JP2007149749A - Radiation detector, radiation imaging system and photoelectric conversion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively realize a high-function sensor panel of various pixel sizes. <P>SOLUTION: The radiation detector has a plurality of pixels having a sensor section 21 for converting a light into an electric signal, and TFTs 11 for transferring the electric signal converted in the sensor section 21. The pixels consist a plurality of TFTs 11 arranged on a substrate and the sensor section 21 arranged on the TFTs 11 and connected to the TFTs. One sensor section 21 is arranged on the TFTs 11. For driving wirings 13 and signal lines 14, a plurality of lines are connected to a leading-out terminal section 15 so that the TFTs 11 can be simultaneously driven and read for each sensor section 21. With this configuration, various kinds of panels having different pixel sizes can be realized from the same TFT array substrate, common use of the various kinds of panels can be realized, and thus, manufacturing processes can be simplified. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion device that converts light such as visible light and infrared light into an electric signal, a radiation detection device using the photoelectric conversion device, and a radiation imaging system, and particularly digital radiation that detects radiation such as X-rays and γ-rays. The present invention relates to a detection device.

  The digital radiation detection apparatus is an apparatus for which the use is still limited and the cost reduction due to the mass production effect has not been achieved. Particularly in medical applications, there is a strong demand for radiation exposure reduction, that is, improvement in characteristics, and cost reduction is also desired. This is an indispensable problem for the widespread use of digital radiation detection devices.

Against this backdrop, Patent Document 1 proposes a MIS (Metal Insulator Semiconductor) type sensor panel, realizing a low-cost radiation detection apparatus. In this apparatus, the TFT (Thin Film Transistor) element and the sensor element have the same MIS structure, so that the manufacturing process is simplified. In particular, by making the CVD (Chemical Vapor Deposition) apparatus sharable, the price is reduced.
US Pat. No. 6,075,256

  However, in order to further popularize digital radiation detectors in the future, we will offer sensor panels of various types and characteristics in various fields, with low price and high functionality from the current price, sensor characteristics and specifications. It is necessary to do. Further, widespread use can induce mass production effects and can realize a low-cost device.

  For example, in the medical field, a difference between breast imaging and relatively high-definition mammography that require relatively high definition, or a moving image for surgery or a still image for general imaging is required as an imaging part. The characteristics are different, and as a result, the pixel size varies.

  The present invention has been made in consideration of such conventional circumstances, and an object thereof is to realize high-performance sensor panels having various pixel sizes at a low price.

  In order to achieve the above object, a radiation detection apparatus according to the present invention includes, on a substrate, a photoelectric conversion element that converts light into an electrical signal, and a switching element that transfers an electrical signal converted by the photoelectric conversion element. A photoelectric conversion device comprising a plurality of pixels, and comprising a wavelength converter for converting incident radiation into light in a wavelength band that can be sensed by the photoelectric conversion element on the photoelectric conversion element, wherein the pixel is on the substrate And a plurality of switching elements disposed on the plurality of switching elements and a photoelectric conversion element disposed on the plurality of switching elements and connected to the plurality of switching elements. Here, the wavelength converting body converts incident radiation such as X-rays and γ-rays into light in a wavelength band that can be sensed by the photoelectric conversion element.

  In addition, the radiation detection apparatus according to the present invention includes a plurality of pixels on a substrate having a semiconductor element that converts incident radiation into an electrical signal and a switching element that transfers the electrical signal converted by the semiconductor element. In the radiation detection apparatus, the pixel includes a plurality of switching elements disposed on the substrate, and a semiconductor element disposed on the plurality of switching elements and connected to the plurality of switching elements. It is characterized by.

  In the present invention, it further includes a plurality of drive wires connected to the plurality of switching elements, and a drive wire lead terminal portion connected to the plurality of drive wires, and the drive wire lead terminal portion includes the plurality of drive wires. The drive wiring may be formed so as to be integrated into one terminal for each pixel. And a plurality of signal lines connected to the plurality of switching elements, and a signal line lead terminal portion to which the plurality of signal lines are connected. It may be formed so as to be integrated into one terminal every time.

