JP2006343277A - Radiation detection device and radiation imaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation detection device and a radiation imaging system capable of improving durability without using a sealing resin. <P>SOLUTION: At least a part in contact with a part of the surface of a sensor panel 100 of a phosphor protection layer 113 is an ultraviolet bridging type adhesive member, for example, at least a part in direct contact with the sensor panel 100 of the phosphor protection layer 113 is an ultraviolet bridging type adhesive sheet, or the whole phosphor protection layer 113 is the ultraviolet bridging type adhesive sheet, to thereby form a part having an equivalent function to the sealing resin by curing it by ultraviolet irradiation. Since the ultraviolet bridging type adhesive member has high shape tracking of the sheet on the upper part of the phosphor layer, durability and mechanical strength of the phosphor layer can be improved. In addition, since a sealing process by liquid resin can be abolished, process simplification or cost reduction can be realized. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radiation detection apparatus used for medical diagnostic equipment, non-destructive inspection equipment, and the like, and a radiation imaging system using the same.

  Conventionally, an X-ray film system having a fluorescent screen having an X-ray phosphor layer and a double-side coating agent is generally used for X-ray photography. On the other hand, recently, the digital radiation detection apparatus having an X-ray phosphor layer and a two-dimensional photodetector has good image characteristics, and the data is digital data. Since there is an advantage of sharing, active research and development have been conducted on digital radiation detection devices, and various patent applications have been filed.

  Among these digital radiation detection devices, as disclosed in Patent Documents 1 and 2 as high-sensitivity and sharp devices, electrical elements such as a plurality of photosensors and TFTs (Thin Film Transistors) are provided on a substrate. A phosphor layer (scintillator layer) for converting radiation into light that can be detected by the photoelectric conversion element on a photodetector (also referred to as a “sensor panel”) having a photoelectric conversion element portion arranged two-dimensionally A radiation detection apparatus (also referred to as “bonding type” or “indirect type”) configured by bonding a scintillator panel formed of a formed support plate is known.

  In addition, as disclosed in Patent Document 3, radiation is applied to a photoelectric conversion element on a photodetector (sensor panel) including a photoelectric conversion element unit in which a plurality of electric elements such as photosensors and TFTs are two-dimensionally arranged. There is known a radiation detection apparatus (also referred to as “direct vapor deposition type” or “direct type”) in which a phosphor layer (scintillator layer) for converting into light that can be detected by the above is directly formed.

  FIG. 8 shows a cross-sectional view of a conventional radiation detection apparatus. In the figure, 101 is a glass substrate, 102 is a wiring portion, 103 is a photoelectric conversion element portion comprising a photosensor and TFT using amorphous silicon, 104 is an electrode extraction portion (electrode pad portion), and 105 is an inorganic film such as silicon nitride. A first protective film (passivation film) 106 and a second protective film (planarization layer) made of an organic film such as polyimide are shown (the second protective film is formed as necessary).

  The sensor panel 100 is configured by these components. A phosphor layer (scintillator layer) 112 is formed on the sensor panel 100 so as to correspond to the photoelectric conversion element portion 103. Further, a phosphor protective layer 113 is formed so as to cover the upper surface and side surfaces of the scintillator layer 112 and to be in contact with the surface of the sensor panel 100 (second protective film 106 in FIG. 8).

On the phosphor protective layer 113, a moisture-proof protective layer 114 that also serves as a reflective layer that reflects light emitted from the phosphor layer 112 toward the photoelectric conversion element portion 103 is provided. A sealing resin 204 is provided on the end surfaces of the sensor panel 100, the phosphor protective layer 113, and the moisture-proof protective layer 114. Conventionally, as a sealing resin, a liquid type ultraviolet curable resin is generally used in order to satisfy durability.
Japanese Patent Laid-Open No. 10-341013 Japanese Patent No. 3405706 JP-A-5-180945

  The conventional phosphor protective layer needs to improve durability by forming a sealing resin at the end. Conventionally used UV curable resin is a liquid application type, and if there is an uncured part, the liquid will not crosslink and remain as it is, and it may penetrate between the sensor panel and the phosphor and cause image defects. there were. Furthermore, the process for forming the phosphor protective layer, the moisture-proof layer, and the sealing layer is not only complicated, but there are problems such as the occurrence of protrusions and uncured portions due to the use of the liquid resin.

