KR20060095829A - Back light unit and liquid crystal display device having the same - Google Patents

Abstract

The present invention provides a backlight unit suitable for improving mechanical strength and assemblability of a large LED backlight unit and preventing flipping of a reflector and a liquid crystal display device having the same. Bottom and; A plurality of PCB substrates disposed on the cover bottom and spaced apart from each other by a predetermined interval; A plurality of LED lamps disposed in one direction on the PCB substrate; A reflector configured to transmit light generated by the LED lamp upwards; And an extrusion bar configured to support the reflecting plate between the PCB substrates.

Extrusion bar, rivet, reflector, cover bottom

Description

BACK LIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE SAME}

1 is a perspective view showing an example of a conventional direct type backlight unit

2 is a perspective view of a backlight unit according to an embodiment of the present invention;

3 is a layout view showing the arrangement of the LED lamp and the extrusion bar according to the present invention

4 is a cross-sectional view taken along line II ′ of FIG. 3.

5a to 5g are views showing various forms of extrusion bar that can be applied to the present invention

6 is a perspective view of a liquid crystal display device having a backlight unit according to the present invention;

Explanation of symbols on the main parts of the drawings

21: cover bottom 22: PCB substrate

23: LED lamp 24: reflector

25 extruded bar 26 light scattering means

27: rivet 30: liquid crystal panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and more particularly, to a backlight unit suitable for improving mechanical strength and a flipping phenomenon of a reflecting plate when an LED is used for a large display device, and a liquid crystal display having the same.

CRT (Cathode Ray Tube), one of the commonly 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, We couldn't respond actively to demands.

Therefore, in the trend of miniaturization and light weight of various electronic products, CRT has a certain limit in weight and size.

It is expected that the CRT will be replaced by a liquid crystal display (LCD) using an electro-optical effect, a plasma display device (PDP) using a gas discharge, and an EL display device using an electroluminescent effect ( ELD (Electro Luminescence Display) and the like, among them, researches on liquid crystal display devices are actively conducted.

In order to replace the CRT, liquid crystal display devices having advantages such as small size, light weight, and low power consumption have been actively developed. Recently, the liquid crystal display device has been developed enough to perform a role as a flat panel display device. As it is used for a monitor of a desktop computer and a large information display device, the demand for a liquid crystal display device is continuously increasing.

Since most of the liquid crystal display devices are light-receiving devices that display an image by controlling the amount of light coming from the outside, a separate light source for irradiating light to the liquid crystal panel, that is, a back light unit is necessary. .

In general, a backlight unit used as a light source of a liquid crystal display device is a method of disposing a cylindrical light emitting lamp, and is divided into an edge method and a direct method.

In the double-edge method, the lamp unit is installed on the side of the light guide plate for guiding the light, and the lamp unit covers a lamp emitting light, a lamp holder inserted at both ends of the lamp to protect the lamp, and an outer circumferential surface of the lamp, and one side It is provided with a lamp reflector plate fitted to the side of the light guide plate to reflect the light emitted from the lamp toward the light guide plate.

The edge method in which the lamp unit is installed on the side of the light guide plate is applied to a relatively small liquid crystal display device such as a monitor of a laptop computer and a desktop computer, and has good uniformity of light and a long service life. It is advantageous to thin the liquid crystal display device.

On the other hand, the direct method began to develop mainly as the size of the liquid crystal display device became larger than 20 inches, and arranged a plurality of lamps in a row on the lower surface of the diffusion plate to direct light directly to the front of the liquid crystal panel. will be.

The direct method is mainly used for a large screen liquid crystal display device requiring high luminance because the light utilization efficiency is higher than that of the edge method.

Hereinafter, a conventional backlight unit will be described with reference to the accompanying drawings.

1 is a perspective view showing a conventional direct type backlight unit.

As shown in FIG. 1, a conventional backlight unit includes a plurality of light emitting lamps 1, an outer case 3 for fixing and supporting the light emitting lamps 1, the light emitting lamps 1, and a liquid crystal panel. It is composed of a diffusion plate 5a disposed between (not shown) and a plurality of diffusion sheets 5b and 5c disposed on the diffusion plate 5a.

