JP2003262671A - Scintillator panel and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scintillator panel and a method for manufacturing it, which can more effectively suppress degradation due to a scintillator component of a metal reflection film. <P>SOLUTION: A protective organic film 12 is provided and covers the metal reflection film 11 provided no a substrate 10, further covers the sidewalls of the substrate 10 and reaches at least the edges of the back face. After a scintillator 13 is selectively formed on an upper part corresponding to the metal reflection film 11 through deposition, the scintillator 13 and the scintillator component attached to the outside of a selected region are covered with a moisture resistant protective film 14. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scintillator panel used for medical and industrial X-ray imaging and a method for manufacturing the scintillator panel.

[0002]

2. Description of the Related Art Conventionally, in medical and industrial X-ray photography, X
Although a line-sensitive film has been used, a radiation imaging system using a radiation detector has become widespread in terms of convenience and preservation of imaging results. In such a radiation imaging system, a radiation detector
Pixel data by three-dimensional radiation is acquired as an electric signal, and this signal is processed by a processing device and displayed on a monitor.

A typical radiation detector is a radiation detector having a structure in which a scintillator panel is formed by forming a scintillator on a substrate made of aluminum, glass, fused silica or the like, and the scintillator panel and the image sensor are attached to each other. Exists.
In this type of radiation detector, radiation incident from the substrate side is converted into light by a scintillator and detected by an image sensor (see Japanese Patent Publication No. 7-21560).

Further, in order to increase the light output of the scintillator panel, as shown in FIG. 10, the surface opposite to the light output surface of the scintillator 13 (here, the substrate 10 side).
The metal reflective film 11 is provided on the protective film 12 in order to prevent the metal reflective film 11 from contacting the scintillator 13 to deteriorate due to the components of the scintillator 13.
There is a scintillator panel 1x having a structure covered with (Patent No. 3126715). The scintillator 13 is covered with a moisture-proof film 14 to prevent the scintillator 13 from moisture.

[0005]

The inventors of the present invention, when creating a large-screen scintillator panel 1x with this structure,
Since the metal reflective film 11 is rarely deteriorated, the present invention has been achieved as a result of studying a method of effectively suppressing this deterioration. That is, an object of the present invention is to provide a scintillator panel and a method for manufacturing the scintillator panel, which can more effectively suppress the deterioration of the metal reflection film due to the scintillator component.

[0006]

As a result of detailed investigation of the scintillator panel in which the deterioration of the metal reflection film has occurred, the present inventors have obtained the following findings. When the scintillator 13 is formed by vapor deposition, even if a mask or the like is used so that the scintillator 13 is formed only on the portion of the metal reflection film 11 covered with the protective film 12, the scintillator component may be wrapped around the mask. Substrate 1 whose substrate is not covered by the protective film 12
It may adhere to the side wall of 0. The attached scintillator component penetrates between the protective film 12 and the substrate 10 and reaches the metal reflection film 11 inside, and corrodes the metal reflection film 11.

Therefore, in order to surely prevent the scintillator component which may adhere during such vapor deposition from reaching the metal reflection film, the scintillator panel according to the present invention includes a radiation transmissive substrate and one surface of the substrate. Formed as a large number of needle-shaped crystals by vapor deposition on the metal reflective film formed above, the protective organic film covering the metal reflective film and covering at least the side wall of the substrate, and the protective organic film on the metal reflective film The alkali halide-based scintillator, and a moisture-proof organic film that covers the scintillator are provided, and the protective organic film prevents the scintillator component from adhering to the substrate and the metal reflective film during vapor deposition of the scintillator, and the moisture-proof organic film. Covers the scintillator component attached on the protective organic film.

On the other hand, the method of manufacturing a scintillator panel according to the present invention comprises a step of forming a metal reflection film on one surface of a radiation transmissive substrate and a step of forming the metal reflection film from at least one surface of the substrate. A step of forming a protective organic film covering up to the side wall thereof, and the protective organic film prevents adhesion of the scintillator component to the metal reflection film and the substrate,
A step of forming a scintillator by growing a large number of needle-like crystals by depositing an alkali halide scintillator component only on a predetermined portion of the protective organic film surface on the metal reflection film, and the scintillator and outside the predetermined portion. And a step of forming a moisture-proof organic film that covers the attached scintillator component.

