JP4617519B2 - Monitor sensor output circuit, output control method, and CCD image pickup device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a monitor sensor output in which the amount of light corresponds to an accumulated charge, and more particularly to a monitor sensor output circuit and an output control method that are provided with a plurality of monitor sensors and are accompanied by an improvement in the number of terminals corresponding to each output.
[0002]
[Prior art]
When a CCD imaging device (area sensor, linear sensor) in a CCD (Charge Coupled Device) solid-state imaging device has a plurality of monitor sensors, an output terminal corresponding to each of the plurality of sensors is provided.
[0003]
For example, consider a CCD linear sensor with a plurality of monitor sensors. For each sensor array, a monitor sensor light receiving unit, an electrode unit for picking up the sensor voltage, a reset gate for sweeping the sensor charge to the drain and accumulating in the sensor, a reset drain for discarding unnecessary charges, a buffer, and the like are configured. The
[0004]
One output terminal is required for each of the plurality of sensor units. Suppose that an output changeover switch or the like is simply provided and the output is switched to make one terminal. In this case, it is generally considered that the control form is related to the accumulation of the next sensor after completion of accumulation of a predetermined sensor. In such a form, it takes time until the output of all the sensors is completed. Unless the control form can reduce the charge storage time of the sensor, it will not be an advantageous product for monitoring even if the output terminals can be reduced.
[0005]
[Problems to be solved by the invention]
Thus, conventionally, when there are a plurality of monitor sensors, the charge accumulation state of the sensor is output from each terminal, so that the number of terminals is required accordingly. As a result, there is a problem that the chip area increases.
[0006]
The present invention has been made in view of the above circumstances, and its problem is to provide a monitor sensor output circuit and an output control method in which a plurality of monitor sensors are provided and the number of terminals for each output corresponding thereto is reduced. It is to provide.
[0007]
[Means for Solving the Problems]
The monitor sensor output circuit according to the present invention includes a plurality of monitor sensors, an output terminal sharing a data output corresponding to the accumulated charge of each of the plurality of monitor sensors, a transmission path of each data output, and the output terminal. And a selection control circuit for controlling the output changeover switch.
[0008]
The present invention is an output control method of a monitor sensor output circuit that monitors data output of a plurality of monitor sensors in real time, the output terminal sharing a data output corresponding to the accumulated charge of each of the plurality of monitor sensors, An output changeover switch provided between each data output transmission path and the output terminal; and a selection control circuit for controlling the output changeover switch. The output changeover switch is controlled so that the output is switched during charge accumulation of the monitor sensor and transmitted to the output terminal.
[0009]
The present invention is a CCD image pickup device including a plurality of monitor sensors, an output terminal sharing a data output corresponding to the accumulated charge of each of the plurality of monitor sensors, a transmission path of each data output, and the output terminal. And a selection control circuit for controlling the output changeover switch.
[0010]
According to the present invention, since the selection control circuit for selecting which sensor to output is a separate system from the system that controls the operation of the sensor itself, any sensor can be accumulated without waiting for the completion of accumulation of a specific sensor. It is.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
First, a CCD linear sensor having three monitor sensors will be described with reference to FIGS. FIG. 4 is a circuit block diagram showing a CCD linear sensor (CCD sensor is omitted) having three monitor sensors, and FIG. 5 is an output waveform diagram relating to the operation of the configuration of FIG.
[0012]
In FIG. 4, for each sensor row, a monitor sensor light receiving unit (monitor sensor), an electrode unit (pickup contact) for picking up the voltage of each sensor, a reset gate for sweeping the sensor charge to the drain or accumulating in the sensor, A reset drain for discarding unnecessary charges and a buffer are configured. Three output terminals, such as Mout-A, Mout-B, and Mout-C, are provided for receiving signals from buffers corresponding to the sensors. The power supply voltage Vdd indicates a signal level voltage source related to signal transmission from the signal to the reset gate to the output terminal.
[0013]
The circuit operation of the above configuration will be described with reference to FIGS. When charge is not accumulated, the reset gate is on, and the charge of the sensor portion is being swept out to the reset drain. When charge accumulation is started, the reset gate is turned off. As a result, charge accumulation starts, and the potential of the sensor unit fluctuates due to the charge photoelectrically converted by the sensor, and the fluctuation is output in real time via the pickup contact and each buffer.
[0014]
In contrast to the above configuration, the configuration of the present invention further includes a sensor selection switch and a sensor selection control circuit for controlling the switch, so that the sensor to be output can be selected.
[0015]
FIG. 1 is a circuit block diagram showing a CCD linear sensor (CCD sensor is omitted) having a plurality of (three) monitor sensors according to the first embodiment of the present invention, and FIG. 2 is a block diagram of the configuration of FIG. It is an output waveform diagram of each part regarding circuit operation.
