Sensor chip and photoelectric conversion apparatus using the same

Abstract: A sensor chip includes output signal lines for outputting signals outside the sensor chip from light-receiving elements of the sensor chip, a switch for connecting/disconnecting the output signal lines, and a controller for closing the switch only for a duration including a time interval in which signals are output outside the sensor chip from the light-receiving elements, and opening the switch for a duration except for the duration. A multichip photoelectric conversion apparatus in which a plurality of sensor chips each having a plurality of light-receiving elements are arranged, includes output signal lines, connected to a common signal line, for outputting signals outside the sensor chip from light-receiving elements of the sensor chip, a switch, provided for each of the sensor chips, for connecting/disconnecting the output signal lines, and a controller, provided in each of the sensor chips, for closing the switch only for a duration including a time interval in which signals are output outside the sensor chip from the light-receiving elements, and opening the switch for a duration except for the duration.

Description: BACKGROUND OF THE INVENTION : Field of the Invention The present invention relates to a sensor chip and a photoelectric conversion apparatus using the same and, more particularly, to a multichip photoelectric conversion apparatus using an array of a plurality of sensor chips. Related Background Art Conventionally, a photoelectric conversion apparatus (linear image sensor) in which light-receiving elements are arranged in a line has been widely used in an image reading apparatus such as a facsimile, a digital copying machine, and a scanner. Since a sensor chip for use in a linear image sensor is generally made from a silicon wafer, the sensor length is limited by the wafer size. Therefore, it is difficult to manufacture a linear image sensor chip having a length identical to the width of an original to be read having a general size. For this reason, in order to use a single sensor chip, an imaging optical system is used to image an original to be read on the sensor chip in a reduced scale, thereby reading an image carried by the original. An apparatus utilizing such a reduction imaging optical system, however, requires a space for the optical system. Therefore, it is difficult to make the apparatus compact. In addition, it is difficult to obtain a sufficient resolution. For this reason, a so-called multichip image sensor in which a plurality of linear image sensor chips are linearly arranged has been put into practical use. Fig. 1 is a block diagram showing an arrangement of a conventional multichip image sensor. Referring to Fig. 1, n light-receiving elements 2-1-1 to 2-1-n are formed in a line in the x direction on a sensor chip 1-1. A circuit 3-1 for sequentially selecting outputs from the light-receiving elements 2-1-1 to 2-1-n is formed on the chip 1-1. An amplifier 4-1 for amplifying an output from the circuit 3-1 is also formed on the chip 1-1. An output from the amplifier 4-1 is output outside the chip from an output line 5-1 generally via a signal extracting section. The circuit 3-1 is driven by an external driver via an input line 8-1. Sensor chips 1-2 to 1-m have the same arrangement as that of the sensor chip 1-1. In the sensor chips 1-2 to 1-m, therefore, the same reference numerals as in the sensor chip 1-1 denote the same parts. The sensor chips 1-1 to 1-m are arranged in a line in the x direction. Therefore, a total of (n x m) light-receiving elements are arranged in a line in the x direction. Upon image reading, an original carrying an image to be read and/or a photoelectric conversion apparatus are conveyed in the y direction relative to each other so that the original faces the light-receiving elements. Outputs from all light-receiving elements of the chip 1-1 are sequentially selected by the circuit 3-1 and externally output from the output line 5-1. Outputs from all light-receiving elements of the chip 1-2 are then sequentially selected by a circuit 3-2 and externally output from an output line 5-2. Subsequently, signals from the-light-receiving elements of other chips are similarly, read sequentially. As a result, outputs from all light-receiving elements are time-serially output. In the conventional multichip image sensor as described above, since an output signal from each sensor chip is independently extracted to an external signal processor, the number of signal lines is increased to complicate the wiring. In order to solve this problem, a common signal line may be used to extract signals to the external signal processor. If, however, all sensor chips including those not externally outputting signals from light-receiving elements are connected to the output line, crosstalk between signals occurs and the S/N ratio of the signal is reduced. In addition, in the above conventional multichip image sensor, an amplifier is in an operative state even while light-emitting