KR20060055305A - Surface light source, display device having the same, and control method thereof - Google Patents

Abstract

Disclosed are a surface light source device having a partial brightness adjustment function, a display device having the same, and a control method thereof. The discharge tube includes a discharge electrode portion in each of the plurality of lighting regions. The power source supplies power to the discharge electrode portions. The surface light source controller individually adjusts the power level supplied to the discharge electrode of each lighting region to individually adjust the brightness of each lighting region. Accordingly, when the displayed image has a partly dark or light characteristic, the high contrast ratio and low power consumption of the image can be achieved by partially darkening or brightening the brightness of the light source in response to the characteristic of the image.

Description

Surface light source device, display device having same and control method thereof {SURFACE LIGHT SOURCE, DISPLAY DEVICE HAVING THE SAME, AND CONTROL METHOD THEREOF}

1 is a block diagram of a general display device.

2 is a schematic structural diagram of a display device according to a first embodiment of the present invention.

3 is a flowchart illustrating a control process of the surface light source controller shown in FIG. 2.

4 is a schematic diagram illustrating a structure of a discharge electrode unit according to the first embodiment disposed in the lighting region shown in FIG. 2.

FIG. 5 is a schematic diagram illustrating an electrode structure according to a second embodiment disposed in the lighting region shown in FIG. 2.

FIG. 6 is a schematic diagram illustrating an electrode structure according to a third embodiment disposed in the lighting region shown in FIG. 2.

7A and 7B are graphs for explaining the phase change of the frequency of the power supplied to the discharge electrodes shown in FIG. 6.

FIG. 8 is a schematic view illustrating an electrode structure according to a fourth embodiment disposed in the lighting region shown in FIG. 2.

9 is a plan view for explaining a flat discharge tube of the surface light source device according to the first embodiment.

10 is a plan view illustrating a flat discharge tube of the surface light source device according to the second embodiment.

11 is a plan view for explaining a flat discharge tube of the surface light source device according to the third embodiment.

12 is a schematic configuration diagram of a display device having a surface light source device using a light emitting diode.

13 is a schematic structural diagram of a display device according to a second embodiment of the present invention.

FIG. 14 is a circuit diagram illustrating an example of the switching circuit shown in FIG. 13.

15 is a perspective view illustrating a surface light source device according to a first embodiment of the present invention.

FIG. 16 is a vertical cross-sectional view of the surface light source device shown in FIG. 15.

17 is a horizontal cross-sectional view of the surface light source device shown in FIG. 15.

18 is a cross-sectional view illustrating a surface light source device according to a second embodiment of the present invention.

19 is a cross-sectional view illustrating a surface light source device according to a third embodiment of the present invention.

20 is a perspective view illustrating a surface light source device according to a fourth embodiment of the present invention.

21 is a horizontal cross-sectional view of the surface light source device shown in FIG. 20.

22 is a horizontal cross-sectional view illustrating a surface light source device according to a fifth embodiment of the present invention.

23 is a horizontal cross-sectional view illustrating a surface light source device according to a sixth embodiment of the present invention.

24 is a plan view illustrating a surface light source device according to a seventh embodiment of the present invention.

25 is a cross-sectional view illustrating a surface light source device according to an eighth embodiment of the present invention.

26 is a cross-sectional view illustrating a surface light source device according to a ninth embodiment of the present invention.

FIG. 27A is an exploded perspective view schematically illustrating a flat panel display device according to a third exemplary embodiment of the present invention, and FIG. 27B is an enlarged view of region A shown in FIG. 27A.

FIG. 28 is a plan view illustrating an electrode array structure of the backlight unit illustrated in FIG. 27.

FIG. 29 is a block diagram schematically illustrating a driving circuit configuration of the backlight unit illustrated in FIG. 28.

FIG. 30 is a flowchart for describing an operation of a driving circuit of the backlight unit illustrated in FIG. 29.

FIG. 31 is a block diagram illustrating a functional configuration of the backlight controller illustrated in FIG. 29.

32A is a conceptual diagram illustrating a process of separating an image signal included in one frame into horizontal sections, and FIG. 32B is an enlarged view of region B shown in FIG. 32A.

33 is a conceptual view illustrating a process of separating one horizontal scanning line into vertical sections.

FIG. 34 is a conceptual view illustrating a process of separating a plurality of horizontal scan lines constituting one horizontal section into vertical sections.

FIG. 35 is a flowchart for describing a step of detecting a maximum luminance value for each image display area illustrated in FIG. 30 in more detail.

36A to 36C are conceptual views illustrating a process of detecting maximum voltage values for horizontal and vertical sections.

FIG. 37 is a flowchart for explaining in more detail the step of driving the backlight unit of FIG. 30.

38 is a timing diagram of maximum voltage values output from the first and second registers of the backlight controller.

FIG. 39 is a detailed circuit diagram illustrating the horizontal driver and the vertical driver shown in FIG. 29.

40 is a conceptual diagram illustrating waveforms of main nodes of the horizontal driver.

41 is a waveform diagram illustrating a change in duty according to a change in the maximum voltage value in the horizontal section.

FIG. 42 is a timing diagram illustrating an operation of the horizontal driver illustrated in FIG. 29.

FIG. 43 is a timing diagram illustrating an operation of the vertical drive unit illustrated in FIG. 29.

44 is a conceptual diagram illustrating an example in which the luminance of the luminance control region is controlled and driven by the backlight unit according to the luminance distribution of the image displayed on the liquid crystal panel.

The present invention relates to a surface light source device, a display device having the same, and a control method thereof, and more particularly, to a surface light source device having a partial brightness adjustment function, a display device having the same, and a control method thereof.

In general, a liquid crystal display device is a display device for displaying an image by precisely controlling a liquid crystal having a characteristic of changing light transmittance corresponding to an electric field. The liquid crystal display requires light in order to display an image as a non-light emitting device. Accordingly, the liquid crystal display device includes a backlight unit disposed on the rear surface of the liquid crystal panel to obtain the light.

The backlight unit is mainly used a cold cathode fluorescent lamp (CCFL) and a flat-format fluorecent lamp type surface light source device assembled with a substrate on which the phosphor layer is distributed. . In addition, as fluorescent lamps used for backlights, external electrode fluorescent lamps (EEFLs) in which both electrodes are disposed outside the tube, and electrodeless fluorescent lamps that do not form electrodes are used. In the fluorescent lamp, a phosphor is coated on an inner surface of the discharge space, and discharge gas such as xenon, neon, and mercury (Hg) is filled in the discharge space.

1 is a block diagram of a general display device.

Referring to FIG. 1, a display device includes a liquid crystal panel 2 having a liquid crystal layer formed between two substrates, and a backlight device disposed on a rear surface of the liquid crystal panel 2 to supply a backlight to the liquid crystal panel 2. It includes (4).

The contrast of the optical image displayed on the display device is affected by the brightness of the backlight and the illuminance of the surrounding environment. In addition, the scene characteristics of the displayed optical image are also affected. For example, when displaying a dark scene, the number of displayed pixels is reduced, so that the resolution is displayed at a low level.

In order to solve the problem of the display device having such characteristics, techniques for flexibly adjusting the brightness of the backlight according to the illumination of the surrounding environment or the characteristics of the displayed image have been proposed. U. S. Patent No. 5,717, 422 discloses a high contrast passive display in which the brightness of a light source is adjusted according to the illumination of the surrounding environment and the characteristics of the displayed image.

However, since the brightness of the light source is adjusted for the entire light source, it is difficult to realize high contrast when the screen is only partially dark or bright.

In addition, while the dark scene is displayed by the control of the light source, the power consumption by the light source is partially lowered, but when the partially bright scene is displayed, the brightness of the light source is increased as a whole so that the power consumption is still high. .

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a surface light source device which can partially adjust the brightness according to the characteristics of the image.

It is another object of the present invention to provide a display device including the surface light source device as described above, by which brightness of a light source is partially adjusted differently according to characteristics of an image, thereby achieving high contrast and high efficiency.

Another object of the present invention is to provide a control method of the flat panel display.

A surface light source device according to one feature for realizing the object of the present invention includes a discharge tube, a power supply source and a surface light source control unit. The discharge tube includes a discharge electrode part in each of the plurality of lighting regions. The power source provides power to the discharge electrode portions. The surface light source controller individually adjusts the power level supplied to the discharge electrode of each lighting region to individually adjust the brightness of each lighting region.

