JPS5938700A - Radiation intensifying screen and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation intensifying screen and a method for manufacturing the same. More specifically, the present invention includes a support, a phosphor-containing resin layer provided on the support, and a composition ratio of the binder to the phosphor in the range of 25 to 1:100. The present invention relates to a radiation intensifying screen having substantially no radiation intensifying screen and a method for manufacturing the same.

Radiation intensifying screens increase the sensitivity of imaging systems in various fields of radiography, such as medical radiography such as X-ray photography for medical diagnosis, and industrial radiography for non-destructive testing of materials. In order to improve the quality of the film, it is used by stacking it closely on one or both sides of a radiographic film such as an X-ray film. This radiation intensifying screen basically consists of a support and a phosphor-containing resin layer formed on one side of the support. Note that a transparent protective film is generally provided on the surface of this phosphor-containing resin layer opposite to the support (the surface not facing the support), and the phosphor layer is protected from chemicals. Protects against alteration or physical 111i attack.

The phosphor-containing resin layer is made of a binder that contains and supports phosphor particles in a dispersed state. The phosphor-containing resin layer is generally attached to the support using a coating method under normal pressure as described below.

That is, a coating solution is prepared by mixing and dispersing phosphor particles and a binder in a suitable solvent, and this coating solution is exposed to radiation under normal pressure using a coating means such as a doctor play IS, a roll coater, or a knife coater. After applying the support of the intensifying screen directly to the temple body, the solvent is removed from the coating film, or the coating solution is applied in advance to a temporary support such as glass 4jy under normal pressure, and then the coating film is coated. The solvent is removed from the phosphor-containing resin R film to form a phosphor-containing resin R film, and this is peeled off from the temporary support and bonded to the support of the radiation intensifying screen, thereby transferring the phosphor-containing resin layer onto the support. A thin membrane is being applied.

The phosphor particles in the phosphor-containing resin layer have the property of emitting light at a high temperature of 111 degrees when excited by radiation such as X-rays. Therefore, the phosphor emits high-intensity light depending on the amount of radiation that passes through the subject, and the radiographic film placed overlappingly in contact with the surface of the phosphor-containing resin layer of the radiation intensifying screen Since sensitization is also caused by the emission of this phosphor, sufficient sensitization of the photographic film can be achieved with a relatively small amount of radiation.

It is desired that a radiation intensifying screen having the basic structure as described above has high sensitivity and provides images with good image quality (sharpness, granularity, etc.). Among these, in terms of image sharpness, it is desirable to develop a radiation intensifying screen that improves the sharpness of the image even slightly, since it can obtain more accurate and detailed information about the subject. There is.

An object of the present invention is to provide a radiation intensifying screen that provides images with improved sharpness and a method for manufacturing the same.

The purpose of the two-legged support is that the composition ratio of the binder and the phosphor provided on the support is 1=25 to 1:100 (
In a radiation intensifying screen substantially composed of a phosphor-containing resin layer with a weight ratio of This can be achieved by the radiation intensifying screen of the present invention, which has a porosity of 90% or less of the porosity of the phosphor-containing resin layer having the composition ratio.

In addition, the above object is as follows: (1) The composition ratio of the binder and the phosphor formed by the coating method under normal pressure between the support and the passage provided in the support -L is 1=25 to lg1oo( By compressing a sheet that is substantially composed of a phosphor-containing resin layer with a phosphor content of 1 liter, the porosity of the phosphor-containing resin layer is reduced to 90% of the porosity before the compression treatment. A method for producing a radiation intensifying screen of the present invention, which is characterized by the following:
Alternatively, (2) a phosphor-containing resin layer formed by a normal coating method under normal pressure and having a composition ratio of binder and phosphor in the range of 1:25 to 1:100 (weight ratio) is compressed. After the porosity of the phosphor-containing resin layer is set to 90% or less of the porosity before compression treatment, the phosphor-containing resin layer is formed into a thin film on a support. One major step in producing the radiation intensifying screen of the present invention can be achieved by:

Next, the present invention will be explained in detail.

In the present invention, the composition ratio of the binder and the phosphor is 1:25 to 1:
The porosity of the phosphor-containing resin layer of the radiation intensifying screen in the range of 100 (weight ratio) is higher than the porosity of the phosphor-containing resin layer of the composition ratio formed by a normal coating method under normal pressure. By reducing it below a certain level,
This invention realizes a remarkable improvement in the sharpness of the radiation-sensitizing screen, that is, a remarkable improvement in the sharpness of images formed and recorded on radiographic film when the radiation-sensitizing screen is used.

