KR20110007319A - Light source unit and liquid crystalline display having the same - Google Patents

Abstract

PURPOSE: A light source unit and a liquid display element having the same are provided to have a reflective plate on inclined of a light guide plate, thereby maximizing the effect by performing scattering and reflection at the same time. CONSTITUTION: A bottom cover(140) has a plurality of groove of trench type. A plurality of LED(110) is arranged in serial by being separated within a groove of the bottom cover. A plurality of bar type light guide plate is arranged on a plurality of LED. The plurality of bar type light guide plate is arranged as being separated with groove of the bottom cover as a boundary.

Description

LIGHT SOURCE UNIT AND LIQUID CRYSTALLINE DISPLAY HAVING THE SAME

The present invention relates to a light source unit and a liquid crystal display device having the same, and more particularly, to a light source unit capable of high brightness and local dim and a liquid crystal display device having the same.

With the development of the information society in recent years, various forms of display devices have increased, and flat displays such as liquid crystal display (LCD), plasma display panel (PDP), electro luminescent display (ELD), and field emission display (FED) There is an active research on the device. Among them, a liquid crystal display (LCD) has been in the spotlight for high quality, mass production, ease of driving means, light weight, thinness, and low power consumption.

The liquid crystal display device displays a desired image by applying an electric field to a liquid crystal material having an anisotropic dielectric constant injected between two substrates, and adjusting the intensity of the electric field to adjust the amount of light transmitted through the substrate. Since the liquid crystal display panel of the liquid crystal display device is a non-light emitting element that does not emit light by itself, the liquid crystal display device includes a light source unit for providing light to the liquid crystal display panel.

The light source unit may be classified into a direct type and a side type according to the arrangement of the light sources. The direct type light source unit arranges a light source on a rear surface of the liquid crystal display panel to supply light directly over the entire liquid crystal display panel. The photometric light source unit arranges a light source at one edge of the rear side of the liquid crystal display panel and refracts light into the light guide plate to enter the front of the liquid crystal display panel. While the photometric light source unit can be thinned, it does not have a sufficient amount of light, so it is difficult to be applied for a large screen.

The light source unit may be classified into a fluorescent lamp and a light emitting diode (LED) according to the type of the light source. Fluorescent lamps include cold cathode fluorescent lamps ("CCFL") and external electrode fluorescent lamps ("EEFL"). LEDs are widely used because they have a long lifespan and a faster lighting speed than other fluorescent lamps, as well as low power consumption and strong impact resistance.

However, when the LED is applied to the photometric light source unit, local dim cannot be realized, and brightness cannot be adjusted in the middle of the screen, thereby degrading screen characteristics.

In order to solve the above problems, the present invention is to provide a light source unit capable of high brightness and local dim and a liquid crystal display device having the same.

The light source unit according to the present invention includes a bottom cover in which a plurality of grooves having a trench shape are formed, a plurality of LEDs arranged in a line and spaced apart in the groove of the bottom cover, and disposed on the plurality of LEDs and the grooves of the bottom cover. And a plurality of light guide plates having a bar shape spaced apart from each other, and a plurality of optical sheets disposed on the plurality of light guide plates to collect light generated by the plurality of LEDs, and one side of one light guide plate has an inclined surface. The plurality of LEDs are formed below the inclined surface.

The light source unit is disposed under the light guide plate and the LED array PCB disposed in the groove of the bottom cover, the bottom cover and supplying power to the plurality of LEDs, and the plurality of LEDs at positions corresponding to the LEDs. The LED housing further includes a number of holes formed with the same number of LEDs.

Here, the plurality of LEDs are driven with a local dim.

The inclination angle of the inclined surface is 40 ° ~ 50 °.

An inclined surface having the same shape as that of the one side surface is formed on the other side surface of the light guide plate.

The number of the light guide plate and the groove are the same, and a predetermined pattern is formed on the lower surface of the light guide plate.

The reflective plate and the LED housing are formed of the same material, and the groove is integrally formed with the bottom cover or separately formed and attached to the bottom cover.