elements of each chip do not externally output signals. For this reason, if the number of sensor chips is increased, unnecessary consumption power is increased or heat is generated to increase the chip temperature, thereby degrading the sensor characteristics. United Kingdom Patent Application GB-A-2160058 discloses a photoelectric conversion apparatus in which light receiving elements are arranged in blocks, these elements are selected sequentially and the output signals from each block are output via a respective block output signal bias. The block output signal lines of alternate blocks in a line array are connected to a respective alternate output amplifier via a respective array of switches. The switches are operated so that the serial output of each block is selected in turn. The output of each output amplifier is selected alternatively by output switches. A delay is provided between the operation of switches on the input side of the amplifiers and sequential selection of the light receiving elements and operation of the output switches. Switching transients are therefore isolated from the output. EP-A-0 292 253 also discloses a photoelectric conversion apparatus in which light receiving elements are arranged in blocks. However, the preamplifier included in each block is controlled by an external controller. SUMMARY OF THE INVENTION The problem of eliminating cross-talk is addressed and a solution is provided without requiring increase in wiring complexity. Sensor chips and multichip photoelectric conversion apparatus in accordance with the present invention are defined in the appended claims. In such sensor chips the output signal from the chip is interrupted by a chip mounted controller operating either a switch on the output side of the chip amplifier or enabling/disabling the chip amplifier. The chip output is interrupted for intervals during which other chips are selected. Cross-talk accordingly is eliminated and a good S/N ratio is achieved. Also the controller is responsive to the selection circuit of the chip and consequently no additional wiring is required for connecting the controller externally. Arrangements in which the chip amplifier is enabled/disabled are preferred since this conserves power and reduces heat generation. Degradation of sensor characteristics, due to temperature rise, is thus prevented. Preferably the enablement of the chip amplifier is advanced to allow time for start and stabilisation prior to sequential selection of the chip light receiving elements. In such case the enablement time intervals for each chip in a photoelectric conversion apparatus are overlapped to reduce read time. The selection circuit may be implemented using a shift register. Advantageously, in photoelectric conversion apparatus, the respective shift registers may be connected. In such case high speed reading may be performed without need for complicated external circuitry. Stages may be added at the front end of each register to introduce delay between amplifier enablement and sequential scan of the light receiving elements. Connections between registers may in such case be taken from a stage preceding the last to avoid delay between successive sequential scans and thus to facilitate high speed reading. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: Fig. 1 is a block diagram showing an arrangement of a conventional multichip image sensor; Fig. 2 is a block diagram showing an arrangement of an embodiment of a photoelectric conversion apparatus according to the present invention; Figs. 3A, 3B and 3C are circuit diagrams showing detailed arrangements of an analog switch; Fig. 4 is a timing chart for explaining an operation of the embodiment shown in Fig. 2; Fig. 5 is a block diagram showing an arrangement of another embodiment of a photoelectric conversion apparatus according to the present invention; Fig. 6 is a timing chart for explaining an operation of the embodiment shown in Fig. 5; Fig. 7 is a timing chart for explaining another operation of the embodiment shown in Fig. 5; Fig. 8 is a block diagram showing another arrangement of a multichip image sensor; Fig. 9 is a timing chart showing operation waveforms of the sensor shown in Fig. 8; Fig. 10 is a block diagram showing yet another arrangement of a multichip image sensor; and Fig. 11 is a timing chart showing operation waveforms of the embodiment shown in Fig. 10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Fig. 2 is a block diagram showing an arrangement of an embodiment of a photoelectric conversion apparatus according to the present invention. Referring to Fig. 2, a sensor chip 1-1 consists of a semiconductor such as silicon. n light-receiving elements 2-1-1 to 2-1-n are formed in a line in the x direction on the chip 1-1. The light-receiving elements are of a type of storing optical pumping carriers in a control electrode region of a transistor and extracting an output corresponding to the stored charge as needed. That is, optical pumping carriers generated upon inputting of optical information