KR20010106393A - Backlight unit - Google Patents

Abstract

According to an embodiment of the present invention, a two-dimensional prism pattern is formed by crossing a first prism perpendicularly aligned with a lamp on a light guide plate and a second prism that is aligned parallel to the lamp and is aligned to be narrower as the distance away from the lamp. By using a light guide plate to deflect light from the liquid crystal panel side toward the liquid crystal panel side, it provides a backlight device that can reduce the number of components while maintaining high luminance of the light emitted from the backlight device and the entire liquid crystal panel evenly. Improve the productivity of the device.

Description

Backlight Unit

The present invention relates to a backlight device, and more particularly to a backlight device used as a surface light source of the liquid crystal display device.

In a liquid crystal display device mainly used in flat panel displays, the liquid crystal panel does not emit light by itself, but uses a liquid crystal for controlling light transmittance and needs a surface light source such as a backlight.

The backlight device places a line light source directly under the liquid crystal panel to directly illuminate the front of the liquid crystal panel, and a line light source is disposed on one side or a plurality of side surfaces of the liquid crystal panel to reflect and diffuse light beams on the light guide plate and the reflecting plate. In addition, devices such as notebook computers are mainly using edge type backlight devices.

However, since the edge type backlight device has lower luminance than the direct type backlight device, in order to compensate to this, a method of condensing light in the vertical direction using two prism sheets is used.

Hereinafter, a backlight device according to the related art will be described with reference to FIG. 4.

As shown in Fig. 4, the fluorescent lamp 1, which is a linear light source, and a lamp reflector 2 reflecting light from the fluorescent lamp 1, a light guide plate 3 for converting light from the fluorescent lamp 1 into a surface light source. ) Is disposed on one side of the light guide plate 3, and a reflecting plate 4 for preventing light leakage is disposed under the light guide plate 3. The upper part of the light guide plate 3 is provided with a diffuser plate 5 for uniformly diffusing light, and a prism in which triangular linear prisms 8 and 9 are successively formed to condense the diffused light thereon. The sheets 6 and 7 are arranged. The two prism sheets 6, 7 are arranged such that the linear prisms 8, 9 are perpendicular to each other to collect light in different directions.

In this configuration, the light from the fluorescent lamp 1 is incident on the light guide plate 3 and proceeds through the light guide plate, and part of the light is scattered by scattering patterns formed on the bottom surface of the light guide plate through multiple reflections. Some are moved to the reflector plate below the light guide plate. The light moved to the reflecting plate is reflected by the reflecting plate and directed again toward the upper part of the light guide plate having the liquid crystal panel. Therefore, the light passes through the diffuser plate and the light from the scattering pattern is uniformly diffused, and by using two prisms again, the light that is out of the direction perpendicular to the light guide plate is refracted in the direction perpendicular to the light guide plate and incident on the liquid crystal panel.

However, such a backlight device has a problem in that the production cost is high and the assembly process is complicated because productivity of the diffusion plate 5 and the two prism sheets 6 and 7 must be disposed on the light guide plate 3.

In order to overcome the above-mentioned problems, the present invention intersects the first prism perpendicularly aligned with the lamp on the upper surface of the light guide plate and the second prism parallel to the lamp and aligned so that the gap becomes narrower as the distance from the lamp increases. By using a light guide plate on which a two-dimensional prism pattern is formed, the light deviating from the third direction, which is toward the liquid crystal panel, is refracted in the third direction, so that the luminance of the light emitted from the backlight device is maintained high and evenly with respect to the entire liquid crystal panel. It is an object of the present invention to improve the productivity of the backlight device by providing a backlight device that can reduce.

1 shows a perspective view of a backlight device according to an embodiment of the invention;

2 shows a side view of the backlight device of FIG. 1 in accordance with an embodiment of the invention;

3 shows a top view of the backlight device of FIG. 1 according to an embodiment of the invention; And

4 shows a side view of a conventional backlight device.

<Description of Symbols for Main Parts of Drawings>

11: lamp 12: lamp reflector

13: light guide plate 14: reflecting plate

130: two dimensional prism pattern

131: first prism 132: second prism

133: scattering pattern 134: first region

135: second area

In order to achieve the above object, the present invention provides a backlight device that is used as a surface light source of the liquid crystal display device, the line light source for emitting light; Receives light from the light source from the side and guides it in a third direction toward the liquid crystal panel, and on the upper surface, first prisms perpendicular to the lamp and second prisms horizontal to the lamp cross each other at right angles to each other. A light guide plate on which a pattern (2nd dimensional prism pattern) is formed; And a reflector disposed under the light guide plate and reflecting light in a third direction opposite to the third direction from the light guide plate, wherein the two-dimensional prism pattern is formed as a first region and a second region prism pattern. Provided is a backlight device which is configured.

In addition, the first area prism patterns are continuously aligned adjacent to each other in the case of the first prisms perpendicular to the lamp, and the distance between the prism patterns becomes narrower as the distance from the lamp increases in the case of the second prisms parallel to the lamp. And the second region prism pattern is arranged to be adjacent to each other in succession such that the first prisms perpendicular to the lamp and the second prisms parallel to the lamp are aligned in succession. .