According to an exemplary embodiment of the present invention, a liquid crystal display device includes a bottom cover having a plurality of trenches formed in a trench, a plurality of LEDs spaced in a line in the bottom cover groove, and the grooves of the bottom cover on the plurality of LEDs. A plurality of light guide plates having a bar shape spaced apart from each other and having a slope formed on one side thereof, a reflecting plate attached to the inclined surface, and disposed under the plurality of light guide plates and reflecting light generated by the plurality of LEDs to the plurality of light guide plates And a plurality of optical sheets disposed on the plurality of light guide plates to condense the light generated by the plurality of LEDs, and a liquid crystal panel disposed on the plurality of optical sheets to display a screen.

The plurality of LEDs are disposed below the inclined surface to separately drive the sections of the liquid crystal panel.

The present invention includes a plurality of bar-shaped light guide plates having an inclined surface, and includes a plurality of LEDs disposed below the inclined surface of the light guide plate to drive LEDs for each section, thereby enabling high brightness and local dim.

In addition, the light source unit according to the present invention may maximize the efficiency by simultaneously performing scattering and reflection by providing a reflecting plate on the inclined surface of the light guide plate.

In addition, the light source unit according to the present invention can directly utilize the bottom cover as a heat sink can ensure excellent heat dissipation characteristics and reliability.

Moreover, the bottom cover can improve mechanical strength by having a plurality of grooves formed in the form of trenches on the inner side to seat the LED.

Hereinafter, a light source unit and a liquid crystal display device having the same according to the present invention will be described in detail with reference to the accompanying drawings.

1 and 2, a liquid crystal display device having a light source unit according to the present invention includes a liquid crystal panel 101 for displaying an image, a driver (not shown) and a liquid crystal panel 101 for driving the liquid crystal panel 101. It includes a light source unit 102 for irradiating light.

The liquid crystal panel 101 includes a liquid crystal cell matrix and thin film transistors connected to the gate lines and the data lines to drive the liquid crystal cells, respectively. The thin film transistor of the liquid crystal panel 101 is turned on by the gate-on voltage from the gate line so that the data signal of the data line is supplied to the liquid crystal cell so that a voltage equal to the difference between the common voltage and the data signal is applied. In this case, the voltage applied to the liquid crystal cell is maintained by being turned off by the gate off voltage. The liquid crystal cell 101 displays an image by controlling the light transmittance by driving the liquid crystal according to the applied voltage.

The light source unit 102 according to the present invention includes a plurality of LEDs 110, a plurality of light guide plates 120, a plurality of reflecting plates 130, a bottom cover 140 and a plurality of optical sheets 150 for storing them. It includes. The light source unit 102 further includes an LED housing 112 and an LED array PCB (not shown).

The LED 110 generates a small number of carriers (electrons or holes) injected by using a p-n junction structure of a semiconductor, and generates light by recombination thereof. The LED 110 includes a general light emitting diode and a high brightness light emitting diode, and the general light emitting diode generates light of a constant brightness when a current is supplied, and there is no voltage drop, while a high brightness light emitting diode generates high brightness light. In addition, a voltage drop occurs.

The plurality of LEDs 110 are spaced apart from each other in the plurality of grooves 142 formed in the trench shape on the inner surface of the bottom cover 140 and are seated in a line. In this case, the plurality of LEDs 110 are disposed on the LED array PCB (not shown) disposed in the groove 142 of the bottom cover 140 and separately driven for each section of the liquid crystal panel 101. Since the plurality of LEDs 110 according to the present invention are driven separately for each section of the liquid crystal panel 101, a local dim can be implemented to adjust luminance distribution.

Here, the number of LEDs 110 is not limited to the number shown in the figure, the number of driving per section is not limited to the number shown in the figure. Although not shown in the drawings, the plurality of LEDs 110 are disposed on an LED array PCB (not shown) seated in the groove 142 of the bottom cover 140 to receive external power from the LED array PCB.

The light guide plate 120 serves to guide light incident from the LED 110 toward the display panel, and is disposed between the LED 110 and the plurality of optical sheets 150. The plurality of light guide plates 120 are spaced apart from the groove 142 of the bottom cover 140 in a bar shape. That is, the number of the grooves 142 of the light guide plate 120 and the bottom cover 140 are the same, and are formed in parallel with each other. The number of light guide plates 120 is not limited to the number shown in the drawing.

