JP2006064436A - Radiographic image conversion panel, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiographic image conversion panel excellent in both an adhesive property and high image quality (brightness), in particular, in CsBr stimulable phosphor, and a manufacturing method therefor. <P>SOLUTION: In this radiographic image conversion panel with a stimulable phosphor layer having CsBr:Eu stimulable phosphor formed on a support by a vapor deposition method (vapor phase method), layers of low luminous intensity and layers of high luminous intensity are layered alternately when a cross section of the stimulable phosphor layer is excited from a support side toward a phosphor layer surface side by an excitation light source. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radiation image stimulating conversion panel and a manufacturing method thereof.

  In recent years, a method of imaging a radiation image by a radiation image conversion panel using a stimulable phosphor has been used.

  This uses, for example, a radiation image conversion panel in which a photostimulable phosphor layer is formed on a support as disclosed in US Pat. No. 3,859,527 and JP-A-55-12144. It is. A radiation image (accumulated image) is formed by applying radiation transmitted through the subject to the stimulable phosphor layer of the radiation image conversion panel and storing radiation energy corresponding to the radiation transmittance of each part of the subject in the stimulable phosphor layer. By forming and scanning this stimulable phosphor layer with stimulating excitation light (laser light is used), the radiation energy accumulated in each part is emitted and converted into light, and the intensity of this light is read. Get an image. This image may be reproduced on various displays such as a CRT, or may be reproduced as a hard copy.

  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. .

  Usually, to increase the radiation sensitivity, it is necessary to increase the thickness of the photostimulable phosphor layer. However, if the thickness is too large, light emission is caused by scattering of photostimulated luminescence between photostimulable phosphor particles. There is a phenomenon that does not come out to the outside, there is a limit.

  The sharpness improves as the stimulable phosphor layer is made thinner. However, if it is too thin, the phenomenon of sensitivity increases.

  As for the graininess, the image graininess is determined by the local fluctuation of the radiation quantum number (quantum motor) or the structural disorder of the stimulable phosphor layer of the radiation image conversion panel (structure motor). When the thickness of the stimulable phosphor layer is reduced, the radiation quantum number absorbed in the stimulable phosphor layer decreases and the mottle increases, or the structural disturbance becomes obvious and the structure mottle increases. Decrease. Therefore, in order to improve the graininess of the image, the stimulable phosphor layer needs to be thick.

  As described above, the image quality and sensitivity of the radiation image conversion method using the radiation image conversion panel are determined from various factors. In order to improve the sensitivity and image quality by adjusting a plurality of factors related to sensitivity and image quality, various studies have been conducted so far.

  Among them, as means for improving the sharpness of a radiographic image, for example, an attempt has been made to improve the sensitivity and sharpness by controlling the shape of the stimulable phosphor to be formed.

  As one of these attempts, for example, a fine pseudo-columnar block formed by depositing a photostimulable phosphor on a support having a fine concavo-convex pattern, as performed in, for example, JP-A No. 61-142497 There is a method using a photostimulable phosphor layer made of

  Further, as described in JP-A-61-142500, the cracks between the columnar blocks obtained by depositing the photostimulable phosphor on the support having a fine pattern were 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 of 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.

  In addition, a radiation image conversion panel having a photostimulable 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 is proposed.

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. (For example, see Patent Document 1)
Recently, a radiation image conversion panel using a stimulable phosphor obtained by activating Eu with an alkali halide such as CsBr as a base has been proposed. In particular, high X-rays that have not been obtained by using Eu as an activator have been proposed. It became possible to derive the conversion efficiency.

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, and film formation It was easy to peel off later, and improvement in durability was demanded. In particular, in the case of CsBr photostimulable phosphors, there is a need for a radiation image conversion panel having a CsBr photostimulable phosphor that is difficult to achieve both adhesion and image quality characteristics (brightness) but has both adhesion properties and image quality characteristics. ing.
JP-A-2-58000

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a radiation image conversion panel excellent in both adhesion and image quality characteristics (luminance) particularly in a CsBr photostimulable phosphor and a method for producing the same. is there.

  The above object of the present invention is achieved by the following configurations.

