Abstract:
A film laminating apparatus attaches films to electronic circuit boards, such as printed circuit boards and silicone boards or wafers. The film laminating apparatus conveys a plurality of boards at intervals, forms pieces of lamination film at the intervals of the boards on a base film with a processing area between boards and continuously conveys the base film into a reduced-pressure chamber having a board loading port, a film loading port, a laminating mechanism for attaching the lamination film on the base film to the boards, and a board unloading port for ejecting the laminated boards. Shutters are provided for opening and closing shutter sections provided in the board loading port and the board unloading port of the reduced-pressure chamber, and a vacuum source is provided for evacuating the reduced-pressure chamber when the reduced-pressure chamber is closed by the shutters. A shutter section is equipped with a shutter in the film loading port of the reduced-pressure chamber, and a detector is provided for detecting when a processing area in the film between boards being fed into the reduced-pressure chamber is in the shutter section of the film loading port. A control means then operates the shutter means of the film loading port, the board loading port, and the board unloading port to close the reduced-pressure chamber according to the result of detection by the detecting means, and actuates the vacuum source to evacuate the reduced-pressure chamber to a desired degree of vacuum. Then, the laminating means is actuated.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an apparatus which attaches films to the surfaces of sheet materials (hereinafter simply called boards), such as printed circuit boards, electronic circuit boards, and silicone wafers; and, more particularly, the invention relates to a vacuum film laminating apparatus which continuously supplies films and boards into a reduced-pressure chamber and attaches films to each board in the chamber. 
     A conventional reduced-pressure film laminating apparatus, such as disclosed in Japanese Examined Patent Publication No. 53-31670 (1978), places the whole film laminating apparatus containing a roll of film (hereinafter referred to as a film roll) in a reduced-pressure chamber, and provides a board loading opening and a board unloading opening in the walls of the reduced-pressure chamber. Each opening has a pair of pressure rolls made of, for example, elastic materials which isolate the inside of the reduced-pressure chamber from the outside, making it possible for the boards to be introduced into and removed from the chamber. This reduces fluctuations in the degree of vacuum of the reduced-pressure chamber when boards are transferred into and out from the chamber and assures the efficiency of attaching films to boards at a reduced pressure. 
     Since this conventional vacuum film-laminating apparatus disposes a film roll in the reduced pressure chamber, the chamber cannot be made smaller. Further, when a new film roll is loaded in the reduced-pressure chamber, it takes a long time to reduce the chamber pressure down to a preset degree of vacuum. Furthermore, keeping a film roll for a long period of time under a vacuum condition may cause its quality to vary. 
     When boards are loaded into the reduced-pressure chamber, the pressure-rolls may frictionally cause dust to be deposited on the surfaces of the boards. The dust on the board surfaces may make film adhesion incomplete in the film lamination process and may damage board surfaces when they are compressed to be unloaded. 
     When the pressure rolls are worn out due to friction between the rolls and the boards, the hermetic sealing of the chamber is broken and the chamber cannot maintain a preset reduced pressure. This requires frequent replacement of pressure rolls; and, consequently, this makes it difficult for the conventional vacuum laminating apparatus to respond to the demands imposed on a high vacuum device. 
     Japanese Examined Patent Publication No. 53-31670 (1978) also discloses an embodiment in which the film roll is disposed outside the reduced-pressure chamber. This embodiment is necessarily equipped with means to feed film sheets into the reduced-pressure chamber, in addition to the provision of said board loading and unloading openings. This film feeding unit has a pair of pressure rolls made of elastic material to feed film sheets there through. However, this embodiment cannot avoid the problems which may be caused by friction between the boards and the pressure rolls. 
     SUMMARY OF THE INVENTION 
     The main purpose of the present invention is to provide a reduced-pressure film-laminating apparatus which can form a clean reduced-pressure chamber having a desired degree of vacuum in a short time and continuously attach films to each board in the reduced-pressure chamber. 
     Another object of the present invention is to provide a reduced-pressure film-laminating apparatus which continuously supplies boards and films into the reduced-pressure chamber and attaches films to the boards in the chamber without damaging them. 
