Photo sensor integrated circuit
First Claim
1. A photo sensor integrated circuit comprising:
- photoelectric transfer means for converting received light into photoelectric current when subjected to solar radiation;
signal processing means for processing the photoelectric current of said photoelectric transfer means; and
a semiconductor substrate for integrating said photoelectric transfer means and said signal processing means as one chip component, said semiconductor substrate including a shielding film covering a circuit element that is part of said signal processing means;
wherein an amount of the substrate covered by the shielding film L (μ
m) satisfies the following relationship so as to eliminate malfunction of the signal processing means which may be induced by diffusion of incoming light reaching from outside said shielding film ##EQU7## where Io represents a current generated in said circuit element when subjected to 100,000 lux light irradiation without said shielding film, which Imal(min) represents a minimum current of said circuit element which induces malfunction in said signal processing means under the 100,000 lux light irradiation.
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Accused Products
Abstract
A photo diode and a signal processing circuit are formed on a silicon substrate. The signal processing circuit comprises a PNP transistor and an NPN transistor. A region of the signal processing circuit on the silicon substrate is covered by an aluminum thin film functioning as a shielding film. A covered distance L(μm) is defined as an overhang of the aluminum thin film from the edge of the PNP transistor, and is determined based on a ratio of a minimum current of the PNP transistor, which induces malfunction in the signal processing circuit under the solar radiation, to a current generated in the circuit element when subjected to the solar radiation without the aluminum thin film.
20 Citations
6 Claims
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1. A photo sensor integrated circuit comprising:
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photoelectric transfer means for converting received light into photoelectric current when subjected to solar radiation; signal processing means for processing the photoelectric current of said photoelectric transfer means; and a semiconductor substrate for integrating said photoelectric transfer means and said signal processing means as one chip component, said semiconductor substrate including a shielding film covering a circuit element that is part of said signal processing means; wherein an amount of the substrate covered by the shielding film L (μ
m) satisfies the following relationship so as to eliminate malfunction of the signal processing means which may be induced by diffusion of incoming light reaching from outside said shielding film ##EQU7## where Io represents a current generated in said circuit element when subjected to 100,000 lux light irradiation without said shielding film, which Imal(min) represents a minimum current of said circuit element which induces malfunction in said signal processing means under the 100,000 lux light irradiation. - View Dependent Claims (2, 3)
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4. A photo sensor integrated circuit comprising:
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a semiconductor substrate for integrating components of the circuit; photoelectric transfer means for converting received light into photoelectric current, the photoelectric transfer means being formed on a first portion of a surface of the substrate; signal processing means for processing the photoelectric current, the signal processing means (i) being formed on a second portion of the surface of the substrate, and (ii) integrated with the photoelectric transfer means, the photoelectric transfer means and the signal processing means forming a single chip component; and a shielding film formed on the surface of the substrate and for preventing a malfunction of the circuit when the circuit is subjected to solar radiation, the shielding film (i) covering the signal processing means, (ii) partially covering a remaining portion of the substrate, and (iii) preventing the malfunction of the signal processing means when the substrate is subjected to the solar radiation; wherein an amount of the remaining portion of the substrate covered by the shielding film L (μ
m) satisfies the following relationship so as to eliminate the malfunction of the signal processing means which may be induced by diffusion of incoming light radiating from outside the shielding film ##EQU8## where Io represents a current generated in the circuit when subjected to 100,000 lux light irradiation without the shielding film, while Imal(min) represents a minimum current of a circuit element of the signal processing means which induces the malfunction in the signal processing means under the 100,000 lux light irradiation. - View Dependent Claims (5, 6)
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Specification