  The objective of this invention is providing the radiation detection apparatus and radiation imaging system which can improve durability, without using sealing resin.

  The radiation detection apparatus of the present invention includes a sensor panel having at least a photoelectric conversion unit having a plurality of photoelectric conversion elements arranged one-dimensionally or two-dimensionally on a substrate, and the sensor panel corresponding to the photoelectric conversion unit. And a phosphor layer having a phosphor that converts radiation into light that can be sensed by the photoelectric conversion element, and a phosphor protective layer that covers at least the surface and side surfaces of the phosphor layer and a partial surface of the sensor panel And at least a portion of the phosphor protective layer that is in contact with a part of the surface of the sensor panel is made of an ultraviolet crosslinking adhesive member.

  The radiation imaging system of the present invention includes the radiation detection apparatus, a signal processing means for processing a signal from the radiation detection apparatus, a recording means for recording a signal from the signal processing means, and the signal processing. It comprises a display means for displaying a signal from the means, a transmission processing means for transmitting a signal from the signal processing means, and a radiation source for generating the radiation.

  In the present invention, at least a portion of the phosphor protective layer that is in contact with a part of the surface of the sensor panel is an ultraviolet-crosslinking adhesive member. The ultraviolet-crosslinking adhesive member can be cured with ultraviolet rays, and is made of a sheet-like adhesive resin film before curing. In addition, the ultraviolet cross-linking adhesive member has high sheet conformability at the upper part of the phosphor layer, and can improve the durability and mechanical strength of the phosphor layer. Furthermore, since the sealing step using a liquid resin can be eliminated, the process can be simplified or reduced in cost.

  According to the present invention, by providing at least a portion of the phosphor protective layer that is in contact with a part of the surface of the sensor panel as an ultraviolet-crosslinking adhesive member, a highly durable radiation detection apparatus is provided without forming a sealing resin. It becomes possible. Further, the functions of the phosphor moisture-proof layer serving as the phosphor protective layer and the reflective layer and the sealing resin can be simultaneously formed at the same time, and the manufacturing process can be simplified.

  Furthermore, since it is not necessary to provide a sealing layer made of a liquid UV curable resin in order to improve the moisture resistance of the phosphor, no defect occurs in the image due to the remaining liquid resin uncured portion. In addition, a sensor panel can be manufactured at low cost, and a highly durable radiation detection apparatus can be obtained.

  In addition, since the UV-crosslinking type adhesive member is formed to follow the shape by pressurization, the phosphor protective layer has a high hermeticity and is provided to follow the shape by deforming the uneven shape on the top of the phosphor layer. Further, the durability and rigidity of the phosphor layer can be improved.

  Next, the best mode for carrying out the invention will be described in detail with reference to the drawings. In the specification of the present application, it is assumed that the category of radiation includes X-rays, α rays, β rays, γ rays, and the like.

(First embodiment)
FIG. 1 is a sectional view showing a first embodiment of a radiation detection apparatus according to the present invention. In FIG. 1, the same parts as those in the conventional apparatus of FIG. In the figure, 101 is a glass substrate, 103 is two-dimensionally formed on the glass substrate 101, a photoelectric conversion element portion corresponding to a pixel composed of a photosensor and TFT using amorphous silicon, and 102 is formed on the glass substrate 101. A wiring portion connected to the photoelectric conversion element portion 103; 104, an electrode extraction portion (electrode pad portion) connected to the wiring portion 102; 105, silicon nitride covering the photoelectric conversion element portion 103 and the wiring portion 102; It is a protective layer (first protective film).

  A sensor panel (also referred to as “two-dimensional photodetector”, “photoelectric conversion panel”, or the like) 100 is configured by these components 101 to 105. Further, a second protective film 106 made of an organic resin layer may be provided on the protective film 105 as necessary. Further, a phosphor layer 112 is formed on the first protective film 105 or the second protective film 106. The phosphor layer 112 is made of a phosphor having a columnar crystal structure made of alkali halide such as CsI: Na and CsI: Tl formed on the sensor panel by vapor deposition.