  A radiation imaging system according to the present invention includes any one of the radiation detection apparatuses described above, a signal processing means for processing a signal from the radiation detection apparatus, and a recording means for recording a signal from the signal processing means. A display means for displaying a signal from the signal processing means; a transmission processing means for transmitting a signal from the signal processing means; and a radiation source for generating the radiation. And

  A photoelectric conversion device according to the present invention includes, on a substrate, a plurality of pixels each including a photoelectric conversion element that converts light into an electric signal and a switching element that transfers an electric signal converted by the photoelectric conversion element. In the photoelectric conversion device, the pixel includes a plurality of switching elements disposed on the substrate and a photoelectric conversion element disposed on the plurality of switching elements and connected to the plurality of switching elements. It is characterized by.

  According to the present invention, it is possible to realize various types of panels having different pixel sizes from a substrate on which a plurality of switching elements such as the same TFT array substrate are formed. As a result, it is possible to achieve commonality of multi-product panels and simplify the manufacturing process. As a result, high-performance sensor panels with various pixel sizes can be realized at a low price.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a best mode for carrying out a radiation detection device, a radiation imaging system, and a photoelectric conversion device according to the invention will be described with reference to the drawings.

  In the first embodiment of the present invention, a radiation detection apparatus using an MIS type sensor will be described. The radiation detection apparatus of the present embodiment is applied to an indirect conversion type device that converts radiation into light by a scintillator layer (phosphor layer) that is a wavelength converter and converts it into an electric signal by a photoelectric conversion element. The photoelectric conversion device used in this radiation detection apparatus is composed of a TFT element as a switching element connected to a drive wiring and a signal line, and a sensor element connected to the TFT element. In this configuration, pixel elements determined by a matrix arrangement of drive wirings and signal lines are arranged, and a sensor element formed as one pixel is connected to a plurality of pixel elements. A plurality of signal lines connected to the pixel element are connected to respective terminal portions and integrated into one terminal. A plurality of drive wirings are also connected to the respective terminal portions and integrated into one terminal.

  FIG. 1 shows a schematic plan view of a radiation detection apparatus according to this embodiment. In the figure, 11 is a TFT portion for forming a switching element, and 12 is an individual electrode. Reference numeral 13 denotes a drive wiring for sending a control signal to the gate electrode of the TFT section 11, and reference numeral 14 denotes a signal line for reading a signal from the sensor section 21 through the source / drain of the TFT section 11. Reference numeral 21 denotes a sensor unit (indicated by the outline of a two-dot chain line in the figure) constituting the sensor element. Reference numeral 22 denotes a terminal connection portion, 15 denotes a drive terminal 13 and a lead terminal portion of the signal line 14 provided in the terminal connection portion 22, and 23 denotes a final lead terminal opening portion provided in the terminal connection portion 22. The lead terminal portion 15 of the drive wiring 13 is connected to a drive circuit (not shown) via a final lead terminal opening 23, and the lead terminal portion 15 of the signal line 14 is read out via a final lead terminal opening 23 ( (Not shown).

  In the example in the figure, a scintillator (not shown) as a wavelength converter is mounted on the sensor unit 21. The scintillator mounting process can be applied to either a method in which a scintillator (phosphor) is laminated on a sensor panel or a method in which the scintillator is laminated directly on the sensor panel. In this configuration, radiation such as X-rays is converted into light having a wavelength that can be detected by a photoelectric conversion element by a scintillator (not shown), and the light enters the sensor unit 21. Incident light is photoelectrically converted and accumulated in the sensor unit 21, and the signal is read out to a readout circuit (not shown) by the transfer operation of the TFT unit 11.

  In this embodiment, a 2 × 2 pixel element composed of the TFT portion 11 functions as a single pixel. That is, one sensor unit 21 is disposed on a 2 × 2 pixel element. In accordance with this, the drive wiring 13 connected to the gate electrode of the TFT portion 11 and the signal line 14 connected to the SD (source / drain) electrode are connected to the lead terminal portion 15 by two lines in the lead connection portion 22. Are connected to each other. As a result, each of the sensor units 21 constituting a single pixel has a structure capable of simultaneously driving and simultaneously reading a plurality of TFT units 11 constituting 2 × 2 pixel elements. This connection structure is simultaneously formed at the stage of creating the sensor portion 21 formed on the TFT array, that is, on the individual electrode 12. In this embodiment, the 2 × 2 pixel element functions as one pixel. However, the pixel size is not limited to this. For example, a 3 × 3 pixel element may function as one pixel. One pixel element may function as one pixel.

