US4656455A
Expired / Lapsed
US
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Humidity-sensing element
Assignee: Toyama Prefecture
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Filing: 1985-07-16
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Granted: 1987-04-07
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Expires: 2005-07-16
Abstract
Abstract A process for fabricating a humidity-sensing element comprises forming an electrode layer on at least one side of a ceramic substrate, applying to the electrode layer a humidity-sensitive paste containing a zirconia, zirconia-yttria, or yttria ceramic as a humidity-sensitive material, drying the coat, and then firing it at a temperature of 750° to 870° C. to form a humidity-sensing part.
Inventors
- 👤 Katsumi Tanino
- 👤 Norihiro Kiuchi
- 👤 Chikara Tominaga
- 👤 Eiji Itoh
- 👤 Kiyoshi Ogino
- 👤 Masataka Yahagi
- 👤 Masaru Sakamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:18
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B35/00; C04B35/01; C04B35/48; C04B35/486; C04B35/50; C04B35/505; C04B41/45; C04B41/52; C04B41/80; C04B41/81; C04B41/89; G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01N27/121
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
196 words
A process for fabricating a humidity-sensing element which comprises the steps of forming a gold electrode layer in a pattern of twin combs on at least one side of a ceramic substrate, preparing a humidity-sensing paste by preliminarily firing a powder of a stabilized solid solution comprising ZrO 2 and Y 2 O 3 at 600° to 800° C., fully firing the powder at 900° to 1100° C., grinding the fired powder into finer particles of -625 mesh, immersing the powder in a 5 to 20% weight percent KOH solution thereby allowing the powder to acquire 1 to 10% by weight of KOH, primarily firing the KOH-containing powder at 800° to 1150° C., adding 1 to 5 mol% of Li 2 CO 3 , secondarily firing the powder at 700° to 900° C., regrinding, and thoroughly kneading the powder with the addition of a suitable resin material to adjust the viscosity of the resulting paste, applying the humidity-sensitive paste thus prepared to the electrode layer by screen printing, to form a coat on the electrode layer, and drying and firing the coat at 500° to 870° C. to form the humidity-sensing part of the humidity-sensing element.
Claim 2
Dependent Claim
196 words
A process for fabricating a humidity-sensing element which comprises the steps of forming a gold electrode layer in a pattern of twin combs on at least one side of a ceramic substrate, preparing a humidity-sensing paste by preliminarily firing a powder of a stabilized solid solution comprising ZrO 2 and Y 2 O 3 at 600° to 800° C., fully firing the powder at 900° to 1100° C., grinding the fired powder into finer particles of -625 mesh, immersing the powder in a 5 to 20% weight percent KOH solution thereby allowing the powder to acquire 1 to 10% by weight of KOH, primarily firing the KOH-containing powder at 800° to 1150° C., adding 1 to 5 mol% of Li 2 CO 3 , secondarily firing the powder at 700° to 900° C., regrinding, and thoroughly kneading the powder with the addition of a suitable resin material to adjust the viscosity of the resulting paste, applying the humidity-sensitive paste thus prepared to the electrode layer by screen printing, to form a coat on the electrode layer, and drying and firing the coat at 500° to 870° C. to form the humidity-sensing part of the humidity-sensing element.
Claim 3
Dependent Claim
24 words
A process according to claim 1 wherein said humidity-sensing element is housed in a case equipped with a filter film of a chlorinated polymer.
Claim 4
Dependent Claim
95 words
A process for fabricating a humidity-sensing element which comprises forming an electrode layer on at least one side of a ceramic substrate, applying to the electrode layer a coat of a humidity-sensitive paste containing a ceramic comprising ZrO 2 , Y 2 O 3 , or mixtures thereof with a member of the group consisting of Li 2 CO 3 and V 2 O 5 as a humidity-sensitive material, drying the coat, and then firing the coat at a temperature of 750° C. to 870° C. to form the humidity-sensing part of the humidity-sensing element.
Claim 5
Dependent Claim
95 words
A process for fabricating a humidity-sensing element which comprises forming an electrode layer on at least one side of a ceramic substrate, applying to the electrode layer a coat of a humidity-sensitive paste containing a ceramic comprising ZrO 2 , Y 2 O 3 , or mixtures thereof with a member of the group consisting of Li 2 CO 3 and V 2 O 5 as a humidity-sensitive material, drying the coat, and then firing the coat at a temperature of 750° C. to 870° C. to form the humidity-sensing part of the humidity-sensing element.
