KR20080002652A - Light emitting diode array and and backlight unit using the same - Google Patents

Abstract

An LED array and a backlight unit using the same are provided to dispose a light guide member for controlling the orienting direction of light emitted from LEDs between the LED array and a light guide plate, thereby removing a hot spot through the light guide member. An LED(Light Emitting Diode) array(100) comprises plural LEDs(101) and a light guide member(121). The plural LEDs are disposed in at least one line at particular intervals. The light guide member is disposed in a position adjacent to the plural LEDs and controls the direction of light emitted from the LEDs. The light guide member is composed of a lower plate, an upper plate, and plural partitions(123) disposed at regular intervals between the upper and lower plates.

Description

LIGHT EMITTING DIODE ARRAY AND AND BACKLIGHT UNIT USING THE SAME}

1 is a cross-sectional view showing an edge-type backlight unit according to the prior art.

Figure 2 is a plan view of the edge-type backlight unit according to the prior art, a plan view showing the arrangement of the light emitting element array and the light guide plate.

3 is a cross-sectional view showing a backlight unit according to an embodiment of the present invention, a cross-sectional view showing a state where the light guide member is disposed between the light emitting element array and the light guide plate.

4 is a plan view showing a backlight unit according to an embodiment of the present invention, a plan view showing a state where the light guide member is disposed between the light emitting element array and the light guide plate.

5 is a plan view of the light guide member provided in the backlight unit according to an embodiment of the present invention.

6 is a front view of the light guide member provided in the backlight unit according to an embodiment of the present invention.

7 is a cross-sectional view showing a backlight unit according to another embodiment of the present invention, wherein the light emitting device is mounted on the side of the light emitting device array.

-Explanation of symbols for the main parts of the drawings-

100: light emitting element array 101: light emitting element

103: light guide plate 105: light reflector

107: reflector plate 109: diffusion sheet

111: prism sheet 113: protective sheet

115: mold frame 117: array substrate

119: top case 121: optical guide member

123: bulkhead

The present invention relates to a liquid crystal display device, and more particularly, to a light emitting device array capable of removing a hot spot by mounting an optical guide member on a backlight unit and a backlight unit using the same.

Liquid crystal display (LCD) is one of the image display mechanisms, and has an advantage of realizing light weight, thinness and low power consumption compared to other image display apparatuses, CRT.

Due to these advantages, liquid crystal displays have been used for terminals or video devices of various information devices in place of CRT, and in recent years, it is possible to prevent color shifts while securing a wide viewing angle, thereby achieving high quality that can compete with CALTI. Achieving.

In addition, unlike LCD, since the LCD does not emit light by itself, a separate light source is required. Accordingly, the LCD may include a lamp, which is a substantially light source, in addition to the liquid crystal panel that is a display component. It consists of a light guide plate and several optical sheets, and fluorescent lamps using mercury (Hg) are currently used as the lamp.

On the other hand, since most of the liquid crystal display devices are light-receiving elements that display an image by controlling the amount of light source coming from the outside, a separate light source, that is, a backlight, for irradiating light to the liquid crystal panel is necessary, and such backlight is a lamp It is divided into edge type and direct type according to the location where the unit is installed.

In the double-edge method, the lamp unit is installed on the side of the light guide plate for guiding the light, and the lamp unit surrounds the outer surface of the lamp and a lamp holder inserted into both ends of the lamp to protect the lamp and the lamp. It is provided with a lamp reflector that is fitted to the side of the light guide plate to reflect the light emitted from the lamp toward the light guide plate.

The edge method in which the lamp unit is installed on the side of the light guide plate is applied to a relatively small liquid crystal display device such as a monitor of a laptop computer and a desktop computer, and has good light uniformity and a long service life. It is advantageous to thin the liquid crystal display device.

However, the edge method and the direct method use a fluorescent lamp as a light source. Recently, a new light source has been developed in consideration of environmental pollution problems due to the harmfulness of gas entering the fluorescent lamp.

Among them, light emitting diodes (LEDs) have no environmental pollution, are capable of expressing a variety of colors, and can reduce power consumption, and thus are in the spotlight as new materials.

In this regard, the light emitting device array and the backlight unit using the light emitting device according to the related art using the light emitting device (LED) will be described with reference to FIGS. 1 and 2 as follows.

1 is a cross-sectional view showing an edge-type backlight unit according to the prior art.

2 is a plan view illustrating an edge-type backlight unit according to the related art, and illustrates a layout structure of a light emitting device array and a light guide plate.

