Abstract:
This invention relates to a manufacturing method and manufacturing apparatus of thin film article by cutting a thin film sheet conveyed as being mounted on a conveying medium of thin film shape into a special size to obtain a thin film sheet piece, and conveying and laminating said thin film sheet piece at a laminating position by a ball-screw mechanism, wherein the cutting position of said thin film sheet is determined on the basis of an image taken by imaging means moving in synchronism with conveyance of said thin film sheet piece.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to a manufacturing method and a manufacturing apparatus of a thin film laminated article. More particularly, it relates to a manufacturing method and a manufacturing apparatus of a thin film laminated article for manufacturing laminated ceramic capacitor or the like by cutting, for example, a ceramic sheet on which an electrode pattern is formed into a sheet piece of a specified size, and laminating. 
     BACKGROUND ART 
     Hitherto, in a manufacturing apparatus for manufacturing electronic components such as laminated ceramic capacitors, a CCD imaging device is used for positioning in the case of printing an electrode pattern on a ceramic sheet formed on a flexible support called a carrier film, or cutting the ceramic sheet on which the electrode pattern is printed into a sheet piece of a specified size (refer to Japanese Laid-open Patent Publication No. 8-167544 and Japanese Laid-open Patent Publication No. 10-284346). 
     FIG. 5 shows a schematic structure of the thin film laminated article manufacturing apparatus of the prior art for positioning by using a CCD imaging device when cutting the ceramic sheet on which the electrode pattern is printed into a sheet piece of a specified size. 
     This manufacturing apparatus  100  comprises a film conveying mechanism  101  for conveying a carrier film F on the surface of which ceramic sheet G is formed, a cutting and conveying mechanism  102  for cutting the ceramic sheet G on the surface of the carrier film F conveyed by this conveying mechanism  101  into a sheet piece of a specified size, and conveying to a specified position, a positioning mechanism  103  for positioning when the cutting and conveying mechanism  102  cuts off the ceramic sheet G, and a laminating and compressing mechanism  104  for laminating and compressing the ceramic sheet conveyed to the specified position by the cutting and conveying mechanism  102 . 
     The film conveying mechanism  101  has a delivery device  105  in which the carrier film F having the ceramic sheet G formed on the surface is set, and the carrier film F delivered from this delivery device  105  is conveyed to a take-up device  107  while being guided by rolls  106 , and is taken up. 
     The cutting and conveying mechanism  102  includes a conveying unit  110  having a cutting blade  108  for cutting the ceramic sheet G into a sheet piece of a specified size on a peeling table  115  used as a support stand, and a suction board  109  for sucking the ceramic sheet G, a rod-less fluid cylinder  111  for moving the conveying unit  110  between a cut-off position for cutting off the ceramic sheet G by the conveying unit  110  and a laminating position for laminating and compressing the sheet piece by the laminating and compressing mechanism  104 , and a ball-screw mechanism  112  for moving this rod-less fluid cylinder  111  by a short distance for fine adjustment. 
     The positioning mechanism  103  includes a CCD imaging device  113   a  for imaging the positioning mark printed at a specified interval corresponding to the electrode pattern on the ceramic sheet G, and an image processing device  113   b  for processing the image taken by the CCD imaging device  113   a , and by the correction moving distance obtained by processing the image information of the positioning mark taken by this CCD imaging device  113   a  by the image processing device  113   b , it is designed to determine positioning when moving the conveying unit  110  from the laminating position to the cut-off position. 
     The laminating and compressing mechanism  104  is composed of a press table  114  for laminating and compressing the ceramic sheet conveyed up to the laminating position by the cutting and conveying mechanism  102 , and a hydraulic cylinder  150  for pushing up this press table  114 . 
