JP2008139156A - Planar radiation image detector manufacturing method - Google Patents

Abstract

The present invention provides a manufacturing method that enables formation of a phosphor layer free from adhesion of foreign matter or the like on a deposition start surface in the manufacture of a planar radiation image detector that forms a phosphor layer by vacuum deposition.
As a shutter that shields film-forming material vapor from an evaporation source, a shutter that is a predetermined size larger than the size of the film-forming material diffused and the movement error of the shutter is used, and the temperature of the film-forming material is the melting point In accordance with the time T related to the evaporation of all the film forming materials from the time when the temperature reaches + 10 ° C., the vapor deposition starts at 0.1 T or later from the time when the film forming material reaches the temperature, and the vapor deposition occurs before 0.9 T. The above-mentioned problem is solved by terminating the above.
[Selection] Figure 2

Description

  The present invention relates to a planar radiation image detector having a phosphor layer that emits light upon incidence of radiation and a two-dimensionally arranged photoelectric conversion element that detects light emission of the phosphor layer. The present invention relates to a method of manufacturing a planar radiation image detector that is formed by vacuum deposition.

Conventionally, radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.) transmitted through an object is used as an electrical signal for taking medical diagnostic images and industrial nondestructive inspections. Radiographic image detectors that capture radiographic images by taking them out are used.
Examples of the radiation image detector include a flat radiation image detector (hereinafter referred to as FDP) that extracts radiation as an electrical image signal, and an X-ray image tube that extracts a radiation image as a visible image.

  Further, for example, the FPD collects electron-hole pairs (e-h pairs) generated by a photoconductive film such as amorphous selenium by radiation incident in an electric field and reads them as electric signals. It has a direct method for converting it into a signal and a phosphor layer (scintillator layer) formed of a phosphor that emits light (fluorescence) when incident on radiation, and this phosphor layer converts radiation into visible light. Are read by a photoelectric conversion element, that is, an indirect method of converting radiation into an electric signal as visible light.

The indirect FPD as described above is formed by a photoelectric conversion element portion in which photoelectric conversion elements are two-dimensionally arranged, such as a photodiode using amorphous silicon or the like and a photoelectric conversion element made of TFT (Thin Film Transistor). In general, the phosphor layer is directly formed on the surface of the light detection panel (the surface on the light receiving side of the photoelectric conversion element).
In addition, as a method for forming the phosphor layer, a coating method in which phosphor powder is dispersed in a solvent containing a binder is prepared, and the coating is applied to the surface of the light detection panel and dried. As disclosed in Patent Document 1, there is a method of forming a phosphor layer by vacuum deposition using a light detection panel as a film formation substrate.
The method of forming the phosphor layer by vacuum deposition is low in impurities because the phosphor layer is formed in a vacuum, and there is little variation in performance because it contains almost no components other than phosphors such as a binder. It has an excellent characteristic that the efficiency is very good.

JP-A-57-7051

In CR (Computed Radiography) using a radiation image conversion panel (so-called Imaging Plate (IP)) having a stimulable phosphor layer, the radiation transmitted through the subject is recorded (photographed) on the radiation image conversion panel, and then the stimuli Excitation light is incident on the phosphor layer to cause stimulated emission, and the stimulated emission is photoelectrically read by a CCD sensor or the like to obtain a radiation image.
For this reason, the CR generally reads the stimulated emission on the radiation incident surface. Therefore, in the radiation image conversion panel, the property of the radiation incident surface, that is, the vapor deposition end surface is important.

On the other hand, in radiographic imaging using an indirect type FPD, radiation that has passed through the subject is incident on the phosphor layer from the surface of the phosphor layer on the opposite side of the light detection panel, and fluorescence due to the incidence of this radiation. The light emitted from the body layer is photoelectrically read by the light detection panel. That is, the FPD has a configuration in which the emitted light = radiation image is read from the surface on the light detection panel side, that is, the surface on the substrate side of vacuum deposition.
Therefore, in FPD, the property of the vapor deposition start surface of the phosphor layer, that is, the surface of the light detection panel (film formation substrate) is very important. For example, if there are foreign matter or abnormally grown crystals on the surface of the light detection panel, As a result, scattering of the emitted light of the phosphor layer occurs.

However, when the phosphor layer is formed by ordinary vacuum deposition as disclosed in Patent Document 1, unnecessary phosphors adhere to the surface of the light detection panel, which is a substrate, before the phosphor layer is formed. In some cases, foreign matter or abnormally grown crystals may be attached due to bumping or the like due to partial heating in the inside.
As a result, image quality degradation caused by foreign matter or the like on the surface of the detection panel occurs, so that a high-quality FPD cannot be stably manufactured.

  An object of the present invention is to solve the above-described problems of the prior art, and light emission (fluorescence) is caused by the incidence of radiation on the surface (light incident surface side) of a light detection panel on which photoelectric conversion elements are two-dimensionally formed. ) In the manufacture of a flat radiation image detector (FPD) in which a fluorescent multilayer made of fluorescent material is formed by vacuum vapor deposition, foreign matter is deposited on the surface of the light detection panel (support) serving as a deposition substrate of the phosphor layer, that is, the film formation substrate Providing a manufacturing method that can stably produce a planar radiation detector that can prevent high-quality radiation images and prevent abnormal crystals from adhering and suppress deterioration in image quality due to light scattering caused by these There is to do.

  In order to solve the above-described problems, the present invention provides a planar radiation image detection in which a phosphor layer that emits light upon incidence of radiation is formed on a surface of a support having photoelectric conversion elements arranged two-dimensionally by vacuum deposition. The phosphor layer is formed by vacuum vapor deposition with a vacuum degree of 0.1 to 10 Pa, and the film forming material of the phosphor layer is heated, so that the temperature of the film forming material is reduced. The temperature of the film forming material becomes the melting point + 10 ° C. of the film forming material, where T is the time from when the material reaches the melting point + 10 ° C. until the film forming material accommodated in the evaporation source evaporates. After 0.1 T has elapsed from the point in time, the shutter for shielding the vapor discharged from the evaporation source is opened to start the deposition of the phosphor layer on the support, and the film forming material When the temperature of the film reaches the melting point of the film forming material + 10 ° C. Before 0.9T elapses, the shutter is closed to finish the deposition of the phosphor layer on the support. Further, the phosphor layer forming surface of the support is the upper surface, and the evaporation source is formed. A surface obtained by cutting a solid body having a material vapor discharge port as a lower surface and having a side surface connecting the periphery of the upper surface and the periphery of the lower surface in parallel with the phosphor layer forming surface at the position where the vapor is shielded by the shutter And the following formula “W ≧ 1.4 × (length of prospective surface + Δx)” is satisfied as the shutter, where Δx is a mechanical position error when opening and closing the shutter. A method for manufacturing a planar radiation image detector is provided, wherein a shutter having a length W in a direction parallel to the phosphor layer forming surface is used.

According to the present invention having the above-described configuration, in the production of a planar radiation image detector in which a phosphor layer is formed by vacuum deposition on a light detection panel in which photoelectric conversion elements using photodiodes or the like are two-dimensionally formed, vapor deposition is performed. Before starting, it is possible to prevent unnecessary film-forming material evaporated by heating or bumped film-forming material from adhering to the light detection panel (support) as the film-forming substrate, and the film-forming material is extremely evaporated. After stabilization, the shutter is opened and phosphor layer formation (film formation) begins, and the amount of film formation material in the evaporation source (crucible) decreases, resulting in abnormal evaporation, bumping, and alteration of the film formation material. Before the above occurs, the shutter is closed to complete the formation of the phosphor layer.
Therefore, according to the present invention, adhesion of foreign matter on the deposition start surface, that is, the surface of the light detection panel, or abnormal growth caused by bumping of the film formation material or unnecessary film formation material adhering to the light detection panel, etc. Crystal formation can be prevented, and the vapor deposition end surface (and the vicinity thereof) can also suppress deterioration due to alteration and the like and form a phosphor layer with good properties.
Therefore, according to the present invention, image quality degradation caused by scattering of emitted light of the phosphor layer due to foreign matter on the surface of the light detection panel, abnormal light emission due to altered phosphor on the radiation incident surface, and the like is greatly suppressed. A high-quality planar radiation image detection panel capable of obtaining a high-quality radiation image can be stably manufactured.

