Moisture permeable electrode in a moisture sensor

• US 4,496,931 A
• Filed: 03/16/1984
• Issued: 01/29/1985
• Est. Priority Date: 03/23/1983
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Tanaka, Junichi, Watanabe, Masanori, Hijikigawa, Masaya, Furubayashi, Hisatoshi
• Primary Examiner(s): Envall, Jr., Roy N.
• Assistant Examiner(s): Sears, C. N.
• Application Number:
  US06/590,343
• Time in Patent Office: 319 Days
• Field of Search: 338/35, 338/34, 73/335, 73/336.5, 73/27 R, 422/98, 422/97, 427/101, 427/124, 427/125, 427/126.2, 29/620
• US Class Current: 338/34
• CPC Class Codes: G01N 27/121 for determining moisture content, e.g. humidity, of the fluid moisture content of the tested material G01N27/048
• CPC Class Codes: G01N 27/126 comprising organic polymers

Abstract

A thin-film moisture sensor includes a moisture sensitive polymer film formed on a bottom electrode which is carried on a substrate, and a moisture permeable upper electrode formed on the polymer film. The moisture permeable upper electrode is made of an indium (In) thin-film. In another form, the moisture permeable upper electrode is made of a two-layered electrode including an indium (In) thin-film and a gold (Au) thin-film formed on the indium (In) thin-film.

Claims

1. A thin-film moisture sensor comprising:

a substrate;

a bottom electrode metal layer formed on said substrate;

a moisture sensitive polymer film formed on said bottom electrode layer; and

a moisture permeable indium (In) thin-film formed on said moisture sensitive polymer film.

2. The thin-film moisture sensor of claim 1, wherein said moisture permeable indium (In) thin-film has a thickness of about 400 Å

.

3. The thin-film moisture sensor of claim 2, wherein said moisture permeable indium (In) thin-film is formed by a vacuum evaporation.

4. The thin-film moisture sensor of claim 3, wherein said vacuum evaporation is conducted in an argon (Ar) environment of about 1×

10^-3 Torr, and at a deposition rate of about 0.5 Å

/sec.

5. The thin-film moisture sensor of claim 1, further comprising:

a moisture permeable noble metal thin-film formed on said moisture permeable indium (In) thin-film.

6. The thin-film moisture sensor of claim 5, wherein said moisture permeable indium (In) thin-film has a thickness of about 100 Å

, and said moisture permeable noble metal thin-film consists of a gold (Au) thin-film of about 300 Å

thick.

7. The thin-film moisture sensor of claim 1, wherein said bottom electrode metal layer comprises a pair of comb-shaped thin-film electrodes.