JP4692160B2 - Photoelectric conversion element inspection method, image reading apparatus, and program - Google Patents

Description

  The present invention relates to a photoelectric conversion element inspection method, an image reading apparatus, and a program.

  Image reading apparatuses such as copying machines, facsimile machines, and scanners are provided with an image sensor for reading an image from a document. This image sensor includes a photoelectric conversion element formed of a photodiode or the like. A charge corresponding to the amount of received light is generated in the photoelectric conversion element. The image sensor reads an image from a document by detecting the amount of charge generated in the photoelectric conversion element in this way.

  By the way, in such an image sensor, the following problems may occur. That is, when the generated charge is moved from the photoelectric conversion element to a predetermined charge storage unit in order to detect the amount of charge generated in the photoelectric conversion element, a part of the charge generated in the photoelectric conversion element is In some cases, the photoelectric conversion element remains in the photoelectric conversion element, so that all charges may not move to the charge storage unit. This defect is also called a linearity defect. When such a linearity defect occurs, the image cannot be read properly from the original, and for this reason, for example, a defect such as a vertical stripe occurs in the read image, which greatly affects the image quality. Problem has occurred.

Therefore, conventionally, various countermeasures have been proposed for such linearity defects (see Patent Document 1 or 2).
Japanese Patent Laid-Open No. 10-276305 JP-A-10-276368

However, a conventionally proposed method has not been proposed for inspecting whether or not each of the plurality of photoelectric conversion elements provided in the image sensor is linearly defective very easily.
The present invention has been made in view of such circumstances, and an object of the present invention is to enable easy inspection of whether or not a photoelectric conversion element is defective.

The main invention for achieving the object is as follows:
Applying light to the photoelectric conversion element to generate charges in the photoelectric conversion element;
In order to move the charge generated in the photoelectric conversion element from the photoelectric conversion element to a charge storage unit, a gate provided between the photoelectric conversion element and the charge storage unit is used to display an image by the photoelectric conversion element. A step of opening only for a shorter time than a predetermined time of opening when performing the reading operation;
The amount of charge transferred to the charge storage unit by opening the gate for the short time, and the amount of charge transferred to the charge storage unit by opening the gate for the predetermined time. Detecting the amount of charge reduced compared to ,
Determining whether or not the photoelectric conversion element is defective based on the detected amount of charge after reduction ;
It is an inspection method of the photoelectric conversion element characterized by having.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

=== Summary of disclosure ===
At least the following matters will become apparent from the description of the present specification and the accompanying drawings.

Applying light to the photoelectric conversion element to generate charges in the photoelectric conversion element;
In order to move the charge generated in the photoelectric conversion element from the photoelectric conversion element to a charge storage unit, a gate provided between the photoelectric conversion element and the charge storage unit is used to display an image by the photoelectric conversion element. A step of opening for a shorter time than when performing a reading operation;
Detecting the amount of charge transferred to the charge storage unit;
Determining whether or not the photoelectric conversion element is defective based on the detected charge amount;
A method for inspecting a photoelectric conversion element, comprising:

  In such a photoelectric conversion element method, the gate provided between the photoelectric conversion element and the charge storage unit is opened for a shorter time than when an operation of reading an image with the photoelectric conversion element is executed. Thus, it can be easily determined whether or not the photoelectric conversion element is defective. Thereby, a test | inspection of a photoelectric conversion element can be implemented efficiently.

  In such a photoelectric conversion element inspection method, the photoelectric conversion element may be a photodiode. Thus, if the photoelectric conversion element is a photodiode, the inspection can be easily performed.

  Further, in such a photoelectric conversion element inspection method, the detected charge amount may be compared with a predetermined value to determine whether or not the photoelectric conversion element is defective. By performing such determination, it can be easily determined whether or not the photoelectric conversion element is defective.

  In addition, the photoelectric conversion element inspection method may further include a step of storing in the memory information related to the photoelectric conversion element determined to be defective. By storing information on the photoelectric conversion element determined to be defective as described above in the memory, it is possible to deal with even if the photoelectric conversion element is defective.

  Further, in the inspection method of the photoelectric conversion element, in order to detect the charge amount of the charge transferred to the charge storage unit, the charge transferred to the charge storage unit is changed to the charge amount of the charge. You may have the step moved to the detection circuit to detect. By having such a step, the charge transferred to the charge storage unit can be easily detected by the detection circuit.

  Further, in such a photoelectric conversion element inspection method, when the electric charge is generated in the photoelectric conversion element, light transmitted through a transmission film having a predetermined transmittance may be applied to the photoelectric conversion element. Thus, by applying the light transmitted through the transmission film having a predetermined transmittance to the photoelectric conversion element, the amount of light applied to the photoelectric conversion element can be easily adjusted.

  Moreover, in this photoelectric conversion element inspection method, a plurality of the photoelectric conversion elements may be provided. Thus, even when there are a plurality of photoelectric conversion elements, each photoelectric conversion element can be easily inspected individually.

  Further, in such a photoelectric conversion element inspection method, the photoelectric conversion element may be three photoelectric conversion elements that respectively receive light of three colors of red, blue, and green. In this way, when the photoelectric conversion elements are three photoelectric conversion elements that respectively receive three colors of light, each photoelectric conversion element can be easily inspected individually.

  In the inspection method of the photoelectric conversion element, when the charge generated in the photoelectric conversion element moves to the charge accumulation unit between the three photoelectric conversion elements and the charge accumulation unit. A register passing therethrough is provided; a first gate is provided as the gate between the register and the three photoelectric conversion elements; and a second gate is provided as the gate between the register and the charge storage unit. The distances between the three photoelectric conversion elements and the charge storage unit may be different from each other. In such a case, it can be easily determined whether or not the photoelectric conversion element is defective.

Applying light to the photoelectric conversion element to generate charges in the photoelectric conversion element;
In order to move the charge generated in the photoelectric conversion element from the photoelectric conversion element to a charge storage unit, a gate provided between the photoelectric conversion element and the charge storage unit is used to display an image by the photoelectric conversion element. A step of opening for a shorter time than when performing a reading operation;
Detecting the amount of charge transferred to the charge storage unit;
Determining whether or not the photoelectric conversion element is defective based on the detected charge amount;
Have
The photoelectric conversion element is a photodiode;
Compare the detected amount of charge with a predetermined value to determine whether the photoelectric conversion element is defective,
Further, a step of storing information on the photoelectric conversion element determined to be defective in a memory, and the charge moved to the charge accumulation unit in order to detect a charge amount of the charge moved to the charge accumulation unit Moving to a detection circuit for detecting a charge amount of the charge,
When generating charges in the photoelectric conversion element, light that has passed through a transmission film of a predetermined transmittance is applied to the photoelectric conversion element,
There are a plurality of the photoelectric conversion elements,
The photoelectric conversion elements are three photoelectric conversion elements that receive light of three colors of red, blue, and green, respectively.
A register through which the charge generated in the photoelectric conversion element moves to the charge storage unit is provided between the three photoelectric conversion elements and the charge storage unit. A first gate is provided as the gate between each of the conversion elements, a second gate is provided as the gate between the register and the charge storage unit, and the three photoelectric conversion elements, the charge storage unit, A method for inspecting a photoelectric conversion element, wherein the distances between the two are different from each other.

It has an image sensor for reading images from the document,
The image sensor includes a photoelectric conversion element that generates a charge by received light, and
A charge accumulating portion to which the charge generated in the photoelectric conversion element moves; and
A gate provided between the photoelectric conversion element and the charge storage unit and opened to move the charge from the photoelectric conversion element to the charge storage unit;
A signal output unit for outputting a first control signal for opening the gate for a predetermined time and a second control signal for opening the gate for a time shorter than the predetermined time;
A charge amount detection unit for detecting a charge amount of the charge moved to the charge storage unit;
An image reading apparatus comprising:

In order to move the charge generated in the photoelectric conversion element by applying light to the photoelectric conversion element from the photoelectric conversion element to the charge storage unit, a gate provided between the photoelectric conversion element and the charge storage unit, Opening for a short time compared to the case of performing an operation of reading an image by the photoelectric conversion element;
Obtaining information on the amount of charge transferred to the charge storage unit;
Determining whether or not the photoelectric conversion element is defective based on the acquired information;
Having a code for causing the image reading apparatus to execute the program.

