Amoled display device and driving method thereof

• US 10,643,530 B2
• Filed: 11/20/2017
• Issued: 05/05/2020
• Est. Priority Date: 10/09/2017
• Status: Active Grant

• Current Assignee: Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
• Original Assignee: Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
• Inventors: Hwang, Taijiun, Wang, Zhenling
• Primary Examiner(s): Mishler, Robin J
• Application Number:
  US15/736,119
• Publication Number:
  US 20190385518A1
• Time in Patent Office: 897 Days
• CPC Class Codes: G09G 2300/0443 with several sub-pixels for the same colour in a pixel, not specifically used to display gradations G09G3/364 takes precedence
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2330/08 Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• 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 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/814 combined with auxiliary electrodes, e.g. ITO layer combined with metal lines
• CPC Class Codes: H10K 50/822 characterised by their shape
• CPC Class Codes: H10K 59/121 characterised by the geometry or disposition of pixel elements
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/1216 the pixel elements being capacitors
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/124 Insulating layers formed between TFT elements and OLED elements
• CPC Class Codes: H10K 59/80515 characterised by their shape

Abstract

An AMOLED display device and driving method thereof is provided. In the AMOLED display device, the anode layer on the pixel area comprises a first anode and a second anode formed around and separated from the first anode, the first sub OLED is composed of the first anode, the OLED functional layer and the cathode on the first anode, and the second sub OLED is composed of the second anode, the OLED functional layer and the cathode on the second anode; for each pixel area, a pixel driving circuit is formed correspondingly; the pixel driving circuit is coupled to the first and the second anode; when operated, the pixel driving circuit sends the first current and the second current different from the first current to the first anode and the second anode so that the luminance strength of the first sub OLED and the second sub OLED is the same.

Claims

1. An AMOLED display device, comprising:

a TFT substrate;

a plurality of pixel separating banks arranged on the TFT substrate, a plurality of OLED functional layers arranged on the TFT substrate; and

a cathode arranged on the OLED functional layers;

wherein, the pixel separating banks defines a plurality of pixel areas on the TFT substrate, and the OLED functional layers are formed on the pixel areas, respectively;

wherein, the TFT substrate comprises a substrate;

a TFT array layer formed on the substrate; and

a plurality of anode layers formed on the TFT array layer and correspondingly on the pixel areas;

wherein, each anode layer comprises;

a first anode formed on center of a corresponding one of the pixel areas; and

a second anode separated from and formed around the first anode;

wherein a first sub OLED is composed of the first anode and the OLED functional layer and the cathode on the first anode, and a second sub OLED is composed of the second anode and the OLED functional layer and the cathode on the second anode;

wherein, for each one of the pixel areas, a pixel driving circuit is formed correspondingly in the AMOLED display device;

the pixel driving circuit is electrically coupled to the first anode and the second anode, respectively; and

, when the AMOLED display device is operated, the pixel driving circuit is used to send a first current and a second current to the first anode and the second anode, respectively, to drive the first sub OLED and the second sub OLED to illuminate light to keep luminance strength of the first sub OLED and the second sub OLED to be the same;

wherein materials forming the pixel separating banks are hydrophilic, a thickness of the OLED functional layer corresponding to the first anode is smaller than the thickness of the OLED functional layer corresponding to the second anode; and

the first current is smaller than the second current.

