Patent Publication Number: US-8523510-B2

Title: Method for moving and securing a substrate

Description:
TECHNICAL FIELD 
     The invention relates generally to moving and securing a substrate and, more particularly, to a system for moving and securing a flexible substrate for the purpose of coating the substrate with a desired coating. 
     BACKGROUND 
     The use of Thin Film Transistor (TFT) displays have become commonplace over the years. In fact, TFT displays have become so ubiquitous that there is an ever-increasing desire to implement these displays in more devices. Typically, TFT displays are “built on” a flexible plastic substrate. These flexible substrates, though, are difficult to handle in comparison to the glass substrates of their Flat Panel Display (FPD) counterparts. With the glass of the FPDs, it is relatively easy to maneuver the glass because of its rigidity, but the substrates of the TFT displays tend to bend and move very easily under the influence of gravity, causing limited maneuverability. Some examples of devices that address maneuvering substrates are U.S. Pat. Nos. 5,352,294; 5,611,865; 7,055,535; and 7,137,309. Therefore, there is a need for an apparatus and/or system to move flexible substrates. 
     SUMMARY 
     A preferred embodiment of the present invention, accordingly, provides an apparatus for transferring and securing a substrate. A pressure source is provided that is adapted to provide positive and negative pressure. A vacuum chuck is provided having a top side with a plurality of vacuum chuck portals formed therein. Each vacuum chuck portal is in fluid communication with the pressure source. The substrate is secured to the top side of the vacuum chuck when the pressure source provides negative pressure to the vacuum chuck portals. An intermediate member that selectively cooperates with the vacuum chuck to support and transfer the substrate between the vacuum chuck and the intermediate member is provided. The intermediate member has a plurality of receiving spaces and a plurality of transfer members. The receiving spaces and transfer members are adjacent to one another in an alternating pattern, and each transfer member has a top side with a plurality of transfer member portals formed therein. Each transfer member portal is in fluid communication with the pressure source. A carriage extending along at least a portion of the periphery of the vacuum chuck and along at least a portion of the periphery of the intermediate member is provided. The carriage engages at least a portion of the substrate when the pressure source provides positive pressure to the vacuum chuck portals and transfer member portals to transfer the substrate between the intermediate member and the vacuum chuck. 
     In accordance with a preferred embodiment of the present invention, the pressure source further comprises a manifold that is in fluid communication with the vacuum chuck portals and transfer member portals, a vacuum pump in selective fluid communication with the manifold, and a positive pressure pump that is in selective fluid communication with the manifold. 
     In accordance with another preferred embodiment of the present invention, the intermediate member and the vacuum chuck are each generally rectangular. 
     In accordance with a preferred embodiment of the present invention, the carriage extends along at least a portion of a pair of opposing sides of each of the intermediate member and the vacuum chuck. 
     In accordance with a preferred embodiment of the present invention, the top sides of the transfer members and the vacuum chuck have an anti-static coating. 
     In accordance with a preferred embodiment of the present invention, the apparatus further comprises a gas ionizer located in a position above the top sides of the transfer members and the vacuum chuck. 
     In accordance with a preferred embodiment of the present invention, an apparatus for moving and securing a substrate is provided. A pressure source that is adapted to provide positive and negative pressure is provided. An end effector adapted to move the substrate from a first position is provided. The end effector has a base with a plurality of spaced apart tines extending thereform and a top side with a plurality of end effector portals formed therein. Each end effector portal is in fluid communication with the pressure source. A vacuum chuck is provided having a top side with a plurality of vacuum chuck portals formed therein. Each vacuum chuck portal is in fluid communication with the pressure source. The substrate is secured to the top side of the vacuum chuck when the pressure source provides negative pressure to the vacuum chuck portals. An intermediate member that selectively cooperates with the vacuum chuck to support and transfer the substrate between the vacuum chuck and the intermediate member is provided. The intermediate member has a plurality of receiving spaces and a plurality of transfer members. Each receiving space is adapted to receive at least one tine, and each transfer member is adjacent to at least one tine when the end effector engages the intermediate member. Each transfer member has a top side with a plurality of transfer member portals formed therein that are each in fluid communication with the pressure source. A carriage extending along at least a portion of the periphery of the vacuum chuck and along at least a portion of the periphery of the intermediate member is provided. The carriage engages at least a portion of the substrate when the pressure source provides positive pressure to the vacuum chuck portals and transfer member portals to transfer the substrate between the intermediate member and the vacuum chuck. 