=== Overview of Image Reading Apparatus ===
The photoelectric conversion element inspection method and the like according to the present invention will be described by taking a composite apparatus which is an image reading apparatus including an image sensor having a photoelectric conversion element as an example. The composite apparatus includes a scanner unit (image reading unit) that reads an image from a document and generates image data, and a printing unit that performs printing on a medium.

  1 to 5 describe an example of a composite apparatus. FIG. 1 is a perspective view showing the external appearance of the composite apparatus 1. FIG. 2 is a perspective view illustrating an outline of the scanner unit 10 of the multifunction apparatus 1. FIG. 3 is a perspective view illustrating an outline of the printer unit of the composite apparatus 1. FIG. 4 is an explanatory diagram schematically illustrating the internal configuration of the composite apparatus 1. FIG. 5 is a plan view for explaining the operation panel 2 of the composite apparatus 1.

  The composite apparatus 1 includes a scanner function that reads an image from a document and generates image data, a printer function that prints on various media such as printing paper based on print data sent from a host computer (not shown), And a local copy function for printing an image read from a document on a medium and copying it. As shown in FIG. 1, the multifunction apparatus 1 includes a scanner unit 10 for reading an image from a document 5 at an upper portion thereof. In addition, a printer unit 30 for printing on a medium S such as printing paper is provided at the lower part of the composite apparatus 1. In addition, an operation panel 2 is provided on the front surface of the composite apparatus 1.

  As shown in FIG. 2, the scanner unit 10 includes a document table 11 provided with a glass plate on which the document 5 is set, and a document table cover 12 that covers the document table 11 from above. The document table cover 12 is rotatably attached to the rear end portion of the multifunction apparatus 1 and is provided so as to open and close the upper surface portion of the document table 11.

  On the other hand, as shown in FIG. 3, the printer unit 30 is configured such that the inside of the printer unit 30 is opened to the outside through the opening 32 by lifting the scanner unit 10 upward. That is, the scanner unit 10 is rotatably attached to the rear part of the multifunction apparatus 1 via the hinge unit 34. When the scanner unit 10 is lifted upward, the opening 32 leading to the inside of the printer unit 30 is opened. Inside the printer unit 30, a carriage 41 for mounting an ink cartridge is disposed. By opening the inside of the printer unit 30 in this way, maintenance work such as replacement of an ink cartridge, error handling such as a paper jam, and the like can be easily performed through the opening 32.

  In addition, the printer unit 30 includes a paper feeding unit 4 on which a medium S such as printing paper is set and sequentially supplies the medium S to the back of the multifunction apparatus 1. In addition, the printer unit 30 includes a paper discharge unit 3 that discharges the printed medium S at the front of the multifunction apparatus 1. The paper feed unit 4 includes a paper feed tray 8. A medium such as printing paper is set in the paper feed tray 8. The paper discharge unit 3 includes a paper discharge tray 7 and receives the medium S that has been printed and discharged. The medium S set in the paper feeding unit 4 may be not only single-sheet printing paper such as cut paper but also continuous printing paper such as roll paper. A corresponding structure may be provided.

=== Internal Mechanism of Scanner Unit 10 and Printer Unit 30 ===
FIG. 4 shows the internal mechanism of the scanner unit 10 and the printer unit 30.

<Scanner part>
As shown in the upper part of the figure, the scanner unit 10 has a scanner carriage 60 below the document table 11 and an arrow A in the figure while keeping the scanner carriage 60 at a predetermined distance from the document table 11. A driving mechanism 62 that moves in parallel along the direction and a guide 64 that supports the scanner carriage 60 and guides its movement are provided.

  The scanner carriage 60 has an exposure lamp 66 as a light source for irradiating light to the document 5 through the document table 11, a lens 70A on which reflected light reflected by the document 5 is incident, and the scanner 70 through the lens 70A. An image sensor 72A that receives the reflected light taken into the carriage 60 is provided. Furthermore, in this embodiment, in addition to the lens 70A and the image sensor 72A, an image sensor 72B and a lens 70B for reading an image from a film as a document are provided.

  In the present embodiment, these image sensors 72A and 72B are configured by linear CCD sensors in which photoelectric conversion elements such as photodiodes that convert optical signals into electric signals are arranged in a line. The image sensors 72A and 72B are contact image sensors (CIS image sensors: Contact Image Sensors), and their width dimensions are set corresponding to the size of the original to be read. That is, the image sensors 72A and 72B can read the image of the document 5 set on the document table 11 at the same magnification. The image data read by the image sensors 72A and 72B is output to the control unit 50.

  The drive mechanism 62 includes a timing belt 74 connected to the scanner carriage 60, a pair of pulleys 75 and 76 around which the timing belt 74 is stretched, and a drive motor 77 that rotationally drives one pulley 75. I have. The drive motor 77 is driven and controlled by a control signal from the control unit 50.

<Printer section>
On the other hand, the printer unit 30 holds the printer carriage 41, the head 21 mounted on the printer carriage 41, and the printer carriage 41 at a predetermined distance from the medium S as shown in the lower part of FIG. 4. However, a drive mechanism 24 that moves relatively parallel to each other and a transport mechanism 36 that transports the medium S along a direction orthogonal to the moving direction of the printer carriage 41 are provided.

  The printer carriage 41 is provided with a cartridge mounting portion, and an ink cartridge containing black (K), cyan (C), magenta (M), yellow (Y) or the like ink is stored in the cartridge mounting portion. Installed.

  The head 21 discharges ink of each color supplied from the ink cartridge toward the medium S to form dots on the medium S, and prints an image on the medium S.

  The drive mechanism 24 includes a timing belt 45 connected to the printer carriage 41, a pulley 44 meshed with the timing belt 45, a carriage motor 42 (hereinafter also referred to as a CR motor) that rotationally drives the pulley 44, and A guide rail 46 that guides the movement of the printer carriage 41, a linear encoder code plate 51 as a linear encoder that detects the position of the printer carriage 41, and a detection unit 52 that reads the linear encoder code plate 51 are provided. Yes. The drive mechanism 24 drives the carriage motor 42 to rotate the timing belt 45 via the pulley 44. As a result, the printer carriage 41 moves relative to the medium S along the guide rail 46. The carriage motor 42 is driven and controlled by a control signal from the control unit 50.

  The transport mechanism 36 includes a platen 14, a transport roller 17A, a transport motor 15 that rotationally drives the transport roller 17A, a paper detection sensor 53 that detects whether the medium S has reached a predetermined position, and the transport roller 17A. And a rotary encoder 56 for detecting the amount of rotation. The platen 14 is disposed to face the head 21. When the transport motor 15 is driven, the transport roller 17 </ b> A rotates and the medium S is transported on the platen 14. The conveyance motor 15 is driven and controlled by a control signal from the control unit 50.

  At the time of printing, the medium S is intermittently transported by a predetermined transport amount by the transport roller 17A, and the printer carriage 41 is along the direction intersecting the transport direction by the transport roller 17A between the intermittent transports. While moving, ink is ejected from the head 21 toward the medium S to perform printing.

=== Operation panel ===
FIG. 5 shows the operation panel 2 of the composite apparatus 1. The operation panel 2 includes a liquid crystal display 80 at substantially the center thereof. The liquid crystal display 80 can display characters and images. The display content of the liquid crystal display 80 changes according to the setting item, the setting state, the operation state, and the like.

  On the left side of the liquid crystal display 80, a notification lamp 81, a power button 82, various setting buttons 83, mode buttons 84, 85, 86, 87, and a paper supply / discharge button 88 are provided. The notification lamp 81 is a red LED and lights up when an error occurs to notify the user of the occurrence of the error. The power button 82 is a button for turning on / off the power of the composite apparatus 1. The various setting buttons 83 are buttons for displaying on the liquid crystal display 80 a screen for performing various settings of the multifunction apparatus 1. The mode buttons 84, 85, 86, and 87 are buttons for setting the mode of the composite apparatus 1, respectively. Here, a copy mode button 84, a memory card print mode button 85, a film print mode button 86, and a scan mode button 87 are provided as mode buttons.

