Patent Publication Number: US-2007102553-A1

Title: Apparatus and method of adjusting distinct carrier tape

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates generally to an apparatus of tape feeder, and more particularly to an apparatus or method which can fast adjusting a tape feeder to accommodate various carrier tapes of varying pitch, i.e., varying distance from one component to the next on the carrier tape.  
      2. Description of the Prior Art  
      After manufacturing, packaging and final testing, the Integrated Circuits (ICs) normally are packaged in a flexible carrier tape with pockets formed at regular intervals along its length, so that the ICs can be handled or picked-up easily. A tape and reel machine includes a plurality of tape feeder that can feed such carrier tapes. There are various types of ICs having different sizes, so that it is necessary to prepare many kinds of tape, and therefore it is necessary to adjust the tape feeder in accordance with various kinds of tape before advancing the tape.  FIG. 1  shows a front view of conventional adjusting distinct apparatus for adjusting a tape feeder. An image detector  11  (a charge coupled device, CCD, may be used) is installed above the carrier tape  12 , and it is employed for detecting the lack of pin or reverse orientation of the loaded ICs. Furthermore, a mid-hole detector  14  and a keyholes detector  15  are installed in the same side of the carrier tape near the image detector  11 .  
      Two adjacent pockets, mid-holes  13  and keyholes  16  are laid out in the schematic vertical view provided in  FIG. 2 . One mid-hole  13  was perforated in the bottom of each pocket, and the pitch A of the tape, defined as the distance between the center of the two adjacent mid-holes  13 . Pitches common in the industry are 8 mm, 12 mm, 16 mm and 20 mm. Perforated edge of the carrier tape includes keyholes  16 , which generally are 4 mm apart from each other, and the distance between mid-hole  13  and keyhole  16  is 2 mm.  
      A carrier tape  12  with different pitch A is necessary due to differences in the type of ICs. Some adjustment must be done while a different carrier tape  12  has been set in the tape feeder. The conventional adjustment apparatus part shown in  FIG. 1  includes three steps adjusting the tape feeder: (1) adjusting the position of the image detector  11 , made the center of the image detector  11  to aim at the center of one mid-hole  13 ; (2) tuning the position of mid-hole detector  14  to get another mid-hole  13  is sensed by it; (2) adjusting the position of the carrier tape  12  in its latitude direction so that the keyholes  16  can be detected by keyhole-detector  15 . The sequence of adjusting process is difficult, time consuming and tedious by using conventional tape feeder. In additional, the cost of the equipment and maintenance are much higher as too many detectors have been used in the conventional tape feeder.  
      Therefore, it would be an advantageous to have a novel apparatus and method that allow for fast adjusting the tape feeder, thereby speed up the adjustment, reduce the cost and increase the yield.  
     SUMMARY OF THE INVENTION  
      It is one object of the present invention to provide an apparatus for adjusting the tape feeder, thereby speed up the adjustment, reduce the cost and increase the yield.  
      According to the object, the present invention provides an adjusting distinct apparatus of tape feeder, which includes an image detector arranged above the tape, and a mid-detector for detecting the mid-hole of the carrier tape. The distance between the image detector and mid-hole detector is fixed at a constant as well as a common multiple of pitches of various tapes.  
      According to another embodiment, the present invention provides a method for adjusting distinct the tape feeder. Aiming the center of an image detector at the center of one mid-hole, then fixing a distance between the image detector and a mid-hole detector, and the distance is a multiple of pitches of various tapes, and the whole adjustment is finished while another mid-hole is detected by the mid-hole detector. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a front view of conventional adjusting apparatus of tape feeder.  
       FIG. 2  is a vertical plan view of the position of the mid-hole and the position of the keyhole.  
       FIG. 3  is a front view of adjusting distinct apparatus according to one embodiment of the present invention.  
       FIG. 4  is side view schematically illustrating the mechanism of fine adjustment (switch) according to one embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
      The detailed description of the present invention will be discussed in the following embodiments, which are not intended to limit the scope of the present invention, but can be adapted for other applications. While drawing are illustrated in details, it is appreciated that the quantity of the disclosed components may be greater or less than that disclosed, except expressly restricting the amount of the components.  
       FIG. 3  shows the fast adjusting distinct apparatus and method for a tape feeder according to one embodiment of the present invention. An image detector  31  is arranged above the carrier tape  32 , and its center is aimed at a line formed with a string of the centers of the mid-holes  33 , and it can only moves in direction of the longitude of the carrier tape  32 . The Charge Coupled Device (CCD) or other kinds of image detectors  31  such as Complementary Metal Oxide Semiconductor (CMOS) may be employed for adjusting the position and detecting the lack of the pin or reverse orientation of the loaded ICs.  
