KR100918813B1 - Flat panel display with local dimming technology - Google Patents

Abstract

The present invention provides a surface light source device for locally adjusting brightness for each unit discharge cell, wherein the unit discharge cell is spaced apart from and supported by an upper substrate and a lower substrate covering the unit discharge cell up and down, and the upper substrate and the lower substrate. A partition member that maintains a discharge space therein, a scan electrode installed inside the unit discharge cell, and a data electrode provided outside the unit discharge cell, wherein the scan electrode and the data electrode are specified. When an electric field is generated between the data electrodes, a discharge is formed in a discharge space of a specific unit discharge cell corresponding to the specific scan electrode. Accordingly, the contrast ratio and the motion blur phenomenon of the screen of the liquid crystal display are improved by using the surface light source including the unit discharge cells that can independently adjust the brightness.

Local brightness control, selective brightness control, Local Dimming Control, Motion Blur, LCD, LCD, Backlight, Surface Light Source

Description

Surface light source device with adjustable brightness by selection area {FLAT PANEL DISPLAY WITH LOCAL DIMMING TECHNOLOGY}

The present invention relates to a surface light source device capable of adjusting brightness for each selected area, and more particularly, to generate an electric field independently in a discharge space of each unit discharge cell in a surface light source device including a plurality of unit discharge cells. The present invention relates to a surface light source device capable of adjusting brightness for each selected region by using a scan electrode located inside each unit discharge cell and a data electrode located outside.

In recent years, as the use of high-definition television has been expanded and the performance of computers has been improved, the importance of a display device (or a video display device) has been highlighted.

The display device includes a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display panel (PDP), and the like.

Cathode ray tubes having the longest history among such display devices are being replaced by flat panel displays (FPDs) which are relatively thin, light and low in power consumption due to their bulky size and high power consumption. A flat panel display is a thin display having a thickness of a few centimeters (cm) and a few millimeters (mm).

Such flat panel displays are classified into a non-emissive type that requires a light source separately from an emissive type that can emit light by itself. The light emitting type includes a plasma display panel (PDP), an organic light emitting display (OLED), a field emission display (FED), and the light receiving type includes a liquid crystal display (LCD). LCDs belonging to the light-receiving type cannot display an image without an external light source, and therefore, a back light unit (BLU), which is a separate light source, is necessary. These BLUs have a cold cathode fluorescent lamp (CCFL) method in which ultraviolet rays emitted from mercury gas excited by electrons emitted by a high voltage electric field collide with phosphors to generate visible light, and electric luminescence generated when a voltage is applied to a semiconductor. Light sources such as an LED (light emitting device) method using a phenomenon and a flat fluorescent lamp (FFL) method for emitting light by diffusing light by ultraviolet rays generated from gas discharge are widely used.

Among them, the FFL method is a surface light source method. Compared with the conventional line light source method, since only one lamp is used, the number of parts is greatly reduced, and the manufacturing process of BLU and LCD panels can be automated, and mercury discharge is possible. Because it is environmentally friendly and the light source itself has a surface shape, there is an advantage that can reduce the amount of a plurality of optical sheets used to eliminate dark lines.

1 is a plan view showing the configuration of a backlight unit 100 of a CCFL (or EEFL) type according to the prior art.

Referring to FIG. 1, the backlight unit 100 may include an electrode unit 101 and an encapsulation tube 102. In detail, the encapsulation tube 102 is in the form of a long rod and may be included in the backlight unit 100 in a plurality at regular intervals. In addition, the electrode unit 101 may be present at both ends of the encapsulation tube 102. Here, after exhausting the air inside the encapsulation tube 102 to the outside, at least one discharge gas of argon (Ar), helium (He), neon (Ne), xenon (Xe), mercury (Hg) is filled The phosphor layer may be formed on the inner surface of the encapsulation tube 102.

Subsequently, when voltage is applied to the electrode portions 101 at both ends of the encapsulation tube 102, ultraviolet rays are generated in the encapsulation tube 102, and visible rays are generated when the generated ultraviolet rays are applied to the phosphor layer, thereby generating a liquid crystal display device ( Liquid crystal display (LCD) allows an image to be displayed.

Liquid crystal (liquid crystal) refers to a liquid material having a crystallinity is directional by the difference in the electric field (Electric field) between the upper substrate and the lower substrate. The liquid crystal rotated by the potential difference functions as a path through which the light supplied from the light source located at the rear side passes and implements color by adding a color filter. Since the LCD is a hold-type display that continuously displays one image data for one frame, it provides a clear image in the case of a still image but causes a motion blur in a moving image. do. In addition, the light supplied from the light source cannot be completely blocked due to a problem due to the optical arrangement of the liquid crystal, and thus it is difficult to realize a clear image, that is, a high contrast ratio, compared to the light emitting display.

