Parallelism Control Between the Press-Fit Head and Barrel Holder in Lens Press-Fitting

・Issues

In the lens press-fitting process, parallelism between the press-fit head and barrel holder is a critical control parameter that directly affects optical performance. Even a slight parallelism error can cause lens tilt, decentering, or optical-axis misalignment, leading to lower MTF and reduced yield. Conventional checks using dial gauges require considerable time and are prone to operator-to-operator variation. A method capable of evaluating parallelism quickly and accurately was therefore needed.

・Solutions

A parallelism sensor is positioned between the press-fit head and barrel holder. Laser beams are directed upward and downward, and the reflected light is measured to determine the angles of both surfaces simultaneously. Parallelism is calculated in real time from the angular difference between the two surfaces, enabling faster and more accurate positioning than conventional dial-gauge measurement. The method also streamlines accuracy checks during equipment setup, fixture replacement, and maintenance, reducing adjustment time and improving quality.