KR20080040907A - Display device - Google Patents

Abstract

A display device is provided to enable a light emitting panel to emit light in a dummy area, which is not overlapped with a first effective area, to provide the uniform intensity of light in the entire of the first effective area of the display panel, thereby improving the brightness uniformity of a screen realized in the display panel. A display device(100) comprises a display panel(10) and a light emitting panel(12). A diffusing plate(14) is positioned between the display panel and the light emitting panel to diffuse light emitted from the light emitting panel. The diffusing plate is disposed at a predetermined distance away from the light emitting panel. The display panels includes a TFT(Thin Film Transistor) substrate(16), a color filter substrate(18), and a liquid crystal layer. The PCB(Printed Circuit Board) of the display panel is connected to each of driving packages(201,221). The display panel displays an actual image on a first effective area(24). The light emitting panel has a second effective area(26) larger than the first effective area. The light emitting panel includes a first substrate(28) and a second substrate(30). The light emitting panel emits a visible ray in the second effective area and forms plural pixels on the second effective area to control the intensity of radiation individually by pixel.

Description

Display device {DISPLAY DEVICE}

1 is an exploded perspective view of a display device according to an exemplary embodiment.

2 is a partially exploded perspective view of a light emitting panel of a display device according to an exemplary embodiment of the present invention.

3 is a partial cross-sectional view of a light emitting panel of a display device according to an exemplary embodiment of the present invention.

4 and 5 are perspective views schematically illustrating an electron emission unit of a light emitting panel of a display device according to an exemplary embodiment of the present invention.

6 is a plan view schematically illustrating an electron emission unit of a light emitting panel.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to a display device capable of displaying a uniform luminance in an effective area of a display panel by improving a structure of a light emitting device.

BACKGROUND ART A light emitting device having an electron emitting portion and a driving electrode on a rear substrate, a fluorescent layer and an anode electrode on a front substrate, and emitting a visible light by exciting a fluorescent layer with electrons emitted from the electron emitting portion is known. The light emitting device can be used as a light source of the display device.

The light emitting device may be disposed at a predetermined distance from the display panel for the purpose of installing a diffusion plate. In this case, a part of the light emitted from the edge of the light emitting surface is spread to the periphery so as not to reach the display panel. Therefore, when the screen implemented in the display panel is observed, the edge luminance decreases.

In addition, the light emitting device has a problem that it is difficult to meet the improvement of the image quality required for the display device, for example, to increase the dynamic contrast, because the light emitting device is configured to display the same luminance when the display device is driven. .

Accordingly, an aspect of the present invention is to provide a display device capable of displaying a uniform luminance in an effective area of a display panel by improving a structure of a light emitting device.

In addition, the present invention is to provide a display device that can increase the dynamic contrast ratio of the screen by dividing the light emitting surface of the light emitting device into a plurality of areas and independently controlling the light emission intensity for each divided area.

A display device according to the present invention includes a display panel for displaying an image and a light emitting panel for providing light to the display panel, wherein the light emitting panel is provided on an inner surface of the first substrate and the second substrate facing each other and the first substrate. And an effective area having an area larger than the effective area of the display panel, including a driving electrode and an electron emission unit, and a fluorescent layer and an anode electrode provided on an inner surface of the second substrate.

The display panel may include a first effective area, the light emitting panel may include a second effective area, and the second effective area may include a dummy area that does not overlap the first effective area along an edge of the first effective area. .

The driving electrode may include scan electrodes and data electrodes formed along a direction crossing each other while maintaining insulation from each other, and the electron emission part may be electrically connected to any one of the scan electrode and the data electrode.

At least one scan electrode and at least one data electrode are positioned in the dummy region, and at least one scan electrode positioned in the dummy region is applied with the same voltage as the scan electrode positioned inside thereof, and at least one positioned in the dummy region The data electrode may be applied with the same voltage as the data electrode positioned inside the data electrode.

For this purpose, the at least one scan electrode positioned in the dummy region and the scan electrode positioned inside thereof may have an integrated end portion, and the at least one data electrode positioned in the dummy region and the data electrode positioned inside thereof may also be integrated. It may have an end portion.

The display device may further include a diffusion plate spaced apart from the light emitting panel between the display panel and the light emitting panel. When the display panel includes the first pixels, the light emitting panel includes a plurality of second pixels smaller than the first pixels in a combination of scan electrodes and data electrodes, and independently controls the light emission intensity for each second pixel. The display panel may be a liquid crystal display panel.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is an exploded perspective view of a display device according to an exemplary embodiment.

