KR20050065814A - Apparatus driving back light unit - Google Patents

Abstract

The present invention relates to a drive unit of a backlight unit capable of making the temperature deviation of a lamp uniform.

A driving apparatus of a backlight unit according to an exemplary embodiment of the present invention includes a lamp having a high voltage electrode to which an AC signal is applied and a low pressure electrode to which a common voltage is applied, and a position of the lamp unit that is close to the low pressure electrode side of the lamp. And a signal transmission cable for transferring an AC signal from the inverter to the high voltage electrode of the lamp.

Such, the present invention can prevent the movement phenomenon of mercury due to the temperature deviation by making the temperature deviation of the lamp uniform. Therefore, the present invention can improve the life of the lamp by preventing the pink discharge of the lamp by preventing the movement of mercury injected into the plurality of lamps.

Description

Driving device for backlight unit {APPARATUS DRIVING BACK LIGHT UNIT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a driving unit of a backlight unit capable of making the temperature deviation of a lamp uniform.

In general, liquid crystal displays (hereinafter referred to as "LCDs") have tended to be gradually widened due to their light weight, thinness, and low power consumption. According to this trend, LCDs are used for office automation equipment, audio / video equipment, and the like. On the other hand, the LCD is controlled to display the desired image on the screen by adjusting the transmission amount of the light beam according to the image signal applied to the plurality of control switches arranged in a matrix form.

Since the LCD is not a self-luminous display device, a light source such as a back light unit is required. There are two kinds of LCD backlight units, a direct type type and an edge type type. The direct type places several lamps in a plane. A diffusion plate is installed between the lamp and the liquid crystal panel to maintain a constant space between the liquid crystal panel and the lamp. This direct type is mainly used for large LCDs such as televisions. In the edge type system, a lamp is installed outside the flat plate to irradiate the liquid crystal panel with light from the lamp using a transparent light guide plate. This edge type method is mainly used for notebook computers or monitors.

1 and 2, a driving apparatus of a conventional backlight unit includes a plurality of lamps 12 including a high voltage electrode HIGH and a low voltage electrode LOW and arranged side by side at predetermined intervals, A backlight unit including a lamp housing 20 for accommodating lamps 12, a non-illustrated diffuser plate covering a front surface of the lamp housing, and a plurality of non-illustrated optical sheets stacked on the diffuser plate; An inverter unit 32 disposed on one rear surface of the lamp housing 20 so as to be adjacent to the high voltage electrode portion of each of the plurality of lamps 12 and generating an AC waveform having a high voltage for driving the plurality of lamps 12; ; A first printed circuit board 30 disposed on one rear surface of the lamp housing 20 and mounted with an inverter unit 32; A second printed circuit board 40 disposed on the other rear surface of the lamp housing and connected to the low voltage electrodes of the plurality of lamps 12; And a feedback line 50 connected between the first printed circuit board 30 and the second printed circuit board 40.

Each of the plurality of lamps 12 includes a glass tube, inert gases inside the glass tube, and a high voltage electrode HIGH and a low voltage electrode LOW disposed at both ends of the glass tube. Inert gas is filled in the glass tube, and phosphor is coated on the inner wall of the glass tube.

As such, the plurality of lamps 12 are housed in the lamp housing 20. At this time, the high pressure electrode HIGH of the plurality of lamps 12 is disposed on one side of the lamp housing 20, and the low pressure electrode LOW of the plurality of lamps 12 is disposed on the other side of the lamp housing 20. In addition, a first printed circuit board 30 on which the inverter unit 32 is mounted is disposed on one rear surface of the lamp housing 20, and a second printed circuit board 34 is disposed on the other rear surface. Accordingly, the high voltage electrode HIGH of each of the plurality of lamps 12 is connected to the inverter unit 32 through the first printed circuit board 30 through the relatively short high voltage line 36. The low voltage electrode LOW of each of the lamps 12 is connected to the second printed circuit board 40.

The inverter unit 32 is mounted on the first printed circuit board 30, and first connectors 34 to which the high voltage line 36 is connected are installed at one edge thereof.

The inverter unit 32 converts the DC power supplied from the outside into a high voltage AC waveform by using switching elements (not shown) and supplies the DC power to the high voltage electrodes HIGH of the plurality of lamps 12. That is, the inverter unit 32 generates a high voltage AC waveform and supplies the generated high voltage AC waveform to the high voltage electrodes HIGH of the plurality of lamps 12 through the first connector 34. The inverter unit 32 is a first printed circuit board adjacent to the high voltage electrode HIGH of the lamps 12 in order to shorten the length of the high voltage line 36 connected to the high voltage electrode HIGH of the lamps 12. It is mounted on 30.

