JP3956820B2 - Radiation image conversion panel and manufacturing method - Google Patents

Description

或いは、以下の様な液体層を用いることもできる。
【００９６】

又、本発明の低屈折率層として、空気、窒素、アルゴンなどの気体層や真空層など屈折率が実質的に１である層を用いると、鮮鋭性の低下を防止する効果が高く特に好ましい。
【００９７】
本発明の低屈折率層の厚さは０．０５μｍから３ｍｍまでが実用的である。
本発明の低屈折率層は、輝尽層と密着状態にあってもよいし、離れていてもよい。低屈折率層と輝尽層を密着させるためには、接着剤を用いるのが１つの方法であるが、その場合、接着剤の屈折率は輝尽層の屈折率または低屈折率層の屈折率に近いことが好ましい。
【００９８】
図５に、本発明の放射線画像変換パネルを用いた放射線像変換方法を概略的に示す。
【００９９】
即ち、図５において、２１は放射線発生装置、２２は被写体、２３は本発明に係わる放射線画像変換パネル、２４は（レーザ等の）輝尽励起光源、２５は該変換パネルにより放射された輝尽蛍光を検出する光電変換装置、２６は２５で検出された信号を画像として再生する装置、２７は再生された画像を表示する装置、２８は輝尽励起光と輝尽蛍光とを分離し、輝尽蛍光のみを透過させるフィルタである。尚、２５以降は２３からの光情報を何らかの形で画像として再生できるものであればよく、上記に限定されるものではない。
【０１００】
図５に示されるように、放射線発生装置２１からの放射線（Ｒ）は被写体２２を通して放射線画像変換パネル２３に入射する（ＲＩ）。この入射した放射線はパネル２３の輝尽層に吸収され、そのエネルギーが蓄積され、放射線透過像の蓄積像が形成される。
【０１０１】
次にこの蓄積像を輝尽励起光源２４からの輝尽励起光で励起して輝尽発光として放出せしめる。
【０１０２】
放射される輝尽発光の強弱は蓄積された放射線エネルギー量に比例するので、この光信号を例えば光電子倍増管等の光電変換装置２５で光電変換し、画像再生装置２６によって画像として再生し画像表示装置２７によって表示することにより、被写体の放射線透過像を観察することができる。
【０１０３】
【実施例】
以下実施例により本発明を説明するが本発明はこれにより限定されるものではない。
【０１０４】
実施例１
《輝尽性蛍光体プレートの作製》
１ｍｍ厚、面積４１０ｍｍ×４１０ｍｍの結晶化ガラス（日本電気ガラス社製）基板の表面に図１に示した気相堆積装置を用いて輝尽性蛍光体（ＣｓＢｒ：Ｅｕ）を有する輝尽性蛍光体層を形成した。
【０１０５】
尚、蒸着にあたっては、前記基板を前記気相堆積装置内に設置し、次いで、蛍光体原料（ＣｓＢｒ：Ｅｕ）をプレス成形し水冷したルツボにいれ蒸着源とした。
【０１０６】
その後、気相堆積装置内を排気口にポンプを接続して排気し、更にガス導入口から窒素を導入して（流量１０００ｓｃｃｍ（ｓｃｃｍ：ｓｔａｎｄａｒｄ ｃｃ／ｍｉｎ（１×１０^-6ｍ³／ｍｉｎ）））、装置内の真空度を６．６５×１０^-3Ｐａに維持した後、蒸着源を６５０℃に加熱し、ガラス基板の一方の面に、ＣｓＢｒ：０．０００１Ｅｕからなるアルカリハライド蛍光体を基板表面の法線方向から、基板と蒸発源の距離を６０ｃｍとして、基板と平行な方向に基板を搬送しながら蒸着を行なった。輝尽性蛍光体層の膜厚が４００μｍとなったところで蒸着を終了させ、蛍光体プレート１を作製した。
【０１０７】
また、蒸着の条件、即ち、装置内の真空度を、窒素ガスの導入量を変更して、６．６５×１０^-2Ｐａとした以外は同様に膜厚が４００μｍの輝尽性蛍光体層を有する基板（蛍光体プレート２）を、更に、器内の真空度を６．６５×１０^-1Ｐａとした以外は同様にして膜厚が４００μｍの輝尽性蛍光体層を有する基板（蛍光体プレート３）を作製した。
【０１０８】
また、比較例として、前記の気相堆積装置に代えて、図３の（ｂ）におけるようにガス導入口と排出口を結ぶ直線が基板端面から４０ｍｍ（図３（ｂ）におけるｘ＝４０ｍｍ）離れた位置に、それぞれガス導入口と排出口がある気相堆積装置をもちいた以外は、器内の真空度を６．６５×１０^-1Ｐａとし、同様にして、厚み４００μｍの輝尽性蛍光体層を形成した基板（蛍光体プレート４）を作製した。
【０１０９】
更に、比較例として蛍光体プレート４と同様に、但し、窒素ガスの導入量を減らし（導入を止め）、真空度を１．３３×１０^-4Ｐａとした以外は、同様にして蛍光体プレート５を作製した。
【０１１０】
この様にして作製した輝尽性蛍光体層をガラス基板上に有する蛍光体プレート１〜５を用いて、以下の試験を行い基板に対する付着性を評価した。
【０１１１】
（付着性の評価）
上記作製した各蛍光体プレート１〜５の蛍光体層塗設面に接着テープを張り付け、テープをはがしたときに蛍光体層が基板に付着した面積％を測定し、以下に示す基準により接着性の評価を行った。評価の結果を表１に示す。
【０１１２】
５：蛍光体層が基板に付着した面積が１００％
４：蛍光体層が基板に付着した面積が８０％以上１００％未満
３：蛍光体層が基板に付着した面積が６０％以上８０％未満
２：蛍光体層が基板に付着した面積が４０％以上６０％未満
１：蛍光体層が基板に付着した面積が４０％未満
この結果を表１に示した。
【０１１３】
【表１】

【０１１４】
窒素ガス導入口と排出口断面のそれぞれ中心を結んだ直線が、基板面に投影したときに、基板を通過するような位置に導入口と排出口が備えられた装置をもちいてガスを所定の量で導入した蛍光体プレート２、３が特に付着性に優れていることがわかる。また、導入口と排出口を結んだ直線が基板面にこれを投影したときに、基板上を通らない気相堆積装置（図３の（ｂ）で示される）をもちいて作製された蛍光体プレート４、或いは窒素ガスを導入しないで高真空下で気相堆積された蛍光体プレート５は基板と蛍光体層の付着性が十分でないことがわかる。
【０１１５】
次いで、上記プレート２，３および５について、作製後、直ちに作業室（絶対湿度１．３３×１０³Ｐａ）に移し、ガラス基板の上、輝尽性蛍光体層の周囲に、３００μｍの厚さの空気層が設けられるように厚さ７００μｍで幅５ｍｍのガラスのスペーサを配置しエポキシ系接着剤（スリーボンド社製）で接着する加工を行った。
【０１１６】
又、別途、保護層として用いる、以下に従って作製されたガラスを準備しておき、これを重ねてエポキシ系接着剤をもちいて直ちに封着し、放射線画像変換パネル試料２、３および５をそれぞれ作製した。
【０１１７】
ガラス製の保護層は以下のように作製した。
着色無しの透明ガラス（厚みが５５０μｍ、屈折率１．５２、輝尽励起光（半導体レーザ；６８０ｎｍ）における透過率が９８％）の透明ガラス表面に直接、以下に示す顔料分散塗布液を塗布してガラスの片面に輝尽励起光（半導体レーザ；６８０ｎｍ）における透過率がそれぞれ８５％となるように厚みを調整しバーコーターにて塗布し乾燥したもの。
【０１１８】
（顔料分散塗布液）
銅フタロシアニン １．０ｇ
ポリビニルブチラール １０００ｇ
メチルエチルケトン １００００ｇ
をサンドミル（ウイリー・エ・バッコーフェン社製ダイノーミルＫＤ−６０）を用いて６時間分散し塗布液を調製した。
【０１１９】
上記作製した各放射線画像変換パネルそれぞれについて、管電圧８０ｋＶｐのＸ線を蛍光体プレートの裏面側から照射した後、パネルをＨｅ−Ｎｅレーザー光（６３３ｎｍ）で操作して励起し、蛍光体層から放射される輝尽発光を受光器（分光感度Ｓ−５の光電子像倍管）で受光して、その強度を測定して、感度を評価したが、いずれの放射線画像変換パネルについても、本質的には同様の感度を有していることがわかった。
【０１２０】
【発明の効果】
本発明により、気相堆積法により形成された輝尽性蛍光体層と基板との付着性の向上した放射線画像変換パネル及びその製造方法を提供することができた。
【図面の簡単な説明】
【図１】本発明に係わる気相堆積装置の一例を示す図である。
【図２】基板を移動させながら気相堆積法により蛍光体層を形成するところを示す図である。
【図３】排気口とガス導入口そして基板の位置関係を上面からみた図である。
【図４】基板上に輝尽性蛍光体層を蒸着により形成する様子を示す図である。
【図５】本発明の放射線画像変換パネルの使用例を示す概略図である。
【符号の説明】
１ 基板
２ 蒸着源
３ ガス導入口
４ 排気口
１３ 輝尽性蛍光体柱状結晶
２１ 放射線発生装置
２２ 被写体
２３ 放射線画像変換パネル
２４ 輝尽励起光源
２５ 光電変換装置
２６ 画像再生装置
２７ 画像表示装置
２８ フィルタ
Ｖ 蒸気流
Ｇ ガス[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a radiation image conversion panel in which elongated photostimulable phosphor columnar crystals are formed on a substrate by vapor deposition, and a radiation image conversion panel obtained thereby.
