KR100646137B1 - Light guide plate for backlight unit - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate comprising a surface light source backlight unit having an edge light emitting side light emitting means. Particularly, a pattern comprising rectangular grooves engraved with a laser in order to obtain uniform brightness over the entire light guide plate. In addition to the main pattern portion throughout the light guide plate to improve the formation method, the light is irradiated relatively less from the light emitting means, so that the dark portion is formed, and the edge or the corner of the side orthogonal to the side of the light guide plate body with light emitting means A light guide plate for a backlight unit for a liquid crystal display device in which an auxiliary pattern portion is formed.

The light guide plate according to the present invention comprises: a main pattern portion including a plurality of dotted lines formed of a plurality of rectangular grooves engraved with a laser arranged in parallel with the light emitting means; And a plurality of grooves formed at edges or corners of the sides orthogonal to the sides of the light guide plate body provided with the light emitting means, and arranged in a shape to widen the entire formation area of the grooves forming the main pattern portion. It has an auxiliary pattern part.

Backlight, surface light source, light guide plate, laser processing, edge light, pattern, main pattern part, auxiliary pattern part, rectangular groove, groove

Description

Light guide plate for backlight unit {LIGHT GUIDE PLATE FOR BACKLIGHT UNIT}             

Figure 1a is a schematic exploded perspective view showing an example of a conventional backlight unit,

1B is a schematic cross-sectional view of a light guide plate of a conventional backlight unit;

2, 3A, 3B, 3C, 3D and 3E are partial schematic views of a light guide plate showing various shapes of rectangular grooves of an auxiliary pattern portion constituting the light guide plate according to the present invention;

4 is a schematic view showing various forms of the auxiliary pattern portion of the light guide plate according to the present invention.

<Description of the symbols for the main parts of the drawings>

10, 11, 13, 15, 17, 110: Light guide plate 120: Reflector

130: diffusion plate L: light emitting means

111, G, Gm1, Gs1, Gm2, Gs2, Gs3, Gs4, Gs5: Groove

S, S1, S2, S3, S4, S5, S6, S6, S7, S8: Auxiliary pattern part

M, M1, M2: main pattern part

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate comprising a surface light source backlight unit having an edge light emitting side light emitting means. Particularly, a pattern comprising rectangular grooves engraved with a laser in order to obtain uniform brightness over the entire light guide plate. In addition to the main pattern portion throughout the light guide plate to improve the formation method, the light is irradiated relatively less from the light emitting means, so that the dark portion is formed, and the edge or the corner of the side orthogonal to the side of the light guide plate body with light emitting means The light guide plate for a backlight unit used for the liquid crystal display device which formed the auxiliary pattern part of this invention is related.

In general, a light-receiving flat panel display such as an LCD or a light box, etc., injects a liquid crystal having an intermediate property between a solid and a liquid between two thin glass plates to change the arrangement of liquid crystal molecules upon power supply. This is a display that displays the image by generating the contrast, and unlike PDP, FED, and organic ELD, it is a non-light-emitting type (light-receiving element). It requires a backlight unit in the form of a surface light source that can be maintained.

A key component of the general backlight unit (U) shown schematically in FIG. 1A is light emitting means for determining luminance and chromaticity, such as a cold cathode fluorescent lamp (CCFL) or an LED. (L), the reflector 120 for increasing the efficiency of the light generated by the light emitting means (L), and the linear light received from the reflector 120 to form a surface light source on the entire image display surface of the PMMA resin system It is a light guide plate 110 (LGP; Light Guide Plate) processed with a specially designed dot pattern on the back surface of the transparent acrylic plate. In addition, in the surface light source formed by the three major elements CCFL, Reflector, and LGP, light is efficiently focused and diffused by the diffusion plate 130 provided on the light guide plate. In addition, an upper surface of the diffusion plate 130 may be provided with a separate prism plate to increase the light collecting efficiency.

The method of forming a dot pattern on the light guide plate is a method of forming ink into a predetermined pattern by a printing method, a method of melting the light guide plate raw material resin and injecting it into a mold having a predetermined pattern, and forming a pattern using a laser. And so on.

