Title:
METHOD AND APPARATUS FOR DETECTING RELATIVE HEIGHT
Document Type and Number:
Japanese Patent JPH0351709
Kind Code:
A
Abstract:
PURPOSE:To achieve mass production at a low cost by containing a pressure detecting means in a case, displacing the means together with a material to be measured, and detecting the amount of displacement based on the pressure difference between the inner side and the outside of the case. CONSTITUTION:Minute air holes 9a are provided in a substrate 9 in a case 11. A capacitor microphone 4 which is a pressure detecting means is accommodated in the case 11. The air at the inside and the outside of the case 11 is circulated through small gaps A - E at the flow-rate resistance having the specified time constant. An electret film 4a is actuated with strain in response to the difference between the pressure which is supplied from the outside and the inner pressure at the rear part. At this time, the case 11 and a material to be measured are displaced in the vertical direction in the atmosphere. The amount of the displacement of the material to be measured in the vertical direction is detected based on the pressure difference in the case 11. Since the microphone 4 which is suitable for mass production can be used, the cost becomes low.
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Inventors:
WATANABE YOSHIJIROU
Application Number:
JP18445589A
Publication Date:
March 06, 1991
Filing Date:
July 19, 1989
Export Citation:
Assignee:
WATANABE YOSHIJIROU
International Classes:
G01C5/06; G01L9/12; (IPC1-7): G01C5/06; G01L9/12
Next Patent: GINBAL MODULE