JP2000346996A - Radiation image conversion panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radiation image conversion panel that has high resistance to flaws without degrading the quality of formed images. SOLUTION: In the radiation image conversion panel 10, there is a phosphor layer 12 containing stimulable phosphors on a support 11 and a protective layer 13 on the layer 12, and the average surface roughness Ra of a surface 13a is 0.10<=Ra<=0.45 μm. Moreover, the support 11 is transparent and the average surface roughness Ra of the reverse side of it is 0.10<=Ra<=0.45 μm. The radiation image conversion panel 10 is used at least for a method for converting radiation images through the condensation of stimulable luminescent light from the reverse side of the support 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a radiation image conversion panel utilizing the characteristics of a stimulable phosphor.

[0002]

2. Description of the Related Art As an alternative to the conventional radiographic method, for example, a radiation image conversion method using a stimulable phosphor as described in JP-A-55-12145 is known. This method uses a radiation image conversion panel (a stimulable phosphor sheet) containing a stimulable phosphor, and transmits radiation transmitted through a subject or emitted from a subject to the stimulable phosphor of the panel. Absorb the radiation energy accumulated in the stimulable phosphor by stimulating the stimulable phosphor with electromagnetic waves (excitation light) such as visible light and infrared light in a time series manner. (Stimulated emission light), the fluorescence is photoelectrically read from the light irradiation side to obtain an electric signal, and a radiation image of a subject or a subject is reproduced as a visible image based on the obtained electric signal. Things. This method has the advantage that an information-rich radiographic image can be obtained with a much smaller exposure dose than conventional radiography. Therefore, this method is very useful especially in X-ray photography for medical diagnosis. further,
In the conventional radiographic method, the radiographic film to be used is consumed each time a radiograph is taken, whereas in the radiographic image conversion method, the reproduced visible image can be erased. The conversion panel can be used repeatedly, which is advantageous in terms of resource conservation and economic efficiency.

Further, as a method developed from the radiation image conversion method, there has been proposed a double-sided condensing reading method in which fluorescence emitted from a stimulable phosphor is read on both the front and rear surfaces of a panel (Japanese Patent Laid-Open No. 55-55). -87970 and the like). According to this method, from both the front surface and the back surface of the panel,
Since the fluorescent light is collected, the light collection efficiency is improved, and the energy intensity distribution in the depth direction of the panel can be obtained as radiation image information.

The radiation image conversion panel used in the radiation image conversion method has, as a basic structure, a support and a stimulable phosphor layer provided on the surface of the support. A protective layer is usually provided on the surface of the stimulable phosphor layer (the surface not facing the support) for the purpose of protecting the phosphor layer from chemical alteration or physical impact. Have been.
The protective layer is formed by applying a solution prepared by dissolving a transparent organic polymer substance such as a cellulose derivative or polymethyl methacrylate in an appropriate solvent onto the phosphor layer, or polyethylene. An organic polymer film such as terephthalate or a sheet for forming a protective film such as a transparent glass plate is separately formed and provided on the surface of the phosphor layer using an appropriate adhesive, or an inorganic compound is deposited on the phosphor by vapor deposition or the like. Those formed on a layer are known.

In carrying out the radiation image conversion method, the radiation image conversion panel includes radiation irradiation (recording of a radiation image), irradiation of excitation light (reading of a recorded radiation image), irradiation of erasing light (remaining radiation image). Erasure). The transfer of the radiation image conversion panel to each step is performed by using a conveying means such as a belt or a roller. When one cycle is completed, the panels are usually stacked and stored. However, when the radiation image conversion panel having the above configuration is used repeatedly in this manner, for example, stains and scratches are generated on the surface of the protective layer, and as a result, the image quality of the radiation image formed by the radiation image conversion panel gradually decreases. Tend to decrease. For the purpose of preventing the occurrence of scratches and the like due to such repeated use, for example, Japanese Patent Application Laid-Open No. 03-246498 proposes a method of further providing a friction coefficient reducing layer on the surface of a protective layer. Also, JP-A-04-310900, JP-A-08-1
JP-A-90000 and JP-A-10-123297 propose a method of using a specific resin for the protective layer to improve the scratch resistance.

[0006]

However, it is difficult to completely prevent abrasion or the like from occurring on the panel surface of a radiation image conversion panel that is repeatedly transported and used. For example, in Japanese Patent Application Laid-Open No. 05-247456,
A stimulable phosphor screen in which the surface of a protective layer has an embossed structure is disclosed. This screen is useful in that a protective layer having an embossed structure is provided on the phosphor layer, so that friction and the like during handling can be reduced.
However, if the surface of the panel is made uneven by embossing or the like, the scratch resistance can be improved,
On the other hand, stimulating excitation light is scattered, and the quality of the formed image is reduced.

