JP2005156491A - Manufacturing method for radiation image conversion panel and radiation image conversion panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for radiation image conversion panel of which the granularity and sharpness are improved and image defects are reduced. <P>SOLUTION: In the manufacturing method for the radiation image conversion panel, in which a stimulable phosphor layer is formed on the base plate with gas-phase deposition, its film forming device has an exhaust means for setting an evaporation chamber at a vacuum state, and a vacuum meter for measuring vacuum degree. The evaporation chamber has a base plate arranging means and stuff evaporation means for depositing a stuff with stimulable phosphor on the base plate. The evaporation chamber is depressurized from the atmospheric pressure to a vacuum state, and before the deposition process depositing the stuff to the base plate by evaporating, the evaporation chamber is set at a vacuum degree P<SB>2</SB>higher than the vacuum degree P<SB>1</SB>set in the depositing process. In the manufacturing method, the chamber is set at a base plate temperature T<SB>2</SB>which is higher than the base plate temperature T<SB>1</SB>set in the depositing process and maintained for a certain period. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is used to obtain image information by using stimulated luminescence by scanning a stimulable phosphor with excitation light after storing and storing a radiation image such as X-rays in the stimulable phosphor. More particularly, the present invention relates to a radiation image conversion panel having a photostimulable phosphor formed on a substrate by a vapor deposition method and a method for manufacturing the same.

  Conventionally, so-called radiography using a silver salt has been used to obtain a radiographic image, but a method for imaging a radiographic image without using a silver salt has been developed. That is, the radiation transmitted through the subject is absorbed by the phosphor, and then the phosphor is excited with a certain energy to emit the radiation energy accumulated in the phosphor as fluorescence, and this fluorescence is detected. A method for imaging is disclosed.

  As the above image forming method, for example, radiation image conversion in which a stimulable phosphor layer is formed on a substrate as disclosed in US Pat. No. 3,859,527 and JP-A-55-12144. The panel is used. This radiation image conversion panel applies radiation transmitted through the object to the photostimulable phosphor layer and accumulates radiation energy corresponding to the radiation transmittance of each part of the object in the stimulable phosphor layer to form a latent image (accumulated image). Form. Next, the photostimulable phosphor layer is scanned with stimulated excitation light (laser light is used) to radiate the radiation energy accumulated in each part to convert it into light, and the intensity of the light is read. This is a method for obtaining an image. This image may be reproduced on various displays such as a CRT, or may be reproduced as a hard copy.

  This radiation image conversion panel has a dispersion type phosphor layer formed by a method of applying and drying a liquid in which phosphor particles are dispersed in a binder resin solution on a substrate, and vapor deposition on the substrate. Some of them have a vapor-deposited phosphor layer formed by the method, and the characteristics required for any radiation image conversion panel are sensitivity to radiation and graininess and sharpness of the formed image.

  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 sensitivity to radiation, it is necessary to increase the thickness of the photostimulable phosphor layer. However, if the thickness is too large, the photostimulable luminescence is scattered between photostimulable phosphor particles. There is a phenomenon that light emission does not come out, and there is a limit naturally. The sharpness is improved as the stimulable phosphor layer is made thinner. However, if the stimulable phosphor layer is too thin, the sensitivity decreases greatly.

  Further, the granularity of the image is determined by the local fluctuation (quantum mottle) of the radiation quantum number or the structural disorder (structural mottle) of the stimulable phosphor layer of the radiographic image conversion panel. When the thickness of the photostimulable phosphor layer is reduced, the number of radiation quantum absorbed in the photostimulable phosphor layer decreases and the quantum mottle increases, or structural disturbance becomes obvious and the structure mottle increases. The image quality is degraded. Therefore, in order to improve the image granularity, the stimulable phosphor layer needs to be thick.

  The vapor deposition type phosphor layer is 100% phosphor compared to the dispersion type phosphor layer. Therefore, when the phosphor is the same, the sensitivity is excellent at the same layer thickness, and the relative radiation absorption rate is high. In addition, a radiation image conversion panel with a reduced quantum motor and excellent graininess can be achieved. If the sensitivity is the same, the layer thickness can be reduced, and the diffusion of radiation and excitation light within the layer thickness is reduced. Although it should be possible to obtain a radiation image conversion panel with excellent sharpness, it is easy to provide a radiation image conversion panel with excellent sensitivity as described above, but both graininess and sharpness are excellent. Presently, providing a radiographic image conversion panel has a great technical obstacle.

  Thus, the image quality and sensitivity of the radiographic image conversion method using the radiographic image conversion panel are determined from various factors. In order to improve sensitivity and image quality by adjusting a plurality of factors related to sensitivity and image quality, various vapor deposition methods have been studied.

  Usually, a base material and raw materials are prepared in a vapor deposition chamber in an atmospheric pressure state, and the room air is evacuated by a vacuum pump or the like to form a vacuum state. At this time, a method of introducing an inert gas such as Ar gas as an atmospheric gas is used. Furthermore, in the case of performing material deposition while heating the substrate, a method of performing material deposition on the substrate after heating the substrate has been proposed (for example, see Patent Document 1). In this method, it is only necessary to reach the degree of vacuum when the material is deposited on the substrate and the substrate temperature, and after any measurement value reaches the predetermined value, the material is deposited on the substrate immediately. There is a problem that the performance of the obtained radiation image conversion panel cannot be pulled out sufficiently.

  Further, Patent Document 1 discloses a method of gradually cooling a substrate by gradually reducing the output of the heater after forming a vapor deposition film while heating the substrate with a heater. However, in the method proposed in Patent Document 1, after the heating of the substrate is stopped, it is necessary to forcibly lower the natural cooling rate of the substrate or to intentionally control the cooling rate of the substrate. Although effective in some cases, it is generally necessary to cool the substrate at the natural cooling rate of the substrate, while in the course of cooling the substrate, the degree of vacuum is maintained in order to maintain the film quality. It is also desirable to change the substrate temperature and the degree of vacuum at the time of raw material deposition, and it is effective to lead to normal temperature and normal pressure at intervals, without abrupt change. There is no disclosure.

  In addition, in order to obtain the desired image quality and film quality, it is common to set an optimum degree of vacuum in accordance with the purpose of raw material deposition on the substrate. For example, a technique is disclosed in which when a plurality of different vapor deposition materials are vapor-deposited on the film formation surface of the substrate, one vapor deposition material of the different vapor deposition materials is vapor-deposited with its own degree of vacuum (for example, , See Patent Document 2).

  The method described in Patent Document 2 is a case where the raw materials to be deposited on the base material are different, and it is natural that the degree of vacuum is changed with different raw materials, and the raw material is evaporated and deposited on the base material. As in the present invention, there is no mention or suggestion regarding a method for achieving the optimum condition by appropriately changing the degree of vacuum when depositing the raw material on the base material with the same raw material.

  In addition, a material supply device that supplies a film forming material to a predetermined evaporation position is disclosed (for example, see Patent Document 3). In this Patent Document 3, a method of moving a film forming material to a predetermined evaporation position by moving a film forming material in a turret capable of rotating the film forming material and moving the film forming material loaded in the turret in the extending direction of the rotation shaft of the turret. It is. In this method, there is only one evaporation position, which is different from the case where raw material evaporation is performed from a plurality of raw material evaporation means. As in the present invention, in the case of performing raw material evaporation from a plurality of raw material evaporation means, there is no mention or suggestion regarding the technology for preliminarily heating and holding the evaporation source to be evaporated next. .