are stored in the base region of a transistor to store a charge corresponding to the optical input information, and an output corresponding to the stored charge is extracted as an electrical output signal as needed. In this type, the stored charge can be basically nondestructively read. When the stored charge becomes unnecessary, it is generally discharged by a certain means (not shown). The light-receiving element need not be of this type but may be of another type. A circuit 3-1, including a shift register, for sequentially selecting outputs from the light-receiving elements 2-1-1 to 2-1-m,is formed on the chip 1-1. An amplifier 4-1 for amplifying an output from the circuit 3-1 is formed on the chip 1-1. In this embodiment, an analog switch 6-1 for connecting/disconnecting an output signal line 5-1 of the amplifier 4-1 and a controller 7-1 for controlling a switching operation of the switch are formed on the chip 1-1. The controller 7-1 outputs a control signal on the basis of a signal from the circuit 3-1. The circuit 3-1 is driven by an external driver via an input line 8-1. Figs. 3A, 3B and 3C are circuit diagrams showing detailed alternative arrangements of the analog switch 6-1. Referring to Fig. 3A, passing of a signal Vin as an output from the amplifier 4-1 to Vout is controlled by a control signal c supplied from the controller 7-1 to the gate of an n-type MOS transistor Q 1 . Referring to Fig. 3B, passing of a signal Vin as an output from the amplifier 4-1 to Vout is controlled by a control signal c supplied from the controller 7-1 to the gate of a p-type MOS transistor Q 2 . Referring to Fig. 3C, the sources and the drains of an n-type MOS transistor Q 1 and a p-type MOS transistor Q 2 are commonly connected. A control signal c is directly supplied to the gate of the transistor Q 1 , while it is supplied to the gate of the transistor Q 2 via an inverter, thereby controlling passing of a signal Vin as an output from the amplifier 4-1 to Vout. This arrangement is a C-MOS type gate. Although Figs. 3A to 3C show analog switches using a MOS transistor, an analog switch having the same function can be constituted by using a bipolar transistor. Referring to Fig. 2, sensor chips 1-2 to 1-m have the same arrangement as that of the sensor chip 1-1, and the same reference numerals as in the sensor chip 1-1 denote the same parts in the sensor chips 1-2 to 1-m. Output lines 5-1 to 5-m of the sensor chips are connected to a common signal line 10 outside the chips generally via a signal extracting portion. Thus sensor chips are connected to an external signal processor via this signal line. The sensor chips 1-1 to 1-m are arranged in a line in the x direction. Therefore, a total of (n x m) light-receiving elements are arranged in a line in the x direction. All the sensor chips are arranged and fixed on a substrate (not shown). Upon image reading, an original carrying an image to be read and/or the light-receiving elements are conveyed relative to each other in the y direction so that the original faces the light-receiving elements. An operation of this embodiment will be described below. Fig. 4 is a timing chart for explaining an operation of the above embodiment. Referring to Fig. 4, an output control signal  1 is supplied from the controller 7-1 of the sensor chip 1-1, an output control signal  2 is supplied from the controller 7-2 of the sensor chip 1-2, and outputs Vout 1 and Vout 2 are supplied from the switches 6-1 and 6-2 of the sensor chips 1-1 and 1-2, respectively. The signal  1 is synchronized with an operation of the circuit 3-1 driven by the input line 8-1. That is, the signal  1 is output only for a specific duration, i.e. a time interval in which the outputs from all the light-receiving elements of the chip 1-1 are selected sequentially by the circuit 3-1. Only for this duration, the switch 6-1 is closed, and Vout 1 is output. The output Vout 1 includes the outputs from all the light-receiving elements of the sensor chip 1-1. Similarly, the signal  2 is synchronized with an operation of the circuit 3-2 driven by the input line 8-2. That is, the signal  2 is output only for a specific duration, i.e. a time interval in which outputs from all the light-receiving elements of the chip 1-2 are selected sequentially by the circuit 3-2. Only for this duration, the switch 6-2 is closed, and Vout 2 is output. The output Vout 2 includes the outputs from all the light-receiving elements of the sensor chip 1-2. As shown in Fig. 4, signal  2 starts at the same time as signal  1 ends. Output control signals are similarly generated from the controllers 6-3 to 6-m of the third and subsequent sensor chips 1-3 to 1-m, respectively. As described above, signals are sequentially read from the light-receiving elements, and outputs from the light-receiving elements are time-serially output from the common output line 10. In this embodiment, in each sensor chip, an output from the amplifier is connected to the common output line 10 only for the duration substantially corresponding to the