Hereinafter, the manufacturing method of the planar radiation image detector of this invention is demonstrated in detail.
In FIG. 1, the conceptual diagram of an example of the vacuum evaporation system which enforces the manufacturing method of the planar radiation image detector of this invention is shown.

  The vacuum vapor deposition apparatus 10 shown in FIG. 1 uses a photodetection panel (support) S in which photoelectric conversion elements are two-dimensionally arranged as a film-forming substrate, and has 0 on the surface (the light receiving surface side by the photoelectric conversion elements). A phosphor layer is formed by vacuum deposition in a medium vacuum of 1 to 10 Pa.

  As shown in FIG. 1, a vacuum vapor deposition apparatus 10 (hereinafter referred to as a vapor deposition apparatus 10) basically includes a vacuum chamber 12, a substrate rotating means 14, a crucible 18 serving as an evaporation source, a shutter 20, and a power source. 22, a control unit 24, and a shutter moving unit 26.

In the present invention, the light detection panel S serving as a film forming substrate is not particularly limited, and a phosphor layer such as a photoelectric conversion element composed of a photodiode (amorphous silicon or the like) and a TFT (Thin Film Transistor) due to the incidence of radiation. So-called indirect type planar radiation image detector (flat panel detection) such as a photodetection panel S in which photoelectric conversion elements that detect and detect light emission (fluorescence) emitted from the light are two-dimensionally arranged on a glass substrate All known light detection panels S used for flat panel detectors (hereinafter referred to as FDP) can be used.
As a specific example, photodetection in which independent photoconductive layers are two-dimensionally arranged for each pixel as disclosed in JP-A-60-240285 and JP-A-8-116044. Panel S is illustrated.

  The substrate of the light detection panel S (the substrate on which the photoelectric conversion element is formed) is not particularly limited, and is used in radiation image detectors such as glass, ceramics, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), and polyimide. Various sheet-like substrates are all available.

The light detection panel S may have a protective film that protects the photoelectric conversion element. Examples of the protective film include protective films made of glass, ceramics, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyimide, and the like. When the light detection panel S has a protective film for the photoelectric conversion element, the phosphor layer is usually formed on the protective film (the protective film serves as a vapor deposition surface).
In the present invention, the light detection panel S is not limited to one having a protective film, and a phosphor layer may be directly formed on the surface of the photoelectric conversion element, or a functional film other than the protective film. A phosphor layer may be formed on the functional film.

  In the present invention, the phosphor forming the phosphor layer (scintillator layer) is not particularly limited, and various phosphors that emit light (fluorescence) upon incidence of radiation can be used. A phosphor that emits light in a wavelength range of 800 nm is preferably used.

As a specific example, the basic composition formula (I):
M ^I X · aM ^II X ′ ₂ · bM ^III X ″ ₃ : zA
An alkali metal halide phosphor represented by the formula is preferably exemplified.
(In the above formula, M ^I represents at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs, and M ^II represents Be, Mg, Ca, Sr, Ba, Ni, Cu, Zn. And at least one alkaline earth metal or divalent metal selected from the group consisting of Cd, and M ^III is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, It represents at least one rare earth element or trivalent metal selected from the group consisting of Ho, Er, Tm, Yb, Lu, Al, Ga and In. X, X ′ and X ″ are F, Cl, Represents at least one halogen selected from the group consisting of Br and I, and A represents Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Na, Mg, Cu, Ag Represents at least one rare earth element or metal selected from the group consisting of Tl, Bi, and a, b and z are 0 ≦ a <0.5, 0 ≦ b <0.5 and 0 <z, respectively. <Represents a numerical value within the range of 1.0.)
In the basic composition formula (I), M ^I preferably includes at least Cs, X preferably includes at least I, and A is particularly preferably Tl or Na. . z is preferably a numerical value within the range of 1 × 10 ⁻⁴ ≦ z ≦ 0.1.

As another example, basic composition formula (II):
M ^II FX: zLn
The rare earth activated alkaline earth metal fluorohalide phosphors shown in FIG.
(In the above formula, M ^II represents at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca, and Ln represents Ce, Pr, Sm, Eu, Tb, Dy, Ho, Nd, Er, Represents at least one rare earth element selected from the group consisting of Tm and Yb, X represents at least one halogen selected from the group consisting of Cl, Br and I. z represents 0 <z ≦ 0. Represents a numeric value within the range of.
As M ^II in the above formula, Ba preferably accounts for more than half. Ln is particularly preferably Eu or Ce.

Among these, alkali metal halide phosphors represented by the general formula “CsI: Tl” of the basic composition formula (I) are preferably used.
In addition, LnTaO ₄ : (Nb, Gd), Ln ₂ SiO ₅ : Ce, LnOX: Tm (Ln is a rare earth element), Gd ₂ O ₂ S: Tb, Gd ₂ O ₂ S: A phosphor represented by Pr, Ce, ZnWO ₄ , LuAlO ₃ : Ce, Gd ₃ Ga ₅ O ₁₂ : Cr, Ce, HfO ₂ or the like is also preferably used.

In the illustrated vapor deposition apparatus 10, the vacuum chamber 12 is a known vacuum chamber (bell jar, vacuum chamber) formed of iron, stainless steel, aluminum, or the like and used in a vacuum vapor deposition apparatus.
Moreover, the vapor deposition apparatus 10 implements the manufacturing method of this invention, and forms a fluorescent substance layer in the above-mentioned light detection panel S by the vacuum evaporation of the medium vacuum of 0.1-10Pa. In order to introduce the inert gas into the vacuum chamber 12 (inside the film forming system) for performing vacuum deposition under the medium vacuum, or air for opening the atmosphere, etc. Gas introduction means 30 is provided. The gas introduction means 30 is not particularly limited, and is a known one used in a vacuum vapor deposition apparatus or the like having a connection means with a gas supply source such as a gas cylinder, a gas introduction amount (gas flow rate) adjustment means, and the like. It is possible to use.

  Phosphors that emit light upon incidence of radiation, in particular, the alkali metal halide phosphors and rare earth activated alkaline earth metal fluorohalide phosphors, particularly phosphors represented by “CsI: Tl”. When the phosphor layer is formed by vacuum deposition, it has a columnar crystal structure, but such a phosphor layer formed at a medium vacuum of 0.1 to 10 Pa has a good columnar crystal structure, sharpness and sensitivity. It is possible to manufacture an FPD excellent in the above.

A vacuum pump is connected to the vacuum chamber 10 for exhausting the inside of the vacuum chamber 12 to a predetermined degree of vacuum.
The vacuum pump is not particularly limited, and various types of vacuum pumps that can be used as long as the required ultimate vacuum can be achieved can be used. As an example, an oil diffusion pump, a cryopump, a turbomolecular pump or the like may be used, and a cryocoil or the like may be used in combination as an auxiliary.
In the present invention, the ultimate vacuum in the vacuum chamber 10 is not particularly limited, but the ultimate vacuum in the vacuum chamber 12 is preferably 8.0 × 10 ⁻⁴ Pa or less.

The substrate rotating means 14 holds and rotates the above-described light detection panel S above the vacuum chamber 12, and includes a rotation drive source 32, a rotation shaft 34, and a substrate holder 36. Is done.
The rotation drive source 32 is a known rotation drive source configured by combining a motor, a gear, a bearing, and the like, and rotates the rotation shaft 34. In the illustrated vapor deposition apparatus 10, the rotating shaft 34 is arranged vertically above the crucible 18 (installation position of the crucible 18). That is, the rotation center of the light detection panel S is vertically above the crucible 18 (its center).

