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Astigmatic Aberration Correction

IP.com Disclosure Number: IPCOM000090597D
Original Publication Date: 1969-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 21K

Publishing Venue

IBM

Related People

Habegger, MA: AUTHOR

Abstract

Astigmatism occurs in a beam of light propagated through a birefringent plate as a set of extraordinary rays. This device corrects for the astigmatic distortions produced by the birefringent plate. X birefringent device is formed of pieces 1 and 2 which have the same thickness. Optic axes 3 and 4 of these pieces are orthogonal to one another. Optic axis 3 is in the plane of the paper and optic axis 4 is perpendicular to it. Half-wave plate 5 which can be formed of mica is inserted between pieces 1 and 2. Plate 5 rotates the polarization of a light beam emerging from plate 1 by 90 degrees before the beam enters plate 2. If light beam 6 is propagated as a set of ordinary rays through plate 1 it is also propagated as a set of ordinary rays in plate 2 after the rotation of polarization by plate 5.

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Astigmatic Aberration Correction

Astigmatism occurs in a beam of light propagated through a birefringent plate as a set of extraordinary rays. This device corrects for the astigmatic distortions produced by the birefringent plate. X birefringent device is formed of pieces 1 and 2 which have the same thickness. Optic axes 3 and 4 of these pieces are orthogonal to one another. Optic axis 3 is in the plane of the paper and optic axis 4 is perpendicular to it. Half-wave plate 5 which can be formed of mica is inserted between pieces 1 and 2. Plate 5 rotates the polarization of a light beam emerging from plate 1 by 90 degrees before the beam enters plate 2. If light beam 6 is propagated as a set of ordinary rays through plate 1 it is also propagated as a set of ordinary rays in plate 2 after the rotation of polarization by plate 5. No astigmatic aberration occurs. When beam 6 is propagated as a set of extraordinary rays, it is also propagated as a set of extraordinary rays in plate 2 after the rotation of polarization by plate 5. Beam 6, incident on plate 1 in the same plane as the plane containing optic axis 3, is incident on plate 2 in a plane, normal no the optic axis 4. The result is that the rays in the two orthogonal planes sustain the same amount of refraction and avoid any astigmatic aberrations. The astigmatism correction device can be utilized in transmission type light deflectors such as split angle or Wollaston prism deflectors for correction of astigmatic...