That is, when forming a phosphor-containing resin layer (hereinafter simply referred to as the phosphor layer) consisting of a phosphor and a binder on a support using a normal coating method under normal pressure, air is trapped in the phosphor layer. It is easy to get mixed in, creating voids. This void is particularly likely to occur around the phosphor particles. Further, as the content of the phosphor in the binder increases, the phosphor particles become denser, and a large number of voids tend to occur between the phosphor particles.

By the way, when radiation such as X-rays that has passed through the subject enters the phosphor layer of the radiation-sensitizing screen, the phosphor particles in the phosphor layer absorb radiation energy corresponding to the transmitted image and become excited. , instantaneously emits light in the visible to near ultraviolet range that has a wavelength different from that of the radiation. The light emitted from the phosphor particles sensitizes the photographic film and contributes to image formation. Generally, as the amount of phosphor contained in the phosphor layer increases, the amount of light emitted increases, and therefore the sensitivity improves. On the other hand, sharpness depends on the thickness of the phosphor layer. In other words, the thicker the phosphor layer, the more the light emitted from the phosphor particles is diffused in the phosphor layer, and the more blurred the light image is recorded on the photographic film, the more the resulting image becomes Sharpness decreases. Therefore, by making the phosphor layer thinner, images with improved sharpness can be obtained.

According to the studies of the present inventors, a radiation enhancer substantially composed of a phosphor-containing resin layer in which the M1 composition ratio of the binder and the phosphor is in the range of 1:25 to 1:100 (weight ratio). In the sensitive screen, by setting the porosity of the phosphor layer to 90% or less of the porosity of the phosphor-containing resin layer of the composition ratio formed by the usual coating method under normal pressure, the porosity of the phosphor layer is reduced. The density of the phosphor can be made higher than the density of the phosphor in conventional radiation-sensitizing screens, and as a result the thickness of the phosphor layer can be reduced, significantly improving the sharpness of the image. There was found.

Furthermore, since the radiation-sensitizing screen of the present invention has a phosphor layer with a higher concentration of phosphor than the density of phosphor in the phosphor layer of a conventional radiation-sensitizing screen, for example,
If the phosphor layer of the radiation-sensitizing screen of the present invention has the same layer thickness as the phosphor layer of the conventional radiation-sensitizing screen, the phosphor layer of the radiation-sensitizing screen of the present invention has a larger thickness. The radiation intensifying screen of the present invention, which can contain phosphor particles, can therefore improve sensitivity without reducing sharpness. That is, in the same sharpness comparison, the radiation intensifying screen of the present invention has higher sensitivity than the conventional radiation intensifying screen. Conversely, when comparing the same sensitivity, the radiation intensifying screen of the present invention has higher sharpness than the conventional radiation intensifying screen.

Furthermore, by coloring the protective film or phosphor layer, the radiation-sensitizing screen of the present invention has the same sensitivity and sharpness as conventional radiation-sensitizing screens. is good.

The radiation sensitizing screen of the present invention having the preferable characteristics as described above can be manufactured, for example, by the method described below.

In the radiation intensifying screen of the present invention, the phosphor-containing resin layer is basically a layer made of a binder containing and supporting phosphor particles in a dispersed form.

Various kinds of quencher particles are already known. Examples of radiation-sensitizing phosphor particles preferably used in the present invention include particles made of the following substances.

Tungstate-based phosphors (CaWO4, MgWO4,
CaWO4: Pb, etc.), terbium activated 17 J: oxysulfide-based phosphor [Y 202 S: T b, G d
202S: Tb, La 202S:
T b, (Y, Gd) 202S: Tb, (Y, G
d) 202S・T b , T m, etc.], Tiruvira 1-activated rare earth phosphate-based I 11-photon substance (Y P O4: T b
, G d P Oa: T b, L a P O
a: Tb, etc.), terbium-activated rare earth oxyhalide phosphor (LaOBr: Tb.