  The surface of the protective film 106 on which the phosphor layer 112 is formed is preferably subjected to a so-called surface treatment in order to improve adhesion with the phosphor layer. As the surface treatment method, a generally known treatment method can be used, and examples thereof include surface modification such as corona treatment, plasma treatment, and UV irradiation treatment.

  On the phosphor layer 112, a moisture-proof protective layer 114 made of a metal serving as a phosphor protective layer 113 and a reflective layer is formed. The phosphor protective layer 113 is press-formed so as to cover the phosphor layer 112 from the upper surface to the side surface, and at least an end is directly formed on the surface of the sensor panel 100 so that the phosphor layer 112 is shielded from the outside. ing.

  The moisture-proof protective layer 114 is preferably made of a material that reflects light from the phosphor layer 112 and prevents moisture from entering from the outside, and particularly a metal material. Specifically, metals having high reflectivity such as Al, Ag, Cr, Cu, Ni, Ti, Mg, Rh, Pt, and Au are desirable. Further, a resin layer (not shown) is desirably laminated on the moisture-proof protective layer 114 for the purpose of protecting the rigidity. The phosphor protective layer 113 and the moisture-proof protective layer 114 are formed simultaneously.

  Further, in the above-described radiation detection apparatus, the electrode extraction portion 104 of the sensor panel 100 has an anisotropic conductive adhesive having a terminal portion of a flexible circuit board (not shown) on which a driving or detection integrated circuit IC is mounted. (Not shown).

  The phosphor protective layer 113 is made of an ultraviolet crosslinking adhesive sheet. A phosphor layer 112, a phosphor protective layer 113, and a moisture proof protective layer 114 are disposed on the sensor panel 100, and the adhesive sheet resin is cross-linked in the end region irradiated with the ultraviolet rays by irradiating the ultraviolet rays from the back surface of the sensor panel 100. The reaction proceeds, and it becomes possible to form a portion having the same effect as the sealing resin.

  The phosphor protective layer 113 is a material that covers the phosphor layer 112 and is provided for the purpose of moisture-proof protection of the phosphor layer 112, and is a sheet-like material that waits for adhesiveness and undergoes a crosslinking reaction by ultraviolet irradiation. Any material may be used. In particular, a resin material having high moisture resistance, high transmittance in the phosphor emission wavelength region, and easy to form in a thin layer is desirable.

  The material of the phosphor protective layer 113 is a material in which an ultraviolet curable resin component, a photopolymerization initiator and an adhesive component are mixed, for example, a rubber-based, silicone-based, acrylic-based adhesive material, Specifically, materials such as those disclosed in JP-A-2002-348543 can be suitably used. Moreover, since an ultraviolet-crosslinking type adhesive sheet has adhesiveness before hardening, it can form an adhesive sheet on a release film and can be transcribe | transferred to another to-be-adhered body according to use.

As the first protective film 105 or the second protective film 106 that is a protective layer of the sensor panel used in the present embodiment, in addition to SiN, TiO ₂ , LiF, Al ₂ O ₃ , MgO, etc., polyphenylene sulfide resin, Fluorine resin, polyether ether ketone resin, liquid crystal polymer, polyether nitrile resin, polysulfone resin, polyether sulfone resin, polyarylate resin, polyamideimide resin, polyetherimide resin, polyimide resin, epoxy resin, acrylic resin, silicon resin Etc. are preferably used.

  Since light converted by the phosphor layer 112 passes through the first protective film 105 and the second protective film 106 when irradiated with radiation, the first protective film 105 and the second protective film 106 exhibit high transmittance at the wavelength of light emitted from the phosphor layer 112. Things are desirable. In particular, the second protective layer 106 disposed in the portion where the phosphor protective layer 113 is in direct contact with the sensor panel 100 is efficiently irradiated from the back surface of the sensor panel 100 when the UV-crosslinked adhesive sheet is cured. In order to perform well, a material / configuration having a high transmittance in the wavelength region necessary for the crosslinking reaction is preferable.

  As the phosphor layer 112, an alkali halide having a columnar crystal structure: an activator is preferably used. In addition to CsI: Tl, CsI: Na, NaI: Tl, LiI: Eu, KI: Tl, or the like is used. Can do.