[0002]
[Prior art]
In recent years, a method of imaging a radiation image by a radiation image conversion panel using a photostimulable phosphor has been used.
[0003]
The stimulable phosphor layer of the radiation image conversion panel used in this radiation image conversion method is required to have high radiation absorption rate and light conversion rate, good image graininess, and high sharpness. .
[0004]
Various adjustments have been made so far in order to improve sensitivity and image quality by adjusting a plurality of factors related to sensitivity and image quality. Among them, for example, formation as a means for improving the sharpness of a radiographic image Attempts have been made to improve sensitivity and sharpness by controlling the shape of the photostimulable phosphor.
[0005]
As one of these attempts, for example, a fine phosphor formed by depositing a photostimulable phosphor on a support (substrate) having a fine concavo-convex pattern as disclosed in, for example, Japanese Patent Laid-Open No. 61-142497. There is a method using a photostimulable phosphor layer composed of pseudo-columnar blocks.
[0006]
Further, as described in JP-A-61-142500, a crack between columnar blocks obtained by depositing a stimulable phosphor on a support having a fine pattern was further developed by applying a shock treatment. A method of using a radiation image conversion panel having a photostimulable phosphor layer, and further a surface of the photostimulable phosphor layer formed on the surface of a support as described in JP-A-62-39737. A method using a radiation image conversion panel in which a pseudo-columnar shape is formed by cracking from the side, and further, as described in JP-A-62-110200, a photostimulable phosphor layer having a cavity by vapor deposition on the upper surface of a support There has also been proposed a method in which a cavity is grown by heat treatment and a crack is formed after the formation.
[0007]
In JP-A-2-58000, radiation having a stimulable phosphor layer in which elongated columnar crystals having a certain inclination with respect to the normal direction of the support are formed on the support by vapor deposition. An image conversion panel has been proposed.
[0008]
In attempts to control the shape of these photostimulable phosphor layers, all of the photostimulable phosphor layers are made columnar to suppress the lateral diffusion of photostimulated excitation light (or photostimulated luminescence). Since it can reach the support surface while repeating reflection at the crack (columnar crystal) interface, it has a feature that the sharpness of an image by stimulated emission can be remarkably increased.
[0009]
In the radiation image conversion panel having the photostimulable phosphor layer formed by vapor phase growth (deposition), the relationship between the sensitivity and the sharpness is improved, but the pseudo-columnar or columnar photostimulable phosphor crystal is also used. In JP-A-1-131498, attempts have been made to further improve the image quality by suppressing reflection and refraction at the layer interface in the radiation image conversion panel by further combining a low refractive index layer with the phosphor layer comprising ing.
[0010]
However, since the phosphor layer composed of these columnar photostimulable phosphor crystals is formed with elongated columnar crystals on the substrate, the adhesion (adhesiveness) to the substrate may not be sufficient. It was easy to peel off and it was necessary to improve durability. No technology has so far been disclosed that focuses on the adhesion (adhesiveness) of such columnar photostimulable phosphor crystals to a substrate.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to obtain a method for manufacturing a radiation image conversion panel capable of forming an elongated columnar crystal having good adhesion to a substrate by a vapor deposition method on the substrate. Another object is to obtain a radiation image conversion panel having a high radiation absorption rate and light conversion rate.
[0012]
[Means for Solving the Problems]
The above object of the present invention is achieved by the following means.
[0013]
1. On a substrate in a vapor deposition apparatus having an exhaust port connected to a vacuum pump for maintaining a predetermined degree of vacuum in the apparatus and a gas inlet for introducing a predetermined amount of inert gas into the apparatus. A method of manufacturing a radiation image conversion panel in which a layer made of a photostimulable phosphor is formed with a film thickness of 50 μm or more by vapor deposition, wherein a substrate and an evaporation source are arranged to face each other, When a straight line connecting the center of the gas inlet port passes between the substrate and the evaporation source and a straight line connecting the center of the exhaust port and the center of the gas inlet port is projected onto the substrate surface, the straight line is always the substrate. A method for producing a radiation image conversion panel, wherein the exhaust port and the gas introduction port are arranged so as to pass through the vapor flow, and the vapor flow generated by heating the evaporation source intersects the gas flow.
[0014]
2. The degree of vacuum in the vapor deposition apparatus is 1.33 Pa to 1.33 × 10 ^-3 2. The method for producing a radiation image conversion panel as described in 1 above, wherein the temperature is between Pa.
[0015]
3. The photostimulable phosphor layer formed on the substrate contains the photostimulable phosphor represented by the general formula (1), and is produced by the method for producing a radiation image conversion panel described in 1 or 2 above. Radiation image conversion panel characterized by being made.
[0016]
4). M in the general formula (1) ¹ 4. The radiation image conversion panel as described in 3 above, wherein is at least one alkali metal selected from the group consisting of K, Rb and Cs.
[0017]
5). 5. The radiation image conversion panel as described in 3 or 4 above, wherein X in the general formula (1) is at least one halogen selected from the group consisting of Br and I.
[0018]
6). M in the general formula (1) ² 6. The radiation image conversion panel according to any one of 3 to 5, wherein is at least one divalent metal selected from the group consisting of Be, Mg, Ca, Sr and Ba.
[0019]
7). M in the general formula (1) ^Three In any one of the above items 3 to 6, characterized in that is at least one trivalent metal selected from the group consisting of Y, Ce, Sm, Eu, Al, La, Gd, Lu, Ga and In. The radiation image conversion panel described.
[0020]
8). The radiation image conversion panel according to any one of 3 to 7, wherein b in the general formula (1) is 0 ≦ b ≦ 0.01.