Under such circumstances, the thickness of the stimulable phosphor layer is reduced, and the diffusion of radiation and excitation light within the stimulable phosphor layer thickness is reduced, resulting in a radiation image with excellent granularity and sharpness. Development of a radiation image conversion panel that can be stably manufactured by a vapor deposition method and a radiation image conversion panel that is manufactured by a method of manufacturing a radiation image conversion panel is desired.
JP 2002-104946 A JP-A-6-172998 JP 2003-247061 A

  The present invention has been made in view of the above problems, and an object thereof is to provide a radiation image conversion panel having improved graininess and sharpness and reduced image defects, and a method for manufacturing the same.

The above object of the present invention is achieved by the following configurations.
(Claim 1)
In a method for producing a radiation image conversion panel in which at least one photostimulable phosphor layer is formed on a substrate using a film forming apparatus for depositing a raw material by a vapor deposition method,
The film forming apparatus includes an evacuation unit that depressurizes the vapor deposition chamber with an evacuation unit and makes a vacuum state, and a vacuum gauge that measures the degree of vacuum in the vapor deposition chamber,
The vapor deposition chamber has a base material placement means and a raw material evaporation means for depositing a raw material mainly composed of a stimulable phosphor on the surface of the placed base material,
The vapor deposition chamber has a substrate heating means, a substrate temperature measurement or a substrate temperature estimation means,
Prior to the deposition process in which the deposition chamber is depressurized from atmospheric pressure to a vacuum state, and the raw material is evaporated and deposited on the substrate, a vacuum higher than the degree of vacuum P ₁ set in the deposition process. degrees is set to P _2, and the radiation image conversion panel manufacturing method characterized by and set to a higher substrate temperature T ₂ than the base material temperatures T ₁ to be set in the deposition process holding a certain time.
(Claim 2)
The radiation image conversion panel manufacturing method according to claim 1, wherein the vacuum chamber P ₂ and the substrate temperature T ₂ are simultaneously heated for a predetermined time before the deposition process, and the wall surface of the vapor deposition chamber is simultaneously heated. Method.
(Claim 3)
In a method for producing a radiation image conversion panel in which at least one photostimulable phosphor layer is formed on a substrate using a film forming apparatus for depositing a raw material by a vapor deposition method,
The film forming apparatus includes an evacuation unit that depressurizes the vapor deposition chamber with an evacuation unit and makes a vacuum state, and a vacuum gauge that measures the degree of vacuum in the vapor deposition chamber,
The vapor deposition chamber has a base material placement means and a raw material evaporation means for depositing a raw material mainly composed of a stimulable phosphor on the surface of the placed base material,
The vapor deposition chamber has a substrate heating means and a substrate temperature measurement or substrate temperature estimation means, and is set in the deposition process after the deposition process in which all the raw materials are evaporated and deposited on the substrate. The radiation is characterized in that it is set to a vacuum level P ₃ lower than the vacuum level P ₁ to be set, and is set to a base material temperature T ₃ lower than the base material temperature T ₁ set in the deposition process and held for a certain period of time. Image conversion panel manufacturing method.
(Claim 4)
In a method for producing a radiation image conversion panel in which at least one photostimulable phosphor layer is formed on a substrate using a film forming apparatus for depositing a raw material by a vapor deposition method,
The film forming apparatus includes an evacuation unit that depressurizes the vapor deposition chamber with an evacuation unit and makes a vacuum state, and a vacuum gauge that measures the degree of vacuum in the vapor deposition chamber,
The vapor deposition chamber has a base material placement means and a raw material evaporation means used in a deposition process for depositing a raw material mainly composed of a stimulable phosphor on the surface of the placed base material. A method of manufacturing a radiation image conversion panel, wherein the degree of vacuum P ₁ is changed according to elapsed time in a deposition process of depositing on a material.
(Claim 5)
A plurality of the raw material evaporation means are provided, and when the raw material evaporation means are sequentially evaporated in an arbitrary combination and deposited on the substrate, the degree of vacuum P ₁ is changed for each evaporation of the raw materials. The method for producing a radiation image conversion panel according to claim 4.
(Claim 6)
6. The radiation image conversion panel manufacturing method according to claim 4, wherein the vacuum degree P ₁ to be changed at each of the elapsed time or the evaporation of the raw material is lowest in the initial vacuum degree and then increased in the vacuum degree. Method.
(Claim 7)
The radiographic image according to claim 6, wherein the vacuum degree in the deposition process of depositing on the base material is changed from low vacuum to high vacuum, then returned to low vacuum, and again set to high vacuum. Conversion panel manufacturing method.
(Claim 8)
In a method for producing a radiation image conversion panel in which at least one photostimulable phosphor layer is formed on a substrate using a film forming apparatus for depositing a raw material by a vapor deposition method,
The film forming apparatus includes an evacuation unit that depressurizes the vapor deposition chamber with an evacuation unit and makes a vacuum state, and a vacuum gauge that measures the degree of vacuum in the vapor deposition chamber,
The vapor deposition chamber has a base material placement means and a raw material evaporation means for depositing a raw material mainly composed of a stimulable phosphor on the surface of the placed base material,
A plurality of the raw material evaporation means, and when the raw material evaporation means are sequentially evaporated in any combination and deposited on the base material, the raw material evaporation means to be evaporated next is a range in which the raw material does not evaporate in advance. A method of manufacturing a radiation image conversion panel, wherein the preheating is carried out and held.
(Claim 9)
It is a radiographic image conversion panel manufactured by the radiographic image conversion panel manufacturing method of any one of Claims 1-8, Comprising: It is contained in the at least 1 layer of photostimulable phosphor layer formed on the base material Radiation image conversion panel, wherein the stimulable phosphor has columnar crystals.
(Claim 10)
The radiation image conversion panel according to claim 9, wherein the main component of the columnar crystal is a stimulable phosphor represented by the following general formula (1).

General formula (1)
CsX: A
[Wherein, X represents Br or I, and A represents Eu, In, Tb or Cs. ]

  According to the present invention, it is possible to provide a radiation image conversion panel with improved graininess and sharpness and reduced image defects and a method for manufacturing the same.

  Hereinafter, the best mode for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

The radiation image conversion panel manufacturing method of the present invention is a radiation image conversion panel manufacturing method in which at least one photostimulable phosphor layer is formed on a substrate using a film forming apparatus for depositing a raw material by a vapor deposition method. The film forming apparatus includes an evacuation unit that depressurizes the vapor deposition chamber with an evacuation unit to make a vacuum state, and a vacuum gauge that measures a degree of vacuum in the vapor deposition chamber, And a raw material evaporation means for depositing a raw material mainly composed of a stimulable phosphor on the surface of the arranged base material,
In the first invention, the vapor deposition chamber has a substrate heating means and a substrate temperature measurement or a substrate temperature estimation means. The vapor deposition chamber is depressurized from the atmospheric pressure to a vacuum state, and the raw material is evaporated. Before the deposition process for depositing on the substrate, the vapor deposition chamber is set to a vacuum degree P ₂ higher than the vacuum degree P ₁ set in the deposition process, and higher than the substrate temperature T ₁ set in the deposition process. The material temperature T ₂ is set and held for a predetermined time.