La0Br: Tb, Tm, La0CJl: Tb, Lao
Sentence c: T b , Tm, G dOB'r : T
b, Gd0Cl: Tb, etc.), thulium-activated earth oxyhalide phosphor (L aOB r: T
m, La0Cl: Tm, etc.), barium sulfate-based phosphor [BaSO4: Pb, BaSO4:Eu'', (Ba,
S r) SOa: E u2+ etc.], divalent noeurobium activated alkaline earth metal phosphate phosphor [B11
L3(po4)2: E u24, (Ba,
Sr) 3 (POa)2:Eu2+ etc.], divalent europium activated alkaline earth metal fluorohalide phosphor [BaFCJl:Eu”, BaFBr:Eu”, Ba
FCI:Eu”, Tb, BaFBr:Eu”.

Tb, BaF2*BaCM2mKCM:Eu”, BaF
2 *BaCJlj 2 *xBaSO4eKc
u:Eu”, (Ba, Mg)F2.*BaCM2 e
KCu:Eu2+, etc.], iodide-based phosphors (CsI:Na
, CsI:Tn, NaI, KI:TJlj, etc.), sulfide-based phosphors [ZnS:Ag, (Zn, Ccl)S:Ag
, (Zn, Cd)S: Cu, (Zn.

Cd) S: Cu, AM, etc.], hafnium phosphate phosphor (Hf P2O7: Cu, etc.). However, the phosphor particles used in the present invention are not limited to these, and may be any phosphor particles that emit light in the visible to near ultraviolet region when irradiated with radiation.

Examples of binders for the phosphor layer include proteins such as gelatin, polysaccharides such as dextran, or natural polymeric substances such as gum arabic; and polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethyl cellulose, and vinylidene chloride.・Vinyl chloride copolymer,
Examples of binders include synthetic polymeric substances such as polymethyl methacrylate, vinyl chloride/vinyl acetate copolymer, polyurethane, cellulose acetate butyrate, polyvinyl alcohol, and linear polyester. Particularly preferred among such binders are nitrocellulose linear polyesters and mixtures of nitrocellulose and linear polyesters.

The phosphor layer can be formed on the support by, for example, the following coating method.

First, the phosphor particles described in "-" and a binder are added to a suitable solvent and mixed thoroughly to prepare a coating solution in which the phosphor particles are uniformly dispersed in the binder solution.

Examples of solvents for preparing coating solutions include lower alcohols such as methanol, ethanol, n-propanol, and n-butanol; chlorine-containing hydrocarbons such as methylene chloride and ethylene chloride; acetone, methyl ethyl ketone, and methyl isobutyl ketone. Ketones; esters of lower fatty acids and lower alcohols such as methyl acetate, ethyl acetate, and butyl acetate; ethers such as dioxane, ethylene glycol monoethyl ether, and ethylene glycol monomethyl ether; and mixtures thereof.

The composition ratio of the binder and the radiation-sensitizing phosphor particles in the coating solution varies depending on the characteristics of the intended radiation-sensitizing screen, the type of phosphor particles, etc., but is between 1:25 and 1:25.
100 (weight ratio), and especially l:2
It is preferable to select from the range of 5 to 1:85 (weight ratio).

The coating liquid also contains a dispersant to improve the dispersibility of the phosphor particles in the coating liquid, and a dispersant to improve the bonding force between the binder and the phosphor particles in the phosphor layer after formation. Various additives, such as plasticizers, may be mixed to make the material more durable. Examples of dispersants used for such purposes include phthalic acid, stearic acid, caproic acid, lipophilic surfactants, and the like. Examples of plasticizers include phosphate esters such as triphenyl phosphate, tricresyl phosphate, and diphenyl phosphate; diethyl phthalate;
Phthalate esters such as dimethoxyethyl phthalate; glycolic acid esters such as ethyl phthalylethyl glycolate and butylphthalyl butyl glycolate; and
Examples include polyesters of polyethylene glycol and aliphatic dibasic acids, such as polyesters of triethylene glycol and adipic acid, and polyesters of diethylene glycol and succinic acid.

The coating solution containing the phosphor particles and binder prepared as described above is then uniformly applied to the surface of the support to form a coating film of the coating solution. This coating operation can be carried out using conventional coating means, such as a doctor blade, roll coater, knife coater, etc.

The formed coating film is then dried by gradually heating to complete the formation of the phosphor layer on the support. The thickness of the phosphor layer varies depending on the characteristics of the intended radiation intensifying screen, the type of phosphor particles, the mixing ratio of the binder and the phosphor particles, and is usually 20 gm to 1 mm. However, the thickness of this layer is preferably 50 to 500 pm.

