KR20070002755A - Backlight unit - Google Patents

Abstract

A backlight unit is provided to reduce the number of light emission lamps controlled by each transformer and stably supply an electric current to each light emission lamp by dividing common electrodes at both ends of the light emission lamps and constructing a transformer corresponding to each divided common electrode. A plurality of light emission lamps(41) are arranged on a cover bottom(40) at predetermined intervals therebetween, and have first and second electrodes(44a) at both ends outside a pipe. A plurality of common electrodes(42a,42b,43a,43b) are n-divided for two or more at both ends of the light emission lamps. A plurality of screws fix the common electrodes to a lower portion of the cover bottom. First and second inverter PCBs(Printed Circuit Boards) are disposed at both sides of a back surface of the cover bottom. A plurality of transformers are disposed such that n transformers are provided for the first and second inverter PCBs corresponding to the common electrodes. A plurality of wires are connected between the screws and the transformers.

Description

Backlight unit {BACKLIGHT UNIT}

1 is a schematic plan view of a direct-type backlight unit according to the prior art;

Fig. 2 is a schematic view showing the back surface of the backlight unit of Fig.

3 is a perspective view of a backlight unit according to an embodiment of the present invention.

4 is a rear view of a backlight unit according to an embodiment of the present invention.

FIG. 5 is an enlarged perspective view of the 'A'

FIG. 6 is an enlarged perspective view of the 'B' region of FIG.

Description of the Related Art [0002]

40: Cover Bottom 41: Luminescent lamp

42a, 42b: first and second common electrodes 43a, 43b: third and fourth common electrodes

44a, 44b: first and second electrodes

45a, 45b, 45c, 45d: first to fourth screws

46a, 46b: first and second wires 47a, 47b: third and fourth wires

51a, 51b: first and second inverter PCBs 52a, 52b: first and second transformers

53a, 53b: third and fourth transformers

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and more particularly, to a backlight unit in which a common electrode is divided and a transformer is constructed so as to stabilize driving.

CRT (Cathode Ray Tube), which is one of the commonly used display devices, is mainly used for monitors such as TVs, measuring instruments, information terminals, etc. However, due to its own weight and size, We could not actively cope with the demand.

Therefore, in the trend of miniaturization and light weight of various electronic products, CRT has a certain limit in weight and size, and is expected to replace the liquid crystal display (LCD) using an optical field effect, A plasma display panel (PDP) and an electroluminescence display (ELD) using an electroluminescence effect. Among them, researches on liquid crystal display devices are being actively carried out.

Liquid crystal display devices having advantages such as small size, light weight and low power consumption have been actively developed to replace such a CRT, and recently, they have been sufficiently developed to perform a role as a flat panel display device, A monitor of a desktop type computer, a large information display device, and the like, and the demand of the liquid crystal display device is continuously increasing.

Since most of such liquid crystal display devices are light receiving devices that display images by adjusting the amount of light coming from the outside, a separate light source for illuminating the LCD panel, that is, a back light unit is necessarily required.

Generally, a backlight unit used as a light source of a liquid crystal display device is a method of arranging a cylindrical fluorescent lamp, and it is divided into an edge type and a direct type.

First, in the edge method, a lamp unit is installed on a side surface of a light guide plate for guiding light. The lamp unit includes a lamp that emits light, a lamp holder inserted in both ends of the lamp to protect the lamp, And a lamp reflector that is fitted to the side surface of the light guide plate and reflects the light emitted from the lamp toward the light guide plate.

The edge method in which the lamp unit is installed on the side surface of the light guide plate is applied to a liquid crystal display device having a comparatively small size such as a monitor of a laptop type computer and a desktop type computer and has a good uniformity of light, Which is advantageous for reducing the thickness of the liquid crystal display device.

Meanwhile, the direct-type liquid crystal display device has begun to be developed as the size of the liquid crystal display device becomes larger than 20 inches, and a plurality of lamps are arranged in a row on the lower surface of the diffusion plate, will be.

This direct-down scheme is mainly used for a large-screen liquid crystal display device which requires a high luminance because the utilization efficiency of light is higher than that of the edge scheme.

However, in the case of the liquid crystal display device adopting the direct-down method, since it is used for a large-sized monitor or a television, the time for use is longer than that of a laptop-type computer and the number of lamps is large, There is a greater possibility that a lamp that is not illuminated due to the lamp failure or the life of the display device is displayed.

