KR20050097040A - Apparatus driving lamp of liquid crystal display device - Google Patents

Abstract

The present invention relates to a lamp driving device of a liquid crystal display device which reduces the price of the direct type backlight unit and makes the current distribution uniform.

The lamp driving apparatus of the liquid crystal display according to an exemplary embodiment of the present invention supplies a plurality of lamps having first and second electrodes and a high voltage AC waveform having a first phase to each of the first electrodes of the plurality of lamps. A first inverter substrate, a plurality of first capacitors connected to each of the second electrodes, and a second phase different from the first phase to each of the second electrodes of the lamps via each of the plurality of first capacitors. And a second inverter substrate for supplying a high voltage alternating current waveform having two phases in common.

According to this configuration, the present invention provides a plurality of lamps by separately supplying a high voltage alternating current waveform to the first electrode of each of the plurality of lamps and simultaneously supplying a high voltage alternating current waveform to the second electrode of each of the plurality of lamps. Not only can the current supplied to the lamps be individually controlled, but the current balance between the multiple lamps can be made uniform. In addition, the present invention can reduce the cost of the lamp driving apparatus by driving a plurality of lamps by the individual driving method and the parallel driving method.

Description

Lamp driving device of liquid crystal display device {APPARATUS DRIVING LAMP OF LIQUID CRYSTAL DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a lamp driving device of a liquid crystal display device, which reduces the price of a direct type backlight unit and makes the current distribution uniform.

In general, liquid crystal displays (hereinafter referred to as "LCDs") have tended to be increasingly wider in application due to features such as 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 displays the desired image on the screen by adjusting the transmission amount of the light beam according to the image signal applied to the control switches arranged in a matrix form.

1 and 2, a driving device of a general liquid crystal display device includes a liquid crystal panel 6 and a direct backlight unit including a plurality of lamps 12 for irradiating light to the liquid crystal panel 6. And a first inverter substrate 30 for supplying a high voltage alternating current waveform having a first phase to the first electrodes of the plurality of lamps 12 and a first phase different from the first phase to the second electrodes of the plurality of lamps 12. A second inverter substrate 40 for supplying a high voltage AC waveform having a second phase is provided.

The liquid crystal panel 6 includes a spacer (not shown) for injecting liquid crystal between the upper substrate 3 and the lower substrate 5 and for maintaining a constant gap between the upper substrate 3 and the lower substrate 5. . In the upper substrate 3 of the liquid crystal panel 6, a color filter, a common electrode, a black matrix, and the like, which are not shown, are formed. In addition, signal lines such as data lines and gate lines (not shown) are formed on the lower substrate 5 of the liquid crystal panel 6, and thin film transistors are formed at the intersections of the data lines and the gate lines. The thin film transistor switches a data signal to be transmitted from the data line toward the liquid crystal cell in response to a scan signal (gate pulse) from the gate line. The pixel electrode is formed in the pixel region between the data line and the gate line. In addition, one side of the lower substrate 5 is formed with a pad region for connecting data lines and gate lines, respectively, and in this pad region, a tape in which a driver integrated circuit for applying a driving signal to the thin film transistor is mounted. A carrier package is attached. The tape carrier package supplies data signals and scan signals to the data lines and the gate lines from the driver integrated circuit, respectively.

The upper polarizing sheet (not shown) is attached to the upper substrate 3 of the liquid crystal panel 6, and the lower polarizing sheet (not shown) is attached to the rear surface of the lower substrate 5. At this time, the upper and lower polarizing sheets serve to extend the viewing angle of the image displayed by the liquid crystal cell matrix.

The direct type backlight unit is arranged side by side, the plurality of lamps 12 for irradiating light to the liquid crystal panel 6, the bottom cover 10 for receiving the plurality of lamps 12, and the bottom cover 10 The diffusion plate 16 covering the front surface and the optical sheets 18 sequentially stacked on the diffusion plate 16 are provided.

Each of the plurality of lamps 12 includes a glass tube, inert gases inside the glass tube, and first and second electrodes provided 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.

The bottom cover 10 prevents light leakage of visible light emitted from each of the plurality of lamps 12 and reflects visible light traveling toward the side and the back of the plurality of lamps 12 toward the front surface, that is, the diffuser plate 16. This improves the efficiency of the light generated in the lamps 12.

The diffuser plate 16 allows the light emitted from the plurality of lamps 12 to propagate toward the liquid crystal panel 6 and allows it to be incident at a wide range of angles. Such a diffusion plate 16 uses a coating of a light diffusion member on both sides of a film made of a transparent resin.

The optical sheets 18 improve the efficiency of light emitted from the diffuser plate 16 to irradiate the liquid crystal panel 6.

The first inverter substrate 30 converts an inverter integrated circuit (not shown) for converting lamp driving power supplied from an external source (not shown) supplied from the outside into an AC waveform, and converts an AC waveform from the inverter integrated circuit into a high voltage AC waveform. A plurality of first transformers 34, a plurality of first output terminals 36 connected to each of the plurality of first transformers 34, and a first electrode of each of the plurality of lamps 12. A plurality of first wires 38 connected to each of the plurality of first output terminals 36 are provided.