     In this prior art, the conveying unit  110  is moved by an almost full distance by the rod-less fluid cylinder  111 , and the conveying unit  110  is positioned so that the ball-screw mechanism  112  may move the cylinder  111  by a short distance. It hence prevents deviation of position of the sheet piece being laminated and compressed due to thermal expansion in the axial direction of the ball-screw shaft  112   a  by friction heat, for example, when moving the conveying unit  110  the full distance by using the ball-screw mechanism  112 . 
     Referring next to FIG.  6  and FIG. 7, in the case of moving the full distance by using the ball-screw mechanism  112 , deviation of position of sheet piece being laminated and compressed due to thermal expansion in the axial direction of the ball-screw shaft  112   a  due to friction heat is explained below. FIG. 6 shows a starting state of the manufacturing apparatus  100 , and FIG. 7 shows a laminating state of a specified number of sheet pieces. 
     In FIG.  6  and FIG. 7, point A shows the bearing position at the leading end of the ball-screw shaft  112   a  of the ball-screw mechanism  112 . Point B 1  denotes the reference position of the conveying unit  110  stopped at the laminating position, that is, the center of the press table  114 , and the distance from point A to point B 1  is L 1 . Point B 2  shows the position of the conveying unit  110  stopped at the laminating position actually at the point shown in FIG.  7 . That is, in the state in FIG. 6, the position of the conveying unit  110  coincides with the center of the press table  114 , but in the state in FIG. 7, the stopping position at the laminating position of the conveying unit  110  is point B 2 , being deviated from point B 1  by ΔL 1  in the leftward direction in the drawing due to the effect of thermal expansion. 
     Point C 1  is a fixing position of the CCD imaging device  113   a , and is also a reference position at the cut-off position of the positioning mark printed on the ceramic sheet G. Point C 1  is a point moved from point B 1  by L 2  in the leftward direction in the drawing. 
     Point D 1  shows a position when the conveying unit  110  is moved to the cut-off position, assuming that the deviation detected by the CCD imaging device  113   a  to be 0. Point D 1  coincides with point C 1 , and actually distance L 2  is corrected depending on the deviation of positioning mark from point C 1 , and the moving distance when the conveying unit  110  is moved from point B 1  to the cut-off position. 
     Point D 2  shows a position in which the conveying unit  110  is stopped at the cut-off position, assuming that the deviation detected by the CCD imaging device  113   a  to be 0 at the point shown in FIG.  7 . The distance from point D 2  to point B 2  is L 2 +ΔL 2  due to the effect of thermal expansion of the ball-screw shaft  112   a . Therefore, in the state shown in FIG. 7, the conveying unit  110  is stopped at a position deviated from point D 1  by ΔL 1 +ΔL 2  in the leftward direction in the drawing. 
     As a result, at the point in FIG. 7, the sheet piece laminated at the laminating position is deviated from the initial position by ΔL 1  in the leftward direction in the drawing, and the position of the positioning mark (that is, the position of the electrode pattern; in FIG. 7, line segment E shows the position of the positioning mark) is deviated by ΔL 2  in the rightward direction in the drawing. 
     Thus, when moving the conveying unit  110  between the cut-off position and laminating position by the ball screw mechanism  112 , since the ball screw shaft  112   a  is elongated by thermal expansion from start until the temperature of the ball-screw shaft  112   a  is stabilized, the electrode pattern of the laminated sheet pieces is deviated. In this respect, in the prior art, since the conveying unit  110  is moved in the majority between the cut-off position and laminating position by the rod-less fluid cylinder  111 , deviation of electrode pattern due to effect of thermal expansion of the ball-screw shaft  112   a  may be suppressed to an ignorable level. 
     In the prior art, however, the manufacturing apparatus requires a relatively complicated mechanism of the rod-less fluid cylinder  111 , and hence the mechanism of the manufacturing apparatus is complicated, and the manufacturing cost of the thin film laminated body is increased. 
     The invention is devised in the light of the problems of the prior art, and it is hence an object thereof to present a manufacturing method and a manufacturing apparatus of a thin film laminated article capable of eliminating adverse effects on the product precision by thermal expansion of members without complicating the mechanism. 