Note that the phosphor-containing resin layer does not necessarily need to be formed by directly applying a coating liquid onto the support as described above. After forming a phosphor layer by coating Q 11+ liquid on the support and drying it, it is pressed onto the support or attached to the support and the phosphor layer using an adhesive. The layers may also be bonded together.

In addition, the RLT photon-containing resin layer is coated with a colorant to improve the graininess of the resulting radiation-sensitized screen.
'May be colored.

The support used in the present invention can be arbitrarily selected from various materials known as materials for producing radiation intensifying screens. Examples of such materials include films of plastic materials such as cellulose acetate, polyester, polyethylene terephthalate, polyamide, polyimide, I-reacetate, polycarbonate, metal sheets such as aluminum foil, aluminum alloy foil, and ordinary paper. Examples include baryta paper, resin-coated paper, pigment paper containing pigments such as titanium dioxide, and paper sized with polyvinyl alcohol. However, when considering the characteristics as a radiation intensifying screen, in the present invention, i'+ (lf
A preferred support material is a plastic film. This plastic film may be kneaded with a light-absorbing P1 substance such as carbon blank, or may be kneaded with a light-reflecting substance such as titanium dioxide. The former is a support suitable for a high sharpness type radiation sensitizing screen, and the latter is a support suitable for a high sensitivity type radiation sensitizing screen.

In known radiation-sensitizing screens, gelatin is added to the surface of the support on the side where the phosphor layer is provided, in order to strengthen the bond between the support and the phosphor layer, or to improve the sensitivity or image quality of the radiation-sensitized screen. It is also possible to apply a polymeric substance such as to form an adhesion-imparting layer, or to provide a light-reflecting layer made of a light-reflecting substance such as titanium dioxide, or a light-absorbing layer made of a light-absorbing substance such as carbon black. It is. In addition, in radiation-sensitizing screens used in industrial radiography for the purpose of non-destructive testing of substances, lead foil or lead alloy is used on the surface of the support on the side where the phosphor layer is provided for the purpose of removing scattered radiation. It is also practiced to provide metal foil such as foil or tin foil. The support used in the present invention can also be provided with these various layers.

Furthermore, in order to improve the sharpness of the resulting image, the surface of the support on the phosphor layer side (the surface of the support on the phosphor layer side is coated with an adhesive layer, a light reflection layer, a light absorption layer, or a metal foil). If the radiation sensitizing slurry 2 is provided with an uneven surface, unevenness can be formed on the surface thereof, and the structure thereof can be arbitrarily selected depending on the purpose and use of the desired radiation sensitizing slurry 2. be able to.

The porosity of the phosphor-containing resin layer formed on the support as described in 1- can be theoretically determined by the following formula (I).

Vair/V=V[(atb)/)x/)y-aρyρair b
pxρairl---(I) (where ■ = total volume of the phosphor layer Vair: volume of air in the phosphor layer A: total weight of the phosphor.

p' from,
Formula (I) can be approximately expressed by the following formula (n).

Vair/V= (atb)pxpyV A (apy+ bρ
X) V [(atb)ρXρyl ---(n) (where V, Vair, A, ρx, /)y, at
and b are the same as in formula (I)) In the present invention, the porosity of the phosphor-containing resin layer was determined from the beginning using formula (n).

As an example, the formation of a phosphor-containing resin layer consisting of a terbium-activated gadolinium oxysulfide phosphor and a mixture of linear polyester and nitrocellulose as a binder onto a support may be carried out according to the usual practice described in The coating method is carried out under pressure, and specifically, for example, as follows.

A mixture of linear polyester and nitrocellulose and a terbium-activated sulfide-resistant gadolinium phosphor (Gd202S:
Tb) particles are thoroughly mixed in methyl ethyl ketone using a propeller mixer so that the composition ratio is 1:40 (weight ratio) to prepare a coating liquid with a viscosity of 30 PS (25°C). After uniformly applying this coating liquid onto the polyethylene terephthalate (support) using a doctor blade, place it in a dryer and adjust the temperature inside the dryer from 25°C to l.
By gradually increasing the temperature to oo'c and drying the coating film, a phosphor-containing resin layer is formed on the support.

The porosity of the phosphor-containing resin layer formed in this way, in which the composition ratio of the binder to the phosphor was 1:40, was 32.2%. In addition, the porosity of the phosphor-containing resin layer with a composition ratio of binder and phosphor of 1:80, which was formed in the same manner as above except for changing the amounts of binder and phosphor used, was as follows:
It was 35.0%.