As described above, since the protective organic film covering the metal reflective film covers the metal reflective film formation surface of the substrate to the side wall of the substrate, the protective organic film is more firmly adhered to the substrate, and the substrate and the protective organic film. It is possible to reliably suppress the formation of a gap between which the scintillator component can penetrate. Then, as the scintillator panel becomes larger and the effective image area becomes larger, the protective organic film adheres to the substrate at the side wall even when the metal reflection film is formed on almost one surface of the substrate. Thus, the peeling from the peripheral portion of the protective organic film can be reliably prevented. By using the organic film, it is easy to form a uniform film from the substrate surface to the side wall. The scintillator component that wraps around the mask during vapor deposition does not reach the back surface of the substrate (the surface opposite to the scintillator formation surface), and even if it adheres, it remains on the protective organic film. Then, by covering the scintillator and the scintillator component adhered on the protective organic film with the moisture-proof organic film, the scintillator component adhered on the protective organic film does not move to another. Therefore, it is possible to reliably prevent the scintillator component from penetrating into the metal reflective film.

It is preferable that the protective organic film substantially covers the other surface (back surface) of the substrate. This makes it possible to prevent the protective organic film from peeling off, and more reliably prevent the scintillator component or moisture from penetrating into the gap between the protective organic film and the substrate.

Further, the protective organic film is preferably an organic film formed by vapor phase growth. By forming the organic film by vapor deposition, a uniform film that reaches the side wall of the substrate from above the metal reflection film can be easily and stably manufactured.

Alternatively, the protective organic film comprises a first protective organic film on the side of the metal reflection film and a second protective organic film on the side of the substrate, and the peripheral portion of the first protective organic film is the second protective organic film. The film and the metal reflection film may be laminated at the peripheral portion or outside thereof.

Such a protective organic film (1) forms a first protective organic film that covers the metal reflective film and at least covers the surface of the substrate exposed around the metal reflective film. Forming a frame-shaped second protective organic film from the peripheral edge of the protective organic film to the side wall of the substrate, or (2) forming a frame-shaped second protective organic film from the side wall of the substrate to the peripheral edge of the metal reflection film.
First protective organic film is formed, then the metal reflective film is covered and the second protective organic film is laminated at the peripheral edge of the metal reflective film.
Can be formed by forming a protective organic film.

As described above, the first protective organic film that mainly covers the metal reflection film on the front surface side of the substrate and the second protective organic film that mainly covers the side wall of the substrate are provided, and the peripheral portion of the metal reflection film or By stacking these protective organic films on the outer side thereof, when the organic film is formed by coating or the like, the shielding property from the metal reflective film to the side wall of the substrate can be ensured.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In order to facilitate understanding of the description, the same reference numerals are given to the same constituent elements in each drawing as much as possible in the drawings, and redundant description will be omitted. In addition, in order to facilitate understanding of the description, each drawing is exaggerated or omitted, and a dimensional ratio thereof does not necessarily match an actual one.

FIG. 1 is a sectional view showing the first embodiment of a scintillator panel according to the present invention. The scintillator panel 1 includes a radiation transparent substrate 10 (glass,
A metal reflection film 11 is formed on one surface of (amorphous carbon or other material containing carbon as a main component). The metal reflection film 11 is made of Al, Ag, Cr, C.
It consists of materials in u, Ni, Ti, Mg, and Rh. A protective organic film 12 is formed on the metal reflection film 11 so as to surround the substrate 10. This protective organic film 12 is
For example, it consists of polyparaxylylene. Metal reflective film 11
A scintillator 13 is formed on the surface of the laminated portion of the protective organic film 12 to convert radiation that has passed through the substrate 10 and is incident into visible light. For this scintillator 13, for example, Tl-doped CsI is used. CsI has a structure in which a large number of needle-shaped crystals stand. The scintillator 13 is covered with the substrate 10 by a moisture-proof organic film 14 made of polyparaxylylene.

