Semiconductor-type pressure sensor with isolation diaphragm with flat portion between corrugations

• US 5,565,629 A
• Filed: 08/10/1994
• Issued: 10/15/1996
• Est. Priority Date: 12/11/1992
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Yamashita, Yasuhiro
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): FELBER, JOSEPH LEON
• Application Number:
  US08/284,583
• Time in Patent Office: 797 Days
• Field of Search: 73/706, 73/708, 73/715-728
• US Class Current: 73/706
• CPC Class Codes: G01L 19/0038 being part of the housing other details about the housing G01L19/14
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection
• CPC Class Codes: G01L 19/143 Two part housings
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means

Abstract

The present invention aims to provide a semiconductor type pressure sensor capable of preventing an occurrence of a thermal output value, thereby improving a linearity of the output with respect to a change in the temperature. The sensor includes housing 8 provided with a pressure detecting chamber 3, a pressure receiving diaphragm 2 arranged to be adjacent the liquid confined in the pressure detecting chamber 3, and a pressure detecting element 4 arranged in the pressure detecting chamber 3 so as to receive the pressure of the liquid. The diaphragm 2 includes at a location adjacent its fixed end a corrugation 2c, which is made of a pair of convex and concave portions 2a and 2b, and a flat portion 2d. A ratio of the distance between the convex and concave portions 2a and 2b, and the radius R of the diaphragm 2, and a ratio of the flat portion 2d and the radius R of the diaphragm 2 are set to respective desired ranges.

Claims

1. A semiconductor type pressure sensor comprising a housing for providing therein a pressure detection chamber;

a pressure receiving diaphragm adjoining a liquid confined in said pressure detection chamber, and;

a pressure detection element arranged to receive the pressure of the liquid in the pressure detection chamber;

said diaphragm having, at a location adjacent its fixed end, only a pair of corrugations comprising a convex and concave portions, and a flat portion of a predetermined length arranged between said convex and concave portions.

2. A semiconductor type pressure sensor according to claim 1, wherein a ratio (L₃ /R) between the predetermined length (L₃) and the radius (R) of the diaphragm is in a range between 0.05 and 0.13.

3. A semiconductor type pressure sensor according to claim 1, wherein a ratio (L₂ /R) between a distance (L₂) from the fixed end to the corrugation adjacent the fixed end and the radius (R) of the diaphragm is in a range which is equal to or smaller than 0.16.

4. A semiconductor type pressure sensor according to claim 1, wherein said diaphragm is made from a metal plate.

5. A semiconductor type pressure sensor according to claim 1, wherein said liquid confined in the pressure detecting chamber is a silicone oil.

6. A semiconductor type pressure sensor according to claim 1, wherein both of said convex and concave portions are formed as a wave shape.