KR101679077B1 - Backlgiht unit and liquid crystal display device the same - Google Patents

Abstract

The present invention discloses a backlight unit having a structure capable of maximizing heat dissipation efficiency.
The backlight unit of the present invention is fixed to the inner surface of the bottom cover and includes a heat dissipating plate which penetrates a receiving hole formed in the bottom cover and is exposed at the bottom of the bottom cover to dissipate heat from the light source unit.

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE THE SAME [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and more particularly, to a backlight unit having a structure capable of maximizing heat dissipation efficiency and a liquid crystal display device having the same.

A CRT (cathode ray tube), which is one of the widely used display devices, is mainly used for monitors such as a TV, a measurement device, and an information terminal device. However, due to the weight and size of the CRT itself, Could not respond positively to the response of

As a solution to such a problem, the liquid crystal display device has been gradually widened due to its features such as lightness, thinness, and low power consumption driving. Accordingly, the liquid crystal display device is proceeding in the direction of large-sized, thin, and low power consumption in response to the demand of the user.

2. Description of the Related Art [0002] A liquid crystal display device is a display device that displays an image by adjusting the amount of light transmitted through a liquid crystal, and is widely used because of its advantages such as thinness and low power consumption.

Unlike a CRT, the liquid crystal display device is not a self-luminous display device. Therefore, a backlight unit including a separate light source for providing light for visually expressing an image is provided on a back surface of the liquid crystal display panel.

There are two types of the backlight unit, that is, a direct method and an edge method, depending on the position of a light source.

In the edge system, a light source is disposed on a side surface of a flat plate, and light emitted from a light source is irradiated to the entire surface of the liquid crystal display panel using a light guide plate. On the other hand, in the direct-type method, a plurality of light sources are arranged on the back surface of a liquid crystal display panel and light is directly irradiated right under the liquid crystal display panel. In comparison with the edge method, brightness can be increased by a plurality of light sources, There is an advantage to be able to do.

The liquid crystal display panel has a structure in which the thin film transistor substrate and the color filter substrate are arranged so as to face each other. The thin film transistor substrate and the color filter substrate are bonded together by a seal pattern, and liquid crystal is injected therebetween.

Since the liquid crystal display device is not a self-luminous display device, a backlight unit for providing light to the lower portion of the liquid crystal display panel on which an image is displayed is provided.

The backlight unit is divided into an edge type and a direct type according to the manner in which the light sources are arranged.

The edge type backlight unit is composed of a light source provided on a side surface and a light guide plate for scattering the light incident from the light source, and is advantageous for thinning and is mainly used in small and medium sized liquid crystal display devices.

The direct-type backlight unit has a structure in which a plurality of light sources are disposed at a predetermined interval at a lower portion of a liquid crystal display panel to directly irradiate light directly under the liquid crystal display panel, and is mainly used in a large-screen liquid crystal display device.

The backlight unit is provided with a lamp or a light emitting diode (LED) as a light source. 2. Description of the Related Art In recent years, light emitting diodes that are advantageous for low power consumption and slimness have been used.

The light emitting diode has a long life, can be reduced in size and weight, has strong light directivity, and can be driven at a low voltage. In addition, it is strong against impact and vibration, and it is expected to replace incandescent lamp, fluorescent lamp, mercury lamp and conventional white light source in the next few years because it can be packaged in various forms without preheating time and complicated driving circuit. Particularly, light emitting diodes have been attracting much attention because they have high energy band gap and thus are capable of outputting light in a short wavelength range from red to ultraviolet rays, and are excellent in physical / chemical stability, thereby realizing high efficiency and high output .

The light emitting diode has a problem that the lifetime thereof is lowered due to heat generated at the time of driving, or the amount of light is uneven. In recent years, a structure has been proposed in which a bottom cover made of a metal and a printed circuit board on which a light emitting diode is mounted are designed to be in direct contact with each other and a contact area is increased in order to improve the defect caused by heat of the light emitting diode. However, There was a problem.

An object of the present invention is to provide a backlight unit having a structure capable of maximizing the heat dissipation efficiency and a liquid crystal display device having the backlight unit.