Next, the manufacturing process of the scintillator panel 1 will be described with reference to FIGS. First, a rectangular or circular substrate 10 (thickness 1 mm) is prepared (see FIG.
(See (a)), the metal reflection film 11 is formed on the surface by vacuum deposition.
Is formed with a thickness of 150 nm (see FIG. 2B).

Next, a protective organic film 12 made of polyparaxylylene is formed on the metal reflection film 11 by the CVD method. That is, the substrate 10 on which the metal reflection film 11 is deposited is placed in a CVD apparatus, and the moisture-proof organic film 12 is formed on the entire surface of the substrate 10 with a thickness of 10 μm. As a result, the protective organic film 12 made of polyparaxylylene is formed so as to cover the metal reflective film 11 and substantially cover the entire periphery of the substrate reflective film 11 of the substrate 10 to the side wall and further to the back surface (FIG. 2 (c)). For the manufacturing method of this organic film, see WO99.
It is described in detail in WO / 66351.

Next, the protective organic film 12 on the metal reflection film 11
A large number of needle-like crystals of CsI doped with Tl are grown (deposited) on a predetermined region of the surface by a vapor deposition method to form a scintillator 13 with a thickness of 250 μm (see FIGS. 2D and 3). In this vapor deposition, the substrate 10 covered with the protective organic film 12 is placed in the cavity portion 20 of the vapor deposition holder 2, and an opening 21 provided in the vapor deposition holder 2 forms a portion where the scintillator 13 is to be formed on the vapor deposition chamber 4 side ( By exposing only the predetermined region), the scintillator 13 can be selectively formed substantially in the predetermined region.
The scintillator component that has passed through the opening 21, that is, CsI
It is conceivable that a part of the components may pass through the gap between the protective organic film 12 and the floor of the cavity portion 20 and adhere to the protective organic film 12 on the side wall of the substrate 10. It rarely reaches the top of 12. Board 10
It is more preferable to dispose the cover plate 3 on the back surface side and cover the back surface of the substrate 10 so that the adhesion to the back surface can be completely prevented, so that the cover plate 3 is arranged.

Cs forming the scintillator 13
I has a high hygroscopic property, and if left exposed, it absorbs water vapor in the air and deliquesces. Therefore, in order to prevent this, the moisture-proof organic film 1 further made of polyparaxylylene 1
4 (thickness 10 μm) covers the scintillator 13 to complete the scintillator panel 1 shown in FIG. The moisture-proof organic film 14 can be formed by the same manufacturing method as the protective organic film 12.

In the scintillator panel 1 of this embodiment,
The protective organic film 12 covering the metal reflection film 11 is the metal reflection film 11
Not only the front surface of the substrate 10, but also the periphery of the metal reflection film 11 of the substrate 10 to the side wall portion thereof, and further to the back surface,
Even if the scintillator component passing through the opening 21 adheres to the protective organic film 12, it is ensured that the scintillator component penetrates between the protective organic film 12 and the substrate 10 and reaches the metal reflective film 11. Can be suppressed. Therefore, it is possible to suppress deterioration of the metal reflective film 11 and improve its durability. Furthermore, the protective organic film 1
The peeling off of 2 can be surely prevented.

As shown in FIG. 1, the scintillator panel 1 has a scintillator 13 on the side opposite to the radiation incident side.
The image sensor, the television camera, etc. are disposed on the scintillator 13 side for use. Radiation enters the scintillator panel 1 from the direction of arrow A, and the moisture resistant protective film 1
4, the protective organic film 12, the substrate 10, the metal reflective film 11, and the protective organic film 12 are transmitted in this order to reach the scintillator 13, where they are absorbed by the scintillator 13 and emit visible light. Of the emitted visible light, the light directed to the substrate 10 side passes through the transparent protective organic film 12, is reflected by the metal reflection film 11, and is returned to the scintillator 13 side.
As a result, most of the light emitted from the scintillator 13 passes through the moisture resistant protective film 14 and is emitted in the arrow B direction.
An image signal corresponding to a radiation image can be obtained by capturing this optical image with an image pickup device (not shown) or a television camera.