[0021]
9. The radiation image conversion according to any one of 3 to 8, wherein A in the general formula (1) is at least one metal selected from the group consisting of Eu, Cs, Sm, Tl, and Na. panel.
[0022]
10. The radiation image conversion panel according to any one of 3 to 9, wherein the stimulable phosphor has a columnar crystal.
[0023]
11. 11. The radiation image conversion panel as described in 10 above, wherein the columnar crystal has a stimulable phosphor represented by the general formula (2) as a main component.
[0024]
Hereinafter, the present invention will be described in detail.
The present invention relates to a vapor deposition apparatus having an exhaust port connected to a vacuum pump for maintaining a predetermined degree of vacuum in the apparatus and a gas inlet for introducing a predetermined amount of inert gas into the apparatus. A method of manufacturing a radiation image conversion panel in which a layer made of a photostimulable phosphor is formed on a substrate by vapor deposition with a film thickness of 50 μm or more, wherein the substrate and the evaporation source are arranged facing each other, and the exhaust The straight line connecting the center of the exhaust port and the center of the gas inlet port passes between the substrate and the evaporation source, and the straight line connecting the center of the exhaust port and the center of the gas inlet port is the substrate surface. A radiation image conversion panel manufacturing method, characterized in that the straight line always passes through the substrate when projected above, and the vapor flow generated by heating the evaporation source intersects the gas flow. is there.
[0025]
The predetermined degree of vacuum is 1.33 × 10 ^-3 The degree of vacuum is in the range of ˜1.33 Pa, and the degree of vacuum is preferably slightly lower than the degree of vacuum in which normal vacuum deposition, CVD, or the like is performed. In the present invention, a stimulable phosphor raw material vapor for forming a columnar crystal layer of a stimulable phosphor on a substrate (for example, glass or the like) in a vapor deposition apparatus while maintaining the above degree of vacuum. In contrast, a predetermined amount of an inert gas (such as nitrogen or a rare gas) is mixed so as to maintain the degree of vacuum, thereby forming a photostimulable phosphor layer made of columnar crystals on the substrate. The temperature of an inert gas such as nitrogen to be introduced is set to, for example, a temperature of 0 ° C. to 30 ° C., and these gas flows are crossed and mixed with the vapor flow of the photostimulable phosphor material generated by heating the vapor deposition source. By doing so, the vapor flow of the stimulable phosphor material is cooled, and a radiation image conversion panel with improved adhesion of the stimulable phosphor columnar crystal to the substrate (adhesiveness to the substrate) is obtained.
[0026]
In order to deposit the phosphor on the substrate by the vapor deposition method, the evaporation source is heated to generate a phosphor material vapor flow. Since the temperature of the vapor flow is high (the substrate temperature rises to a temperature such as 200 to 300 ° C. in response to the vapor flow), the phosphor particles deposited and adhered to the substrate in such a state are the stimulable phosphor. When the substrate is returned to room temperature after the formation of the layer, it is considered that the thermal expansion coefficient of the substrate (for example, glass) and the substance forming the phosphor are different and the contraction rate is different. It is considered that the adhesion (adhesiveness) with the substrate is reduced.
[0027]
In the present invention, the vapor flow generated by heating the stimulable phosphor material and the flow of an inert gas such as nitrogen introduced are crossed and brought into contact with each other, so that the vapor flow of the stimulable phosphor material is reduced. Since the temperature decreases, it is estimated that the adhesion between the substrate and the photostimulable phosphor layer is improved when this is deposited on the substrate and the substrate is returned to room temperature.
[0028]
Crossing the stimulable phosphor raw material vapor flow with the inert gas flow such as nitrogen to be introduced is sufficient to reduce the temperature of the vapor flow substantially as described above. The vapor flow is brought into contact with an inert gas flow. For this purpose, the vapor deposition apparatus has an exhaust port connected to a vacuum pump for maintaining the inside of the apparatus at a predetermined degree of vacuum and the apparatus. It is preferable to arrange the gas inlet for introducing a predetermined amount of inert gas at a position as shown in the figure below with respect to the substrate and the vapor deposition source facing the substrate.
[0029]
FIG. 1 shows that the vapor flow of the stimulable phosphor material that forms columnar crystals of the stimulable phosphor on the substrate, which is generated by heating the evaporation source, and the inert gas flow intersect each other. It is a figure which shows an example of the vapor deposition apparatus concerning this invention. (A) is a top view of a vapor deposition apparatus, (b) is a front view, (c) shows the side view.
[0030]
In FIG. 1, reference numeral 1 denotes a glass substrate on which a stimulable phosphor layer is deposited, and 2 denotes an evaporation source such as a basket (crucible) containing a stimulable phosphor material. V represents a vapor flow of the stimulable phosphor material generated by heating, and G represents a gas (for example, nitrogen gas) supplied from the gas supply port. Reference numeral 3 denotes a gas introduction port, and 4 denotes an exhaust port.
[0031]
In the vapor deposition method, a raw material to be deposited in a vapor phase is placed in a basket (crucible) as a vapor deposition source 2, a substrate 1 on which a stimulable phosphor is deposited is disposed so as to face this, and a vacuum pump is disposed at an exhaust port 4. Are connected and evacuated, while an inert gas such as nitrogen is introduced from the gas introduction port 3 in a predetermined amount, and a predetermined amount (for example, 1.33 Pa to 1.33 × 10 6) corresponding to the amount of gas introduced. ^-3 After making the degree of vacuum (about Pa), a basket or a crucible as an evaporation source is heated to generate a vapor flow V of the stimulable phosphor.
[0032]
In this vapor deposition apparatus, an exhaust port 4 connected to a vacuum pump for keeping the inside of the device at a predetermined degree of vacuum and a gas inlet 3 for introducing a predetermined amount of inert gas into the device are an exhaust port. 4 and the gas inlet 3 are each a space between a plane formed by the surface of the substrate and a plane including a vapor deposition source facing the straight line connecting the center of the cross section of the exhaust port 4 and the center of the cross section of the gas inlet 3. And when the straight line connecting the center of the cross section of the exhaust port 4 and the center of the cross section of the gas inlet port 3 is projected onto a plane including the substrate surface, the straight line always passes through the substrate. Thus, the vapor flow generated by heating the evaporation source can intersect and mix with the gas flow.
[0033]
In FIG. 1, m is a plane including the substrate surface, n is a plane including the vapor deposition source, and c is a straight line connecting the center of the cross section of the exhaust port 4 and the center of the cross section of the gas introduction port 3. A straight line c connecting the center of the cross section of the exhaust port 4 and the center of the cross section of the gas introduction port 3 is between the plane m including the substrate surface and the plane n including the vapor deposition source, and is a plane including the substrate. By setting the projected line so that it passes over the substrate when projected, the vapor flow generated by heating the evaporation source can intersect the gas flow. In the vapor phase deposition apparatus of FIG. 1, (b) when viewed from the front view, the straight line c is at a substantially intermediate position between the substrate surface and the surface including the vapor deposition source, and (a) projected from the top view. The line passes through approximately the center of the substrate.
[0034]
In the process of forming the photostimulable phosphor layer by vapor deposition, the phosphor layer is formed by vapor deposition while moving as indicated by an arrow (substrates 1 and 1 ') as shown in FIG. However, even at that time, the projection line c must always overlap (pass through the substrate) with the substrate.
