JP2006074503A - Image sensor, image reader and method for controlling image sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the characteristic of an image sensor as much as possible by simplifying wirings for forming the image sensor as much as possible. <P>SOLUTION: Counters 311a, 312a and 313a are mounted in control circuit parts 311, 312 and 313, the control circuit parts 311, 312 and 313 manage a reading operation of optical signals in photoelectric converters 711a to 711n, 712a to 712n and 713a to 713n on the basis of counted values of the counters 311a, 312a and 313a to thereby be able to start controlling an image sensor chip without outputting signals from shift registers 751, 752 and 753, eliminating the need of long wirings from the shift registers 751, 752 and 753 to the control circuit part 311, 312 and 313. Consequently, an effect on disturbance noise can be reduced as much as possible while reducing a chip size in comparison with a conventional manner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image sensor, an image reading apparatus, and an image sensor control method, and is particularly suitable for use in a multi-chip type image sensor in which a plurality of image sensor chips are arranged.

  Conventionally, linear image sensors have been used as image reading apparatuses such as facsimiles and scanners. Since an image sensor chip used for such a linear image sensor is formed on a silicon wafer, the sensor length is limited by the wafer size, and only a short one is often obtained. For this reason, when an image reading apparatus is constituted by one image sensor chip, the reflected light from the original is reduced by using an optical system and projected onto the image sensor chip to read an image. In the case of using such a reduction optical system image sensor, it is necessary to make a large space in the optical system, which hinders downsizing. In order to solve this problem, there is an image reading apparatus using a multi-chip type image sensor in which a plurality of image sensor chips are linearly arranged.

(First prior art)
As a first conventional technique regarding such a multi-chip type image sensor, those disclosed in Japanese Patent Application Laid-Open No. 2-291050 (Patent Document 1) and Japanese Patent Application Laid-Open No. 6-189065 (Patent Document 2). was there.
FIG. 7 is a diagram showing a configuration of a multi-chip type image sensor using an image sensor chip according to the first prior art. FIG. 8 is a timing chart for explaining the operation of a conventional multi-chip type image sensor.

  In FIG. 7, reference numerals 700a to 700n denote image sensor chips, and the image sensor chips 700a to 700n are connected to each other to form a multichip type image sensor chip. In the image sensor chips 700a to 700n, reference numerals 711 to 713 denote photoelectric conversion units that convert input optical signals into electric signals.

  The multi-chip type image sensor has a large sensor length by arranging a plurality of photoelectric conversion elements 711a to 711n, 712a to 712n, and 713a to 713n in a straight line in the photoelectric conversion units 711 to 713, It is also possible to handle reading of large-size documents.

  The multi-chip image sensor is synchronized with the clock signal CLK from the clock terminal CT, and starts operating when the start signal SS is input from the start terminal ST. In response to the start signal SS, the control circuit unit 721 sets the output circuit unit 731 to an operating state, turns on the output switch 741, and scan signals to set the shift registers 751a to 751n to an operating state. Is sent out.

  When the scanning signal is transmitted from the control circuit unit 721, the shift registers 751a to 751n sequentially turn on the MOS switches 761a to 761n made of CMOS transistors in synchronization with the clock signal CLK, and each of the MOS switches 761a to 761a. The photoelectric conversion elements 711a to 711n connected to 761n are operated to read out an optical signal. This optical signal is amplified by the output circuit unit 731 and output as an optical output signal OS to the output terminal OT via the output switch 741.

  The final-stage shift register 751n in the image sensor chip 700a turns on the MOS switch 761n and sends a signal to the control circuit unit 721. Upon receiving this signal, the control circuit portion 721 outputs a signal for turning off the output circuit portion 731, a signal for turning off the output switch 741, and a signal for turning off the shift registers 751 a to 751 n. Send it out. Simultaneously with this operation, the shift register 751n at the final stage outputs a next signal NS to the image sensor chip 700b via the next terminal 771, and the next image sensor chip 700b inputs the next signal NS as a start signal. .