In order to prevent such motion blur phenomenon, a local dimming control technique can be used. Local brightness control technique refers to a technique that can drive the backlight separately and control the change of brightness in the divided region individually (independently). Therefore, a method of reducing the Motion Blur phenomenon and improving the contrast ratio by locally adjusting the brightness through the Backsight Scanning method of driving the backlight sequentially and controlling the on-off is controlled. It is being studied.

However, in the case of CCFL and EEFL as shown in FIG. 1, which is the light source most commonly used as a conventional backlight, both types of line light sources can be applied to the backsite scanning method, but selective brightness adjustment for each area is impossible. The disadvantage is that.

On the other hand, LED light source, which is attracting the most attention recently, has been applied to various fields such as mobile phones, and it is possible to adjust the local brightness and show excellent color expression, but the price is expensive and the luminous efficiency does not overcome the serious disadvantages of heat generation. And since it is a point light source has a disadvantage of having to use various types of optical sheet.

Accordingly, an object of the present invention is to provide a surface light source that can improve the contrast ratio and the motion blur phenomenon of a screen provided through a liquid crystal display device.

The surface light source is constituted by the upper substrate, the lower substrate, and the partition member, and the partition member itself includes an internal electrode and discharges in the unit discharge cell by an electric field between the internal electrode and an external electrode having a different polarity. An object of the present invention is to provide a surface light source capable of independently adjusting brightness for each unit discharge cell divided by a partition member.

In order to achieve the object of the present invention as described above, and to perform the characteristic functions of the present invention described below, the characteristic configuration of the present invention is as follows.

According to an aspect of the present invention, a surface light source device including at least one unit discharge cell and configured to locally adjust brightness for each unit discharge cell, the upper substrate and the lower substrate covering the unit discharge cells up and down, A partition member for separating and supporting an upper substrate and the lower substrate to maintain a discharge space in the unit discharge cell, a scan electrode provided inside the unit discharge cell, and a data electrode provided outside the unit discharge cell. When an electric field is generated between a specific scan electrode among the scan electrodes and a specific data electrode among the data electrodes, a discharge is formed in a discharge space of a specific unit discharge cell corresponding to the specific scan electrode. An apparatus is provided.

According to the present invention, it is possible to improve the contrast ratio and the motion blur phenomenon of the screen of the liquid crystal display by using a surface light source consisting of unit discharge cells, each of which is independently adjustable brightness.

In addition, according to the present invention, by providing a surface light source that can selectively adjust the brightness, it is possible to lower the power consumed in the area that is not necessary when implementing the screen has the effect of lowering the overall power consumption.

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

FIG. 2A is a cross-sectional view showing the configuration of the discharge cell 200 in the surface light source according to the embodiment of the present invention, and FIG. 2C is a plan view emphasizing the partition member of the discharge cell.

For reference, the structure of the discharge cell described in the present invention is preferably a surface light source, but is not necessarily limited to this, it will be understood that it can be applied to other types of light sources within a similar range comprehensively.

Referring to FIG. 2A, the discharge cell 200 is inserted into the upper substrate 202, the lower substrate 204, the partition member 206 formed between the upper substrate 202 and the lower substrate 204 to form a discharge space. It can be seen that it includes a scan electrode 208 formed on the partition member 206, a data electrode 210 formed outside the upper substrate 202, and the like. Here, although the data electrode 210 is illustrated as being formed outside the upper substrate 202, it is understood that the data electrode 210 may be formed outside the lower substrate 204.

Referring to FIG. 2A, it can be seen that the scan electrode 208 and the data electrode 210 are paired to generate an electric field in the unit discharge cell, and thus discharge occurs in the internal space of the unit discharge cell. That is, the scan electrode 208 is included in the bulkhead structure itself, which is mass-produced separately, and an electric field is formed between the scan electrode 208 and the scan electrode 208 and external electrodes having different polarities (ie, data electrodes 210). Discharge is generated in the unit discharge cell. If the scan electrode 208 and the data electrode 210 are all located in the discharge cell 200, discharge interference with other cells may occur. It may be difficult to discharge by the selected region to be described in the following.

2B, it can be seen that the scan electrode 208 is provided on one side of the partition member 206, and the dielectric layer 209 covers the scan electrode 208. Here, the scan electrode 208 is printed and then fired through screen printing, and the dielectric layer 209 is laminated on the fired scan electrode 208 using screen printing or dry film resist (DFR). It may be formed by a laminating method or the like, but is not necessarily limited thereto. Meanwhile, the scan electrode 208 may be formed of a conductive material such as an alloy, a metal compound, carbon, as well as pure metal, but is not necessarily limited thereto.

