KR20110051390A - Light emitting diode package, backlight unit and liquid crystal display having the same - Google Patents

Abstract

PURPOSE: A light emitting diode package, a backlight unit and liquid crystal display device having the same are provided to increase light income efficiency while maintaining a constant distance between the light guiding plate and a light source. CONSTITUTION: A light emitting diode package includes a light emitting diode chip(910), a mold unit. The light emitting diode chip generates the light. The mold unit is comprised as the light emitting diode chip for protecting the light emitting diode chip. The mold unit includes a first projection unit(920b).

Description

LIGHT EMITTING DIODE PACKAGE, BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY HAVING THE SAME}

The present invention relates to a light emitting diode package and a backlight unit, and more particularly, to a light emitting diode package capable of increasing light receiving efficiency while maintaining a predetermined distance between the light emitting diode package and the light guide plate, and a backlight unit and a liquid crystal display device having the same.

Cathode ray tube (CRT), which is one of the widely used display devices, is mainly used for monitors such as TVs, measuring devices, and information terminal devices. However, due to the weight and size of the CRT itself, it was not possible to actively cope with the miniaturization and lightening of electronic products.

As a solution to this problem, the liquid crystal display device has a tendency that its application range is gradually widening due to the features such as light weight, thinning, low power consumption driving. Accordingly, in order to meet the needs of users, liquid crystal display devices are progressing in the direction of large area, thinning, and low power consumption.

BACKGROUND ART A liquid crystal display device is a display device that displays an image by controlling an amount of light passing through a liquid crystal, and is widely used for advantages such as thinning and low power consumption.

Unlike the CRT, the liquid crystal display is not a display device that emits light by itself, and thus, a backlight unit including a separate light source is provided on the back of the liquid crystal display panel to provide light for visually representing an image.

The backlight unit has two types, a direct method and an edge method, depending on the position of the light source.

In the edge method, a light source is disposed on a side of a flat plate, and the light emitted from the light source is irradiated onto the entire surface of the liquid crystal display panel using a light guide plate. On the other hand, in the direct method, a plurality of light sources are disposed on the back of the liquid crystal display panel to directly irradiate light directly under the liquid crystal display panel, so that the luminance can be increased by a plurality of light sources compared to the edge method, and the light emitting surface is wider. There is an advantage to this.

Particularly, in the edge type backlight unit, the closer the distance between the light guide plate and the light source is, the better the light guide plate light receiving surface efficiency is, but the light efficiency is increased. Is brought about. In order to solve this reliability problem, it must be designed to maintain a constant distance between the light guide plate and the light source. However, in the case of maintaining a constant distance, a problem arises due to the reduction of the light receiving efficiency due to the increase in the light distance and the light leakage phenomenon.

One object of the present invention is to provide a light emitting diode package, a backlight unit and a liquid crystal display device having the same, which can increase light receiving efficiency while maintaining a constant distance between the light guide plate and the light source. In addition, the thickness of the light guide plate may be reduced by changing the shape of the LED package.

According to an embodiment, a light emitting diode package may include a light emitting diode chip that generates light; And a mold part formed to surround the light emitting diode chip to protect the light emitting diode chip, wherein the mold part is formed to extend from the body and the body on which the light emitting diode chip is mounted, and has an inclined outer surface. It characterized in that it comprises a protrusion.

In another embodiment, the backlight unit may include a light guide plate; And a light emitting diode package disposed on a side surface of the light guide plate, wherein the light emitting diode package includes a light emitting diode chip generating light and a mold part formed to surround the light emitting diode chip to protect the light emitting diode chip. The mold part may include a body on which the light emitting diode chip is mounted and a first protrusion formed extending from the body and having an inclined outer surface.

