Oscillation gyro equipped with thin PZT film

• US 6,378,368 B1
• Filed: 08/18/1999
• Issued: 04/30/2002
• Est. Priority Date: 10/09/1997
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Original Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Inventors: Iwata, Hitoshi, Itoigawa, Koichi
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US09/367,894
• Time in Patent Office: 986 Days
• Field of Search: 735/041.2, 735/041.3, 735/041.4, 735/041.5, 735/040.4, 735/040.3, 735/040.2, 310/311, 310/321, 310/329, 310/331
• US Class Current: 73/504.14
• CPC Class Codes: G01C 19/5642 using vibrating bars or beams

Abstract

An oscillation gyro (1) including a stainless steel base member (4) which is a quadratic prism, wherein the base member (4) has through holes (10, 7) extending in the directions crossing at right angles at the upper and lower portions thereof respectively, and further includes slide plates (8, 9) constituting a parallel plate portion (2) and slide plates (10, 11) constituting a parallel plate portion (3). Preferably, a titanium film (13) is formed by sputtering on each of the outer side surfaces of the parallel plate portions (2, 3), and a thin PZT film (14) is formed on the entire outer surface of the titanium film (13). Pairs of electrode films (15, 16) of aluminum are formed on the respective thin PZT films (14) up and down. The respective electrode films (15, 16) have a thickness of several um and the same area. Pads (15b, 16b) are formed at the lower ends of the base member (4) serving as fixed ends, and are connected to extension portions (15a, 16a) extending from the electrode film (15). Lead wires (19) connected to the pads (15a, 16a) suppress a change in the rigidity of the parallel plate portions (2, 3) caused by the connection of lead wires.

Claims

1. An oscillation gyroscope comprising:

a substrate (4) made of an elastic metal and having a substantially rectangular shape;

the substrate (4) having first to fourth side surfaces arranged in a circumferential direction, wherein the first side surface (5) and the third side surface, and the second side surface (6) and the fourth side surface are located on opposite sides;

the substrate (4) having a fixed end for fixing the oscillation gyroscope, and a free end located on an opposite side of the fixed end;

the substrate (4) having a first opening (7) extending from the first side surface (5) to the third side surface at the fixed end;

a first parallel plate portion (2) located on both sides of the first opening (7) and having a pair of side plates (8, 9) including the second and fourth side surfaces;

the substrate (4) having a second opening (10) extending from the second side surface (6) to the fourth side surface at the free end;

a second parallel plate portion (3) located on both sides of the second opening (10) and having a pair of side plates (11, 12) including the first and third side surfaces;

a titanium base surface (13) formed respectively on the second and fourth side surfaces of the first parallel plate portion and the first and third side surfaces of the second parallel plate portion (3);

a PZT thin film (14) formed on each base surface (13);

an electrode (15, 16) formed on each PZT thin film (14); and

a connecting pad (15b, 16b) electrically connected to any one of the electrodes (15, 16) of the PZT thin films (14).

2. The oscillation gyroscope according to claim 1 characterized by further comprising bridges (15a, 16a) connecting the electrodes (15, 16) to the associated pads (15b, 16b).

3. The oscillation gyroscope according to claim 2 characterized in that the bridges (16a) extend along the edges of the first and third side surfaces to connect the electrodes (16), which correspond to the second parallel plate portion (3), to the pads (16b) of the fixed end portion.

4. The oscillation gyroscope according to claim 2 characterized in that the bridges (15a) extend along the edges of the second and fourth side surfaces to connect the electrodes (15), which correspond to the first parallel plate portion (2), to the pads (15b) of the fixed end portion.

5. The oscillation gyroscope according to claim 2 characterized in that each side plate (8, 9, 11, 12) has a thin section and the bridges (15a, 16a) are formed on the thin sections.

6. The oscillation gyroscope according to claim 1 characterized in that each opening (7, 10) has a substantially rectangular cross-section.

7. The oscillation gyroscope according to claim 1 characterized in that each electrode (15, 16) and the associated pad (15b, 16b) are arranged on the same side surface of the substrate (4).

8. The oscillation gyroscope according to claim 1 characterized by further comprising another electrode (15, 16) formed on each PZT thin film (14) and another pad (15b, 16b) formed on the fixed end portion, wherein the two electrodes (15, 16) on each PZT thin film (14) are paired and have substantially the same area.

9. The oscillation gyroscope according to claim 1 characterized in that the substrate (4) further includes connecting portions for connecting the paired side plates (8, 9, 11, 12).