Active matrix organic light emitting diode display panel circuit

• US 6,970,149 B2
• Filed: 12/31/2002
• Issued: 11/29/2005
• Est. Priority Date: 09/14/2002
• Status: Active Grant

• Current Assignee: Uniloc 2017 LLC (SoftBank Group Corp.)
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Hwang, Chi-Sun, Chung, Choong-Heui, Lee, Jin-ho, Song, Yoon-Ho
• Primary Examiner(s): LAO, LUN YI
• Application Number:
  US10/334,837
• Publication Number:
  US 20040051685A1
• Time in Patent Office: 1,064 Days
• Field of Search: 345 76- 83, 345/204, 315/169.1, 315/169.2, 315/169.3
• US Class Current: 345/82
• CPC Class Codes: G09G 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

An active matrix organic light emitting diode display panel circuit capable of reducing current and brightness nonuniformities between pixels by including a threshold voltage compensation circuit block between a data line and the pixels is provided. The threshold voltage of a video signal loaded in a data line is compensated for while the video signal passes through the threshold voltage compensation circuit block and then provided to a driving transistor of the pixels. One threshold voltage compensation circuit block is connected commonly to a plurality of pixels, rather than be connected to every pixel, so that threshold voltage compensation can be achieved for high-quality, large-sized displays, without increasing the number of transistors for the pixels.

Claims

1. An active drive organic light emitting diode display panel circuit having a plurality of pixels, each of which includes an addressing transistor, a storage capacitor, an organic light emitting diode, and a driving transistor connected in series to the organic light emitting diode, the active drive organic light emitting diode display panel circuit comprising a threshold voltage compensation circuit block outside the pixels so that a video signal loaded in a data line is transmitted to the pixels via the threshold voltage compensation circuit block,

wherein the threshold voltage compensation circuit block comprises at least two thin film transistors connected in parallel.

2. The active drive organic light emitting diode display panel circuit of claim 1, wherein at least two threshold voltage compensation circuit blocks are connected in parallel to the data line.

3. The active drive organic light emitting diode display panel circuit of claim 1, wherein at least one of the thin film transistors has the same conductivity type as the driving transistor.

4. The active drive organic light emitting diode display panel circuit of claim 1, wherein when the at least two thin film transistors have different conductivity types, the at least two thin film transistors are connected in parallel with a common gate.

5. An active drive organic light emitting diode display panel circuit having a plurality of pixels, each of which includes an addressing transistor, a storage capacitor, an organic light emitting diode, and a driving transistor connected in series to the organic light emitting diode, the active drive organic light emitting diode display panel circuit comprising a threshold voltage compensation circuit block outside the pixels which is common to at least two pixels so that a video signal loaded in a data line is transmitted to each of the pixels via the corresponding threshold voltage compensation circuit block,

wherein the threshold voltage compensation circuit block comprises at least two thin film transistors connected in parallel.

6. The active drive organic light emitting diode display panel circuit of claim 5, wherein at least two threshold voltage compensation circuit blocks are connected in parallel to the data line.

7. The active drive organic light emitting diode display panel circuit of claim 5, wherein the threshold voltage compensation circuit block is connected in parallel to the at least two pixels.

8. The active drive organic light emitting diode display panel circuit of claim 5, wherein at least one of the thin film transistors has the same conductivity type as the driving transistor.

9. The active drive organic light emitting diode display panel circuit of claim 5, wherein when the at least two thin film transistors have different conductivity types, the at least two thin film transistors are connected in parallel with a common gate.