time interval in which signals are output from the light-receiving elements, and is disconnected therefrom for a duration except for the above duration. Therefore, no crosstalk occurs during signal reading to reduce the S/N ratio of the read signal. According to this embodiment, since switching can be automatically set and no wiring is provided for the controller or the switch of each chip from an external driver, an external circuit can be simplified. Another embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Fig. 5 is a block diagram showing an arrangement of another embodiment of a photoelectric conversion apparatus of the present invention. Referring to Fig. 5, a sensor chip 1-1 consists of a semiconductor such as silicon. n light-receiving elements 2-1-1 to 2-1-n are formed in a line in the x direction on the chip. The light-receiving elements are of a type of storing optical pumping carriers in a control electrode region of a transistor and extracting an output corresponding to the stored charge as needed. That is, the type used in the first embodiment is adopted. A circuit 3-1 such as a shift register for sequentially selecting outputs from the light-receiving elements 2-1-1 to 2-1-n is formed on the chip 1-1. An amplifier 4-1 for amplifying an output from the circuit 3-1 is formed on the chip 1-1. An output from the amplifier 4-1 is externally output from an output line 5-1 generally via a signal extracting portion. This output is generally supplied to a signal processor and processed as needed. In the embodiment shown in Figure 5, respective controllers 506-1 to 506-m each for outputting a switching control signal for switching operative and non-operative states of the respective amplifier 4-1 to 4-m are formed on respective chips 1-1 to 1-m. The controllers 506-1 to 506-m are controlled by control signals from circuits 3-1 to 3-m, respectively, of the sensor chips. Sensor chips 1-2 to 1-m have the same arrangement as that of the sensor chip 1-1, and the same reference numerals as in the sensor chip 1-1 denote the same parts in the sensor chips 1-2 to 1-m. The sensor chips 1-1 to 1-m are arranged in a line in the x direction. Therefore, a total of (n x m) light-receiving elements are arranged in a line in the x direction. All the sensor chips are arranged and fixed on a substrate (not shown). Upon image reading, an original carrying an image to be read and/or the photoelectric conversion apparatus are conveyed relative to each other in the y direction so that the original faces the light-receiving elements. In correspondence with a time interval in which an Dperation command signal for sequentially selecting outputs from all the light-receiving elements of each chip is supplied from one of input lines 508-1 to 508-m to a corresponding one of the circuits 3-1 to 3-m, the circuit supplies a signal to the controller, thereby switching operative and non-operative states of the amplifier. The operative and non-operative states of the amplifier are automatically switched, and no external driver having an output for the amplifier need be used. In addition, no wirings need be provided from an external driver to the controllers of the respective chips. Switching between the operative and non-operative states of the amplifier and connection/disconnection of the outputs can be simultaneously performed. In this case, crosstalk and the consumption power can be further reduced. An operation of this embodiment will be described below. Fig. 6 is a timing chart for explaining an operation of the above embodiment. Referring to Fig. 6, an output control signal  501 is supplied from the controller 506-1 of the sensor chip 1-1, an output control signal  502 is supplied from the controller 506-2 of the sensor chip 1-2, and outputs Vout 1 and Vout 2 are supplied from the amplifiers 4-1 and 4-2 of the sensor chips 1-1 and 1-2, respectively. The signal  501 is synchronized with an operation of the circuit 3-1 driven by the input line 508-1. That is, the signal  501 is output only for a specific duration, i.e. a time interval in which outputs from all the light-receiving elements of the chip 1-1 are selected sequentially by the circuit 3-1. Only for this duration, the amplifier 4-1 is operated, and Vout 1 is output. The output Vout 1 includes the outputs from all the light-receiving elements of the sensor chip 1-1. Similarly, the signal  502 is synchronized with an operation of the circuit 3-2 driven by the input line 508-2. That is, the signal  502 is output only for a specific duration, i.e. a time interval in which outputs from all the light-receiving elements of the chip 1-2 are selected sequentially by the circuit 3-2. Only for this duration, the amplifier 4-2 is operated, and Vout 2 is output. The output Vout 2 includes the outputs from all the light-receiving elements of the sensor chip 1-2. As shown in Fig. 6, signal  502 starts at the same time as signal  501 ends. Output control signals are similarly generated from the controllers 506-3 to 506-m of the third and subsequent sensor