KR200407006Y1 - Back light unit - Google Patents

Abstract

The present invention relates to a backlight unit, and more particularly to a backlight unit suitable for a large area liquid crystal display device.

According to the present invention, there is provided a backlight unit comprising: a light emitting diode (LED) light source unit in which a plurality of full color light emitting diode packages are arranged in a series of arrays; And at least one light emitting diode module having a printed circuit board (PCB) for controlling a flashing operation of each full color light emitting diode package of the light emitting diode light source unit.

Backlight unit, liquid crystal display, light emitting diode, full color light emitting diode package

Description

Backlight Unit {BACK LIGHT UNIT}

1 is a cross-sectional view showing the structure of a backlight unit according to an embodiment of the present invention;

2 is a plan view showing the configuration of an LED module according to an embodiment of the present invention,

3 is a view showing a connection configuration of the LED module shown in FIG.

* Explanation of symbols for main parts of the drawings

130: PCB 140: LED light source

140a ~ 140n: Full Color LED Package 200a ~ 200n: LED Module

201: Connector

The present invention relates to a backlight unit, and more particularly to a backlight unit suitable for a large area liquid crystal display device.

TFT-LCD, which has emerged as the core display of digital multimedia devices, cannot emit light by itself, so an external light source is required, and a device that provides this light is a back light unit (hereinafter referred to as a BLU).

On the other hand, a cold cathode fluorescent lamp (hereinafter referred to as CCFL) is used as a light source of a BLU for medium and large size liquid crystal display devices, which is easy to manufacture small and inexpensive. However, the CCFL has to apply high voltage to the anode, and due to the principle of excitation of UV wavelength to produce visible light, the color reproducibility range (hereinafter designated as NTSC), which is an important characteristic of the display device, is somewhat decreased. In addition, when manufacturing a BLU using CCFL, it is necessary to control the driving voltage of several hundred volts, so that an expensive inverter circuit is required separately, and the use of a CCFL that uses mercury in accordance with international environmental regulations is problematic.

Accordingly, the adoption of BLUs using LED as a light source has been increasing recently. The LED light source has a long lifespan and not only can manufacture a display device of NTSC 120 or more, but also can be realized only by constant current control of DC to several tens of volts.

Currently, LED is applied as a light source of a small liquid crystal display BLU used in a cell phone and a mobile, and research for applying to a large liquid crystal display BLU is being actively conducted. In particular, while developing a special high power LED package suitable for a BLU for a liquid crystal display device, the high power special LED has a problem in that the distortion of the screen of the liquid crystal display device occurs due to the high price and heat generation. For example, the power consumption per LED is about 1W, and the heat generated by 1W consumes more than 70%. The number of LEDs used in the LED BLU of the 30-inch TFT-LCD is about 200, and the heat generated from this generates 140W. The generated heat raises the temperature inside the BLU, which may lower the reliability of operation of electronic circuits, and may cause deformation of the product due to thermal stress on parts or cases due to the internal temperature difference. Currently, the flat panel display market such as TFT-LCD is moving toward larger screens. Therefore, the BLU supplying light sources also has to be large. As the BLU increases in size, the number of LEDs used increases, and the heat emitted by the LED into the backlight increases in proportion to the number of BLUs increased.

Furthermore, in order to realize white color by reducing luminance uniformity due to high power and configuring a single LED chip for each package, a section in which RGB (red, green, blue) intrinsic colors are mixed is required. There is a problem in that the display section is narrowed and the volume and thickness of the liquid crystal display device are increased.

Therefore, the present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to provide a BLU suitable for medium and large liquid crystal display device.

Another object of the present invention is to provide a BLU capable of lowering the amount of heat generated by a liquid crystal display and reducing power consumption.

Still another object of the present invention is to provide a BLU which is easy to assemble and does not generate luminance deviation in the entire liquid crystal display device.

BLU according to an embodiment of the present invention to achieve the above object

A light emitting diode (LED) light source unit in which a plurality of full color LED packages are arranged in a series of arrays; At least one LED module having a printed circuit board (PCB) for controlling the flashing operation of each of the full-color LED package configured in the light emitting diode light source unit.

Preferably, the full-color LED package is characterized in that each of the light emitting diodes of one red (R), green (G), blue (B) is integrated into one package.

Preferably, the at least one LED module can be expanded to a plurality as needed, characterized in that connected to the adjacent light emitting diode module by a connector.

Preferably, the full-color LED package is characterized in that connected to the adjacent full-color LED package by a serial-to-parallel connection method.

More preferably, the series array is characterized by a matrix structure.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. Note that the same components in the drawings are represented by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In addition, in describing the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a cross-sectional view showing the structure of a BLU 100 according to an embodiment of the present invention.

Referring to FIG. 1, the BLU 100 includes an upper frame 110 and a lower frame 120, a printed circuit board (PCB) 130, and an LED light source unit 140.

