Patent Document

This is a continuation-in-part of application Ser. No. 08/824,389 filed, Feb. 26, 1997, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to manufacturing, and more specifically to microelectronics manufacturing. 
     BACKGROUND OF THE INVENTION 
     The fabrication of microelectronic devices such as semiconductor elements and LCD panels often involves various and repetitive processes. For example, an LCD panel is typically manufactured by submitting an LCD glass substrate to several processes including, but not limited to, a cleaning process for removing particles, a coating process for applying RGB resist and a developing process. Typically, each process is performed using equipment specific to a respective process. 
     A robot and the like are often configured to transport cassettes containing LCD glass substrates, as well as other semiconductor elements such as wafers, to and from the processing equipment. A robot is generally used when there are a series of programmed processes that need to be performed in a short period of time, typically without intervention. However in the event intervention is required, a robot may not be appropriate. For example, a robot is typically not used when randomly selected samples are conveyed to test equipment between the various processes for such purposes as determining whether the various equipment is functioning normally, or checking the quality of the LCD glass substrates. When unexpected errors occur in the process equipment, programmed process steps are typically unable to be successively performed. The occurrence of process equipment errors typically renders the use of robots inappropriate. 
     In cases where the use of a robot is inappropriate, cassettes are often conveyed by an operator via a Manual Guide Vehicle (MGV). Because cassettes containing samples often weigh between 50-60 kg, MGVs are advantageous for carrying these heavy cassettes. 
     A conventional MGV is shown in FIGS. 1 and 2 and is used for transporting LCD glass cassettes. In the illustrated embodiment, the MGV includes a body  17 , having a generally hexagonal shape. A load frame  2 , having a hexagonal shape, is positioned on top of the body  17 . The height of the load frame  2  is less than the height of the body  17 . The load frame  2  has a recessed part  29  on the top thereof. The recessed part  29  has an area that is larger than the area of the bottom of an LCD glass cassette  1 . The recessed part  29  has a predetermined depth configured to receive a cassette  1 . Formed in the center of the recessed part  29 , is an aperture  30 , which extends through the load frame  2  and forms an aperture  30   a  on the top of the body  17 . 
     A bar  9  extends through both apertures  30  and  30   a.  The bar  9  has generally the same diameter as the aperture  30 , and is configured to vertically reciprocate therein. The length of the bar  9  is approximately equal to the distance between the recessed part  29  and the bottom portion of the body  17 , as illustrated in FIGS. 1 and 2. 
     The upper end of the bar  9 , which extends through aperture  30   a  in the body  17  is connected to a support  3  and supports the LCD cassette  1 , as illustrated. The lower end of the bar  9  is in contact with the bottom portion of the body  17 , as illustrated. Only a portion of the bar  9  is supported within the apertures  30  and  30   a , as illustrated. Accordingly, a guide  11  is installed at a predetermined location in the body  17 , as illustrated. A guide aperture  12  is formed in the guide  11  for guiding the reciprocating movement of the bar  9  inserted therethrough. The guide aperture  12  has generally the same diameter as the bar  9 . 
     The lower part of the bar  9  includes a rack  8  containing teeth on a face thereof. The teeth of the rack  8  are configured to mesh with a pinion gear  7 , which is connected to a shaft extending from an electric motor  5 . Rotation of the pinion gear  7  via the electric motor  5  causes the bar  9  to vertically reciprocate. The pinion gear  7  includes a lock/unlock member (not shown) for suspending the movement of the bar  9  when the bar  9  is located at a predetermined position. 
     Still referring to FIGS. 1 and 2, the body  17  further includes a rechargeable battery  13  which is electrically connected to the input terminal of the electric motor  5  and to a charger  15  for charging the rechargeable battery  13  on demand. 
     The charger  15  is supplied with voltage from an external power supply through an electrical wire. One end of the wire is connected to the charger  15  and the other end is attached to a connector(not shown), which is inserted into an outlet of the external power supply. The charger  15  generally provides Direct Current (DC) output power to the electric motor  5 . 
     Typically, a control knob or a control panel  21  is installed on a handle  19  mounted on the body  17 , as illustrated. The power supplied to the motor  5  is adjusted by operating the control knob  21 . By adjusting the control knob  21  the motor  5  is selectively rotated in a positive/negative direction to thereby control reciprocation of the bar  9 . 