As the light sources of the edge type and direct-down type liquid crystal display devices, there are EL (Electro Luminescence), LED (Light Emitting Diode), Cold Cathode Fluorescent Lamp (CCFL), Hot Cathode Fluorescent Lamp (HCFL), External Electrode Fluorescent Lamp ) Can be used.

Hereinafter, a backlight unit according to the prior art will be described as follows.

1 is a plan view of a direct-type backlight unit using EEFL, and Fig. 2 is a schematic view showing a back surface of the backlight unit according to Fig.

As shown in Figs. 1 and 2, the conventional direct-type backlight unit has first and second electrodes 12a and 12b at both ends outside the tube on the cover bottom 10 and arranged at regular intervals A plurality of light emitting lamps 11 and first and second common electrodes 12a and 12b arranged in one direction at both ends to apply a driving current to the first and second electrodes 12a and 12b at both ends of the light emitting lamp 11, First and second inverter PCBs 14a and 14b disposed on the backside of the cover bottom 10 to apply a driving current to the first and second common electrodes 13a and 13b, First and second transformers 15a and 15b provided on the first and second inverter PCBs 14a and 14b and first and second common electrodes 13a and 13b and first and second common electrodes 13a and 13b, And first and second wires 17a and 17b connecting the transformers 15a and 15b. The first and second wires 17a and 17b are connected to the first and second transformers 15a and 15b by the first and second connectors 16a and 16b.

As described above, the conventional backlight unit has the following problems.

As described above, when a current is supplied to a plurality of light emitting lamps by a transformer provided on both sides of the light emitting lamps 11 irrespective of the number of the light emitting lamps 11, There arises a problem that an equal current is not applied to each lamp.

If uniform current is not applied to each of the light emitting lamps as described above, luminance uniformity of the backlight unit decreases and a problem of quality defects arises.

It is an object of the present invention to provide a backlight unit suitable for stabilizing driving by dividing common electrodes at both ends of a light emitting lamp and correspondingly constituting a transformer.

According to an aspect of the present invention, there is provided a backlight unit comprising: a plurality of light emitting lamps having first and second electrodes at both ends of a tube on a cover bottom and arranged at regular intervals; A plurality of common electrodes formed on both ends of the light emission lamp, A plurality of screws for fixing the common electrodes to the bottom of the cover bottom; First and second inverter PCBs disposed on both sides of the cover bottom back surface; A plurality of transformers each of which is provided in each of the first and second inverter PCBs corresponding to the common electrodes; And a plurality of wires connected between the screws and the transformers.

And the common electrodes are formed in a gripper type so as to cover and fix both ends of the luminescent lamp.

The common electrodes include a plurality of fastening portions having two or more slits for restricting the first and second electrodes at both ends of the light emitting lamp and spaced apart from each other, and a plurality of fastening portions formed on both sides of the fastening portions for connecting the fastening portions. The first common electrode line and the second common electrode line are formed vertically at the ends of the first or second common electrode line on which the ends of the respective light emission lamps are mounted in order to prevent the light emission lamp from being horizontally biased during lamp assembly A stopper, and a plurality of holes formed in a portion where the screw is to be fastened.

Hereinafter, a backlight unit according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 3 is a partial perspective view of a backlight unit according to an embodiment of the present invention, and FIG. 4 is a rear view of a backlight unit according to an embodiment of the present invention.

FIG. 5 is an enlarged perspective view of the 'A' region of FIG. 3, and FIG. 6 is an enlarged perspective view of the 'B' region of FIG.

3, 4, 5 and 6, the backlight unit according to the embodiment of the present invention has first and second electrodes 44a and 44b at both ends outside the tube on the cover bottom 40, A driving current is applied to the first and second electrodes 44a and 44b at both ends of the luminescent lamp 41 and the luminescent lamp 41 is fixed to the gripper 41. [ The first and second common electrodes 42a and 42b and the third and fourth common electrodes 43a and 43b are formed in a gripper type, First to fourth screws 45a, 45b, 45c, 45d for fixing the third and fourth common electrodes 42a, 42b, 43a, 43b to the lower portion of the cover bottom 40, The first and second inverter PCBs 51a and 51b disposed on both sides of the backside of the cover bottom 40 for applying driving current to the first, second, third, and fourth common electrodes 42a, 42b, 43a, , 51b), the first and second common electrodes 4 Second and third transformers 52a and 52b provided on the first inverter PCB 51a in correspondence with the first and second common electrodes 43a and 43b, Third and fourth transformers 53a and 53b and first through fourth screws 45a and 45b and 45c and 45d and first through fourth transformers 52a and 52b provided on the inverter PCB 51b, Second, third, and fourth wires 46a, 46b, 47a, and 47b connected to the first, second, third, and fourth wires 53a and 53b.

