JP2007103577A - Electromagnetic wave detector and radiation imaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic detector without generating any large difference in output level between the output of both the ends and the output of the inside in a group of signal leading wires arranged outside the pixel region of a signal line. <P>SOLUTION: In the electromagnetic wave detector having a signal line for reading an electric signal converted by a transducer, the transducer for converting electromagnetic waves to electric signals and a pixel made of switch elements connected to the transducer are arranged two-dimensionally on an insulating substrate. In the electromagnetic wave detector, a signal leading wire 16 arranged outside the pixel region of the signal line forms a plurality of wiring groups at the edge of an insulating substrate, a constant-potential wire that becomes fixed potential at least when reading a signal is arranged outside the signal leading wire at both the ends of each group of wires, and the interval between the constant potential wire and the signal leading wire at both the edges of each group of wires is made nearly equal to the interval between all signal leading wires. The constant potential wire is a bias leading wire 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetic wave detection device that converts an electromagnetic wave including radiation such as visible light and infrared light, X-ray, α-ray, β-ray, γ-ray and the like into an electrical signal, and a radiation imaging system using the electromagnetic wave detection device. About. In particular, it is suitably used for a radiation detection device for detecting radiation, and is applied to a medical diagnostic imaging device, a nondestructive inspection device, an analysis device using radiation and the like.

  A conventional radiation detection apparatus is a combination of a wavelength converter that converts incident radiation into light in a wavelength region that can be photoelectrically converted and a photoelectric conversion apparatus, or an apparatus in which a semiconductor conversion element directly converts incident radiation into an electrical signal. It is. The photoelectric conversion device has a photoelectric conversion element as a semiconductor conversion element and a TFT (thin film transistor) as a switch element in one pixel, and each pixel is two-dimensionally arranged.

  In a conventional photoelectric conversion device, a pixel including a photoelectric conversion element that converts light into an electrical signal and a switch element connected to the photoelectric conversion element is two-dimensionally arranged on an insulating substrate. Furthermore, a bias line for applying a bias to the photoelectric conversion element on the insulating substrate, a gate line for supplying a drive signal to the switch element, and a signal line for reading an electrical signal converted by the photoelectric conversion element are provided.

  As shown in Patent Documents 1 and 2 below, a pixel region on an insulating substrate and a signal readout circuit outside the insulating substrate are connected via a TCP (tape carrier package). The signal line is connected to the TCP by a lead wiring outside the pixel region. On the other hand, although it is not a photoelectric conversion device, there is a liquid crystal display device as a similar technical field in that a lead-out wiring is used when a pixel region on an insulating substrate and a circuit outside the insulating substrate are connected via TCP.

  In the liquid crystal display device (liquid crystal display) disclosed in Patent Document 3 below, a proposal has been made for the configuration of the lead-out wiring.

  FIG. 6 is a plan view of a conventional liquid crystal display device, and FIG. 7 is a plan view of an electrode substrate constituting a conventional liquid crystal display element.

  FIG. 6 shows a connection state between the liquid crystal display device 101 and the liquid crystal drive PCB (printed circuit board) 102, the TCP 104 on which the drive semiconductor IC chip 103 is mounted.

  In FIG. 7, a part of the lead wiring on the right side from the center line of the terminal group corresponding to one TCP mounted on the electrode substrate is shown. The number of electrodes of one TCP, which is a driving element, is usually about 80 to 160, but is omitted here.

111 is an electrode substrate in which an electrode is formed on one surface on a transparent insulating substrate, and constitutes a liquid crystal display element. The 2 ₁ to 2 ₈ display electrodes constituting the pixel, a transparent conductive film, are formed in parallel on a surface of the electrode substrate 111. Reference numerals 3 _{1 to} 3 ₈ are terminals (connection electrodes) connected to the TCP electrodes, and 1 ₁ to ₁₈ are diagonal straight lines that are a part of the lead lines connecting the display electrodes 2 and the terminals 3. is there. 112 is a TCP alignment mark when TCP is mounted on the electrode substrate 111, 113 is a center line of a terminal group corresponding to one TCP mounted on the electrode substrate 111, and 114 is provided with a sealing material. Part.