An object of the present invention is to solve the above problems. That is, an object of the present invention is to provide a radiation image conversion panel having high scratch resistance without deteriorating the image quality of a formed image.

[0008]

In order to achieve the above object, the present invention provides a phosphor layer containing a stimulable phosphor on a support, and a protective layer on the phosphor layer. A radiation image conversion panel characterized in that the average surface roughness Ra satisfies the following relational expression. 0.10 μm ≦ Ra ≦ 0.45 μm

[0009] In order to achieve the above object, the present invention provides a phosphor comprising a phosphor layer containing a stimulable phosphor on a transparent support, and a protective layer thereon. A radiation image conversion panel for use in a radiation image conversion method for condensing stimulated emission light from the back surface of the device, wherein the average surface roughness Ra of the back surface satisfies the following relational expression. It is a panel. 0.10 μm ≦ Ra ≦ 0.45 μm

The thickness of the protective layer is preferably 5 μm or more and 20 μm or less.

In the radiation image conversion panel according to the present invention, at least the surface on which the stimulating light is condensed has the average surface roughness Ra in the above-mentioned range. The radiation image conversion panel is hardly scratched (has scratch resistance) on the front and / or back surface of the panel.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The radiation image conversion panel of the present invention is changed to a single-sided radiation image conversion panel (radiation image conversion panel used for a method of concentrating photostimulated light from the photostimulable phosphor layer side). FIG. 1 shows a configuration example of the applied layer. The radiation image conversion panel 10 includes a support 11 on which a phosphor layer 12 containing a stimulable phosphor is provided, and a protective layer 13 is further provided thereon. The surface 13a of the protective layer 13 has an average surface roughness Ra of 0.1 by embossing or the like.
It is adjusted so that 0 μm ≦ Ra ≦ 0.45 μm.

The layer constitution of the radiation image conversion panel of the present invention is as follows.
The configuration is not limited to the configuration illustrated in FIG. 1, and may be, for example, a configuration in which a light adjustment layer and the like are further provided on the protective layer. When an upper layer is further provided on the protective layer, the surface of the layer needs to have an average surface roughness Ra in the above range.

When radiation of a predetermined energy is incident from the arrow direction I in FIG. 1, the radiation passes through the protective layer 13 and is absorbed by the stimulable phosphor contained in the phosphor layer 12. Thereafter, upon irradiation with excitation light such as visible light or infrared light, the stimulable phosphor emits the energy of the absorbed radiation as fluorescence. The fluorescent light emitted in the direction of arrow L in FIG. 1 is read by a light-collecting device (not shown), converted into an electric signal, and the radiation is converted into a visible image based on the electric signal.

FIG. 2 shows an example of a layer configuration in which the radiation image conversion panel of the present invention is applied to a double-sided condensing radiation image conversion panel. In the radiation image conversion panel 20 shown in FIG. 2, a phosphor layer 22 containing a stimulable phosphor is provided on a transparent support 21, and a protective layer 23 is further provided thereon.
Front surface 23a of protective layer 23 and back surface 2 of transparent support 21
1a has an average surface roughness Ra by embossing or the like.
Is adjusted to 0.10 μm ≦ Ra ≦ 0.45 μm.

When the radiation image conversion panel of the present invention is applied to a double-sided condensing radiation image conversion panel, the layer configuration is not limited to the configuration shown in FIG. May be provided. When another layer is provided on the protective layer, the surface of the uppermost layer needs to have an average surface roughness Ra in the above range. Also, a slip layer or the like may be provided on the back surface 21a of the support 21, and in this case, the surface of the layer (the surface not in contact with the support) needs to have an average surface roughness Ra in the above range. .

When radiation having a predetermined energy is incident from the arrow direction I in FIG. 2, the radiation passes through the protective layer 23 and is absorbed by the stimulable phosphor contained in the phosphor layer 22. Thereafter, upon irradiation with excitation light such as visible light or infrared light, the stimulable phosphor emits the energy of the absorbed radiation as fluorescence. However, since the support 21 is transparent, the fluorescence is as shown in FIG. Light can be collected in the directions of arrows L and L '(double-sided light reading method). The fluorescent light emitted in the L and L 'directions is read by a light-collecting device (not shown), converted into an electric signal, and the radiation is converted into a visible image based on the electric signal.

