JP2016011958A - Radiation imaging device, radiation imaging system, and manufacturing method of radiation imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation imaging device having a laminate structure in which an imaging element is sandwiched by a scintillator and a base, and in which the imaging element or the scintillator can be separated under a mechanically stable state of the imaging element.SOLUTION: The radiation imaging device includes a base 2, an imaging element 4, a scintillator 6, a first heat-separation type adhesive member 3 having a property of degrading of its adhesive strength by heating and for fixing the base 2 and the imaging element 4, and a second heat-separation type adhesive member 5 having an adhesive strength degrading temperature being the same as the first heat-separation type adhesive member 3 and for fixing the imaging element 4 and the scintillator 6. A heat transfer amount of the base 2 per unit time period and a heat transfer amount of the scintillator 6 per unit time period are different from each other.

Description

  The present invention relates to a radiation imaging apparatus for detecting radiation such as X-rays, a radiation imaging system, and a method for manufacturing the radiation imaging apparatus, and more particularly to a radiation imaging apparatus used for a medical image diagnostic apparatus, a nondestructive inspection apparatus, an analysis apparatus, and the like. .

  Currently, single crystal semiconductor wafers that are generally distributed are smaller than glass substrates. Therefore, in order to form a radiation imaging apparatus with a large area using a single crystal semiconductor wafer, the single crystal semiconductor wafer on which the detection elements are formed is divided to form a plurality of imaging element chips so that a desired area is obtained. A number of image sensor chips are arranged.

  In Patent Document 1, for cost reduction, before bonding a chip-like image pickup device to a base substrate that is a part of the apparatus, inspection of the image pickup device and replacement of the image pickup device in which a defect is found are performed. It is described to do. And it describes that the image sensor and the base substrate are bonded and fixed after inspection and replacement. In addition, it is described that a scintillator that converts radiation into light in a wavelength band that can be sensed by the image sensor is adhered and disposed on the side opposite to the base substrate (base) of the image sensor.

  Patent Document 2 discloses a double-sided pressure-sensitive adhesive sheet used for fixing a liquid crystal display module unit and a backlight unit for rework in a liquid crystal display device, and a heat-peelable pressure-sensitive adhesive layer containing thermally expandable particles is used. Have been described.

JP 2002-139568 A JP 2008-144116 A

  However, in the method of Patent Document 1, it is difficult to replace an image sensor or scintillator in which a defect is found by inspection after the image sensor and the base substrate are bonded or after the image sensor and the scintillator are bonded. For example, when an image sensor having a defect in a radiation detection apparatus having a plurality of image sensors is peeled off from the base substrate, there is a possibility that an external force is applied to the image sensor not having a defect and the image sensor is cracked. In addition, there is a possibility that the characteristics of the image pickup device having no defect may be deteriorated by the solvent for dissolving the adhesive. Further, a case is considered in which no defect is detected in the image sensor in the inspection process performed after the image sensor is bonded to the base substrate, and any defect is detected in the test process performed after the scintillator is bonded to the image sensor. In this case, since it is considered that only the scintillator has a defect, it is necessary to peel the scintillator from the image sensor and replace the scintillator, but it is not necessary to peel the base substrate from the image sensor. In this way, in the radiation imaging apparatus having a stacked configuration in which the imaging element is sandwiched between the scintillator and the base, peeling between the scintillator and the imaging element and peeling between the base and the imaging element are performed simultaneously. It may be desirable not to. If the separation between the scintillator and the image sensor and the separation between the base and the image sensor are performed at the same time, the image sensor will be in a mechanically unstable state where nothing is fixed. There is a possibility that the image sensor moves during peeling and collides with something to break the image sensor.

  Patent Document 2 is a simple separation between a liquid crystal display module unit and a backlight unit with respect to a liquid crystal display device in which the liquid crystal display module unit and the backlight unit are fixed one-to-one. Separation is not assumed in an apparatus having a multi-layer structure composed of three or more layers.

  In view of the above problems, the present invention is capable of peeling an image sensor or a scintillator in a mechanically stable state in the radiation imaging apparatus having a stacked configuration in which the image sensor is sandwiched between a scintillator and a base. An object of the present invention is to provide a possible radiation imaging apparatus.

  In order to achieve the above object, the radiation imaging apparatus of the present invention has a base, an imaging element, a scintillator, and a property that the adhesive force is reduced by particle heating, and fixes the base and the imaging element. The first heat-peelable adhesive member for fixing the image sensor and the scintillator and the second heat-peelable adhesive for fixing the image pickup device and the scintillator are equal in temperature to the first heat-peelable adhesive member. And a heat conduction amount per unit time of the base is different from a heat conduction amount per unit time of the scintillator.

  The radiation imaging system of the present invention includes the radiation imaging apparatus and signal processing means for processing a signal from the radiation imaging apparatus.

  In the method for manufacturing a radiation imaging apparatus of the present invention, the imaging element is fixed to a base via a first heat-peelable adhesive member having a property that the adhesive force is reduced by particle heating, and the first heating is performed. A fixing step of fixing to a scintillator having a different heat conductivity per unit time from the base through a second heat-peelable adhesive member having the same temperature at which the adhesive strength decreases with the peelable adhesive member; An inspection step of inspecting the fixed imaging device, and the base when the imaging device or the scintillator is determined to have a defect by inspection in the inspection step The first heat-peelable adhesive member is heated via the scintillator and the second heat-peelable adhesive member is heated via the scintillator. The heat transfer amount per unit time is large and the image sensor is separated, and the base and the scintillator have a small heat transfer amount per unit time between the image sensor and the other. The method further includes a peeling step in which the peeling is not performed.

  According to the present invention, in a radiation imaging apparatus having a stacked configuration in which an imaging element is sandwiched between a scintillator and a base, separation can be performed separately between the imaging element and the scintillator and between the imaging element and the base. Therefore, in a radiation imaging apparatus having a stacked configuration in which an imaging element is sandwiched between a scintillator and a base, a radiation imaging apparatus capable of peeling the imaging element or scintillator in a mechanically stable state is obtained. Is possible.