In addition, the present invention is characterized in that the scattering pattern for scattering light is formed on the lower surface of the light guide plate, and surrounds the light source and reflects the light of the light source and condenses the light guide plate through the opening to the light guide plate It provides a backlight device characterized in that it further comprises.

Finally, the present invention is a backlight device used as a surface light source of the liquid crystal display device, the line light source for emitting light; Receives light from the light source from the side and guides it in a third direction toward the liquid crystal panel. A two-dimensional prism pattern is formed on an upper surface, and the two-dimensional prism pattern is continuously aligned perpendicular to the lamp. A light guide plate parallel to the prisms and the lamp and having second prisms orthogonal to each other so that the distance between the prisms becomes narrower as the distance from the lamp increases; And a reflector disposed under the light guide plate and reflecting light in a third direction opposite to the third direction from the light guide plate.

Hereinafter, a backlight device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view schematically showing the structure of a backlight device according to an embodiment of the present invention, Figure 2 is a side view of the backlight device according to an embodiment of the present invention.

As shown in FIG. 1 and FIG. 2, in the backlight device according to the embodiment of the present invention, a lamp reflector 12 which surrounds a lamp 11 and a lamp 11 used as a line light source and has an opening on one surface thereof is an opening. It is disposed on one side of the light guide plate 13 through. The lamp 11 may use a fluorescent lamp such as a cold cathode ray tube or a hot cathode ray tube having high brightness while having low power consumption, and may be disposed on one side or both sides of the light guide plate 13. The lamp reflector 12 reflects the light from the lamp 11 and prevents light from leaking to portions other than the openings. In addition, the lamp reflector 12 collects light so that light can be emitted only through an opening formed in one surface, and the light is incident to the light guide plate 13 as a line light source through the opening.

The light guide plate 13 converts the light of the line light source emitted from the lamp 11 into a surface light source and is referred to as the liquid crystal panel side disposed above the light guide plate 13 in FIG. 2 (z-direction in FIG. 1, hereinafter referred to as 'third direction'). Has a function of inducing The lower surface of the light guide plate 13 may be formed obliquely, and may have a thinner thickness and a uniform thickness as it moves away from the opening of the lamp reflection plate 12. The light guide plate 13 may be made of a transparent polymer resin such as acryl, and a scattering pattern 133 formed through unevenness, etching, or printing may be formed on the bottom surface of the light guide plate 13 to scatter light to form a uniform surface light source. Formed. Instead of the scattering pattern, a resin having a scattering function may be used.

On the other hand, a reflector 14 is disposed below the scattering pattern 133 of the light guide plate 13 to reflect light emitted in a direction opposite to the third direction so that light does not leak. A two-dimensional prism pattern 130 is formed on the upper surface of the light guide plate 13 to condense light passing through the light guide plate 13 in a third direction. It will be described in more detail.

3 is a part of a plan view of a light guide plate according to an embodiment of the present invention.

1 and 3, the two-dimensional prism pattern 130 is formed on the upper surface of the light guide plate 13. The two-dimensional prism pattern has a triangular pillar shape and extends in a first direction (x-direction in FIG. 1) perpendicular to the lamp 11 and a second prism 131 parallel to the lamp 11. Second prisms 132 elongating in the direction (y-direction in FIG. 1) are formed orthogonal to each other. The first prism 131 refracts light having an inclination in the yz plane among the light incident on the light guide plate in the third direction, and the second prism 132 removes light having an inclination in the xz plane among the light incident on the light guide plate. It refracts in three directions and functions to enter the liquid crystal panel vertically.

The two-dimensional prism pattern is composed of the first region 134 and the second region 135 prism pattern according to the interval at which the first prism 132 is aligned. First, the first region 134 is an area adjacent to the lamp 11, and the prism patterns in the first region 134 are continuously aligned adjacent to each other in the case of the first prism 131, and the second prism ( In the case of 132, the distance between the prisms is aligned as the distance from the lamp 11 increases, that is, in the first direction. Therefore, in the first region where the intensity of light is high adjacent to the lamp 11, the number of the second prism 132 is smaller than that of the first prism, so that the slope of the light traveling in the first direction from the lamp has an inclination in the xz plane. It is possible to prevent the light from being refracted by the second prism. Therefore, in the light guide plate, the line light source can reach far away from the lamp to maintain uniform luminance throughout the light guide plate. In the first region, light having an inclination in the y-z plane is mainly refracted by the first prism in the third direction.

When away from the lamp 11 in the first direction, a second region 135 is shown in which the first prisms 131 are continuously aligned adjacent to each other, and the second prisms 132 are also continuously adjacently aligned. In the second region 135, a two-dimensional prism pattern 130 is formed in which the first prisms 131 and the second prisms 132 are continuously orthogonally adjacent to each other. Therefore, in the second region, as shown in the enlarged view of FIG. 1, the pyramidal square pyramid is inverted (that is, in the form of an inverted pyramid) and continuously formed. Due to the prism pattern of the second region 135, the light in the light guide plate, that is, incident by the lamp, scattered by the scattering pattern of the lower surface of the light guide plate, and reflected by the reflecting plate, is reflected by the first prism and the second prism. It is refracted in the third direction.

