Sensing unit and method of making same

• US 20080313882A1
• Filed: 06/20/2007
• Published: 12/25/2008
• Est. Priority Date: 06/20/2007
• Status: Active Grant

• Current Assignee: Headway Technologies Incorporated, SAE Magnetics Limited (TDK Corporation)
• Original Assignee: Headway Technologies Incorporated, SAE Magnetics Limited (TDK Corporation)
• Inventors: Ishizaki, Kazuo, Sasaki, Yoshitaka, Horinaka, Takehiro, Tanemura, Shigeki, Shimizu, Tatsushi
• Granted Patent: US 7,698,941 B2
• Time in Patent Office: Days
• US Class Current: 29/592.1
• CPC Class Codes: G01P 15/08 with conversion into electric or magnetic values
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/105 by magnetically sensitive devices
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49007 Indicating transducer
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49146 with encapsulating, e.g., potting, etc.
• CPC Class Codes: Y10T 29/49171 with encapsulating
• CPC Class Codes: Y10T 29/49176 with molding of electrically insulating material
• CPC Class Codes: Y10T 29/4922 with molding of insulation

Abstract

In a sensing unit according to the present invention, a spring portion having a support portion and a movable portion is conductive. A signal of a sensor portion provided on the movable portion of the spring portion is transmitted via the spring portion. Hence, the sensing unit according to the present invention has a simple constitution with a small number of components, and a wire does not necessarily have to be provided for each sensor portion. As a result, a reduction in manufacturing cost, simplification of the manufacturing process, and so on are achieved.

Claims

1. A sensing unit comprising:

a spring portion formed from a conductive material and having a support portion provided on a substrate and a movable portion supported by said support portion so as to be capable of floating relative to said substrate; and

a sensor portion provided on said movable portion of said spring portion, for detecting displacement in said movable portion and transmitting a signal relating to said displacement via said spring portion.

2. The sensing unit according to claim 1, wherein

a recessed portion is formed in said substrate,

said support portion of said spring portion is positioned on an edge portion of said recessed portion, and

said movable portion of said spring portion is positioned above said recessed portion in a flat coil shape.

3. The sensing unit according to claim 2, wherein said substrate is held so as to extend in a vertical direction.

4. The sensing unit according to claim 2, wherein said substrate is held so as to extend in a horizontal direction.

5. The sensing unit according to claim 1, wherein two end portions of said movable portion are supported by a pair of said support portions, and

a part of said movable portion extends in an arrangement direction of said pair of support portions and oscillates in said arrangement direction.

6. The sensing unit according to claim 1, wherein said spring portion is formed by plating.

7. The sensing unit according to claim 1, wherein said sensor portion is constituted by a GMR sensor.

8. A method of making a sensing unit having:

a spring portion having a support portion provided on a substrate and a movable portion supported by said support portion so as to be capable of floating relative to said substrate; and

a sensor portion provided on said movable portion of said spring portion, for detecting displacement in said movable portion and transmitting a signal relating to said displacement via said spring portion,

said method comprising the steps of;

preparing a substrate on which a first region for forming said movable portion of said spring portion is lower than a second region for forming said support portion;

burying said first region in a resist layer such that said substrate is made flat;

forming a plating layer that is to become said spring portion such that a part that is to become said movable portion is positioned on said resist layer in said first region and a part that is to become said support portion is positioned in said second region;

forming said sensor portion in said part of said plating layer that is to become said movable portion; and

removing said resist layer.