The first inverter integrated circuit switches the switching elements (not shown) in response to a control signal supplied from the system, converts the lamp driving power supplied from the power supply device into an AC waveform and supplies it to the plurality of first transformers 34. The plurality of first transformers 34 converts the AC waveform from the first inverter integrated circuit supplied to the primary winding by the turns ratio of the primary winding and the secondary winding into an AC waveform having a high voltage. Each of the high voltage AC waveforms generated by each of the plurality of first transformers 34 is supplied to each of the first electrodes of the lamp 12 through the first output terminal 36 and the first wire 38. At this time, the AC waveform of the high voltage supplied to the first electrodes of the plurality of lamps 12 has the first phase.

The second inverter substrate 40 converts an unillustrated inverter integrated circuit which converts lamp driving power supplied from an external source (not shown) supplied from the outside into an AC waveform, and converts an AC waveform from the inverter integrated circuit into a high voltage AC waveform. A plurality of second transformers 44, a plurality of second output terminals 46 connected to each of the plurality of second transformers 44, and a second electrode of each of the plurality of lamps 12. A second wire 48 is connected and connected to each of the plurality of second output terminals 46.

The second inverter integrated circuit switches the switching elements (not shown) in response to a control signal supplied from the system, converts the lamp driving power supplied from the power supply device into an AC waveform and supplies it to the plurality of second transformers 44. The plurality of second transformers 44 converts AC waveforms from the second inverter integrated circuit supplied to the primary windings into AC waveforms of high voltage by the turns ratio of the primary windings and the secondary windings. Each of the high voltage AC waveforms generated by each of the plurality of second transformers 44 is supplied to each of the second electrodes of the lamp 12 through the second output terminal 46 and the second wire 48. At this time, the high voltage AC waveform supplied to each of the second electrodes of the plurality of lamps 12 has a second phase different from the high voltage AC waveform having a first phase supplied to the first electrodes of the plurality of lamps 12. do.

Such a lamp driving apparatus of a general liquid crystal display device turns on a plurality of lamps 12 by supplying a high voltage alternating current waveform to each of the first and second electrodes of the plurality of lamps 12 so as to turn on the liquid crystal panel 6. The light is irradiated to.

However, the lamp driving apparatus of such a general liquid crystal display device has a lamp by adding transformers 34 and 44, a switching element, and an inverter integrated circuit to individually drive each of the plurality of lamps 12 as shown in FIG. There is a problem that the price of the drive increases.

In order to reduce the increase in the price of such a lamp driving device, a lamp driving device of a liquid crystal display device which drives a plurality of lamps 12 in parallel has been proposed.

4 and 5, the lamp driving apparatus of the general parallel driving method has the same components as the lamp driving apparatus of the above-described general liquid crystal display except for the first and second inverter substrates 60 and 70. do. Accordingly, in the general parallel drive lamp driving apparatus, descriptions of other components except for the first and second inverter substrates 60 and 70 will be replaced with the above description.

The first inverter substrate 60 converts an unillustrated inverter integrated circuit which converts lamp driving power supplied from the outside not shown supplied from the outside into an alternating current waveform, and converts an alternating current waveform from the inverter integrated circuit into a high voltage alternating current waveform. Two first transformers 64, a first common line 65 commonly connected to each of the two first transformers 64, and a plurality of first connected to the first common line 65. An output terminal 66 and a plurality of first wires 68 connected to the first electrode of each of the plurality of lamps 12 and to each of the plurality of first output terminals 66 are provided.

The first inverter integrated circuit switches the switching elements (not shown) in response to a control signal supplied from the system, converts the lamp driving power supplied from the power supply device into an AC waveform and supplies it to the two first transformers 64. The two first transformers 64 convert the AC waveform from the first inverter integrated circuit supplied to the primary winding by the turns ratio of the primary winding and the secondary winding into an AC waveform of high voltage. The high voltage AC waveform generated by the two first transformers 64 is supplied to the first common line 65. The high voltage AC waveform supplied to the first common line 65 is supplied to each of the first electrodes of the plurality of lamps 12 through the plurality of first output terminals 66 and the plurality of first wires 68. At this time, the AC waveform of the high voltage supplied to the first electrodes of the plurality of lamps 12 has the first phase.

The second inverter substrate 70 converts an inverter integrated circuit (not shown) for converting lamp driving power supplied from an external source (not shown) supplied from the outside into an AC waveform, and converts an AC waveform from the inverter integrated circuit into a high voltage AC waveform. Two second transformers 74, a second common line 75 commonly connected to each of the two second transformers 74, and a plurality of second connected to the second common line 75. An output terminal 76 and a plurality of second wires 78 connected to the second electrode of each of the plurality of lamps 12 and to each of the plurality of second output terminals 76 are provided.