As shown in FIG. 1, the backlight unit according to the related art includes a light emitting element 11, a light guide plate 13, a light reflector 15, a reflecting plate 17, a diffusion sheet 19, a prism sheet 21, and Protective sheet 23 and the like.

Here, the light emitting element 11 is used as a light source instead of the fluorescent lamp to irradiate light onto the liquid crystal panel 31, and the light generated by the light emitting element 11 is projected onto the liquid crystal element surface through the light guide plate 13. .

In addition, in order to project more light generated by the light emitting element 11 to the light guide plate 13, the light reflector 15 reflecting the light generated by the light emitting element 11 toward the light guide plate 13 is provided as a light emitting element ( 11) Place it around. Here, the light reflector 15 serves as a reflection sheet at the same time.

A light reflector 17 is disposed at a lower end of the light guide plate 13 to reflect light toward the liquid crystal panel 31, and a diffusion sheet 19, a prism sheet 21, and a protective sheet are disposed on an upper end of the light guide plate 13. 23 are arranged one by one.

The backlight unit configured as described above is fixed by the mold frame 25, and an array substrate 10 having a plurality of light emitting elements 11 mounted thereon is disposed at a lower end of the diffusion sheet 19, and is disposed outside the backlight unit. Top case 29 is wrapped.

As described above, in the backlight unit according to the related art, a backlight having a shape in which a plurality of light emitting elements 11 are arranged in a line is used together with the light guide plate 13.

However, the backlight unit to which the light emitting device according to the related art is applied has the following problems.

Since one light emitting element 11 is a point light source in the form of a package that emits light at a constant directivity, when a plurality of light emitting elements are arranged in a row, between the light emitting elements and the next light emitting element, as shown in FIG. 2. The dark portion A does not reach the emitted light.

The dark portion A can be alleviated to some extent when the light emitting device is densely arranged, but the bright spot is clearly distinguished from the center point of the relatively bright light emitting device and the dark portion where the light does not reach. ) And bright lines appear, which is a big problem in backlights requiring uniform brightness.

In particular, in the case of a light emitting diode (LED), a hot spot phenomenon occurs in which the light emitting part is bright in two or more arrangement structures due to the characteristics of the point light source itself. This greatly reduces the screen quality and luminance uniformity in a backlight requiring a uniform surface light source.

Accordingly, the present invention has been made to solve the above problems according to the prior art, a light emitting device array and a backlight unit using the same to improve the uniformity and screen quality of the brightness by removing the bright spot and the dark portion through the light guide member In providing.

Light emitting device array according to the present invention for achieving the above object is a plurality of light emitting devices arranged in at least one column at a predetermined interval from each other; And an optical guide member disposed at a position adjacent to the plurality of light emitting elements and controlling a traveling direction of light emitted from the light emitting elements.

A backlight unit using a light emitting device array according to the present invention for achieving the above object comprises a plurality of light emitting devices arranged in at least one column at a predetermined interval from each other; An optical guide member disposed at a position adjacent to the plurality of light emitting elements and controlling a traveling direction of light emitted from the light emitting elements; A light guide plate disposed on one side of the light guide member; An optical sheet disposed on the light guide plate; An array substrate on which the light emitting element, the light guide member and the light guide plate are mounted; And a mold frame for fixing the light emitting element, the light guide member, and the light guide plate.

Hereinafter, a light emitting device array and a backlight unit using the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view illustrating a backlight unit according to an exemplary embodiment of the present invention, in which a light guide member is disposed between a light emitting device array and a light guide plate.

4 is a plan view illustrating a backlight unit according to an exemplary embodiment of the present invention, in which a light guide member is disposed between a light emitting element array and a light guide plate.

5 is a plan view of the light guide member provided in the backlight unit according to an embodiment of the present invention.

6 is a front view of the light guide member provided in the backlight unit according to an embodiment of the present invention.

As shown in FIG. 3, the backlight unit according to an embodiment of the present invention includes a light emitting device array 100, a light guide member 121, and a light guide plate having a plurality of light emitting devices 101 disposed at a predetermined interval. 103, a light reflector 115, a reflecting plate 117, a diffusion sheet 109, a prism sheet 111, a protective sheet 113 and the like.

In addition, the light emitting device 101 is used as a light source instead of a fluorescent lamp to irradiate light onto the liquid crystal panel 131, and in order to project more light generated by the light emitting device 101 onto the light guide plate 103. A light reflector 105 for reflecting light generated from the light emitting element 101 toward the light guide plate 103 is disposed around the light emitting element 101. Here, the light reflector 105 serves as a reflection sheet at the same time.

