WO2007129844A1

WO2007129844A1 - System and method for attaching stiffening plate on flexible printed circuit board

Info

Publication number: WO2007129844A1
Application number: PCT/KR2007/002217
Authority: WO
Inventors: Se Young Kim; Cheon Hee Kim
Original assignee: Seho Robot Industries Co., Ltd
Priority date: 2006-05-04
Filing date: 2007-05-04
Publication date: 2007-11-15

Abstract

A stiffening plate attachment system and method includes a worktable for supporting the flexible printed circuit board. A tray is positioned on an upstream side of the worktable to receive a stiffening plate laminate having a stiffening plate, an adhesive agent layer and a release sheet laminated one atop another. A release sheet peeling device is provided between the worktable and the tray to move an adhesive tape coated with an adhesive agent in such a way that the adhesive agent adheres to and peels off the release sheet of the stiffening plate laminate. A robot is provided between the worktable and the tray to pick up the stiffening plate laminate and to move the stiffening plate laminate from the tray to above the adhesive agent of the adhesive tape so that the release sheet can be bonded to and peeled off by the adhesive agent of the adhesive tape.

Description

[SPECIFICATION]

[Title of the Invention]

SYSTEM AND METHOD FOR ATTACHING STIFFENING PLATE ON FLEXIBLE PRINTED CIRCUIT BOARD

[Field of the Invention]

The present invention relates to a system and method for attaching a stiffening plate to a flexible printed circuit board and, more particularly, to a stiffening plate attachment system and method for use with a flexible printed circuit board that can automatically attach a stiffening plate to a flexible printed circuit board.

[Background Art]

A flexible printed circuit board (hereinafter often referred to as "FPCB") is constructed by forming a printed circuit on a heat-resistant plastic film made of, e.g., polyester or polyimide. The FPCB exhibits flexibility great enough to ensure that it can be subjected to bending, twisting, folding or other deformation. Thus, the FPCB makes it possible to efficiently utilize a space and also to three-dimensionally arrange wiring lines.

Electronic parts are mounted to a pattern of the FPCB by means of a surface mounting machine, a chip mounter and so forth. In an effort to stiffen or reinforce the FPCB, a stiffening plate formed of a polyimide film, a glass epoxy film or the like is attached to a region of the FPCB to which the electronic parts are mounted. In order for the stiffening plate to be attached to the FPCB, an adhesive agent is coated on a rear surface of the stiffening plate and is protected by a release sheet. The task of attaching the stiffening plate is manually performed for the most part by an operator. The operator peels off the release sheet from the stiffening plate and attaches the stiffening plate to a region of the FPCB by use of the adhesive agent.

However, the operator's task of manually attaching the stiffening plate to the FPCB in this manner is quite laborious and time-consuming, thus posing a problem in that production costs are greatly increased together with reduced productivity. Furthermore, during the time when the operator peels off the release sheet, the adhesive agent is contaminated by foreign materials adhering to the hands of the operator, such as dusts, moistures and the like. This reduces bondability of the adhesive agent and leads to bad attachment .

The operator should attach the stiffening plate by accurately aligning it with a contour line written on the FPCB while seeing the contour line or mark with naked eyes. However, it is often the case that, due to the operator's error, the stiffening plate is not attached to an accurate position but attached out of alignment with the contour line. Bad attachment of the stiffening plate causes a great hindrance in mounting electronic parts to the FPCB. In particular, throughout the whole FPCB production line, the process of attaching the stiffening plate becomes a bottleneck process that reduces a production speed. Thus, the stiffening plate attachment process is a major cause of impeding productivity improvement. Accordingly, there has been a demand for development of a system and method capable of accurately attaching the stiffening plate to the FPCB. However, a system and method that can comply with the demand has not been developed thus far .

[Detailed Description of the Invention] [Technical Problems]

In view of the above-noted and other problems inherent in the prior art, it is an object of the present invention to provide a stiffening plate attachment system and method for use with a flexible printed circuit board that can automate a series of stiffening plate processing steps including a peeling step, a moving step, an alignment step and an attachment step, thereby saving production costs and greatly improving productivity. Another object of the present invention is to provide a stiffening plate attachment system and method for use with a flexible printed circuit board that can accurately attach a stiffening plate to a surface of a flexible printed circuit board.

A further object of the present invention is to provide a stiffening plate attachment system and method for use with a flexible printed circuit board that can prevent an adhesive agent coated on a stiffening plate from being contaminated by foreign materials.

[Solution to the Technical Problems]

In one aspect of the present invention, there is provided a stiffening plate attachment system for use with a flexible printed circuit board, including: a worktable for supporting the flexible printed circuit board; a tray positioned on an upstream side of the worktable for receiving a stiffening plate laminate having a stiffening plate, an adhesive agent layer and a release sheet laminated one atop another; a release sheet peeling means provided between the worktable and the tray for moving an adhesive tape coated with an adhesive agent in such a way that the adhesive agent adheres to and peels off the release sheet of the stiffening plate laminate; and a robot provided between the worktable and the tray for picking up the stiffening plate laminate and moving the stiffening plate laminate from the tray to above the adhesive agent of the adhesive tape so that the release sheet can be bonded to and peeled off by the adhesive agent of the adhesive tape, the robot adapted to move the stiffening plate from the adhesive tape to above the flexible printed circuit board and to attach the stiffening plate to the flexible printed circuit board, the robot adapted to make linear reciprocating movement in X- axis, Y-axis and Z-axis directions and rotational movement about a Z-axis.

In another aspect of the present invention, there is provided a stiffening plate attachment method for use with a flexible printed circuit board, including the steps of: preparing the flexible printed circuit board; preparing a stiffening plate laminate having a stiffening plate, an adhesive agent layer and a release sheet laminated one atop another; preparing an adhesive tape coated with an adhesive agent capable of adhering to and peeling off the release sheet of the stiffening plate laminate; causing the release sheet of the stiffening plate laminate to adhere to the adhesive agent of the adhesive tape; moving the stiffening plate laminate and the adhesive tape 122 in such a way that the release sheet is peeled off from the stiffening plate laminate; and attaching the stiffening plate to the flexible printed circuit board through the adhesive agent layer. [Advantageous Effects]

The stiffening plate attachment system and method for use with a flexible printed circuit board in accordance with the present invention provides an effect that it is possible to automate a series of stiffening plate processing steps including a peeling step, a moving step, an alignment step and an attachment step, thereby saving production costs and greatly improving productivity. Another effect provided by the present system and method is that the stiffening plate can be accurately attached to a surface of the flexible printed circuit board by processing images of the flexible printed circuit board and the stiffening plate acquired by first and second cameras. A further effect provided by the present system and method is that it is possible to prevent an adhesive agent coated on the stiffening plate from being contaminated by foreign materials.

[Brief Description of the Drawings] Fig. 1 is a front elevational view showing a stiffening plate attachment system in accordance with a first embodiment of the present invention.

Fig. 2 is a top plan view showing the stiffening plate attachment system in accordance with the first embodiment of the present invention. Fig. 3 is a perspective view illustrating a stiffening plate laminate and an adhesive tape processed in the stiffening plate attachment system in accordance with the first embodiment of the present invention. Fig. 4 is a block diagram illustrating a controller for controlling the stiffening plate attachment system in accordance with the first embodiment of the present invention.

Fig. 5 is a block diagram illustrating a worktable and a vacuum head of a robot respectively connected to a vacuum pump in the stiffening plate attachment system in accordance with the first embodiment of the present invention.