(Claim 1)
In a radiation image conversion panel in which a photostimulable phosphor layer having a CsBr: Eu photostimulable phosphor is formed on a support by a vapor deposition method (vapor phase method), a cross section of the photostimulable phosphor layer is shown. A radiation image conversion panel, wherein a layer having a low emission intensity and a layer having a high emission intensity are alternately laminated when excited from the support side to the phosphor layer surface side by an excitation light source.

(Claim 2)
2. When the radiation image conversion panel according to claim 1 is manufactured using a vapor deposition apparatus having a plurality of evaporation sources and a plurality of shutters corresponding to the plurality of evaporation sources in a vacuum vessel, evaporation from the plurality of evaporation sources. A method of manufacturing a ray image conversion panel characterized in that the steps are alternately performed and the intervals between the evaporations of the plurality of evaporation sources are made discontinuous by opening and closing the shutter.

  The radiation image conversion panel and the method for producing the same according to the present invention have excellent effects particularly in adhesion and image quality characteristics (luminance) in a CsBr photostimulable phosphor.

  The present invention will be described in more detail.

  The invention of claim 1 of the present invention provides a radiation image conversion panel in which a photostimulable phosphor layer having a CsBr: Eu stimulable phosphor on a support is formed by a vapor deposition method (vapor phase method). When the cross section of the photostimulable phosphor layer is excited from the support side to the phosphor layer surface side by an excitation light source, the layer having a low emission intensity and a layer having a high emission intensity are alternately laminated. The radiation image conversion panel is a feature, and the object of the present invention can be achieved by these configurations.

  In the present invention, it is possible to observe that a layer having a low emission intensity and a layer having a high emission intensity in the cross section of the photostimulable phosphor layer are alternately laminated by an excitation light source such as an electron beam or an ultraviolet ray. By using the cathodoluminescence method using an electron beam, it becomes possible to observe more clearly.

  The fact that layers with low emission intensity and layers with high emission intensity are alternately laminated means that the crystal structure of the photostimulable phosphor is discontinuous, and these photostimulable phosphors It has been found that the discontinuity of the crystal structure reduces the stress strain between the support and the phosphor layer and improves the adhesion of the film.

  From the viewpoint of giving practical adhesion, it is preferable to repeat at least two layers of a low emission intensity layer and a high emission intensity layer from the viewpoint of achieving both image quality characteristics (brightness) and adhesion. The repetition is more preferably 2 to 64 layers, still more preferably 4 to 32 layers, and particularly preferably 4 to 16 layers.

  When the repetition exceeds 64 layers, the luminance is drastically reduced, and when it is less than 2 layers, the adhesion is reduced.

  The invention of claim 2 is a method of manufacturing a radiation image conversion panel according to the present invention, wherein a plurality of evaporation sources and a plurality of evaporation sources corresponding to the plurality of evaporation sources are provided in the vacuum vessel. When the radiation image conversion panel according to claim 1 is manufactured using the vapor deposition apparatus having the shutter, the evaporation from the plurality of evaporation sources is alternately performed, and each of the plurality of evaporation sources is opened and closed by opening and closing the shutter. This is a method of manufacturing a radiation image conversion panel characterized by discontinuous evaporation, and the radiation image conversion panel of the present invention can be obtained by the manufacturing method.

  An example of the vapor deposition apparatus is shown in FIG. Fig.1 (a) is a top view of this vapor deposition apparatus, FIG.1 (b) is a front view of this vapor deposition apparatus.

  1A and 1B show that the shutter 4-1 of the evaporation source 3-1 is open and evaporation is performed only from the evaporation source 3-1. In the present invention, FIG. 2 shows that the evaporation from the plurality of evaporation sources is discontinuously performed by opening and closing the shutter. This is because the shutter 4-1 is opened and the evaporation source 3-1 is started to evaporate, and after the evaporation is finished by closing the shutter, the shutter 4-2 is opened after a certain time, and the evaporation source 3-2 is opened. Is the start of evaporation.

