JP2007155564A - Radiation detector and radiation image detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To arrange a plurality of radiation detecting elements in parallel without clearance on a substrate, and to detect a radiation image with high resolution by suppressing the occurrence of dead space of the radiation detection. <P>SOLUTION: The radiation detecting elements 21 having a first electrode surface 23 and a second electrode surface 40 positioned on the opposite side of the first electrode surface 23 are mounted on the substrate 22, a conductive sheet 37 is adhered to the first electrode surfaces 23 of the radiation detecting elements 21 via a conductive adhesive 36, and the first electrode surfaces are connected to an electric circuit on the substrate 32 via the conductive sheet 37. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radiation detector and a radiation detection apparatus including a radiation detection element on a substrate.

  Conventionally, there is a radiation detector that is used in medical diagnostic equipment, non-destructive inspection devices, and the like and measures the intensity distribution of radiation (see, for example, Patent Document 1).

  In this radiation detector, plating electrodes are provided on both upper and lower surfaces of a CdTe element having a high resistivity, and the wafer in this state is diced into a radiation detection element. This radiation detection element is placed on a substrate having a conductive pattern. It consists of what is electrically connected to.

  In addition, a signal extraction (high voltage application) terminal (for example, a metal pin or electrode pad) provided on the substrate is connected to a plating electrode on the upper surface of the radiation detection element with a wire (gold wire), and the terminal A high voltage can be applied between the terminals connected to the conductive pattern on the substrate.

  By applying this high voltage, a radiation detection signal corresponding to the number of radiations (radiation dose) can be taken out from both terminals.

  FIG. 9 is a plan view conceptually showing such a conventional radiation detector. FIG. 9 shows a radiation detector in which four radiation detection elements 11 are arranged on the substrate 12 in an array.

  The upper and lower surfaces of these radiation detection elements 11 are the upper and lower electrodes of the plating layer. One electrode pad 14 corresponding to each radiation detection element 11 is provided on the substrate 12, and these electrode pads 14 and the corresponding upper surface electrode 13 of each radiation detection element 11 are electrically connected by wires 15. It is connected to the.

A high voltage is applied to each of the radiation detection elements 11 through the electrode pad 14 so that a radiation detection signal can be taken out as described above.
JP-A-8-166461

  However, in the conventional radiation detector, one end of the wire 15 is connected to the upper surface electrode 13 of the radiation detection element 11, the wire 15 is drawn out parallel to the substrate 12, and the other end of the wire 15 is It is necessary to connect to the electrode pad 14 on the substrate 12 protruding from the installation area of each radiation detection element 11.

  On the other hand, in order to enable radiation image detection in a large area by adding such radiation detection elements 11 in an array, it is necessary to arrange the radiation detection elements 11 in parallel without any gaps.

  However, the radiation detection element 11 cannot be disposed at the position of the electrode pad 14 on the substrate 12, resulting in a dead space (radiation insensitive region), and high-resolution radiation image detection cannot be performed. Further, there is a disadvantage that the dead space hinders downsizing of the apparatus.

  The present invention has been made paying attention to the above-mentioned conventional problems, and by arranging a plurality of radiation detection elements side by side on the substrate without gaps, the occurrence of radiation detection dead space can be suppressed. It is an object of the present invention to provide a radiation detector and a radiation detection apparatus that enable detection of a radiation image with high resolution by a miniaturization apparatus.

  In order to achieve the above object, a radiation detector according to the present invention includes a radiation detection element having a first electrode surface and a second electrode surface located on the opposite side of the first electrode surface mounted on a substrate. A conductive sheet is bonded to the first electrode surface of the radiation detection element via a conductive adhesive, and the first electrode surface is electrically connected to the substrate via the conductive sheet. It is characterized by that.

  With this configuration, the first electrode surface (upper surface electrode) and the electrode pad are wire-connected as in the prior art by simply bonding one conductive sheet and a high voltage application connection terminal on the substrate. Can be omitted.

  In addition, since the conductive sheet covers the first electrode surface, it is possible to avoid the destruction and chemical alteration of the first electrode surface due to a mechanical impact from the outside. Furthermore, the heat of the integrated circuit element can be radiated to the outside.

  In the radiation detector according to the present invention, a plurality of the radiation detection elements are mounted on the substrate in a one-dimensional or two-dimensional array, and the first of all the radiation detection elements is interposed via the conductive sheet. The electrode surfaces of 1 are electrically connected.