In the second invention, the vapor deposition chamber has a substrate heating means and a substrate temperature measurement or substrate temperature estimation means, and after the deposition process in which all the raw materials are evaporated and deposited on the substrate. The vacuum degree P ₃ lower than the vacuum degree P ₁ set in the deposition process is set, and the base material temperature T ₃ lower than the base material temperature T ₁ set in the deposition process is set and held for a certain time. Features.

The third aspect of the invention is characterized in that the degree of vacuum P ₁ is changed according to the elapsed time in the deposition process in which the raw material is evaporated and deposited on the substrate.

  In the fourth aspect of the present invention, there are a plurality of raw material evaporation means, and when the raw material evaporation means sequentially evaporates the raw materials in any combination and deposits them on the base material, the raw material evaporation means for performing the next evaporation is previously set as the raw material evaporation means. It is characterized in that it is preheated and held within a range where evaporation does not occur.

  In the present invention, at least one invention selected from the first to fourth inventions described above, or a method for manufacturing a radiation image conversion panel in which a plurality of means are appropriately combined with the first to fourth inventions described above is used. Therefore, it is possible to provide a radiation image conversion panel with improved graininess and sharpness and reduced image defects, and a method for manufacturing the same.

  Details of the present invention will be described below.

  First, the radiation image conversion panel of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an example of the configuration of a photostimulable phosphor layer formed by a vapor deposition method that constitutes the radiation image conversion panel of the present invention.

  In FIG. 1, a photostimulable phosphor layer is formed by forming a photostimulable phosphor layer 12 on a substrate 11 by a vapor deposition method, and further providing a protective layer 13 thereon. In the radiation image conversion panel, this stimulable phosphor plate is fixed on a tray made of carbon fiber reinforced resin (CFRP), glass epoxy resin or the like with an adhesive or the like, and the periphery of the stimulable phosphor plate is bonded. The stimulable phosphor layer is sealed with an agent (not shown).

  FIG. 2 is a schematic view showing an example of a radiation image conversion method using the radiation image conversion panel of the present invention.

  In FIG. 2, 21 is a radiation generator, 22 is a subject, 23 is a radiation image conversion panel of the present invention, 24 is a stimulated excitation light source such as a laser, and 25 is a stimulated fluorescence emitted by the radiation image conversion panel 23. The photoelectric conversion device 26 reproduces the signal detected by the photoelectric conversion device 25 as an image, 27 displays the reproduced image, and 28 separates the stimulated excitation light and the stimulated fluorescence. A filter that transmits only the photostimulated fluorescence. In addition, 25-27 should just be what can reproduce | regenerate the optical information from the radiation image conversion panel 23 as an image in some form, and is not limited above.

  As shown in FIG. 2, the radiation R from the radiation generator 21 is irradiated as incident light RI on the radiation image conversion panel 23 through the subject 22. The incident radiation is absorbed by the photostimulable phosphor layer of the radiation image conversion panel 23, the energy is accumulated, and an accumulated image of a radiographic image is formed.

  Next, this accumulated image is excited by stimulated excitation light from the stimulated excitation light source 24 and emitted as stimulated emission.

  Since the intensity of stimulated emission emitted is proportional to the amount of accumulated radiation energy, this optical signal is photoelectrically converted by a photoelectric conversion device 25 such as a photomultiplier tube and reproduced as an image by the image generation device 26. The radiographic image of the subject can be observed by displaying the image on the image display device 27.

  As the stimulated excitation light source 24, a light source including the stimulated excitation wavelength of the stimulable phosphor used in the radiation image conversion plate is used. In particular, when a laser beam is used, the optical system is simplified, and since the excitation light intensity can be increased, the photostimulative emission efficiency can be increased, and a more preferable result can be obtained.

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 laser, etc. There are metal vapor 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. Further, when using a method of separating light emission using a delay of light emission as shown in Japanese Patent Laid-Open No. 59-22046 without using the filter 28, a pulsed laser is used rather than modulation using a continuous wave laser. It is preferable to use it. 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.

  Next, a method for forming a photostimulable phosphor layer by a vapor deposition method according to the present invention will be described with reference to the drawings.

  Examples of the method for vapor-depositing the photostimulable phosphor on the substrate include vapor deposition, sputtering, and CVD.

In the vapor deposition method, after the base material is installed in the vapor deposition apparatus, the vapor deposition apparatus is evacuated to a vacuum of about 1.3 × 10 ⁻⁴ Pa, and then the stimulable phosphor is subjected to resistance heating, electron beam The photostimulable phosphor is deposited to a desired thickness on the surface of the substrate by heating and evaporating by a method such as a method. As a result, a stimulable phosphor layer composed of the stimulable phosphor alone is formed without containing a binder, but the above-described vapor deposition step is divided into a plurality of times and the stimulable phosphor is divided into a plurality of times. It is also possible to form layers. 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 vapor-deposited using a plurality of resistance heaters or electron beams to synthesize the desired stimulable phosphor on the substrate, and at the same time, the stimulable phosphor. It is also possible to form layers. Furthermore, in the vapor deposition method, the substrate 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.

In the sputtering method, as in the above vapor deposition method, after the base material is placed in the sputtering apparatus, the inside of the sputtering apparatus is once evacuated to a vacuum of about 1.3 × 10 ⁻⁴ Pa, and then as a sputtering gas. An inert gas such as Ar or Ne is introduced into the apparatus to obtain a gas pressure of about 1.3 × 10 ⁻¹ Pa. Next, the photostimulable phosphor is deposited on the surface of the base material with a desired thickness by sputtering using the photostimulable phosphor as a target. In this sputtering process, it is possible to form the photostimulable phosphor layer in a plurality of times in the same manner as the vapor deposition method, and the target is sputtered simultaneously or sequentially using a plurality of photostimulable phosphor materials. It is also possible to form a photostimulable phosphor layer. In the sputtering method, a plurality of photostimulable phosphor materials can be used as targets, and these can be sputtered simultaneously or sequentially to form a desired photostimulable phosphor layer on the substrate. Further, reactive sputtering may be performed by introducing a gas such as O ₂ or H ₂ as necessary. Furthermore, in the sputtering method, the substrate may be cooled or heated as necessary during sputtering. Alternatively, the photostimulable phosphor layer may be heat-treated after the end of sputtering.

  The CVD method does not contain a binder on the base material by decomposing an organometallic compound containing the desired stimulable phosphor or stimulable phosphor raw material with heat, high-frequency power or the like. A stimulable phosphor layer is obtained. In any case, the stimulable phosphor layer can be vapor-phase grown into independent elongated columnar crystals with a specific inclination with respect to the normal direction of the support.

  The thickness of the stimulable phosphor layer formed by these methods varies depending on the radiation sensitivity of the intended radiation image conversion panel, the type of stimulable phosphor, etc., but is selected from the range of 10 μm to 1000 μm. Preferably, it is selected from 20 μm to 800 μm.

  FIG. 3 is a diagram showing an example of the temperature and vacuum degree history pattern of the vapor deposition chamber in the conventional vapor deposition method.

Usually, when a stimulable phosphor layer is formed on a substrate using a raw material mainly composed of a stimulable phosphor in an evaporation chamber, the vapor deposition chamber is evacuated to a predetermined vacuum degree P _While reducing the pressure to ₁ and heating the substrate to a predetermined temperature T ₁ , the raw material is evaporated and deposited on the substrate under certain conditions to form a photostimulable phosphor layer.