It is the top view and sectional drawing of a radiation imaging device concerning a 1st embodiment of the present invention. It is sectional drawing, a top view, and a temperature-expansion magnification characteristic view for demonstrating the heat-peelable adhesive member of this invention. It is a figure explaining the manufacturing process of the radiation imaging device which concerns on the 1st Embodiment of this invention. It is a figure explaining the process of peeling the base which concerns on the 1st Embodiment of this invention. It is a figure explaining the process of peeling the scintillator which concerns on the 1st Embodiment of this invention. It is the top view and sectional drawing of the radiation imaging device which concern on the 2nd Embodiment of this invention. It is the top view and sectional drawing of the radiation imaging device which concern on the 2nd Embodiment of this invention. It is the figure which showed the example of application to the radiation imaging system of the radiation imaging device of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present invention, radiation is a beam having energy of the same degree or more, for example, X-rays in addition to α-rays, β-rays, γ-rays, etc., which are beams formed by particles (including photons) emitted by radiation decay , Particle beams, cosmic rays, etc. are also included. Moreover, in this invention, light contains visible light and infrared rays.

(First embodiment)
Below, the 1st Embodiment of this invention is described using Fig.1 (a)-(c). 1A is a plan view of main components of the radiation imaging apparatus according to the first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along the line AA ′ in FIG. FIG. 1C is a cross-sectional view in which a part of the cross section corresponding to the AA ′ position in FIG. 1A of the entire radiation imaging apparatus is enlarged.

  As shown in FIGS. 1A and 1B, a radiation imaging apparatus 1 includes a base 2 and four imaging elements 4 fixed on the base 2 via a first heat-peelable adhesive member 3. And a scintillator 6 fixed on the image pickup element 4 via a second heat-peelable adhesive member 5. A wiring substrate 10 for transferring a signal between the image sensor and an external circuit (not shown) is fixed to the image sensor 4. The four image sensors 4 are arranged on the base 2 with a space in order to reduce the electromechanical influence when the image sensors 4 come into contact with each other. Note that the number of the image pickup devices 4 fixed to the base 2 is not limited to four, and one or more image pickup devices 4 may be arranged. The image sensor 4 has a plurality of pixels each having a switch element and a sensor unit. For example, a CMOS sensor, a CCD sensor, an PIN sensor using amorphous silicon (hereinafter abbreviated as a-Si), an a-Si sensor having a pixel composed of a MIS sensor and TFT, and an SOI (Silicon on Insulator). Sensors and the like. As the wiring board 10, a flexible wiring board (FPC) is preferably used, but a rigid wiring board can be used. The scintillator 6 has at least a scintillator layer 8 that converts radiation such as X-rays into light that can be sensed by the imaging device 4. As shown in FIG. 1B, the scintillator 6 further includes a substrate 7 for supporting the scintillator layer 8 and a protective layer 9 for protecting the scintillator layer 8 from moisture and impact from the outside. Is desirable. The substrate 7 is made of amorphous carbon (a-C) (thermal conductivity = 5 to 8 (W / (m · K))), aluminum (Al) (same as 237 (W / (m · K))), resin. (Same as 0.1 to 0.2 (W / (m · K))) or the like is used. The scintillator layer 8 has columnar crystals such as CsI: Tl (thermal conductivity of CsI = 1 (W / (m · K))) or GOS that converts radiation such as X-rays into light that can be sensed by the image sensor 4. A particulate crystal such as is used. For the protective layer 9, polyparaxylylene, hot melt resin, or the like is used. For the base 2, Al (thermal conductivity = 237 (W / (m · K))) can be used. However, glass (same as above = 1 (W / (m · K))), resin such as acrylic (same as 0.2 (W / (m · K))), various ceramics (same as 3 to 170). (W / (m · K))), metal (same as above = 15 to 427 (W / (m · K))) and the like can be used as appropriate. In addition, detailed description regarding the 1st heat peelable adhesive member 3, the 2nd heat peelable adhesive member 5, the scintillator 6, and the base 2 used for this invention is mentioned later.

  Further, as shown in FIG. 1C, a sealing member 11 is disposed between the base 2 and the scintillator 6 around the radiation imaging apparatus 1 in order to reduce intrusion of moisture and the like from the outside. Has been. The imaging element 4 is sealed by being surrounded by the sealing member 11, and the wiring substrate 10 is disposed so as to penetrate the sealing member 11. Here, the sealing member 11 is made of an acrylic resin, an epoxy resin, a silicone resin, or the like, and is preferably a black resin that absorbs light. This is because, when the base 2 transmits light having a wavelength that can be sensed by the image sensor 4, the light is prevented from entering the image sensor 4 as stray light, and deterioration in image quality is reduced. The radiation imaging apparatus 1 of this embodiment includes an integrated circuit 12 that processes a signal output from the imaging element 4 via the wiring board 10. The radiation imaging apparatus 1 further includes a base 2, a plurality of imaging elements 4, a scintillator 6, and a housing 15 that houses the integrated circuit 12. A buffer member 13 is disposed between the sealing member 11 and the housing 15, and a buffer member 14 is disposed between the scintillator 6 and the housing 15. As the buffer member 13, it is preferable to use, for example, a black resin that absorbs light in a wavelength band that can be sensed by the image sensor 4. Thereby, it is possible to reduce the stray light in the housing 15 from entering the image sensor 4 and to reduce the deterioration of the image quality.

  This heat-peelable adhesive member is composed of an adhesive and a foaming agent containing thermally expandable particles. The first heat-peelable adhesive member 3 enables fixing of the base 2 and the plurality of image pickup devices 4 and peeling between the base 2 and the image pickup device 4 during repair. Arranged to make it easier. The second heat-peelable adhesive member 5 can fix the plurality of image pickup devices 4 and the scintillator 6 and peel off the scintillator 6 and the image pickup device 4 during repair. The image pickup device 4 or the scintillator 6 Is arranged to facilitate replacement. The first heat-peelable adhesive member 3 and the second heat-peelable adhesive member 5 are heat-reactive types, and have a property that the adhesive force decreases in response to heat at a predetermined temperature or higher. The first heat-peelable adhesive member 3 and the second heat-peelable adhesive member 5 have the same temperature at which the adhesive force decreases.