According to another aspect of the present invention, there is provided a surface light source device including a discharge tube, a power supply source, a brightness controller, and a surface light source controller. The electromotive force generating unit supplies an induced electromotive force for inducing plasma discharge to the discharge tube. The power supply source provides power to the electromotive force generating unit. The brightness adjusting unit is uniformly distributed in the discharge tube to form a plurality of unit brightness adjusting regions in the discharge tube, and partially adjusts the brightness of the corresponding region. The surface light source controller controls the brightness controller to individually adjust the brightness of the unit brightness control area.

According to another aspect of the present invention, there is provided a display apparatus including a display panel and a surface light source unit disposed on a rear surface of the display panel. The surface light source unit provides light to the display panel in which brightness is partially adjusted in consideration of characteristics of an image signal supplied to the display panel.

According to an aspect of the present invention, there is provided a method of controlling a display device, the method including a display panel and a surface light source unit for providing light to the display panel. Detecting a luminance signal and a synchronization signal from an image signal supplied from a circle; detecting a maximum luminance value for each image display region provided in the display panel; and a maximum luminance for each luminance control region provided in the surface light source unit. And dividingly driving the surface light source unit based on the value.

According to such a surface light source device, a display device having the same, and a control method thereof, when the displayed image has a partly dark or bright characteristic, the brightness of the light source is partially darkened or brightened by adapting to the characteristic of the image, High contrast and low power consumption can be achieved.

Hereinafter, with reference to the accompanying drawings, it will be described in detail the present invention.

Example 1 of a Display Device

2 is a schematic structural diagram of a display device according to a first embodiment of the present invention.

Referring to FIG. 2, the display device 100 according to the first exemplary embodiment of the present invention includes a flat discharge tube 110, a display panel unit 120, an image signal source 130, a power supply 140, and a surface light source. The controller 150 is included.

The flat discharge tube 110 includes discharge electrodes 114 formed in each of the plurality of lighting regions 112. The lighting regions 112 are divided by the spacer 116 to have a rectangular, circular or polygonal structure.

The display panel unit 120 includes a plurality of pixel groups 122 disposed on the flat discharge tube 110 and grouped into n * m pixels. The size of the pixel group 122 is preferably the same as the size of the lighting region of the flat discharge tube 110 disposed on the rear surface.

The display panel unit 120 includes a liquid crystal panel including an array substrate on which a plurality of TFTs are arranged, an opposing substrate facing the array substrate, and a liquid crystal layer formed between the array substrate and the opposing substrate. . The display panel unit 120 corresponds to an image signal to a gate driver (not shown) for activating a gate line connected to a gate electrode of the thin film transistor (TFT) and a source line connected to a source electrode of the thin film transistor (TFT). And a source driver (not shown) for supplying a voltage.

The video signal source 130 is a graphic controller provided in an external device such as a host. The image signal source 130 supplies an image signal to be displayed to the display panel unit 120 and the surface light source controller 150.

The power supply source 140 supplies power for driving the plurality of discharge electrodes to the surface light source controller 150.

The surface light source controller 150 includes an optical sensor 152, a backlight controller 154, and a power level controller 156, and the characteristics of the image signal supplied from the image signal source 130 and illuminance of the surrounding environment. As a result, the power level supplied to the discharge electrodes 114 formed in the respective lighting regions 112 is individually adjusted to adjust the brightness of each lighting region 112 individually.

In detail, the optical sensor 152 detects illuminance of the surrounding environment and supplies the detected brightness signal to the backlight controller 154.

The backlight controller 154 checks the characteristics of the brightness signal provided from the optical sensor 152 and the image signal provided from the image signal source 130, and accordingly, the backlight controller 154 adjusts the brightness of each lighting area. The power level adjusting signal for adjusting is provided to the power level adjusting unit 156.

The power level adjusting unit 156 receives the power supplied from the power supply source 140 and discharge electrode 114 of the lighting region 112 according to the characteristics of the image signal input from the image signal source 130. To adjust the power level.

3 is a flowchart illustrating a control process of the surface light source controller shown in FIG. 2.

2 and 3, the surface light source controller 150 receives an image signal supplied from the image signal source 130 (step S110). The video signal includes a video signal including a luminance signal and a horizontal / vertical synchronization signal (Hsync / Vsync).

Subsequently, the surface light source controller 150 calculates an average value of image brightness corresponding to each of the lighting regions 112 of the flat discharge tube 110 (step S120).

Subsequently, the surface light source controller 150 controls the power level supplied corresponding to each of the lighting regions based on the average value of the image brightness (step S130).

Example-1 of the discharge electrode part

4 is a schematic diagram illustrating a structure of a discharge electrode part according to the first embodiment disposed in the lighting region shown in FIG. 2.

2 and 4, the discharge electrode part 114A according to the first embodiment may include a first discharge electrode 114a and a first flat discharge electrode 114b connected to the power level controller 156. A second discharge electrode 114b disposed opposite to each other. The second discharge electrode 114b is connected to the ground terminal. The first and second discharge electrodes 114a and 114b have a flat plate shape, and are supplied with a level-controlled power from the power level adjusting unit 156 in accordance with characteristics of an image signal.

<Example-2 of the discharge electrode portion>

FIG. 5 is a schematic diagram illustrating an electrode structure according to a second embodiment disposed in the lighting region shown in FIG. 2.

2 and 5, the discharge electrode unit 114B according to the second embodiment includes a third discharge electrode 114c and the third flat discharge electrode 114c connected to the power level control unit 156. And a fourth discharge electrode 114d disposed to face each other. The fourth discharge electrode 114d is connected to the ground terminal. The third and fourth discharge electrodes 114c and 114d have a flat spiral shape, and are supplied with a level-controlled power from the power level adjusting unit 156 in accordance with characteristics of an image signal.

Example-3 of the discharge electrode part

FIG. 6 is a schematic diagram illustrating an electrode structure according to a third embodiment disposed in the lighting region shown in FIG. 2.

2 and 6, discharge electrodes 114C according to the third embodiment are disposed to face each other on a diagonal line and are fifth and sixth electrically connected to the power level controller 156 or the ground terminal. , Seventh and eighth discharge electrodes 114e, 114f, 114g, 114h. The fifth and sixth discharge electrodes 114e and 114f are electrically connected to the power level controller 156, and the seventh and eighth discharge electrodes 114g and 114h are electrically connected to the ground terminal. . The fifth to eighth discharge electrodes 114e, 114f, 114g, and 114h have a flat plate shape, and receive power adjusted to the characteristics of the image signal from the power level adjusting unit 156. Frequency of power input to each of the fifth and sixth discharge electrodes 114e and 114f has a different phase.

7A and 7B are graphs for explaining the phase change of the frequency of the power supplied to the discharge electrodes shown in FIG. 6.

6 and 7A, for example, a first frequency of power supplied to the fifth discharge electrode 114e and a second frequency of power supplied to the sixth discharge electrode 114f have a phase difference of 180 degrees. . In FIG. 7A, + Vpp is the maximum value of the power supply, and -Vpp is the minimum value of the power supply.

6 and 7B, as another example, the first frequency of the power supplied to the fifth discharge electrode 114e and the second frequency of the power supplied to the sixth discharge electrode 114f have a phase difference of 90 degrees. .

Example-4 of the discharge electrode part

FIG. 8 is a schematic view illustrating an electrode structure according to a fourth embodiment disposed in the lighting region shown in FIG. 2.

2 and 8, discharge electrodes 114D according to the fourth embodiment are disposed to face each other on a diagonal line, and are ninth and tenth electrically connected to the power level controller 156 or a ground terminal. And eleventh and twelfth discharge electrodes 114i, 114j, 114k, and 114l. The ninth and tenth discharge electrodes 114i and 114j are electrically connected to the power level controller 156, and the eleventh and twelfth discharge electrodes 114k and 114l are electrically connected to the ground terminal. . The ninth through twelfth discharge electrodes 114i, 114j, 114k, and 114l have a flat spiral shape and are supplied with a level-controlled power from the power level adjusting unit 156 according to characteristics of an image signal. The frequencies of power input to the ninth and tenth discharge electrodes 114i and 114j respectively have different phases.

