Opto-Mechanical Urine Microscopy

This project involved the design of a mechanism for an opto-mechanical module and flow cell requiring precise motion control, high repeatability, and mechanical stability without friction or backlash. The design was developed to support optical systems where micron-level positioning accuracy and long-term reliability are critical. The optical bench is part of a automated urine microscopy instrument that identifies and differentiate particle in urine for medical analysis.

Engineering Scope:

• Provide a protective holder for the flow cell that can be positioned accurately in the optical bench.

• Provide means for aligning the lamina of particles in the flow cell to be coincident with the focal plane of the objective lens.

• Provide for computer control of focus position within less than one micron.

• Optical bench is to be sturdy and long-lived.

• Optical bench is to be easy to adjust and service.

Key Design Considerations:

• Elimination of friction and backlash through flexure mechanisms design

• Controlled precise objective micro positing motion control

• Mechanical stability for optical alignment

• Sensitivity to manufacturing tolerances

Means of achieving requirements

• The flexure parallelogram movement is free of stiction and the changes in performance found in ball slides when making repeated small moves.

• Both the stage and the objective lens are mounted on the same surface of the optical bench enclosure. 

• The anti-friction bearing eccentric drive avoids the wear and friction problems typical of screw type actuators.

• Adjustment of the stage is provided by a spherical bearing with its center at the focal plane.

• Fine pitch actuators permit independent adjustment of horizontal and vertical tilt without significant change in focus.

• Aluminum Cast housing for proper refence establishment.