The second inverter integrated circuit switches the switching elements (not shown) in response to a control signal supplied from the system, converts the lamp driving power supplied from the power supply device into an AC waveform and supplies it to the two second transformers 74. The two second transformers 74 convert the AC waveform from the second inverter integrated circuit supplied to the primary winding to the AC waveform of high voltage by the turns ratio of the primary winding and the secondary winding. The high voltage AC waveform generated by the two second transformers 74 is supplied to the second common line 75. The high voltage AC waveform supplied to the second common line 75 is supplied to each of the second electrodes of the plurality of lamps 12 through the plurality of second output terminals 76 and the plurality of second wires 78. At this time, the high voltage AC waveform supplied to the second electrodes of the plurality of lamps 12 has a second phase different from the high voltage AC waveform having the first phase supplied to the first electrodes of the plurality of lamps 12. .

The lamp driving apparatus of a general parallel driving method as described above uses two first transformers 64 to supply AC voltages of high voltage to the first electrodes of the plurality of lamps 12 in common, and to provide two second voltages. By supplying a high voltage AC waveform to the second electrodes of the plurality of lamps 12 using the transformers 74, the plurality of lamps 12 are turned on to irradiate light to the liquid crystal panel 6. .

However, since the lamp driving apparatus of the general parallel driving method has a plurality of lamps 12 because the plurality of lamps 12 are commonly connected to the first and second common lines 65 and 75 to which the high voltage AC waveform is supplied. Current is concentrated toward any of the lamps 12, resulting in an uneven current balance. This unevenness of the current distribution supplied to the lamps 12 causes a difference in luminance between the plurality of lamps 12.

Accordingly, it is an object of the present invention to provide a lamp driving device of a liquid crystal display device which can reduce the price of a direct type backlight unit and make the current distribution uniform.

In order to achieve the above object, the lamp driving apparatus of the liquid crystal display according to the embodiment of the present invention comprises a plurality of lamps having first and second electrodes and a first phase on each of the first electrodes of the plurality of lamps. And a first inverter substrate for supplying a high voltage alternating current waveform, a plurality of first capacitors connected to each of the second electrodes, and a second electrode of each of the lamps via each of the plurality of first capacitors. And a second inverter substrate for supplying a high voltage AC waveform having a second phase different from the first phase in common.

In the driving device, the first inverter substrate may include a first inverter integrated circuit configured to supply a lamp driving voltage supplied from an external source to an AC waveform, and the AC waveform of the high voltage having the first phase with an AC waveform from the inverter integrated circuit. It characterized in that it comprises a plurality of first transformer to convert to.

The driving device may further include a plurality of second capacitors connected to each of the first electrodes of the plurality of lamps and connected to an output terminal of each of the plurality of first transformers.

In the driving device, the second inverter substrate may include a second inverter integrated circuit configured to supply a lamp driving voltage supplied from an external source to an AC waveform, and the high voltage having the second phase from an AC waveform from the second inverter integrated circuit. A second transformer converting into an AC waveform and a common line connected to one side of each of the plurality of first capacitors and connected to an output terminal of the second transformer are provided.

According to another exemplary embodiment of the present invention, a lamp driving apparatus of a liquid crystal display device includes a plurality of lamps having first and second electrodes and a high voltage AC waveform having a first phase at each of the first electrodes of the plurality of lamps. A first inverter substrate for supplying, a second inverter substrate for commonly supplying a high voltage AC waveform having a second phase different from the first phase to each of the second electrodes of the lamps, and on the second inverter substrate And a first pattern capacitor formed at and connected to each of the second electrodes of the plurality of lamps.

In the driving device, the first inverter substrate may include a first inverter integrated circuit configured to supply an AC waveform from a lamp driving voltage supplied from an external source, and the high voltage having the first phase in an AC waveform from the first inverter integrated circuit. And a plurality of first transformers for converting into an AC waveform.

The driving device further includes a second pattern capacitor formed on the first inverter substrate and connected to each of the first electrodes of the plurality of lamps and to an output terminal of each of the plurality of first transformers. It is done.

In the driving device, the second inverter substrate may include a second inverter integrated circuit configured to supply a lamp driving voltage supplied from an external source to an AC waveform, and the high voltage having the second phase from an AC waveform from the second inverter integrated circuit. A second transformer for converting to an AC waveform and a common line connected to one side of the first pattern capacitor and connected to the output terminal of the second transformer are characterized in that it comprises a.

In the driving apparatus, the plurality of first pattern capacitors are formed side by side to have a predetermined interval on the front surface of the second inverter substrate, and are connected to each of the second electrodes of the plurality of lamps and connected to the common line. And first common patterns formed on the rear surface of the second inverter substrate to overlap the plurality of second patterns.

In the driving apparatus, the plurality of second pattern capacitors are formed side by side to have a predetermined interval on the front surface of the first inverter substrate, and are connected to each of the first electrodes of the plurality of lamps and the plurality of first transformers. And a plurality of second patterns connected to each output terminal and a second common pattern formed on the rear surface of the first inverter substrate so as to overlap the plurality of second patterns.

The lamp driving apparatus of the liquid crystal display according to an exemplary embodiment of the present invention includes a plurality of lamps having first and second electrodes and a high voltage AC waveform having a first phase at each of the first electrodes of the plurality of lamps. A first pattern capacitor substrate having a first inverter substrate for supplying a plurality of capacitors, a plurality of capacitor patterns formed on the plurality of capacitor patterns connected to the second electrodes of the plurality of lamps, and different from the first phase via each of the plurality of capacitor patterns. And a second inverter substrate for supplying a high voltage AC waveform having a second phase in common.

