KR20080004139A - A light guided panel and backlight unit having the same - Google Patents

Abstract

A light guide panel of a backlight unit and a backlight unit having the same are provided to increase a central luminance and accomplish uniformity by narrowing a reflection angle and maximizing reflection characteristics. A light guide panel(100) has a reflective surface(102) with an intaligo pattern formed such that a plurality of first V-shaped grooves(110) extend in the first direction and a plurality of second V-shaped grooves(120) extend in the second direction. The first and second V-shaped grooves(110,120) cross each other, and the depth of the first V-shaped grooves(110) is lower than the second V-shaped grooves(120). A plurality of third V-shaped grooves(130) formed on a light output surface(101) of the light guide panel(100) and extend in the third direction. The first V-shaped grooves(110) has a depth of 1/2 or 1/4 of the depth of the second V-shaped grooves(120).

Description

Light guide plate of backlight unit and backlight unit having same {A light guided panel and backlight unit having the same}

1 is an exploded perspective view of a conventional liquid crystal display device.

2A is a perspective view of a light guide plate according to an embodiment of the present invention.

FIG. 2B is a rear view of FIG. 2A; FIG.

FIG. 2C is a cross-sectional view taken along the line AA ′ of FIG. 2A;

3A is a perspective view of a light guide plate according to another embodiment of the present invention.

3B is a back view of FIG. 3A.

3C is a cross-sectional view taken along the line AA 'of FIG. 3A.

5 is an explanatory diagram illustrating an operation of an embodiment of the present invention.

5A and 5B are graphs showing luminance according to angles of a conventional light guide plate and simulation image photographs according thereto.

6A and 6B are graphs showing luminance according to angles of the light guide plate according to the present invention, and simulation image photographs according thereto.

7 is an exploded perspective view of a backlight unit according to an embodiment of the present invention.

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

100: light guide plate 110: first V-type groove

120: second V-type groove 130: third V-type groove

200: light guide plate 210: first projection

220: second protrusion 230: third protrusion

400: backlight unit 410: light source

420: light guide plate 430: prism sheet

440: Reflective Sheet

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide panel of a backlight unit applied to a liquid crystal display device and a backlight unit using the same. More specifically, a V-shaped groove intersecting each other on a reflective surface is provided. It relates to a light guide plate of the backlight unit is formed and a backlight unit having the same.

As the information and communication industry is rapidly developed, the use of display devices is rapidly increasing, and in recent years, display devices capable of satisfying conditions of low power, light weight, thinness, and high resolution are required. In response to these demands, display devices using liquid crystal displays or organic light emitting characteristics have been developed.

Thin Film Transistor-Liquid Crystal Display (TFT-LCD), which has excellent color reproducibility, low power consumption, and is made thin, is one of the most widely used flat panel display devices. The liquid crystal display panel includes a liquid crystal display panel into which a liquid crystal is injected, a backlight unit used under a liquid crystal display panel, and a driving unit for driving the liquid crystal display panel.

FIG. 1 is an exploded perspective view for explaining a conventional liquid crystal display device, in which a liquid crystal display panel 10 on which an image is displayed and a backlight unit 30 for providing light to the liquid crystal display panel 10 are illustrated.

The liquid crystal display panel 10 includes two substrates disposed to face each other, a liquid crystal layer interposed between the two substrates, and a pixel region is formed by a plurality of gate lines and data lines arranged in a matrix form on the substrate. Is defined. A thin film transistor for controlling a signal supplied to each pixel and a pixel electrode connected to the thin film transistor are formed on a substrate where the gate line and the data line cross each other, and a color filter and a common electrode are formed on the other substrate.

The backlight unit 30 may change the distribution of light provided from the light source 32, the light guide plate 31, and the light guide plate 31 provided to the liquid crystal display panel 10 to change the distribution of light provided from the light source 32. The optical sheet 34 makes the luminance distribution uniform and improves the vertical incidence, and the reflective sheet 33 reflects the light emitted to the light guide plate 31 to the light guide plate 31.

The light source 32 is composed of a lamp 32a disposed on the side of the light guide plate 31, and a reflecting plate 32b for reflecting light emitted from the lamp 32a to the light guide plate 31, and the optical sheet 34 is The diffusion sheet 34a diffuses the light incident from the light guide plate 31 toward the liquid crystal display panel 10, and the prism sheet 34b concentrates the diffused light to improve vertical incidence.

As described above, in the conventional liquid crystal display device, the optical sheet 34 is usually composed of one diffusion sheet 34a and two prism sheets 34b, so that the brightness of the backlight unit is increased and the brightness is increased. There is a low problem, and improvement efforts are being made.