On the second printed circuit board 40, the second connectors 44 connected to the low voltage lines 46 connected to the low voltage electrodes LOW of the plurality of lamps 12 are installed, and the plurality of lamps 12 A current detection circuit (not shown) for detecting the tube current is mounted. In addition, a common voltage source for supplying the common voltage GND to the low voltage electrodes LOW of the plurality of lamps 12 is mounted on the second printed circuit board 40 through the second connector 44.

The current detection circuit detects the tube current of the lamps 12 when the lamps 12 are driven, and supplies a feedback signal corresponding to the detected tube current to the inverter unit 32 through the feedback line 50.

In the drive device of the conventional backlight unit as described above, the inverter unit 32 generates a high-voltage AC waveform as shown in FIG. 3 to the high voltage electrode HIGH of the lamps 12 through the high voltage line 36. And a feedback signal is supplied through the feedback line 50 from the low voltage electrode LOW of the lamps 12. Accordingly, when each of the plurality of lamps 12 is applied to the high-voltage electrode (HIGH) high-voltage AC waveform supplied from the inverter unit 32, electrons are emitted from the high-voltage electrode (HIGH) to inert gases in the glass tube And the amount of electrons increases exponentially. As the current flows inside the glass tube by the increased electrons, energy is generated as the inert gas (Ar. Ne) is excited by the electrons, and ultraviolet rays are emitted while the energy excites mercury. This ultraviolet light impinges on the luminescent phosphor applied to the inner wall of the glass tube to emit visible light.

In the driving apparatus of the conventional backlight unit, heat 60 is generated by driving the inverter unit 32 when the plurality of lamps 12 are driven. The heat 60 generated when the inverter unit 32 is driven increases the temperature of the high voltage electrode region of the plurality of lamps 12. At the same time, the high voltage electrode HIGH of the plurality of lamps 12 when the plurality of lamps 12 are driven, due to the load of the high-voltage AC waveform from the inverter unit 32, as shown in FIG. The temperature 62 of the electrode HIGH portion is increased to be relatively higher than the temperature of the low voltage electrode LOW portion. As a result, the mercury 14 of the relatively high temperature HIGH portion injected into each of the plurality of lamps 12 moves toward the low temperature region of the low temperature electrode LOW. Accordingly, the mercury 14 moves to the low pressure electrode LOW region due to the temperature of the high pressure electrode HIGH region of each of the plurality of lamps 12, and thus, at the high pressure electrode HIGH region of the plurality of lamps 12. Pink discharge will occur. Here, the pink discharge is discharged between the inert gas injected into each of the plurality of lamps 12, that is, argon (Ne) and neon (Ne) as the mercury vapor pressure of the high voltage electrode (HIGH) portion decreases. It is a phenomenon that occurs. As such, when pink discharge is generated in the plurality of lamps 12, mercury that generates ultraviolet rays is considered to be extinguished, and thus the life of the lamp 12 is typically regarded as an end state.

In the conventional drive unit of the backlight unit, since the inverter unit 32 is disposed adjacent to the plurality of lamps 12, the heat 60 and the inverter unit 32 generated when the inverter unit 32 is driven. Due to the temperature 62 of the high voltage electrode (HIGH) portion of the plurality of lamps 12 by the load of the high-voltage AC waveform supplied from the high voltage electrode of the plurality of lamps 12 as shown in FIG. The temperature deviation between the HIGH) region and the low voltage electrode (LOW) region occurs. Due to the temperature deviation TB between the high voltage electrode HIGH and the low voltage electrode LOW of the plurality of lamps 12, the brightness of the plurality of lamps 12 may vary. In addition, in the driving apparatus of the conventional backlight unit, pink discharge occurs in the lamp due to the temperature of the high voltage electrode HIGH of the plurality of lamps 12 described above.

On the other hand, the driving device of the conventional backlight unit used in the liquid crystal display for a television recently turned on / off a plurality of lamps 12 at regular intervals in order to improve the motion blur or peak brightness, which is a weak point of the liquid crystal display for a television. The scanning method or the method of adjusting the tube current supplied to the plurality of lamps 12 within a predetermined range is used. Since the load of the driving device of the conventional backlight unit used in the liquid crystal display for a television also occurs in the high voltage electrode (HIGH) of the plurality of lamps 12, the temperature imbalance of the lamps 12 described above is reduced. Will occur.

