KR20110135553A - Backlight unit and display device including the same - Google Patents

Abstract

PURPOSE: A backlight unit is provided to improve the heat dissipation. CONSTITUTION: A backlight unit includes a light emitting module(100) and a heat transfer member(220). A light emitting device is prepared in the light emitting module. The heat transfer member emits the heat of the light emitting module. The heat transfer member includes a heat absorbing unit and heat transfer unit. The heat absorbing unit is even with the light emitting module. The heat transfer unit connects the heat emitting unit and the heat absorbing unit.

Description

Backlight unit and display device including the same {Backlight unit and display device including the same}

Embodiments relate to a backlight having a light emitting device and a display device including the same.

Light emitting devices such as light emitting diodes or laser diodes using semiconductors of Group 3-5 or 2-6 compound semiconductor materials of semiconductors have various colors such as red, green, blue and ultraviolet rays due to the development of thin film growth technology and device materials. It is possible to realize efficient white light by using fluorescent materials or combining colors, and it has low power consumption, semi-permanent life, fast response speed, safety and environmental friendliness compared to conventional light sources such as fluorescent and incandescent lamps. Has an advantage.

Therefore, a white light emitting device that can replace a fluorescent light bulb or an incandescent bulb that replaces a Cold Cathode Fluorescence Lamp (CCFL) constituting a backlight of a transmission module of an optical communication means and a liquid crystal display (LCD) display device. Applications are expanding to diode lighting devices, automotive headlights and traffic lights.

The embodiment is to improve the heat dissipation effect of the backlight unit and the display device.

An embodiment includes a module provided with a light emitting element, a heat transfer member for dissipating heat of the module, wherein the heat transfer member includes a heat absorption unit parallel to the light emitting module, a heat release unit, and the heat absorption unit; It provides a backlight unit comprising a heat transfer unit for connecting the heat dissipation unit.

Another embodiment includes a backlight unit including a module including a light emitting element, a reflector and a light guide plate provided on one side of the light source array, and a frame including a heat transfer member for dissipating heat of the module; An optical member for projecting light projected from the backlight to a panel; A panel provided on the optical member to implement an image by projected light; And a color filter provided on the front surface of the panel and selectively transmitting one of red, green, and blue light, wherein the heat transfer member comprises: a heat absorbing part parallel to the light emitting module; Provided is a display apparatus including a heat transfer unit connecting a heat absorption unit and a heat release unit.

Here, the heat transfer member may be a heat pipe having a circular cross section.

The heat pipe may have an elliptical cross section.

The heat transfer part may form an angle of 30 to 60 degrees with the heat absorber.

The heat transfer member may be in contact with the frame and the module.

The heat transfer member may have left and right symmetry with a margin in the center of the frame.

The backlight unit may further include a metal cover fixing the heat transfer member to the frame.

In addition, the metal cover may not be formed in the heat transfer part.

In addition, the metal cover in the heat absorbing portion may be formed to thank a portion of the heat transfer member.

In the backlight unit and the display device according to the embodiment, heat dissipation efficiency is improved.

1 is a view showing an embodiment of a light emitting device,
2 is a cross-sectional view showing an embodiment of a frame provided with a light emitting device module and a heat transfer member;
3 is a view illustrating an embodiment of a heat transfer member of a backlight unit according to an embodiment;
4 is an enlarged view of a portion A of FIG. 3,
Figure 5a is a view showing an embodiment of a cross section of the heat transfer member,
5B is a view showing an embodiment of the side of the heat transfer member,
6a to 6c are views showing other embodiments of the backlight;
7 is a diagram illustrating an embodiment of a display device.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described.

In the description of the above embodiments, each layer (region), region, pattern or structures may be "on" or "under" the substrate, each layer (layer), region, pad or pattern. In the case of what is described as being formed, "on" and "under" include both being formed "directly" or "indirectly" through another layer. In addition, the criteria for the top or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

1 is a view showing an embodiment of a light emitting device.

As shown in FIG. 1, the light emitting device package 100 includes a light emitting device 14 on the package body 20, and includes first and second electrodes 11 and 12 formed on the package body 18. The light emitting element 14 is electrically connected.

The light emitting device 14 may be a light emitting diode having a nitride semiconductor including a p-type semiconductor layer, an active layer, and an n-type semiconductor layer formed on a substrate.