However, when vapor deposition is performed at a single degree of vacuum P ₁ and substrate temperature T ₁ , it is difficult to precisely control the formation of the photostimulable phosphor layer. Therefore, it is difficult to achieve both high quality and sharpness, and the occurrence of image defects is caused. Therefore, it is necessary to set a more precise vacuum degree and substrate temperature.

In the method for producing a radiation image conversion panel according to the present invention, in the formation of the photostimulable phosphor layer by the vapor deposition method, the deposition chamber is depressurized from the atmospheric pressure to a vacuum state, and the raw material is evaporated and deposited on the substrate. In the pre-deposition process, which is a pre-process of the process, the vapor deposition chamber is set to a degree of vacuum P ₂ higher than the degree of vacuum P ₁ set in the deposition process, and is higher than the base material temperature T ₁ set in the deposition process. The temperature is set to T ₂ and is maintained for a certain period of time, and in the post-deposition process, which is the post-deposition process in which all the raw materials are evaporated and deposited on the substrate, the degree of vacuum set in the deposition process The vacuum degree P ₃ is set lower than P ₁ , and the substrate temperature T ₃ is set lower than the substrate temperature T ₁ set in the deposition process, and is held for a certain time.

  In the present invention, it is possible to form a more precise photostimulable phosphor layer by setting the vacuum degree and temperature of the evaporation chamber to specific conditions in the pre-deposition process or the post-deposition process. Thus, a radiation image conversion panel free from image defects and excellent in both graininess and sharpness could be obtained.

  FIG. 4 is a diagram showing an example of temperature and vacuum degree history patterns in the pre-deposition process and the post-deposition process of the evaporation chamber according to the present invention.

As shown in FIG. 4, in the pre-deposition process, which is a pre-deposition process of forming the photostimulable phosphor layer on the substrate, the degree of vacuum P ₂ is higher than the degree of vacuum P ₁ in the deposition process. Hold for a certain time (holding time t ₂ ). Similarly, the substrate temperature T ₁ during the deposition process is maintained at a higher substrate temperature T ₂ for a certain time (holding time t ₂ ).

In the present invention, the degree of vacuum P ₁ in the deposition process is preferably 1.0 × 10 ^{−4 to} 5.0 × 10 ⁻¹ Pa, and the substrate temperature T ₁ is 50 to 300. It is preferable to set in the range of ° C.

At this time, as the degree of vacuum P ₂ in the pre-deposition process, the difference ΔP ₁ (P ₁ -P ₂ ) in the degree of vacuum with the degree P ₁ in the deposition process is 1.0 × 10 ⁻⁷ to 1 × 10 ^−4. It is preferably set to be in the range of Pa, more preferably 1.0 × 10 ^{−5 to} 5 × 10 ⁻¹ Pa. The substrate temperature T ₂ in the pre-deposition process is set so that the temperature difference ΔT ₁ (T ₂ −T ₁ ) with the substrate temperature T ₁ in the deposition process is in the range of 5 to 100 ° C. Is more preferable, and it is 10-50 degreeC more preferably.

As the holding time t ₂ of the vacuum degree P ₂ and the base temperature T ₂ in the pre-deposition process is preferably 0.01 to 0.50 times the process time t ₁ in the deposition process, and more preferably 0.01 to 0.25 times.

Similarly, in a post-deposition process, which is a process subsequent to the deposition process for forming the photostimulable phosphor layer on the substrate, the vacuum degree P ₁ in the deposition process is lower than the vacuum degree P ₃ for a certain time (retained). Hold at time t ₃ ). Similarly, the substrate temperature T ₁ during the deposition process is held at a lower substrate temperature T ₃ for a certain time (holding time t ₃ ).

At this time, as the degree of vacuum P ₃ in the post-deposition process, the difference ΔP ₂ (P ₃ -P ₁ ) in the degree of vacuum with the degree P ₁ in the deposition process is 1.0 × 10 ^{−3 to} 9 × 10 ^−. It is preferably set to be in the range of ¹ Pa, more preferably 1.0 × 10 ^{−2 to} 5 × 10 ⁻¹ Pa. Further, the base material temperature T ₃ in the pre-deposition process is set so that the temperature difference ΔT ₂ (T ₁ −T ₃ ) with the base material temperature T ₁ in the deposition process is in the range of 5 to 100 ° C. It is preferably 10 to 50 ° C.

Further, the holding time t ₃ of the degree of vacuum P ₃ and the substrate temperature T _{3 in} the post-deposition process is preferably 0.01 to 0.50 times the treatment time t ₁ in the deposition process, more preferably 0.01 to 0.25 times.

Further, in the method for producing a radiation image conversion panel of the present invention, from the viewpoint of further exerting the object effect of the present invention, in the above-described pre-deposition process, the vacuum degree P ₂ and the substrate temperature T ₂ are maintained for a certain time t _2. In addition, it is preferable to simultaneously heat the wall surfaces constituting the vapor deposition chamber, and the heating temperature is preferably set to a range of 50 to 300 ° C., more preferably the same temperature range (T2) as the substrate temperature T _2. It is preferable to set to ± 20 ° C.

In addition, the radiation image conversion panel manufacturing method of the present invention is characterized in that the degree of vacuum P ₁ is changed according to the elapsed time in the deposition process in which the raw material is evaporated and deposited on the substrate.

  FIG. 5 is a diagram showing an example of a history pattern for changing the degree of vacuum in the vapor deposition chamber during the deposition process.

In the deposition process, as the deposition progresses, the degree of vacuum is sequentially changed to P _1-1 , P _1-2 , P _1-3, and P _1-4 to form a photostimulable phosphor layer on the substrate. Form. FIG. 5 shows an example of a pattern in which the degree of vacuum is high immediately after the start of deposition and is sequentially shifted to a low degree of vacuum. Even if it exists, the pattern which changes a vacuum degree at random may be sufficient.

  In FIG. 5, the vacuum degree and substrate temperature pattern shown in FIG. 4 may be combined as the vacuum degree and substrate temperature pattern in the pre-deposition process and the post-deposition process.

In the radiation image conversion panel manufacturing method of the present invention, the evaporation chamber has a plurality of raw material evaporation means, and when the raw material evaporation means is sequentially evaporated in any combination and deposited on the substrate, the evaporation of each raw material is performed. It is preferable to change the degree of vacuum P ₁ every time to form a photostimulable phosphor layer on the substrate, and the degree of vacuum P ₁ to be changed for each elapsed time or evaporation of the raw material depends on the initial degree of vacuum. A pattern that is lowest and then increases the degree of vacuum is preferred.

  FIG. 6 is a diagram showing an example of a pattern having a plurality of raw material evaporation means and changing the degree of vacuum in the deposition process.

In the deposition process, the degree of vacuum is set to P _1-5 , P _1-6 , P _1-7 and P ₁₋ using a plurality of raw material evaporation means 36-1, 36-2, 36-3, 36-4, respectively. _{8. The} photostimulable phosphor layer is formed on the base material by sequentially changing the degree of vacuum from ₈ to ₈ . By forming the photostimulable phosphor layer according to the conditions defined above, a radiation image conversion panel free from image defects and excellent in both graininess and sharpness can be obtained.

  In FIG. 6, the vacuum degree and substrate temperature pattern shown in FIG. 4 may be combined as the vacuum degree and substrate temperature pattern in the pre-deposition process and the post-deposition process.