The backlight unit U shown in FIG. 1A has a laser-guided light guide plate 110, and in particular, according to the arrangement of the light emitting means L, the number of parts such as an edge light type, among them, one-chip reduction, thinning, and high efficiency are increased. It is constructed in a side emitting type suitable for At least one light emitting means may be arranged on the light guide plate, and two light emitting means are generally provided symmetrically.

In the conventional surface light source backlight unit, the light emitted from the light emitting means is irradiated to the light guide plate, and the light irradiated from the light guide plate is reflected to the diffuser plate with uniform illuminance at each part by the reflector, and is diffused to the front through the diffuser plate. .

As shown in FIGS. 1A and 1B, in the manufacturing method of a light guide plate using a laser processing method, a shape of a pattern is formed by a combination of bar-type grooves in order to maximize processing efficiency and obtain uniform luminance of a laser device. It is produced by forming a plurality of dotted lines in parallel.

The prior art related to the light guide plate manufactured by the conventional laser processing method is that the light guide pattern is arranged by varying the intermittent straight grooves by laser processing to diffuse and scatter light of uniform illuminance. Korean Patent Laid-Open Publication No. 2002-0064227 (2002.08.07) related to the formed light guide plate, `` a surface light source device having a light guide plate having an intermittent pattern '' and a semicircular intaglio pattern are formed on the light guide plate as a light reflection structure, and the light of the intaglio pattern is Korean Patent Registration No. 0358847 (2002.10.16) related to the light guide plate having scattering irregularities for irregular surface roughness on the inner surface of the reflective structure includes a light guide plate having a light reflection structure of an intaglio pattern.

The above techniques have been filed by the applicant of the present invention, and in order to solve the difference in the light guide amount far and near from the light emitting means, the length of the rectangular groove engraved in the light guide plate, and the spacing between the dotted grooves composed of a plurality of grooves ( pitch) and adjusting the spacing between adjacent dashed lines.

Due to the characteristics of the light emitting means installed on the side of the light guide plate, in particular, the cold cathode fluorescent lamp, a dark portion due to low luminance is generated at a portion where both ends of the cold cathode fluorescent lamp are in contact with each other by the relatively low light emission in the vicinity of the electrode. There was a problem.

In addition, the light emitting means provided in the conventional light guide plate is generally installed only on one side of the light guide plate, in particular, the long side of the light guide plate in order to lower the manufacturing cost of the product. Iii) also has the problem that dark areas occur.

The presence of this dark part and the neighboring rosters which appear relatively bright by this dark part impairs the appearance of the product and causes problems in luminance uniformity.

The prior art does not provide a more complete solution to this problem.

The present invention is a light guide plate of the conventional backlight unit as described above orthogonal to the side of the light guide plate main body provided with light emitting means, generally the edge or corner of the short side light due to the nature of the installation form of the light emitting means This has been proposed to solve the problem of less irradiated and dark.

Accordingly, the present invention provides a light guide plate having a separate auxiliary pattern portion for widening the formation area of the rectangular groove forming the main pattern portion on the edge or corner of the short side where no light emitting means is provided in addition to the main pattern portion formed over the light guide plate. It aims to do it.

In another aspect, the present invention provides a light guide plate having an optimal pattern by varying the dimensions, arrangement intervals, arrangement of the dotted lines forming the auxiliary pattern portion and / or the main pattern portion, or a plurality of rectangular grooves forming the dotted line. For the purpose of                         

As a result, an object of the present invention is to remove uneven appearance of the light guide plate, that is, the backlight unit due to the generation of the light and dark portions, through the combination of the various main pattern parts and the auxiliary pattern parts, and to obtain uniform luminance throughout the backlight unit.

