Sensor device, and disaster prevention system and electronic equipment each having sensor device incorporated therein

• US 5,830,412 A
• Filed: 08/16/1996
• Issued: 11/03/1998
• Est. Priority Date: 09/30/1993
• Status: Expired due to Fees

• Current Assignee: Nittan Co. Ltd. (Old) (Secom Company Limited)
• Original Assignee: Nittan Co. Ltd. (Old) (Secom Company Limited)
• Inventors: Tanaka, Seiichi, Kimura, Tetsuo, Takahashi, Narimasa, Hashimoto, Ryukichi
• Primary Examiner(s): Spector, Lorraine
• Application Number:
  US08/697,015
• Time in Patent Office: 809 Days
• Field of Search: 422/94, 422/97, 422/98, 422/90, 340/577, 340/578, 340/579, 340/588, 340/589, 340/632, 340/633, 73/31.02, 73/31.06
• US Class Current: 422/90
• CPC Class Codes: G01N 33/0065 using more than one threshold
• CPC Class Codes: G01N 33/0067 by measuring the rate of variation of the concentration
• CPC Class Codes: G08B 17/117 by using a detection device for specific gases, e.g. combustion products, produced by the fire G08B17/103, G08B17/11 take precedence

Abstract

A sensor device of the present invention is capable of surely detecting occurrence of a fire and a type of the fire. The sensor device includes a detection element made of an organic semiconductor element or an inorganic semiconductor element which is varied in characteristic value (i.e., resistance) thereof by both gas produced in a flaming-type fire and a smouldering-type fire and of which a variation in resistance by gas produced in a flaming-type fire is different in polarity from that by gas produced in a smouldering-type fire. A resistance of the detection element is extracted by a resistance extractor and then fed to a resistance decrease discriminator and a resistance increase discriminator, wherein a decrease or increase in resistance of the element is discriminated. An information output circuit outputs a predetermined signal depending on discrimination results provided by the discriminators, to thereby detect occurrence of a fire and/or a type of the fire.

Claims

1. A sensor device comprising one detection element made of a substrate, a semiconductor layer on said substrate, and spaced-apart electrodes in contact with said semiconductor layer, wherein said semiconductor layer is selected to be of a given conductivity type and has a property of varying a predetermined characteristic value thereof in one direction of polarity in response to exposure of said detection element to electron acceptor gas produced by a flaming type of fire and of varying the predetermined characteristic value thereof in an opposite direction of polarity in response to exposure of said detection element to electron donor gas produced by a smouldering type of fire, and characteristic value discrimination means coupled to the electrodes of said one detection element which discriminates a variation in the predetermined characteristic value thereof in the one polarity direction as being produced by electron acceptor gas indicating a flaming type of fire, and discriminates a variation of the predetermined characteristic value in the other polarity direction as being produced by electron donor gas indicating a smouldering type of fire, so that occurrences of both types of fires which generate the two different kinds of gases may be detected by said one detection element.

2. A sensor device according to claim 1, wherein organic semiconductor elements including metal substituted phthalocyanines, metal substituted phthalocyanines to which metal oxides are added, or ion-doped polymers are used as said detection element, or inorganic semiconductor elements including a metal oxide having electric conductivity of a semiconductor level are used as said detection element.

3. An electronic equipment according to claim 1, further comprising a power supply for supplying an electric power to components of said electronic equipment;

wherein said power supply is operated so as to interrupt supply of the electric power to said components of said electronic equipment when said sensor device detects fire.

4. A sensor device according to claim 1, wherein said sensor device is provided with:

a detection means including said one detection element; and

said characteristic value discriminating means is coupled to characteristic monitoring means which outputs a fire occurrence signal and a fire type signal depending on the variation in predetermined characteristic value of said detection element.

5. A sensor device according to claim 4, wherein the characteristic value of said one detection element is a resistance which increases upon exposure to one of said first and second kinds of gas and decreases upon exposure to the other of said first and second kinds of gas;

and

said characteristic monitoring means includes a resistance decrease discriminating means for discriminating whether the resistance extracted from said detection element is decreased by a predetermined amount within a predetermined time period, a resistance increase discriminating means for discriminating whether the resistance extracted is increased by a predetermined amount within a predetermined time period, and an information output means for outputting said fire occurrence and type signals depending on a discrimination result provided by each of said resistance decrease discriminating means and resistance increase discriminating means.

6. A sensor device according to claim 5, wherein said information output means includes an abnormality occurrence output means for outputting abnormality occurrence information at any time when said resistance decrease discrimination means provides a discrimination result indicating a decrease in resistance or when said resistance increase discrimination means provides a discrimination result indicating an increase in resistance.

7. A sensor device according to claim 5, wherein said information output means includes an abnormality property output means for outputting first abnormality property information when said resistance decrease discrimination means provides a discrimination result indicating a decrease in resistance and for outputting second abnormality property information when said resistance increase discrimination means provides a discrimination result indicating an increase in resistance.

8. A sensor device according to claim 5, further including a conventional sensor providing a detection result, and wherein said information output means combines the detection result provided by the conventional sensor with the discrimination results provided by said resistance decrease discrimination means and resistance increase discrimination means to output said fire occurrence and type signals.

9. A sensor device according to claim 4, wherein said one detection element is a first detection element of a predetermined first conductivity type and said sensor device includes a second detection element of a predetermined second conductivity type opposite to said first conductivity type which is connected in series therewith, each of said first and second detection elements being made of a material having a property of varying a resistance thereof in one direction of polarity in response to electron acceptor gas and of varying the resistance thereof in an opposite direction of polarity in response to electron donor gas, and said first and second detector elements being electrically connected to each other in a manner so as to double the response of the resistance extracted in each direction of polarity;

and

wherein said characteristic monitoring means includes a resistance decrease discriminating means for discriminating whether the resistance extracted is decreased by a predetermined amount within a predetermined period of time, a resistance increase discriminating means for discriminating whether the resistance extracted is increased by a predetermined amount within a predetermined period of time, and an information output means for outputting said fire occurrence and type signals depending on a discrimination result provided by each of said resistance decrease discriminating means and resistance increase discriminating means.

10. An electronic equipment according to claim 9, wherein detection elements used in said sensor device are mounted on circuit boards on which electric circuits for said electronic equipment are mounted.