JP6333034B2 - Manufacturing method of radiation imaging apparatus - Google Patents

Description

The present invention relates to the production how the radiation imaging equipment.

  Conventionally, a radiation imaging apparatus having a narrow frame has been proposed in Patent Documents 1 and 2. Patent Document 1 discloses a radiation imaging apparatus having a configuration that can prevent resolution reduction and scintillator peeling near a joint when a plurality of such devices are used side by side for large-area imaging. Patent Document 2 discloses a method for providing a technique advantageous for improving image quality in mammography.

JP 2002-48870 A JP 2012-107960 A

  In Patent Document 1, when a scintillator is formed on a sensor panel, the sensor panel is supported in the housing portion by supporting the electrode pad portions provided along the two sides by the protruding portion of the substrate holder for vapor deposition. Housed and supported. On the other hand, a notch is formed on the light receiving part side of the substrate holder for vapor deposition on the side close to the light receiving part of the sensor panel, and the top part of the side wall of the sensor panel is arranged to be exposed to the vapor deposition chamber. Is done. When a scintillator is formed on the sensor panel in this state, there is a problem that variations in scintillator characteristics such as luminance and MTF (Modulation Transfer Function) increase. The variation in scintillator characteristics is due to the difference in material between the substrate holder for vapor deposition and the scintillator panel. The reason why the scintillator characteristics vary greatly when the materials for the substrate holder for vapor deposition and the scintillator panel are different is that the heat capacity and the adhesion rate of the scintillator differ depending on the material. Further, when the scintillator is a columnar crystal such as cesium iodide (CsI), there is a problem that the verticality of the columnar scintillator is lowered at the end of the sensor panel.

  In patent document 2, a scintillator is formed in a sensor panel by vapor-depositing while rotating the holding part holding the sensor panel. However, since the sensor panel and the holding portion are made of different materials, there is a problem that the variation in scintillator characteristics becomes large at the end of the sensor panel. The cause of the variation in the scintillator characteristics is that, as in Patent Document 1, the materials of the sensor panel and the holding part are different, and the heat capacity and the scintillator adhesion rate are different.

  An object of this invention is to provide the radiation imaging device which reduced the dispersion | variation in the scintillator characteristic in an edge part.

One embodiment of the present invention, said sensor portion side surface of the sensor panel having a sensor unit for detecting light on the sensor substrate and the sensor substrate and the surface of the second substrate, the scintillator is deposited Forming a scintillator layer; and separating the sensor panel on which the scintillator layer is formed from the second substrate on which the scintillator layer is formed to obtain a radiation imaging apparatus, the scintillator layer comprising: The forming step is performed while holding the sensor substrate so that the side surface of the sensor substrate and the side surface of the second substrate are in contact with each other or are positioned with a gap of twice or less the thickness of the scintillator layer. Features.

  ADVANTAGE OF THE INVENTION According to this invention, the radiation imaging device which reduced the dispersion | variation in the scintillator characteristic in an edge part can be provided.

It is a figure which shows the manufacturing method of the radiation imaging device of 1st Embodiment. It is a figure which shows the manufacturing method of the radiation imaging device of 2nd Embodiment. It is a figure which shows the manufacturing method of the radiation imaging device of 3rd Embodiment. It is a figure which shows the manufacturing method of a radiation imaging device. It is a figure explaining the level | step difference between board | substrates. It is the schematic diagram which hold | maintained the sensor board | substrate by electrostatic adsorption. It is the schematic diagram which hold | maintained the sensor board | substrate with the adhesive sheet. It is a figure which shows a radiation imaging system.

[First Embodiment]
Hereinafter, the manufacturing method of the radiation imaging device of 1st Embodiment of this invention is demonstrated based on FIG. FIG. 1A is a cross-sectional view illustrating a method for manufacturing the radiation imaging apparatus according to the first embodiment. The sensor panel 10 includes a sensor substrate (first substrate) 2 and a sensor unit (pixel unit) 3 that detects light disposed on the sensor substrate 2. As the sensor substrate 2, an insulating substrate such as a glass substrate, a silicon substrate, an aluminum substrate, a carbon substrate such as amorphous carbon, or the like is used.

