Control system for electric circuit utilizing photosensitive solid oscillator

Claim 2

A control system for electric load circuit using photosensitive solid oscillator comprising the combination of a photosensitive solid oscillator comprising a semiconductive wafer, a first impurity layer formed on one surface of said wafer, second and third impurity layers formed on the other surface of the wafer as separated from each other, said first, second and third impurity layers being of reverse conducting type with respect to the wafer and containing an impurity of a higher concentration than in the wafer, ohmic electrodes provided respectively on said first, second and third impurity layers, and a source voltage applied through an impedance element between said electrodes on the second and third impurity layers in such that an avalanche between the wafer and one on the second and third impurity layers is produced so that a pulse type oscillation output will be obtained at both ends of said impedance element in such manner that the frequency of said output will vary depending on variation in light amount irradiated on the wafer or in the source voltage, and a load circuit connected to said photosensitive solid oscillator so as to operate depending on said oscillation output at the impedance element, the combination being such that said load circuit is controlled in response to the oscillation output at the both ends of the impedance element which varying depending on variations in either one of the light amount irradiated on the oscillator and the source voltage for the oscillator due to a bias signal applied between the first impurity layer and one of the second and third impurity layers of the oscillator.

Claim 3

A control system of claim 1 wherein said bias signal is provided by a series circuit of a condenser and a resistor and connected between the respective electrodes on the first impurity layer and one of the second and third impurity layers of the oscillator, and said load circuit comprises a circuit including a thyristor and a load element and connected to both ends of the resistor in said series circuit, so that the voltage at the both ends of the resistor will be applied to the gate of said thyristor.

Claim 4

A control system of claim 1 wherein said photosensitive solid oscillator is provided further with a fourth impurity layer formed on the same surface with and between the second and third impurity layers, said fourth impurity layer being of reverse conducting type with respect to the wafer and containing an impurity of a higher concentration than in the wafer, and a biasing ohmic electrode provided on said fourth impurity layer, said biasing signal source comprises a second photosensitive solid oscillator having the same structure with that as defined in claim 1, an impedance element connected between the respective electrodes on the first impurity layer and one of the second and third impurity layers of said second oscillator, and a smoothing condenser connected in paralled to said impedance element, said second oscillator being connected to the first photosensitive solid oscillator in such that the both end output voltage of the impedance element produced when a light is irradiated on the second oscillator will be applied between the both bias electrodes on the first and fourth impurity layers of the first oscillator after smoothed by the smoothing condenser, said load circuit comprises a thyristor and a load element and is connected to the first oscillator in such that the oscillation output signals obtained at both ends of the impedance between the second and third impurity layers of the first oscillator will be applied to the gate of said thyristor, so that when the light amount irradiated on the second osciLlator is large the oscillation produced at output end of the first oscillator will be below a fixed value or stopped so as to cause the thyristor to be non-conducting, and when said light amount is small the said oscillation will be above said fixed value so as to cause the thyristor to be conductive and thereby the load element is actuated.

Claim 5

A control system of claim 1 wherein said bias signal source comprises a series circuit of an input signal source and a biasing direct current source, and said load circuit comprises a mixer and a local oscillator connected to said mixer so as to apply thereto its oscillation voltage, so that the both end output voltage of the impedance of the photosensitive solid oscillator will be applied to said mixer, and the oscillation voltage of said local oscillator of which frequency is selected to be the same with the oscillation frequency of the both end oscillation voltage of said impedance at the time when the signal to said input signal source is zero will be applied to the mixer, whereby a voltage of a frequency in proportional relationship to the voltage at the input signal source is obtained at output end of the mixer.

Claim 6

A control system of claim 1 wherein said voltage source comprises a square wave generating circuit, said load circuit comprises a counting circuit emitting digital signals in response to input signals, said bias signal source is an input signal source, and said square wave generating circuit and said counting circuit are controlled by a control circuit providing start and stop signals, so that, when the voltage from said square wave generating circuit and the bias signal from said input signal source are applied to the photosensitive solid oscillator, the oscillation output of a frequency which varying in response to the magnitude of the input to the input signal source will be provided to the counting circuit.

Claim 7

A control system of claim 1 wherein said bias signal source comprises a comparator circuit which generates a signal of a fixed voltage when analogue signal input and saw-tooth wave signal are applied thereto, and said load circuit comprises a counting circuit emitting digital signals responsive to input signals thereto, so that said counting circuit will be operated by an output voltage obtained at both ends of the impedance of the oscillator in response to the signals of fixed voltage from said comparator circuit.

Claim 8

A control system of claim 1 wherein said load circuit comprises a switching circuit which receives output voltage from the impedance of the oscillator through a frequency discriminator circuit and an amplitude discriminator circuit, so that said switching circuit will be operated in response to the light amount irradiated on the oscillator.