In addition, the light emitting device 14 may be fixed on the package body 20 through the bonding layer 16, and although not shown, a heat radiation pad may be provided to absorb heat emitted from the light emitting device 14. Can be released.

The package body 20 may include a silicon material, a synthetic resin material, or a metal material. An inclined surface may be formed around the light emitting device 100 to increase light extraction efficiency.

The light emitting device 14 may be electrically connected to the first and second electrodes 11 and 12 by any one of a flip chip method and a die bonding method in addition to the wire bonding 15 method.

The first electrode layer 11 and the second electrode layer 12 are electrically separated from each other, and provide power to the light emitting device 100. In addition, the first electrode layer 11 and the second electrode layer 12 may increase the light efficiency by reflecting the light generated from the light emitting device 100, the heat generated from the light emitting device 100 May also act as a drain.

The filler 18 may surround and protect the light emitting device 100. In addition, the filler 18 may include a phosphor to change the wavelength of light emitted from the light emitting device 100.

In addition, a lens 17 is formed, the lens 17 may be provided on the filler 17, surround the filler 17, or formed on the package body 20, the package body 20 may be covered. The lens 17 may change the path of the light emitted from the light emitting diode element 14, and the lens 17 may be omitted.

A light source array is provided at one end of the frame having the above-described structure, and the light source array may include a plurality of light emitting diode packages 100 fixed on a printed circuit board. The same is true for.

2 is a cross-sectional view showing an embodiment of a frame provided with a light emitting module and a heat transfer member.

As illustrated, an array of light emitting device packages 100 is provided on the printed circuit board 110. The printed circuit board 110 having the array of light emitting device packages 100 is bonded to the first surface of the 'b' shaped bracket 120. Hereinafter, this combination of the bracket 120, the printed circuit board 110, and the light emitting device package 120 will be referred to as a light emitting module.

The light emitting module is fixed to one side of the frame 200, and the heat transmitting member 220 is provided on the frame 200 in contact with the bracket 120. In this case, the heat transfer member 220 may be provided in direct contact with the printed circuit board 110.

Here, the frame 200 may be made of a metal having excellent strength, and may be made of stainless, for example, having excellent corrosion resistance. In addition, according to the trend of slimming of the backlight unit, the thickness of the frame 200 may use 0.1 to 0.2 millimeters. In addition, the size of the frame 200 may vary according to the screen size of a display device such as a liquid crystal display device in which a backlight unit is to be used. However, considering the screen of the display device, the frame 200 may be provided in a rectangular shape.

3 is a view illustrating an embodiment of a heat transfer member of a backlight unit according to an embodiment, FIG. 4 is an enlarged view of a portion A of FIG. 3, and FIG. 5A is a view illustrating an embodiment of a cross section of a heat transfer member. 5B is a view showing an embodiment of the side of the heat transfer member. Hereinafter, an embodiment of a heat transfer member and a backlight unit including the same will be described with reference to FIGS. 3 to 5B.

As shown, the heat transfer members 220a, 220b, 220c, 220d, 220a ', 220b', 220c ', 220d', hereinafter referred to as '220' are fixed on the frame 200. In addition, the heat transfer member 220 is provided by directly interviewing the printed circuit board 110 or the bracket 120 provided with the light emitting device 100.

In this case, the heat transfer member 220 emits heat generated from the light emitting module, which is directed from the light emitting device 100 to the opposite direction of the frame 200. The heat transfer member 220 may increase heat dissipation efficiency as the area in contact with the printed circuit board 110 or the bracket 120 increases.

Therefore, as shown in the drawing, the heat transfer member 220 is bent near the light emitting device 100 and has a structure in which a contact area is increased.

That is, as shown in FIG. 4, the heat transfer member 220a includes a heat absorber 220a-c, a heat radiator 220a-a, and a heat transfer unit 220a-b that are parallel to the light emitting module. .

Here, the heat absorber 220a-c absorbs heat generated during light emission of the light emitting device from the printed circuit board 110 or the bracket 120 as described above. The heat transfer part 220a-b transfers the heat absorbed from the heat absorption part 220a-c to the heat release part 220a-a, and the heat release part 220a-a is received. Heat is radiated away from the light emitting module.