  A deposition holding unit (holder) 1 for forming the scintillator layer 8 on the surface of the sensor panel 10 on the sensor unit 3 side cooperates with the weight member 4 to hold the sensor panel 10. The holder 1 supports the peripheral part of the vapor deposition surface of the two sensor panels 10. On the other hand, the weight member 4 presses the peripheral edge portion on the back surface on the side opposite to the vapor deposition surface side of the sensor panel 10.

  The holder 1 is mainly made of metal. As the material of the support part 1, stainless steel, particularly SUS304, SUS316 is used. The weight member 4 corrects the deflection due to the weight of the sensor panel 10 by pressing a part of the peripheral edge on the back surface opposite to the vapor deposition surface of the sensor panel 10. The material of the weight member 4 may be any member that can correct bending such as metal, for example, stainless steel such as SUS304 and SUS316, or resin such as fluorine resin, polyimide resin, silicon resin, and polyetheretherketone. A stacked structure may be used. In particular, as the weight member 4, it is possible to use a resin that reduces the thermal effect during vapor deposition on the sensor panel 10. In particular, as the weight member 4, a heat-resistant resin such as polyimide resin, silicon resin, or polyether ether ketone can be used.

  In the first embodiment, the side surfaces of the sensor substrates 2 of the plurality of sensor panels 10 are abutted against each other, and the deposition surfaces on the sensor unit side of the plurality of sensor panels 10 are held in a continuous and flush state. In the peripheral part on the side of the abutting part 5 where the side surfaces of the sensor substrate 2 are abutted, the radiation imaging apparatus forms a narrow frame part.

Here, the abutting portion 5 refers to a member that satisfies the following two conditions.
(1) A scintillator that forms gaps between the side surfaces even if the side surfaces of the plurality of sensor substrates 2 are at least partially in contact with each other, or even if the side surfaces of the plurality of sensor substrates 2 are spaced from each other. The thickness of the layer 8 is twice or less, preferably 0.1 mm or less.
(2) The steps on the surface on the vapor deposition surface side of the plurality of sensor panels 10 are smaller than the thickness of the scintillator layer 8.

  For the formation of the scintillator layer 8, a vacuum deposition method or the like is used. A scintillator layer 8 is formed on the deposition surface on the sensor portion side of the sensor substrate 2 by placing the scintillator material in a crucible (container) (not shown) installed in the lower part of FIG. Is done. As the scintillator, cesium iodide (CsI), sodium iodide (NaI) or the like is used, and as the dopant (activator), Tl (thallium), Na (sodium), or the like is used to form columnar scintillator particles. The FIG. 1B is a plan view illustrating the method for manufacturing the radiation imaging apparatus according to the first embodiment. Two sensor substrates 2 are abutted, and weight members 4 are respectively installed at four corners of each sensor substrate 2.

  Two radiation imaging devices are obtained by separating the two sensor substrates 2 on which the scintillator layers are formed. In the first embodiment, the case where the same two sensor substrates 2 are abutted is shown. However, of the two substrates to be abutted, one is the sensor substrate 2 and the other one has the same heat capacity or scintillator adhesion probability as the sensor substrate 2, or is formed of the same material as the sensor substrate 2. The second substrate may be used. When the same two sensor substrates 2 are brought into contact with each other, two radiation imaging devices having a very narrow frame can be manufactured at the same time, and thus the manufacturing cost can be reduced.

  In the present embodiment, the first substrate is the sensor substrate 2 constituting the sensor panel 10 used when the scintillator layer 8 is directly formed on the sensor panel 10. However, the first substrate is a substrate (indirect substrate) that forms the scintillator panel by depositing the scintillator when the scintillator panel is attached to the sensor panel 10 after the scintillator layer 8 is formed and the scintillator panel is obtained. May be. As the indirect substrate, a silicon substrate, an aluminum substrate, a carbon substrate such as amorphous carbon, or the like is used.

  The combinations of the first substrate and the second substrate are shown in Table 1 below.

  When a plurality of sensor substrates 2 are abutted, a step may be generated between the plurality of sensor substrates 2. The step (surface step) between the plurality of sensor substrates 2 is preferably small. As shown in FIG. 5 (b), when the steps of the vapor deposition surfaces of the plurality of sensor substrates 2 exceed the thickness of the scintillator layer 8, the scintillator adheres to the side surface of the sensor substrate 2, and the end of the scintillator layer 8. The columnar crystal of the scintillator grows inclined at the part. On the other hand, as shown in FIG. 5A, when the step of the deposition surface of the sensor substrate 2 is equal to or less than the thickness of the scintillator layer 8, the columnar crystals of the scintillator grow vertically at the end of the scintillator layer 8. Therefore, the scintillator layer 8 has a side wall perpendicular to the vapor deposition surface, has a uniform thickness, and can reduce variations in scintillator characteristics such as luminance and MTF.