  Further, in the radiation image conversion panel manufacturing method of the present invention, the evaporation chamber has a plurality of raw material evaporation means, and when the raw material evaporation means are sequentially evaporated in any combination to deposit on the base material, the material is deposited on the base material. It is preferable to repeat the operation in which the degree of vacuum in the deposition process is changed from low vacuum to high vacuum, then returned to low vacuum, and set to high vacuum again.

  FIG. 7 is a diagram showing an example of another pattern having a plurality of raw material evaporation means and changing the degree of vacuum in the deposition process.

In the deposition process, the degree of vacuum is set to P _1-9 , P _1-10 , P _1-11 and P ₁₋ using a plurality of raw material evaporation means 36-1, 36-2, 36-3, 36-4, respectively. _{12 By} changing the pattern from low vacuum to high vacuum, then returning to low vacuum and then repeating high vacuum again, a radiation image conversion panel with no image defects and excellent graininess and sharpness can be obtained. Can be obtained.

  Further, in the present invention, when there are a plurality of raw material evaporation means, and when the raw material evaporation means sequentially evaporates the raw materials in an arbitrary combination and deposit them on the substrate, the raw material evaporation means for performing the next evaporation is preliminarily evaporated. As a result, it is possible to obtain a radiation image conversion panel free from image defects and excellent in both graininess and sharpness.

  In FIG. 7, the vacuum degree and substrate temperature pattern shown in FIG. 4 may be combined as the vacuum degree and substrate temperature pattern in the pre-deposition process and the post-deposition process.

  Next, the plurality of raw material evaporation means described above and the heating method thereof will be described.

  FIG. 8 is a schematic view showing an example of the configuration of the raw material evaporation means and the heating means in the vapor deposition chamber used in the vapor deposition method according to the present invention.

FIG. 8 shows an example in which four raw material evaporation means are provided. In FIG. 8, the vapor deposition chamber 31 is once evacuated to a certain value or less by a pre-exhaust means (not shown) via a main valve 32, and further the degree of vacuum is set via a leak valve 33 by a non-illustrated post-exhaust means. Maintained below the value. An inert gas such as N ₂ , Ar, Ne, and He is introduced into the vapor deposition chamber as an atmospheric gas through a gas introduction valve 34 as necessary. Further, the vapor deposition chamber 31 is provided with a vacuum gauge 38 for measuring the internal vacuum degree.

  The vapor deposition chamber 31 is provided with a base material arrangement means 35 at the top, and the base material 30 can be arranged. A plurality of the substrates 30 may be arranged, or may be arranged at any position of the substrate arrangement means 35. The substrate arrangement means 35 need not be fixed, and may be rotated or reciprocated. . In addition, a temperature sensor (not shown) for measuring the temperature of the base material 30 and a heater (not shown) for heating the base material 30 are embedded in the base material arranging means 35. Can be brought to a predetermined temperature. Moreover, the raw material evaporation means 36-1 to 36-4 which hold | maintained the raw material are arrange | positioned in the lower part.

  FIG. 9 is a view taken along the line BB ′ in FIG. A plurality of raw material evaporation means 36-1 to 36-4 are provided below the base material arranging means (not shown), and a predetermined amount of the stimulable phosphor as the raw material is charged into the raw material container. In FIG. 9, the raw material heating means in the raw material evaporation means is a so-called resistance heating method, and current is supplied to the raw material evaporation means 36-1 to 36-4 by the current supply units 37-1 to 37-4 to heat them. Is done.

  Next, the configuration of the radiation image conversion panel of the present invention will be described.

In the vapor deposition method according to the present invention, examples of the stimulable phosphor as an evaporation source include phosphors represented by BaSO ₄ : Ax described in JP-A-48-80487, A phosphor represented by MgSO ₄ : Ax described in Japanese Patent No. 48-80488, a phosphor represented by SrSO ₄ : Ax described in Japanese Patent Laid-Open No. 48-80489, and a phosphor represented by Japanese Patent Laid-Open No. 51-29889. Phosphors obtained by adding at least one of Mn, Dy, and Tb to Na ₂ SO ₄ , CaSO _4, BaSO _{4, and the} like, BeO, LiF, MgSO _4, and CaF described in JP-A-52-30487 ₂ , phosphors such as Li ₂ B ₄ O ₇ : Cu, Ag described in JP-A-53-39277, Li ₂ O. ( _{Be 2 O 2) x: Cu} , Ag Phosphors are described in U.S. Pat. No. 3,859,527 SrS: Ce, Sm, SrS : Eu, Sm, La 2 O 2 S: Eu, Sm and (Zn, Cd) S: Tables in Mnx Phosphors to be used. Further, a ZnS: Cu, Pb phosphor described in JP-A No. 55-12142, a barium aluminate phosphor whose general formula is BaO.xAl ₂ O ₃ : Eu, and a general formula of M (II ) O.xSiO ₂ : An alkaline earth metal silicate phosphor represented by A can be used.

Further, an alkaline earth fluorohalide phosphor represented by the general formula (Ba _1-xy Mg _x Ca _y ) F _x : Eu ²⁺ described in Japanese Patent Laid-Open No. 55-12143, A phosphor in which the general formula described in Japanese Patent No. 55-12144 is represented by LnOX: xA, and a general formula described in Japanese Patent Laid-Open No. 55-12145 is (Ba _1-x M (II) _x ) F _x : A phosphor represented by yA, a phosphor represented by the general formula described in JP-A-55-84389, BaFX: xCe, yA, a formula represented by JP-A-55-160078 Is a rare earth element activated divalent metal fluorohalide phosphor represented by M (II) FX.xA: yLn, fluorescence represented by the general formula ZnS: A, CdS: A, (Zn, Cd) S: A, X And any one of the following general formulas described in JP-A-59-38278 xM ₃ (PO ₄ ) ₂ · NX ₂ : yA
xM ₃ (PO ₄ ) ₂ : yA
A phosphor represented by the general formula nReX ₃ · mAX ′ ₂ : xEu described in JP-A-59-155487
nReX ₃ · mAX ′ ₂ : xEu, ySm
In phosphor represented by the following general formula M (I) X · aM that is described in _{JP-A-61-72087 (II) X '2 ·} bM (III) X "3: cA
And a bismuth-activated alkali halide phosphor represented by the general formula M (I) X: xBi described in JP-A No. 61-228400. In particular, the alkali halide phosphor is preferable because a columnar photostimulable phosphor layer can be easily formed by a method such as vapor deposition or sputtering.

  In the present invention, stimulable phosphor particles represented by the following general formula (1) are preferred.

General formula (1)
M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : eA
In the general formula (1), M ¹ is at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs, and M ² is Be, Mg, Ca, Sr, Ba, Zn, Cd. , Cu and Ni, and M ³ is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er. , Tm, Yb, Lu, Al, Ga and In, at least one trivalent metal selected from the group consisting of In, X, X ′ and X ″ are each selected from the group consisting of F, Cl, Br and I At least one halogen, and A is Eu, Tb, In, Cs, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu And at least one selected from the group consisting of Mg A metal, also, a, b, e each represent a number between 0 ≦ a <0.5,0 ≦ b <0.5,0 <e ≦ 0.2.

Further, in the general formula (1), M ¹ is at least one alkali metal selected from the group consisting of K, Rb and Cs, and X is at least one halogen selected from Br and I. M ² is at least one divalent metal selected from Be, Mg, Ca, Sr and Ba, M ³ is Y, Ce, Sm, Eu, Al, La, Gd, Lu, Ga and In At least one trivalent metal selected from the group consisting of: b is 0 ≦ b ≦ 10 ⁻² , A is at least one selected from the group consisting of Eu, Cs, Sm, Tl and Na A seed metal is preferred.