Claim 6
Dependent Claim
21 words
A process according to claim 3, wherein said humidity-sensitive paste contains 1 to 5 mol% of Li 2 CO 3 .
Claim 7
Dependent Claim
99 words
A process for fabricating a humidity-sensing element which comprises forming an electrode layer on at least one side of a ceramic substrate, pretreating a humidity-sensitive material containing a ceramic comprising ZrO 2 , Y 2 O 3 or mixtures thereof by reacting said material with at least one of KOH, K 2 O and K 2 CO 3 , applying to the electrode layer a coat of a paste of said humidity-sensitive material, drying the coat, and then firing the coat at a temperature of 750° C. to 870° C. to form the humidity-sensing part of the humidity-sensing element.
Claim 8
Dependent Claim
99 words
A process for fabricating a humidity-sensing element which comprises forming an electrode layer on at least one side of a ceramic substrate, pretreating a humidity-sensitive material containing a ceramic comprising ZrO 2 , Y 2 O 3 or mixtures thereof by reacting said material with at least one of KOH, K 2 O and K 2 CO 3 , applying to the electrode layer a coat of a paste of said humidity-sensitive material, drying the coat, and then firing the coat at a temperature of 750° C. to 870° C. to form the humidity-sensing part of the humidity-sensing element.
Claim 9
Dependent Claim
40 words
A process according to claim 5 wherein said humidity-sensitive material is immersed in a solution of KOH at a concentration of 5 to 20% by weight and then fired so as to contain 1 to 10% by weight of KOH.
Claim 10
Dependent Claim
92 words
A process for fabricating a humidity-sensing element which comprises forming an electrode layer on at least one side of a ceramic substrate, applying to the electrode layer a coat of a humidity-sensitive paste containing a ceramic comprising ZrO 2 , Y 2 O 3 , or mixtures thereof as a humidity-sensitive material, drying the coat, firing the coat at a temperature of 750° C. to 870° C. to form the humidity-sensing part of the humidity-sensing element, and treating the surface of said humidity-sensing part with KOH or Na 2 CO 3 .
Claim 11
Dependent Claim
92 words
A process for fabricating a humidity-sensing element which comprises forming an electrode layer on at least one side of a ceramic substrate, applying to the electrode layer a coat of a humidity-sensitive paste containing a ceramic comprising ZrO 2 , Y 2 O 3 , or mixtures thereof as a humidity-sensitive material, drying the coat, firing the coat at a temperature of 750° C. to 870° C. to form the humidity-sensing part of the humidity-sensing element, and treating the surface of said humidity-sensing part with KOH or Na 2 CO 3 .
Claim 12
Dependent Claim
93 words
A process for fabricating a humidity-sensing element which comprises forming an electrode layer on at least one side of a ceramic substrate, applying to the electrode layer a coat of a humidity-sensitive paste containing a ceramic comprising ZrO 2 , Y 2 O 3 , or mixtures thereof as a humidity-sensitive material, drying the coat, firing the coat at a temperature of 750° C. to 870° C. to form the humidity-sensing part of the humidity-sensing element, and housing said humidity-sensing element in a case equipped with a filter film of a chlorinated polymer.
Claim 13
Dependent Claim
93 words
A process for fabricating a humidity-sensing element which comprises forming an electrode layer on at least one side of a ceramic substrate, applying to the electrode layer a coat of a humidity-sensitive paste containing a ceramic comprising ZrO 2 , Y 2 O 3 , or mixtures thereof as a humidity-sensitive material, drying the coat, firing the coat at a temperature of 750° C. to 870° C. to form the humidity-sensing part of the humidity-sensing element, and housing said humidity-sensing element in a case equipped with a filter film of a chlorinated polymer.
Claim 14
Dependent Claim
33 words
A process according to claim 8 wherein said filter film has a porosity of 35 to 85%, a pore size of 0.01 to 3 μm, and a thickness of 20 to 200 μm.
Claim 15
Dependent Claim
14 words
A humidity-sensing element fabricated by a process according to any one of claims 1-9.
Claim 16
Dependent Claim
24 words
A process according to claim 3, 5, 7 or 8 wherein said electrode layer is formed by screen printing or vapor deposition of gold.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-06 | 1990-10-06 | 1991-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-06 | 1994-10-06 | 1995-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-06 | 1998-10-06 | 1999-04-07 | $7700.00 | Window Closed / Lapsed |