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Uniform Area Illumination Using Kinoforms

IP.com Disclosure Number: IPCOM000075245D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Burke, MJ: AUTHOR

Abstract

In applications such as optical scanning or the like, it is frequently desirable to illuminate a relatively large area with uniform intensity. A simple, high-efficiency method of transforming incoherent light from a wide variety of sources to the desired intensity distribution is to use a kinoform filter. Kinoforms are a type of phase-only hologram, as described in L. B. Lesem et al, "The Kinoform: A New Wavefront Reconstruction Device", IBM J. Research and Development, March 1969, pages 150-155.

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Uniform Area Illumination Using Kinoforms

In applications such as optical scanning or the like, it is frequently desirable to illuminate a relatively large area with uniform intensity. A simple, high- efficiency method of transforming incoherent light from a wide variety of sources to the desired intensity distribution is to use a kinoform filter. Kinoforms are a type of phase-only hologram, as described in L. B. Lesem et al, "The Kinoform: A New Wavefront Reconstruction Device", IBM J. Research and Development, March 1969, pages 150-155.

In illuminator 10, light rays 11 from an arbitrarily shaped incoherent source 12 are transmitted through kinoform 13. Transformed rays 14 are then projected onto document 15 with a uniform intensity within are 16. At least two types of kinoform 13 will produce the desired light distribution in area 16. The first type is one whose impulse response is a square (or other desired area shape) filled with a pattern of points. Illumination of such a kinoform by an extended source 12 produces a uniformly lighted square (or other shape) 16 whose dimensions are the size of the original source 12. The second type of kinoform is one whose response is matched to the known intensity distribution of source 12. This particular source then produces uniform intensity in the desired area 16.

The achievement of uniform intensities has been particularly described. Other intensity-distribution functions may also be produced by the foregoing technique...