In the driving device, the first inverter substrate may include a first inverter integrated circuit configured to supply an AC waveform from a lamp driving voltage supplied from an external source, and the high voltage having the first phase in an AC waveform from the first inverter integrated circuit. And a plurality of first transformers for converting into an AC waveform.

The driving device may further include a second pattern capacitor substrate having a plurality of capacitor patterns connected to a first electrode of each of the plurality of lamps and connected to an output terminal of each of the plurality of first transformers. do.

In the driving device, the second inverter substrate may include a second inverter integrated circuit configured to supply a lamp driving voltage supplied from an external source to an AC waveform, and the high voltage having the second phase from an AC waveform from the second inverter integrated circuit. And a second transformer for converting the AC waveform to the first pattern capacitor substrate.

In the driving apparatus, the first pattern capacitor substrate is formed on a front surface of the first pattern capacitor substrate, a plurality of first patterns to which a second electrode of each of the plurality of lamps is connected, and the first pattern capacitor substrate. A first common pattern formed to overlap the plurality of first patterns on a rear surface of the substrate; and a first common pattern formed on an entire surface of the first pattern capacitor substrate and commonly connected to the plurality of first patterns and connected to the second inverter substrate. And a common line to be connected.

In the driving apparatus, the second pattern capacitor substrate is formed side by side with a predetermined interval on the front surface of the second pattern capacitor substrate, and is connected to the first electrode of each of the plurality of lamps and the plurality of first transformers. And a plurality of second patterns connected to the output terminals of each of the plurality of second patterns, and a second common pattern formed to overlap the plurality of second patterns on a rear surface of the second pattern capacitor substrate.

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 15.

6 and 7, the lamp driving apparatus of the liquid crystal display according to the first embodiment of the present invention includes a liquid crystal panel (not shown) and a plurality of lamps 112 for irradiating light to the liquid crystal panel. And a first inverter substrate 130 for supplying a high voltage alternating current waveform having a first phase to the first electrode of each of the plurality of lamps 112 and the plurality of lamps 112. The second inverter substrate 140 for supplying a high voltage AC waveform having a second phase different from the first phase to the second electrode in common, and the second inverter substrate 140 mounted on the second inverter substrate 140, A plurality of first ballast capacitors Cb1 connected to each of the two electrodes is provided.

The description of the liquid crystal panel and the direct type backlight unit will be replaced with the description of FIG. 1.

The first inverter substrate 130 is an inverter integrated circuit (not shown) for converting lamp driving power supplied from an external source (not shown) supplied from the outside into an AC waveform, and an AC waveform from the inverter integrated circuit is converted into a high voltage AC waveform. A plurality of first transformers 134, a plurality of first output terminals 136 connected to each of the plurality of first transformers 134, and a first electrode of each of the plurality of lamps 112. A plurality of first wires 138 connected to each of the plurality of first output terminals 136 are provided.

The first inverter integrated circuit switches the switching elements (not shown) in response to a control signal supplied from the system, converts the lamp driving power supplied from the power supply device into an AC waveform and supplies it to the plurality of first transformers 134. The plurality of first transformers 134 converts the AC waveform from the first inverter integrated circuit supplied to the primary winding by the turns ratio of the primary winding and the secondary winding into an AC waveform having a high voltage. Each of the high voltage AC waveforms generated by each of the plurality of first transformers 134 is supplied to each of the first electrodes of the lamp 112 through the first output terminal 136 and the first wire 138. At this time, the high voltage AC waveform supplied to the first electrodes of the plurality of lamps 112 has a first phase. The first inverter substrate 130 drives the plurality of lamps 112 individually using the same number of first transformers 134 as the plurality of lamps 112. Accordingly, the first inverter substrate 130 individually controls the amount of current supplied to the first electrode of each of the plurality of lamps 112.

The second inverter substrate 140 converts an inverter integrated circuit (not shown) for converting lamp driving power supplied from an external source (not shown) supplied from the outside into an AC waveform, and converts an AC waveform from the inverter integrated circuit into a high voltage AC waveform. Two second transformers 144, a common line 145 commonly connected to each of the two second transformers 144, and a plurality of second output terminals connected to the common line 145 ( 146 and a plurality of second wires 148 connected to a second electrode of each of the plurality of lamps 112 and to each of the plurality of second output terminals 146. In addition, the plurality of first ballast capacitors Cb1 is connected between each of the plurality of second output terminals 146 and the common line 145.

