JP2007262478A - Heating evaporator and multi-source deposition method - Google Patents

Abstract

The present invention provides a heating evaporation apparatus and a multi-source vapor deposition method capable of greatly improving uniform heatability.
A heating evaporation apparatus according to the present invention is a heating evaporation apparatus including a coil heater 52b and a container 52c, wherein a coil portion of the coil heater 52b and at least a side wall portion of the container are not in contact with each other, and The distance between the coil part and the side wall part of the container is substantially constant. In this apparatus, the thermal conductivity of the material constituting the container is large, the distance between the coil part of the coil heater 52b and the side wall part of the container is close, and the thickness of the side wall part of the container is uniform. It is desirable to be as thin as possible within a safe range. In addition, this apparatus can be used suitably for the multi-source vapor deposition method.
[Selection] Figure 1

Description

  The present invention relates to a heat evaporation apparatus, and more particularly to a heat evaporation apparatus that can be suitably used for heat evaporation of a sublimable material that is likely to cause bumping when heated and evaporated, and a multi-source deposition method using the heat evaporation apparatus.

  As the sublimable material here, a part of this radiation energy is accumulated when irradiated with radiation such as X-rays, and then when the excitation light such as visible light is irradiated, the phosphorescent light is emitted according to the accumulated radiation energy. The storage phosphors (stimulable phosphors) shown are known. Using this stimulable phosphor, a radiographic image of a subject such as a human body is temporarily recorded as a latent image on the stimulable phosphor layer, and this stimulable phosphor layer is irradiated with excitation light such as laser light. A radiographic image recording / reproducing system including a radiographic image recording apparatus and a radiographic image reading apparatus that generates luminescent light and photoelectrically detects the stimulated luminescent light to acquire an image signal representing a radiographic image of a subject is disclosed. Radiography) system.

  As a recording medium used in this radiographic image recording / reproducing system, a radiographic image conversion panel prepared by laminating a stimulable phosphor layer on a substrate is used. When the radiation image conversion panel is irradiated with erasing light, the residual radiation energy is released and the radiation image can be recorded again, and can be used repeatedly.

Further, as the radiation image reading device, for example, a line sensor that detects the stimulated emission light generated from the radiation image conversion panel upon irradiation with linear excitation light, and the line sensor with respect to the radiation image conversion panel. A transfer means for transferring in a direction orthogonal to the linear direction, and receiving a linear excitation light irradiation while transferring the line sensor relative to the radiation image conversion panel. There is known an apparatus for detecting a photostimulated luminescence generated from a conversion panel and acquiring a radiation image.
The radiographic image acquired as described above is subjected to shading correction or the like that removes the influence of uneven emission of the stimulated emission light, and is recorded on a film as a visible image or displayed on a high-definition CRT. Provided for diagnosis.

  As a technique related to shading correction used here, for example, a radiation image read from a radiation image conversion panel (that is, correction exposure) (ie, correction exposure). Radiological image) is stored in the apparatus in advance, and then a radiographic image (that is, a radiographic image of the subject) read from the radiographic image conversion panel in which the radiation is blown through the subject is obtained, and the correction is performed from the radiographic image of the subject. It is known that a radiographic image is subtracted to obtain a radiographic image (corrected radiographic image) from which the influence of shading is removed (see, for example, Patent Document 1, Patent Document 2, etc.).

  Incidentally, the stimulable phosphor, which is the main component of the radiation image conversion panel used in the CR system having the above-described excellent action, is generally manufactured by a vacuum deposition method. This stimulable phosphor is composed of a main component called a base material and a trace component called an activator. Usually, these two types of components are vaporized by evaporating them from separate containers. Manufactured by the vacuum deposition method used.

In this case, the base material and the activator generally use different types of evaporators because the amount used (evaporation amount) differs by about three orders of magnitude and the evaporation temperature differs considerably. There are many. As an example, a boat type or drum type (horizontal cylindrical) container by resistance heating method is used for evaporation of the base material (for example, CsBr), and an activator (for example, EuBr _x : x is usually 2 to 3). However, a vertical cylindrical container by the resistance heating method is used for evaporation of 2).

  The reason why the vertical cylindrical container is used for the evaporation of the activator is that the boat type or drum type container using the resistance heating method has a problem that deformation due to thermal stress is likely to occur particularly when exposed to a high temperature. In addition to this, in order to uniformly heat the activator, which is a trace component, it is also preferable to perform heating by radiant heat as much as possible (uniformity can be expected). Furthermore, if the heating becomes non-uniform, bumping may occur depending on the material, and there is a reason for avoiding this.

