JP3210380B2 - Injection molded edge light panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge light panel used for back lighting such as a liquid crystal backlight, and more particularly to an injection molded edge light panel formed by injection molding.

[0002]

2. Description of the Related Art An edge light panel of this type is provided with a light source of a cold cathode or hot cathode fluorescent lamp at an incident end face thereof to supply incident light from the incident end face, and is separated from the light source by a light guide pattern formed on the rear face. The light is guided in the direction, and the incident light is diffusely reflected on the front side to perform secondary surface illumination.

At this time, the light guide pattern is formed by performing screen printing on the back surface of a transparent resin substrate such as acrylic using an irregularly reflective ink.
Generally, a halftone dot pattern whose area is steplessly increased in the direction away from the incident end face side is used as the light guide pattern.

[0004]

However, the edge light panel formed by the screen printing has the following production problems caused by the transparent resin substrate or the screen printing. That is, since the transparent resin substrate is easily charged with static electricity, dust tends to adhere to the substrate including the production stage. Also, although the screen printing is performed in a considerably clean atmosphere, the dust still floats. Since it is difficult to completely prevent the dust, these dusts are often caught on the irregular reflection surface during screen printing, and the dusts appear as minute dots when the edge light panel is used. Light panels are treated as defective after completion.

[0005] Screen printing is also affected by ink composition, room temperature, humidity, squeegee pressure, and the like, and is liable to cause printing defects, for example, due to plate clogging. Non-defective products are likely to occur, so, for example, in order to prevent clogging of the above-mentioned plate, frequent plate washing must be performed for every few screen prints, and strict management is indispensable. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the problems associated with screen printing, to achieve high-precision, high-yield mass production, and high brightness. And to provide an injection molded edge light panel that ensures high uniformity.

[0007]

Means for Solving the Problems According to the present invention, according to the present invention, an edge light panel is formed by injection molding of a resin to simultaneously form a light guide pattern with minute projections arranged in a halftone dot pattern on the back surface. On the other hand, by forming the top surface of the minute projections in the light guide pattern as a textured surface roughened in a grain shape, the minute projections greatly promote non-directional irregular reflection of incident light. As a result, it has been found that it is possible to secure preferable light guide performance with high brightness and high uniformity. That is, the invention according to claim 1 is performed by injection molding a resin. An edge light panel having a screen-printable light guide pattern in which minute projections are arranged in a halftone dot pattern on the back surface,
An injection-molded edge light panel characterized in that the top surfaces of the minute projections in the light guide pattern are each formed as a textured surface roughened into a textured shape. 2. The injection-molded edge light according to claim 1, wherein the height of each of the minute projections is limited to 30 [mu] m or less so as to regulate the height of the minute projections to obtain a preferable form. Panel
According to a third aspect of the present invention, in addition to the above, each of the minute projections in the light guide pattern is formed so that the textured surface on the top surface of the minute projection can be formed easily and reliably. Then, the mold substrate is subjected to photoetching to form an inverted pattern of the light guide pattern by the photosensitive portion, and the inverted pattern is etched with an acid, an alkali, or the like, and the bottom is formed using a mold having a crimped bottom surface. The injection molding edge light panel according to claim 1 or 2, wherein each of the top surfaces is formed into a textured surface, and these are used as means for solving the above problems as the gist of the invention.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to the drawings showing the embodiments. A is an edge light panel. In this example, the edge light panel A is, for example, 7.7 cm × 1.
On the back surface of a transparent resin substrate B made of, for example, acrylic resin having a thickness of 2.5 cm and a thickness of 4 mm, the above-mentioned minute projections 10 are arranged in a halftone pattern so as to cover the entire surface except for the peripheral portion thereof. C is formed, and for example, a liquid crystal backlight of an in-vehicle liquid crystal display device is formed by a configuration similar to that of a conventional edge light panel of screen printing, and backlighting of the liquid crystal display surface is performed.

The fine projections 1 in the halftone dot arrangement in the light guide pattern C are cylindrical or raised with a small diameter, and in the present example, the fine projections 10 are formed into a cylindrical shape, and the protrusion height thereof is set. Of 30 μm or less, particularly 20 ± 5 μm, which is preferable for securing high brightness and high uniformity, is set to, for example, 20 μm, which is, for example, a halftone dot of an equally spaced matrix protrudingly arranged at the intersection of vertical and horizontal lines at 1 mm intervals. There is as a thing.

At this time, the fine projections 10 in the light guide pattern C have the same diameter as the above-mentioned equally spaced matrix from the respective primary light sources 20 provided on the incident end faces opposite to both sides of the edge light panel A toward the inside of the separation plane. It is assumed that the diameter is gradually increased steplessly while maintaining the positional relationship, and the diameter is changed so as to have a maximum diameter at the center, whereby the irregular reflection of each minute projection 10 is inversely proportional to the amount of incident light. This is controlled as follows.