The second inverter integrated circuit switches the switching elements (not shown) in response to a control signal supplied from the system, converts the lamp driving power supplied from the power supply device into an AC waveform and supplies it to the two second transformers 144. The two second transformers 144 convert the AC waveform from the second inverter integrated circuit supplied to the primary winding by the turns ratio of the primary winding and the secondary winding into an AC waveform having a high voltage. The high voltage AC waveform generated by the two second transformers 144 is supplied to the common line 145. The high voltage alternating current waveform supplied to the common line 145 is connected to the plurality of lamps 112 through a plurality of first ballast capacitors Cb1, a plurality of second output terminals 146, and a plurality of second wires 148. Supplied to each of the second electrodes. At this time, the high voltage AC waveform supplied to the second electrodes of the plurality of lamps 112 has a second phase different from the high voltage AC waveform having the first phase supplied to the first electrodes of the plurality of lamps 112. . Here, the first phase and the second phase have a phase difference of 180 degrees.

Each of the plurality of first ballast capacitors Cb1 balances the current supplied to each of the plurality of lamps 112 through the common line 145. Accordingly, the plurality of first ballast capacitors Cb1 prevents uneven luminance between the lamps 112 by making the current balance between the plurality of lamps 112 uniform.

The second inverter substrate 140 drives two lamps 112 in parallel using two transformers 144. Accordingly, the second inverter substrate 140 supplies a high voltage AC waveform to the second electrode of each of the plurality of lamps 112 commonly connected to the common line 145.

As described above, the lamp driving apparatus of the liquid crystal display according to the first exemplary embodiment of the present invention includes a second inverter substrate 140 connected in parallel to a second electrode of the plurality of lamps 112 and a plurality of lamps 112. The plurality of lamps 112 are turned on by using the first inverter substrate 130 individually connected to the first electrode of FIG. Accordingly, the lamp driving apparatus of the liquid crystal display according to the first exemplary embodiment of the present invention controls two second transformers 144 and two second transformers 144 on the second inverter substrate 140 connected in parallel to the lamps 112. By reducing the number of lamps 112 by increasing the number of lamps 112 and mounting the switching element and the inverter integrated circuit into a single unit, the cost reduction effect can be enhanced. The plurality of lamps 112 are supplied to each of the plurality of lamps 112 by mounting a plurality of first transformers 134, switching elements for controlling the same, and inverter integrated circuits on the first inverter substrate 130 individually connected to the lamps 112. The current can be controlled individually.

Therefore, the lamp driving apparatus of the liquid crystal display according to the first embodiment of the present invention can individually control the current supplied to each of the plurality of lamps 112, and by using the plurality of first ballast capacitors Cb1. The current distribution between the lamps 112 can be made uniform.

Meanwhile, the lamp driving apparatus of the liquid crystal display according to the first exemplary embodiment of the present invention includes a plurality of first transformers 134 and a plurality of first output terminals connected to each other as illustrated in FIGS. 8 and 9. It further comprises a second ballast capacitor (Cb2) of.

Each of the second ballast capacitors Cb2 equalizes the current balance of the high voltage AC waveform supplied from each of the plurality of first transformers 134 to each of the plurality of lamps 112 using LC resonance.

10 and 11, a lamp driving apparatus of a liquid crystal display according to a second exemplary embodiment of the present invention includes a liquid crystal panel (not shown) and a plurality of lamps 112 for irradiating light to the liquid crystal panel. And a first inverter substrate 130 for supplying a high voltage alternating current waveform having a first phase to the first electrode of each of the plurality of lamps 112 and the plurality of lamps 112. A second inverter substrate 140 for supplying a high voltage AC waveform having a second phase different from the first phase to the second electrode in common, and a plurality of lamps 112 formed on the second inverter substrate 140 A plurality of pattern capacitors Cp is connected to each second electrode.

The lamp driving apparatus of the liquid crystal display according to the second exemplary embodiment of the present invention may drive the lamp of the liquid crystal display according to the first exemplary embodiment of the present invention illustrated in FIG. 6 except for the plurality of first pattern capacitors Cp1. Since the same as the device, the description of the liquid crystal panel, the direct type backlight unit, and the first and second inverter substrates 130 and 140 will be replaced with the description of the first embodiment of the present invention.

As illustrated in FIGS. 11 and 12, the plurality of first pattern capacitors Cp1 are formed to have a predetermined area on the front surface of the second inverter substrate 140 and are connected to the common line 145. A plurality of patterns 150 connected to each of the second output terminals 146 and a common pattern 152 formed to overlap the plurality of patterns 150 are formed on a rear surface of the second inverter substrate 140.

The second inverter substrate 140 has a thickness of crystal to have a predetermined dielectric constant?.

Each of the plurality of patterns 150 is formed to have a predetermined area S on the front surface of the second inverter substrate 140 to have a predetermined interval. One side of the plurality of patterns 150 is connected to the common line 145 and the other side is connected to the second output terminal 146.

The common pattern 152 is formed on the rear surface of the second inverter substrate 140 to overlap the plurality of patterns 150. The common pattern 140 is connected to the ground voltage source GND.

The liquid crystal display according to the first exemplary embodiment of the present invention is configured by the capacitance Cp generated between each of the plurality of patterns 150 overlapping the common pattern 155. It serves as a ballast capacitor (Cb) of the lamp driving device of. At this time, the value of the capacitance Ca generated in each of the plurality of first pattern capacitors Cp1 is equal to the area S of the plurality of patterns 150 and the distance d between the common pattern 152 and the plurality of patterns 150. The value divided by) is multiplied by the dielectric constant epsilon of the second inverter substrate 140. To this end, the area of each of the plurality of patterns 150 overlapping the common pattern 152 is set to have a capacitance value Cp for uniformizing the current balance of the plurality of lamps 112.