  By the way, as a cylindrical container by resistance heating method (generally referred to as a crucible since it is generally referred to as a crucible hereinafter), there are many known ones as disclosed in Patent Document 3, for example. It has been. These crucibles generally have a structure in which an electric heating coil (coil heater) is wound around the outside of a container made of various materials such as ceramics such as alumina, metals (platinum, tantalum, etc.), and carbon. .

JP 2000-013599 A Japanese Patent Application Laid-Open No. 01-086759 JP 2003-222472 A

  The problem with the crucible disclosed in Patent Document 3 is that the temperature in the container tends to be nonuniform in the crucible having such a structure. The reason for this is that a normal crucible of this type has a coiled heater formed of tungsten (W) or the like directly wound around the outer wall surface of the container (see FIG. 5 of Patent Document 3). This is because, of course, a temperature difference (temperature non-uniformity) occurs between a position where there is and a position where it does not.

  For example, this temperature difference (temperature non-uniformity) is a very important problem when producing a stimulable phosphor used for medical applications as described above, which requires high quality. That is, when temperature non-uniformity occurs in the crucible, problems such as evaporation becoming unstable or bumping occur, resulting in phosphor layer thickness unevenness and defect generation. As a result, the quality of the product deteriorates.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the problems based on the prior art, a heating evaporator capable of greatly improving uniform heating, and the heating The object is to provide a multi-source deposition method using an evaporation apparatus.

  In order to achieve the above object, a heating evaporation apparatus according to the present invention is a heating evaporation apparatus comprising a coil heater and a container, wherein the coil part of the coil heater and at least the side wall part of the container are in non-contact, and The distance between the coil part and the side wall part of the container is substantially constant.

  Here, in the heating evaporation apparatus according to the present invention, the material constituting the container has a high thermal conductivity (preferably, 50 W / mK or more), the coil portion of the coil heater, and the side wall of the container. The distance between the parts is close (preferably about 0.1 mm or more and 50 mm or less), and the thickness of the side wall part of the container is uniform and thin within a possible range (preferably 0 It is desirable that it is about 2 mm or more and 1 mm or less.

Moreover, the multi-source vapor deposition method according to the present invention uses a heating evaporation apparatus having the above-described characteristics,
(1) A multi-source vapor deposition method characterized by being used for heat evaporation of an evaporation component having the highest evaporation temperature in a multi-component vapor deposition apparatus, or
(2) It can be suitably put into practical use as a multi-source vapor deposition method characterized in that it is used for heat evaporation of an evaporation component having the smallest evaporation amount in a multi-component vapor deposition apparatus.

According to the present invention, there is a remarkable effect that it is possible to realize a heating evaporation apparatus capable of greatly improving the uniformity of heating.
More specifically, it is possible to realize a heating and evaporating apparatus that can be effectively used for the production of high-quality (homogeneous) products such that the evaporation state of the material to be evaporated in the container is stable and bumping does not occur. Has a remarkable effect.

  In addition, the heating evaporation apparatus which concerns on this invention can be used suitably for manufacture of the above-mentioned stimulable fluorescent substance using what is called a binary evaporation method. More specifically, it is suitably used for the purpose of stably and efficiently evaporating an activator added in a small amount with respect to a main component called a base material that evaporates in a relatively large amount in a boat-type or drum-type container. be able to.

  Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. Here, as an example, the temperature is measured inside an evaporation vessel (crucible) serving as a resistance heating source by using a linear transport (details will be described later) type vacuum deposition apparatus, and the crucible is determined according to the result. The case of controlling the heating of the film, that is, the evaporation amount (= deposition rate) of the film forming material will be described.

In FIG. 2, the conceptual diagram of the fluorescent substance sheet manufacturing apparatus which actualized the manufacturing method of the fluorescent substance layer which concerns on one Embodiment of this invention is shown. 2A is a front view, and FIG. 2B is a side view.
A phosphor sheet manufacturing apparatus (hereinafter referred to as a manufacturing apparatus) 10 shown in FIG. 2 separately forms a film forming material to be a phosphor (base material) and a film forming material to be an activator (activator). This is an apparatus for producing a (storable) phosphor sheet by forming a layer made of a stimulable phosphor (hereinafter also simply referred to as a phosphor layer) on the surface of the substrate S by binary vacuum evaporation to be evaporated.