[0035]
Even if the inert gas flow introduced is crossed and mixed with the heated stimulable phosphor vapor flow, the gas flow caused by the gas introduced from the gas inlet and exhausted from the outlet is Since the gas diffuses and expands in a lateral direction with respect to a line connecting the center of the cross section of the gas inlet and the center of the cross section of the exhaust outlet, the line c connecting the exhaust outlet and the inlet is moved to the substrate surface. 1 does not necessarily pass through the center of the substrate as in FIG. 1, and the gas inlet and the outlet may be arranged so that the projection line overlaps (passes through the substrate) with the substrate. . However, FIG. 3 is a view of the positional relationship between the exhaust port, the gas inlet port, and the substrate from the top surface. In order to ensure uniform deposition and adhesion of the stimulable phosphor on the substrate, the gas inlet port is used. The gas introduction port and the discharge port are arranged so that a line c connecting the center of the cross section and the center of the cross section of the exhaust port is intermediate between the substrate surface and the surface constituting the evaporation source, and FIG. As shown in (a), when expressed as a relationship between the substrate and the projection line, when the substrate is an L × L ′ square (the substrate is usually a square), when each side of the substrate is divided into three equal parts, It is preferable that the projection line pass through a central region excluding 1/3 on both sides of L and L ′. Further, it is more preferable to pass through a region close to the center, and it is preferable that the range is within the range of ± 1/10 × L (or L ′).
[0036]
FIG. 3B shows a case where the projection line deviates from the substrate surface. The effect of the present invention is lost as x increases.
[0037]
Therefore, even when vapor deposition is performed while moving the substrate, the projection line passes through the central region excluding 1/3 on both sides of L or L ′, and further through the region closer to the center. Therefore, it is preferable to increase the time for performing vapor deposition. In addition, when it is deviated from the center, it is possible to set the movement pattern so that the deviation is symmetrical (that is, the projection line passes through the central region as much as possible when time-averaged), and the uniform adhesion to the substrate It is preferable in securing the property.
[0038]
Even when the substrate is not necessarily a square, it is assumed that the substrate surrounds the substrate (one side of which is parallel to the line connecting the exhaust port and the gas inlet), the rectangle is regarded as a substrate, and a projected line is projected onto the substrate. The exhaust port and the gas introduction port are arranged so that the gas passes through.
[0039]
In addition, the exhaust port and the gas inlet port are usually circular in cross section, but even if they have a shape other than a circle, the center of the circle circumscribing the cross section is regarded as the center of the exhaust port and the gas inlet port. What is necessary is just to look at the projection line on the substrate surface of the line connecting
[0040]
Until now, in the method for producing a photostimulable phosphor, for example, an inert gas such as nitrogen gas has not been introduced, and a higher vacuum (for example, 1.333 × 10 6) than in the present invention has not been introduced. ^-Four However, the plate formed by these methods does not have sufficient adhesion of the phosphor layer to the substrate, and in particular, high CsBr. In the plate using the above, it was remarkable, but the above-mentioned N ₂ As the degree of vacuum in the vapor deposition apparatus used for the vapor deposition method under a lower vacuum that cools the stimulable phosphor vapor flow to form the phosphor layer by introducing the phosphor, etc., is 1.33 Pa. ~ 1.33 × 10 ^-3 The degree of vacuum in the apparatus is preferably such that the vapor flow of the photostimulable phosphor between the substrate and the evaporation source is measured at the passage portion. By using the vapor phase deposition apparatus according to the present invention, the adhesion of the phosphor layer to the substrate can be particularly improved in the CsBr plate which is a preferable stimulable phosphor.
[0041]
Examples of the stimulable phosphor used in the radiation image conversion panel of the present invention include, for example, BaSO described in JP-A-48-80487. _Four : A phosphor represented by Ax, MgSO described in JP-A-48-80488 _Four A phosphor represented by Ax, SrSO described in JP-A-48-80489 _Four : Phosphor represented by Ax, Na described in JP-A-51-29889 ₂ SO _Four , CaSO _Four And BaSO _Four A phosphor obtained by adding at least one of Mn, Dy and Tb to BeO, LiF, MgSO described in JP-A-52-30487 _Four And CaF ₂ And phosphors described in JP-A-53-39277 ₂ B _Four O ₇ : Phosphors such as Cu and Ag, Li described in JP-A-54-47883 ₂ O · (Be ₂ O ₂ ) X: phosphors such as Cu and Ag, SrS: Ce, Sm, SrS: Eu, Sm, La described in US Pat. No. 3,859,527 ₂ O ₂ Examples thereof include phosphors represented by S: Eu, Sm and (Zn, Cd) S: Mnx. Further, a ZnS: Cu, Pb phosphor described in JP-A-55-12142, the general formula of which is BaO.xAl. ₂ O _Three : The barium aluminate phosphor mentioned in Eu, and the general formula is M (II) O.xSiO ₂ : An alkaline earth metal silicate phosphor represented by A.
[0042]
Further, the general formula described in JP-A-55-12143 is represented by (Ba _1-xy Mg _x Ca _y ) F _x : Eu ²⁺ An alkaline earth fluorohalide phosphor represented by the formula: a phosphor represented by the general formula described in JP-A No. 55-12144: LnOX: xA, described in JP-A No. 55-12145 The general formula is (Ba _1-x M (II) _x ) F _x : A phosphor represented by yA, a phosphor represented by the general formula described in JP-A-55-84389, BaFX: xCe, yA, a formula represented by JP-A-55-160078 Is a rare earth element-activated divalent metal fluorohalide phosphor represented by M (II) FX · xA: yLn, fluorescence represented by the general formula ZnS: A, CdS: A, (Zn, Cd) S: A, X And any one of the following general formulas described in JP-A-59-38278
xM _Three (PO _Four ) ₂ ・ NX ₂ : YA
xM _Three (PO _Four ) ₂ : YA
A phosphor represented by any one of the following general formulas described in JP-A-59-155487:
nReX _Three ・ MAX ' ₂ : XEu
nReX _Three ・ MAX ' ₂ : XEu, ySm
And a bismuth-activated alkali halide phosphor represented by the general formula M (I) X: xBi described in JP-A No. 61-228400.
[0043]
However, alkali halide photostimulable phosphors represented by the following general formula (1) as described in JP-A Nos. 61-72087 and 2-58000 are particularly preferable.
[0044]
General formula (1)
M ¹ X ・ aM ² X ' ₂ ・ BM ^Three X ″ _Three : EA
Where M ¹ Is at least one alkali metal selected from Li, Na, K, Rb and Cs; ² Is at least one divalent metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu and Ni. ^Three Is at least one selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga and In. A trivalent metal, X, X ′ and X ″ are at least one halogen selected from the group consisting of F, Cl, Br and I, and A is Eu, Tb, In, Ga, Cs, Ce, Tm. , Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg, and at least one metal selected from the group consisting of a, b and c represents a numerical value in the range of 0 ≦ a <0.5, 0 ≦ b <0.5, and 0 <e ≦ 0.2, respectively.
[0045]
In these general formulas (1), M ¹ Is preferably selected from the group consisting of K, Rb and Cs, and X is preferably selected from the group consisting of Br and I.
[0046]
M ² Is preferably selected from the group consisting of Be, Mg, Ca, Sr and Ba; ^Three Is preferably selected from the group consisting of Y, Ce, Sm, Eu, Al, La, Gd, Lu, Ga and In. Further, b is preferably 0 ≦ b ≦ 0.01, and A is preferably selected from the group consisting of Eu, Cs, Sm, Tl and Na.
[0047]
These alkali halide photostimulable phosphors are formed on a substrate by vapor deposition, so that they have a certain inclination with respect to the normal direction of the substrate (of course, there is no inclination and the substrate surface is not inclined). It forms an elongated columnar crystal (although it may be vertical). By forming such columnar crystals, it is possible to suppress the diffusion of stimulated excitation light (or stimulated emission) in the lateral direction. Therefore, it is necessary to use these phosphors that the sharpness of the image by stimulated emission is good. It is a feature when there was. Among the alkali halide photostimulable phosphors, RbBr and CsBr phosphors are preferable because of high brightness and high image quality.
