Patent Publication Number: US-2015083449-A1

Title: Contact apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application Serial No. 2013-196306, which was filed Sep. 23, 2013, and is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     Various embodiments generally relate to a contact apparatus configured to bring a movable member into contact with an object. 
     BACKGROUND 
     There is conventionally known a contact apparatus having a movable member and configured to bring the movable member (or another member attached to the movable member) into contact with an object. Patent document 1 discloses a bonding head used for a bonding apparatus, as one example of the contact apparatus as descried above. 
     The bonding head in Japanese Patent Application Laid-Open No. 2009-27105 has a bonding tool (or movable member) configured to suck and hold on a tip an electronic component such as a semiconductor chip, and to press the electronic component to a substrate (or object). As a pressure device of the bonding tool, there are two separate devices, i.e. a first pressure device configured to perform low load pressurization control and a second pressure device configured to perform high load pressurization control. The first pressure device can be moved by being disposed in a head moving device of the bonding head, while the second pressure device is a fixed device separated from the bonding head. The Patent document 1 describes that both high load pressurization (20 to 30 kgf) and low load pressurization (2 to 3 kgf) can be accurately performed thanks to this configuration. 
     By the way, for example, in a circumstance in which an extremely delicate component is handled, or in similar circumstances, it is desired in some cases that applied pressure between the movable member and the object is zero even though they are in contact with each other. In this regard, the bonding head in Japanese Patent Application Laid-Open No. 2009-27105 aims at pressurizing the electronic component with sufficient power to the substrate for the bonding, and the zero load as described above thus cannot be considered at all. 
     SUMMARY 
     In view of the aforementioned circumstances, various embodiments provide a contact apparatus which can realize the state in which the applied pressure is zero while the movable member (or another member attached to the movable member) and the object are in contact. 
     The problem to be solved by the present invention is as described above, and means for solving the problem and an effect thereof will be explained next. 
     According to various embodiments, a contact apparatus in the following configuration is provided. In other words, the contact apparatus is provided with: a contact head unit; and a control unit. The contact head unit is provided with: a movable member; a housing; a bearing gas passage; a thrust gas passage; and a cancel gas passage. The movable member may be in contact with an object. The housing forms a storage chamber for accommodating the movable member and supports the movable member linearly movably. The bearing gas passage is a passage for a compressed gas supplied to form a static pressure gas bearing between the housing and the movable member. The thrust gas passage is a passage for the compressed gas supplied to make a force act on the movable member, wherein the force is in a direction of bringing the movable member close to the object. The cancel gas passage is a passage for the compressed gas supplied to make a force act on the movable member, wherein the force is in a direction of putting the movable member away from the object. All of the bearing gas passage, the thrust gas passage, and the cancel gas passage are opened to the storage chamber of the housing. The control unit may set applied pressure of the movable member on the object to be zero by controlling at least any of pressure of the compressed gas supplied to the thrust gas passage and pressure of the compressed gas supplied to the cancel gas passage while the movable member is in contact with the object. 
     Incidentally, the expression “the movable member is in contact with the object” in the present disclosure includes not only a case where the movable member is in direct contact with the object, but also a case where a member attached to the movable member or a member held by the movable member is in contact with the object. 
     This configuration makes it possible to create the state in which the contact member (or the movable member) is in contact with the object at an applied pressure of zero, and a mechanical load applied to the object can be thus substantially eliminated. As a result, an appropriate contact state can be created even if the object is extremely delicate. 
     The contact apparatus described above preferably has the following configuration. The contact apparatus is provided with a setting unit configured to set the applied pressure of the movable member on the object in a predetermined range. Zero is included in the range of the applied pressure which can be set by the setting unit. 
     This makes it possible to set the applied pressure in a wide range including zero. It is thus possible to provide the contact apparatus which can be used in various applications. 
     The contact apparatus described above preferably has the following configuration. The contact apparatus is provided with a load sensor configured to detect a load of the movable member. The control unit controls at least any of the pressure of the compressed gas supplied to the thrust gas passage and the pressure of the compressed gas supplied to the cancel gas passage, on the basis of a detection value of the load sensor. 
