Method and apparatus for high precision variable rate material removal and modification

• US 6,156,030 A
• Filed: 04/03/1998
• Issued: 12/05/2000
• Est. Priority Date: 06/04/1997
• Status: Expired due to Fees

• Current Assignee: Beam Technologies, Inc.
• Original Assignee: Beam Technologies, Inc.
• Inventors: Neev, Joseph
• Primary Examiner(s): Peffley, Michael
• Assistant Examiner(s): YARNELL, BRYAN KEITH
• Application Number:
  US09/054,834
• Time in Patent Office: 977 Days
• Field of Search: 606/2, 606/4-6, 606/9, 606/10-12, 606/13, 606/27, 606/28, 606/32, 606/34, 606/41, 505/474, 505/412, 427/596, 427/58, 65/61, 219/121.6, 219/121.61, 219/200, 219/209, 219/220, 433/29, 433/215, 216/65, 216/67, 216/94
• US Class Current: 606/10
• CPC Class Codes: A61B 18/20 using laser
• CPC Class Codes: A61B 18/26 for producing a shock wave, e.g. laser lithotripsy
• CPC Class Codes: A61B 2017/00061 spectrum
• CPC Class Codes: A61B 2017/00172 Pulse trains, bursts, intermittent continuous operation
• CPC Class Codes: A61B 2018/00636 Sensing and controlling the application of energy
• CPC Class Codes: A61B 2018/00642 with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/00666 using a threshold value
• CPC Class Codes: A61C 1/0046 Dental lasers surgical lasers A61B18/20; working by laser beam in general B23K26/00; lasers per se H01S3/00
• CPC Class Codes: A61F 2009/00844 Feedback systems
• CPC Class Codes: A61F 2009/00872 Cornea
• CPC Class Codes: A61F 9/00802 for photoablation
• CPC Class Codes: A61F 9/00825 for photodisruption
• CPC Class Codes: B23K 2103/32 Material from living organisms, e.g. skins
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 2103/52 Ceramics
• CPC Class Codes: B23K 26/0096 Portable laser equipment, e.g. hand-held laser apparatus surgical laser instruments A61B18/20, Dental Lasers A61C1/0046, Hand-held laser dental apparatus for curing resins A61C19/004
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less
• CPC Class Codes: B23K 26/064 by means of optical elements, e.g. lenses, mirrors or prisms
• CPC Class Codes: B23K 26/0643 comprising mirrors
• CPC Class Codes: B23K 26/0665 : by beam condensation on the workpiece, e.g. for focusing
• CPC Class Codes: B23K 26/067 : Dividing the beam into multiple beams, e.g. multifocusing
• CPC Class Codes: B23K 26/0676 : into dependently operating sub-beams, e.g. an array of spots with fixed spatial relationship or for performing simultaneously identical operations
• CPC Class Codes: B23K 26/18 : using absorbing layers on the workpiece, e.g. for marking or protecting purposes
• CPC Class Codes: B23K 26/40 : taking account of the properties of the material involved
• CPC Class Codes: B23K 26/53 : for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
• CPC Class Codes: G01N 21/718 : Laser microanalysis, i.e. with formation of sample plasma

Abstract

A method and apparatus is disclosed for fast precise material processing and modification which minimizes collateral damage. Utilizing optimized, pulsed electromagnetic energy parameters leads to an interaction regime which minimizes residual energy deposition. Advantageously, removal of cumulative pulse train residual energy is further maximized through the rapid progression of the ablation front which move faster than the thermal energy diffusion front, thus ensuring substantial removal of residual energy to further minimize collateral thermal damage.

Claims

1. A method for ablating material with directed energy, the method comprising:

a) determining at least one characteristic of the material to be ablated, determining at least one characteristic of the material to be ablated comprising;

i) ablating the material with a pulse of the directed energy;

ii) determining the approximate quantity of the material ablated; and

iii) determining the approximate quantity of the material permanently modified;

b) defining a pulse of the directed energy which increases a ratio of a quantity of the material which will be ablated thereby with respect to a quantity of the material which will be permanently modified thereby, the characteristic(s) of the material determined in step (a) at least partially defining the pulse; and

c) ablating the material with at least one pulse of directed energy which is defined according to step (b);

d) wherein ablating the material with directed energy defined according to step (b) minimizes undesirable permanent modification of the material.

2. The method as recited in claim 1, wherein the directed energy comprises laser radiation.

3. The method as recited in claim 1 wherein the directed energy comprises light from at least one of an LED, a fluorescent lamp, and/or incandescent lamp.

4. The method as recited in claim 1 where the directed energy comprises incandescent light.

5. The method as recited in claim 1 wherein the characteristic(s) of the material determined comprise at least one of the thermal conductivity, effective electromagnetic energy penetration depth, material energy gap between valence and conduction bands, material density, material strength.

6. A device for ablating material with directed energy, the device comprising:

a) a sensor for determining at least one characteristic of the material to be ablated;

b) an energy radiating device for directing a pulse of energy at the material; and

c) a controller for controlling the energy radiating device so as to define a pulse rate of the directed energy which increases a ratio of the quantity of the material which will be ablated thereby with respect to the quantity of the material which will be permanently modified thereby;

d) wherein ablating the material with a plurality of directed energy pulses having a sufficient pulse rate as to increase the ratio of the quantity of the material which will be ablated thereby with respect to the quantity of the material which will be permanently modified thereby minimizes undesirable permanent modification of the material.

7. A device for material modification and processing, the device comprising:

a) an energy radiating device for directing a plurality of pulses of energy at the material, the pulses having a sufficient pulse rate so as to increase a ratio of the quantity of the material which is ablated thereby with respect to quantity of the material which is permanently modified thereby; and

b) a controller for controlling the energy radiating device, the controller configuring the pulse directed therefrom so as to increase a ratio of the quantity of the material which is permanently modified thereby;

c) a means for modifying said energy radiating device output energy wavelength;

d) wherein ablating the material with a plurality of directed energy pulses and with output parameters configured to increase the ratio of the quantity of the material which is ablated thereby with respect to the quantity of the material which is permanently modified thereby minimizes undesirable modification of the material.