US4987286A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for removing minute particles from a surface
Assignee: University of Iowa Research Foundation
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Filing: 1989-10-30
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Granted: 1991-01-22
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Expires: 2009-10-30
Abstract
Abstract Method and apparatus for removing minute particles (as small as submicron) from a surface to which they are adhered. An energy transfer medium is interposed between each particle to be removed and the surface to which the particles are adhered. The medium is an irradiated with laser energy at a wavelength which is strongly absorbed by the medium. The medium absorbs sufficient energy to cause explosive evaporation with sufficient force to dislodge the particles. Preferably means are provided to remove dislodged particles to prevent redeposit on the surface.
Inventors
- 👤 Susan D. Allen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:29
CPC Classifications
B; B08; B08B; B08B7/00; B08B7/0035; B08B7/0042; B23; B23K; B23K26/00; B23K26/36; B23K26/361
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
64 words
A method of removing particles adhered to a surface comprising the steps of: adsorbing an energy transfer medium into interstices between the particle to be removed and the surface, irradiating the medium in the interstices with laser energy at a wavelength strongly absorbed by the medium, absorbing sufficient energy in the medium to cause explosive evaporation thereof with sufficient force to dislodge the particle.
Claim 2
Independent Claim
64 words
A method of removing particles adhered to a surface comprising the steps of: adsorbing an energy transfer medium into interstices between the particle to be removed and the surface, irradiating the medium in the interstices with laser energy at a wavelength strongly absorbed by the medium, absorbing sufficient energy in the medium to cause explosive evaporation thereof with sufficient force to dislodge the particle.
Claim 3
Dependent Claim
52 words
The method as set forth in claim 1 further comprising the step of maintaining the surface at a temperature adequate to desorb said medium from the surface while allowing the medium to remain in the interstices, thereby to concentrate the energy transfer medium between the particles to be removed and the surface.
Claim 4
Dependent Claim
15 words
The method as set forth in claim 1 wherein the energy transfer medium is water.
Claim 5
Dependent Claim
28 words
The method as set forth in claim 3 wherein the laser is an Er:YAG laser having a wavelength of about 2.94 microns which is strongly absorbed by water.
Claim 6
Dependent Claim
28 words
The method as set forth in claim 1 further comprising the step of removing particles after they are dislodged and before they can again adhere to the surface.
Claim 7
Dependent Claim
29 words
The method as set forth in claim 5 wherein the explosive evaporation is accomplished in a vacuum for removing dislodged particles before they can again adhere to the surface.
Claim 8
Dependent Claim
45 words
The method as set forth in claim 5 wherein the step of removing dislodged particles comprises impinging a gas jet onto the surface for imparting a velocity to the dislodged particles adapted to remove the dislodged particles before they can again adhere to the surface.
Claim 9
Dependent Claim
59 words
The method as set forth in claim 1 wherein the adsorbing step comprises dosing the surface with liquid while maintaining the surface at a temperature sufficiently low to cause adsorption of liquid into the interstices, and raising the temperature of the surface to a level sufficient to desorb surface adhered liquid while retaining the liquid adsorbed in the interstices.
Claim 10
Independent Claim
83 words
A method of removing particles adhered to a surface comprising the steps of: interposing between each particle to be removed and the surface to which the particle is adhered an energy transfer medium, irradiating the surface carrying the adhered particles and energy transfer medium with laser energy of a wavelength highly absorbed by the interposed medium, and absorbing sufficient laser energy in the interposed medium to transform said laser energy into kinetic energy in the medium thereby dislodging the particles from the surface.
Claim 11
Independent Claim
83 words
A method of removing particles adhered to a surface comprising the steps of: interposing between each particle to be removed and the surface to which the particle is adhered an energy transfer medium, irradiating the surface carrying the adhered particles and energy transfer medium with laser energy of a wavelength highly absorbed by the interposed medium, and absorbing sufficient laser energy in the interposed medium to transform said laser energy into kinetic energy in the medium thereby dislodging the particles from the surface.
Claim 12
Dependent Claim
54 words
The method as set forth in claim 9 further comprising the step of maintaining the surface at a temperature adequate to desorb said medium from the surface while allowing the medium interposed between the particles and the surface to remain, thereby to concentrate the liquid between the particles to be removed and the surface.
Claim 13
Dependent Claim
15 words
The method as set forth in claim 9 wherein the energy transfer medium is water.