Referring to FIG. 2C, the partition member 206 may include a horizontal partition member 206a installed horizontally and a vertical partition member 206b installed vertically, and the scan electrode 208 may be a vertical partition member 206b. Can be installed on the side of the. However, since the installation position of the scan electrode 208 is for the convenience of the user, if the installation condition with the data electrode to be described later is satisfied, it may be installed on the horizontal partition member 206a instead of the vertical partition member 206b. .

3 is a view showing the configuration of a discharge cell 300 according to another embodiment of the present invention.

Referring to FIG. 3, the unit discharge cell 300 is modified by slightly modifying the embodiment of FIG. 2 in which the scan electrode is installed on the partition member 306 inserted between the upper substrate 302 and the lower substrate 304. It can be seen that the scan electrode 308 is provided on the inner lower surface of the substrate. In addition, the data electrode 310, which serves as a pair with the scan electrode 308, may be installed at an upper side of the upper substrate 302, but may be provided at a lower side of the lower substrate 304. As mentioned above.

The scan electrode 308 and the data electrode 310 may be positioned in a diagonal direction with respect to the discharge cell 300 so that the discharge cells 300 may be uniformly discharged within the discharge cell 300. no.

4 is a perspective view showing the overall configuration of the surface light source device 200 according to an embodiment of the present invention.

Referring to FIG. 4, a plurality of partition members 206 are inserted in parallel or vertically at regular intervals between the upper substrate 202 and the lower substrate 204 to form respective unit discharge cell spaces, as described above. It can be seen that the scan electrode 208 and the dielectric layer 209 are formed on the side surface of the partition member 206, and the data electrode 210 is provided on the upper side of the upper substrate 202.

Specifically, when the aggregate form of the unit discharge cells included in the surface light source device 200 is m * n matrix form, the data electrode 210 passes through the upper region of each of the unit discharge cells arranged in m rows. In order to generate a discharge in the n connection lines 210a and m unit discharge cells covered by each of the connection lines 210a serving to supply a voltage from the outside in a long position in the upper region of the upper substrate 202. Each of the connection lines 210a may include m detailed lines 210b each of which is divided into m-branches so that each of the divided portions functions as the data electrode 210. Of course, the m connection lines 210a may be installed long to cover each of the unit discharge cells arranged in n columns, and the connection may be performed to cause discharge to the n unit discharge cells included in each column. N details lines 210b may be drawn from the line 210a.

The connection line 210a of the data electrode 210 is provided in a direction orthogonal to the installation direction of the scan electrode 208 or the detail line 210b, and the detail line 210b serving as the data electrode is the scan electrode 208. It is installed in the direction parallel to). Therefore, the electric field may be uniformly formed in the discharge cell by the detail line 210b formed in parallel with the scan electrode 208.

Here, a polymer having a non-conductor property is formed in the lower portion of the connection line 210a that connects the detail line 210b, which is a portion which functions as an actual data electrode, to minimize the effect of discharge interference with other discharge cells. Might apply.

The sequential electric field may be applied to the scan electrode 208 on the same time axis as the LCD, and this corresponds to a method of sequentially turning on and off the LCD BLU from the top to the bottom. According to this, the motion blur phenomenon can be reduced by not allowing the repetition period when sequentially on-off affects the liquid crystal reaction speed.

FIG. 5 is an exemplary diagram illustrating an example of realizing a local dimming control function using the surface light source device 200 according to the present invention shown in FIG. 4.

Referring to FIG. 5, the data electrode 210 illustrated in FIG. 4 includes data electrodes 2101, 2102, 2103, 2104, and 2105, and the scan electrode 208 includes scan electrodes 2021, 2082, 2083, and 2084. It can be seen that it contains. For reference, the number of data electrodes and scan electrodes shown in FIG. 5 is merely illustrative.

In the structure in which the scan electrode 208 and the data electrode 210 are arranged as described above, when a signal is applied only to the specific scan electrode 2082 and the specific data electrode 2102, the gray area is displayed as shown in FIG. 5. The discharge occurs only in the unit discharge cell. Here, the brightness may be adjusted by changing the electric field. In this case, operation control of the scan electrode 208 and the data electrode 210 is performed by a data processing unit described later with reference to FIG. 6.

FIG. 6 is a diagram schematically illustrating an operation control mechanism of the surface light source device 200 according to an embodiment of the present invention.

