KR102158906B1 - Light diffusion structure and backlight unit including the same - Google Patents

Abstract

The backlight unit is started. The backlight unit includes a light guide plate; A light source array in which light sources are arranged on a circuit board to be spaced apart from each other by a predetermined distance and disposed on one side of the light guide plate; And disposed above the light source array so as to be placed on the light source array, facing one side of the light guide plate, and connected to a light source receiving unit accommodating the light source and the light source receiving unit to be disposed above the light source and convex in the direction of the light source. And a light diffusion structure including a light direction conversion unit including at least one reflective surface facing light irradiated from the light source, wherein the light diffusion structure includes the light source receiving unit and the light direction conversion unit Has an array structure arranged in series, wherein the reflective surface of the light direction conversion unit is a first reflective surface that reflects light irradiated from the light source, and one surface of the light source receiving unit facing the first reflective surface is the first half It is characterized in that it is a second reflective surface that reflects the light reflected from the slope to face the light guide plate.

Description

A light diffusion structure and a backlight unit including the same

The present invention relates to a backlight unit, and more particularly, to a backlight unit that provides a high luminance backlight with a small number of light sources.

Typically, a liquid crystal display device, which is a type of light-receiving flat panel display, does not emit light by itself to form an image, and light is incident from the outside to form an image. To this end, a backlight unit is installed on the rear surface of the liquid crystal display to irradiate light. This backlight unit is used not only in a liquid crystal display device but also in a surface light source device such as an illumination signboard.

The backlight unit is classified into a direct light type and an edge light type according to the arrangement of the light source. In the direct light-emitting type, a lamp installed directly under the liquid crystal panel irradiates light directly onto the liquid crystal panel. In the edge-emission type, a lamp installed at the edge of a light guide panel (LGP) irradiates light, and the irradiated light is transmitted to the liquid crystal panel through the light guide panel.

The edge-emission type can use a line light source and a point light source as a light source. As a typical line light source, there is a cold cathode fluorescent lamp (CCFL) in which electrodes at both ends are installed in a tube. In addition, as a point light source, there is a light emitting diode (LED).

CCFL has the advantage that it can emit strong white light, can obtain high brightness and high uniformity, and can design a large area. However, this CCFL has a disadvantage that it is operated by a high frequency AC signal and has a narrow operating temperature range. In terms of brightness and uniformity, LEDs

Performance is poor compared to CCFL. However, this LED is operated by a DC signal, has a long service life, a wide operating temperature range, and has the advantage of being able to be thinner.

1 is a schematic cross-sectional view of a conventional general edge-emitting type backlight unit.

Referring to FIG. 1, in the conventional backlight unit, a light source 20 is disposed at one edge of the light guide plate 10 to be spaced apart from the light incident end surface 11 of the light guide plate 10 by a predetermined distance. In this structure, the light source 20 emits light toward the light-incident end surface 11 of the light guide plate 10. At this time, in the arrangement of the light source 20, the radiation angle of the light source 20 and the incident distance from which the light is incident to the light guide plate 10 are taken into account, and in order to increase the brightness of the light guide plate 10, the light source ( It is common to narrow the distance through which light is incident from 20) to the light guide plate 10, and in this case, the number of light sources 20 increases.

Accordingly, the conventional backlight unit required a large number of light sources 20 to increase the luminance of the light guide plate 10, which served as a factor of increasing the manufacturing cost of the backlight unit.

Accordingly, a problem to be solved by the present invention is to provide a backlight unit in which a high-brightness backlight can be provided with only a small number of light sources, a change in uniformity and luminance of light of the backlight unit is prevented, and a heat dissipation effect is increased.

Another object is to provide a backlight unit in which light leakage can be prevented.

A backlight unit according to an embodiment of the present invention for solving the above-described problem includes a light guide plate; A light source array in which light sources are arranged on a circuit board to be spaced apart from each other by a predetermined distance and disposed on one side of the light guide plate; And disposed above the light source array so as to be placed on the light source array, facing one side of the light guide plate, and connected to a light source receiving unit accommodating the light source and the light source receiving unit to be disposed above the light source and convex in the direction of the light source. And a light diffusion structure including a light direction conversion unit including at least one reflective surface facing light irradiated from the light source, wherein the light diffusion structure includes the light source receiving unit and the light direction conversion unit in a longitudinal direction of the light source receiving unit Has an array structure arranged in series, wherein the reflective surface of the light direction conversion unit is a first reflective surface that reflects light irradiated from the light source, and one surface of the light source receiving unit facing the first reflective surface is the first half It is characterized in that the second reflection is directed toward the light guide plate by reflecting the light reflected from the slope.

