| US 7,531,772 B2 | ||
| Apparatus for translational displacement of a lens in a laser focussing optical system | ||
| Peter S. Dullin, Gilching (Germany); Alistair Baillie Gill, Thaining (Germany); and John Spang, Blackburn (United Kingdom) | ||
| Assigned to Raylase AG, Wessling (Germany) | ||
| Filed on Sep. 30, 2005, as Appl. No. 11/239,081. | ||
| Claims priority of application No. 10 2004 050 916 (DE), filed on Oct. 19, 2004. | ||
| Prior Publication US 2007/0030547 A1, Feb. 08, 2007 | ||
| Int. Cl. G02B 7/04 (2006.01); G02B 15/14 (2006.01) | ||
| U.S. Cl. 250—201.5 [250/201.4; 359/696; 359/698] | 6 Claims |
| 1. An apparatus for automatically shifting a lens of a laser focusing optical system, the lens carrying out translational
movement along an optical axis, comprising:
at least one motor;
at least one linkage;
a carriage; and
a means for determining the position of the lens along the direction of translational motion by means of an optical signal,
wherein the lens is moved by the at least one motor which carries out rotational movement, the rotational movement being converted
by the at least one linkage into translational movement to displace the carriage on which the lens is mounted,
wherein the means for determining the position of the lens comprises at least two light sources, and at least two light detectors,
all being arranged rigidly with respect to the movable lens and further comprises at least one cover moving together with
the lens and entering into an optical path between the light sources and the light detectors when the lens is being shifted,
and
wherein the at least one cover is arranged with respect to the light sources and the light detectors such that shifting of
the lens in one direction will displace a first part of the cover into a first optical path between a first light source and
a first light detector, whereas a second part of the cover becomes displaced out of a second optical path between a second
light source and a second light detector, the lens position being determined based on the ratio of the light intensities measured
by the first and second light detectors.
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