JP2002228757A - Radiation detector and wave length converter for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation detector with improved resolution and having excellent mass-productivity and causing no positional displacement, and to provide a wave length converter used for the same. SOLUTION: This radiation detector is provided with a light detector 22 for detecting radiation and a phosphor layer 24 as a wave length converter. The light detector 22 has picture elements 1 and an adhesive agent layer 21. The phosphor layer 24 has cell walls 17, phosphor 20 as a wave length converting part, adhesive agent layer 18, a cell base 16, cell openings 23, alignment marks 3, and openings 19 for alignment. A substrate 2 of the light detector 22 is formed of a low alkali glass having 0.7 mm of thickness. Outline of the substrate 2 is 500 mm×500 mm. As a material for the cell wall 17, an ultraviolet rays hardening resin having at least acryloile group is used. PEN is used for the cell base 16. PEN is a transparent resin having 3×10-5/ deg.C of coefficient of thermal expansion. As a reflecting layer 18, a gold deposition film is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation detector and a wavelength converter used therewith, and more particularly to a radiation detector having a plurality of pixels and a wavelength converter used therewith.

[0002]

2. Description of the Related Art Conventionally, various methods have been devised for detecting radiation (X-rays, α-rays, β-rays, γ-rays, etc.) by combining a photodetector and a wavelength converter.

[0003] By dividing the photodetector into a plurality of pixels, position information or image information can be obtained. At this time, if there is a uniform phosphor on the adhesive surface of the wavelength converter to the photodetector, unnecessary fluorescent light will enter not only the photodetector immediately below but also the adjacent photodetector and the image will be displayed. Causes the resolution of the image to be reduced.

In order to prevent the resolution of the image from lowering,
For example, in Japanese Patent Application Laid-Open No. 53-96789, an Al plate is provided as a partition plate for preventing light leakage between pixels of a photodetector made of a silicon substrate.
A phosphor is buried here to prevent a reduction in resolution.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. Hei 5-60871, a phosphor is buried in a concave portion of a silicon substrate having a plurality of concave portions formed by a photolithography process, and this is used as a photodetector having a plurality of pixels. By lowering the resolution by preventing the radiation detector from being attached to the container and making each pixel correspond to the concave portion, a reduction in resolution is prevented.

[0006] Further, as a material and a manufacturing method for forming a concave portion corresponding to a pixel of a photodetector, besides this, see Japanese Patent Application Laid-Open No. 9-615.
No. 36 discloses a nickel metal mesh, and U.S. Pat. No. 5,952,665 discloses a method in which glass, silicon and polysilicon are perforated by etching.

Although the correspondence with the pixel is not disclosed,
For example, as disclosed in Japanese Patent Application Laid-Open No. 55-67700, a silicon matrix is molded by injecting white silicon rubber containing titanium dioxide (TiO ₂ ) or by exposing and developing a photosensitive resin. Things are disclosed.

In Japanese Patent Application Laid-Open No. 5-31049,
A Teflon (registered trademark) substrate in which a concave portion corresponding to a pixel is formed by cutting is disclosed. However, since the size of one pixel is 1 mm × 1 mm × 20 mm, which is relatively large, a general manufacturing method can be applied as it is. Can not.

Japanese Patent Application Laid-Open No. 9-61535 discloses a wavelength converter in which a strength maintaining plate made of carbon graphite is attached to one side of a light-shielding mesh plate, and a phosphor is separated and filled in an opening of the mesh. And a photodetector,
There is disclosed a radiation detection apparatus in which the strength of the base is not weakened even when the aperture ratio is increased by laminating through an adhesive layer, and image unevenness due to deflection of handling or the like does not occur.

[0010]

However, in the devices disclosed in the above-mentioned publications and the like, if a partition plate, a concave portion, or a mesh for separating and packing the phosphor is manufactured by cutting a metal or a resin, it takes a long time. It is difficult to mass-produce. Further, a method of forming a concave portion in a silicon substrate using a photolithography process is costly.
Further, if the metal is etched to about 400 μm, it takes a long time to manufacture the metal.

In order to solve this problem, molding with a resin that is relatively inexpensive and can be manufactured with good mass productivity can be considered.
Since the 400 μm mesh is unthinkably thin, even if it is molded with a resin, the resin will be broken or the shape will be lost when peeled from the mold. Therefore, it is difficult to maintain the shape only with such a resin, so after injecting the resin into the mold,
It is hardened by covering it with a reinforcing plate such as carbon graphite.

However, if the reinforcing plate is opaque like carbon graphite, it can be heat-cured, but cannot be manufactured using a photo-curing process with good mass productivity.

