Method and apparatus for treating surfaces and ablating surface material

• US 6,288,362 B1
• Filed: 04/24/1998
• Issued: 09/11/2001
• Est. Priority Date: 04/24/1998
• Status: Expired due to Term

• Current Assignee: General Lasertronics Corporation
• Original Assignee: General Lasertronics Corporation
• Inventors: Thomas, James W., OʼBanion, Laura M., OʼBanion, Roland
• Primary Examiner(s): MOORE, CHRISTOPHER K
• Application Number:
  US09/066,039
• Time in Patent Office: 1,236 Days
• Field of Search: 219/121.6, 219/121.84, 153/39
• US Class Current: 219/121.84
• CPC Class Codes: B08B 7/0042 by laser
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/06 Shaping the laser beam, e.g. by masks or multi-focusing
• CPC Class Codes: B23K 26/0648 comprising lenses
• CPC Class Codes: B23K 26/0665 by beam condensation on the workpiece, e.g. for focusing
• CPC Class Codes: B23K 26/123 in an atmosphere of particular gases
• CPC Class Codes: B23K 26/14 using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor B23K26/12 takes precedence
• CPC Class Codes: B23K 26/1462 Nozzles; Features related to nozzles
• CPC Class Codes: B23K 26/703 Cooling arrangements by using a fluid stream B23K26/14

Abstract

A system for treating surface material overlying a substrate, and more particularly, to a system for ablating contaminates and other unwanted material from a worksite using a pulsed laser beam. The system includes three main sub-systems: a back end (30), a work head (100), and an umbilical tube (88) to protect conduits communicating between the back end (30) and the work head (100). The back end (30) includes heavy and bulky equipment such as a laser (32), chiller, pressurized air source (70), suction system, waste containment system, and electric power source (78). A conveyance such as a trailer may enclose the back end (30) to make it transportable. The work head (100) includes lightweight equipment such as scanning mirrors, optics, and camera (130). During operation, the work head (100) is pressed against the surface material and the laser (32) activated. Then scanning mirrors within the work head (100) arrange pulses from the laser beam according to a selected raster and dither pattern and direct them to the surface material. Ablated detritus may be suctioned through a conduit through the work head (100) and thence to the waste containment system in the back end (30). Electric power, laser energy, control and monitor signals, air, and suction are transported between the back end (30) and the work head (100) through the conduits encased within the umbilical tube (88).

Claims

1. An apparatus for treating surface material on a substrate comprising:

a back end system comprising;

a source of pressurized gas feeding into a first conduit, the first conduit extending from the back end to the work head;

means for suctioning waste material through a second conduit, the second conduit extending from the back end to the work head;

means for filtering waste material from the means for suctioning;

means for supplying electric power to the back end;

means for supplying electric power to a work head through a third conduit, the third conduit extending from the back end to the work head;

a laser capable of emitting a pulsed beam of coherent electromagnetic radiation;

a chiller for refrigerating a coolant;

means for circulating the coolant about the laser;

means for circulating the coolant to a work head through a fourth conduit, the fourth conduit extending from the back end to the work head;

means for monitoring the operation of the work head, the means for monitoring communicating with the work head through a fifth conduit, the fifth conduit extending from the back end to the work head;

control means for directing the operation of the work head, the control means communicating with the work head through a sixth conduit, the sixth conduit extending from the back end to the work head;

a light source capable of generating a beam of visible light, the visible light transported from the back end to the work head through a seventh conduit, the seventh conduit extending from the back end to the work head;

one or more lenses positioned to collimate and to focus the pulsed beam;

an optic fiber, capable of transporting the pulsed beam, positioned to accept the pulsed beam at a first face after the pulsed beam is collimated and focused;

the optic fiber, further having a core, a cladding, a body, and a second face, the body extending from the back end to the work head; and

the core having a diameter at the first face sufficiently large to accept the pulsed beam;

a flexible umbilical cord, connecting the back end with the work head, surrounding the body of the optic fiber, surrounding the first, second, third, fourth, fifth, sixth, and seventh conduits, and comprising means for providing strain relief;

the work head comprising;

a shell with an interior and an exterior wherein the interior contains;

the second face of the optic fiber positioned to deliver the pulsed beam to optic elements;

the optic elements arranged to re-collimate and re-focus the pulsed beam so that the surface material is substantially in the focal plane of the re-collimated and re-focused pulsed beam;

a scanner to scan the re-collimated and re-focused pulsed beam relative to the surface material wherein the scanned pulsed beam is directed to a window positioned between the shell and the surface material, the window transparent to the scanned pulsed beam;

a seal surrounding the window and obstructing detritus from the surface material from entering the shell interior;

the seventh conduit directing the beam of visible light through the window so that the surface material is illuminated;

a camera pointing essentially perpendicular at the window so that the camera monitors illuminated surface material;

signals from the camera directed to one or more monitors in the work head and the back end, the signals communicated to the back end through the fifth conduit;

a control system coordinating work head systems;

a control system feeding operation information to the back end through the sixth conduit and to an operator of the work head;

the second conduit transporting suctioning through the seal;

a first conduit transporting the gas passes from the umbilical cord into the shell interior and through the seal;

an eighth conduit extending from the work head control system through the seal, the eighth conduit communicating interlock signals;

a tap in the first conduit creating gas pressure within the shell interior greater than ambient air pressure on the outside of the shell;

a nozzle attached to the exterior of the shell, and surrounding the seal and the window, wherein the nozzle includes flexible material along the perimeter of the nozzle to surround and to contact the surface material;

the nozzle further including safety interlock points, an air knife, and a waste hose wherein;

the safety interlock points pass interlock signals through the eighth conduit extending into the work head;

the air knife obtains pressurized gas from the first conduit extending through the work head;

the waste hose passes waste from the surface material to the second conduit; and

the exterior of the shell including means for the operator to monitor and control the operation of the work head.

2. An apparatus for transporting the apparatus of claim 1 comprising:

a conveyance containing the back end system;

means for connecting the umbilical cord to the back end system and the work head; and

means for stowing the work head within the conveyance.