Automatic Cementing Of Achromatic Lens Systems

The manual cementing of doublets requires a high level of mechanical skills and the results could be disappointing if a centration error deteriorates the imaging quality of the achromatic doublet.

With the OptiCentric® Cementing Station developed by TRIOPTICS this cementing process can be significantly simplified and automated for more reliable results. In contrast to the traditional process this new method eliminates the need for precision sample fixtures, and due to the fully automatic procedure it is independent from the mechanical skills and attention of the operator.

The centration error is measured with an autocollimator system in reflection mode according to the ISO 10110-6 standard. With the patented SmartAlign® algorithm the centration of each lens surface within the achromatic doublet is measured automatically and the optimum shift for the upper lens is calculated. This movement is then done within 1-2 seconds with a piezo driven manipulator, achieving a residual centration error between both lenses in the doublet of typically less than 2 microns.

This procedure is independent from the accuracy and stability of any mechanical fixtures since both lenses are directly centered to each other but not to some third mechanical reference. The measurement precision is provided by a high resolution CCD based electronic autocollimator while the sample rotation is achieved by an ultra-high precision air bearing.

A software controlled motorized stage focuses the autocollimator to the center of curvature of each surface for measuring its displacement or tilt. After manual loading the lens pair with added cement the complete centering process including UV curing is done automatically. In total, the complete process of centering and curing takes no longer than a few seconds. Therefore the OptiCentric® Cementing Station is an attractive solution for the series production of achromatic systems.

The instrument software provides records and statistics of the centration results, user definable thresholds for centration tolerances, simple go/no go signals for the final result and a control for the UV lamp.

The cementing station is an add-on to the TRIOPTICS OptiCentric® System for centration error measurement and can be easily adapted to existing instruments with air bearing, but can be also ordered as a turnkey stand-alone system.

Beside the OptiCentric® Cementing Station, the OptiCentric® Bonding Station should not be missed in any optical production. With the OptiCentric® Bonding Station lenses can be assembled and centered to a complete optical system.

SOURCE: TRIOPTICS GmbH