A substrate holder 36 is fixed to the lower end of the rotation shaft 34 (the end opposite to the rotation drive source 32). The substrate holder 36 holds the light detection panel S, which is a film formation substrate on which a phosphor layer is formed by vacuum deposition, and includes a disc-shaped main body 36a fixed to the rotating shaft 34, and a lower surface of the main body 36a. And a disk-shaped sheath heater 36b having the same diameter.
The main body 36a is fixed to the rotating shaft 34 at the center. The light detection panel S is fixed to the lower surface of the sheath heater 36b. Therefore, the photodetection panel S is rotated immediately above the crucible 18 that is the evaporation source when the rotary drive source 32 rotates the rotary shaft 34.

The method for fixing the light detection panel S to the substrate holder 36 (sheath heater 36b) is not particularly limited, and is a method using a fixing jig, and a fixing frame for holding the periphery of the light detection panel S from below. Various known plate-like holding / fixing methods such as a method using a magnetic field, a method using magnetic force or static electricity, and a method using fitting can be used.
The sheath heater 36b is also a known plate-shaped heating heater, and heats the light detection panel S on which the phosphor layer is formed (= the phosphor layer to be formed) as necessary.

In the illustrated example, the light detection panel S rotates so as to rotate. However, the present invention is not limited to this, and the rotation of the light detection panel S may be revolving or self revolving. .
Alternatively, in the present invention, the phosphor layer may be formed while reciprocating the light detection panel S in a straight line instead of rotating. In this case, it is preferable to arrange a plurality of crucibles 18 (evaporation sources) in a direction orthogonal to the reciprocating conveyance, or a crucible that is long in the orthogonal direction may be used.

A crucible 18 that is an evaporation source is disposed in the lower part of the vacuum chamber 12.
In addition, a shutter that is a shielding plate for shielding vapor of the film forming material that is discharged from the crucible 18 and travels toward the light detection panel S that is a film forming substrate, between the crucible 18 in the vertical direction and the substrate holder 36. 20 is arranged.

The crucible 18 is a known resistance heating crucible used in a vacuum deposition apparatus. That is, in the illustrated vapor deposition apparatus 10, the film forming material of the phosphor layer is heated / melted / evaporated by resistance heating.
In the present invention, the heating method of the film forming material is not limited to resistance heating, and induction heating is possible as long as the film forming material can be heated and melted / evaporated at a vacuum degree of 0.1 to 10 Pa. All known heating means such as can be used.

The vapor deposition apparatus 10 in the illustrated example has only one crucible 18, but the present invention is not limited to this, and vacuum vapor deposition may be performed using a plurality of crucibles (evaporation sources).
Furthermore, the present invention provides a multi-source vacuum that heats / melts each film-forming material with different crucibles when a plurality of types of film-forming materials are used even in a single vacuum deposition in which all kinds of film-forming materials are put into the same crucible. Vapor deposition may be used. For example, in the case of an alkali metal halide phosphor represented by “CsI: Tl”, cesium iodide (CsI), which is a matrix component film forming material, and an activator component are formed. A mixture of the film material with thallium iodide (TlI) may be put into a crucible and heated / melted, or a single vacuum deposition may be performed, or cesium iodide and thallium iodide are heated with separate crucibles. / Two-source vacuum evaporation may be performed.
In the case of performing unitary vacuum deposition, in order to obtain a phosphor layer having a target composition, the concentration of the activator component to be introduced into the crucible 18 as an evaporation source is set to a desired value in the phosphor layer. It is preferable to make it higher than the active agent concentration. When a plurality of crucibles are used, each crucible may be heated by the same method or different methods.

A power source 22 for resistance heating is connected to the crucible 18. The power source 22 is controlled by the control means 24. Further, inside the crucible 18, a temperature measuring means 18a for measuring the temperature of the film forming material is arranged. The temperature measurement result by the temperature measuring means 18a is sent to the control means 24. The temperature measuring means 18a is not particularly limited, and all known temperature measuring means used in vacuum deposition or the like such as a thermocouple can be used.
The heating control method for the crucible 18 is not particularly limited, and various control methods used in vacuum deposition by resistance heating, such as a thyristor method, a DC method, a feedback method according to temperature measurement or evaporation measurement, a constant current method, and the like. Is available. In the case of performing the binary vacuum deposition, a different heating control method may be used, such as a feedback method for the base component and a constant current method for the activator component.
Note that the control means 24 does not only control the heating of the crucible 18 but also manages and controls the overall operation of the vapor deposition apparatus 10, and the shutter moving means 26, which will be described later, has a power supply 22. Is started and heating of the film forming material by the crucible 18 is started, and when the temperature of the film forming material reaches the melting point of the film forming material + 10 ° C., information to that effect is sent. This will be described in detail later.

The shutter 20 is a shielding plate for shielding the vapor of the film forming material (phosphor) that evaporates in the crucible 18 and travels toward the light detection panel S that is the film forming substrate. In the present invention, the shutter 20 may basically be a normal shutter used in various vacuum vapor deposition apparatuses, except that a size (length) to be described later is specified. The shutter 20 will be described in detail later.
In addition, the shutter moving means 26 is a film-forming material from the crucible 18 toward the light detection panel S at the upper part of the crucible 18 shown by a solid line in FIG. 1 before and after the formation of the phosphor layer on the light detection panel S. When the phosphor layer is formed on the light detection panel S, the shutter 20 is positioned at a shielding position that shields the vapor of vapor (hereinafter referred to as “shutter 20 is closed”). The shutter 20 is located at an open position that does not block the vapor of the film-forming material toward the detection panel S (hereinafter referred to as “shutter 20 is opened”).

The method of moving the shutter 20 by the shutter moving means 26 is not particularly limited, and various known plate-like moving means can be used.
Further, the movement of the shutter 20 to the open position and the shielding position by the shutter moving means 26 is not limited to the horizontal sliding movement as in the illustrated example, but the film forming material vapor from the crucible 18 toward the light detection panel S. Can be moved to a position where the vapor of the film forming material from the crucible 18 toward the light detection panel S is not shielded at all, various movement methods such as movement by swinging and movement by rotation can be used. .

Here, in the vapor deposition apparatus 10 that implements the manufacturing method of the present invention, the shutter moving means 26 starts heating the film forming material with the crucible 18, and the temperature of the film forming material reaches a predetermined temperature. After a predetermined time elapses, the shutter 20 is opened to start forming a phosphor layer (vacuum deposition) on the light detection panel S, and before the predetermined time elapses, the shutter 20 is closed to form a phosphor layer. Exit.
Specifically, the heating of the film forming material is started, and the film forming material in the crucible 18 starts from the time when the temperature of the film forming material reaches the melting point of the film forming material + 10 ° C. (hereinafter referred to as the reference temperature). The time to evaporate all is T, and after 0.1T has elapsed from the time when the film forming material reaches the reference temperature (including 0.1T), the shutter 20 is opened and the formation of the phosphor layer is started. In addition, before 0.9 T elapses from the time when the film forming material reaches the reference temperature (including 0.9 T), the shutter 20 is closed to complete the formation of the phosphor layer. That is, the time when the film forming material reaches the reference temperature is set to 0.0T, and after 0.1T or more has elapsed, the shutter 20 is opened to start the formation of the phosphor layer, and before 0.9T elapses. Then, the shutter 20 is closed to complete the formation of the phosphor layer.

In the present invention, preferably, after 0.2 T or more has elapsed from the time when the film forming material has reached the reference temperature, more preferably, after 1/3 T or more has elapsed, and particularly preferably, after 0.5 T or more has elapsed. Then, the shutter 20 is opened and the formation of the phosphor layer is started. Thereby, formation of a fluorescent substance layer can be started in the state where evaporation was stabilized more, and a more suitable fluorescent substance layer can be formed.
In the present invention, it is preferable that 0.8T elapses from when the film forming material reaches the reference temperature, more preferably 2 / 3T elapses, and particularly preferably 0.5T elapses. Before the time elapses, the shutter 20 is closed to finish the formation of the phosphor layer. Thereby, the formation of the phosphor layer can be completed in a state where evaporation is more stable, and a more suitable phosphor layer can be formed.