  On the right side of the liquid crystal display 80, there are an OK button 89A, a cancel button 89B, a save button 89C, a color copy button 89D, a monochrome copy button 89E, a stop button 89F, a cross button 89G, and a menu button 89H. Is provided. When the OK button 89A is pressed, the setting conditions are determined based on the contents displayed on the liquid crystal display 80. When the cancel button 89B is pressed, the setting conditions are cleared and each setting item is changed to a default value. The color copy button 89D is a button for starting color copy. The monochrome copy button 89E is a button for starting monochrome copy. The stop button 89F is a button for stopping the copy operation once started. The cross button 89G can be selectively pressed at the four positions on the top, bottom, left and right, and one button performs four functions (up button, down button, left button, and right button functions). Menu button 89 </ b> H switches setting items displayed on liquid crystal display 80.

=== Configuration of Control Unit 50 ===
FIG. 6 is a block configuration diagram showing a system configuration of the control unit 50 of the composite apparatus 1 according to the present embodiment.

  The control unit 50 of the multifunction apparatus 1 includes a CPU 90 that controls the entire multifunction apparatus 1, a memory 92 that stores a control program, a control ASIC 94 that controls each of the scanner function, print function, and local copy function, An SDRAM 96 capable of directly reading and writing data from the CPU 90 and an operation panel 2 as input means are connected by a CPU bus 98. The control ASIC 94 is provided with an ASIC SDRAM 102.

  The control ASIC 94 includes a scanner control unit 104, a resizing unit 106, a binarization processing unit 108, an interlace processing unit 110, an image buffer unit 112, a CPU interface unit 114, a head control unit 116, and an external host. A USB interface 118 serving as input / output means for the computer 140 and a local bus 128 are provided. The ASIC SDRAM 102 is provided with a line buffer 120, a resize buffer 122, an interlace buffer 124, and image buffers 126 and 127, respectively.

  The scanner control unit 104 controls the exposure lamp 66, the image sensors 72A and 72B, the drive motor 77 of the scanner carriage 60, and the like included in the scanner unit 10. The scanner control unit 104 sends out the image data read via the image sensors 72A and 72B.

  The resizing unit 106 receives image data of a predetermined size, changes the size of the image data, and sends the resized image data. The binarization processing unit 108 converts the transmitted multi-gradation RGB data into CMYK binary data (or 2-bit data), and transmits the converted data to the interlace processing unit 110.

  The interlace processing unit 110 stores the CMYK binary data (or 2-bit data) sent from the binarization processing unit in the interlace buffer 124 of the ASIC SDRAM 102. Then, the interlace processing unit 110 reads the CMYK binary data (or 2-bit data) stored in the interlace buffer 124 for each predetermined size, rearranges the data to correspond to the nozzle arrangement, and sends it to the image buffer unit 112. To do.

  The image buffer unit 112 generates head drive data for causing each nozzle to eject ink for each movement of the printer carriage 41 from the data sent from the interlace processing unit 110. Here, the image buffer unit 112 stores head drive data in image buffers 126 and 127 provided on the SDRAM 102. The image buffers 126 and 127 store head drive data for each time the printer carriage 41 moves once.

  The CPU interface unit 114 enables the CPU 90 to access the ASIC SDRAM 102 connected to the control ASIC 94. Here, the head drive data generated by the image buffer unit 112 is sent from the image buffers 126 and 127 to the head control unit 116 via the CPU interface unit 114.

  The head control unit 116 drives the head 21 based on the head drive data sent from the CPU 90 and ejects ink from the nozzles # 1 to # 180 of the head 21.

=== Data Flow in the Control Unit 50 ===
<About the scanner function>
The host computer 140 connected to the USB interface 118 of the control ASIC 94 transmits an image reading command signal from the scanner unit 10 and reading information data such as reading resolution and reading area to the control unit 50. In the control unit 50, the scanner control unit 104 is controlled based on the image reading command signal and the reading information data, and reading of the document 5 by the scanner unit 10 is started. At this time, the scanner control unit 104 drives the exposure lamp 66, the image sensors 72A and 72B, and the drive mechanism 62, reads the image data sequentially from the image sensors 72A and 72B, and temporarily stores them in the line buffer 120 of the ASIC SDRAM 102. The scanner control unit 104 performs inter-line correction processing on the image data stored in the line buffer 120 and outputs the image data to the host computer 140 via the USB interface 118.

<About the printer function>
In the printer function, the printer driver of the host computer 140 converts image data into head drive data, and the head drive data is input from the USB interface 118. The head drive data is stored in the image buffer 132 assigned to the SDRAM 96 connected to the CPU bus 98. The image buffer 132 includes two memory areas (image buffers 133 and 134). Each of the image buffers 133 and 134 has a capacity capable of storing head drive data for printing by a single movement of the carriage 41 for the printer. When data for one movement is written in one image buffer 133, the data is transferred to the head control unit 116. At this time, when the head drive data of one image buffer 133 is transferred to the head control unit 116, the head drive data for printing in the next movement is stored in the other image buffer 134. When data for one movement is written in the other image buffer 134, the data is transferred to the head control unit 116, and the image data is written in the one image buffer 133. In this manner, the head 21 is driven by the head control unit 116 and printing is performed while alternately writing and reading the head drive data using the two image buffers 133 and 134.

<About copy function>
Next, the data flow during the copy function will be described. Data read by the scanner unit 10 is taken into the line buffer 120 via the scanner control unit 104. The image data captured in the line buffer 120 is sequentially subjected to inter-line correction processing and then sent from the scanner control unit 104 to the binarization processing unit 108.

  The image data sent to the binarization processing unit 108 is converted into binary data for each color of CMYK based on a lookup table 136 stored in the ASIC SDRAM 102 and sent to the interlace processing unit 110. .

  The CMYK binary data sent to the interlace processing unit 110 is stored in the interlace buffer 124 of the ASIC-side SDRAM 102 and rearranged by the interlace processing unit 110 so as to correspond to the nozzle arrangement. The data rearranged by the interlace processing unit 110 is sent to the image buffer unit 112.

  In the image buffer unit 112, the data sent from the interlace processing unit 110 is aligned so as to become head drive data for causing the nozzles # 1 to # 180 to eject ink for each movement of the carriage 41 for the printer. And stored in the image buffers 126 and 127.

  The head drive data for each movement stored in the image buffers 126 and 127 is read by the CPU 90 via the CPU interface unit 114 and transferred to the head control unit 116. The head control unit 116 performs printing by driving the head 21 based on the transferred head drive data.

=== Film reading ===
In the composite apparatus 1 of the present embodiment, the scanner unit 10 can read an image from a photographic film. FIG. 7 illustrates a case where an image is read from a photographic film by the composite apparatus 1. In addition, as a film read here, a negative film may be sufficient and a positive film may be sufficient.

  When reading an image from a photographic film, the reflector 13 provided inside the document table cover 12 is removed as shown in FIG. Here, the reflecting plate 13 mounted on the inside of the document table cover 12 is slid along the arrow C in the figure, and the reflecting plate 13 is removed from the document table cover 12. An exposure lamp 67 for reading a film is provided on the back side of the reflecting plate 13. The exposure lamp 67 is integrally provided inside the document table cover 12 and can be used by removing the reflection plate 13 from the document table cover 12.

  When reading an image from the film, the film is placed on the platen 11. At this time, the film may be set, for example, in a dedicated holder so that the film can be easily positioned on the document table 11. After placing the film on the document table 11, the document table cover 12 is closed. In this case, for example, the reading operation is executed by operating the film printing mode button 86, the scanning mode button 87, or the like on the operation panel 2.