Example-1 of flat discharge tube

9 is a plan view for explaining a flat discharge tube of the surface light source device according to the first embodiment.

Referring to FIG. 9, the planar discharge tube 110 of the surface light source device according to the first embodiment includes a plurality of square-shaped lighting regions 112. The lighting regions 112 are partitioned by the spacer 116. The lighting area includes a pair of flat discharge electrodes shown in FIG. 4, or a pair of flat spiral discharge electrodes shown in FIG. 5. Of course, two pairs of flat discharge electrodes or two pairs of flat spiral discharge electrodes shown in FIGS. 6 and 8 may be provided.

Example-2 of flat discharge tube

10 is a plan view illustrating a flat discharge tube of the surface light source device according to the second embodiment.

Referring to FIG. 10, the planar discharge tube 110a of the surface light source device according to the second embodiment includes a plurality of circular lighting regions 112a. The lighting regions 112a are partitioned by the spacer 116a.

Example-3 of a flat discharge tube

11 is a plan view for explaining a flat discharge tube of the surface light source device according to the third embodiment.

Referring to FIG. 11, the planar discharge tube 110b of the surface light source device according to the third embodiment includes a plurality of hexagonal lighting regions 112b. The lighting regions 112b are partitioned by the spacer 116b.

The above-described lighting areas may be provided with various light sources, in particular, a point source of light. In the present embodiment, a light emitting diode (LED) is provided as an example of a light source.

12 is a schematic configuration diagram of a display device having a surface light source device using a light emitting diode.

Referring to FIG. 12, the display device 100 includes a flat discharge tube 160, a display panel unit 120, an image signal source 130, a power supply 140, and a surface light source controller 150. Compared with FIG. 2 described above, the same reference numerals are assigned to the same components, and description thereof will be omitted.

The flat discharge tube 160 includes light emitting diodes 164 formed in the plurality of lighting regions 162. The lighting region 162 is partitioned by the spacer 166 to have a rectangular, circular or polygonal structure. An anode end and a cathode end of the light emitting diode 164 are individually connected to the power level controller 156 to receive power at different levels.

Example 2 of the Display Device

13 is a schematic structural diagram of a display device according to a second embodiment of the present invention.

Referring to FIG. 13, the display device 200 according to the second exemplary embodiment includes a flat discharge tube 210, first and second electromotive force generating units 218 and 219, a display panel unit 220, and an image signal source ( 230, a power supply 240, and a surface light source controller 250.

The flat discharge tube 210 includes discharge electrodes 214 formed in the plurality of lighting regions 212. The lighting regions 212 are partitioned by the spacer 216 to have a rectangular, circular or polygonal structure.

The first electromotive force generator 218 is disposed at one side of the flat discharge tube 210 to supply an induced electromotive force for inducing plasma discharge to the flat discharge tube 210. The second electromotive force generating unit 219 is disposed on the other side of the flat discharge tube 210 to supply the induced electromotive force for inducing plasma discharge to the flat discharge tube 210. The first and second electromotive force generators 218 and 219 may include a flat discharge electrode disposed at both ends of the flat discharge tube 210 and a ferrite core disposed at both ends of the flat discharge tube 210, respectively. core) and a coil wound around the ferrite core, one end of which is connected to the plate discharge electrode and the other end of which is connected to the power supply source.

The display panel 220 includes a plurality of pixel groups 222 disposed on the flat discharge tube 210 and grouped into n * m pixels. The size of the pixel group is preferably the same as the size of the lighting area provided in the flat discharge tube 210 disposed on the rear surface of the display panel unit 220.

The video signal source 230 is a graphic controller provided in an external device such as a host. The image signal source 230 supplies an image signal to the display panel unit 220 and the surface light source controller 250.

The power supply source 240 supplies power to the surface light source controller 250 to drive the discharge electrodes 214 formed in the flat discharge tube 210.

The surface light source controller 250 includes an optical sensor 252, a backlight controller 254, a power level controller 256, and a switching circuit unit 258. The surface light source controller 150 includes an optical sensor 152. And a discharge electrode formed in each of the lighting regions 212 according to characteristics of the image signal supplied from the image signal source 230 and illumination of the surrounding environment, including a backlight controller 154 and a power level controller 156. The brightness of each lighting area 212 is individually adjusted by individually adjusting the power level supplied to 214.

In detail, the photosensor 252 detects illuminance of the surrounding environment and supplies the detected brightness signal to the backlight controller 254.

The backlight controller 254 checks the characteristics of the brightness signal provided from the optical sensor 252 and the image signal provided from the image signal source 230, and adjusts the brightness of each lighting area according to the result. The power level control signal is provided to the power level control unit 256, and a lighting control signal for controlling the lighting and turning off of each lighting area is provided to the switching circuit unit 258.

The power level adjusting unit 256 receives power supplied from the power supply source 240 and discharge electrodes 214 of the lighting region 212 according to characteristics of the image signal input from the image signal source 230. To adjust the power level.

As the lighting control signal is supplied from the backlight control unit 254, the switching circuit unit 258 turns on or off the corresponding lighting area provided in the flat discharge tube 210.

FIG. 14 is a circuit diagram illustrating an example of the switching circuit shown in FIG. 13.

13 and 14, a plurality of bipolar transistors 258a formed to correspond to each of the discharge electrodes 214 provided in the planar discharge tube 210 are included. One bipolar transistor is electrically connected to the discharge electrode formed in one discharge region. The emitter terminal of the bipolar transistor is connected to the ground terminal, the base terminal is connected to the backlight controller 254, and the collector terminal is connected to the discharge electrode.

In operation, the bipolar transistor 258a is turned on / off in response to a lighting control signal supplied from the backlight controller 254 to connect the discharge electrode and the ground terminal on / off.

In FIG. 14, the base end of each of the bipolar transistors is electrically connected to the backlight control unit 254 through one line, and the collector end is electrically connected to the discharge electrode through one line to control power supply as a whole. Is shown. However, it will be apparent to those skilled in the art that lines may be provided to correspond to the number of bipolar transistors so that the discharge electrodes may be individually powered.

Example-1 of surface light source device

15 is a perspective view illustrating a surface light source device according to a first embodiment of the present invention. FIG. 16 is a vertical cross-sectional view of the surface light source device shown in FIG. 15. 17 is a horizontal cross-sectional view of the surface light source device shown in FIG. 15.

15 to 17, the surface light source device 350 according to the first embodiment of the present invention surrounds the flat discharge tube 351 and one edge region and the other edge region of the flat discharge tube 351, respectively. It includes the first and second electromotive force generating unit 360, 370, and receives the power adjusted according to the characteristics of the image signal to emit light.

The flat discharge tube 351 includes two substrates facing each other, and an upper electrode 352 and a lower electrode 354 formed on each of the substrates and partitioning a plurality of lighting regions on a plane. The second electromotive force generators 360 and 370 perform light emission in response to power supplied to the respective lighting regions individually. In FIG. 16, the upper electrode 352 is formed on the entire surface of the upper substrate, and the lower electrode 354 is formed on the lighting region partitioned on the lower substrate. In FIG. 16, a plurality of diffusion members 355 and a reflection member 356 covering the diffusion member 355 are further formed on the rear surface of the lower substrate. The diffusion member 355 is for converting the emitted light more uniformly, and the reflection member 356 is for reflecting light leaking in the -z-axis direction in the + z-axis direction to increase light efficiency. .

The lighting regions are partitioned by the spacer 353 to maintain a constant distance between the two substrates. The lighting regions defined by the spacer 353 may have various shapes such as a square, a circle, or a polygon when viewed in a plane.

The first electromotive force generating unit 360 has a first planar discharge electrode 361 disposed at one end of the plurality of discharge regions of the planar discharge tube 351, and has an U-shape to form an edge of the planar discharge tube. Clipping first ferrite core 363, the first coil 364 wound on the first ferrite core 363, one end is connected to the first plate discharge electrode 361 and the other end is connected to a power supply source do.

The second electromotive force generating unit 370 has a U-shaped shape with a second flat discharge electrode 371 disposed at the other end of the flat discharge tube 351 while facing the first electromotive force generating unit 360. A second ferrite core 373 that clips the edges of the flat discharge tube, the second ferrite core 373 is wound, one end of which is connected to the second plate discharge electrode 371 and the other end of which is connected to a power supply source Two coils 374.