And, as shown in Figure 4 is provided with a metal cover 225, to fix the heat transfer member on the frame 200, in particular can be fixed the heat absorbing portion (220a-c). In addition, the metal cover 225 may not fix the entire heat absorbing portion 220a-c.

In addition, a heat pipe may be used as the heat transfer member 220. The heat transfer member 220 may be filled with a medium having excellent thermal conductivity in a pipe-shaped conductive material. 5A, the heat transfer member 220 may have a shape of a heat pipe having an elliptical cross section.

That is, the thickness of the heat transfer member 220 may be provided thin for ultra-thin backlight, and the elliptical heat transfer member 200 may be designed. In addition, as illustrated, the surface of the heat transfer member 220 may form the heat pipe 222 with a material having excellent thermal conductivity such as copper, and a medium 224 may be filled therein.

In FIG. 5B, the configuration of the heat transfer member is shown in detail. Here, the heat dissipating parts 220a-a of the heat transfer member have _a thickness t _{a, but} the thicknesses of other parts may be the same. In addition, the height h _a of the heat dissipating parts 220a-a should be sufficiently provided for heat dissipation, but should be shorter than the height of the frame 200.

The length w _c of the heat absorption parts 220a-c may be sufficiently provided for heat absorption of the light emitting module. In addition, the angle formed by the heat transfer parts 220a-b, that is, the angle θc of the imaginary line extending from the heat absorbing parts 220a-c and the heat dissipating parts 220a-c, respectively, is 30 to 60 degrees. The angle can be achieved.

If the angle is too small, the width of the heat transfer member becomes too large to be detrimental to space utilization, and if the angle is too large, damage at the bent portion of the heat transfer member may occur.

The heat dissipating parts 220a-c are most advantageous for heat dissipation when provided in a direction perpendicular to the light emitting module, but need not be 90 degrees.

When power is supplied to the LED package in the backlight having the above-described structure, heat may be generated on a printed circuit board, etc., and heat may be emitted to the outside of the frame through the heat transfer member. In addition, since the heat transfer member is interviewed with the light emitting module, the contact interview is increased and the heat dissipation efficiency is further increased. And, the elliptical heat transfer member can further increase the contact area with the frame.

6A to 6C show other embodiments of the backlight unit. In the above-described embodiment, the heat transfer member 220 having a symmetrical structure with respect to the center of the frame 200 is provided. However, in the embodiment shown in FIGS. 6A and 6B, the heat transfer member 220 is asymmetrical. Is provided in the same shape. Here, the heat transfer member 220 is indicated by 220a ~ 220h.

In FIG. 6C, the backlight in the two-edge direction is illustrated. That is, the light emitting modules 100 are provided on opposite surfaces of the frame, and at this time, a heat transfer member 220 for dissipating heat corresponding to each light emitting module 100 is provided, and the heat transfer member ( 220 is a symmetrical structure with respect to the center of the frame, the symmetrical structure of the heat transfer member 220 in the left, right, up and down direction as a whole.

That is, 220a, 220b, 220c, and 220d have a symmetrical structure with 220a ', 220b', 220c ', and 220d' in order.

The backlight unit may include a reflector and a light guide plate (not shown). The light guide plate scatters the light emitted from the light emitting device package so that the light is uniformly distributed over the entire screen of the liquid crystal display. In addition, the reflection plate functions to totally reflect the light reflected and lost to the lower portion of the light guide plate into the light guide plate.

In addition, an optical member such as a diffusion plate is provided on the light guide plate to diffuse light emitted from the light guide plate at a predetermined angle.

7 is a diagram illustrating an embodiment of a display device. Hereinafter, a display apparatus according to an embodiment will be described with reference to FIG. 7.

The detailed structure of the frame 310 including the light emitting module and the heat transfer member is as described above. In addition, the reflection plate (not shown) totally reflects the light lost by being reflected to the lower portion of the light guide plate 320 into the light guide plate 320. The reflector may reflect light leaked downward through the bottom of the light guide plate 320 to the upper part of the light guide plate 320 to increase the brightness of the display device and to uniformly emit light toward the liquid crystal display device. . The reflector may be made of a material having high reflectivity and being extremely thin, and may use polyethylene terephtalate (PET).