In an embodiment, the light source receiving unit may include a base portion extending to a predetermined length and having the light source disposed in the center; And a sidewall portion disposed perpendicular to the base portion and parallel to a length direction of the base portion, and the light direction conversion portion may be provided concavely from the sidewall portion to an inner direction of the sidewall portion.

In one embodiment, the base unit includes: a light source arranging unit having a hole structure for accommodating the light source; And a light guide plate stopper part that extends higher than the height of the light source as an end of the base part extending left and right from the light source placing part, and corresponding to one side of the light guide plate to support the light guide plate, and the side wall part includes the light source placing part and It can cover the side of the light guide plate stopper part.

In one embodiment, the base portion may have a cross-sectional shape bent in a bow shape.

In one embodiment, the length of the light source accommodating portion may be greater than or equal to a pitch between light sources on the light source array.

In one embodiment, the width of the light diffusing structure may be equal to the thickness of the light guide plate or 0.2 mm or less than the thickness of the light guide plate.

According to the backlight unit according to the present invention, a high-brightness backlight can be provided with only a small number of light sources, a change in uniformity and luminance of light of the backlight unit is prevented, and a heat dissipation effect can be increased.

In addition, there is an advantage in that light leakage can be prevented.

1 is a cross-sectional view illustrating a conventional backlight unit.
2 is a perspective view illustrating a backlight unit according to an embodiment of the present invention.
3 is an enlarged perspective view illustrating the light diffusion structure shown in FIG. 2.
4 is a perspective view of the light diffusion structure as viewed from below of the light diffusion structure shown in FIG. 2.
5 is a cross-sectional view illustrating an assembled state of the backlight unit shown in FIG. 1.
6 is a cross-sectional view illustrating a path through which light from a light source of a backlight unit according to an embodiment of the present invention is incident on a light guide plate.
7 is a perspective view illustrating another example of the light diffusion structure shown in FIG. 2.

Hereinafter, a light diffusion structure and a backlight unit including the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the present invention, various modifications may be made and various forms may be applied, and specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific form disclosed, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals have been used for similar elements. In the accompanying drawings, the dimensions of the structures are shown to be enlarged than the actual size for clarity of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

The terms used in the present application are used only to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility of being added.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

The present invention discloses a light diffusion structure and a backlight unit including the same. Since the light diffusion structure includes a backlight unit, it will be described in detail in the process of describing the backlight unit below.

2 is a perspective view illustrating a backlight unit according to an embodiment of the present invention, FIG. 3 is an enlarged perspective view of the light diffusion structure shown in FIG. 2, and FIG. 4 is a view illustrating the light diffusion structure shown in FIG. It is a perspective view of the light diffusion structure viewed from below.

2 to 4, a backlight unit according to an embodiment of the present invention includes a light guide plate 100, a light source array 200, and a light diffusion structure 300.

The light guide plate 100 guides light incident from the light source array 200 and the light diffusion structure 300 in the direction of a liquid crystal panel of the display.

The light source array 200 includes a circuit board 210 and a plurality of light sources 220 arranged to be spaced apart from each other by a predetermined distance on the circuit board 210. The light source 220 may be an LED. For example, the CSP 1313 PKG can be used for the LED.

The light diffusion structure 300 widely diffuses an irradiation range of light irradiated from the light source 220 of the light source array 200. The light diffusion structure 300 includes a light source receiving unit 310 and a pair of light direction switching units 320, and the light source receiving unit 310 and a pair of light direction changing units 320 are provided with a light source receiving unit ( 310) has an array structure continuously arranged in the longitudinal direction. The number of light source accommodating units 310 and a pair of light direction switching units 320 is the same as the number of light sources 220 of the light source array 200.

The light source accommodating part 310 extends to a predetermined length and accommodates a light source in the center of the length. The light source receiving part 310 includes a base part 311 and a side wall part 312.