The image sensor chip 700b also performs the same operation as the image sensor chip 700a described above, and further sends a next signal as a start signal to the next image sensor chip. In this way, the image sensor chips 700a to 700n perform an operation so that an optical signal reading operation is performed.
As described above, in order to suppress current consumption, the multi-chip type image sensor sets only the image sensor chips 700a to 700n that are reading optical signals to the operating state, and sets the other image sensor chips 700a to 700n to the standby state. To. Further, when configuring the image sensor chips 700a to 700n, it is necessary to arrange the photoelectric conversion units 711 to 713 by the sensor length. Then, the long sides of the image sensor chips 700a to 700n are about 8 [mm] to 30 [mm]. The short sides of the image sensor chips 700a to 700n are desirably as small as possible within a range of 1 [mm] or less in order to reduce costs. Thus, since the image sensor chips 700a to 700n are elongated chips, it is important to reduce the circuit size and the number of wirings.

(Second prior art)
As a second prior art, JP 11-234473 A (Patent Document 3) proposes a contact image sensor having a resolution switching function.
FIG. 9 is a diagram showing a configuration of a multi-chip type image sensor using an image sensor chip having a resolution switching function according to the second prior art. In FIG. 9, the same components as those in FIG. 7 are denoted by the same reference numerals as those in FIG.

  In the second conventional technique described in Patent Document 3, two or more resolution modes that can be switched are provided, and a predetermined voltage is applied to the resolution selection terminal KT to select the resolution mode, so that the shift registers 751, 752, The resolution switching is realized by changing the path of the scanning signal 753 and changing the path of the signal output to the MOS switches 761, 762, and 763 for reading out the optical signal.

  In this case, the shift registers 751n and 752n that supply start signals to the next image sensor chips 900b and 900c differ depending on the resolution mode. Therefore, signal lines are provided from the respective shift registers 751, 752, and 753 for each resolution mode, and start signals (next signals) output to the next image sensor chips 900b and 900n by the next signal switching units 911, 912, and 913 are provided. The signal NS) is switched for each resolution so that the optical signal OS is continuously output even at the joints of the image sensor chips 900a to 900n.

(Third prior art)
In the third technique described in Japanese Patent Laid-Open No. Hei 3-192868 (Patent Document 4), in order to reduce the number of shift registers for scanning optical signal readout, a shift register and a binary counter are provided. A combined contact image sensor has been proposed. In such a contact image sensor, the number of elements can be reduced, but the chip size may not necessarily be reduced due to an increase in wiring.

JP-A-2-210950 Japanese Patent Laid-Open No. 6-189065 JP 11-234473 A Japanese Patent Laid-Open No. 3-192868

  As described above, in the conventional technique, the image sensor chip is controlled using a signal from the shift register. The control circuit unit sends a signal to the head of the shift register and receives a signal from the shift register at the final stage to generate a control signal for the image sensor chip. Therefore, the wiring from the shift register to the control circuit unit is very long. For this reason, this wiring has a problem in that it affects the length of the short side of the image sensor chip, and is easily affected by signal delay due to parasitic components of the wiring, disturbance noise, and the like.

  The present invention has been made in view of the above-described problems, and an object thereof is to simplify the wiring for forming the image sensor as much as possible and improve the characteristics of the image sensor as much as possible.

An image sensor according to the present invention reads a light signal based on image information and photoelectrically converts it into an electrical signal, scanning means for sequentially scanning the plurality of photoelectric conversion means, and scanning by the scanning means An image having amplification output means for amplifying and outputting an electrical signal photoelectrically converted by the photoelectric conversion means, and control means for controlling the optical signal reading operation and the operation of the amplification output means in the plurality of photoelectric conversion means. A multi-chip type image sensor comprising a plurality of sensor chips, wherein the control means counts clock signals and, based on the count value of the clock signals, reads out optical signals in the photoelectric conversion means. It is characterized by controlling.
An image reading apparatus according to the present invention includes the image sensor described above and an image reading unit that reads the image information based on an output from the amplification output unit provided in the image sensor.

  According to the image sensor control method of the present invention, a plurality of photoelectric conversion units that read out an optical signal based on image information and photoelectrically convert it into an electrical signal, a scanning unit that sequentially scans the plurality of photoelectric conversion units, and a scanning unit. An image sensor control method comprising a plurality of image sensor chips each having an amplification output means for amplifying an electric signal photoelectrically converted by a scanned photoelectric conversion means, and reading out an optical signal in the photoelectric conversion means It has a control step of controlling the operation based on the count value of the clock signal.