The present invention has been proposed to solve the above-mentioned conventional problems, and an object of the present invention is to provide a light guide plate of a backlight unit and a backlight unit using the same by forming a V-shaped groove in a light guide plate to increase brightness and uniformity. There is.

One side of the present invention is a light guide plate having a pattern formed on at least one surface, wherein the pattern formed on the first surface of the light guide plate includes a plurality of first V-shaped grooves extending in a first direction and a plurality of first extending in a second direction. 2 V-shaped grooves are cross-aligned with each other, the depth of the first V-shaped groove is characterized in that the intaglio pattern is formed smaller than the depth of the second V-shaped groove.

According to another aspect of the present invention, a light guide plate having a pattern formed on at least one surface thereof, wherein the pattern formed on the first surface of the light guide plate has a first protrusion formed in reverse phase to the first V-shaped groove and the second V-shaped groove of the claim 1, respectively. And an embossed pattern provided with a second protrusion.

Another aspect of the present invention provides a backlight unit including a light guide plate having a pattern, wherein the pattern of the light guide plate includes a plurality of first V-shaped grooves extending in a second direction and extending in a third direction on a first surface thereof. The second V-shaped grooves are arranged to cross each other, the depth of the first V-shaped grooves is characterized in that the intaglio pattern is formed smaller than the depth of the second V-shaped grooves.

In another aspect of the present invention, there is provided a backlight unit including a light guide plate having a pattern, wherein the pattern of the light guide plate includes: a first protrusion having an embossment corresponding to each of the first V-shaped grooves and the second V-shaped grooves described above on a first surface; It is characterized in that the pattern of the relief provided with the second projection.

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

FIG. 2A is a perspective view of a light guide plate according to an embodiment of the present invention, FIG. 2B is a rear view of FIG. 2A, and FIG. 2C is a cross-sectional view taken along line AA ′ of FIG. 2A. According to this, the light guide plate 100 includes an output surface 101 for outputting light incident from the light source 103 and a reflection surface 102 for preventing the incident light from leaking, and each output surface 101 and A pattern is formed on the reflective surface 102.

The pattern is engraved and the reflective surface 102 is formed with a plurality of first V-shaped grooves 110 in a direction parallel to the third V-shaped grooves to be described later, and the first V-shaped grooves 110 are the reflective surfaces 102. The angle of light reflected from) does not spread from side to side, but collects at the center.

The second V-shaped groove 120 serves to maintain the exit angle of the reflected light at the light emitting surface 101 at a constant level, and the depth of the first V-shaped groove 110 in the direction perpendicular to the first V-shaped groove 110 is maintained. More deeply and continuously. At this time, the depth of the second V-shaped groove 120 is preferably about 2 to 4 times the depth of the first V-shaped groove 110.

The vertical section of the second V-shaped groove 120 forms a triangle. The first angle θ1 constituting the V-shaped angle among the vertices of the triangle is 140 ° to 170 °, and the cross section of the second V-shaped groove surface is formed. It is preferable that the 2nd angle (theta) 2 which is a side where a light source is located among the vertex angles of a triangle is 1.3-2.3 degrees. This is because it is difficult to set the exit angle at the light exit surface 101 to 65 to 75 ° when the angle is out of the angle.

In addition, the pitch of the second V-shaped grooves 120 may be larger than the pitch of the first V-shaped grooves 110. The pitch is generally 0.003mm to 0.3mm of the panel and can be adjusted according to the pixel pitch of the display panel to prevent moire phenomenon.In addition, the second V-shaped groove 120 is gradually moved from the light source side to the opposite side of the light source. The pitch can be made smaller. In addition, the grooves of each of the second V-shaped grooves 120 may be spaced at a predetermined interval.

In this case, a plurality of third V-shaped grooves 130 may be continuously formed in the light emitting surface 101 in the same direction as the irradiation direction of the light source. The third V-shaped groove 130 is formed in the light exit surface 101, and serves to adjust the angle of the exit angle.

Meanwhile, in this embodiment, the direction of the third V-shaped groove 130 is the same direction as the incident direction of the light source of the light guide plate 100, and the direction of the first V-shaped groove 110 is the third V-shaped groove 130. The direction of the second V-shaped groove 120 is shown to be perpendicular to the direction of the first V-shaped groove 110, but the direction of each groove is easy at the level of those skilled in the art Will be able to change.

3A is a perspective view of a light guide plate according to another embodiment of the present invention, FIG. 3B is a rear view of FIG. 3A, and FIG. 3C is a cross-sectional view taken along line AA ′ of FIG. 3A. According to this, the light guide plate 200 includes a light exit surface 201 for outputting light incident from the light source 203 and a reflection surface 202 for preventing the incident light from leaking, and each light exit surface 201 and A pattern is formed on the reflective surface 202.