In the radiation image conversion panel shown in FIGS. 1 and 2, the layer configuration can be arbitrarily selected according to the purpose, application, etc. of the radiation image conversion panel. For example, support 1
The phosphor layer 12 or 22 is provided to enhance the bond between the phosphor layer 1 or 21 and the phosphor layer 12 or 22 or to improve the sensitivity or image quality (sharpness, granularity) as a radiation image conversion panel. Side support 11
Alternatively, an adhesiveness-imparting layer made of a polymer substance such as gelatin is provided on the surface of 21, or a light-reflective layer made of a light-reflective substance such as titanium dioxide or a light-absorbing substance made of a light-absorbing substance such as carbon black. Layers and the like can also be provided. In addition, the supports 11, 21 and the phosphor layer 1
Between 2 and 22, a conductive layer containing a conductive substance may be provided.

As the support, a film or sheet made of a plastic material can be used. Examples of the plastic material include polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, and aramid resin. The support has sufficient strength as a support and may be made of any material as long as it has sufficient adhesion to the phosphor layer.
When the radiation image conversion panel is used as a panel for double-sided condensing reading, the support needs to be transparent. Here, “transparent” refers to a property that does not substantially absorb irradiated radiation, excitation light, and emitted stimulating light.

The thickness of the support is usually 10 μm to 2 mm.
And preferably from 100 μm to 1 mm.

The stimulable phosphor contained in the phosphor layer is
After the irradiation with the radiation, the phosphor can be widely used as long as the phosphor exhibits a photostimulated luminescence by irradiation with the excitation light. From a practical point of view, after irradiation,
With excitation light of 00 to 900 nm, a wavelength of 300 to 50
Phosphors exhibiting a stimulated emission of 0 nm are preferred. Among known stimulable phosphors, europium- or cerium-activated alkaline earth metal halide-based phosphors and cerium-activated rare earth oxyhalide phosphors are particularly preferable because they exhibit high-luminance stimulable light emission. Also, Japanese Patent Application Laid-Open No. 2-19 / 1990
The stimulable phosphors described in detail in JP-A-3100 and JP-A-4-310900 can also be suitably used.

The phosphor layer contains the stimulable phosphor described above,
Further, a binder for supporting the phosphor in a dispersed state may be contained. As the binder, conventionally known materials, for example, epoxy resin, polyurethane resin, nitrocellulose, linear polyester, polyalkyl (meth) acrylate, and the like can be used alone or in combination of two or more. Further, the phosphor layer may be composed of only the aggregate of the stimulable phosphor, or may be formed by impregnating the polymer between the gaps of the aggregate of the stimulable phosphor. You may. The phosphor layer may further contain a colorant, a discoloration inhibitor, a dispersant, a plasticizer, a conductive agent, a crosslinking agent, and the like, if desired.

The phosphor layer can be provided on a support by, for example, the following known method. First, the stimulable phosphor and, if desired, a binder are added to a solvent, and the binder is sufficiently dissolved to prepare a phosphor layer coating solution in which the stimulable phosphor is uniformly dispersed. The mixing ratio of the stimulable phosphor and the binder in the coating solution varies depending on the kind of the phosphor used, the characteristics of the target panel, and the like, but is generally 1: 1 to 1: 1 by weight. Selected from a range of mixing ratios of 100,
It is preferable to select from a range of a mixing ratio of 1: 8 to 1:40. Next, the coating solution is applied to the surface of a support by a doctor blade, a roll coater, a knife coater or the like (when an intermediate layer such as an adhesion layer is provided between the support and the phosphor layer, the surface of the intermediate layer). To form a coating film. Thereafter, the coating film is dried to complete the formation of the phosphor layer. Incidentally, the thickness of the phosphor layer is usually from 20 μm to 1 mm, preferably from 50 μm to 500 μm.

The phosphor layer may be formed by, for example, separately applying a coating solution on a temporary support such as a glass plate, a metal plate, or a plastic sheet, in addition to the method of applying the coating solution on the surface of the support. Is dried to form a phosphor layer, and then the phosphor layer is peeled off from the temporary support, and this is pressed onto a support using a calender roll or the like, and a method of laminating, an adhesive or the like is used. It may be formed by a method in which the support and the phosphor layer are bonded together.

The radiation image conversion panel of the present invention has a protective layer on the phosphor layer. The thickness of the protective layer is preferably from 5 to 20 μm. When another layer is provided on the protective layer, the total of the layer thickness of the layer and the protective layer is preferably within the above range. The material forming the protective layer is not particularly limited, and can be widely selected from known materials. For example, a polyurethane resin, a polyacryl resin, a cellulose derivative, polymethyl methacrylate, a polyester resin, an epoxy resin, a fluororesin, and the like can be given. Even if the protective layer is made of one type of resin material,
It may be composed of two or more materials. The protective layer is
It is preferably transparent to the incident radiation and the fluorescence from the stimulable phosphor.

