KR101232156B1 - liquid crystal display device - Google Patents

Abstract

The present invention relates to an inverter circuit and a liquid crystal display device using the same to reduce the production cost and improve the space efficiency by using a single inverter PCB, in the inverter circuit for driving the lamp, the supply voltage supplied from the voltage source At least one switching unit for converting an AC waveform, a transformer for converting the AC waveform from the switching unit into high-voltage first and second AC waveforms and outputting them to both ends of the lamp, and a first output from the transformer. And a control unit for generating a switching control signal for controlling the switching unit based on the first and second feedback circuits for detecting the tube current of the second AC waveform and the feedback signal from the feedback circuit. .

Inverter, PCB, LCD, Lamp, Controller Board

Description

[0001] The present invention relates to a liquid crystal display device,

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 second inverter substrate for driving the lamps shown in FIG. 1; FIG.

3 is a rear configuration diagram of a liquid crystal display according to the related art.

4 is a view showing a state in which a cover shield is attached in the rear configuration of the liquid crystal display according to the prior art

5 is a schematic block diagram showing an inverter circuit according to the present invention.

6 is a rear configuration diagram of the liquid crystal display device according to the present invention.

7 is a view showing a state in which a cover shield is attached in the rear configuration of the liquid crystal display according to the present invention;

Description of the Related Art [0002]

160: switching unit 170: transformer

181: first feedback circuit 182: second feedback circuit

190: control unit 200: lower structure

300: Inverter PCB 400: Timing Controller Board

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having a liquid crystal display module having a simple appearance by reducing the number of parts and the size and reducing the production cost.

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 tendency, LCD is 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 is required. There are two types of LCD backlights, a direct type method and a light guide plate method. The direct type places several lamps in the 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. In the light guide plate method, a lamp is installed outside the flat plate, and light is incident from the lamp onto the entire surface of the liquid crystal panel using a transparent light guide plate.

FIG. 1 is a cross-sectional view schematically illustrating a lamp driving apparatus of a general liquid crystal display, and FIG. 2 is a diagram illustrating first and second inverter substrates for driving lamps shown in FIG. 1.

As shown in FIGS. 1 and 2, a driving apparatus of a general liquid crystal display device includes a liquid crystal panel 6 and a direct type bag including a plurality of lamps 12 for irradiating light to the liquid crystal panel 6. The first inverter substrate 30 for supplying a light unit, a high voltage AC waveform having a first phase to the first electrodes of the plurality of lamps 12, and a second electrode of the plurality of lamps 12. A second inverter substrate 40 for supplying an AC waveform having a high voltage having a second phase different from the first phase is provided.

Here, the liquid crystal panel 6 is a spacer (not shown) for injecting liquid crystal between the upper substrate 3 and the lower substrate 5 to maintain a constant gap between the upper substrate 3 and the lower substrate 5. It is provided.

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

In addition, 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.

On the other hand, the first inverter substrate 30 includes a first 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 from the first inverter integrated circuit. A plurality of first transformers 34 for converting an AC waveform into a high voltage AC waveform, a plurality of first output terminals 36 connected to each of the plurality of first transformers 34, and a plurality of lamps (12) A plurality of first wires 38 connected to each of the first electrodes and connected to each of the plurality of first output terminals 36 are provided.

In addition, the first inverter integrated circuit switches the switching elements (not shown) in response to a control signal supplied from the system to convert the lamp driving power supplied from the power supply device into an AC waveform to supply the plurality of first transformers 34. Supply. 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 includes a second 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 second inverter integrated circuit. A plurality of second transformers 44 for converting a high voltage into an AC waveform, a plurality of second output terminals 46 connected to each of the plurality of second transformers 44, and a plurality of lamps 12. A second wire 48 connected to each of the second electrodes 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.

Hereinafter, a liquid crystal display according to the related art will be described with reference to the accompanying drawings.

3 is a rear configuration diagram of a liquid crystal display according to the prior art.

As shown in FIG. 3, the liquid crystal display according to the related art includes a plurality of light emitting lamps (not shown) arranged at regular intervals in one direction on the lower structure 60, and both sides of the rear surface of the lower structure 60. A master inverter PCB 70 and a slave inverter PCB 80 having a constant spacing at an edge to apply a high-voltage alternating current waveform to both ends of each of the light emitting lamps, and the master inverter PCB ( 70) and a timing controller board 90 for outputting a drive signal to a liquid crystal display panel (not shown).

In this case, the light emitting lamp is an external electrode light emitting lamp (EEFL) having first and second electrodes formed at both ends of the tube, and the first and second electrodes of the plurality of light emitting lamps are first and second power lines (not shown). Are connected in parallel. The first and second power lines are connected to the master inverter PCB 70 and the slave inverter PCB 80, respectively.

Here, the master inverter PCB 70 and the slave inverter PCB 80 are disposed at both bottom edges of the lower surface of the lower structure 60, respectively, and the timing controller board 90 is disposed on the upper surface of the lower structure 60. It is.