According to the surface light source device according to the first embodiment of the present invention described above, the upper electrode is formed on the entire surface of the upper substrate, a region partitioned by spacers defines a plurality of lighting regions, and the lower electrode is the lighting region described above. By forming corresponding to each of them, the partial brightness function can be given to the surface light source device.

Example-2 of surface light source device

18 is a cross-sectional view illustrating a surface light source device according to a second embodiment of the present invention.

Referring to FIG. 18, the surface light source device 450 according to the second embodiment of the present invention may include a flat discharge tube 351, first and second electromotive force generating units 360 and 370, and a plurality of small single winding cores ( 457), and emits light by receiving power adjusted according to characteristics of an image signal. Compared with FIGS. 14-16, the same component number is attached | subjected and the detailed description is abbreviate | omitted.

A plurality of small single winding cores 457 are disposed on the rear surface of the flat discharge tube 351.

Example-3 of the surface light source device

19 is a cross-sectional view illustrating a surface light source device according to a third embodiment of the present invention.

Referring to FIG. 19, the surface light source device 550 according to the third embodiment of the present invention may include a flat discharge tube 351, first and second electromotive force generating units 360 and 370, and a plurality of permanent magnets 558. And light supplied with power adjusted according to characteristics of an image signal. Compared with FIGS. 14-16, the same component number is attached | subjected and the detailed description is abbreviate | omitted.

The plurality of permanent magnets 558 are disposed on the rear surface of the flat discharge tube 351.

Example-4 of surface light source device

20 is a perspective view illustrating a surface light source device according to a fourth embodiment of the present invention. 21 is a horizontal cross-sectional view of the surface light source device shown in FIG. 20.

20 and 21, the surface light source device 650 according to the fourth embodiment of the present invention includes a flat discharge tube 651 and a first electromotive force generating unit surrounding one edge region of the flat discharge tube 651. 660 and a second electromotive force generator 670 surrounding the other edge region of the flat discharge tube 651, and emits light by receiving power adjusted according to characteristics of an image signal.

The flat discharge tube 651 may include an upper substrate, a lower substrate facing the upper substrate, an upper electrode 659 formed on the upper substrate to define a lighting region, and a lower portion formed on the lower substrate corresponding to the lighting regions. An electrode 654.

The flat discharge tube 651 may be turned on or off from the switching circuit unit 258, and may be supplied to a power source individually supplied to each of the lighting regions of the first and second electromotive force generating units 660 and 670. In response, the light emitting operation is performed. The upper electrode 659 has a band shape patterned in the horizontal direction and defines a lighting area. One side of the upper electrode 659 is electrically connected to the first electromotive force generator 660, and the other side is electrically connected to the second electromotive force generator 670.

The first electromotive force generator 660 includes a plurality of first sub electromotive force generators, which is disposed at one side of the flat discharge tube 651, and supplies power supplied from the power level controller to the upper electrode 659. Supply to one side of.

The first sub-electromotive force generating units are disposed at predetermined intervals on one side of the flat discharge tube 651. Each of the first sub electromotive force generating units may be wound around a first flat discharge electrode, a first ferrite core and a first ferrite core that clip an edge of the planar discharge tube 651 having a U-shape, and one end of which is wound. And a first coil connected to the first planar discharge electrode and the other end connected to a power supply source.

The second electromotive force generating unit 670 is composed of a plurality of second sub electromotive force generating units, disposed on the other side of the flat discharge tube 651 to supply power supplied from the power level adjusting unit of the upper electrode 659. Supply to the other side.

The second sub-electromotive force generating units are disposed to be spaced apart from each other by a predetermined interval in the other short side region of the flat discharge tube 651. Each of the second sub electromotive force generating units may be wound around a second flat discharge electrode and a second ferrite core and a second ferrite core that clip an edge of the planar discharge tube 651 to have a U-shape. And a second coil connected to the second flat discharge electrode and the other end connected to a power supply source.

According to the surface light source device according to the fourth embodiment of the present invention described above, the upper electrode is formed to have a band shape to define a lighting area, and a plurality of lower electrodes are formed corresponding to the lighting area, thereby providing the surface light source device. Partial brightness can be given.

Example-5 of the surface light source device

22 is a horizontal cross-sectional view illustrating a surface light source device according to a fifth embodiment of the present invention.

Referring to FIG. 22, the surface light source device 750 according to the fifth exemplary embodiment of the present invention may include a flat discharge tube 751 and a first antenna electrode 760 formed in one edge region of the flat discharge tube 751. And a second antenna electrode portion 770 formed at the other edge region of the flat discharge tube 751 and emitting light by receiving power adjusted according to characteristics of an image signal.

The flat discharge tube 751 includes an upper substrate, a lower substrate facing the upper substrate, an upper electrode 759 formed on the upper substrate to define a lighting region, and a lower portion formed on the lower substrate corresponding to the lighting regions. Electrode 754.

The flat discharge tube 751 responds to a lighting or turning-off signal supplied from the switching circuit unit 258 and a power supplied separately to each of the lighting regions of the first and second antenna electrodes 760 and 770. Perform a light emission operation. The upper electrode 759 has a band shape patterned in the horizontal direction and defines a lighting area. One side of the upper electrode 759 is electrically connected to the first antenna electrode 760, and the other side is electrically connected to the second antenna electrode 770.

The first antenna electrode part 760 is composed of a plurality of first antenna electrodes, is disposed on one side of the flat discharge tube 751, and the power supplied from the power level controller is supplied to the upper electrode 759. Supply to one side. The first antenna electrodes have a coil shape and are spaced apart from each other at a predetermined short side region of the flat discharge tube 651.

The second antenna electrode part 770 is composed of a plurality of second antenna electrodes, disposed on the other side of the flat discharge tube 751, and supplies power supplied from the power level controller to the upper electrode 759. Supply to the other side. The second antenna electrodes have a coil shape and are spaced apart from each other by a predetermined interval in one short side region of the flat discharge tube 651.

Example 6 of surface light source device

23 is a horizontal cross-sectional view illustrating a surface light source device according to a sixth embodiment of the present invention. In particular, an example in which a plurality of antenna electrodes are arranged in a unit discharge region is shown.

Referring to FIG. 23, the surface light source device 850 according to the sixth embodiment of the present invention may include a flat discharge tube 851 and first, second, third and fourth regions of the flat discharge tube 851, respectively. And first, second, third, and fourth antenna electrode parts 860, 862, 864, and 866 formed in the light emitting device.

The flat discharge tube 851 may include an upper substrate, a lower substrate facing the upper substrate, an upper electrode 859 formed on the upper substrate to define a lighting region, and a lower electrode formed on the lower substrate corresponding to the lighting region. 854.

The flat discharge tube 851 may be individually supplied to each of the lighting regions of the switching circuit unit 258 and the lighting regions of the first to fourth antenna electrode parts 860, 862, 864, and 866. The light emitting operation is performed in response to the power supply. The upper electrode 859 has a band shape patterned in the horizontal direction and defines a lighting area.

The first region of the upper electrode 859 is electrically connected to the first antenna electrode portion 860, the second region is electrically connected to the second antenna electrode portion 862, and the third region is the The fourth antenna electrode 864 is electrically connected to the third antenna electrode 864, and the fourth region is electrically connected to the fourth antenna electrode 866.

The first antenna electrode part 860 is composed of a plurality of first antenna electrodes, is disposed in a first region of the flat discharge tube 851, and supplies power supplied from the power level controller to the upper electrode 859. Is supplied to the first region. The first antenna electrodes have a coil shape and are spaced apart from each other by a predetermined interval.

The second antenna electrode part 862 includes a plurality of second antenna electrodes, is disposed in a second area of the flat discharge tube 851, and supplies power supplied from the power level controller to the upper electrode 859. Supply to the second region. The second antenna electrodes have a coil shape and are spaced apart from each other by a predetermined interval.

The third antenna electrode part 864 is configured of a plurality of third antenna electrodes, is disposed in a third region of the flat discharge tube 851, and supplies power supplied from the power level controller to the upper electrode 859. Is supplied to the third region. The third antenna electrodes have a coil shape and are spaced apart from each other by a predetermined interval.