The protective organic film 12 does not need to cover the entire back surface, but covers the side wall portion like the protective organic film 12a of the second embodiment shown in FIG. 4 and reaches the edge on the back surface side. It's enough. In this case, even if the scintillator component adheres to the back surface portion of the substrate 10 that is exposed when the scintillator 13 is vapor-deposited, the protective organic film 12a is formed on the substrate 1
Since it is in close contact with the side wall of 0, it is difficult to permeate between the protective organic film 12a and the substrate 10, and the scintillator component is covered and encapsulated by the moisture resistant organic film 14 in the subsequent step. Since it does not move thereafter, deterioration of the metal reflection film 11 can be suppressed.

5 (a) and 5 (b) are sectional views showing a third embodiment of the scintillator panel according to the present invention and a modification thereof, respectively. These embodiments differ from the first and second embodiments in that a film made of polyimide is used as the protective organic films 12b and 12b '.

Protective organic film 12 made of this polyimide
b and 12b ′ are the metal reflection film 11 shown in FIG.
After the manufacturing process of, the polyimide resin is applied to a constant thickness (10 μm) from the metal reflection film 11 to the side wall of the substrate 10.
It can be manufactured by applying and curing.

Even when the protective organic film is formed of the polyimide resin, it is necessary to reach the edge of the side wall of the substrate 10 and the edge with the back surface to form the protective organic film 12b as shown in FIG. As shown in FIG. 5 (b), the protective organic film 1
It is more preferable to form 2b 'on the back surface.

FIG. 6 is a sectional view showing a fourth embodiment of the scintillator panel according to the present invention. In this embodiment as well, as in the third embodiment, the protective organic film 1 made of polyimide is used.
2c is used, but the second protective organic film 121 in the form of a frame (frame), in which the protective organic film 12c mainly covers the side wall of the substrate 10.
And the first protective organic film 120 having a substantially flat shape that mainly covers the metal reflection film 11 is formed.

Here, the second protective organic film 121 is formed from the peripheral portion of the metal reflection film 11 to the side wall of the substrate 10, and reaches the back surface of the substrate 10 as shown in FIG. 6A. However, as shown in FIG. 6B, it is sufficient that the edge reaches the rear surface of the substrate 10.

Next, a method of manufacturing the scintillator panel 1c will be described with reference to FIGS. 2, 6 and 7. Until the metal reflection film 11 is manufactured, the manufacturing process of the scintillator panel 1 shown in FIGS. 2A and 2B is the same. After that, a polyimide resin is applied to the side wall of the substrate 10 and the substrate surface in the vicinity thereof so as to cover the peripheral edge of the metal reflection film 11 and cured, whereby the frame-shaped second protective organic film 1 is formed.
21 is formed (see FIG. 7A). Instead of applying the resin, the second protective organic film 121 may be formed by adhering the resin molded into a tape shape or a film shape.

Next, a polyimide resin is applied on the metal reflective film 11 and the second protective organic film 121 around the metal protective film 121 and cured to cure the planar first first protective organic film. 120 is formed (see FIG. 7B). After that, as in the step of FIG. 2D, a predetermined region of the surface of the protective organic film 12c (actually, the first protective organic film 120) on the metal reflection film 11 is doped with Tl in a predetermined region.
A large number of needle-shaped crystals of sI are grown (deposited) by a vapor deposition method to form a scintillator 13 (see FIG. 7C), and the scintillator 13 is covered with a moisture-proof organic film 14 made of polyparaxylylene. The scintillator panel 1c shown in 6 (a) is completed.

By thus forming the protective organic film 12c in two steps, the properties or the manufacturing method of the resin formed on the side wall portion and the metal reflection film are made different, and they can be combined so as to have suitable performances. It will be possible. In addition, when formed by coating or the like, the formation is easier than the integrated formation, and the shielding property can be ensured.

FIG. 8 is a sectional view showing a fifth embodiment of the scintillator panel according to the present invention. This embodiment is different from the fourth embodiment in that the first protective organic film 122 and the second
The order of the laminated portion of the protective organic film 123 is different. That is, in this embodiment, the second protective organic film 123 covers the peripheral portion of the first protective organic film 122.

