TW201327797A - Pixel structure of organic electroluminescent display device - Google Patents

Abstract

The present invention discloses a pixel structure of an organic electroluminescent display device, which includes a substrate, a thin film transistor and a pixel electrode, wherein the thin film transistor is disposed on the substrate, and has a gate, a source and a drain, and the thin film transistor further has a first opening, and the first opening is connected to the drain of the thin film transistor, the pixel electrode is connected to a second opening for the drain of the thin film transistor to electrically connect to the pixel electrode through the first opening and the second opening, wherein the second opening is stacked on the first opening, when overlooked, the second opening is located at the first opening edge, thereby reducing the circuit area of the thin film transistor to increase the aperture ratio of pixel structure.

Description

Pixel structure of organic electroluminescent display device

The present invention relates to a display device, and more particularly to a pixel structure of an organic electroluminescent display device.

An organic electroluminescent device, which may also be referred to as an organic light emitting diode (OLED) display, includes a plurality of pixels, each of which has an anode (hole injection electrode), a cathode (electron injection electrode) and an organic light-emitting layer disposed between the anode and the cathode, the light-emitting layer further comprising an electron transport layer (ETL) and a hole transport layer (HTL) and for enhancing light emission One of the effects is an electron injection layer (EIL) and a hole injection layer (HIL). When the electrons of the anode and the cathode are injected into the light-emitting layer, the electrons and the motor are recombined and paired in the light-emitting layer to emit light, and the electrons and the holes are annihilated in pairs while emitting light. Since the panel of the organic electroluminescent display itself has a self-emission component, there is no need to provide a backlight, so the organic electroluminescent display has lightness, high contrast, low power consumption and wide compared with the liquid crystal display. The characteristics of the viewing angle and the like, and because of the dot matrix type display of the panel of the organic electroluminescent display, the characteristics of the high resolution and the fast response time are such that the organic electroluminescent display is regarded as Flat panel display (FPD) for the next generation.
In addition, the general light-emitting layer is selected from the group consisting of organic molecular materials (small molecule material and polymer material depending on the molecular weight), so the panel of the organic electroluminescent display is more selected from thin and light. The flexible material allows the organic electroluminescent panel to be used in a wider range of applications. However, organic molecular materials have the problem of aging of materials, which causes the luminous efficiency of the luminescent layer to decrease. Therefore, the research and development of organic electroluminescent display devices generally focus on how to compensate the luminous efficiency of the luminescent layer to avoid the problem of aging of the material. Layer, thereby maintaining the luminous efficiency of the display and even improving the luminous efficiency. Thus, in order to improve the aging problem, a compensating circuit is developed which uses a plurality of thin film transistors to provide a compensation voltage or a compensation current to compensate for the effect of the luminescence efficiency degradation caused by the aging problem of the luminescent layer.
In addition, each pixel of the organic electroluminescent display adjusts the brightness of the pixels by controlling the magnitude of the current passing through the light-emitting layer, and in order to make the brightness uniformity of the organic electroluminescent display better, generally every pixel The compensation circuit will be set up, and the compensation circuit will additionally occupy the use area of a single pixel, which will seriously affect the aperture ratio of a single pixel.
Furthermore, no matter how the compensation circuit of the organic light-emitting display is designed, the arrangement of the thin-film transistor to the pixel electrode needs to pass through two openings, as shown in the first figure, the pixel structure of the conventional organic light-emitting diode display 10 The substrate has a substrate 12, a thin film transistor 14 and a pixel electrode 16. The thin film transistor 14 has a gate 142, a source 144 and a drain 146, and the drain 146 is connected via a first opening 148. To the first conductive layer 150, the first conductive layer 150 is connected to the pixel electrode 16 via a second opening 152. The layout of the conventional pixel structure needs to consider the position and other components of the second opening 152. The staggered and circuit traces are spaced apart so that the first opening 148 and the second opening 152 are disposed far apart, thereby causing an increase in the circuit area of the thin film transistor 14, resulting in an decrease in the aperture ratio of the pixel structure 10.
In view of the above, the present invention provides a pixel structure of an organic electroluminescence display device which improves the problem of a decrease in the aperture ratio of a pixel structure of a conventional organic electroluminescence display device.