The fourth antenna electrode part 866 is composed of a plurality of fourth antenna electrodes, is disposed in the fourth region of the planar discharge tube 851, and supplies the power supplied from the power level controller to the upper electrode 859. Supply to the fourth region. The fourth antenna electrodes have a coil shape and are spaced apart from each other by a predetermined interval.

Example 7 of the surface light source device

24 is a plan view illustrating a surface light source device according to a seventh embodiment of the present invention. In particular, an example is shown in which a plurality of cylindrical discharge tubes are arranged in parallel to form a surface light source.

Referring to FIG. 24, the surface light source device 950 according to the seventh exemplary embodiment includes a plurality of cylindrical discharge tubes 951 and brightness controllers 952 formed in each of a plurality of regions of the cylindrical discharge tube 951. Then, the power is adjusted according to the characteristics of the video signal and emits light.

The cylindrical discharge tubes 951 are arranged in parallel on the same plane. Both sides of the cylindrical discharge tube 951 are connected to a power level control unit, and emits light by receiving power adjusted according to characteristics of an image signal.

The brightness adjusting units 952 include a transparent electrode surrounding the outer shell of the cylindrical discharge tube 951. The transparent electrodes are arranged to have a uniform interval.

The cylindrical discharge tube 951 may be an external electrode fluorescent lamp (EEFL) having an external electrode as shown in FIG. 25 below, or a cold cathode fluorescent lamp having an internal electrode as shown in FIG. 26 below. Fluorescent Lamp (CCFL).

Example 8 of surface light source device

25 is a cross-sectional view illustrating a surface light source device according to an eighth embodiment of the present invention.

Referring to FIG. 25, the surface light source device according to the eighth embodiment includes a cylindrical discharge tube 961, an external electrode 962 surrounding both ends of the cylindrical discharge tube 961, and a transparent electrode 964 surrounding a part of the outer skin. ). Ferrite cores 966 are disposed at both ends of the cylindrical discharge tube 961. The ferrite core 966 has a coil 968 wound in a predetermined number, one end of the coil 968 is electrically connected to the external electrode 962, the other end is a power supply, that is, the power level control unit Connected.

Example 9 of Surface Light Source Apparatus

26 is a cross-sectional view illustrating a surface light source device according to a ninth embodiment of the present invention.

Referring to FIG. 26, the surface light source device according to the ninth embodiment includes a cylindrical discharge tube 971, an inner electrode 972 formed in the cylindrical discharge tube 971, and a transparent electrode 974 surrounding a portion of an outer skin. do. Ferrite cores 976 are disposed at both ends of the cylindrical discharge tube 971. The ferrite core 976 has a predetermined number of coils coils (978), one end of the coil (978) is electrically connected to the internal electrode 972, the lead exposed in the cylindrical discharge tube (971) The other end is connected to a power supply, that is, a power level control unit.

As described above, by using the surface light source device according to the present invention, the brightness of the light source is partially differently brightened or darkened, so that the image displayed on the display device is partially dark or bright according to the characteristics of the image displayed. The brightness of the light source can be partially different from each other to obtain high contrast ratio and to reduce power consumption with high efficiency.

Example-3 of the Display Device

FIG. 27A is an exploded perspective view schematically illustrating a flat panel display device according to a third exemplary embodiment of the present invention, and FIG. 27B is an enlarged view of region A shown in FIG. 27A. In particular, the concept of surface division luminance control will be described.

27A and 27B, the flat panel display device 400 according to the third exemplary embodiment of the present invention includes a liquid crystal panel 410 and a backlight unit 420 disposed on the rear surface of the liquid crystal panel 410. . A diffusion plate or a prism sheet may be included between the liquid crystal panel 410 and the backlight unit 420 to improve the characteristics of the light provided from the backlight unit 420.

The backlight unit 420 has a plurality of luminance control areas BCS that are face-divided in a matrix form of M rows (columns) and N columns (lines). The luminance control regions BCS are individually controlled in response to luminance characteristics of each image displayed in the plurality of image display regions VDS of the liquid crystal panel 410.

The image display areas VDS correspond one-to-one to the luminance control area BCS of the backlight unit 420. The size of the image display area VDS is determined according to the surface area of the luminance control area BCS. That is, the size occupied by the light irradiated to the liquid crystal panel 410 in one luminance control area BCS is a * b (a: number of horizontal pixels, b: number of vertical pixels, and a, b are amounts greater than 1). (Integer), the size of one image display area VDS is determined as 'a * b'.

As such, the liquid crystal panel 410 is virtually face-divided corresponding to the luminance control area BCS of the backlight unit 420.

FIG. 28 is a plan view illustrating an electrode array structure of the backlight unit illustrated in FIG. 27.

Referring to FIG. 28, the backlight unit 420 may include a flat fluorescent lamp having a plurality of discharge electrode pairs arranged in a matrix form. The plate fluorescent lamp includes at least one pair of first and second discharge electrodes 421 and 422 in each unit luminance control area BCS.

The first discharge electrodes 421 are electrically connected in common along each column, and the second discharge electrodes 422 are electrically connected in common along each column so that the entirety of the matrix is electrically connected. Define the connection structure.

Hereinafter, each column (horizontal section) of the liquid crystal panel 410 and the backlight unit 420, i.e., the image display area VDS and the brightness control area BCS, is represented by Yn, and each row (Vertical section) is indicated by Xm. Where n, m and N are natural numbers, 1 ≦ n ≦ N, and 1 ≦ m ≦ M.

In the present embodiment, the backlight unit 20 is described as an example of a single flat fluorescent lamp, but it is apparent to those skilled in the art that the backlight unit 20 may be applied to a backlight unit in which a plurality of LEDs are arranged.

FIG. 29 is a block diagram schematically illustrating a driving circuit configuration of the backlight unit illustrated in FIG. 28.

Referring to FIG. 29, the driving circuit of the backlight unit 420 includes a backlight controller 430, an inverter 440, a horizontal driver 450, and a vertical driver 460.

The backlight controller 430 receives an image signal from an external image signal source (not shown). The video signal source is a signal source for supplying a computer video signal output from a video controller of a computer system or a television video signal output from a television broadcast receiver. Supply. The video signal supplied from the video signal source is also input to a liquid crystal display driving circuit (not shown) to perform driving control of the conventional liquid crystal panel 410.

The backlight controller 430 detects a luminance signal and a horizontal / vertical synchronization signal from the input image signal, and compares the luminance values of all pixels of each region for each image display region VDS to obtain a maximum luminance value. Is detected.

The backlight controller 430 drives the horizontal driver 450 and the vertical driver 460 based on the detected maximum luminance value to synchronize the backlight unit with the image corresponding to the image display area VDS. The luminance of each luminance control area BCS is controlled by driving the 420 separately.

The inverter 440 converts the DC voltage Vdc input from the outside into an AC voltage having a predetermined frequency and amplitude to discharge the backlight unit 420 through the horizontal driver 450 and the vertical driver 460. Supply to the electrodes. Detailed configurations and detailed operations of the driving circuit of the backlight unit 420 will be described later.

Each of the horizontal driver 450 and the vertical driver 460 controls the amount of power supplied to the discharge electrodes of the backlight unit 420 in response to the control of the backlight controller 430. Adjust through

The horizontal driver 450 supplies N AC voltages Y1 Vin, Y2 Vin, ..., YN-1 Vin, YN Vin corresponding to the first line Y1 to the Nth line YN, The vertical driver 460 supplies M AC voltages X1 Vin, X2 Vin, ..., XM-1 Vin, and XM Vin corresponding to the first column X1 through the Mth column XM.

FIG. 30 is a flowchart for describing an operation of a driving circuit of the backlight unit illustrated in FIG. 29.

29 and 30, the backlight controller 430 first receives an image signal from the outside (step S210). The video signal includes a video signal including a luminance signal and a horizontal / vertical synchronization signal (Hsync / Vsync).

Subsequently, a luminance signal and a synchronization signal are detected from the image signal (step S220), and a maximum luminance value is detected for each image display area VDS (step S230).

Subsequently, the backlight unit is dividedly driven based on the maximum luminance value of each luminance control area BCS (step S240).

FIG. 31 is a block diagram illustrating a functional configuration of the backlight controller illustrated in FIG. 29.