The outer case 3 supports the light emitting lamp 1, and a reflecting plate 7 is disposed on an inner surface of the outer case 3 so that light generated from the light emitting lamp 1 can be concentrated and irradiated to the display unit of the liquid crystal panel. This is to maximize the utilization efficiency of light. At this time, the reflecting plate 7 is formed with a bend to have a concave shape in the lower portion of the light emitting lamp (1).

The light emitting lamp 1 is a Cold Cathode Fluorescent Lamp (CCFL), and electrodes are disposed at both ends of a tube, and power leads 9a and 9b are respectively connected to the electrode. .

Both ends of the light emitting lamp 1 are fitted in grooves formed on both sides of the outer case 3.

When a voltage is applied to the electrode part through the power lead wires 9a and 9b, the light emitting lamp 1 emits light to serve as a light source of the liquid crystal display.

Compared to the edge type backlight unit, the direct type backlight unit can use a plurality of light sources to ensure high brightness, but when applied to an LCD TV, it is used to control the image quality and the brightness of each region. There is a limit.

The present invention has been made to solve the above problems, in particular, to improve the mechanical strength and assembly of the large LED backlight unit, and to prevent the flipping of the reflector plate and a liquid crystal display device having the same The purpose is to provide.

The backlight unit according to the present invention for achieving the above object is a cover bottom; A plurality of PCB substrates spaced apart from each other by a predetermined interval on the cover bottom; A plurality of LED lamps disposed in one direction on the PCB substrate; A reflector configured to transmit light generated by the LED lamp upwards; And an extrusion bar configured to support the reflecting plate between the PCB substrates.

The LED lamp is characterized in that divided into a light emitting portion and a body portion.

The reflective plate is provided with a plurality of holes (holes) in a portion corresponding to the LED lamp, characterized in that the hole is formed so as to fit in the boundary region of the light emitting portion and the body portion of the LED lamp.

The extrusion bar is characterized in that composed of aluminum.

The extrusion bar is characterized in that configured on the cover bottom to a height capable of supporting the reflecting plate.

A plurality of holes are formed in one region of the extruded bar and the cover bottom corresponding thereto, and the extruded bar and the cover bottom are fastened by using a rivet to the plurality of holes.

The extrusion bar and the cover bottom is characterized in that it further comprises fastening with a screw (screw).

The extrusion bar is characterized in that the tubular rectangular structure is arranged in one direction or spaced apart at regular intervals.

The extrusion bar is characterized in that consisting of a rectangular shape with a passage therein.

The extrusion bar is characterized in that the center portion is configured to a thickness capable of supporting the reflector, and the edge is configured to have a thickness thinner than the center portion.

And the center portion of the extrusion bar is in contact with the reflector or the center portion of the extrusion bar is in contact with the cover bottom.

The extrusion bar is characterized in that both edge portions are configured to have a thickness capable of supporting the reflecting plate, and the middle portion is configured to have a thickness thinner than the edges.

It characterized in that it further comprises a passage provided in the interior of the extrusion bar.

A liquid crystal display device having a backlight unit according to the present invention having the above-described configuration includes a liquid crystal panel including first and second glass substrates bonded to each other with a predetermined space on an upper portion of the backlight unit and a liquid crystal layer filled therebetween. Characterized in that it comprises a.

Hereinafter, a backlight unit and a liquid crystal display having the same according to the present invention will be described with reference to the accompanying drawings.

2 is a perspective view of a backlight unit according to an embodiment of the present invention, Figure 3 is a layout view showing the arrangement of the LED lamp and the extrusion bar according to the present invention.

4 is a cross-sectional view taken along line II ′ of FIG. 3, and FIGS. 5A to 5G are views illustrating various forms of extrusion bars applicable to the present invention.

6 is a perspective view of a liquid crystal display device having a backlight unit according to the present invention.