It is preferable to use a fluororesin as a material for forming the protective layer, since the antifouling property and the flaw resistance of the protective layer are improved. Examples of the fluororesin include, for example,
-190000 and JP-A-10-12329
No. 7, etc., polymers of fluorine-containing olefins (fluoroolefins) (for example, polytetrafluoroethylene, polychlorotrifluoroethylene,
And a copolymer containing a fluoroolefin as a copolymer component (a tetrafluoroethylene-hexafluoropropylene copolymer, a fluoroolefin-vinyl ether copolymer, etc.). Further, it is preferable to use a polysiloxane skeleton-containing oligomer or a perfluoroalkyl group-containing oligomer together with the fluororesin, since the antifouling property and the antifouling property are further improved.

The protective layer is provided on the phosphor layer (in the case where an intermediate layer such as an adhesion layer is provided between the phosphor layer and the protective layer, on the intermediate layer) in the same manner as the phosphor layer. be able to.
The protective layer may be formed from a transparent film, and examples of the transparent film include transparent films such as polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, and aramid resin. Further, a layer made of the resin may be further provided on the transparent film, and this may be used as a protective layer. When the protective layer is made of the transparent film, the transparent film can be bonded onto the phosphor layer using an adhesive or the like. The protective layer may contain fine particles such as a crosslinking agent, a coloring agent, a discoloration inhibitor, a conductive agent, and a light scattering agent, if desired.

The surface of the radiation image storage panel of the present invention has an average surface roughness Ra of 0.10 μm or more and 0.45 μm or less. When the surface average roughness Ra is less than 0.10 μm, the effect of improving the scratch resistance of the surface of the radiation image storage panel is not exhibited. On the other hand, when the surface roughness Ra exceeds 0.45 μm, light emission unevenness occurs due to scattering of excitation light and the like, and the image quality of a formed image deteriorates. In addition, the surface of the radiation image change panel referred to here refers to the surface of the outermost layer located on the side opposite to the side where the support is located when the phosphor layer is viewed as a center, and the protective layer is the outermost layer. In this case, the surface of the protective layer becomes the surface of the radiation image storage panel. Usually, it refers to the surface on the side on which the stimulable luminescent light emitted by the stimulable phosphor is observed.
Shows 23a. The average surface roughness Ra is defined as JI
It refers to the center line average surface roughness Ra value measured according to SB0651.

As a method of adjusting the average surface roughness Ra of the surface of the radiation image conversion panel, for example, a method of applying a coating liquid for a protective layer and drying the coating film to generate cracks or the like in the step of drying the coating film; Examples thereof include a method of adding fine particles to a coating liquid to form irregularities on the surface, a method of sandblasting, and a method of forming irregularities on the protective layer by embossing. Among them, the embossing method is preferable because the processing is easy and the average surface roughness Ra can be easily controlled. Embossing is a technique in which an embossing roll having an uneven pattern on the surface is pressed while heating the sheet or the like to transfer the uneven pattern to the sheet surface. The average surface roughness Ra of the panel surface can be adjusted to the above range by adjusting the processing conditions such as the depth of the uneven pattern on the embossing roll surface and the temperature and pressure during embossing. When producing a radiation image conversion panel having a surface roughness Ra in the above range, the surface roughness Ra of the embossing roll is preferably 1.0 μm or more and 4.0 μm or less. Further, it is preferable that the surface of the embossing roll has an irregular concavo-convex shape formed by combining substantially sinusoidal shapes having different pitches and amplitudes. In the case where the outermost surface layer of the radiation image conversion panel is provided by calendering or the like, embossing may be simultaneously performed using a roll having an uneven pattern during calendering.

When the radiation image conversion panel of the present invention is used as a panel for double-sided condensing reading, the back surface of the radiation image conversion panel also has an average surface roughness Ra of 0.10 μm or more and 0 mm for the same reason as described above. .45 μm or less. Adjustment of the average surface roughness Ra of the back surface can also be performed by the same processing as the processing of the front surface.
The method is preferably performed by a method of sandblasting the back surface of the panel or a method of applying a coating solution containing fine particles to the back surface of the panel. In addition, the back surface of the radiation image conversion panel referred to here refers to the surface of the outermost layer located on the side opposite to the side where the phosphor layer is located when the support is viewed as a center, and the outermost layer is provided. If not, the back surface of the support (the surface on which the phosphor layer is not provided) is the back surface of the radiation image conversion panel.

