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Scanning Laser Beam Algorithms for Preferred Shaping and Micromachining At Normal Incidence Disclosure Number: IPCOM000014186D
Original Publication Date: 2000-Aug-01
Included in the Prior Art Database: 2003-Jun-19

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A process is disclosed that permits clean 3-dimensional (3D) micromachining of a surface by scanning a pulsed laser spot at normal incidence to the surface. In prior laser micromachining processes, a focused laser spot at normal incidence is moved around the surface to produce material-removal at desired locations. However, material-removal is frequently accompanied by debris deposition. Furthermore, the prior laser micromachining processes provide only 2-D features, but not 3-D features like a sloping surface. This laser scanning process utilizes an algorithm or control program that controls the laser spot diameter s, the scan velocity v, the pulse repetition rate r, and the pulse laser energy E. By controlling these parameters when scanning the pulsed laser spot at normal incidence on the surface, one can produce 3-D features with reduced debris deposited on the surface. For example, to produce a sloping surface, a line L1 is first scanned on the surface at the deepest location of the sloping surface to be produced. L1 is composed of overlapping laser spots, and the depth at L1 is controlled by proper setting of s, v, r, and E. Next, an overlapping scan line L2 is scanned next to L1, typically with some overlap (i.e., the spacing between L1 and L2 is less than the spot diameter s), and the energy E used in L2 is reduced in order to make shallower cuts. By utilizing more overlapping lines, and controlling the pulse energy and the spot-to-spot overlap and the line-to-line overlap, a 3-D slope can be produced. Also, lower-energy scans produce less debris, and by using lower-energy scans to remove debris generated from higher-energy scans, less overall debris is produced on the surface. 1