Further, the reinforcing plate is required to have a property that the expansion and contraction due to heat is small in order to prevent the displacement between the photodetector and the wavelength converter.

That is, a resin manufactured by a manufacturing method with good mass productivity is used for both the partition plate and the reinforcing plate, and a material that is stable against heat and has high transparency is used for the reinforcing plate. Needed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a radiation detection apparatus which is rich in mass productivity, does not generate positional deviation, and has improved resolution, and a wavelength converter used therefor.

[0016]

According to the present invention, there is provided a wavelength converter for converting radiation into light, and a photodetector for detecting the light are bonded to each other via an adhesive layer. In a radiation detecting apparatus, wherein the wavelength converter has a light-shielding cell having an opening corresponding to a pixel of the photodetector, and a wavelength converter filled in the opening, the light-shielding cell includes It is composed of a base on the incident side and a cell wall on the side from which the light is emitted. The base is a material that transmits ultraviolet light, and the cell wall is a UV-curable resin.

A wavelength converter for converting radiation into light;
The photodetector for detecting the light is attached via an adhesive layer, the wavelength converter is a light-shielding cell having an opening corresponding to a pixel of the photodetector, and a wavelength filled in the opening. In the radiation detection device having the conversion unit, the light-shielding cell includes a base on which the radiation is incident and a cell wall on the side from which the light is emitted. It is a material having an expansion coefficient of 3 × 10 ⁻⁵ / ° C. or less, and the cell wall is made of an ultraviolet curable resin.

[0018] Further, the present invention for solving the above-mentioned problems,
A light-shielding cell having an opening corresponding to a pixel of the photodetector, which is attached to the photodetector through an adhesive layer, and a wavelength conversion portion filled in the opening, and converts radiation into light. In the wavelength converter for conversion, the light-shielding cell includes a substrate on the side on which the radiation is incident, and a cell wall on the side on which the light is emitted, and the substrate is a material that transmits ultraviolet light, The wall is a UV curable resin.

The light-shielding cell includes a light-shielding cell bonded to the photodetector via an adhesive layer and having an opening corresponding to a pixel of the photodetector, and a wavelength converter filled in the opening. In a wavelength converter for converting radiation into light, the light-shielding cell includes a base on which the radiation enters, and a cell wall on which the light exits, and the base transmits ultraviolet light. And a material having a coefficient of thermal expansion of 3 × 10 ⁻⁵ / ° C. or less, and the cell wall is made of an ultraviolet curing resin.

[0020]

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

FIG. 1 is a schematic sectional view showing an embodiment of the radiation detecting apparatus according to the present invention.

Reference numeral 22 denotes a photodetector for detecting radiation (X-ray, α-ray, β-ray, γ-ray, etc.), and reference numeral 24 denotes a phosphor layer as a wavelength converter. In the photodetector 22, 1 is a pixel, 21
Is an adhesive layer. In the phosphor layer 24, 17 is a cell wall, 20 is a phosphor as a wavelength conversion unit, 18 is an adhesive layer,
Reference numeral 16 denotes a cell base, 23 denotes a cell opening, 3 denotes an alignment mark, and 19 denotes an alignment opening.

FIG. 2 is a schematic plan view showing the photodetector 22 shown in FIG.

In FIG. 2, pixels 1 are arranged vertically and horizontally at a pitch of 160 μm. The size of each pixel 1 is 130
μm, and the pixel interval is 30 μm. Photodetector 22
The substrate 2 is made of a low alkali glass having a thickness of 0.7 mm (for example, 7059 glass manufactured by Corning Incorporated).
Further, on the glass substrate 2, there is an alignment mark 3 used for bonding with the phosphor layer 24 shown in FIG. The outer shape of the substrate 2 is 500 mm × 500 mm.

FIG. 3 shows the photodetector 22 shown in FIGS.
3 is a plan view showing one pixel of FIG.

When the sensor unit 4 and the TFT unit 5 are turned on, the signal charges stored in the sensor unit 4 are transmitted to the signal line 7 and are read as image signals. Finally, by resetting the sensor unit 4 by the common reset line 8, one image reading is completed.

FIG. 4 is a schematic sectional view showing one pixel of the photodetector 22 shown in FIG.

The photodetector 22 has a gate electrode 9 (100 nm) made of Cr and a plasma nitride film 10 (300 nm).
m), hydrogenated amorphous silicon layer 11 (500 n
m), a doping semiconductor layer 12 (50 nm), and an aluminum film 13 (1000 nm). The sensor section 14 and the TFT section 15 are formed of the same hydrogenated amorphous silicon layer.

The present invention is also applicable to a photodetector having another structure using hydrogenated amorphous silicon and a photodetector using crystalline silicon.