Further, when the radiation image conversion panel of the present invention is used as a panel for double-sided condensing reading, if the phosphor layer is composed of two or more layers, the distribution of the stimulable phosphor in the phosphor layer will be described. (Or, when a binder or a colorant is contained, the distribution of the binder or the colorant) can be easily adjusted to a desired range, and a radiation image conversion panel capable of forming a high-quality radiation image can be easily manufactured. It is preferred. As a method of laminating the phosphor layers, a first phosphor layer is formed, and then a coating solution for a phosphor layer is applied on the first phosphor layer to form a second phosphor layer. There is a method and a method of laminating the first phosphor layer and the second phosphor layer by lamination.

[0032]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples of the present invention. However, the present invention is not limited to the following examples. Example 1 and Comparative Example 1: Radiation image conversion panel for single-sided condensing reading • Formation of undercoat layer on support Polyethylene terephthalate sheet into which barium sulfate was kneaded (thickness: 350 μm; “Melinex # 99”)
2 "; ICI) was used as a support. A light-shielding layer (about 18 μm thick) made of carbon black, silica, and a binder is provided on one side of the support.
An undercoat layer formed as described below was provided on the other surface.

First, a coating solution for an undercoat layer having the following composition was prepared. 35 g of fine particles of gadolinium oxide (Gd ₂ O ₃ ) (particles having a particle size distribution in which particles having a particle size in the range of 1 to 5 μm account for 90% by weight of all particles) Binder 180 g (soft acrylic resin; “Chris Coat P-1018GS "[20% toluene solution]; Dainippon Ink and Chemicals, Inc.) Plasticizer (phthalic acid ester;"# 10 "; Daihachi Chemical Co., Ltd.) 4 g Conductive agent 12 g (ZnO whisker;" Vanatetra A- 1-1 "; manufactured by Matsushita Amtech Co., Ltd.) Colorant (ultramarine;" SM-1 "; manufactured by Daiichi Kasei Kogyo Co., Ltd.) 0.5 g The above-mentioned components are dispersed and dissolved in methyl ethyl ketone using a propeller mixer, and the undercoat is applied. A coating solution for a layer was prepared. The coating solution was uniformly applied to the surface of the support having no light-shielding layer using a doctor blade, and then the coating was dried to obtain a support on which an undercoat layer was formed.

Formation of Phosphor Layer A coating solution having the following composition was prepared as a coating solution for the phosphor layer. Phosphor (BaFBr _0.85 I _0.15 : Eu ²⁺ ) 200 g Binder 7.1 g (HDI-based polyurethane elastomer; “PANDEX T-5265H” [solid]; manufactured by Dainippon Ink and Chemicals, Inc.) Crosslinker 0.9 g (HDI Coloring agent 0-based polyisocyanate; "Coronate HX" (solid content 100%); Nippon Polyurethane Industry Co., Ltd.) Yellowing inhibitor 2 g (epoxy resin; "Epicoat # 1001"[solid]; Yuka Shell Epoxy Co., Ltd.) 004 g (Gunsei; "SM-1"; manufactured by Daiichi Kasei Kogyo Co., Ltd.) As a solvent, a mixed solvent of methyl ethyl ketone / toluene = 7/3 was used, and the above components were sufficiently dispersed in the solvent with a propeller mixer. A coating solution having a viscosity of 30 ps (25 ° C.) was prepared. The weight ratio between the binder and the phosphor in the coating solution was 1/20.

This phosphor layer coating solution is applied onto a polyethylene terephthalate sheet (temporary support; thickness: 180 μm) coated with a silicone release agent, and dried to form a phosphor layer. The phosphor layer was peeled from the temporary support to obtain a phosphor layer sheet. The phosphor layer sheet and the support are overlapped so that the light-shielding layer of the support and the phosphor layer sheet are in contact with each other, and the pressure is set to 500 kgw / cm ² and the upper roll temperature is set to 75 using a calender roll.
C., a lower roll temperature of 75.degree. C. and a feed speed of 1.0 m / min. By this heating and compression operation, the phosphor layer sheet was completely fused to the light-shielding layer of the support, and the phosphor layer was formed on the support.

Formation of a protective layer A PET film having a thickness of 9 μm (“Lumirror 9D-V07”)
W "; a product of Toray Industries, Inc .; a solution of an unsaturated polyester resin (" Pylon 30SS "; a product of Toyobo Co., Ltd.) is applied and dried, and the adhesive layer (the amount of the applied polyester resin is 2 g /
m ² ). This PET film was adhered to the phosphor layer with an adhesive layer using a laminate roll to form a protective layer (9 μm in thickness).