      A pair of mid-hole detectors  34  with a fixed distance apart from the image detector  31  is arranged above and under the carrier tape  32 . The center of the mid-hole detector  34  is aimed at a line formed with a string of the centers of the mid-holes  33 , and it can only moves in direction of the longitude of the carrier tape  32 . The mid-hole detector  34  consists of an emitter (such as infrared ray emitter) and a sensor, and it can be implemented in a number of ways in a preferred embodiment of the present invention. The emitter  34 , mid-hole  33  and sensor  34  are arranged in a row, the light (visible or invisible) emitted by emitter passes through the mid-hole  33 , and sensed by the sensor  34 . The circuit in interior of the mid-hole detector  34  will be actuated to the on state if the light was sensed by the sensor  34 ; and the circuit will stay on the off state if the light is not sensed by the sensor. Please note that the mid-hole detector  34  is arranged above and under the carrier tape  32  in this embodiment of the present invention, but both emitter and sensor could be arranged in the same side of the carrier tape  32  in others embodiments of the present invention. In such case the sensor will not sense the light because the light passes through the mid-hole, cause the off state; and the sensor will sense the light reflect off from IC or tape if one IC has been loaded, cause the on state.  
      There are various kinds of the carrier tapes, and pitches common in the industry are 8 mm, 12 mm, 16 mm and 20 mm. According to this embodiment of the present invention, take a common multiple of the 8, 12 and 20 and considering the space for easily operating, the distance between the image detector  31  and mid-hole detector  34  is fixed purposely at 360 mm. The carrier tape  32  with 16 mm pitch is to regard as a special case in this embodiment and will be explained later. The other distances may be chosen according to requirement of specific operating space, but must a common multiple of the 8, 12 and 20. If the major specification is no longer 8, 12 and 20 mm in the future, the distance shall be changed to another common multiple of the varying tape pitches, according to the same theory.  
      Because the distance between the image detector  31  and the mid-hole detector  34  is kept constant as well as it is a common multiple of 8, 12, and 20. Therefore, only one adjustment step is needed prior advancing the tape if one of the above tapes has set in the tape feeder, that is, adjusting the center of the image detector  31  to aim at the center of the mid-hole  33 , and the mid-hole detector  34  will also detect the mid-hole  33  simultaneously. As the image detector  31  and the mid-hole detector  34  can only move in the direction of the longitude of the tape, so that their center and the mid-holes is arranged on the same plane all the time, therefore there is no further latitude adjustment of the tape needed, and consequently the conventional keyholes detector  15  could be cancelled. The adjustment according to the present invention is faster, the cost is lower and the space needed is smaller than the conventional adjusting apparatus. Moreover, it is easy to adjust to the tape feeder when other tapes will be used according to the present invention. For example, set the parameter of the controller (comprise motor and its firmeware/software) in accordance with the specification of the carrier tape, adjust the image detector  31  to aim at one mid-hole  33 , and the mid-hole detector will also detect another mid-hole simultaneously, and all pre-setting before advancing the tape is finished.  
      According to the preferred embodiment hereinbefore, the distance between the image detector  31  and the mid-hole detector  34  depend on a common multiple of the 8 mm, 12 mm and 20 mm carrier tapes  32 ; however, the 16 mm carrier tape  32  not mentioned yet. Because 360 mm is not a multiple of 16 mm, therefore a further fine-tune mechanism  40  (also called a switch mechanism) is provided for handling the 16 mm pitch tape.  FIG. 4  schematically illustrate the side view of the fine-tune mechanism. Two V-cut are provided, which are 8 mm apart from each other in the depicted example; The distance 8 mm was evaluated by the formula: 360−352=8, where the 352 is a multiple of 16 (16×22=352) as well as the nearest number approaches the number 360. An anchoring ball  43  and a spring  42  coupling to the bottom of the mid-hole detector  34  are mounted between the mid-hole detector  34  and the fine-tune mechanism  40 , they are employed for moving and anchoring the mid-hole detector  34 . If the 16 mm carrier tape  32  has replaced, the adjustment process prior to advancement is change the position of the mid-hole detector  34  from one V-cut  41  to the other V-cut  41 , accordingly, the distance between the image detector  31  and the mid-hole detector  33  become 352 mm (360−8=352). The rest of the process need adjusting the tape feeder is the same as before, adjust the image detector to aim at the mid-hole, and the mid-hole detector  34  will also detect the mid-hole  33  simultaneously.  
      The V-cut  41 , spring  42  and anchoring ball  43  are employed in this embodiment of the present invention. However, other switch mechanism having different structure may be used in other embodiments according to the present invention as long as a constant distance will be kept between the two anchoring positions of the switch mechanism. Furthermore, the fine-tune mechanism  40  is installed under the mid-hole detector  34  in this embodiment, however, it will also practicable if the fine-tune mechanism is installed under the image detector  31 . In other words, the distance between the image detector and the mid-hole detector can be fine tuned by adjusting the position of the image detector  31  according to the same theory.  
      While the invention has been described in conjunction with a specific mode, it will be appreciated by those skilled in the art that various modifications, alternatives and variations may be made without departing from the scope of the present invention, which intended to be limited solely by the appended claims.