By having such a configuration, the present invention starts forming the phosphor layer on the light detection panel S after the evaporation of the film forming material is stabilized, and reduces the film forming material in the crucible 18. Thus, before the evaporation becomes unstable, the formation of the phosphor layer is finished.
Thereby, it is possible to suitably prevent adhesion of foreign matters at the start of vapor deposition, and to prevent deterioration of properties due to adhesion of foreign matters or bumping due to abnormal evaporation at the end of vapor deposition. This will be described in detail later.

In the present invention, basically, when the temperature of at least a part of the film forming material in the crucible 18 reaches the melting point of the film forming material + 10 ° C., the film forming material becomes the reference temperature. Good. That is, the temperature may be measured at one point in the crucible 18 (preferably the central portion near the bottom of the crucible 18) by the temperature measuring means 18a in the crucible 18.
Alternatively, in consideration of the temperature distribution of the film forming material, the temperature is measured at a plurality of points in the crucible 18 in order to start the vapor deposition after the evaporation is further stabilized, and all the points or the average value is the film forming material. When the temperature reaches the melting point of + 10 ° C., the film forming material may reach the reference temperature. As a preferable example in the case of measuring the temperature at a plurality of points, there are a central portion near the bottom of the crucible 18 and two points near the bottom near the crucible side wall which is the farthest from the center.

Further, when the vapor deposition apparatus 10 has a plurality of crucibles, it is assumed that the film forming material becomes the reference temperature when the temperature of the film forming material of all the crucibles becomes the melting point of the film forming material + 10 ° C. Is preferred. However, the present invention is not limited to this. For example, when the temperature of the film forming material of the predetermined number of crucibles 18 reaches a temperature of the melting point of the film forming material + 10 ° C. It may be the temperature. That is, when there are a plurality of crucibles 18, the determination when the film forming material reaches the reference temperature may be appropriately set according to the apparatus configuration, the number of crucibles, and the like.
In addition, in the case of performing multi-source vacuum deposition in which a plurality of film forming materials are put into different crucibles (evaporation sources), the temperature reaches the reference temperature when the temperatures of all the film forming materials reach the melting point + 10 ° C. Alternatively, when the content in the phosphor layer is overwhelmingly different, such as the base component and the activator component, the reference temperature is reached when the temperature of the mass component reaches the melting point + 10 ° C. It may be.
In addition, when a plurality of film forming materials are put into one crucible, the reference temperature may be set corresponding to the melting point of the mixture of the two, or the reference temperature corresponding to the larger amount of film forming material. May be set, and the reference temperature may be set corresponding to the film forming material having a high melting point. These may be appropriately selected according to the amount ratio and characteristics of the film forming materials to be mixed.
Furthermore, instead of directly measuring the temperature of the film forming material in the crucible, the temperature of the outer wall surface of the crucible may be measured to change to the temperature measurement of the film forming material.

In the illustrated vapor deposition apparatus 10, the time T from when the temperature of the film forming material reaches the reference temperature until all the film forming material in the crucible 18 evaporates is the heating condition, the heating sequence, and the crucible 18. According to the amount of the film forming material to be filled in, it is necessary to know in advance by simulation or experiment, and to input to the control means 24, the shutter moving means 26, etc. and store them.
Further, as described above, after the power source 22 is driven, the control unit 24 indicates that the temperature of the film forming material becomes the reference temperature based on the temperature measurement result by the temperature measuring unit 18 (the temperature of the film forming material is the melting point + 10 When the temperature reaches 0 ° C.), information to that effect is sent to the shutter moving means 26. In accordance with this information, the shutter moving unit 26 opens the shutter 20 at a predetermined time when 0.1 T or more has elapsed from the time when the film forming material has reached the reference temperature, so that the shutter 20 is moved to the light detection panel S. The formation of the phosphor layer is started by closing the shutter 20 at a predetermined time before 0.9 T has elapsed from the time when the film forming material reaches the reference temperature after the formation of the phosphor layer is started. finish.

The crucible 18 opens the shutter 20 after 0.1 T has elapsed from the time when the film forming material has reached the reference temperature with respect to time T, and closes the shutter 20 before 0.9 T has elapsed. However, it is necessary to fill with a sufficient film forming material capable of forming a phosphor layer having a target thickness.
Here, as a matter of course, when the filling amount of the film forming material into the crucible 18 changes, the time T also changes. That is, in the present invention, the opening / closing timing of the shutter 20 for forming the phosphor layer having the target thickness is adjusted / set by adjusting the filling amount of the film forming material into the crucible 18. be able to. Similarly, since the time T can be changed even if the heating conditions are changed, the timing of opening / closing the shutter 20 for forming the phosphor layer having the target thickness can be adjusted by adjusting the heating conditions. Can be adjusted / set.

Moreover, in the vapor deposition apparatus 10 which implements the manufacturing method of this invention, the shutter 20 is
W ≧ 1.4 × (Prospect surface length + Δx)
The length W in the direction parallel to the phosphor layer forming surface of the light detection panel S that satisfies the above is satisfied.

Here, for example, as schematically shown in FIG. 2, the prospective surface is the upper surface of the phosphor layer forming surface of the light detection panel S held by the substrate holder 36, and the vapor discharge port of the crucible 18 as the evaporation source ( Assuming a solid (in this example, a quadrangular frustum) that has a side surface connecting the periphery of the top surface and the periphery of the bottom surface, this solid is This is a surface cut parallel to the phosphor layer forming surface (upper surface) at the shielding position of the film forming material vapor by the shutter 20.
On the other hand, Δx indicates that the shutter 20 is moved from the open position where the steam from the crucible 18 is not shielded, shown by the dotted line in FIG. 1, to the shield position where the steam from the crucible 18 toward the light detection panel S is shown as a solid line in FIG. This is a mechanical error (hereinafter referred to as error Δx) of the position of the shutter 20 at the shielding position when moved.

Note that, as shown in the illustrated example, when the light detection panel S that is a film formation substrate is rotated (spin, revolve, self revolve), and when the light detection panel S is reciprocally conveyed linearly, the light detection panel Corresponding to the entire surface of S trajectory (all areas), a prospective surface may be set assuming a solid composed of the upper surface, the lower surface and the side surface, with the surface connecting the outermost track as the upper surface. That is, when the substrate S is rotated as in the illustrated vapor deposition apparatus 10, the upper surface may be a circle.
Further, when a plurality of light detection panels S are held on the substrate holder 36, a surface including all the light detection panels S so as to be inscribed is assumed, and the surface is assumed to be the upper surface. do it.

Furthermore, when it is difficult to assume a three-dimensional structure in which the light detection panel S is the upper surface and the steam discharge port of the crucible 18 is the lower surface, depending on the shape and arrangement of the vapor discharge ports of the light detection panel S and the crucible 18, and When the steam outlet is significantly smaller than the size of the light detection panel S, the distance between the crucible 18 and the shutter, or the distance between the crucible 18 and the light detection panel S (when it can be regarded as a point evaporation source). The prospective surface may be set assuming a cone whose apex is the center of the steam outlet.
For example, in the example shown in FIG. 2, a square pyramid having the center of the crucible 18 as the apex and having the light detection panel S as a bottom surface or a cone having the rotating light detection panel S as a bottom surface is assumed. The quadrangular or circular prospective surface may be set by cutting the square pyramid or cone in parallel with the bottom surface at the shielding position.

As is clear from the above equation, in the present invention, the shutter at the shielding position is positioned on the prospective surface indicating the region of the film forming material vapor from the crucible 18 toward the light detection panel S (film deposition substrate) at the shielding position by the shutter 20. 20 before the formation of the phosphor layer and after the end of the formation using the shutter 20 having a length of 1.4 times the length of the surface including the error Δx. The film forming material vapor is shielded.
According to the present invention, by using such a shutter, it is possible to more reliably prevent unnecessary film forming material from adhering to the light detection panel S when the phosphor layer is not formed.

As described above, in a CR using an IP (Imaging Plate) having a stimulable phosphor layer, a radiation image is taken (accumulated and recorded) on the IP, and then excitation light is incident on the IP. Therefore, a radiographic image is obtained by photoelectrically reading the photostimulated luminescence emitted by the photostimulable phosphor in accordance with the captured radiographic image.
Here, the reading of the radiation image photographed by the IP usually reads excitation light by entering excitation light on the surface of the photostimulable phosphor layer, that is, on the side opposite to the film formation substrate. Therefore, in order to obtain an appropriate radiation image, the surface properties of the phosphor layer are important.