[0016]
In this embodiment, in the circuit block configured as shown in FIG. 4, when the output terminal of Mout is made one, a sensor selection output changeover switch SW and a sensor selection control circuit SSC for controlling the switch SW are provided. ing.
[0017]
The configuration of FIG. 1 is similar to the circuit block of the configuration of FIG. 4 described above, for example, monitor sensor light receiving portions (monitor sensors) A, B, C, electrode portions (pickup contacts) PUC for picking up the voltages of these sensors, sensors A reset gate RG that sweeps out the electric charge to the drain or accumulates it in the sensor, a reset drain RD that discards unnecessary charges, and buffers BF-A, BF-B, and BF-C are configured.
[0018]
Further, the sensor selection output changeover switch SW is provided between the final stage buffer BFO connected to one output terminal Mout and the transmission paths of the buffers BF-A, BF-B, and BF-C. The switch SW selects one of the sensors under the control of the sensor selection control circuit SSC, and its output data is obtained at the output terminal Mout via the buffer BFO. The power supply voltage Vdd indicates a signal level voltage source related to signal transmission from the signal to the reset gate to the output terminal.
[0019]
The circuit operation of the above configuration will be described with reference to FIG. In the sensor selection control circuit SSC, control signals φSEL-A, φSEL-B, and φSEL-C for the output changeover switch SW are generated. Signal φSEL-A selects the output of sensor A from the buffer at a high level. The signal φSEL-B selects the output of the sensor B from the buffer at a high level. The signal φSEL-C selects the output of the sensor C from the buffer at a high level.
[0020]
Signal φRS-A is a signal input to the reset gate of sensor A, signal φRS-B is a signal input to the reset gate of sensor B, and signal φRS-C is a signal input to the reset gate of sensor C. These signals φRS-A, B, and C respectively sweep out the charge of the corresponding sensor at a high level, and store the charge of the corresponding sensor at a low level.
[0021]
During the period t1, the sensor A is selected, and output data with a large amount of light, for example, from the sensor A is obtained at the output terminal Mout. In the period t2, the sensor B is selected, and output data with a medium amount of light from the sensor B is obtained at the output terminal Mout. In the period t3, the sensor C is selected, and output data with a small amount of light from the sensor C is obtained at the output terminal Mout.
[0022]
According to the above configuration, signals from a plurality of sensors can be output from one output terminal Mout. Thereby, reduction of the number of terminals is realized. In addition, a sensor selection control circuit SSC that supplies a signal (φSEL-A, B, C) for selecting which sensor to output, and a signal (φRS-A, B for the reset gate RG that controls the operation of the sensor itself. , C) is a separate system, it is possible to store arbitrary sensors without waiting for completion of storage of specific sensors.
[0023]
FIG. 3 is an output waveform diagram of each part showing an output control method of a CCD linear sensor having a plurality (three) of monitor sensors according to the second embodiment of the present invention. The CCD linear sensor (CCD sensor is omitted) used has the configuration shown in FIG.
[0024]
In this embodiment, charge accumulation of each sensor is performed simultaneously and the output is switched. That is, as shown in the figure, the output switching is selected in the order of sensor A → sensor B → sensor C by the control signal φSEL-A, B, C of the output selector switch SW.
[0025]
Thereby, first, in the period t11, the sensor A has a small amount of light, for example, and drops in potential to the level LV1. Next, in the period t12, for example, the light amount of the sensor B is medium, so that the potential drops to the level LV2 when the sensor B is selected even in the same accumulation time. The selection of the sensor B is continued as it is, and the sensor B decreases to the level LV3 with the potential decreasing slope. Next, in the period t13, for example, the sensor C has a large amount of light, and the potential drops to the level LV4 when the sensor C is selected even in the same accumulation time. The selection of the sensor C continues as it is, and the output potential further decreases until the signal φRS-C that maintains the charge accumulation state in the sensor C becomes high level while the inclination of the potential decrease in the sensor C remains.
[0026]
According to the method for simultaneously accumulating charges according to the above embodiment, the signals of the respective sensors can be monitored by switching the sensor selection by the sensor selection control circuit SSC and the output changeover switch SW. This is effective when determining which sensor has the largest amount of light. Further, regarding the output inspection of each sensor at the time of production and shipment, it is possible to shorten the inspection time by accumulating at a time rather than accumulating and inspecting separately. Therefore, a sufficient cost merit can be expected.
[0027]
In each of the above embodiments, the monitor sensor output circuit and the output control method of the present invention have been described by taking a CCD linear sensor as an example. However, the present invention can be applied to all CCD image pickup devices including an area sensor. Moreover, it is applicable not only to CCD but also to other sensors.