     To realize the aforesaid objects, the reduced-pressure film-laminating apparatus in accordance with the present invention comprises: 
     board transfer means for transferring a plurality of boards at preset intervals; 
     film transfer means for forming film sheets on a base film at the same intervals as the boards are transferred by said board transfer means, wherein these intervals on the base film are treated as processing areas between boards; 
     a reduced-pressure chamber having a board loading port, a film loading port, laminating means for attaching films to each board on said base film in said chamber, and a board unloading port which ejects the laminated boards; 
     first shutter means providing a shutter for each of said board loading and unloading ports of the reduced-pressure chamber to open and close the port; 
     vacuum means for evacuating the reduced-pressure chamber when said respective shutter means close; 
     second shutter means providing a shutter for said film loading port on said reduced-pressure chamber; 
     detecting means for detecting the extent of a processing area between boards on the base film to the shutter section of said film loading port; and 
     control means for operating said second shutter means of said film loading port, said board loading port, and said board unloading port according to the result of detection by said detecting means, thereby to close the shutters, for evacuating the reduced-pressure chamber to a preset degree of vacuum, and for turning on the laminating means. 
     In accordance with the present invention, the reduced-pressure film-laminating apparatus can supply films into the reduced-pressure chamber without contaminating the film sheets, and it can evacuate the reduced-pressure chamber to a desired degree of vacuum and attach films to clean boards. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic sectional view of a vacuum film-laminating apparatus which represents a first embodiment of the present invention. 
     FIG. 2 is a magnified sectional view of the reduced-pressure section of said vacuum film laminating apparatus of FIG.  1 . 
     FIG. 3 is a schematic sectional view of a vacuum film-laminating apparatus which represents a second embodiment of the present invention. 
     FIG. 4 is a magnified sectional view of the film loading port and its vicinity in the second embodiment illustrated in FIG.  3 . 
     FIG. 5 is a sectional view taken on the line A—A of FIG.  4 . 
     FIG. 6 is a fragmentary sectional view of the second embodiment illustrated in FIG. 3 showing an example of how the cover film of the laminate a board is cut out outside the reduced-pressure chamber. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A reduced-pressure film laminating apparatus which represents a first embodiment of the present invention will be explained with reference to FIG.  1  and FIG.  2 . 
     FIG. 1 is a schematic sectional view of the vacuum film-laminating apparatus of the present invention. The vacuum film-laminating apparatus mainly comprises a film loading section, a reduced-pressure section, a board loading section, and film-laminating and board-ejecting section. FIG. 2 is a magnified view of the reduced-pressure section which is evacuated. 
     Referring to FIG. 1, the configuration of the film loading port will be explained. Although this embodiment is designed to attach film sheets (of a film roll) to both surfaces of each board  5   a  through  5   e  (where postfixes “a” to “e” are omitted when boards are generically termed), the attaching of film to the top board surfaces only will be explained below because the top and bottom surfaces of each board are treated in the same manner (vertically symmetrical to the transfer surface of the boards). 
     As shown in FIG. 1, the dry film roll  1  consists of a continuous sheet formed of a base film  2 , resist films  3  formed on the base film  2 , and a cover film  4  which covers the resist films  3  on the base film  2 . These films are wound with the base film  2  facing outside on the roll  1 . Only the cover film  4  of the dry film roll  1  is taken up by the cover film take-up section  1   a . Since a resist film is attached to the surface of each board with a 3-mm margin around the resist film, the dry film roll  1  must have a preset width in the transverse direction of the board  5 , and, further, the resist  3  must be placed a few millimeters inward from the front end (edge) and the rear end (edge) of each board (in the direction of movement of the board). 
     For this purpose, the base film  2  is reeled out towards a cradle  6  and into contact with the cradle and is perforated together with the resist film  3  and the cover film  4  by a film perforating means which is disposed above the cradle. In this case, it is possible to perforate only the base film  2 , while cutting out both the resist film  3  and the cover film  4 . The embodiment shown in FIG.  1  and FIG. 2 has two or more film perforating means at preset intervals. For example, the embodiment uses a perforator  7  which gives two lines of perforation at a time. This perforator can be a roulette-of the type used for sewing. The cover-film take-up section  1   a  continuously takes up the cover film which is separated from the resist film by the separating roller  8 . The interval between two perforation lines made at one time by the perforator  7  is determined according to the preset intervals between boards as they are transferred. The interval between two perforation lines made on the films at one time by the perforator  7  is designated as a processing area between boards. When the perforated resist  3  on the base film comes in place on the cradle  9 , the base film  2  is vacuum-held by the cradle  9  and the resist equivalent to the processing area between boards is picked up and removed from the base film, for example, by an adhesive means. 
     The non-resist area on the base film  2  from which the resist has been removed is termed a “processing area  10 ” to distinguish it from the resist area on the base film having resist  3  (film itself) to be attached to a board  5 . The other form of the processing area  10  between boards will be explained later. 