(Second Embodiment)
FIG. 2 is a cross-sectional view showing a second embodiment of the present invention. In FIG. 2, the same parts as those of FIG. In the present embodiment, as the phosphor protective layer 113, an adhesive material 115 is used for a portion in contact with the phosphor layer 112, and an ultraviolet cross-linked adhesive sheet 116 is used for a portion in contact with the sensor panel 100. Other configurations are the same as those in FIG.

  In the present embodiment, as in the first embodiment, the crosslinking reaction of the adhesive sheet resin proceeds in the end region of the sensor panel 100 by irradiating ultraviolet rays from the back surface of the sensor panel 100, and the same effect as the sealing resin is obtained. It becomes possible to form a part having it.

(Third embodiment)
FIG. 3 is a sectional view showing a third embodiment of the present invention. In FIG. 3, the same parts as those in FIG. The difference from FIG. 1 is that the end of the phosphor protective layer 113, which is an ultraviolet cross-linked adhesive sheet, is pressed as shown in FIG. Further, after pressurizing the end portion of the phosphor protective layer 113, the cross-linking reaction of the pressure sensitive adhesive sheet resin proceeds in the end region irradiated with the ultraviolet ray in the same manner as in FIG. It is possible to form a portion having a similar effect.

  Here, since the phosphor protective layer 113 has shape followability, it is preferable that the phosphor protective layer 113 is formed along the uneven shape of the phosphor by applying pressure from above when the phosphor protective layer 113 is bonded to the phosphor layer. In addition, if the protective layer 113 is pressed with a pressure block at the portion where the phosphor protective layer 113 is in direct contact with the sensor panel 100 to reduce the thickness of the protective layer, the resin from the end of the sheet can be made thinner, so that moisture from the outside can permeate. It is difficult and preferable. Therefore, durability can be further improved.

(Fourth embodiment)
4 to 6 are cross-sectional views showing a fourth embodiment of the present invention. 4 to 6, the same parts as those in FIG. In the present embodiment, after the phosphor protective layer 113 (ultraviolet crosslinking adhesive sheet) covering the phosphor layer 112 is placed on the phosphor layer 112, the phosphor protective layer is pressed from above as shown in FIG. 113 is formed by fluidizing into the shape of the phosphor layer 112.

  Next, as shown in FIG. 5, the entire surface of the phosphor protective layer 113 is cured by irradiating ultraviolet rays from the upper surface. Further, as shown in FIG. 6, a moisture-proof protective layer 114 is bonded to the cured phosphor protective layer 113 via an adhesive material 117.

  In the above-described embodiment, the case where a photoelectric conversion element portion including a photosensor using amorphous silicon and a TFT is formed on a glass substrate as a two-dimensional photodetector has been described. It is also possible to configure the radiation detection apparatus as appropriate by using a semiconductor single crystal substrate on which the image pickup elements arranged in a dimension are formed and disposing an underlayer and a phosphor layer thereon. Further, the present invention is not limited to a sensor panel in which photoelectric conversion elements are arranged two-dimensionally, and can be used in a one-dimensional case.

(Fifth embodiment)
FIG. 7 is a conceptual diagram showing an embodiment of a radiation imaging system using the radiation detection apparatus of the present invention. X-rays 6060 generated by the X-ray tube 6050 pass through the chest 6062 of the patient or subject 6061 and enter the radiation detection apparatus (image sensor) 6040 according to the present invention as described above. The incident X-ray includes information inside the body of the patient or subject 6061.

  The above-described phosphor layer emits light in response to the incidence of X-rays, and the photoelectric conversion element of the sensor panel performs photoelectric conversion to obtain electrical information. This information is converted into digital information, subjected to image processing by an image processor 6070 which is a signal processing means, and can be observed on a display 6080 which is a display means installed in the control room.

  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 installed in a doctor room or the like in another place. Further, it can be stored in a recording means such as an optical disk and can be diagnosed by a remote doctor. Furthermore, it can also record on the film 6110 by the film processor 6100 used as a recording means.

  Next, examples of the present invention will be described.