  FIG. 8 explains a reading operation method at the time of film reading. When the document table cover 12 is closed, an exposure lamp 67 inside the document table cover 12 is disposed so as to face the film 18 placed on the document table 11 as shown in FIG. When reading the film, light is emitted from the exposure lamp 67 inside the document table cover 12. That is, when the film is read, the exposure lamp 67 inside the document table cover 12 is used instead of the exposure lamp 66 provided in the scanner carriage 60. The light emitted from the exposure lamp 67 inside the document table cover 12 passes through the film 18 on the document table 11. Then, the light transmitted through the film 18 enters the image sensor 72B through the lens 70B of the scanner carriage 60. The image sensor 72B reads an image from the film 18 placed on the document table 11 by sensing the incident light.

=== Image sensor ===
FIG. 9 illustrates an example of the image sensors 72A and 72B. In this embodiment, the image sensors 72A and 72B are installed inside the scanner carriage 60. As shown in the figure, the scanner carriage 60 is formed long along a direction that intersects the moving direction (carriage moving direction) of the scanner carriage 60. When reading an image, the scanner carriage 60 extends along the carriage moving direction. Slide in parallel. On the upper part of the scanner carriage 60, a lens 70A for making light incident on the image sensor 72A and a lens 70B for making light incident on the image sensor 72B are provided facing the document table 11. The light reflected from the document is incident on the lens 70A. Further, light that passes through the film as an original enters the lens B. These lenses 70A and 70B are arranged along the longitudinal direction of the scanner carriage 60, that is, the direction intersecting the carriage movement direction. Further, an exposure lamp 66 for irradiating light to the document 5 via the document table 11 is provided above the scanner carriage 60 in parallel with the lens 70A. The length Lk1 of the lens 70A and the exposure lamp 66 is set in accordance with the maximum width of the document placed on the document table 11. The length Lk2 of the lens 70B is set corresponding to the width dimension of the film (the width dimension of the exposure lamp 67 for reading the film inside the document cover 12).

  Inside the scanner carriage 60, a substrate 73 provided with image sensors 72A and 72B is disposed. As shown in the figure, the image sensors 72A and 72B correspond to the lenses 70A and 70B, respectively, along the longitudinal direction of the scanner carriage 60, that is, the direction crossing the carriage movement direction, like the lenses 70A and 70B. Is provided. The length dimension Ls1 of the image sensor 72A is set corresponding to the length Lk1 of the lens 70A. Further, the length dimension Ls2 of the image sensor 72B is set corresponding to the length Lk2 of the lens 70B. For example, a plurality of photoelectric conversion elements such as photodiodes are arranged side by side along the longitudinal direction on the upper surface portions of the image sensors 72A and 72B.

  FIG. 10 illustrates in detail the configuration of the lens 70A and the image sensor 72A. The lens 70A has a plurality of individual lenses 71A.

  Similarly, the lens 70B has a plurality of individual lenses. The light incident on each individual lens 71A is received by a plurality of photoelectric conversion elements such as photodiodes provided in the image sensor 72B.

=== Scanner Control Unit ===
FIG. 11 illustrates an example of the configuration of the scanner control unit 104. As shown in the figure, the scanner control unit 104 includes a controller 202, a motor control unit 204, a lamp control unit 206, a sensor control unit 208, an AFE (Analog Front End) unit 210, a digital processing circuit 216, and the like. And a data output circuit 218. Further, the AFE unit 210 includes an analog signal processing circuit 212 and an A / D conversion circuit 214.

  The controller 202 controls the motor control unit 204, the lamp control unit 206, the sensor control unit 208, the AFE unit 210, the digital processing circuit 216, and the data output circuit 218 according to commands from the CPU 90 (see FIG. 6) and the like. The motor control unit 204 performs drive control of the drive motor 77 for moving the scanner carriage 60 according to a command from the controller. The lamp control unit 206 controls light emission of the exposure lamp 66. The sensor control unit 208 controls the image sensors 72A and 72B. The sensor control unit 208 also corresponds to a “signal output unit”.

  The analog signal processing circuit 212 of the AFE unit 210 performs signal processing on the analog signals of the images read by the image sensors 72A and 72B. The A / D conversion circuit 214 of the AFE unit 210 performs A / D conversion of the image signal processed by the analog signal processing circuit 212 into a digital signal.

  A digital signal processing circuit 216 performs digital signal processing on the digital signal transmitted from the A / D conversion circuit 214 of the AFE unit 210. Here, specifically, various image processing and the like are performed, including correction processing such as shading correction. The digital signal subjected to the digital signal processing is output to the outside by the data output circuit 218 as image data (image data) read from the document. Here, the image data output by the data output circuit is output to the host computer 140 through the USB interface 118 or sent to the resizing unit 106 (see FIG. 6).

=== Photoelectric Conversion Element ===
FIG. 12 illustrates a photoelectric conversion element provided in the image sensor 72B. As shown in the figure, the image sensor 72B according to the present embodiment has three colors RGB photodiodes 302R, 302B, and 302G, that is, a photodiode 302R corresponding to red (R) and a blue ( A photodiode 302B corresponding to B) and a photodiode 302G corresponding to green (G) are provided.

  The three-color photodiodes 302R, 302B, and 302G are arranged in a line along the carriage movement direction. Using the three-color photodiodes 302R, 302B, 302G arranged in the carriage movement direction as one unit, the data of one pixel constituting the read image by the three photodiodes 302R, 302B, 302G in one unit. Is supposed to generate. A single unit of three-color photodiodes 302R, 302B, and 302G are arranged in a line along the direction that intersects the carriage movement direction, that is, the longitudinal direction of the image sensor 72B. It is configured.

  Further, the image sensor 72B is provided with a register 304 for taking out charges generated in the three-color photodiodes 302R, 302B, and 302G, and a charge transfer unit (CCD: charge-coupled device) 306. Yes. The register 304 is provided to send the charges generated in the three-color photodiodes 302R, 302B, and 302G to the charge transfer unit 306, and is commonly used for the three colors RGB. First gates 308R, 308B, and 308G are provided between the photodiodes 302R, 302B, and 302G and the register 304, respectively. When the charges are taken out from the photodiodes 302R, 302B, 302G, the corresponding first gates 308R, 308B, 308G are opened. A second gate 310 is provided between the register 304 and the charge transfer unit 306. When charge is sent from the register 304 to the charge transfer unit 306, the second gate 310 is opened.

  The charges generated in the three-color photodiodes 302R, 302B, and 302G move to the charge transfer unit 306 through the common register 304. The charge transfer unit 306 temporarily accumulates the charges transferred from the three-color photodiodes 302R, 302B, and 302G through the register 304. The charge transfer unit 306 corresponds to a “charge storage unit”. The charge transfer unit 306 sequentially transfers the temporarily accumulated charges to the detection circuit 312. The detection circuit 312 sequentially detects the amount of charge transferred by the charge transfer unit 306. The detection circuit 312 outputs the charge amount detection result to the AFE unit 210 (see FIG. 11) of the scanner control unit 104.

=== Order of charge transfer ===
13A to 13C illustrate the order in which the charges generated in the photodiodes 302R, 302B, and 302G of red (R), blue (B), and green (G) move. FIG. 13A illustrates the movement of charges generated in the red (R) photodiode 302R. FIG. 13B illustrates the movement of charges generated in the blue (B) photodiode 302B. FIG. 13C illustrates the movement of charges generated in the green (G) photodiode 302G.

  Here, first, as shown in FIG. 13A, the charge generated in the red (R) photodiode 302 </ b> R is moved to the charge transfer unit 306. In order to move the charge generated in the red (R) photodiode 302R to the charge transfer unit 306, the first gate 308R and the second gate 310 corresponding to the red (R) photodiode 302R are opened. (The part shown in gray in the figure). At this time, the first gates 308B and 308G corresponding to the blue (B) photodiode 302B and the green (G) photodiode 302G are closed. As a result, charges generated in the red (R) photodiode 302 </ b> R move to the charge transfer unit 306.

