POWDER DEPOSITION APPARATUS AND POWDER DEPOSITION METHOD

There is provided a powder deposition apparatus including a drum-like rotating body disposed in a vacuum container and configured to rotate in a vertical direction, a deposition source disposed inside the drum-like rotating body, a tubular powder supplying/recovering member disposed close to an inner wall of the drum-like rotating body and configured to recover powder coming through an upper face and to supply the powder to the inner wall through a lower face, and a lid member provided in a vicinity of the lower face of the powder supplying/recovering member and configured to supply the powder to the inner wall through the lower face of the powder supplying/recovering member by being allowed in an open state and to accumulate the powder coming in the powder supplying/recovering member through the upper face by being allowed in a closed state.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

[1. Configuration of Powder Deposition Apparatus]

FIG. 1andFIG. 2are diagrams illustrating a configuration of a powder deposition apparatus as an example according to an embodiment of the present disclosure.FIG. 1is a lateral view thereof andFIG. 2is a perspective view thereof.

The powder deposition apparatus includes a rotating body10disposed in a vacuum container30. The vacuum container30only has to have a shape in which the rotating body10can be accommodated. The rotating body10is supposed to have a dimension, for example, of approximately 50 cm in diameter.

As illustrated inFIG. 1andFIG. 2, the rotating body10is a drum-like rotating body and includes an inner wall10awith a predetermined width. The rotating body10is not provided with a shutting member on its side face, whereas the rotating body10may be configured to shut its side face with a side face plate.

The rotating body10rotates around a rotation center axis11. A rotation rate of the rotating body10is configured to be relatively high such that powder sticks to the inner wall10adue to centrifugal force. In the figures, a driving source or a rotation mechanism performing rotation driving on the rotating body10is omitted.

Moreover, a deposition source12is disposed in an upper portion of the interior of the rotating body10. The deposition source12heats and vaporizes a material of which a coating film is to be formed. Vapor generated by the vaporization in the deposition source12reaches an upper portion of the inner wall10aof the rotating body10through an upper part12aof the deposition source12.

Moreover, a powder supplying/recovering apparatus20is disposed inside the rotating body10. The main body of the powder supplying/recovering apparatus20is configured of a tubular part21constituted of a tubular member with a rectangular cross section. An upper face22and a lower face23of the tubular part21are in an open state. Moreover, the tubular part21is configured to have a relatively large length so as to have a function of stirring powder inside it.

The powder supplying/recovering apparatus20is retractable to undergo pivotal motion around a pivot fulcrum24at its lower end as indicated by the virtual lines inFIG. 1. Namely, the powder supplying/recovering apparatus20can be configured to take one of two states of an upright state of the tubular part21and an inclined state of the tubular part21due to pivotal motion θ1 around the pivot fulcrum24.

When the powder supplying/recovering apparatus20is in the upright state of the tubular part21, an edge22aof the upper face22of the tubular part21comes into contact with the inner wall10aof the rotating body10. When the powder supplying/recovering apparatus20is in the inclined state of the tubular part21, the edge22aof the upper face22of the tubular part21separates from the inner wall10aof the rotating body10.

FIG. 3is an enlarged view illustrating a lower portion of the tubular part21of the powder supplying/recovering apparatus20. As illustrated inFIG. 3, the lower face23of the tubular part21is a slope inclined by approximately 45°. A mesh member28is disposed on the lower face23which is inclined. The mesh member28functions as a member stirring powder coming outside through the lower face23of the tubular part21. Stirring powder using the mesh member28is one example and another member may stir the powder.

Moreover, two slits26and27opposite to each other are provided in the vicinity of the lower face23of the tubular part21. A lower portion of the tubular part21is allowed in a closed state by inserting a plate-like lid member25through the two slits26and27. The lid member25is horizontally moved along an arrow M1 illustrated inFIG. 2, and thereby, can be drawn out through the slit26. A mechanism driving the lid member25is omitted in the figures.

Drawing the lid member25out through the slit26allows the tubular part21in a state where the lower portion is open and allows the powder in the tubular part21to be discharged into the rotating body10through the lower face23. In this case, the lid member25can be adjusted to be in a half-open state or the like to whose extent the lower portion of the tubular part21is open, depending on a configuration of an amount by which it is drawn out through the slit26. An amount of the powder to be discharged into the rotating body10can be adjusted depending on the extent to which the lower portion of the tubular part21is open.

In addition, the powder deposition apparatus includes a controlling apparatus installed outside the vacuum container30. The controlling apparatus controls rotation of the rotating body10, pivotal motion of the powder supplying/recovering apparatus20and opening and closing of the lid member25. These controls are performed in association with deposition by the deposition source12.

[2. Flow of Powder Deposition Operation]

Next, a flow of processing of attaching a material to the surfaces of the powder due to deposition is described with reference to a flowchart inFIG. 4andFIG. 5toFIG. 8each illustrating status in each process. InFIG. 5toFIG. 8each illustrating status in each process, the powder is designated by reference numeral31. Used powder31is composed, for example, of fine particles made of metal or the like each of which has a diameter of approximately micrometers to tens of micrometers. Moreover, as a deposition material, for example, copper is used.