A backlight unit according to an embodiment of the present invention includes a light source unit including a plurality of light emitting diodes, a bottom cover accommodating the light source unit and having an open upper surface, a reflective sheet housed on the bottom cover, A support portion extending from the side portion and supporting one side lower surface of the reflection sheet, and a support portion extending from the support portion and penetrating through the receiving hole formed in the bottom cover, the lower surface of the bottom cover And a heat radiating plate including a contact portion which is exposed externally and which is in contact with a lower surface of the bottom cover.

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The liquid crystal display device of the present invention comprises a liquid crystal display panel, a light source unit including a plurality of light emitting diodes for providing light to the liquid crystal display panel, a bottom cover in which the light source unit is housed and whose upper surface is open, A cover member which is fixed to the inner surface of the bottom cover and which is accommodated on the cover and which is extended from the side surface portion of the light source unit to face the printed circuit board and a supporting portion for supporting one lower surface of the reflective sheet, And a contact portion which is exposed through an outer surface of the lower surface of the bottom cover and contacts the lower surface of the bottom cover.

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The liquid crystal display device according to an embodiment of the present invention includes a heat dissipation plate for dissipating heat of a light source unit provided on an inner surface of a bottom cover, a side surface portion of the heat dissipation plate is fixed to a light source unit, Hole is penetrated through the hole and is fixed to the bottom surface of the bottom cover and exposed to the bottom of the bottom cover, thereby maximizing the heat dissipation effect.

Further, the liquid crystal display of the present invention has an advantage that the heat radiating plate is exposed from the outside by the structure of the contact portion of the heat radiating plate passing through the receiving hole of the bottom cover, and the heat radiating effect by convective phenomenon can be improved.

Therefore, the present invention has an advantage that the lifetime of the light emitting diode is reduced due to heat generated from the light emitting diode, and the problem that the amount of light is uneven is improved, thereby improving the reliability of the liquid crystal display device.

1 is an exploded perspective view illustrating a liquid crystal display device according to an embodiment of the present invention.
2 is a cross-sectional view illustrating a liquid crystal display device cut along a line I-I 'in FIG.
3 is a perspective view showing the heat dissipation plate of the present invention.
4 is a perspective view showing the assembly of the heat radiating plate and the bottom cover of the present invention.

The present invention relates to a light source unit comprising a light source unit including a plurality of light emitting diodes, a bottom cover accommodating the light source unit and having an open upper surface, a reflective sheet accommodated on the bottom cover, And a heat generating plate which penetrates the receiving hole and is exposed at an outer periphery of the lower surface of the bottom cover to dissipate heat from the light source unit.

The heat dissipation plate includes a side surface facing the printed circuit board of the light source unit, a support portion extending from the side surface portion to support one side lower surface of the reflective sheet, and a support portion extending from the support portion to contact the lower surface of the bottom cover, And a contact portion which is formed on the base portion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, embodiments of the present invention will be described in detail.

FIG. 1 is an exploded perspective view illustrating a liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating a liquid crystal display device cut along a line I-I 'of FIG.

FIG. 3 is a perspective view illustrating the heat dissipating plate of the present invention, and FIG. 4 is a perspective view illustrating assembly of the heat dissipating plate and the bottom cover of the present invention.

1 to 4, a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal display panel 110 on which an image is displayed, a liquid crystal display panel 110 disposed below the liquid crystal display panel 110, The backlight unit 120 includes a backlight unit (not shown).

The liquid crystal display of the present invention further includes a panel guide 118 for supporting the lower edge of the liquid crystal display panel 110 and a top case 100 for covering the upper edge of the liquid crystal display panel 110 .

The liquid crystal display panel 110 includes a thin film transistor substrate 111, a color filter substrate 112, and a liquid crystal layer sandwiched between the two substrates so as to maintain a uniform cell gap.

Although not shown in detail in the drawing, the thin film transistor substrate 111 and the color filter substrate 112 will be described in detail. In the thin film transistor substrate 111, a plurality of gate lines and data lines intersect to define pixels, A thin film transistor (TFT) is provided for each intersecting region of the pixels and connected in one-to-one correspondence with the pixel electrodes mounted on the respective pixels. The color filter substrate 112 includes color filters of R, G, and B colors corresponding to the respective pixels, a black matrix for covering the gate lines, the data lines, the thin film transistors, etc., .