  As for the evaporation source installation mode, Japanese Patent Laid-Open No. 2003-247061 discloses a method of continuously supplying raw materials to form a thick film. However, the evaporation source temperature must be kept constant and uniform. Accompany. In addition, a method using a large evaporation source is insufficient in temperature uniformity and stabilization of the evaporation source. The use of a plurality of evaporation sources is excellent in achieving both high image quality and adhesion.

  In FIG. 1, reference numeral 2-1 denotes a support holder, and 2-2 denotes a support.

  The photostimulable phosphor layer of the present invention is formed by a vapor deposition method.

  Vapor deposition, sputtering, CVD, ion plating, and others can be used as the vapor deposition method of the photostimulable phosphor.

  In the present invention, for example, the following methods can be mentioned.

In the first vapor deposition method, after the support is installed in the vapor deposition apparatus, the inside of the apparatus is evacuated to a vacuum of about 1.333 × 10 ⁻⁴ Pa. Next, at least one of the photostimulable phosphor is heated and evaporated by a resistance heating method, an electron beam method, or the like to grow the photostimulable phosphor 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 deposition object 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. Further, in the above evaporation process, it may be deposited by introducing Ar, O _2, H ₂ etc. of the gas if necessary.

In the sputtering method as the second method, the support is placed in the sputtering apparatus in the same manner as the vapor deposition method, and then the inside of the apparatus is evacuated to a vacuum of about 1.333 × 10 ⁻⁴ Pa, and then sputtered. An inert gas such as Ar, Ne or the like is introduced into the apparatus as a working gas to a gas pressure of about 1.333 × 10 ⁻¹ Pa.

  Next, the photostimulable phosphor is grown to a desired thickness on the support surface by sputtering using the photostimulable phosphor as a target. In this sputtering step, various application processes can be used as in the vapor deposition method.

  The third method is a CVD method, and the fourth method is an ion plating method.

  The growth rate of the photostimulable phosphor layer in the vapor deposition method is preferably 0.05 μm / min to 300 μm / min. When the growth rate is less than 0.05 μm / min, the productivity of the radiation image conversion panel of the present invention is low, which is not preferable. On the other hand, when the growth rate exceeds 300 μm / min, it is difficult to control the growth rate.

  When the radiation image conversion panel is obtained by the above-described vacuum deposition method, sputtering method, etc., since there is no binder, the packing density of the stimulable phosphor can be increased, and preferable radiation image conversion in terms of sensitivity and resolution. A panel is obtained.

  The crucible used for vapor deposition differs depending on the heating method such as a resistance heating method, a halogen heating method, and an EB (electron beam) method.

  The film thickness of the photostimulable phosphor layer varies depending on the sensitivity of the intended radiation image conversion panel to radiation, the type of stimulable phosphor, etc., but is preferably selected from the range of 10 μm to 2000 μm, preferably 50 μm to More preferably, it is selected from 1000 μm.

  The crystals of the stimulable phosphor layer made of columnar crystals are formed into independent elongated columnar shapes by a method of supplying vapor of the stimulable phosphor or the raw material at a specific incident angle and vapor phase growth (deposition) on the support. A photostimulable phosphor layer made of crystals can be obtained. The incident angle of the stimulable phosphor vapor flow during vapor deposition may be perpendicular to the normal direction of the support or may be oblique with a certain degree of accuracy. In the case of oblique incidence, the columnar crystal can grow at a growth angle that is approximately half the incidence angle. Moreover, a molecular vapor deposition film can also be provided by vapor-depositing near normal temperature.

  In these cases, it is appropriate that the distance between the shortest part of the support and the crucible is set to approximately 10 cm to 60 cm in accordance with the average range of the stimulable phosphor. In addition, the thickness of the columnar crystal tends to become thinner as the temperature of the support decreases.

  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. The evaporation source is not necessarily a stimulable phosphor, and may be a mixture of a stimulable phosphor material.

  Moreover, you may dope an activator afterwards with respect to the base material of fluorescent substance. For example, after depositing only RbBr as a base material, Tl as 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.

  Doping can be performed by thermal diffusion and ion implantation of a doping agent (activator) in the base layer of the formed phosphor.