Next, a method for manufacturing the phosphor layer used in the present embodiment will be described.

FIG. 5 is a schematic plan view showing the phosphor layer 24 shown in FIG.

In FIG. 5, as a material of the cell wall 17, an ultraviolet curable resin having at least an acryloyl group is used. In this embodiment, urethane acrylate is used. The structure of the acryloyl group is (CH ₂ ＣＨCHCO
−). Among those having an acryloyl group, acrylamide, acrylonitrile, acrylic acid, acrylate and the like are used.

FIGS. 6 and 7 show the phosphor layer 24 shown in FIG.
It is a schematic sectional drawing which shows the manufacturing process of.

First, in FIG. 6, urethane acrylate was poured into a mold for the cell wall 17, and a 0.1 mm sheet of PEN (polyethylene naphthalate resin) used as a cell base 16 was covered with good adhesion. Then, it was light-cured and removed from the mold described above.

As a mold for forming the cell wall 17, it is desirable to use a mold made by metal plating such as electroforming. The reason is that in the case of the resin mold, the mold release from the molding resin is not good.

As described above, PEN is used for the substrate 1 of the cell.
6, that is, used as a reinforcing plate. PEN has a coefficient of thermal expansion of 1
Although it is a transparent resin of × 10 ^-5 / ° C, it is also preferable to use PET (polyethylene terephthalate) for the base 16. The material of the base 16 has a coefficient of thermal expansion of 3
^Any transparent material having a ^{density of 10-5} / C or less may be used.

When the radiation detecting apparatus is photographed in accordance with the human body, it is desirable that the sensor used has a size of 30 cm to 50 cm square. Considering general manufacturing conditions, that is, bonding of sensor panels in a clean room having a temperature difference of ± 1 ° C., the coefficient of thermal expansion is 3
With a resin of × 10 ^-5 / ° C, a difference of 18 to 30 µm occurs at 2 ° C. The pitch of one pixel of the photodetector 22 is 100 μm,
Assuming that the photosensitive area in one pixel is 85 μm (when one pixel is 100 μm), the allowable range of expansion and contraction due to heat is 15 μm.
m or less (15% or less).
There is an effect on the resolution of the photodetector.

Therefore, in the present embodiment, it is appropriate to set the above-mentioned coefficient of thermal expansion to 3 × 10 ⁻⁵ / ° C. or less.

However, once the phosphor layer 24 and the photodetector 22 are bonded together, the glass 2
Therefore, it is not necessary to consider expansion and contraction during use.

In this embodiment, a transparent resin is used as the material of the base 16. This transparent resin has a wavelength of 250 to 5
It is a resin material having a transmittance of 00 nm light of 20% or more.
Therefore, UV (ultraviolet) light for curing the ultraviolet curing resin having an acryloyl group, which is the material of the cell wall 17, is transmitted.

The openings 23 of the cells correspond one-to-one with the pixels 1 of the photodetector 22, and are arranged vertically and horizontally at a pitch of 160 μm. The size of the opening 23 is 130
× 130 μm. Also, an opening 19 for alignment is provided.
Are provided for alignment with the light detection substrate.

This cell has a reflective layer 1 made of a metal thin film.
8 are provided. In addition, a gold vapor deposition film was used for the reflection layer 18.

Next, as shown in FIG. 7, a paste 20 in which a fine powder of a phosphor is dispersed in a resin binder is poured between the cell walls 17, ie, between the meshes.

Subsequently, the surface of the mesh is flattened with a squeegee and then heated to polymerize the binder resin. Thus, the phosphor layer 24 shown in FIG. 1 is completed.

Next, as shown in FIG. 1, the phosphor layer 24 and the photodetector 22 are bonded via the bonding layer 21. At this time, the pixel 1 and the phosphor layer 24 are aligned using the alignment mark 3 and the opening 19 for alignment.

[0046]

As described above, according to the radiation detector of the present invention and the wavelength converter used therefor, since the cell wall can be manufactured by molding, it is rich in mass productivity, and the substrate is made of a material which transmits ultraviolet rays. Because of this, it can be used without any inconvenience even during ultraviolet curing, and since the coefficient of thermal expansion is small, there is no displacement between the photodetector and the wavelength converter, and the resolution of the image is improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a radiation detection device according to the present invention.

FIG. 2 is a schematic plan view showing the photodetector 22 shown in FIG.

FIG. 3 is a plan view showing one pixel of the photodetector 22 shown in FIGS. 1 and 2;

FIG. 4 is a schematic cross-sectional view showing one pixel of the photodetector 22 shown in FIG.

FIG. 5 is a schematic plan view showing a phosphor layer 24 shown in FIG.