The light reflector 107 is disposed at the lower end of the light guide plate 103 to reflect light toward the liquid crystal panel 131, and the diffusion sheet 109, the prism sheet 111, and the protective sheet are disposed on the upper end of the light guide plate 103. 113 are arranged one by one.

The backlight unit configured as described above is fixed by the mold frame 115, and the array substrate 117 on which the light emitting device array 100 having a plurality of light emitting devices is mounted is disposed at the bottom of the light guide plate 103, The top case 119 is wrapped around the backlight unit.

In addition, as illustrated in FIG. 4, a plate for inducing light emitted from the light emitting device between the light emitting device array 100 and the light guide plate 103 having a plurality of light emitting devices 101 arranged in a line. The light guide member 121 having the partition walls 123 having a shape is disposed.

Here, as shown in FIGS. 5 and 6, the optical guide member 121 includes a lower plate 121a and an upper plate 121b spaced apart by a predetermined interval, and the lower plate 121a and the upper plate 121b. It is composed of a plurality of partition wall 123 of the valve form disposed spaced apart at regular intervals therebetween.

In this case, the light guide member 121 is formed of a material having excellent reflection characteristics. In addition, the light emitted from the light emitting device 101 is spread through the plurality of partitions 123 to the area where the light is not propagated by the light is guided in a predetermined direction.

In particular, the orientation angle of the light emitting device 101 has a range of about ± 55 ° to 60 ° with respect to the direction of light propagation by the light guide member 121 having a plurality of partitions 123, At the above angle, no light is emitted.

The plurality of partitions 123 are inclined at different angles with respect to the traveling direction of the light, have a reflective property, and induce light emitted from the light emitting device at an angle greater than the direction angle, so that dark portions and bright spots are generated. Problems can be prevented.

In addition, it is possible to inject uniformly uniform light to the light incident part, which is advantageous to maintain the brightness uniformity.

In addition, the light guide member 121 may be used to change a line array of light emitting devices (LEDs) having point light source characteristics into a line light source such as a lamp.

By forming a linear light source using a combination of point light sources, various conventional optical concepts such as a light guide plate and a prism structure designed based on a lamp currently used as a backlight light source can be similarly applied to a light emitting device (LED).

Meanwhile, a light emitting device array and a backlight unit using the same according to another embodiment of the present invention will be described with reference to FIG. 7.

7 is a cross-sectional view illustrating a backlight unit according to another exemplary embodiment of the present invention, in which a plurality of light emitting devices are mounted on side surfaces of a light emitting device array.

The backlight unit according to another embodiment of the present invention has a structure substantially the same as that of the embodiment of the present invention illustrated in FIG. 3, and a plurality of light emitting devices are arranged at regular intervals on the side surface of the light emitting device array. It is different from one embodiment of the invention. That is, in the case of the temporary embodiment of the present invention, as shown in FIG. 3, the light emitting part of the light emitting element 101 is disposed to face the light reflector 105. However, in another embodiment of the present invention, FIG. As described above, the light exit portion of the light emitting element 201 is disposed so as to face the light guide member 221.

A backlight unit according to another embodiment of the present invention will be described in more detail below.

As shown in FIG. 7, the backlight unit according to another embodiment of the present invention may include a light emitting device 201, a light guide member 221, a light guide plate 203, a light reflector 205, a reflector 207, The diffusion sheet 209, the prism sheet 211, the protective sheet 213, and the like.

In addition, a light emitting device 201 is used as a light source instead of a fluorescent lamp to irradiate light onto the liquid crystal panel 231, and emits light to project more light generated by the light emitting device 201 onto the light guide plate 203. A light reflector 205 that reflects light generated by the device 201 toward the light guide plate 203 is disposed around the light emitting device 201. Here, the light reflector 205 simultaneously serves as a reflective sheet.

In addition, a reflecting plate 207 is disposed at the lower end of the light guide plate 203 to reflect light toward the liquid crystal panel 231, and a diffusion sheet 209, a prism sheet 211, and a protective sheet are disposed on the upper end of the light guide plate 203. 213 are arranged one by one.

The backlight unit configured as described above is fixed by the mold frame 215, the array substrate 217 is mounted with a light emitting device array 221 is provided with a plurality of light emitting devices 201 on the bottom of the diffusion sheet 209. The top case 219 is disposed outside the backlight unit.