  With this configuration, a high voltage can be applied to a plurality of radiation detection elements at once from a connection terminal for applying a high voltage on a substrate with a single conductive sheet. In addition, it is possible to prevent a dead space that makes radiation detection impossible between the radiation detection elements.

  Furthermore, since the work of connecting one wire for each radiation detection element is eliminated, the manufacturing process can be simplified and the manufacturing time can be shortened.

  In the radiation detector according to the present invention, the radiation detection element is CdTe or CdZnTe.

  With this configuration, since CdTe and CdZnTe have high resistance, it is possible to apply a high voltage to the radiation detection element. In addition, since radiation absorption efficiency is high, radiation can be detected with high sensitivity.

  In the radiation detector according to the present invention, the size of the conductive sheet is equal to or smaller than the size of the radiation detection element.

  With this configuration, a plurality of radiation detection elements can be arranged side by side on the substrate without gaps in an array without receiving interference from the conductive sheet.

  The radiation detector according to the present invention is characterized in that the size of the conductive sheet is equal to or smaller than the size of the plurality of radiation detection elements arranged in an array.

  With this configuration, radiation detectors having radiation detection elements arranged in an array can be arranged on the substrate without gaps, and a radiation image can be detected in a large area.

  In the radiation detector according to the present invention, the conductive sheet has a cut or a through hole.

  With this configuration, stress generated in the conductive sheet can be relieved, and deformation or breakage of the conductive sheet can be avoided in advance.

  In the radiation detector according to the present invention, the conductive adhesive that bonds the first electrode surface of the radiation detection element and the conductive sheet is a low-elastic conductive adhesive. And

  With this configuration, transmission of stress from one of the conductive sheet and the first electrode surface to the other can be avoided, and deformation and breakage of these can be prevented.

  A radiation detection apparatus according to the present invention includes a radiation detection element having a first electrode surface and a second electrode surface located on the opposite side of the first electrode surface, an integrated circuit element having an integrated circuit, and Is mounted on the substrate, and the first electrode surface of the radiation detection element of the radiation image detection module is connected to the first electrode surface via a conductive adhesive. A conductive sheet is connected, and the substrate and the radiographic image detection module are electrically connected via the conductive sheet.

  With this configuration, it is possible to omit the work of wire-connecting the first electrode surface and the electrode pad as in the prior art by simply bonding one conductive sheet and a connection terminal for applying a high voltage on the substrate. it can.

  In addition, since the conductive sheet covers the first electrode surface, it is possible to avoid the destruction and chemical alteration of the first electrode surface due to a mechanical impact from the outside. Furthermore, the heat of the integrated circuit element can be radiated to the outside.

  In the radiation detection apparatus according to the present invention, a plurality of the radiation image detection modules are mounted on a substrate in a one-dimensional or two-dimensional array, and all the radiation image detection modules are mounted on the substrate by the conductive sheet. It is characterized by being electrically connected.

  With this configuration, a high voltage can be collectively applied to a plurality of radiation image detection modules from a connection terminal for applying a high voltage on a substrate with a single conductive sheet. In addition, it is possible to prevent a dead space that makes it impossible to detect radiation between each radiation image detection module.

  Furthermore, since there is no work for connecting one wire at a time for each radiographic image detection module, and a batch connection process is performed, the manufacturing process can be simplified and the manufacturing time can be shortened.

  In the radiation detection apparatus according to the present invention, the radiation detection element is CdTe or CdZnTe.

  With this configuration, since CdTe and CdZnTe have a high resistance, it is possible to apply a high voltage to the radiation detection element. Moreover, since radiation absorption efficiency is high, radiation detection can be performed with high sensitivity.

  In the radiation detection apparatus according to the present invention, the size of the conductive sheet is equal to or smaller than the size of the radiation detection element.

  With this configuration, a plurality of radiation image detection modules can be arranged side by side on the substrate without gaps in an array without receiving interference from the conductive sheet.

  In the radiation detection apparatus according to the present invention, the size of the conductive sheet is equal to or smaller than the size of the plurality of radiation image detection modules arranged in an array.

  With this configuration, radiation image detection modules having radiation detection elements arranged side by side in an array can be arranged side by side on the substrate without gaps, and a large area radiation image can be detected.