Referring to FIG. 1, the display device 100 according to the present exemplary embodiment includes a display panel 10 displaying an image and a light emitting panel 12 positioned behind the display panel 10 and providing light to the display panel 10. It includes. A diffusion plate 14 may be disposed between the display panel 10 and the light emitting panel 12 to disperse the light emitted from the light emitting panel 12, and the diffusion plate 14 may be disposed between the light emitting panel 12 and the light emitting panel 12. Are spaced apart.

The display panel 10 may be a liquid crystal display panel. In this case, the display panel 10 includes a TFT substrate 16 on which a plurality of thin film transistors (TFTs) are formed, a color filter substrate 18 positioned on the TFT substrate 16, and the substrates 16. And a liquid crystal layer (not shown) injected between 18). Polarizers (not shown) are attached to the upper portion of the color filter substrate 18 and the lower portion of the TFT substrate 16 to polarize light passing through the display panel 10.

A data line is connected to a source terminal of each TFT, a gate line is connected to a gate terminal, and a pixel electrode made of a transparent conductive film is connected to a drain terminal. When electrical signals are input from the printed circuit boards 20 and 22 to the gate line and the data line, respectively, electrical signals are input to the gate terminal and the source terminal of the TFT, and the TFT is turned on or off depending on the signal input. The electrical signal required for driving the pixel electrode is output to the drain terminal.

The color filter substrate 18 forms RGB pixels which are color pixels in which a predetermined color is expressed while light passes, and a common electrode made of a transparent conductive film is formed on the entire surface. When power is applied to the gate terminal and the source terminal of the TFT and the TFT is turned on, an electric field is formed between the pixel electrode and the common electrode. By this electric field, the arrangement angle of the liquid crystal injected between the TFT substrate 16 and the curly filter substrate 18 is changed, and the light transmittance is changed for each pixel according to the changed arrangement angle.

The printed circuit boards 20 and 22 of the display panel 10 are connected to the respective driving IC packages 201 and 221. In order to drive the display panel 10, the gate printed circuit board 20 transmits a gate driving signal, and the data printed circuit board 22 transmits a data driving signal.

Through the above driving process, the display panel 10 displays an actual image in the first effective area 24. The light emitting panel 12 includes a second effective area 26 having a larger area than the first effective area 24, and emits light toward the display panel 10 from the second effective area 26.

The light emitting panel 12 includes a first substrate 28 on which an electron emission unit (not shown) including a driving electrode and an electron emission unit is formed, and a second substrate on which a light emission unit (not shown) including a fluorescent layer and an anode electrode is formed. (30). The edges of the first substrate 28 and the second substrate 30 are integrally bonded by a sealing member (not shown), and then the inside thereof is exhausted to form a vacuum container.

The light emitting panel 12 is configured to not only emit visible light in the second effective area 26 but also form a plurality of pixels in the second effective area 26 to independently control the light emission intensity of each pixel. The second effective area 26 is defined as an area of the light emitting panel 12 in which an electron emission unit and a light emitting unit are provided to emit actual visible light.

2 and 3 are partial exploded perspective and partial cross-sectional views of a light emitting panel of a display device according to an exemplary embodiment of the present invention, respectively.

In the light emitting panel 12, the electron emission unit 32 is formed of any one of a field emission array type, a surface-conducting emission type, a metal-insulating layer-metal type, and a metal-insulating layer-semiconductor type. Figure 3 shows the field emission array type as an example. The light emitting panels shown in Figs. 2 and 3 are for illustrating the present invention, but the present invention is not limited thereto.

2 and 3, the electron emission unit 32 includes first and second electrodes 36 and 38 formed in a stripe pattern along a direction crossing each other with the insulating layer 34 interposed therebetween. ) And electron emission parts 40 formed in the first electrode 36 at each intersection region of the first electrode 36 and the second electrode 38. The second electrodes 38 and the insulating layer 34 form openings 381 and 341 corresponding to the electron emission parts 40.

The first electrode 36 becomes a cathode electrode for supplying current to the electron emission part 40, and the second electrode 38 forms an electric field by a voltage difference with the cathode electrode, thereby inducing electron emission. do. One of the first electrode 36 and the second electrode 38 receives a scan driving voltage to function as a scan electrode, and the other electrode receives a data driving voltage to function as a data electrode.