Example 1
In Example 1, the sensor panel 100 was formed as shown in FIG. 1, and the phosphor layer 112 and the phosphor protective layer 113 were formed on the sensor panel 100. Specifically, a photoelectric conversion element portion 103 and a wiring portion 102 made of a photosensor and a TFT are formed on a glass substrate 101 using amorphous silicon, and a first protective film 105 made of silicon nitride is formed thereon. The electrode extraction part 104 was formed. Further, the second protective film 106 made of polyimide was formed on the first protective film 105 to obtain the sensor panel 100.

  Next, surface treatment by plasma treatment was performed on the second protective film 106. The plasma treatment was performed using an atmospheric pressure plasma cleaning apparatus (Matsushita Electric Works and Vision Co., Ltd.) with a reaction tube width of 75 mm, an irradiated distance of 5 mm, an operation speed of 75 mm, and an output of 0.8 kW.

  Next, CsI: Tl (thallium activated cesium iodide) was deposited at a position corresponding to the pixel region of the second protective film 106 to obtain the phosphor layer 112.

Next, a phosphor protective layer 113 made of an ultraviolet-crosslinked acrylic pressure-sensitive adhesive sheet having a thickness of 100 μm was laminated on the Al surface side of an Al / pet sheet in which Al 40 μm and PET 50 μm were laminated. Further, a sheet in which the phosphor protective layer / Al / PET was laminated was disposed on the surface of the sensor panel 100 on which the phosphor layer 112 was formed, and the sheets were laminated by applying 3 kgf / cm ² pressure. The phosphor protective layer was laminated with a width of 3 mm around the outer edge of the sensor panel.

Furthermore, 400 mJ / cm ² of ultraviolet light is irradiated from the back surface of the sensor panel to the glass surface from the end of the phosphor protective layer to crosslink the end of the phosphor protective layer to obtain a sensor panel in which the phosphor layer 112 is directly formed. It was. Furthermore, the terminal part of the flexible circuit board (not shown) was thermocompression bonded to the electrode extraction part 104 on the sensor panel 100 via an anisotropic conductive adhesive (not shown) to obtain a radiation detection apparatus. The Al / pet sheet becomes the moisture-proof protective layer 114.

(Example 2)
In Example 2, the sensor panel 100 was formed as shown in FIG. 3, and the phosphor layer 112 and the phosphor protective layer 113 were formed on the sensor panel. At that time, the phosphor protective layer / Al / Pet was laminated on the phosphor layer 112 in the same manner as in Example 1. The end of the phosphor protective layer was bonded to the sensor panel at an outer peripheral part of 5 mm. Further, the end of the phosphor protective layer was pressed with a pressure block having a width of 2 mm until the phosphor protective layer had a thickness of 25 microns. This pressurization differs from Example 1.

In addition, the sensor panel on which the phosphor layer 112 is directly formed is obtained by irradiating 400 mJ / cm ² of ultraviolet light from the back surface of the sensor panel through the glass surface to the glass surface to crosslink the phosphor protection layer end portion. It was. Furthermore, the terminal part of the flexible circuit board (not shown) was thermocompression bonded to the electrode extraction part 104 on the sensor panel 100 via an anisotropic conductive adhesive (not shown) to obtain a radiation detection apparatus. Al / Pet becomes a moisture-proof protective layer.

(Example 3)
In Example 3, the sensor panel 100 was formed as shown in FIG. 4, and the phosphor layer 112 and the phosphor protective layer 113 were formed on the sensor panel. At that time, a fluorescent protective layer of an ultraviolet cross-linked pressure-sensitive adhesive sheet was laminated on a release film (not shown), and 3 kgf / cm ^{2 was} pressed from above the release film in a state where it covered the fluorescent layer 112. Next, after removing the release film, the phosphor protective layer was obtained by irradiating 400 mJ / cm ² of ultraviolet rays from the phosphor protective layer surface side as shown in FIG.

  Furthermore, as shown in FIG. 6, a laminated sheet made of Al / PET (moisture-proof protective layer) was bonded to the phosphor protective layer via an adhesive so as to face the Al surface side. Moreover, the terminal part of the flexible circuit board (not shown) was thermocompression-bonded to the electrode extraction part 104 on the sensor panel 100 via an anisotropic conductive adhesive (not shown), and the radiation detection apparatus was obtained.