SUMMARY OF THE INVENTION A primary object of the present invention is to provide a pixel structure of an organic electroluminescence display device which provides an increase in the aperture ratio of a pixel structure of an organic electroluminescence display device.
A secondary object of the present invention is to provide a pixel structure of an organic electroluminescence display device that provides a compensation circuit to reduce the use area.
The invention provides a pixel structure of an organic electroluminescence display device, comprising a substrate, a thin film transistor, a first insulating layer, a second insulating layer and a pixel electrode. The thin film transistor is disposed on the substrate, one gate of the thin film transistor is electrically connected to a gate line, one source of the thin film transistor is electrically connected to a data line, and the first insulating layer is disposed on the thin film transistor, first The insulating layer has a first opening, the first opening is connected to one of the drains of the thin film transistor, the second insulating layer is disposed on the first insulating layer, the second insulating layer has a second opening, and the second opening The pixel is disposed on the first opening and connected to the pixel electrode, and the pixel electrode is electrically connected to the second conductive layer through the first opening and the second opening. In this way, the compensation circuit of the organic electroluminescent display can occupy a smaller pixel area, and the aperture ratio of the pixel is increased, thereby providing a pixel structure having a smaller size, so that the pixel structure of the present invention can be produced. Higher resolution display.
In order to give the review board members a better understanding and understanding of the structural features and the efficacies of the present invention, please refer to the preferred embodiment diagrams and the detailed descriptions as follows:

