KR101343567B1

KR101343567B1 - field emission device

Info

Publication number: KR101343567B1
Application number: KR1020100043527A
Authority: KR
Inventors: 정진우; 송윤호; 김동일; 김재우; 강준태
Original assignee: 한국전자통신연구원
Priority date: 2009-12-21
Filing date: 2010-05-10
Publication date: 2013-12-20
Also published as: KR20110073188A

Abstract

The present invention relates to a field emission device, comprising: a plurality of cathode electrodes formed on an upper surface of a first substrate; An anode formed on a lower surface of a second substrate and disposed to face the cathode; A fluorescent film formed of alternating red, green, and blue patterns formed on the anode electrode, wherein the red, green, and blue patterns are arranged in an oblique direction; And a plurality of emitters formed on the plurality of cathode electrodes to correspond to the red, green, and blue patterns. According to the present invention, by using the electroluminescent device having a fast response speed as a backlight unit, it is possible to prevent the color breaking phenomenon in the color sequential driving method. In addition, by using a field emission device including a plurality of unit blocks composed of a plurality of cathode electrodes, a plurality of emitters and a fluorescent film as a backlight unit, each unit color can be sequentially emitted, and the luminance can be adjusted for each block. have. Accordingly, by applying a local dimming technique to the liquid crystal display, it is possible to improve contrast ratio and to improve moving image afterimage.

Description

Field emission device {FIELD EMISSION DEVICE}

The present invention relates to a field emission device, and more particularly, to a field emission device having a fast response speed that can be used as a backlight unit of a liquid crystal display device.

A liquid crystal display (LCD) displays an image by supplying a voltage to each pixel of a liquid crystal panel according to an input image signal and adjusting light transmittance of the pixels. It is mainly used for mobile communication terminal.

As a color implementation method of a liquid crystal display device, a spatial division method in which pixels having spatially divided unit colors (for example, red, green, and blue) are spatially mixed to realize various colors, and a unit color sequentially expressed There is a color sequential driving method or a field sequential color driving method that mixes this time to realize various colors.

Here, the color sequential driving method divides the entire frame on the liquid crystal panel into subframes of unit colors (for example, red, green, and blue), and the backlight unit includes monochromatic light sources of unit colors, respectively. As a result, when the unit colors are sequentially turned on within a short time, the unit colors are mixed in time, so that various colors can be realized without a color filter.

Conventionally, a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED) is mainly used as a backlight unit of a liquid crystal display.

However, since cold cathode fluorescent lamps use mercury gas, they cause environmental pollution, have a slow response time, low color reproducibility, and have disadvantages of being unsuitable for light and thin panels.

LED has the advantage of being environmentally friendly compared to cold cathode fluorescent lamps, but when using a large number of LEDs to increase the amount of light, there is a problem such as an increase in manufacturing cost, heat generation. In addition, although the response speed is faster than that of the cold cathode fluorescent lamp, there is a problem that color breaking occurs in the color sequential driving method because the speed is not fast enough.

On the other hand, in recent years, a local dimming technique for individually controlling the backlight unit has been proposed. Local dimming technology can selectively turn off the backlight unit for dark areas of the screen to reduce power consumption, improve contrast ratio, and improve image retention.

In order to apply such a local dimming technology to a liquid crystal display, hundreds of backlight units are required. When using an LED as a backlight unit, as described above, problems such as an increase in manufacturing cost and heat generation are caused.

The present invention has been proposed to solve the above problems, and an object thereof is to provide a field emission device for a backlight unit suitable for a color sequential local dimming liquid crystal display device.

In order to achieve the above object, the present invention provides a field emission device, comprising: a plurality of cathode electrodes formed on an upper surface of a first substrate; An anode formed on a lower surface of a second substrate and disposed to face the cathode; A fluorescent film formed of alternating red, green, and blue patterns formed on the anode electrode, wherein the red, green, and blue patterns are arranged in an oblique direction; And a plurality of emitters formed on the plurality of cathode electrodes to correspond to the red, green, and blue patterns.

According to the present invention, by using the electroluminescent device having a fast response speed as a backlight unit, it is possible to prevent the color breaking phenomenon in the color sequential driving method.

In addition, according to the present invention, by using a field emission device including a plurality of unit blocks consisting of a plurality of cathode electrodes, a plurality of emitters and a fluorescent film as a backlight unit, each unit color can be sequentially emitted, each block You can adjust the brightness separately. Accordingly, by applying a local dimming technique to the liquid crystal display, it is possible to improve contrast ratio and to improve moving image afterimage.

In particular, by arranging the red, green and blue patterns included in the fluorescent film alternately in an oblique direction, it is possible to solve the problem that a specific color is not mixed at the edge of the block.

