El display device and electronic device

• US 20040207331A1
• Filed: 05/19/2004
• Published: 10/21/2004
• Est. Priority Date: 06/23/1999
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Koyama, Jun
• Granted Patent: US 7,358,531 B2
• Time in Patent Office: Days
• US Class Current: 315/169.3
• CPC Class Codes: G09G 2300/026 Video wall, i.e. juxtaposition of a plurality of screens to create a display screen of bigger dimensions
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0885 Pixel comprising a non-linear two-terminal element alone in series with each display pixel element
• CPC Class Codes: G09G 2310/0221 with use of split matrices G09G3/3644 and G09G3/3666 take precedence
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• 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 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes
• CPC Class Codes: G09G 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1251 comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• CPC Class Codes: H01L 27/1255 : integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 27/156 : two-dimensional arrays
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H10K 59/1213 : the pixel elements being TFTs
• CPC Class Codes: H10K 59/123 : Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/126 : Shielding, e.g. light-blocking means over the TFTs
• CPC Class Codes: H10K 59/131 : Interconnections, e.g. wiring lines or terminals

Abstract

An EL display device capable of producing a vivid multi-gradation color display, and an electronic device having the EL display device. An electric current supplied to an EL element 110 is controlled by providing a resistor 109 between a current control TFT 108 and the EL element 110 formed in a pixel 104, the resistor 109 having a resistance higher than the on-resistance of the current control TFT 108. The gradation display is executed by a time-division drive system which controls the emission and non-emission of light of the EL element 110 by time, preventing the effect caused by a dispersion in the characteristics of the current control TFT 108.

Claims

1. An electronic device comprising:

a substrate;

a current control TFT provided over said substrate;

an EL element provided over said substrate;

a resistor comprising a semiconductor provided between said EL element and a drain of said current control TFT; and

a light-shielding film provided over said semiconductor of said resistor.

2. A device according to claim 1 wherein said resistor has a resistance of 1 kΩ

to 50 MΩ

.

3. A device according to claim 1 wherein said light-shielding film comprises the same material as a gate electrode of said current control TFT.

4. An EL display device comprising:

a substrate;

a current control TFT provided over said substrate;

an EL element provided over said substrate;

a resistor comprising a semiconductor provided between said EL element and a drain of said current control TFT; and

a light-shielding film provided over said semiconductor of said resistor.

5. A device according to claim 4 wherein said resistor has a resistance of 1 kΩ

to 50 MΩ

.

6. A device according to claim 4 wherein said light-shielding film comprises the same material as a gate electrode of said current control TFT.

7. A personal computer comprising:

a substrate;

a current control TFT provided over said substrate;

an EL element provided over said substrate;

a resistor comprising a semiconductor provided between said EL element and a drain of said current control TFT; and

a light-shielding film provided over said semiconductor of said resistor.

8. A personal computer according to claim 7 wherein said resistor has a resistance of 1 kΩ

to 50 MΩ

.

9. A personal computer according to claim 7 wherein said light-shielding film comprises the same material as a gate electrode of said current control TFT.

10. A video camera comprising:

a substrate;

a current control TFT provided over said substrate;

an EL element provided over said substrate;

a resistor comprising a semiconductor provided between said EL element and a drain of said current control TFT; and

a light-shielding film provided over said semiconductor of said resistor.

11. A video camera according to claim 10 wherein said resistor has a resistance of 1 kΩ

to 50 MΩ

.

12. A video camera according to claim 10 wherein said light-shielding film comprises the same material as a gate electrode of said current control TFT.

13. A head-mounted display comprising:

a substrate;

a current control TFT provided over said substrate;

an EL element provided over said substrate;

a resistor comprising a semiconductor provided between said EL element and a drain of said current control TFT; and

a light-shielding film provided over said semiconductor of said resistor.

14. A head-mounted display according to claim 13 wherein said resistor has a resistance of 1 kΩ

to 50 MΩ

.

15. A head-mounted display according to claim 13 wherein said light-shielding film comprises the same material as a gate electrode of said current control TFT.

16. A picture reproducing apparatus comprising:

a substrate;

a current control TFT provided over said substrate;

an EL element provided over said substrate;

a resistor comprising a semiconductor provided between said EL element and a drain of said current control TFT; and

a light-shielding film provided over said semiconductor of said resistor.

17. A picture reproducing apparatus according to claim 16 wherein said resistor has a resistance of 1 kΩ

to 50 MΩ

.

18. A picture reproducing apparatus according to claim 16 wherein said light-shielding film comprises the same material as a gate electrode of said current control TFT.

19. A mobile computer comprising:

a substrate;

a current control TFT provided over said substrate;

an EL element provided over said substrate;

a resistor comprising a semiconductor provided between said EL element and a drain of said current control TFT; and

a light-shielding film provided over said semiconductor of said resistor.

20. A mobile computer according to claim 19 wherein said resistor has a resistance of 1 kΩ

to 50 MΩ

.

21. A mobile computer according to claim 19 wherein said light-shielding film comprises the same material as a gate electrode of said current control TFT.