Than the pitch of display electrodes 2 _n of the plurality of in parallel to the wiring respectively on the electrode substrate 111, drawn to the edge of the electrode substrate 111, the direction of the pitch of the terminals 3 _n is connected to the TCP becomes narrower. Therefore, the lead-out wiring 1 that connects them is required. The lead-out wiring is composed of a portion extended as it is from the display electrode 2 _n, a portion extended as it is from the terminal 3 _n , and a parallel diagonal straight line 1 _n connecting the two extended portions. Further, the oblique straight wiring 1 _n has the same angle θ with respect to the display electrode 2 _n and the terminal 3 _n . In Patent Document 3, the lengths of the two extended portions and the width of the oblique straight wiring 1 _n are adjusted so that the wiring resistances of the lead wirings are equal to each other. Moreover, it is substantially equal interval between the slanted straight lines 1 _n.
JP 2001-274420 A JP 2004-96000 A JP-A-8-76136

  2. Description of the Related Art In recent years, with the development of liquid crystal panel manufacturing technology using TFTs, the screen size of a display unit has been increased with the increase in size of the panel. For this reason, as in Patent Document 3, a proposal has been made to improve the area use efficiency in the panel of the lead-out wiring that connects the electrode connected to the TCP and the display electrode. When the length of the lead-out wiring is increased, the area of the lead-out wiring is increased, so that the area use efficiency is lowered. In addition, the wiring resistance of the lead wiring is increased. For this reason, in Patent Document 3, the length and width of the lead-out wiring are adjusted in order to realize a short and low-resistance lead-out wiring. In addition, when the spacing between the diagonal straight lines of the lead-out wiring is non-uniform, non-uniform shading unevenness occurs in a portion (frame portion) where the liquid crystal exists inside the sealing material, which should be essentially black. In order to prevent this, the interval between the diagonal straight lines is made substantially equal. The lead-out wiring forms one wiring group for each TCP unit and is repeatedly arranged for each TCP unit.

  On the other hand, a liquid crystal panel manufacturing technique is applied to an area sensor having a photoelectric conversion element and a TFT, and is used in various fields such as a radiation imaging apparatus such as an X-ray imaging apparatus. However, unlike a liquid crystal display, an X-ray imaging apparatus has a feature that a minute signal is digitally converted and an image is output. For this reason, even if the technology of Patent Document 3 is applied and the distance between the diagonal straight lines is substantially equal in the signal readout lead lines, the lead lines at both ends of each TCP and the lead lines inside the TCPs The parasitic capacitance is different. In other words, the other lead wires are adjacent to both ends of the lead wires inside both ends of the TCP, whereas the lead wires adjacent to the inside of the TCP exist only in the lead wires at both ends of the TCP. As a result, there is a problem that a large output step is generated between the output at both ends of the TCP and the output inside thereof.

  An object of the present invention is to provide an electromagnetic wave detection device in which a large output step does not occur between the output at both ends and the output inside thereof in each signal lead-out wiring group arranged outside the pixel region of the signal line.

In order to solve the above-described problems, an electromagnetic wave detection device according to the present invention is a two-dimensional array of pixels each including a conversion element that converts an electromagnetic wave into an electrical signal and a switch element connected to the conversion element on an insulating substrate. In the electromagnetic wave detection device having a signal line for reading the electric signal converted by the conversion element,
The signal lead-out lines arranged outside the pixel area of the signal lines form a plurality of wiring groups at the end of the insulating substrate, and at a constant potential at least at the time of signal reading outside the signal lead-out lines at both ends of each of the wiring groups. A constant potential wiring is provided. The distance between the constant potential wiring and the signal lead-out lines at both ends of each wiring group is substantially equal to the distance between all the signal lead-out lines.