     SUMMARY OF THE INVENTION 
     The manufacturing method of thin layer laminated article of the invention is characterized by cutting a thin film sheet conveyed as being mounted on a conveying medium of thin film shape into a specified size to obtain a thin film sheet piece, and conveying and laminating the thin film sheet piece at a laminating position by a ball-screw mechanism, in which the cutting position of the thin film sheet is determined on the basis of the image taken by imaging means moving in synchronism with conveyance of the thin film sheet piece. 
     Preferably, in the manufacturing method of thin layer laminated article of the invention, the center of the laminating position is the middle position between the center of the cutting position and the bearing position of the ball-screw shaft leading end of the ball-screw mechanism. 
     On the other hand, the manufacturing apparatus of thin layer laminated article of the invention comprises a conveying medium conveying mechanism for conveying a conveying medium of thin film shape on which a thin film sheet is mounted, cutting means for cutting the thin film sheet into a thin film sheet piece of a specified size, holding and conveying means for holding the thin film sheet piece and conveying from a cutting position to a laminating position, a ball-screw mechanism for conveying the holding and conveying means from the cutting position to laminating position, imaging means designed to move in synchronism with the move of the holding and conveying means, and image processing means for processing the image from the imaging means, in which the moving distance of the holding and conveying means is corrected depending on a correction moving distance from the image processing means. 
     Preferably, in the manufacturing apparatus of thin layer laminated article of the invention, the center of the laminating position is the middle position between the center of the cutting position and the bearing position of the ball-screw shaft leading end of the ball-screw mechanism. 
     Preferably, in the manufacturing apparatus of thin layer laminated article of the invention, the cutting means includes a first cutting mechanism for cutting the thin film sheet in the conveying direction and a second cutting mechanism for cutting in a direction orthogonal to the conveying direction, and the second cutting mechanism is disposed on the holding and conveying means. 
     Since the invention is thus constituted, if the holding and conveying means is conveyed to a position deviated from a preset cut-off position due to thermal expansion of the ball-screw shaft of the ball-screw mechanism, the holding and conveying means can be set at the specified position by the correction moving distance obtained by processing the image taken by the imaging means. It hence eliminates adverse effects of thermal expansion of ball-screw shaft on the product precision. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view showing a schematic constitution of a manufacturing apparatus of thin film laminated article according to an embodiment of the invention. 
     FIG. 2 is a plan view showing a schematic constitution of the manufacturing apparatus of thin film laminated article according to the embodiment of the invention. 
     FIG. 3 is an explanatory illustration of operating principle of the manufacturing apparatus of thin film laminated article according to the embodiment of the invention, showing a starting state. 
     FIG. 4 is an explanatory illustration of operating principle of the manufacturing apparatus of electronic component according to the embodiment of the invention, showing a state after a specified time. 
     FIG. 5 is a front view showing a schematic constitution of a conventional manufacturing apparatus of thin film laminated article. 
     FIG. 6 is a illustration explaining problems of the conventional manufacturing apparatus of thin film laminated article, corresponding to FIG.  3 . 
     FIG. 7 is an illustration explaining problems of the conventional manufacturing apparatus of electronic component, corresponding to FIG.  4 . 
    
    
     DETAILED DESCRIPTION 
     Referring now to the accompanying drawings, an embodiment of the invention is described below, but it must be noted that the invention is not limited to the illustrated embodiment alone. 
     FIG.  1  and FIG. 2 show a schematic structure of a manufacturing apparatus in which a manufacturing method of a thin film laminated body in an embodiment of the invention is applied. 