[0048]
In the present invention, a phosphor represented by the following general formula (2) is particularly preferable among them.
[0049]
General formula (2)
CsX: A
In the formula, X represents Br or I, and A represents Eu, In, Ga, or Ce.
[0050]
Among them, a CsBr phosphor is particularly preferable because it has a particularly high luminance and high image quality, and also has a high effect of improving adhesion (adhesion) with the substrate or the substrate by the production method of the present invention.
[0051]
The columnar crystals obtained by using these photostimulable phosphors that are preferable in the present invention, that is, the crystals growing in columnar form with a certain gap are described in JP-A-2-58000. Can be obtained by different methods.
[0052]
That is, a photostimulable phosphor layer composed of independent elongated columnar crystals can be obtained by supplying vapor of the stimulable phosphor or the raw material onto a substrate and performing vapor phase growth (deposition) such as vapor deposition.
[0053]
For example, by making the vapor flow of the photostimulable phosphor at the time of vapor deposition enter in the range of 0 to 5 degrees with respect to the direction perpendicular to the substrate, it is possible to obtain crystals that are substantially perpendicular to the substrate surface.
[0054]
In these cases, it is appropriate that the distance between the shortest part of the substrate and the crucible is set to approximately 10 cm to 60 cm in accordance with the average range of the stimulable phosphor.
[0055]
The stimulable phosphor as an evaporation source is uniformly dissolved or formed by pressing or hot pressing and charged in a crucible. At this time, it is preferable to perform a degassing treatment. The method for evaporating the photostimulable phosphor from the evaporation source is performed by scanning the electron beam emitted from the electron gun, but it can also be evaporated by other methods.
[0056]
The evaporation source is not necessarily a stimulable phosphor, and may be a mixture of a stimulable phosphor material.
[0057]
Moreover, what activator mixed the activator with respect to a base substance (basic substance) may be vapor-deposited, and after depositing only a base material, you may dope an activator afterwards. For example, when the base is CsBr, after depositing only CsBr, for example, In that is an activator may be doped. That is, since the crystals are independent, even if the film is thick, it can be sufficiently doped, and crystal growth hardly occurs, so the MTF does not decrease.
[0058]
Doping can be performed by thermal diffusion and ion implantation of a doping agent (activator) in the base layer of the formed phosphor.
[0059]
The layer thickness of the stimulable phosphor layer made of columnar crystals formed by these methods varies depending on the sensitivity of the intended radiation image conversion panel to radiation, the type of stimulable phosphor, etc., but from the range of 50 μm to 1000 μm. It is preferably selected, and more preferably selected from 50 μm to 800 μm.
[0060]
In order to improve the modulation transfer function (MTF) in the photostimulable phosphor layer composed of these columnar crystals, the size of the columnar crystals (breakdown of each columnar crystal when the columnar crystal is observed from a plane parallel to the substrate). The average value of the diameter of the area in terms of a circle, calculated from a microphotograph including at least 100 columnar crystals in the visual field) is preferably about 0.5 to 50 μm, more preferably 0.5 to 20 μm. is there. That is, when the columnar crystal is thinner than 0.5 μm, the excitation excitation light is scattered by the columnar crystal, so that the MTF is lowered. When the columnar crystal is 50 μm or more, the directivity of the excitation excitation light is also reduced. , MTF decreases.
[0061]
As a method for vapor phase growth (deposition) of the photostimulable phosphor, there are an evaporation method, a sputtering method, and a CVD method.
[0062]
In the vapor deposition method, after the substrate (support) is installed in the vapor deposition apparatus, the inside of the apparatus is evacuated, and at the same time, an inert gas such as nitrogen is introduced from the introduction port to 1.333 Pa to 1.33 × 10 ^-3 A vacuum of about Pa is applied, and then at least one of the stimulable phosphors is heated and evaporated by a resistance heating method, an electron beam method, or the like to deposit the stimulable phosphors on the surface of the support to a desired thickness. As a result, a photostimulable phosphor layer containing no binder is formed, but it is also possible to form the photostimulable phosphor layer in a plurality of times in the vapor deposition step. In the vapor deposition step, vapor deposition can be performed using a plurality of resistance heaters or electron beams. In the vapor deposition method, the stimulable phosphor material is deposited using a plurality of resistance heaters or electron beams, and the desired stimulable phosphor layer is synthesized on the support at the same time. It is also possible to form. Further, in the vapor deposition method, the substrate (support) may be cooled or heated as necessary during vapor deposition. Moreover, you may heat-process a photostimulable phosphor layer after completion | finish of vapor deposition.
[0063]
In the sputtering method, after the substrate is placed in the sputtering apparatus, the inside of the apparatus is once evacuated to a vacuum, and then an inert gas such as Ar or Ne is introduced into the apparatus as a sputtering gas. 1.33 Pa to 1.33 × 10 ^-3 The gas pressure is about Pa. Next, the stimulable phosphor is deposited to a desired thickness on the substrate surface by sputtering using the stimulable phosphor as a target. In this sputtering process, it is possible to form the photostimulable phosphor layer in a plurality of times in the same manner as the vapor deposition method, and by using each of them simultaneously or sequentially, the target is sputtered to produce the photostimulable phosphor layer. It is also possible to form In addition, in the sputtering method, it is possible to form a desired stimulable phosphor layer on a substrate by using a plurality of photostimulable phosphor materials as a target and sputtering them simultaneously or sequentially. O if necessary ₂ , H ₂ Reactive sputtering may be performed by introducing a gas such as. Furthermore, in the sputtering method, the substrate may be cooled or heated as necessary during sputtering. Alternatively, the photostimulable phosphor layer may be heat-treated after the end of sputtering.
[0064]
The CVD method does not contain a binder on the substrate by decomposing the target stimulable phosphor or organometallic compound containing the stimulable phosphor raw material with heat, high-frequency power, or other energy. In any case, the phosphor layer can be vapor-phase grown into independent elongated columnar crystals with a specific inclination with respect to the normal direction of the substrate.
[0065]
These columnar crystals are obtained by the method described in JP-A-2-58000 as described above, that is, a method in which vapor of stimulable phosphor or the raw material is supplied onto a substrate and vapor phase growth (deposition) such as vapor deposition is performed. Can be obtained at
[0066]
FIG. 4 is a view showing a state in which a photostimulable phosphor layer is formed on the substrate 1 by vapor deposition. 13 schematically represents the photostimulable phosphor columnar crystal formed. Assuming that the incident angle of the vapor flow V of the stimulable phosphor with respect to the normal direction (P) of the substrate surface is θ2, the angle of the formed columnar crystal with respect to the normal direction (P) of the substrate surface is represented by θ1. . A columnar crystal is formed at a constant angle θ1 depending on the incident angle θ2. The angle of the formed columnar crystals varies depending on the stimulable phosphor material. For example, among the alkali halide phosphors, in the case of the CsBr phosphor particularly preferable in the present invention, for example, the stimuli during vapor deposition are used. By making the vapor flow of the fluorescent phosphor incident in the range of 0 to 5 degrees with respect to the direction perpendicular to the substrate (that is, θ2 is 0 to 5 degrees), it is substantially perpendicular to the substrate surface (θ1 is approximately 0 degrees). Can be obtained.
[0067]
Since the photostimulable phosphor layer formed on the substrate in this manner does not contain a binder, it has excellent directivity, high directivity of stimulated excitation light and stimulated emission, and The layer thickness can be made thicker than that of a radiation image conversion panel having a dispersive photostimulable phosphor layer in which a fluorescent material is dispersed in a binder. Furthermore, the sharpness of the image is improved by reducing the scattering of the stimulating light in the stimulable phosphor layer.
