Temperature sensor element and temperature sensor including the same

• US 6,081,182 A
• Filed: 11/14/1997
• Issued: 06/27/2000
• Est. Priority Date: 11/22/1996
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Fujii, Eiji, Takayama, Ryoichi, Torii, Hideo, Tomozawa, Atsushi
• Primary Examiner(s): EASTHOM, KARL D
• Application Number:
  US08/970,496
• Time in Patent Office: 956 Days
• Field of Search: 338/22 R, 338/225 D, 338/25, 338/28, 374/185, 374/208, 374/209
• US Class Current: 338/25
• CPC Class Codes: G01K 7/223 characterised by the shape of the resistive element
• CPC Class Codes: H01C 17/30 adapted for baking
• CPC Class Codes: H01C 7/041 formed as one or more layers or coatings
• CPC Class Codes: H01C 7/043 Oxides or oxidic compounds

Abstract

The present invention provides a temperature sensor element having excellent heat resistance, quick heat response, stable resistance, and high reliability with a less variation in resistance against time. The temperature sensor element includes a thermo-sensitive film mainly composed of a heat sensitive material having electrical resistance varies depending on the temperature; a pair of electrode films arranged to measure the electrical resistance in the direction of the thickness of the thermo-sensitive film, a base plate mainly composed of a heat-resistant insulating material for supporting the thermo-sensitive film and the electrode films, an anti-diffusion film interposed between the thermo-sensitive film and the electrode film in the vicinity of the base plate, and a film mainly composed of a heat-resistant insulating material for covering the thermo-sensitive film and the electrode films except the lead-connecting terminals of the electrode films. The thermo-sensitive film is composed of an oxide of corundum crystalline structure represented by the formula of (Al_1-x-y Cr_x Fe_y)₂ O₃, where 0.05≦x+y≦0.95, and 0≦y/(x+y)≦0.6, and the anti-diffusion film is composed of an oxide of corundum crystalline structure represented by the formula of (Al_1-x-y Cr_x Fe_y)₂ O₃, where 0≦x+y≦0.95.

Claims

1. A temperature sensor element comprising:

a thermo-sensitive film comprising a heat sensitive material having an electrical resistance which varies depending on the temperature;

a pair of electrode films, each having a lead-connecting terminal and an end portion opposing said lead-connecting terminal, said end portions of said pair of electrode films arranged on opposite faces of said thermo-sensitive film to provide for measurement of the electrical resistance in a direction transverse to the plane of the thermo-sensitive film

a base plate comprising a heat-resistant insulating material which supports said thermo-sensitive film and said pair of electrode films;

a film comprising a heat-resistant insulating material which covers said thermo-sensitive film and said pair of electrode films except for the lead-connecting terminal of each of said pair of electrode films; and

an anti-diffusion film between said thermo-sensitive film and one of said pair of electrode films which is nearer to said base plate, wherein said anti-diffusion film is formed and heat-treated to form a corundum crystal prior to formation of said thermo-sensitive film such that said anti-diffusion film prevents diffusion of said one of said pair of electrode films into said thermo-sensitive film.

3. The temperature sensor element in accordance with claim 1, wherein said thermo-sensitive film is composed of an oxide of corundum crystalline structure represented by the formula

4. The temperature sensor element in accordance with claim 1, wherein each electrode of said pair of films comprises a thin film of one metal or an alloy or compound of two or more metals selected from the group consisting of platinum, gold, tantalum, rhenium, osmium, iridium, rhodium, ruthenium, palladium, and tungsten.

5. A temperature sensor comprising a temperature sensor element in accordance with claim 1, a metal flange which is capable of fixing said temperature sensor to an object of temperature measurement, a metal housing fixed to said metal flange which covers a part of said temperature sensor element wherein the lead-connecting terminal of each of said pair of electrode films is exposed, lead wires connecting with the lead-connecting terminal of each of said pair of electrode films, a cover which covers a part of said temperature sensor element which is outside of said metal housing, and an electrical insulator arranged in said metal housing which insulates the lead-connecting terminal of each of said pair of electrode films from said metal housing and said metal flange.

8. A temperature sensor comprising a temperature sensor element in accordance with claim 1, a metal flange which is capable of fixing said temperature sensor to an object of temperature measurement, a metal housing fixed to said metal flange which covers a part of said temperature sensor element lead-connecting terminal of each of said pair of electrode films is exposed, lead wires connecting with the lead-connecting terminal of each of said pair of electrode films, a cover which covers a part of said temperature sensor element which is outside of said metal housing, and an electrical insulator arranged in said metal housing which insulates the lead-connecting terminal of each of said pair of electrode films from said metal housing and said metal flange.

2. A temperature sensor element comprising:

a thermo-sensitive film comprising a heat sensitive material having an electrical resistance which varies depending on the temperature;

a pair of electrode films, each having a lead-connecting terminal and an end portion opposing said lead-connecting terminal, said end portions of said pair of electrode films arranged on one face of said thermo-sensitive film;

a third electrode film arranged on another face of said thermo-sensitive film opposite the end portions of said pair of electrode films to provide for measurement of the electrical resistance in a direction transverse to the plane of the thermo-sensitive film;

a base plate comprising a heat-resistant insulating material which supports said thermo-sensitive film, said pair of electrode films, and said third electrode film;

a film comprising a heat-resistant insulating material which covers said thermo-sensitive film, said pair of electrode films, and said third electrode film except for the lead-connecting terminal of each of said pair of electrode films;

an anti-diffusion film between said thermo-sensitive film and said pair of electrode films or said third electrode film, whichever is nearer to said base plate, wherein said anti-diffusion film is formed and heat-treated to form a corundum crystal prior to formation of said thermo-sensitive film such that said anti-diffusion film prevents diffusion of said pair of electrode films or said third electrode film, whichever is nearer to said base plate, into said thermo-sensitive film.

6. The temperature sensor element in accordance with claim 2, wherein said thermo-sensitive film is composed of an oxide of corundum crystalline structure represented by the formula

7. The temperature sensor element in accordance with claim 2, wherein each electrode of said pair of films comprises a thin film of one metal or an alloy or compound of two or more metals selected from the group consisting of platinum, gold, tantalum, rhenium, osmium, iridium, rhodium, ruthenium, palladium, and tungsten.