     This manufacturing apparatus  1  comprises primarily a film conveying mechanism  2  for conveying so that a carrier film F on the surface of which a ceramic sheet G is formed may be fed by a specified length each, a cutting mechanism C for cutting the ceramic sheet G on the surface of the carrier film F conveyed by this conveying mechanism  2  into a sheet of a specified size, a sheet conveying mechanism  3  for conveying this sheet piece to a specified position, a positioning mechanism  4  for positioning when the cutting mechanism C cuts off the ceramic sheet G, and laminating and compressing mechanism  5  for laminating and compressing the ceramic sheet G conveyed up to the specified position by the sheet conveying mechanism  3 . 
     Herein, the carrier film F is composed of a hard resin material such as biaxially drawn polyethylene terephthalate film (polyester film) or biaxially drawn polypropylene film. 
     On the other hand, the ceramic sheet G is a slurry composition composed of various ceramic dielectric power materials, resin binders and solvents formed on the surface of the carrier film F by coating method or printing method. The thickness of this ceramic sheet G is about, for example, 2 to 30 μm. 
     On the upper surface of the ceramic sheet G, a conductive material containing palladium, silver, nickel or other metal powder is printed as a rectangular electrode pattern, and the positioning mark is printed at a specified interval corresponding to the electrode pattern for the purpose of positioning when cutting off the ceramic sheet G. 
     The film conveying mechanism  2  has a delivery device  6  in which the carrier film F having the ceramic sheet G formed on the surface is set, and the carrier film F delivered from this delivery device  6  is conveyed up to a take-up device  8  while being guided by a group of rolls  7 , and is taken up. 
     Of the group of rolls  7 , a suction roll  9  has a vacuum outer circumference, and rotates while sucking the carrier film F, and conveys the carrier film F. Above the suction roll  9 , there is a longitudinal cutter  10  composing the cutting mechanism C for cutting only the ceramic sheet G longitudinally in the running direction on the suction roll  9  as a support stand. The longitudinal cutter  10  is constituted so that a rotary blade support member  10   c  for supporting, for example, two circular rotary blades  10   a ,  10   b  may be thrust toward the suction roll  9  with a proper force by a thrusting member  10   d.    
     The carrier film F sent by rotation of the suction roll  9  is provided with a proper tension by a supply side tension roll  11 , a take-up side tension roll  12 , and a moving roll  13 , and conveyed to the take-up device  8  while being guided by guide rollers  14   a ,  14   b ,  14   c ,  14   d ,  14   e ,  14   f.    
     The sheet conveying mechanism  3  includes a conveying unit  15  for cutting the ceramic sheet G in a direction orthogonal to the running direction, which the ceramic sheet G has been cut prior in the running direction by a longitudinal cutter  10  before reaching the conveying unit  15  and form into a sheet piece of a specified size, and sucking and holding this sheet piece, and a ball-screw mechanism  16  for moving this conveying unit  15  between the cut-off position for cutting off the ceramic sheet G, and the laminating position for compressing and laminating the cut-off ceramic sheet G by the laminating and compressing mechanism  5 . 
     The conveying unit  15  includes a lateral cutter  15   a  for cutting the ceramic sheet G in a direction orthogonal to the running direction on a peeling table  33  as a support stand to form into a sheet piece of a specified size, and a suction board  15   b  for sucking and holding the sheet piece. The ball-screw mechanism  16  comprises a ball-screw shaft  17  having one end (leading end) supported on a base  1   a  of the manufacturing apparatus  1 , a servo motor  19  for rotating and driving the ball-screw shaft  17  having other end (rear end) of the ball-screw shaft  17  connected through a shaft coupling  18 , and a ball female screw  20  fixed in the conveying unit  15  to be engaged with the ball-screw shaft  17 . As clear from the description above, in the embodiment, the cutting mechanism C is composed of the longitudinal cutter, that is, the first cutting mechanism, and the lateral cutter, that is, the second cutting mechanism. 
     The shaft coupling  18  is designed to absorb the elongation so as not to break the machine when the ball-screw shaft  17  is elongated in the axial direction due to thermal expansion. A specific constitution is known in the prior arts. 