     The configurations of the board loading section and the reduced-pressure section will be explained next. 
     As shown in FIG. 1, the chamber  11  in the reduced-pressure section comprises a stationary part  11   a  which is fixed relative to the board transfer surface, movable parts  11   b  and  11   c  which are oppositely disposed and can be moved towards the board transfer surface by means of cylinders  12   a  and  12   b , and a movable part  11   d  which can move with the moving of the movable part  11   b.    
     Vacuum seals  13  are provided on surfaces on which the movable parts  11   d  and  11   c  touch the stationary part  11   a  and surfaces on which the movable parts  11   d  and  11   b  touch each other. In other words, the stationary part  11   a  and movable parts  11   b ,  11   c , and  11   d  are fragmentary sections of the reduced-pressure chamber which are cut in parallel with the board transfer surface, and the vacuum seals are applied to the cut-out surfaces of the sections. When the movable parts move away from the stationary part  11   a , the spaces between the parts respectively form a board loading part (port), a board unloading part (port), a film loading part (port), and a film unloading part (port). When the movable parts close and touch the stationary part, a hermetic chamber  11  is formed. The movable part  11   b  is a lid-shaped part. The movable part  11   d  and the stationary part  11   a  are cylindrical parts, and the movable part  11   c  is pan-shaped. Their contact surfaces are provided with vacuum seals  13 . 
     The board loading section comprises a board feeding conveyor  14  which conveys boards  5  into the reduced-pressure chamber  11  through a clearance between the stationary part  11   a  and the movable part  11   d . In the description below, the clearances between the stationary part  11   a  and the movable part  11   d  are distinguished from each other as a board loading port  15  (in the board loading section) and a board unloading port (in the board unloading section). 
     Further, a clearance between the movable parts  11   b  and  11   d  of the reduced-pressure chamber  11  to feed a base film  2  without resists in the processing areas between boards (hereinafter abbreviated as processed base film  2 ) into the reduced-pressure chamber  11  is called a film loading port  17   a . Similarly, a clearance between the stationary part  11   a  and the movable part  11   c  of the reduced-pressure chamber  11  to feed a processed base film  2  into the reduced-pressure chamber  11  is called a film loading port  17   b.    
     The processed base films  2  are fed into the reduced-pressure chamber  11  through the respective film loading ports  17   a  and  17   b , are conveyed further with the film body in contact with the rollers  18   a  and  18   b  and tension rollers  19   a  and  19   b , which control the tension of each base film  2  in said reduced-pressure chamber  11 , are further conveyed through a pair of lamination rollers  20   a  and  20   b  with a board sandwiched between two pieces of resist on the base films, and then are ejected out of the chamber  11  through the board unloading port  16 . The lamination roller  20   a , the clamper  21   a , the roller  18   a  and the tension roller  19   a  are disposed above the conveyor surface. The lamination roller  20   b , the clamper  21   b , the roller  18   b  and the tension roller  19   b  are disposed below the conveyor surface. The postfixes of the symbols of these parts are omitted when they are used generically. 
     The roller  18   b , the tension roller  19   b , the lamination roller  20   b , and the damper  21   b  are mounted on the stationary part  11   d  of the reduced-pressure chamber  11  and will not move up and down relative to the stationary part  11   a . On the other hand, the roller  18   a , the tension roller  19   a , the lamination roller  20   a , and the damper  21   a  are mounted on the movable part  11   d  of the reduced-pressure chamber  11  and can move up and down together with the movable part  11   d.    
     When a board  5  is fed by the conveyor  14  into the reduced-pressure chamber  11  through the board loading port  15 , the board  5  is conveyed in the reduced-pressure chamber  11  by a board edge clamping means which is not visible in the figure. For easy comprehension of lamination, boards  5  are identified by postfixes  5   a  (for boards which are loaded into the reduced-pressure chamber  11 ),  5   b  (for a board which has been loaded into the reduced-pressure chamber  11  and is ready to be laminated),  5   c  (for a board which is laminated with resist films  3  in the reduced-pressure chamber  11 ),  5   d  (for a laminated board whose base films  2  are still connected with the succeeding board  5   c ), and  5   e  (for a laminated board whose base films  2  are cut out). 