  The stimulable phosphor according to the present invention preferably has a columnar crystal, and the main component of the columnar crystal is preferably a stimulable phosphor represented by the following general formula (1).

General formula (1)
CsX: A
In the general formula (1), X represents Br or I, and A represents Eu, In, Tb, or Ce.

  In the present invention, the evaporation source is not necessarily limited to the stimulable phosphor, and may be a mixture of the stimulable phosphor material. Moreover, what activator mixed the activator with respect to a base substance (basic substance) may be vapor-deposited, and after depositing only a base material, you may dope an activator. For example, after depositing only RbBr which is a base material, for example, Tl which is an activator may be doped. Doping can be performed by thermal diffusion and ion implantation of a doping agent (activator) in the base layer of the formed phosphor.

  Further, the photostimulable phosphor layer may be filled with a substance having a high light absorption rate, a substance having a high light reflectance, or the like. As a result, the stimulable phosphor layer has a reinforcing effect, and the lateral diffusion of the stimulated excitation light incident on the stimulable phosphor layer can be almost completely prevented.

  A substance having high light reflectance means a material having a high reflectance with respect to stimulated excitation light (500 to 900 nm, particularly 600 to 800 nm), such as white pigment and green to red, such as aluminum, magnesium, silver, indium and other metals. Area colorants can be used.

White pigments can also reflect stimulated emission. As white pigments, 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 At least one of Ca, and X is at least one of Cl and Br.), CaCO ₃ , ZnO, Sb ₂ O ₃ , SiO ₂ , ZrO ₂ , lithopone (BaSO ₄ .ZnS) , Magnesium silicate, basic lead silicic acid sulfate, basic lead phosphate, aluminum silicate and the like. Since these white pigments have strong hiding power and a high refractive index, they can easily scatter stimulated luminescence by reflecting or refracting light, and can significantly improve the sensitivity of the resulting radiation image conversion panel.

  Moreover, as a substance having a high light absorption rate, for example, carbon, chromium oxide, nickel oxide, iron oxide and the like and a blue color material are used. Of these, carbon also absorbs stimulated luminescence.

The color material may be either an organic or inorganic color material. Examples of organic colorants include Zavon First Blue 3G (Hoechst), Estrol Brill Blue N-3RL (Sumitomo Chemical), D & C Blue No. 1 (made by National Aniline), Spirit Blue (made by Hodogaya Chemical), Oil Blue No. 1 603 (made by Orient), Kitten Blue A (made by Ciba Geigy), Eisen Katyron Blue GLH (made by Hodogaya Chemical), Lake Blue AFH (made by Kyowa Sangyo), Primocyanin 6GX (made by Inabata Sangyo), Brill Acid Green 6BH (Hodogaya) Chemical Blue), Cyan Blue BNRCS (Toyo Ink), Lionoyl Blue SL (Toyo Ink), etc. are used. The color index No. 24411, 23160, 74180, 74200, 22800, 23154, 23155, 24401, 14830, 15050, 15760, 15707, 17941, 74220, 13425, 13361, 13420, 11836, 74140, 74380, 74350, 74460, etc. Materials are also mentioned. Examples of inorganic color materials include ultramarine blue, cobalt blue, cerulean blue, chromium oxide, and TiO ₂ —ZnO—Co—NiO pigments.

  In the radiation image conversion panel of the present invention, a protective layer may be provided on the photostimulable phosphor layer. The protective layer may be formed by directly applying a coating solution for the protective layer on the photostimulable phosphor layer, or a protective layer separately formed in advance may be adhered on the photostimulable phosphor layer. Or you may take the procedure of forming a photostimulable phosphor layer on the protective layer formed separately. Examples of the protective layer material include cellulose acetate, nitrocellulose, polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene, polyvinylidene chloride, nylon, polytetrafluoroethylene, and polytrifluoride. Common protective layer materials such as ethylene chloride, ethylene tetrafluoride-hexafluoropropylene copolymer, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer are used. Further, this protective layer may be formed by laminating inorganic substances such as SiC, SiO2, SiN, Al2O3, etc. by vapor deposition, sputtering, or the like. In general, the thickness of these protective layers is preferably about 0.1 μm to 2000 μm.

  In addition, those having good translucency and capable of being formed into a sheet can be used, and examples thereof include plate glass such as quartz, borosilicate glass and chemically tempered glass, and organic polymers such as PET, OPP and polyvinyl chloride. It is done.

  As the base material used in the radiation image conversion panel of the present invention, various glasses, polymer materials, metals and the like are used. For example, plate glass such as quartz, borosilicate glass, chemically tempered glass, and 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, an aluminum sheet, an iron sheet, a copper sheet, or a metal sheet having a coating layer of the metal oxide is preferred. . The surface of these base materials 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 base material and a photostimulable phosphor layer, you may provide an adhesive layer in advance on the surface of a base material as needed.

  Although the thickness of these base materials varies depending on the material of the base material used, etc., it is generally 80 μm to 2000 μm, and more preferably 80 μm to 1000 μm from the viewpoint of handling.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1
<Production of radiation image conversion panel>
[Preparation of Sample 1]
A substrate is a stimulable phosphor layer having a stimulable phosphor (CsBr: Eu) on a 1 mm thick crystallized glass (manufactured by Nippon Electric Glass Co., Ltd.) using the vapor deposition apparatus shown in FIGS. Was formed with the degree of vacuum and substrate temperature pattern described in FIG.

  In forming the photostimulable phosphor layer, the substrate was placed in a vapor deposition chamber, and then the phosphor raw material was placed in a raw material container as a vapor deposition source. Thereafter, the evaporation chamber is once evacuated, and then Ar gas is introduced to adjust the degree of vacuum to 0.133 Pa, and then the plurality of raw material evaporation means 36-1 to 36-36 are maintained while maintaining the temperature of the substrate at about 200 ° C. 4 was heated in order and vapor deposition was performed. At this time, the distance between the substrate and the evaporation source was adjusted to 60 cm, and the thickness of the stimulable phosphor layer was adjusted to 300 μm. When the photostimulable phosphor layer has reached a thickness of 300 μm, the evaporation is stopped, the heating of the substrate and the introduction of Ar gas are stopped, the vapor deposition chamber is returned to atmospheric pressure, and the substrate on which the raw material is deposited is taken out. It was. Thereafter, in a dry air atmosphere, the periphery of the protective layer made of a base material and borosilicate glass was sealed with an adhesive to prepare Sample 1, which is a radiation image conversion panel having a structure in which the phosphor layer is sealed.

[Preparation of Sample 2]
A substrate is a stimulable phosphor layer having a stimulable phosphor (CsBr: Eu) on a 1 mm thick crystallized glass (manufactured by Nippon Electric Glass Co., Ltd.) using the vapor deposition apparatus shown in FIGS. Was formed with the vacuum degree and substrate temperature pattern (applying only the pattern of the pre-deposition process) described in FIG.

