Machine unit having retaining device using static electricity

Claim 2

In a machine unit having electrostatic holding means for retaining an object by electrostatic attraction force, said electrostatic holding unit including: a pair of electrodes; an attraction member in which static electricity is induced by said electrodes so as to generate an electrostatic attraction force which attracts and retains an object by said electrostatic attraction force; a power source circuit for supplying positive and negative charges to said pair of electrodes while changing the polarity thereof, said power source circuit including a DC power source having first and second terminals, electrically conductive means connected between said first and second terminals and said pair of electrodes, and switching means associated with said conductive means for selectively permitting said first and second terminals to be alternately and oppositely connected to said pair of electrodes in a predetermined time sequence for alternately reversing the electrical polarity of the electrodes; a support base; a conductive member interposed between said attraction member and said support base, said conductive member functioning as one of said electrodes; an insulative layer interposed between said conductive member and said support base; and said object comprising a semiconductor wafer functioning as the other of said electrodes.

Claim 3

In a machine unit having electrostatic holding means for retaining an object by electrostatic attraction force, said electrostatic holding unit including: a pair of electrodes; an attraction member in which static electricity is induced by said electrodes so as to generate an electrostatic attraction force which attracts and retains an object by said electrostatic attraction force; a power source circuit for supplying positive and negative charges to said pair of electrodes while changing the polarity thereof, said power source circuit including a DC power source having first and second terminals, electrically conductive means connected between said first and second terminals and said pair of electrodes, and switching means associated with said conductive means for selectively permitting said first and second terminals to be alternately and oppositely connected to said pair of electrodes in a predetermined time sequence for alternately reversing the electrical polarity of the electrodes; a rotatable roller having said attraction member extending around the peripheral surface thereof; and said electrodes being associated with said attraction member for enabling the object to be electrostatically attracted to the exposed surface of said attraction member.

Claim 4

In a machine unit having electrostatic holding means for retaining an object by electrostatic attraction force, said electrostatic holding unit including: a pair of electrodes; an attraction member in which static electricity is induced by said electrodes so as to generate an electrostatic attraction force which attracts and retains an object by said electrostatic attraction force; a power source circuit for supplying positive and negative charges to said pair of electrodes while changing the polarity thereof, said power source circuit including a DC power source having first and second terminals, electrically conductive means connected between said first and second terminals and said pair of electrodes, and switching means associated with said conductive means for selectively permitting said first and second terminals to be alternately and oppositely connected to said pair of electrodes in a predetermined time sequence for alternately reversing the electrical polarity of the electrodes; a rotatable roller having said attraction member extending around the peripheral surface thereof; and said electrodes being associated with said attraction member for enabling the object to be electrostatically attracted to the exposed surface of said attraction member.

Claim 5

A unit according to claim 2, wherein the electrodes of said pair are of a comblike configuration disposed in generally opposed and interfitting relationship, the electrodes having generally toothlike portions which project from the respective electrode in a direction generally toward the other electrode with said toothlike portions extending generally axially of said roller.

Claim 6

In a machine unit having electrostatic holding means for retaining an object by electrostatic attraction force, said electrostatic holding unit including: a pair of electrodes; an attraction member in which static electricity is induced by said electrodes so as to generate an electrostatic attraction force which attracts and retains an object by said electrostatic attraction force; a power source circuit for supplying positive and negative charges to said pair of electrodes while changing the polarity thereof, said power source circuit including a DC power source having first and second terminals, electrically conductive means connected between said first and second terminals and said pair of electrodes, and switching means associated with said conductive means for selectively permitting said first and second terminals to be alternately and oppositely connected to said pair of electrodes in a predetermined time sequence for alternately reversing the electrical polarity of the electrodes; a pair of spaced rotatable rollers having an endless conveyor belt supported on and extending between said pair of rollers; said attraction member defining the outer surface of said conveyor belt; and said pair of electrodes being mounted on said conveyor belt in association with said attraction member.