In order to achieve the above object, a light guide plate for a backlight unit according to the present invention includes: a main pattern part including a plurality of dotted lines made of a plurality of engraved rectangular grooves arranged in parallel with the light emitting means; And a plurality of grooves formed at edges or corners of the sides orthogonal to the sides of the light guide plate body provided with the light emitting means, and arranged in a shape to widen the entire formation area of the grooves forming the main pattern portion. It has an auxiliary pattern part.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote members having the same function. In FIG. 2 and below, the portion indicated by the dashed-dotted line indicates the auxiliary pattern portion region S. As shown in FIG.

First, referring to FIG. 2, the light emitting means L is provided at both sides of the light guide plate 10, that is, at two long sides. However, the light emitting means may be provided only on one side of the long side. The light emitting means may be a fluorescent lamp or an LED.

The bar type grooves Gm constituting the main pattern portion M formed in the light guide plate 10 are formed by a laser beam, have the same length and width, have the same spacing between the grooves, and the grooves. The spacing between the dashed lines that form the same is also the same. The direction of formation of the dotted line constituting the main pattern portion M is parallel to the long side, that is, the light emitting means.

However, the shape of the main pattern portion may be variously modified in a manner that varies the length of the rectangular grooves, the pitch between the rectangular grooves in the same dotted line, and the intervals between the dotted lines regularly or irregularly. In particular, the modified form of the main pattern portion is preferably a form in which a dark portion can be formed due to the characteristics of the light emitting means, so as to obtain a uniform brightness by enhancing the brightness of a part far from the light emitting means.

The main pattern portion for this purpose may be made in such a way as to increase the overall forming area of the rectangular grooves in the portion where the arm portion can be formed.

When the wavelength of the laser beam irradiated to the light guide plate, the cross-sectional area of the irradiated light, and the irradiation time of the beam per unit area of the rectangular groove for pattern formation are the same throughout the manufacturing process, the widths of the rectangular grooves formed in the light guide plate are the same (these The method may also be suitable for mass production systems), and the method of increasing the total area of the rectangular grooves may include, for example, increasing the length of the grooves of the rectangular grooves, shortening the space between the grooves, or collecting the rectangular grooves. The interval between each dotted line may be shortened.

Next, in FIG. 2, the portion S of which the auxiliary pattern part forming the core of the present invention is formed is a side that is perpendicular to the side of the main body of the light guide plate 10 provided with the light emitting means L, that is, the short side. ) Edge area. The groove Gs constituting the auxiliary pattern portion S is a solid line or a dotted line orthogonal to the groove constituting the main pattern portion M. FIG. The interval between the solid line and the dotted line may be equal to or closer to the edge portion of the short side.

The shape of the auxiliary pattern portion S is also arranged in such a manner as to broaden the overall formation area of the rectangular grooves forming the main pattern portion.

Therefore, the shape of the auxiliary pattern portion of FIG. 2 may be variously modified within the range of achieving the object of increasing the overall formation area of the rectangular groove.

Forming the main pattern portion using the laser beam on the surface of the light guide plate is synchronized with the optical driving portion including a mirror portion driven by the step motor according to the coordinate value of the pattern and the predetermined pattern portion forming region through the control unit of the laser generation system. The laser beam outputted from the laser driver by the pulse signal is transmitted to the optical driver, and the laser beam is finally scanned on the light guide plate by the mirror part positioned at the end of the optical driver.

At this time, since the laser device recognizes the starting point and end point of the light guide pattern portion with respect to the origin coordinate, and the position coordinate values for the shape therebetween, the time required for data processing is shorter than that of the curve. Since the linear drive is the fastest as the drive method by the movement method, the shape of the pattern portion is most preferably an intermittent rectangular groove.

On the other hand, the laser beam is a laser beam having a long wavelength of 1 micrometer or more, preferably 10.6 micrometers or more in the infrared region capable of heat absorption of the transparent acrylic resin, which is a material of the light guide plate. In the formation of the light guide pattern portion by the laser beam, it is preferable to scan the laser beam in order to prevent the light guide plate from being locally heated.

In order to reduce the local heating of the light guide plate by the laser beam, increasing the moving speed of the mirror part lowers the energy density of the laser beam, thereby increasing the output of the laser beam to compensate for this.