In addition, the light emitting lamp of the backlight unit is driven in a high-high (H-H) manner, and a master inverter PCB 70 having a main controller mounted on one side of the rear structure 60 is provided.

In addition, the master inverter PCB 70 and the slave inverter PCB 80 are provided with input connectors 71 and 81 and output connectors (not shown), respectively.

In addition, a synchronization cable 91 and first cable connectors 72 and 92 for electrically connecting the timing controller board 90 and the master inverter PCB 70 are configured, and the master inverter PCB 70 and The slave inverter PCB 80 is composed of FFC cables 75 and second cable connectors 74 and 84 used to exchange signals between inverters.

In addition, the master inverter PCB 70 and the slave inverter PCB 80 are provided with a plurality of switching elements 76 and 86 and a plurality of transformers 77 and 87, respectively.

The output waveforms 77 and 88 of the master inverter PCB 70 and the slave inverter PCB 80 are reversed to each other.

Meanwhile, since the main controller and the protection circuit (not shown) are further mounted on the master inverter PCB 70, the size is larger than that of the slave inverter PCB 80.

4 is a view showing a state in which the cover shield is attached in the rear configuration of the liquid crystal display according to the prior art.

As shown in FIG. 4, the master inverter PCB 70, the slave inverter PCB 80, and the timing controller board 90 are each covered with a cover shield 100 to protect against external shocks. .

However, the liquid crystal display according to the related art as described above has the following problems.

First, since the master controller PCB has more main controller and protection circuits installed, the size of the master inverter PCB is larger than that of the slave inverter PCB. Therefore, when mounting the PCB, the master inverter PCB and the slave inverter PCB processes must be dualized and processed. When assembling the unit, it is necessary to assemble separately, which makes the working time or assembly process difficult.

Second, since the master inverter PCB and the slave inverter PCB are separated from each other, a medium for transmitting and receiving signals, that is, a cable connector and a cable for connecting the same, is additionally required to reduce production costs.

Third, since the ratio of the master inverter PCB and the slave inverter PCB on the back of the LCM is high, it is spatially limited in arranging the power supply on the set.

Fourth, since the master inverter PCB and the slave inverter PCB are separately disposed, there is a limit in reducing the production cost because the cover shield is formed to protect them.

An object of the present invention is to provide an inverter circuit and a liquid crystal display device using the same to reduce the production cost and space efficiency by using a single inverter PCB to solve the above problems.

Inverter circuit according to the present invention for achieving the above object is an inverter circuit for driving a lamp, at least one switching unit for converting a supply voltage supplied from a voltage source into an AC waveform, and the AC waveform from the switching unit A transformer for converting a high voltage into first and second AC waveforms and outputting the first and second AC waveforms to both ends of the lamp, and first and second feedback circuits for detecting tube currents of the first and second AC waveforms output from the transformer; And a control unit for generating a switching control signal for controlling the switching unit based on the feedback signal from the feedback circuit.

In addition, the liquid crystal display device according to the present invention for achieving the above object is a lower structure for accommodating a liquid crystal panel and a backlight unit including a plurality of lamps that emit light to the liquid crystal panel by generating light by the AC waveform of high pressure And an inverter board formed on the rear surface of the lower structure, at least one switching unit for converting a supply voltage supplied from a voltage source on the inverter board into an AC waveform, and an AC waveform from the switching unit having a high voltage first. A transformer for converting into a second AC waveform and outputting to the both ends of the lamp; first and second feedback circuits for detecting tube currents of the first and second AC waveforms output from the transformer; and from the feedback circuit. An inverter IC for generating a switching control signal for controlling the switching unit based on a feedback signal; Characterized in that it comprises a configured inverter circuit.

Hereinafter, an inverter circuit and a liquid crystal display using the same according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

5 is a schematic block diagram showing an inverter circuit according to the present invention.

As shown in FIG. 5, the inverter circuit 150 for driving the plurality of lamps 110 arranged at regular intervals includes at least one switching unit for converting a supply voltage Vcc supplied from a voltage source into an AC waveform. 160, a transformer 170 for converting the AC waveform from the switching unit 160 into high-pressure first and second AC waveforms 171 and 172 and outputting them to both ends of the lamp 110, and the transformer ( The first and second feedback circuits 181 and 182 for detecting the tube currents of the high voltage first and second AC waveforms output from the 170 and the feedback signals FB1 and 181 from the first and second feedback circuits 181 and 182, respectively. And a controller 190 for generating a switching control signal SCS for controlling the switching unit 160 based on FB2.

Here, the transformer 170 may have a first primary winding 173 connected to the switching unit 160, and the first and second feedback circuits 181 and 182 at regular intervals from the first winding 173. One side is connected to each other) and the other side includes a secondary second winding 174 and a third winding 175 connected to one end and the other end of the lamp 110, respectively.