First, as illustrated in FIGS. 2, 3, and 4, a backlight unit according to an exemplary embodiment of the present invention includes a plurality of PCB substrates disposed on the cover bottom 21 and spaced apart from each other by a predetermined interval on the cover bottom 21. (22), a plurality of LED lamps (23) arranged in one direction on the PCB substrate 22, a reflector (24) configured to transfer upward the light generated by the LED lamp 23, and It consists of an extrusion bar 25 formed in a spaced area of the PCB substrate 22 and configured to support the reflecting plate 24, and light scattering means 26 disposed on the reflecting plate 24.

The cover bottom 21 is formed over the entire lower surface including the PCB substrate 22, and the LED lamp 23 is divided into a light emitting part and a body part.

The LED lamp 23 is a solid-state device using a photoelectric conversion effect of a semiconductor, and since a DC voltage of about 1.5V is applied to emit light of an LED, a DA-AC converter is not required and power consumption can be greatly reduced.

Moreover, since the LED lamp 23 is a semiconductor device, it is more reliable than a cathode ray tube, and is small and long life.

The reflection plate 24 is provided with a plurality of holes corresponding to the light emitting portion of the LED lamp 23 so as to fit in the boundary region of the light emitting portion and the body portion of the LED lamp 23.

In addition, the PCB substrate 22 arranged in one direction in which the LED lamps 23 are disposed is made of a metal and has a driving circuit for driving the LED lamps.

When the backlight unit having the above structure is applied to a large display device, the reflector 24 is also enlarged, whereby a ringing or distortion of the reflector 24 may occur.

In order to prevent the ringing or warping of the reflector 24 as described above, in the present invention, an extrusion bar 25 made of aluminum is further provided in a spaced area of the PCB substrate 22.

At this time, the extrusion bar 25 is configured on the cover bottom 21 at a height capable of supporting the reflecting plate 24. In order to fix the extrusion bar 25, a plurality of holes are formed in one region of the extrusion bar 25 and the cover bottom 21 corresponding thereto.

The extrusion bar 25 and the cover bottom 21 are fastened to each of the plurality of holes using a rivet 27.

The parts joined using the rivets 27 as described above are called rivet joints, and there are overlapping joints, butt joints, parallel rivet joints and zigzag rivet joints, shear surface joints, and the like. Such rivet joints are easy to work with and can also strengthen the strength of the joint.

By using the rivet 27 as described above it is possible to strengthen the fastening force of the extrusion bar 27 and the cover bottom 21, it is possible to improve the mechanical strength of the cover bottom (21).

The extrusion bar 25 and the cover bottom 21 may be fastened with a screw.

By constituting the extrusion bar 25 with aluminum in the above, it is possible to facilitate heat dissipation generated when the backlight unit is used.

The extrusion bar 25 may be arranged in one direction between the PCB substrate 22, and although not shown in the drawing, the extrusion bar 25 may be formed in an island shape in a region where the extrusion bar 25 is coupled to the cover bottom 21 at regular intervals.

The above-described extruded bar 25 may have a thickness capable of supporting the reflector 24, and may be configured in a rectangular shape as a cylinder as in FIG. 5A, or may be configured as a rectangle as in FIG. 5B. A passage may be provided inside in order to make it lighter than the extrusion bar 25 used as the cylinder.

As shown in FIGS. 5C and 5D, the extrusion bar 25 may be configured to have a thickness in which the center portion may support the reflector 24, and the edge may have a thickness thinner than the center. 5C, the center portion of the extrusion bar 25 is in contact with the reflector 24, and FIG. 5D is the center portion of the extrusion bar 25 is in contact with the cover bottom 21.

And as shown in Figure 5e, the extrusion bar 25 may be configured such that both edge portions to a thickness capable of supporting the reflecting plate 24, the center portion to have a thickness thinner than the edge. At this time, the edge portion of the extrusion bar 25 is in contact with the cover bottom 21.

5F and 5G, the shape of the extrusion bar 25 is formed as shown in Figs. 5F and 5G, and is formed by forming a passage therein to make it lighter than the extrusion bar 25. It may be.

In addition to the shape described above, the extrusion bar 25 may be configured to have various shapes capable of supporting the reflecting plate 24.