  FIG. 2 is a schematic cross-sectional view taken along a line AA in FIG.

  In FIG. 2, 101 is a glass substrate, 102 is a gate electrode, 103 is a gate insulating film, 104 is a TFT semiconductor layer, 105 is a TFT channel protective film, 106 is an ohmic contact layer, and 107 is a TFT SD electrode. Reference numeral 108 denotes a protective layer, 109 denotes an interlayer insulating layer, and 110 denotes an individual electrode. Reference numeral 201 denotes a sensor insulating layer, 202 denotes a sensor semiconductor layer, 203 denotes a carrier blocking layer, 204 denotes a sensor transparent electrode, 205 denotes a sensor bias line, and 206 denotes a protective film. In this way, by forming the sensor part on the TFT array via the interlayer insulating layer 109, the aperture ratio is increased, and the wiring width of signal lines and the like is increased to reduce noise, thereby achieving an improvement in sensor sensitivity. can do.

  In this embodiment, the sensor semiconductor layer 202 is disposed across the plurality of individual electrodes 110. According to this, even if one pixel element is defective, it can be driven by the other three pixel elements, which is effective in reducing pixel defects and has the advantage of improving the image quality.

  FIG. 3 is a schematic cross-sectional view taken along the line BB in FIG.

  3, 101 is a glass substrate, 103 is a gate insulating film, 108 and 206 are protective films, 301 is an extraction electrode formed simultaneously with the TFT SD electrode 107 in FIG. 2, and 302 is formed simultaneously with the individual electrode 110 in FIG. 2 is a terminal connection portion formed simultaneously with the sensor transparent electrode 204 in FIG. 2, and 304 is a final extraction terminal opening.

  As described above, in this embodiment, for example, in order for a 2 × 2 pixel element to function as a single pixel, one sensor is arranged on the 2 × 2 pixel element, and the drawer connection portion also has 2 The line is connected at the lead-out terminal so that it can be driven and read simultaneously. This connection structure is formed at the same time as the sensor part is formed on the TFT array as described above. In this embodiment, a case where a 2 × 2 pixel element is caused to function as one pixel is illustrated, but for example, a 3 × 3 pixel element is allowed to function as one pixel, or a 1 × 1 pixel element is assumed to be one pixel. It is also possible to make it function.

  Therefore, according to the present embodiment, various types of panels having different pixel sizes can be realized using the same TFT array substrate. As a result, it is possible to achieve commonality of multi-product panels and simplify the manufacturing process. As a result, lower prices and improved characteristics can be achieved at the same time.

  In addition, the structure which integrated the sensor part shown in FIG. 2 and the structure which integrated the terminal part shown in FIG. 3 can achieve price reduction enough by employ | adopting either one structure. For example, the aperture ratio of the structure of FIG. 2 is improved, and if a driving method such as multi-line driving is devised, an essential cost reduction and high functionality can be achieved. Further, the structure of FIG. 3 has an advantage that sticking of an external driver and an amplifier IC can be reduced. However, in order to obtain the maximum effect, it is desirable to adopt both structures. In the present embodiment, the MIS type sensor is described as an example. Basically, the present invention functions effectively also in the PIN type sensor.

  In this embodiment, as the amorphous silicon TFT, an inverted stagger type (bottom gate type) is used, but a stagger type (top gate type) may be used. A polysilicon TFT may be used in place of the amorphous silicon TFT.

  In this embodiment, the case where a TFT is used as an example of the switching element is described. However, the present invention is not necessarily limited to this. For example, a diode may be used as the switching element.

  In the second embodiment of the present invention, a radiation detection apparatus using a TFT array substrate of an LCD (Liquid Crystal Display) panel will be described.