Accordingly, it is an object of the present invention to provide a drive unit of a backlight unit capable of making the temperature deviation of the lamp uniform.

In addition, another object of the present invention is to provide a driving unit of the backlight unit to improve the life of the lamp by making the temperature deviation of the lamp uniform.

In order to achieve the above object, a driving apparatus of a backlight unit according to an exemplary embodiment of the present invention includes a lamp having a high voltage electrode to which an AC signal is applied and a low voltage electrode to which a common voltage is applied, and generating the AC signal. And a signal transmission cable for transmitting an AC signal from the inverter to the high voltage electrode of the lamp.

The driving unit of the backlight unit may include a lamp housing accommodating the lamp, a first printed circuit board disposed on one rear surface of the lamp housing, to which the low voltage electrode of the lamp is connected, and to which the inverter is mounted; And a second printed circuit board disposed on the other rear surface to which the high voltage electrode of the lamp is connected.

In the driving apparatus of the backlight unit, the signal transmission cable is connected between the first and second printed circuit boards.

The driving unit of the backlight unit may further include a current detector mounted on the first printed circuit board and connected to the low voltage electrode to supply a feedback signal corresponding to the tube current of the lamp to the inverter. .

In the driving apparatus of the backlight unit, the inverter may vary the AC signal in response to a feedback signal from the current detector.

According to an embodiment of the present invention, a driving unit of a backlight unit includes a lamp having a temperature biased on one side and a temperature having a relatively low temperature on the other side, and an inverter generating an AC signal for driving the lamp. The temperature of the lamp is characterized in that it is located close to the other side of the lamp having a relatively low temperature.

The driving unit of the backlight unit may include a lamp housing accommodating the lamp, a first printed circuit board disposed at one rear surface of the lamp housing, to which the other side of the lamp is connected, and to which the inverter is mounted, and the other side of the lamp housing. A second printed circuit board disposed on a rear surface of the second printed circuit board to which one side of the lamp is connected, and a signal transmission cable connected between the first and second printed circuit boards to transfer an AC signal from the inverter to one side of the lamp; It is characterized by further comprising.

And a current detector mounted on the first printed circuit board in the driving unit of the backlight unit and connected to the other side to supply a feedback signal corresponding to the tube current of the lamp to the inverter.

In the driving apparatus of the backlight unit, the inverter may vary the AC signal in response to a feedback signal from the current detector.

In the driving apparatus of the backlight unit, the other side of the lamp is a high voltage electrode to which the AC signal is applied, and one side of the lamp is characterized in that the low voltage electrode to which a common voltage is applied.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 6 to 9.

Referring to FIG. 6, a driving apparatus of a backlight unit according to an embodiment of the present invention includes a plurality of lamps 112 including a high voltage electrode HIGH and a low voltage electrode LOW and arranged side by side at predetermined intervals. A backlight unit including a lamp housing 120 accommodating a plurality of lamps 112, a diffuser (not shown) covering a front surface of the lamp housing and a plurality of optical sheets (not shown) stacked on the diffuser plate; An inverter unit 132 disposed at one rear surface of the lamp housing 120 so as to be adjacent to the low voltage electrode portions of each of the plurality of lamps 112 and generating a high-voltage AC waveform for driving the plurality of lamps 112; ; A first printed circuit board 130 disposed on one rear surface of the lamp housing 120 and mounted with an inverter unit 132; A second printed circuit board 140 disposed on the other rear surface of the lamp housing and connected to the high voltage electrodes of the plurality of lamps 112; A cable 150 connected between the first printed circuit board 130 and the second printed circuit board 140 to supply the high-voltage AC waveform from the inverter unit 132 to the second printed circuit board 140. do.

Each of the lamps 112 includes a glass tube, inert gases inside the glass tube, and a high voltage electrode HIGH and a low voltage electrode LOW disposed at both ends of the glass tube. Inert gas is filled in the glass tube, and phosphor is coated on the inner wall of the glass tube.