  Next, as shown in FIG. 13B, the charge generated in the blue (B) photodiode 302 </ b> B is moved to the charge transfer unit 306. In order to move the charge generated in the blue (B) photodiode 302B to the charge transfer unit 306, the first gate 308B and the second gate 310 corresponding to the blue (B) photodiode 302B are opened. (The part shown in gray in the figure). At this time, the first gates 308R and 308G corresponding to the red (R) photodiode 302R and the green (G) photodiode 302G are closed. As the first gate 308 </ b> B and the second gate 310 are thus opened, the charge generated in the blue (B) photodiode 302 </ b> B moves to the charge transfer unit 306. As a result, charges generated in the blue (B) photodiode 302 </ b> B move to the charge transfer unit 306.

  Further, as shown in FIG. 13C, the charge generated in the green (G) photodiode 302G is moved to the charge transfer unit 306. In order to move the charge generated in the green (G) photodiode 302G to the charge transfer unit 306, the first gate 308G and the second gate 310 corresponding to the green (G) photodiode 302G are opened. (The part shown in gray in the figure). At this time, the first gates 308R and 308B corresponding to the red (R) photodiode 302R and the blue (B) photodiode 302B are closed. As the first gate 308G and the second gate 310 are thus opened, the charges generated in the green (G) photodiode 302G move to the charge transfer unit 306. As a result, charges generated in the green (G) photodiode 302 </ b> G move to the charge transfer unit 306.

=== Method of transferring charges ===
Next, a method for moving charges generated in the photodiodes 302R, 302B, and 302G to the charge transfer unit 306 will be described. Here, a case where the charge generated in the red (R) photodiode 302R is moved to the charge transfer unit 306 will be described as an example.

  FIG. 14A to FIG. 14D are cross-sectional views schematically illustrating a method of moving charges generated in the red (R) photodiode 302R. FIG. 14A shows a state when charge is generated in the photodiode 302R. FIG. 14B shows a state in which the charge generated in the photodiode 302 </ b> R moves to the charge transfer unit 306. 14C and 14D show the state after the charge generated in the photodiode 302R has moved to the charge transfer unit 306. FIG.

  The photodiode 302R, the first gate 308R, the register 304, the second gate 310, and the charge transfer unit 306 are formed on the semiconductor substrate 314 as shown in FIG. 14A. Here, the photodiode 302R is formed on the semiconductor substrate 314 by a pn junction as shown in FIG. When light hits the photodiode 302R from the outside, charge is generated and accumulated in the potential well 320 formed by the pn junction according to the amount of the received light.

  The first gate 308R, the register 304, the second gate 310, and the charge transfer unit 306 are formed by the electrode units 316A, 316B, 316C, and 316D provided on the semiconductor substrate 314. That is, the electrode portions 316A, 316B, 316C, and 316D are formed corresponding to the positions of the first gate 308R, the register 304, the second gate 310, and the charge transfer portion 306, respectively. A voltage is applied to each electrode portion 316A, 316B, 316C, 316D, whereby a depletion layer is formed in the semiconductor substrate 314 below each electrode portion 316A, 316B, 316C, 316D. The depletion layers form potential wells 322, 324, 326, and 328, respectively, as shown in the figure. The potential wells 322, 324, 326, and 328 are formed by the first gate 308R, the resistor 304, and the second, respectively. A gate 310 and a charge transfer unit 306 are formed.

  When the charge accumulated in the potential well 320 of the photodiode 302R is moved to the charge transfer unit 306, a high voltage is applied to each of the electrode units 316A, 316B, 316C, and 316D, as shown in FIG. 14B. The potentials of the potential wells 322, 324, 326, and 328 of the gate 308R, the register 304, the second gate 310, and the charge transfer unit 306 are increased. As a result, the first gate 308R and the second gate 310 are opened. Here, the potentials of the potential wells 322, 324, 326, and 328 of the first gate 308R, the register 304, the second gate 310, and the charge transfer unit 306 gradually increase from the first gate 308R to the charge transfer unit 306. Is set as follows. That is, the potential well 324 of the register 304 is set to a potential higher than the potential well 322 of the first gate 308R, the potential well 326 of the second gate 310 is set to a potential higher than the potential well 324 of the register 304, The potential well 328 of the charge transfer unit 306 is set to a higher potential than the potential well 326 of the second gate 310. Application of a high voltage to each electrode part 316A, 316B, 316C, 316D is performed for a predetermined time. During this time, the charges accumulated in the potential well 320 of the photodiode 302R move from the photodiode 302R to the charge transfer unit 306 via the first gate 308R, the register 304, and the second gate 310.

  After the charge of the photodiode 302R moves to the charge transfer unit 306 in this way, the opened first gate 308R is then closed as shown in FIG. 14C. Here, a low voltage is applied to the electrode portion 316A corresponding to the first gate 308R, the potential of the potential well 322 of the first gate 308R is lowered, and the first gate 308R is closed. Here, a low voltage is also applied to the electrode portion 316 </ b> B corresponding to the register 304 to lower the potential of the potential well 324 of the register 304.

  Thereafter, as shown in FIG. 14D, a low voltage is applied to the electrode portion 316C corresponding to the second gate 310, the potential of the potential well 326 of the second gate 310 is lowered, and the second gate 310 is closed. In addition, a low voltage is applied to the electrode portion 316D corresponding to the charge transfer portion 306 to lower the potential of the potential well 328 of the charge transfer portion 306.

  Thereby, the process of moving the charge generated in the photodiode 302R to the charge transfer unit 306 is completed. The charges that have moved to the charge transfer unit 306 are transferred to the detection circuit 312. Then, the detection circuit 312 detects the amount of charge.

=== Conventional problems ===
In such an image sensor 72B, the following problems may occur. The problem is that a part of the charge remains in the photodiodes 302R, 302B, and 302G when the charges generated in the photodiodes 302R, 302B, and 302G are moved to the charge transfer unit 306. This defect is also called a linearity defect.

  FIG. 15 explains this problem. That is, as shown in the figure, for example, when the charge generated in the photodiode 302R is moved to the charge transfer unit 306, all the charges in the potential well 320 of the photodiode 302R are all transferred to the charge transfer unit. Instead of moving to 306, some charges remain as residual charges in the potential well 320 of the photodiode 302R. Further, a part of the charge remains in the potential well 324 of the register 304 while moving to the charge transfer unit 306.

  In particular, in the case of the image sensor 72 </ b> B of the present embodiment, such a residual charge is often generated when the charge generated in the red (R) photodiode 302 </ b> R is moved to the charge transfer unit 306. This is because when the charge generated in the red (R) photodiode 302R is moved to the charge transfer unit 306, the movement distance of the charge is another photodiode, that is, the blue (B) photodiode 302B or the green (G This is presumed to be caused by the fact that it is longer than that of the photodiode 302G. Residual charges are more likely to be generated due to the longer charge movement distance than the other photodiodes 302B and 302G.

  When such a residual charge is generated, the charge amount of the charge generated in the photodiode 302R cannot be accurately detected by the detection circuit 312. As a result, for example, a vertical stripe or the like is added to the read image. Adverse effects such as the occurrence of defects may occur.

  In particular, when the light reflected from the document is received as in the image sensor 72A of the present embodiment, there is a sufficient amount of light, and even if the above-described linearity failure occurs, it is not greatly affected. . However, when reading an image from a film or the like, the light transmitted through the film or the like is received, so the amount of light is less than that when reading the light reflected from the document, and this greatly affects the above-described linearity defect. I will receive it.

  For this reason, with respect to an image sensor that receives light transmitted from the film, such as the image sensor 72B, it is necessary to accurately detect the photodiodes 302R, 302B, and 302G (photoelectric conversion elements) that generate residual charges by inspection. There is. However, an inspection method that can easily detect a photodiode (an element having poor linearity) in which such residual charges are generated has not been proposed.

=== Inspection method ===
In the present embodiment, in order to easily determine whether or not the photodiodes 302R, 302B, and 302G (photoelectric conversion elements) provided in the image sensor 72B have a poor linearity, the following inspection method is performed.