After the main pattern part is completed as described above, the auxiliary pattern part may transfer the processed file to the ray device by using a separate file in addition to the light guide plate on which the main pattern part is formed, but overlap the main pattern part and the auxiliary pattern part. It is also possible to process the whole pattern after drawing the entire pattern. At this time, it is determined whether to process at one time or divided into two in consideration of the workability according to the processing amount of the auxiliary pattern portion.

When the desired auxiliary pattern portion is formed to be orthogonal to the rectangular groove longitudinal direction of the main pattern, it is preferable to proceed by dividing into two. In this case, it is preferable to insert the light guide plate in a direction rotated by 90 degrees for the productivity of the light guide plate for the auxiliary pattern processing.

Next, FIG. 3A illustrates a light guide plate 11 having a main pattern portion M1 and an auxiliary pattern portion S1 different from those of FIG. 2.

The distance between the dotted lines formed by collecting the rectangular grooves Gm1 constituting the main pattern portion M1 is narrower as the distance from the light emitting means L increases. Further, the distance between the rectangular grooves Gm1 in the same dotted line is also formed narrower as it moves away from the light emitting means L. As described above, all of them have a shape that increases the area formed by the rectangular grooves as the distance from the light emitting means L increases. Through this, it is expected that the brightness of a part far from the light emitting means L can be increased.

In addition, the auxiliary pattern portion S1 is formed at a corner portion of the light guide plate 11 having a relatively low luminance. The rectangular groove Gs1 constituting the auxiliary pattern portion S1 is formed between the dotted lines constituting the main pattern portion M1, and the rectangular groove Gs1 forms a solid line and is parallel to each other. However, the rectangular groove forming the auxiliary pattern portion may form a dotted line.

As shown in FIG. 2, the auxiliary pattern portion S1 is arranged in such a manner as to widen the entire formation area of the rectangular grooves Gm1 constituting the main pattern portion M1.

In addition, the shape of the auxiliary pattern portion S1 is a right triangle. This increases the overall forming area of the rectangular groove in both the portion away from the light emitting means L of the light guide plate on which the dark portion may be formed, the corner portion, and the short edge portion where the light emitting means L is not disposed. It is a very preferable form.

Although the lengths and spacings of the rectangular grooves Gm1 and Gs1 constituting the pattern portions M1 and S1 are different from each other in FIG. 3A, the widths of the grooves are the same for mass productivity.

Subsequently, in the light guide plate 15 illustrated in FIG. 3B, the auxiliary pattern part S2 forms a right triangle like the one in FIG. 3A. However, the spacing between the dotted lines forming the main pattern portion M2 is the same as a whole, and the distance between the grooves and the length of the rectangular grooves Gm2 constituting the dotted lines is also the same.

The rectangular grooves Gs2 constituting the auxiliary pattern part S2 are arranged on the same virtual straight line as the dotted lines constituting the main pattern part M2, and each rectangle constitutes a dotted line of the main pattern part M2. The length is longer than the groove Gm2.

In FIG. 3C, the shape of the main pattern portion M2 and the rectangular groove Gm2 of the light guide plate 15 is the same as that of FIG. 3B 13, and the shape formed by the auxiliary pattern portion S3 is also a right triangle.

However, unlike FIG. 3B, the rectangular grooves Gs3 constituting the auxiliary pattern part S3 are arranged on the same virtual straight line as the dotted lines constituting the main pattern part M2 and each dotted line of the main pattern part M2. It has the same length as the rectangular groove (Gm2) constituting the interval, the interval between the rectangular grooves (Gs3) forming a dotted line of the auxiliary pattern portion (S3) is a dotted line of the main pattern portion (M2) of the same virtual straight line. Shorter than the gap between the rectangular grooves Gm2.

Next, the light guide plate 17 illustrated in FIG. 3D has the same shape as that of FIG. 3B, the main pattern portion M2, and the rectangular groove Gm2, and the shape formed by the auxiliary pattern portion S4 is also a right triangle. to be.