The upper frame 110 and the lower frame 120 serves as a support, it is possible to apply a variety of conventional general configuration. For example, the upper frame 110 is applied to the diffusion plate, diffusion sheet, prism sheet, protective sheet and the like is assembled, the lower frame 120 is used as the main material aluminum alloy for heat generation.

The PCB 130 is a metal or alloy such as aluminum, copper, and also uses FR4. Also, for effective heat dissipation of PCB, products such as silicon, ceramic, and nano coating materials can be attached, applied, and coated on the front and back of the PCB as a sheet or liquid form.

The LED light source unit 140 is arranged in the form of a series of array of the plurality of LEDs (140a ~ 140n) to emit light only when the current is applied to the electrode and the electrode electrically connected to the PCB 130. In particular, the LEDs 140a to 140n are full-color LED packages, and the red (R), green (G), and blue (B) LEDs are integrated into one package. In addition, the LED (140a ~ 140n) is a small full-color LED of 10mm x 10mm or less in width x length is about 0.2W power consumption, the heat generation of the LED itself is significantly reduced compared to the conventional.

Meanwhile, as the size of the BLU increases as the size of the liquid crystal display increases, the size of the PCB to which the LED is attached also increases. In order to solve this problem, the present invention proposes a modularization method of BLU using LED.

2 is a view showing the configuration of the LED module according to an embodiment of the present invention, Figure 3 is a view showing a connection configuration of the LED module shown in FIG.

Referring to FIG. 2, one LED module 200 according to the present invention includes a plurality of full-color LEDs 140a to 140n packages coupled to a series in parallel in a series array on a PCB 130, and a connector. 201). In the present embodiment, each of the n full-color LED packages has a matrix structure spaced at equal intervals from adjacent left, right, top, and bottom adjacent LED chips, but the shape of the array may be variously applied.

The series-parallel coupling method is a combination of a series and parallel structure, as shown in Figure 3 can solve the problem that occurs in the LED array (array) when expanding the size of a plurality of LEDs by combining the module unit. . For example, a result of sharing an uneven flow of current due to a difference in characteristics between LED chips due to organic coupling between devices can be obtained. Only the LED chip does not emit light, and the remaining LED chips share the current of the defective LED chip to emit light. In addition, as the number of LED chips connected in series and parallel increases, the number of LED chips compensated for the current of the LED chip in question is increased, so that the LED chip can effectively cope with the damage caused by the defective LED chips. Accordingly, when the serial connection method is applied when manufacturing a BLU, it is possible to fundamentally solve the problem that the LED chip of the entire line does not emit light due to one LED chip problem.

In addition, as shown in Figure 3, each LED module (Module1 ~ Module8, 200a ~ 200n) may be extended by connecting by using the adjacent module and the connector 201 as necessary, which is in accordance with the specifications of the power supply Therefore, there is an advantage that can be driven in various conditions. In addition, if a problem occurs with some LED packages, only that module can be replaced.

 Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below, but also by the equivalents of the claims.

As described above, the BLU according to the present invention can obtain the following effects.

First, the BLU according to the present invention uses a small full-color LED package, so the heat generation of the LED itself is very small, and by disposing the array in the form of various arrays on the front of the BLU, the heat generated from the LED can be evenly distributed over a large area. It is possible to greatly improve the screen distortion problem of the generated liquid crystal display.

Secondly, sufficient color mixing is done inside the full-color LED package to improve the color mixing problem, which is a problem of BLU manufactured using a single LED chip or a large-area LED chip, and slimming the BLU. Is possible.

Third, the present invention can improve the luminance uniformity problem that occurs when manufacturing a LED BLU using a special high-power LED by placing a small full-color LED package in a series array on the front of the BLU.

Fourth, the present invention distributes the heat generated from the LED by distributing the small full-color LED package evenly on the front of the BLU to efficiently improve the local heating problem where the LED light source is located, which is one of the biggest problems when manufacturing the conventional LED BLU. Can be.

Claims (5)

In the backlight unit, A light emitting diode (LED) light source unit in which a plurality of full color light emitting diode packages are arranged in a series of arrays; And at least one light emitting diode module having a printed circuit board (PCB) for controlling a flashing operation of each full color light emitting diode package of the light emitting diode light source unit. The method of claim 1, wherein the full color light emitting diode package And a light emitting diode of one red (R), green (G), and blue (B) integrated in one package. The method of claim 1, wherein the at least one light emitting diode module The backlight unit can be extended to a plurality as needed, and connected to the adjacent light emitting diode module by a connector. The method of claim 1 or 3, wherein the plurality of full-color light emitting diode package A backlight unit, characterized in that connected to the adjacent full-color light-emitting diode package by a serial parallel connection method. The method of claim 4, wherein the series of arrays Backlight unit characterized in that the matrix structure.

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