As such, the plurality of lamps 112 is received in the lamp housing 120. At this time, the low pressure electrode LOW of the plurality of lamps 112 is disposed at one side of the lamp housing 120, and the high pressure electrode HIGH of the plurality of lamps 12 is disposed at the other side. In addition, a first printed circuit board 130 on which the inverter unit 132 is mounted is disposed on one rear surface of the lamp housing 120, and a second printed circuit board 134 is disposed on the other rear surface of the lamp housing 120. Accordingly, the low voltage electrode LOW of each of the plurality of lamps 112 is connected to the first printed circuit board 130 through a low voltage line 136 having a relatively short length, and each of the plurality of lamps 112 The high voltage electrode HIGH is connected to the inverter unit 132 of the first printed circuit board 130 through the second printed circuit board 140 and the cable 150.

On the first printed circuit board 130, first connectors 134 are connected to the low voltage lines 136 connected to the low voltage electrodes LOW of the plurality of lamps 112, and the plurality of lamps 112 may be connected. A current detection circuit and an inverter 132 (not shown) for detecting the tube current are mounted. In addition, a common voltage source for supplying the common voltage GND to the low voltage electrodes LOW of the plurality of lamps 112 is mounted on the first printed circuit board 130 through the first connector 134. Here, the current detection circuit detects the tube current of the lamps 112 when the lamps 112 are driven, and transmits a feedback signal corresponding to the detected tube current through the internal wiring of the first printed circuit board 130. 132).

The inverter unit 132 converts the DC power supplied from the outside into a high voltage AC waveform by using switching devices (not shown) and supplies the DC power to the high voltage electrodes HIGH of the plurality of lamps 112. That is, the inverter unit 132 generates an AC waveform of high pressure and supplies the generated AC waveform of the high voltage to the second printed circuit board 140 through the cable 150. In addition, the inverter unit 132 may vary the magnitude of the high-voltage AC waveform in response to a feedback signal from the current detector mounted on the first printed circuit board 130.

Second connectors 44 are provided on the second printed circuit board 140 to which the high voltage line 146 connected to the high voltage electrodes HIGH of the plurality of lamps 112 is connected. The second connector 44 is supplied with a high-pressure AC waveform supplied to the second printed circuit board 140 through the cable 150. Accordingly, the high voltage AC waveform generated by the inverter unit 132 of the first printed circuit board 130 is supplied to the second printed circuit board 140 through the cable 150, and the second printed circuit board ( The high voltage AC waveform supplied to the 140 is supplied to the high voltage electrode HIGH of the plurality of lamps 112 through the second connector 144.

As described above, the inverter unit 132 in the driving apparatus of the backlight unit according to the embodiment of the present invention generates a high-voltage AC waveform as shown in FIG. 7 via the cable 150 to the second printed circuit board ( 140). Accordingly, when each of the plurality of lamps 112 is applied to the high voltage electrode HIGH by applying a high-voltage AC waveform supplied from the inverter unit 132 through the second connector 144 of the second printed circuit board 140. The electrons are emitted from the high voltage electrode (HIGH) and collide with the inert gases in the glass tube to increase the amount of electrons exponentially. As the current flows inside the glass tube by the increased electrons, energy is generated as the inert gas (Ar. Ne) is excited by the electrons, and ultraviolet rays are emitted while the energy excites mercury. This ultraviolet light impinges on the luminescent phosphor applied to the inner wall of the glass tube to emit visible light.

In the driving apparatus of the backlight unit according to the exemplary embodiment of the present invention, heat 160 is generated by driving the inverter unit 132 when the plurality of lamps 112 are driven. The heat 160 generated when the inverter unit 132 is driven increases the temperature of the low voltage electrode LOW region of the plurality of lamps 112. At the same time, when driving the plurality of lamps 112, the high voltage electrode HIGH part has a temperature 162 rising due to the load of the high-voltage AC waveform supplied from the inverter unit 132. As a result, as shown in FIG. 8, the temperature deviation between the high voltage electrode HIGH and the low voltage electrode LOW of each of the plurality of lamps 112 becomes the same. Accordingly, as a result of measuring at the back of the backlight unit, the temperature generated when the plurality of lamps 112 are driven is uniform as shown in FIG. 9.

