Flow-rate detecting device for heat-sensitive type flow sensor

• US 6,644,113 B2
• Filed: 10/23/2001
• Issued: 11/11/2003
• Est. Priority Date: 04/27/2001
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kawai, Masahiro, Taguchi, Motohisa
• Primary Examiner(s): PATEL, HARSHAD R
• Application Number:
  US09/983,081
• Publication Number:
  US 20020157463A1
• Time in Patent Office: 749 Days
• Field of Search: 732/042.3, 732/042.5, 732/042.6, 732/041.5, 732/041.6, 732/041.1
• US Class Current: 73/204.26
• CPC Class Codes: G01F 1/6845 Micromachined devices

Abstract

A flow-rate detecting device for a heat-sensitive type flow sensor having high reliability. The device includes a planar substrate having first and second through-holes formed therein in juxtaposition with each other, an insulative supporting film formed over one major surface of the substrate so as to cover the through-holes, a fluid temperature measuring resistor formed by a heat-sensitive resistor film deposited at a location of the first through-hole on the supporting film oppositely to the substrate, a heat generating resistor formed of a heat-sensitive resistance film deposited at a location of the second through-hole on the supporting film oppositely to the substrate, an insulative protection film deposited so as to cover the fluid temperature measuring resistor and the heat generating resistor, and a reinforcing film provided for the fluid temperature measuring resistor. The reinforcing film is not provided for the heat generating resistor. Flow rate or alternatively flow speed of a fluid is measured by taking advantage of phenomenon of heat transfer to the fluid from the heat generating resistor.

Claims

1. A flow-rate detecting device for a heat-sensitive type flow sensor, comprising:

a planar substrate having first and second through-holes formed therein in juxtaposition with each other;

an insulative supporting film formed over one major surface of said substrate so as to cover said through-holes;

a fluid temperature measuring resistor formed by a heat-sensitive resistor film deposited at a location of said first through-hole on said supporting film oppositely to said substrate;

a heat generating resistor formed of a heat-sensitive resistance film deposited at a location of said second through-hole on said supporting film oppositely to said substrate;

an insulative protection film deposited so as to cover said fluid temperature measuring resistor and said heat generating resistor; and

a non-metallic reinforcing film provided for said fluid temperature measuring resistor, said reinforcing film being not provided for said heat generating resistor,

wherein flow rate or alternatively flow speed of a fluid is measured on the basis of phenomenon of heat transfer to said fluid from said heat generating resistor.

2. A flow-rate detecting device for a heat-sensitive type flow sensor according to claim 1,

wherein said reinforcing film is deposited at a location of said first through-hole on a surface of said protection film oppositely to said fluid temperature measuring resistor.

3. A flow-rate detecting device for a heat-sensitive type flow sensor according to claim 1,

wherein said reinforcing film is deposited at a location of said first through-hole on a back surface of said supporting film oppositely to said fluid temperature measuring resistor.

4. A flow-rate detecting device for a heat-sensitive type flow sensor according to claim 1,

wherein said reinforcing film is formed of a heat-sensitive resistance film disposed around said fluid temperature measuring resistor.

5. A flow-rate detecting device for a heat-sensitive type flow sensor according to claim 1,

wherein said reinforcing film is so formed as to be embedded in said supporting film at a location of said first through-hole.

6. A flow-rate detecting device for a heat-sensitive type flow sensor according to claim 1,

wherein said reinforcing film is so formed as to be embedded in said protection film at a location of said first through-hole.