[0068]
In addition, the gap between the columnar crystals may be filled with a filler or the like, which reinforces the photostimulable phosphor layer. Further, a substance having a high light absorption rate, a substance having a high light reflectance, or the like may be filled. As a result, the above-mentioned reinforcing effect can be provided, and the light diffusion in the lateral direction of the stimulated excitation light incident on the stimulable phosphor layer can be almost completely prevented.
[0069]
The substance having high light reflectance means a material having high reflectance with respect to stimulating excitation light (500 to 900 nm, particularly 600 to 800 nm), such as white pigment and green to red, such as aluminum, magnesium, silver, indium and other metals. Area colorants can be used.
[0070]
White pigments can also reflect stimulated emission. TiO as white pigment ₂ (Anatase type, rutile type), MgO, PbCO _Three ・ Pb (OH) ₂ , BaSO _Four , Al ₂ O _Three , M (II) FX (where M (II) is at least one of Ba, Sr and Ca, and X is at least one of Cl and Br), CaCO _Three , ZnO, Sb ₂ O _Three , SiO ₂ , ZrO ₂ , Lithopone (BaSO _Four ZnS), magnesium silicate, basic lead silicate, basic lead phosphate, aluminum silicate, etc. Since these white pigments have a strong hiding power and a high refractive index, they can easily scatter scattered light by reflecting or refracting light, and can significantly improve the sensitivity of the resulting radiation image conversion panel.
[0071]
Moreover, as a substance having a high light absorption rate, for example, carbon, chromium oxide, nickel oxide, iron oxide and the like and a blue color material are used. Of these, carbon also absorbs stimulated luminescence.
[0072]
The color material may be either an organic or inorganic color material. Examples of organic colorants include Zavon First Blue 3G (Hoechst), Estrol Brill Blue N-3RL (Sumitomo Chemical), D & C Blue No. 1 (made by National Aniline), Spirit Blue (made by Hodogaya Chemical), Oil Blue No. 1 603 (made by Orient), Kitten Blue A (made by Ciba Geigy), Eisen Katyron Blue GLH (made by Hodogaya Chemical), Lake Blue AFH (made by Kyowa Sangyo), Primocyanin 6GX (made by Inabata Sangyo), Brill Acid Green 6BH (Hodogaya) Chemical Blue), Cyan Blue BNRCS (Toyo Ink), Lionoyl Blue SL (Toyo Ink), etc. are used. The color index No. 24411, 23160, 74180, 74200, 22800, 23154, 23155, 24401, 14830, 15050, 15760, 15707, 17941, 74220, 13425, 13361, 13420, 11836, 74140, 74380, 74350, 74460, etc. There are also materials. Inorganic color materials include ultramarine, cobalt blue, cerulean blue, chromium oxide, TiO ₂ -ZnO-Co-NiO pigments.
[0073]
The substrate (support) used in the radiation image conversion panel of the present invention is preferably a substrate having low moisture permeability, and various types of glass, polymer materials, metals, etc. are used. For example, quartz, borosilicate glass, chemical Plate glass such as mechanically tempered glass, plastic film such as cellulose acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film, triacetate film, polycarbonate film, metal sheet such as aluminum sheet, iron sheet, copper sheet or the like A metal sheet having a metal oxide coating layer is preferred. The surface of these supports may be a smooth surface, or may be a matte surface for the purpose of improving the adhesion to the stimulable phosphor.
[0074]
In the present invention, in order to improve the adhesion between the substrate and the stimulable phosphor, an adhesive layer may be provided in advance on the surface of the substrate as necessary.
[0075]
Although the thickness of these substrates varies depending on the material of the substrate used, it is generally 80 μm to 2000 μm, and more preferably 80 μm to 1000 μm from the viewpoint of handling.
[0076]
Among alkali halide photostimulable phosphors, RbBr and CsBr phosphors are preferred because of their high brightness and high image quality, but they are vulnerable to moisture, so they can be sealed using a protective layer, spacer, or sealant. It is preferable to do.
[0077]
As a protective layer, what can be formed in a sheet form with good translucency can be used. Examples thereof include plate glass such as quartz, borosilicate glass and chemically tempered glass, and organic polymers such as PET, OPP and polyvinyl chloride.
[0078]
The protective layer of the present invention may be a single layer, may be a multilayer, or may be composed of two or more types of layers having different materials. For example, a film in which two or more polymer films are combined can be used. Examples of a method for producing such a composite polymer film include dry lamination, extrusion lamination, and coextrusion coating lamination. The combination of two or more protective layers is not limited to organic polymers, and includes plate glasses or plate glasses and organic polymers. For example, as a method of combining the plate glass and the polymer layer, there is a method in which a protective layer coating solution is directly applied on the plate glass, or a method in which a separately formed polymer protective layer is adhered on the plate glass. . Two or more protective layers may be in close contact with each other or may be separated from each other.
[0079]
The thickness of the protective layer of the present invention is practically 10 μm to 3 mm. In order to obtain good moisture resistance and impact resistance, the thickness of the protective layer is preferably 100 μm or more, and particularly when a protective layer of 500 μm or more is provided, a conversion panel excellent in durability and durability can be obtained. Even more preferred.
[0080]
Moreover, when plate glass is used as the protective layer, it is particularly preferable because it is extremely excellent in moisture resistance.
[0081]
The protective layer desirably exhibits high transmittance in a wide wavelength range in order to efficiently transmit stimulated excitation light and stimulated emission, and the transmittance is 60% or more, preferably 80% or more. For example, quartz glass, borosilicate glass, and the like can be given. Borosilicate glass exhibits a transmittance of 80% or more in the wavelength range of 330 nm to 2.6 μm, and quartz glass exhibits a high transmittance even at a shorter wavelength.
[0082]
Moreover, MgF is formed on the surface of the protective layer. ₂ It is preferable to provide an antireflective layer such as that because it effectively transmits the stimulated excitation light and the stimulable light emission and reduces the reduction in sharpness. The refractive index of the protective layer is not particularly specified, but many practically used materials are between 1.4 and 2.0.
[0083]
In order to improve the sharpness, the glass may be colored by containing a colorant such as lead phosphate to absorb the stimulated excitation light.
[0084]
For that purpose, a film colored with a coloring material (pigment or coloring matter) that absorbs stimulating excitation light is laminated on the glass, or a layer containing a coloring matter or pigment is applied on either side of the glass,
There is also a method in which the glass itself contains a dispersed pigment or colorant as a coloring material.
[0085]
As a method for producing a colored film, there is a method of forming a layer containing a coloring material (pigment or dye) on the surface of a plastic film or a plastic film kneaded with a coloring material, and bonding the colored plastic film. Colored glass can be obtained by a method of uniformly bonding to the glass surface using an agent or the like.
[0086]
Alternatively, a pigment or dye dispersed or dissolved in a binder (water glass, organic polymer such as polyvinyl butyral, etc.) having good adhesiveness with glass may be directly applied to the glass.