  According to the present invention, the control means for controlling the reading operation of the optical signal in the plurality of photoelectric conversion means scanned sequentially and the operation of the amplification output means for amplifying the electric signal photoelectrically converted by the plurality of photoelectric conversion means. However, since the optical signal reading operation in the photoelectric conversion unit is controlled based on the count value of the clock signal, the control unit obtains a signal from the scanning unit that sequentially scans the plurality of photoelectric conversion units. Without it, the image sensor chip can be controlled. This eliminates the need for a long wiring from the scanning means to the control means. Thereby, the influence of disturbance noise can be reduced while reducing the size of the image sensor chip as much as possible.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to the drawings.
(Original image reading device)
FIG. 1 is a diagram illustrating an example of a configuration of a document image reading apparatus that reads a document image according to the first embodiment of this invention.
The image sensor 1 includes a photodiode (solid-state imaging device) 2, a selfoc lens 3, an LED array 4, and a contact glass 5. Specific contents of the image sensor 1 will be described later.

  The conveyance rollers 6 are arranged in front of and behind the image sensor 1 and are used for arranging documents. The contact sheet 7 is used for bringing a document into contact with the image sensor 1. The control circuit 10 processes the signal output from the image sensor 1.

  The document detection lever 8 is a lever for detecting that a document is inserted. Specifically, the document detection lever 8 tilts when it detects that a document has been inserted. As a result, the output of the document detection sensor 9 changes. Then, the changed output of the document detection sensor 9 is transmitted to the CPU 215 (see FIG. 2) in the control circuit 10, and the CPU 215 determines that the document is inserted and is disposed on the document transport roller 6. A driving motor (not shown) is driven to start document conveyance and perform a reading operation.

FIG. 2 is a block diagram showing in detail the configuration of the control circuit 10 provided in the document image reading apparatus shown in FIG.
In FIG. 2, the image sensor 1 shown in FIG. 1 is integrally provided with LEDs 202 of respective colors R (red), G (green), and B (blue) as light sources. Then, while conveying the document on the contact glass 5 of the image sensor 1, the LED control (drive) circuit 203 switches on the LEDs 202 for each color R, G, B for each line. By doing so, it is possible to read R, G, B line sequential color image signals.

  The amplifier (AMP) 204 is an amplifier that amplifies the color image signal output from the image sensor 1. The A / D converter 205 performs A / D conversion on the color image signal amplified by the amplifier 204 and outputs, for example, an 8-bit digital image signal. The shading RAM 206 stores shading correction data read in advance from a calibration sheet.

  The shading correction circuit 207 performs shading correction on the image signal output from the A / D converter 205 based on the shading correction data stored in the shading RAM 206. The peak detection circuit 208 is a circuit that detects, for each line, a peak value in the image data that has been subjected to the shading correction by the shading correction circuit 207, and is used to detect the leading edge of the document.

The gamma conversion circuit 209 performs gamma conversion on the image data subjected to the shading correction by the shading correction circuit 207 in accordance with a gun marker set in advance by the host computer.
The buffer RAM 210 is a RAM for temporarily storing image data in order to match the timing of actual reading operation and communication with the host computer. The packing / buffer RAM control circuit 211 performs a packing process according to an image output mode (binary, 4-bit multi-value, 8-bit multi-value, 24-bit multi-value) set in advance by the host computer using the gamma conversion circuit 209. This is performed on image data that has been subjected to gamma conversion. Thereafter, the packing / buffer RAM control circuit 211 writes the image data subjected to the packing processing into the buffer RAM 210. Then, the image data is read from the buffer RAM 210 and output to the interface circuit 212.

  The interface circuit 212 receives control signals and outputs image signals to and from an external device 213 such as a personal computer that serves as a host device of the document image reading apparatus according to the present embodiment.

For example, the CPU 215 constituting the microcomputer includes a ROM 215A storing a processing procedure in the document image reading apparatus and a working RAM 215B, and controls each unit according to the processing procedure stored in the ROM 215A.
The timing signal generation 214 divides the output from an oscillator (OSC) 216 such as a crystal oscillator in accordance with the setting of the CPU 215, and generates various timing signals serving as a reference for operation. The external device 213 is connected to the control circuit 10 via the interface circuit 212. As described above, an example of the external device 213 includes a personal computer.