The base part 311 extends to a predetermined length, and a light source 220 accommodated in the light source receiving part 310 is disposed in the center. The base part 311 includes a light source arrangement part 3111 and a light guide plate stopper part 3112. The light source arrangement part 3111 is provided in a hole structure for accommodating the light source 220, and the light guide plate stopper part 3112 is an end of the base part 311 extending left and right from the light source arrangement part 3111, and the light source 220 It extends higher than the height of ). Although there is no particular limitation on the shape of the base part 311, it is preferable to have a cross-sectional shape bent in a bow shape. The length of the base part 311 may have a length greater than or equal to the pitch between the light sources 220 on the light source array 200. For example, the length of the base part 311 may be the same as the pitch between the light sources 220.

The side wall portion 312 is disposed to be perpendicular to the base portion 311 and parallel to the length direction of the base portion 311. The side wall portion 312 covers the side surfaces of the light source arrangement portion 3111 and the light guide plate stopper portion 3112. The height of the sidewall portion 312 may have a height greater than or equal to the height of the light guide plate stopper portion 3112 of the base portion 311.

The light source accommodating part 310 corresponds to the thickness surface of one side of the light guide plate 100 on the light source array 200. For example, the light source receiving unit 310 may correspond to a lower thickness surface (hereinafter referred to as a light incident cross-section 110) extending in the transverse direction among four thickness surfaces of the light guide plate 100. At this time, the light guide plate stopper part 3112 supports the light guide plate 100 to keep the light incident end surface 110 of the light guide plate 100 spaced apart from the light source 220.

Each light direction conversion unit 320 reflects a part of light irradiated from the light source 220 toward the inner surface of the light source receiving unit 310. To this end, each light direction switching unit 320 is connected to the light source receiving unit 310 and disposed above the light source 220, and is convex in the direction of the light source 220 to face at least one light irradiated from the light source. It includes a reflective surface 321. Each of these light direction conversion units 320 is provided concavely from the upper end of each sidewall portion 312 of the light source accommodating portion 310 toward the inside of the sidewall portion 312. A surface that is not parallel to the sidewall portion 312 in the concave shape is the reflective surface 321.

There is no particular limitation on the shape of the pair of light direction conversion units 320, and any type of reflective surface 321 capable of reflecting light toward the left and right sides of the light source receiving unit 310 may be used. For example, each light direction conversion unit 320 may be provided to be concave to include one arc-shaped surface or two adjacent surfaces as the reflective surface 321.

As an example, each light direction switching unit 320 may be concave in a concave shape as shown in FIG. 1 into an inverted triangular shape when viewed from a surface parallel to the sidewall portion 312 as a front. In this case, two surfaces symmetrically adjacent to each other become the reflective surface 321.

The material of the light diffusion structure 300 is not particularly limited, and may be made of stainless steel or aluminum, which is a metal, in order to increase the heat dissipation effect. In order to increase the reflection efficiency of light on the reflective surface, the inner surface of the light source receiving unit 310 may be mirror polished and silver plated.

In addition, the width of the light diffusing structure 300 may be equal to the thickness of the light guide plate 100 or 0.2 mm or less than the thickness of the light guide plate 100.

Meanwhile, the light diffusion structure 300 may further include a light guide plate holder 330.

The light guide plate holder part 330 is disposed on the left and right sides of the light direction switching part 320 so as to be parallel to the length direction of the light source receiving part 310, and is higher than the height of the light guide plate stopper part 3112 from the upper end of the light source receiving part 310. It is extended high. For example, as shown in FIG. 3, the light guide plate holder part 330 may be provided only in the direction of one of the side wall parts 312 facing each other. As another example, as shown in FIG. 7, the light guide plate holder portion 330 may be provided in both the sidewall portions 312 direction. 7 is a perspective view illustrating another example of the light diffusion structure shown in FIG. 2.

The light guide plate holder part 330 allows the light guide plate 100 to be easily positioned at the upper end of the light diffusion structure 300 when the light diffusion structure 300 is disposed to correspond to the light incident end surface 110 of the light guide plate 100. That is, when at least one surface perpendicular to the light incident end surface 110 of the light guide plate 100 is in close contact with the inner surface of the light guide plate holder part 330, the light diffusion structure 300 is attached to the light incident end surface 110 of the light guide plate 100. It may correspond exactly, and the light guide plate 100 may be easily positioned at the upper end of the light diffusion structure 300.