A driving PCB 115 for supplying a driving signal to the gate line and the data line is provided at the edge of the liquid crystal display panel 110.

The driving PCB 115 is electrically connected to the liquid crystal display panel 110 by a chip on film (COF) 117. Here, the COF 117 may be changed to a TCP (Tape Carrier Package).

A backlight unit 120 disposed at a lower portion of the liquid crystal display panel 110 includes a bottom cover 190 having an opened upper surface and a light source unit 150 disposed on an inner surface of the bottom cover 190 to emit light, A light guide plate 140 disposed in parallel with the light source unit 150 and converting the light or light into a light plane and a light guide plate 140 disposed below the light guide plate 140 to guide the light traveling to the lower portion of the light guide plate 140 to the liquid crystal display panel 110 And an optical sheet 130 disposed on the light guide plate 140 and diffusing and condensing the light emitted from the light guide plate 140. [

The light source unit 150 includes a printed circuit board 151 and a plurality of light emitting diodes 153 disposed on the printed circuit board 151 with a predetermined interval therebetween. Here, the printed circuit board 151 may be made of a metal PCB having excellent thermal conductivity.

The backlight unit 120 of the present invention is in contact with the light source unit 150 and the bottom cover 190 to conduct the heat generated from the light source unit 150 to the bottom cover 190, .

That is, the heat dissipating plate 180 has a function of dissipating heat generated from the light source unit 150.

The heat dissipating plate 180 includes a side surface portion 181 facing the printed circuit board 151, a support portion 183 extending from the side surface portion 181 and supporting one side lower surface of the reflective sheet 170, And a contact portion 185 extending from the bottom cover 190 and contacting the bottom surface of the bottom cover 190.

A thermally conductive pad 155 is attached to the inner surface of the side portion 181 and the thermally conductive pad 155 has a function of bonding the side surface portion 181 to the printed circuit board 151.

The outer side and the lower side of the side portion 181 are in surface contact with the inner side surfaces of the top case 100 and the bottom cover 190 made of a metal.

One surface of the heat conductive pad 155 is in surface contact with the inner surface of the side surface portion 181 and the other surface of the heat conductive pad 155 is in surface contact with one surface of the printed circuit board 151.

The support portion 183 has a structure in which the first and second bending portions 183a and 183b are bent in the direction of the reflection sheet 170.

That is, the support portion 183 is extended without breaking so as to correspond to the longitudinal direction of the printed circuit board 151 by the first and second bending portions 183a and 183b bent to both sides so that one edge of the reflection sheet 170 .

The supporting portion 183 is in surface contact with the lower surface of one side of the reflective sheet 170.

The contact portion 185 is bent in a direction parallel to the lower surface of the bottom cover 190 from the support portion 183. [

The lower surface of the contact portion 185 is exposed to the rear surface of the liquid crystal display device.

The bottom cover 190 is formed with a receiving hole 191 to allow the abutting portion 185 to contact the bottom surface of the bottom cover 190.

The receiving hole 191 has a structure corresponding to the longitudinal direction of the contact portion 185 so that the contact portion 185 can pass therethrough.

The contact portion 185 penetrates the receiving hole 191 and contacts the lower surface of the bottom cover 190 adjacent to the receiving hole 191. [

The upper surface of the contact portion 185 is in surface contact with the lower surface of the bottom cover 190 and the lower surface of the contact portion 185 is exposed in the lower direction of the bottom cover 190.

Although not shown in detail in the drawings, a thermal conductive pad may be provided between the contact portion 185 of the present invention and the lower surface of the bottom cover 190.

The heat radiation plate 180 may be exposed from the outside by the receiving hole 191 of the bottom cover 190 and the heat radiating effect due to convection may be improved.

The assembly of the heat dissipation plate 180 and the bottom cover 190 is configured such that the end of the contact portion 185 of the heat dissipating plate 180 penetrates through the bottom cover 190 in the direction of the receiving hole 191.

The contact portion 185 of the heat dissipating plate 180 passes through the receiving hole 191 of the bottom cover 190 and the side surface portion 181 of the heat dissipating plate 180 contacts the inner surface of the bottom cover 190 do.