     The positioning mechanism  4  includes a CCD imaging device  21 A for imaging the positioning mark printed at a specified interval corresponding to the electrode pattern on the ceramic sheet G, and an image processing device  21 B for processing the image taken by this CCD imaging device  21 A, and depending on the correction amount obtained by processing the image information of the positioning mark taken by the CCD imaging device  21 A by the image processing device  21 B, it is designed to correct the distance when the ball-screw mechanism  16  moves the conveying unit  15  from the laminating position to the cut-off position. 
     The CCD imaging device  21 A is engaged with the ball female screw  20  through a support metal  21   a , that is, coupled to the conveying unit  15  through the ball female screw  20 , and it is designed to move integrally with the conveying unit  15 . 
     The laminating and compressing mechanism  5  includes a press table  24  for supporting a carrier plate  23  supplied from a carrier plate feed device  22  and conveyed by a carrier plate conveyor  31 , and a hydraulic cylinder  25  supported on a base stand la for moving up and down this press table  24 , and this hydraulic cylinder  25  temporarily compresses and laminates the sheet piece, and the temporarily compressed sheet piece is pressed by a final compression press  26  as required. 
     On the top of the carrier plate  23 , a low-viscosity or heat-peeling glue is applied, and the sheet piece is adhered thereto, and the sheet piece can be peeled off without damaging when removing the laminated sheet piece from the carrier plate  23 . Instead of applying the glue directly on the carrier plate  23 , for example, a double-side adhesive sheet coated with low-viscosity or heat-peeling glue may be adhered to the carrier plate  23 , and the sheet piece may be laminated and compressed thereon. 
     In this case, in the midst of laminating a specified number of sheet pieces, when laminating other sheet such as a dummy sheet on which electrode pattern is not printed, the carrier plate  23  is discharged from the press table  24 , and the sheet prepared by the blank sheet feed device  27  may be put on the laminated body on the carrier plate  23 . 
     The carrier plate  23  pressed by the final compression press  26  before the specified number of sheets are laminated is returned to the press table  24  by the carrier plate conveyors  28 ,  29 ,  30 , whereas the carrier plate  23  laminating the specified number of sheet pieces is pressed, as required, by the final compression press  26 , and put into a carrier plate storage device  32 . 
     Referring next to FIG.  3  and FIG. 4, the principle of positioning the conveying unit  15  by the positioning mechanism  4  is explained below. 
     FIG. 3 shows a starting state of the manufacturing apparatus  1 . FIG. 4 shows a state after a specific number of sheet pieces are laminated. 
     In FIG.  3  and FIG. 4, point A denotes the bearing position of the ball-screw shaft  17 . Point B 1  indicates a reference position where the conveying unit  15  is stopped at the laminating position, that is, the center of the press table  24 , and the distance from point A to point B 1  is L 1 . 
     Point B 2  shows the position of the conveying unit  15  actually stopped at the laminating position at the point in FIG.  4 . That is, in the state in FIG. 3, the position of the conveying unit  15  coincides with the center of the press table  24 , but in the state in FIG. 4, the stopping position at the laminating position of the conveying unit  15  is point B 2  deviated from point B 1  by ΔL 1  in the leftward direction in the drawing due to effect of thermal expansion. 
     Point C 1  shows the position of the CCD imaging device  21 A when the conveying unit  15  is at point B 1  upon start of the manufacturing apparatus  1 . This position is also the reference position at cut-off position of the positioning mark printed on the ceramic sheet G. Point C 1  is a point moving from point B 1  by L 2  in the leftward direction in the drawing. 
     Point C 2  is the position of the CCD imaging device  21 A at the point in FIG.  4 . The CCD imaging device  21 A is coupled to the conveying unit  15  through the ball female screw  20  by means of support fitting  21   a , and this support fitting  21   a  is free from effect of friction heat and does not elongate due to thermal expansion, and therefore the distance between point C 2  and point B 2  may be regarded to be L 2 . 