Please refer to the second drawing, which is a cross-sectional view of an embodiment of the present invention. As shown, the pixel structure 20 of the organic electroluminescent display device of the present invention comprises a substrate 22, a thin film transistor 24 and a pixel electrode 26. In addition, the thin film transistor 24 further includes a first conductive layer 242, a gate dielectric layer 244, a plurality of second conductive layers 246, a semiconductor layer 247, a first insulating layer 248, a third conductive layer 250, and a The second insulating layer 252 is further divided into a source 246a and a drain 246b. The first insulating layer 248 further has a first opening 248a, and the second insulating layer 252 further has a second opening. Hole 252a.
The thin film transistor 24 is disposed on the substrate 22, and the first conductive layer 242 is sequentially disposed on the substrate 22 to form a gate 242a of the thin film transistor 24. The gate dielectric layer 244 is disposed on the substrate 22 and covers the first a conductive layer 242, the second conductive layer 246 is respectively disposed on the gate dielectric layer 244, and respectively forms a source 246a and a drain 246b, and the semiconductor layer 247 is disposed between the source 246a and the drain 246b, and Connecting the source 246a and the drain 246b, the first insulating layer 248 is disposed on the second conductive layer 246, the first opening 248a of the first insulating layer 248 is located on one side of the drain 246b, and the third conductive layer 250 is disposed. The first opening 248a is connected to the drain 246b, the second insulating layer 252 is disposed on the first insulating layer 248 and the third conductive layer 250, and the second opening 252a of the second insulating layer 252 is located on the third conductive layer. On the layer 250, the third conductive layer 250 is connected to the pixel electrode 26 via the second opening 252a, that is, the drain 246b of the thin film transistor 24 is electrically connected to the pixel electrode via the first opening 248a and the second opening 252a. 26, and the position of the first opening 248a is overlapped with the position of the second opening 252a. Preferably, the aperture of the first opening 248a of the embodiment is larger than the aperture of the second opening 252a.
The thin film transistor 24 of the present embodiment is exemplified by a bottom gate type thin film transistor, that is, a part of the first conductive layer 242 is used as a gate of the thin film transistor 24, and the semiconductor layer is controlled by the voltage of the gate. 247 forms a channel that in turn controls conduction or turn-off between source 246a and drain 246b. The source 246a of the thin film transistor 24 is connected to a data line (not shown), and is connected to the first opening 248a by the drain 246b, and the second opening 252a is located on the first opening 248a, and the second opening The position of the hole 252a is overlapped with the position of the first opening 248a, so the position of the third conductive layer 250 is also overlapped with the position of the first opening 248a and the second opening 252a, so that the third aspect of the present invention The conductive layer 250 does not need to be considered in consideration of the circuit trace layout of the panel, so the thin film transistor 24 of the present invention reduces the area of use thereof, thereby increasing the aperture ratio.
Please refer to the third drawing, which is a cross-sectional view of another embodiment of the present invention. The difference between the second figure and the third figure is that the first conductive layer 242 of the second figure is located under the semiconductor layer 247, and the first conductive layer 346 of the third figure is located on the semiconductor layer 342. As shown, the pixel structure 30 of the present invention comprises a substrate 32, a thin film transistor 34 and a pixel electrode 36. The thin film transistor 34 further includes a semiconductor layer 342, a gate dielectric layer 344, a first conductive layer 346, a plurality of second conductive layers 348, a first insulating layer 350, a third conductive layer 352, and a second The insulating layer 354, wherein the gate dielectric layer 344 has a first contact hole 344a and a second contact hole 344b, the first insulating layer 350 has a first opening 350a, and the second insulating layer 354 has a second opening. 354a. Preferably, the aperture of the first opening 350a of the embodiment is larger than the aperture of the second opening 354a.
The thin film transistor 34 is disposed on the substrate 32. The semiconductor layer 342 is disposed on the substrate 32. The gate dielectric layer 344 is disposed on the semiconductor layer 342 and covers the substrate 32. The first contact of the gate dielectric layer 344 is provided. The holes 344a and the second contact holes 344b are respectively located on the top two sides of the semiconductor layer 342, and the first conductive layer 346 is located on the gate dielectric layer 344 and corresponds to the semiconductor layer 342 to serve as the gate 346a of the thin film transistor 34. The second conductive layers 348 are respectively disposed on two sides of the first conductive layer 346, and are respectively connected to the semiconductor layer 342 via the first contact hole 344a and the second contact hole 344b to serve as the source 348a of the thin film transistor 34, respectively. The first insulating layer 350 is disposed on the first conductive layer 346 and the second conductive layer 348 and further covers the gate dielectric layer 344. The first opening 350a of the first insulating layer 350 is located at the drain On 348b. In addition, since the connection relationship of the third conductive layer 352 to the pixel electrode 36 is the same as that of the previous embodiment, it will not be described again.
The thin film transistor 34 of the present embodiment is exemplified by a back gate thin film transistor, that is, the present invention can also reduce the thin film transistor 34 by using an organic electroluminescent display device using a back gate thin film transistor. Use the area to increase the aperture ratio.
In summary, the present invention is a pixel structure of an organic electroluminescence display device, which is connected to a pixel electrode by a first opening and a second opening of a thin film transistor, thereby reducing the film. The circuit area used by the transistor increases the aperture ratio of the pixel and is applied to a small-sized panel of high resolution.
While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