  After the base material is installed in the vapor deposition chamber, the phosphor raw material is placed in a raw material container as a vapor deposition source, the vapor deposition chamber is once evacuated, Ar gas is then introduced, and the degree of vacuum is adjusted to 0.0133 Pa. The temperature of the material was kept at 250 ° C. for 0.5 hours. Next, the degree of vacuum was adjusted to 0.133 Pa, and the plurality of raw material evaporation means 36-1 to 36-4 were heated in order while the base material temperature was maintained at 200 ° C. to perform evaporation. At this time, the distance between the substrate and the evaporation source was adjusted to 60 cm, and the thickness of the stimulable phosphor layer was adjusted to 300 μm. When the photostimulable phosphor layer has reached a thickness of 300 μm, the evaporation is stopped, the heating of the substrate and the introduction of Ar gas are stopped, the vapor deposition chamber is returned to atmospheric pressure, and the substrate on which the raw material is deposited is taken out. It was. Thereafter, in a dry air atmosphere, the periphery of the protective layer made of a base material and borosilicate glass was sealed with an adhesive to prepare Sample 2, which is a radiation image conversion panel having a structure in which the phosphor layer is sealed.

[Preparation of Sample 3]
A substrate is a stimulable phosphor layer having a stimulable phosphor (CsBr: Eu) on a 1 mm thick crystallized glass (manufactured by Nippon Electric Glass Co., Ltd.) using the vapor deposition apparatus shown in FIGS. Was formed with the vacuum degree and substrate temperature pattern shown in FIG. 4 (applying only the post-deposition process pattern).

  After evacuating the evaporation chamber and then introducing Ar gas to adjust the degree of vacuum to 0.133 Pa, the plurality of raw material evaporation means 36-1 to 36-4 are maintained while maintaining the temperature of the substrate at about 200 ° C. Evaporation was performed by heating in order. At this time, the distance between the substrate and the evaporation source was adjusted to 60 cm, and the thickness of the stimulable phosphor layer was adjusted to 300 μm. Evaporation was terminated when the thickness of the photostimulable phosphor layer reached 300 μm, and the vacuum in the vapor deposition chamber was maintained at 0.5 Pa and the substrate temperature was maintained at 150 ° C. for 0.5 hours. Then, after heating the base material and Ar stopped introducing the gas, the vapor deposition chamber was returned to atmospheric pressure, and the base material on which the raw material was deposited was taken out. Thereafter, in a dry air atmosphere, the periphery of the protective layer made of a base material and borosilicate glass was sealed with an adhesive to prepare Sample 3, which is a radiation image conversion panel having a structure in which the phosphor layer is sealed.

<< Evaluation of radiation image conversion panel >>
Each of the following samples 1 to 3 was evaluated.

[Evaluation of sharpness]
As for the sharpness of each sample, a modulation transfer function (MTF) was measured and used as a measure of sharpness.

  In the MTF, after attaching a CTF chart to each sample which is a radiation image conversion panel, each sample is irradiated with 80 kVp X-rays at 10 mR (distance to the subject: 1.5 m), and then a semiconductor laser (680 nm in diameter of 100 μmφ). : Obtained by scanning and reading a CTF chart image using a power of 40 mW on the panel). The sharpness is represented by a relative value when the sharpness of the sample 1 is 1.00.

(Evaluation of graininess)
The granularity of each sample was evaluated by forming a radiographic image under the following X-ray irradiation conditions, and then reading the radiographic image using a semiconductor laser beam having a wavelength of 680 nm as excitation light. After reading the radiation image, the X-ray solid exposure image output to the film was visually observed, and the graininess was evaluated according to the following evaluation criteria.

X-ray irradiation conditions: 80 kVp, 200 mA, 0.1 sec
Film output condition: γ (gradation) = 3.0 output <Evaluation criteria>
5: Almost no graininess is observed, and the graininess is very good. 4: Although some graininess is observed, the quality is good. 3: Some graininess is observed. 2: There is a feeling of graininess. The quality is 1: Graininess is clearly conspicuous and cannot be used practically Table 1 shows the results obtained.

  As apparent from the results in Table 1, before the deposition process, the deposition chamber is set to a vacuum level higher than the vacuum level set in the deposition process, and the substrate temperature higher than the substrate temperature set in the deposition process is set. Sample 2 of the present invention prepared by holding for a certain period of time, or after the deposition process, set to a vacuum level lower than the vacuum level set in the deposition process, and higher than the substrate temperature set in the deposition process It can be seen that Sample 3 produced by setting the substrate temperature at a low temperature and holding it for a certain period of time is superior in sharpness and graininess to the comparative example formed under a single condition.

Example 2
<Production of radiation image conversion panel>
[Preparation of Samples 4 to 6]
In the preparation of the sample 1 described in Example 1 (pattern in FIG. 3), when the raw material evaporation means 36-1 to 36-4 are sequentially heated to deposit the raw material on the base material, the respective vacuum degrees are shown in Table 2. Samples 4 to 6 were prepared in the same manner except that the photostimulable phosphor layer was formed with the vacuum pattern shown in FIGS.

[Preparation of Sample 7]
Sample 7 was prepared in the same manner as in preparation of Sample 1 described in Example 1 (pattern in FIG. 3) except that the degree of vacuum when depositing the raw material on the substrate was changed to 0.05 Pa.

<< Evaluation of radiation image conversion panel >>
For the samples 4 to 7 prepared above and the sample 1 prepared in Example 1, evaluation of sharpness and granularity was performed in the same manner as in Example 1, and image defects were evaluated according to the following method. The results obtained are shown in Table 2.

(Evaluation of image defects)
Inspection equipment for evaluation: Regius 330 (manufactured by Konica Minolta MG Co., Ltd.)
Evaluation conditions: Under the conditions of 80 kVp and 70 mA, X-ray imaging was performed with the distance between the X-ray tube and the radiation image conversion panel being 2 m.

Evaluation method: Under the above imaging conditions, image information after X-ray imaging was read to obtain a β image signal. This β image signal was divided every 2000 × 2000 pixels to obtain a signal value for each pixel. Among the obtained image signals, pixels having a difference of 50 steps or more between adjacent signal values were detected, and this number of pixels per 10 cm ² was defined as the number of defects. As the number of pixels having a signal difference increases, the number of defects increases and affects image diagnosis.

  As is clear from the results in Table 2, when a plurality of raw material evaporation means are provided and the raw material evaporation means are sequentially evaporated in an arbitrary combination, the degree of vacuum is changed for each evaporation of the raw materials. It can be seen that the sample of the present invention is excellent in sharpness and graininess and has few image defects as compared with the comparative example produced under a certain condition.

Example 3
<Production of radiation image conversion panel>
[Preparation of Sample 8]
In the preparation of the sample 1 described in Example 1 (pattern in FIG. 3), when the raw material evaporation means 36-1 to 36-4 are sequentially heated to deposit the raw material on the substrate, the raw material evaporation means 36- The raw material evaporation means 36-2 is preheated during the deposition of one raw material, the raw material evaporation means 36-3 is preheated during the raw material deposition of the raw material evaporation means 36-2, and the raw material deposition of the raw material evaporation means 36-3 is performed. Sample 8 was prepared in the same manner except that the raw material evaporation means 36-4 was preheated.

<< Evaluation of radiation image conversion panel >>
For the sample 8 prepared above and the sample 1 prepared in Example 1, evaluation of image defects and comparison of total raw material deposition time were performed in the same manner as in Example 2, and the results obtained are shown in Table 3. Show. The total raw material deposition time was expressed as a relative time with 1.00 being the time required for forming the photostimulable phosphor layer of Sample 1.