The minute projections 10 in the light guide pattern C are:
Each of the top surfaces is a grained surface 11 which is roughened in a grain shape. The grain shape of the top surface is made by forming a light guide pattern C by photo-etching, laser processing or the like on a mold used for injection molding. It is formed by engraving and forming the bottom surface into a crimped shape, and then performing molding.

In this embodiment, the microprojections 10 are subjected to photo-etching on a mold substrate to form a reverse pattern of the light guide pattern C by a photosensitive portion thereof, and the reverse pattern is eaten by acid, alkali or the like. The top surface is formed as a textured surface 11 by shaping and using a mold whose bottom surface is formed in a textured shape.

The light guide pattern C is formed by using a screen-printable halftone pattern, that is, a halftone pattern film designed to obtain desired luminance and uniformity by screen printing on a transparent resin substrate. Perform the above photo-etching and increase the etching depth to 20μ.
m, and the crimped etching is performed in such a manner that wrinkles are formed on the bottom surface according to the processing time and the liquid amount.

As described above, in the edge light panel A having the light guide pattern C in which the minute projections 10 are arranged in a halftone dot shape, the minute projections 10 and the textured surface 11 thereof ensure a high light guide performance, and the brightness and the brightness are improved. In terms of uniformity, it reproducibly exhibits the same high performance as an edge light panel in which a light guide pattern is formed by screen printing. In addition, the edge light panel A is formed by forming a concave pattern such as a minute hole or a minute groove. Compared to the edge light panel obtained in this example, there is a tendency that fine extraordinary light emission due to the non-uniform shining portion is partially observed.
Had no abnormal light emission at all, and was particularly excellent in uniformity.

Although the illustrated example is as described above, in the present invention, the fine projections are appropriately polygonal cylindrical in addition to the above-mentioned cylinders, and have a protruding shape having a trapezoidal cross section. In the case of a one-sided light source in which a light source is arranged on one side of the incident end face, the diameter change of the above minute projection is made to gradually increase toward the opposite end face, and the luminance is affected by the reflected light of the opposite end face. The light guide pattern is designed to absorb the non-uniformity of the brightness by changing the diameter as needed, such that the light guide pattern gradually decreases in the vicinity of the facing end face where the light guide rises. If the pattern conforms to the halftone dot pattern that can be used, the arrangement of the fine projections should be different from that of the above-mentioned equispaced matrix and be staggered at an angle. The density of projections is general However, if necessary, the density can be reduced to about 60 to 70 lines, for example, to reduce the prominence of the fine protrusions. The edge light panel, its light guide pattern, minute projections, embossed surface, mold, etc., each with a specific shape, structure,
The material, the method of producing the material, and the like can be of various forms without departing from the gist of the invention.

[0016]

Since the present invention is configured as described above, the invention according to claim 1 solves the problems associated with screen printing, enables high-precision mass production with high precision, and Provided is an injection-molded edge light panel that has a textured surface roughened in a textured shape, greatly promotes non-directional irregular reflection of incident light, and ensures high brightness and high uniformity light guiding performance. In addition to the above, the invention according to claim 2 can restrict the height of the microprojections to have a preferable form, and the invention according to claim 3 is also similar to the above. In addition to the above, it is possible to easily and reliably form the crimped surface on the top surface of the fine projection.

[Brief description of the drawings]

FIG. 1 is a rear view showing a relationship between an edge light panel and a primary light source.

FIG. 2 is a partially enlarged view of a light guide pattern.

FIG. 3 is an enlarged perspective view showing a minute projection.

FIG. 4 is a partially enlarged sectional view of the edge light panel.

FIG. 5 is a rear view of the edge light panel taken with a colored rear surface.

[Explanation of symbols]

 Reference Signs List A edge light panel B transparent resin substrate C light guide pattern 10 minute protrusion 11 textured surface 20 primary light source

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B 5/02

Claims (3)

(57) [Claims] 1. An edge light panel on which a screen-printable light guide pattern in which fine protrusions are arranged in a halftone dot pattern on a back surface by injection molding a resin, wherein a top surface of the fine protrusions in the light guide pattern is provided. Characterized in that each of them has a textured surface which is roughened into a textured shape. 2. The injection-molded edge light panel according to claim 1, wherein the height of each of the minute projections is 30 μm or less. 3. The method according to claim 1, wherein each of the minute projections in the light guide pattern is
Photo-etching is performed on the mold substrate to form an inverted pattern of the light guide pattern by the photosensitive portion, and the inverted pattern is etched with an acid, an alkali, or the like, and the bottom is formed using a mold having a crimped bottom surface. 2. The method according to claim 1, wherein each of the top surfaces is a textured surface.
Or the injection-molded edge light panel according to 2.