  In the first heat-peelable adhesive member 3 and the second heat-peelable adhesive member 5, the thermally expandable particles as the foaming agent contained are foamed and / or expanded by heating, and the surface of the heat-peelable adhesive member is uneven. Is formed, the adhesion area with the adherend is reduced, and the adhesiveness is lowered. Therefore, it is possible to safely peel the imaging element 4 from the scintillator 6 and the base 2. Here, the thickness of the heat-peelable adhesive member and the size of the heat-expandable particles are suitably set so that the above mechanism appears.

  As the adhesive, an appropriate adhesive such as a rubber adhesive, an acrylic adhesive, a styrene / conjugated diene block copolymer adhesive, or a silicone adhesive can be used, and an ultraviolet curable adhesive can also be used. . The adhesive may be blended with appropriate additives such as a crosslinking agent, a tackifier, a plasticizer, a filler, and an anti-aging agent as necessary. More specifically, for example, rubber adhesives based on natural rubber and various synthetic rubbers as a base polymer, methyl group, ethyl group, propyl group, butyl group, 2-ethylhexyl group, isooctyl group, isononyl group, isodecyl group, Acrylic acid such as acrylic acid or methacrylic acid having an alkyl group having 20 or less carbon atoms, usually dodecyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group Alkyl esters, esters such as acrylic acid and methacrylic acid having functional group-containing groups such as hydroxyethyl group, hydroxypropyl group, glycidyl group, acrylic acid, methacrylic acid, itaconic acid, N-methylolacrylamide, acrylonitrile, methacrylonitrile , Vinyl acetate, Ren, isoprene, butadiene, isobutylene, and acrylic adhesives acrylic polymer as a base polymer can be mentioned, and the like components vinyl ether. The adhesive is appropriately selected and used according to the purpose of use such as the adhesive strength to the adherend, and the heat-peelable adhesive member that expands by heating can be formed by blending a foaming agent with the adhesive.

  Various foaming agents that can achieve the above-described purpose can be used. Therefore, for example, a foaming agent that foams and / or expands at a temperature higher than the adhesive processing temperature of the adhesive is used. Examples of the foaming agent that can be used include decomposition-type inorganic foaming agents such as ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, and azides. Organic foaming agents such as azo compounds can also be used. Examples include fluorinated alkanes such as trichloromonofluoromethane and dichloromonofluoromethane, azo compounds such as azobisisobutyronitrile, azodicarbonamide, barium azodicarboxylate, paratoluenesulfonyl hydrazide, diphenylsulfone- Hydrazine compounds such as 3,3′-disulfonylhydrazide, 4,4′-oxybis (benzenesulfonylhydrazide), allylbis (sulfonylhydrazide), ρ-toluylenesulfonyl semicarbazide and 4,4′-oxybis (benzenesulfonyl semicarbazide) Semicarbazide compounds such as 5-morpholyl-1,2,3,4-thiatriazole, N, N′-dinitrosopentamethylenetetramine and N, N′-dimethyl-N N'- dinitrosoterephthalamide such as N- nitroso compounds, and other low-boiling compounds.

  Furthermore, thermally expandable particles in which an appropriate material that easily gasifies and exhibits thermal expansibility, such as isobutane, propane, and pentane, is encapsulated in a shell-forming material by a coacervation method or an interfacial polymerization method is also used as a foaming agent. be able to. The average particle diameter of the thermally expandable particles used is generally 5 to 50 μm. However, finer thermally expandable particles can also be used. In addition, the particle size of the thermally expandable particles of the present invention is represented by a test sieve opening measured by a sieving method, a Stokes equivalent diameter by a sedimentation method, or a circle equivalent diameter by a microscopic method. And the equivalent sphere diameter by the light scattering method and the equivalent sphere value by the electrical resistance test method. The average particle diameter of the thermally expandable particles of the present invention is a median diameter using the above particle diameter.

  Examples of the shell-forming substance that forms thermally expandable particles include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. However, in the present invention, the shell forming material may be made of a material that is thermally meltable and expands due to expansion of the thermally expandable material and becomes thin, or a material that breaks down due to thermal expansion.

  The second heat-peelable adhesive member 5 is light transmissive because the imaging element 4 needs to sense light emitted from the scintillator 6. When the light from the scintillator 6 is visible light, it is necessary that the transmittance of visible light is high, and it is preferable that the transmittance is 90% or more particularly at a wavelength at which the scintillator layer 8 shows the maximum light emission amount. The thickness of the second heat-peelable adhesive member 5 is preferably 200 μm or less, more preferably 50 μm or less, and more preferably from the pixel pitch because the sharpness (MTF) indicating the image clarity decreases as the thickness increases. Small is preferable. However, since adhesive force is also necessary, it is preferably 1 μm or more and 50 μm or less for practical use. The average particle diameter of the thermally expandable particles contained in the second heat peelable adhesive member 5 is desirably smaller than the pixel pitch P. When the average particle diameter of the thermally expandable particles is smaller than the pixel pitch P of the image sensor 4, the light scattered by the thermally expandable particles does not spread greatly. Therefore, it is possible to suppress a decrease in sharpness (MTF) of the obtained image. Here, the imaging element 4 includes a plurality of pixels including photoelectric conversion elements and switching elements arranged in a matrix, and a pitch at which the plurality of pixels are arranged is a pixel pitch P.

  2A and 2B are cross-sectional views of the first or second heat-peelable adhesive member before use. As shown in FIG. 2A, both surfaces of the first heat-peelable adhesive member 3 are covered with separators 31 and 32, and the separators 31 and 32 are peeled off when used. Similarly, as shown in FIG. 2 (b), both surfaces of the second heat-peelable adhesive member 5 are covered with separators 51 and 52, and the separators 51 and 52 are peeled off in use.

  Next, the mechanism for reducing the adhesive force due to heating of the heat-peelable adhesive member of the present invention will be described with reference to FIG. Here, a heat-peelable adhesive member using thermally expandable particles is described as an example. The left side of FIG. 2C is a plan view of the heat-peelable adhesive member before heating, and the right side is after heating. It is a top view of this heat-peelable adhesive member. After heating, a large number of large irregularities are generated after heating as compared to the surface of the first heat-peelable adhesive member 3 before heating, and the heat-peelable adhesive member 30 has a reduced adhesive force. The same applies to the second heat-peelable adhesive member 5.