Such a manufacturing apparatus 10 basically includes a vacuum chamber 12, a substrate holding / conveying mechanism 14, a heating evaporation unit 16, and a gas introduction nozzle 18.
In addition, it goes without saying that the manufacturing apparatus 10 may include various constituent elements of a known vacuum deposition apparatus such as a plasma generator (ion gun) as necessary. That is.

In the illustrated example, as a preferred example, cesium bromide (CsBr) as a phosphor component and europium bromide (EuBr _x (x is usually 2 to 3) as an activator component, Is preferably used as a film-forming material, and binary vacuum deposition is performed by resistance heating to form a phosphor layer made of CsBr: Eu, which is a storage phosphor, on the substrate S, and a phosphor sheet is formed. Make it. For this reason, an evaporation container (that is, a crucible) 50 serving as a resistance heating source for the phosphor and a crucible 52 serving as a heating source for the activator are disposed in the heating evaporation unit 16.

  Here, in order to simplify the drawing and clarify the configuration, although not shown, a resistance heating power source for resistance heating is connected to each crucible 52. For the same reason, only one location is shown in FIG. 2 (a) and illustration is omitted in FIG. 2 (b), but each crucible 50 has a thermocouple 58 (crucible 58), which will be described later, serving as temperature measuring means. 50), and the resistance heating power source 20 and the heating control means 22 are connected.

  In addition, the manufacturing apparatus 10 according to the present embodiment includes a gas introduction nozzle 18 that introduces an inert gas during film formation. Preferably, the vacuum chamber 12 is once evacuated to a high degree of vacuum and then evacuated. Introducing an inert gas such as argon from the gas introduction nozzle 18 while performing the vacuum degree of about 0.1 Pa to 10 Pa (particularly 0.5 to 3 Pa) in the vacuum chamber 12 (hereinafter referred to as medium vacuum), Under this vacuum, the phosphor layer is formed.

That is, the manufacturing apparatus 10 according to the present embodiment heats and evaporates film-forming materials (cesium bromide and europium bromide) by resistance heating in the heating evaporation unit 16, and the substrate holding and transporting mechanism 14 linearizes the substrate S. The phosphor layer is formed on the substrate S by vacuum deposition while being transported (hereinafter referred to as linear transport).
By forming the phosphor layer under a vacuum in which gas is introduced, the phosphor layer has a good columnar crystal structure, and a phosphor sheet having excellent image sharpness and stimulated emission characteristics is manufactured. can do.

A vacuum pump (not shown) is connected to the vacuum chamber 12.
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 manufacturing apparatus 10 for forming the phosphor layer described above, the ultimate vacuum in the vacuum chamber 12 is preferably 8.0 × 10 ⁻⁴ Pa or less.

The substrate holding and transporting mechanism 14 holds the substrate S and transports the substrate S along a linear transport path (hereinafter referred to as linear transport), and includes a substrate holding unit 30 and a transport unit 32. The
The conveying means 32 has a linear motor guide having a guide rail 34 and an engaging member 36 guided by the guide rail, a ball screw composed of a screw shaft 40 and a nut 42, a rotational drive source 44 of the screw shaft 40, etc. This is a known linear moving mechanism to be used.

  On the other hand, the substrate holding means 30 has an engagement member 48 that engages with the nut 42 of the ball screw and the engagement member 36 of the linear motor guide, and holds the substrate S at the lower end portion. And is linearly moved in a predetermined direction (the left-right direction in FIG. 2A and the direction perpendicular to the paper surface in FIG. 2B) by the conveying means 32.

  In the manufacturing apparatus 10 of the illustrated example, the substrate S is conveyed linearly in the predetermined direction by conveying the substrate holding means 30 by the conveying means 32 while the substrate S is held by the substrate holding means 30. In the illustrated example, the substrate S is transported in a straight line, and a plurality of evaporation sources are arranged in a direction perpendicular to the transport direction, thereby forming a phosphor layer with high uniformity of film thickness distribution. is doing.

  Here, the phosphor layer formed on the substrate is much thicker than a normal vacuum deposited film, and even if it is thin, it may be about 200 μm, usually about 500 μm, and if thick, it may exceed 1000 μm. Further, the activator and the phosphor are, for example, about 0.0001 / 1 to 0.01 / 1 in molar concentration ratio, and most of the phosphor layer is the phosphor.