  Note that in this specification, a conversion element that converts electromagnetic waves into electrical signals refers to electromagnetic waves in a wavelength region from light such as visible light and infrared light to radiation such as X-rays, α-rays, β-rays, and γ-rays. The element which receives this and converts this electromagnetic wave into an electric signal is shown. The conversion element in the present invention includes a photoelectric conversion element that converts light such as visible light and infrared light into an electric signal, and an element that converts radiation such as X-rays having amorphous selenium or the like as a semiconductor layer into an electric signal. It is a waste.

  In the present invention, in each signal lead-out wiring group arranged outside the pixel area of the signal line, constant potential wiring is disposed outside the signal lead-out wiring at both ends of each wiring group, and the constant potential wiring and the signal lead-out wiring are connected to each other. The interval between each wiring is made equal. As a result, the coupling capacity of the signal lead-out wiring can be made the same so that a large output step does not occur between the outputs at both ends and the outputs inside thereof.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings together with examples. The following embodiments will be described with respect to a case where a radiation detection device is configured. However, the electromagnetic wave detection device of the present invention is not limited to a radiation detection device that converts radiation into an electrical signal, and emits light such as visible light and infrared light. The present invention can also be applied as a photoelectric conversion device that converts electric signals. Note that the radiation imaging apparatus is an apparatus including a sensor substrate and a peripheral circuit that can be regarded as a radiation detection apparatus.

[Embodiment 1]
Hereinafter, a radiation imaging apparatus according to a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram of a radiation imaging apparatus of the present invention, FIG. 2 is an equivalent circuit diagram, and FIG. 3 is an enlarged plan view of a portion A at an end portion of an insulating substrate in FIG.

  In FIG. 1, a photoelectric conversion substrate 11 which is a photoelectric conversion device constitutes a radiation detection device by combining a phosphor 15 which is a typical wavelength converter (scintillator) for converting radiation into visible light. The radiation imaging apparatus includes the radiation detection apparatus, a TCP (tape carrier package) 14, a gate drive device 12 that is a printed circuit board (PCB), and a readout device 13.

  The photoelectric conversion substrate 11 has a two-dimensional (matrix shape) pixel composed of a photoelectric conversion element that is a conversion element that converts light into an electrical signal and a TFT that is a switch element connected to the photoelectric conversion element on an insulating substrate. Is arranged. The photoelectric conversion element is, for example, a semiconductor conversion element using hydrogenated amorphous silicon. Further, the photoelectric conversion substrate 11 has a bias line for applying a bias to the photoelectric conversion element, a gate line for supplying a drive signal to the switch element, and a signal for reading an electric signal converted by the photoelectric conversion element on the insulating substrate. With lines. The photoelectric conversion substrate 11 is cut at a predetermined cutting portion, and the signal line and the bias line are connected to the reading device 13 and the gate line is connected to the gate driving device 12 via the TCP 14. The phosphor 15 is connected to the photoelectric conversion substrate 11 through an adhesive layer.

  In FIG. 2, P11 to P33 are photoelectric conversion elements, and T11 to T33 are TFTs. Each photoelectric conversion element is connected to common bias lines Vs <b> 1 to Vs <b> 3, and a constant bias is applied from the reading device 13. The gate electrodes of the TFTs are connected to the common gate lines Vg1 to Vg3, and the gate driving device 12 controls ON / OFF of the TFT gates. The source or drain electrode of each TFT is connected to common signal lines Sig 1 to Sig 3, and Sig 1 to Sig 3 are connected to the readout device 13. One photoelectric conversion element and TFT constitute one pixel. Although FIG. 2 shows 3 × 3 pixels in the pixel area, in practice, for example, 2000 × 2000 pixels are arranged on an insulating substrate to constitute a photoelectric conversion substrate.

  The X-rays exposed toward the subject are attenuated and transmitted by the subject, converted into visible light by the phosphor 15 shown in FIG. 1, and this visible light is incident on the photoelectric conversion element, and charges ( Electrical signal). This electric charge is transferred to the signal line through the TFT by the gate drive pulse applied by the gate drive device 12 and read out to the outside by the readout device 13. During this period, the potential of the bias line is fixed at a constant potential. Thereafter, the residual charge of the photoelectric conversion element is reset by switching the potential of the bias line or via the TFT.

