METHOD OF MAKING THIN FILM THERMISTOR

• US 3,831,269 A
• Filed: 08/02/1973
• Issued: 08/27/1974
• Est. Priority Date: 08/02/1973
• Status: Expired due to Term

• Current Assignee: Alfred Sommer
• Original Assignee: Alfred Sommer
• Inventors: Sommer, Alfred
• Primary Examiner(s): Lanham, Charles W.
• Assistant Examiner(s): DiPalma, Victor A.
• Application Number:
  US05/384,949
• Time in Patent Office: 390 Days
• Field of Search: 29/612,621,182.2,182.5 338/22R,25 75/211 148/126
• US Class Current: 29/612
• CPC Class Codes: H01C 7/041 formed as one or more layers or coatings
• CPC Class Codes: Y10T 29/49085 Thermally variable

Abstract

A method of manufacturing a thin film thermistor in which the reagent grade materials are dissolved in water and allowed to intimately mix therein after which the mixture is spray-dried under pressure to obtain a fine powder which is the true thermistor composition desired. After oxidation at high temperatures for a long period of time to remove sulphites etc., the resulting oxides are mixed in a bone milling process with a plastic binder which is then poured on to a glass plate and spread to a predetermined thickness and allowed to dry, after which the material is placed on a ceramic plate and fired to bond the plastic and ceramic and burn out portions of the plastic whereupon electrodes are attached to the final thermistor.

Claims

2. The invention according to claim 1 wherein said organic binder material comprises Bakelite dissolved in methyl alcohol and amyl acetate.

3. The invention according to claim 1 wherein the compounds dissolved in water consist of magnesium sulphate, cobalt sulphate, copper sulphate and nickel sulphate.

4. The invention according to claim 2 wherein said compounds consist of 27.2 percent by weight of magnesium sulphate, 61.9 percent by weight of cobalt sulphate, 9.9 percent by weight of copper sulphate and 1 percent by weight of nickel sulphate.

5. The invention according to claim 1 wherein said solution is spray dried under pressure at the temperature in the range of 500*-700* F.

6. The invention according to claim 5 wherein said resulting powder is fired at a temperature in the range of 900*C for approximately 24 to 48 hours.

7. The invention according to claim 1 wherein said thin film is deposited to be approximately 0.0075 inches thick.

8. The invention according to claim 1 wherein said thin film and substrate is fired for approximately one hour at a temperature in the range of 1250* C.

9. The invention according to claim 2 wherein a portion of the plastic binder is dissolved when placing said cut film on said substrate.

10. The invention according to claim 1 wherein said electrodes are attached by vacuum deposition.