At this time, one side of the light guide plate corresponding to the portion where the LED 110 is disposed is formed to be inclined. The inclination angle is preferably 40 ° to 50 °. The other side of the light guide plate corresponding to the portion where the LED 110 is not disposed may also have a slope having the same shape as that of one side.

As such, when an inclined surface is formed on one side or both sides of the light guide plate 120 of the portion where the LED 110 is disposed, the light emitted to the outside increases, and the light emitted to the outside is collected by the liquid crystal panel 101. The brightness is improved. Meanwhile, a predetermined pattern may be formed on the rear surface of the light guide plate 120 to further improve luminance.

The reflector plate 130 is attached to one inclined surface of the light guide plate 120 to prevent loss of light generated from the LED 110. In this case, since the reflector 130 is attached to the inclined surface of the light guide plate 120 to simultaneously perform scattering and reflection, optimal light efficiency can be achieved and power consumption of the liquid crystal display device is reduced. In the drawing, the reflector 130 is shown attached to one side of the light guide plate 120, but may be attached to both inclined surfaces.

The bottom cover 140 serves to support and store the plurality of LEDs 110 and the light guide plate 120 to protect them from external impact, and is disposed at the outermost lower portion of the light source unit 102. A plurality of grooves 142 having a trench form are formed in the bottom cover 140, and the grooves 142 are integrally formed with the bottom cover 140 as shown in the drawing, or not shown in the drawing. It is formed in the shape of a bar upright can be attached to the bottom cover 140.

When the grooves 142 are separately formed and attached to the bottom cover 140, a plurality of holes (not shown) in the form of a plurality of grooves are formed in the bottom cover 140, and the grooves are fitted into the holes. On the other hand, it is preferable to form the groove 142 integrally with the bottom cover 140 in terms of the manufacturing process.

The bottom cover 140 forms a plurality of trenches 142 in the form of trenches to mount the plurality of LEDs 110 in the grooves 142, thereby improving mechanical strength and making the liquid crystal display device thin. In addition, the bottom cover 140 may be directly used as a heat sink to dissipate heat generated from the plurality of LEDs 110 to ensure reliability of the liquid crystal display device.

The plurality of optical sheets 150 collect light incident from the light guide plate 120 and the reflecting plate 130 in a direction perpendicular to the display surface of the display panel, and the diffusion sheet 152 and the prism sheet 154. ) And a protective sheet 156 and the like.

The diffusion sheet 152 is disposed on the light guide plate 120 to scatter light emitted from the light guide plate 120 so that uniform light is emitted. The prism sheet 154 is disposed on the diffusion sheet 152 and serves to condense the light diffused by the diffusion sheet 152. The protective sheet 156 is disposed on the prism sheet 154, and serves to protect the prism sheet 154 from the top and scatter the light that enters to emit uniform light.

The LED housing 112 serves as a guide to direct the light generated from the LED 110 to the light guide plate 120, and is formed between the bottom cover 140 and the light guide plate 120. Specifically, the LED housing 112 is disposed in the groove 142 of the bottom cover 140 to fit inside the groove 142 of the bottom cover 140 as shown in FIGS. 3A and 3B. The LED housing 112 is disposed in the groove 142 at the bottom of the light guide plate 120 except where the LED 110 is located to reflect light directed below the light guide plate 120 onto the light guide plate 120.

In this case, a plurality of holes 114 corresponding to the number of LEDs 110 formed in one groove 142 are formed in the LED housing 112 fitted inside the one groove 142. The hole 114 is formed in the same shape as the circumference of the LED 110, and the light generated in the LED 110 is emitted to the light guide plate 120 through the hole 114. The LED housing 112 may be formed of the same material as the reflector 130, but is not limited thereto.