As such, the lamp driving apparatus of the liquid crystal display according to the second exemplary embodiment of the present invention includes a second inverter substrate 140 connected in parallel to a second electrode of the plurality of lamps 112 and a plurality of lamps 112. The plurality of lamps 112 are turned on by using the first inverter substrate 130 individually connected to the first electrode of FIG. Accordingly, the lamp driving device of the liquid crystal display according to the second exemplary embodiment of the present invention controls two second transformers 144 and two second transformers 144 on the second inverter substrate 140 connected in parallel to the lamps 112. The switching elements and inverter integrated circuits are integrated into a single unit, and a plurality of first pattern capacitors Cp1 are formed on the second inverter substrate 140, so that the larger the number of lamps 112, the higher the cost reduction effect. There is; The plurality of lamps 112 are supplied to each of the plurality of lamps 112 by mounting a plurality of first transformers 134, switching elements for controlling the same, and inverter integrated circuits on the first inverter substrate 130 individually connected to the lamps 112. The current can be controlled individually.

Therefore, the lamp driving apparatus of the liquid crystal display according to the second embodiment of the present invention can individually control the current supplied to each of the plurality of lamps 112, and by using the plurality of first pattern capacitors Cp1. The current distribution between the lamps 112 can be made uniform.

Meanwhile, the lamp driving apparatus of the liquid crystal display according to the second exemplary embodiment of the present invention includes a plurality of first transformers 134 and a plurality of first output terminals connected to each other as illustrated in FIGS. 8 and 9. Further includes a second pattern capacitor Cb2.

Each of the second pattern capacitors Cp2 is formed on the first inverter substrate 130 in the same structure as the first pattern capacitor Cp1 as illustrated in FIGS. 11 and 12. Since the structure of the second pattern capacitor Cp2 is the same as that of the first pattern capacitor Cp1, the detailed description will be replaced with the description of the first pattern capacitor Cp1.

The plurality of second pattern capacitors Cp2 may play the same role as the plurality of first pattern capacitors Cp1, and may include a plurality of lamps from each of the plurality of transformers 134 of the first inverter substrate 130. 112) The current balance supplied to each is made uniform. Accordingly, the first inverter substrate 130 individually controls the current supplied to each of the plurality of lamps 112 and the current supplied to the lamps 112 using the plurality of second pattern capacitors Cp2. Make the balance even.

Referring to FIG. 13, a lamp driving apparatus of a liquid crystal display according to a third exemplary embodiment of the present invention includes a liquid crystal panel (not shown) and a plurality of lamps 112 for irradiating light to the liquid crystal panel. The first inverter substrate 130 for supplying a high voltage AC waveform having a first phase to the light unit, the first electrodes of each of the plurality of lamps 112, and the second electrode of each of the plurality of lamps 112. Between the second inverter substrate 140 and the second inverter substrate 140 and the second electrodes of the plurality of lamps 112 to supply a high voltage AC waveform having a second phase different from the first phase in common. A pattern capacitor substrate 155 to be connected is provided.

The lamp driving apparatus of the liquid crystal display according to the second exemplary embodiment of the present invention is the liquid crystal according to the first exemplary embodiment of the present invention shown in FIG. 6 except for the second inverter substrate 140 and the pattern capacitor substrate 155. Since it is the same as the lamp driving device of the display device, the description of the liquid crystal panel, the direct type backlight unit, and the first inverter substrate 130 will be replaced with the description of the first embodiment of the present invention.

The second inverter substrate 140 converts an inverter integrated circuit (not shown) for converting lamp driving power supplied from an external source (not shown) supplied from the outside into an AC waveform, and converts an AC waveform from the inverter integrated circuit into a high voltage AC waveform. Two second transformers 144 and a second output terminal 146 are provided at each of the two second transformers 144.

The second inverter integrated circuit switches the switching elements (not shown) in response to a control signal supplied from the system, converts the lamp driving power supplied from the power supply device into an AC waveform and supplies it to the two second transformers 144. The two second transformers 144 convert the AC waveform from the second inverter integrated circuit supplied to the primary winding by the turns ratio of the primary winding and the secondary winding into an AC waveform having a high voltage. The high voltage AC waveform generated by the two second transformers 144 is supplied to the pattern capacitor substrate 155 through the second output terminal 146 and the second wire 148.

The pattern capacitor substrate 155 may have a common line 157 connected to the second wire 148 and a plurality of patterns formed to have a predetermined area on the front surface of the substrate 155 to be connected to the common line 145. 160, a plurality of common patterns 162 formed on the rear surface of the substrate 155 to overlap the plurality of patterns 160, a plurality of common patterns 162, and a plurality of patterns 160, respectively. The hole 164 formed in the 155 is provided. In this case, the pattern capacitor substrate 155 is installed inside the bottom cover 110 and is connected to the second electrodes of the plurality of lamps 112.