10. . . Pixel structure

12. . . Substrate

14. . . Thin film transistor

142. . . Gate

144. . . Source

146. . . Bungee

148. . . First opening

150. . . First conductive layer

152. . . Second opening

16. . . Pixel electrode

20. . . Pixel structure

twenty two. . . Substrate

twenty four. . . Thin film transistor

242. . . First conductive layer

244. . . Gate dielectric layer

246. . . Second conductive layer

246a. . . Source

246b. . . Bungee

247. . . Semiconductor layer

248. . . First insulating layer

248a. . . First opening

250. . . Third conductive layer

252. . . Second insulating layer

252a. . . Second opening

26. . . Pixel electrode

30. . . Pixel structure

32. . . Substrate

34. . . Thin film transistor

342. . . Semiconductor layer

344. . . Gate dielectric layer

344a. . . First contact hole

344b. . . Second contact hole

346. . . First conductive layer

348. . . Second conductive layer

348a. . . Source

348b. . . Bungee

350. . . First insulating layer

350a. . . First opening

352. . . Third conductive layer

354. . . Second insulating layer

354a. . . Second opening

36. . . Pixel electrode

The first figure is a cross-sectional view of a conventional organic electroluminescent display device;
2 is a cross-sectional view showing an embodiment of the present invention; and a third view is a cross-sectional view showing another embodiment of the present invention.

20. . . Pixel structure

twenty two. . . Substrate

twenty four. . . Thin film transistor

242. . . First conductive layer

244. . . Gate dielectric layer

246. . . Second conductive layer

246a. . . Source

246b. . . Bungee

247. . . Semiconductor layer

248. . . First insulating layer

248a. . . First opening

250. . . Third conductive layer

252. . . Second insulating layer

252a. . . Second opening

26. . . Pixel electrode

Claims (4)

A pixel structure of an organic electroluminescence display device, comprising:
a substrate;
a thin film transistor, which is disposed on the substrate, a gate of the thin film transistor is electrically connected to a gate line, and one source of the thin film transistor is electrically connected to a data line;
a first insulating layer disposed on the thin film transistor and having a first opening, the first opening connecting one of the drains of the thin film transistor;
a second insulating layer disposed on the first insulating layer and having a second opening on the first opening; and a pixel electrode connected to the second opening a hole, the pixel electrode is electrically connected to the drain via the first opening and the second opening. The pixel structure as claimed in claim 1, wherein the thin film electrocrystallization system comprises:
a first conductive layer disposed on the substrate and forming the gate of the thin film transistor;
a gate dielectric layer disposed on the substrate and covering the first conductive layer;
a semiconductor layer disposed on the gate dielectric layer;
a plurality of second conductive layers disposed on the gate dielectric layer and on two sides of the semiconductor layer to form the source and the drain of the thin film transistor, the first insulating layer being disposed on the semiconductor layer And the second conductive layer, the first opening of the first insulating layer is connected to the drain; and a third conductive layer is disposed on the first insulating layer and passes through the first opening Connecting the drain, the second insulating layer is disposed on the third conductive layer and covering the first insulating layer, the second opening of the second insulating layer is located on the first opening and connected to the third conductive a layer, the third conductive layer is connected to the pixel electrode via the second opening. The pixel structure as claimed in claim 1, wherein the thin film electrocrystallization system comprises:
a semiconductor layer disposed on the substrate;
a gate dielectric layer disposed on the semiconductor layer, the gate dielectric layer having at least one first contact hole and at least one second contact hole, wherein the first contact hole and the second contact hole are located in the semiconductor Two sides of the top of the layer;
a first conductive layer disposed on the gate dielectric layer and forming the gate of the thin film transistor;
a plurality of second conductive layers disposed on the gate dielectric layer, the second conductive layers being disposed on two sides of the first conductive layer and separated from the first conductive layer, the second conductive layers respectively passing through the The first contact hole and the second contact hole are connected to the semiconductor layer to form the source and the drain, the first insulating layer is disposed on the first conductive layer and the second conductive layer, the first insulation The first opening of the layer is connected to the drain; and a third conductive layer is disposed on the first opening, and the drain is connected via the first opening, and the second insulating layer is disposed on the first opening The first conductive layer is disposed on the third conductive layer, the second opening of the second insulating layer is located on the first opening and connected to the third conductive layer, and the third conductive layer is connected through the second opening The pixel electrode. The pixel structure of claim 1, wherein the aperture of the first opening is larger than the aperture of the second opening.