  In the radiation detection apparatus according to the present invention, the conductive adhesive that bonds the first electrode surface of the radiation detection element and the conductive sheet is a low-elasticity conductive adhesive. And

  With this configuration, the transmission of stress from one of the conductive sheet and the first electrode surface to the other can be avoided by this configuration, and deformation and breakage of these can be prevented.

  In the present invention, a conductive sheet is bonded to the first electrode surface of the radiation detection element via a conductive adhesive, and a high voltage from the substrate can be applied to the first electrode surface via the conductive sheet. By doing so, the electrical connection work between the first electrode surface and the substrate is simplified. Further, the conductive sheet can be protected from the destruction and scientific alteration of the first electrode surface due to a mechanical impact from the outside, and the heat of the integrated circuit element can be radiated to the outside.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a front view conceptually showing a radiation detector according to an embodiment of the present invention. In the figure, the radiation detector R has a plurality of (in this case, four) radiation detection elements 21 arranged without gaps on a substrate 22 having an electric circuit (conductive pattern) via an adhesive having a low elastic modulus. Made of glued ones.

  A first electrode surface 23 and a second electrode surface of the plating layer are provided on both upper and lower surfaces of these radiation detection elements 21.

  In addition, a conductive sheet 24 is bonded on the first electrode surface 23 with a low elastic adhesive so as to cover substantially the entire radiation detecting element 21. One end portion of the conductive sheet 24 protruding from the substrate 22 is bonded to a connection terminal 25 for applying a high voltage provided on the substrate 22 side by a conductive adhesive.

  Note that the conductive sheet 24 has a size within the region of each radiation detection element (or equivalent to this region) except at one end portion that protrudes from the substrate 22.

  In such a radiation detector R, since there is no need to provide a conventional electrode pad on the substrate 22, a dead space where radiation cannot be detected cannot be formed on the substrate 22. For this reason, similar radiation detectors R can be arranged in an array in three directions without gaps. As a result, the area where radiation can be detected at a time can be increased, and the resolution of the radiation image can be improved.

  Furthermore, since it is not necessary to provide a conventional electrode pad on the substrate 22, the conventional process of connecting one wire at a time for each radiation detection element 21 can be omitted. Therefore, the manufacturing efficiency of the device can be improved.

  Further, since the conductive sheet 24 is connected to the first electrode surface 23 of the radiation detecting element using a low elastic modulus conductive adhesive, the conductive sheet 24 is deformed or damaged by the stress caused by the adhesive. Can be prevented.

  In addition, since the contact area between the conductive sheet 24 and the first electrode surface 23 is increased, a high voltage can be uniformly applied to each radiation detection element 21 and charge collection characteristics are improved.

  Since the conductive sheet 24 covers substantially the entire first electrode surface 23, the first electrode surface 23 is damaged by a mechanical impact received from the outside, or the radiation detection element 21 is damaged due to chemical alteration. Can be avoided in advance.

  2 to 5 are plan views of a radiation detector R showing modifications of the conductive sheet 24. FIG. First, FIG. 2 is one in which two slits 26 as through holes are inserted in one side portion (left side portion in the figure) of the conductive sheet 24, and FIG. One slit 27 is inserted in each of the left and right sides in the figure.

  4 is a diagram in which four slits 28 are inserted in the inner region of the conductive sheet 24, and FIG. 5 is a diagram in which a round hole 29 as a through hole is inserted in the inner region of the conductive sheet 24. is there.

  Instead of these slits 26 and slits 28 and round holes 29, incisions may be made.

  The slits 26 to 28 and the round hole 29 are arranged not in the region of the radiation detection element 21 but in a part corresponding to the part where the radiation detection element 21 is adjacent. Thereby, the stress applied to the conductive sheet 24 can be divided for each radiation detection element 21.

  As described above, by providing the slits 26 to the slits 28 and the round holes 29 in the conductive sheet 24, the conductive sheet 24 receives the stress due to the adhesive, the mechanical stress from the outside, or the thermal stress. It is possible to prevent bending or breakage.

  FIG. 6 is a side view showing the radiological image detection apparatus of the present invention. The radiological image detection apparatus S includes a plurality of (here, four) radiological image detection modules M installed on a substrate 32.

  Among these, the radiation image detection module M includes a radiation detection element 31 (corresponding to the radiation detection element 21 in FIG. 1) 31 that is a compound semiconductor of CdTe or CdZnTe, and an integrated circuit element for processing a radiation detection signal. 33 is electrically connected.