  In general, as the film thickness is the same, the greater the number of passes through the upper portion of the heating evaporation unit 16, the higher the film thickness distribution uniformity. Therefore, the phosphor layer is reciprocated several times. Is preferably formed. In addition, the number of reciprocations may be appropriately determined according to the target film thickness of the phosphor layer, the target film thickness distribution uniformity, and the like. The conveyance speed may be appropriately determined according to the conveyance speed limit of the apparatus, the number of reciprocations, the target phosphor layer thickness, and the like.

A heating evaporation unit 16 is disposed below the vacuum chamber 12.
The heating evaporation unit 16 is a part that evaporates cesium bromide and europium bromide, which are film forming materials, by resistance heating. Although not shown for the same reason as above, a shutter that shields the vapor of the film forming material from the heating evaporation unit 16 (the crucible 50 and the crucible 52) is disposed on the heating evaporation unit 16.

  As described above, as a preferred embodiment, the manufacturing apparatus 10 performs binary vacuum deposition in which cesium bromide as a phosphor component and europium bromide as an activator component are independently heated and evaporated. Is. Therefore, a crucible 50 for cesium bromide (phosphor) and a crucible 52 for europium bromide (activator) are arranged in the heating evaporation unit 16.

  As shown in the schematic top view of FIG. 3, in the illustrated manufacturing apparatus 10, both the crucible 50 and the crucible 52 are provided in a direction orthogonal to the transport direction of the substrate S (hereinafter simply referred to as the transport direction). Are arranged. Note that the crucibles are insulated from each other by being arranged apart from each other or by inserting an insulating material.

  Also, both the crucible 50 and the crucible 52 have two rows of crucibles, and the rows of crucibles 50 are arranged so as to sandwich the two crucible 52 rows in the transport direction. Further, the crucibles 50 and the crucibles 52 adjacent to each other in the transport direction are arranged so as to coincide with the arrangement direction of the rows to make a pair, and the crucibles 50 and the crucibles 52 in different rows are staggered in the arrangement direction. Arranged in the same direction and filling the gaps in the same direction. This makes it possible to discharge steam uniformly in the arrangement direction.

  In the manufacturing apparatus 10 of the illustrated example, the entire surface of the substrate S is formed by linearly transporting the substrate S and arranging the resistance heating evaporation crucibles 50 and 52 in a direction perpendicular to the transport direction, as described above. Uniform exposure with the vapor of the film material enables formation of a phosphor layer with extremely high film thickness distribution uniformity.

  That is, the phosphor layer is formed by vacuum deposition while the substrate S is conveyed linearly, so that the moving speed on the surface of the substrate S (non-deposition surface) is made uniform over the entire surface, and a plurality of crucibles (resistance heating evaporation sources) are used. ) Are arranged in a straight line in the direction perpendicular to the transport direction, and the vapor deposition of the film forming material can be uniformly exposed on the entire surface of the substrate S with an extremely simple evaporation source arrangement, and the film thickness distribution is uniform. A highly fluorescent layer can be formed. In particular, in the medium-vacuum vacuum deposition as described above, there is a collision between the gas particles such as argon and the evaporated film forming material, so that the distance between the substrate and the crucible is larger than that in the ordinary high-vacuum deposition. Since it is necessary to narrow the film thickness, the film formation material reaches the substrate S before diffusing into the system, so that the effect is great.

  In addition, by having such a configuration, the activator component can be dispersed highly uniformly in the stimulable phosphor layer in both the surface direction and the thickness direction of the phosphor layer. A phosphor sheet excellent in uniformity such as emission characteristics and sensitivity can be obtained.

  The crucible 50 is formed of a refractory metal such as tantalum (Ta), molybdenum (Mo), tungsten (W) or the like, similar to a crucible used for vacuum vapor deposition by ordinary resistance heating, and is formed from an electrode (not shown). It is a crucible serving as a resistance heating source that generates heat when energized and heats / melts the filled film forming material to evaporate. The crucible 52 is made of the above-mentioned metal or ceramic, and is a crucible that is heated via a coil heater (not shown) and heats / melts the filled film forming material to evaporate.