(Image sensor)
The image sensor 1 disposed in the document image reading apparatus configured as described above will be described. FIG. 3 is a diagram showing an example of the configuration of a multi-chip type image sensor according to the first embodiment of the present invention. In FIG. 3, the same components as those in FIG. 7 are denoted by the same reference numerals as those in FIG.
In FIG. 3, image sensor chips 300a to 300n are connected to each other on a mounting substrate to constitute a multi-chip type image sensor chip. In the image sensor chip 300a, the photoelectric conversion elements 711a to 711n convert the input optical signal into an electrical signal.
The image sensor 1 of the present embodiment is a multi-chip type, and is synchronized with the clock signal CLK from the clock terminal CT, and starts to operate when the start signal SS is input from the start terminal ST.

  In response to the start signal SS, the control circuit unit 311 starts counting the clock signal CLK by the counter 311a mounted in the control circuit unit 311. At the same time as the counting of the clock signal CLK is started, the control circuit unit 311 operates a signal for turning on the output switch unit 741, a signal for turning on the output switch 741, and the shift registers 751a to 751n. A scanning signal for setting the state is transmitted.

When the scanning signal is transmitted from the control circuit unit 311, the shift registers 751a to 751n sequentially turn on (ON (scan)) the MOS switches 761a to 761n in synchronization with the clock signal CLK, and the MOS switches 761a to 761n. The photoelectric conversion elements 711a to 711n connected to are operated to read out optical signals. This optical signal is amplified by the output circuit unit 731 and output as an optical output signal OS to the output terminal OT via the output switch 741.
Further, the counter 311a counts the number of clocks in synchronization with the clock signal CLK, and counts how many bits of photoelectric conversion elements 711a to 711n are read out.

When the counter 311a counts the number of photoelectric conversion elements 711a to 711n arranged in the image sensor chip 300a, that is, when the reading of the last bit of the image sensor chip 300a is completed, the optical signal is read from the counter 311a. Send an end signal. In response to this, the control circuit unit 311 sends a signal for setting the output circuit unit 731 to a non-operation state, a signal for turning off the output switch 741, and a signal for setting the shift registers 751a to 751n to a non-operation state. To do. Note that in the above, the non-operating state refers to a standby state in which power consumption is smaller than an operating state in which an optical signal reading operation or the like is performed.
Simultaneously with this operation, the control circuit unit 311 outputs the next signal NS to the image sensor chip 300b via the next terminal 771, and the next image sensor chip 300b inputs the next signal NS as a start signal.

  The image sensor chip 300b also performs the same operation as the image sensor chip 300a described above, and further sends a next signal as a start signal to the next image sensor chip. In this way, the image sensor chips 300a to 300n perform an operation so that an optical signal reading operation is performed.

  As described above, in this embodiment, the counters 311a, 312a, and 313a are mounted in the control circuit units 311, 312, and 313, and the control circuit units 311, 312, and 313 are based on the count values of the counters 311a, 312a, and 313a. Thus, since the optical signal reading operation in the photoelectric conversion elements 711a to 711n, 712a to 712n, and 713a to 713n is controlled, the image sensor chip 300 can be used without outputting signals from the shift registers 751, 752, and 753. Control can be started. This eliminates the need for long wiring from the shift registers 751, 752, and 753 to the control circuit units 311, 312, and 313. Therefore, it is possible to reduce the influence of disturbance noise as much as possible while reducing the chip size as compared with the prior art.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. Note that this embodiment is different from the first embodiment described above in part of the configuration of the image sensor. Therefore, in the following description, the same components as those in the first embodiment described above and the prior art are denoted by the same reference numerals as those in FIGS. 1 to 3 and FIG. Is omitted.

FIG. 4 is a diagram illustrating an example of the configuration of a multi-chip type image sensor according to the second embodiment of the present invention. FIG. 5 is a timing chart for explaining an example of the operation of the multichip image sensor of the present embodiment.
In FIG. 4, image sensor chips 400a to 400n are connected to each other to form a multi-chip type image sensor chip. The pre-shift registers 411, 412, and 413 are shift registers for delaying scanning signals input to the shift registers 751, 752, and 753 that scan the MOS switches 761, 762, and 763.

The multi-chip type image sensor of this embodiment is synchronized with the clock signal CLK from the clock terminal CT, and starts operating when the start signal SS is input from the start terminal ST.
In response to the start signal SS, the control circuit unit 311 starts counting the clock signal CLK by the counter 311a mounted in the control circuit unit 311. At the same time as the counting of the clock signal CLK is started, the control circuit unit 311 sends out a signal for setting the output circuit unit 731 to an operating state and a scanning signal for setting the shift registers 751a to 751n to an operating state.