     Operation of a conventional MGV for transporting cassettes with LCD glasses will now be described. First, an operator operates the control knob  21  to unload LCD glass cassettes  1  from the MGV and load them into processing equipment for performing a respective process. Operation of the control knob  21  causes direct current electrical power to be output from the battery  13 , which has been charged by the charger  15  in advance, and supplied to the motor  5 . 
     When the motor  5  is supplied with electrical power, the motor  5  begins rotating in a predetermined direction together with the shaft connected thereto. The pinion gear  7  connected to the shaft rotates in the same direction as the shaft. The rotating motion of the pinion gear  7  is transmitted to the rack  8  at the lower portion of the bar  9 . The rack  8  translates the rotating motion of the pinion gear  7  into vertical reciprocating motion of the bar  9 . 
     The rack  8  continuously moves upwardly while the motor  5  is supplied with electrical power. When an LCD cassette  1  reaches a predetermined vertical position, the operator operates the control knob  21  to cause the motor  5  to stop rotating, thereby suspending the upward movement of the LCD cassette  1  via the bar  9 . The movement of the bar  9  is suspended via a ratchet which engages with the teeth of the pinion gear  7  to prevent the pinion gear  7  from further movement. The bar  9  then stops its upward movement and is not allowed to reverse its upward direction. When the LCD cassette  1  is at a predetermined height, it is either unloaded from the MGV to the processing equipment or loaded from the processing equipment to the MGV. 
     Referring to FIG. 3, another embodiment of a conventional MGV is illustrated. The illustrated MGV includes a charger  65  and a rechargeable battery  60  therein. The illustrated MGV includes a first motor  50  connected with vertical screws  40 , rather than a rack and pinion, to move the support  70 . A recessed portion  75  is formed in the support  70 . In the recessed portion is installed a second motor(not shown), which is operably engaged with horizontal screws  77  for horizontally moving an LCD cassette  80 . The second motor is electrically connected with the battery  60 . 
     Conventional MGVs, such as those described above with reference to FIGS. 1,  2  and  3  may have several disadvantages. One problem is the increased weight associated therewith. Because the MGVs have a heavy rechargeable battery as well as a charger for charging the battery therein, an operator can find the MGV to be somewhat difficult to pull or push. Another disadvantage is that the rechargeable battery often requires much time to be recharged. Another disadvantage is that an operator is often required to check the charging state of the battery in order to ensure proper operation. Typically, the battery cannot output enough power to move the support vertically if not properly charged. Hence, a smooth process may not result. Still another problem with conventional MGVs is that rechargeable batteries and chargers included therein, typically increase the cost of MGVs. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an MGV which can be of lighter weight than conventional MGVs and, thereby, is easier for an operator to pull and/or push. 
     It is another object of the present invention to eliminate the need for a rechargeable battery as a power supply. 
     To achieve the above and other objects of the invention, an MGV according to the present invention includes transporting means for transporting cassettes with samples to and from processing equipments, driving means for driving the transporting means, and power supplying means for supplying electrical power to the driving means. The power supplying means may include a power supplying device, installed on external equipment, for supplying an MGV with electrical power, and a power receiving device, installed in the MGV for receiving electrical power from the external equipment. The power supplying means may further include a first guide unit, installed on an MGV for guiding the power receiving device, and a second guide unit for limiting movement of the first guide unit. 
     An MGV configured according to the present invention is capable of receiving power for driving a cassette transporting device from external processing equipment instead of utilizing a rechargeable battery and charger system which are typically utilized in MGVs. A power receiving device having a connector portion is installed on the MGV, and a connector portion of a power supplying device is installed on the external processing equipment. The power receiving device includes a connector portion and guide pins. The connector portion includes pins configured to be inserted into the power supplying device in the external processing equipment. 
     An operator moves an MGV configured according to the present invention such that the power receiving device is aligned with the power supplying device in the processing equipment. Utilizing a foot lever, the operator engages the power receiving device with the power supplying device, thereby providing a continuous supply of electric power from the external processing equipment to the MGV. Operations for supplying power to an MGV for transporting cassettes to and from processing equipment, according to the present invention, therefore, include adjusting the power receiving device of an MGV to the power supplying device of external processing equipment, inserting a power receiving device into a power supplying device, and driving the driving means using power supplied therefrom. 
