摘要 |
On a substrate, first and second capacitive portions are formed to have movable diaphragms having different areas for pressure measurement and diagnostic, wherein a communication structure is provided between the cavity spaces of the first and second capacitive portions to equalize the pressure in the first capacitive space to that of the second capacitive space. The different sizes provide different sensitivity for efficient diagnostic. The first and second capacitive portions can be made in one diaphragm, wherein the second capacitive portion is formed around the first capacitive portion. The cavity spaces of the first and second capacitive portions are connected. Moreover, between the first and second capacitive spaces, an insulation portion may be formed in a ring shape to support the diaphragm portion of the first capacitive portion and the diaphragm portion the second capacitive portion with communication portions.
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