When a scanning signal is sent from the control circuit unit 311, the preshift register 411 operates and is delayed by the number of stages of the preshift register 411, and then the scanning signal is input to the shift register 751 a. At the same time as the scanning signal is input to the shift register 751a, a signal for turning on the output switch 741 is sent from the control circuit unit 311. As a result, the image sensor chip 400a can be output. The shift registers 751a to 751n sequentially turn on the MOS switches 761a to 761n in synchronization with the clock signal CLK, and operate the photoelectric conversion elements 711a to 711n connected to the MOS switches 761a to 761n to perform light. Read the signal. This optical signal is amplified by the output circuit unit 731 and output as an optical output signal OS to the output terminal OT via the output switch 741.
In addition, the counter 311a counts the number of clocks in synchronization with the clock signal CLK, and counts what bits of the photoelectric conversion elements 711a to 711n are read out.

  If the number of stages of the pre-shift register 411 is 6, the next signal NS as the start signal is input to the next image sensor chip 400b simultaneously with the output of the previous seven photoelectric conversion elements from the last photoelectric conversion element 711n. By doing so, the optical output signal OS can be continuously obtained even at the joint of the image sensor chip.

  When the counter 311a counts the number of photoelectric conversion elements 711a to 711n arranged in the image sensor chip 400a, that is, when the reading of the last bit of the image sensor chip 400a is completed, the optical signal is read from the counter 11a. Send an end signal. In response to this, the control circuit unit 311 sends a signal for setting the output circuit unit 731 to a non-operation state, a signal for turning off the output switch 741, and a signal for setting the shift registers 751a to 751n to a non-operation state. To do.

  The image sensor chip 400b also performs the same operation as the image sensor chip 400a described above, and further sends a next signal as a start signal to the next image sensor chip. In this way, the image sensor chips 400a to 400n perform an operation so that an optical signal reading operation is performed.

  As described above, in this embodiment, the pre-shift registers 411, 412, and 413 delay the scanning signals input to the shift registers 751, 752, and 753 that scan the MOS switches 761, 762, and 763. The time required to put the output circuit portions 731, 732, and 733 into the operating state can be taken before outputting the optical output signal OS. Accordingly, a more accurate optical output signal OS can be continuously obtained at a high speed at the joint between the image sensor chips 400a to 400n.

  Similarly to the first embodiment described above, since the counters 311a, 312a, and 313a are mounted in the control circuit units 311, 312, and 313, the influence on disturbance noise can be reduced while reducing the chip size. As much as possible.

  In the present embodiment, the pre-shift registers 411, 412, and 413 are provided so as to secure the time necessary for putting the output circuit units 731 732, and 733 into the operating state before outputting the optical output signal OS. However, this is not always necessary. For example, the counters 311a, 312a, and 313a count the total number of the photoelectric conversion elements 711, 712, and 713 and the number of stages of the preshift registers 411, 412, and 413, thereby calculating the preshift registers 411, 412, and 313a. The functions of 413 can be shared by the counters 311a, 312a, and 313a. In this way, the circuit size can be further reduced.

(Third embodiment)
Next, a third embodiment of the present invention will be described. The present embodiment is different from the first and second embodiments described above in part of the configuration of the image sensor. Therefore, in the following description, the same reference numerals as those in FIGS. 1 to 5 and FIG. 7 are assigned to the same components as those in the first and second embodiments described above and the prior art. Detailed description is omitted.

FIG. 6 is a diagram illustrating an example of the configuration of a multi-chip type image sensor according to the third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same structural member as FIG.
In FIG. 6, image sensor chips 600a to 600n are connected to each other to form a multi-chip type image sensor chip. The pre-shift registers 411, 412, and 413 are shift registers for delaying scanning signals input to the shift registers 751, 752, and 753 that scan the MOS switches 761, 762, and 763.

  Further, in this embodiment, by applying a predetermined voltage to the resolution selection terminal KT and selecting a resolution mode, the scanning signal path of the shift registers 751, 752, and 753 is changed, and the MOS switch 761 that reads an optical signal is read. , 762, and 763 to change the path of the signal to realize resolution switching.