Next, in the liquid crystal display device using the backlight unit according to the embodiment of the present invention having the above configuration, the liquid crystal panel 30 is further configured on the light scattering means 26 of the backlight unit. It is.

Although not shown in the drawing, the liquid crystal panel 30 includes upper and lower glass substrates and a liquid crystal layer filled therebetween.

In this case, the lower glass substrate includes a plurality of gate lines arranged in one direction at a predetermined interval, a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines, and the gate lines and the data lines intersect each other. A plurality of pixel electrodes formed in a matrix form in each defined pixel region, and a plurality of thin film transistors (TFTs) which are switched by signals of the gate lines to transfer the signals of the data lines to the pixel electrodes are formed. .

On the upper glass substrate, a black matrix layer is formed to block light except for the pixel region, and R (Red), G (Green), and B (Blue) cells transmit only light of a specific wavelength band and absorb the remaining light. The color filter layer and the common electrode for implementing an image are comprised.

The liquid crystal panel 30 may be configured by a transverse electric field method in which a common electrode is formed on a lower glass substrate.

The backlight unit configured as described above mixes the light emitted from the red, green, and blue LEDs emitting three primary colors of additive mixed color to obtain white light and illuminates the liquid crystal panel.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in Esau.

The backlight unit and the liquid crystal display having the same according to the present invention as described above have the following effects.

First, by providing an aluminum extrusion bar between the PCB substrate to support the reflector, it is possible to solve the problem of luminance unevenness due to the distortion and ringing of the reflector.

Second, by integrating the aluminum extrusion bar and the cover bottom by riveting, it is possible to increase the assemblability of the large LED backlight unit and reinforce the mechanical strength of the cover bottom.

Third, heat dissipation generated when using the backlight unit can be facilitated by configuring the extrusion bar with aluminum.

Fourth, by using the LED lamp, it is possible to control the image quality improvement and luminance by zone.

Claims (14)

A cover bottom; A plurality of PCB substrates disposed on the cover bottom and spaced apart from each other by a predetermined interval; A plurality of LED lamps disposed in one direction on the PCB substrate; A reflector configured to transmit light generated by the LED lamp upwards; And an extrusion bar configured to support the reflecting plate between the PCB substrates. The method of claim 1, The LED lamp is divided into a light emitting unit and a body unit, characterized in that the backlight unit. The method of claim 2, The reflector is provided with a plurality of holes (hole) in a portion corresponding to the LED lamp, the backlight unit, characterized in that the hole is fitted to the boundary region of the light emitting portion and the body portion of the LED lamp. The method of claim 1, And said extrusion bar is made of aluminum. The method of claim 1, The extrusion bar is a backlight unit, characterized in that configured on the cover bottom to a height capable of supporting the reflecting plate. The method of claim 1, A plurality of holes are formed in one region of the extrusion bar and the cover bottom corresponding thereto, and the extrusion bar and the cover bottom are fastened by using a rivet to the plurality of holes. . The method of claim 1, And the extrusion bar and the cover bottom are fastened by screws. The method of claim 1, The extrusion bar is a backlight unit, characterized in that the rectangular structure of the tubular structure is arranged in one direction or spaced apart at regular intervals. The method of claim 1, The extrusion bar is a backlight unit, characterized in that consisting of a rectangular shape with a passage therein. The method of claim 1, The extrusion bar is a backlight unit, characterized in that the center portion is configured to a thickness capable of supporting the reflecting plate, the edge portion to have a thickness thinner than the center portion. The method of claim 10, And the center portion of the extrusion bar is in contact with the reflector or the center portion of the extrusion bar is in contact with the cover bottom. The method of claim 1, The extrusion bar is a backlight unit, characterized in that both edge portions are configured to have a thickness capable of supporting the reflecting plate, and the center portion has a thickness thinner than the edge. The method of claim 10, And a passage is provided inside the extrusion bar. A backlight unit comprising claim 1; And a liquid crystal panel comprising first and second glass substrates bonded to each other with a predetermined space on the backlight unit and a liquid crystal layer filled therebetween.

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