Fig. 6 is a section view showing the worktable employed in the stiffening plate attachment system in accordance with the first embodiment of the present invention.

Fig. 7 is a section view showing a Z-axis rotary actuator and a Z-axis linear actuator employed in the stiffening plate attachment system in accordance with the first embodiment of the present invention.

Figs. 8 through 11 are views for explaining a release sheet peeling operation performed by a release sheet peeling device and a vacuum head of a robot in the stiffening plate attachment system in accordance with the first embodiment of the present invention. Fig. 12 is a flowchart for explaining a stiffening plate attachment method according to a first embodiment of the present invention, which is performed by the stiffening plate attachment system in accordance with the first embodiment of the present invention.

Fig. 13 is a front elevational view showing a stiffening plate attachment system in accordance with a second embodiment of the present invention.

Fig. 14 is a top plan view showing the stiffening plate attachment system in accordance with the second embodiment of the present invention.

Fig. 15 is a block diagram illustrating a controller for controlling the stiffening plate attachment system in accordance with the second embodiment of the present invention.

Fig. 16 is a block diagram illustrating a worktable, a vacuum head of a first robot and a vacuum head of a second robot respectively connected to a vacuum pump in the stiffening plate attachment system in accordance with the second embodiment of the present invention.

Figs. 17 through 20 are views for explaining a release sheet peeling operation performed by a release sheet peeling device and a vacuum head of a first robot in the stiffening plate attachment system in accordance with the second embodiment of the present invention. Figs. 21 and 22 are views for explaining a release sheet bonding operation performed by a release sheet peeling device and an elastic plate in the stiffening plate attachment system in accordance with the second embodiment of the present invention.

Fig. 23 is a flowchart for explaining a stiffening plate attachment method according to a second embodiment of the present invention, which is performed by the stiffening plate attachment system in accordance with the second embodiment of the present invention.

Figs. 24 through 27 are views for explaining a release sheet peeling operation performed by a release sheet peeling device and a vacuum head of a first robot in a stiffening plate attachment system in accordance with a third embodiment of the present invention.

[Best Mode for Carrying out the Invention]

Preferred embodiments of a stiffening plate attachment system and method for use with a flexible printed circuit board in accordance with the present invention will now be described in detail with reference to the accompanying drawings .

Referring first to Figs. 1 to 7 and 8 to 11, there is shown a stiffening plate attachment system in accordance with a first embodiment of the present invention. As shown in Figs. 1 and 2, the stiffening plate attachment system of the first embodiment is designed to peel off a stiffening plate 21 from a stiffening plate laminate 20 and attach the same to one surface of a flexible printed circuit board or FPCB 10, e.g., around through-holes 11 of the FPCB 10 into which leads of electronic parts are to be inserted. The reason for attaching the stiffening plate 21 is to reinforce the FPCB 10. On one surface of the FPCB 10, there is written a plurality of contour lines 12 or marks each representing a target attachment area of the stiffening plate 21. As can be seen in Fig. 2, the stiffening plate 21 is attached in alignment with each of the contour lines 12 on the FPCB 10.

Referring to Figs. 2 and 3, the stiffening plate laminate 20 consists of the stiffening plate 21, an adhesive agent layer 22 and a release sheet 23. The adhesive agent layer 22 is coated on one surface of the stiffening plate 21 and is protected by the release sheet 23. The release sheet 23 consists of, e.g., a paper and silicon coated on one surface of the paper to make the latter peelable. The stiffening plate laminate 20 consisting of the stiffening plate 21, the adhesive agent layer 22 and the release sheet 23 in this way has the same configuration as that of a single side tape well-known in the art. The stiffening plate laminate 20 is supplied in a state that it is received in each of recesses 31 of a tray 30 with the stiffening plate 21 faced upwardly. The recesses 31 of the tray 30 are arranged in rectangular coordinates.

Referring to Figs. 1, 2, 5 and 6, the stiffening plate attachment system of the first embodiment includes a frame 100 and a worktable 110 installed on a downstream side of the frame 100 so that the FPCB 10 can be placed on the worktable 110. A plurality of suction holes 111 is formed on a top surface of the worktable 110. The suction holes 111 are connected to an air-sucking vacuum pump 114 via a first air pipeline 112 and a manifold 113. The vacuum pump 114 may be replaced by an air blower that can draw and discharge an air. A first solenoid valve 115 for controlling air flow is provided on the first air pipeline 112. A heater 116 is arranged within the worktable 110. If the FPCB 10 is heated by means of the heater 116, the adhesive agent layer 22 making contact with the FPCB 10 is melted to thereby attach the stiffening plate 21 to the FPCB 10. The heater 116 may be formed of a heating wire built in the worktable 110.

Referring again to Figs. 1 and 2, the stiffening plate attachment system of the first embodiment includes a release sheet peeling device 120 installed between a downstream side of the tray 30 and an upstream side of the worktable 110. The release sheet peeling device 120, which serves to peel off the release sheet 23 from the stiffening plate 21, includes an adhesive tape roll 121, an unwinder 130, a rewinder 140 and a support table 150. The adhesive tape roll 121 consists of an adhesive tape 122 and an adhesive agent 123 coated on a surface of the adhesive tape 122 so that it can adhere to the release sheet 23 of the stiffening plate laminate 20 to peel off the same. The adhesive agent 123 of the adhesive tape roll 121 has a bonding force greater than that of the adhesive agent layer 22 of the stiffening plate laminate 20.

The adhesive tape roll 121 is mounted to a reel 131 of the unwinder 130. The reel 131 of the unwinder 130 is rotatably mounted to an upstream side of the frame 100 in such a manner that, when the reel 131 is rotated, the adhesive tape 122 can be continuously unwound from the adhesive tape roll 121. The rewinder 140 has a reel 141 rotatably mounted between the worktable 110 and the reel 131 of the unwinder 130. A tip end of the adhesive tape 122 unwound from the reel 131 of the unwinder 130 is secured to the reel 141 of the rewinder 140.

The support table 150 is mounted between and above the unwinder 130 and the rewinder 140 in such a fashion as to support a lower surface of the adhesive tape 122. First and second round portions 151 and 152 for smoothly guiding movement of the adhesive tape 122 are formed at opposite ends of the support table 150 adjoining to the unwinder 130 and the rewinder 140. The release sheet 23 bonded to the adhesive agent 123 of the adhesive tape 122 is moved along a top surface of the support table 150, at which time the direction of movement of the release sheet 23 is turned toward the reel 141 of the rewinder 140 by the first round portion 151 of the support table 150. The release sheet 23 whose movement direction is changed in this way is smoothly peeled off from the adhesive agent layer 22 of the stiffening plate laminate 20.

The reel 141 of the rewinder 140 is rotated by means of a driving device 160. The driving device 160 includes a servo motor 161 installed in an upper portion of the frame 100 adjacent to the reel 141 of the rewinder 140 for providing drive power and a belt transmission mechanism 162 for transmitting the drive power of the servo motor 161 to the reel 141. If necessary, the belt transmission mechanism 162 may be replaced by a gear device that can deliver the drive power of the servo motor 161 to the reel 141. Furthermore, the drive power of the servo motor 161 may be transmitted to the reel 131 of the unwinder 130 by use of another belt transmission mechanism to simultaneously rotate the reel 131 of the unwinder 130 and the reel 141 of the rewinder 140, if such a need exists. Guide rollers for guiding the movement of the adhesive tape 122 may be provided between the unwinder 130 and the support table 150 and between the rewinder 140 and the support table 150.