  In this inspection method, when the charges generated in the photodiodes 302R, 302B, and 302G are moved to the charge transfer unit 306, the first gate 308R and the second gate 310 are compared with the case where an image is actually read from a document. Shorten the opening time. As described above, by shortening the opening time of the first gates 308R, 308B, and 308G and the second gate 310, it is difficult to move charges from the photodiodes 302R, 302B, and 302G to the charge transfer unit 306. By making it difficult for such charges to move, it is clarified whether or not a linearity defect has occurred in the photodiode 302R. That is, by making it difficult for the charge to move from the photodiodes 302R, 302B, and 302G to the charge transfer unit 306, the amount of charge that moves to the charge transfer unit 306 is reduced. Since this is detected by the detection circuit 312, it is possible to easily determine whether or not a linearity defect has occurred in the photodiodes 302R, 302B, and 302G.

  When shortening the opening time of the first gates 308R, 308B, 308G and the second gate 310, a high voltage is applied to the electrode portions 316A, 316D corresponding to the first gates 308R, 308B, 308G and the second gate 310. To shorten the time.

  FIG. 16 shows an example of a signal for applying a high voltage to the electrode portions 316A and 316D at the time of image reading and inspection. The upper part of FIG. 16 shows an example of a signal for applying a high voltage to the electrode portions 316A and 316D at the time of image reading. The lower part of FIG. 16 shows an example of a signal for applying a high voltage to the electrode portions 316A and 316D at the time of inspection.

  At the time of image reading, as shown in the upper part of FIG. 16, a signal having a pulse for applying a high voltage for a predetermined time Ta to the electrode portion is output. The signal output here corresponds to a “first control signal”. On the other hand, at the time of inspection, as shown in the lower part of FIG. 16, a signal having a pulse for applying a high voltage for a predetermined time Tb to the electrode part is output. The signal output here corresponds to a “second control signal”. Here, the predetermined time Tb at the time of inspection is set shorter than the predetermined time Ta at the time of image reading. Specifically, for example, when the predetermined time Ta at the time of image reading is 488 μs, the predetermined time Tb at the time of inspection is set to about half of 250 μs.

  Here, it is sufficient that the predetermined time Tb at the time of inspection is shorter than the predetermined time Ta at the time of image reading. For example, when the predetermined time Ta at the time of image reading is 488 μs, the predetermined time Tb at the time of inspection is 400 μs, 300 μs, or 200 μs.

  Thus, by shortening the time for applying a high voltage to the electrode portions 316A and 316D corresponding to the first gates 308R, 308B, and 308G and the second gate 310, the first gates 308R, 308B, and 308G and the second gate 310 The opening time can be shortened. Note that the opening times of the first gates 308R, 308B, and 308G and the second gate 310 need not be the same. That is, when the first gates 308R, 308B, and 308G are closed earlier than the second gate 310, the opening time of the first gates 308R, 308B, and 308G and the opening time of the second gate 310 are set differently. May be. In the present embodiment, the time for applying a high voltage to the electrode unit 316B corresponding to the register 304 is also shortened compared to the case where an image is actually read from a document.

=== Inspection procedure ===
FIG. 17 is a flowchart illustrating an example of the inspection procedure. Here, first, light is applied to the photoelectric conversion elements to be inspected (here, the photodiodes 302R, 302B, and 302G), and charges are generated in the photoelectric conversion elements to be inspected (S202). Next, the charge generated in the photoelectric conversion elements (photodiodes 302R, 302B, 302G) is moved to the charge storage unit (here, the charge transfer unit 306) (S204). At this time, in the present embodiment, the first gates 308R, 308B, 308G and the first gates 308R, 308G, and 308G are used to move the charges generated in the photoelectric conversion elements (photodiodes 302R, 302B, 302G) to the charge storage unit (charge transfer unit 306). Two gates 310 are opened. The opening times of the first gates 308R, 308B, and 308G and the second gate 310 are set to be shorter than when an image is actually read from a document.

  Next, the charge amount of the charge that has moved to the charge storage unit (charge transfer unit 306) in such a short open time is detected by the detection circuit 312 or the like (S206). Then, the detected charge amount is compared with a predetermined value (S208). As a result, when the detected charge amount is equal to or less than a predetermined value, it is determined that the photoelectric conversion element (photodiode 302R, 302B, 302G) has a poor linearity (S210). On the other hand, if the detected charge amount is not less than the predetermined value, that is, if the detected charge amount exceeds the predetermined value, the linearity defect of the photoelectric conversion element (photodiode 302R, 302B, 302G). (S212). In this way, it is determined whether or not the photoelectric conversion element (photodiode 302R, 302B, 302G) to be inspected has a poor linearity. After the determination, the process is immediately terminated.

  Here, the inspection is performed for each of the RGB photodiodes 302R, 302B, and 302G. However, the inspection may be performed only for the red (R) photodiode 302R in which a linearity defect is likely to occur. . Further, in the case where the photodiode that is likely to cause linearity failure is a photodiode other than red (R), that is, a blue (B) photodiode 302B or a green (G) photodiode 302R, Only the photodiodes 302B and 302G may be inspected.

  The program stored in the memory 92 or the like of the composite apparatus 1 applies light to the photoelectric conversion elements (here, the photodiodes 302R, 302B, and 302G) to be inspected in order to perform such inspection. And the first gates 308R, 308B, 308G and the second gates in order to move the charges generated in the photoelectric conversion elements (photodiodes 302R, 302B, 302G) to the charge storage unit (here, the charge transfer unit 306). A step of opening the gate 310 for a shorter time than when reading an image from a document, a step of detecting the amount of charge transferred to the charge storage unit (charge transfer unit 306) by the detection circuit 312 and the like, It is determined whether or not the photoelectric conversion elements (photodiodes 302R, 302B, and 302G) to be defective have poor linearity And a code for executing the steps that. Further, this program may include a code for executing a step of storing information on the determination result in an appropriate storage unit and a step of transmitting the determination result to the outside.

=== Actual inspection ===
Next, an actual inspection method will be specifically described using an example thereof.
18A and 18B illustrate an example of an actual inspection method. In the actual inspection, the photoelectric conversion elements provided in the image sensor 72B, that is, the photodiodes 302R, 302B, and 302G are simultaneously performed. Here, in the image sensor 72B, the photodiodes 302R, 302B, and 302G corresponding to red (R), blue (B), and green (G), respectively, are photodiodes for one pixel, and photodiodes for 2576 pixels are provided. It is assumed that the image sensors 72B are arranged in a line along the longitudinal direction of the image sensor 72B.

  When actually inspecting these photoelectric conversion elements, for example, 120 lines of pixels are read for each of 2576 pixels of photodiodes as shown in FIG. Thus, 120 sample values are acquired and inspected. Then, an average value is obtained for each of the obtained 120 pieces of sample data for each photoelectric conversion element (photodiode) of each pixel. Then, as shown in FIG. 18B, the obtained average value and the predetermined threshold value Vk are compared for each photoelectric conversion element (photodiode), and the obtained average value is equal to or less than the predetermined threshold value Vk. To check. In the case of a photoelectric conversion element (photodiode) in which a linearity failure has occurred, the average value is equal to or less than a predetermined threshold value Vk as shown in FIG. On the other hand, in the case of a photoelectric conversion element (photodiode) in which no linearity failure has occurred, the average value exceeds a predetermined threshold value Vk as shown in FIG. From this, it is possible to easily check whether or not a linearity defect has occurred in the photoelectric conversion element (photodiode).

<Linearity characteristics>
FIG. 19A illustrates an example of linearity characteristics of a photoelectric conversion element (here, a photodiode) in which no linearity failure has occurred. FIG. 19B illustrates an example of linearity characteristics of a photoelectric conversion element (photodiode) in which a linearity failure has occurred.

  When no linearity failure occurs, the detection output (detected charge amount) increases in proportion to the amount of light received by the photoelectric conversion element (photodiode) as shown in FIG. 19A. Further, when the shading correction is performed on the output (detected charge amount), the linearity characteristic is corrected by multiplying the output (detected charge amount) by a predetermined coefficient as shown in FIG. .