[0087]
The coloring material that can absorb the excitation light used in these protective layers may be either an organic or inorganic coloring material. Examples of the organic coloring material include Zavon Fast Blue 3G (manufactured by Hoechst), Estrol Brill Blue N- 3RL (manufactured by Sumitomo Chemical), D & C Blue No. 1 (made by National Aniline), Spirit Blue (made by Hodogaya Chemical), Oil Blue No. 1 603 (made by Orient), Kitten Blue A (made by Ciba Geigy), Eisen Katyron Blue GLH (made by Hodogaya Chemical), Lake Blue AFH (made by Kyowa Sangyo), Primocyanin 6GX (made by Inabata Sangyo), Brill Acid Green 6BH (Hodogaya) Chemical Blue), Cyan Blue BNRCS (Toyo Ink), Lionoyl Blue SL (Toyo Ink), etc. are used. The color index No. 24411, 23160, 74180, 74200, 22800, 23154, 23155, 24401, 14830, 15050, 15760, 15707, 17941, 74220, 13425, 13361, 13420, 11836, 74140, 74380, 74350, 74460, etc. Or a pigment is also mentioned. In particular, metal phthalocyanine pigments are preferred. Inorganic color materials include ultramarine, cobalt blue, cerulean blue, chromium oxide, TiO ₂ -ZnO-Co-NiO pigments.
[0088]
The spacer is not particularly limited as long as it can hold the photostimulable phosphor layer in a state of being cut off from the external atmosphere. Glass, ceramics, metal, plastic, etc. have a moisture permeability of 30 g / m. ² A material that is 24 hr or less is preferred.
[0089]
The thickness of the spacer is preferably equal to or greater than the thickness of the photostimulable phosphor layer, and the width is determined mainly in relation to the moisture resistance (moisture permeability) of the contact portion between the spacer and the substrate and the protective layer. 1-30 mm is preferable. If the width of the spacer is too small, it is not preferable from the viewpoint of the stability, strength and moisture resistance of the spacer. On the other hand, if the size is too large, the radiation image conversion panel becomes unnecessarily large, which is not preferable.
[0090]
In addition, the water vapor transmission rate at the contact portion between the spacer, the substrate and the protective layer is also 30 g / m. ² -It is preferable that it is 24 hours or less.
[0091]
In the present invention, the sealing agent is a material for directly adhering the spacer to the substrate and the protective layer, or directly adhering the substrate and the protective layer, and an adhesive is used, and this adhesive is preferably moisture-proof. Epoxy adhesives are particularly suitable because of their low moisture permeability.
[0092]
For the purpose of improving the adhesion of the spacer and the substrate or the adhesion portion between the spacer and the protective layer, an undercoat layer is provided on the adhesive surface between the spacer, the substrate and the protective layer, or a roughening treatment is performed. You can also.
[0093]
Further, it is possible to adhere and seal the substrate (support) and the protective layer with only the above-mentioned sealing agent without a spacer.
[0094]
In the present invention, a low refractive index layer may be provided. The low refractive index layer is made of a material having a refractive index lower than that of the protective layer, and the presence of this layer can reduce the reduction in sharpness even if the protective layer is thickened. For example, the following materials can be used and are preferably used in the state of a thin film formed by vapor deposition such as vapor deposition.
[0095]

Alternatively, the following liquid layer can be used.
[0096]

In addition, when a layer having a refractive index of substantially 1 such as a gas layer such as air, nitrogen or argon or a vacuum layer is used as the low refractive index layer of the present invention, the effect of preventing sharpness deterioration is particularly high. .
[0097]
The thickness of the low refractive index layer of the present invention is practically from 0.05 μm to 3 mm.
The low refractive index layer of the present invention may be in close contact with the photostimulable layer or may be separated. In order to adhere the low refractive index layer and the stimulating layer, one method is to use an adhesive. In that case, the refractive index of the adhesive is the refractive index of the stimulating layer or the refractive index of the low refractive index layer. It is preferable to be close to the rate.
[0098]
FIG. 5 schematically shows a radiation image conversion method using the radiation image conversion panel of the present invention.
[0099]
That is, in FIG. 5, 21 is a radiation generating device, 22 is a subject, 23 is a radiation image conversion panel according to the present invention, 24 is a stimulating excitation light source (such as a laser), and 25 is a stimulating light emitted by the converting panel. A photoelectric conversion device that detects fluorescence, 26 is a device that reproduces the signal detected in 25 as an image, 27 is a device that displays the reproduced image, and 28 is a device that separates stimulated excitation light and stimulated fluorescence. This is a filter that transmits only exhaust fluorescent light. It should be noted that anything after 25 can be used as long as the optical information from 23 can be reproduced as an image in some form, and is not limited to the above.
[0100]
As shown in FIG. 5, the radiation (R) from the radiation generator 21 enters the radiation image conversion panel 23 through the subject 22 (RI). The incident radiation is absorbed by the stimulating layer of the panel 23, the energy is accumulated, and an accumulated image of a radiation transmission image is formed.
[0101]
Next, this accumulated image is excited with stimulated excitation light from the stimulated excitation light source 24 and emitted as stimulated emission.
[0102]
Since the intensity of the photostimulated luminescence emitted is proportional to the amount of accumulated radiation energy, this optical signal is photoelectrically converted by a photoelectric conversion device 25 such as a photomultiplier tube, and reproduced as an image by an image reproduction device 26 to display an image. By displaying on the apparatus 27, a radiation transmission image of the subject can be observed.
[0103]
【Example】
EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto.
[0104]
Example 1
<Production of photostimulable phosphor plate>
A stimulable phosphor having a stimulable phosphor (CsBr: Eu) on the surface of a crystallized glass (manufactured by Nippon Electric Glass Co., Ltd.) substrate having a thickness of 1 mm and an area of 410 mm × 410 mm using the vapor deposition apparatus shown in FIG. A body layer was formed.
[0105]
In vapor deposition, the substrate was placed in the vapor deposition apparatus, and then a phosphor raw material (CsBr: Eu) was press-molded and placed in a water-cooled crucible to form a vapor deposition source.
[0106]
Thereafter, the vapor deposition apparatus is evacuated by connecting a pump to the exhaust port, and nitrogen is further introduced from the gas inlet (flow rate 1000 sccm (sccm: standard cc / min (1 × 10 6 ^-6 m ^Three / Min))), the degree of vacuum in the apparatus is 6.65 × 10 ^-3 After maintaining at Pa, the vapor deposition source is heated to 650 ° C., and the alkali halide phosphor made of CsBr: 0.0001Eu is applied to one surface of the glass substrate from the normal direction of the substrate surface, and the distance between the substrate and the evaporation source is set. The deposition was performed while the substrate was transported in a direction parallel to the substrate at 60 cm. When the thickness of the photostimulable phosphor layer reached 400 μm, the vapor deposition was terminated, and the phosphor plate 1 was produced.
[0107]
Further, the deposition conditions, that is, the degree of vacuum in the apparatus is changed to 6.65 × 10 6 by changing the amount of nitrogen gas introduced. ^-2 Except for Pa, a substrate (phosphor plate 2) having a stimulable phosphor layer with a film thickness of 400 μm was used, and the degree of vacuum in the vessel was further 6.65 × 10 6. ^-1 A substrate (phosphor plate 3) having a photostimulable phosphor layer with a film thickness of 400 μm was prepared in the same manner except for Pa.
[0108]
As a comparative example, instead of the vapor deposition apparatus, a straight line connecting the gas inlet and outlet is 40 mm from the substrate end face as shown in FIG. 3B (x = 40 mm in FIG. 3B). The degree of vacuum in the chamber is 6.65 × 10, except that a vapor deposition apparatus having gas inlets and outlets at separate positions is used. ^-1 In the same manner, a substrate (phosphor plate 4) on which a stimulable phosphor layer having a thickness of 400 μm was formed was prepared.
[0109]
Further, as a comparative example, similar to the phosphor plate 4, except that the amount of nitrogen gas introduced is reduced (introduction is stopped) and the degree of vacuum is 1.33 × 10 ^-Four A phosphor plate 5 was produced in the same manner except for Pa.
[0110]
Using the phosphor plates 1 to 5 having the photostimulable phosphor layer thus produced on the glass substrate, the following test was conducted to evaluate the adhesion to the substrate.