  At the end of the photoelectric conversion substrate 11, lead-out wirings for connecting the respective wirings (Vs, Vg, Sig) and TCP are arranged. In FIG. 3, lead lines for the signal line Sig and the bias line Vs are arranged on the readout device 13 side, and a part of the lead line on the right side from the center line of the wiring group corresponding to one TCP mounted on the substrate is shown. Has been. Reference numeral 16 denotes a signal lead-out wiring connected to the signal line in the pixel region. As shown in the figure, the signal lead-out wiring 16 is disposed outside the pixel region. The signal lead-out wiring 16 is used for connection to connect the signal electrodes 16a having the same pitch as the pixels connected to the signal lines and the TCPs 14 disposed at the end of the photoelectric conversion substrate 11 at a pitch smaller than the pixel pitch. It consists of an electrode 16b and a straight electrode 16c connecting the two electrodes. Here, the interval between the signal electrodes 16a is L1, the interval between the connection electrodes 16b is L2, and the interval between the straight electrodes 16c is L3.

  In addition, a bias lead-out line 17 that is a lead-out line for the bias line Vs is disposed outside the signal lead-out line 16 disposed at the end of the TCP 14. The bias lead-out wiring 17 has the same configuration as the signal lead-out wiring 16, and includes a bias electrode 17a connected to the bias line Vs, a connection electrode 18b for connecting the TCP, and a straight electrode 17c connecting the two electrodes. Become. The distance between the bias lead-out line 17 and the signal lead-out lines at both ends is substantially equal to the distance between all the signal lead-out lines. That is, each of L1, L2, and L3 is substantially constant.

  Ideally, the intervals of these L1, L2, and L3 are constant. However, since the photoelectric conversion substrate has a large area, various manufacturing distributions are generated in the substrate in the manufacturing process. For example, it is a film thickness distribution at the time of applying a photoresist used for wiring patterning, for example, a film thickness distribution at the time of forming a metal layer to be a wiring. Thereby, a difference occurs in the wiring width, that is, a difference occurs in the interval between the wirings.

  Specifically, since the specification of variation of a general manufacturing apparatus is ± 10% with respect to the average value, a difference of 20% at maximum in the wiring width occurs in the substrate. For this reason, the interval between the signal extraction wiring and the constant potential wiring may not be completely equal to the interval between the signal extraction wirings. In this case, if the interval between the signal lead-out wiring and the constant potential wiring is L, the signal lead-out wiring width d, and the distance between each signal lead-out wiring is S, the constant potential wiring is arranged so as to satisfy the following relationship. Is desirable.

S-0.1d ≦ L ≦ S + 0.1d
Due to the arrangement of the wirings as described above, the coupling capacitance almost the same as that of the other adjacent signal extraction wirings 16 arranged inside the signal extraction wiring 16 arranged at the outermost end of the TCP 14 is formed. In particular, in the lead-out wiring 16, the straight electrode 16c may be much longer in wiring length than the other electrodes, so it is important to make the distance L3 equal. Further, since the bias lead-out wiring 17 outside the signal lead-out wiring 16 has a constant potential at the time of signal reading, the signal lead-out wiring 16 is hardly affected by noise from the periphery and is shielded in units of TCP. . That is, the configuration of the photoelectric conversion substrate of the present embodiment has an effect that a large output step does not occur between the outputs at both ends of each TCP and the outputs inside thereof. Further, the distances L1, L2 and L3 between the electrodes between the signal lead-out lines are all equal (L1 = L2 = L3), and the distance between the signal lead-out line 17 and the bias lead-out line 21 is also equal to all of these. good.

  In this embodiment, an indirect radiation detection device in which a conversion element is a photoelectric conversion element and combined with a phosphor is shown. However, a direct type that converts radiation directly into an electrical signal using amorphous selenium or the like as the conversion element is shown. Similar effects can be obtained in the radiation detection apparatus. Further, the photoelectric conversion element of the indirect radiation imaging apparatus may be either a MIS type or a PIN type. The pixel structure may be a planar type in which the conversion element and the switch element are configured in the same layer, or a stacked type in which the conversion element is formed on the layer in which the switch element is formed.