In contrast, in radiographic imaging using an indirect FPD, radiation transmitted through the subject is incident from the surface of the FPD (that is, the surface of the phosphor layer (opposite to the photodetection panel S that is the film formation substrate)). The light emission (fluorescence) of the phosphor layer due to the incidence of radiation is photoelectrically converted and read by the light detection panel S serving as a film formation substrate, thereby obtaining a radiation image. That is, in the indirect type FPD, radiation is incident from the deposition end surface of the phosphor layer, and light emission, that is, reading of a radiation image is performed from the deposition start surface (surface of the film formation substrate) of the phosphor layer.
Therefore, in the indirect type FPD, when there are foreign substances, phosphors with abnormally grown crystals, phosphors that are unnecessarily attached, etc. between the phosphor layer and the light detection panel S, the phosphor The light emitted from the layer is blocked, absorbed, refracted, diffusely reflected, etc., and an accurate radiation image cannot be obtained.
That is, when the indirect type FPD phosphor layer is formed by vacuum deposition, the property of the deposition start surface is so important that it cannot be compared with ordinary vacuum deposition. It is necessary to avoid adhesion of unnecessary phosphors and the like.

In particular, in the present invention, the phosphor layer is formed by vacuum deposition in a medium vacuum of 0.1 to 10 Pa. As described above, by forming the phosphor layer in such a medium vacuum, it is possible to form a phosphor layer formed of very good columnar crystals.
On the other hand, when vacuum deposition is performed with medium vacuum, it is necessary to make the distance between the film-forming substrate and the evaporation source (photodetection panel S and crucible 18) closer to that of vacuum deposition with a normal degree of vacuum. There is. For this reason, bumped film formation materials and unnecessary film formation materials are likely to adhere during the dissolution of the film formation materials before the start of the phosphor layer formation (before the start of vapor deposition) and in the evaporation stabilization process.

  In addition, in the indirect FPD, not only the vapor deposition start surface but also the properties of the surface of the phosphor layer on which the radiation is incident (that is, the vapor deposition end surface) are of course important. If there are abnormally grown phosphor crystals or the like, radiation is blocked or scattered by these, and an accurate radiographic image of the subject cannot be obtained.

On the other hand, according to the present invention, the shutter 20 having a size in which the length W in the direction parallel to the light detection panel S satisfies the above-mentioned “W ≧ 1.4 × (length of prospective surface + Δx)” is used. Thus, in the step of melting and evaporating the film forming material before starting to deposit the phosphor layer, the vapor evaporating from the crucible 18 (evaporation source) toward the light detection panel S that is the film forming substrate, Foreign matter due to bumping or the like, which is likely to occur before the evaporation of the film forming material is stabilized, can be reliably shielded by the shutter 20. Therefore, it is possible to prevent unnecessary phosphors and foreign matters from adhering to the light detection panel S before starting the vapor deposition.
Further, in the present invention, T is defined as the time from when the heating of the crucible 18 is started until the film forming material reaches the reference temperature until the film forming material filled in the crucible 18 evaporates. After 0.1 T has elapsed from when the temperature reaches the reference temperature, the shutter 20 is opened, and vapor deposition of the phosphor layer on the light detection panel S is started. Therefore, heating / melting of the film-forming material in the crucible 18 and deposition can be started after the film-forming material from the crucible 18 is completely stabilized, so that the high quality in a very stable state from the deposition start surface. A simple phosphor layer can be formed. Moreover, even if the time from the start of heating to the start of vapor deposition is lengthened for the purpose of more stable evaporation, etc., the phosphor that adheres to the light detection panel S can be prevented by the shutter.

Therefore, according to the present invention, the film forming material is very evaporated on the extremely clean photodetection panel in which the adhesion of foreign matters and the like is prevented by the synergistic effect of the size of the shutter 20 and the formation start timing of the phosphor layer. Since stable vapor deposition can be started, it is strongly required for FPD as described above, and on the vapor deposition start surface (the surface of the light detection panel S), generation of foreign substances, unnecessary phosphors, abnormal crystals of phosphors, etc. Therefore, a phosphor layer having very good properties can be stably formed.
That is, according to the present invention, the cleanliness of the deposition start surface, which is strongly required in FPD, is sufficiently ensured, point defects caused by foreign matter etc. on the deposition start surface are greatly reduced, and An FPD having a good columnar crystal phosphor layer obtained by vacuum deposition under vacuum and capable of obtaining a radiation image with high sensitivity and sharpness can be stably produced.

Further, when the amount of the film forming material in the crucible 20 is reduced, it becomes difficult to control heating and the deposition becomes unstable as compared with a state where a sufficient amount of the film forming material is filled. In addition, bumping due to partial heating of the film forming material, denaturation due to overheating, and the like occur, and abnormal crystals and foreign matters adhere to the phosphor layer.
On the other hand, in the present invention, the shutter 20 is closed before 0.9 T has elapsed from the time when the film forming material reaches the reference temperature, and the formation of the phosphor layer on the light detection panel S is completed. Therefore, the film formation material is sufficiently present in the crucible 18, and the formation of the phosphor layer is completed in a state where the evaporation of the film formation material and the heating of the film formation material in the crucible are stable. Therefore, according to the present invention, the film formation end surface (the upper surface of the phosphor layer), which is the radiation incident surface, can be in a very clean state free of foreign matters, etc., so that the radiation shielding, irregular reflection, etc. caused by the foreign matters etc. Thus, an FPD capable of obtaining an image of high-quality radiation that prevents the image quality deterioration factor can be stably produced.

  In the present invention, basically, the shutter 20 is assumed to be a surface inscribed in the prospective surface, and a length obtained by adding an error Δx to the length of this surface and multiplying it by 1.4 (that is, “1.4” X (surface length + Δx) ") or more.

As an example, FIG. 2 schematically shows an example in which a circular light detection panel S and a crucible 18 having a square steam outlet are used, and a circular shutter 20 is disposed at a height of d. 2A is a front view (viewed from the same direction as FIG. 1), and FIG. 2B is a top view.
In this case, a quadrangular frustum is assumed in which the light detection panel S is the upper surface and the steam outlet of the crucible 18 is the lower surface.
This quadrangular frustum is located at a position d from the vapor outlet of the crucible 18 (the upper surface of the crucible 18 in the illustrated example), which is a shielding position by the shutter 20, and is the phosphor layer forming surface of the light detection panel S, that is, the quadrangular frustum A circle with a radius “r” inscribed in the square f is assumed with this cut plane (square f) as a prospective plane (alternate long and short dash line). That is, the diameter 2r of the square diagonal line, that is, the circle having the radius r is the length of the prospective surface. Next, an error Δx is added to the circle of radius r to assume a concentric circle with a diameter of “2r + Δx” (two-dot chain line). Furthermore, this “2r + Δx” may be multiplied by 1.4 to obtain a concentric circular shutter 20 having a diameter of “1.4 × (2r + Δx)” or more, which is indicated by a broken line in the drawing.

Of course, the shape of the shutter 20 is not limited to a circle.
For example, in the example shown in FIG. 2, when a square shutter similar to the square f that is the prospective surface is used, the error Δx is added to the length L of the side of the square f, and multiplied by 1.4, What is necessary is just to make it the square shutter 20 whose length of one side whose center coincides with the square f is “1.4 × (L + Δx)” or more.
Further, when the prospective surface has a rectangular shape, if it is a circular shutter, as in the example shown in FIG. 2, assuming a circle with a radius r inscribed in the rectangle, the diameter 2r of this circle is Δx Is added to 1.4 to obtain a circular shutter 20 having a radius equal to or greater than “1.4 × (2r + Δx)”. When a rectangular shutter having the same shape as the prospective surface is used, the error Δx is added to both the long side La and the short side Lb of the prospective surface and multiplied by 1.4, and the long side becomes “1.4 × A rectangular shutter 20 whose center is equal to or greater than (La + Δx) ”and whose short side is equal to or greater than“ 1.4 × (Lb + Δx) ”may be used.
Further, when the shutter 20 has an elliptical shape, similarly, assuming an ellipse inscribed in the prospective surface, a major axis obtained by adding an error Δx to the major axis and minor axis and multiplying each by 1.4. In addition, an oval shutter 20 having a short axis may be used.