29 and 31, the backlight controller 430 may include a luminance signal detector 431, a synchronization signal detector 432, a timing controller 433, a maximum voltage detector 434, a first register 436, and a first register. Two registers 437. In FIG. 31, for convenience of explanation, the logical separation is not performed by hardware. For example, the backlight controller 430 may be configured as a micom or a digital signal processor (DSP).

The luminance signal detector 431 detects a luminance signal from an externally provided image signal and provides the detected luminance signal to the maximum voltage detector 434. The luminance signal detector 431 may be configured as a low pass filter (LPF). The low pass filter removes a high frequency signal in which a color signal component exists and passes only a low frequency signal in which a luminance signal component exists as an image signal is input.

The synchronization signal detector 432 detects horizontal and vertical synchronization signals from the video signal, and provides the detected horizontal and vertical synchronization signals to the timing controller 433.

The timing controller 433 generates the first, second and third timing control signals required for each part of the backlight controller 430 based on the horizontal and vertical synchronization signals.

The maximum voltage detector 434 receives a luminance signal from the luminance signal detector 431 as the first timing control signal is supplied from the timing controller 433, and thus the maximum voltage for each horizontal section Y1 to YN. Is detected, and the maximum voltage for the vertical sections X1 to XM corresponding to each of the horizontal sections Y1 to YN is detected. Each detected maximum voltage value is sequentially stored in the first and second registers 436 and 437.

As the second timing control signal is supplied from the timing controller 433, the first register 436 stores maximum voltage values of N horizontal sections Y1 to YN.

As the third timing control signal is supplied from the timing controller 433, the second register 437 may set a maximum voltage value for the M vertical sections X1 to XM for each of the N horizontal sections Y1 to YN. Save it. The second register 437 includes N sub registers 437_1, 437_2,..., 437_N-1, 437_N. Each of the sub registers 437_1, 437_2,..., 437_N-1, 437_N stores the maximum voltage value for each vertical section.

32A is a conceptual diagram illustrating a process of separating an image signal included in one frame into horizontal sections, and FIG. 32B is an enlarged view of region B shown in FIG. 32A. 33 is a conceptual view illustrating a process of separating one horizontal scanning line into vertical sections. FIG. 34 is a conceptual view illustrating a process of separating a plurality of horizontal scan lines constituting one horizontal section into vertical sections.

Referring to FIG. 32, an image signal input from an image signal source has a predetermined number of horizontal scan lines per frame. For example, in the case of an NTSC system video signal, the number of horizontal scanning lines per frame is 525, and the number of horizontal pixels displayed in one scanning line is 700. Here, the number of horizontal effective scanning lines is 493, and the number of effective horizontal pixels is 658.

The number of pixels of one image display area VDS included in the liquid crystal panel is a * b (a is the number of horizontal pixels, b is the number of vertical pixels, and a and b is a positive integer greater than 1). In this case, a = (number of horizontal pixels) / (number of vertical divisions) and b = (number of horizontal scanning lines) / (number of horizontal divisions) can be displayed.

Referring to FIG. 33, the number of horizontal pixels of one horizontal scanning line is a * M. The a * M pieces may be separated into luminance signals corresponding to a pixels in each vertical section (X1 to XM).

In this manner, as shown in FIG. 34, the luminance signals corresponding to the b horizontal scan lines HL1 to HLb in one horizontal section Yn may be separated into vertical sections X1 to XM, respectively.

Referring to FIG. 31, the maximum voltage detector 434 detects the maximum luminance value of each horizontal section by comparing the luminance values of all pixels included in the b horizontal scanning lines with respect to one horizontal section.

In addition, the maximum voltage detector 434 detects the maximum luminance value in each vertical section by dividing the horizontal section into vertical sections. The detection of the maximum luminance value consists of detecting the maximum value of the voltage level of the luminance signal.

FIG. 35 is a flowchart for describing a step of detecting a maximum luminance value for each image display area illustrated in FIG. 30 in more detail.

30 to 35, the maximum voltage detector 434 initializes the first and second registers 436 and 437 and initializes the first variable n to '1' (step S310).

Subsequently, a process for detecting a maximum voltage value for each vertical section X1 to XM in the nth horizontal section is performed (step S320).

In detail, the second variable m is initialized to '1' (step S321), and the maximum voltage of the mth vertical section Xm included in the nth horizontal section Yn is detected (step S322). The maximum voltage value Vmax_Xm detected in step S322 is stored in the m-th area of the second register 47 (step S323).

Then, the second variable m is increased to '1' (step S324), and it is checked whether M <m to determine whether the maximum voltage value is detected for the last vertical section in the nth horizontal section (step S325). . When M <m is not equal to M <m in step S325, the feedback is fed back to step S322 to detect all the maximum voltage values Vmax_X1 to Vmax_XM for M vertical sections and sequentially store them in the second register 437.

If M <m is checked in step S325, the process of detecting the maximum voltage value for the nth horizontal section is performed (step S330).

Specifically, the detected M maximum voltage values Vmax_X1 to Vmax_XM are compared with each other to detect the maximum voltage value Vmax_Yn in the nth horizontal section Yn (step S332). Subsequently, the detected maximum voltage value Vmax_Yn of the nth horizontal section Yn is stored in the nth region of the first register 436 (step S334).

Then, n, which is the first variable, is increased to '1' (step S346), and it is checked whether N <n to determine whether the maximum voltage value for the last horizontal section is detected (step S348). In step S348, when N <n is checked, the process ends. When it is checked that it is not N <n, the process returns to step S321 to sequentially output the maximum voltage values Vmax_Y1 to Vmax_YN for N horizontal sections. It is detected and stored in the first register 46.

The process of detecting the maximum voltage value (maximum luminance value) for the above-described horizontal and vertical sections is schematically illustrated in FIGS. 36A to 36C.

36A to 36C are conceptual views illustrating a process of detecting maximum voltage values for horizontal and vertical sections.

As shown in FIGS. 30 and 36A, the first horizontal section maximum voltage Vmax_Y1 detected in the first horizontal section Y1 is stored in the first register 436. The M maximum voltage values Vmax_X1 to Vmax_XM detected in the M vertical sections X1 to XM included in the first horizontal section Y1 are sequentially stored in the second register 437_1.

40 and 36B, the second horizontal section maximum voltage Vmax_Y2 detected in the second horizontal section Y2 is stored in the first register 436. The M maximum voltage values Vmax_X1 to Vmax_XM detected in the M vertical sections X1 to XM included in the second horizontal section Y2 are sequentially stored in the second register 437_2.

In this way, as shown in FIG. 36C, the maximum voltage for each horizontal and vertical section is detected up to the Nth horizontal section YN, and the detected maximum voltage value is stored in the first register 436 and the second register 437_N. do.

As described above, the detection method of the maximum voltage for each horizontal and vertical section may be determined in more detail according to the sequential scanning method, interlaced scanning method, face division scanning method, and the like. However, a more detailed process will be well known to those skilled in the art based on the present invention.

Next, the process of controlling the horizontal driver 450 and the vertical driver 460 of the backlight controller 430 will be described, and the process of driving the backlight unit 420 by the horizontal driver 450 and the vertical driver 460 will be described. It explains in detail.

As described above, the maximum voltage value of each horizontal section Y1 to YN is stored in the first register 436, and the maximum voltage value of each vertical section X1 to XM is stored in the second register 437. The maximum voltage values stored in the first register 436 and the second register 437 are sequentially output under the control of the timing controller 433.

FIG. 37 is a flowchart illustrating the dividing driving of the backlight unit illustrated in FIG. 30 in more detail, and FIG. 38 is a timing diagram of maximum voltage values output from the first and second registers of the backlight controller.

29, 37, and 38, the backlight controller 430 initializes the first variable n to '1' (step S410), and the nth horizontal section stored in the first register 436. The maximum voltage value Vmax_Yn of (Yn) is outputted to the horizontal driver 450 (step S420).

Next, the horizontal driver 450 drives the M first discharge electrodes arranged in the nth horizontal section Yn of the backlight unit 420 according to the input maximum voltage value Vmax_Yn (step S430). ). The first discharge electrode has been described as defined by reference numeral 421 in FIG. 28. The first discharge electrodes are electrically connected in common along each column (horizontal line).