     An MGV configured according to the present invention is advantageous because it does not require a battery or a recharger. Accordingly, such an MGV is lighter in weight than MGVs with battery/recharger combinations. The lighter weight makes it easier for an operator to manipulate the MGV during microelectronic manufacturing operations. Furthermore, the MGV does not require time for charging of a battery. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic perspective view of a conventional MGV for transporting LCD cassettes with a portion cut away; 
     FIG. 2 is a schematic sectional of the MGV illustrated in FIG. 1; 
     FIG. 3 is a schematic perspective view showing the interior of another conventional MGV for transporting LCD cassettes; 
     FIG. 4 is a schematic perspective view of an embodiment of an MGV according to the present invention; 
     FIG. 5 is a schematic perspective view of another embodiment of an MGV according to the present invention; 
     FIG. 6 is a schematic perspective view of power receiving/supplying devices for an MGV according to the present invention; 
     FIG. 7 is a side view of a link/release device according to the present invention; 
     FIG. 8 is a front view of the link/release device illustrated in FIG.  7 . 
     FIG. 9 is a flowchart explaining a process for supplying electrical power to an MGV according to the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
     An embodiment of an MGV, according to the present invention, is illustrated in FIG.  4 . The MGV includes a conductive body  110  having a hexagonal shape. The body  110  has an opening  115  on a top portion thereof which is configured to receive a hexagonally-shaped support  120  for supporting an LCD cassette  150  thereon. The bottom portion of the support  120  has an area slightly smaller in size than that of the opening  115 , so that the support  120  can be inserted and positioned therewithin. The bottom of the support  120  is connected to two vertical screws  130  and  130   a  which allow the support  120  to move up and down. A first vertical screw  130  is connected to the shaft of a first motor  140 . A second vertical screw  130   a  is installed to prevent the support  120  from sloping to one side due to an eccentric load imposed on the side. 
     The first and second vertical screws  130  and  130   a  include a drive pulley  132  and a driven pulley  136 , respectively. A belt  134  is used to connect the pulleys  132  and  136  and to transmit the rotation energy of the motor  140  thereto. When the drive pulley  132  is rotated by the operation of the motor  140 , the driven pulley  136  rotates accordingly, thereby causing the support  120  to move up and down. 
     In the illustrated embodiment, the support  120  has a recessed portion  125 . Positioned within the recessed portion  125  are a pair of horizontal screws  127  for horizontally moving the LCD cassette  150 . The pair of horizontal screws  127  are engaged with a fixing unit  129  for fixing the cassette  150 . Preferably, a second motor(not shown) is connected with the pair of horizontal screws  127  such that, when the second motor rotates the pair of horizontal screws  127 , the fixing unit  129  moves back and forth horizontally. 
     As described above, the vertical movement of the support  120  is caused by the operation of the first motor  140 , while the horizontal movement of the support  120  is caused by the operation of the second motor. The first and second motors are supplied with electrical power from external processing equipment through a power receiving device  160 , which is installed on a side of the MGV. In the illustrated embodiment, the power receiving device  160  is located on the side of the MGV opposite from the side having the handle connected thereto. 
     The power receiving device  160  includes connector portion  162  and guide pins  164 . The connector portion  162  has a pair of pins for receiving direct current from the external equipment. The pair of pins are configured to be inserted into a connector portion in the external processing equipment, so that direct current is input through the pair of pins. The guide pins  164  are formed on both sides of the connector portion  162  and guide the connector portion  162  when the connector portion is inserted into the connector portion of the external equipment. The guide pins help prevent the connection of the two connector portions from becoming disengaged due to vibrations, and protects them from being damaged by external forces imposed on the connectors. Preferably, the specific resistance of the guide pins  164  is low. 
     The power receiving device  160  is connected to a power supply  166  as illustrated. The power supply  166  is a power transducer, and includes a transformer(not shown) and a rectifier(not shown). The transformer transforms alternating current electrical power from a first voltage to a lower second voltage of a predetermined effective value. The rectifier rectifies the lower voltage alternating current electrical power to direct current electrical power. 
     One of the output terminals of the power supply  166 , is electrically connected to the first motor  140  and to an input terminal of the second motor(not shown) via power cables. Another output terminal of the power supply  166  is connected to a motor driver  170  for driving the first and second motors, and to a control unit  180  for generating control signals to control the motor driver  170 . The control unit  180  is connected to a control panel or to a control knob  190 , and generates pulse signals corresponding to a function ordered by the operator. 
     Still referring to FIG. 4, at the bottom of the body  110  are four casters  105 , or wheels, which are free to swivel and which support the MGV. The casters  105  may be made of plastic-based materials or rubber-based materials having elastic characteristics. 