  FIG. 4 is a schematic plan view of the present embodiment. In the figure, 11 is a TFT section, 12 is an individual electrode, 13 is a drive wiring, 14 is a signal line, 15 is a lead terminal section, and 21 is a sensor section (indicated by the outline of a two-dot chain line in the figure). The present embodiment is a 3 × 3 pixel sensor, and one pixel is composed of three pixel elements (pixel elements corresponding to the three primary color patterns of red, green, and blue of the color filter used in the LCD).

  In the present embodiment, three pixel elements constitute one pixel. At this time, one integrated pixel is a square, and each pixel element is a rectangle divided into a plurality of equal parts. That is, the pixel structure used in the liquid crystal display element up to the TFT array is a structure that is mass-produced at a low price, and has a great advantage in reducing the cost of the sensor. Of course, integration from the individual electrodes 12 as well as the sensor is also conceivable.

  Therefore, according to the present embodiment, in addition to the same effects as described above, the radiation detection apparatus can be manufactured using the TFT array substrate mass-produced by the LCD as it is, and further cost reduction is realized. It becomes possible.

  In each of the above-described embodiments, a radiation detection apparatus using an indirect conversion type sensor that converts incident radiation into light with a scintillator and detects the light with a photoelectric conversion element is illustrated. In contrast, in a third embodiment of the present invention, a radiation detection apparatus using a direct sensor such as CdTe that directly converts incident radiation into an electrical signal will be described.

  FIG. 5 is a schematic sectional view of the present embodiment. In the figure, 101 is a glass substrate, 102 is a gate electrode, 103 is a gate insulating film, 104 is a TFT semiconductor layer, 105 is a TFT channel protective film, 106 is an ohmic contact layer, and 107 is a TFT SD electrode. Reference numeral 108 denotes a protective layer, 109 denotes an interlayer insulating layer, and 110 denotes an individual electrode. Reference numeral 301 denotes a conductive resin connection part, 302 denotes a sensor part individual electrode, 303 denotes a direct conversion material (semiconductor element) such as CdTe, and 304 denotes a sensor common electrode. In this embodiment, a plurality of pixel elements of the TFT array are connected to one pixel of the sensor array. Therefore, the connection method is basically the same regardless of whether it is a batch or individual as shown in FIG. In this configuration, radiation such as X-rays is directly converted into an electric signal by the conversion material 303 and read out to a reading circuit (not shown) by a transfer operation of the TFT portion.

  In this embodiment, CdTe is exemplified as the direct conversion material (semiconductor element) constituting the direct sensor, but the present invention is not limited to this, and for example, a-Se (amorphous selenium) material. Etc.

  In each of the above-described embodiments, the radiation detection apparatus has been described. However, the present invention is not necessarily limited thereto, and can be applied to a completely stacked photoelectric conversion apparatus. For example, it is used for a photoelectric conversion device including a plurality of pixels each including a photoelectric conversion element that converts light into an electric signal and a switching element that transfers an electric signal converted by the photoelectric conversion element on a substrate. it can. In this case, the pixel includes a plurality of switching elements arranged on the substrate and photoelectric conversion elements arranged on the plurality of switching elements and connected to the plurality of switching elements.

  In the fourth embodiment of the present invention, a radiation imaging system using the radiation detection apparatus according to the present invention will be described.

  FIG. 6 is a schematic diagram of this embodiment. In FIG. 6, the X-ray 6060 generated by the X-ray tube 6050 passes through the chest 6062 of the patient or subject 6061 and enters the radiation detection device 6040 having a scintillator mounted thereon. This incident X-ray includes information inside the body of the patient 6061. The scintillator emits light in response to the incidence of X-rays, and this is photoelectrically converted to obtain electrical information. This information is converted to digital. The image is processed by the image processor 6070 and can be observed on the display 6080 in the control room.

  Further, this information can be transferred to a remote place by a transmission means such as a telephone line 6090 and can be displayed on a display 6081 such as a doctor room in another place or stored in a storage means such as an optical disk, and a doctor at a remote place makes a diagnosis. It is also possible. It can also be recorded on the film 6110 by the film processor 6100.