1 is a view showing the configuration of a field emission device according to an embodiment of the present invention
2 is a view showing a fluorescent film according to an embodiment of the present invention
3 is a diagram illustrating a configuration of a unit block of an electroluminescent device according to an embodiment of the present invention.
4 is a view showing a cathode electrode array of a field emission device according to an embodiment of the present invention, in particular, a case in which a plurality of unit blocks are arranged
5 is a view showing the configuration of a field emission device according to an embodiment of the present invention, in particular, a case including a data electrode
FIG. 6 is a diagram illustrating a configuration of a unit block of an electroluminescent device according to an embodiment of the present invention. In particular, FIG. 6 illustrates a configuration of an electroluminescent device having data electrodes for controlling a plurality of unit blocks, respectively.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the technical idea of the present invention.

1 is a view showing the configuration of a field emission device according to an embodiment of the present invention.

As shown, the field emission device 100 according to an embodiment of the present invention is a plurality of cathode electrodes (120A, 120B, 120C) formed on the upper surface of the first substrate 110, the second substrate 150 An anode electrode 160 formed on the bottom surface and disposed to face the cathode electrodes 120A, 120B, and 120C; Comprising a red, green and blue pattern formed alternately on the anode electrode 160, the fluorescent film 170A, 170B, 170C and the red, green and blue pattern in which the red, green and blue patterns are arranged diagonally It includes a plurality of emitters (130A, 130B, 130C) formed on the plurality of cathode electrodes (120A, 120B, 120C) to correspond to.

In addition, the field emission device 100 is positioned between the plurality of cathode electrodes 120A, 120B, and 120C and the anode electrode 160 and has an opening at a position corresponding to the plurality of emitters 130A, 130B, and 130C. The gate electrode 140 may further include a diffusion plate 180 formed on the second substrate 150 to mix red light, green light, and blue light emitted from the fluorescent films 170A, 170B, and 170C.

In addition, the field emission device 100 includes an anode power supply 190A for supplying a high voltage DC voltage to the anode electrode 160 and a gate power supply part for supplying a DC voltage of high voltage to the gate electrodes 120A, 120B, and 120C ( Preferably 190B).

The plurality of cathode electrodes 120A, 120B, and 120C are separated from each other at predetermined intervals to be electrically separated from each other. In particular, the plurality of cathode electrodes 120A, 120B, and 120C are formed to correspond to the respective fluorescent patterns of the fluorescent films 170A, 170B, and 170C.

The plurality of emitters 130A, 130B, and 130C are for emitting electrons and protrude from the surfaces of the cathode electrodes 120A, 120B, and 120C. The emitters 130A, 130B, and 130C emit electrons when the voltage difference between the cathode electrodes 120A, 120B, and 120C and the gate electrode 140 has a value greater than the threshold voltage.

Gate electrode 140 is for inducing field emission from a plurality of emitters 130A, 130B, 130C. It is formed on the plurality of cathode electrodes 120A, 120B, and 120C, and an insulating film, a spacer (not shown), and the like are interposed between the cathode electrodes 120A, 120B, and 120C and the gate electrode 140.

The current controllers 195A, 195B, and 195C are connected between the cathode electrodes 120A, 120B, and 120C and the ground voltage, and may be implemented by MOSFETs or the like. The current controllers 195A, 195B, and 195C are activated to connect the cathode electrodes 120A, 120B, and 120C to the ground electrode, or are deactivated to separate the cathode electrodes 120A, 120B, and 120C from the ground electrode, thereby providing a plurality of cathodes. The field emission currents flowing through the electrodes 120A, 120B, and 120C are respectively controlled.

The operation of the field emission device having the structure as described above is as follows.

When the current controllers 195A, 195B, and 195C are activated (ON), the cathode electrodes 120A, 120B, and 120C are grounded, and field emission occurs across the gate electrode 140 and the cathode electrodes 120A, 120B, and 120C. By applying a sufficient voltage, electrons are emitted from the plurality of emitters 130A, 130B, 130C.

The emitted electrons are accelerated by the DC voltage applied to the anode electrode 160 and collide with the red, green, and blue fluorescent patterns 170A, 170B, and 170C, thereby causing red, green, and blue light emission.

2 is a view showing a fluorescent film according to an embodiment of the present invention. However, for convenience of explanation, the shape of the fluorescent film is shown for only one single block, and the peripheral block is treated with a dotted line.

As shown in the drawing, the fluorescent films 170A, 170B, and 170C are formed of a plurality of fluorescent patterns representing unit colors. In the drawing, an example of three fluorescent patterns of red, green, and blue is shown. . In addition, in the drawing, as an example, a case in which red, green, and blue fluorescent patterns are alternately arranged, this is merely for convenience of description, and the fluorescent patterns may be arranged in various orders.