     The control means  100  calculates the quantity of dry film  1  to be fed, using the output of an encoder (which is invisible in the figure) mounted on the shaft of the dry film roll  1 . The control means  100  also determines the length of the base film  2  in the reduced-pressure chamber  11 . For example, the length of the base film  2  in the reduced-pressure chamber  11  is equal to the length of four boards having resist  3  when the processing area  10  of the base film  2  between boards is just at the film loading port  17 . When the processing area  10  of the base film  2  between boards is just at the film loading port  17 , the control means  100  stops the feed of the boards  5  into the reduced-pressure chamber  11  and actuates the cylinder  12   a  to move the movable part  11   b  down toward the movable part  11   d . When the movable part  11   b  touches the processing area  10  of the base film  2  between boards on the vacuum seal  13  of the movable part  11   d , the cylinder  12   a  further works to cause the movable part  11   b  to push the movable part  11   d  together with the lamination roller  20   a , the clamper  21   a , the roller  18   a , and the tension roller  19   a  until the movable part  11   d  touches the vacuum seal  13  of the stationary part  11   a . In this state, the movable part  11   d  at the board unloading section  16  touches the processing area  10  of the base film  2  between boards on the stationary part  11   a.    
     In other words, the control means  100  actuates the cylinder  12  to hermetically close the reduced-pressure chamber  11 . At the same time, the control means  100  causes the damper  21  to clamp the board  5   c  and the damper  22  outside the reduced-pressure chamber  11  to clamp the board  5   d.    
     Then, the reduced-pressure chamber  11  is evacuated down to a desired degree of vacuum through a vacuum port (invisible in the figure) using a vacuum means which is not visible in the figure. The rollers  18  and the tension rollers  19  are moved perpendicularly to the movement of the boards  5   c  so that the distance between the resist  3  and the rear end (edge) of the board  5   b  facing the board loading port  15  (hereinafter referred to as the rear end of the board) may be wider than the distance between the resist  3  and the front end of the board  5   b  facing the board unloading port  16  (hereinafter referred to as the front end of the board). When the reduced-pressure chamber  11  is closed, the control means  100  working to feed the dry film  1  temporarily stops feeding the dry film  1  as the processing area  10  of the base film  2  between boards is chucked at the film loading port  17   a . Then, the control means  100  moves the rollers  18  and the tension rollers  19  so that a section of base film longer than at least the length of two boards (four boards in this embodiment) may exist in the reduced-pressure chamber  11  when the chamber  11  is closed. In other words, the control means  10  works as a film length control mechanism. 
     The optimum length of the base film existing in the reduced-pressure chamber  11  when the chamber  11  is closed (equivalent to the length of four boards in this embodiment) is determined in consideration of the fact that a longer film length left in the chamber requires a wider chamber space and more evacuation time although it makes the tension control easier and that a shorter film length left in the chamber after lamination makes the tension control harder. 
     When the reduced-pressure chamber  11  reaches the preset degree of vacuum, the lamination rollers  20  are positioned as indicated by dotted circles in FIG. 2, and then they move towards roller positions indicated by the solid circles. During this movement from the front board end to the rear board end with the chamber in the vacuum state, the lamination rollers  20  having a heating means attach the resist  3  evenly to the board surfaces with heat and pressure. This lamination causes no air bubbles or wrinkles in the laminated resist films. 
     After lamination is complete, the lamination rollers  20  go back to the roller positions indicated by dotted circles in FIG.  2 . 
     Referring to FIG. 1 again, the laminated board unloading section will be explained. This unloading section comprises a board-edge transfer means (invisible in FIG.  1 ), a clamper  22 , a base film removing means (invisible in FIG.  1 ), and a clamper  23  downstream of the board unloading port  16  outside the reduced-pressure chamber  11 . 
     When the lamination rollers  20  go back to the roller positions indicated by dotted circles (invisible in FIG.  2 ), the control means  100  stops the vacuum means (invisible in FIG.  1 ), releases the clamper  21  in the reduced-pressure chamber  11  and the clamper  22 , outside the reduced-pressure chamber  11 , and actuates the cylinders  12   a  and  12   b  to open the reduced-pressure chamber  11  as indicated in FIG.  1 . At this time point, lamination of the resist films  3  onto the board  5   b  is completed. 
     Outside the chamber  11 , the front end (edge) of the laminated board  5   d  is clamped by the clamper  23  (indicated by dotted lines) and the clamper  23  moves right (in the figure) by the length of one board. 