Subsequently, the backlight controller 430 is configured to obtain the maximum voltage values Vmax_X1 to Vmax_XM of the M vertical sections X1 to XM corresponding to the nth horizontal section Yn from the second register 437. Output to step 460 (step S440).

Next, the vertical driver 460 drives the M second discharge electrodes arranged in the nth horizontal section Yn of the backlight unit 420 according to the input maximum voltage values Vmax_X1 to Vmax_XM ( Step S450). The second discharge electrode has been described with reference to 422 in FIG. The second discharge electrodes are electrically common connected along each row (vertical line).

Subsequently, the backlight controller 430 increases the variable 'n' as the first variable '1' (step S460), and checks the increased first variable and N (step S460). If it is checked in step S460 that the increased first variable is greater than N, the process ends.

On the other hand, if it is checked in step S460 that the increased first variable is less than or equal to N, it feeds back to step S420.

In this way, the maximum voltage value Vmax_Y1 to Vmax_YN of each horizontal section Y1 to YN and the corresponding vertical section X1 to XM are synchronized with the display of the image signal of one frame on the liquid crystal panel 410. ), The maximum voltage values Vmax_X1 to Vmax_XM are output to the horizontal driver 450 and the vertical driver 460.

The horizontal driver 450 and the vertical driver 460 respectively drive the first and second discharge electrodes disposed in the luminance control region BCS of the backlight unit 420 based on the input maximum voltage value. The brightness is individually controlled for each area.

FIG. 39 is a detailed circuit diagram illustrating the horizontal driver and the vertical driver shown in FIG. 29.

Referring to FIG. 39, the horizontal driver 450 includes a first switching control circuit 451, a first switching circuit 452, and a first transformer circuit 453, so that the maximum voltage values Vmax_Y1, Vmax_Y2,... , Vmax_YN-1, Vmax_YN) are input to drive the first discharge electrodes arranged in the corresponding horizontal section. The first discharge electrode has been described as defined by reference numeral 421 in FIG. 28.

Specifically, the first switching control circuit 451 includes N comparators 451a and a first triangle wave generator 451b arranged in parallel. The first input terminal (positive terminal) and the second input terminal (negative terminal) of the N comparators 451a are connected to the first register 436 and the first triangle wave generator 451b, respectively.

The first switching circuit 452 includes N switches 452a arranged in parallel. Input terminals of the N switches 452a are commonly connected to the inverter 440, and output terminals thereof are connected in parallel to the first transformer circuit 453. The output terminals of the N comparators 451a are connected to the switching terminals of the N switches 452a. The N switches 452a may be configured as a semiconductor switch such as a field-effect transistor (FET) or a bipolar transistor (BJT).

The first transformer circuit 453 includes N transformers 453a arranged in parallel. The primary sides of the N transformers 453a are connected to the output terminals of the N switches 452a, and the secondary sides of the power input terminals Y1_Vin ~ in the horizontal sections Y1 to YN of the backlight unit 420. YN_Vin) is also connected in parallel. The power input terminals Y1_Vin to YN_Vin of each column have been described with reference to FIG. 28.

The N transformers 453a include a boost transformer having a primary and secondary winding ratio of 1: K (1 <K, K is a real number greater than 1).

The vertical driver 460 includes a second switching control circuit 461, a second switching circuit 462, and a second transformer circuit 463. The vertical driver 460 has the same circuit configuration as that of the horizontal driver 450. However, the number of comparators 461a, switches 462a, and transformers 463a respectively configured in the second switching control circuit 461, the second switching circuit 462, and the second transformer circuit 463 is M. It is equal to the number of vertical sections X1 to XM.

Although the triangular wave generator 451b of the first switching control circuit 451 and the triangular wave generator 461b included in the second switching control circuit 461 are illustrated as being separately configured, they are shared by using one triangular wave generator. You may.

40 is a conceptual diagram illustrating waveforms of main nodes of the horizontal driver, and FIG. 41 is a waveform diagram illustrating a change in duty according to a change in the maximum voltage value of the horizontal section.

40 and 41, the maximum voltage value Vmax_Yn of the n-th horizontal section YN input to the horizontal driver 450 is input to the n-th comparator 451a of the first switching control circuit 451. do. The comparator 451a outputs a switching control signal that is an amplitude modulated square wave by comparing the voltage value of the triangular wave, which is a reference voltage, with the input maximum voltage value Vmax_Yn.

The duty of the switching control signal of the square wave output from the comparator 451a varies according to the level of the maximum voltage Vmax. The frequency of the triangle wave output from the triangle wave generator 451b is determined to be b times lower than the frequency of the horizontal sync signal Hsync of the image signal.

The switch 452a is turned on / off by a switching control signal output from the comparator 451a, and applies an AC voltage input from the inverter 440 to the primary side of the transformer 453a. The transformer 453a boosts an AC voltage applied to the primary side and outputs the voltage to the secondary side.

In the above description, only the waveforms of the main node in the operation of the horizontal drive unit, but those skilled in the art can be applied to the waveform of the main node in the operation of the vertical drive unit.

FIG. 42 is a timing diagram for explaining the operation of the horizontal driver shown in FIG. 29, and FIG. 43 is a timing diagram for explaining the operation of the vertical driver shown in FIG.

29 and 42, as the horizontal driver 450 sequentially inputs the maximum voltage values Vmax_Y1 to Vmax_YN for each horizontal section Y1 to YN from the backlight controller 430, the backlight unit ( N horizontal driving voltages Y1_Vin to YN_Vin are sequentially supplied to the power input terminal of the horizontal section Y1 to YN of 420.

29 and 43, the vertical driver 460 receives the M maximum voltage values Vmax_X1 to Vmax_XN for each vertical section Y1 to YN from the backlight controller 430. M vertical driving voltages X1_Vin to XM_Vin are simultaneously input to the power input terminals of the vertical sections X1 to XN of the unit 420.

As described above, when the horizontal driver 450 and the vertical driver 460 operate, the first and second discharge electrodes disposed in each luminance control area BCS of the backlight unit 420 may have a horizontal section Y1. YN) is sequentially divided, and the vertical sections X1 to XM corresponding to the respective horizontal sections Y1 to YN are simultaneously divided and driven.

44 is a conceptual diagram illustrating an example in which the luminance of the luminance control region is controlled and driven by the backlight unit according to the luminance distribution of the image displayed on the liquid crystal panel.

As illustrated in FIG. 44, an image corresponding to two different luminance is displayed on the liquid crystal panel 410. That is, the image IMG_2 of high luminance is displayed in the center region of the screen, and the image IMG-1 of low luminance is displayed in the peripheral region of the screen.

In this case, the backlight unit 420 drives the luminance relatively high in correspondence with the center region where the high brightness image IMG_2 is displayed, and drives the luminance relatively low in the peripheral region. The relatively high driving region has a size larger than that of the high luminance image IMG_2.

As described above, according to the flat panel display of the present invention, the luminance control region BCS of the backlight unit 420 is individually driven according to the luminance characteristic of the image displayed for each image display region VDS of the liquid crystal panel 410. Is done.

As described above, the surface light source device is formed by forming an upper electrode on the front surface of the upper substrate, defining a plurality of lighting regions by defining a region defined by spacers, and forming a lower electrode to correspond to each of the lighting regions. In this way, a partial brightness function can be given to the surface light source device.

