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Optical System for Laser Machining of Narrow Slots

IP.com Disclosure Number: IPCOM000076296D
Original Publication Date: 1972-Feb-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Grimm, MA: AUTHOR

Abstract

Shown in Fig. 1 is an optical system, which allows narrow slots to be cut in thin material by a pulsed laser.

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Optical System for Laser Machining of Narrow Slots

Shown in Fig. 1 is an optical system, which allows narrow slots to be cut in thin material by a pulsed laser.

Beam 12 from pulsed laser 10 is expanded by lens 14 and collimated by lens
16. Resulting expanded and collimated beam 18 is focused through cylindrical lens 20, producing a line of light 23 in focal plane 22 of the same length as the diameter of beam 18. Line 23 is then reduced in length and width by a microscope lens 24 working in the reversed mode and projected as image 26 onto workpiece 28 where a narrow slot is machined.

The focal length of cylindrical lens 20 corresponds to the "tube length" of microscope lens 24. The length, L, of the line formed on workpiece 28 is L = f(2)m/f(1) = Dm where m is the reduction of lens 24, f(2) and f(1) are the focal length of lens 16 and 14, respectively, and D is the diameter of beam 18.

In a modified form, shown in Fig. 2, several slots can be made simultaneously by use of a multielement cylindrical array. Those features in Fig. 2 corresponding to Fig. 1 carry like numerals. Beam 18 is shaped into a rectangular beam 52 by an anamorphic system 54, for example, two cylindrical lenses 20 and 56 arranged confocally with their respective cylinder axes parallel to one another. The ratio of the cylinder focal lengths gives the beam expansion ratio in the direction perpendicular to the direction of the cylinder axis, hence the cylinder axis of elements 54 and 58, 62 are at...