2. The AMOLED display device as claimed in claim 1, wherein each pixel driving circuit comprises a first TFT, a second TFT, a third TFT, a fourth TFT, a first capacitor and a second capacitor;

wherein the first TFT, the second TFT, the third TFT, the fourth TFT, the first capacitor and the second capacitor are in the TFT array layer;

a gate of the first TFT is coupled to receive a scan signal, a source of the first TFT is coupled to receive a first data signal, and a drain of the first TFT is electrically coupled to a gate of the second TFT;

a drain of the second TFT is coupled to receive a positive power source, and a source of the second TFT is electrically coupled to the first anode in the corresponded pixel area;

a gate of the third TFT is electrically coupled to the gate of the first TFT, a source of the third TFT is coupled to receive a second data signal, and a drain of the third TFT is electrically coupled to a gate of the fourth TFT;

a drain of the fourth TFT is coupled to receive the positive power source, and a source of the fourth TFT is electrically coupled to the second anode in the corresponded pixel area;

two terminals of the first capacitor are electrically coupled to the gate and the drain of the second TFT, respectively; and

two terminals of the second capacitor are electrically coupled to the gate and the drain of the fourth TFT;

the cathode is coupled to receive a negative power source;

when the AMOLED display device is operated, the first TFT and the third TFT are turned on by the scan signal, and the first current and the second current are generated and are fed to the first anode and the second anode, respectively, in correspondence to inputting the first data signal and the second data signal to the gate of the second TFT and the gate of the fourth TFT, respectively.

3. The AMOLED display device as claimed in claim 1, wherein the TFT substrate further comprises a planarization layer formed between the anode layers and the TFT array layer.

4. The AMOLED display device as claimed in claim 3, wherein a thickness of an area of the planarization layer corresponding to the first anode is smaller than a thickness of an area of the planarization layer corresponding to the second anode.

5. A driving method of AMOLED display device, comprising:

step S1, providing an AMOLED display device;

wherein, the AMOLED display device comprises;

a TFT substrate;

a plurality of pixel separating banks arranged on the TFT substrate, a plurality of OLED functional layers arranged on the TFT substrate; and

a cathode arranged on the OLED functional layers;

wherein, the pixel separating banks defines a plurality of pixel areas on the TFT substrate, and the OLED functional layers are formed on the pixel areas, respectively;

wherein, the TFT substrate comprises a substrate;

a TFT array layer formed on the substrate; and

a plurality of anode layers formed on the TFT array layer and correspondingly on the pixel areas;

wherein, each anode layer comprises;

a first anode formed on center of a corresponding one of the pixel areas; and

a second anode separated from and formed around the first anode;

wherein a first sub OLED is composed of the first anode and the OLED functional layer and the cathode on the first anode, and a second sub OLED is composed of the second anode and the OLED functional layer and the cathode on the second anode;

wherein, for each one of the pixel areas, a pixel driving circuit is formed correspondingly in the AMOLED display device;

the pixel driving circuit is electrically coupled to the first anode and the second anode, respectively; and

step S2, displaying by the AMOLED display device, wherein the pixel driving circuit sends a first current and a second current to the first anode and the second anode, respectively, to drive the first sub OLED and the second sub OLED to illuminate light to keep luminance strength of the first sub OLED and the second sub OLED to be the same;

wherein materials forming the pixel separating banks are hydrophilic, a thickness of the OLED functional layer corresponding to the first anode is smaller than the thickness of the OLED functional layer corresponding to the second anode; and

the first current is smaller than the second current in the step S2.

6. The driving method as claimed in claim 5, wherein each pixel driving circuit comprises a first TFT, a second TFT, a third TFT, a fourth TFT, a first capacitor and a second capacitor;

wherein the first TFT, the second TFT, the third TFT, the fourth TFT, the first capacitor and the second capacitor are in the TFT array layer;

a gate of the first TFT is coupled to receive a scan signal, a source of the first TFT is coupled to receive a first data signal, and a drain of the first TFT is electrically coupled to a gate of the second TFT;

a drain of the second TFT is coupled to receive a positive power source, and a source of the second TFT is electrically coupled to the first anode in the corresponded pixel area;

a gate of the third TFT is electrically coupled to the gate of the first TFT, a source of the third TFT is coupled to receive a second data signal, and a drain of the third TFT is electrically coupled to a gate of the fourth TFT;

