Development of a metrological reference system for the form measurement of aspheres and freeform surfaces based on a tilted-wave interferometer

Aspheres and freeform surfaces play an important role in today's optics industry. However, the measurement of such complex surfaces is still challenging even with state-of-the-art manufacturing technology, and there is an urgent need in industry for a non-contact, highly accurate reference measurement technique. To meet this demand, at PTB, a metrological reference system for the contact-free form measurement of aspheres and freeform surfaces is under development. The measurement system is based on a tilted-wave interferometer. Advances in computational capabilities have made it possible to solve the complex inverse problems associated with this measurement system and to develop sophisticated analysis procedures for reconstructing the surface under test from the measured interferogram data. In this paper, we will present the status of the tilted-wave interferometer-based measurement system at PTB, describe the analysis procedures we have designed and show initial measurement results. The benefit of the implementation presented here is that it allows insight to be gained into the performance of the measurement system and enables traceable measurements to be established with low uncertainty.

Progress of Spark Plasma Sintering (SPS) Method, Systems, Ceramics Applications and Industrialization

The spark plasma sintering (SPS) method is of great interest to the powder and powder metallurgy industry and material researchers of academia for both product manufacturing and advanced material research and development. Today in Japan, a number of SPS products for different industries have already been realized. Today’s fifth-generation SPS systems are capable of producing parts of increasing size, offering improved functionality, reproducibility, productivity, and cost. For instance, pure nano-Tungsten Carbide WC powder (no additives) is fully densified with a nano-grain-sized structure for glass lens application in the optics industry. The SPS is now moving from scientific academia and/or R&D proto-type materials level usage to practical industry use product stage utilizing in the field of electronics, automotive, mold and die, cutting tools, fine ceramics, clean energy, biomaterials industries, and others. This paper reviews and introduces the peculiar phenomenon of SPS and the progress of SPS technology, method, development of SPS systems, and its industrial product applications.

Reflectors in lighting design

Reflectors and lenses are common optical components used for image formation and the creation of beam patterns and light distributions. While lenses dominate imaging optics in many applications such as cameras and microscopes, reflectors are widely used in lighting and illumination optics. This article presents an overview of reflectors, including common reflector materials, modern design approaches, and applications. This article does not include information about physical and mathematical properties of reflectors; this information is thoroughly covered in optics industry and academic publications. There will be archetypes and examples discussed in the various sections of this article – neither is there any claim for completeness nor are these meant to be absolute. The intention of this article was to draw a comprehensive horizon around reflector applications and most of all their designs for lighting applications.

A Novel Method for Profile Error Analysis of Freeform Surfaces in FTS/STS Diamond Turning

Fast/slow tool servo (FTS/STS) technology plays an important role in machining freeform surfaces for the modern optics industry. The accuracies of these surfaces not only depend on the performance of the FTS/STS but also on the methods of tool path generation (TPG). Current methods of pre-compensating tool nose radius and control dynamics still do not address the inherent profile errors arise from the methods of TPG. Furthermore, it is also not efficient to characterize a freeform surface in the post-machining stage, giving a high risk of failing to meet the accuracy requirements. In this paper, a profile error analysis (PEA) is introduced into the pre-machining stage to address this inherent profile error. PEA is carried out to compare two methods of TPG, namely the constant angle and constant arc methods and optimizes the number of cutting points in the TPG. Thus, the profile accuracy can be pre-determined to meet accuracy requirements by determining the appropriate TPG method with a least number of the cutting points. In the experiments, sinusoidal wave grid and micro-lens array surfaces are fabricated and their profiles successfully achieve the accuracy tolerance of 1 μm. These further credit the capability of PEA as an effective and accurate tool in improving profile accuracies and meeting accuracy requirements.

Seeing the Light

This article discusses innovations and evolution in the optics industry. Local firms teamed with Monroe Community College to hold events that introduced high school students to optics . Paul Ballentine, who analyzes technology opportunities as deputy director of University of Rochester’s Center for Emerging and Innovative Sciences, sees plenty of upside. Light-based systems are continuing to grow, but Rochester’s optics community will have to reinvent itself to thrive. The Rochester Regional Photonics Cluster has morphed into New York Photonics, with additional clusters in Buffalo, central New York, Albany, and Long Island. It now represents hundreds of optics and photonics companies throughout the state. Paul Conrow, who was teaching physical sciences at Rochester’s East High School, is now recruiting 10th graders and showing them Rochester’s optics industry. Conrow presented the idea to the district superintendent, who had been principal in the only school in America with a student eyeglass program. He introduced Conrow to teachers at a sister high school where members of the cluster were helping to plan a precision optics program.