     This allows feedback control while confirming the magnitude of the actual applied pressure. It is thus possible to easily realize a state in which the applied pressure is strictly zero. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the invention are described with reference to the following drawings, in which: 
         FIG. 1  is a conceptual diagram and a block diagram illustrating an entire configuration of a contact apparatus in an embodiment of the present disclosure; and 
         FIG. 2  is a conceptual diagram and a block diagram illustrating a modified example of the contact apparatus. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced. 
     Next, an embodiment of the present disclosure will be explained with reference to the drawings.  FIG. 1  is a conceptual diagram and a block diagram illustrating an entire configuration of a contact apparatus  1  in the embodiment of the present invention 
     The contact apparatus  1  illustrated in  FIG. 1  is an apparatus configured to bring a contact rod  21  into contact with an object  3 , for example, for the purpose of inspection or the like. The contact apparatus  1  is provided with a contact head unit  11  and a control unit  12 . 
     The contact head unit  11  is provided with the contact rod (or movable member, or needle, or contact member)  21  and a housing  22  configured to accommodate the contact rod  21  therein. The contact head unit  11  is configured as a static pressure air bearing actuator (or gas bearing actuator), and can support the contact rod  21  by an air bearing (or gas bearing) in a noncontact manner. The housing  22  is coupled via a coupling frame  23  which is a coupling member, to a not-illustrated driving apparatus which is provided with an electric motor, a feed screw mechanism, and the like. The driving apparatus can vertically displace the entire contact head unit  11 . 
     Inside the housing  22 , there is formed a rod storage chamber (or storage chamber)  24  configured to accommodate the contact rod  21  therein. The contact rod  21  is formed in a vertically long and narrow round-bar shape. An upper part of the contact rod  21  is inserted in the rod storage chamber  24 , and a lower part projects from the housing  22 . The contact rod  21  is supported with respect to the housing  22 , to be vertically displaced. By displacing the contact rod  21  downward in this configuration, the lower end of the contact rod  21  can be brought into contact with the object  3  set on the apparatus ( FIG. 1  illustrates the contact state). 
     In the rod storage chamber  24 , there is provided a cylindrical bush  25  formed of a porous material, and the bush  25  is disposed such that the contact rod  21  is inserted inside the bush  25 . Between the bush  25  and the contact rod  21 , there is formed a small gap in a radial direction. Moreover, a bearing air passage (or bearing gas passage)  31  is formed in the housing  22 . It is configured such that a compressed air (or compressed gas) supplied to the bearing air passage  31  passes through micropores formed in the bush  25 , which is formed of the porous material, and such that the compressed air uniformly jets into the gap between the bush  25  and the contact rod  21 . The contact rod  21  is held in the noncontact manner by the air bearing formed in this manner, and as a result, sliding resistance when the contact rod  21  vertically moves with respect to the housing  22  can be made small enough to be ignored. 
     One end of the bearing air passage  31  forms an opening in the rod storage chamber  24 , and the other end forms an opening (or bearing port  36 ) on an outer surface of the housing  22 . The bearing port  36  is connected to a compressed air source (or source of supply of a compressed air)  5 , through appropriate piping. 
     In the housing  22  of the contact head unit  11 , there is formed a thrust air passage (or thrust gas passage)  32 . One end of the thrust air passage  32  forms an opening in the rod storage chamber  24 , and the other end forms an opening (or thrust port  37 ) on the outer surface of the housing  22 . The thrust port  37  is connected to an electropneumatic regulator  42  configured to adjust the pressure of the compressed air supplied from the compressed air supply  5 , through appropriate piping. 
     Moreover, in the housing  22  of the contact head unit  11 , there is formed a cancel air passage (or cancel gas passage)  33 . One end of the cancel air passage  33  forms an opening in the rod storage chamber  24 , and the other end forms an opening (or cancel port  38 ) on the outer surface of the housing  22 . The cancel port  38  is connected to an electropneumatic regulator  43  configured to adjust the pressure of the compressed air supplied from the compressed air supply  5 , through appropriate piping. 
     This is not illustrated, but in the housing  22 , there is also formed an exhaust passage for letting out the compressed air supplied to the bearing air passage  31 , the thrust air passage  32 , and the cancel air passage  33 , as occasion demands. 