As described above, in the stimulable phosphor, the activator and the phosphor are, for example, about 0.0005 / 1 to 0.01 / 1 in molar concentration ratio, and most of the phosphor layer is the phosphor. .
The crucible 52 for europium bromide (activator) with a small deposition amount is formed by closing the upper surface of a normal cylindrical crucible with a lid having a circular steam outlet. is there. Also, a cylindrical chimney (chimney) 52a having the same upper and lower opening surfaces is fixed to the vapor discharge port, and the vapor of the film forming material is discharged from the chimney 52a.

  As described above, although not shown, a coil heater is disposed in each crucible 52 at a certain distance from the crucible body, and a resistance heating power source is connected to the heater. Moreover, since an activator has little vapor deposition amount (evaporation amount), as an example, control of heating is performed by constant power control. Note that the heating control method of the crucible 52 is not limited to this, and various methods used in vacuum deposition by resistance heating, such as a thyristor method, a DC method, and a thermocouple feedback method, can be used.

  On the other hand, the crucible 50 for cesium bromide (phosphor) having a large deposition amount is a drum-type (cylindrical) large crucible. The crucible 50 has a slit-like steam outlet extending in the axial direction of the drum on the side surface of the drum. Further, a rectangular cylindrical chimney 50a having the same upper and lower opening surfaces is fixed to the vapor outlet, and similarly, the vapor of the film forming material is discharged from the chimney 50a. The crucible 50 is arranged with the axis of the drum aligned with the arrangement direction of the crucible 50. That is, the slit-shaped chimney 50 a is provided with the longitudinal direction aligned with the arrangement direction of the crucible 50.

  By having such a chimney (chimney-like steam discharge part), when bumping occurs due to local heating or abnormal heating in the crucible, it is possible to prevent the film forming material from being unexpectedly ejected from the crucible. Contamination of the substrate S can be prevented. In particular, in the above-described medium vacuum deposition, it is necessary to bring the substrate S and the evaporation source close to each other as described above.

  Here, the crucible 50 for cesium bromide measures the temperature in the crucible, and controls the evaporation amount (that is, the deposition rate) of the film forming material from each crucible according to the result of the measurement. The vacuum vapor deposition method is performed.

  FIG. 4 shows a schematic diagram of the crucible 50. 4, (a) is a top view, (b) is a partially cutaway front view (viewed from the same direction as FIG. 2 (b)), and (c) is a side view (FIG. 2 (a)). The figure seen from the same direction.

  As described above, the crucible 50 is a drum-type crucible, and a slit-like steam discharge port 50b that coincides in the axial direction is formed on the side surface of the drum, and the steam discharge port 50 has a rectangular tube whose upper and lower surfaces are open. A shaped chimney 50a is fixed. In the chimney 50a, a substantially Z-shaped rib 50c is disposed in order to support from the inside and improve the strength.

  Further, a shielding member 62 for preventing the bumped film forming material from being ejected is fixed in the crucible 50. The shielding member 62 is formed by folding a long rectangular plate material in the short direction to form a substantially T shape, and the attachment portion 62a is formed by vertically folding both longitudinal ends of the T-shaped upper portion upward. When viewed from above, the shielding member 62 is disposed in the crucible 50 (drum) so as to close the steam outlet 50 on the T-shaped upper surface, and the attachment portion 62a is fixed to the drum end surface from the inside.

Electrodes 60 are fixed to both end faces of the crucible 50 (drum).
The electrode 60 is connected to a resistance heating power source 20 (hereinafter simply referred to as a power source 20). The power source 20 is not particularly limited, and various types of power sources that are used for heat generation of a crucible serving as a resistance heating source in vacuum deposition by resistance heating can be used.

  In the illustrated example, a thermocouple 58 serving as temperature measuring means is inserted into the chimney 50a of the crucible 50 through the side surface (end surface in the slit extending direction). In order to prevent a temperature measurement error caused by a weak voltage from the power supply 20, the thermocouple 58 (its thermal contact) is preferably arranged so as not to contact the crucible 50. In the illustrated example, the thermocouple 58 is inserted from the end face of the chimney 50a in the slit extending direction, but the present invention is not limited to this, and the thermocouple 58 is inserted from the end face of the chimney 50a in the short slit direction. It is also preferable to insert a pair 58.