  Next, the characteristic of the expansion ratio with respect to the temperature of the thermally expandable particles contained in the first and second heat peelable adhesive members will be described with reference to FIG. Here, S in FIG. 2D is a temperature at which the volume expansion of the thermally expandable particles starts (expansion start temperature), and M is a temperature at which the volume of the thermally expandable particles becomes maximum (maximum expansion temperature). . That is, the first heat-peelable adhesive member 3 and the second heat-peelable adhesive member 5 have thermally expandable particles having the same expansion start temperature and / or maximum expansion temperature. However, what does not use the thermally expandable particles as the foaming agent may be any one that has the same expansion start temperature of the foaming agent and the same material and adhesive composition of the foaming agent. In other words, the first heat-peelable adhesive member 3 and the second heat-peelable adhesive member 5 of the present invention have the same temperature at which the adhesive force is reduced. Here, as a typical example, the mechanism of a decrease in adhesive force due to heating of a heat-peelable adhesive member having thermally expandable particles will be described below.

  As the heat-expandable particles are heated, the shell-forming material starts to soften, and at the same time, the easily gasified material contained therein begins to foam and the internal pressure increases, so that the particles expand. The temperature at this time is the expansion start temperature S. When expanded to the maximum volume, the internal pressure and the tension / external pressure of the shell-forming substance are balanced to maintain the expanded state. The temperature at this time is the maximum expansion temperature M. If the heating is further continued, the gas generated by foaming permeates and diffuses the thin shell-forming substance, so that the tension and the external pressure of the shell-forming substance prevail over the internal pressure, causing contraction. By using such heat-expandable particles for the heat-peelable adhesive member, the heat-expandable particles in the adhesive expand by heating, and as described with reference to FIG. As a result, the adhesion area with the adherend is reduced and the adhesiveness is lowered.

  The first heat-peelable adhesive member 3 and the second heat-peelable adhesive member 5 have the same temperature at which the adhesive force is reduced by heating. Here, the temperature at which the adhesive force is reduced by heating is equal to the temperature at which the object is peeled from the adherend while the same force is applied to the object to be peeled in the same direction as the first heat peelability. It means that the adhesive member 3 and the second heat-peelable adhesive member 5 are equal. For example, in the peel test method defined in Japanese Industrial Standard JIS Z0237, the temperature at which the object is peeled from the adherend is equal between the first heat peelable adhesive member 3 and the second heat peelable adhesive member 5. Point to. In addition, it is preferable that the temperature at which the adhesive strength is reduced by heating the first heat-peelable adhesive member 3 and the second heat-peelable adhesive member 5 is not more than the temperature at which the characteristics of the scintillator 6 change. The temperature at which the characteristics of the scintillator 6 change is the lowest temperature among the activation temperature of the scintillator layer 8, the glass transition point of the substrate 7, and the glass transition point of the protective layer 9.

In the present invention, the amount of heat transfer per unit time of the scintillator 6 and the base 2 in contact with the first and second heat-peelable adhesive members is important. Here, the amount of heat transfer per unit time is the amount of heat transferred per unit time. The thermal conductivity is k (J / s · m · K), the temperature difference between both ends of the member is ΔT (K), the thickness of the member is L (m), and the contact area with the heat transfer member is S (m ^2). ) If the heating time is t (s), the heat quantity Qt (J) is expressed by the following equation.

Qt = k × S × ΔT × t / L (1)
Here, since it can be assumed that the temperature difference ΔT between the both ends of the base 2 and the scintillator 6 that are the target objects is equal and the heating time t is also equal, the heat transfer amount Q per unit time can be expressed by the following equation: Indicated by

Q = k × S / L (2)
Therefore, assuming that the areas where the members constituting the scintillator 6 and the base 2 are in contact with each other are approximately the same, the amount of heat transfer per unit time of each member is determined by the thickness of the member. It can be defined by the divided value.

  For example, when a-C having a thermal conductivity of 5 (W / (m · K)) and a thickness of 1 mm is used as the substrate 7, the heat transfer amount of the substrate 7 per unit time is 5,000 (J ) Similarly, when CsI: Tl having a thickness of 0.55 mm is used as the scintillator layer 8, the heat transfer amount of the scintillator layer per unit time is 1,818 (J). Further, when polyparaxylylene having a thickness of 0.0024 mm is used as the protective layer 9, since there is a portion in contact with the substrate 7 and a portion in contact with the scintillator layer 8, the thickness becomes 0.0048 mm in total. The heat transfer amount of the protective layer 9 per unit time is 4,167 (J). Therefore, the heat transfer amount per unit time of the entire scintillator 6 is 10,985 (J).

  On the other hand, when Al having a thickness of 2 mm, for example, is used as the base 2, the heat transfer amount of the base 2 per unit time is 118,500 (J). That is, the amount of heat transfer per unit time of the scintillator 6 is greatly different from about 1/10 or less of the amount of heat transfer per unit time of the base 2.

  For example, when glass having a thickness of 2 mm is used as the base 2, the heat transfer amount of the base 2 per unit time is 500 (J). That is, the amount of heat transfer per unit time of the scintillator 6 is greatly different from 10 times or more of the amount of heat transfer per unit time of the base 2.

  In such cases, when heated simultaneously from the base 2 side and the scintillator 6 side in a thermostatic bath, the amount of heat conducted to the first heat peelable adhesive member 3 and the second heat peelable adhesive member 5 are conducted. There is a big difference in the amount of heat generated. If there is a large difference in the amount of heat conducted, the adhesive strength between the first heat-peelable adhesive member 3 and the second heat-peelable adhesive member 5 having the same temperature at which the adhesive force is reduced by heating is equal. The timing at which it drops below the peelable adhesive force is different. Therefore, peeling between the scintillator 6 and the image sensor 4 and peeling between the base 2 and the image sensor 4 are performed separately. Thereby, even when the imaging element 4 is peeled off from one of the base 2 and the scintillator 6, the imaging element 4 is fixed to the other of the base 2 and the scintillator 6. The operation | work which replaces | exchanges the element 4 can be performed. This results in a mechanically unstable state in which the image sensor is not fixed to anything during the peeling process, which causes the image sensor to move and collide with something mechanically during the peeling operation. Can be prevented. This is particularly suitable when a plurality of image sensors 4 are provided. Further, when only the scintillator 6 has a defect, it is possible to peel only the scintillator 6 without peeling the base 2 from the image pickup device 4. Therefore, in the radiation imaging apparatus in which the imaging element 4 is sandwiched between the scintillator 6 and the base 2, the imaging element 4 or the scintillator 6 can be peeled off while the imaging element 4 is mechanically stable.