The pattern formed on the reflective surface 201 is embossed in a reverse phase to the pattern of the first embodiment, and the plurality of first protrusions 210 are formed on the reflective surface 202 in a direction parallel to the third protrusion 230 to be described later. The first protrusion 210 serves to collect the angle of the light reflected from the reflective surface 202 to the center without spreading from side to side.

The second protrusion 220 serves to keep the reflected light at a constant exit angle at the light exit surface 201, and is continuously formed higher than the height of the first protrusion 210 in the vertical direction with the first protrusion 210. . At this time, the height of the second protrusion 220 is preferably about 2 to 4 times higher than the height of the first protrusion 210.

The vertical cross section of the second protrusion 220 forms a triangle. The first angle θ3 constituting the V-shaped vertex of the vertex of the triangle is 140 ° to 170 °, and the triangle formed by the cross section of the second protrusion 220 is formed. It is preferable that the second angle θ4 on the opposite side to which the light source is located is set to be 1.3 ° to 2.3 °. This is because it is difficult to set the exit angle at the exit surface to 65 to 75 ° when the angle is out of the angle.

In addition, the pitch of the second protrusion 220 is preferably larger than the pitch of the first V-shaped groove 210, and the pitch is generally 0.003mm to 0.3mm of the panel to prevent moire phenomenon. The pitch of the second V protrusion 220 may decrease from the light source side toward the opposite side of the light source.

In addition, the pitches of the second protrusions 220 may be spaced apart at predetermined intervals.

In this case, a plurality of third protrusions 230 may be continuously formed on the light emitting surface 201 in the same direction as the irradiation direction of the light source. The third protrusion 230 is formed on the light exit surface 201 to adjust the angle of the exit angle. The third protrusion 230 is formed in an embossed pattern corresponding to the third V-shaped groove 130 of the first embodiment.

Meanwhile, in this embodiment, the direction of the third protrusion 230 is the same direction as the incident direction of the light source of the light guide plate 200, and the direction of the first protrusion 210 is the same as the direction of the third protrusion 230. Although the direction of the second protrusion 220 is shown to be perpendicular to the direction of the first protrusion 210, the extension direction of each protrusion may be easily changed at the level of those skilled in the art.

Next, the operation of the light guide plate according to the present invention will be described with reference to the drawings. However, since the first embodiment and the second embodiment are related to the intaglio and the embossment corresponding to each other, the description will be made with reference to the second embodiment on the page, but those skilled in the art can recognize the same operation in the first embodiment. will be. 4 is an explanatory view for explaining the action of the first protrusion of the light guide plate according to the present invention, and FIG. 5 is an explanatory view for explaining the action of the second protrusion.

According to FIG. 4, the light reflected from the reflective surface 202 does not spread from side to side due to the formation of the first protrusion 210 of the light guide plate 200.

In addition, according to FIG. 5, the light incident from the light source is reflected by the second protrusion 220 at a specific angle, so that the exit angle of the light exit surface is maintained at 65 to 75 °, and the front prism sheet 300 faces the front side. Emitted at 0 °.

6A and 6B are graphs showing luminance according to the angle of a conventional light guide plate and simulation image photographs according to the present invention, and FIGS. 7A and 7B are graphs showing the luminance of a light guide plate according to the present invention and the resulting light. Simulation video.

According to this, in the light guide plate according to the prior art, the light is spread from side to side, and the luminance is lowered.

Manufacturing of the light guide plate according to the present invention may be made by injection molding. The light guide plate may be manufactured by forming a reverse phase of the pattern of the light guide plate on both cores of the mold. However, in the case of the second embodiment, since the mold core having the V-shaped groove formed by the bite can be manufactured directly, the manufacturing method of the second embodiment will be simpler than the first embodiment in terms of ease of manufacture. In the first embodiment, an embossed protrusion corresponding to the V-shaped groove is to be formed, because it is not easy to directly form the embossed protrusion, and thus the core must be subjected to injection molding.

Next, a backlight unit including a light guide plate according to an exemplary embodiment of the present invention will be described. 7 is an exploded perspective view of a backlight unit according to an embodiment of the present invention. Accordingly, the backlight unit 400 makes the luminance distribution of the light provided from the light guide plate 420 and the light guide plate 420 changing the distribution of light provided from the light source 410 uniform. The prism sheet 430 improves vertical incidence and the reflective sheet 440 reflects light emitted to the rear of the light guide plate 420 to the light guide plate 420. Unexplained reference numeral 450 is a mold frame.

