ORGANIC ELECTROLUMINESCENT DISPLAY PANEL AND METHOD FOR FABRICATING THE SAME

• US 20190221620A1
• Filed: 09/01/2017
• Published: 07/18/2019
• Est. Priority Date: 08/09/2017
• Status: Active Grant

• Current Assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd. (TCL Technology Group Corp.)
• Original Assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd. (TCL Technology Group Corp.)
• Inventors: LI, Songshan
• Granted Patent: US 10,546,903 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1259 Multistep manufacturing methods
• CPC Class Codes: H01L 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78675 with normal-type structure, e.g. with top gate
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/15 Hole transporting layers
• CPC Class Codes: H10K 50/16 Electron transporting layers
• CPC Class Codes: H10K 50/17 Carrier injection layers
• CPC Class Codes: H10K 50/171 Electron injection layers
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/82 Cathodes
• CPC Class Codes: H10K 50/826 Multilayers, e.g. opaque multilayers
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/856 comprising reflective means
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/1201 Manufacture or treatment
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/126 Shielding, e.g. light-blocking means over the TFTs
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass
• CPC Class Codes: H10K 71/13 : using printing techniques, e.g. ink-jet printing or screen printing

Abstract

The present invention discloses an organic electroluminescent display panel, including a substrate; a thin film transistor formed on the substrate; a bottom electrode formed on a drain of the thin film transistor; a light-blocking layer formed on the bottom electrode, the light-blocking layer has a first through hole that exposes the bottom electrode; a pixel define layer formed on the thin film transistor, the bottom electrode, and the light-blocking layer, the pixel define layer has a second through hole, the second through hole completely exposes the first through hole; an organic electroluminescent device formed on the bottom electrode, an edge of the organic electroluminescent device is formed on the light-blocking layer; and a top electrode formed on the organic electroluminescent device. The present invention uses the light-blocking layer to block the edge of the organic electroluminescent device, thereby eliminating the non-uniform brightness of the edge of the organic electroluminescent device.

Claims

1. An organic electroluminescent display panel comprising:

a substrate;

a thin film transistor formed on the substrate;

a bottom electrode formed on a drain of the thin film transistor;

a light-blocking layer formed on the bottom electrode, wherein the light-blocking layer has a first through hole that exposes the bottom electrode;

a pixel define layer formed on the thin film transistor, the bottom electrode, and the light-blocking layer, wherein the pixel define layer has a second through hole, a diameter of the second through hole is larger than a diameter of the first through hole, and the second through hole completely exposes the first through hole;

an organic electroluminescent device formed on the bottom electrode, and an edge of the organic electroluminescent device formed on the light-blocking layer; and

a top electrode formed on the organic electroluminescent device.

2. The organic electroluminescent display panel according to claim 1, wherein a central axis of the first through hole is aligned to a central axis of the second through hole.

3. The organic electroluminescent display panel according to claim 1, wherein the light-blocking layer comprises silicon-rich oxide or silicon-rich nitride, the light-blocking layer is insulated and opaque.

4. The organic electroluminescent display panel according to claim 1, wherein the pixel define layer comprises polymethylmethacrylate (PMMA) or polyimide (PI).

5. The organic electroluminescent display panel according to claim 1, wherein the thin film transistor further comprises:

a polysilicon layer formed on the substrate, and the polysilicon layer comprises a non-doped layer, a heavily-doped layer formed at two sides of the non-doped layer, and a lightly-doped layer formed between the non-doped layer and the heavily-doped layer,

a gate insulation layer formed on the polysilicon layer and the substrate;

a gate formed on the gate insulation layer and over the polysilicon layer;

an interlayer insulation layer formed on the gate and the gate insulation layer;

a third through hole and a fourth through hole respectively penetrating through the interlayer insulation layer and the gate insulation layer;

a source and a drain formed on the interlayer insulation layer, and contacting the heavily-doped layer via the first through hole and the second through hole;

a flat layer formed on the interlayer insulation layer, the source, and the drain; and

a fifth through hole penetrating through the flat layer to expose the drain.

6. The organic electroluminescent display panel according to claim 5, wherein the thin film transistor further comprises a buffer layer formed between the substrate and both of the polysilicon layer and the gate insulation layer.

7. The organic electroluminescent display panel according to claim 1, wherein the organic electroluminescent device further comprises a hole injection layer, a hole transporting layer, an organic emission layer, an electron transporting layer, and an electron injection layer formed from the bottom electrode to the top electrode.

8. The organic electroluminescent display panel according to claim 5, wherein the organic electroluminescent device further comprises a hole injection layer, a hole transporting layer, an organic emission layer, an electron transporting layer, and an electron injection layer formed from the bottom electrode to the top electrode.

9. The organic electroluminescent display panel according to claim 6, wherein the organic electroluminescent device further comprises a hole injection layer, a hole transporting layer, an organic emission layer, an electron transporting layer, and an electron injection layer formed from the bottom electrode to the top electrode.

10. The organic electroluminescent display panel according to claim 1, wherein the bottom electrode is transparent or semi-transparent, and the top electrode is opaque and light-reflecting.

11. A method for fabricating an organic electroluminescent display panel comprising:

providing a substrate;

forming a thin film transistor on the substrate;

forming a bottom electrode on a drain of the thin film transistor;

forming a light-blocking layer on the bottom electrode;

forming a first through hole in the light-blocking layer to expose the bottom electrode;

forming a pixel define layer on the thin film transistor, the bottom electrode, and the light-blocking layer;

forming a second through hole in the pixel define layer to completely expose the first through hole, wherein a diameter of the second through hole is larger than a diameter of the first through hole;

forming an organic electroluminescent device on the bottom electrode and the light-blocking layer, and forming an edge of the organic electroluminescent device on the light-blocking layer; and

forming a top electrode on the organic electroluminescent device.

12. The method for fabricating the organic electroluminescent display panel according to claim 11, wherein the step of forming the thin film transistor on the substrate further comprises:

forming a buffer layer on the substrate;

forming a polysilicon layer on the substrate, and the polysilicon layer comprises a non-doped layer, a heavily-doped layer formed at two sides of the non-doped layer, and a lightly-doped layer formed between the non-doped layer and the heavily-doped layer;

forming a gate insulation layer on the polysilicon layer and the substrate;

forming a gate on the gate insulation layer and over the polysilicon layer;

forming an interlayer insulation layer on the gate and the gate insulation layer;

forming a third through hole and a fourth through hole in the interlayer insulation layer to respectively penetrate through the interlayer insulation layer and the gate insulation layer;

forming a source on the interlayer insulation layer to fill the third through hole and contact the heavily-doped layer, and forming a drain on the interlayer insulation layer to fill the fourth through hole and contact the heavily-doped layer;

forming a flat layer on the interlayer insulation layer, the source, and the drain; and

forming a fifth through hole in the flat layer to expose the drain.