[Second Embodiment]
Hereinafter, the manufacturing method of the radiation imaging apparatus of 2nd Embodiment is demonstrated based on FIG. 2A is a cross-sectional view of the second embodiment, and FIG. 2B is a plan view. Also in the second embodiment, as in the first embodiment, the scintillator layer 8 is formed while being held using the holder 1 and the weight member 4 while the two sensor substrates 2 are abutted by the abutting portion 5. .

  The second embodiment is different from the first embodiment in that a connection member 6 for connecting the two sensor substrates 2 is installed between the two sensor substrates 2. As the connection member 6, a material different from that of the sensor substrate 2 having the same heat capacity as that of the sensor substrate 2 and the adhesion probability of the scintillator is used. The connecting member 6 is made of the same material as that of the sensor substrate 2. The connecting member 6 has a role of uniformly defining the size of the gap between the two sensor substrates 2 in the connecting portion, and the size of the gap is 0.1 mm or less. As described with reference to FIG. 5, when the distance between the two sensor substrates 2 exceeds 0.1 mm, it is difficult to reduce variation in scintillator characteristics. When the size of the gap is 0.1 mm or less, the columnar crystal of cesium iodide can be formed vertically even in the connecting portions connected to each other, and variations in scintillator characteristics can be reduced.

[Third Embodiment]
Hereinafter, the manufacturing method of the radiation imaging device of 3rd Embodiment is demonstrated based on FIG. FIG. 3 is a cross-sectional view of the third embodiment. Also in the third embodiment, as in the first embodiment, the scintillator layer 8 is formed while being held using the holder 1 and the weight member 4 in a state where the two sensor substrates 2 are abutted by the abutting portion 5. .

  In the third embodiment, in a state where the two sensor substrates 2 are abutted, a part of the side surfaces of the two sensor substrates 2 on the vapor deposition surface side contact each other, and the remaining part on the back side of the side surfaces is a tapered space. Form. The member 7 having a shape corresponding to the tapered shape is disposed in the tapered space. With such a configuration, the contact area between the side surfaces of the two sensor substrates 2 in the abutting portion 5 increases. As a result, variation in scintillator characteristics at the abutting portion 5 can be further reduced.

  Hereinafter, a method for obtaining the plurality of sensor panels 10a and 10b used in the first to third embodiments will be described with reference to FIG. As the sensor panel 10, the case where the sensor substrate 2 in which the TFT portion and the sensor portion 3 are formed on the glass substrate (holding substrate) 100 is used is shown. A plurality of sensor substrates 2 are arranged on a large-area glass substrate 100. In the case of this embodiment, two sensor panels 10a and 10b are arranged. The glass substrate 100 is cut out to obtain the sensor panel 10a and the sensor panel 10b. After the cutting, the two sensor panels 10a and 10b are placed in the vapor deposition holder 1 with the cut surface as the butting portion 5.

  As a method for cutting out the glass substrate 100, there are methods such as slicer, diamond saw, dicing, and laser cutting. Since the cut portions are brought into contact with each other, cutting with a laser that has less unevenness on the cut surface and increases the contact area is more preferable. In the mass production process, since a plurality of glass substrates 100 move, there are cases where sensor panels cut out from different glass substrates 100 are abutted with each other and sensor panels cut out from the same glass substrate 100 are abutted. .

  Even if there are irregularities on the cut surface, the contact area is larger when the sensor panels cut out from the same glass substrate 100 are abutted with each other than when the sensor panels are cut out from different glass substrates. Can be further reduced.

[Other Embodiments]
In the present embodiment, as a method of holding the two sensor substrates 2, the case where the two sensor substrates 2 are abutted and held is illustrated. However, a method of holding the two sensor substrates 2 on the base 12 by electrostatic adsorption, or holding the two sensor substrates 2 on the base 12 via a heat-resistant adhesive sheet (adhesive layer) 15. Also good.