     Each of the two electropneumatic regulators  42  and  43  is electrically connected to the control unit  12  for controlling the operation of the contact apparatus  1 . The control unit  12  is configured as a microcomputer, and is provided with a central processing unit (CPU) as an arithmetic device, and a read only memory (ROM) and a random access memory (RAM) as a storage device, or the like, which are not illustrated. 
     The electropneumatic regulator  42  adjusts the pressure of the compressed air supplied to the thrust port  37  to pressure according to an electrical signal from the control unit  12 . In the same manner, the electropneumatic regulator  43  adjusts the pressure of the compressed air supplied to the cancel port  38  to pressure according to an electrical signal from the control unit  12 . This allows the contact rod  21  to linearly move in a direction of approaching/leaving the object  3 . Moreover, the details will be described later, but the applied pressure of the contact rod  21  on the object  3  can be changed by the control of the pressure. 
     The used two electropneumatic regulators  42  and  43  are high-resolution. By this, each of the pressure of the thrust port  37  and the pressure of the cancel port  38  can be fully controlled. 
     An operation panel (or setting unit)  45  for setting the operation of the contact apparatus  1  is electrically connected to the control unit  12 . The operation panel  45  is provided with an appropriate operating device (e.g. keys, a dial, a touch panel, etc.), and a user can set various parameters when operating the contact apparatus  1  by operating the operating device. The set parameters are stored in the storage device provided in the control unit  12 . 
     One of the parameters which can be set by the user with the operation panel  45  is the magnitude of the applied pressure of the contact rod  21  pressurizing the object  3 . In other words, by operating the operation panel  45 , the user can input and set the magnitude of a force with which the contract rod  21  is pressed to the object  3 , in a predetermined range. 
     On the contact apparatus  1  in the embodiment, zero is included in the range of the applied pressure which can be set by the user. A specific range of the applied pressure has, for example, a lower limit of 0 gf and an upper limit of 3 kgf. If 0 kgf is set as the applied pressure, the control unit  12  controls the two electropneumatic regulators  42  and  43  such that a force with which the contract rod  21  is pressed downward by the compressed air supplied to the thrust port  37 , the weight of the contact rod  21  and a force with which the contact rod  21  is pressed upward by the compressed air supplied to the cancel port  38  are in balance. 
     The contact rod  21  is configured by using a light material, and the sliding resistance is substantially zero due to the air bearing described above. The weight of the contact rod  21  can be cancelled by the supply of the compressed air to the cancel port  38 . Moreover, the applied pressure generated on the contact rod  21  is so-called differentially controlled by the pressure supplied to the thrust port  37  and the cancel port  38 , and the used electropneumatic regulators  42  and  43  for controlling the pressure are high-resolution. By this, the control unit  12  can realize a state in which the contact rod  21  is in contact with the object  3  but is substantially not pressed to the object  3 . 
     The state of the contact at an applied pressure of zero can be expressed as “extremely soft touch”, and can be used in various scenes which cannot be considered before. As one example, the configuration of the contact apparatus  1  in the embodiment is extremely useful in a case where the application of a mechanical load to the object  3  changes characteristics during characteristic inspection in which a probe or the like is in contact with the object  3 . The control apparatus  1  in the embodiment can also satisfy the needs of performing electrification inspection or conduction inspection on a component made of an extremely delicate material, without a problem. 
     As explained above, the contact apparatus  1  in the embodiment is provided with the contact head unit  11  and the control unit  12 . The contact head unit  11  is provided with the contact rod  21 , the housing  22 , the bearing air passage  31 , the thrust air passage  32 , and the cancel air passage  33 . The contact rod  21  can be in contact with the object  3 . The housing  22  forms the rod storage chamber  24  for accommodating the contact rod  21  therein and supports the contact rod  21  linearly movably. The bearing air passage  31  is a passage for the compressed air supplied to form the static pressure air bearing actuator between the housing  22  and the contact rod  21 . The thrust air passage  32  is a passage for the compressed air supplied to make a force act on the contact rod  21 , wherein the force is in a direction of bringing the contact rod  21  close to the object  3 . The cancel air passage  33  is a passage for the compressed air supplied to make a force act on the contact rod  21 , wherein the force is in a direction of putting the object rod  21  away from the object  3 . All of the bearing air passage  31 , the thrust air passage  32 , and the cancel air passage  33  are opened to the rod storage chamber  24  of the housing  22 . The control unit  12  can set the applied pressure on the object  3  to be zero by controlling the pressure of the compressed air supplied to the thrust air passage  32  and the pressure of the compressed air supplied to the cancel air passage  33  while the contact rod  21  is in contact with the object  3 . 