[Embodiment 2]
Hereinafter, a radiation imaging apparatus according to a second embodiment of the present invention will be described with reference to the drawings.

  FIG. 4 is an enlarged plan view of the end portion of the insulating substrate of the radiation imaging apparatus.

  The radiation imaging apparatus according to the present embodiment has the same configuration, connection form, equivalent circuit, driving method, and the like as in the first embodiment, and has already been described with reference to FIGS.

  At the end of the photoelectric conversion substrate 11, lead-out wirings for connecting the respective wirings (Vs, Vg, Sig) and TCP are arranged. In FIG. 4, lead lines for the signal line Sig and the bias line Vs are arranged on the readout device 13 side, and a part of the lead line on the right side from the center line of the wiring group corresponding to one TCP mounted on the substrate is shown. Has been. Reference numeral 16 denotes a signal lead-out wiring connected to the signal line in the pixel region. As shown in the figure, the signal lead-out wiring 16 is disposed outside the pixel region. The signal lead-out wiring 16 is used for connection to connect the signal electrodes 16a having the same pitch as the pixels connected to the signal lines and the TCPs 14 disposed at the end of the photoelectric conversion substrate 11 at a pitch smaller than the pixel pitch. It consists of an electrode 16b and a straight electrode 16c connecting the two electrodes. Here, the interval between the signal electrodes 16a is L1, the interval between the connection electrodes 16b is L2, and the interval between the straight electrodes 16c is L3.

  A reference potential wiring 18 and a bias lead wiring 17 that is a lead wiring for the bias line Vs are disposed outside the signal lead wiring 16 disposed at the end of the TCP 14. The reference potential wiring 18 includes a connection electrode 18b for connecting the TCP 14 and a straight electrode 18c, and is arranged up to the vicinity of the pixel. The bias lead-out line 17 has the same configuration as the signal lead-out line 16 and includes a bias electrode 17a connected to the bias line, a connection electrode 17b for connecting the TCP 14, and a straight electrode 17c connecting the two electrodes. . The interval between the reference potential line 18 and the signal lead lines at both ends is made equal to the distance between all the signal lead lines. That is, each of L2 and L3 is constant. L1 is also constant.

  With the arrangement of the wirings as described above, the coupling capacitance is formed in the signal lead-out wiring 16 arranged at the endmost part of the TCP 14 substantially equal to other adjacent signal lead-out wirings arranged inside the TCP 14. In particular, among the lead wires, the straight electrode 16c may have a much longer wire length than other electrodes, so it is important to make the distance L3 equal. Further, since the reference potential wiring 18 outside the signal lead-out wiring 16 is always at the reference potential, the signal lead-out wiring 16 is not easily affected by noise from the periphery, and is shielded in TCP units. That is, the configuration of the photoelectric conversion substrate of the present embodiment has an effect that a large output step does not occur between the outputs at both ends of each TCP and the outputs inside thereof. Further, the distances L1, L2, and L3 between the electrodes between the signal lead-out lines are all equal (L1 = L2 = L3), and the distance between the signal lead-out line 16 and the reference potential line 18 is equal to all of these. good.

  While the first and second embodiments of the present invention have been described above, application examples to the radiation imaging system according to the present invention will be described below.

  FIG. 5 is a diagram showing an application example of a radiation imaging apparatus using the electromagnetic wave detection apparatus of the present invention to a radiation imaging system.

  X-rays 6060 generated by the X-ray tube 6050 pass through the chest 6062 of the patient or subject 6061 and enter a radiation imaging apparatus 6040 having a scintillator (phosphor layer) 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 digitally converted and image-processed by an image processor 6070 serving as signal processing means, and can be observed on a display 6080 serving as display means in a control room.

  Further, this information can be transferred to a remote place by transmission processing means such as a telephone line 6090, and can be displayed on a display 6081 serving as display means such as a doctor room in another place or stored in recording means such as an optical disk. As a result, it is possible for a remote doctor to make a diagnosis. Moreover, it can also record on the film 6110 used as a recording medium by the film processor 6100 used as a recording means.