Here, the second protective organic film 123 is formed as shown in FIG.
As shown in FIG. 8A, it is sufficient if the edge of the back surface of the substrate 10 is reached, but as shown in FIG.
It is more preferable that the back surface reaches 0. On the other hand, the first protective organic film 122 may reach the side wall of the substrate 10 as shown in FIG. Further, the second protective organic film 123 may reach the peripheral portion of the metal reflective film 11 as shown in FIG.

Next, a method of manufacturing the scintillator panel 1d will be described with reference to FIGS. 2, 8 and 9. Until the metal reflection film 11 is manufactured, the manufacturing process of the scintillator panel 1 shown in FIGS. 2A and 2B is the same. After this, first, the substrate 1 on and around the metal reflection film 11 is formed.
By coating and curing a polyimide resin on the surface 0, a planar first protective organic film 122 covering the metal reflection film 11 is formed (see FIG. 9A).

Next, a polyimide resin is applied to the side wall of the substrate 10 and the substrate surface in the vicinity thereof so as to cover the peripheral portion of the first protective organic film 122 and is cured, whereby a frame-shaped second protective organic film is formed. The film 123 is formed (see FIG. 9B). Instead of applying the resin, the second protective organic film 123 may be formed by adhering a tape-shaped or film-shaped resin.

Next, as in the step of FIG. 2D, a predetermined region on the surface of the protective organic film 12d (actually, the first protective organic film 122) on the metal reflection film 11 is doped with Tl. A large number of needle-shaped CsI-like crystals grown (deposited) by vapor deposition
To form the scintillator 13 (see FIG. 9C),
By covering the scintillator 13 with the moisture-proof organic film 14 made of polyparaxylylene, the scintillator panel 1d shown in FIG. 8A is completed.

Also in this embodiment, by forming the protective organic film 12d in two steps, the same effect as in the fourth embodiment can be obtained.

In the above description, the polyparaxylylene film is used as the moisture resistant protective film, but in addition to this, polymonochloroparaxylylene, polydichloroparaxylylene, polytetrachloroparaxylylene, polyfluoroparaxylylene. It is possible to use a xylylene-based organic film such as polydimethylparaxylylene or polydiethylparaxylylene. With these xylylene-based organic films, it is possible to form a moisture-resistant organic film that has entered the gaps between the needle-like crystals that are standing in the scintillator, and a uniform and thin film can be formed. It is possible to obtain a bright output image without deteriorating the output resolution of.

As the protective organic film, a xylylene-based organic film or other organic resin can be used as in the case of the moisture-resistant protective film. With this type of organic film,
A uniform film can be easily and reliably formed from the metal reflection film 11 to the side wall of the substrate 10. Of course, the film may be formed by a plurality of steps.

As the scintillator 13, CsI is used.
CsI (Na), NaI (Tl), L instead of (Tl)
An alkali halide-based scintillator such as iI (Eu) or KI (Tl) is suitable because it has a high radiation light conversion efficiency. On the other hand, this type of alkali halide-based scintillator component may corrode the metal reflection film 11, so the arrangement of the protective film as in the present invention is important.

[0041]

As described above, according to the present invention, by providing the protective organic film which covers the metal reflection film and further covers the side wall of the substrate and reaches at least the edge of the back surface,
When the scintillator is formed by vapor deposition, the scintillator component directly
Prevents adhesion to the side wall of the substrate and the periphery of the metal reflection film. After that, by covering the scintillator and the portion to which the scintillator component may adhere with the moisture resistant protective film 14, even if the scintillator component adheres to the moisture resistant protective film or the back surface of the substrate, the adhered component is enclosed in the moisture resistant protective film. Therefore, it can be surely prevented from penetrating between the substrate and the protective organic film and reaching the metal reflective film. Thereby, deterioration of the metal reflection film can be suppressed and durability can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing a first embodiment of a scintillator panel according to the present invention.

FIG. 2 is a diagram showing a manufacturing process of the scintillator panel of FIG.