     As the damper  23  moves right, the laminated boards  5   b  and  5   c  having resists attached to them are moved towards the board unloading port  16  by the board edge clamping means (invisible in FIG. 1) in the reduced-pressure chamber  11 . When the rear end of the laminated board  5   c  comes into alignment with the dampers  21 , the control means  100  feeds a new part of the dry film  1  into the reduced-pressure chamber  11  through the film loading port  17 , and a new board  5   a  is introduced through the board loading port  15  from outside the reduced-pressure chamber  11 . 
     The board  5   c  whose rear end is between the dampers  21  in the reduced-pressure chamber  1  moves to the position of the board  5   d  in the board unloading section and the front and rear ends of the board are clamped by the dampers  22 . These dampers work as an unloading mechanism which can hold at least two laminated boards. 
     The clampers holding the front end of the board are disposed just upstream of a base film removing means (invisible in FIG.  1 ). While the dampers  23  clamp the board  5   e  at the damper position indicated by solid lines, the base film removing means, for example, a vacuum-pickup means (invisible in FIG. 1) vacuum-picks the base film in the processing area between boards (at the front end of the board  5   d ). As the base film  2  already has perforations in the processing area  10  between boards made by the roulette type device, the processing area  10  between boards is easily removed by vacuum-picking, and the boards  5   d  and  5   e  are separated from each other. 
     Then, the dampers  23  release the board and the board edge clamping means (invisible in FIG. 1) sends the board  5   e  to the succeeding processes. After this, the dampers  23  return to the initial position and move to the front end of the board  5   d . The dampers  22  and  23  clamp the board  5   d . Another new board  5   a  is fed for continuous lamination. 
     As explained above, the embodiments shown in FIG.  1  and FIG. 2 are hermetically sealed at the processing areas  10  of the base films  2  between boards, and vacuum seals are provided at the film loading port  17   a , formed by the movable parts  11   b  and  11   d , and at another film loading port  17   b , formed by the movable part  11   c  and the stationary part  11   a.    
     Similarly, the board unloading port  16  formed by the movable part  11   d  and the stationary part  11   a  is hermetically sealed at the processing area  10  of the base film  2  between boards by the vacuum seal  13 . With this hermetical sealing, the reduced-pressure chamber may be easily evacuated to a desired degree of vacuum, which is retained during lamination. Further, since the roll of dry film  1  is provided outside the reduced-pressure chamber  11 , the chamber  11  can be smaller and the desired degree of vacuum can be quickly obtained. 
     Further, since this embodiment feeds resist films into the reduced-pressure chamber  11  without applying any frictional force to or effecting contamination of the resist  3  to be attached to the boards  5 , this embodiment can keep the boards clean during lamination in the reduced-pressure chamber, and thus greatly reduce the number of faulty laminated boards. 
     Also, when the laminated boards  5  are ejected from the reduced-pressure chamber  11 , they are protected against damage by frictional forces from the vacuum seal, since the boards do not touch the vacuum seal. Further, this extends the service life of the vacuum seal  13  and does not require frequent replacement of the vacuum seal  13 . 
     Another embodiment of the present invention will be explained with reference to FIG.  3 . 
     FIG. 3 is a schematic sectional view of a vacuum film-laminating apparatus which represents a second embodiment of the present invention. In contrast to the previous embodiment, this embodiment moves the boards  5  in the reduced-pressure chamber  32  during lamination. The vacuum film-laminating apparatus of this embodiment mainly comprises a film loading section, a reduced-pressure section, a board loading section, and a laminated board unloading section. The film loading section and the board loading section of this embodiment are functionally almost the same as those of the first embodiment shown in FIG.  1  and FIG.  2  and identical symbols are used in the figures to identify the same or similar parts. Their detailed explanation will be omitted here. 
     As seen in FIG. 3, the reduced-pressure section comprises a reduced-pressure chamber  32  having film loading ports  30   a  and  30   b , a board loading port  31   a , and a board unloading port  31   b . A vacuum means (invisible in FIG. 3) is provided for evacuating the reduced-pressure chamber  32  through an evacuation hole (invisible in FIG. 3) on the reduced-pressure chamber  32 . The film loading ports  30   a  and  30   b  of the reduced-pressure chamber  32  are respectively equipped with an inlet valve  33  which can be operated by an opening and closing means, as will be explained later. When the inlet valve opens, the resist  3  and the base film  2  can be fed into the reduced-pressure chamber  32  without touching the port. 
     An example of means and methods for opening and closing the inlet valve  33  in the film loading port  30   a  will be explained with reference to FIG.  4  and FIG.  5 . 