Claim 7

In a machine unit having electrostatic holding means for retaining an object by electrostatic attraction force, said electrostatic holding unit including: a pair of electrodes; an attraction member in which static electricity is induced by said electrodes so as to generate an electrostatic attraction force which attracts and retains an object by said electrostatic attraction force; a power source circuit for supplying positive and negative charges to said pair of electrodes while changing the polarity thereof, said power source circuit including a DC power source having first and second terminals, electrically conductive means connected between said first and second terminals and said pair of electrodes, and switching means associated with said conductive means for selectively permitting said first and second terminals to be alternately and oppositely connected to said pair of electrodes in a predetermined time sequence for alternately reversing the electrical polarity of the electrodes; a pair of spaced rotatable rollers having an endless conveyor belt supported on and extending between said pair of rollers; said attraction member defining the outer surface of said conveyor belt; and said pair of electrodes being mounted on said conveyor belt in association with said attraction member.

Claim 8

A unit according to claim 4, wherein the electrodes of said pair are of a comblike configuration disposed in generally opposed and interfitting relationship, the electrodes having generally toothlike portions which project from the respective electrode in a direction generally toward the other electrode with said toothlike portions extending generally transversely across said belt.

Claim 9

In a machine unit having electrostatic holding means for retaining an object by electrostatic attraction force, said electrostatic holding unit including: a pair of electrodes; an attraction member in which static electricity is induced by said electrodes so as to generate an electrostatic attraction force which attracts and retains an object by said electrostatic attraction force; a power source circuit for supplying positive and negative charges to said pair of electrodes while changing the polarity thereof, said power source circuit including a DC power source having first and second terminals, electrically conductive means connected between said first and second terminals and said pair of electrodes, and switching means associated with said conductive means for selectively permitting said first and second terminals to be alternately and oppositely connected to said pair of electrodes in a predetermined time sequence for alternately reversing the electrical polarity of the electrodes; a housing having an air inlet on one side thereof and an air outlet on the other side thereof, said housing defining a flow path therethrough from said air inlet to said air outlet; said electrostatic holding means being associated with said flow path for removing objects from the air flowing therethrough; said attraction member being a platelike member disposed within said path and oriented so as to extend generally in a direction parallel with said path; and said pair of electrodes being mounted on said platelike member.

Claim 10

In a machine unit having electrostatic holding means for retaining an object by electrostatic attraction force, said electrostatic holding unit including: a pair of electrodes; an attraction member in which static electricity is induced by said electrodes so as to generate an electrostatic attraction force which attracts and retains an object by said electrostatic attraction force; a power source circuit for supplying positive and negative charges to said pair of electrodes while changing the polarity thereof, said power source circuit including a DC power source having first and second terminals, electrically conductive means connected between said first and second terminals and said pair of electrodes, and switching means associated with said conductive means for selectively permitting said first and second terminals to be alternately and oppositely connected to said pair of electrodes in a predetermined time sequence for alternately reversing the electrical polarity of the electrodes; a housing having an air inlet on one side thereof and an air outlet on the other side thereof, said housing defining a flow path therethrough from said air inlet to said air outlet; said electrostatic holding means being associated with said flow path for removing objects from the air flowing therethrough; said attraction member being a platelike member disposed within said path and oriented so as to extend generally in a direction parallel with said path; and said pair of electrodes being mounted on said platelike member.

Claim 11

A unit according to claim 6, wherein one said electrode has a plurality of elongate electrode parts which extend generally parallel with one another in spaced relationship and are elongated generally perpendicularly with respect to the flow direction of said path, and wherein the other electrode of said pair has elongate electrode parts which are generally parallel with and interposed between the elongate electrode parts of said one electrode.

Claim 12

A unit according to claim 7, wherein the electrostatic holding means includes a plurality of said attraction members disposed in sidewardly spaced and generally parallel relationship so as to permit flow of air therebetween, each said attraction member having a pair of said electrodes associated therewith.

Claim 13

A unit according to claim 7, including a platelike support member of an insulating material disposed within said path and having a pair of said attraction members secured thereto on opposite sides thereof, each said attraction member having a pair of said electrodes associated therewith.