  Next, the peeling process which peels the image pick-up element 4 performed by this invention is demonstrated. Here, a description will be given in a form in which a-C (heat transfer amount per unit time = 5,000 (J)) is used for the substrate 7 and Al (118 = 500 (J)) is used for the base 2. . In the present embodiment, the product name “Riva Alpha No. 3193MS” manufactured by Nitto Denko Corporation was used as the first and second heat-peelable adhesive members.

  First, the radiation imaging apparatus including the imaging element 4 that needs to be peeled off is put into a thermostat and heated. In the thermostat, the same force is applied to the scintillator 6 and the base 2 in a direction perpendicular to the image sensor 4 and away from the image sensor. The base 2 made of Al has a larger amount of heat transfer per unit time than the scintillator 6 having the substrate 7 made of aC, and the heat is transmitted to the first heat-peelable adhesive member 3 through the base 2, Expansion starts at the expansion start temperature S in FIG. 2D, and a decrease in the adhesive strength of the first heat-peelable adhesive member 3 starts. Furthermore, heat is applied to the first heat-peelable adhesive 3 and reaches the maximum expansion temperature M at which the adhesive force of the first heat-peelable adhesive member 3 is most reduced. Due to the force applied to the base 2, the adhesive force of the first heat-peelable adhesive member 3 is lowered at a temperature higher than the expansion start temperature S, and the base 2 and the image sensor 4 are peeled off. In this case, the heat transfer amount per unit time of the scintillator 6 is preferably 1/10 or less when the heat transfer amount per unit time of the base 2 is 1. Here, the heat is transferred to the second heat-peelable adhesive member 5 through the scintillator 6, but the heat transfer amount per unit time of the scintillator 6 is smaller than the heat transfer amount per unit time of the base 2. Therefore, when the first heat peelable adhesive member 3 reaches the expansion start temperature S or the maximum expansion temperature M, the second heat peelable adhesive member 5 still reaches the expansion start temperature S or the maximum expansion temperature M. Absent. Therefore, the second heat-peelable adhesive member 5 does not have a lower adhesive force than the first heat-peelable adhesive member 3, and the scintillator 6 and the image sensor 4 are not peeled off.

  Thereafter, the second heat peelable adhesive member 5 is heated in a form in which the scintillator 6, the second heat peelable adhesive member 5, and the imaging element 4 are laminated. At this time, the side surface opposite to the scintillator 6 of the image sensor 4 may be adsorbed by the conveying means 21 and heated from the surface of the substrate 7 by a hot plate or the like. Moreover, when using a thermostat, you may heat after returning to room temperature once, and you may perform further heating continuously with previous heating. The heat is transferred to the second heat-peelable adhesive member 5 through the scintillator 6, starts to expand at the expansion start temperature S in FIG. 2D, and starts to decrease the adhesive force of the second heat-peelable adhesive member 5. To do. Furthermore, heat is applied to the second heat-peelable adhesive 5, and the second heat-peelable adhesive member 5 reaches the maximum expansion temperature M at which the adhesive strength is the lowest. Due to the force applied to the scintillator 6, the adhesive force of the second heat-peelable adhesive member 5 is lowered at a temperature higher than the expansion start temperature S, and the scintillator 6 and the image sensor 4 are peeled off.

  As described above, in the present invention, the first heat peelable adhesive member 3 and the second heat peelable adhesive member having the same temperature at which the adhesive force is reduced are used, and the heat transfer amount per unit time is transmitted to the image sensor 4. Different base 2 and scintillator 6 are bonded. Therefore, the timing at which the surface of the base 2 on the first heat-peelable adhesive member 3 side reaches the temperature at which the first heat-peelable adhesive member 3 has reduced adhesive force, and the second heat-peelable of the scintillator 6 The timing at which the surface on the adhesive adhesive member 5 side reaches the temperature at which the second heat-peelable adhesive member 5 decreases in adhesive strength is different. Accordingly, the first heat-peelable adhesive member 3 is heated via the base 2 and the second heat-peelable adhesive member 5 is heated via the scintillator 6, thereby allowing the base 2, the imaging element 4, And the separation between the scintillator 6 and the image sensor 4 can be performed separately. Even when the image pickup device 4 is peeled from one of the base 2 and the scintillator 6, the image pickup device 4 is fixed in the other of the base 2 and the scintillator 6. Can be replaced. This is suitable when at least one of the plurality of image sensors 4 is an image sensor having a defect.

  An embodiment in which aC (heat transfer amount per unit time = 5,000 (J)) is used for the substrate 7 and glass (the same = 500 (J)) is used for the base 2 will be described. In the present embodiment, the product name “Riva Alpha No. 3193MS” manufactured by Nitto Denko Corporation was used as the first and second heat-peelable adhesive members.

  First, the radiation imaging apparatus is put into a thermostat and heated. In the thermostat, the same force is applied to the scintillator 6 and the base 2 in a direction perpendicular to the image sensor 4 and away from the image sensor. The scintillator 6 having the substrate 7 made of aC has a larger heat transfer amount per unit time than the base 2 using glass, and the heat is transmitted to the second heat-peelable adhesive member 5 through the scintillator 6, Expansion starts at the expansion start temperature S in FIG. 2D, and the decrease in the adhesive strength of the second heat-peelable adhesive member 5 begins. Furthermore, heat is applied to the second heat-peelable adhesive 5, and the second heat-peelable adhesive member 5 reaches the maximum expansion temperature M at which the adhesive strength is the lowest. Due to the force applied to the scintillator 6, the adhesive force of the second heat-peelable adhesive member 5 is lowered at a temperature higher than the expansion start temperature S, and the scintillator 6 and the image sensor 4 are peeled off. Here, the heat is transferred to the first heat-peelable adhesive member 3 through the base 2, but the heat transfer amount per unit time of the base 2 is smaller than the heat transfer amount per unit time of the scintillator 6. . Therefore, when the second heat peelable adhesive member 5 reaches the expansion start temperature S or the maximum expansion temperature M, the first heat peelable adhesive member 3 has not yet reached the expansion start temperature S or the maximum expansion temperature M. Absent. Therefore, the first heat-peelable adhesive member 3 has no lower adhesive strength than the second heat-peelable adhesive member 5, and the base 2 and the image sensor 4 are not peeled off. . In this case, the heat transfer amount per unit time of the scintillator 6 is preferably 10 times or more when the heat transfer amount per unit time of the base 2 is 1. Such peeling is suitable when the scintillator 6 has a defect.