chips 1-3 to 1-m, respectively. As described above, signals are sequentially read from the light-receiving elements, and outputs from all the light-receiving elements are time-serially output. In this embodiment, in each sensor chip, the amplifier is operated only for the duration substantially corresponding to the time interval in which signals are output from the light-receiving elements and is not operated for a duration except for the above duration. Therefore, consumption power of the amplifiers 4-1 to 4-m is reduced to be 1/m conventional consumption power. Fig. 7 is a timing chart for explaining another operation of the above embodiment. In Fig. 7, the same reference numerals as in Fig. 6 are used. As shown in Fig. 7, a control signal  501 of the first sensor chip and a control signal  502 of the second sensor chip overlap each other by a time t . The signals  501 and  502 are activated slightly before (by the time t ) the first light-receiving element is selected by the selecting circuit in each sensor chip. This also applies to the third and subsequent sensor chips. As described above, the control signal is started slightly before the first light-receiving element of each sensor chip is read. Therefore, a time required for starting and stabilising an operation of each amplifier is assured, and signals from all the light-receiving elements including the first light-receiving element can be stably output with high precision in each sensor chip. In addition, since the overlap time of the control signals is sufficiently short with respect to the total time, the consumption power is not much increased compared with that of the operation shown in Fig. 6. Fig. 8 shows an arrangement of a multichip image sensor using an image sensor chip, and Fig. 9 shows operation waveforms (timing chart) thereof. Referring to Fig. 8, image sensor chips (to be sometimes referred to as merely "chips" hereinafter) 1-1, 1-2, ..., 1-m are connected to constitute a multichip image sensor. Light-receiving elements 2-1-1 to 2-1-n are formed on the image sensor chip 1-1 and convert input light signals into electrical signals. Since the light-receiving elements 2-1-1 to 2-m-n are arranged and connected in this multichip image sensor, the sensor length of this image sensor is long enough to correspond to a large original size. This multichip sensor starts its operation when a start signal is supplied from a start terminal 908 to the first chip 1-1 in synchronism with a clock signal from a clock terminal 909. Upon reception of this start signal, shift register stages 904-1-1 to 904-1-n sequentially turn on MOS switches 903-1-1 to 903-1-n to activate the light-receiving elements 2-1-1 to 2-1-n connected to the MOS switches, thereby reading a light signal. This light signal is amplified by a light signal output amplifier 906-1 and output to an output terminal 907 as an optical output signal. A controller 905-1 switches operative and nonoperative states of a constant current circuit of the light signal output amplifier 906-1. The controller 905-1 activates the constant current circuit substantially at the same time as the first shift register 4-1-1 receives the start signal, thereby activating the light signal output amplifier 906-1. An output from the last shift register 904-1-n of the chip 1-1 turns on the last MOS switch 903-1-n and is externally output to be supplied as a start signal to the first shift register 904-2-1 of the next chip 1-2. In the next chip 1-2, the same operation as in the chip 1-1 described above is performed, and a start signal is output to the next chip 1-3 (not shown). In this manner, the start signal is sequentially output to the next chip to execute a reading operation of a light signal having the sensor length. Fig. 9 shows operation waveforms (timing chart) of the above multichip image sensor. Referring to Fig. 9 a light signal of the light-receiving element 2-2-1 is read a time S after a start signal is output to the chip 1-2. Therefore, the chip 1-2 must activate the constant current circuit of the amplifier within the time S. In addition, since the time S is shortened when a clock frequency is increased, the constant current circuit must be activated within a short time period. As described above, the reading of the light signal from the light-receiving element 2-1-1 upon inputting of the start signal and activation of the constant current circuit of the light signal output amplifier 906-1 are performed at substantially the same time. Therefore, in order to read the light signal after the constant current circuit is completely activated, the frequency of a clock signal must be decreased to sufficiently increase the read time of the light-receiving element per pixel. When the frequency of a clock signal is increased to reduce the read time to achieve high-speed processing, the constant current circuit sometimes cannot be perfectly activated. That is, a light signal from the light-receiving element is output before the light signal output amplifier 906-1 is perfectly set in the