Acceleration switch

• US 7,009,124 B2
• Filed: 05/13/2004
• Issued: 03/07/2006
• Est. Priority Date: 05/13/2004
• Status: Active Grant

• Current Assignee: Continental Automotive Systems, Inc. (Continental AG)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Chen, Shiuh-Hui Steven, Chiou, Jen-Huang Albert, Ross, Carl A.
• Primary Examiner(s): HOMZA, LISA NHUNG
• Application Number:
  US10/845,381
• Publication Number:
  US 20050252755A1
• Time in Patent Office: 663 Days
• Field of Search: 200/61.45 R, 200/61.45 M, 200/61.48, 200/61.49, 200/61.53, 200/61.5, 735/141.7, 735/141.8, 735/143.8, 735/140.1, 735/141.6, 735/142.1, 735/143.6
• US Class Current: 200/61.45R
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 35/14 Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch wherein the liquid constitutes a contact of the switch H01H29/002

Abstract

An acceleration switch and method therefor includes providing a conductive substrate and an insulating cap. A recessed area is formed in the insulating cap. An insulating layer is disposed on the conductive substrate. A conductive layer is disposed on the insulating layer. The conductive layer is etched to form a cantilever beam and an electrically isolated island. The insulating layer is etched around the cantilever beam to free the cantilever beam to move. Contacts are disposed on the cantilever beam and in the recessed area such that the contacts are able to electrically contact each other upon application of an acceleration to the switch. The cap is bonded to the conductive layer to hermetically seal the cantilever beam.

Claims

1. An acceleration switch comprising:

a substrate;

a conductive layer disposed on the insulating layer, the conductive layer having a cantilever beam and an electrically isolated island formed therein;

an electrically insulating layer disposed between the substrate and the conductive layer, the insulating layer having a recess next to the cantilever beam to allow the cantilever beam to deflect upon an acceleration;

an insulating cap with a recessed area formed on a bottom surface thereof, the cap affixed to the conductive layer to form a hermetically sealed chamber therebetween to contain the cantilever beam and allow the cantilever beam to deflect upon an acceleration; and

a first contact disposed on the cantilever beam and a second contact disposed in the recessed area of the insulating cap such that the contacts are in proximity to each other and able to electrically contact each other upon application of an acceleration to the switch.

2. The switch of claim 1, further comprising electrical connections to each contact and electrode through associated feedthroughs.

3. The switch of claim 2, wherein the feedthroughs are located between a top and bottom surface of the cap and are metalized therethrough to contact the conductive layer to couple to the contacts and electrodes.

4. The switch of claim 2, further comprising solder that fills the feedthroughs.

5. The switch of claim 2, wherein the conductive layer is isotropically etched.

6. The switch of claim 2, wherein the cap is anodic bonded to the conductive layer and the chamber is in substantially a vacuum.