  In this case, the timing for supplying the next signal NS as the start signal to the next image sensor chips 600b and 600n differs depending on the resolution mode. For this reason, the next signal switching units 611, 612, and 613 in the control circuit units 601, 602, and 603 switch the start signal (next signal NS) output to the next image sensor chip 600b and 600n for each resolution. The output signal OS is continuously output even at the joint between the image sensor chips 600a to 600n.

  Temporarily, 468 photoelectric conversion elements 711, 712, and 713 are provided in each of the image sensor chips 600a, 600b, and 600n, and the photoelectric conversion elements 711 that are seven preceding the photoelectric conversion elements 711n, 712n, and 713n in the final stage are provided. When the next signal NS is sent to the next image sensor chip 600b, 600n at the same time as the output of, the optical signal output in the 462st photoelectric conversion element 711 is obtained when the normal optical signal read operation is performed. At the same time, the next signal NS is transmitted. On the other hand, when the optical signal is read out with half the resolution, the next signal switching units 611, 612, and 613 are configured to transmit the next signal NS simultaneously with the output of the optical signal from the 228th photoelectric conversion element 711.

  As described above, in the present embodiment, the shift registers that scan the MOS switches 761, 762, and 763 by the pre-shift registers 411, 412, and 413 for the image sensor chips 600a, 600b, and 600n having a plurality of switchable resolution modes. Since the scanning signals input to 751, 752, and 753 are delayed, it is necessary to take a time required to put the output circuit units 731, 732, and 733 into an operating state before outputting the optical output signal OS. it can. As a result, a more accurate optical signal output OS can be continuously obtained at high speed even at the joints between the image sensor chips 600a to 600n having a plurality of switchable resolution modes.

Further, as in the first and second embodiments described above, the counters 311a, 312a, and 313a are mounted in the control circuit units 311, 312, and 313. Therefore, the chip size can be reduced and disturbance noise can be reduced. The influence can be reduced as much as possible.
Furthermore, as described in the second embodiment, the counters 311a, 312a, and 313a are obtained by adding the number of photoelectric conversion elements 711, 712, and 713 and the number of stages of the pre-shift registers 411, 412, and 413, respectively. By counting in step (a), the circuit size can be further reduced so that the functions of the pre-shift registers 411, 412, and 413 are shared by the counters 311a, 312a, and 313a.

(Other embodiments of the present invention)
In order to operate various devices to realize the functions of the above-described embodiments, program codes of software for realizing the functions of the above-described embodiments are provided to an apparatus or a computer in the system connected to the various devices. What is implemented by operating the various devices according to a program supplied and stored in a computer (CPU or MPU) of the system or apparatus is also included in the scope of the present invention.

  In this case, the program code of the software itself realizes the functions of the above-described embodiments, and the program code itself and means for supplying the program code to the computer, for example, the program code are stored. The recorded medium constitutes the present invention. As a recording medium for storing the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, by executing the program code supplied by the computer, not only the functions of the above-described embodiments are realized, but also the OS (operating system) or other application software in which the program code is running on the computer, etc. It goes without saying that the program code is also included in the embodiment of the present invention even when the functions of the above-described embodiment are realized in cooperation with the embodiment.

  Further, after the supplied program code is stored in the memory provided in the function expansion board of the computer or the function expansion unit connected to the computer, the CPU provided in the function expansion board or function expansion unit based on the instruction of the program code Needless to say, the present invention also includes a case where the functions of the above-described embodiment are realized by performing part or all of the actual processing.

1 is a diagram illustrating an example of a configuration of a document image reading apparatus according to a first embodiment of this invention. 1 is a block diagram illustrating in detail a configuration of a control circuit provided in a document image reading apparatus according to a first exemplary embodiment of the present invention. FIG. 1 is a diagram illustrating an example of a configuration of a multichip image sensor according to a first embodiment of the present invention. It is the figure which showed the 2nd Embodiment of this invention and showed an example of the structure of a multichip type image sensor. 6 is a timing chart illustrating an example of the operation of the multichip image sensor according to the second embodiment of this invention. It is the figure which showed the 3rd Embodiment of this invention and showed an example of the structure of a multichip type image sensor. It is the figure which showed the 1st prior art and showed the structure of the multichip type image sensor using an image sensor chip. It is a timing chart which shows the 1st prior art and explains operation of a multichip type image sensor. It is the figure which showed the 2nd prior art and showed the structure of the multichip type image sensor using the image sensor chip which has the switching function of resolution.