operative state, and accurate signal amplification is disabled. In order to solve this problem, the frequency of a clock signal for the first light-receiving element of each chip may be reduced. In this case, however, a complicated circuit must be externally provided to increase the cost. Therefore, even if the frequency of a clock signal is increased in order to reduce the read time of a light signal of the multichip image sensor to achieve high-speed read, this increase is limited by the activation time of the constant current circuit. Still another embodiment in which a constant current circuit of a light signal amplifier is activated beforehand to solve this problem will be described below with reference to the accompanying drawings. This method can be applied to the above embodiment. Fig.10 is a block diagram showing an arrangement of a multichip image sensor as an embodiment of an image sensor chip according to the present invention and a photoelectric conversion apparatus using the same. Referring to Fig. 10 in image sensor chips 1-1, 1-2, ..., 1-m, the same reference numerals as in Fig. 8 denote the same parts. First (from the left in Fig.10 ) shift register stages 904-1-i, 904-1-j, 904-2-i, 904-2-j, ..., 904-m-i, and 904-m-j of the respective chips delay start signals. A sensor operation of the multichip image sensor according to this embodiment is performed as follows. That is, after light signals are stored, a clock signal is supplied from a clock terminal 909 to each chip, and a start signal is supplied from a start terminal 908 to the first chip 1-1. This start signal is supplied to a controller 905-1 via a delay shift register stage 904-1-i. The controller 905-1 turns on a constant current circuit (not shown) of a light signal output amplifier 906-1. As a result, the light signal output amplifier 906-1 is enabled. The start signal is also supplied to the shift register stage 904-1-1 via the delay shift register stage 904-1-j and turns on a light-receiving element switching MOS switch 903-1-1. As a result, a light signal is read from the light-receiving element 2-1-1, amplified by the light signal output amplifier 906-1, and output to an output terminal 907. Subsequently, the light signal read operation is sequentially performed up to the light-receiving element 2-1-n in synchronism with the clock signal via the shift registers. During this read operation to be sequentially executed, an output signal from the shift register 904-1-ℓ is externally output from the chip 1-1 and used as a start signal for the next chip 1-2 at the same time the light-receiving element 2-1-ℓ is read. The start signal received by the next chip 1-2 is supplied to a controller 905-2 via the delay register 904-2-i. As a result, the controller 905-2 turns on a constant current circuit of a light signal output amplifier 906-2 beforehand. Thereafter, in the chip 1-1, shift registers stages 904-1-(ℓ + 1) to 904-1-n are activated by a clock signal to read the remaining light-receiving elements 2-1-(ℓ + 1) to 2-1-n, respectively. At the same time, in the chip 1-2, a read operation for the light-receiving element 2-2-1 is delayed by the delay shift register stages 904-2-i and 904-2-j. This delay operation ends at the same time as the read operation of the chip 1-1 ends. The MOS switch 903-2-1 is turned on by the shift register stage 904-2-1, and reading of a light signal of the light-receiving element 2-2-1 is started. At this time, since a constant current circuit of the light signal output amplifier 906-2 of the chip 1-2 can satisfactorily operate, accurate signal amplification can be executed. In this embodiment as described above, an operation time from the shift registers 904-1-ℓ to 904-1-n of the chip 1-1 and an operation time from the delay shift register stages 904-2-i to 904-2-j of the chip 1-2 are adjusted such that the read operation of the chip 1-2 is started immediately after the read operation of the chip 1-1 is ended. In addition, a time enough for activating the constant current circuit of the chip 1-2 is assured. Fig. 11 shows operation waveforms (timing chart) for explaining the above operation of this embodiment. Referring to Fig. 12, the start signal for the chip 1-2 is output simultaneously with the output signal from the shift register stage 904-1-ℓ of the chip 1-1, thereby activating the constant current circuit of the chip 1-2 (not shown). The start signal is delayed by a time T by the shift register stage 904-2-i and the shift register stage 904-2-j (not shown). Thereafter, the shift registerstage 904-2-1 reads a light signal output from the light-receiving element 2-2-1. Even if the clock frequency is increased, accurate light signal amplification can be performed since the time T is designed to be a time enough for activating the constant current circuit. In this embodiment, the shift registers are arranged in a line in correspondence with the light-receiving elements. The shift registers, however, can be arranged in any place of the chip as long as the wiring can be made.