The light guide plate 320 scatters the light emitted from the light emitting device package so that the light is uniformly distributed over the entire area of the screen of the liquid crystal display. Accordingly, the light guide plate 320 may be formed of a material having good refractive index and high transmittance, and may be formed of polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene (PE), or the like.

An optical member 330 is provided on the light guide plate 320 to diffuse the light emitted from the light guide plate 320 at a predetermined angle. The optical member 330 uniformly irradiates the light guided by the light guide plate 320 in the direction of the panel 340 such as a liquid crystal display.

As the optical member 330, an optical sheet such as a diffusion sheet, a prism sheet, or a protective sheet may be selectively laminated, or a micro lens array may be used. In this case, a plurality of optical sheets may be used, and the optical sheets may be made of a transparent resin such as acrylic resin, polyurethane resin, or silicone resin.

In the liquid crystal display of the panel 340, the liquid crystal is positioned between the glass substrates, and the polarizers are placed on both glass substrates in order to use polarization of light. Here, the liquid crystal has an intermediate property between a liquid and a solid, and liquid crystals, which are organic molecules having fluidity like a liquid, are regularly arranged like crystals. The liquid crystal has a structure in which the molecular arrangement is changed by an external electric field And displays an image.

The liquid crystal display device used in the display device uses an active matrix method as a switch for adjusting a voltage supplied to each pixel.

In addition, the front surface of the panel 340 is provided with a color filter 350. In this case, the color filter 350 transmits the light projected by the panel 340 and transmits only red, green, and blue light for each pixel, thereby representing an image.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

In addition, the above description has been made with reference to the embodiment, which is merely an example, and is not intended to limit the present invention. Those skilled in the art to which the present invention pertains will be illustrated as above without departing from the essential characteristics of the present embodiment. It will be appreciated that various modifications 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.

11: first electrode 12: second electrode
14 light emitting element 15 wire
16 bonding layer 17 lens
18: Filler 20: Package Body
100: light emitting device package 110: printed circuit board
120: bracket 200: frame
220: heat transfer member 222: heat pipe
224: Cavity 225: Metal Cover
320: light guide plate 330: optical member
340 panel 350 color filter

Claims (16)

A light emitting module having a light emitting element; And
It comprises a heat transfer member for emitting heat of the light emitting module,
The heat transfer member includes a heat absorbing part parallel to the light emitting module, a heat radiating part, and a heat transfer part connecting the heat absorbing part and the heat radiating part. The method of claim 1,
And the heat transfer member is a heat pipe having a circular cross section. The method of claim 2,
The heat pipe is a backlight unit having an oval cross section. The method of claim 1,
The heat transfer unit is a backlight unit to form an angle of 30 to 60 degrees with the heat absorbing portion. The method of claim 1,
The heat transfer member interviews the light emitting module. The method of claim 1,
The heat transfer member is a backlight unit symmetrical with respect to the center of the frame. The method of claim 1,
And a metal cover to fix the heat transfer member to the frame. The method of claim 7, wherein
The backlight unit in which the metal cover is not formed in the heat transfer part. The method of claim 7, wherein
The metal cover in the heat absorbing portion surrounds a portion of the heat transfer member. A backlight unit including a light emitting module having a light emitting element, a reflecting plate and a light guide plate provided at one side of the light source array, and a frame having a heat transfer member for dissipating heat of the light emitting module;
An optical member for projecting light projected from the backlight to a panel;
A panel provided on the optical member to implement an image by projected light; And
A color filter provided on the front surface of the panel and selectively transmitting any one of red, green, and blue light;
The heat transfer member includes a heat absorbing part parallel to the light emitting module, a heat radiating part, and a heat transfer part connecting the heat absorbing part and the heat radiating part. The method of claim 10,
And the heat transfer member is a heat pipe having an elliptical cross section. The method of claim 10,
And the heat transfer part forms an angle of 30 to 60 degrees with the heat absorber. The method of claim 10,
The heat transfer member is in contact with the light emitting module. The method of claim 10,
The heat transfer member is symmetrical with respect to the center of the frame display device. The method of claim 10,
And a metal cover to fix the heat transfer member to the frame. The method of claim 15,
The metal cover in the heat absorbing portion surrounds a portion of the heat transfer member.

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