     In accordance with a preferred embodiment of the present invention, an apparatus for moving and securing a substrate is provided. A pressure source that is adapted to provide positive and negative pressure is provided. An end effector is provided having a base with a plurality of spaced apart tines extending thereform. The end effector has a top side with a plurality of end effector portals formed therein, and each end effector portal is in fluid communication with the pressure source. A generally rectangular vacuum chuck is provided having a top side with a plurality of vacuum chuck portals formed therein. Each vacuum chuck portal is in fluid communication with the pressure source. A generally rectangular intermediate member that selectively cooperates with the vacuum chuck to support and transfer the substrate between the vacuum chuck and the intermediate member is provided. The intermediate member has a plurality of receiving spaces and a plurality of transfer members. Each receiving space is adapted to receive at least one tine, and each transfer member is adjacent to at least one tine when the end effector engages the intermediate member. Each transfer member has a top side with a plurality of transfer member portals formed therein that are each in fluid communication with the pressure source, and the top sides of the vacuum chuck and the transfer members are generally coplanar. A mechanical arm is secured to the end effector that is adapted to move the end effector from a first position of the substrate to the intermediate member. A carriage extending along at least a portion of a pair of opposing sides of each of the intermediate member and the vacuum chuck is provided. The carriage engages at least a portion of the substrate when the pressure source provides positive pressure to the vacuum chuck portals and transfer member portals to move the substrate between the intermediate member and the vacuum chuck. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a diagram depicting the substrate transfer system in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is an isometric view of the chuck assembly, mechanical arm, end effector, and gas ionizer in accordance with a preferred embodiment of the present invention; 
         FIG. 3  is a top view of the chuck assembly in accordance with a preferred embodiment of the present invention; 
         FIG. 4  is a bottom view of the chuck assembly in accordance with a preferred embodiment of the present invention; 
         FIG. 5  is a side elevation view of the chuck assembly in accordance with a preferred embodiment of the present invention; 
         FIG. 6  is a rear elevation view of the chuck assembly in accordance with a preferred embodiment of the present invention; and 
         FIG. 7  is a front elevation view of the chuck assembly in accordance with a preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Refer now to the drawings wherein depicted elements are, for the sake of clarity, not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views. 
     Referring to  FIG. 1 , a system  100  for transferring a flexible substrate  112  is shown. Typically, systems, like system  100 , are factory or automation systems employed to maneuver or transfer a substrate  112 , like sheets of polyethylene terephthalate (PET) used in the production process for the manufacturing of TFT displays, from a first position at one location to a second position at a second location. Here, as an example, the system  100  comprises storage  102  where the substrate  112  can be held in a first position so that the substrates can be moved or transferred to a second position at chuck assembly  300 . Preferably, movement between the first and second positions is accomplished through the use of a multi-axis mechanical arm  104  and an end effector  200  that is secured to the mechanical arm  104 . The preferred multi-axis mechanical arm  104  is an articulated robot. 
     Typically, these substrates  112  are very light (weighing on the order of a few grams) and subject to displacement by air currents and slight movements. Additionally, these substrates are usually very delicate and can be easily damaged. 
     So, positive and negative air pressures are employed in system  100  to assist in facilitating the movement of and securing of the substrate  112 . Providing the positive and negative air pressures is a pressure system (not labeled) that comprises a vacuum pump  108  and a positive pressure pump  110  that are each in fluid communication with a manifold  106  as well as other pumps, valves, and manifolds. Preferably, the pressure system (not labeled) employs the manifold  106  to control pressure delivery from the vacuum pump  108  and positive pressure pump  110 , generally through the use of one or more valves (not shown). Additionally, as can be seen in  FIG. 2 , an example of a manifold  106  is shown. The manifold  106  is secured to nipples  318  along the edge of the chuck assembly  300  so that positive and negative pressures can be propagated to different portions of the chuck assembly (namely, the vacuum chuck portals  306  and the intermediate member portals  316  which are discussed in detail below). 
     Now turning to  FIGS. 2-7 , when substrates  112  are transferred, there typically is an interaction between the end effector  200  and the chuck assembly  300 . As shown, the chuck assembly  300  can be divided into several parts comprising the vacuum  302 , the intermediate member  308 , and the carriage  400 . When a substrate  112  is being transferred, there is an interaction between the end effector  200  and the intermediate member  308 . 
     As shown, the end effector  200  is secured to and maneuvered by the mechanical arm  104 . The end effector  200  is analogous to a fork and is comprised of a base member  202  and a plurality of tines  204 . The tines  204  typically extend generally perpendicular from the base  202  and are, preferably, spaced apart from one another by about 115 mm. The base  202  and tines  204  each have a top side  208  that can be coated with an anti-static coating, like NEDOX. The base  202  is generally rectangular, being about 350 mm×150 mm×6 mm, and the tines  204  are generally rectangular, being about 40 mm×500 mm×6 mm. Formed in the top surface of the base  202  and tines  204  (or end effector  200 ) are a plurality of end effector portals  206 . These portals  206  are in fluid communication with the pressure system (not labeled) so that positive and negative pressure can be applied to the substrate  112  when carried by the end effector  200 . Preferably, four tines  204  extend from the base  202 . 