However, the rectangular grooves Gs4 constituting the auxiliary pattern portion S4 are arranged in a form orthogonal to the rectangular grooves Gm2 of the dotted lines constituting the main pattern portion M2. The rectangular groove forming the auxiliary pattern portion S4 may form a solid line.

If necessary, each of the obtuse grooves may not be orthogonal but may meet in an acute angle. The form of the engagement can also change irregularly.

In addition, although not illustrated as shown in FIG. 3E, the groove Gs5 constituting the auxiliary pattern part S5 may have a dot shape formed between the dotted lines constituting the main pattern part.

In addition, the deformation | transformation form of a main pattern part and an auxiliary pattern part can be many combinations.

Such modifications are limited by the idea of the present invention that the overall formation area of the rectangular grooves should be increased in the corner portion of the light guide plate, the edge of the side where the light emitting means is not provided, and the portion away from the light emitting means.

Next, in FIG. 4, the distribution patterns of the auxiliary pattern parts formed at the corners are (A) right triangles S6, (B) arcs S7, and (C) rectangles S8. Moreover, it is also possible to be any combination of these distribution forms.

When the backlight unit is configured using the light guide plate according to the present invention described above, light incident to the light guide plate side as the light emitting means emits light guides the light guide plate made of acryl, which is irradiated to the lower part of the light guide plate. Is scattered and diffused by the main pattern portion, the auxiliary pattern portion, and the reflector of the present invention and is irradiated to the front surface of the light guide plate.

In the light guide plate according to the present invention, scattering and diffusion of light by the main pattern portion and the auxiliary pattern portion are reflected to the front surface by a boundary surface of a rectangular groove formed of a straight line or an interruption line. At this time, since the light emitted from the light emitting means does not reach sufficiently or sudden bending occurs, the appearance stains caused by the edge of the light guide plate, the edge of the side where the light emitting means is not disposed, and the dark part that may be generated from the light emitting means The amount of light is sufficiently compensated by the auxiliary pattern portion, so that uniform luminance can be obtained over the entire light guide plate.

As described above, the light guide plate having the intaglio pattern for uniform luminance according to the present invention has a rectangular groove forming area of the main pattern portion at the edge or corner of the short side where no light emitting means is installed in addition to the main pattern portion formed over the light guide plate. By forming a separate auxiliary pattern portion to make a wider than can make the overall brightness of the light guide plate uniform.

As a result, the present invention aims to remove uneven appearance of the light guide plate, that is, the backlight unit due to the generation of the light and dark portions, through the combination of the various main pattern parts and the auxiliary pattern parts, and to obtain uniform luminance throughout the backlight unit.

In the light guide plate according to the present invention, the dark portion may be completely removed to remove a defect rate of 95% or more due to the dark portion. In addition, when the auxiliary pattern part is formed at the edge of the side where the light emitting means is not provided, the luminance uniformity can be improved by 3% or more, and thus the luminance uniformity defective rate can be eliminated close to 100%. In addition, the luminance of the corners of the light guide plate was improved by more than 13% by the auxiliary pattern.

In the above description of the present invention, the light guide plate having a specific pattern shape and structure has been described with reference to the accompanying drawings. However, the present invention can be variously modified and changed by those skilled in the art. In the case of the idea of the present invention to increase the overall formation area of the rectangular groove in the portion should be interpreted as belonging to the protection scope of the present invention.

Claims (14)

A main pattern portion having a plurality of dotted lines formed of a plurality of rectangular grooves engraved by a laser arranged in parallel with the light emitting means; And A plurality of rectangular grooves engraved by the laser on the edge of one side of the light guide plate without the light emitting means orthogonal to the same virtual straight line as the dotted lines forming the main pattern portion at a position corresponding to the light emitting portion of the light emitting means. It is arranged in the form, having the same length as the rectangular groove of the main pattern portion, the interval between the rectangular grooves forming a dotted line of the auxiliary pattern portion is a backlight, characterized in that shorter than the interval between the rectangular grooves forming a dotted line of the main pattern portion Light guide plate for the unit. delete delete delete delete delete delete delete delete delete delete delete delete delete

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