In another embodiment, the liquid crystal display includes a light guide plate; A light emitting diode package disposed on a side of the light guide plate; And a liquid crystal panel disposed on the light guide plate to display an image, wherein the light emitting diode package includes a light emitting diode chip that generates light and a mold part that surrounds the light emitting diode chip to protect the light emitting diode chip. The mold unit may include a body on which the light emitting diode chip is mounted and a first protrusion formed extending from the body and having an inclined outer surface.

One embodiment has the effect of increasing the light receiving efficiency while maintaining a constant distance between the light guide plate and the light source in order to prevent the deformation caused by heat in the light guide plate as the distance between the light guide plate and the light source closer.

In one embodiment, the light guide plate may have irregularities and protrusions, thereby improving light incident efficiency and preventing light leakage.

In addition, one embodiment has the effect of reducing the thickness of the light guide plate by changing the shape of the LED package.

In the description of the embodiments, each panel, face, sheet, plate, or substrate is described as being formed "on" or "under" of each panel, face, sheet, plate, or substrate, and the like. In the case, “on” and “under” include both being formed “directly” or “indirectly” through other components. In addition, the criteria for the top, side or bottom of each component will be described with reference to the drawings. The size of each component in the drawings may be exaggerated for the purpose of description, it does not mean that the size is actually applied.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view illustrating a liquid crystal display device having a light emitting diode package and a backlight unit according to an exemplary embodiment. 2 is an enlarged view of a light emitting diode package mounted on a printed circuit board according to an embodiment. 3 is a cross-sectional view of a light emitting diode package mounted on the printed circuit board of FIG. 2. 4 is a cross-sectional view of the liquid crystal display taken along the line II ′ of FIG. 1.

Referring to FIG. 1, a liquid crystal display according to an exemplary embodiment includes a liquid crystal display panel 100 displaying an image and a backlight unit 200 disposed under the liquid crystal display panel 100 to provide light. .

Although not shown in detail, the liquid crystal display panel 100 is bonded to a thin film transistor (TFT) substrate, a color filter substrate, and a liquid crystal layer interposed between the two substrates to maintain a uniform cell gap facing each other. It includes. In the thin film transistor substrate, a plurality of gate lines are formed, a plurality of data lines intersecting the plurality of gate lines are formed, and a thin film transistor TFT is formed at an intersection area of the gate line and the data line. The liquid crystal display panel 100 displays an image by using light provided from the backlight unit 200.

The backlight unit 200 is disposed in parallel with the light source 900, the light source housing 700 surrounding the light source 900, and the light source 900 to convert light incident from the light source 700 into surface light. ).

The backlight unit 200 is disposed on the light guide plate 400 to collect and diffuse the light, and to be disposed below the light guide plate 400 to receive light traveling in a downward direction of the light guide plate 400. It further includes a reflective sheet 500 to reduce the light loss by reflecting toward the liquid crystal display panel 100. In addition, the backlight unit 200 further includes a bottom cover 600 made of a metal material having an upper surface thereof coupled to the support main (not shown).

The light source 900 is disposed at the side of the light guide plate 400. In addition, the light source 900 may be a cold cathode fluorescent lamp (CCFL) having an electrode inside both ends of the glass tube, an external electrode fluorescent lamp (EEFL) having a structure surrounding both ends of the glass tube. In addition, the light source 900 may be a light emitting diode (LED) in addition to a lamp.

The light source housing 700 increases the efficiency of the light irradiated from the light source 900 and prevents the loss of light. In addition, the light source housing 700 protects the light source 900.

The light guide plate 400 may be made of polymethyl methacrylate (PMMA). In addition, although not shown in detail in the drawings, the light source 900 may be formed in a wedge shape that becomes thinner away from the incident surface disposed. A prism pattern may be formed on the rear surface of the light guide plate 400 to refracted incident light toward the optical sheets 300.

The light guide plate 400 converts linear or pointed light into surface light and guides the light incident from the light source 900 toward the liquid crystal display panel 100.