  The radiation detection element 31 has a top electrode as a first electrode surface (corresponding to the first electrode surface 23 in FIG. 1) on the top surface and a bottom electrode as a second electrode surface on the bottom surface.

  Among these, the second electrode surface is divided into a plurality of strip electrodes or pixel electrodes as described later. For this reason, it functions to output the radiation detection signal detected by the radiation detection element 31 in strip-shaped electrode units or pixel-shaped electrode units.

  Further, the integrated circuit element 33 calculates (counts) the number of radiations (radiation dose) based on the radiation detection signal transmitted via the strip-like electrode or the pixel-like electrode, and forms a radiation image as necessary. Perform necessary signal processing.

  On the upper surface of the integrated circuit element 33, there are provided a plurality of electrode pads for inputting the radiation detection signal in strip-like electrode units or pixel-like electrode units.

  The corresponding ones of the strip-like electrode or pixel-like electrode on the radiation detection element 31 side and the electrode pad on the integrated circuit element 33 side are electrically and mechanically connected by a bump 34.

  The substrate 32 is provided with input electrode pads corresponding to the output electrode pads provided on the integrated circuit element 33, and these corresponding ones are electrically and mechanically connected by the bumps 35. The substrate 32 also functions to output the output signal of the integrated circuit element 33 to a subsequent signal processing circuit (not shown) for image formation processing or the like.

  On the other hand, a single conductive sheet 37 is bonded to the upper surface electrode of the radiation detecting element 31 via a low elastic conductive adhesive 36.

  Due to the low elastic modulus of the conductive adhesive 36, the influence of the stress generated by the conductive adhesive 36 on the conductive sheet 37 and the first electrode surface is suppressed, and contact with each radiation detection element 31 is achieved. The area can be increased. In addition, a high voltage can be uniformly supplied to these radiation detection elements 31, and the charge collection characteristics can be improved.

  One end surface of the conductive sheet 37 protrudes from the radiation image detection module M, and this one end portion is a connection terminal for high voltage application provided on the substrate 32 (corresponding to the connection terminal 25 in FIGS. 2 to 5). 38 is electrically connected via a conductive adhesive 39. The conductive sheet 37 corresponds to the conductive sheet 24 shown in FIG.

  In the radiation image detection apparatus S having such a configuration, a high voltage can be applied from the substrate 32 side to all of the plurality of radiation detection elements 31 by the single conductive sheet 37. For this reason, the process of connecting a wire from the radiation detection element 31 to several electrode pads like the past can be omitted.

  In addition, with the omission of the electrode pad, it is possible to eliminate a radiation detection insensitive area (dead space).

  Therefore, the resolution of the radiation detection image obtained by the plurality of radiation image detection modules M can be increased, and the apparatus can be miniaturized.

  FIG. 7 is a pattern example of the second electrode surface (lower surface electrode) of the radiation detection element 31 constituting the radiation image detection module M shown in FIG.

  FIG. 7A shows a case where the entire second electrode surface (lower electrode) is formed of a single electrode. FIG. 7B shows a lower electrode 40 and a guard ring electrode 41 arranged around the lower electrode 40.

  FIGS. 7C and 7D show still another pattern example in which the lower surface electrode 40 and the guard ring electrode 41 are arranged around the lower surface electrode 40. Among these, FIG. 7 (c) shows that the bottom electrode 40 is divided into strips and formed into strip electrodes 40a, and FIG. 7 (d) shows that the bottom electrode 40 is divided into a grid. The pixel electrode 40b is formed.

  Therefore, the radiation detection information can be taken out from the radiation detection element 31 with the resolution corresponding to the number of divisions and the electrode size in units divided into strips or pixels in this way.

  FIG. 8 is a block diagram showing a radiological image detection system having the radiological image detection apparatus S.

In the figure, 50 is an object to be imaged, 51 is a radiation source, 53 is a radiation source 51.
X-rays, gamma rays, and other radiations generated at, and 54 are transmitted radiation attenuated through the object 50 and enter the radiation image detection apparatus S of the present invention.

  Reference numeral 52 denotes an image processing display device having a function of processing a signal transmitted from the radiation image detection device S to image, store and display the signal.

  In the radiological image detection apparatus S, pixel position information (X-axis and Y-axis information) and density information (Z-axis information) are obtained through conversion of the transmitted radiation 54 including the internal configuration information of the object 50 into an electrical signal and analog-digital conversion. Information) is obtained as described above, and each piece of information (digital signal) is sent to the image processing display device 52.