As described above, the driving apparatus of the backlight unit according to the exemplary embodiment of the present invention has the inverter unit 132 for driving the plurality of lamps 112 adjacent to the low voltage electrodes LOW of the plurality of lamps 112. By arranging the rear surface of the lamp housing 120, the temperature deviation between the portions of the high voltage electrode HIGH and the low voltage electrode LOW of each of the plurality of lamps 112 may be uniform. Accordingly, the driving apparatus of the backlight unit according to the embodiment of the present invention prevents the movement of the mercury injected into each of the plurality of lamps 112 by equalizing the temperature deviation of each of the plurality of lamps 112. Done. Accordingly, the driving apparatus of the backlight unit according to the embodiment of the present invention prevents the movement of mercury injected into each of the lamps 112 by making the temperature deviations of the plurality of lamps 112 uniform, thereby moving the mercury. It can prevent the pink discharge caused by the phenomenon, which can improve the life of the lamp. Here, the pink discharge is discharged between the inert gas injected into each of the plurality of lamps 112, that is, argon (Ne) and neon (Ne), as the mercury vapor pressure of the high voltage electrode (HIGH) portion decreases. It is a phenomenon that occurs.

As described above, the driving unit of the backlight unit according to the embodiment of the present invention arranges the inverter unit adjacent to the low voltage electrodes of each of the plurality of lamps, and relatively long distances the AC waveform generated by the inverter unit By supplying the high voltage electrode in the chamber, the temperature between the low pressure electrode and the high voltage electrode of the lamp can be made uniform. Accordingly, the present invention can prevent the movement of mercury due to the temperature deviation by making the temperature deviation of the lamp uniform. Therefore, the present invention can improve the life of the lamp by preventing the pink discharge of the lamp by preventing the movement of mercury injected into the plurality of lamps.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is a plan view showing a driving device of a general backlight unit.

FIG. 2 is a rear view illustrating a driving device of the general backlight unit illustrated in FIG. 1.

3 is a view showing the heat generation of the inverter unit and the high voltage electrode of the lamp shown in FIG.

4 is a diagram illustrating mercury movement of a lamp and a temperature deviation of the lamp by a driving device of a general backlight unit.

5 is a view showing the temperature of the lamp measured on the back of the general backlight unit.

6 is a view showing a driving device of a backlight unit according to an embodiment of the present invention.

FIG. 7 is a view illustrating heat generation of the inverter unit illustrated in FIG. 6 and heat generation of the high voltage electrode of the lamp; FIG.

8 is a diagram illustrating mercury movement of a lamp and a temperature deviation of the lamp by a driving device of a backlight unit according to an exemplary embodiment of the present invention.

9 is a view showing the temperature of the lamp measured on the back of the backlight unit according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

12, 112: lamp 14: mercury

20, 120: lamp housing 30, 40, 130, 140: printed circuit board

32, 132: inverter 34, 44, 134, 144: connector

36, 146: high voltage cable 46, 136: low voltage cable

50: feedback line 150: cable

Claims (10)

A lamp having a high voltage electrode to which an AC signal is applied and a low voltage electrode to which a common voltage is applied; An inverter generating the AC signal and located close to the low voltage electrode side of the lamp; And a signal transmission cable for transmitting an AC signal from the inverter to the high voltage electrode of the lamp. The method of claim 1, A lamp housing accommodating the lamp; A first printed circuit board disposed on one rear surface of the lamp housing and connected to the low voltage electrode of the lamp and mounted with the inverter; And a second printed circuit board disposed on the other rear surface of the lamp housing to which the high voltage electrode of the lamp is connected. The method of claim 2, And said signal transmission cable is connected between said first and second printed circuit boards. The method of claim 1, And a current detector mounted on the first printed circuit board and connected to the low voltage electrode side to supply a feedback signal corresponding to the tube current of the lamp to the inverter. The method of claim 4, wherein And the inverter varies the AC signal in response to a feedback signal from the current detector. When the temperature of light emission is biased on one side and the temperature on the other side is relatively low, An inverter for generating an AC signal for driving the lamp, The inverter is a drive device of the backlight unit, characterized in that located near to the other side of the lamp the temperature is relatively low when the heat of the lamp. The method of claim 6, A lamp housing accommodating the lamp; A first printed circuit board disposed on one rear surface of the lamp housing and connected to the other side of the lamp and mounted with the inverter; A second printed circuit board disposed on the other rear surface of the lamp housing and connected to one side of the lamp; And a signal transmission cable connected between the first and second printed circuit boards to transfer an AC signal from the inverter to one side of the lamp. The method of claim 6, And a current detector mounted on the first printed circuit board and connected to the other side to supply a feedback signal corresponding to the tube current of the lamp to the inverter. The method of claim 8, And the inverter varies the AC signal in response to a feedback signal from the current detector. The method of claim 6, The other side of the lamp is a high voltage electrode to which the AC signal is applied, One side of the lamp is a driving device of a backlight unit, characterized in that the low voltage electrode to which a common voltage is applied.