  The shutter 20 is not limited to such a circle, square, rectangle, and ellipse, and various shapes can be used depending on the shape of the vapor deposition apparatus 10 and the crucible 18, the shape of the light detection panel S, and the like. is there.

  In the present invention, when the vapor deposition apparatus 10 has a plurality of crucibles 18 (evaporation sources), as an example, first, a prospective surface (hereinafter referred to as a “sub-probability” for each crucible 18 in the same manner as before. ”)” And a prospective surface that includes all sub-prospect surfaces (hereinafter referred to as “main prospective surface” for convenience), and the length of this main prospective surface is set as described above. By adding the error Δx, the shutter 20 may have a length multiplied by 1.4, that is, a length W (size) of “W ≧ 1.4 × (length of main prospective surface + Δx)”.

  Or as shown in FIG. 3, the cone which connects the two crucibles 18a and the crucible 18b, and the light detection panel S is set, and with respect to the crucible 18 arrange | positioned on the outermost side, the light detection panel S is made into a bottom face. A cone which sets a cone to be obtained, obtains an intersection C of a line connecting the crucible 18 (the center thereof) and the end of the light detection panel S, and a cone having the intersection C as a vertex and the light detection panel S as a bottom surface. In this case, the conical body may be cut at a shielding position by the shutter 20 to set a prospective surface, and the size and shape of the shutter 20 may be set in the same manner.

  Further, when a plurality of crucibles are used, there is no limitation to the configuration having one shutter that is common to all the crucibles, and for each crucible according to the device configuration or the like, the above expression “W ≧ 1. 4 × (prospect surface length + Δx) ”may be provided, and a shutter that satisfies the above equation by setting a main main promising surface common to a plurality of crucibles and the crucible corresponding to one crucible. A shutter that satisfies the equation may be mixed.

In the present invention, the shielding position by the shutter 20 (d in FIG. 2A) is not particularly limited, but the distance from the crucible 18 (evaporation source) or from the light detection panel S which is a film formation substrate. It is preferable that the position where the distance is equal to or less than the mean free path of the film forming material vapor in the degree of vacuum in the shutter shielding state is the shielding position of the shutter 20.
In the present invention, a plurality of shutters S may be provided between the light detection panel S and the crucible 18. In this case, it is of course preferable that all the shutters 20 have a length W that satisfies the above-mentioned “W ≧ 1.4 × (prospect surface length + Δx)”. The two shutters 20 should just satisfy | fill the said Formula.

  Hereinafter, the present invention will be described in more detail by explaining the action of forming the phosphor layer on the light detection panel S by the vapor deposition apparatus 10.

  First, the vacuum chamber 12 is opened, the photodetection panel S as a film formation substrate is attached to a predetermined position of the substrate holder 36, and the crucible 18 is filled with a predetermined amount of film formation material. As an example, assuming that the phosphor layer made of the phosphor represented by “CsI: Tl” is formed, in the illustrated example, the phosphor layer is formed by unified vacuum deposition, so cesium iodide, thallium iodide, The crucible 18 is filled with a predetermined amount using a mixture mixed at a predetermined ratio according to the composition of the target phosphor as a film forming material.

In this example, heating is controlled so as to keep the crucible 18 at a predetermined temperature by a feedback method (control) using the temperature measurement result by the temperature measuring means 18a.
Under this heating control condition, when the crucible 18 is filled with the predetermined amount of film forming material, the time T from when the temperature of the film forming material reaches the reference temperature until the film forming material completely evaporates after the start of heating. Are known in advance through experiments or simulations. Furthermore, a phosphor layer having a predetermined film thickness can be formed according to the time T, and the shutter 20 is opened (deposition start) after 0.1 T from the time when the temperature of the film forming material becomes the reference temperature. The opening / closing timing of the shutter 20 from the time when the film forming material reaches the reference temperature is the time when the shutter 20 is closed (film formation end) before 0.9 T from the time when the temperature of the film forming material reaches the reference temperature. An experiment or simulation is performed and set in advance, and input / set to the shutter moving means 26 and the control means 24 is performed.

When the light detection panel S is attached to the substrate holder 36 and a predetermined amount of film forming material is filled in the crucible 18, the vacuum chamber 12 is closed and the vacuum pump is driven to evacuate the vacuum chamber 12 to make a vacuum. In this state, the shutter 20 is located at a shielding position indicated by a solid line in FIG.
Preferably, once the inside of the vacuum chamber 12 is set to a high vacuum (for example, about 8 × 10 ⁻⁴ Pa), an inert gas such as an argon gas is introduced from the gas introduction means 30 while continuing the evacuation, and the vacuum is kept. The pressure in the chamber 12 is set to a target vacuum degree of medium vacuum (0.1 to 10 Pa).

When the inside of the vacuum chamber 12 reaches a predetermined degree of vacuum, the control unit 24 drives the power source 22 to start energization of the crucible 18, that is, heating of the film forming material, and the temperature measuring unit 18a supplies the film forming material. Start acquiring temperature measurement results.
At the same time, the rotation drive source 32 is driven to start the rotation of the substrate holder 36, that is, the light detection panel S that is the film formation substrate. If necessary, the temperature of the film formation substrate and the phosphor layer being formed may be controlled by heating the light detection panel S with the sheath heater 36b. Further, the rotation of the light detection panel S may be just before the shutter 20 is opened.

After starting the heating of the film forming material, when the temperature of the film forming material measured by the temperature measuring unit 18a becomes the reference temperature, the control unit 24 sends information to that effect to the shutter moving unit 26. The shutter moving means 26 indicates the shutter 20 by a dotted line from the shielding position indicated by the solid line when the shutter opening time set after 0.1 T from the time (0.0T) when the film forming material reaches the reference temperature. Moving to the open position (opening the shutter), the formation (vapor deposition) of the phosphor layer on the light detection panel S is started.
The film formation rate is not particularly limited, and may be determined as appropriate according to the type of phosphor, the film formation method, the performance of the film formation apparatus, and the like. Specifically, about 0.5 to 20 μm / min is preferable.
Further, there is no particular limitation on the thickness of the phosphor layer, and the layer thickness capable of obtaining sufficient light emission may be appropriately determined according to the use of the FPD and the type of the phosphor, but preferably 50 μm. ˜1500 μm, especially about 200 μm to 1000 μm.

  Here, in the present invention, the shutter 20 has a length W that satisfies the above-mentioned “W ≧ 1.4 × (probable surface length + Δx)”, and therefore evaporation of the film forming material starts after heating is started. Even if bumping or the like occurs, they do not adhere to the light detection panel S, and the surface of the light detection panel S is kept clean. In addition, after 0.1 T has elapsed from the time when the film forming material reaches the reference temperature, the shutter 20 is opened and the formation of the phosphor layer is started, so that the evaporation of the film forming material is sufficiently stable. After all, an appropriate phosphor layer free from deterioration due to bumping, abnormal evaporation or the like can be formed from the deposition start surface.

When the formation of the phosphor layer is started and the shutter closing time set before 0.9 T from the start of heating is reached from the time when the film forming material reaches the reference temperature as described above, the shutter moving unit 26 The shutter 20 is moved from the open position indicated by the dotted line to the shielding position indicated by the solid line (the shutter is closed), and the formation of the phosphor layer on the light detection panel S is completed.
At the same time, the control unit 24 stops driving the power source 22 and finishes heating the film forming material. In addition, air or an inert gas is introduced from the gas introduction means 30 to return the inside of the vacuum chamber 12 to atmospheric pressure.