[0028]
【The invention's effect】
As described above, according to the present invention, a plurality of monitor sensors are provided, and an output changeover switch is provided for each output corresponding to the monitor sensor, so that it can be arbitrarily selected. Thereby, first, the reduction of the number of output terminals can be achieved, which contributes to the reduction of the chip area. Second, the output of each sensor can be monitored in real time. In addition, by applying a method such as collecting sensors simultaneously and starting charge accumulation, the sensor accumulation time can be shortened, and the inspection time can be easily shortened. With such advantages, the chip cost can be reduced, and a highly reliable monitor sensor output circuit and output control method can be provided.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram showing a CCD linear sensor having a plurality of monitor sensors according to a first embodiment of the present invention.
FIG. 2 is an output waveform diagram of each part related to the circuit operation of the configuration of FIG. 1;
FIG. 3 is an output waveform diagram of each part showing an output control method of a CCD linear sensor having a plurality of monitor sensors according to a second embodiment of the present invention.
FIG. 4 is a circuit block diagram showing a CCD linear sensor having a plurality of monitor sensors related to the technology underlying the present invention.
5A to 5C are output waveform diagrams relating to the operation of the configuration of FIG.
[Explanation of symbols]
A, B, C ... monitor sensor, PUC ... electrode part (pickup contact), RG ... reset gate, RD ... reset drain, BF-A, BF-B, BF-C, BFO ... buffer, SW ... output selector switch, SSC: Sensor selection control circuit.

Claims (5)

Each has a monitor sensor light receiving unit, an electrode unit for picking up the voltage of the monitor sensor light receiving unit, a reset drain for sweeping away unnecessary charges accumulated in the monitor sensor light receiving unit, and a buffer connected to the electrode unit. In addition, when signals for determining the sweep timing of the charge accumulated in the monitor sensor light receiving unit are independently input, the charge sweeping of the charge accumulated in the monitor sensor light receiving unit can be independently performed, and the monitor sensor A plurality of monitor sensors that perform charge accumulation in the light receiving unit and output from the buffer;
An output terminal sharing a data output corresponding to the accumulated charge of each of the plurality of monitor sensors;
An output changeover switch provided between the transmission path of each data output and the output terminal;
A monitor sensor output circuit comprising: a selection control circuit for controlling the output changeover switch; Each has a monitor sensor light receiving unit, an electrode unit for picking up the voltage of the monitor sensor light receiving unit, a reset drain for sweeping away unnecessary charges accumulated in the monitor sensor light receiving unit, and a buffer connected to the electrode unit. In addition, when signals for determining the sweep timing of the charge accumulated in the monitor sensor light receiving unit are independently input, the charge sweeping of the charge accumulated in the monitor sensor light receiving unit can be independently performed, and the monitor sensor An output control method of a monitor sensor output circuit for monitoring in real time the data output of a plurality of monitor sensors that perform charge accumulation in a light receiving unit and output from the buffer,
An output terminal sharing a data output corresponding to the accumulated charge of each of the plurality of monitor sensors, an output changeover switch provided between the transmission path of each data output and the output terminal, and the output changeover switch are controlled. A selection control circuit,
An output control method for a monitor sensor output circuit, wherein the output control switch is controlled by the selection control circuit so that the data output of each of the plurality of monitor sensors is switched during charge accumulation of the monitor sensor and transmitted to the output terminal. The output control method of the monitor sensor output circuit according to claim 2, wherein the charge accumulation of the plurality of monitor sensors is controlled to start simultaneously. Each has a monitor sensor light receiving unit, an electrode unit for picking up the voltage of the monitor sensor light receiving unit, a reset drain for sweeping away unnecessary charges accumulated in the monitor sensor light receiving unit, and a buffer connected to the electrode unit. In addition, when signals for determining the sweep timing of the charge accumulated in the monitor sensor light receiving unit are independently input, the charge sweeping of the charge accumulated in the monitor sensor light receiving unit can be independently performed, and the monitor sensor A CCD image pickup device including a plurality of monitor sensors that perform charge accumulation in a light receiving unit and output from the buffer;
An output terminal sharing a data output corresponding to the accumulated charge of each of the plurality of monitor sensors;
An output changeover switch provided between the transmission path of each data output and the output terminal;
A CCD image pickup device comprising: a selection control circuit for controlling the output changeover switch. 5. The CCD image pickup device according to claim 4, wherein the selection control circuit controls the output changeover switch so that a data output of each of the plurality of monitor sensors is switched during charge accumulation of the monitor sensor and is transmitted to the output terminal.

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