     FIG.  4  and FIG. 5 respectively show a magnified view of the film loading port and its vicinity. FIG. 4 shows the inlet valve in its is open state. FIG. 5 shows a sectional view of a closed inlet valve taken on the line A—A in FIG.  4 . Parts which are functionally identical are given an identical symbol in FIG.  4  and FIG.  5 . 
     As seen from FIG.  4  and FIG. 5, the inlet valve is a hollow member having a deformable sealing material  33 , for example, which is made of an elastic material at its end. The inlet valve is a little wider than the base film  2 . The other end of the inlet valve  33  has an air inlet hole  33 C through which air is supplied to the hollow part of the valve. This air inlet hole  33 C is connected to an air supplying and evacuating means (invisible in FIG.  3 ). Air is taken into or from the inlet valve  33  through this inlet hole  33 C. 
     To open the film loading port  30   a , the inlet valve is evacuated through the air inlet hole  33 C. The deformable sealing-material  33 A shrinks to form a dent in the inlet valve  33  above the film conveying surface as shown in FIG.  4 . When the processed base film  2  reaches a preset position in the reduced-pressure chamber  32 , the processing area  10  of the base film  2  between boards comes under the inlet valve  33 . 
     When air is supplied to the inlet valve  33  through the air inlet port  33 C from the air supplying and evacuating means (invisible in FIG.  3 ), the deformable sealing material expands to touch the base film  2  at the processing area  10  between boards only. In other words, the film loading port  30   a  can be closed completely with the base film  2  in contact with the inlet valve  33  without touching the portion of the resist  3  on the base film  2 . 
     Referring to FIG. 3 again, means for closing the board loading port  31   a  and the board unloading port  31   b  of the reduced-pressure chamber  32  will be explained. 
     The board loading port  31   a  and the board unloading port  31   b  respectively have shutters  34   a  and  34   b  which can move vertically. These shutters  34   a ,  34   b  are driven by a moving means (invisible in FIG. 3) to close the board loading port  31   a  and the board unloading port  31   b  to hermetically seal the reduced-pressure chamber  32 . 
     The processed base films  2  and resists  3  are fed into the reduced-pressure chamber  32  through the film loading ports  30   a  and  30   b , respectively, are conveyed further with the film body in contact with the moving rollers  35   a  and  35   b  and adjusting rollers  36   a  and  36   b  in said reduced-pressure chamber  32 , and are further conveyed through a pair of lamination rollers  37   a  and  37   b  with a board  5  sandwiched between two pieces of resist  3  on the base films  2 . The moving rollers  35   a  and  35   b  are movable left and right (in FIG. 3) by moving means which are invisible in FIG.  3 . Similarly, the lamination rollers  37   a  and  37   b  are movable up and down perpendicularly to the board conveying surface by moving means which are invisible in FIG.  3 . The adjusting rollers  36   a  and  36   b  are fixed at positions located by a preset distance away from the board conveying surface. 
     The inlet valves  33 , the moving rollers  35   a  and  35   b , the adjusting rollers  36   a  and  36   b  and the control means  100  for controlling their movement work together to adjust the length of the film in the reduced-pressure chamber  32  so that a preset length of film (length of at least two boards or more) exists in the chamber  32  when the chamber  32  is closed. 
     The lamination rollers  37   a  and  37   b  which can move vertically toward and away from the board conveying surface have a function to adjust the length of the film which is not in contact with the board in the closed reduced-pressure chamber. 
     The reduced-pressure chamber can contain a board  5   b  to be laminated and laminated boards  5   c  and  5   d  simultaneously. A cutter  38  is provided between the laminated boards  5   c  and  5   d  to cut the base films. Clampers (invisible in FIG. 3) are provided before and after the cutter  38  to hold the laminated boards together with the base films  2 . 
     In this way, the board conveyors  40  and  41  and the dampers work to hold and pickup at least two laminated boards. 
     As explained above, when the processed base film  2  is fed into the reduced-pressure chamber  32  through the film loading port  30   a  and a board  5   a  is carried into the chamber  32  by the board conveyor  14 , the board  5   b  on the board conveyor  39  is moved to the position of board  5   c  and the board  5   c  is moved to the position of the board  5   d  in the reduced-pressure chamber  32 . 