Claims: A sensor chip for use in a multichip photoelectric conversion apparatus, which sensor chip (1-1;1-2;.;1-m) comprises: an array of light receiving elements (2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ..; 2-m-1 to 2-m-n); an output signal line (5-1; 5-2; ..; 5-m) common to said array of light receiving elements (2-1-1 to 2-1-n); a selection circuit (3-1;3-2; ..; 3-m), for selecting sequentially each of said light receiving elements (2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ..; 2-m-1 to 2-m-n) and for connecting them to said output signal line (5-1; 5-2; ..; 5-4); and an amplifier (4-1; 4-2; ..; 4-m) interposed between said output signal line (5-1; 5-2; ..; 5-m) and said selection circuit (3-1; 3-2; ...; 3-m); which sensor chip is characterised by: a switch (6-1; 6-2; ..; 6-m) interposed between said output signal line (5-1; 5-2; ...; 5-m) and said amplifier (4-1; 4-2; ..; 4-m); and a controller (7-1; 7-2; .., 7-m), which is responsive to said selection circuit (3-1; 3-2; ..; 3-m) and is operable to close said switch (6-1; 6-2; ..; 6-m) only for a time interval during which said light receiving elements (2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ..; 2-m-1 to 2-m-n) are selected sequentially and to open said switch (6-1; 6-2; ..; 6-m) at other times. A sensor chip for use in a multichip photoelectric conversion apparatus, which sensor chip (1-1;1-2;1-m) comprises: an array of light receiving elements (2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ..; 2-m-1 to 2-m-n); an output signal line (5-1; 5-2; ..; 5-m) common to said array of light receiving elements (2-1-1 to 2-1-n); a selection circuit (3-1;3-2; ..; 3-m), for selecting sequentially each of said light receiving elements (2-1-1 to 2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ..; 2-m-1 to 2-m-n) and for connecting them to said output signal line (5-1; 5-2; ..; 5-4); and an amplifier (4-1; 4-2; ..; 4-m) interposed between said output signal line (5-1; 5-2; ..; 5-m) and said selection circuit (3-1; 3-2; ...; 3-m); which sensor chip is characterised by: a controller (506-1; 506-2; ..; 506-m), which is responsive to said selection circuit (3-1; 3-2; ..; 3-m), and is operable to enable said amplifier (4-1; 4-2; ...; 4-m) only for a time interval during which said light receiving elements (2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ..; 2-m-1 to 2-m-n) are selected sequentially and to disable said amplifier (4-1; 4-2; ..; 4-m) at other times. A sensor chip as claimed in claim 2 wherein said controller (7-1; 7-2; ..; 7-m) and said selection circuit (3-1; 3-2; ..; 3-m) co-operate to enable said amplifier (4-1; 4-2; ..; 4-m) in advance of selection of a first one (2-1-1; 2-2-1; ...; 2-m-1) of said light receiving elements (2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ..; 2-m-1 to 2-m-n) by a sufficient time to start and stabilise operation of said amplifier (4-1; 4-2; ...; 4-m). A sensor chip as claimed in claims 2 or 3 wherein said selection circuit (3-1; 3-2; .. 