  In this image processing display device 52, based on the pixel position information and shading information, the radiation amount measured for all the pixels is configured as a monochromatic density difference or hue difference, and an image is measured. The distribution state of the internal components of can be imaged.

  As described above, the radiation detector and the radiation image detection apparatus according to the present invention can omit the work of wire-connecting the first electrode surface and the electrode pad as in the related art, and can be mechanically applied from the outside. The radiation having the radiation detection element on the substrate has the effect that the destruction of the first electrode surface and chemical alteration due to the impact can be avoided, and further the heat of the integrated circuit element can be radiated to the outside. Useful for detectors and radiation detection devices.

It is a top view which shows notionally the radiation detector by embodiment of this invention. It is a top view which shows the other application example of the radiation detector by embodiment of this invention. It is a top view which shows the other application example of the radiation detector by embodiment of this invention. It is a top view which shows the other application example of the radiation detector by embodiment of this invention. It is a top view which shows the other application example of the radiation detector by embodiment of this invention. It is a side view which shows the radiographic image detection apparatus by embodiment of this invention. It is process drawing which shows the formation procedure of the 2nd electrode surface of the radiation detection element in FIG. It is a block diagram which shows the radiographic image display apparatus containing the radiographic image detection apparatus of this invention. It is a top view which shows the conventional radiation detector notionally.

Explanation of symbols

21 Radiation detection element 22 Substrate 23 Upper surface electrode (first electrode surface)
24 conductive sheet 25 connection terminal for applying high voltage 26, 27, 28 slit (through hole)
29 Round hole (through hole)
31 Radiation Detection Element 32 Substrate 33 Integrated Circuit Element 36 Low Elasticity Conductive Adhesive 37 Conductive Sheet 40 Bottom Electrode (Second Electrode Surface)
R radiation detector S radiation image detection device M radiation image detection module

Claims (13)

A radiation detection element having a first electrode surface and a second electrode surface located on the opposite side of the first electrode surface is mounted on a substrate, and is electrically conductive on the first electrode surface of the radiation detection element. A radiation detector, wherein a conductive sheet is bonded via an adhesive, and the first electrode surface is electrically connected to the substrate via the conductive sheet. A plurality of the radiation detection elements are mounted on the substrate in a one-dimensional or two-dimensional array, and the first electrode surfaces of all the radiation detection elements are electrically connected to the substrate via the conductive sheet. The radiation detector according to claim 1, wherein the radiation detector is connected to the radiation detector. The radiation detector according to claim 1, wherein the radiation detection element is CdTe or CdZnTe. The radiation detector according to any one of claims 1 to 3, wherein a size of the conductive sheet is equal to or smaller than a size of the radiation detection element. The radiation detector according to claim 2, wherein a size of the conductive sheet is equal to or smaller than a size of the plurality of radiation detection elements arranged in an array. The radiation detector according to claim 1, wherein the conductive sheet has a cut or a through hole. 8. The conductive adhesive for bonding the first electrode surface of the radiation detection element and the conductive sheet is a low-elastic conductive adhesive. A radiation detector according to claim 1. A radiation detection element having a first electrode surface and a second electrode surface positioned on the opposite side of the first electrode surface, and an integrated circuit element having an integrated circuit are interposed via the second electrode surface. A radiation image detection module that is electrically connected is mounted on a substrate, and a conductive sheet is connected to the first electrode surface of the radiation detection element in the radiation image detection module via a conductive adhesive. A radiological image detection apparatus, wherein the substrate and the radiographic image detection module are electrically connected via a sheet. A plurality of the radiation image detection modules are mounted on a substrate in a one-dimensional or two-dimensional array, and all the radiation image detection modules are electrically connected to the substrate by the conductive sheet. The radiographic image detection apparatus according to claim 8. The radiological image detection apparatus according to claim 8, wherein the radiation detection element is CdTe or CdZnTe. The radiographic image detection apparatus according to claim 8, wherein a size of the conductive sheet is equal to or smaller than a size of the radiation detection element. The radiographic image detection apparatus according to claim 9, wherein a size of the conductive sheet is equal to or smaller than a size of the plurality of radiographic image detection modules arranged in an array. 13. The conductive adhesive for bonding the first electrode surface of the radiation detection element and the conductive sheet is a low-elastic conductive adhesive. A radiological image detection apparatus according to claim 1.

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