The fluorescent films 170A, 170B, and 170C are formed of alternately formed red patterns 170A, green patterns 170B, and blue patterns 170C. The red pattern 170A, the green pattern 170B, and the blue pattern 170C have a line shape extending in an oblique direction. That is, it has a diagonal arrangement rather than a horizontal or vertical arrangement.

If the red, green, and blue patterns are arranged horizontally or vertically, only one fluorescent pattern is arranged on the edge of the block, and thus, the white pattern is not mixed. On the other hand, when the red pattern 170A, the green pattern 170B and the blue pattern 170C are formed in the form of an oblique inclination at a predetermined inclination, all three unit colors are arranged at the edge of the block. The same problem can be solved.

3 is a diagram illustrating a configuration of a unit block of an electroluminescent device according to an embodiment of the present invention.

As shown, the electroluminescent device according to an embodiment of the present invention includes a plurality of cathode electrodes 120A, 120B and 120C, a plurality of emitters 170A, 170B and 170C, and a fluorescent film 170A, 170B and 170C. It includes a unit block consisting of, and comprises a plurality of such unit blocks.

Looking at the configuration of a single unit in more detail as follows.

The plurality of cathode electrodes 120A, 120B, and 120C are alternately arranged to correspond to the red pattern 170A, the green pattern 170B, and the blue pattern 170C arranged in the diagonal direction, respectively.

The first cathode electrode 120A is formed to have a finger type. Here, the finger type refers to a form consisting of a plurality of line portions extending in parallel in a predetermined direction and a connecting portion connecting one end of the plurality of line portions. In the present invention, since the first cathode electrode 120A of the finger type is arranged in an oblique direction, the line portion is arranged in a diagonal direction having a predetermined angle. In addition, the connection part is formed in a 'b' or 'b' shape along the edge of the unit block.

The second cathode electrode 120C has a finger type and is alternately arranged with the first cathode electrode 120A. That is, the second cathode electrode 120C and the first cathode electrode 120A are arranged to be symmetrical with each other, and line portions of each electrode are arranged to be alternately arranged.

The third cathode electrode 120B is formed to have a line type and is arranged between the first cathode electrode 120A and the second cathode electrode 120C. That is, since the third cathode electrode 120B is formed between the line portions of the first cathode electrode 120A and the second cathode electrode 120C, the third cathode electrode 120B has a zigzag line shape.

That is, the first cathode electrode 120A is arranged to correspond to the red pattern 170A, the second cathode electrode 120C is arranged to correspond to the blue pattern 170C, and the third cathode electrode 120B is the green pattern. It is arranged to correspond to 170B.

The plurality of emitters 130A, 130B or 130C formed on the same cathode electrode 120A, 120B or 120C are electrically connected to each other. In addition, the plurality of emitters 130A, 130B or 130C formed on the same cathode electrode 120A, 120B or 120C correspond to the same fluorescent pattern 170A, 170B or 170C.

The gate electrode 140 has a plurality of openings 1 corresponding to the plurality of emitters 130A, 130B, and 130C, respectively.

Accordingly, electrons emitted from the plurality of emitters 130A, 130B or 130C formed on the same cathode electrode 120A, 120B or 120C collide with the same fluorescent pattern 170A, 170B or 170C to cause light emission of the same color. do.

4 is a diagram illustrating a cathode electrode arrangement of a field emission device according to an embodiment of the present invention. In particular, FIG. 4 illustrates a case where a plurality of unit blocks are arranged.

As shown, the field emission device according to an embodiment of the present invention is arranged in a first direction (I-I ') and a second direction (II-II') intersecting the first direction (I-I '). It is provided with a plurality of unit blocks.

Accordingly, by using the field emission device including the plurality of unit blocks as the backlight unit, each unit color may be sequentially emitted, and the luminance may be adjusted for each block. That is, by applying local dimming technology to the liquid crystal display, the contrast ratio may be improved and the afterimage phenomenon may be improved.

FIG. 5 is a diagram illustrating a configuration of a field emission device according to an embodiment of the present invention, and particularly illustrates a case of including a data electrode.

As described above with reference to FIG. 4, when the field emission device includes a plurality of unit blocks, an externally connected terminal is required to control each of the plurality of unit blocks. A case where a plurality of data electrodes are formed will be described. However, since the other configuration is the same as described above, a description thereof will be omitted.

As shown, the field emission device 100 ′ according to an embodiment of the present invention is interposed between the first substrate 110 and the cathode electrodes 120A, 120B, and 120C, and the plurality of cathode electrodes 120A and 120B. And 120C) and a plurality of data electrodes 111 respectively connected.

Here, an interlayer insulating film 112 is provided between the cathode electrodes 120A, 120B, and 120C and the plurality of data electrodes 111, and an opening (②) exposing the data electrode 111 to a part of the interlayer insulating film 112. Is provided.