3-m) comprises a shift register (904-1-1 to 904-1-n; 904-2-1 to 904-1-n; ...; 904-m-1 to 904-m-n; 904-1-i, 904-1-j, 904-1-1 to 904-1-n; 904-2-i, 904-2-j, 904-2-1 to 904-2-n; ..; 904-m-i, 904-m-j, 904-m-1 to 904-m-n) for selecting sequentially said light receiving elements (2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ..; 2-m-1 to 2-m-n) and said controller (905-1; 905-2; ..; 905-m) is connected to a stage (904-1-1; 904-2-1; ..; 904-m-1; 904-1-i; 904-2-i; ..; 904-m-i) of said shift register. A sensor chip as claimed in claim 4, depending from claim 2, wherein said controller (905-1; 905-2; ..; 905-m) is connected to that stage (904-1-1; 904-2-1; ..; 904-m-1) of said shift register (904-1-1 to 904-1-n; 904-2-1 to 904-1-n; ...; 904-m-1 to 904-m-n; 904-1-i, 904-1-j, 904-1-1 to 904-1-n; 904-2-i, 904-2-j, 904-2-1 to 904-2-n; ..; 904-m-i, 904-m-j, 904-m-1 to 904-m-n) selecting the first one (2-1-1; 2-2-1; ..; 2-m-n) of said light receiving elements (2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ..; 2-m-1 to 2-m-n). A sensor chip as claimed in claim 4 depending from claim 3, wherein said controller (905-1; 905-2; ..; 905-m) is connected to a stage (904-1-i; 904-2-i; ..; 904-m-i) preceding that stage (904-1-1; 904-2-1; ..; 904-m-1) of said shift register (904-1-i, 9040201; 904-m-n) selecting the first one (2-1-1; 2-2-1; ..; 2-m-n) of said light receiving elements (2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ..; 2-m-1 to 2-m-n). A sensor chip as claimed in any preceding claim wherein each light receiving element (2-1-1 to 2-1-n; 2-2-1 to 2-2-n; ...; 2-m-1 to 2-m-n) has a transistor structure for storing photoexcited carriers in a control electrode region of said transistor structure. A photoelectric conversion apparatus comprising: an array of sensor chips (1-1; 1-2; .., 1-m) each as claimed in any one of the preceding claims; and a common output line (10) connected to the output signal line (5-1, 5-2, ..., 5-m) of each sensor chip (1-1, 1-2, .., 1-m). A photoelectric conversion apparatus as claimed in claim 8 wherein said sensor chips (1-1, 1-2, ..; 1-m) are each as claimed in claim 5 and the last stage (904-1-n, 904-2-n, .., 904-(m-1)-n) of the shift register of each sensor chip (1-1, 1-2, .., 1-(m-1)) is connected to the first stage (904-2-i, 904-3-i, .. 904-n-i) of the next sensor chip (1-2, 1-3, .., 1-m) of said array. A photoelectric conversion apparatus as claimed in claim 8 wherein said sensor chips (1-1, 1-2, ..; 1-m) are each as claimed in claim 6 and a stage (904-1-1, 904-2-1, .., 904-(m-1)-1) preceding the last stage (904-1-n, 904-2-n, .., 904-(m-1)-n) of the shift register of each sensor chip is connected to a stage of the shift register of the next chip preceding the stage connected to the first light receiving element of that next chip of said array.

Inventors: KOIDE YOSHIO, NAKAMURA KENICHI, KOIDE, YOSHIO, NAKAMURA, KENICHI, KOIDE, YOSHIO, CANON DAINI HONATSUGIRYO, NAKAMURA, KENICHI, KOTOBUKIHAITSU 101
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1990
Main classification: H04N1
IPC codes: G11C19, H04N3, H04N1