First, as illustrated inFIG. 5, the powder supplying/recovering apparatus20allows the lid member25in the state where spacing between the slits26and27is shut. The powder31is put into the tubular part21of the powder supplying/recovering apparatus20thus allowed in the closed state. At this stage, the tubular part21of the powder supplying/recovering apparatus20is allowed in the inclined state such that the edge22aof the upper face22of the tubular part21is not brought into contact with the inner wall10aof the rotating body10.

Then, the operator starts operation of making the inside of the vacuum container30which is disposed in the powder supplying/recovering apparatus20into which the powder is thus put at a vacuum. The controlling apparatus may automatically perform the starting of the vacuum operation.

After reaching the degree of vacuum expected for deposition, the controlling apparatus rotates the rotating body10fast. The rotation rate at this stage is configured to be a rate to an extent to which the powder31sticks to the inner wall10aof the rotating body10due to centrifugal force. Such a rate is a rate, for example, of approximately one hundred and tens of cycles per minute. Moreover, the rotating direction is configured to be a direction in which the powder31supplied through the lower face23of the powder supplying/recovering apparatus20passes the vicinity of the deposition source12in the upper portion to reach the upper face22of the powder supplying/recovering apparatus20. InFIG. 1, such a rotating direction is a direction in which the hands of the clock rotate.

Then, in the state where the rotating body10thus rotates fast, the lid member25in the lower portion of the powder supplying/recovering apparatus20is drawn out through the slit26. The drawing-out of the lid member25starts the supply of the powder onto the inner wall10athrough the lower face23of the powder supplying/recovering apparatus20(step S11).

FIG. 6is a diagram illustrating such status. In the example illustrated inFIG. 6, the lid member25is allowed in the half-open state by adjusting the amount by which it is drawn out through the slit26. By doing so, the powder31is supplied onto the inner wall10aportion by portion. Supplying the powder31as above allows the powder31in the state where it sticks to the inner wall10aof the rotating body10rotating fast due to centrifugal force.

Then, after an amount of the powder31is supplied onto the inner wall10ato some extent, the controlling apparatus allows the powder supplying/recovering apparatus20in the upright state (step S12). When the powder supplying/recovering apparatus20is allowed in the upright state, the edge22aof the upper face22of the tubular part21comes into contact with the inner wall10aof the rotating body10. Upon this, the deposition source12starts deposition. The starting of the deposition conducts the vaporization of the deposition material (step S13).

FIG. 7is a diagram illustrating such status. As illustrated inFIG. 7, performing the deposition by the deposition source12allows the vaporized material to reach the powder31which sticks to the inner wall10aand has reached the upper portion, films, which are made of the deposition material, formed on the surfaces of the powder31.

Then, the rotation of the rotating body10allows the powder31having undergone the deposition to reach the portion of contact with the edge22aof the upper face22of the tubular part21. At this stage, the portion where the inner wall10aof the rotating body10comes into contact with the edge22ascratches the powder31off. Due to this, the powder31is recovered in the tubular part21through the upper face22of the powder supplying/recovering apparatus20.

Furthermore, as illustrated inFIG. 7, after the recovered powder31is stirred inside the tubular part21which is relatively long, it is discharged onto the inner wall10aof the rotating body10through the lower face23of the tubular part21. Also in the discharge through the lower face23, the powder31is stirred by the mesh member28.

The operation of the state illustrated inFIG. 7is continuously performed, and thus supply of the powder31, deposition to the powder31supplied, and recovery of powder31deposited are repetitively performed.

Then, a controlling part determines whether or not the deposition in the status illustrated inFIG. 7is performed for a prescribed time period or more (step S14), and the deposition in step S13is performed until the prescribed time period elapses. The prescribed time period is configured to be relatively long, for example, approximately one hour to tens of hours. Performing the deposition continuously for the time period thus prescribed enables to perform deposition of copper on the surfaces, for example, of metal particles in approximately 10 wt %.

Then, when it is determined that the prescribed time period elapses in step S14, while the deposition source12is stopping the deposition, the lid member25in the lower portion of the powder supplying/recovering apparatus20is inserted through the slit26, the lower portion allowed in the closed state (step S15). By doing so, the recovered powder31is accumulated in the tubular part21of the powder supplying/recovering apparatus20.

FIG. 8is a diagram illustrating such status. As illustrating inFIG. 8, the powder31is being scratched off and the recovered powder31is being accumulated inside the tubular part21of the powder supplying/recovering apparatus20.

Then, after a time period to an extent to which the powder31is accumulated elapses, the rotation of the rotating body10is stopped (step S16). After that, after the degree of vacuum in the vacuum container30is lowered, the vacuum container30is opened and the powder31accumulated in the powder supplying/recovering apparatus20is taken out.

