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Title
Optisch aktives Element und Verfahren zu seiner Herstellung
Date Issued
2000
Author(s)
Jaenchen, H.
Hofmann, W.
Gombert, A.
Wittwer, V.
Patent No
1998-19813690
Abstract
Die Erfindung betrifft optisch aktive Elemente aus einem fuer elektromagnetische Wellen transparenten Kunststoffmaterial sowie Verfahren zu deren Herstellung, wobei solche optischen Elemente an ihren Grenzflaechen zum umgebenden Medium eine zumindest verringerte Reflexion aufweisen sollen. Zur Loesung dieses Problems soll unmittelbar auf der Oberflaeche solcher Elemente zumindest teilweise eine Mikrostrukturierung flaechenhaft ausgebildet werden und dabei die Breiten und Abstaende der einzelnen Strukturelemente kleiner als die kleinste Wellenlaenge der mit dem Element zu beeinflussenden elektromagnetischen Wellen sein.
WO 9950691 A UPAB: 19991201 NOVELTY - The optically active element, of a plastics material transparent to electromagnetic waves, has a microstructure formed at least partially and directly on the surface. The width of the microstructures, and the gaps between them, are smaller than the smallest wavelength of the electromagnetic waves used with the element. DETAILED DESCRIPTION - The free volume within the microstructuring decreases continuously with the increasing depth. The microstructures are formed at intervals on the surface, with the interval length smaller than the smallest wavelength of the electromagnetic waves used with the element. The electromagnetic waves are passed into the element and/or emerge from it. The aspect ratio of the depths and intervals of the microstructures is not more than 2:1. The ratio of the microstructure depth and mean width is not more than 2:1. An INDEPENDENT CLAIM is included for a production process, where the element is injection molded, with a negative image of the microstructure on its surface. Preferred Features: The element can be formed by heat embossing, at a temperature over its softening point, to give the negative image of the microstructure on the surface through the embossing die. The microstructure can also be formed by a laser, which removes surface material. USE - The optical element is a prism, a concave or convex lens, a cylinder lens, a lenticular, a Fresnel's lens or prism or cylinder lens or mirror, used as a rear-view side mirror or a beam guide (all claimed). The optically active element is for use with electromagnetic waves in visible and invisible wavelengths. ADVANTAGE - The element has a lower reflection on the boundary surfaces with the surrounding medium.
Language
de
Patenprio
DE 1998-19813690 A: 19980327