  FIG. 6 shows a case where two sensor substrates 2 are held by electrostatic adsorption (electrostatic chuck). The electrostatic chuck 9 is provided with a dielectric layer or an insulating layer 11 on a base 12, applies a voltage between the base 12 and the sensor substrate 2, and attracts the sensor substrate 2 by a force generated between the two. . It is classified into Coulomb force type and Johnson Rabeck force type according to the difference in adsorption method. The Coulomb force type uses an insulating material as a dielectric. On the other hand, the Johnson-Rabeck force type, which exhibits a strong adsorption force at a low voltage, is often used for ceramic electrostatic chucks such as alumina, and is excellent in terms of heat resistance and plasma resistance.

  Since the electrostatic chuck 9 does not use a mechanical holder, the entire surface of the sensor substrate 2 can be uniformly deposited. For this reason, the sensor substrate 2 is widely spread as a device for adsorption fixation, and it is possible to control the substrate temperature during vapor deposition by heating the substrate in combination with a heater.

  Before voltage application, the surface of the sensor substrate 2 is in a stable state. When a voltage is applied to the electrode pattern, a strong electric field is formed on the surface (adsorption surface) of the sensor substrate 2 and the surface of the sensor substrate 2 is polarized. Therefore, a potential difference is generated between the electrostatic chuck 9 and the sensor substrate 2, and a Coulomb force 13 that attracts each other is induced to attract the sensor substrate 2. A scintillator (CsI: Tl) is vapor-deposited while rotating the base 12 with the rotating shaft 16 in the adsorbed state.

  On the contrary, when the voltage applied to the electrostatic chuck 9 is cut off at the time of release (release of adsorption), the electric field from the electrode pattern that restrains the surface polarization of the sensor substrate 2 disappears. For this reason, the surface polarization of the sensor substrate 2 is also instantaneously lost, and there is no potential difference between the electrostatic chuck 9 and the surface of the sensor substrate 2, and the electrostatic attraction force 13 disappears. That is, the sensor substrate 2 can be released (adsorption released) by simply cutting off the applied voltage.

  FIG. 7 is a schematic view when two sensor substrates 2 are held by the heat-resistant adhesive sheet 15. The base 12 and the sensor substrate 2 are held on the base 12 via the adhesive sheet 15. A scintillator (CsI: Tl) is vapor-deposited while rotating the base 12 with the rotating shaft 16 in a state where the plurality of sensor substrates 2 are held by the adhesive sheet 15. As the adhesive sheet 15, a silicon-based, acrylic-based, acrylic-silicon-based sheet, or the like is used.

[Radiation imaging system]
A radiation imaging system including the radiation imaging apparatus 200 manufactured in each of the above embodiments will be described with reference to FIG. As shown in FIG. 8, the radiation (X-rays) 211 generated by the X-ray tube (radiation source) 210 passes through the chest 221 of the patient or subject 220 and enters the radiation imaging apparatus 200. This incident X-ray includes information inside the body of the patient 220. The scintillator layer 8 emits light corresponding to the incidence of X-rays, and this light emission is photoelectrically converted by the sensor unit (photoelectric conversion element) 3 of the sensor panel 10 to obtain electrical information. This electrical information is converted into digital data, subjected to image processing by a signal processing unit (image processor) 230, and can be observed by a display unit (display) 240.

  Information processed by the image processor 230 can be transferred to a remote location by a transmission processing unit 250 such as a network such as a telephone, a LAN, and the Internet. Therefore, the information processed by the image processor 230 can be displayed on a display unit (display) 241 such as a doctor room in another place, or can be stored in a recording unit such as an optical disk. Can be diagnosed by Information processed by the image processor 230 can also be recorded on the film 261 by the film processor 260.

  The radiation imaging apparatus 200 of the present invention can be applied to a medical radiation imaging apparatus or a non-medical analysis or inspection apparatus using radiation, such as a nondestructive inspection apparatus.

  1: Holder. 2: Sensor substrate. 3: Sensor part. 4: Weight member. 5: Butting part. 6: Distance adjusting member. 7: Attaching member. 8: Scintillator layer. 10: Sensor panel.