     This makes it possible to create the state in which the contact rod  21  is in contact with the object  3  at an applied pressure of zero, and the mechanical load applied to the object  3  can be thus substantially eliminated. As a result, an appropriate contact state can be created even if the object  3  is extremely delicate. 
     Moreover, the contact apparatus  1  in the embodiment is provided with the operation panel  45  configured to set the applied pressure of the contact rod  21  on the object  3  in the predetermined range. The range of the applied pressure which can be set with the operation panel  45  includes zero. 
     This makes it possible to set the applied pressure in a wide range including zero. It is thus possible to provide the contact apparatus  1  which can be used in various applications. 
     Next, a modified example of the embodiment will be explained.  FIG. 2  is a conceptual diagram and a block diagram illustrating a contact apparatus  1   x  in the modified example. In the explanation of the modified example, the same members as or similar members to those of the aforementioned embodiment will carry the same reference numerals in the drawing, and the explanation will be omitted in some cases. 
     In the contact apparatus lx in the modified example, an upper end of the contact rod  21  projects from the housing  22 , and a load cell  46  as a load sensor is attached to a tip of the upper end. A piece  47  to be detected is fixed in an upper part of the housing  22 , and the load cell  46  is in contact with the piece  47  to be detected. The load cell  46  is electrically connected to the control unit  12 . 
     In the above configuration, the control unit  12  controls the pressure supplied to the thrust port  37  and the cancel port  38 , on the basis of the magnitude of a load detected by the load cell  46 . This realizes fully-closed feedback control, and it is thus possible to realize the state in which the applied pressure is zero, more accurately. 
     As exemplified above, the control apparatus  1  in the modified example is provided with the load cell  46  configured to detect the load of the contact rod  21 . The control unit  12  controls the pressure of the compressed air supplied to the thrust air passage  32  and the pressure of the compressed air supplied to the cancel air passage  33 , on the basis of a detection value of the load cell  46 . 
     This allows the feedback control of the pressure while actually confirming the magnitude of the applied pressure of the contact rod  21 . It is thus possible to easily realize the state in which the applied pressure is strictly zero. 
     The preferred embodiment and the modified example of the present invention are explained above; however, the aforementioned configuration can be changed, for example, as follows. 
     Instead of the aforementioned embodiment in which the contact rod  21  is brought into contact with the object  3 , it may be configured such that another member such as, for example, an inspection probe is fixed to or another component is held by the contact rod  21 , and the member/component is brought into contact with the object  3 . 
     In the aforementioned embodiment, in order to realize the applied pressure of zero, the control unit  12  controls both the pressure of the thrust air passage  32  and the pressure of the cancel air passage  33 . Instead of this, however, one of the pressures may be kept constant and only the other pressure may be controlled, to realize the applied pressure of zero. 
     The configuration of the contact head unit  11  is not limited to the aforementioned example. For example, not a simple member but a combination of a plurality of members may be used to form the contact rod and the housing. Moreover, as a pressure medium of the actuator, a gas other than the air may be also used. 
     While the disclosure has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims. The scope of the disclosure is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced. 
     DESCRIPTION OF REFERENCE NUMERALS AND LETTERS 
       1  contact apparatus 
       3  object 
       5  compressed air source 
       11  contact head unit 
       12  control unit 
       21  contact rod (or movable member) 
       22  housing 
       31  bearing air passage (or bearing gas passage) 
       32  thrust air passage (or thrust gas passage) 
       33  cancel air passage (or cancel gas passage) 
       42  electropneumatic regulator 
       43  electropneumatic regulator 
       45  operation panel (or setting unit) 
       46  load cell (or load sensor)