     When the front end of the board  5   b  on the board conveyor  39  reaches a space between the lamination rollers  37   a  and  37   b , the inlet valves  33  close the film loading ports  30 . Further, the shutters  34   a  and  34   b  are moved up by the moving means (invisible in FIG. 3) to close the board loading port  31   a  and the board unloading port  31   b . Thus, the reduced-pressure chamber  32  is closed hermetically. Then, the vacuum means (invisible in FIG. 3) starts to evacuate the chamber  32 . When the vacuum pressure in the reduced-pressure chamber  32  reaches a preset pressure, the lamination rollers  37  start to move toward the board conveyor  39 . In this case, the reduced-pressure chamber  32  contains resist  3  of a length equivalent to the length of two boards or more. 
     While the lamination rollers  37  maintain a pressure on the resists  3  against the board  5   b , the board conveyors  39  and  40  work in synchronism to convey the board  5   b  to the unloading section. At the same time, the moving rollers  35  move right to allow the board  5   b  to be conveyed. 
     In other words, by moving the rollers  35  in synchronism with the movement of the board conveyor  39  while the base film  2  is clamped by the inlet valve  33  in the film loading port  30   a , the lamination rollers  37  can evenly press the base film  2  on the whole surface of the board  5   b  (from the front end to the rear end) with force. At the same time, the lamination rollers  37  containing heating means apply heat to the resist  3  through the base film  2  during lamination. Thus, the resists  3  are attached strongly to the surfaces of the board  5   b  with heat and force. 
     In this case, as the board conveyor  40  also works in synchronism with the board conveyor  39 , the laminated board  5   c  is carried to the board position  5   d . When the board  5   d  is detected by a board detecting means  82 , such as a photo sensor, in the board unloading port  31   b  or its vicinity, the upper and lower dampers (invisible in FIG. 3) vertically clamp the front and rear ends of the board  5   c . The cutter  38  cuts the base film  2  in the processing area  10  between boards  5   c  and  5   d  to separate the boards  5   c  and  5   d  from each other. At the end of cutting, the shutters  34   a  and  34   b  and inlet valves  33   a  and  33   b  are opened. 
     When the reduced-pressure chamber  32  is opened to the atmosphere, the board conveyors  41  and  42  are driven to send the board  5   d  to the board position  5   e  outside the reduced-pressure chamber  32 . In this case, the board conveyors  39  and  40  are not driven, and the chamber  32 , which is open to the atmosphere, still contains the laminated board  5   c.    
     When the board detecting means  82  in the board unloading port  31   b  or its vicinity detects no board in the board position  5   d  the board conveyor  14  starts to feed a new board  5   a  into the reduced-pressure chamber  32  and positions it in the board position  5   b . Then, the reduced-pressure chamber  32  is closed and starts to effect another lamination. 
     As explained above, in accordance with the present invention, the inlet valve  33  presses the base film  2  at the processing area  10  between boards to hermetically close the reduced-pressure chamber  32  without touching any part of the resist  3 . Therefore, the boards  5  will never be contaminated, by any dust of resist  3  and can be laminated perfectly. 
     The cutting of the cover film after lamination can be done outside the reduced-pressure chamber  32  to keep the inside of the reduced-pressure chamber  32  clean. 
     An embodiment similar to FIG. 3, which cuts the cover film outside the reduced-pressure chamber  32 , will be explained with reference to FIG.  6 . 
     FIG. 6 is an enlarged sectional view of the board unloading section of the reduced-pressure chamber  32  and its vicinity. The parts in FIG.  3  and FIG. 6 are assigned identical symbols when they are functionally identical. This embodiment, unlike the embodiment in FIG. 3, has an inner cylinder  42  in the board exit side (board unloading part)  31   b  of the reduced-pressure chamber  32 . A shutter  34   b  is provided on the outer side of the inner cylinder  42 , and a cutter  44  is provided at the outer side of the shutter  34   b . Further, a board conveyor  40   a  which can move together with the inner cylinder  42  is provided on the downstream side of the board conveyor which holds the board  5   c  in the reduced-pressure chamber  32 . 
     As shown in FIG. 6, the inner cylinder  42  can be moved (by a moving means which is invisible in FIG. 6) outwards in the reduced-pressure chamber  32  during lamination. The hermetical sealing of the reduced-pressure chamber  32  is assured by the sealing material  43  provided between the reduced-pressure chamber  32  and the inner cylinder  42 . 