  Next, the manufacturing method of the radiation imaging apparatus 1 is demonstrated using FIG. Here, a description will be given in a form in which a-C (heat transfer amount per unit time = 5,000 (J)) is used for the substrate 7 and Al (118 = 500 (J)) is used for the base 2. .

  First, the adsorption process shown in FIG. The image sensor 4 is attracted to the stage 20 by suction so that the arrangement of the image sensors 4 is not disturbed. In the suction process, the image pickup device 4 arranged on the stage 20 is sucked by the transport unit 21.

  Next, the first fixing step shown in FIG. A base 2 is placed on the stage 22. The first heat-peelable adhesive member 3 is disposed on the image sensor 4 adsorbed by the transport means 21. The first heat-peelable adhesive layer 3 is disposed on the image sensor 4 by peeling the separators 31 and 32 from the state shown in FIG. The imaging element 4 is fixed to the base 2 through the first heat-peelable adhesive member 3. Here, the first heat-peelable adhesive member 3 is disposed on the imaging element 4 side, but may be disposed on the base 2 side. However, in the form using a plurality of image sensors, when the first heat-peelable adhesive member 3 is divided and arranged on the image sensor 4 side corresponding to each of the image sensors 4, each of the plurality of image sensors 4 is provided. On the other hand, it is possible to perform the separation separately, which is more preferable. In the present specification, “fixed” means that only the first or second heat-peelable adhesive member 3 is disposed between the base 2 or the scintillator 6 and the imaging element 4, and the base 2 or the scintillator 6 The configuration is not limited to the configuration in which the imaging element 4 is bonded. In addition to such a configuration, another material is further disposed between the base 2 or the scintillator 6 and the imaging device 4 via the other material in addition to the first or second heat-peelable adhesive member 3. It is assumed to include a structure to be bonded. The first fixing process is performed for each of the plurality of image pickup devices 4, and the plurality of image pickup devices 4 are fixed to the base 2 by the first heat-peelable adhesive member 3.

  Next, a first inspection process shown in FIG. In the first inspection step, inspection is performed by irradiating a plurality of imaging elements 4 fixed to the base 2 with visible light and reading signals from the probe 23. In this step, when a defect is found in a certain image sensor 4, the first heat-peelable adhesive member 3 is heated to replace the image sensor having the defect. An “imaging image sensor having a defect” includes an image sensor whose operation or acquired image is out of an allowable range due to static electricity or foreign matter being involved during mounting or other reasons.

  Next, a second fixing step shown in FIG. The second heat-peelable adhesive member 5 is disposed on the scintillator 6. The second heat-peelable adhesive member 5 is disposed on the scintillator 6 by separating the separators 51 and 52 from the state shown in FIG. A scintillator 6 is fixed to a plurality of image pickup devices 4 fixed to the base 2 via the second heat-peelable adhesive member 5. Here, the second heat-peelable adhesive member 5 is disposed on the scintillator 6 side, but may be disposed on the plurality of image pickup device 4 sides. In particular, in a form using a plurality of image pickup devices, when the second heat-peelable adhesive member 5 is divided and arranged on the image pickup device 4 side corresponding to each of the image pickup devices 4, each of the plurality of image pickup devices 4 is used. On the other hand, it is possible to perform the separation separately, which is more preferable. In addition, since the 1st heat peelable adhesive member 3 and the 2nd heat peelable adhesive member 5 use the same material, the expansion start temperature of the 2nd heat peelable adhesive member 5 is 1st. This is the same as the expansion start temperature of the heat-peelable adhesive member 3.

  Next, a second inspection process shown in FIG. In the second inspection step, the base 2, the plurality of image sensors 4, and the scintillator 6 are fixed, and the scintillator 6 is irradiated with radiation and a signal is read from the probe 23 for inspection. At this time, it is confirmed whether or not the imaging element 4 has a defect. If it is determined that the imaging element 4 has a defect, the base 2 and the imaging element 4 are peeled to replace the imaging element 4. Further, the scintillator 6 is also inspected. If it is determined that there is an influence on the image quality due to the defect of the scintillator 6, the image sensor 4 and the scintillator 6 are peeled to replace the scintillator 6. The peeling process for peeling between the base 2 and the scintillator 6 and the image sensor 4 will be described later with reference to FIGS.

  When defects in the image sensor 4 and the scintillator 6 are not confirmed in the second inspection process, a sealing process shown in FIG. In this sealing step, at least the periphery of the plurality of imaging elements 4 is sealed with the sealing member 11. Since the wiring substrate 10 is fixed by the sealing member 11 in this sealing step, the wiring substrate 10 is in a state of penetrating the sealing member 11. By sealing with the resin 11, the base 2 and the scintillator 6 have a structure that does not easily separate from the plurality of imaging elements 4, and the strength of the radiation imaging apparatus 1 is improved. Further, it is possible to reduce the intrusion of moisture and impurities into the scintillator 6 and the imaging element 4 and each interface from the outside, and the reliability of the radiation imaging apparatus 1 is improved.