The above phosphor-containing resin layer is a typical example of a phosphor layer formed by a normal coating method under normal pressure, and even if the binder, phosphor particles, and solvent used are changed, the fI
The porosity of the phosphor layer does not change significantly. In addition, in the porosity gtrl of equation (n), the additive added to the coating liquid is a component, so it can be ignored. Furthermore, the porosity of the phosphor layer is not significantly affected by changes in coating conditions as long as it is within the range of commonly practiced coating operations.

Therefore, as is clear from the equation (IF) above, the biggest factor that changes the porosity of the phosphor-containing resin layer is the composition ratio of the binder and the phosphor [from the definition of the equation (■), b: a , weight ratio]. As the ratio of the phosphor particles to the binder increases in the phosphor-containing resin layer, the average distance between the phosphor particles dispersed in the binder becomes shorter and voids are more likely to form between them. Therefore, the porosity of the phosphor-containing resin layer is equal to that of the phosphor! It tends to increase as the number of 11- increases.

In the production of the radiation intensifying screen of Wood's invention, the first step is to reduce voids by removing part of the air mixed in the phosphor layer. This reduction in voids is achieved, for example, by compressing the phosphor layer.

The compression treatment of the phosphor layer is generally 50-1500k
It is carried out at a pressure in the range of g/cm' and while heating at a temperature in the range from room temperature to around the melting point of the phosphor layer. The compression time is preferably in the range of 30 seconds to 5 minutes. Also, the preferred pressure is 300-700 kg/c
m', and the preferable temperature is 50 to 120°C, although it varies depending on the binder used.

Examples of compression devices used for compression treatment of wood products include commonly known devices such as calender rolls and hot presses. For example, compression treatment using calender rolls is carried out by passing a sheet consisting of a support and a phosphor layer at a constant speed between rollers heated to a constant temperature. In addition, compression treatment using a hot press involves fixing the sheet between two metal plates heated to a certain temperature, and then pressing the sheet from both sides.
This is done by applying a certain amount of pressure for a certain amount of time. However, the compression device used in the present invention is not limited to these devices, and any device may be used as long as it can compress the sheet as described above while heating it.

For example, when compressing a phosphor-containing resin thin film formed on a temporary support, it is also possible to carry out the compression treatment before attaching the thin film to the support of the radiation intensifying screen. In that case, a thin phosphor-containing resin film alone or a composite sheet of a phosphor-containing resin thin film and a temporary support is compressed, and then the compressed phosphor-containing resin thin film is sensitized by radiation. 1,000 on the support of the screen.

Note 1: In a normal radiation intensifying screen, a transparent protective film is provided on the surface of the phosphor layer on the side opposite to the side in contact with the support to physically and chemically protect the phosphor layer. There is. It is preferable to provide such a transparent protective film also in the radiation intensifying screen of the present invention.

The transparent protective film can be made of, for example, cellulose derivatives such as cellulose acetate, di-cellulose, or polymethyl methacrylate-1, polyvinyl butyral, polyvinyl formal, polycarbonate, polyvinyl acetate, vinyl chloride/vinyl acetate copolymer, etc. The phosphor layer can be formed by coating the surface of the phosphor layer with a solution prepared by dissolving a transparent polymer material such as a synthetic polymer material in an appropriate solvent. Alternatively, it can also be formed by a method such as adhering a transparent thin film separately formed from polyethylene terephthalate, polyethylene, vinylidene chloride, polyamide, etc. to the surface of the phosphor layer using a suitable adhesive. The thickness of the transparent protective film thus formed is preferably about 3 to 20 ILm.

The transparent protective film may be decolored with a coloring agent in order to improve the graininess of the resulting radiation intensifying screen.

The phosphor-containing resin layer of the radiation intensifying screen of the present invention manufactured by the method typified by the method described in 2 below (composition ratio of binder and phosphor is 1:25 to 1:10)
The porosity of the phosphor-containing resin layer (within the range of 0) is 90% or less of the porosity of the phosphor-containing resin layer of the composition ratio formed by a coating method under normal pressure, and The porosity (absolute value) of the phosphor-containing resin layer generally does not exceed 35%.

As mentioned above, by reducing the porosity of the phosphor-containing resin layer in the radiation intensifying screen, the density of the phosphor in the phosphor layer increases, and therefore, if the amount of IF light used is constant, the phosphor layer becomes thinner. As a result, the sharpness of the image is significantly improved.