Referring to Figs. 1, 2, 6 and 7, the stiffening plate attachment system of the first embodiment includes a robot 200 installed in the upper portion of the frame 100. The robot 200 consists of an X-axis linear actuator 210, a Y- axis linear actuator 220, a Z-axis rotary actuator 230, a Z- axis linear actuator 240 and a vacuum suction device 250.

The X-axis linear actuator 210 includes a guide rail 211, a servo motor 212, a lead screw 213, a ball nut block 214 and a carriage 215. The guide rail 211 extends in an X- axis direction of the frame 100, i.e., in a moving direction of the stiffening plate 21. A guide slot 211a is formed on an outer surface of the guide rail 211 to extend in a longitudinal direction thereof. The servo motor 212 is mounted within the guide rail 211. The lead screw 213 is also mounted within the guide rail 211 so that it can be rotated by the servo motor 212. The ball nut block 214 is mounted in such a way that it can be slid along the inner side of the guide rail 211 and can also be threadedly moved along the lead screw 213. The carriage 215 is mounted to the outer side of the guide rail 211 to make linear reciprocating movement along the guide rail 211 and is connected to the ball nut block 214 through the guide slot 211a of the guide rail 211. The Y-axis linear actuator 220 includes a guide rail 221, a servo motor 222, a lead screw 223, a ball nut block 224 and a carriage 225, which correspond exactly to the guide rail 211, the servo motor 212, the lead screw 213, the ball nut block 214 and the carriage 215 of the X-axis linear actuator 210. The guide rail 221 of the Y-axis linear actuator 220 is mounted to the carriage 215 of the X-axis linear actuator 210 in a Y-axis direction. Each of the X- axis and Y-axis linear actuators 210 and 220 may consist of an air cylinder, a carriage linearly reciprocated by the air cylinder and a linear motion guide for guiding the linear reciprocating movement of the carriage.

As shown in Fig. 7, the Z-axis rotary actuator 230 includes a servo motor 231, first to third hollow shafts 232, 233 and 234, a pin 235 and a belt transmission mechanism 236. The servo motor 231 is mounted to the carriage 225 of the Y- axis linear actuator 220.

The first hollow shaft 232 is arranged upright in a parallel relationship with a shaft 231a of the servo motor 231 and the second hollow shaft 233 displaceably mounted within the first hollow shaft 232. Slots 232a and 233a communicating with each other are formed on the outer surfaces of the first hollow shaft 232 and the second hollow shaft 233 to extend in a longitudinal direction thereof. The third hollow shaft 234 is mounted within the second hollow shaft 233. A hole 234a is formed on the outer surface of the third hollow shaft 234 in a communicating relationship with the slots 232a and 233a of the first hollow shaft 232 and the second hollow shaft 233. The pin 235 is inserted into the hole 234a of the third hollow shaft

234 through the slots 232a and 233a of the first hollow shaft 232 and the second hollow shaft 233 so that it can be displaced along the slot 232a of the first hollow shaft 232.

The belt transmission mechanism 236 includes a driving pulley 236a fixed to the shaft 231a of the servo motor 231, a driven pulley 236b secured to the outer surface of the first hollow shaft 232 and a belt 236c wound around the driving pulley 236a and the driven pulley 236b. If the drive power of the servo motor 231 is transmitted to the first hollow shaft 232 via the driving pulley 236a, the belt 236c and the driven pulley 236b of the belt transmission mechanism 236, the second and third hollow shafts 233 and 234 coupled to the first hollow shaft 232 by means of the pin 235 are rotated together with the first hollow shaft 232. The Z-axis linear actuator 240 consists of an air cylinder 241 which in turn has a cylinder housing 241a and a pair of cylinder rods 241b. The cylinder housing 241a of the air cylinder 241 is mounted upright to the carriage 225 and the cylinder rods 241b are fitted to both sides of the cylinder housing 241a so that they can be extended and retracted with respect to the cylinder housing 241a. The upper ends of the cylinder rods 241b are connected to each other by means of a joint plate 242. The upper end of the second hollow shaft 233 is rotatably supported by a bearing 243 at the center of the joint plate 242. The middle portion of the first hollow shaft 232 is rotatably supported by a pair of bearings 244 in the upper and lower portions of the cylinder housing 241a.

If the cylinder rods 241b are extended or retracted in a Z-axis direction and the joint plate 242 is moved up or down by means of the air cylinder 241, the second hollow shaft 233 and the third hollow shaft 234 are also moved up and down therewith. The second hollow shaft 233 is slid along the inner surface of the first hollow shaft 232, while the first hollow shaft 232 is restrained by the cylinder housing 241a of the air cylinder 241. Just like the X-axis and Y-axis linear actuators 210 and 220, the Z-axis linear actuator 240 consists of a guide rail, a servo motor, a lead screw, a ball nut block and a carriage. Referring to Figs. 5 and 7, the vacuum suction device 250 has a vacuum head 251 mounted to a lower end of the third hollow shaft 234 so that it can pick up the stiffening plate 21 of the stiffening plate laminate 20. The vacuum head 251 is connected to the vacuum pump 114 via the third hollow shaft 234, a second air pipeline 252 and the manifold 113. A heater for applying heat to the adhesive agent layer 22 of the stiffening plate 21 may be provided inside the vacuum head 251, in which case it is possible to eliminate the heater 116 installed within the worktable 110. A second solenoid valve 253 for controlling air flow is installed on the second air pipeline 252.

Referring to Figs. 1, 2 and 6, the stiffening plate attachment system of the first embodiment includes an image processing device 300 for taking images of the FPCB 10 and the stiffening plate 21 to control the operation of the robot 200 in such a manner that the robot 200 can align the stiffening plate 21 with each of the contour lines 12 on the FPCB 10. The image processing device 300 consists of a first camera 301, a second camera 302 and a computer 303. The first camera 301 is mounted on the top surface of the worktable 110 and serves to take an image of the stiffening plate 21 picked up by the vacuum head 251 to thereby output an image data thereof. The second camera 302 is mounted to the carriage 225 of the Y-axis linear actuator 220 and serves to take an image of the FPCB 10 suction-held by the worktable 110 to thereby output an image data thereof. The first camera 301 and the second camera 302 may consist of a charged coupled device camera. The computer 303 is provided with a monitor 304, a microprocessor and an input device. The computer 303 processes the image data of the FPCB 10 and the image data of the stiffening plate 21 according to a pre-stored program and outputs signals for controlling the operation of the robot 200 so that the robot 200 can align the stiffening plate 21 with one of the contour lines 12 on the FPCB 10.

Referring to Figs. 1, 2 and 4, the stiffening plate attachment system of the first embodiment includes a controller 310 interfaced with the computer 303. By- processing the signals inputted from the computer 303, the controller 310 controls operations of the vacuum pump 114, the first solenoid valve 115, the heater 116, the servo motor 161 of the driving device 160, the servo motor 212 of the X-axis linear actuator 210, the servo motor 222 of the Y-axis linear actuator 220, the air cylinder 241, the second solenoid valve 253 and the first and second cameras 301 and 302. The controller 310 is connected to a key matrix 311 through which an operator can input a command required in controlling the stiffening plate attachment system. Operations of the vacuum pump 114, the first solenoid valve 115, the heater 116, the servo motor 161 of the driving device 160, the image processing device 300 and the robot 200 may be controlled by a program stored in the computer 303 in place of the controller 310.