  Next, a process of peeling the plurality of image pickup devices 4 from the base 2 will be described with reference to FIG. Here, a case where an image sensor having a defect is included in the plurality of image sensors 4 will be described. First, as shown to Fig.4 (a), a radiation imaging device is thrown into a thermostat and heated. In the thermostat, the same force is applied to the scintillator 6 and the base 2 in a direction perpendicular to the image sensor 4 and away from the image sensor. The heat is transferred to the first heat-peelable adhesive member 3 through the base 2 and starts to expand at the expansion start temperature S in FIG. 2D, and the adhesive force of the first heat-peelable adhesive member 3 is reduced. Start. Furthermore, heat is applied to the first heat-peelable adhesive 3 to reach the maximum expansion temperature M at which the adhesive strength of the first heat-peelable adhesive member 3 is most reduced, and as shown in FIG. One heat-peelable adhesive member 3 becomes the heat-peelable adhesive member 30 having a reduced adhesive force. Due to the force applied to the base 2, the adhesive force of the first heat-peelable adhesive member 3 is lowered at a temperature higher than the expansion start temperature S, and the base 2 and the plurality of imaging elements 4 are peeled off. Here, the heat is transferred to the second heat-peelable adhesive member 5 through the scintillator 6, but the heat transfer amount per unit time of the scintillator 6 is smaller than the heat transfer amount per unit time of the base 2. Therefore, when the first heat peelable adhesive member 3 reaches the expansion start temperature S or the maximum expansion temperature M, the second heat peelable adhesive member 5 still reaches the expansion start temperature S or the maximum expansion temperature M. Absent. Therefore, the second heat-peelable adhesive member 5 does not have a lower adhesive force than the first heat-peelable adhesive member 3, and the scintillator 6 and the image sensor 4 are not peeled off.

  Next, a process of peeling the plurality of image pickup devices 4 from the scintillator 6 will be described with reference to FIG. In this peeling process, first, as shown in FIG. 5A, the plurality of imaging elements 4 are each fixed by the conveying means 21 and heated from the scintillator 6 side. Here, infrared rays are emitted from the scintillator 6 side. The heat is transferred to the second heat-peelable adhesive member 5 through the scintillator 6 and starts to expand at the expansion start temperature S in FIG. Furthermore, heat is applied to the second heat-peelable adhesive 5, and the second heat-peelable adhesive member 5 reaches the maximum expansion temperature M at which the adhesive strength is the lowest. At this time, as shown in FIG. 5B, the second heat-peelable adhesive member 5 becomes a heat-peelable adhesive member 50 having a reduced adhesive force. Here, the force applied to the scintillator 6 reduces the adhesive force of the second heat-peelable adhesive member 5 at a temperature higher than the expansion start temperature S, and the scintillator 6 and the image sensor 4 are peeled off. In the above description, the process of irradiating infrared rays and heating and peeling from the scintillator 6 side is described, but the present invention is not limited thereto. The scintillator 6 and the image sensor 4 may be peeled off by continuing the heating in the previously used thermostatic chamber.

  As described above, according to the present invention, in the radiation imaging apparatus in which the imaging device 4 is sandwiched between the scintillator 6 and the base 2, the imaging device 4 or the scintillator 6 is peeled off while the imaging device 4 is mechanically stable. It becomes possible. In addition, when a heat-peelable adhesive member in which heat-expandable particles are blended in an adhesive is used, the surface of the base from which the image sensor 4 is removed has little adhesive residue, so a new image sensor Can be easily fixed to the base.

(Second Embodiment)
Next, a radiation imaging apparatus according to the second embodiment will be described with reference to FIG. In addition, the same number is provided to the same requirement as 1st Embodiment, and detailed description is abbreviate | omitted about the same requirement and the same process. FIG. 6A is a plan view of main components of the radiation imaging apparatus according to the second embodiment, and FIG. 6B is a cross-sectional view taken along the line AA ′ in FIG. FIG. 6C is a cross-sectional view in which a part of the cross section corresponding to the position AA ′ in FIG. 6A of the entire radiation imaging apparatus is enlarged.

  The difference from the first embodiment in the present embodiment is that a resin layer 16 for controlling the amount of heat transfer is provided between the first heat-peelable adhesive member 3 and the base 2. This can be considered that the surface of the base 2 is a resin layer 16 for controlling the amount of heat transfer, that is, the base 2 and the resin layer 16 can be regarded as a base. . Here, the resin layer 16 uses a paint that absorbs heat or a sheet-like material that absorbs heat. As a material for the heat absorbing paint, a material having a high thermal conductivity is preferable, and it is preferable that a material having a thermal conductivity of 15 (W / (m · K)) or more such as a carbon nanotube or a metal is included. This material having high thermal conductivity is dispersed in a polymer such as an acrylic resin, an epoxy resin, or a silicone resin, applied to the surface on the base 2 side of the image pickup element 4 by screen printing or the like, and dried. As a sheet-like material that absorbs heat, a highly functional silicone gel sheet or a highly thermally conductive silicone rubber sheet can be used. In this case, it is preferable that the sheet material that absorbs heat has an adhesive function on the surface on the imaging element 4 side. Further, the resin layer 16 may be made of a heat insulating paint or a heat insulating sheet-like material. As a heat insulating material, a material having a low thermal conductivity is preferable, and materials having a thermal conductivity of 0.2 (W / (m · K)) or less, such as polymer acrylic resin, epoxy resin, and silicone resin, are preferable. . As a material of the sheet to be thermally insulated, a material having a thermal conductivity of 0.2 (W / (m · K)) or less, such as a polyolefin resin sheet, an acrylic sheet, a rubber sheet, or nylon can be used. In this case, it is preferable that the sheet material to be thermally insulated has an adhesive function on the side surface of the image sensor 4.

  Thereby, since the difference in the amount of heat transfer per unit time between the base 2 and the scintillator 6 can be further increased, the peeling by the first heat peelable adhesive member 3 and the second heat peelability Separation by the adhesive member 5 can be reliably performed separately.

  Further, by controlling the area to be applied and the contact area with the base 2, the amount of heat transfer per unit time of the resin layer 16 is controlled to a desired value. As shown in FIG. 7, the resin layers 16 a and 16 b are divided and provided corresponding to each of the plurality of imaging elements 4. The resin layers 16a and 16b are arranged so that the heat transfer amount is different between the predetermined image pickup device 4 and the base 2 and between the different image pickup devices 4 and the base 2 among the plurality of image pickup devices 4. Place. By doing in this way, it becomes possible to peel the some image pick-up element 4 from the base 2 in desired order, and it becomes possible to peel the some image pick-up element 4 from the base 2 safely and efficiently. In such a case, it is desirable that a plurality of first heat-peelable adhesive members 3 are provided corresponding to the plurality of imaging elements 4 respectively. 7A is a plan view of main components of another example of the radiation imaging apparatus according to the second embodiment, and FIG. 7B is a cross-sectional view taken along the line AA ′ in FIG. 7A. FIG.