Embossing After forming the protective layer with a laminating roll, the panel surface (protective layer surface) was continuously embossed under the following conditions. Embossing is chrome material diameter 20c
m, using an emboss roll having an average surface roughness Ra of 2.4 μm, a linear pressure of 30 to 70 kg / cm, and a roll temperature of 4
At 0 to 80 ° C., the uneven pattern was transferred to the sheet surface, and the average surface roughness Ra of the surface was 0.04, 0.10, 0.21,
Radiation image conversion panels of 0.33, 0.45, 0.57, and 0.69 μm were produced, respectively. In addition, a radiation image conversion panel that was not subjected to the embossing process was also manufactured.

The surface of each radiation image conversion panel produced as described above was scratched at a speed of 1 cm / sec using a diamond needle having a tip radius of curvature of 0.1 mm. At this time, the load applied to the radiation image conversion panel is 0 to 10
It was varied in the range of 0 g. Thereafter, the radiation image conversion panel is irradiated with X-rays having a tube voltage of 80 kVp and 10 mR to form an accumulated image of radiation energy. Then, a laser beam having a wavelength of 680 nm is scanned, and the stimulable phosphor in the phosphor layer is scanned. Was excited to emit stimulable fluorescence. The stimulable light emitted from the phosphor layer was collected and converted into an electric signal, which was reproduced as an image on a display device by an image reproducing device. The image quality of the reproduced image and the visibility of the scratch on the panel surface were visually determined, and the following five-step evaluation was performed. A rating of 3 or more was considered acceptable for practical use. From the results of both evaluations, a comprehensive judgment was made on the practicality of the radiation image conversion panel. Table 1 shows the evaluation results.

Image quality of reproduced image 5: The image quality of the reproduced image was extremely high. 4: The image quality of the reproduced image was high. 3: There was no practical problem with the image quality of the reproduced image. 2: The image quality of the reproduced image was low. 1: The image quality of the reproduced image was extremely low.

The visibility of the scratches 5: The minimum load at which the scratches could be recognized on the image quality was 40 g or more. 4: The minimum load at which scratches could be recognized on the image quality was 20 g or more and less than 40 g. 3: The minimum load at which scratches could be recognized on the image quality was 10 g or more and less than 20 g. 2: The minimum load at which scratches can be recognized on the image quality is 5 g or more and 1
It was less than 0 g. 1: The minimum load at which scratches could be recognized on the image quality was less than 5 g.

Comprehensive evaluation ：: Practically sufficient characteristics as a radiation image conversion panel. X: Practically inferior as a radiation image conversion panel.

[0042]

[Table 1]

Example 2 and Comparative Example 2: Radiation image conversion panel for double-sided condensing reading ・ Formation of backside protective layer A polyethylene terephthalate sheet having a thickness of 250 μm and a haze degree (typical) of 27 (“Lumirror S-1”)
0 "(manufactured by Toray Industries, Inc.), a back surface protective layer was formed as follows.

925 g of fluororesin (copolymer of fluoroolefin and vinyl ether; “Lumiflon LF-504X” [30% xylene solution]; Asahi Glass Co., Ltd.) 50 g of crosslinking agent (polyisocyanate; “Sumidur N3500” [ Solid content 100%]; Sumitomo Bayer Urethane Co., Ltd. Slip agent 5 g (alcohol-modified silicone; "X-22-2809" [66% xylene-containing paste]; Shin-Etsu Chemical Co., Ltd.) Organic filler 65 g (melamine-formaldehyde; “Eposter S12” [Average particle size: 1.2 μm]; Nippon Shokubai Co., Ltd. Coupling agent 1 g (acetoalkoxyaluminum diisopropylate; “Preneact ALM”; Ajinomoto Co., Ltd.) Catalyst 3.5 mg ( Dibutyltin dilaurate; "KS1260"; 665 g of methyl ethyl ketone was added to the above components,
A coating liquid for a back surface protective layer adjusted to a viscosity of 3 to 4 cps was obtained. The coating solution for the backside protective layer was applied on one surface of the support, heat-treated at 140 ° C. for 5 minutes, thermally cured, and dried to form a backside protective layer having a thickness of about 2 μm.
The surface roughness Ra of the back surface protective layer was 0.14 μm.