FIG. 6 is a schematic cross-sectional view showing a manufacturing process of the phosphor layer 24 shown in FIG.

7 is a schematic cross-sectional view showing a manufacturing process of the phosphor layer 24 shown in FIG. 1 together with FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photodetector pixel 2 Photodetector substrate 3 Alignment mark 4 Sensor part 5 TFT 6 Gate line 7 Signal line 8 Common reset line 9 Gate electrode 10 Plasma nitride film 11 Hydrogenated amorphous silicon layer 12 Doping semiconductor layer 13 Aluminum film DESCRIPTION OF SYMBOLS 14 Sensor part 15 TFT part 16 Substrate 17 Cell wall 18 Reflection layer 19 Alignment opening 20 Paste 21 Adhesive layer 22 Photodetector 23 Cell opening 24 Phosphor layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomoyuki Tamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yoshihiro Ogawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon F Term in Reference (Reference) 2G088 FF02 FF04 FF05 FF06 GG19 JJ05 JJ09 JJ37 5F088 AA11 AB05 BA20 BB07 EA04 EA08 HA15 LA08

Claims (15)

[Claims] 1. A wavelength converter for converting radiation into light and a photodetector for detecting the light are adhered via an adhesive layer, and the wavelength converter is provided with an aperture corresponding to a pixel of the photodetector. In a radiation detecting apparatus having a light-shielding cell having a portion and a wavelength converter filled in the opening, the light-shielding cell is a base on which the radiation is incident,
The radiation detection device, comprising: a cell wall on a side from which the light is emitted; the base is made of a material that transmits ultraviolet light; and the cell wall is made of an ultraviolet curable resin. 2. The radiation detection apparatus according to claim 1, wherein the wavelength conversion unit has a phosphor. 3. A wavelength converter for converting radiation into light and a photodetector for detecting the light are bonded together via an adhesive layer, and the wavelength converter is provided with an aperture corresponding to a pixel of the photodetector. In a radiation detecting apparatus having a light-shielding cell having a portion and a wavelength converter filled in the opening, the light-shielding cell is a base on which the radiation is incident,
The substrate is made of a material that transmits ultraviolet light and has a coefficient of thermal expansion of 3 × 10 ⁻⁵ / ° C. or less, and the cell wall is made of an ultraviolet-curable resin. A radiation detection device characterized by the above-mentioned. 4. The radiation detecting apparatus according to claim 1, wherein the base is made of a material that transmits 20% or more of light having a wavelength of 250 to 500 nm. 5. The radiation detecting apparatus according to claim 1, wherein the ultraviolet curable resin on the cell wall has an acryloyl group. 6. The radiation detecting apparatus according to claim 5, wherein the ultraviolet curing resin having an acryloyl group is acrylamide, acrylonitrile, acrylic acid or acrylate. 7. The radiation detecting apparatus according to claim 1, wherein the radiation is an X-ray. 8. The radiation detecting apparatus according to claim 1, wherein the wavelength converter is filled in the opening via a metal reflecting the incident radiation. 9. A light-shielding cell bonded to a photodetector through an adhesive layer and having an opening corresponding to a pixel of the photodetector, and a wavelength conversion unit filled in the opening. In a wavelength converter for converting radiation into light, the light-shielding cell includes a substrate on a side on which the radiation is incident,
A wavelength converter, comprising: a cell wall on a side from which the light is emitted; the base is made of a material that transmits ultraviolet light; and the cell wall is made of an ultraviolet curable resin. 10. A light-shielding cell bonded to a photodetector via an adhesive layer and having an opening corresponding to a pixel of the photodetector, and a wavelength converter filled in the opening. In a wavelength converter for converting radiation into light, the light-shielding cell includes a substrate on a side on which the radiation is incident,
The substrate is made of a material that transmits ultraviolet light and has a coefficient of thermal expansion of 3 × 10 ⁻⁵ / ° C. or less, and the cell wall is made of an ultraviolet-curable resin. A wavelength converter characterized in that: 11. The wavelength converter according to claim 9, wherein the substrate is made of a material that transmits 20% or more of light having a wavelength of 250 to 500 nm. 12. The wavelength converter according to claim 9, wherein the ultraviolet-curable resin on the cell wall has an acryloyl group. 13. The radiation detecting apparatus according to claim 12, wherein the ultraviolet curable resin having an acryloyl group is acrylamide, acrylonitrile, acrylic acid or acrylate. 14. The wavelength converter according to claim 9, wherein the radiation is X-rays. 15. The radiation detection apparatus according to claim 9, wherein the wavelength conversion unit is filled in the opening via a metal that reflects the incident radiation.