Referring to FIG. 6, it is understood that each of the four scan electrodes 208 and the fourteen data electrodes 210 is controlled by a control signal output through the image processor 602 and the data processor 604. Can be.

Specifically, when an image signal is input to the image processor 602 positioned between the graphic card and the liquid crystal panel, the image processor 602 converts the input image signal into a signal for input to the liquid crystal panel. The image signal converted by the image processor 602 is input to the data processor 604 and analyzed. For example, the data processor 604 selects a partial luminance change position among the image signals converted by the image processor 602. An electric field is applied to the scan electrode 208 and the data electrode 210 corresponding to the region to form a discharge, thereby finally implementing an image through the liquid crystal.

As described above, the data processing unit 604 performs control of each of the scan electrode 208 and each of the data electrode 210, and simultaneously transmits an image signal to the liquid crystal display 606. That is, when the screen is provided to the liquid crystal display 606 through the data processing unit 604, the scan electrode 208 and the data electrode 210 are adapted to the change of the object displayed on the screen of the liquid crystal display 606. By appropriately controlling the same time, it is possible to improve the contrast ratio and improve the motion blur phenomenon.

Although the present invention has been shown and described with reference to preferred embodiments as described above, it is not limited to the above embodiments and various modifications made by those skilled in the art without departing from the spirit of the present invention. Modifications and variations are possible. Such modifications and variations are intended to fall within the scope of the invention and the appended claims.

1 is a plan view showing the configuration of a CCFL backlight unit 100 according to the prior art.

2A is a cross-sectional view illustrating a configuration of a discharge cell 200 according to an embodiment of the present invention, FIG. 2B is a cross-sectional view illustrating a configuration of a scan electrode, and FIG. 2C is a plan view emphasizing a partition member in the configuration of the discharge cell. to be.

3 is a view showing the configuration of a discharge cell 300 according to another embodiment of the present invention.

4 is a perspective view showing the overall configuration of the surface light source device 200 according to an embodiment of the present invention.

FIG. 5 is an exemplary diagram illustrating an example of realizing a local dimming control function using the surface light source device 200 according to the present invention shown in FIG. 4.

FIG. 6 is a diagram schematically illustrating an operation control mechanism of the surface light source device 200 according to an embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

202 and 302: upper substrate

204 and 304: lower substrate

206, 306: partition member

208 and 308 scan electrodes

210, 310: data electrode

209: dielectric layer

602: an image processing unit

604: a data processing unit

606: liquid crystal display

Claims (17)

A surface light source device comprising at least one unit discharge cell and configured to locally adjust brightness for each unit discharge cell. An upper substrate and a lower substrate covering the unit discharge cells up and down; A partition member for separating and supporting the upper substrate and the lower substrate to maintain a discharge space in the unit discharge cell; A scan electrode provided inside the unit discharge cell, and Including a data electrode provided on the outside of the unit discharge cell, And when an electric field is generated between a specific scan electrode of the scan electrodes and a specific data electrode of the data electrodes, a discharge is formed in a discharge space of a specific unit discharge cell corresponding to the specific scan electrode. The method of claim 1, And the specific unit discharge cell has a structure including the specific scan electrode. The method of claim 1, And the scan electrode on the partition member. The method of claim 1, And the scan electrode is positioned in the vicinity of the partition member. The method according to claim 3 or 4, And the scan electrode and the data electrode are disposed substantially parallel to each other. The method of claim 5, And a dielectric layer is formed on the scan electrode. The method of claim 1, Wherein the number of unit discharge cells is m * n, and the unit discharge cells are collectively present in a matrix of m * n. The method of claim 7, wherein The data electrode is a surface light source device comprising a connection line which is a portion directly connected to the power source and a detailed line branched from the connection line. The method of claim 8, The surface light source device, characterized in that there are n connection lines and m detailed lines are branched per connection line. The method of claim 9, And each of the connection lines is disposed to cross the m unit discharge cells outside of m neighboring unit discharge cells. The method of claim 10, M detailed lines branched into each of the connection lines are branched into each of m unit discharge cells intersecting the connection lines. The method of claim 11, The connection line and the detail line is a surface light source device, characterized in that located above the upper substrate. The method of claim 12, And a polymer is inserted between the connection line and the upper substrate. The method of claim 11, The connection line and the detail line is a surface light source device, characterized in that located below the lower substrate. The method of claim 14, And a polymer is inserted between the connection line and the lower substrate. The method of claim 11, And an electric field is generated between the detail line portion of the specific data electrode and the specific scan electrode. The method of claim 16, And controlling the brightness of the light in the specific unit discharge cell by adjusting the magnitude of power applied to the specific data electrode and the specific scan electrode.

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