     Another embodiment of the MGV is illustrated in FIGS. 5 to  8 , wherein the power receiving device described above is installed on a side of the MGV. Except for the location of the power receiving device on the side of the MGV, all the other elements have similar locations on the MGV as described above and have basically the same functions as previously described. 
     Referring now to FIG. 6, the power receiving device installed on the side of the MGV will now be described in detail. The power supplying portion of the illustrated MGV includes: a power supplying device  240  configured to be installed on external LCD processing equipment; a power receiving device  210  configured to be installed on a side of the MGV; and a pressing unit  280  for pressing the power receiving device  210  to be inserted into the power supplying device  240 . 
     The power receiving device  210  includes: a first plate  212 , which is connected to the bottom of the MGV side as illustrated; a second plate  216  opposed to the first plate  212 ; four slide bars  214  attached to the first plate  212  and to the second plate  216  in a direction perpendicular to the two plates; and an electrode block  218  positioned between the two plates  212  and  216 . The four slide bars  214  pass through respective apertures in the electrode block  218  as illustrated. 
     The electrode block  218  is configured to move up and down along the slide bars  214 . When the electrode block  218  moves down, the power receiving device  210  may be electrically connected to a power supplying device  240 . When the electrode block  218  moves upwardly, the power receiving device  210  and power supplying devices are separated. A spring  219  may be positioned around each of the slide bars  214  between the first plate  212  and the electrode block  218 , or between the second plate  216  and the electrode block  218 . The springs act to push the electrode block  218  upwardly so as to separate the electrode block from the power supplying device  240 . 
     Still referring to FIG. 6, the electrode block  218  includes two electrode pins  218   a  and a guide pin  218   b  attached to the bottom thereof. The electrode pins  218   a  are preferably made of a conductive material and have a predetermined length. The guide pin  218   b  is preferably longer than the electrode pins  218   a  and guides the connection of the electrode pins  218   a  into the power supplying device  240 . 
     The guide pin  218   b  preferably is made of a material having a low electrical resistance. As a result, static electricity that may cause damage to the LCD glasses within the cassettes, may pass through the conductive body  210  of the MGV and through the guide pin  218   b.    
     In the illustrated embodiment, a guide roller  225  and locking roller  233  are connected to the MGV by respective brackets  220  and  230  installed on a bottom portion of the MGV. The guide and locking rollers  225  and  233  are preferably located on either side of the power receiving device  210  respectively, as illustrated. One bracket  230  preferably has a pin  236 , as illustrated, for double locking. The guide roller  225 , the locking roller  233  and the pin  236 , are collectively referred to as a first guide unit. When the MGV moves toward external processing equipment to receive electrical power, the first guide unit guides the MGV to facilitate inserting the power receiving device  210  into the power supplying device  240 . It will be apparent to those having skill in the art, that apertures  245  formed in the power supplying device  240  allow the pins  218   a  connected to the electrode block  218  of the power receiving device  210  to be inserted therewithin, as illustrated. 
     A guide block  250  is positioned adjacent the power supplying device  240  as illustrated. The guide block  250  includes a first roller cavity  255  for allowing the guide roller  225  to be inserted and locked therein. A locking block  260  is positioned adjacent the power supplying device  240  on a side opposite that of the guide block  250 . The locking block  260  includes a second roller cavity  266  for allowing the locking roller  233  to be inserted thereinto. When inserted into the second roller cavity  260 , the locking roller  233  locks the MGV with the external processing equipment. A pin cavity  263  for receiving the pin  236  allows for double locking. 
     A bar-type support  270  supporting the guide block  250  and the locking block  260  is provided as illustrated. The support  270 , the guide block  250  and the locking block  260  collectively form a second guide unit. FIG. 8 illustrates the guide block  250  and the locking block  260  in a complete locking state. 
     A pressing unit  280  is provided for pressing the electrode block  218  of the power receiving device  210  into the power supplying device  240 . The pressing unit  280  includes a press lever  284  and a foot lever  288  in a transverse relationship. One end of the press lever  284  is laid over the electrode block  218  and is configured to press the electrode block  218  into the power supplying device  240 . The opposite end of the pressing unit  280  is fixed at the bottom of the MGV with a bracket  282  attached thereto and a hinge by which the press lever  284  can pivot. A foot lever  288  is installed over the press lever  284  in a direction perpendicular to the press lever  284 . An end of the foot lever  288  is also fixed at the bottom of the MGV with a bracket  286  attached thereto and a hinge by which the foot lever  284  can also pivot. The opposite end of the foot lever  288  extends to the back side of the MGV, namely the side on which the handle(not shown) is installed, and extends outwardly from the bottom of the MGV. 