     The shutter  34   b  provided on the board exit side  31   b  of the inner cylinder  42  is driven up and down by a moving means which is invisible in FIG.  6  and can also be moved left and right as the inner cylinder  42  moves. The cutter  44  is placed at the right side (on the atmosphere side) of the shutter  34   b  which is on the board exit side of the reduced-pressure chamber  32 . In FIG. 6, the inner cylinder  42  in solid lines indicates the cylinder  42  which is ready to move and the inner cylinder  42  in dotted lines indicates the cylinder  42  which moved furthest. When the inner cylinder  42  moves, the board conveyor  40   a  having the board  5   c  moves right separate from the board conveyor  40 . The board  5   c  is carried to the board position  5   d . In the descriptions below, the inner cylinder  42  before movement is distinguished from the inner cylinder  42  after movement. 
     Unlike the embodiment shown in FIG. 3, the embodiment in FIG. 6 has a board detecting means (invisible in FIG. 6) which detects the front end of the board  5   c  in the vicinity of the board unloading port  31   b  of the inner cylinder  42 . When the board detecting means detects the front end of a laminated board  5   c , the inner cylinder  42  and the board conveyor  40   a  having the laminated board  5   c  move right (in the figure) separate from the board conveyor  40 . 
     When the inner cylinder  42  reaches the rightmost end (indicated by the dotted lines), the shutter  34   b  moves down to open the reduced-pressure chamber  32 . In this case, the film loading port  30  of the reduced-pressure chamber  32  is closed as shown in FIG.  3  and the base film  2  is located in the dotted position (in FIG. 3) by the movement of the moving roller  35   a.    
     Just when the shutter  34   b  is opened, the laminated board  5   d  is held in the dotted position  5   d  on the board conveyor  40   a , but the board conveyor  40   a  starts to convey the board sd rightward and at the same time, the inner cylinder  42  moves back to the home position together with the open shutter  34   b  and the cutter  44 . Simultaneously, a board supporting member (invisible in FIG. 6) is inserted under the laminated board  5   d  from the right of the figure to support the laminated board. Therefore, when the inner cylinder  42  returns to its home position, the laminated board  5   d  is left on the supporting member from the board conveyor  40   a.    
     When the inner cylinder  42  moves back (left) to the home position (indicated by the solid lines) with the shutter  34   b  (or the reduced-pressure chamber  32 ) open, the board conveyor  40   a  which moved back together with the inner cylinder  42  stops just before the front end of a board  5   c  on the board conveyor  40 . The cutter  44  cuts the base film  2  in the processing area between the laminated boards  5   c  and  5   d . Then the inner cylinder  42  returns to the home position (indicated by the solid lines in FIG. 6) without actuating the board conveyor  40  and the shutter  34   b  closes. 
     As explained above, since the embodiment in FIG. 6 cuts the cover film outside the reduced-pressure chamber  32 , the embodiment can prevent any cutting dust from entering into the reduced-pressure chamber  32 . Even when the cutting dust is sucked into the reduced-pressure chamber  32  (as the cover film cutting is done in the atmosphere), it is exhausted from the reduced-pressure chamber  32  during lamination under a vacuum pressure. Therefore, a clear lamination can be assured. 
     Although the embodiments in FIG.  1  through FIG. 6 attach a cover film  4  having resist  3  on each surface of a board  5 , there will be no problem when the embodiments attach a cover film having resist on one of the board surfaces only. Further, the boards can be carried by edge-clamping transfer means instead of the conveyors which convey boards on them. 
     Further, the embodiments in FIG.  1  through FIG. 6 respectively used a roulette type device  7  to apply perforations to the base film  2  in the film loading section and remove a resist portion from the processing area  10  of the base film  2  between boards. However, it is possible to leave cover films in the processing areas between boards instead of removing cover films completely before feeding them into the reduced-pressure chamber. In this case, a dry film removing means is required to remove the resist  3  and the cover film  4  left in the processing areas between boards together with the base film  2 . 
     Further, it is possible to make the processing areas  10 , non-laminated areas, between boards on the base film  2  by cutting out the resist  3  and the cover film  4 , perforating the base film  2 , removing all cut-out cover films, and applying a tape piece as wide as the processing area between boards transversely onto the resist in the processing area between boards. The set of base film, resist, and tape in the processing area between boards is removed after lamination is complete to make the laminated boards separated. 
     It is also possible to detect the processing area  10  between boards in the film loading port by an optical sensor provided near the film loading port (by detecting a change in the intensity of light reflected in this area) or to detect it visually using an image sensor. 
     In accordance with the vacuum film laminating apparatus of the present invention, films and boards can be fed into the reduced-pressure chamber without being damaged and contaminated. The reduced-pressure chamber can obtain the desired degree of vacuum in a short time and films and boards can be continuously laminated in a very clear environment.