Hereinafter, a process in which light is incident on the light guide plate of the backlight unit according to an embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG. 5 is a cross-sectional view illustrating an assembled state of the backlight unit illustrated in FIG. 1, and FIG. 6 is a cross-sectional view illustrating a path through which light from a light source of the backlight unit according to an embodiment of the present invention enters the light guide plate.

5 and 6, light from the light source 220 is irradiated toward the light incident end surface 110 of the light guide plate 100. At this time, some of the light is directly incident on the light-incident cross-section 110 through the open upper portion of the light-diffusion structure 300, and the rest of the light is directed toward the pair of light direction conversion units 320 of the light-diffusion structure 300. Is investigated.

Some of the light irradiated toward the pair of light direction conversion units 320 is reflected from the reflective surface 321 of each light direction conversion unit 320 and proceeds toward the left and right sides of the light source receiving unit 310, and then Light propagating to the left and right of the light source accommodating part 310 is reflected from the inner surface of the base part 311 and proceeds in the direction of the light guide plate 100, and is incident on the light incident end surface 110 of the light guide plate 100.

The reflective surface 321 of each light direction conversion unit 320 becomes a first reflective surface according to the path of light travel, and the inner surface of the base part 311 of the light source receiving unit 310 is a second reflective surface. do.

The use of the backlight unit according to an embodiment of the present invention has the following advantages.

First, a direction so that a part of the light irradiated from the light source 220 is not directly incident on the light guide plate 100 and travels widely to the left and right sides of the light source 220 through the first reflective surface of the pair of light direction switching units 320. After the conversion, the second reflective surface facing the first reflective surface is re-directed toward the light guide plate 100 to implement a process of light incident to the light guide plate 100, so that the light irradiated from one light source 220 is The number of light sources 220 used in the backlight unit by allowing light to be incident on the entire light incident end surface 110 of the light guide plate 100 even with a small number of light sources 220 even with a small number of light sources 220 There is an advantage that can reduce the. Therefore, there is an advantage of providing a high-brightness backlight with only a small number of light sources.

Second, the light diffusing structure 300 is provided at the left and right ends of the light source accommodating part 310 and is provided at the light-incident end face of the light guide plate 100 by a light guide plate stopper part corresponding to the light-incident end face 110 of the light guide plate 100. Since 110) is kept away from the light source 220, the distance that the light irradiated from the light source 220 is reflected on the first and second reflective surfaces is constant, and accordingly, the light guide plate 100 always has a constant illuminance. There is an advantage in that the uniformity of light and the luminance of the backlight unit are prevented from changing because light of the backlight can be incident.

Third, since the light diffusing structure 300 accommodates the light source 220 inside, the light diffusion structure 300 acts as a heat dissipation against heat generated by the light source 220, thereby increasing the heat dissipation effect of the backlight unit.

Fourth, when the light guide plate 100 and the light diffusion structure 300 are arranged to correspond to each other by the light guide plate holder part 330 of the light diffusion structure 300, the light diffusion structure 300 is formed at the light incident cross-section of the light guide plate 100. 110 ), and the light guide plate 100 can be easily positioned at the upper end of the light diffusion structure 300. In addition, since the light guide plate holder part 330 extends higher than the height of the light guide plate stopper part 3112 corresponding to the light incident end surface 110 of the light guide plate 100, the light incident end surface 110 and the light source receiving part of the light guide plate 100 By covering the boundary between the upper ends of the light guide plate 310, light incident on the light guide plate 100 can be prevented from leaking between the boundary between the light incident end surface 110 of the light guide plate 100 and the upper end of the light source receiving part 310 . Accordingly, there is an advantage of preventing light leakage from the backlight unit by the light guide plate holder 330.

Reference numeral 411 in FIG. 5 is a first optical sheet, and 412 is a second optical sheet. The first optical sheet 411 and the second optical sheet 412 are stacked on one surface of the light guide plate 100. The first optical sheet 411 and the second optical sheet 412 are sheets for increasing light efficiency, and change the metering light to front light and collect light that spreads in all directions to increase luminance.

