ACTIVE MATRIX DEVICE, METHOD FOR MANUFACTURING SWITCHING ELEMENT, ELECTRO-OPTICAL DISPLAY DEVICE, AND ELECTRONIC APPARATUS

• US 20090120771A1
• Filed: 11/07/2008
• Published: 05/14/2009
• Est. Priority Date: 11/09/2007
• Status: Active Grant

• Current Assignee: 138 East LCD Advancements Limited (Vector Capital Corporation)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: NAMOSE, Isamu
• Granted Patent: US 8,223,285 B2
• Time in Patent Office: Days
• US Class Current: 200/175
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/40 Arrangements for improving the aperture ratio
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

An active matrix device includes: a substrate; a pixel electrode formed at a side adjacent to one of surfaces of the substrate; a switching element, including: a fixed electrode formed so as to correspond to the pixel electrode and coupled with the pixel electrode; a movable electrode formed so as to be displaced toward the fixed electrode along a surface direction of the substrate to be in one of states being in contact with the fixed electrode and apart from the fixed electrode; a driving electrode formed so as to form an electrostatic gap between the movable electrode and the driving electrode, the fixed electrode, the movable electrode, and the driving electrode being disposed in different positions from each other along the surface direction of the substrate; a first wiring line coupled with the movable electrode; and a second wiring line coupled with the driving electrode. The switching element generates an electrostatic attraction between the movable electrode and the driving electrode by applying a voltage between the movable electrode and the driving electrode so as to displace the movable electrode to be in contact with the fixed electrode for obtaining electrical conduction between the first wiring line and the pixel electrode.

Claims

1. An active matrix device, comprising:

a substrate;

a pixel electrode formed at a side adjacent to one of surfaces of the substrate;

a switching element, including;

a fixed electrode formed so as to correspond to the pixel electrode and coupled with the pixel electrode;

a movable electrode formed so as to be displaced toward the fixed electrode along a surface direction of the substrate to be in one of states being in contact with the fixed electrode and apart from the fixed electrode;

a driving electrode formed so as to form an electrostatic gap between the movable electrode and the driving electrode, the fixed electrode, the movable electrode, and the driving electrode being disposed in different positions from each other along the surface direction of the substrate;

a first wiring line coupled with the movable electrode; and

a second wiring line coupled with the driving electrode, wherein the switching element generates an electrostatic attraction between the movable electrode and the driving electrode by applying a voltage between the movable electrode and the driving electrode so as to displace the movable electrode to be in contact with the fixed electrode for obtaining electrical conduction between the first wiring line and the pixel electrode.

2. The active matrix device according to claim 1, wherein the fixed electrode, the movable electrode, and the driving electrode are formed in a sheet-like shape and disposed so that each surface of the fixed electrode, the movable electrode, and the driving electrode is nearly orthogonal to the surface of the substrate.

3. The active matrix device according to claim 1, wherein the fixed electrode, the movable electrode, and the driving electrode are form to extend in a direction parallel to one of the first wiring line and the second wiring line.

4. The active matrix device according to claim 1, wherein the movable electrode 5 is cantilever-supported so that a free end is displaced, and the fixed electrode is disposed so as to face an end portion of the movable electrode at a side adjacent to the free end, while the driving electrode is disposed so as to face a portion of the movable electrode closer to a side adjacent to a fixed end of the movable electrode than a position of the fixed electrode.

5. The active matrix device according to claim 1, wherein the fixed electrode, the movable electrode, and the driving electrode are arranged so that the movable electrode contacts the fixed electrode while the movable electrode and the driving electrode are apart from each other.

6. The active matrix device according to claim 5, wherein at least one of surfaces of the movable electrode and the fixed electrode that are facing to each other has a protrusion to prevent a contact of the movable electrode with the driving electrode.

7. The active matrix device according to claim 1, wherein the switching element further includes a housing portion having an air-tight space and accommodating the movable electrode, the driving electrode, and the fixed electrode therein.

8. The active matrix device according to claim 1, wherein the pixel electrode is formed in a different position from a position of the switching element in a thickness direction of the substrate so as to cover and include the switching element corresponding to the pixel electrode in plan view.

9. The active matrix device according to claim 1, wherein the first wiring line is formed in a plural number so as to be parallel to each other along the substrate, while the second wiring line is formed in a plural number so as to be parallel to each other along the substrate and intersect with the first wiring lines, and the switching element is formed in a vicinity of each of intersections of the first wiring lines and the second wiring lines.

10. A method for manufacturing the switching element included in the active matrix device according to claim 1, comprising:

forming a step portion having a wall surface formed on one of the surfaces of the substrate, the wall surface being perpendicular to the surface of the substrate;

forming a first electrode on the wall surface;

forming an insulating layer having an insulating property so as to cover the first electrode;

forming a second electrode on the insulating layer so as to face the first electrode through the insulating layer; and

removing a part of the insulating layer so as to form an electrostatic gap between the first electrode and the second electrode and allow the second electrode to be displaced to be in one of states being in contact with the first electrode and apart from the first electrode, wherein the first electrode serves as the driving electrode while the second electrode serves as the movable electrode.

11. An electro-optical device, comprising the active matrix device according to claim 1.

12. An electronic apparatus comprising the electro-optical device according to claim 11.