preferably 0.5 mm or less, and the lens radius is preferably 0.5 mm or less.

The light-shielding layer of the viewing angle controlling optical member of the present invention is
The width is several tens of percent of the lens pitch and the thickness is 5 μm
The following is desirable.

FIG. 3 is an explanatory view for explaining a method of manufacturing the viewing angle controlling optical member of the present invention in the first embodiment. The manufacturing method will be described with reference to FIG.
First, the light shielding layer 32 is provided on each of the transparent bases 33-1 and 33-2.
-1, 32-2 are formed by various printing methods, coating methods, transfer methods and the like. Next, the transparent base materials 33-1 and 33-2 on which the light shielding layers are formed are coated with an ultraviolet curing agent,
The light-shielding layer 32-
Bonding is performed so that the positions of 1, 32-2 are matched. When three or more light-shielding layers are provided, the layers may be sequentially laminated in the same manner.

Here, as the transparent bases 33-1 and 33-2, a sheet of a transparent resin such as an acrylic resin, a polycarbonate resin, a vinyl chloride resin, and a polyethylene terephthalate resin can be used. The adhesive layer 34
For example, a transparent adhesive such as acrylic or polyester or an ultraviolet curable resin such as urethane acrylate can be used. In order to form the light-shielding layers 32-1 and 32-2, carbon black or a dye that absorbs light,
It is sufficient that the ink is transferred only to the portion having the width by the gravure printing method using the ink in which the pigment is dispersed.

Further, on the light incident surface of the transparent substrate 33-2 closest to the light incident side, a light incident side lens portion composed of the cylindrical lens 31 is formed. For this, using a mold having the reverse shape of the cylindrical lens 31, the mold is placed on the transparent sheet 33-2, and a liquid of a polymerizable resin is filled between the mold and the transparent sheet. , And may be polymerized and cured. Further, an ultraviolet curing resin or an electron beam curing resin is applied on a molding die, a transparent sheet 33-2 is laminated thereon, and the resin is cured by irradiating an ultraviolet ray or an electron beam. I just need. At this time, the position of the mold and the position of the light shielding layer 32-2 are matched.

Next, an example of a preferred method of manufacturing the viewing angle controlling optical member of the present invention provided with one light shielding layer shown in the second embodiment will be described with reference to FIG. An ultraviolet-curable resin layer (not shown) is formed on the flat surface of the substrate opposite to the surface of the cylindrical lens 21. While relatively moving a belt-like light beam (not shown) in the direction in which the cylindrical lenses 21 are arranged, the cylindrical lens 2
1, a belt-like light beam extending in the longitudinal direction is perpendicularly irradiated from the cylindrical lens 21 side to the ultraviolet curable resin layer formed on the flat surface of the base material, and a portion of the light beam condensed by each cylindrical lens 21 is irradiated. After curing the ultraviolet curable resin, a transfer sheet (not shown) in which a black colored layer is formed on a transfer sheet substrate is superimposed on the entire surface of the ultraviolet curable resin layer on the colored layer side, and light shielding is performed. Utilizing the adhesiveness of the resin in the uncured portion corresponding to the layer 22, the colored layer is adhered only to the uncured portion corresponding to the light-shielding layer 22 to form a stripe-shaped light-shielding layer. Alternatively, the black fine powder toner can be selectively adhered only to the uncured portion.

According to the above-described exposure process, each cylindrical lens functions in the same way as collective irradiation of parallel light from the cylindrical lens side to the entire surface. The light-shielding layer to be formed is for a non-light-collecting portion due to irradiation of the actual lenticular sheet with ultraviolet rays, and is located at a position where the light-shielding layer must be formed, that is, at a region where the projection light does not pass. Can be formed with precision. Further, according to the above exposure process, the width of the light-shielding layer can be controlled by controlling the width of the adhesive portion according to the amount of exposure. The width of the light-shielding layer is defined as the ratio of the width of the non-light-collecting portion to the width of the (non-light-collecting portion + light-collecting portion), and the BS ratio can be easily controlled.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. The present invention is not limited to the following examples.

Example 1 A viewing angle controlling optical member having the following structure and provided with two light shielding layers shown in FIG. 1 was prepared. Cylindrical lens pitch p = 0.2196 mm Cylindrical lens radius of curvature r = 0.32 mm Lens sheet thickness t = 0.9 mm Refractive index of lens sheet base n = 1.5 Shielding layer width h1 = 0.033 mm (BS ratio 30%) ) Light-shielding layer thickness w1 = 0.002 mm Light-shielding layer width h2 = 0.077 mm (BS ratio 70%) Light-shielding layer thickness w2 = 0.002 mm The first light-shielding layer (h1, w
The base material provided with 1) and the base material provided with the second light-shielding layer (h2, w2) are laminated via an adhesive layer, and a light-entering lens portion is formed using a mold having a convex lens shape. Then, the entire thickness was set to (lens sheet thickness t) 0.9 mm. The viewing angle θ of the obtained viewing angle control optical member is 55.
Degree. The viewing angle θ can be controlled by controlling the relationship between the thickness of the substrate provided with the first light-shielding layer and the thickness of the substrate provided with the second light-shielding layer, and the width and thickness of each light-shielding layer. is there.

Embodiment 2 A viewing angle controlling optical member having the following structure and provided with one light shielding layer shown in FIG. 2 was prepared. Cylindrical lens pitch p = 0.2196 mm Cylindrical lens radius of curvature r = 0.32 mm Lens sheet thickness t = 0.9 mm Refractive index of lens sheet base n = 1.5 Light shielding layer width h1 = 0.077 mm (BS ratio 70%) ) Thickness of light-shielding layer w1 = 0.002 mm In addition, a cylindrical lens was previously formed on the transparent substrate of the light-entering lens portion using a mold having a convex lens shape. The light-shielding layer was formed by an exposure method utilizing the condensing property of a cylindrical lens, utilizing the non-adhesive and adhesive properties of the exposed and unexposed portions of the ultraviolet curable resin layer provided on the flat surface of the transparent substrate. The viewing angle θ of the obtained viewing angle controlling optical member was 80 degrees.

[0017]

According to the present invention, the viewing angle can be arbitrarily controlled, and the light illuminance does not fluctuate greatly with it.
It is possible to provide a viewing angle controlling optical member having a small light loss and excellent light use efficiency. It is suitably used for various display devices such as a liquid crystal display device.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of a viewing angle control optical member as a first embodiment of the present invention.

FIG. FIG. 9 is a schematic cross-sectional view showing a configuration of a viewing angle control optical member as a second embodiment of the present invention.

FIG. 3 is an explanatory view showing a method for manufacturing the viewing angle controlling optical member of the present invention in the first embodiment.

FIG. 4 is an explanatory view showing a conventional viewing angle control optical member.

[Explanation of symbols]

10, 20, 30, 40 ... viewing angle control optical member 11, 21, 31 ... light entrance side lens unit (cylindrical lens) 12-1, 12-2, 22 ... light shielding layer 13, 23, 33-1 .., 33-2, 43... Transparent substrate 34... Adhesive layer p... Cylindrical lens pitch t... Viewing angle controlling optical member thickness θ... Viewing angle h1, h2. Light shielding layer thickness

Claims (1)

[Claims] 1. A plurality of cylindrical lenses are arranged side by side on a light incident side so as to guide projection light from behind to a light emitting side.
A viewing angle control optical member, wherein at least one stripe-shaped light-shielding layer is provided in a portion through which the projection light does not pass, in parallel with the flat surface on the light emission side.