Explanation of symbols

1 Image sensor 10 Control circuit 300, 400, 600 Image sensor chips 311 to 313, 601 to 603 Control circuit units 311a to 313a Counters 411 to 413 Preshift registers 611 to 613 Next signal switching units 711 to 713 Photoelectric conversion units 731 to 733 Output circuit units 741 to 743 Output switches 751 to 753 Shift registers 761 to 763 MOS switches 771 to 773 Next terminal CT Clock signal input terminal KT Resolution selection terminal OT Optical signal output terminal ST Start signal input terminal

Claims (12)

A plurality of photoelectric conversion means for reading out an optical signal based on image information and photoelectrically converting it into an electrical signal;
Scanning means for sequentially scanning the plurality of photoelectric conversion means;
Amplifying output means for amplifying and outputting the electrical signal photoelectrically converted by the photoelectric conversion means scanned by the scanning means;
A multi-chip type image sensor comprising a plurality of image sensor chips each having a control means for controlling an optical signal read-out operation and an operation of the amplification output means in the plurality of photoelectric conversion means,
The image sensor according to claim 1, wherein the control unit counts a clock signal and controls a reading operation of the optical signal in the photoelectric conversion unit based on a count value of the clock signal. The plurality of photoelectric conversion means are arranged one-dimensionally,
The image sensor according to claim 1, wherein the plurality of image sensor chips are arranged in the same direction as an arrangement direction of the plurality of photoelectric conversion units.   The control means sets the image sensor chip that reads the optical signal to the operating state based on the count value of the clock signal, and sets the other image sensor chips to a standby state that consumes less current than the operating state. The image sensor according to claim 1, wherein the image sensor is an image sensor.   The plurality of image sensor chips include a delay unit that delays a scanning signal generated by the control unit and outputs the delayed signal to the scanning unit in order to start an optical signal reading operation in the plurality of photoelectric conversion units. The image sensor according to any one of claims 1 to 3, wherein   The control means determines whether or not the optical signal reading operation in the plurality of photoelectric conversion means is completed based on the count value of the clock signal, and the optical signal reading operation in the photoelectric conversion means is completed. 5. The image sensor according to claim 1, wherein a start instruction is issued to an image sensor chip arranged in a next stage.   The plurality of image sensor chips have two or more resolution modes, and according to the resolution modes, the image sensor chips have switching means for switching a timing for giving a start instruction to an image sensor chip arranged in the next stage. The image sensor according to any one of claims 1 to 5. The image sensor according to any one of claims 1 to 6,
An image reading apparatus comprising: an image reading unit that reads the image information based on an output from the amplification output unit provided in the image sensor. A plurality of photoelectric conversion means for reading out an optical signal based on image information and photoelectrically converting it into an electrical signal;
Scanning means for sequentially scanning the plurality of photoelectric conversion means;
An image sensor control method comprising a plurality of image sensor chips each having an amplification output means for amplifying an electrical signal photoelectrically converted by the photoelectric conversion means scanned by the scanning means,
An image sensor control method comprising: a control step of controlling an optical signal reading operation in the photoelectric conversion means based on a count value of a clock signal.   In the control step, based on the count value of the clock signal, the image sensor chip that reads the optical signal is set in an operating state, and the other image sensor chips are set in a standby state in which current consumption is smaller than that in the operating state. The method of controlling an image sensor according to claim 8. A scanning signal generation step of generating a scanning signal for starting an optical signal reading operation in the plurality of photoelectric conversion units;
A scanning signal output step of delaying the scanning signal generated by the scanning signal generation step and outputting it to the scanning means;
The control step controls the reading operation of the optical signal in the photoelectric conversion unit scanned by the scanning unit from which the scanning signal is output in the scanning signal output step based on the count value of the clock signal. Item 10. The image sensor control method according to Item 8 or 9.   In the control step, based on the count value of the clock signal, it is determined whether the optical signal reading operation in the plurality of photoelectric conversion units is completed, and the optical signal reading operation in the photoelectric conversion unit is completed. 11. The image sensor control method according to claim 8, wherein a start instruction is issued to an image sensor chip arranged in the next stage. 11. A resolution mode selection step of selecting a resolution mode in the plurality of image sensor chips;
11. The control step according to claim 8, wherein the timing for performing an activation instruction to the image sensor chip arranged in the next stage is switched according to the resolution mode selected in the resolution mode selection step. The image sensor control method according to claim 1.

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