Accordingly, the light generated by the LED 110 is directed to the light guide plate 120 directly by the LED housing 112 as shown in FIG. 4, and the light directed to the light guide plate 120 is applied to the light guide plate 120 and the light guide plate 120. Scattered and reflected by the reflecting plate 130 formed on the inclined surface to the light diffusing sheets, the light is collected through the diffusion sheet 152, prism sheet 154 and the protective sheet 156 to exit to the liquid crystal panel 101 do. In addition, the plurality of LEDs 110 are driven for each section of the liquid crystal panel 101.

As described above, the present invention includes a plurality of bar-shaped light guide plates having inclined surfaces, and includes a plurality of LEDs disposed below the inclined surfaces of the light guide plates to drive LEDs for each section of the liquid crystal panel, thereby enabling high brightness and local dim. In addition, the reflector plate formed on the inclined surface of the light guide plate and the LED housing disposed below the light guide plate can maximize efficiency by simultaneously scattering and reflecting light generated from the LED.

In addition, the bottom cover can be used directly as a heat sink to ensure excellent heat dissipation characteristics and to ensure reliability, and the bottom cover can improve mechanical strength by having a plurality of grooves formed in the trench on the inner surface.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

1 is a cross-sectional view of the liquid crystal display device according to the present invention cut into one side;

2 is a cross-sectional view of the liquid crystal display device according to the present invention cut into the other side.

3A and 3B are perspective views for explaining in detail the LED housing of the light source unit according to the present invention.

4 is a view for explaining an optical path by the light source unit according to the present invention.

<< Explanation of symbols for main part of drawing >>

101: liquid crystal panel 102: light source unit

110: LED 112: LED housing

114: hole 116: LED array PCB

120: light guide plate 130: reflector

140: bottom cover 142: groove

150: multiple optical sheets

Claims (10)

A bottom cover having a plurality of trenches formed in a trench; A plurality of LEDs arranged in a line and spaced apart in the groove of the bottom cover; A plurality of light guide plates of a bar shape disposed on the plurality of LEDs and spaced apart from the groove of the bottom cover; A plurality of optical sheets disposed on the plurality of light guide plates to condense the light generated by the plurality of LEDs; An inclined surface is formed on one side of one light guide plate, and the plurality of LEDs are disposed under the inclined surface. The method of claim 1, wherein the reflecting plate attached to the inclined surface, An LED array PCB disposed in the groove of the bottom cover to supply power to the plurality of LEDs; And a LED housing disposed below the light guide plate and having a number of holes equal to the number of the plurality of LEDs at positions corresponding to the LEDs. The light source unit of claim 1, wherein the plurality of LEDs are driven with a local dim. The light source unit of claim 1, wherein the inclination angle of the inclined surface is 40 ° to 50 °. The light source unit of claim 1, wherein an inclined surface having the same shape as that of the one side surface is formed on the other side surface of the light guide plate. The method of claim 1, wherein the number of the light guide plate and the groove is the same, The light source unit, characterized in that a predetermined pattern is formed on the lower surface of the light guide plate. The method of claim 2, wherein the reflecting plate and the LED housing is formed of the same material, The groove is a light source unit, characterized in that formed integrally with the bottom cover or formed separately and attached to the bottom cover. A bottom cover having a plurality of trenches formed in a trench; A plurality of LEDs arranged in a line and spaced apart in the groove of the bottom cover; A plurality of light guide plates having a bar shape disposed on the plurality of LEDs spaced apart from the groove of the bottom cover and having an inclined surface on one side thereof; A reflection plate attached to the inclined surface; An LED housing disposed under the plurality of light guide plates and reflecting light generated by the plurality of LEDs to the plurality of light guide plates; A plurality of optical sheets disposed on the plurality of light guide plates to condense the light generated by the plurality of LEDs; And And a liquid crystal panel disposed on the plurality of optical sheets to display a screen. The liquid crystal display device of claim 8, wherein the plurality of LEDs are disposed under the inclined surface and separately driven by sections of the liquid crystal panel. The method of claim 8, wherein the plurality of LEDs are disposed below the inclined surface, The inclination angle of the inclined surface is 40 ° ~ 50 °, And an inclined surface having the same shape as that of the one side surface on the other side surface of the light guide plate.

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