Electroluminescence display device

• US 6,958,740 B1
• Filed: 09/29/2000
• Issued: 10/25/2005
• Est. Priority Date: 10/01/1999
• Status: Expired due to Term

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Nishikawa, Ryuji
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): NGUYEN, KIMNHUNG T
• Application Number:
  US09/676,234
• Time in Patent Office: 1,852 Days
• Field of Search: 345/76, 345/87, 313/483, 313491-492, 313/498, 257/347, 257/40, 257/72, 257/59, 315/169.3
• US Class Current: 345/76
• CPC Class Codes: H10K 50/865 comprising light absorbing layers, e.g. light-blocking layers
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/126 Shielding, e.g. light-blocking means over the TFTs
• CPC Class Codes: H10K 59/8792 comprising light absorbing layers, e.g. black layers

Abstract

An EL element and an interface between a channel and an impurity diffusion area of a thin film transistor provided in the vicinity of the EL element are spaced apart. A light shielding film is provided between the EL element and the interface. By providing such a space and/or the light shielding film, generation of a leak current, which would otherwise be caused by light emitted from the self-emissive EL element entering the TFT, is reliably prevented, thereby ensuring that emitted light is not brighter than a predetermined luminance.

Claims

1. An EL display device having a plurality of display pixels comprising:

an EL element having an emissive layer between first and second electrodes,

a thin film transistor having first and second conductive regions formed of a semiconductor film, one of said first and second conductive regions being connected to said EL element, wherein a light shielding film for shielding light emitted from said EL element is provided between said EL element and an interface between said one of conductive regions connected to said EL element and a channel of said thin film transistor, said light shielding film is conductive, and wherein said light shielding film is provided between said thin film transistor and said EL element disposed on said thin film transistor with an insulating film therebetween, and

a second light shielding film provided between a transparent substrate on which said thin film transistor is formed and said thin film transistor.

2. The EL display device according to claim 1, wherein

said second light shielding film has an opening only at a region located inner than an outer edge of an emissive region of said EL element.

3. The EL display device according to claim 2, wherein

said second light shielding film is connected to a power source for supplying power to said EL element.

4. An EL display device having a plurality of display pixels comprising:

an EL element having an emissive layer between first and second electrodes;

a first thin film transistor having a first conductive region formed of a semiconductor film and connected to a data line, a gate electrode connected to a gate line, and a second conductive region; and

a second thin film transistor having a third conductive region formed of a semiconductor film and connected to a power source line of said EL element, a second gate electrode connected to said second conductive region of said first thin film transistor, and a fourth conductive region connected to said EL element;

wherein

a light shielding film for shielding light emitted from said EL element is provided between said EL element and an interface between a channel and said fourth conductive region of said second thin film transistor.

5. The EL display device according to claim 4, wherein a light shielding film is further provided over the semiconductor film forming an active layer of said fist thin film transistor.

6. The EL display device according to claim 4, wherein

the first or second electrode of said second thin film transistor also functions as said light shielding film.

7. The EL display device according to claim 4, wherein

said light shielding film is electrically connected to said power source line or to a power source.

8. An EL display device having a plurality of display pixels comprising:

an EL element having an emissive layer between first and second electrodes;

a first thin film transistor having a first conductive region formed of a semiconductor film and connected to a data line, a gate electrode connected to a gate line, and a second conductive region; and

a second thin film transistor having a third conductive region formed of a semiconductor film and connected to a power source line of said EL element, a second gate electrode connected to said second conductive region of said first thin film transistor, and a fourth conductive region connected to said EL element;

wherein

a light shielding film for shielding light emitted from said EL element is provided over the semiconductor film forming an active layer of said first thin film transistor and located between said active layer and said EL element.

9. The EL display device according to claim 8, wherein

the first or second electrode of said first thin film transistor also functions as said light shielding film.

10. The EL display device according to claim 8, wherein

said light shielding film is electrically connected to said power source line or to a power source.