  In the crucible 50, the film forming material is filled so that the melted film forming material (melted evaporation source) does not come into contact with the shielding member 62 in a normal use state. Accordingly, the thermocouple 58 disposed in the chimney 50a does not contact the melt evaporation source. In the embodiment in which temperature measurement is performed without contact with the melt evaporation source, in order to perform highly accurate temperature measurement, the thermal contact of the thermocouple 58 is directly in contact with the film forming material vapor. Is preferred.

The heating control means 22 is connected to the thermocouple 58.
Here, the heating control means 22 is configured so that the temperature at the temperature measurement position becomes a predetermined temperature according to the temperature measurement result by the thermocouple 58 (that is, the evaporation amount of the film forming material becomes a predetermined rate). The power supplied from the power source 20 to the crucible 50 is controlled.

When the vapor deposition operation is started, the evaporation state is determined by measuring the temperature in the evaporation container. This may be performed using, for example, a graph showing the relationship between the temperature in the evaporation container and the evaporation rate, or a comparison table created based on the graph, which has been obtained in advance.
And the heating control means 22 observes the progress of vapor deposition continuously, and performs heating control according to the temperature measurement result by the thermocouple 58 so that the evaporation rate becomes a predetermined value.

  In the above-described embodiment, the heating evaporation control in the activator crucible 52 is constant power control. This is because the shape of the heat coil and the nature of using radiant heat make the temperature of the energized part higher than that of a boat-type container and the resistance value is likely to change, so constant current control and constant voltage control are constant. This is because electric power (that is, heat generation amount) may not be obtained. However, constant current control and constant voltage control can also be used depending on the properties of the coil, container, and activator material.

  Hereinafter, an operation of forming a phosphor layer (production of a phosphor sheet) on the substrate S by the manufacturing apparatus 10 according to the present embodiment will be described.

  First, the vacuum chamber 12 is opened, the substrate S is held on the substrate holding means 30 of the substrate holding and transport mechanism 14, cesium bromide is contained in all the crucibles 50, and europium bromide is contained in all the crucibles 52. Then, the shutter is closed and the vacuum chamber 12 is further closed.

Next, the vacuum evacuation means is driven to evacuate the vacuum chamber 12. When the inside of the vacuum chamber reaches, for example, 8 × 10 ⁻⁴ Pa, the evacuation is continued and the gas introduction nozzle 18 enters the vacuum chamber 12. Argon gas is introduced, the pressure in the vacuum chamber 12 is adjusted to, for example, 1 Pa, and the resistance heating power source is driven to energize all the crucibles 50 and crucibles 52 to heat the film-forming material. After the elapse of time, the rotation drive source 44 is driven to start transporting the substrate S, the shutter is opened, and formation of the phosphor layer on the surface of the substrate S is started.

  During film formation, the temperature in the crucible 50 is measured by the thermocouple 58 in all the crucibles 50, and the heating control means 22 controls the power supplied from the power source 20 to the crucible 50 according to the result. The evaporation rate is controlled by controlling the evaporation amount of the film forming material from the crucible 50.

  When the reciprocation of the predetermined number of times of linear conveyance set according to the thickness of the phosphor layer to be formed is completed, the linear conveyance of the substrate S is stopped, the shutter is closed, the resistance heating power is turned off, and the gas The introduction of the argon gas by the introduction nozzle 18 is stopped, dry nitrogen gas or dry air is introduced, the inside of the vacuum chamber 12 is brought to atmospheric pressure, then the vacuum chamber is opened, and the substrate S on which the phosphor layer is formed, that is, The produced phosphor sheet is taken out.

  In addition, since this fluorescent substance sheet formed the fluorescent substance layer by controlling a vapor deposition rate according to the temperature measurement result in the inside of the crucible 50, it is a highly accurate film | membrane formed into a film with the appropriate vapor deposition rate High quality (homogeneous) with thick fluorescence.

  As described above, the amount of activator contained in the phosphor layer is extremely small relative to the phosphor, and component control of the phosphor layer is important. According to the study by the present inventors, in order to form a high-quality phosphor layer having a thickness exceeding 200 μm in which an activator is uniformly dispersed and added (dope) in the phosphor, It is preferable to generate a mixed vapor obtained by sufficiently mixing vapors obtained by separately evaporating the film forming material and the film forming material of the activator, and perform film formation on the substrate using this mixed vapor.