The reflective sheet 500 is disposed on the lower surface of the light guide plate 400. The reflective sheet 500, when the light incident on the light guide plate 400 is emitted to the lower portion of the light guide plate 400, the light emitted downward toward the light guide plate 400 and the optical sheets 300. Reflect. The reflective sheet 500 may be made of a material such as PET having a high reflectance.

The optical sheets 300 include a diffusion sheet for diffusing light, a light collecting sheet for condensing light, and a protective sheet for protecting the light collecting sheet. The diffusion sheet, the light collecting sheet, and the protective sheet are sequentially disposed on the light guide plate 400.

The bottom cover 600 has a structure in which an upper surface thereof is opened. The bottom cover 600 protects the backlight unit 200. The bottom cover 600 is formed of a metal material to serve to reinforce the firmness of the backlight unit 200.

2 and 3, a light emitting diode package 900 according to an embodiment includes a light emitting diode chip 910 for generating light and a mold 920 surrounding the light emitting diode chip 910. . The light emitting diode package 900 is mounted on the printed circuit board 800. The printed circuit board 800 may be made of any one material of nonmetallic and metallic.

The light emitting diode package 900 may be disposed by a combination of red (R), green (G) and blue (B) light emitting diodes, and the red (R), green (G), blue (B) and white (W) may be arranged in combination of the light emitting diodes. In the present invention, the light emitting diode package 900 is configured to include a light emitting diode chip 910 for generating blue (B) light and a yellow phosphor to excite the blue (B) light to implement white (W) light. do. That is, the LED package 900 may further include a yellow phosphor material (not shown) that excites the blue (B) light generated by the LED chip 910 to implement the white (W) light. have.

The mold part 920 is manufactured using a rigid polymer resin to protect the light emitting diode chip 910. The mold part 920 may be manufactured using, for example, poly phasal amide (PPA), but the material of the mold part 920 is not limited thereto.

In one embodiment, the mold portion 920 is formed of a body 920a on which the light emitting diode chip 910 is mounted and a first protrusion 920b extending from the body 920a and having an inclined outer surface. It includes.

When the mold part 920 is formed, the body 920a and the first protrusion 920b may be integrally formed.

The first protrusion 920b guides the light generated from the light emitting diode chip 910 to enter the incident surface 420 of the light guide plate 400. In addition, the first protrusion 920b may not be incident to the light guide plate 400 and may effectively prevent light leaking.

The outer surface of the first protrusion 920b may be inclined, and the shape is not limited as long as the guide and the light leakage prevention effect can be exhibited. In addition, due to the shape of the first protrusion 920b, since the light generated from the light emitting diode chip 910 may be effectively incident on the light guide plate 400, the thickness of the light guide plate 400 may be reduced.

Therefore, even if the distance between the light guide plate 400 and the light emitting diode package 900 is about 2 mm in order to increase the light receiving efficiency, the light receiving efficiency is increased by about 55% or more than when the same distance is maintained (FIG. 6). That is, the amount of light incident on the light increases from about 400 lux to about 650 lux. In addition, since the distance between the light guide plate 400 and the light emitting diode package 900 is maintained at 2 mm, heat deformation does not occur in the light guide plate 400.

In one embodiment, a reflective sheet 930 for reflecting light may be attached to an inner surface of the first protrusion 920b. Due to the reflective sheet 930, even if the light generated from the LED chip 910 reaches the first protrusion 920b, the light guide plate 400 may guide the light more effectively.

In an embodiment, the backlight unit 200 may form a second protrusion 410 on the light guide plate 400 to correspond to the first protrusion 920b of the LED package 900. For example, an outer surface of the first protrusion 920b and an inner surface of the second protrusion 410 may be formed in parallel with each other. The second protrusion 410 may prevent the light generated from the light emitting diode chip 910 from leaking without being incident on the light guide plate 400.

That is, the light generated from the light emitting diode chip 910 is guided by the first protrusion 920b and is incident on the incident surface 420 of the light guide plate 400, and the incident surface 420 of the light guide plate 400. Light leaking without reaching may be prevented by the first protrusion 920b and the second protrusion 410. Therefore, the light efficiency of the light emitted from the light emitting diode chip 910 is incident on the light guide plate 400 may be improved.

