Abstract: A light receiving element includes: a semiconductor layer; an insulating layer; an interconnect layer; and a film. The semiconductor layer includes a light receiving unit configured to convert a signal light incident on the light receiving unit into an electrical signal. The insulating layer is provided on the semiconductor layer. The interconnect layer is provided on the insulating layer. The film is provided on the insulating layer to cover the light receiving unit and be connected to the interconnect layer, the film being made of a metal or a metal nitride.

Abstract: A light receiving element includes: a semiconductor layer; an insulating layer; an interconnect layer; and a film. The semiconductor layer includes a light receiving unit configured to convert a signal light incident on the light receiving unit into an electrical signal. The insulating layer is provided on the semiconductor layer. The interconnect layer is provided on the insulating layer. The film is provided on the insulating layer to cover the light receiving unit and be connected to the interconnect layer, the film being made of a metal or a metal nitride.

Abstract: According to an embodiment, a light-receiving circuit includes a MOSFET, a first light-receiving element and a second light-receiving element. The first light-receiving element controls a state of the MOSFET between ON state and OFF state by applying a voltage induced by a light signal between a gate of the MOSFET and a source of the MOSFET; and a second light-receiving element controls a threshold voltage of the MOSFET.

Abstract: According to one embodiment, a light receiving circuit includes a light receiving element, a differential circuit, a fifth transistor, and first and second current sources. The differential circuit includes an amplifier and a bias circuit. The amplifier includes a first transistor, a second transistor, and a first feedback resistor. The amplifier is configured to convert a current from the light receiving element into a voltage. The bias circuit includes a third transistor, a fourth transistor, and a second feedback resistor. A reference voltage is supplied to a control electrode of the fourth transistor. The second and third transistors are included in a current mirror circuit. A fifth transistor has a control electrode connected to a connection point between the first and second transistors. A voltage signal switched to a high level or a low level according to a change of an optical signal is outputted.

Abstract: A light receiving element includes: a semiconductor layer; a first layer; and a second layer. The semiconductor layer has a first impurity concentration. The first layer of a first conductivity type is provided inward from an upper surface of the semiconductor layer. The first layer has a second impurity concentration higher than the first impurity concentration. The first layer has a surface region on an upper surface of the semiconductor layer side and an inner region being narrower than the first region. The second layer of a second conductivity type is provided inward from the upper surface of the first semiconductor layer. The second layer has a third impurity concentration higher than the first impurity concentration.

Abstract: A light receiving element includes: a semiconductor layer; an insulating layer; an interconnect layer; and a film. The semiconductor layer includes a light receiving unit configured to convert a signal light incident on the light receiving unit into an electrical signal. The insulating layer is provided on the semiconductor layer. The interconnect layer is provided on the insulating layer. The film is provided on the insulating layer to cover the light receiving unit and be connected to the interconnect layer, the film being made of a metal or a metal nitride.

Abstract: According to one embodiment, a light receiving circuit includes a light receiving element, a differential circuit, a fifth transistor, and first and second current sources. The differential circuit includes an amplifier and a bias circuit. The amplifier includes a first transistor, a second transistor, and a first feedback resistor. The amplifier is configured to convert a current from the light receiving element into a voltage. The bias circuit includes a third transistor, a fourth transistor, and a second feedback resistor. A reference voltage is supplied to a control electrode of the fourth transistor. The second and third transistors are included in a current mirror circuit. A fifth transistor has a control electrode connected to a connection point between the first and second transistors. A voltage signal switched to a high level or a low level according to a change of an optical signal is outputted.

Abstract: According to one embodiment, an optical coupling device is provided. A first photodiode receives an optical signal generated by a light emitting element and converts the optical signal into a first electrical signal. A first inverting amplifier is provided with a first feedback resistor and a first operating amplifier connected in parallel with each other. The input end is connected to a cathode of the first photodiode. A first signal which is obtained by inverting the first electrical signal is output from the output end. A second inverting amplifier is provided with a second feedback resistor and a second operating amplifier connected in parallel with each other. The input end of the second inverting amplifier is connected to a cathode of a second photodiode. The second inverting amplifier outputs a second signal from the output end. A comparator receives the first and second signals and outputs a comparison amplified signal.

Abstract: According to an embodiment, a light-receiving circuit includes a MOSFET, a first light-receiving element and a second light-receiving element. The first light-receiving element controls a state of the MOSFET between ON state and OFF state by applying a voltage induced by a light signal between a gate of the MOSFET and a source of the MOSFET; and a second light-receiving element controls a threshold voltage of the MOSFET.

Abstract: According to one embodiment, an optical coupling device is provided. A first photodiode receives an optical signal generated by a light emitting element and converts the optical signal into a first electrical signal. A first inverting amplifier is provided with a first feedback resistor and a first operating amplifier connected in parallel with each other. The input end is connected to a cathode of the first photodiode. A first signal which is obtained by inverting the first electrical signal is output from the output end. A second inverting amplifier is provided with a second feedback resistor and a second operating amplifier connected in parallel with each other. The input end of the second inverting amplifier is connected to a cathode of a second photodiode. The second inverting amplifier outputs a second signal from the output end. A comparator receives the first and second signals and outputs a comparison amplified signal.

Abstract: A method is described for measuring the amount of analyte present in a sample containing the analyte using a homogeneous amperometric immunoassay. The analyte is chemically bonded to a suitable carrier molecule, which is also chemically bonded to an electroactive molecule. The electroactive molecule, such as ferrocene carboxylic acid, contains a redox center which is capable of transferring a charge to an electrode. A preferred carrier molecule is bovine serum albumin (BSA), while suitable analytes include digoxin, theophylline and HCG. The immunoassay is conveniently performed by applying a voltage to a set of electrodes.

Abstract: A method is described for measuring the amount of analyte present in a sample containing the analyte using a homogeneous amperometric immunoassay. The analyte is covalently bonded to a suitable carrier molecule, which is also covalently bonded to an electroactive molecule. The electroactive molecule, such as ferrocene carboxylic acid, contains a redox center which is capable of transferring a charge to an electrode. A preferred carrier molecule is bovine serum albumin (BSA), while suitable analytes include digoxin, theophylline and HCG. The immunoassay is conveniently performed by applying a voltage to a set of electrodes.