The first, second, third, and fourth common electrodes 42a, 42b, 43a, and 43b may be formed as slits (not shown) for restricting the first and second electrodes 44a and 44b at both ends of the light- The first and second common electrode lines are formed on both sides of the fastening part to connect the fastening parts. The first and second common electrode lines are formed on the left and right sides of the light emitting lamp 41, A stopper formed vertically in the longitudinal direction at the end of the first or second common electrode line on which the end of each light emitting lamp 41 is seated, ).

The fastening portion is formed in a gripper type so as to surround the light emitting lamp 41 and has at least two slits in the middle so that the light emitting lamp 41, It is possible to reduce the contact failure with the light emitting lamp 41 and to maximize the contact area with the light emitting lamp 41, thereby improving the electrical continuity / conductivity.

The common electrodes for supplying the driving current to the first and second electrodes 44a and 44b of the light emitting lamp 41 and fixing the light emitting lamp 41 are respectively provided in two on both sides of the light emitting lamp 41 Or may be divided into two or more, for example, n.

In the case where the common electrode is divided into n pieces on both sides, the transformers in the first and second inverter PCBs are also formed in a number corresponding to one-to-one correspondence, and n Respectively.

As described above, the common electrode for supplying the driving current to the first and second electrodes of the plurality of light emitting lamps 41 is divided and the transformer is formed correspondingly, thereby reducing the number of the light emitting lamps to be controlled per transformer And accordingly, the current can be applied to the luminescent lamp more stably.

Although not shown in the drawing, a diffusion sheet for scattering the light emitted from the light emitting lamp 41 is disposed above the light emitting lamp 41 so that a uniform light source distribution can be formed on the display surface of the liquid crystal panel. And a light scattering means such as a diffusion plate are further disposed.

A reflection plate (not shown) is further disposed on the inner surface of the cover bottom 40 so as to irradiate the light generated from the light emission lamp 41 to the display unit of the liquid crystal panel. This is to maximize utilization efficiency of light .

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 of the invention.

Accordingly, the technical scope of the present invention should not be limited to the contents described in the above embodiments, but should be determined by the claims.

The backlight unit according to the present invention has the following effects.

The common electrodes on both ends of the luminescent lamp are divided and constituted so as to constitute a transformer corresponding to each of the divided common electrodes so that the number of luminescent lamps to be controlled per transformer is reduced to stably supply current to each luminescent lamp It is easy.

Accordingly, the luminance uniformity of the backlight unit is improved, and the quality of the entire liquid crystal display device can be improved.

Claims (3)

A plurality of light emitting lamps having first and second electrodes on both ends of the tube on the cover bottom and arranged at regular intervals; A plurality of common electrodes formed on both ends of the light emission lamp, A plurality of screws for fixing the common electrodes to the bottom of the cover bottom; First and second inverter PCBs disposed on both sides of the cover bottom back surface; A plurality of transformers each of which is provided in each of the first and second inverter PCBs corresponding to the common electrodes; And a plurality of wires connected between the screws and the transformers. The method according to claim 1, Wherein the common electrodes are formed in a gripper type so as to surround and clamp both ends of the light emitting lamp. The method according to claim 1, The common electrodes include a plurality of fastening portions spaced apart from each other with at least two slits for restricting the first and second electrodes at both ends of the light emitting lamp, First and second common electrode lines formed on both sides of the coupling portion to connect the coupling portions, A stopper formed vertically in a longitudinal direction at an end of the first or second common electrode line on which the end of each of the light emitting lamps is seated to prevent the light emitting lamp from being horizontally biased when assembling the lamp, And a plurality of holes formed in a portion where the screw is to be fastened.

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