Here, the details of the structural features of the crucible 52 for europium bromide (activator) with a small deposition amount will be described.
As described above, each of the crucibles 52 is provided with the coil heater 52b at a certain distance from the main body 52c of the crucible 52, and a resistance heating power source is connected to the heater. What is further required here is that the coil heater 52b is configured to have a constant pitch p as much as possible, as shown in FIG.

  The above-mentioned distance between the main body 52c of the crucible 52 and the coil heater 52b is about 0.1 mm or more and 50 mm or less, and preferably is uniform with an error of about 10% or less. Further, the uniformity of the pitch of the coil heater 52b is preferably within an error of about 10% with respect to a predetermined pitch. Similarly, the thickness of the main body 52c of the crucible 52 is preferably about 0.2 mm to 1 mm, and the thickness variation is preferably as small as possible.

  Thus, by stabilizing the distance between the main body 52c of the crucible 52 and the coil heater 52b, the pitch of the coil heater 52b, and the thickness of the main body 52c of the crucible 52, stable europium bromide (activator) ) Can be realized, thereby obtaining an effect that a high-quality (homogeneous) phosphor layer can be formed.

5A and 5B, other embodiments of the crucible 52 are listed.
FIG. 5A shows that the bottom of the main body 52c of the crucible 52 has a curved surface, and the coil heater 52b is formed so as to follow the shape of the bottom even when the bottom is curved. An example is shown. However, in this case, the distance between the bottom portion of the main body 52c of the crucible 52 and the coil heater 52b is set apart by a certain distance, and the pitch of the coil heater 52b at the bottom portion is the virtual heating surface formed by the coil heater 52b. Consider the heat generation per unit area to be uniform.

  FIG. 5 (b) shows a case where the main body 52c of the crucible 52 has an inverted truncated cone shape instead of a cylindrical shape. In this case, the gap between the main body 52c of the crucible 52 and the coil heater 52b is shown. The distance may be a constant dimension similar to that of the cylindrical shape, but the pitch of the coil heater 52b is the virtual heat generated by the coil heater 52b as in the case of FIG. Care must be taken so that the amount of heat generated per unit area of the surface is uniform.

  That is, the shape of the crucible (heating evaporator) according to the present invention is not particularly limited, and the coil heater is a heating element so as to have a certain distance from the side wall surface (substantially the outer wall surface). Or the like may be arranged so that uniform heating can be performed.

  The above embodiment shows an example of the present invention, and the present invention is not limited to the above embodiment, and various modifications and improvements are made without departing from the spirit of the present invention. Needless to say, it may be.

It is sectional drawing which shows the structure of the crucible which concerns on one Embodiment of this invention. (A) is a schematic front view of an example of the fluorescent substance sheet manufacturing apparatus which actualized the fluorescent substance sheet manufacturing method, (b) is the schematic side view. It is a schematic plan view of the heating evaporation part of the fluorescent substance sheet manufacturing apparatus shown in FIG. (A) is a top view of the crucible of the phosphor sheet manufacturing apparatus shown in FIG. 2, (b) is the same schematic front view, and (c) is a schematic side view of the same. It is sectional drawing which shows the structure of the crucible which concerns on other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 (Phosphor sheet) Manufacturing apparatus 12 Vacuum chamber 14 Substrate holding conveyance means 16 Heating evaporation part 18 Gas introduction nozzle 20 (Resistance heating) Power supply 22 Heating control means 30 Substrate holding means 32 Substrate conveyance means 34 Guide rails 36, 48 Engagement Member 40 Screw shaft 42 Nut portion 44 Rotation drive source 50, 52 Crucible 52b Coil heater 52c Crucible body 58 Thermocouple 62 Shielding member S Glass substrate p Coil heater pitch

Claims (4)

In a heating and evaporating apparatus consisting of a coil heater and a container,
The heating and evaporation apparatus characterized in that the coil portion of the coil heater and at least the side wall portion of the container are not in contact with each other, and the distance between the coil portion and the side wall portion of the container is substantially constant. .   The heating evaporation apparatus according to claim 1, wherein a material constituting the container is a refractory metal or ceramic.   3. A multi-source vapor deposition method using the heat evaporation apparatus according to claim 1 or 2 for heat evaporation of an evaporation component having the highest evaporation temperature in a multi-component vapor deposition apparatus.   3. A multi-source vapor deposition method, wherein the heat evaporation apparatus according to claim 1 or 2 is used for heat evaporation of an evaporation component having the smallest evaporation amount in a multi-component vapor deposition apparatus.

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