In addition, as shown in FIG. 7, a plurality of light emitting devices 201 arranged at least in a line on the side surface portion of the light emitting device array 221 are disposed to face the light guide plate 203, and the plurality of light emitting devices ( Between the 201 and the light guide plate 203, a light guide member 221 is provided with barrier ribs 223 in the form of a plate for guiding light emitted from the light emitting device 201.

Here, the optical guide member 221, as shown in Figures 5 and 6 which is an embodiment of the present invention, the lower plate (not shown) and the upper plate (not shown) and spaced apart by a predetermined interval, and these lower plate (not shown) And a plurality of barrier ribs 223 in the form of valves, which are spaced apart from each other by a predetermined interval.

At this time, the light emitted from the light emitting device 201 is spread through the plurality of partitions 223 to a region where the light is not propagated by the light is guided in a predetermined direction.

In particular, the orientation angle of the light emitting device 201 has a range of about ± 55 ° to 60 ° with respect to the direction of light propagation by the light guide member 221 having a plurality of partitions 223, At the above angle, no light is emitted.

As described above, according to another embodiment of the present invention, the plurality of partition walls provided in the optical guide member are inclined at different angles with respect to the traveling direction of the light, and have a reflective characteristic, and a direction angle. By inducing light emitted from the light emitting device at a larger angle, it is possible to prevent the problem of dark areas and bright spots.

In addition, it is possible to inject uniformly uniform light to the light incident part, which is advantageous to maintain the brightness uniformity.

In addition, the light guide member 221 may be used to change a line array of light emitting devices (LEDs) having point light source characteristics into a line light source such as a lamp.

By forming a linear light source using a combination of point light sources, various conventional optical concepts such as a light guide plate and a prism structure designed based on a lamp currently used as a backlight light source can be similarly applied to a light emitting device (LED).

As described above, the light emitting device array and the backlight unit using the same according to the present invention have the following effects.

The light emitting device array and the backlight unit using the same according to the present invention can remove hot spots by arranging an optical guide member between the light emitting device array and the light guide plate to adjust a directing angle of light emitted from the light emitting device. .

In particular, the light passing through the light guide member reaches the dark portion between the adjacent light emitting elements that the conventionally emitted light did not reach, thereby forming a light source having excellent uniformity without hot spots.

On the other hand, while described above with reference to a preferred embodiment of the present invention, those skilled in the art various modifications of the present invention without departing from the spirit and scope of the invention described in the claims below And can be changed.

Claims (14)

A plurality of light emitting elements arranged in at least one column at regular intervals from each other; And And a light guide member disposed at a position adjacent to the plurality of light emitting devices and controlling a traveling direction of light emitted from the light emitting devices. The light emitting device array according to claim 1, wherein the optical guide member is composed of a plurality of partition walls arranged at a predetermined interval between the lower plate and the upper plate and the upper and lower plates. The light emitting device array of claim 2, wherein the partition wall is formed in a plate shape. The light emitting device array of claim 2, wherein the barrier ribs are inclined at different angles with respect to a traveling direction of light. The light emitting device array of claim 1, wherein the optical guide member is formed of a material having excellent reflection characteristics. The light emitting device array of claim 1, wherein the plurality of light emitting devices are disposed on an upper surface or a side surface of the light emitting device array. The light emitting device array of claim 1, wherein a direction angle of the light emitting device has a range of about ± 55 ° to about 60 ° based on a direction in which light propagates. A plurality of light emitting elements arranged in at least one column at regular intervals from each other; An optical guide member disposed at a position adjacent to the plurality of light emitting elements and controlling a traveling direction of light emitted from the light emitting elements; A light guide plate disposed on one side of the light guide member; An optical sheet disposed on the light guide plate; An array substrate on which the light emitting element, the light guide member and the light guide plate are mounted; And And a mold frame fixing the light emitting element, the light guide member and the light guide plate. The backlight unit of claim 8, wherein the light guide member comprises a plurality of partition walls disposed at a predetermined interval between the lower plate and the upper plate, and the upper and lower plates. The backlight unit of claim 9, wherein the barrier rib is formed in a valve shape. The backlight unit of claim 9, wherein the partition wall is inclined at different angles with respect to a traveling direction of light. The backlight unit of claim 8, wherein the light guide member is formed of a material having excellent reflection characteristics. The backlight unit of claim 8, wherein the plurality of light emitting devices are disposed on an upper surface or a side surface of the light emitting device array. The backlight unit of claim 8, wherein a direction angle of the light emitting device has a range of about ± 55 ° to about 60 ° based on a direction in which light propagates.

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