  In the stimulable phosphor layer composed of these columnar crystals, in order to reduce the haze ratio, the size of the columnar crystals (the cross-sectional area of each columnar crystal when the columnar crystals are observed from a plane parallel to the support) can be reduced. The average value of the diameter in terms of a circle and calculated from a microphotograph including at least 100 columnar crystals in the visual field is preferably about 1 to 50 μm, and more preferably 1 to 30 μm.

  The size of the gap between the columnar crystals is preferably 30 μm or less, more preferably 5 μm or less. That is, when the gap exceeds 30 μm, the scattering of the laser light in the phosphor layer increases and the sharpness decreases.

  As the support used in the radiation image conversion panel of the present invention, various polymer materials, glass, metal, etc. are used, for example, plate glass such as quartz, borosilicate glass, chemically tempered glass, or cellulose acetate film, A polyester film, a polyethylene terephthalate film, a polyamide film, a polyimide film, a triacetate film, a polycarbonate film or other plastic film, a metal sheet of aluminum, iron, copper, chromium, or a metal sheet having a coating layer of hydrophilic fine particles is preferable. The surface of these supports may be a smooth surface, or may be a mat surface for the purpose of improving the adhesion to the stimulable phosphor layer. Moreover, in this invention, in order to improve the adhesiveness of a support body and a photostimulable phosphor layer, you may provide an adhesive layer in advance on the surface of a support body as needed.

  The thickness of these supports varies depending on the material of the support used, but is generally 80 μm to 2000 μm, and more preferably 80 μm to 1000 μm from the viewpoint of handling.

  In addition, the gap between the columnar crystals may be filled with a filler or the like, and in addition to reinforcing the stimulable phosphor layer, it may be filled with a high light absorption substance, a high light reflectance substance, or the like. Thus, in addition to providing the above-mentioned reinforcing effect, it is effective for reducing the light diffusion in the lateral direction of the stimulated excitation light incident on the stimulable phosphor layer.

  A highly reflective substance refers to a substance having a high reflectivity with respect to stimulated excitation light (500 to 900 nm, particularly 600 to 800 nm). For example, white pigments such as aluminum, magnesium, silver, indium, and other metals In addition, a color material in the green to red region can be used. White pigments can also reflect stimulated emission.

Examples of the white pigment include TiO ₂ (anatase type, rutile type), MgO, PbCO ₃ · Pb (OH) ₂ , BaSO ₄ , Al ₂ O ₃ , M (II) FX (where M (II) is Ba). , Sr, and Ca, and X is a Cl atom or a Br atom.), CaCO ₃ , ZnO, Sb ₂ O ₃ , SiO ₂ , ZrO ₂ , lithopone (BaSO ₄ ZnS), magnesium silicate, basic silicate, basic lead phosphate, aluminum silicate and the like.

  These white pigments have a strong hiding power and a high refractive index, so that it is possible to easily scatter scattered light by reflecting or refracting light, and to significantly improve the sensitivity of the resulting radiation image conversion panel. it can.

  In addition, as a material having a high light absorption rate, for example, carbon black, chromium oxide, nickel oxide, iron oxide, and the like and a blue color material are used. Among these, carbon black absorbs stimulated light emission.

  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.

  In addition, 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.

Examples of the inorganic color material include inorganic pigments such as ultramarine, for example, cobalt blue, cerulean blue, chromium oxide, and TiO ₂ —ZnO—Co—NiO.

  That is, the surface of the support may be a smooth surface, or the surface of the support may be a matte surface for the purpose of improving the adhesion to the stimulable phosphor layer.

  Moreover, in this invention, in order to improve the adhesiveness of a support body and a photostimulable phosphor layer, you may provide an adhesive layer in advance on the surface of a support body as needed.

  The thickness of the support varies depending on the material of the support used, but is generally 80 to 2000 μm, and more preferably 80 to 1000 μm from the viewpoint of handling.

  Moreover, the photostimulable phosphor layer of the present invention may have a protective layer.

  The protective layer may be formed by directly applying a protective layer coating solution on the photostimulable phosphor layer, or a protective layer separately formed in advance may be adhered on the photostimulable phosphor layer. Alternatively, a means for forming a stimulable phosphor layer on a separately formed protective layer may be taken.