  On the other hand, when a linearity failure occurs, as shown in FIG. 19B, even if the amount of light received by the photoelectric conversion element (photodiode) increases, the output (detected charge amount) is output unless a certain amount of light is reached. Not come. This is because the charge remains in the photoelectric conversion element (photodiode) as it is without being transferred to the charge storage section (charge transfer section 306) in the photoelectric conversion element (photodiode). Even when the amount of light received reaches a certain amount, some of the charge remains in the photoelectric conversion element (photodiode), so that linear characteristics cannot be obtained. Here, the fixed light amount is, for example, about 1 to 5% when the maximum detected light amount of the photoelectric conversion element (photodiode) is 100%.

  Furthermore, even if the output (detected charge amount) is subjected to shading correction and the output (detected charge amount) is multiplied by a predetermined coefficient, the output (detected charge amount) Since it does not come out, a linear characteristic cannot be obtained.

  Compared with the linearity characteristics after shading correction when the photoelectric conversion element (photodiode) is normal, it can be confirmed that the maximum error ΔVmax occurs when the light amount is about 1 to 5%.

  For this reason, when the inspection is actually performed, when the maximum detected light amount of the photoelectric conversion element (photodiode) is set to 100%, the above-described inspection is performed with the light amount set to about 1 to 5%. Thus, it can be more accurately determined whether or not the photoelectric conversion element (photodiode) has poor linearity, which is preferable.

<Inspection method>
In actual inspection, in order to adjust the amount of light incident on the photoelectric conversion element (photodiode) to about 1 to 5%, the light transmittance is about 1 to 5%. Use optical film. Specifically, the translucent film is set instead of the original on the original table 11 of the composite apparatus 1 of the present embodiment. Thereafter, the document table cover 12 is closed, and light is emitted from the exposure lamp 67 inside the document table cover 12. The image sensor 72B detects the light emitted from the exposure lamp 67 inside the document table cover 12 and transmitted through the translucent film and incident on the lens 70 of the scanner carriage 60. Based on the detection result, it is checked whether a linearity defect has occurred in the photoelectric conversion element (photodiode). Thereby, a test | inspection of a photoelectric conversion element (photodiode) can be easily implemented by about 1 to 5% of light quantity.

=== How to deal with poor linearity ===
In such an inspection, when it is determined that the photoelectric conversion element (photodiode) has a poor linearity, information for specifying the position or the like of which photoelectric conversion element (photodiode) is the nonvolatile memory It is preferable to store in a storage unit such as. For example, in the composite apparatus 1 of this embodiment, it is preferable to store the information in the memory 92 or the like.

  By storing such information in a non-volatile memory or the like, when the image is read from the document by the image sensor 72B, it is possible to perform complement processing on the read image data. In other words, the pixel data read by the photoelectric conversion element (photodiode) determined to have a poor linearity can be corrected with the data of the surrounding pixels to obtain an appropriate image. In this embodiment, for example, the complementary processing may be performed by the digital processing circuit 216 of the scanner control unit 104 or the like.

  Of course, when it is determined that the photoelectric conversion element (photodiode) has a poor linearity, it may be implemented by another corresponding method.

=== Inspection timing ===
Timing for inspecting whether or not the photoelectric conversion element (photodiode) has a linearity defect includes the following timing.

(1) Before product shipment After production, the product is inspected for linearity defects before shipping as a product. By performing such an inspection, even if a photoelectric conversion element having a linearity defect is found in the image sensor 72B or the like, it can be shipped as a product in a state corresponding to this.

(2) After product shipment After being shipped as a product, it is inspected for linearity defects during maintenance. By performing such an inspection, it is possible to detect and deal with a linearity defect that occurs in a photoelectric conversion element for a later reason after it is shipped as a product.

  Actually, the timing for inspecting the photoelectric conversion element (photodiode) for a linearity defect may be implemented at a timing other than (1) and (2).

=== Summary ===
In the present embodiment, when the charges generated in the photoelectric conversion elements (here, the photodiodes 302R, 302B, and 302G) are moved to the charge accumulation unit (here, the charge transfer unit 306), an image is actually taken from the original. Does the linearity defect occur in the photoelectric conversion elements (photodiodes 302R, 302B, 302G) by shortening the open time of the gates (here, the first gate 308R and the second gate 310) compared to the case of reading? It is possible to easily determine whether or not.

  Here, the same photoelectric conversion element (photodiode 302R, 302B, 302G) is inspected a plurality of times (here, 120 times), a plurality of sample data is obtained, and an average is obtained from these sample data. By obtaining the value and comparing it with the predetermined value Vk, it is possible to check whether or not a linearity defect has occurred in the photoelectric conversion element more accurately.

  In addition, if information related to a photoelectric conversion element (photodiode) determined to have a poor linearity is stored in a nonvolatile memory or the like, when the image is read from the document by the image sensor 72B, a complementary process is performed on the read image data. Can be applied. Thereby, an appropriate image can be obtained.

=== Other Embodiments ===
As mentioned above, based on one embodiment, the present invention has been described by taking a composite apparatus as an example. However, the above embodiment is for facilitating understanding of the present invention, and the present invention is limited and interpreted. Not for. The present invention can be changed or improved without departing from the gist thereof, and needless to say, the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<About photoelectric conversion element>
In the above-described embodiment, the photodiodes 302R, 302B, and 302G are used as the “photoelectric conversion elements”. However, the “photoelectric conversion elements” here are not limited to the photodiodes 302R, 302B, and 302G. Absent. In other words, any type of element may be used as long as it generates an electric charge by the photoelectric effect.

  Further, in the above-described embodiment, as the “photoelectric conversion element”, three-color photons including a red (R) photodiode 302R, a blue (B) photodiode 302B, and a green (G) photodiode 302G are used. Although diodes are used, it is not always necessary to use the three-color photodiodes 302R, 302B, and 302G as the “photoelectric conversion elements” here. That is, if it is a “photoelectric conversion element”, it is not always necessary to correspond to the three colors of red (R), blue (B), and green (G), and a photodiode corresponding to monochrome may be used.

<About the charge storage unit>
In the embodiment described above, the case of the charge transfer unit 306 has been described as an example of the “charge storage unit”. However, in the case of the “charge storage unit”, the case of such a charge transfer unit 306 is described. Not only, but if the charge generated by the photoelectric conversion element moves and accumulates, it corresponds to a “charge accumulation unit”.

  Further, in the above-described embodiment, the charges generated in the three color photodiodes of the red (R) photodiode 302R, the blue (B) photodiode 302B, and the green (G) photodiode 302G are the same. The “charge storage unit” (charge transfer unit 306) moves in common, but the “charge storage unit” (charge transfer unit 306) is not necessarily limited to such a case. That is, a separate “charge storage unit” (charge transfer unit 306) may be provided for each of the three color photodiodes.

<About the gate>
In the above-described embodiment, the first gates 308R, 308B, and 308G and the second gate 310 are provided as the potential wells 322 and 326 on the semiconductor substrate 314 as the “gate”. In this case, the first gates 308R, 308B, and 308G and the second gate 310 are not limited. That is, regarding the “gate”, the two gates of the first gates 308R, 308B, and 308G and the second gate 310 are not necessarily provided as described above, and are provided between the photoelectric conversion element and the charge storage unit. One “gate” may be provided. Three or more “gates” may be provided.

  Further, the “gate” here does not necessarily need to be formed as the potential wells 322 and 326 on the semiconductor substrate 314, and is provided between the photoelectric conversion element and the charge storage unit, and charge storage from the photoelectric conversion element is performed. Any type of “gate” may be used as long as it can control whether or not charge can be transferred to the portion.

<About defects>
In the above-described embodiment, the photoelectric conversion element is inspected to determine whether or not the linearity is defective. However, when the image reading operation is performed on the gate provided between the photoelectric conversion element and the charge storage unit. As long as it is a defect that can be examined by opening it for a shorter period of time, other types of defects occurring in the photoelectric conversion element may be inspected.

<About image sensors>
In the above-described embodiment, the image sensors 72A and 72B in which photoelectric conversion elements (photodiodes 302R, 302B, and 302G) are arranged in a straight line along a predetermined direction are taken as an example of the image sensor. As described above, the “image sensor” here is not necessarily limited to such an image sensor 72.