  As is clear from the results in Table 2, when the raw material evaporation means has a plurality of raw material evaporation means and the raw material evaporation means are sequentially evaporated in any combination and deposited on the substrate, the raw material evaporation means to be evaporated next is previously set. The sample of the present invention produced by preheating and holding within the range where evaporation of the raw material does not occur has a smaller number of image defects and shorter time required for forming the photostimulable phosphor layer than the comparative example. I understand.

It is sectional drawing which shows an example of the structure of the photostimulable phosphor layer formed by the vapor deposition method which comprises the radiographic image conversion panel of this invention. It is the schematic which shows an example of the radiographic image conversion method using the radiographic image conversion panel of this invention. It is a figure which shows an example of the temperature of a vapor deposition chamber, and a vacuum degree log | history pattern in the conventional vapor deposition method. It is a figure which shows an example of the temperature and vacuum degree log | history pattern in the process before deposition of the evaporation chamber of this invention, and the process after deposition. It is a figure which shows an example of the log | history pattern which changes the vacuum degree of a vapor deposition chamber in the deposition process of this invention. It is a figure which shows an example of the pattern which has a some raw material evaporation means and changes the vacuum degree of a deposition process. It is a figure which shows an example of the other pattern which has a some raw material evaporation means and changes the vacuum degree of a deposition process. It is the schematic which shows an example of a structure of the raw material evaporation means and heating means of a vapor deposition chamber used with the vapor phase deposition method which concerns on this invention. It is a BB 'arrow line view in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 30 Base material 12 Stimulable phosphor layer 13 Protective layer 21 Radiation generation device 22 Subject 23 Radiation image conversion panel 24 Stimulation excitation light source 25 Photoelectric conversion device 26 Reproduction device 27 Display device 28 Filter 31 Deposition chamber 32 Main valve 33 leak valve 34 gas introduction valve 35 substrate positioning means 36-1,36-2,36-3,36-4 material evaporation means 37-1,37-2,37-3,37-4 current supply unit T ₁ deposited Substrate temperature in the process P ₁ Degree of vacuum in the deposition process T ₂ Substrate temperature in the pre-deposition process P ₂ Degree of vacuum in the pre-deposition process T ₃ Substrate temperature in the post-deposition process P ₃ Degree of vacuum in the post-deposition process t ₁ Deposition time t ₂ retention time of the pre-deposition process t ₃ retention time of the post-deposition process

Claims (10)

In a method for producing a radiation image conversion panel in which at least one photostimulable phosphor layer is formed on a substrate using a film forming apparatus for depositing a raw material by a vapor deposition method,
The film forming apparatus includes an evacuation unit that depressurizes the vapor deposition chamber with an evacuation unit and makes a vacuum state, and a vacuum gauge that measures the degree of vacuum in the vapor deposition chamber,
The vapor deposition chamber has a base material placement means and a raw material evaporation means for depositing a raw material mainly composed of a stimulable phosphor on the surface of the placed base material,
The vapor deposition chamber has a substrate heating means, a substrate temperature measurement or a substrate temperature estimation means,
Prior to the deposition process in which the deposition chamber is depressurized from atmospheric pressure to a vacuum state, and the raw material is evaporated and deposited on the substrate, a vacuum higher than the degree of vacuum P ₁ set in the deposition process. degrees is set to P _2, and the radiation image conversion panel manufacturing method characterized by and set to a higher substrate temperature T ₂ than the base material temperatures T ₁ to be set in the deposition process holding a certain time. The radiation image conversion panel manufacturing method according to claim 1, wherein the vacuum chamber P ₂ and the substrate temperature T ₂ are simultaneously heated for a predetermined time before the deposition process, and the wall surface of the vapor deposition chamber is simultaneously heated. Method. In a method for producing a radiation image conversion panel in which at least one photostimulable phosphor layer is formed on a substrate using a film forming apparatus for depositing a raw material by a vapor deposition method,
The film forming apparatus includes an evacuation unit that depressurizes the vapor deposition chamber with an evacuation unit and makes a vacuum state, and a vacuum gauge that measures the degree of vacuum in the vapor deposition chamber,
The vapor deposition chamber has a base material placement means and a raw material evaporation means for depositing a raw material mainly composed of a stimulable phosphor on the surface of the placed base material,
The vapor deposition chamber has a substrate heating means and a substrate temperature measurement or substrate temperature estimation means, and is set in the deposition process after the deposition process in which all the raw materials are evaporated and deposited on the substrate. The radiation is characterized in that it is set to a vacuum level P ₃ lower than the vacuum level P ₁ to be set, and is set to a base material temperature T ₃ lower than the base material temperature T ₁ set in the deposition process and held for a certain period of time. Image conversion panel manufacturing method. In a method for producing a radiation image conversion panel in which at least one photostimulable phosphor layer is formed on a substrate using a film forming apparatus for depositing a raw material by a vapor deposition method,
The film forming apparatus includes an evacuation unit that depressurizes the vapor deposition chamber with an evacuation unit and makes a vacuum state, and a vacuum gauge that measures the degree of vacuum in the vapor deposition chamber,
The vapor deposition chamber has a base material placement means and a raw material evaporation means used in a deposition process for depositing a raw material mainly composed of a stimulable phosphor on the surface of the placed base material. A method of manufacturing a radiation image conversion panel, wherein the degree of vacuum P ₁ is changed according to elapsed time in a deposition process of depositing on a material. A plurality of the raw material evaporation means are provided, and when the raw material evaporation means are sequentially evaporated in an arbitrary combination and deposited on the substrate, the degree of vacuum P ₁ is changed for each evaporation of the raw materials. The method for producing a radiation image conversion panel according to claim 4. 6. The radiation image conversion panel manufacturing method according to claim 4, wherein the vacuum degree P ₁ to be changed at each of the elapsed time or the evaporation of the raw material is lowest in the initial vacuum degree and then increased in the vacuum degree. Method. The radiographic image according to claim 6, wherein the vacuum degree in the deposition process of depositing on the base material is changed from low vacuum to high vacuum, then returned to low vacuum, and again set to high vacuum. Conversion panel manufacturing method. In a method for producing a radiation image conversion panel in which at least one photostimulable phosphor layer is formed on a substrate using a film forming apparatus for depositing a raw material by a vapor deposition method,
The film forming apparatus includes an evacuation unit that depressurizes the vapor deposition chamber with an evacuation unit and makes a vacuum state, and a vacuum gauge that measures the degree of vacuum in the vapor deposition chamber,
The vapor deposition chamber has a base material placement means and a raw material evaporation means for depositing a raw material mainly composed of a stimulable phosphor on the surface of the placed base material,
A plurality of the raw material evaporation means, and when the raw material evaporation means are sequentially evaporated in any combination and deposited on the base material, the raw material evaporation means to be evaporated next is a range in which the raw material does not evaporate in advance. A method of manufacturing a radiation image conversion panel, wherein the preheating is carried out and held. It is a radiographic image conversion panel manufactured by the radiographic image conversion panel manufacturing method of any one of Claims 1-8, Comprising: It is contained in the at least 1 layer of photostimulable phosphor layer formed on the base material Radiation image conversion panel, wherein the stimulable phosphor has columnar crystals. The radiation image conversion panel according to claim 9, wherein the main component of the columnar crystal is a stimulable phosphor represented by the following general formula (1).
General formula (1)
CsX: A
[Wherein, X represents Br or I, and A represents Eu, In, Tb or Cs. ]

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