Now, description will be made with reference to Fig. 12 on a stiffening plate attachment method according to a first embodiment of the present invention, which is performed by the stiffening plate attachment system of the first embodiment set forth above.

Referring collectively to Figs. 1, 2, 6, 8 and 9, the operator prepares the FPCB 10 to be placed on the top surface of the worktable 110 (step SlOO) . The FPCB 10 is laid down on the top surface of the worktable 110 by the operator. In a state that the first solenoid valve 115 is opened, the vacuum pump 114 is driven to generate an air suction force. Thus, an air is drawn through the suction holes 111 of the worktable 110, the first air pipeline 112 and the manifold 113, whereby the FPCB 10 is suction-held on the top surface of the worktable 110. The task of loading and unloading the FPCB 10 may be performed by means of a FPCB handler well-known in the art.

Next, the operator prepares the stiffening plate laminate 20 (step SlOl) . The stiffening plate laminate 20 is received in each of the recesses 31 of the tray 30 in such a way that the stiffening plate 21 is faced upward. The tray 30 is placed on the upstream side of the support table 150.

Then, the operator prepares the adhesive tape 122 coated with the adhesive agent 123 capable of adhering to and peeling off the release sheet 23 of the stiffening plate laminate 20 (step S102) . The adhesive tape roll 121 is mounted to the reel 131 of the unwinder 130 and the adhesive tape 122 is unwound from the adhesive tape roll 121. The adhesive tape 122 thus unwound is moved along the top surface of the support table 150 and wound on the reel 141 of the rewinder 140.

Once the FPCB 10, the stiffening plate laminate 20 and the adhesive tape 122 have been prepared, the release sheet 23 of the stiffening plate laminate 20 is bonded to the adhesive agent 123 of the adhesive tape 122 (step S103) . The robot 200 is operated by manipulating the key matrix 311 of the controller 310. As the servo motor 212 of the X-axis linear actuator 210 is driven, the lead screw 213 is caused to rotate and the ball nut block 214 is threadedly moved along the rotating lead screw 213 while sliding along the guide rail 211. The carriage 215 connected to the ball nut block 214 makes linear reciprocating movement along the guide rail 211, in response to which the Y-axis linear actuator 220, the Z-axis linear actuator 240 and the vacuum head 251 are linearly moved in an X-axis direction together with the carriage 215.

Similarly, if the servo motor 222 of the Y-axis linear actuator 220 is driven, the lead screw 223 is caused to rotate and the ball nut block 224 is threadedly moved along the rotating lead screw 223 while sliding along the guide rail 221. The carriage 225 connected to the ball nut block 224 makes linear reciprocating movement along the guide rail 221, in response to which the Z-axis linear actuator 240 and the vacuum head 251 are linearly moved in a Y-axis direction together with the carriage 225. By the operation of the X-axis linear actuator 210 and the Y-axis linear actuator 220, the vacuum head 251 is placed above and aligned with the stiffening plate laminate 20 received in one of the recesses 31 of the tray 30. Then, the air cylinder 241 is operated to extend the cylinder rods 241b, whereby the vacuum head 251 moves close to the stiffening plate laminate 20. An air suction force is generated by the operation of the vacuum pump 114 and the second solenoid valve 253 is opened under the control of the controller 310. In response, an air is drawn through the second air pipeline 252 and the manifold 113, thereby allowing the stiffening plate laminate 20 to be picked up by the vacuum head 251.

Once the stiffening plate laminate 20 is picked up by the vacuum head 251 as shown in Fig. 8, the air cylinder 241 is operated to retract the cylinder rods 241b. Then, the X- axis and Y-axis linear actuators 210 and 220 are operated to have the vacuum head 251 placed above and aligned with the adhesive tape 122 supported on the support table 150. If the cylinder rods 241b are extended by the operation of the air cylinder 241 as shown in Fig. 9, the release sheet 23 of the stiffening plate laminate 20 picked up by the vacuum head 251 adheres to the adhesive agent 123 of the adhesive tape 122.

Referring to Figs. 1, 2 and 4, once the release sheet 23 of the stiffening plate laminate 20 adheres to the adhesive agent 123 of the adhesive tape 122, the stiffening plate laminate 20 and the adhesive tape 122 are all moved in the same direction and then the moving direction of the adhesive tape 122 is turned to thereby peel off the release sheet 23 from the stiffening plate laminate 20 (step S104) . If the servo motor 161 of the driving device 160 is driven under the control of the controller 310, the reel 141 of the rewinder 140 is rotated to wind the adhesive tape 122 unwound from the adhesive tape roll 121 on the reel 131 of the unwinder 130. The adhesive tape 122 of the adhesive tape roll 121 unwound from the reel 131 of the unwinder 130 is moved along the top surface of the support table 150 and wound around the reel 141 of the rewinder 140.

As can be seen in Fig. 10, the X-axis linear actuator 210 is operated in parallel with the movement of the adhesive tape 122 to thereby displace the Y-axis linear actuator 220, the Z-axis linear actuator 240 and the vacuum head 251 in the moving direction of the adhesive tape 122. Along with the movement of the adhesive tape 122 and the vacuum head 251, the release sheet 23 adhering to the adhesive agent 123 of the adhesive tape 122 is peeled off from the adhesive agent layer 22 of the stiffening plate laminate 20, as shown in Fig. 11.

Referring to Figs. 1, 2, 4 and 6, the stiffening plate 21 of the stiffening plate laminate 20 from which the release sheet 23 has been peeled off is placed above and aligned with the first camera 301 by means of the X-axis and Y-axis linear actuators 210 and 220. The first camera 301 takes an image of the stiffening plate 21 and inputs an image data thereof to the computer 303 (step S105) . By processing the image data of the stiffening plate 21 according to a pre-stored program, the computer 303 displays the image of the stiffening plate 21 on the monitor 304 and also calculates coordinate values of the stiffening plate 21 (step S106) .

Above the FPCB 10, the second camera 302 is moved in rectangular coordinates, by means of the X-axis linear actuator 210 and the Y-axis linear actuator 220. The second camera 302 takes an image of the FPCB 10 and inputs an image data thereof to the computer 303 (step S107) . By processing the image data of the FPCB 10 according to the pre-stored program, the computer 303 displays images of the contour lines 12 on the monitor 304 and also calculates coordinate values of the respective contour lines 12 (step S108). The computer 303 supplies the controller 310 with signals for controlling the robot 200 to ensure that the coordinate values of one of the contour lines 12 coincide with the coordinate values of the stiffening plate 21, namely to make sure that the image of one of the contour lines 12 displayed on the monitor 304 is matched with the image of the stiffening plate 21.

Referring to Figs. 1 and 2, the robot 200 is operated under the control of the controller 310 to attach the stiffening plate 21 onto the FPCB 10 in such a manner that the coordinate values of the stiffening plate 21 coincide with the coordinate values of the FPCB 10 (step S109) . Responsive to the signals inputted from the computer 303, the controller 310 operates the X-axis linear actuator 210, the Y-axis linear actuator 220 and the Z-axis rotary actuator 230 to thereby match the coordinate values of one of the contour lines 12 with the coordinate values of the stiffening plate 21. If the air cylinder 241 is operated to extend the cylinder rods 241b, the adhesive agent layer 22 is pressed against the upper surface of the FPCB 10 and, consequently, the stiffening plate 21 is attached to the upper surface of the FPCB 10 by the bonding force of the adhesive agent layer 22. At this time, the FPCB 10 is heated by the heater 116 as shown in Fig. 6, as a result of which the adhesive agent layer 22 of the stiffening plate 21 is melted to thereby firmly attach the stiffening plate 21 to the FPCB 10.