Formation of Conductive Layer Next, a binder (unsaturated polyester resin;
00 "; Toyobo Co., Ltd.) dissolved in methyl ethyl ketone (1000 g of a solution (solid content: 15% by weight)) and a conductive agent (Sb-doped SnO ₂ needle-shaped fine particles;" FSS-10M ").
[30% solid content MEK dispersion]; 5% by Ishihara Sangyo Co., Ltd.
64 g was added to 480 g of methyl ethyl ketone and dispersed to obtain a coating liquid for a conductive layer adjusted to a viscosity of 20 to 30 cps. After applying the coating solution to the other surface of the support (the surface opposite to the surface on which the back surface protective layer is provided), 80 to 12
By drying at a temperature of 0 ° C., a conductive layer having a thickness of about 2 μm was formed.

Formation of Phosphor Layer A coating solution having the following composition was prepared as a phosphor layer coating solution. 10000 g of a tetrahedral phosphor (BaFBr _0.85 I _0.15 : Eu ²⁺ ) 2462 g of a binder (HDI-based polyurethane elastomer; “Pandex T-5265H” [dissolved in methyl ethyl ketone to a solid content of 13% by weight]; 30 g of cross-linking agent (manufactured by Dainippon Ink and Chemicals, Inc.) (HDI polyisocyanate; "Coronate HX" [solid content 100%]; manufactured by Nippon Polyurethane Industry Co., Ltd.) Yellowing inhibitor 150 g (epoxy resin; "Epicoat # 1001" [solid The above components were added to 690 g of methyl ethyl ketone, and dispersed for 1 hour at 2500 rpm using a dispersing machine (capacity: 10 liters; stirred by a 140 mm diameter cross blade).
A coating solution having a viscosity of 30 ps was prepared (binder / phosphor weight ratio = 1/20).

Using about half of the phosphor layer coating solution,
A 400-mm wide coating is applied on a polyethylene terephthalate sheet (temporary support; 190 μm thick) coated with a silicone release agent, and dried to form a phosphor layer. It was rolled up and peeled from the temporary support (at this time, the temporary support was wound at 25 g / cm) to obtain a phosphor layer sheet A (film thickness 200 μm). Similarly, a phosphor layer sheet B (film thickness: 200 μm) was obtained using the remaining half of the phosphor layer coating solution.

The phosphor layer sheet A obtained as described above
And B were each laminated on the support using a calender. First, the phosphor layer sheet A is passed through a tension pickup roll, and the coated surface of the phosphor layer sheet A (the surface opposite to the peeled surface when the phosphor layer sheet A is peeled from the temporary support) is A laminate obtained by laminating the phosphor layer sheet A and the support so as to be in contact with the conductive layer surface of the support was passed through a pair of 200 mmφ metal rolls with the support side down, and calendering was performed. Processing conditions are
Under the conditions of 50 g / cm of the tension of the phosphor layer sheet A, 600 g / cm of the feed tension of the support, a total load of 2.2 tons, an upper roll temperature of 60 ° C., a lower roll temperature of 60 ° C., and a feed speed of 3.0 m / min. The laminate was continuously heated and compressed, and the laminate was wound up at a tension of 400 g / cm. The tension of the phosphor layer sheet A was controlled by a signal feedback from a tension pickup roll so as to have a variation range of ± 10%.

The laminated body subjected to the calendering process is set in a delivery port of a calender, and the phosphor layer sheet B is superimposed on the laminated body (the peeled surface of the phosphor layer sheet B and the surface of the phosphor layer sheet A). ), With the support side down, 200 m
The sheet was passed through a pair of mφ metal rolls to perform a calendering process. The processing conditions are the tension 50 of the phosphor layer sheet B.
g / cm, the feed tension of the support is 600 g / cm, the total load is 3.0 tons, the upper roll temperature is 60 ° C, the lower roll temperature is 90 ° C, and the feed speed is 3.0 m / min. The laminate (laminate of the support, the phosphor layer sheet A, and the phosphor layer sheet B) was wound at a tension of 400 g / cm. The tension of the phosphor layer sheet B was controlled so as to be in a range of ± 10% by feedback of a signal from a tension pickup roll. By this heat compression treatment, a laminated phosphor layer (layer thickness: 305) in which the phosphor layer sheets A and B are sufficiently adhered.
μm) was completely fused onto the support via the conductive layer.

