Abstract: A variable-gain amplifying device uses different gains for amplifying an input bias voltage signal, and an input composite signal produced by superposing an input bias voltage signal on an input signal, respectively.

Abstract: A signal is read from photodiodes periodically with a predetermined period and applied to the input terminal. The input signal is amplified by an amplifier circuit and switched by a signal switching circuit to be alternately input to two offset cancel circuits through their respective switching elements. The period with which the switching elements are periodically turned on is set to be virtually double the period in the outputting of the signal from the photodiodes. The periods of time at which the switching elements are alternately turned on are shifted virtually half the period from each other. Further, output signals from the offset cancel circuits are adapted to be alternately output through a multiplexer.

Abstract: In an amplifier circuit with an offset cancel circuit, on the output side of a non-inversion amplifier circuit, there is connected a sampling circuit including an analog switch composed of two MOS transistors. A source-follower circuit is connected to the output terminal of the sampling circuit. The output voltage of the source-follower circuit is applied to a series resistance formed between two resistances. A connecting point between the resistances is connected to the inversion input terminal of an operational amplifier forming the non-inversion amplifier circuit and thus the divisional component of the output signal of the source-follower circuit is applied to the inversion input terminal of the operational amplifier.

Abstract: When a forward or reverse voltage is applied to two diodes 1 and 2 connected in series in the same direction, the junction CP of the two diodes is switched for a comparatively low-impedance state to a high-impedance state or vice versa, so that a photoelectric transducer 3 connected to the junction CP is brought to either a reset or storage state. With an improved image pickup device having this construction, the impedance at the junction CP can definitely be held at low level in all instances without being influenced by the amount of illumination on the photoelectric transducer 3, whereby it can be saturated within a predetermined reset time so as to prevent the generation of residual charges.

Abstract: An image sensor capable of reading with high sensitivity at high speed, in which each light-receiving element consists of two photodiodes PD1 and PD2, which comprise a transparent substrate 1, a metal electrode 2, photoelectric transducing layers 3a and 3b, transparent electrodes 4a and 4b and an insulating layer 5, which layers are formed in superposition and patterned to provide PD1 and PD2 that are interconnected in such a way that the relationship of polarities of one photodiode is reverse to that of the other photodiode. The transparent electrode 4a of photodiode PD1 is connected to a common electrode wiring 7 (typically made of aluminum) via a contact hole 6a formed in the insulating layer 5, whereas the transparent electrode 4b of photodiode PD2 is connected to a lead wiring 8 (typically made of aluminum) via a contact hole 6b also formed in the insulating layer 5.

Abstract: An image sensor having a linear array of a plurality of photodetecting element groups each including a plurality of photodetecting elements each consisting of first and second photo diodes connected in series and oppositely in polarity, in which read pulses are applied sequentially to the second photo diodes of the photodetecting elements of each photodetecting element group by a matrix drive system, and image signals are read by a read circuit connected to the first photo diodes of the photodetecting elements. In the image sensor, first capacitor portions are connected to the second photo diodes of the photodetecting elements. A first shift register is connected to the first capacitor portions for each photodetecting element group. The first shift register sequentially applies drive pulses to the photodetecting element groups. Second capacitor portions are connected to the second photo diodes of the photodetecting elements.

Abstract: An image sensor comprising a plurality of light-receiving elements, each of which consists of a pair of photodiodes connected in series-opposition. Since the voltages generated at these photodiodes when equal intensities of light is projected on them are equal to each other, no current leaks, thereby generating no noise.

Abstract: An integrator having a first circuit including an integrating capacitor and a feedback resistor, both being connected in parallel to each other in a negative feedback loop of the first circuit, and a second circuit, connected to an output side of the first circuit, for compensating for a leak by the feedback resistor. The first circuit operates as an integrator in high frequencies, and as a current-voltage converter in low frequencies. Further, the second circuit compensates for the leak by the feedback resistor, thereby to produce a value indicative of the result of integrating an input current.

Abstract: A color image sensor comprises an image reading device, made up of a plurality of sensor elements each reading the image information of corresponding pixels, and an incident light splitter for splitting light to be incident on the sensor elements into a plurality of color components. The light rays incident on the sensors are splitted into a plurality of color components by the incident light splitting means. Each of the color components of the splitted incident light is sequentially read by one sensor.