Next, Examples and Comparative Examples of the present invention will be described.

However, each of these does not limit the present invention.

[Example 1] A mixture (binder) of a linear polyester resin and dicellulose with a degree of nitrification of 11.5% and a terbium-activated sulfide-resistant gadolinium phosphor (Gd202S:T) for radiation sensitization.
b) particles at a weight-76 composition ratio of 1:40, methyl ethyl ketone was added, and the mixture was thoroughly stirred using a propeller mixer to ensure that the phosphor particles were uniformly dispersed and that the viscosity was 30 PS ( 25°C) was prepared. Next, a polyethylene terephthalate sheet (support, thickness: 250 pm) into which titanium dioxide was kneaded was placed horizontally on a glass plate, and the coating solution was uniformly applied onto this support using a doctor blade. After coating, the support on which the coating film was formed was placed in a dryer, and the temperature inside the dryer was gradually raised from 25°C to 100°C to dry the coating film. . In this way, a sheet was obtained consisting of a support and a fluorescent layer with a layer thickness of about 120 gm provided on the support.

Next, a sheet I consisting of a support and a phosphor layer formed on one side of the support is prepared using a calender roll.
20 kg/cm' pressure, and 100 °C
It was compressed at a temperature of

Then, simply attach a polyethylene terephthalate transparent film (thickness = 12 gm, coated with polyester adhesive) to the compressed phosphor layer with the adhesive layer side facing down. By doing so, a transparent protective film was formed, and a radiation intensifying screen composed of a support, a phosphor layer, and a transparent protective film was manufactured.

[Example 2] The same sheet as the sheet consisting of the support produced in Example 1 and the phosphor layer provided on this support was
A radiation intensifying screen composed of a support, a phosphor layer, and a transparent protective film was prepared by performing the same treatment as in Example 1, except that it was compressed at a pressure of 0 kg/cnf and a temperature of 100°C. was manufactured.

[Example 3] The same sheet as the sheet made of the support produced in Example 1 and the phosphor layer provided on this support was
A fabric consisting of a support, a phosphor layer, and a transparent protective film was prepared by performing the same process as in Example 1 except that it was compressed at a pressure of kg/cm' and a temperature of 100°C. A radiation intensifying screen was manufactured.

[Example 4] The same sheet as the sheet made of the support produced in Example 1 and the phosphor layer provided on this support was
By carrying out the same process as in Example 1, except for compressing at a pressure of kg/cm' and a temperature of 80 °C, a sample composed of a support, a phosphor layer, and a transparent protective film was prepared. A radiation intensifying screen was manufactured.

[Example 5] Sheet I-, which is the same as Sheet I, consisting of the support produced in Example 1 and a phosphor layer provided on this support, was
By carrying out the same process as in Example 1 except for compressing at a pressure of 520 kg/cm' and a temperature of 80 °C, a material consisting of a support, a phosphor layer, and a transparent protective film was prepared. A radiation intensifying screen was manufactured.

[Example 6] The same sheet as the sheet made of the support produced in Example 1 and the phosphor layer provided on this support was
kg/Cm'(7) pressure and a temperature of 80°C, but similar treatment to the method of Example 1 was carried out at 91°C.
In this manner, a radiation-sensitizing screen consisting of a support, a light layer, and a transparent protective film was manufactured.

[Comparative Example 1] The same method as in Example 1 was carried out, except that the same sheet consisting of the support produced in Example 1 and the phosphor layer provided on this support was not compressed. By carrying out the treatment, a radiation intensifying screen consisting of a support, a phosphor layer and a transparent protective film was produced.

The measured values of the volume and weight of the phosphor layer of each radiation intensifying screen produced as described above, the density of the phosphor used (7.5 g/cm') and the density of the binder (
1,258 g/Cm'), the porosity of the phosphor-containing resin layer was calculated and determined using equation (n).

Table 1 shows the results obtained for each phosphor-containing resin layer.