     When the foot lever  288  is pressed by the operator, the press lever  284  and the electrode block  218  are pressed downwardly. When the electrode block  218  is pressed by the press of the operator into the power supplying device  240 , power is supplied from the external processing equipment through the power supplying device and into the power receiving device  210 . In the illustrated embodiment, a lever bracket  288   a  is attached to the side of the MGV and is configured such that the foot lever  288  extends therethrough. The lever bracket  288   a  includes a locking lug  288   b  formed therein for maintaining the foot lever  288  in a “pressed-down” state. In operation, the foot lever is moved downwardly and into the locking lug  288   b.  When the foot lever  288  is maintained in the pressed-down state, power is continuously supplied from the external processing equipment to the MGV. 
     A common feature of the aforementioned embodiments of the present invention is that an MGV is structured to receive power for driving the first and the second motors therein from external processing equipment. Both embodiments include a power receiving device having a connector portion installed on the MGV, and a connector portion installed on the external processing equipment; and guide pins. The guide pins preferably have low resistance. 
     The guide pins are important in that they prevent the LCD glasses from shaking and from being damaged by static electricity generated in the MGV. Preferably, the LCD glass cassette to be loaded on the MGV is at least partially made of a conductive material to facilitate removing static electricity. 
     Cassettes for loading large scale LCD glasses generally includes LCD glass support (indicated as reference numeral  155  in FIG. 5) for supporting the glasses. The glass support  155  prevents the glasses from bending under their own weight. The LCD glass support is generally made of a conductive material. As a result, the static electricity in the glasses can be grounded by the LCD glass support as well as the guide pin. 
     Referring now to FIG. 9, a flowchart illustrates operations for supplying an MGV with power from external processing equipment. Initially, an operator moves an MGV toward external LCD processing equipment (Step S 1 ) so that LCD cassettes with LCD glasses therein can be processed. Next, the operator inserts the guide roller  225  of the first guide unit into the guide block  250  of the second guide unit to be locked. A determination is made whether the MGV is in the complete locking state (Step S 2 ). If only the guide roller  225  is inserted into the first roller cavity  255  of the guide block  250 , the locking state is incomplete. Therefore, the locking roller  233  and the locking pin  236  of the first guide unit are inserted into the second roller cavity  266  and the pin cavity  263  of the locking block  260  of the second guide unit, respectively. The MGV is then completely locked with the external equipment. 
     Once the MGV is in a complete locking state, the operator presses the foot lever  288  of the pressing unit  280 . Referring to FIG. 7, the position of the foot lever  288  is illustrated. The dashed line of the press lever  284  shows the foot lever  288  in the pressed-down position, while the solid line shows the foot lever  288  in the released position. When the foot lever  288  is pressed, the electrode block  218  of the power receiving device  210  of the MGV is pressed downwardly. As a result, the electrode pins  218   a  of the electrode block  218  are inserted into the holes  245  of the power supplying device  240  (Step S 3 ). 
     Once the power receiving device is connected to the power supplying device, the operator moves the foot lever  288  to the locking lug  288   b  of the lever bracket  288   a  in order to maintain a continuous supply of electric power. Electric power supplied from the equipment is passed through the power receiving device  210  and is converted to power capable of driving the first and second motor of the MGV. The converted power is sent to the first and the second motors in the MGV, the control unit  180 , and the motor driver  170 . Thereafter, the operator operates the control knob  190  or the control panel. 
     Responsive to the operation of the operator, the control knob generates signals, which are transmitted to the control unit  180 . The control unit  180  processes the signals and inputs the processed signals to the motor driver  170 . According to the signals from the control unit, the motor driver  170  generates signals for driving the first and the second motors. The first and the second drivers are operated by the signals from the motor driver  170 . The LCD glass cassettes are moved from the MGV to the equipment or from the equipment to the MGV by the operation of the motors (Step S 4 ). 
     As described above, the MGV according to the present invention is capable of receiving power for motors for driving a cassette transporting device from an external processing equipment instead of utilizing a rechargeable battery and charger system which are typically utilized in MGVs. The present invention is advantageous because an MGV configured according to the present invention may be lighter in weight and does not require time for charging of a battery. As a result MGV efficiency is enhanced. 
     The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. In the claims, means-plus-function clause are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.

Technology Category: 4