The pattern capacitor substrate 155 has a thickness of crystal to have a predetermined dielectric constant ??.

Each of the plurality of patterns 160 is formed to have a predetermined area S on the front surface of the substrate 155 to have a predetermined interval. One side of the plurality of patterns 160 is connected to the common line 145.

The common pattern 162 is formed on the rear surface of the substrate 155 to overlap the plurality of patterns 160. This common pattern 162 is connected to the ground voltage source GND.

The second electrode of each of the plurality of lamps 112 is connected to each of the plurality of patterns 160 through the hole 164 formed on the substrate 155. In this case, each of the plurality of lamps 112 passes through the plurality of common patterns 162 and is connected to each of the plurality of patterns 160.

The pattern capacitor substrate 155 is a ballast of the lamp driving apparatus of the liquid crystal display according to the first exemplary embodiment of the present invention due to capacitance generated between each of the plurality of patterns 160 overlapping the common pattern 162. It serves as a capacitor (Cb). In this case, the capacitance value is obtained by dividing the area S of the plurality of patterns 160 by the distance d between the common pattern 162 and the plurality of patterns 160. Is multiplied. To this end, an area of each of the plurality of patterns 160 overlapping the common pattern 162 is set to have a capacitance value for making the current balance of the plurality of lamps 112 uniform.

As such, the lamp driving apparatus of the liquid crystal display according to the third exemplary embodiment of the present invention includes a second inverter substrate 140 connected in parallel to a second electrode of the plurality of lamps 112 and a plurality of lamps 112. The plurality of lamps 112 are turned on by using the first inverter substrate 130 individually connected to the first electrode of FIG. Accordingly, the lamp driving apparatus of the liquid crystal display according to the third exemplary embodiment of the present invention controls two second transformers 144 and two second transformers 144 on the second inverter substrate 140 connected in parallel to the lamps 112. It is possible to increase the cost reduction effect as the number of the lamps 112 increases as the number of lamps 112 is increased by unifying the switching elements and the inverter integrated circuit into a single unit, and forming a pattern capacitor on the pattern capacitor substrate 155; The plurality of lamps 112 are supplied to each of the plurality of lamps 112 by mounting a plurality of first transformers 134, switching elements for controlling the same, and inverter integrated circuits on the first inverter substrate 130 individually connected to the lamps 112. The current can be controlled individually.

Therefore, the lamp driving apparatus of the liquid crystal display according to the third embodiment of the present invention can individually control the current supplied to each of the plurality of lamps 112, and the lamps 112 using the pattern capacitor Cp. It is possible to make the distribution of current between them uniform.

Meanwhile, the lamp driving apparatus of the liquid crystal display according to the third exemplary embodiment of the present invention may further include a pattern capacitor substrate connected between the first inverter substrate 130 and the first electrodes of the plurality of lamps 112. have.

As described above, the lamp driving apparatus of the liquid crystal display according to the embodiment of the present invention supplies a high voltage AC waveform to each of the first electrodes of each of the plurality of lamps individually and to the second electrode of each of the plurality of lamps. By supplying a high voltage alternating current waveform in common, not only can the current supplied to the plurality of lamps be individually controlled, but also the current balance between the plurality of lamps can be made uniform.

In addition, the lamp driving apparatus of the liquid crystal display according to the exemplary embodiment of the present invention can reduce the price of the lamp driving apparatus by driving a plurality of lamps by an individual driving method and a parallel driving method.

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 cross-sectional view schematically showing a lamp driving device of a general liquid crystal display device.

FIG. 2 shows a first and a second inverter substrate for driving the lamps shown in FIG. 1; FIG.

3 shows transformers connected to the lamps shown in FIG.

4 shows another form of the first and second inverter substrates for driving the lamps shown in FIG.

FIG. 5 shows transformers connected to the lamps shown in FIG. 4. FIG.

6 is a view showing a lamp driving device of the liquid crystal display according to the first embodiment of the present invention.

FIG. 7 shows transformers connected to the lamps shown in FIG. 6. FIG.

8 is a view showing a lamp driving apparatus of another liquid crystal display according to the first embodiment of the present invention.

9 shows transformers connected to the lamps shown in FIG. 8; FIG.

10 is a view showing a lamp driving apparatus of the liquid crystal display according to the second embodiment of the present invention.

FIG. 11 is a view showing a second inverter substrate shown in FIG. 10. FIG.

FIG. 12 is a cross-sectional view taken along a line II-XII 'of FIG. 11. FIG.

13 is a view showing a lamp driving apparatus of another liquid crystal display according to a second embodiment of the present invention.

14 is a view showing a lamp driving apparatus of the liquid crystal display according to the third embodiment of the present invention.

FIG. 15 shows the pattern capacitor substrate shown in FIG. 14; FIG.

