MEMS gyroscope having mass vibrating vertically on substrate

• US 20030110858A1
• Filed: 11/14/2002
• Published: 06/19/2003
• Est. Priority Date: 12/14/2001
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Jun-o, Lee, Sang-woo
• Granted Patent: US 6,915,693 B2
• Time in Patent Office: Days
• US Class Current: 73/504.02
• CPC Class Codes: G01C 19/5762 the sensing mass being connected to a driving mass, e.g. driving frames

Abstract

X type MEMS gyroscope has a first mass vertically vibrating on a substrate and a second mass horizontally vibrating on the substrate. A driving electrode is disposed on the same surface with the first mass. When the first mass vertically vibrates, the second mass vibrates vertically together with the first mass. When angular velocity that is at a right angle to a movement direction of the first mass and the second mass is applied while the first mass is vertically vibrating, the second mass moves as Coriolis force is added to the second mass in a horizontal direction, and a sensing electrode measures displacement of the second mass in the horizontal direction. All moving electrodes and stationary electrodes are disposed on the same surface, and all elements are manufactured by using one mask. Therefore, adhesion between the moving and stationary electrodes is prevented and the manufacturing process is simplified.

Claims

1. A MEMS (micro electro mechanical system) gyroscope comprising:

a first mass which moves in relation to a substrate in a vertical direction of the substrate;

a driving electrode disposed on a same surface with the first mass on the substrate, the driving electrode being operative to drive the first mass in the vertical direction;

a second mass which moves in relation to the substrate in a horizontal direction that is parallel to the surface, the second mass being operative to be moved by a Corilois force generated by an angular velocity applied while the first mass is being vibrated by the driving electrode; and

a sensing electrode which measures a displacement in the horizontal direction of the second mass.

2. The MEMS gyroscope of claim 1, wherein the second mass is able to move in the horizontal direction in relation to the first mass.

3. The MEMS gyroscope of claim 2, further comprising:

at least one first spring to fix the first mass on the substrate for the first mass to be able to move in the vertical direction; and

at least one second spring to fix the second mass and the first mass to each other for the second mass to be able to move in relation to the first mass in the horizontal direction.

4. The MEMS gyroscope of claim 1, further comprising:

at least one first spring to fix the first mass and the second mass to each other for the first mass to be able to move in relation to the second mass in the vertical direction and be fixed in relation to the horizontal direction; and

at least one second spring to fix the second mass on the substrate for the second mass to be able to move in relation to the substrate in the horizontal direction.

5. The MEMS gyroscope of claim 1, wherein the driving electrode and the sensing electrode have a comb structure.

6. The MEMS gyroscope of claim 5, wherein the driving electrode includes:

a stationary electrode erect on the substrate, having a plurality of fixed walls formed parallel to each other, and fixed on the substrate; and

a moving electrode disposed between each of the fixed walls, having a plurality of moving walls with a shorter height than the fixed walls from the substrate, and fixed to the first mass.

7. The MEMS gyroscope of claim 1, further comprising a vertical sensing electrode to sense a displacement in the vertical direction of the first mass moved by the driving electrode.

8. The MEMS gyroscope of claim 7, wherein the vertical sensing electrode includes:

a stationary electrode erect on the substrate, having a plurality of fixed walls formed parallel to each other, and fixed on the substrate; and

a moving electrode disposed between each of the fixed walls, having a plurality of moving walls with a shorter height than the fixed walls from the substrate, and fixed to the first mass.