The light guide plate 420 according to the present invention is formed of a transparent material, such as an acrylic resin, in which a protrusion (or groove) in one direction is formed on the light exit surface, and protrusions (or grooves) in which depth and pitch cross each other on the reflection surface are formed. It consists of a plate (cuboid).

Although the present invention has been described primarily with reference to the above embodiments, many other possible modifications and variations can be made without departing from the spirit and scope of the invention. For example, changing the angle of each pattern, changing the depth of the pattern, changing the width, and so on. In addition, those skilled in the art will recognize that the configuration of the backlight unit including the light guide plate according to the present invention as an embodiment may be implemented in various modifications.

As described above, the light guide plate according to the present invention has a pattern having a shape intersecting in different directions on the reflective surface, thereby narrowing the reflection angle spreading from side to side, and maximizing the reflection characteristic to realize the increase and uniformity of the central luminance. There is.

The scope of the above-described invention is defined in the following claims, not bound by the description in the specification body, all modifications and variations that fall within the equivalent scope of the claims will fall within the scope of the invention.

Claims (21)

In the light guide plate having a pattern formed on at least one surface, In the pattern formed on the first surface of the light guide plate, a plurality of first V-shaped grooves extending in a first direction and a plurality of second V-shaped grooves extending in a second direction cross each other and are arranged in the first V-shaped groove. The depth of the light guide plate comprising a pattern of the intaglio is formed smaller than the depth of the second V-shaped groove. The method of claim 1, The light guide plate further comprises a plurality of third V-shaped grooves extending in the third direction on the second surface of the light guide plate. The method of claim 1, The first V-shaped groove is a light guide plate, characterized in that 1/2 to 1/4 of the depth of the second V-shaped groove. The method of claim 1, A light guide plate, characterized in that the first angle formed by both inclined surfaces of the vertex angle of the triangle formed by the cross section of the second V-shaped groove is 140 ° to 170 °. The method of claim 4, wherein The light guide plate, characterized in that the second angle in the direction of the light source side of the vertex angle of the triangle formed by the cross section of the second V-shaped groove is 1.3 ° to 2.3 °. The method of claim 1, The first direction is the same direction as the incident direction of the light source of the light guide plate, and the second direction is perpendicular to the second direction. The method of claim 1, The pitch of the second V-shaped groove is greater than the pitch of the first V-shaped groove. The method of claim 7, wherein The pitch of the second V-shaped groove is a light guide plate, characterized in that 0.003 to 0.3mm. In the light guide plate having a pattern formed on at least one surface, The pattern formed on the first surface of the light guide plate is a light guide plate having a first protrusion and a second protrusion having a reverse phase in the first V-shaped groove and the second V-shaped groove of claim 1, respectively. . The method of claim 9, The second light guide plate of the light guide plate, characterized in that the third projection of the embossed to the reverse phase to the third V-shaped groove of claim 1 is further provided. The method of claim 9, The first projection is a light guide plate, characterized in that 1/2 to 1/4 of the height of the second projection. The method of claim 9, The light guide plate, characterized in that the protruding first angle of the vertex angle of the triangle formed by the cross section of the second protrusion is 140 ° to 170 °. The method of claim 9, The light guide plate, characterized in that the second angle of the vertex angle of the triangle formed by the cross section of the second protrusion is the opposite angle to which the light is incident is 1.3 ° to 2.3 °. The method of claim 9, The extending direction of the first protrusion is the same direction as the incident direction of the light source of the light guide plate, the extending direction of the second protrusion is perpendicular to the extending direction of the first protrusion. The method of claim 9, The light guide plate further comprises a plurality of third V-shaped grooves extending in the third direction on the second surface of the light guide plate. The method of claim 9, The pitch of the second protrusion is greater than the pitch of the first protrusion. The method of claim 9, The pitch of the second protrusion is a light guide plate, characterized in that 0.003mm to 0.3mm. In the backlight unit including a light guide plate formed with a pattern, In the pattern of the light guide plate, a plurality of first V-shaped grooves extending in a second direction and a plurality of second V-shaped grooves extending in a third direction cross each other and are arranged in a depth of the first V-shaped groove. The back light unit, characterized in that the intaglio pattern is formed smaller than the depth of the second V-shaped groove. The method of claim 18, And a plurality of third V-shaped grooves extending in a third direction on the second surface of the light guide plate. In the backlight unit including a light guide plate formed with a pattern, The pattern of the light guide plate is an embossed pattern having a first protrusion and a second protrusion having an embossed portion corresponding to the first V-shaped groove and the second V-shaped groove of claim 1, respectively. The method of claim 20, The second surface of the light guide plate is further provided with a third projection of the embossed shape of the shape corresponding to the third V-shaped groove of claim 1.

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