The perspective view explaining an example of a compound device. The perspective view when the cover of the scanner part of a compound apparatus is opened. The perspective view which shows the printing part of a composite apparatus. FIG. 3 is an explanatory diagram illustrating configurations of a scanner unit and a printer unit of the multifunction apparatus. Explanatory drawing explaining the operation panel of a compound apparatus. Explanatory drawing of an example of the system configuration | structure of the control part of a compound apparatus. Explanatory drawing in the case of reading an image from a film. Explanatory drawing of the reading operation at the time of film reading. Explanatory drawing of an example of an image sensor. FIG. 3 is an explanatory diagram illustrating an example of an internal configuration of a scanner carriage. FIG. 3 is an explanatory diagram illustrating an example of a configuration of a scanner control unit. Explanatory drawing of the structure of the photoelectric conversion element provided in the image sensor. Explanatory drawing of the movement of the electric charge of a red (R) photodiode. Explanatory drawing of the movement of the electric charge of a photodiode of blue (B). Explanatory drawing of the movement of the electric charge of a green (G) photodiode. Explanatory drawing at the time of the electric charge generation of a photodiode (photoelectric conversion element). Explanatory drawing when an electric charge moves to a charge storage part (charge transfer part). Explanatory drawing when the gate is closed. Explanatory drawing when the gate is closed. Explanatory drawing of the conventional problem. Explanatory drawing of the inspection method of this embodiment. Explanatory drawing of an example of the test | inspection procedure of this embodiment. Explanatory drawing of an actual inspection method. Explanatory drawing of an actual inspection method. Explanatory drawing of an example of the linearity characteristic when the linearity defect has not generate | occur | produced. Explanatory drawing of an example of the linearity characteristic when a linearity defect generate | occur | produces.

Explanation of symbols

1 composite device, 2 operation panel, 3 paper discharge unit, 4 paper supply unit, 5 document,
7 discharge tray, 8 paper feed tray, 10 scanner unit, 11 document table,
12 document table cover, 13 reflector, 14 platen, 15 transport motor,
17A conveying roller, 18 film, 21 head, 24 drive mechanism,
30 printer section, 32 opening section, 34 hinge section, 36 transport mechanism,
41 Carriage, 42 Carriage motor, 44 Pulley,
45 timing belt, 46 guide rail, 50 control unit,
51 linear encoder code plate, 52 detector, 53 paper detection sensor,
56 rotary encoder, 60 carriage for scanner, 62 drive mechanism,
64 guides, 66 exposure lamps, 67 exposure lamps,
70A lens, 70B lens, 71A individual lens, 72A image sensor,
72B image sensor, 73 substrate, 74 timing belt, 75 pulley,
76 pulley, 77 drive motor, 80 liquid crystal display, 81 notification lamp,
82 Power button, 83 Various setting buttons, 84 Copy mode button,
85 Memory card print mode button, 86 Film print mode button,
87 Scan mode button, 88 Feed / discharge button,
89A OK button, 89B Cancel button, 89C Save button,
89D color copy button, 89E monochrome copy button,
89F stop button, 89G cross button, 89H menu button,
90 CPU, 92 memory, 94 control ASIC, 96 SDRAM,
98 CPU bus, 102 SDRAM for ASIC,
104 Scanner control unit, 106 Resizing unit,
108 binarization processing unit, 110 interlace processing unit,
112 image buffer unit, 114 CPU interface unit,
116 head control unit, 118 USB interface,
120 line buffer, 122 resize buffer,
124 interlace buffer, 126 image buffer,
127 image buffer, 128 local bus, 132 image buffer,
133 image buffer, 134 image buffer,
136 lookup table, 140 host computer,
202 controller, 204 motor control unit, 206 lamp control unit,
208 sensor control unit, 210 AFE unit, 212 analog signal processing circuit,
214 A / D conversion circuit, 216 digital processing circuit, 218 data output circuit,
302R photodiode, 302B photodiode,
302G photodiode, 304 register, 306 charge transfer unit,
308R first gate, 308B first gate, 308G first gate,
310 second gate, 312 detection circuit, 314 semiconductor substrate,
316A electrode part, 316B electrode part, 316C electrode part, 316D electrode part,
320 potential well, 322 potential well, 324 potential well,
326 potential well, 328 potential well

Claims (11)

Applying light to the photoelectric conversion element to generate charges in the photoelectric conversion element;
In order to move the charge generated in the photoelectric conversion element from the photoelectric conversion element to a charge storage unit, a gate provided between the photoelectric conversion element and the charge storage unit is used to display an image by the photoelectric conversion element. A step of opening only for a shorter time than a predetermined time of opening when performing the reading operation;
The amount of charge transferred to the charge storage unit by opening the gate for the short time, and the amount of charge transferred to the charge storage unit by opening the gate for the predetermined time. Detecting the amount of charge reduced compared to ,
Determining whether or not the photoelectric conversion element is defective based on the detected amount of charge after reduction ;
A method for inspecting a photoelectric conversion element, comprising:   The photoelectric conversion element inspection method according to claim 1, wherein the photoelectric conversion element is a photodiode. 3. The method for inspecting a photoelectric conversion element according to claim 1 , wherein the detected amount of electric charge after the decrease is compared with a predetermined value to determine whether or not the photoelectric conversion element is defective.   The method for inspecting a photoelectric conversion element according to any one of claims 1 to 3, further comprising a step of storing, in a memory, information relating to the photoelectric conversion element determined to be defective. And a step of moving the charge moved to the charge storage unit to a detection circuit for detecting the charge amount of the charge in order to detect the charge amount after the decrease of the charge moved to the charge storage unit. The method for inspecting a photoelectric conversion element according to claim 1, wherein:   The photoelectric conversion according to any one of claims 1 to 5, wherein when the electric charge is generated in the photoelectric conversion element, light that has passed through a transmission film having a predetermined transmittance is applied to the photoelectric conversion element. Element inspection method.   The photoelectric conversion element inspection method according to claim 1, wherein there are a plurality of the photoelectric conversion elements.   The inspection of the photoelectric conversion element according to any one of claims 1 to 7, wherein the photoelectric conversion elements are three photoelectric conversion elements that respectively receive light of three colors of red, blue, and green. Method.   A register through which the charge generated in the photoelectric conversion element moves to the charge storage unit is provided between the three photoelectric conversion elements and the charge storage unit. A first gate is provided as the gate between each of the conversion elements, a second gate is provided as the gate between the register and the charge storage unit, and the three photoelectric conversion elements, the charge storage unit, 9. The method for inspecting a photoelectric conversion element according to claim 8, wherein the distances between are different from each other. It has an image sensor for reading images from the document,
The image sensor includes a photoelectric conversion element that generates a charge by received light, and
A charge accumulating portion to which the charge generated in the photoelectric conversion element moves; and
A gate provided between the photoelectric conversion element and the charge storage unit and opened to move the charge from the photoelectric conversion element to the charge storage unit;
A signal output unit for outputting a first control signal for opening the gate for a predetermined time and a second control signal for opening the gate for a time shorter than the predetermined time;
The amount of charge transferred to the charge storage unit by opening the gate for the short time, and the amount of charge transferred to the charge storage unit by opening the gate for the predetermined time. A charge amount detection unit that detects a reduced charge amount , and
An image reading apparatus comprising: In order to move the charge generated in the photoelectric conversion element by applying light to the photoelectric conversion element from the photoelectric conversion element to the charge storage unit, a gate provided between the photoelectric conversion element and the charge storage unit, Opening for a short time compared to a predetermined time to open when performing an operation of reading an image with the photoelectric conversion element;
The amount of charge transferred to the charge storage unit by opening the gate for the short time, and the amount of charge transferred to the charge storage unit by opening the gate for the predetermined time. Obtaining information on the amount of charge reduced compared to ,
Determining whether or not the photoelectric conversion element is defective based on the acquired information;
Having a code for causing the image reading apparatus to execute the program.