The liquid crystal display of the present invention is provided with the heat dissipating plate 180 and the contact portion 185 of the heat dissipating plate 180 is connected to the lower surface of the bottom cover 190 through the receiving hole 191 of the bottom cover 190 And has a heat dissipation effect of 3 degrees or more as compared with a general liquid crystal display device.

As described above, the liquid crystal display device according to an embodiment of the present invention includes the heat radiating plate 180 for radiating heat from the light source unit 150 provided on the inner surface of the bottom cover 190, Is fixed to the light source unit 150 and the contact portion 185 penetrates the receiving hole 191 of the bottom cover 190 and is fixed to the lower surface of the bottom cover 190 so that the bottom cover 190 The heat radiation effect can be maximized.

In the liquid crystal display of the present invention, the heat radiating plate 180 is exposed from the outside by the structure of the contact portion 185 of the heat radiating plate 180 passing through the receiving hole 191 of the bottom cover 190, So that the heat radiation effect by the heat sink can be improved.

Accordingly, the present invention has an advantage that the lifetime of the light emitting diode 153 is reduced due to heat generated from the light emitting diode 153, and the problem of nonuniformity of the light amount is improved, thereby improving the reliability of the liquid crystal display device.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

180: heat radiating plate 181:
183: Support part 185: Contact part
190: bottom cover 191: receiving hole

Claims (16)

A light source unit including a plurality of light emitting diodes;
A bottom cover in which the light source unit is housed and whose upper surface is opened;
A reflective sheet housed on the bottom cover; And
A support portion that is fixed to an inner surface of the bottom cover and faces the printed circuit board of the light source unit, a support portion that extends from the side portion and supports one side lower surface of the reflection sheet, And a heat dissipating plate including a contact portion that is exposed through an outer surface of the bottom surface of the bottom cover to contact with a bottom surface of the bottom cover. The method according to claim 1,
Wherein the light source unit is provided on an inner surface of the bottom cover. The method according to claim 1,
And a heat conductive pad for fixing the printed circuit board and the side portion to the inner side surface of the side portion. The method according to claim 1,
Wherein an outer side and a lower side of the side portion are in surface contact with inner surfaces of the bottom cover. The method according to claim 1,
Wherein the support portion has first and second bending portions bent to both sides facing the longitudinal direction of the printed circuit board. The method according to claim 1,
Wherein the contact portion is bent from the support portion in a direction parallel to a lower surface of the bottom cover. The method according to claim 1,
Wherein the contact portion is in surface contact with a lower surface of the bottom cover adjacent to the receiving hole. The method according to claim 1,
And a heat conductive pad is provided between the contact portion and the lower surface of the bottom cover. A liquid crystal display panel;
A light source unit including a plurality of light emitting diodes for providing light to the liquid crystal display panel;
A bottom cover in which the light source unit is housed and whose upper surface is opened;
A reflective sheet housed on the bottom cover; And
A support portion that is fixed to an inner surface of the bottom cover and faces the printed circuit board of the light source unit, a support portion that extends from the side portion and supports one side lower surface of the reflection sheet, And a heat dissipation plate including a contact portion which is exposed through an outer periphery of the lower surface of the bottom cover and penetrates through the receiving hole to be in contact with a lower surface of the bottom cover. 10. The method of claim 9,
Wherein the light source unit is provided on the inner surface of the bottom cover. 10. The method of claim 9,
And a heat conductive pad for fixing the printed circuit board and the side portion to the inner side surface of the side portion. 10. The method of claim 9,
Wherein an outer side and a lower side of the side portion are in surface contact with inner surfaces of the bottom cover. 10. The method of claim 9,
Wherein the support portion has first and second bending portions bent to both sides facing the longitudinal direction of the printed circuit board. 10. The method of claim 9,
Wherein the contact portion is bent in a direction horizontal to the lower surface of the bottom cover from the supporting portion. 10. The method of claim 9,
And the contact portion is in surface contact with a lower surface of the bottom cover adjacent to the receiving hole. 10. The method of claim 9,
And a heat conductive pad is provided between the contact portion and the lower surface of the bottom cover.

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