Claim 14
Dependent Claim
26 words
The method as set forth in claim 11 wherein the laser is an Er:YAG laser having a wavelength of about 2.94 microns strongly absorbed by water.
Claim 15
Dependent Claim
26 words
The method as set forth in claim 9 further comprising the step of removing dislodged particles before the dislodged particles can again adhere to the surface.
Claim 16
Dependent Claim
29 words
The method as set forth in claim 13 wherein the explosive evaporation is accomplished in a vacuum for removing dislodged particles before they can again adhere to the surface.
Claim 17
Dependent Claim
45 words
The method as set forth in claim 13 wherein the step of removing dislodged particles comprises impinging a gas jet onto the surface for imparting a velocity to the dislodged particles adapted to remove the dislodged particles before they can again adhere to the surface.
Claim 18
Dependent Claim
61 words
The method as set forth in claim 9 wherein the step of interposing comprises dosing the surface with liquid while maintaining said surface at a temperature sufficiently low to adsorb liquid into interstices between the particle and the surface, and raising the temperature of the surface to a level sufficiently high to desorb surface liquid while retaining liquid in the interstices.
Claim 19
Independent Claim
99 words
A method of removing particles adhered to a surface comprising the steps of: dosing the surface with liquid while maintaining the temperature of the surface at a level adequate to cause adsorption of liquid in interstices between the particles and the surface, raising the temperature of the surface to a level adequate to desorb any surface liquid while maintaining liquid in the interstices, irradiating the surface with laser energy of a wavelength highly absorbed by the liquid in the interstices, and absorbing sufficient energy in the liquid to cause explosive evaporation thereof with sufficient force to dislodge the particles.
Claim 20
Independent Claim
99 words
A method of removing particles adhered to a surface comprising the steps of: dosing the surface with liquid while maintaining the temperature of the surface at a level adequate to cause adsorption of liquid in interstices between the particles and the surface, raising the temperature of the surface to a level adequate to desorb any surface liquid while maintaining liquid in the interstices, irradiating the surface with laser energy of a wavelength highly absorbed by the liquid in the interstices, and absorbing sufficient energy in the liquid to cause explosive evaporation thereof with sufficient force to dislodge the particles.
Claim 21
Independent Claim
96 words
A system for removing particles adhered to a surface, the system comprising in combination: means for mounting the surface for particle removal, means for applying an energy transfer medium to said surface in such a way as to create a layer of said medium between the particles and said surface to which the particles are adhered, laser means for irradiating the surface and causing absorption of laser energy in the medium, and means for directing adequate laser energy to the medium to cause explosive evaporation of the medium in the layer thereby to dislodge the particles.
Claim 22
Independent Claim
96 words
A system for removing particles adhered to a surface, the system comprising in combination: means for mounting the surface for particle removal, means for applying an energy transfer medium to said surface in such a way as to create a layer of said medium between the particles and said surface to which the particles are adhered, laser means for irradiating the surface and causing absorption of laser energy in the medium, and means for directing adequate laser energy to the medium to cause explosive evaporation of the medium in the layer thereby to dislodge the particles.
Claim 23
Dependent Claim
38 words
The system as set forth in claim 18 in which the means for directing further includes means for limiting the amount of laser energy absorbed by the surface to a level below that capable of damaging said surface.
Claim 24
Dependent Claim
16 words
The system as set forth in claim 18 wherein the energy transfer medium is a liquid.
Claim 25
Dependent Claim
67 words
The system as set forth in claim 20 further including means for reducing the temperature of the surface during application of the liquid energy transfer medium to assure that liquid is adsorbed on the surface and between the particles and the surface, and means for raising the temperature of the surface after liquid application to desorb surface liquid while maintaining liquid between the particles and the surface.
Claim 26
Dependent Claim
34 words
The system as set forth in claim 18 wherein the liquid is water and the laser means comprises an Er:YAG laser having a wavelength of about 2.94 microns which is strongly absorbed by water.
Claim 27
Dependent Claim
24 words
The system as set forth in claim 18 further including means for removing dislodged particles before said particles can again adhere to the surface.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-21 | 1994-07-23 | 1995-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-21 | 1998-07-23 | 1999-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-21 | 2002-07-23 | 2003-01-22 | $7700.00 | Window Closed / Lapsed |