Preparation of Surface Protective Layer The same procedure as in the preparation of the surface protective layer on a 6 μm-thick PET film (“Lumirror 6C-F53” manufactured by Toray Industries, Inc.). Under the following conditions, coating and drying were carried out, and a surface protective layer having a thickness of 2 μm was provided on the PET film, and then on the surface of the support opposite to the side on which the coating layer was provided, Apply an unsaturated polyester resin solution (“Vylon 30SS”; Toyobo Co., Ltd.),
A dry, adhesive layer was formed. The adhesive was applied so that the coating weight of the adhesive contained in the solution was 2 g / m ² . The laminate of the adhesive layer, the PET film, and the surface protective layer thus produced was bonded on the phosphor layer by a laminating roll. (The phosphor layer and the adhesive layer were brought into contact with each other and bonded by the laminating roll. .). Thus, a protective layer (a laminate of a PET film and a surface protective layer) having a thickness (8 μm) was formed on the phosphor layer.

Embossing The surface of the surface protective layer was embossed under the following conditions.
The embossing is performed using a chrome material having a diameter of 20 cm, an average surface roughness Ra of the surface = 2.4 μm, and an average maximum height Rt of the surface.
m = 19.8 μm embossing roll, linear pressure 40 k
At g / cm and a roll temperature of 50 ° C., an uneven pattern was transferred to the sheet surface, and the average surface roughness Ra (surface of the surface protective layer) was set to 0.20 μm. Thus, the average surface roughness Ra of the front surface is 0.20 μm, and the average surface roughness Ra of the back surface is Ra.
= 0.14 µm double-sided condensing reading radiation image conversion panel 1 (Example 2) was obtained.

In the method for producing the radiation image conversion panel 1 for double-sided condensing reading, the organic filler used for preparing the coating solution for the backside protective layer of the support was replaced by “Eposter S6”.
(Nippon Shokubai Co., Ltd .; melamine-formaldehyde resin; average particle size: 0.6 μm) In the same manner, the average surface roughness Ra of the front surface was 0.20 μm, and the average surface roughness of the back surface was Ra = A 0.06 μm double-sided condensing reading radiation image conversion panel 2 (Comparative Example 2) was obtained.

The obtained radiation image conversion panels 1 and 2 for double-sided condensing reading were evaluated as follows.
The front and back surfaces of each of the radiation image conversion panels produced as described above were scratched at a speed of 1 cm / sec using a diamond needle having a tip radius of curvature of 0.1 mm. At this time, the load applied to the radiation image conversion panel is 0 to 100.
g. Thereafter, the radiation image conversion panel is irradiated with X-rays having a tube voltage of 80 kVp and 10 mR to form an accumulated image of radiation energy. Then, a laser beam having a wavelength of 680 nm is scanned, and the stimulable phosphor in the phosphor layer is scanned. Was excited to emit stimulable fluorescence. The stimulable light emitted from the phosphor layer was condensed from the front surface and the back surface, respectively, converted into an electric signal, and reproduced as an image by an image reproducing device on a display device.

With respect to the image quality of the reproduced image and the visibility of the scratches on the surface of the panel, the front and rear surfaces of the panel were each evaluated on a five-point scale in the same manner as described above. A rating of 3 or more was considered acceptable for practical use. In addition, from the results of both evaluations, a comprehensive judgment was made on the practicality of the radiation image conversion panel for double-sided condensing reading. Table 2 shows the evaluation results. In addition, about the comprehensive evaluation of Table 2, the meaning of "(circle)" and "x" is as follows. ：: Practically sufficient characteristics as a radiation image conversion panel for double-sided condensing reading. ×: Practically inferior as a radiation image conversion panel for double-sided condensing reading.

[0055]

[Table 2]

[0056]

According to the present invention, a radiation image conversion panel having high scratch resistance can be provided without deteriorating the quality of a formed image.

[Brief description of the drawings]

FIG. 1 is an example of a cross-sectional view of a radiation image conversion panel of the present invention.

FIG. 2 is another example of a cross-sectional view of the radiation image conversion panel of the present invention.

[Explanation of symbols]

 10 20 Radiation image conversion panel 11 21 Support 12 22 Phosphor layer 13 23 Protective layer

Claims (3)

[Claims] 1. A phosphor layer containing a stimulable phosphor on a support, and a protective layer thereon. The average surface roughness Ra of the surface satisfies the following relational expression. A radiation image conversion panel characterized by the above-mentioned. 0.10 μm ≦ Ra ≦ 0.45 μm 2. A phosphor layer containing a stimulable phosphor on a transparent support, and a protective layer on the phosphor layer, and stimulable luminescent light is condensed from at least the back surface of the support. A radiation image conversion panel for use in a radiation image conversion method, wherein the average surface roughness Ra of the back surface satisfies the following relational expression. 0.10 μm ≦ Ra ≦ 0.45 μm 3. The radiation image conversion panel according to claim 1, wherein the protective layer has a thickness of 5 μm or more and 20 μm or less.