Minolta Company, Ltd.

Yoshio Hagihara

Kenji Takada

Tomokazu Kakumoto

Shigehiro Miyatake

Satoshi Nakamura

In a solid-state image-sensing device, after completion of image sensing by individual pixels, in each pixel, a signal &#x3c6;VRB fed to a capacitor Cconnected to the gate of a first MOS transistor Tis turned to a high level to make it easy for a negative electric charge to flow into the MOS transistor T. This permits quick recombination of the positive electric charges accumulated at the drain and gate of the MOS transistor T, at the gate of a MOS transistor T, at the anode of a photodiode, and in a capacitor C, and thereby makes quick resetting possible.

Solid-state logarithmic image sensing device

In a solid-state image-sensing device, when an image sensing operation is performed in each pixel, a MOS transistor Tis turned on and a MOS transistor Tis turned off to make a MOS transistor Toperate in a subthreshold region. When a reset operation is performed in each pixel, the MOS transistor Tis turned off and the MOS transistor Tis turned on to feed a constant voltage to the gate and drain of the MOS transistor TThen, the MOS transistor Tis turned off, then the voltage at the node 'a' is reset, and then a pulse signal &#x3c6;V is fed to a MOS transistor Tto obtain an output. By using the thus obtained output as compensation data, variations in sensitivity among individual pixels are reduced.

Solid-state image-sensing device

In a solid-state image-sensing device, when image sensing is performed, in each pixel, MOS transistors Tand Tare turned on and a MOS transistor Tis turned off so that a MOS transistor Toperates in a subthreshold region. When resetting is preformed, in each pixel, the MOS transistors Tand Tare turned off and the MOS transistor Tis turned on so that the gate voltage of the MOS transistor Tis kept constant. In this state, the MOS transistor Tis brought first into a conducting state and then, by turning a signal &#x3c6;VPS to a high level, into a cut-off state. This permits a signal proportional to the threshold value of the MOS transistor Tto be output as compensation data.

Image-sensing apparatus

Based on the output signal of an area sensor, a level adjustment circuitadjusts the bias voltage fed to the transistors provided within the individual pixels of the area sensorand operating in a subthreshold region and thereby adjusts the level of the output signal of the area sensor. According to whether the subject is illuminated with intense or dim light, the level of the output signal is lowered or raised, respectively.

Image-sensing device

To reduce variations in output current of individual pixels resulting from variations in threshold voltage of the MOS transistor Tprovided in each pixel, the threshold voltage of the MOS transistor Tof each pixel is measured to acquire compensation data with which to correct the output current from the individual pixels. To acquire this compensation data, first, a MOS transistor Tis turned on to apply a direct-current voltage VRB to the gate of the MOS transistor T, and the MOS transistor Tis turned off to disconnect the gates of the MOS transistors Tand Tfrom each other. Next, in this state, by turning a signal &#x3c6;VPS first to a low voltage and then to a voltage close to a direct-current voltage VPD, a negative electric charge is accumulated in the MOS transistor T. A voltage resulting from this negative electric charge is applied to the gate of the MOS transistor T, and thus the MOS transistor Tis turned on, causing an output current to be fed to an output signal linein accordance with the voltage applied to the gate of the MOS transistor T

In a solid-state image-sensing device, first a switch Swa is turned on to sample and hold an image signal in a capacitor Ca, and then the switch Swa is turned off. Next, a switch SWb is turned on to sample and hold a noise signal in a capacitor Cb, and then the switch SWb is turned off. Next, switches SWand SWare turned on simultaneously so that the image signal in the capacitor Ca is fed through a bufferto a capacitor Cc, and then the switches Swand Sware turned off. Then, a switch SWis turned on to reset the input side of the bufferNext, switches SWand SWare turned on simultaneously so that the noise signal in the capacitor Cb is fed through the buffer to a capacitor Cd, and then the switches SWand SWare turned off. Then, the switch SWis turned on to reset the input side of the bufferagain.

A scanning circuit operates at a driving speed approximately twice the conventional speed when clock signals having the same frequency as those in the prior art are supplied. By alternately driving the switches in even-numbered and odd-numbered transfer stages Tto Tn, the input side and the output side of each transfer stage are simultaneously made high in order of T, T, . . . and Tn. Logical AND circuits are connected to the even- and odd-numbered stages to output pulse signals for scanning at intervals shorter than the clock period.

Scanning circuit, and imaging apparatus having the same

In a solid-state image-sensing device, when an image sensing operation is performed in each pixel, a MOS transistor Tis turned on and a MOS transistor Tis turned off to make a MOS transistor Toperate in a subthreshold region. When a reset operation is performed in each pixel, the MOS transistor Tis turned off and the MOS transistor Tis turned on to feed a constant voltage to the gate and drain of the MOS transistor T. Then, the MOS transistor Tis turned off, then the voltage at the node 'a' is reset, and then a pulse signal &#x3c6;V is fed to a MOS transistor Tto obtain an output. By using the thus obtained output as compensation data, variations in sensitivity among individual pixels are reduced.

In a photoelectric converting device, a photoelectric current (electric signal) generated by light entering a photodiode PD causes the gate voltage of MOS transistors Tand Tto rise, and thus a current corresponding to this gate voltage flows through the MOS transistor Tinto a capacitor C, shifting the voltage at the node 'a' between the MOS transistor Tand the capacitor C. Here, when the voltage &#x3c6;VPS applied to the source of the MOS transistor Tis adjusted in such a way that the MOS transistor Toperates in a subthreshold region below its threshold level, the voltage at the node 'a' varies on a natural-logarithm basis with respect to the photoelectric current. By contrast, when the voltage &#x3c6;VPS applied to the source of the MOS transistor Tis kept approximately equal to a direct-current voltage VPD, the voltage at the node &#x201c;a&#x201d; varies on a linear basis with respect to the photoelectric current.

Photoelectric converting device

A solid-state image-sensing device has a photosensitive element that produces an electric signal commensurate with the amount of light incident thereon, a transistor of which the first electrode and the control electrode are connected to one electrode of the photosensitive element, and a resetting portion for resetting the transistor by feeding a predetermined pulse signal to the second electrode of the transistor. The resetting portion resets the transistor in such a way as to inhibit the transistor from operating in a subthreshold region when the amount of light incident on the photosensitive element is below a predetermined level.

Solid-state image sensing device

A solid-state, two-dimensional image sensing device having a matrix of pixels each of which employs a photosensor that generates a photocurrent and a MOS circuit which outputs a signal proportional to the logarithm of the integral over time of the photocurrent. The sensor includes an integration control switching device so that all pixels in the array have equal integration time. The sensor integrates the signal for each pixel for a period of time and stores the integrated signal in a pixel signal storage location. To read out the stored signal each pixel includes an amplifier to increase the signal during read out. The sensor further accumulates signal in either a MOS transistor pn-junction or a secondary pixel storage location during a time that the integrated pixel signal is being read out so that image information can be collected continuously even while the integrated pixel signal for each pixel is being read.

Image pickup device with integral amplification

A solid-state, two-dimensional image sensing device having a matrix of pixels each of which employs a photosensor that generates a photocurrent and a MOS circuit which outputs a signal proportional to the logarithm of the integral over time of the photocurrent. The sensor includes an integration control switching device so that all pixels in the array have equal integration time. The sensor integrates the signal for each pixel for a period of time and stores the integrated signal in a pixel signal storage location. The sensor further accumulates signal in a MOS transistor pn-junction during a time that the integrated pixel signal is being read out so image information can be collected continuously even while the integrated pixel signal for each pixel is being read.

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Amagasaki, Japan

Yoshio Hagihara