The electron emission part 40 may be made of materials emitting electrons, for example, carbon-based materials or nanometer-sized materials when an electric field is applied in a vacuum. The electron emission part 40 may include, for example, a material selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, fullerenes (C ₆₀ ), silicon nanowires, and combinations thereof. .

In the above-described structure, one intersection area of the first electrode 36 and the second electrode 38 corresponds to one pixel area of the light emitting panel 12, or two or more crossing areas are one pixel area of the light emitting panel 12. It can correspond to. In the second case, two or more first electrodes 36 and / or second electrodes 38 positioned in one pixel area are electrically connected to each other to receive the same driving voltage.

Next, the light emitting unit 42 includes a fluorescent layer 44 and an anode electrode 46 positioned on one surface of the fluorescent layer 44. The fluorescent layer 44 may be formed of a white fluorescent layer, and may be formed in the entire effective area of the second substrate 30, that is, the entire second effective area, or may be divided into a predetermined pattern such that one white fluorescent layer is positioned in each pixel area. Can be located.

On the other hand, the fluorescent layer 44 may be composed of a combination of red, green and blue fluorescent layers, these fluorescent layers may be divided into a predetermined pattern in one pixel area. 2 and 3 illustrate a case where a white fluorescent layer is positioned in an effective region of the second substrate 30, that is, the entire second effective region.

The anode electrode 46 may be formed of a metal film such as aluminum covering the surface of the fluorescent layer 44. The anode electrode 46 reflects the visible light emitted toward the first substrate 28 of the visible light emitted from the fluorescent layer 44 toward the second substrate 30 to increase the luminance of the light emitting surface.

In addition, spacers 48 are disposed between the first substrate 28 and the second substrate 30 to support the compressive force applied to the vacuum container and to keep the gap between the substrates 28 and 30 constant. In FIG. 2, one spacer 48 is illustrated for convenience.

The above-described light emitting panel 12 forms a plurality of pixels by the combination of the first electrode 36 and the second electrode 38, and is formed on the first electrode 36 and the second electrode 38 from the outside of the vacuum container. A driving voltage of is applied, and a direct current voltage of an amount of thousands of volts or more is applied to the anode electrode 46 and driven.

Then, in the pixels where the voltage difference between the first electrode 36 and the second electrode 38 is greater than or equal to the threshold, an electric field is formed around the electron emission part 40, and electrons are emitted therefrom, and the emitted electrons are attracted to the anode voltage to correspond. It hits the fluorescent layer 44 site to emit light. The emission intensity of the fluorescent layer 44 for each pixel corresponds to the electron beam emission amount of the corresponding pixel.

Referring back to FIG. 1, the light emitting panel 12 forms fewer pixels than the display panel 10 in an area overlapping the first effective area 24. Thus, one pixel of the light emitting panel 12 corresponds to two or more pixels of the display panel 10. Each pixel of the light emitting panel 12 may emit light corresponding to the highest gray level among the pixels of the display panel 10 corresponding thereto, and the light emitting panel 12 may express 2 to 8 bits of gray level for each pixel. have.

For convenience, a pixel of the display panel 10 is called a first pixel, a pixel of the light emitting panel 12 is called a second pixel, and a plurality of first pixels corresponding to one second pixel is called a first pixel group. . In the driving process of the light emitting panel 12, a signal controller (not shown) for controlling the display panel 10 detects the highest gray level among the first pixels of the first pixel group, and according to the detected gray level, the second pixel. The method may include calculating a grayscale required for light emission, converting the grayscale into digital data, and generating a driving signal of the light emitting panel 12 using the digital data.

A scanning printed circuit board (not shown) and a data printed circuit board (not shown) of the light emitting panel 12 are connected to the respective driving IC packages 501 and 521. In order to drive the light emitting panel 12, the scan printed circuit board transmits a scan drive signal, and the data printed circuit board transmits a data drive signal. One of the above-described first electrode 36 and the second electrode 38 receives a scan driving signal, and the other electrode receives a data driving signal.

As a result, the second pixel of the light emitting panel 12 emits light with a predetermined gray level in synchronization with the first pixel group when an image is displayed in the corresponding first pixel group. That is, the light emitting panel 12 independently controls the light emission intensity for each pixel to provide light of an appropriate intensity to the pixels of the display panel 10 corresponding to each pixel. Therefore, the display device 100 of the present exemplary embodiment can increase the dynamic contrast ratio of the screen, and can realize a clearer picture quality.