In another embodiment, a diffusion pattern or an uneven portion may be formed on the incident surface 420 of the light guide plate 400. In order to effectively enter the light generated from the light emitting diode chip 910 into the light guide plate 400, a diffusion pattern or an uneven portion may be formed on the incident surface 420 of the light guide plate 400. Therefore, the light efficiency incident on the light guide plate 400 may be improved.

In FIG. 5, the light incidence efficiency improvement rate according to the distance between the light guide plate and the light emitting diode is shown. That is, the closer the distance between the light guide plate and the light emitting diode is, the better the light receiving efficiency is. However, if the distance is too close due to the characteristics of the light guide plate, the light guide plate may be deformed by heat. Therefore, the light guide plate should be kept at a certain distance so as not to be deformed by heat.

In one embodiment, the first protrusion is formed in the mold portion of the LED package as described above to improve the light receiving efficiency while maintaining the distance between the LED package and the light guide plate at about 2 mm without causing the light guide plate to be deformed by heat. And a second protrusion or the like on the light guide plate.

Therefore, even if the distance between the light guide plate 400 and the light emitting diode package 900 is about 2 mm in order to increase the light receiving efficiency, the light receiving efficiency is increased by about 55% or more than when maintaining the same distance. That is, the amount of incident light increases from about 400 lux to about 650 lux (FIG. 6). In addition, since the distance between the light guide plate 400 and the light emitting diode package 900 is maintained at 2 mm, heat deformation does not occur in the light guide plate 400.

Although the above description has been made with reference to the embodiments, these are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains are not illustrated above without departing from the essential characteristics of the present embodiments. It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment.

2 is an enlarged view of a light emitting diode package mounted on a printed circuit board according to an embodiment.

3 is a cross-sectional view of a light emitting diode package mounted on the printed circuit board of FIG. 2.

4 is a cross-sectional view of the liquid crystal display taken along the line II ′ of FIG. 1.

5 shows an improvement in light incidence efficiency according to a distance between a light emitting diode and a light guide plate.

Figure 6 shows the light incidence efficiency of the invention according to the prior art and one embodiment at the same distance of 2 mm.

Claims (8)

A light emitting diode chip for generating light; It includes a mold formed in a form surrounding the light emitting diode chip to protect the light emitting diode chip, The mold unit includes a body on which the light emitting diode chip is mounted and a first protrusion formed extending from the body and having an inclined outer surface. The method of claim 1, The inner surface of the first protrusion portion is a light emitting diode package, characterized in that a reflective sheet for reflecting light is attached. The method of claim 1, The light emitting diode package, characterized in that the body and the first protrusion is formed integrally. Light guide plate; And It includes a light emitting diode package disposed on the side of the light guide plate, The light emitting diode package includes a light emitting diode chip for generating light and a mold part formed to surround the light emitting diode chip to protect the light emitting diode chip. The mold unit includes a body on which the light emitting diode chip is mounted and a first protrusion formed extending from the body and having an inclined outer surface. The method of claim 4, wherein And a second protrusion formed on a side surface of the light guide plate to correspond to the first protrusion. The method of claim 5, And an outer surface of the first protrusion and an inner surface of the second protrusion are parallel to each other. The method of claim 4, wherein The backlight unit, characterized in that a plurality of diffusion patterns or irregularities formed on the incident surface of the light guide plate. Light guide plate; A light emitting diode package disposed on a side of the light guide plate; And A liquid crystal panel disposed on the light guide plate to display an image; The light emitting diode package includes a light emitting diode chip for generating light and a mold part formed to surround the light emitting diode chip to protect the light emitting diode chip. The mold unit includes a body on which the light emitting diode chip is mounted and a first protrusion formed extending from the body and having an inclined outer surface.

Images