Table 1 Month - 10,000 Temperature Porosity Relative porosity (kg/cm') (°C) (%) (%
) Example 1 B20 100 25.13
78.5 Example 2 520 100 25.7
79.8 Example 3 420 100 26
．． 2 81.4 Example 4' 620 80
2f(,883,2 Example 5 520 80
27.0 83.9 Example 6 420 8o
28.2 87.6 Comparative Example 1 --32.
2 100 Also, the radiation intensifying screens of Example 1 and Comparative Example 1, which were manufactured in a similar manner, were evaluated by the image sharpness test described below. That is, a radiation intensifying screen and an X-ray filter are crimped together in a cassette, an X-ray filter is taken through a resolution chart, and the modulation transfer function (MTF) of the resulting X-ray photograph is determined.
) was measured.

The results of the leakage are summarized and shown in the form of a graph on the drawing.

The drawings are: A: Relationship between spatial frequency and M TF value in the radiation intensifying screen of Example 1, and B: Relationship between spatial frequency and M'r in the radiation intensifying screen of Comparative Example 1.
The relationship with the F value is expressed respectively.

Also, regarding each radiation intensifying screen (!)・
Results (M at spatial frequency 2 cycles/mm
TF value) are shown in Table 2.

Table 2 Sharpness Example 1 0.36 Comparative Example 1 0.32 [Example 7] Mixture (binder) of linear polyester resin and nitrocellulose with a degree of nitrification of 11.5% and terbium for radiation sensitization Activated gadolinium oxysulfide phosphor (Gd202S:Tb
) particles in a heavy lf1 composition ratio of 1:80, but by performing the same treatment as in Example 1, a radioactive material composed of a support, a phosphor layer, and a transparent protective film was prepared. An intensifying screen was manufactured.

[Example 8] A sheet +-, which is the same as the sheet I, consisting of the support produced in Example 7 and the phosphor layer provided on the support, was
By carrying out the same process as in Example 7, except for compressing at a pressure of 20 kg/cm' and a temperature of ioooC, a radioactive material composed of a support, an optical layer, and a transparent protective film was prepared. An intensifying screen was manufactured.

[Example 9] A sheet consisting of the support produced in Example 7 and a phosphor layer immersed in this support was
45 supports 1. were processed in the same manner as in Example 7 except that they were compressed at a pressure of 20 kg/cm' and a temperature of 100°C. )i7. A radiation intensifying screen consisting of a photolayer and a transparent protective film was manufactured.

[Example 10] The same sheet as the sheet consisting of the support produced in Example 7 and the phosphor layer provided on this support was
Pressure of 0 kg / cm' and 80 ° 0 (7)
A radiation intensifying screen consisting of a support, a phosphor layer, and a transparent protective film was produced by performing the same treatment as in Example 7, except for compressing at a temperature.

[Example 11] The same sheet i as the sheet consisting of the support produced in Example 7 and the phosphor layer provided on this support was
The support, phosphor layer, and transparent protective film were separated by a similar process to that of Example 7, except that they were compressed at a force of 20 kg/cm' and a temperature of 80°C. A constructed radiosensitizing screen was manufactured.

[Example 12] The same sheet as the sheet made of the support produced in Example 7 and the phosphor layer provided on this support was
kg/cm'c 7) Pressure and temperature of 80 °C, but by performing the same treatment as the method of Example 7, a material composed of a support, a phosphor layer, and a transparent protective film was prepared. A radiation intensifying screen was manufactured.

[Comparative Example 2] The same method as in Example 7 was carried out, except that the same sheet as the sheet consisting of the support produced in Example 7 and the phosphor layer provided on this support was not compressed. By carrying out the treatment, a radiation-sensitizing screen consisting of a support, an optical layer, and a transparent protective film was manufactured.

The porosity of the phosphor-containing resin layer of each radiation intensifying screen manufactured as described in Section 16 was determined by calculation using the same method as described above.

Table 3 shows the results obtained for each phosphor-containing resin layer.

Table 3 Pressure Temperature Porosity Relative porosity (kg/Cm') (''C) (%) (%
) Example 7 B20 100 29.0
82.9 Example 8 520 100 29.3
83.7 Example 9 420 100 2B, 8
85.1 Example 10 620 80 30.
4 81 (, 11 Example 11 520 80
30.7 87.7 Example 12 420 80
31.2 89.1 Comparative Example 2 - -
35.0 100 Furthermore, the radiation intensifying screens of Example 7 and Comparative Example 2 produced as described above were evaluated by the above-mentioned image sensitization test.

For each radiosensitizing screen, the results obtained (
MTF i1r at spatial frequency 2 cycles/mm
1) is shown in Table 4.