Performing the deposition as above enables operation of attaching a deposition material to the surfaces of the powder31to be performed simply and exceedingly efficiently. For example, when the powder deposition apparatus illustrated inFIG. 1was fabricated and copper was deposited on metal particles, the powder supplying/recovering apparatus20was able to recover 90% or more of the metal particles after the end of the deposition. Moreover, such a high recovery rate of the powder leads to effects of preventing the powder from scattering in operation and preventing contamination of the deposition source.

Furthermore, the powder supplying/recovering apparatus20disposed in the rotating body10has a relatively simple configuration, and thus, the configuration of the powder deposition apparatus can be made simple.

In addition, in the above-mentioned embodiment, when the powder supplying/recovering apparatus20recovers the powder, the edge22aof the upper face22of the powder supplying/recovering apparatus20is configured to come into contact with the inner wall10aof the rotating body10. In place of such a contact state, the edge22aof the upper face22of the powder supplying/recovering apparatus20may be in a state where the inner wall10aof the rotating body10is close to it by a subtle gap given toward it and the powder supplying/recovering apparatus20may recover the powder from the inner wall10aof the rotating body10.

Moreover, in the above-mentioned embodiment, the mesh member28as a diffusion member is disposed on the lower face23of the powder supplying/recovering apparatus20. On the contrary, a diffusion member with another shape may be disposed on the lower face23to diffuse the powder. Moreover, in place of the mesh member28thus disposed, when the lid member25is drawn out through the slit26, a punching metal plate in which many fine openings are disposed may be inserted through the slit26and the punching metal plate may diffuse the powder.

Moreover, in the above-mentioned embodiment, the plate-like lid member25is used as a member opening and closing the lower portion of the powder supplying/recovering apparatus20. On the contrary, another configuration may open and close the lower portion. Moreover, an opening amount in opening and closing with the lid member25or the like may be adjusted depending on the amount, diameter or the like of the powder used.

Moreover, in the above-mentioned embodiment, the inside of the tubular part21of the powder supplying/recovering apparatus20is configured to be a relatively long cavity, the powder stirred when the powder passes through the cavity. On the contrary, a member stirring the powder may be disposed inside the tubular part21, positively performing the stirring.

Moreover, in the example of the above-mentioned embodiment, the example of depositing copper on the surfaces of metal particles is described, whereas a material of particles or a deposition material is one example and any combination of those may be employed as long as the material can be deposited.

(1) A powder deposition apparatus including:

a drum-like rotating body disposed in a vacuum container and configured to rotate in a vertical direction;

a deposition source disposed inside the drum-like rotating body;

a tubular powder supplying/recovering member disposed close to an inner wall of the drum-like rotating body and configured to recover powder coming through an upper face and to supply the powder to the inner wall through a lower face; and

a lid member provided in a vicinity of the lower face of the powder supplying/recovering member and configured to supply the powder to the inner wall through the lower face of the powder supplying/recovering member by being allowed in an open state and to accumulate the powder coming in the powder supplying/recovering member through the upper face by being allowed in a closed state.

(2) The powder deposition apparatus according to (1),

wherein the lid member supplies the powder to the inner wall under gradual change from the closed state to the open state in a state where the drum-like rotating body rotates at a rate to an extent to which centrifugal force generates such that the powder does not fall off the inner wall.

(3) The powder deposition apparatus according to (1) or (2),

wherein the powder supplying/recovering member is movable between a state where the upper face separates from the inner wall of the drum-like rotating body and a state where the upper face comes into contact with or is close to the inner wall of the drum-like rotating body,

wherein the upper face is allowed in the state where the upper face separates from the inner wall of the drum-like rotating body when the powder is supplied to the inner wall under gradual change from the closed state to the open state of the lid member, and

wherein the upper face is allowed in the state where the upper face comes into contact with or is close to the inner wall of the drum-like rotating body when the powder is recovered from the inner wall.

wherein, after supplying the powder to the inner wall of the drum-like rotating body through the lower face of the powder supplying/recovering member in the open state of the lid member while the powder supplying/recovering member recovers the powder from the inner wall of the drum-like rotating body, and the upper face is allowed in the state where the upper face comes into contact with or is close to the inner wall of the drum-like rotating body, the powder is accumulated in the powder supplying/recovering member, and the lid member is allowed in the closed state.

(5) The powder deposition apparatus according to any one of (1) to (4),

wherein a member configured to stir the powder is disposed on the lower face of the powder supplying/recovering member.

(6) A powder deposition method including:

disposing, in a vacuum container, a drum-like rotating body configured to rotate in a vertical direction;

disposing a deposition source inside the drum-like rotating body;

performing deposition by the deposition source after powder is supplied to an inner wall of the drum-like rotating body in a state where the drum-like rotating body rotates and a bottom portion of a tubular powder supplying/recovering member allowed in an open state;

recovering the powder supplied to the inner wall of the drum-like rotating body through an upper face of the tubular powder supplying/recovering member; and

accumulating the recovered powder in the tubular powder supplying/recovering member by allowing a vicinity of a lower face of the tubular powder supplying/recovering member in a closed state.