  The present invention can be applied to an apparatus for detecting radiation such as X-rays for medical use and nondestructive inspection. Further, the present invention can be applied to a photoelectric conversion device that converts light such as visible light into an electric signal, particularly a device having a large-area photoelectric conversion region.

Schematic explaining the radiation imaging apparatus which is the 1st Embodiment of this invention 1 is an equivalent circuit diagram of a radiation imaging apparatus according to a first embodiment of the present invention. FIG. 1 is an enlarged plan view of a portion A at an end portion of an insulating substrate The enlarged plan view in the insulated substrate edge part of the radiation imaging device which is the 2nd Embodiment of this invention Schematic explaining an application example of the radiation imaging apparatus of the present invention to a radiation imaging system Plan view of a conventional liquid crystal display device Plan view of the edge part of the electrode substrate of the conventional liquid crystal display device

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Photoelectric conversion board 12 ... Gate drive device 13 ... Read-out device 14 ... TCP
DESCRIPTION OF SYMBOLS 15 ... Phosphor 16 ... Signal extraction wiring 17 ... Bias extraction wiring 18 ... Reference potential wiring Vg ... Gate line Sig ... Signal line Vs ... Bias line P11-P33 ... Photoelectric conversion element T11-T33 ... TFT
L1... Spacing between each signal electrode L2... Spacing between each connection electrode L3... Spacing between each straight electrode

Claims (9)

A signal line for reading out an electrical signal converted by the conversion element, in which pixels including a conversion element for converting electromagnetic waves into an electric signal and a switch element connected to the conversion element are arranged in a two-dimensional manner on an insulating substrate. In the electromagnetic wave detection device having
The signal lead-out lines arranged outside the pixel area of the signal lines form a plurality of wiring groups at the end of the insulating substrate, and at a constant potential at least at the time of signal reading outside the signal lead-out lines at both ends of each of the wiring groups. The constant potential wiring is arranged, and the interval between the constant potential wiring and the signal lead-out wires at both ends of each wiring group is substantially equal to the interval between all the signal lead-out wires. Electromagnetic wave detection device.   2. Each wiring group of the signal lead-out wiring is provided corresponding to each of a plurality of tape carrier packages that connect a pixel region on the insulating substrate and a circuit outside the insulating substrate. The electromagnetic wave detection apparatus of description.   The signal lead-out wiring includes a signal electrode having the same pitch as the pixel connected to the signal line, a connection electrode disposed at an end of the insulating substrate at a pitch smaller than the pixel pitch, and the two electrodes. The electromagnetic wave detection device according to claim 1, comprising a linear electrode to be connected. When the interval between the signal lead-out wiring and the constant potential wiring is L, the signal lead-out wiring width is d, and the distance between each signal lead-out wiring is S, the constant potential wiring is arranged to satisfy the following relationship. The electromagnetic wave detection device according to any one of claims 1 to 3.
S-0.1d ≦ L ≦ S + 0.1d   2. The bias line for applying a bias to the conversion element is provided on the insulating substrate, and the constant potential wiring is a bias lead wiring arranged outside a pixel region of the bias line. The electromagnetic wave detection apparatus in any one of -4.   A bias line for applying a bias to the conversion element is provided on the insulating substrate, and the constant-potential wiring is disposed outside the pixel region of the signal lead-out wiring and the bias line at both ends of each wiring group. The electromagnetic wave detection device according to claim 1, wherein the electromagnetic wave detection device is a reference potential line arranged between the lead wires.   7. The electromagnetic wave detection device according to claim 1, wherein the incident electromagnetic wave is radiation, and wavelength conversion is performed on the conversion element to convert the radiation into an electromagnetic wave having a wavelength band that can be sensed by the conversion element. An electromagnetic wave detection apparatus further comprising a body.   The electromagnetic wave detection device according to claim 1, wherein the incident electromagnetic wave is radiation, and the conversion element is an element that converts the radiation into an electric signal. The electromagnetic wave detection device according to claim 7 or 8,
Signal processing means for processing a signal from the electromagnetic wave 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.

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