Semiconductor device

• US 20070176176A1
• Filed: 06/04/2003
• Published: 08/02/2007
• Est. Priority Date: 06/05/2002
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Osame, Mitsuaki, Fukumoto, Ryota, Hayakawa, Masahiko, Tanada, Yoshifumi, Anzai, Aya, Yamazaki, Shunpei
• Granted Patent: US 7,592,980 B2
• Time in Patent Office: Days
• US Class Current: 257/59
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2330/04 Display protection
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: H01L 27/0248 for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• 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 27/1222 with a particular composition, shape or crystalline structure of the active layer
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 29/78675 with normal-type structure, e.g. with top gate
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/1216 the pixel elements being capacitors
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals

Abstract

Semiconductor elements deteriorate or are destroyed due to electrostatic discharge damage. The present invention provides a semiconductor device in which a protecting means is formed in each pixel. The protecting means is provided with one or a plurality of elements selected from the group consisting of resistor elements, capacitor elements, and rectifying elements. Sudden changes in the electric potential of a source electrode or a drain electrode of a transistor due to electric charge that builds up in a pixel electrode is relieved by disposing the protecting means between the pixel electrode of the light-emitting element and the source electrode or the drain electrode of the transistor. Deterioration or destruction of the semiconductor element due to electrostatic discharge damage is thus prevented.

Claims

1. A semiconductor device comprising:

a plurality of pixels, each of the pixels comprising;

a light-emitting element;

a transistor; and

a protecting means disposed between the light-emitting element and the transistor,

wherein the protecting means comprises at least one element selected from the group consisting of a resistor element, a capacitor element, a rectifying element and a combination thereof.

2. A semiconductor device according to claim 1, wherein the rectifying element is one of a transistor of which a drain electrode and a gate electrode are connected and a diode.

3. A semiconductor device comprising:

a plurality of pixels, each of the pixels comprising;

a light-emitting element having a pixel electrode;

a transistor having a source electrode and a drain electrode; and

a protecting means disposed between the pixel electrode of the light-emitting element and one of the source electrode and the drain electrode of the transistor,

wherein the protecting means comprises a resistor element connected in series with the pixel electrode.

4. A semiconductor device comprising:

a plurality of pixels, each of the pixels comprising;

a light-emitting element having a pixel electrode;

a transistor having a source electrode and a drain electrode; and

a protecting means disposed between the pixel electrode of the light-emitting element and one of the source electrode and the drain electrode of the transistor,

wherein the protecting means comprises a capacitor element for at least one of accumulation or discharge of electric charge that builds up in the pixel electrode.

5. A semiconductor device comprising:

a plurality of pixels, each of the pixels comprising;

a light-emitting element having a pixel electrode;

a first transistor having a first source electrode and a first drain electrode;

a protecting means disposed between the pixel electrode of the light-emitting element and one of the source electrode and the drain electrode of the transistor; and

an electric power source line,

wherein the protecting means comprises a second transistor comprising;

a gate electrode;

a second drain electrode being connected to the gate electrode; and

a second source electrode being connected to the electric power source line, and

wherein an electric charge that builds up in the pixel electrode is discharged into the electric power source line.

6. A semiconductor device comprising:

a plurality of pixels, each of the pixels comprising;

a light-emitting element having a pixel electrode;

a transistor having a source electrode and a drain electrode; and

a protecting means disposed between the pixel electrode of the light-emitting element and one of the source electrode and the drain electrode of the transistor; and

an electric power source line,

wherein the protecting means comprises a diode comprising;

a first electrode being connected to the pixel electrode; and

a second electrode being connected to the electric power source line, and

wherein an electric charge that builds up in the pixel electrode is discharged into the electric power source.

7. A semiconductor device comprising:

a plurality of pixels, each of the pixels comprising;

a light-emitting element having a pixel electrode;

a transistor having a first source electrode and a first drain electrode; and

a protecting means disposed between the pixel electrode of the light-emitting element and one of the source electrode and the drain electrode of the transistor; and

an electric power source line,

wherein the protecting means comprises a transistor comprising;

a gate electrode;

a second drain electrode being connected to the gate electrode; and

a second source electrode being connected to the electric power source line,

wherein an electric charge that builds up in the pixel electrode is discharged into the electric power source line, and

wherein the electric potential of the pixel electrode is set to one of the electric potential of the electric power source line and an electric potential conforming thereto.

8. A semiconductor device comprising:

a plurality of pixels, each of the pixels comprising;

a light-emitting element having a pixel electrode;

a transistor having a source electrode and a drain electrode; and

a protecting means disposed between the pixel electrode of the light-emitting element and one of the source electrode and the drain electrode of the transistor; and

an electric power source line,

wherein the protecting means comprises a diode comprising;

a first electrode being connected to the pixel electrode; and

a second electrode being connected to the electric power source line,

wherein electric charge that builds up in the pixel electrode is discharged into the electric power source line, and

wherein the electric potential of the pixel electrode is set to one of the electric potential of the electric power source line and an electric potential conforming thereto.