<Description of Symbols for Main Parts of Drawings>

3: upper substrate 5: lower substrate

6: liquid crystal panel 10, 110: bottom cover

12, 112: lamp 16: diffusion plate

18: optical sheet 30, 130: first inverter substrate

40, 140: second inverter substrate 34, 44, 134, 144: transformer

145, 157: common line 150, 160: pattern

152, 162: common pattern 155: pattern capacitor substrate

Claims (16)

A plurality of lamps having first and second electrodes, A first inverter substrate for supplying a high voltage AC waveform having a first phase to each of the first electrodes of the plurality of lamps; A plurality of first capacitors connected to each of the second electrodes; And a second inverter substrate for commonly supplying a high voltage AC waveform having a second phase different from the first phase to each of the second electrodes of the lamps via each of the plurality of first capacitors. A drive device for a liquid crystal display device. The method of claim 1, The first inverter substrate, A first inverter integrated circuit which supplies a lamp driving voltage supplied from an external source to an AC waveform; And a plurality of first transformers for converting an AC waveform from the inverter integrated circuit into the high voltage AC waveform having the first phase. The method of claim 2, And a plurality of second capacitors connected to each of the first electrodes of the plurality of lamps and connected to an output terminal of each of the plurality of first transformers. The method of claim 1, The second inverter substrate, A second inverter integrated circuit which supplies a lamp driving voltage supplied from an external source to an AC waveform; A second transformer for converting an AC waveform from said second inverter integrated circuit into said high voltage AC waveform having said second phase; And a common line connected to one side of each of the plurality of first capacitors and connected to an output terminal of the second transformer. A plurality of lamps having first and second electrodes, A first inverter substrate for supplying a high voltage AC waveform having a first phase to each of the first electrodes of the plurality of lamps; A second inverter substrate for commonly supplying a high voltage AC waveform having a second phase different from the first phase to each of the second electrodes of the lamps; And a first pattern capacitor formed on the second inverter substrate and connected to each of the second electrodes of the plurality of lamps. The method of claim 5, The first inverter substrate, A first inverter integrated circuit which supplies a lamp driving voltage supplied from an external source to an AC waveform; And a plurality of first transformers for converting an AC waveform from the first inverter integrated circuit into the high voltage AC waveform having the first phase. The method of claim 6, And a second pattern capacitor formed on the first inverter substrate and connected to each of the first electrodes of the plurality of lamps and to an output terminal of each of the plurality of first transformers. Lamp drive of the device. The method of claim 6, The second inverter substrate, A second inverter integrated circuit which supplies a lamp driving voltage supplied from an external source to an AC waveform; A second transformer for converting an AC waveform from said second inverter integrated circuit into said high voltage AC waveform having said second phase; And a common line connected to one side of the first pattern capacitor and connected to an output terminal of the second transformer. The method of claim 8, The plurality of first pattern capacitors; A plurality of first patterns formed side by side with a predetermined interval on a front surface of the second inverter substrate, connected to each of the second electrodes of the plurality of lamps, and connected to the common line; And a first common pattern formed on a rear surface of the second inverter substrate so as to overlap the plurality of second patterns. The method of claim 7, wherein The plurality of second pattern capacitors; A plurality of second patterns formed side by side with a predetermined interval on the front surface of the first inverter substrate, connected to each of the first electrodes of the plurality of lamps, and connected to an output terminal of each of the plurality of first transformers; Field, And a second common pattern formed on the rear surface of the first inverter substrate so as to overlap the plurality of second patterns. A plurality of lamps having first and second electrodes, A first inverter substrate for supplying a high voltage AC waveform having a first phase to each of the first electrodes of the plurality of lamps; A first pattern capacitor substrate having a plurality of capacitor patterns connected to each of the second electrodes of the plurality of lamps; And a second inverter substrate for commonly supplying a high voltage AC waveform having a second phase different from the first phase via each of the plurality of capacitor patterns. The method of claim 11, The first inverter substrate, A first inverter integrated circuit which supplies a lamp driving voltage supplied from an external source to an AC waveform; And a plurality of first transformers for converting an AC waveform from the first inverter integrated circuit into the high voltage AC waveform having the first phase. The method of claim 12, And a second pattern capacitor substrate having a plurality of capacitor patterns connected to a first electrode of each of the plurality of lamps and connected to an output terminal of each of the plurality of first transformers. Lamp drive. The method of claim 11, The second inverter substrate, A second inverter integrated circuit which supplies a lamp driving voltage supplied from an external source to an AC waveform; And a second transformer for converting the AC waveform from the second inverter integrated circuit into the high voltage AC waveform having the second phase and supplying the AC waveform to the first pattern capacitor substrate. Device. The method of claim 14, The first pattern capacitor substrate; A plurality of first patterns formed on a front surface of the first pattern capacitor substrate and connected to a second electrode of each of the plurality of lamps; A first common pattern formed on a rear surface of the first pattern capacitor substrate so as to overlap the plurality of first patterns; And a common line formed on an entire surface of the first pattern capacitor substrate and commonly connected to the plurality of first patterns and connected to the second inverter substrate. The method of claim 13, The second pattern capacitor substrate; A plurality of first terminals formed side by side with a predetermined interval on the front surface of the second pattern capacitor substrate and connected to a first electrode of each of the plurality of lamps and to an output terminal of each of the plurality of first transformers; 2 patterns, And a second common pattern formed on a rear surface of the second pattern capacitor substrate so as to overlap the plurality of second patterns.