Claims (17)

Forming a scintillator layer by vapor-depositing a scintillator on a surface of the sensor substrate having a sensor substrate and a sensor panel that detects light on the sensor substrate, and a surface of the second substrate;
Separating the sensor panel on which the scintillator layer is formed from the second substrate on which the scintillator layer is formed to obtain a radiation imaging apparatus;
Including
In the step of forming the scintillator layer, the side surface of the sensor substrate and the side surface of the second substrate are in contact with each other or are held so as to be positioned with a gap less than twice the thickness of the scintillator layer. The manufacturing method of the radiation imaging device characterized by performing.   In the step of forming the scintillator layer, the sensor panel and the second substrate are formed such that a step between the surface of the sensor panel and the surface of the second substrate is smaller than a thickness of the scintillator layer. The manufacturing method according to claim 1, wherein the holding method is held.   In the step of forming the scintillator layer, the sensor panel and the second substrate are in contact with each other so that the side surface of the sensor substrate and the side surface of the second substrate are in contact with each other. The manufacturing method according to claim 1, wherein the second substrate is held.   In a state where the sensor substrate and the second substrate are abutted, a part of the side of the side surface of the sensor substrate is in contact with a part of the side surface of the second substrate, and In the state opposite to the surface, the remaining part of the side surface of the sensor substrate and the remaining part of the side surface of the second substrate form a tapered space, and the tapered member is disposed in the space. The manufacturing method according to claim 3, wherein the panel and the second substrate are held.   In the step of forming the scintillator layer, the side surface of the sensor substrate and the side surface of the second substrate are arranged with a gap of 0.1 mm or less, defining the size of the gap, and the sensor substrate 3. The manufacturing method according to claim 1, wherein the sensor panel and the second substrate are held in a state in which a connection member that connects the second substrate is disposed in the gap. 4. Wherein in the step of forming a scintillator layer, we claim 1, characterized in that for supporting the peripheral portion of the front Symbol table surface of the second substrate and the peripheral portion of the sensor portion side surface of the sensor panel 5 The manufacturing method of any one of these.   In the step of forming the scintillator layer, pressing a part of the peripheral part on the back surface on the side opposite to the surface of the sensor panel and a part of the peripheral part on the surface on the back surface side of the second substrate. The manufacturing method of Claim 6 characterized by the above-mentioned.   In the step of forming the scintillator layer, the back surface of the sensor panel opposite to the surface and the back surface of the second substrate are held on a base by an electrostatic chuck. Item 4. The method according to any one of Items 1 to 3.   The step of forming the scintillator layer, wherein a back surface opposite to the surface of the sensor panel and a surface of the second substrate on the back surface side are held on a base by an adhesive layer. 4. The production method according to any one of 1 to 3.   10. The manufacturing method according to claim 1, wherein the second substrate is a sensor substrate and another sensor panel including a sensor unit that detects light on the sensor substrate. .   The manufacturing method according to claim 10, wherein the sensor panel and the other sensor panel are formed on the same holding substrate, and are obtained by cutting out the holding substrate.   The manufacturing method according to claim 1, wherein the second substrate is formed of the same material as the sensor substrate.   The manufacturing method according to claim 1, wherein the second substrate has at least one of a scintillator adhesion probability and a heat capacity equal to that of the sensor substrate. The deposition surface of the first substrate while holding the first substrate and the second substrate so that the side surface of the first substrate and the side surface of the second substrate are in contact with each other or are positioned with a gap therebetween. And forming a scintillator layer by vapor-depositing a scintillator on the vapor deposition surface of the second substrate;
Separating the first substrate on which the scintillator layer is formed from the second substrate on which the scintillator layer is formed, and obtaining a scintillator panel;
Attaching the scintillator panel to the sensor unit side of the sensor panel having a sensor substrate and a sensor unit for detecting light on the sensor substrate to obtain a radiation imaging apparatus;
Including
The method of manufacturing a radiation imaging apparatus, wherein the gap is not more than twice the thickness of the scintillator layer.   In the step of forming the scintillator layer, the step of forming the first substrate and the second substrate so that a step between the vapor deposition surface of the first substrate and the vapor deposition surface of the second substrate is smaller than the thickness of the scintillator layer. The manufacturing method according to claim 14, wherein the second substrate is held.   16. The manufacturing method according to claim 14, wherein the first substrate and the second substrate are made of the same material.   16. The manufacturing method according to claim 14, wherein the second substrate has at least one of a scintillator adhesion probability and a heat capacity equal to that of the first substrate.

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