Table 4 sharpness Example 7 0.40 Comparative example 2 0.35

[Brief explanation of drawings]

The drawing is a graph of the modulation transfer function (MTF) of X-ray photographs obtained using the radiation intensifying screens manufactured in Example 1 and Comparative Example 1. In the drawings, A represents the spatial frequency and MTF itr of the radiation intensifying screen of Example 1 (the radiation intensifying screen of the present invention).
and B respectively represent the relationship between the spatial frequency and the MTF value in the radiation intensifying screen of Comparative Example 1 (the radiation intensifying screen manufactured by the coating method of Tsu'hata). Patent applicant Fuji Photo Film Co., Ltd. Agent Patent attorney Yasuo Yanagawa

Claims (1)

[Claims] l. The composition ratio of the support, the binder provided on the support, and the phosphor is 1=25 to 1:100 (weight ratio)
In the radiation intensifying screen, the porosity of the phosphor-containing resin layer is within the range of the composition ratio formed by a normal coating method under normal pressure. A radiation-sensitizing screen characterized by having a porosity of 90% or less of the porosity of the phosphor-containing resin layer. 2. The radiation intensifying screen according to claim 1, wherein the phosphor is a terbium-activated sulfide-resistant gadolinium phosphor. 63. The binder is a mixture of linear polyester and nitrocellulose. A radiation intensifying screen according to claim 1 or 2, characterized in that: 4. Claims 1 to 3, characterized in that the porosity of the phosphor-containing resin layer is reduced by subjecting the phosphor-containing resin layer to compression treatment. The radiosensitizing screen described in any of the above. A 5° support and a binder formed on this support by a normal coating method under normal pressure and a phosphor having a composition ratio in the range of 1:25 to 1:100 (weight ratio). A radiation source characterized in that the porosity of the phosphor-containing resin layer is reduced to 90% or less of the porosity before the compression treatment by compressing a sheet substantially composed of a phosphor-containing resin layer. Method of manufacturing an intensifying screen. 6. The radiation intensifying screen according to claim 5, wherein the compression treatment is carried out at a pressure of 50 to 1500 kg/cm' and at a temperature above room temperature and below the melting point of the binder. Manufacturing method. 7. The method for producing a radiation intensifying screen according to claim 5, wherein the compression treatment is carried out at a pressure of 300 to 700 kg/cm' and a temperature of 50 to 120°C. 8. A method for producing a radiation intensifying screen according to any one of claims 5 to 7, characterized in that the 8° bipedal compression treatment is carried out using calender rolls. 9. The method for producing a radiation intensifying screen according to any one of claims 5 to 7, characterized in that the compression treatment is performed using a hot press. 10. The method for producing a radiation intensifying screen according to any one of claims 5 to 9, wherein the JZ phosphor is a terbium activation sulfide-resistant gadolinium phosphor. 11. The radiation sensitization according to any one of claims 5 to 10, characterized in that the binder is a compound of linear polyester and nitrocellulose. Screen manufacturing method. 12゜By compressing a phosphor-containing resin layer formed by a normal coating method under normal pressure and having a composition ratio of binder and phosphor in the range of 1:25 to 1:100 (weight ratio), A radiation intensifying screen characterized in that after the porosity of the phosphor-containing resin layer is set to 90% or less of the porosity before compression treatment, the phosphor-containing resin layer is disposed on a support. Manufacturing method. 13゜-I] compression treatment at 50 to 1500 kg/c
13. The method for producing a radiation intensifying screen according to claim 12, characterized in that the process is carried out at a pressure of m' and at a temperature above room temperature and below the melting point of the bipedal binder. 14. The radiation intensifying screen according to claim 12, item 4, wherein the compression treatment is carried out at a pressure of 300 to 700 kg/cm and a temperature of 50 to 120°C. Manufacturing method. 15. The method for producing a radiation intensifying screen according to any one of claims Pf'S12 to 14, characterized in that the compression treatment is carried out using a calender roll. 16゜Claims 12JJ'i to 14th characterized in that the compression process is performed using a hot press.
A method for producing a radiation-sensitizing screen according to any one of paragraphs. 17゜Claim S12, wherein the phosphor is a terbium activation-resistant gadolinium sulfide phosphor.
A method for producing a radiation intensifying screen according to any one of Items 1 to 16. A method for producing a radiation intensifying screen according to any one of claims 12 to 17, characterized in that the 18°" bipedal binder is a mixture of linear polyester and nitrocellulose. .