Lens positioning apparatus
The present invention provides an optical analyzer having illumination optics that include a light source, such as a laser or other source, adapted to emit a collimated, or approximately collimated, light beam, and a focusing lens that focuses the beam onto a focus spot within a detection region, wherein the focusing lens is mounted in a lens positioning apparatus that allows for precise positioning of the focus spot within the detection region. The lens positioning apparatus comprises a lens holder adapted to rotate through a small angle around a pivot axis parallel to the optical path, such that the lens holder rotates in a plane perpendicular to the optical path, and an actuator adapted to provide an angular displacement of the lens holder around the pivot axis. The lens holder holds the focusing lens at a first distance from the pivot axis, and is coupled to the actuator at a second distance from the pivot axis, wherein the second distance is larger than the first distance.
1. An optical analyzer comprising:
(a) a light source adapted to emit a collimated or approximately collimated light beam along an optical path;
(b) a focusing lens positioned in the optical path, adapted to focus the light beam onto a focal spot within a sample analysis region;
(c) a lens holder adapted to rotate through an angle around a pivot axis parallel to the optical path, such that the lens holder rotates in a plane perpendicular to the optical path, wherein said focusing lens is mounted in said lens holder at a first radius, R 1 , from said pivot axis;
(d) an actuator adapted to provide an angular displacement of the lens holder around the pivot axis, wherein said actuator is coupled to said lens holder at a second radius, R 2 , from said pivot axis;
wherein R 2 >R 1 .
2. The optical analyzer of claim 1 , wherein said actuator comprises an actuator screw that is linearly extended or retracted by rotation of the screw, and wherein said actuator screw has a tip that is coupled to the lens holder.
3. The optical analyzer of claim 2 , wherein said tip of said actuator screw is coupled to said lens holder through a magnetic coupling.
4. The optical analyzer of claim 1 , wherein R 2 is >2·R 1 .
5. The optical analyzer of claim 1 , wherein R 2 is >3·R 1 .