  INDUSTRIAL APPLICABILITY The present invention can be applied to the use of a completely stacked photoelectric conversion device and a radiation detection device using the photoelectric conversion device, and particularly applicable to medical image diagnostic devices, nondestructive inspection devices, analysis devices using radiation, and the like.

1 is a schematic plan view of a radiation detection apparatus according to a first example of the present invention. It is typical sectional drawing of the AA part of FIG. It is typical sectional drawing of the BB part of FIG. It is a typical top view of the radiation detection apparatus using the TFT array of the LCD panel which concerns on the 2nd Example of this invention. It is typical sectional drawing of the direct type | mold radiation detection apparatus which concerns on the 3rd Example of this invention. It is a schematic diagram explaining the radiation imaging system using the radiation detection apparatus which concerns on the 3rd Example of this invention.

Explanation of symbols

11 TFT portion 12 Individual electrode 13 Drive wiring 14 Signal line 15 Lead terminal portion 21 Sensor portion 22 Terminal connection portion 23 Final lead terminal opening 109 Interlayer insulating layer 110 Individual electrode 201 Sensor insulating layer 202 Sensor semiconductor layer 204 Sensor transparent electrode 205 Sensor Bias line 206 Protective film 301 Conductive resin connection part 302 Sensor part individual electrode 303 Direct conversion material 304 such as CdTe Sensor common electrode

Claims (8)

Radiation incident on a photoelectric conversion element having a plurality of pixels each having a photoelectric conversion element that converts light into an electric signal and a switching element that transfers an electric signal converted by the photoelectric conversion element. In a radiation detection apparatus comprising a wavelength conversion body that converts light into a wavelength band that can be sensed by the photoelectric conversion element,
The pixel includes a plurality of switching elements disposed on the substrate and a photoelectric conversion element disposed on the plurality of switching elements and connected to the plurality of switching elements. Detection device. In a radiation detection apparatus comprising a plurality of pixels each having a semiconductor element that converts incident radiation into an electrical signal and a switching element for transferring the electrical signal converted by the semiconductor element on a substrate.
The pixel includes a plurality of switching elements disposed on the substrate and a semiconductor element disposed on the plurality of switching elements and connected to the plurality of switching elements. apparatus. A plurality of drive wirings connected to the plurality of switching elements; and a drive wiring lead terminal portion connected to the plurality of drive wirings;
The radiation detection apparatus according to claim 1, wherein the drive wiring lead-out terminal portion is formed so that the plurality of drive wirings are integrated into one terminal for each pixel. A plurality of signal lines connected to the plurality of switching elements; and a signal line lead-out terminal portion to which the plurality of signal lines are connected;
4. The radiation detection apparatus according to claim 1, wherein the signal line lead-out terminal portion is formed so that the plurality of signal lines are integrated into one terminal for each pixel. 5. . The radiation detection apparatus according to any one of claims 1 to 4,
Signal processing means for processing signals from the radiation detection device;
Recording means for recording a signal from the signal processing means;
Display means for displaying a signal from the signal processing means;
Transmission processing means for transmitting a signal from the signal processing means;
A radiation imaging system comprising: a radiation source for generating the radiation. On a substrate, a photoelectric conversion device having a plurality of pixels each having a photoelectric conversion element that converts light into an electric signal and a switching element that transfers an electric signal converted by the photoelectric conversion element.
The pixel includes a plurality of switching elements disposed on the substrate, and a photoelectric conversion element disposed on the plurality of switching elements and connected to the plurality of switching elements. Conversion device. A plurality of drive wirings connected to the plurality of switching elements; and a drive wiring lead terminal portion connected to the plurality of drive wirings;
The photoelectric conversion device according to claim 6, wherein the drive wiring lead terminal portion is formed so that the plurality of drive wirings are integrated into one terminal for each pixel. A plurality of signal lines connected to the plurality of switching elements; and a signal line lead-out terminal portion to which the plurality of signal lines are connected;
The photoelectric conversion device according to claim 6, wherein the signal line lead terminal portion is formed so that the plurality of signal lines are integrated into one terminal for each pixel.

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