     Herein, supposing the number of pulses of the servo motor  19  for moving the conveying unit  15  by distance L 2  when starting up the manufacturing apparatus  1  to be NL 2 , at the point in FIG. 4, by this number of pulses NL 2 , the conveying unit  15  is moved by a distance (L 2 +ΔL 2 ). Therefore, to move the conveying unit  15  at point B 2  by distance L 2  in the leftward direction in the drawing, the moving unit  15  moves a distance of L 2 +ΔL 2 , moving from point A to point D 2  at L 1 +L 2 +(ΔL 1 +ΔL 2 ) in the leftward direction in the drawing. 
     At the point in FIG. 4, however, since the CCD imaging device  21 A is at point C 2  deviated from the original reference position of point C 1  by ΔL 1  in the leftward direction in the drawing, correcting the moving distance L 2  of the conveying unit  15  depending on the image information of the positioning mark developed by this CCD imaging device  21 A, −ΔL 1  is added to the original correction amount, and the moving distance L 2  is corrected. Therefore, assuming the deviation of the positioning mark from point C 1  to be 0, the conveying unit  15  moves a distance of (L 2 +ΔL 2 )−ΔL 1  from point B 2  when moving to the cut-off position. 
     The reference position of the positioning mark at this time is at a position of a distance of (L 2 −ΔL 1 ) from point B 2  in the leftward direction in the drawing, and therefore the position of the positioning mark on the ceramic sheet G held by the conveying unit  15  is a position of (L 2 −ΔL 1 ) from the center of the conveying unit  15 , that is, a position deviated by L 2  in the rightward direction. 
     When returning to the laminating position in this state, the position of the conveying unit  15  is point B 2 , that is, a position at a distance of (L 1 +ΔL 1 ) in the leftward direction in the drawing from point A, and therefore the position of the positioning reference mark at this time is a position of a distance of (L 1 +ΔL 1 −ΔL 2 ) in the leftward direction in the drawing from point A. 
     By adjusting the configuration of members so that ΔL 1  and ΔL 2  may be similar values, it is possible to adjust so that positioning marks may be aligned in the vertical direction as indicated by line segment H in the drawing, that is, to prevent deviation of electrode patterns of sheet pieces to be laminated. 
     According to experiments by the present applicant, when the temperature is 20 degree C, for about 25 minutes from start of the manufacturing apparatus  1 , the temperature of the ball-screw shaft  17  rises, and in the prior art, ΔL 1  was about 60 μm, and the deviation of electrode patterns of laminated sheet pieces was similar at maximum, and in the manufacturing apparatus  1  of the embodiment, by nearly equalizing the distance L 1  and distance L 2 , the deviation of electrode patterns was controlled to 0. 
     Thus, in the embodiment, the CCD imaging device  21 A for imaging the positioning mark printed corresponding to the electrode pattern on the ceramic sheet is coupled to the conveying unit  15 , and is designed to move together with this conveying unit  15 , it is effective to prevent deviation of electrode patterns of laminated sheet pieces due to change of position of the conveying unit  15  by thermal expansion of the ball-screw shaft  17  by friction heat. 
     Examples of thin film laminated articles manufactured by the manufacturing apparatus  1  of the embodiment include laminated ceramic capacitor, laminated ceramic varistor, laminated ceramic resistor, laminated piezoelectric actuator, piezoelectric transformer, laminated ceramic substrate, and other laminated ceramic products, and it must be noted that the manufacturing method of thin film laminated articles of the invention is also applicable to manufacture of other materials than ceramics. 
     According to the invention as described herein, if the holding and conveying means is conveyed to a position deviated from a preset cut-off position due to thermal expansion of ball-screw shaft of the ball-screw mechanism, by the correction moving distance obtained by processing the image taken by the imaging device, the holding and conveying means can be positioned at a specified position. It hence provides an excellent effect of elimination of adverse effects of thermal expansion of ball-screw shaft on the product precision.