In addition, as the light emitting panel 12 includes a second effective area 26 having an area larger than the first effective area 24, the light emitting panel 12 provides light of uniform intensity to the entire display panel 10. can do. In this case, the second effective area 26 includes a dummy area that does not overlap the first effective area 24 along the edge of the first effective area 24, and the dummy area is driven together with the pixels inside the dummy area. Dummy pixels may be formed.

4 and 5 are schematic perspective views illustrating an electron emission unit of a light emitting panel.

4 and 5, when the cross region of the first electrode 36 and the second electrode 38 constitutes one pixel, the dummy region outside the first effective region 24 may include at least one agent. One electrode 36 ', 36 "and at least one second electrode 38', 38" are positioned. 4 and 5, one first electrode 36 ′ and 36 ″ are positioned outside the left and right sides of the first effective region 24, respectively, and one second outside the upper and lower sides of the first effective region 24. The case where the electrodes 38 ', 38 "are located is shown.

Referring to FIG. 4, the first electrode 36 ′ positioned in the dummy region receives the same voltage Vd as the neighboring first electrode 36 positioned inside thereof, and the second electrode positioned in the dummy region. 38 'may also receive the same voltage Vs as the neighboring second electrode 38 positioned inside thereof.

On the other hand, referring to FIG. 5, the first electrode 36 ″ positioned in the dummy region is integrated with an end of the neighboring first electrode 36 positioned inside thereof, and receives the same voltage through the dummy electrode. The second electrode 38 ″ positioned at the end thereof is integrated with a neighboring second electrode 38 positioned at the inner side thereof, and thus may receive the same voltage.

6 is a plan view schematically illustrating an electron emission unit of a light emitting panel. In both cases described above, the dummy pixels positioned in the dummy region function as one pixel by receiving the same driving voltage as the pixel positioned inside thereof. In FIG. 6, the dummy pixels functionally integrated with the pixels inside thereof are grouped by a thick line and represented as one block.

As such, when the light emitting panel 12 is disposed at a predetermined distance from the display panel 10, the light emitting panel 12 may provide light of uniform intensity to the whole of the display panel 10 through visible light emission in the dummy area. As a result, the display panel 10 may display a screen in which the luminance uniformity is improved in the entire first effective area 24.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

According to the present invention, the light emitting panel emits light in a dummy area that does not overlap the first effective area, thereby providing light of uniform intensity to the entire first effective area of the display panel. Accordingly, the display device according to the present invention can increase the luminance uniformity of the screen implemented in the display panel, and can improve display quality by increasing the dynamic contrast ratio by driving the pixels for each pixel.

Claims (9)

A display panel displaying an image; A light emitting panel providing light to the display panel Including, The light emitting panel includes a first substrate and a second substrate disposed to face each other, a driving electrode and an electron emission unit provided on an inner surface of the first substrate, and a fluorescent layer and an anode electrode provided on an inner surface of the second substrate. A display device having an effective area of an area larger than the effective area of a panel. The method of claim 1, The display panel includes a first effective area, the light emitting panel includes a second effective area, and the second effective area includes a dummy area that does not overlap the first effective area along an edge of the first effective area. Display device. The method of claim 2, And a scan electrode and a data electrode formed along the direction in which the driving electrode is insulated from each other while maintaining the insulation, and the electron emission part is electrically connected to any one of the scan electrode and the data electrode. The method of claim 3, And the at least one scan electrode and the at least one data electrode are in the dummy area. The method of claim 4, wherein The at least one scan electrode positioned in the dummy region is applied with the same voltage as the scan electrode positioned inside thereof, and the at least one data electrode positioned in the dummy region has the same voltage as the data electrode positioned inside thereof. Authorized display device. The method of claim 5, And an end portion in which the at least one scan electrode and a scan electrode positioned inside thereof are integrated, and an end portion in which the at least one data electrode and a data electrode positioned inside thereof are integrated. The method according to any one of claims 1 to 6, And a diffuser plate spaced apart from the light emitting panel between the display panel and the light emitting panel. The method of claim 3, The display panel includes first pixels, And a light emitting panel including a plurality of second pixels less than the first pixels by combining the scan electrodes and the data electrodes, and independently controlling light emission intensity for each second pixel. The method according to claim 1 or 8, A display device wherein the display panel is a liquid crystal display panel.

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