SELF-CLEANING ADHESIVE STRUCTURE AND METHODS
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Abstract
A method and apparatus for transporting an object from one workstation to another, or for manipulating an object within a workstation, where the object or workstations may be contaminated with unwanted dirt or dust particles, are disclosed. The object is gripped at one work station with a movable transfer arm a movable transfer arm having an end effector composed of an array of nano-scale projections, where each projection provides one or more distal contact ends, the density of contact ends is such as to grip a surface of the object with an intermolecular force sufficient to hold the object for movement, where the relative sizes of the object and particles are such that the object makes contact with severalfold times of the number of contact ends than contacted by such particles. After moving the gripped object to the other workstation, the end effector is manipulated to release the gripped object at the other workstation. Before, during or after transport of the object, the arm'"'"'s end effector is brought into contact with a cleaning surface having a surface energy interaction with particles carried on said effector as great or greater than the surface energy interaction between particles and effector, thereby to transfer such particles to the cleaning surface. Also disclosed is an apparatus for transporting small elements or objects in a nano- or micro-fabrication assembly or in printing, and a self-cleaning adhesive tape.
17 Citations
21 Claims
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1-6. -6. (canceled)
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7. Apparatus for transporting an object from one workstation to another, or for manipulating an object within a workstation, where the object or workstations may be contaminated with unwanted dirt or dust particles, said apparatus comprising:
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(a) a movable transfer arm having an end effector composed of an array of nano-scale projections, where each projection provides one or more distal contact ends, the density of contact ends is such as to grip a surface of the object with an intermolecular force sufficient to hold the object for movement, and the relative sizes of the object and particles are such that the object makes contact with severalfold times of the number of contact ends than contacts such particles, (b) a cleaning surface disposed within the area of movement of the transfer arm, said surface having a surface energy interaction with particles carried on said end effector as great or greater than the surface energy interaction between particles and effector, and (c) a control unit operatively connected to said arm and configured to; (i) place said end effector in contact with such an object at one workstation thereby to grip the object, (ii) move the arm and gripped object within the workstation or to another workstation; (iii) manipulate said end effector to release the gripped object, and (iv) bring said end effector into contact with the cleaning surface one or more times, to transfer unwanted dust particles on the gripping surface to the cleaning surface. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
spatular stalk terminating at a distal contact ends, and said spatulae are sufficiently flexible to adapt said array for non-planar contact with said object. -
12. The apparatus of claim 11, wherein said spatular stalks have a Young'"'"'s modulus of 1 megaPascal or greater, and said distal tips have a hydrophobicity, as measured by a surface energy, of between 10-40 mJ/m2.
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13. The apparatus of claim 12, wherein said spatulae terminate at enlarged, rounded ends.
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14. The apparatus of claim 7, wherein said cleaning surface provides a greater area of contact with the unwanted particles than the end effector.
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15. The apparatus of claim 14, wherein the cleaning surface has a surface roughness of less than about 100 nm RRMS.
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16. The apparatus of claim 15, for use in transporting an object having a contact area Ao which is in a defined size range greater than about 5,000 nm2, and for self-cleaning unwanted particles having a contact area Ap in a defined size range between about 100 and 6400 nm2, and less than about 0.1A0, wherein said projections terminate at a hemispherical distal tip having a selected radial dimension R between about 5 and 2,000 nm, and where:
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(i) Ap, ≧
2 π
mm×
R,(ii) the spacing between adjacent projections is such that an unwanted particle makes contact on average with several fold times fewer projections than does the object; and (iii) the projections are formed of a material having a surface energy of between about 10-40 mJ/m2.
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17. The apparatus of claim 16, wherein the radial dimension R and corresponding areal dimensions A, and A, are selected from the group consisting of:
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(i) when R≧
5 nm, Ap, ≧
80 nm2, and Ao≧
800 nm2;(ii) when R≧
25 nm, Ap, ≧
200 nm2, and Ao, ≧
2,000 nm2;(iii) when R≧
50 nm, Ap, ≧
400 nm2, and Ao≧
4,000 nm2;(iv) when R≧
100 nm, Ap, ≧
650 nm2, and Ao, ≧
6,500 nm2;(v) when R≧
250 nm, Ap, ≧
1,600 nm2, and Ao, ≧
16,000 nm2;(vi) when R≧
500 nm, Ap, ≧
3,200 nm2, and Ao≧
32,000 nm2;(vii) when R≧
1,000 nm, Ap, ≧
6,300 nm2, and Ao, ≧
63,000 nm2;(viii) when R≧
1,500 nm, Ap, ≧
9,500 nm2, and Ao, ≧
95,000 nm2; and(ix) when R≧
2,000 nm, Ap, ≧
12,600 nm2, and Ao, ≧
126,000 nm2;
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18. The apparatus of claim 17, wherein the peak to peak spacing between adjacent projections is greater than R.
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19. The apparatus of claim 7, wherein said control unit is configured to operate to carry out operation (iv) by bringing the arm'"'"'s gripping surface into and out of contact with the cleaning surface N times, where N is calculated to effect transfer of a particle from the arm'"'"'s gripping surface to the cleaning surface with high probability.
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20. The apparatus of claim 19, wherein said control unit is configured to operate to carry out operation (iv) by vibrating the arm'"'"'s gripping surface into and out of contact with the cleaning surface for a selected time which is calculated to effect transfer of a particle from the arm'"'"'s gripping surface to the cleaning surface with high probability.
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21. The apparatus of claim 7, wherein said control unit is configured to operate to carry out operation (iii) by (iiia) placing the object on said other workstation and (iiib) rotating the end effector to peel the object away from the arm'"'"'s gripping surface.
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Specification