  Materials for the protective layer include cellulose acetate, nitrocellulose, polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene, polyvinylidene chloride, nylon, polytetrafluoroethylene, polytrifluoride-chloride. Usual protective layer materials such as ethylene, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer are used. In addition, a transparent glass substrate can be used as a protective layer.

Further, this protective layer may be formed by laminating inorganic substances such as SiC, SiO ₂ , SiN, Al ₂ O ₃ by vapor deposition, sputtering, or the like.

  The thickness of these protective layers is preferably 0.1 to 2000 μm.

  In addition, when excited by light energy, it is necessary to separate the reflected light of the stimulated excitation light from the stimulated emission emitted from the stimulable phosphor layer, and it is emitted from the stimulable phosphor layer. Photoelectric converters that receive light emission generally have high sensitivity to light energy with a short wavelength of 600 nm or less, so that the stimulated emission emitted from the stimulable phosphor layer has a spectral distribution in the short wavelength region as much as possible. What you have is desirable.

  The emission wavelength range of the photostimulable phosphor of the present invention is 300 to 500 nm, while the photostimulable excitation wavelength range is 500 to 900 nm, which satisfies the above-mentioned conditions at the same time. Recently, downsizing of diagnostic devices has progressed. A semiconductor laser that has a high output power and is easy to be compacted is preferably used for reading an image of the radiation image conversion panel, and the wavelength of the laser light is preferably 680 nm. The stimulable phosphor incorporated in the panel exhibits very good sharpness when using an excitation wavelength of 680 nm.

  That is, all of the photostimulable phosphors of the present invention emit light having a main peak at 500 nm or less, the photostimulated excitation light is easily separated, and coincides well with the spectral sensitivity of the light receiver, so that light can be received efficiently. The sensitivity of the image receiving system can be increased.

Examples of lasers include He—Ne laser, He—Cd laser, Ar ion laser, Kr ion laser, N ₂ laser, YAG laser and its second harmonic, ruby laser, semiconductor laser, various dye lasers, copper vapor There are metal vapor lasers such as lasers. Normally, a continuous wave laser such as a He—Ne laser or an Ar ion laser is desirable, but a pulsed laser can also be used if the scanning time and pulse of one pixel of the panel are synchronized.

  In addition, when using a method of separating light emission delay as disclosed in JP-A-59-22046, it is preferable to use a pulsed laser rather than a continuous wave laser.

  Among the various laser light sources described above, the semiconductor laser is particularly preferably used because it is small and inexpensive and does not require a modulator.

  For example, in the case of a practically preferable combination in which the photostimulation excitation wavelength is 500 to 900 nm and the photostimulation emission wavelength is 300 to 500 nm, examples of the filter include C-39, C-40, and V-40 manufactured by Toshiba Corporation. Purple-blue glass filters such as V-42, V-44, Corning 7-54, 7-59, Spectrofilm BG-1, BG-3, BG-25, BG-37, BG-38, etc. Can be used. If an interference filter is used, a filter having an arbitrary characteristic can be selected and used to some extent. Any photoelectric conversion device may be used as long as it can convert a change in light quantity into a change in electronic signal, such as a photoelectric tube, a photomultiplier tube, a photodiode, a phototransistor, a solar cell, or a photoconductive element.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, the embodiment of this invention is not limited to these.

Example 1:
Using a 0.5 mm thick Al plate (100 mm × 100 mm) as a support, a stimulable phosphor (CsBr: 0.0001Eu) was deposited on one side of the support using the apparatus shown in FIG. A photostimulable phosphor layer was formed.

  First, the support body 2-2 was installed in the evaporation source 3-1 to 3-4 which filled the resistance heating crucible with the said phosphor raw material as a vapor deposition material, and the support body holder 2-1. The distance between the support and the resistance heating crucible was 60 cm.

Subsequently, the inside of the vapor deposition apparatus 1 is once evacuated, N ₂ gas is introduced and the degree of vacuum is adjusted to 0.1 Pa, and then the support temperature is adjusted with a heating lamp (not shown) while rotating the support holder. Maintained at 100 ° C.