In this manner, the shutter 20 is closed, that is, the formation of the phosphor layer is completed before 0.9 T elapses, whereby the vapor deposition is completed with a sufficient amount of film forming material remaining in the crucible 18. Therefore, it is possible to form an appropriate phosphor layer without deterioration due to bumping or abnormal heating up to the film formation end surface.
Further, even if the heating is stopped, evaporation of the film forming material from the crucible 18 continues for a while. However, according to the present invention, since the shutter 18 has the predetermined size, this vapor is also reliably generated by the shutter 18. After the formation of the phosphor layer is closed, no extra phosphor adheres.

After the formation of the phosphor layer is completed, when the light detection panel S is cooled to a predetermined temperature, the vacuum chamber 12 is opened, the light detection panel S on which the phosphor layer is formed is taken out, and if necessary, Heat treatment (annealing) of the phosphor layer is performed. In the case where the vapor deposition apparatus 10 includes a substrate heating means such as a sheath heater 36b as shown in the drawing, the light detection panel S is not taken out and the heat treatment is performed in the vacuum chamber even after the cooling is completed. May be.
The heat treatment conditions for the phosphor layer are not particularly limited. As an example, under an inert atmosphere such as a nitrogen atmosphere, 50 to 600 ° C., particularly 100 to 300 ° C., 1/6 hour, A heat treatment of 0.5 to 3 hours is preferably exemplified.

  In the above example, the shutter 20 is of a predetermined size having a length W that satisfies “W ≧ 1.4 × (prospect surface length + Δx)”. The phosphor of the present invention, in which the formation of the phosphor layer is started after 0.1 T has elapsed from the time when the film material reaches the reference temperature, and the formation of the phosphor layer is terminated before 0.9 T has elapsed. The timing of the start / end of layer formation can be suitably used for vapor deposition apparatuses having various configurations.

As an example, as shown in FIG. 4, a horizontally disposed plate-like horizontal plate 50a, and a cylindrical frame portion 50b standing downward from the periphery (or side end surface) of the horizontal plate 50a The vacuum evaporation apparatus which has the shutter 50 which has this is illustrated. In this example, since the shutter 50 has the frame part 50b, it can prevent more suitably that the vapor | steam of film-forming material spreads in a horizontal direction.
In the shutter 50, the horizontal plate 50a and the frame portion 50b are independent from each other. When the shutter 50 is closed, the upper surface of the frame portion 50b is closed with the horizontal plate 50a as shown in FIG. The crucible 18 is surrounded by a frame portion 50b and is disposed at a position (shielding position) where the crucible 18 is covered from above, and the film-forming material vapor directed from the crucible 18 toward the photodetection panel S as a film-forming substrate is shielded. . At the time of opening, as shown in FIG. 4B, the horizontal plate 50a is moved in the horizontal direction in the same manner as the shutter 20, and the frame portion 50b is moved downward to form the film from the crucible 18 toward the light detection panel S. Move to an open position that does not block material vapor.

In the shutter 50 including the horizontal plate 50a and the frame portion 50b, the horizontal plate 50a has a length W that satisfies the above-mentioned “W ≧ 1.4 × (length of prospective surface + Δx)”. It is good.
Further, when using the shutter 50 including the horizontal plate 50a and the frame portion 50b, the crucible 18 is opened and closed depending on the positional relationship between the crucible 18 and the shutter 50 and the moving method of the shutter 50 for opening and closing. However, when the movement of the shutter 50 is not obstructed, the horizontal plate 50a and the frame portion 50b may be integrally formed.

  As shown in FIG. 5, the shutter opening / closing timing of the present invention is a housing-like shutter that seals the light detection panel S held by the substrate holder 36 together with the substrate holder 36 (sheath heater 36a). The present invention can also be suitably used for a vacuum deposition apparatus having 54.

Furthermore, as shown in FIG. 6, the shutter opening / closing timing of the present invention includes a sub-chamber 60 communicating with the vacuum chamber 12, and a shutter 72 that hermetically closes / opens the communicating portion between the vacuum chamber 12 and the sub-chamber 60. It can use suitably also for the vapor deposition apparatus which has.
In this vacuum vapor deposition apparatus, the shutter 72 is closed and the light detection panel S is positioned in the sub-chamber 60 before the vapor deposition is started. When the predetermined deposition start time set after 0.1 T is reached after the heating of the film forming material is reached, the shutter 72 is opened, the photodetection panel S is moved from the sub-chamber 60 to the vacuum chamber 12, and the substrate is moved. When the predetermined deposition end time set before 0.9 T is reached, the light detection panel S is removed from the substrate holder 36 and returned to the sub-chamber 60.

  Alternatively, instead of providing the sub-chamber 60 in the vapor deposition apparatus, the vacuum chamber is enlarged, and the light detection panel S (substrate rotating means 14) and / or the moving means of the crucible 18 are provided, before the formation of the phosphor layer and After the formation is completed, the light detection panel S or the crucible 18 is moved to a position where the vapor from the crucible 18 does not reach the light detection panel S, and the light detection panel S is placed immediately above the crucible 18 only when the phosphor layer is formed. It may be located.

  As mentioned above, although the manufacturing method of FPD of this invention was demonstrated in detail, this invention is not limited to the above-mentioned example, You may perform various improvement and a change in the range which does not deviate from the summary of this invention. Of course.

  Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention. Needless to say, the present invention is not limited to the following examples.

[Example 1]
The vapor deposition apparatus 10 shown in FIG. 1 was used, and the fluorescent substance layer was formed in this glass plate by using a glass plate as a film-forming board | substrate.
The vacuum chamber 12 was opened, and a rectangular glass plate having a thickness of 430 × 430 mm and a thickness of 1 mm was fixed / held on the substrate holder 36. The glass plate was held so that its center coincided with the substrate holder 36 and the rotation center.
On the other hand, 600 g of a raw material in which tantalum iodide and cesium iodide were mixed at a mixing ratio (molar ratio) of 0.001: 99.999 was charged in a resistance heating crucible 18 made of tantalum. The steam outlet of the crucible 18 is a rectangle having a size of 5 × 5 mm.
The distance (height h in FIG. 2) from the vapor outlet of the crucible 18 to the glass plate as the film formation substrate was 100 mm.

  On the other hand, a circular molybdenum plate having a diameter of 270 mm was prepared as the shutter 20 and mounted at a predetermined position related to the movement by the shutter moving means 26. The shielding position by the shutter 20 (height d in FIG. 2) was 30 mm from the steam outlet of the crucible 18.

As described above, the crucible 18 (the center thereof) is positioned vertically below the rotation center of the substrate holder 36. Further, the size of the glass plate as the film formation substrate is 430 × 430 mm, the size of the vapor outlet of the crucible 18 is 5 × 5 mm, the shielding position (height d) is 30 mm, and the distance (height h) between the crucible 18 and the glass plate. ) Is 100 mm, it can be almost regarded as a point evaporation source, and the prospective surface of this system is 129 × 129 mm.
Moreover, in this vapor deposition apparatus 10, the error Δx of the position of the shutter 20 at the shielding position was 10 mm.
Further, the size of the shutter 20 is 270 mm.
Therefore, 1.4 × (prospect surface length + Δx) = 1.4 × (129 × √2 + 10) ≈269.3, and the shutter 20 has a length “W ≧ 1.4 × (prospect surface). Length + Δx) ”.

After closing the vacuum chamber 12, the evacuation means is driven to evacuate the vacuum chamber 12, and when the inside of the vacuum chamber 12 reaches 8 × 10 ⁻⁴ Pa, the evacuation is continued and the gas introduction means Argon gas was introduced into the vacuum chamber 12 to adjust the pressure in the vacuum chamber 12 to 1 Pa.
Next, the power source 20 was driven to energize the crucible 18 to start heating the film-forming material and to start the rotation of the substrate holder 36. Further, the glass plate was heated to 100 ° C. by the sheath heater 36b. The heating of the crucible 18 was controlled by attaching a thermocouple as the temperature measuring means 18a to the crucible 18 and feeding back the measurement temperature result to be constant at 670 ° C.
Under this condition, after the start of heating, the time T from when the temperature of the film-forming material reaches the reference temperature (the melting point of cesium iodide + 10 ° C.) until the film-forming material completely evaporates is experimentally determined in advance. The time T was 160 min (minutes). Further, the film forming speed under these conditions was about 7 μm / min. Note that thallium iodide, which is an activator component, is a trace component in the film forming material, so the melting point can be ignored, and the melting point of the mixture can be regarded as the melting point of cesium iodide.

