Display device with improved drive arrangement

• US 7,675,232 B2
• Filed: 12/06/2006
• Issued: 03/09/2010
• Est. Priority Date: 11/29/2001
• Status: Expired due to Term

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Sato, Toshihiro, Kawachi, Genshiro, Tokuda, Naoki, Nishitani, Shigeyuki
• Primary Examiner(s): Roy; Sikha
• Application Number:
  US11/634,089
• Publication Number:
  US 20070080918A1
• Time in Patent Office: 1,189 Days
• Field of Search: 345 76- 80, 345/92
• US Class Current: 313/506
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 29/78645 with multiple gate
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/88 Dummy elements, i.e. elements having non-functional features

Abstract

A self-luminescence display device, in which dispersion in display among a plurality of pixels, caused by dispersion in characteristics among drive thin-film transistors, is decreased and uniform display free of unevenness can be obtained. The device includes a plurality of pixels having current drive type luminescent elements, and parallel-connected n (n≧2) thin-film transistors to feed a drive current to the respective current drive type luminescent elements. The transistors are arranged in different pixels, respectively, for example, in a first region of pixels adjacent to one another along a first direction. A second region of dummy pixels can be provided on at least one side of said first region along said first direction.

Claims

1. An EL display device comprising a plurality of EL pixels, each pixel being comprised of an anode electrode, an electroluminescent layer, a cathode electrode, a drive TFT, a scanning signal wiring, a picture signal wiring, and an anode current feeding wiring, wherein the anode electrode of one of the EL pixels is connected to the drive TFT of said one pixel formed under said one pixel, and to the drive TFT formed under another one of said pixels, each pixel further comprising a switch TFT including a gate electrode connected to the scanning signal wiring of the pixel, a source electrode connected to the picture signal wiring of the pixel, and a drain electrode connected to gate electrodes of the drive TFT of the pixel and to drive TFT of another pixel,

wherein a source electrode of the drive TFT of the one pixel is connected to the corresponding anode current feeding wiring which belongs to the one pixel, and a source electrode of the drive TFT of said another pixel is connected to the corresponding anode current feeding wiring which belongs to the another pixel.

2. The EL display device according to claim 1,

wherein both a drain electrode of the drive TFT of the one pixel and a drain electrode of the drive TFT of the another pixel are connected to the anode electrode of the said one pixel.

3. The EL display device according to claim 1, wherein the drive TFT of said one pixel and the drive TFT of said another pixel are arranged at different distances from a corresponding one of the scanning signal wirings in a plan view.

4. An EL display device comprising a first EL pixel and a second EL pixel,

wherein said first EL pixel and said second EL pixel are each comprised of an anode electrode, an electroluminescent layer, a cathode electrode, a drive TFT, a scanning signal wiring, a picture signal wiring, and an anode current feeding wiring,

wherein an anode electrode of the first EL pixel is connected and driven by a first drive TFT formed under the first EL pixel and by a second drive TFT formed under the second EL pixel, and

wherein a switch TFT of the first EL pixel includes a gate electrode connected to the scanning signal wiring, a source electrode connected to the picture signal wiring, and a drain electrode connected to a gate electrode of the first drive TFT and to a gate electrode of the second drive TFT,

wherein a source electrode of the drive TFT of the one pixel is connected to the corresponding anode current feeding wiring which belongs to the one pixel, and a source electrode of the drive TFT of said another pixel is connected to the corresponding anode current feeding wiring which belongs to the another pixel.

5. The EL display device according to claim 4, wherein both a drain electrode of the first drive TFT and a drain electrode of the second drive TFT are connected to the anode electrode of the first EL pixel.

6. The EL display device according to claim 5, wherein the first drive TFT and the second drive TFT are arranged at different distances from one of the scanning signal wirings in a plan view.

7. The EL display device according to claim 4, further comprising a third EL pixel and a third drive TFT, wherein the third drive TFT is arranged under the third EL pixel and a gate electrode of the third drive TFT is connected to the drain electrode of the switch TFT, a source electrode of the third drive TFT is connected to the anode current feeding wiring which belongs to the third EL pixel, and a drain electrode of the third drive TFT is connected to the another electrode of the first EL pixel.

8. The EL display device according to claim 7, wherein the first drive TFT, the second drive TFT and the third drive TFT are arranged at different distances from one of the scanning signal wirings in a plan view.