Finally, the second solenoid valve 253 is closed under the control of the controller 310 and then the stiffening plate 21 is dropped from the vacuum head 251. If the task of attaching the first stiffening plate 21 is completed in this way, the robot 200 is operated once again under the control of the controller 310, whereby the second stiffening plate laminate 20 received in another recess 31 of the tray 30 is moved, peeled off, aligned and attached to the FPCB 10 in the same manner as set forth above.

In Figs. 13 to 20, there is shown a stiffening plate attachment system in accordance with a second embodiment of the present invention. Referring to Figs. 13 to 16, the stiffening plate attachment system of the second embodiment includes a frame 100, a worktable 110, a release sheet peeling device 120, an image processing device 300, a first robot 400, a second robot 500 and a controller 600.

The frame 100, the worktable 110, the release sheet peeling device 120 and the image processing device 300 employed in the stiffening plate attachment system of the second embodiment are essentially of the same configuration as the corresponding elements of the first embodiment. Therefore, like parts are designated by the same reference numerals and no description will be given in the regard. The first robot 400 consists of an X-axis linear actuator 410, a Y-axis linear actuator 420, a Z-axis linear actuator 430 and a vacuum suction device 440. The X-axis linear actuator 410, the Y-axis linear actuator 420, the Z- axis linear actuator 430 and the vacuum suction device 440 of the first robot 400 are identical in basic construction to the corresponding parts of the robot 200 employed in the first embodiment. Therefore, no detailed description will be given on the operation of the first robot 400. Reference is made to the operation of the robot 200 employed in the first embodiment.

The Z-axis linear actuator 430 of the first robot 400 is mounted in such a way that it can be linearly reciprocated in a Y-axis direction by means of the Y-axis linear actuator 420. The first robot 400 operates to ensure that the stiffening plate laminate 20 received in one of the recesses 31 of the tray 30 is picked up by a vacuum head 441 of the vacuum suction device 440 and is bonded to the adhesive agent 123 of the adhesive tape 122. The vacuum head 441 is connected to the manifold 113 through a second air pipeline 442. A second solenoid valve 443 is provided on the second air pipeline 442 to control air flow. Although Figs. 17, 19 and 20 show that the vacuum head 441 of the first robot 400 is mounted to second and third hollow shafts 433 and 434 as is the case in the stiffening plate attachment system of the first embodiment, it may be possible to form the second and third hollow shafts 433 and 434 into a single hollow shaft.

The second robot 500 includes an X-axis linear actuator 510, a Y-axis linear actuator 520, a Z-axis rotary actuator 530, a Z-axis linear actuator 540 and a vacuum suction device 550, the basic construction of which is the same as that of the corresponding elements of the robot 200 employed in the first embodiment. Therefore, no detailed description will be given on the operation of the second robot 500. Reference is made to the operation of the robot 200 employed in the first embodiment. It can be seen in Figs. 19 and 20 that the second robot 500 has a vacuum head 551 mounted to second and third hollow shafts 533 and 534 as is the case in the stiffening plate attachment system of the first embodiment.

The second camera 302 of the image processing device 300 is mounted to the Y-axis linear actuator 520 of the second robot 500. The release sheet peeling device 120 has a roller 153 rotatably mounted to above the support table 150. The roller 153 serves to press the stiffening plate laminate 20 against the adhesive agent 123 of the adhesive tape 122 while the stiffening plate laminate 20 is moved together with the adhesive tape 122. Thus, the release sheet 23 of the stiffening plate laminate 20 is firmly attached to the adhesive agent 123 of the adhesive tape 122. As the moving direction of the adhesive tape 122 is turned at the first round portion 151 of the support table 150, the release sheet 23 is smoothly peeled off from the adhesive agent 123 of the adhesive tape 122. As illustrated in Figs 17 to 20, an elastic plate 154 is embedded in the top surface of the support table 150. The elastic plate 154 may be made of a material such as rubber, synthetic rubber, polyurethane or the like. The elastic plate 154 is adapted to support the stiffening plate laminate 20 in a position where the stiffening plate laminate 20 is picked up by the vacuum head 441 of the vacuum suction device 440 and is initially bonded to the adhesive agent 123 of the adhesive tape 122. It may be possible to apply the elastic plate 154 to the stiffening plate attachment system of the first embodiment.

On a downstream side of the support table 150, there is provided a standby table 170 for receiving the stiffening plate 21 fed from the support table 150. The support table 150 and the standby table 170 are spaced apart from each other at an interval 171 such that the adhesive tape 122 adhering to the release sheet 23 can pass with no interference. A wedge 172 is formed at a rear end of the standby table 170. The wedge 172 makes contact with a leading end of the release sheet 23 to ensure that the release sheet 23 is peeled off from the adhesive agent layer 22 of the stiffening plate laminate 20 fed from the support table 150 of the release sheet peeling device 120.

A guide plate 173 for guiding the stiffening plate 21 fed to the standby table 170 from the roller 153 is mounted between and above the support table 150 and the standby- table 170. The guide plate 173 serves to prevent the stiffening plate 21 from getting loose, when the release sheet 23 is peeled off, thereby accurately guiding the stiffening plate 21 to the top surface of the standby table 170. Alternatively, the guide plate 173 may be provided above the standby table 170.

The second robot 500 is operable to ensure that the stiffening plate 21 lying on the top surface of the standby table 170 is picked up by the vacuum head 551 of the vacuum suction device 550 and is attached to the FPCB 10. The vacuum head 551 is connected to the manifold 113 via the third air pipeline 552. A third solenoid valve 553 for controlling air flow is provided on the third air pipeline 552. Referring to Fig. 15, the controller 600 is adapted to control operations of the vacuum pump 114, the first solenoid valve 115, the heater 116, the servo motor 161 of the driving device 160, the first and second cameras 301 and 302 of the image processing device 300, the servo motors 412 and 422 of the X-axis and Y-axis linear actuators 410 and 420 of the first robot 400, the air cylinder 431, the second solenoid valve 443, the servo motors 512 and 522 of the X- axis and Y-axis linear actuators 510 and 520 of the second robot 500, the servo motor 532 of the Z-axis rotary actuator 530, the air cylinder 542 of the Z-axis linear actuator 540 and the third solenoid valve 553.

Hereinafter, description will be made with reference to Fig. 23 on a stiffening plate attachment method according to a second embodiment of the present invention, which is performed by the stiffening plate attachment system of the second embodiment set forth above. Steps S200 to S203 of the stiffening plate attachment method of the second embodiment are substantially the same as steps SlOO to S103 of the stiffening plate attachment method of the first embodiment. Furthermore, steps S206 to S211 of the stiffening plate attachment method of the second embodiment are substantially the same as steps S104 to S109 of the stiffening plate attachment method of the first embodiment. Therefore, no detailed description will be given on steps S200 to S203 and S206 to S211 of the stiffening plate attachment method of the second embodiment. Reference is made to steps SlOO to S109 of the stiffening plate attachment method of the first embodiment .

Referring first to Figs. 13 and 14, the FPCB 10 is prepared and placed on the worktable 110 (step S200) . The stiffening plate laminate 20 is prepared by positioning, on the upstream side of the support table 150, the tray 30 in which the stiffening plate laminate 20 is received so that the stiffening plate 21 can be faced upward (step S201) . Prepared next is the adhesive tape 122 coated with the adhesive agent 123 capable of adhering to and peeling off the release sheet 23 of the stiffening plate laminate 20

(step S202) . The release sheet 23 of the stiffening plate laminate 20 is bonded to the adhesive agent 123 of the adhesive tape 122 (step S203) .