Accordingly, the first region 134 adjacent to the lamp 11 refracts light having a slope mainly in the yz plane, and the second region 135 far from the lamp 11 has a slope in the xz plane and the yz plane. All the light will be refracted. As a result, according to the present invention, light having a uniform luminance with respect to the entire light guide plate can be incident on the liquid crystal panel by using a light guide plate having a two-dimensional prism pattern that differs between the prism patterns of the first region and the second region.

It looks at the operation of the present invention according to the above configuration.

First, the light emitted from the lamp 11 is incident on the light guide plate 13 in the first direction together with the light reflected from the lamp reflector 12. The incident light passes through the first region 134 in which the two-dimensional prism pattern is formed, and since the second prism 132 is relatively less present in the first prism 131 in the first region 134, The light incident in the first direction does not concentrate refraction for light having an inclination in the xz plane due to the second prism 132, and only the refraction for light having an inclination in the yz plane by the first prism mainly occurs. . Therefore, the first direction, which is the main traveling direction of the incident light, undergoes a continuous reflection process with little interference, thereby allowing the light to reach far away from the lamp.

Since the first prism 131 and the second prism 132 are arranged at the same interval in the second region 135, both light having an inclination in the yz plane and light having an inclination in the xz plane are uniformly refracted. Face in three directions.

Meanwhile, some of the light incident into the light guide plate 13 toward the lower side of the light guide plate is scattered by the scattering pattern 133 formed on the bottom surface of the light guide plate 13, that is, the upper direction of the light guide plate with the liquid crystal panel, that is, in the third direction. The light passing through the lower surface of the light guide plate is reflected by the reflecting plate 14 disposed on the lower part of the light guide plate and incident on the light guide plate, thereby being uniformly distributed throughout the light guide plate.

The light incident on the light guide plate 13 is scattered by the scattering pattern 133, or is reflected by the reflecting plate 14 and proceeds toward the upper part of the light guide plate 13, that is, in the third direction. The light inclined in the direction and the longitudinal direction, that is, the light having the inclination in the yz plane and the light having the inclination in the xz plane pass through the two-dimensional prism patterns of the first region and the second region formed in the upper surface of the light guide plate, The light is refracted in the direction to be focused and then incident on the liquid crystal panel. Therefore, even a light guide plate having a two-dimensional prism pattern formed on the upper surface thereof can obtain a uniform and high luminance on the liquid crystal panel, and the manufacturing process of the backlight device can be simplified to increase productivity.

As described above, in the present invention, the first prism is continuously aligned, and the second prism has a two-dimensional prism pattern that becomes narrower as it moves away from the lamp. By refracting the out of light in the third direction, it is possible to implement a more uniform and high brightness to reduce the number of parts, to simplify the manufacturing process to improve productivity and to reduce the thickness of the backlight device. In addition, since the prism pattern is directly injection-molded on the upper surface of the light guide plate, the manufacturing process may be simplified and productivity may be increased.

Claims (6)

A backlight device used as a surface light source of a liquid crystal display device, A line light source that emits light; Receives light from the light source from the side and guides it in a third direction toward the liquid crystal panel, and on the upper surface, first prisms perpendicular to the lamp and second prisms horizontal to the lamp cross each other at right angles to each other. A light guide plate on which a pattern is formed; And a reflecting plate disposed under the light guide plate and reflecting light in a direction opposite to the third direction from the light guide plate in the third direction. And the two-dimensional prism pattern includes a first region and a second region prism pattern. The method of claim 1, The first area prism patterns are continuously aligned adjacent to each other in the case of the first prisms perpendicular to the lamp, and the distance between the prism patterns becomes narrower as the distance from the lamp increases in the case of the second prisms parallel to the lamp. Backlight device, characterized in that aligned. The method of claim 1, And wherein the second area prism pattern is aligned in succession adjacent to both first prisms perpendicular to the lamp and second prisms parallel to the lamp. The method of claim 1, A scattering pattern for scattering light is formed on the lower surface of the light guide plate. The method of claim 1, And a light source reflector that surrounds the line light source and reflects light of the line light source and condenses the light guide plate through an opening. A backlight device used as a surface light source of a liquid crystal display device, A line light source that emits light; Receives light from the light source from the side and guides it in a third direction toward the liquid crystal panel. A two-dimensional prism pattern is formed on an upper surface, and the two-dimensional prism pattern is continuously aligned perpendicular to the lamp. A light guide plate parallel to the prisms and the lamp and having second prisms orthogonal to each other so that the distance between the prisms becomes narrower as the distance from the lamp increases; And And a reflector disposed under the light guide plate and reflecting light in a direction opposite to the third direction from the light guide plate in the third direction.