FIG. 3 is a diagram illustrating in detail a scintillator vapor deposition process in the manufacturing process of FIG. 2;

FIG. 4 is a cross-sectional configuration diagram showing a second embodiment of a scintillator panel according to the present invention.

FIG. 5 is a cross-sectional configuration diagram showing a third embodiment of a scintillator panel according to the present invention and a modification thereof.

FIG. 6 is a cross-sectional configuration diagram showing a fourth embodiment of the scintillator panel according to the present invention and its modification.

FIG. 7 is a diagram illustrating a manufacturing process of the scintillator panel shown in FIG.

FIG. 8 is a cross-sectional configuration diagram showing a fifth embodiment of the scintillator panel according to the present invention and a modification thereof.

FIG. 9 is a diagram illustrating a manufacturing process of the scintillator panel shown in FIG.

FIG. 10 is a cross-sectional view showing a configuration of a conventional scintillator panel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scintillator panel, 2 ... Vapor deposition holder, 3 ... Cover plate, 10 ... Substrate, 11 ... Metal reflective film, 12 ... Protective film, 13 ... Scintillator, 14 ... Moisture-proof film, 121, 1
23 ... 1st protective organic film, 122,124 ... 2nd protective organic film.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koji Suzuki             1 Hamamatsuho, 1126 Nomachi, Hamamatsu City, Shizuoka Prefecture             Tonics Co., Ltd. F term (reference) 2G083 AA04 AA08 BB01 CC01 CC03                       CC04 CC05 CC08 DD01 DD02                       EE08                 2G088 EE01 FF02 GG10 GG16 GG19                       GG20 JJ05 JJ37 LL30                 5C024 AX11 AX16 CY47 EX21

Claims (8)

[Claims] 1. A radiation-transmissive substrate, a metal reflective film formed on one surface of the substrate, a protective organic film that covers the metal reflective film and covers at least a side wall of the substrate. An alkali halide scintillator formed as a large number of needle crystals by vapor deposition on the protective organic film on the metal reflection film, and a moisture-proof organic film covering the scintillator, and the protective organic film, A scintillator, characterized in that it prevents the scintillator component from adhering to the substrate and the metal reflective film during vapor deposition of the scintillator, and the moisture-proof organic film covers the scintillator component adhered on the protective organic film. panel. 2. The protective organic film substantially covers the other surface of the substrate.
The scintillator panel described. 3. The protective organic film is an organic film formed by vapor phase epitaxy.
Scintillator panel described in. 4. The protective organic film comprises a first protective organic film on the metal reflection film side and a second protective organic film on the substrate side, and a peripheral portion of the first protective organic film is the protective film. The scintillator panel according to claim 1 or 2, wherein the second protective organic film and the metal reflective film are laminated on a peripheral portion or outside thereof. 5. A step of forming a metal reflective film on one surface of a radiation transmissive substrate, and a protective organic film covering at least one surface of the substrate including the metal reflective film and its side wall. And the protective organic film prevents the adhesion of the scintillator component to the metal reflective film and the substrate, substantially only a predetermined portion of the surface of the protective organic film on the metal reflective film alkali halide system. A step of forming a scintillator by growing a large number of needle-shaped crystals by depositing a scintillator component of, and a step of forming a moisture-proof organic film covering the scintillator and the scintillator component adhering to the outside of the predetermined portion. The manufacturing method of the scintillator panel provided. 6. The method of manufacturing a scintillator panel according to claim 5, wherein the step of forming the protective organic film is performed by using vapor phase epitaxy. 7. The step of forming the protective organic film comprises the step of forming a first protective organic film which covers the metal reflective film and at least covers the surface of the substrate exposed around the metal reflective film. 6. The method of manufacturing a scintillator panel according to claim 5, further comprising the step of forming a frame-shaped second protective organic film covering a peripheral portion of the first protective organic film and a side wall of the substrate. . 8. The step of forming the protective organic film, the step of forming a frame-shaped second protective organic film covering from the side wall of the substrate to the peripheral portion of the metal reflective film; And forming a first protective organic film that is laminated on the second protective organic film at a peripheral edge portion of the metal reflective film, the manufacturing process of the scintillator panel according to claim 5. Method.