(Third embodiment)
An application example of the radiation imaging apparatus according to the present invention to a radiation imaging system will be described with reference to FIG. The X-ray 6060 generated by the X-ray tube (radiation source) 6050 passes through the chest 6062 of the patient or subject 6061 and enters the radiation imaging apparatus 6040 of the present invention including the scintillator 6 and the imaging element 4. This incident X-ray includes information inside the body of the patient 6061. The scintillator 6 emits light in response to the incidence of X-rays, and this is photoelectrically converted to obtain electrical information. This information is converted into a digital signal, image-processed by an image processor 6070 as a signal processing means, and can be observed on a display 6080 as a display means in a control room. The radiation imaging system includes at least a radiation imaging apparatus and a signal processing unit that processes a signal from the radiation imaging apparatus.

  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 a display means such as a doctor room in another place or stored in a recording means such as an optical disk. It is also possible for a 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. It can also be printed on paper by a laser printer as a recording means.

DESCRIPTION OF SYMBOLS 1 Radiation imaging device 2 Base 3 1st heat peelable adhesive member 4 Imaging element 5 2nd heat peelable adhesive member 6 Scintillator 7 Substrate 8 Scintillator layer 9 Protective layer 10 Circuit board 11 Resin 12 Integrated circuit 13 Buffer member 14 Buffer member 15 Case

In order to achieve the above object, the radiation imaging apparatus of the present invention has a base, an imaging element, a scintillator, and a property that an adhesive force is reduced by heating, in order to fix the base and the imaging element. of the first heat peelable adhesive member, has the property of adhesion is reduced by heating, and a second heat peelable adhesive member for fixing said said imaging element scintillator, heat When the conductivity is k (J / s · m · K), the thickness of the member is L (m), and the contact area with the heat transfer member is S (m ² ), the amount of heat transfer per unit time Q is defined by Q = k × S / L, and the heat conduction amount per unit time of the base is different from the heat conduction amount per unit time of the scintillator.

A method of manufacturing a radiation imaging apparatus of the present invention, an imaging device, via a first heat peelable adhesive member having a property of adhesion is reduced to secure a base by heating, the adhesive force is reduced by heating A fixing step of fixing to a scintillator having a heat conductivity per unit time different from that of the base via a second heat-peelable adhesive member having a property of inspecting the imaging element fixed to the base A method of manufacturing a radiation imaging apparatus including an inspection step, wherein the thermal conductivity is k (J / s · m · K), the thickness of the member is L (m), and the contact with the heat transfer member When the area is S (m ² ), the heat transfer amount Q per unit time is defined as Q = k × S / L, and it is determined in the inspection step that the image sensor or the scintillator has a defect by inspection. In the case of By heating the heat peelable adhesive member and heating the second heat peelable adhesive member via the scintillator, one of the base and the scintillator having a large heat transfer amount per unit time and the above It further includes a peeling step in which peeling between the imaging device is performed, and peeling between the other of the base and the scintillator with a small amount of heat transfer per unit time and the imaging device is not performed. Features.

Claims (10)

The base,
An image sensor;
A scintillator,
A first heat-peelable adhesive member for fixing the base and the imaging element, having a property of reducing the adhesive force by heating;
The first heat-peelable adhesive member and the second heat-peelable adhesive member for fixing the imaging element and the scintillator to have the same temperature at which the adhesive force decreases,
A radiation imaging apparatus, wherein a heat transfer amount per unit time of the base is different from a heat transfer amount per unit time of the scintillator.   The first heat-peelable adhesive member and the second heat-peelable adhesive member each include an adhesive and a foaming agent blended in the adhesive.   The amount of heat transfer per unit time of the scintillator is 1/10 or less, or 10 times or more when the heat transfer amount per unit time of the base is 1. The radiation imaging apparatus according to 1 or 2.   The said base has a resin layer for controlling the amount of heat transfer, The said resin layer comprises the surface of the base 2 which contact | connects the said image pick-up element, The any one of Claim 1 to 3 characterized by the above-mentioned. The radiation imaging apparatus according to Item. A plurality of the imaging elements are fixed to the base by the first heat-peelable adhesive member,
The resin layer is divided and provided corresponding to each of the plurality of imaging elements,
Among the plurality of image pickup devices, the predetermined image pickup device and the resin layer corresponding to the predetermined image pickup device among the divided resin layers and the image pickup device different from the predetermined image pickup device are divided. The radiation imaging apparatus according to claim 4, wherein heat transfer amounts differ between resin layers corresponding to the different imaging elements.   The contact area is different between the predetermined image sensor and the resin layer corresponding to the predetermined image sensor, and between the different image sensor and the resin layer corresponding to the different image sensor. The radiation imaging apparatus according to claim 5.   The radiation imaging apparatus according to claim 5 or 6, wherein a plurality of the first heat-peelable adhesive members are provided corresponding to each of the plurality of imaging elements.   The radiation imaging apparatus according to any one of claims 1 to 7, wherein the second heat-peelable adhesive member has a light transmission property that transmits light from the scintillator. The radiation imaging apparatus according to any one of claims 1 to 8,
A radiation imaging system comprising: signal processing means for processing a signal from the radiation imaging apparatus. The imaging element is fixed to the base via a first heat-peelable adhesive member having a property that the adhesive force is reduced by heating, and the temperature at which the adhesive force is reduced is the same as that of the first heat-peelable adhesive member. A fixing step of fixing with a scintillator having a different heat transfer amount per unit time from the base through the heat-peelable adhesive member of 2,
An inspection step of inspecting the imaging device fixed to the base and the scintillator;
A method of manufacturing a radiation imaging apparatus including:
When it is determined in the inspection step that the imaging element has a defect, the first heat-peelable adhesive member is heated through the base and the second heat-peelable through the scintillator. By heating the adhesive member, peeling between the imaging device and one of the base and the scintillator having a large heat transfer amount per unit time is performed, and the unit of the base and the scintillator A method for manufacturing a radiation imaging apparatus, further comprising a peeling step in which peeling between the other one having a small amount of heat transfer per time and the imaging element is not performed.

Images