Microwave oven and method of determining food

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EP 0 615 400 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	05.10.1994 Bulletin 1994/40

(43)	Date of publication A2:
	14.09.1994 Bulletin 1994/37

(21)	Application number: 94300552.0

(22)	Date of filing: 26.01.1994

(51)	International Patent Classification (IPC)⁵: H05B 6/68, H05B 6/80

(84)	Designated Contracting States:
	DE FR GB

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Priority:

11.03.1993 JP 50519/93

(71)	Applicant: KABUSHIKI KAISHA TOSHIBA
	Kawasaki-shi, Kanagawa-ken 210 (JP)

(72)	Inventors:
	Suzuki, Yukio, c/o Aichi Works, K. K. Toshiba Nagoya-shi, Aichi-ken (JP) Kawaguchi, Reiko, c/o Aichi Works, K. K. Toshiba Nagoya-shi, Aichi-ken (JP) Takagi, Minoru, c/o Aichi Works, K. K. Toshiba Nagoya-shi, Aichi-ken (JP) Morita, Mika, c/o Aichi Works, K. K. Toshiba Nagoya-shi, Aichi-ken (JP)

(74)	Representative: Freed, Arthur Woolf et al
	MARKS & CLERK, 57-60 Lincoln's Inn Fields London WC2A 3LS London WC2A 3LS (GB)

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References cited: :

(54)	Microwave oven and method of determining food

(57) Gaseous alcohol and steam emanating from food being heated are detected by an alcohol sensor (11) and a steam sensor (12) respectively. A control circuit (16) obtains maximum values V_Amax and V_Gmax serving as reference values from detection voltages generated by the alcohol and steam sensors (11, 12). Change rates ΔA (V_A/V_Amax) and ΔG (V_G/V_Gmax) are obtained on the basis of detection voltages V_A and V_G detected a predetermined time (40 seconds, for example) after initiation of the heating and a ratio r of the change rates is obtained from the expression,

. The control circuit (16) compares a value of the ratio r with a threshold set for each kind of food to discriminate the kind of the food, thereby setting a subsequent heating time to execute the heating. Since the ratios r vary largely depending upon presence of an alcoholic component contained in the food, the kind of the food can be reliably discriminated.

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