Referring to Figs. 13 through 15, the vacuum head 441 of the vacuum suction device 440 is moved in rectangular coordinates by means of the X-axis and Y-axis linear actuators 410 and 420 of the first robot 400 and also moved up and down by means of the Z-axis linear actuator 430.

As shown in Figs. 17 and 18, the first robot 400 is operated so that the stiffening plate laminate 20 received in one of the recesses 31 of the tray 30 can be picked up by the vacuum head 441. As the first robot 400 continues to operate, the stiffening plate laminate 20 picked up by the vacuum head 441 is brought into alignment with the adhesive agent 123 of the adhesive tape 122 placed on the top surface of the support table 150. The vacuum head 441 is moved down by means of the Z-axis linear actuator 430 to press stiffening plate laminate 20 against the adhesive agent 123 of the adhesive tape 122. Once the lower surface of the release sheet 23 is bonded to the adhesive agent 123 of the adhesive tape 122, the suction pick-up of the vacuum head 441 is released. Due to the fact that the stiffening plate laminate 20 is produced by press-forming, e.g., blanking or punching, it is sometimes the case that the release sheet 23 is dislocated in a lateral direction and one lateral edge portion thereof is bonded to a side surface of the stiffening plate 21 or the adhesive agent layer 22, as can be seen in Fig. 21. In this case, the release sheet 23 may not be smoothly peeled off from the adhesive agent layer 22 of the stiffening plate laminate 20.

Referring to Fig. 22, the elastic plate 154 is elastically deformed by the pressing force of the vacuum head 441 and is adapted to support the stiffening plate laminate 20 when the stiffening plate laminate 20 is bonded to the adhesive agent 123 of the adhesive tape 122. Elastic deformation of the elastic plate 154 becomes smaller in the edge portion thereof than in the central portion to which an increased pressing force is applied by the vacuum head 441.

Even when the event that the edge portion of the release sheet 23 adheres to one side surface of the adhesive agent layer 22, the edge portion of the release sheet 23 is closely bonded to the adhesive agent 123 of the adhesive tape 122 because elastic deformation of the elastic plate 154 becomes smaller in the edge portion than in the central portion as noted above. Accordingly, in the subsequent release sheet peeling process, it is possible to smoothly peel off the release sheet 23 bonded to the adhesive agent 123 of the adhesive tape 122.

Once the release sheet 23 of the stiffening plate laminate 20 is bonded to the adhesive agent 123 of the adhesive tape 122, the stiffening plate laminate 20 and the adhesive tape 122 are moved together (step S204) , during which time the stiffening plate laminate 20 is pressed against and closely contacted with the adhesive tape 122

(step S205) . The release sheet 23 is peeled off from the stiffening plate laminate 20 while feeding the stiffening plate laminate 20 and the adhesive tape 122 in a closely contacted state (step S206) .

With a view to smoothly peel off the release sheet 23 of the stiffening plate laminate 20, it is possible to fix one of the stiffening plate laminate 20 and the adhesive tape 122 while allowing the other to move, after the release sheet 23 of the stiffening plate laminate 20 has been bonded to the adhesive agent 123 of the adhesive tape 122.

A first method of causing relative movement between the stiffening plate laminate 20 and the adhesive tape 122 is to allow the X-axis linear actuator 410 of the first robot 400 to displace the stiffening plate laminate 20 a specified distance, e.g., lcm, in an X-axis direction as illustrated in Fig. 17, after the release sheet 23 of the stiffening plate laminate 20 has been bonded to the adhesive agent 123 of the adhesive tape 122 by means of the vacuum head 441 of the first robot 400 and in a state that the stiffening plate laminate 20 remains picked up by the vacuum head 441.

A second method of causing relative movement between the stiffening plate laminate 20 and the adhesive tape 122 will be described with reference to Fig. 13. After the release sheet 23 of the stiffening plate laminate 20 has been bonded to the adhesive agent 123 of the adhesive tape 122 by means of the vacuum head 441 of the first robot 400, the vacuum head 441 is fixed in a state that the stiffening plate laminate 20 remains picked up by the vacuum head 441. Then, the adhesive tape 122 is supplied back from the reel 141 of the rewinder 140 and rewound on the reel 131 of the unwinder 130 to thereby move the adhesive tape 122 by, e.g., lcm, in a backward direction. In this case, the drive power of the servo motor 161 is transmitted to both the reel 131 of the unwinder 130 and the reel 141 of the rewinder 140 through the belt transmission mechanism 162 and another belt transmission mechanism, thereby simultaneously rotating the reels 131 and 141. According to the first and second methods of causing relative movement between the stiffening plate laminate 20 and the adhesive tape 122 as set forth above, the release sheet 23 adhering to the adhesive agent 123 of the adhesive tape 122 is smoothly peeled off from the adhesive agent layer 22 of the stiffening plate 21.

Referring to Figs. 13 and 14, the drive power of the servo motor 161 is transmitted to the reel 141 of the rewinder 140 through the belt transmission mechanism 162 as the servo motor 161 of the driving device 160 is driven. If the reel 141 of the rewinder 140 is rotated, the adhesive tape 122 is unwound from the adhesive tape roll 121 mounted to the reel 131 of the unwinder 130 and then wound on the reel 141 of the rewinder 140 after moving past the support table 150. As shown in Fig. 19, the stiffening plate laminate 20 moving together with the adhesive tape 122 is pressed by the roller 153 as it passes between the support table 150 and the roller 153. Thus, the release sheet 23 of the stiffening plate laminate 20 is firmly bonded to the adhesive agent 123 of the adhesive tape 122.

As can be seen in Fig. 20, the moving direction of the adhesive tape 122 is turned from a horizontal direction to a vertical direction at the first round portion 151 of the support table 150, whereby the release sheet 23 is smoothly peeled off from the adhesive agent layer 22 of the stiffening plate laminate 20. Thereafter, the adhesive tape 122 to which the release sheet 23 adheres is wound on the reel 141 of the rewinder 140. The guide plate 173 serves to prevent the stiffening plate 21 from getting loose, when the release sheet 23 is peeled off, thereby accurately guiding the stiffening plate 21 to the top surface of the standby table 170. The stiffening plate 21 is moved from the support table 150 to the standby table 170 where the stiffening plate 21 stands ready. Referring to Figs. 13, 14 and 20, the vacuum head 551 of the vacuum suction device 550 is moved in rectangular coordinates by means of the X-axis and Y-axis linear actuators 510 and 520 of the second robot 500 and also moved up and down by means of the Z-axis linear actuator 530. Furthermore, the Z-axis linear actuator 540 and the vacuum head 551 of the vacuum suction device 550 are rotated by means of the Z-axis rotary actuator 530.

In this way, the vacuum head 551 of the vacuum suction device 550 makes four-axis movement, i.e., linear reciprocating movement in X-axis, Y-axis and Z-axis directions and rotational movement about a Z-axis, which four-axis movement is caused by the X-axis, Y-axis and Z- axis linear actuators 510, 520 and 540 and the Z-axis rotary actuator 530. The stiffening plate 21 placed on the standby table is picked up by the vacuum head 551 of the vacuum suction device 550 and then brought into alignment with the first camera 301 of the image processing device 300.