a drain of the fourth TFT is coupled to receive the positive power source, and a source of the fourth TFT is electrically coupled to the second anode in the corresponded pixel area;

two terminals of the first capacitor are electrically coupled to the gate and the drain of the second TFT, respectively; and

two terminals of the second capacitor are electrically coupled to the gate and the drain of the fourth TFT;

the cathode is coupled to receive a negative power source;

in the step S2, when the AMOLED display device is operated, the first TFT and the third TFT are turned on by the scan signal, and the first current and the second current are generated and are fed to the first anode and the second anode, respectively, in correspondence to inputting the first data signal and the second data signal to the gate of the second TFT and the gate of the fourth TFT, respectively.

7. An AMOLED display device, comprising:

a TFT substrate;

a plurality of pixel separating banks arranged on the TFT substrate, a plurality of OLED functional layers arranged on the TFT substrate; and

a cathode arranged on the OLED functional layers;

wherein, the pixel separating banks defines a plurality of pixel areas on the TFT substrate, and the OLED functional layers are formed on the pixel areas, respectively;

wherein, the TFT substrate comprises a substrate;

a TFT array layer formed on the substrate; and

a plurality of anode layers formed on the TFT array layer and correspondingly on the pixel areas;

wherein, each anode layer comprises;

a first anode formed on center of a corresponding one of the pixel areas; and

a second anode separated from and formed around the first anode;

wherein a first sub OLED is composed of the first anode and the OLED functional layer and the cathode on the first anode, and a second sub OLED is composed of the second anode and the OLED functional layer and the cathode on the second anode;

wherein, for each one of the pixel areas, a pixel driving circuit is formed correspondingly in the AMOLED display device;

the pixel driving circuit is electrically coupled to the first anode and the second anode, respectively; and

, when the AMOLED display device is operated, the pixel driving circuit is used to send a first current and a second current to the first anode and the second anode, respectively, to drive the first sub OLED and the second sub OLED to illuminate light to keep luminance strength of the first sub OLED and the second sub OLED to be the same;

wherein materials forming the pixel separating banks are hydrophilic, a thickness of the OLED functional layer corresponding to the first anode is smaller than the thickness of the OLED functional layer corresponding to the second anode; and

the first current is smaller than the second current;

wherein each pixel driving circuit comprises a first TFT, a second TFT, a third TFT, a fourth TFT, a first capacitor and a second capacitor;

wherein the first TFT, the second TFT, the third TFT, the fourth TFT, the first capacitor and the second capacitor are in the TFT array layer;

a gate of the first TFT is coupled to receive a scan signal, a source of the first TFT is coupled to receive a first data signal, and a drain of the first TFT is electrically coupled to a gate of the second TFT;

a drain of the second TFT is coupled to receive a positive power source, and a source of the second TFT is electrically coupled to the first anode in the corresponded pixel area;

a gate of the third TFT is electrically coupled to the gate of the first TFT, a source of the third TFT is coupled to receive a second data signal, and a drain of the third TFT is electrically coupled to a gate of the fourth TFT;

a drain of the fourth TFT is coupled to receive the positive power source, and a source of the fourth TFT is electrically coupled to the second anode in the corresponded pixel area;

two terminals of the first capacitor are electrically coupled to the gate and the drain of the second TFT, respectively; and

two terminals of the second capacitor are electrically coupled to the gate and the drain of the fourth TFT;

the cathode is coupled to receive a negative power source;

when the AMOLED display device is operated, the first TFT and the third TFT are turned on by the scan signal, and the first current and the second current are generated and are fed to the first anode and the second anode, respectively, in correspondence to inputting the first data signal and the second data signal to the gate of the second TFT and the gate of the fourth TFT, respectively;

wherein the TFT substrate further comprises a planarization layer formed between the anode layers and the TFT array layer;

wherein a thickness of an area of the planarization layer corresponding to the first anode is smaller than a thickness of an area of the planarization layer corresponding to the second anode.