In addition, the lamp 110 is an external electrode light emitting lamp (EEFL) having first and second electrodes formed at both ends thereof, and the first and second electrodes of the plurality of light emitting lamps are first and second power lines 176 and 177. Are connected in parallel.

6 is a rear configuration diagram of the liquid crystal display device according to the present invention.

As shown in FIG. 6, the liquid crystal display according to the present invention uses a liquid crystal panel (not shown) and a plurality of light emitting lamps (not shown) which emit light to the liquid crystal panel by generating light by an AC waveform having a high voltage. A lower structure 200 for receiving a backlight unit (not shown), an inverter PCB 300 disposed at the bottom of the rear surface of the lower structure 200, and an upper portion of the rear surface of the lower structure 200. It is configured to include a timing controller board 400 spaced apart from the inverter PCB 300 by a predetermined interval.

Here, connectors 310 and 410 are formed at one side of the inverter PCB 300 and the timing controller board 400, respectively, and the connectors 310 and 410 of the inverter PCB 300 and the timing controller board 400 are for synchronization. It is connected via a cable 220.

An input connector 320 is configured at one end of the inverter PCB 300, and an output connector 330 is configured at both ends of the inverter PCB 300.

In addition, on the inverter PCB 300, a plurality of switching units 160 for converting a supply voltage supplied from a voltage source into an AC waveform, and AC waveforms from the switching unit 160, the first and second AC waveforms of high voltage. The transformer 170 is converted to (171, 172) and output to both ends of the lamp 110.

On the other hand, the transformer 170 is provided from the switching unit 160 supplied to the primary first winding 173 by the turns ratio of the primary first winding 173 and the secondary second and third windings 174 and 175. The AC waveform is converted into an AC waveform of high voltage.

In addition, the liquid crystal panel includes a spacer (not shown) for injecting liquid crystal between the upper substrate and the lower substrate and for maintaining a constant gap between the upper substrate and the lower substrate. On the upper substrate of the liquid crystal panel, 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 of the liquid crystal panel, 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, a pad region for connecting data lines and gate lines, respectively, is formed at one side of the lower substrate, and a tape carrier package (not shown) in which a driver integrated circuit for applying a driving signal to the thin film transistor is mounted. Tape 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 of the liquid crystal panel, and the lower polarizing sheet (not shown) is attached to the rear surface of the lower substrate. At this time, the upper and lower polarizing sheets are responsible for extending the viewing angle of the image displayed by the liquid crystal cell matrix.

7 is a view showing a state in which the cover shield is attached in the rear configuration of the liquid crystal display according to the present invention.

As shown in FIG. 7, the inverter PCB 300 and the timing controller board 400 are covered with a cover shield 500 to protect against external shocks and the like.

Therefore, in the related art, an additional cover shield is required to cover the master inverter PCB and the solenoid inverter PCB, but the present invention does not require a separate cover shield by using only one inverter PCB 300.

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

The inverter circuit and the liquid crystal display using the same according to the present invention described above have the following effects.

First, by mounting a conventional master and slave inverter PCB on a single PCB, using a transformer having at least two outputs can reduce the number of switching elements and transformers to reduce the production cost.

Second, by using only one inverter PCB, the PCB size, cover shield and manufacturing space can be reduced.

Third, by arranging one inverter PCB at the bottom of the back of the LCM, the space occupied by the back of the LCM can be reduced to secure a free space.

Fourth, it is possible to simplify the process of mounting and assembling the PCB by mounting a switching element and a transformer each disposed in a conventional inverter PCB divided on one inverter PCB.

Claims (6)

delete delete A liquid crystal panel; A backlight unit including a plurality of lamps generating light by a high voltage alternating current waveform and irradiating the liquid crystal panel; A lower structure accommodating the liquid crystal panel and the backlight unit; An inverter board configured to be configured as a single unit at the bottom of the rear surface of the lower structure; A timing controller board spaced apart from the inverter board above the rear center of the lower structure; A cover shield covering each of the inverter board and the timing controller board; At least one switching unit for converting a supply voltage supplied from a voltage source into an alternating current waveform, a transformer for converting the alternating current waveform from the switching unit into high-pressure first and second alternating current waveforms and outputting them to both ends of the lamp, And an inverter circuit including first and second feedback circuits for detecting tube currents of the first and second alternating current waveforms output from the transformer, and a control unit for controlling the switching unit based on a feedback signal from the feedback circuit. ; And the switching unit and the transformer are formed on the inverter board. 4. The liquid crystal display device according to claim 3, wherein the lamp is an external electrode fluorescent lamp. 4. The liquid crystal display device according to claim 3, wherein the timing controller board and the inverter board are each connected by a cable through a connector configured on one side. 4. The transformer of claim 3, wherein the transformer has a first primary winding connected to the switching unit, and one side of the transformer is connected to the first and second feedback circuits at regular intervals from the first winding, and the other side of the lamp And a secondary second winding and a third winding respectively connected to one side end and the other end of the liquid crystal display device.

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