When 0.1 T passed after the temperature of the film forming material reached the reference temperature, the shutter 20 was opened and formation of the phosphor layer (CsI: Tl) on the glass plate was started.
Further, after the start of the formation (film formation) of the phosphor layer, when 0.9 T has elapsed from the time when the temperature of the film formation material becomes the reference temperature, the shutter 20 is closed to form the phosphor layer. finished. At the same time, the power source 22 was stopped, the heating of the crucible 18 and the rotation of the substrate holder 36 were also stopped, and then dry air was introduced from the gas introduction means 30 to bring the inside of the vacuum chamber to atmospheric pressure.

  When the temperature of the glass plate (phosphor layer) reaches a predetermined temperature, the vacuum chamber 12 is opened, the glass plate on which the phosphor layer is formed is taken out, and heated at a temperature of 200 ° C. for 2 hours in a nitrogen atmosphere. Processed.

[Examples 2 to 7]
Except that the formation of the phosphor layer was started at a time when 0.2 T had elapsed from the time when the film forming material reached the reference temperature (Example 2),
Except that the start of the formation of the phosphor layer was set to the time when 0.4 T had elapsed from the time when the film forming material became the reference temperature (Example 3),
Except that the formation start of the phosphor layer was set to a time when 0.5 T had elapsed from the time when the film forming material became the reference temperature (Example 4),
The formation of the phosphor layer is started when 0.2 T has elapsed from the time when the film-forming material has reached the reference temperature, and the end of formation of the phosphor layer is 0.8 T from the time when the film-forming material has reached the reference temperature. (Example 5)
The formation of the phosphor layer is started when 0.2 T has elapsed from the time when the film forming material has reached the reference temperature, and the end of formation of the phosphor layer is 0.7 T from the time when the film forming material has reached the reference temperature. (Example 6)
The formation of the phosphor layer is started when 0.2 T has elapsed from the time when the film-forming material has reached the reference temperature, and the end of formation of the phosphor layer is 0.5 T from the time when the film-forming material has reached the reference temperature. (Example 7)
In the same manner as in Example 1, a phosphor layer was formed on a glass substrate.

[Comparative Examples 1 to 3]
The formation start of the phosphor layer is defined as the time when the film forming material reaches the reference temperature (that is, 0.0T), and the end of the formation of the phosphor layer is defined as the time T (that is, 1) .0.0T) (Comparative Example 1)
The formation start of the phosphor layer is defined as the time when the film forming material reaches the reference temperature (0.0T), and the formation end of the phosphor layer is defined as the time when 0.95 T has elapsed from the time when the film forming material reaches the reference temperature. Except for (Comparative Example 2),
The formation of the phosphor layer is started when 0.05 T has elapsed from the time when the film forming material has reached the reference temperature, and the end of formation of the phosphor layer is set to 0.9 T from the time when the film forming material has reached the reference temperature. Except for the elapsed time (Comparative Example 3),
In the same manner as in Example 1, a phosphor layer was formed on a glass substrate.

[Comparative Example 4]
A phosphor layer was formed on a glass substrate in the same manner as in Example 5 except that the size of the shutter 20 was 182.4 mm (129 × √2), which had the same size as the length of the prospective surface.
[Comparative Example 5]
The glass substrate is the same as Example 5 except that the size of the shutter 20 is 231 mm in diameter (1.2 × (129 × √2 + Δx), which is 1.2 times the “expected surface length + Δx”). A phosphor layer was formed.

About each obtained phosphor layer, the point defect was investigated with the following method.
[Measurement of point defects]
In the dark room, an AgBr film was adhered in a close contact state to the non-phosphor layer forming surface of the glass substrate as the film formation substrate. This laminate was irradiated with 10 mR of X-rays from the phosphor layer side, and then the AgBr film was peeled off from the glass substrate and developed.
Ten areas of 100 cm ² were randomly selected from the developed AgBr film, the number of point defects visible in each area was counted, and the average of the ten positions was calculated (number of point defects). Moreover, the maximum size point defect (maximum point defect) was extracted from all the counted point defects, and the size [μm] was measured.
The results are shown in the table below.

なお、比較例４および比較例５は、シャッタのサイズが異なる。

Note that Comparative Example 4 and Comparative Example 5 differ in shutter size.

As shown in Table 1, with respect to time T from the time when the film forming material reaches the reference temperature to the end of evaporation, the fluorescence after 0.1 T has elapsed from the time when the film forming material reaches the reference temperature. According to the present invention in which the formation of the phosphor layer is started and the formation of the phosphor layer is terminated before 0.9T elapses, the number of point defects is smaller than that of the conventional phosphor layer formation method, And even if a point defect arises, a size is small. Therefore, according to the present invention, a high-quality planar radiation image detection panel that has good properties on both the start and end surfaces of vapor deposition and that provides high-quality radiation images with little image quality deterioration such as point defects can be stably obtained. Can be manufactured.
From the above results, the effect of the present invention is clear.

It is a conceptual diagram of an example of the (vacuum) vapor deposition apparatus which enforces the manufacturing method of the planar radiation image detector of this invention. (A) And (B) is a conceptual diagram for demonstrating an example of the manufacturing method of the planar radiographic image detector of this invention. It is a conceptual diagram for demonstrating another example of the manufacturing method of the planar radiographic image detector of this invention. (A) And (B) is a conceptual diagram for demonstrating an example of the manufacturing method of the planar radiation image detector to which the manufacturing method of the planar radiation image detector of this invention is applied. It is a conceptual diagram for demonstrating another example of the manufacturing method of the planar radiographic image detector to which the manufacturing method of the planar radiographic image detector of this invention is applied. It is a conceptual diagram for demonstrating another example of the manufacturing method of the planar radiographic image detector to which the manufacturing method of the planar radiographic image detector of this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 (Vacuum) Deposition apparatus 12 Vacuum chamber 14 Substrate rotating means 18 Crucible 18a Temperature measuring means 20, 50, 54, 62 Shutter 22 Power supply 24 Control means 26 Shutter moving means 30 Gas introducing means 32 Rotation drive source 34 Rotating shaft 36 Substrate holder 60 Subchamber

Claims (1)

A method for producing a planar radiation image detector, wherein a phosphor layer that emits light upon incidence of radiation is formed by vacuum deposition on a surface of a support in which photoelectric conversion elements are two-dimensionally arranged.
The phosphor layer was formed by vacuum deposition at a vacuum degree of 0.1 to 10 Pa, and the film forming material of the phosphor layer was heated, so that the temperature of the film forming material became the melting point of the film forming material + 10 ° C. 0.1 T has elapsed from the time when the temperature of the film forming material reaches the melting point of the film forming material + 10 ° C., where T is the time from when the film forming material accommodated in the evaporation source evaporates. Thereafter, the shutter for shielding the vapor discharged from the evaporation source is opened to start the deposition of the phosphor layer on the support, and the temperature of the film forming material is the melting point of the film forming material. Before 0.9T elapses from the time when the temperature reaches + 10 ° C., the shutter is closed, and the deposition of the phosphor layer on the support is completed,
Furthermore, a solid body having a phosphor layer forming surface of the support as an upper surface, a film forming material vapor outlet of the evaporation source as a lower surface, and a solid body having a side surface connecting the periphery of the upper surface and the periphery of the lower surface, The surface cut in parallel with the phosphor layer forming surface at the vapor shielding position by the shutter is a prospective surface, and when the mechanical position error at the time of opening and closing the shutter is Δx,
As the shutter, the following formula
W ≧ 1.4 × (Prospect surface length + Δx)
A method for producing a planar radiation image detector, wherein a shutter having a length W in a direction parallel to the phosphor layer forming surface is used.

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