  Next, the resistance heating crucible 3-1 was first heated, and then the shutter 4-1 was opened to perform vapor deposition for 30 minutes, and then the shutter was closed to complete the evaporation from the crucible 3-1. Evaporation from the crucibles 3-2, 3-3, and 3-4 was performed in the same manner, and the radiation image conversion panel 1 of Example 1 having a film thickness of 400 μm was produced.

Example 2:
Except for using a vapor deposition apparatus (not shown) capable of installing eight crucibles and evaporating eight crucibles sequentially in the same manner as in the first embodiment with the evaporation time of one crucible being 15 min. 1 was used to produce the radiation image conversion panel 2 of Example 2 having a film thickness of 400 μm.

Example 3:
Except for using a vapor deposition apparatus (not shown) capable of installing 16 crucibles and evaporating 16 crucibles in the same manner as in Example 1 with an evaporation time of one crucible being 7.5 min. A radiation image conversion panel 3 of Example 3 having a film thickness of 400 μm was produced in the same manner as in Example 1.

Comparative Example 1:
A radiographic image conversion panel 4 of Comparative Example 1 having a film thickness of 400 μm was produced in the same manner as in Example 1 except that eight crucibles were evaporated at the same time in Example 1.

Comparative Example 2:
A radiation image conversion panel 5 of Comparative Example 2 having a film thickness of 400 μm was produced in the same manner as in Example 1 except that the four crucibles were simultaneously evaporated in Example 1.

  About each radiographic image conversion panel, the brightness | luminance was measured in accordance with the method shown below.

<Luminance (sensitivity) measurement>
For the measurement of luminance, each radiation image conversion panel is irradiated with X-rays having a tube voltage of 80 kVp from the back side of the phosphor sheet support, and then the panel is excited by operating with He-Ne laser light (633 nm). The stimulated luminescence emitted from the body layer is received by a photoreceiver (photoelectron image multiplier of spectral sensitivity S-5), the intensity is measured, this is defined as the brightness, and the brightness of the radiation conversion panel 4 is Displayed as a relative value of 1.0.

<Evaluation of adhesion (with film)>
Using the radiation image conversion panels 1 to 5, an adhesive tape is applied to the phosphor layer surface of each panel, and the area% where the phosphor layer is attached to the support when the tape is peeled off is measured and shown below. Adhesion was evaluated according to standards. The evaluation results are shown in Table 1.

A: The area where the phosphor layer is attached to the support is 100%.
○: The area where the phosphor layer is attached to the support is 80% or more and less than 100% Δ: The area where the phosphor layer is attached to the support is 60% or more and less than 80% ×: The phosphor layer is the support Less than 60% area attached to

  As is apparent from Table 1, it can be seen that the radiation image conversion panel and the manufacturing method thereof of the present invention are superior in both adhesion and image quality characteristics (luminance) as compared with the comparison.

It is the schematic which shows an example of the vapor deposition apparatus used for this invention. It is a pattern figure which shows an example of opening and closing of the shutter on the evaporation source of this invention.

Explanation of symbols

1 Vacuum container 3-1 to 3-4 Evaporation source 4-1 to 4-4 Shutter

Claims (2)

In a radiation image conversion panel in which a photostimulable phosphor layer having a CsBr: Eu photostimulable phosphor is formed on a support by a vapor deposition method (vapor phase method), a cross section of the photostimulable phosphor layer is shown. A radiation image conversion panel, wherein a layer having a low emission intensity and a layer having a high emission intensity are alternately laminated when excited from the support side to the phosphor layer surface side by an excitation light source. 2. When the radiation image conversion panel according to claim 1 is manufactured using a vapor deposition apparatus having a plurality of evaporation sources and a plurality of shutters corresponding to the plurality of evaporation sources in a vacuum vessel, evaporation from the plurality of evaporation sources. A method of manufacturing a ray image conversion panel characterized in that the steps are alternately performed and the intervals between the evaporations of the plurality of evaporation sources are made discontinuous by opening and closing the shutter.

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