In addition, one cathode electrode 120A of the plurality of cathode electrodes 120A, 120B, and 120C is connected to one data electrode 111A of the plurality of data electrodes 111 through the opening ②. Accordingly, the plurality of cathode electrodes 120A, 120B, and 120C may be individually controlled through the plurality of data electrodes 111.

As described above, the plurality of cathode electrodes 120A, 120B, and 120C are spaced apart at predetermined intervals ③ and are insulated from each other.

FIG. 6 is a diagram illustrating a configuration of a unit block of an electroluminescent device according to an embodiment of the present invention. In particular, FIG. 6 illustrates a configuration of an electroluminescent device having data electrodes for controlling a plurality of unit blocks, respectively.

As shown, the electroluminescent device according to an embodiment of the present invention includes a plurality of data electrodes 111, a plurality of cathode electrodes 120A, 120B, 120C, a plurality of emitters 170A, 170B, 170C, and fluorescent light. And a unit block composed of the membranes 170A, 170B, and 170C, and a plurality of such unit blocks are provided.

The plurality of data electrodes 111A, 111B, and 111C are interposed between the first substrate 111 and the cathode electrodes 120A, 120B, and 120C, and are insulated by the interlayer insulating film 112, but are separated through the openings ②. It is connected to the cathode electrodes 120A, 120B, and 120C, respectively. Therefore, the plurality of cathode electrodes 120A, 120B, and 120C can be controlled using the plurality of data electrodes 111A, 111B, and 111C, respectively.

Here, the plurality of data electrodes 111A, 111B, and 111C are preferably in the form of lines extending in parallel in a predetermined direction, and are insulated from each other at predetermined intervals.

Other configurations are the same as described above, and thus will be omitted.

It is to be noted that the technical spirit of the present invention has been specifically described in accordance with the above-described preferred embodiments, but it is to be understood that the above-described embodiments are intended to be illustrative and not restrictive. In addition, it will be understood by those of ordinary skill in the art that various embodiments are possible within the scope of the technical idea of the present invention.

100, 100 ': field emission device 110: first substrate
120A, 120B, 120C: cathode electrodes 130A, 130B, 130C: emitter
140: gate electrode 150: second substrate
160: anode electrodes 170A, 170B, 170C: fluorescent film
180: diffuser 190A: anode power supply
190B: gate power supply unit 195A, 195B, 195C: current control unit
111: data electrode 112: interlayer insulating film

Claims

A plurality of cathode electrodes formed on an upper surface of the first substrate;
An anode formed on a lower surface of a second substrate and disposed to face the cathode;
A fluorescent film formed of alternating red, green, and blue patterns formed on the anode electrode, wherein the red, green, and blue patterns are arranged in an oblique direction; And
A plurality of emitters formed on the plurality of cathode electrodes to correspond to the red, green and blue patterns
Lt; / RTI >
And the plurality of cathode electrodes are alternately arranged to correspond to each of the red, green, and blue patterns arranged in the diagonal direction.

The method of claim 1,
A plurality of unit blocks consisting of the plurality of cathode electrodes, the plurality of emitters and the fluorescent film is included
Field emission device.

The method of claim 1,
The field emission device is a backlight unit of a liquid crystal display device.
Field emission device.

The method of claim 1,
A gate electrode positioned between the plurality of cathode electrodes and the anode electrode and having an opening at a position corresponding to the plurality of emitters
A field emission device further comprising.

The method of claim 1,
A plurality of data electrodes interposed between the first substrate and the cathode electrode and connected to the plurality of cathode electrodes, respectively;
A field emission device further comprising.

The method of claim 1,
A plurality of current controllers for controlling the field emission current flowing through the plurality of cathode electrodes, respectively
A field emission device further comprising.

The method of claim 1,
A diffusion plate formed on the second substrate to mix red light, green light, and blue light emitted from the fluorescent film;
Field emission device containing more.

delete

A plurality of cathode electrodes formed on an upper surface of the first substrate;
An anode formed on a lower surface of a second substrate and disposed to face the cathode;
A fluorescent film formed of alternating red, green, and blue patterns formed on the anode electrode, wherein the red, green, and blue patterns are arranged in an oblique direction; And
A plurality of emitters formed on the plurality of cathode electrodes to correspond to the red, green and blue patterns
Lt; / RTI >
The plurality of cathode electrodes,
A first cathode electrode of a finger type arranged in an oblique direction to correspond to the fluorescent film;
A second cathode electrode of a finger type arranged alternately with the first cathode electrode; And
And a third cathode electrode of a line type arranged between the first cathode electrode and the second cathode electrode.
Field emission device.

10. The method of claim 9,
The first cathode electrode is arranged to correspond to the red pattern, the second cathode electrode is arranged to correspond to the blue pattern, and the third cathode electrode is arranged to correspond to the green pattern.
Field emission device.