The first camera 301 takes an image of the stiffening plate 21 and inputs an image data thereof to the computer 303 (step S207) . The computer 303 processes the image data of the stiffening plate 21 according to a pre-stored program and calculates coordinate values of the stiffening plate 21 (step S208) . The second camera 302 takes an image of the FPCB 10 and inputs an image data thereof to the computer 303 (step S209) . The computer 303 processes the image data of the FPCB 10 according to the pre-stored program and calculates coordinate values of each of the contour lines 12 (step S210) . The second robot 500 is operated to attach the stiffening plate 21 onto the FPCB 10 in such a manner that the coordinate values of the stiffening plate 21 coincide with the coordinate values of the FPCB 10 (step S211) . Using a pre-stored program, the computer 303 processes the image data of the stiffening plate 21 inputted from the first camera 301 and the image data of the FPCB 10 inputted from the second camera 302. The computer 303 controls the operation of the second robot 500 so that the coordinate values of the stiffening plate 21 is matched with the coordinate values of one of the contour lines 12. If the vacuum head 551 is moved down by means of the Z-axis linear actuator 540, the stiffening plate 21 is attached to the FPCB 10 by the bonding force of the adhesive agent layer 22. At this time, the FPCB 10 is heated by the heater 116, as a result of which the adhesive agent layer 22 of the stiffening plate 21 making contact with the FPCB 10 is melted to thereby firmly attach the stiffening plate 21 to the FPCB 10.

In the stiffening plate attachment system of the second embodiment, the stiffening plate laminate 20 is moved from the tray 30 to above the adhesive tape 122 by means of the first robot 400. Furthermore, the stiffening plate 21 from which the release sheet 23 has been peeled off is moved from the support table 150 to above the FPCB 10 by means of the second robot 500 and then the stiffening plate 21 is attached to the FPCB 10. This makes it possible for the second robot 500 to attach the stiffening plate 21, while the stiffening plate laminate 20 is transferred by means of the first robot 400. Accordingly, it is possible to reduce dead time and to increase the attachment speed of the stiffening plate 21, as compared to the stiffening plate attachment system of the first embodiment in which the stiffening plate laminate 20 is moved and attached by means of a single robot 200. Figs. 24 through 27 show a stiffening plate attachment system in accordance with a third embodiment of the present invention. The stiffening plate attachment system of the third embodiment is essentially of the same configuration as that of the second embodiment. Like parts are designated by the same reference numerals and no detailed description will be given in that regard.

Referring to Fig. 24, the stiffening plate attachment system of the third embodiment includes, among other things, the Z-axis linear actuator 430 of which the first robot 400 consists. The Z-axis linear actuator 430 has a central axis 445 inclined at a specified angle with respect to a vertical axis 446.

The inclined installation of the Z-axis linear actuator 430 ensures that, as illustrated in Fig. 25, a part of the lower surface of the release sheet 23 adjacent to the leading end of the stiffening plate laminate 20 is bonded to the adhesive agent 123 of the adhesive tape 122 but the remaining part of the lower surface of the release sheet 23 on the trailing end side of the stiffening plate laminate 20 is kept apart from the adhesive agent 123 of the adhesive tape 122. The elastic plate 154 is elastically deformed to support the stiffening plate laminate 20 adhering to the adhesive agent 123 of the adhesive tape 122.

If the adhesive tape 122 is moved in a state that the leading end of the release sheet 23 remains bonded to the adhesive agent 123 of the adhesive tape 122 in this way, the release sheet 23 is smoothly peeled off from the adhesive agent 123 of the adhesive tape 122. Owing to the fact that the stiffening plate laminate 20 is produced by press- forming, e.g., blanking or punching, the edge portion of the release sheet 23 is bonded to the adhesive agent layer 22 more firmly than the remaining portions thereof are. This means that, once the edge portion of the release sheet 23 is separated from the adhesive agent layer 22, the remaining portions are smoothly peeled off.

If the lower surface of the release sheet 23 is bonded to the adhesive agent 123 of the adhesive tape 122, the suction pick-up of the vacuum head 441 is released as can be seen in Fig. 26. The stiffening plate laminate 20 moving together with the adhesive tape 122 is pressed by the roller 153 as it passes between the support table 150 and the roller 153. Thus, the release sheet 23 of the stiffening plate laminate 20 is closely bonded to the adhesive agent 123 of the adhesive tape 122. It may be possible to eliminate the roller 153 in the stiffening plate attachment system of the third embodiment. The leading end of the release sheet 23 moving together with the adhesive tape 122 is brought into contact with the wedge 172 of the standby table 170 and is peeled off from the adhesive agent layer 22 of the stiffening plate 21. Referring to Fig. 27, the stiffening plate 21 from which the release sheet 23 has been peeled off is transferred from the support table 150 to the standby table 170, at which time the stiffening plate 21 is guided by means of the guide plate 173. The stiffening plate 21 standing ready on the top surface of the standby table 170 is picked up by the vacuum head 551 of the second robot 500 and is attached to the FPCB 10 in alignment with one of the contour lines 12 as illustrated in Fig. 14. The embodiments set forth hereinabove have been presented for illustrative purpose only and, therefore, the present invention is not limited to these embodiments. It will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention defined in the claims.

[Industrial Applicability]

As described above, the stiffening plate attachment system and method for use with a flexible printed circuit board in accordance with the present invention makes it possible to automate a series of stiffening plate processing steps including a peeling step, a moving step, an alignment step and an attachment step, thereby saving production costs and greatly improving productivity. Furthermore, the present system and method is capable of accurately attaching the stiffening plate to a surface of the flexible printed circuit board by processing images of the flexible printed circuit board and the stiffening plate acquired by first and second cameras. Moreover, the present system and method helps to prevent an adhesive agent coated on the stiffening plate from being contaminated by foreign materials.

Claims

[Claims]

1. A stiffening plate attachment system for use with a flexible printed circuit board, comprising: a worktable for supporting the flexible printed circuit board; a tray positioned on an upstream side of the worktable for receiving a stiffening plate laminate having a stiffening plate, an adhesive agent layer and a release sheet laminated one atop another; a release sheet peeling means provided between the worktable and the tray for moving an adhesive tape coated with an adhesive agent in such a way that the adhesive agent adheres to and peels off the release sheet of the stiffening plate laminate; and a robot provided between the worktable and the tray for picking up the stiffening plate laminate and moving the stiffening plate laminate from the tray to above the adhesive agent of the adhesive tape so that the release sheet can be bonded to and peeled off by the adhesive agent of the adhesive tape, the robot adapted to move the stiffening plate from the adhesive tape to above the flexible printed circuit board and to attach the stiffening plate to the flexible printed circuit board, the robot adapted to make linear reciprocating movement in X-axis, Y- axis and Z-axis directions and rotational movement about a Z-axis .

2. A stiffening plate attachment system for use with a flexible printed circuit board, comprising: a worktable for supporting the flexible printed circuit board; a tray positioned on an upstream side of the worktable for receiving a stiffening plate laminate having a stiffening plate, an adhesive agent layer and a release sheet laminated one atop another; a release sheet peeling means provided between the worktable and the tray for moving an adhesive tape coated with an adhesive agent in such a way that the adhesive agent adheres to and peels off the release sheet of the stiffening plate laminate; a standby table provided between the worktable and the release sheet peeling means for receiving the stiffening plate from the release sheet peeling means; a first robot provided between the tray and the release sheet peeling means for picking up the stiffening plate laminate and moving the stiffening plate laminate from the tray to above the adhesive agent of the adhesive tape so that the release sheet can be bonded to and peeled off by the adhesive agent of the adhesive tape, the first robot adapted to make linear reciprocating movement in X-axis, Y- axis and Z-axis directions; and a second robot provided between the worktable and the standby table for picking up the stiffening plate, moving the stiffening plate from the standby table to above the flexible printed circuit board and attaching the stiffening plate to the flexible printed circuit board, the second robot adapted to make linear reciprocating movement in the X-axis, Y-axis and Z-axis directions and rotational movement about a Z-axis.