     The intermediate member  308  has a geometry that is generally complementary to that of the end effector  200 . The intermediate member  308  is comprised of a plurality of receiving spaces  312  and transfer members  310  arranged in an alternating pattern. Each of the receiving spaces  312  is generally dimensioned and adapted to receive one of the tines  204 , measuring about 45 mm×495 mm×20 mm. Each of the transfer members  310  measures about 70 mm×495 mm×25 mm and includes a top side  314 . Preferably, the top side  314  is coated with an anti-static coating, such as NEDOX, and has a plurality of intermediate member portals  316  formed therein that are in fluid communication with the pressure system (not labeled). Preferably, there are three transfer members  310  and four receiving spaces  312 . 
     During operation, the mechanical arm  104  moves the end effector  200  to a first position where the substrate  112  is located, such as in storage  102 . The end effector is placed beneath the substrates  112 , and negative pressure (vacuum) is applied through the pressure system (not labeled) to the end effector portals  206 , securing the substrate  112  to the top side  208  of the end effector  200 . Once the substrate  112  is secured to the end effector  200 , the mechanical arm  104  moves the end effector  200  so as to engage the intermediate member  308 . When the end effector  200  engages the intermediate member  308 , the tines  204  are received in the receiving spaces  312  so that the top side  208  of the end effector  200  and the top side  314  of the intermediate member  308  are generally flush and/or coplanar and cooperate with one another to support the substrate  112 . Once the end effector  200  engages the intermediate member  308 , positive pressure can be applied to the intermediate member portals  316  and the end effector portals  206  to provide an air cushion to further manipulate or transfer the position of the substrate  112 . Additionally, the process can be reversed to remove the substrate  112  from the chuck assembly  300  and transfer it to another position. 
     Cooperating with the intermediate member  308  is the vacuum chuck  302 . The vacuum chuck  302  is generally rectangular, measuring about 400 mm×500 mm×50 mm, and is located adjacent to the intermediate member  308 . The vacuum chuck  302  also includes a top side  304 , which can be coated with an anti-static coating, such as NEDOX, and which is generally coplanar with the top side  314  of the intermediate member  308 . The top side  304  also includes a plurality of vacuum chuck portals  306  formed therein that are in fluid communication with the pressure system (not labeled). 
     Additionally, a carriage  400  can be employed to assist in the transferring of a substrate  112  between the vacuum chuck  302  and the intermediate member  308 . Preferably, the carriage  400  is located on and extends along at least a portion of the periphery of two opposing edges of the intermediate member  308  and the vacuum chuck  302 . In particular, the carriage  400  comprises a transfer assembly  402  and a linear drive (motor  404  and linear bearing stage  406 ). The transfer assembly  402  can move vertically (normal to the top sides  304  and  314 ) so as to engage a substrate  112  along its periphery (preferably at a corner), and the motor  404  can actuate the linear bearing stage  406 , which moves the transfer assembly  402  horizontally. 
     In moving horizontally, the transfer assembly  402  engages a pair of cable/tubing management tracks  408 . The tracks  408  are, preferably, suspended from the underside or bottom of the chuck assembly  300 . Therefore, the tracks  408  provide both guidance and support for the cables and tubing connected to the transfer assembly  402 . 
     Thus, during operation and once the end effector  200  has engaged the intermediate member  308 , positive pressure is applied to the end effector portals  206 , the intermediate member portals  316 , and vacuum chuck portals  306  thereby forming an aircushion for the substrate  112  to “float on.” The transfer assembly  402  moves vertically so as to engage the substrate  112 . Once engaged, the motor  404  actuates the linear bearing stage  406  to transfer the substrate  112  from the intermediate member  308  to the vacuum chuck  302 . Once transferred, negative pressure can be applied to the vacuum chuck portals  306  to cause the substrate  112  to be secured to the vacuum chuck  302  so as to allow for further processing of the substrate to take place. Additionally, the process can be reversed to remove the substrate  112  from the chuck assembly  300  and transfer it to another position. 
     Because of the volume of air moving around the substrate  112 , it is possible for the gas to become ionized, which can materially alter the properties of the substrate  112  and affect further processing of the substrate. To help combat this gas ionization, a de-ionizer  114 , such as MKS Ion Systems AeroBar VF Model 5359, can be positioned above the chuck assembly  300 . 
     Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered obvious and desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.