Further, by using the surface light source device to partially or brightly adjust the brightness of the light source differently, the brightness of the light source is partially different depending on the characteristics of the image displayed when the image displayed on the display device is partially dark or bright. It can be done differently, so high contrast ratio can be obtained, and power consumption can be reduced with high efficiency.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (41)

A discharge tube including a discharge electrode part in each of the plurality of lighting regions; A power supply source for supplying power to the discharge electrode portions; And And a surface light source controller for individually adjusting the power levels supplied to the discharge electrode portions of the respective lighting regions to individually control the brightness of each of the lighting regions. The surface light source device of claim 1, wherein the surface light source controller adjusts a power level supplied to a discharge electrode of a corresponding lighting region according to characteristics of an image signal. The method of claim 1, wherein the surface light source control unit further comprises a light detecting unit for detecting the ambient illumination, And adjusting the power level supplied to the discharge electrode part based on the light detection level detected from the light sensing part. The surface light source device according to claim 1, wherein the discharge electrode part includes first and second discharge electrodes facing each other, and the first and second discharge electrodes have a flat plate-like structure. The surface light source device according to claim 1, wherein the discharge electrode portion includes first and second discharge electrodes facing each other, and the first and second discharge electrodes have a flat spiral structure. The method of claim 1, wherein the surface light source control unit, A power level controller which receives power supplied from the outside and adjusts a power level supplied to each discharge electrode of the plurality of lighting regions in response to a power level control signal; And And a backlight controller which checks a characteristic of an image signal and generates a power level control signal for adjusting brightness of a lighting area according to the result. The surface light source of claim 6, wherein the discharge electrode unit includes first and second discharge electrodes facing each other, and one of the first and second discharge electrodes is electrically connected to the power level controller. Device. The apparatus of claim 6, wherein the discharge electrode part comprises first, second, third and fourth discharge electrodes arranged in a square shape, and at least two of the first to fourth discharge electrodes are the power level controller. Surface light source device, characterized in that electrically connected to. The surface light source device of claim 8, wherein a frequency of power input to the first to fourth discharge electrodes has a phase different from that of a neighboring electrode. The surface light source device of claim 1, wherein the plurality of lighting areas have a rectangular, circular, or polygonal structure. discharge pipe; An electromotive force generating unit for supplying an induced electromotive force for inducing plasma discharge to the discharge tube; A power supply source providing power to the electromotive force generating unit; A brightness controller configured to be uniformly distributed in the discharge tube to form a plurality of unit brightness control regions in the discharge tube, and to partially adjust the brightness of the corresponding region; And And a surface light source controller for individually controlling brightness of the unit brightness control area by controlling the brightness controller. The surface light source device of claim 11, wherein the surface light source controller individually adjusts the brightness of the unit brightness adjusting area according to the characteristics of the image signal. The method of claim 11, wherein the surface light source control unit further comprises a light detecting unit for detecting the ambient illumination, And controlling the brightness of the unit brightness adjusting area as a whole based on the light detection level detected by the light detecting unit. The method of claim 11, wherein the surface light source control unit, A switching circuit which generates a driving signal for driving the brightness controller in response to the brightness control signal; And And a backlight controller which checks a characteristic of an image signal and generates a brightness control signal for adjusting the brightness of each unit brightness control area according to the result. The surface light source device of claim 11, further comprising a power level controller configured to control a power level of the power supplied to the electromotive force generator. The surface light source device of claim 15, wherein the surface light source controller controls the power level controller to adjust a power level of power supplied to the electromotive force generator according to characteristics of an image signal input from an image signal source. . The method of claim 16, wherein the surface light source control unit further comprises a light sensing unit for sensing the ambient illumination, And controlling the power level adjusting unit to adjust the power level of the power supplied to the electromotive force generating unit based on the light detection level detected by the light detecting unit. The method of claim 11, wherein the electromotive force generating unit, A flat discharge electrode disposed at an edge of the discharge tube; A ferrite core disposed at an edge of the discharge tube; And And a coil wound around the ferrite core, one end of which is connected to the plate discharge electrode, and the other end of which is connected to the power supply source. The surface light source device of claim 11, wherein the brightness controller comprises a plurality of point electrodes uniformly distributed on a rear surface of the discharge tube. The method of claim 11, wherein the brightness control unit, A ferrite core uniformly distributed on the rear surface of the discharge tube; And And a coil wound around the ferrite core. 12. The surface light source device according to claim 11, wherein the discharge tube includes a plurality of spacers partitioning to have a plurality of discharge regions. 22. The apparatus of claim 21, wherein the electromotive force generating unit includes a plurality of sub electromotive force generating units disposed separately for each of the plurality of discharge regions of the discharge tube, and the sub electromotive force generating units supply the power supply as a whole or individually. Surface light source device characterized in that the control. The method of claim 21, wherein the electromotive force generating unit, And planar coil type antenna electrodes respectively disposed in the plurality of discharge regions of the discharge tube. 12. The surface light source device according to claim 11, wherein the discharge tube is a plurality of cylindrical discharge tube. 25. The surface light source device according to claim 24, wherein the brightness controller is one or more transparent electrodes arranged uniformly on the cylindrical discharge tubes. 25. The method of claim 24, further comprising an external electrode disposed outside the cylindrical discharge tube, a ferrite core and a coil wound around the ferrite core, One end of the coil is electrically connected to the external electrode, and the other end is electrically connected to the power supply. 25. The method of claim 24, further comprising an internal electrode disposed inside the cylindrical discharge tube, a ferrite core disposed outside the cylindrical discharge tube and a coil wound around the ferrite core, One end of the coil is electrically connected to the internal electrode, and the other end is connected to the power supply. Display panel; And And a surface light source unit configured to provide light to the display panel, the light of which brightness is partially adjusted, in consideration of characteristics of an image signal supplied to the display panel. 29. The display device according to claim 28, wherein the display panel has two substrates and a liquid crystal layer formed between the two substrates to control transmission of light provided from the surface light source unit. The display panel of claim 28, wherein the display panel includes a plurality of surface-divided image display regions, and the surface light source unit includes a plurality of surface-divided luminance control regions. And the surface light source unit adjusts the brightness of the brightness control area in response to the brightness characteristic of the image displayed in the image display area. The surface light source unit of claim 30, A flat fluorescent lamp having a plurality of discharge electrode pairs; A backlight controller which detects a luminance signal and a synchronization signal from the image signal, and detects a maximum luminance value by comparing luminance values of all pixels of each region for each image display region; A horizontal driver configured to supply power to discharge electrodes arranged in a horizontal direction under the control of the backlight controller; And And a vertical driver configured to supply power to discharge electrodes arranged in a vertical direction under the control of the backlight controller. The method of claim 31, wherein the backlight control unit A luminance signal detector for detecting a luminance signal from the video signal; A synchronization signal detector for detecting horizontal and vertical synchronization signals from the video signal; A timing controller generating a timing control signal based on the horizontal and vertical synchronization signals; A maximum voltage detector detecting a maximum voltage for each horizontal section from the luminance signal in response to the timing control signal, and detecting a maximum voltage for a vertical section corresponding to each horizontal section; A first register for storing a maximum voltage value for the horizontal section; And And a second register configured to store a maximum voltage value of the vertical section for each horizontal section. 33. The display device according to claim 32, wherein the luminance signal detector includes a low pass filter (LPF). The method of claim 31, wherein the horizontal drive unit A first switching control circuit configured to output a first switching control signal by comparing the maximum voltage value of the horizontal section with a reference voltage value; A first switching circuit switched on / off by the first switching control signal to output an AC voltage supplied from an inverter; And And a first transformer circuit for boosting an AC voltage output from the first switching circuit. 35. The display device according to claim 34, wherein the first switching control signal is a square wave. The method of claim 34, wherein the first switching control circuit, A first triangle wave generator for outputting the reference voltage value; And And a plurality of first comparators arranged in parallel to output the first switching control signal by comparing the maximum voltage values of the plurality of horizontal sections with the reference voltage value. The method of claim 31, wherein the vertical drive unit A second switching control circuit configured to output a second switching control signal by comparing the maximum voltage value and the reference voltage value in the vertical section; A second switching circuit switched on / off by the second switching control signal to output an AC voltage supplied from an inverter; And And a second transformer circuit for boosting an AC voltage output from the second switching circuit. 38. The display device according to claim 37, wherein the second switching control signal is a square wave. The method of claim 37, wherein the second switching control circuit, A second triangle wave generator for outputting the reference voltage value; And And a plurality of second comparators arranged in parallel to output the second switching control signal by comparing the maximum voltage values of the plurality of horizontal sections with the reference voltage value. In the control method of the display device comprising a display panel and a surface light source unit for providing light to the display panel, Detecting a luminance signal and a synchronization signal from a video signal supplied from an external video signal source; Detecting a maximum luminance value for each image display area of the display panel; And And dividing and driving the surface light source unit based on the maximum luminance value of each luminance control area included in the surface light source unit. 41. The method of claim 40, wherein detecting the maximum luminance value comprises: Detecting a maximum voltage value for each vertical section in every horizontal section; And And detecting a maximum voltage value for each horizontal section.

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