Reference numeral 500 in FIG. 5 is a reflective sheet. The reflective sheet 500 is stacked on the other side of the light guide plate 100, that is, on the opposite side of the side on which the first optical sheet 411 and the second optical sheet 412 are stacked. Prevent loss.

Reference numeral 600 in FIG. 5 denotes a frame. The frame 600 is coupled to all sides of the light guide plate 100 to accommodate and fix each component of the backlight unit.

The description of the presented embodiments is provided to enable any person skilled in the art to use or implement the present invention. Various modifications to these embodiments will be apparent to those of ordinary skill in the art, and the general principles defined herein can be applied to other embodiments without departing from the scope of the present invention. Thus, the present invention is not to be limited to the embodiments presented herein, but is to be construed in the widest scope consistent with the principles and novel features presented herein.

Claims (11)

A light source accommodating portion extending to a predetermined length and including a base portion accommodating a light source in the center of the length and a pair of sidewall portions vertically erected from both sides of the base portion in the longitudinal direction; And
And a pair of light direction switching portions provided to be concave in the direction of the side wall portions facing from the upper end portions of each of the side wall portions,
Each of the light direction conversion units is convex in the direction of the light source and includes at least one reflective surface facing light irradiated from the light source, and each light direction conversion unit is spaced apart from each other so that each light direction conversion unit is open. ,
The light source receiving unit and the light direction switching unit has an array structure in which the light source receiving unit is continuously arranged in a longitudinal direction,
The reflective surface of the light direction conversion unit is a first reflective surface that reflects light irradiated from the light source, and an inner surface of the base unit facing the first reflective surface is reflected from the first reflective surface. The second reflective surface that reflects light,
Light diffusion structure for backlight unit. delete The method of claim 1,
The base portion,
A light source arranging unit having a hole structure for accommodating the light source; And
And a light guide plate stopper portion extending higher than a height of the light source as an end of the base portion extending left and right from the light source arranging portion,
The side wall portion, characterized in that covering the side surface of the light source arrangement portion and the light guide plate stopper portion,
Light diffusion structure for backlight unit. The method of claim 3,
The base portion is characterized in that it has a cross-sectional shape bent in a bow shape,
Light diffusion structure for backlight unit. The method of claim 1,
The length of the light source accommodating portion is characterized in that greater than or equal to a pitch between light sources disposed along the length direction of the array structure,
Light diffusion structure for backlight unit. Light guide plate;
A light source array in which light sources are arranged on a circuit board to be spaced apart from each other by a predetermined distance and disposed on one side of the light guide plate; And
And a light diffusion structure disposed above the light source array to be placed on the light source array and facing one side of the light guide plate,
The light diffusion structure,
A light source accommodating portion including a base portion extending to a predetermined length and accommodating a light source in the center of the length and a pair of sidewall portions vertically erected from both sides of the length direction of the base portion, and facing at the upper end of each sidewall portion It includes a pair of light direction switching units provided to be concave in the direction of the side wall,
Each of the light direction conversion units is convex in the direction of the light source and includes at least one reflective surface facing light irradiated from the light source, and each light direction conversion unit is spaced apart from each other so that each light direction conversion unit is open. ,
The light diffusion structure has an array structure in which the light source accommodating portion and the light direction switching portion are continuously arranged in the longitudinal direction of the light source accommodating portion,
The reflective surface of the light direction conversion unit is a first reflective surface that reflects light irradiated from the light source, and an inner surface of the base unit facing the first reflective surface is reflected from the first reflective surface. A second reflective surface that reflects light to face the light guide plate,
Backlight unit. delete The method of claim 6,
The base portion,
A light source arranging unit having a hole structure for accommodating the light source; And
An end of the base portion extending from the light source arranging portion to the left and right, extending higher than the height of the light source, and corresponding to one side of the light guide plate to support the light guide plate,
The side wall portion, characterized in that covering the side surface of the light source arrangement portion and the light guide plate stopper portion,
Backlight unit. The method of claim 8,
The base portion is characterized in that it has a cross-sectional shape bent in a bow shape,
Backlight unit. The method of claim 6,
The length of the light source accommodating portion is characterized in that the pitch between the light sources on the light source array or more
Backlight unit. The method of claim 6,
The width of the light diffusing structure is the same as the thickness of the light guide plate or 0.2 mm or less than the thickness of the light guide plate.
Backlight unit.

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