Browse Prior Art Database

Alternation of Interferometer

IP.com Disclosure Number: IPCOM000041732D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

George, OE: AUTHOR [+2]

Abstract

In the manufacture of delicate parts such as magnetic heads, it is often necessary to obtain discontinuous coplanar surfaces. To determine whether two such surfaces are coplanar, an interferometer is used to measure the coplanarity of the surfaces. One such interferometer uses a monochromatic helium neon light source to provide an interference pattern which can be used to determine the relative coplanarity of discontinuous surfaces. However, the monochromatic light source provides a pattern in which it is difficult to distinguish the central fringe from the two discontinuous surfaces so that an accurate comparison of planarity can be made.

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Alternation of Interferometer

In the manufacture of delicate parts such as magnetic heads, it is often necessary to obtain discontinuous coplanar surfaces. To determine whether two such surfaces are coplanar, an interferometer is used to measure the coplanarity of the surfaces. One such interferometer uses a monochromatic helium neon light source to provide an interference pattern which can be used to determine the relative coplanarity of discontinuous surfaces. However, the monochromatic light source provides a pattern in which it is difficult to distinguish the central fringe from the two discontinuous surfaces so that an accurate comparison of planarity can be made. This problem can be overcome by providing a white light source to the interferometer for the purpose of locating the position of the central fringe from the two discontinuous surfaces, and then using the monochromatic light source to define the degree of planarity. The interferometer is shown schematically in Figs. 1 and 2. Fig. 1 shows a specimen 1 exposed to monochromatic light, and Fig. 2 shows specimen 1 exposed to white light. Monochromatic light travels from laser source 2, through beam splitter 3 to specimen 1 and reference mirror 4. The generated interference fringe pattern is reflected by mirror 5 to camera 6. To expose the specimen to white light, a port 7 is provided. Right-angle prism 11 is rotated to transmit the white light through beam splitter 3 to specimen 1 and reference mirror 4....