(Comparative Example 1)
In Comparative Example 1 (FIG. 8), a photoelectric conversion element portion 103 and a wiring portion 102 made of a photosensor and TFT using amorphous silicon are formed on a glass substrate 101, and a first protection made of SiNX is formed thereon. A film 105, a second protective film 106 made of polyimide resin, and an electrode extraction portion 104 were formed. Next, CsI: Tl was vapor-deposited at a position corresponding to the pixel region composed of the plurality of photoelectric conversion element portions 103 of the second protective layer 106 to obtain the phosphor layer 112.

  Furthermore, 15 μm of polyparaxylylene resin was deposited by a thermal CVD method to form the phosphor protective layer 113. In addition, after a sheet of Al 40 μm and PET 50 μm is laminated with an acrylic adhesive, an acrylic UV curable resin is applied as a sealing resin by a dispenser and cured to form the sealing resin, and the phosphor layer 112 is directly formed. Obtained sensor panel. Furthermore, the terminal part of the flexible circuit board (not shown) was thermocompression bonded to the electrode extraction part 104 on the sensor panel 100 via an anisotropic conductive adhesive (not shown) to obtain a radiation detection apparatus.

  The radiation detectors produced in Examples 1, 2, and 3 were endured for 3000 hours at a temperature of 50 degrees and a relative humidity of 90%, but no change was observed in the images. On the other hand, in the radiation detection apparatus obtained in Comparative Example 1, there was a case where an image defect due to a phosphor defect due to moisture intrusion occurred from the edge of the image region. Further, when the ball drop impact test (JIS K7211 sphere 1 type 0.5 kg 500 mm) was repeatedly performed using the samples of Examples 1, 2, 3 and Comparative Example 1, the samples of Comparative Examples 1 and 2 were used. In some cases, image defects that may be caused by the deformation of the phosphor were observed.

  The present invention can be used for a radiation detection apparatus and a scintillator panel used in medical diagnostic equipment, non-destructive testing equipment, and the like.

It is sectional drawing which shows the 1st Embodiment of this invention. It is sectional drawing which shows the 2nd Embodiment of this invention. It is sectional drawing which shows the 3rd Embodiment of this invention. It is sectional drawing which shows the 4th Embodiment of this invention. It is sectional drawing which shows the 4th Embodiment of this invention. It is sectional drawing which shows the 4th Embodiment of this invention. It is a conceptual diagram which shows one Embodiment of the radiation imaging system using the radiation detection apparatus of this invention. It is sectional drawing which shows the radiation detection apparatus of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Sensor panel 101 Glass substrate 102 Wiring part 103 Photoelectric conversion element part 104 Electrode extraction part (electrode pad part)
DESCRIPTION OF SYMBOLS 105 1st protective film 106 2nd protective film 111 Phosphor adhesion layer 112 Phosphor layer 113 Phosphor protective layer 114 Moisture-proof protective layer 115 Adhesive material 116 UV cross-linked adhesive sheet 117 Adhesive material 204 Sealing resin

Claims (4)

A sensor panel having at least a photoelectric conversion unit having a plurality of photoelectric conversion elements arranged one-dimensionally or two-dimensionally on a substrate;
A phosphor layer that is disposed on the sensor panel corresponding to the photoelectric conversion unit and has a phosphor that converts radiation into light that can be sensed by the photoelectric conversion element;
A phosphor protective layer covering at least the surface and side surfaces of the phosphor layer and a partial surface of the sensor panel;
In a radiation detection apparatus having
The radiation detection apparatus according to claim 1, wherein at least a portion of the phosphor protective layer that is in contact with a part of the surface of the sensor panel is made of an ultraviolet-crosslinking adhesive member. The radiation detection apparatus according to claim 1, wherein the phosphor layer is made of an alkali halide phosphor having a columnar crystal structure. The radiation detection apparatus according to claim 1, wherein the phosphor layer is made of an alkali halide phosphor having a columnar crystal structure, which is directly formed on the sensor panel by vapor deposition. The radiation detection apparatus according to any one of claims 1 to 3,
Signal processing means for processing signals from the radiation detection device;
Recording means for recording a signal from the signal processing means;
Display means for displaying a signal from the signal processing means;
Transmission processing means for transmitting a signal from the signal processing means;
A radiation imaging system comprising: a radiation source for generating the radiation.

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