Renso J. M. Zwiers

Aspherical lenses produced by a fast high-precision replication process using UV-curable coatings

Diffraction-limited aspherical lenses for audiodisc systems have been produced in a high-precision lens replication process using UV-polymerizable coatings. The requirements and merits of this process are described. The optical performance of the lenses is determined by the accuracy of the replication process and the physical properties of the photopolymerized coating. The optical and mechanical behavior of the replication coating is examined in detail over a broad temperature range.

Development of a new low-stress hyperred LED encapsulant

The development of a transparent encapsulant for a hyperred LED is presented. The encapsulant was evaluated and compared with various encapsulants from several suppliers. All encapsulants were evaluated by monitoring the behavior of the LEDs in laboratory quality tests and performing failure analysis. The correlation between chemistry and final optical and mechanical properties of the encapsulant, plus their influence on the lifetime of the LED crystal, is elucidated. Three failure mechanisms are commonly observed: corrosion, mechanical stress, and open circuits due to wire breaking. By careful selection of chemistry and optimization of processing and manufacturing procedures, these can be circumvented. The resulting LED has a high light output, good stability during operation under various conditions, and few open circuits in temperature cycling, even after 200 cycles. Finally, the encapsulant does not show any yellowing under extreme weathering conditions or during lifetime. >

A Replicated Bi-Aspherical Readout Lens For Optical Disc Systems.

A diffraction-limited bi-aspherical readout lens for the digital audio disc system has been designed and developed based on a high-precision lens replication process using UV-polvmerizable coatings. This single element read-out lens consists of a hall-shaped quartz substrate with two aspherical replicated coating surfaces. The design of the bi-aspherical lens is presented and its production described. The optical performance of the lenses proved to be reasonable with an rms-OPD of 0.055 λ, the primary lens aberration being spherical aberration.

Materials for replication technology — A fast & high-precision manufacturing method for optical components

Abstract This article describes the processing characteristics and optical and mechanical properties over abroad temperature range (−30°C