3. The stiffening plate attachment system as recited in claim 1 or 2 , wherein a plurality of air suction holes is formed on a top surface of the worktable, the air suction holes connected to an air-sucking vacuum pump through an air pipeline, and wherein a heater for heating and melting the adhesive agent layer of the stiffening plate is provided within the worktable.

4. The stiffening plate attachment system as recited in claim 1, wherein the release sheet peeling means comprises: an unwinder mounted on the upstream side of the worktable, the unwinder having a reel on which the adhesive tape is wound; a rewinder provided between the worktable and the unwinder, the rewinder having a reel for winding the adhesive tape unwound from the reel of the unwinder; a support table provided between and above the unwinder and the rewinder for turning a moving direction of the adhesive tape toward the reel of the rewinder, the support table adapted to support the adhesive tape moving between the unwinder and the rewinder; and a driving means for providing drive power to rotate the reel of the rewinder.

5. The stiffening plate attachment system as recited in claim 2, wherein the release sheet peeling means comprises: an unwinder mounted on the upstream side of the worktable, the unwinder having a reel on which the adhesive tape is wound; a rewinder provided between the worktable and the unwinder, the rewinder having a reel for winding the adhesive tape unwound from the reel of the unwinder; a support table provided between and above the unwinder and the rewinder for turning a moving direction of the adhesive tape toward the reel of the rewinder, the support table adapted to support the adhesive tape moving between the unwinder and the rewinder; a driving means for providing drive power to rotate the reel of the rewinder; and a roller mounted above the support table for pressing the stiffening plate laminate adhering to the adhesive agent of the adhesive tape and moving together with the adhesive tape.

6. The stiffening plate attachment system as recited in claim 4 or 5, wherein an elastic plate is mounted on a top surface of the support table, the elastic plate adapted to support the stiffening plate laminate in a position where the stiffening plate laminate initially adheres to the adhesive agent of the adhesive tape.

7. The stiffening plate attachment system as recited in claim 5, wherein a wedge is provided at a rear end of the standby table, the wedge adapted to make contact with a leading end of the release sheet to peel off the release sheet from the adhesive agent layer of the stiffening plate laminate transferred from the release sheet peeling means.

8. The stiffening plate attachment system as recited in claim 5 or 7 , wherein a guide plate is mounted above the standby table, the guide plate adapted to guide the stiffening plate to a top surface of the standby table.

9. The stiffening plate attachment system as recited in claim 2, wherein the first robot includes a Z-axis linear actuator for making linear reciprocating movement in the Z- axis direction, the Z-axis linear actuator inclined to ensure that the release sheet adheres to the adhesive agent of the adhesive tape at a leading end of the stiffening plate laminate but remains spaced apart from the adhesive agent of the adhesive tape at a trailing end of the stiffening plate laminate.

10. The stiffening plate attachment system as recited in claim 2, further comprising: a first camera provided on a top surface of the worktable for acquiring an image of the stiffening plate and outputting an image data of the stiffening plate; a second camera mounted to the second robot for acquiring an image of the flexible printed circuit board placed on the worktable and outputting an image data of the flexible printed circuit board; and a computer for processing the image data of the stiffening plate inputted from the first camera and the image data of the flexible printed circuit board inputted from the second camera, the computer adapted to control an operation of the second robot so that the second robot can bring the stiffening plate into alignment with the flexible printed circuit board.

11. A stiffening plate attachment method for use with a flexible printed circuit board, comprising the steps of: preparing the flexible printed circuit board; preparing a stiffening plate laminate having a stiffening plate, an adhesive agent layer and a release sheet laminated one atop another; preparing an adhesive tape coated with an adhesive agent capable of adhering to and peeling off the release sheet of the stiffening plate laminate; causing the release sheet of the stiffening plate laminate to adhere to the adhesive agent of the adhesive tape; moving the stiffening plate laminate and the adhesive tape 122 in such a way that the release sheet is peeled off from the stiffening plate laminate; and attaching the stiffening plate to the flexible printed circuit board through the adhesive agent layer.

12. A stiffening plate attachment method for use with a flexible printed circuit board, comprising the steps of: preparing the flexible printed circuit board; preparing a stiffening plate laminate having a stiffening plate, an adhesive agent layer and a release sheet laminated one atop another; preparing an adhesive tape coated with an adhesive agent capable of adhering to and peeling off the release sheet of the stiffening plate laminate; causing the release sheet of the stiffening plate laminate to adhere to the adhesive agent of the adhesive tape; pressing the stiffening plate laminate against the adhesive tape while moving the stiffening plate laminate and the adhesive tape; peeling off the release sheet from the stiffening plate laminate while moving the stiffening plate laminate and the adhesive tape in a closely contacted state; and attaching the stiffening plate to the flexible printed circuit board through the adhesive agent layer.

13. The stiffening plate attachment method as recited in claim 11 or 12, wherein the step of peeling off the release sheet is performed by first moving the stiffening plate laminate and the adhesive tape in the same direction and then turning a moving direction of the adhesive tape.

14. The stiffening plate attachment method as recited in claim 11 or 12, wherein the step of attaching the stiffening plate to the flexible printed circuit board comprises the steps of: acquiring an image of the stiffening plate by use of a first camera to output an image data of the stiffening plate; processing the image data of the stiffening plate with a computer program to calculate coordinate values of the stiffening plate; acquiring an image of the flexible printed circuit board by use of a second camera to output an image data of the flexible printed circuit board; processing the image data of the flexible printed circuit board with the computer program to calculate coordinate values of the flexible printed circuit board required for attachment of the stiffening plate; and attaching the stiffening plate to the flexible printed circuit board through the adhesive agent layer in such a manner that the coordinate values of the stiffening plate coincide with the coordinate values of the flexible printed circuit board.

15. The stiffening plate attachment method as recited in claim 11 or 12, wherein heat is applied to melt the adhesive agent layer on the stiffening plate in the step of attaching the stiffening plate to the flexible printed circuit board.

16. The stiffening plate attachment method as recited in claim 12, wherein the step of causing the release sheet to adhere to the adhesive agent of the adhesive tape is performed to ensure that the release sheet adheres to the adhesive agent of the adhesive tape at a leading end of the stiffening plate laminate but remains spaced apart from the adhesive agent of the adhesive tape at a trailing end of the stiffening plate laminate.

17. The stiffening plate attachment method as recited in claim 12 or 16, wherein the step of causing the release sheet to adhere to the adhesive agent of the adhesive tape is performed by allowing the adhesive tape to be supported on an upper surface of an elastic plate and pressing the stiffening plate laminate against the adhesive agent of the adhesive tape supported on the upper surface of the elastic plate.

18. The stiffening plate attachment method as recited in claim 12 or 16, further comprising the step of: once the release sheet of the stiffening plate laminate adheres to the adhesive agent of the adhesive tape, fixing one of the adhesive tape and the stiffening plate laminate and moving the other so that the adhesive tape and the stiffening plate laminate can make relative movement to thereby peel off the release sheet from the adhesive agent layer of the stiffening plate.