[0111]
(Evaluation of adhesion)
Adhesive tape is affixed to the phosphor layer coating surface of each of the phosphor plates 1 to 5, and the area% of the phosphor layer adhering to the substrate when the tape is peeled off is measured and adhered according to the criteria shown below. Sexuality was evaluated. The evaluation results are shown in Table 1.
[0112]
5: Area where the phosphor layer adheres to the substrate is 100%
4: The area where the phosphor layer adheres to the substrate is 80% or more and less than 100%
3: The area where the phosphor layer adheres to the substrate is 60% or more and less than 80%.
2: The area where the phosphor layer adheres to the substrate is 40% or more and less than 60%
1: Less than 40% of the area where the phosphor layer adheres to the substrate
The results are shown in Table 1.
[0113]
[Table 1]

[0114]
When a straight line connecting the centers of the cross sections of the nitrogen gas inlet and outlet is projected onto the substrate surface, the gas is passed through a predetermined amount using an apparatus provided with the inlet and outlet at a position that passes through the substrate. It can be seen that the phosphor plates 2 and 3 introduced in an amount are particularly excellent in adhesion. In addition, a phosphor manufactured using a vapor deposition apparatus (shown in FIG. 3B) that does not pass over the substrate when a straight line connecting the inlet and the outlet is projected onto the substrate surface. It can be seen that the plate 4 or the phosphor plate 5 vapor-deposited under high vacuum without introducing nitrogen gas does not have sufficient adhesion between the substrate and the phosphor layer.
[0115]
Next, immediately after the production of the plates 2, 3 and 5, the working chamber (absolute humidity 1.33 × 10 ^Three And a glass spacer having a thickness of 700 μm and a width of 5 mm so that an air layer having a thickness of 300 μm is provided around the photostimulable phosphor layer on the glass substrate, and an epoxy adhesive ( Adhesion processing was performed using a product manufactured by Three Bond Co., Ltd.
[0116]
Separately, a glass prepared as follows, which is used as a protective layer, is prepared, and this is overlaid and immediately sealed with an epoxy adhesive to produce radiation image conversion panel samples 2, 3 and 5, respectively. did.
[0117]
A glass protective layer was prepared as follows.
Apply the following pigment dispersion coating solution directly to the transparent glass surface of uncolored transparent glass (thickness: 550 μm, refractive index: 1.52, transmittance of excited excitation light (semiconductor laser: 680 nm): 98%). Then, the thickness is adjusted on one side of the glass so that the transmittance with respect to stimulating excitation light (semiconductor laser; 680 nm) is 85%, dried by applying with a bar coater.
[0118]
(Pigment dispersion coating solution)
Copper phthalocyanine 1.0g
Polyvinyl butyral 1000g
Methyl ethyl ketone 10000g
Was dispersed for 6 hours using a sand mill (Dynomill KD-60 manufactured by Willy et Bacofen) to prepare a coating solution.
[0119]
For each of the radiographic image conversion panels produced above, after irradiating X-rays with a tube voltage of 80 kVp from the back side of the phosphor plate, the panel was excited by operating with He-Ne laser light (633 nm), and from the phosphor layer The stimulated luminescence emitted was received by a photoreceiver (photoelectron image multiplier with spectral sensitivity S-5), the intensity was measured, and the sensitivity was evaluated. Was found to have similar sensitivity.
[0120]
【The invention's effect】
According to the present invention, it is possible to provide a radiation image conversion panel having improved adhesion between a photostimulable phosphor layer formed by a vapor deposition method and a substrate, and a method for manufacturing the same.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a vapor deposition apparatus according to the present invention.
FIG. 2 is a view showing a state where a phosphor layer is formed by a vapor deposition method while moving a substrate.
FIG. 3 is a view of the positional relationship between an exhaust port, a gas introduction port, and a substrate as viewed from above.
FIG. 4 is a view showing a state in which a photostimulable phosphor layer is formed on a substrate by vapor deposition.
FIG. 5 is a schematic view showing an example of use of the radiation image conversion panel of the present invention.
[Explanation of symbols]
1 Substrate
2 Deposition source
3 Gas inlet
4 Exhaust port
13 Stimulable phosphor columnar crystals
21 Radiation generator
22 Subject
23 Radiation image conversion panel
24 Excited light source
25 Photoelectric conversion device
26 Image playback device
27 Image display device
28 Filter
V Steam flow
G gas

Claims (11)

On a substrate in a vapor deposition apparatus having an exhaust port connected to a vacuum pump for maintaining a predetermined degree of vacuum in the apparatus and a gas inlet for introducing a predetermined amount of inert gas into the apparatus. A method of manufacturing a radiation image conversion panel in which a layer made of a photostimulable phosphor is formed with a film thickness of 50 μm or more by vapor deposition, wherein a substrate and an evaporation source are arranged to face each other, When a straight line connecting the center of the gas inlet port passes between the substrate and the evaporation source and a straight line connecting the center of the exhaust port and the center of the gas inlet port is projected onto the substrate surface, the straight line is always the substrate. A method for producing a radiation image conversion panel, wherein the exhaust port and the gas introduction port are arranged so as to pass through the vapor flow, and the vapor flow generated by heating the evaporation source intersects the gas flow. 2. The method of manufacturing a radiation image conversion panel according to claim 1, wherein a degree of vacuum in the vapor deposition apparatus is between 1.33 Pa and 1.33 × 10 ⁻³ Pa. ³ . The stimulable phosphor layer formed on the substrate contains a stimulable phosphor represented by the following general formula (1), and the method for producing a radiation image conversion panel according to claim 1 or 2. A radiation image conversion panel manufactured.
General formula (1)
M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : eA
[Wherein M ¹ is at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs, and M ² is Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu and At least one divalent metal selected from the group consisting of Ni, and M ³ is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, And at least one trivalent metal selected from the group consisting of Yb, Lu, Al, Ga and In, and X, X ′ and X ″ are at least one selected from the group consisting of F, Cl, Br and I. Halogen, A is composed of Eu, Tb, In, Ga, Cs, Ce, Tm, Dy, Pr, Ho, Nd, Yb, ErGd, Lu, Sm, Y, Tl, Na, Ag, Cu, and Mg At least one selected from the group A genus, also, a, b, e each represent a number between 0 ≦ a <0.5,0 ≦ b <0.5,0 <e ≦ 0.2.] The radiation image conversion panel according to claim 3, wherein M ¹ in the general formula (1) is at least one alkali metal selected from the group consisting of K, Rb, and Cs. 5. The radiation image conversion panel according to claim 3, wherein X in the general formula (1) is at least one halogen selected from the group consisting of Br and I. The M ² in the general formula (1) is at least one divalent metal selected from the group consisting of Be, Mg, Ca, Sr, and Ba. Radiation image conversion panel. The M ³ in the general formula (1) is at least one trivalent metal selected from the group consisting of Y, Ce, Sm, Eu, Al, La, Gd, Lu, Ga, and In. The radiation image conversion panel of any one of 3-6. The radiation image conversion panel according to claim 3, wherein b in the general formula (1) satisfies 0 ≦ b ≦ 0.01. The radiation image according to any one of claims 3 to 8, wherein A in the general formula (1) is at least one metal selected from the group consisting of Eu, Cs, Sm, Tl, and Na. Conversion panel. 10. The radiation image conversion panel according to claim 3, wherein the photostimulable phosphor has a columnar crystal. The radiation image conversion panel according to claim 10, wherein the columnar crystal has a stimulable phosphor represented by the following general formula (2) as a main component.
General formula (2)
CsX; A
[Wherein, X represents Br or I, and A represents Eu, In, Ga, or Ce. ]

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