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Current-driven active matrix display panel for improved pixel programming

A display panel and current technology, applied in the driving field, can solve the problems of not being suitable for driving large-size and/or fine display panels, and not being able to quickly address and drive data lines.

Inactive Publication Date: 2005-02-09
NEC ELECTRONICS CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0024] A disadvantage of the fourth method is that the procedure is not suitable for driving large and / or fine display panels
However, this method cannot quickly address the drive data lines

Method used

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  • Current-driven active matrix display panel for improved pixel programming
  • Current-driven active matrix display panel for improved pixel programming
  • Current-driven active matrix display panel for improved pixel programming

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0093] Such as Figure 8 As shown, the OLED display in the first embodiment is composed of a display panel 10 , a scan line driver 1 , and a data line driver 2 . The display panel 10 is composed of scan lines 3 and data lines 4 . The data line 4 is driven by the data line driver 2 , and the scan line 3 is driven by the scan line driver 1 .

[0094] The pixels are arranged in rows and columns at the intersections of the scan lines 3 and the data lines 4, and each pixel includes an OLED element and a pixel circuit. Figure 9 is a circuit diagram of each pixel, wherein the pixel circuit is represented by reference numeral 11 and the OLED element is represented by reference numeral 5 .

[0095] The pixel circuit 11 includes three driving legs, which output the current to the node N in parallel OUT It is connected with the power supply VDD for providing the power supply level; the driving legs are respectively composed of PMOS thin film transistors Tr1-Tr3. The PMOS transistors ...

no. 2 example

[0119] In the second embodiment, the pixel circuit is modified so that the switches SW2_1~SW2_3 are controlled in response to the scan signal n_4 from the scan line driver 1 transmitted through the scan line 3-4, instead of the scan signal used to control the switch SW0 n_0; the modified pixel circuit is denoted by reference numeral 11A. The structure of the pixel circuit 11A is capable of turning on and off the switches SW2_1 to SW2_3 without depending on the switch SW0.

[0120] Figure 14 is a timing chart showing an example of the operation of the pixel circuit 11A in the second embodiment. In this embodiment, the scan signals n_0˜n_4 are activated to turn on the switches SW0, SW1_1˜SW1_3 and SW2_1˜SW2_3 at the beginning of the line address period. This allows the capacitors Cs1-Cs3 to be programmed in response to the programming current Iin.

[0121] The main difference between the first and second embodiments is that the scan signal n_4 is deactivated before the scan ...

no. 3 example

[0125] In the third embodiment, such as Figure 15 As shown, the pixel circuits in the first and second embodiments are modified; the modified pixel circuits are indicated by reference numeral 11B. The main difference in the structure of the pixel circuit is that the pixel circuit 11B only includes one capacitor for programming the driving current Idrv1˜Idrv3.

[0126] More precisely, the pixel circuit 11B includes parallel connection of the power supply VDD and the current output node N OUT The coupled PMOS drive transistors Tr1-Tr3. The sources of the driving transistors Tr1~Tr3 are connected to the power supply VDD, and the drains are respectively connected to the current output node N through the switches SW1_1~SW1_3. OUT connected. The gates of the drive transistors Tr1 to Tr3 are connected in common to one pin of the capacitor Cs. The other pin of the capacitor Cs is connected to the power supply VDD.

[0127] The pixel circuit 11B further includes switches SW0_0 , ...

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PUM

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Abstract

A display device is comprised of a data line driver, a scan line driver, and a display panel. The display panel is composed of a plurality of drive legs disposed between a current output node and a first node having a fixed potential, each of the drive legs including a drive transistor having a source connected to the first node, a capacitor connected between a gate of the drive transistor and a second node having a fixed potential, a first switch connected between the current output node and a drain of the drive transistor, and a second switch connected between the gate and the drain of the drive transistor. The display panel further includes a data line, a third switch connected between the current output node and the data line, a current-driven element, a fourth switch connected between the current output node and the current-driven element.

Description

technical field [0001] The present invention relates generally to drive techniques for current driven light emitting elements, and more particularly to active matrix driving of current driven light emitting elements such as organic light emitting diodes (OLEDs). Background technique [0002] OLED displays have potential advantages over other display devices such as liquid crystal displays, including their thin form factor, light weight, wide viewing angles, and improved suitability for displaying moving pictures. This drives the development of OLED displays. [0003] A typical OLED display system as shown in FIG. 1 includes a display panel 100 , a scan line driver 101 , and a data line driver 102 . The display panel 100 is composed of scan lines 103 and data lines 104 . Each pixel includes an OLED element. These pixels are placed where the scan lines 103 and the data lines 104 cross each other. [0004] Although OLED elements can be voltage-driven or current-driven, it i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L51/50G09G3/20G09G3/30G09G3/32
CPCG09G2300/0852G09G2300/0861G09G3/325G09G2310/062
Inventor 藤仓克之安部胜美下田雅通
Owner NEC ELECTRONICS CORP