Published by De Gruyter

Volume 5 Issue 4 - Plastic optics / Guest Editors: Stefan Bäumer and Allen Yi

Issue of Advanced Optical Technologies

Contents
Journal Overview

Publicly Available August 5, 2016

Community

Publicly Available July 27, 2016

News from the European Optical Society

Page range: 265-266

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Publicly Available July 27, 2016

News

Page range: 267-269

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Publicly Available July 21, 2016

Topical issue: Plastic optics

Editorial

Publicly Available July 27, 2016

Topical issue on plastic optics

Stefan Bäumer, Allen Yi

Page range: 275-276

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Tutorial

Publicly Available June 30, 2016

Process influences and correction possibilities for high precision injection molded freeform optics

Lars Dick, Stefan Risse, Andreas Tünnermann

Page range: 277-287

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Abstract

Modern injection molding processes offer a cost-efficient method for manufacturing high precision plastic optics for high volume applications. Besides form deviation of molded freeform optics, internal material stress is a relevant influencing factor for the functionality of a freeform optics in an optical system. This paper illustrates dominant influence parameters of an injection molding process relating to form deviation and internal material stress based on a freeform demonstrator geometry. Furthermore, a deterministic and efficient way for 3D mold correcting of systematic, asymmetrical shrinkage errors is shown to reach micrometer range shape accuracy at diameters up to 40 mm. In a second case, a stress-optimized parameter combination using unusual molding conditions was 3D corrected to reach high precision and low stress freeform polymer optics.

Short Communication

June 23, 2016

Diamond machining of steel molds for optical components

Roland Bohr

Page range: 289-291

Abstract

The requirement of ultra precision diamond machining of lens molds in steel is identified. A solution for this type of machining is presented and results of such a machining in steel compared to standard milling and polishing process are shown.

Review Articles

June 25, 2016

Additive manufacturing of optical components

Andreas Heinrich, Manuel Rank, Philippe Maillard, Anne Suckow, Yannick Bauckhage, Patrick Rößler, Johannes Lang, Fatin Shariff, Sven Pekrul

Page range: 293-301

Abstract

The development of additive manufacturing methods has enlarged rapidly in recent years. Thereby, the work mainly focuses on the realization of mechanical components, but the additive manufacturing technology offers a high potential in the field of optics as well. Owing to new design possibilities, completely new solutions are possible. This article briefly reviews and compares the most important additive manufacturing methods for polymer optics. Additionally, it points out the characteristics of additive manufactured polymer optics. Thereby, surface quality is of crucial importance. In order to improve it, appropriate post-processing steps are necessary (e.g. robot polishing or coating), which will be discussed. An essential part of this paper deals with various additive manufactured optical components and their use, especially in optical systems for shape metrology (e.g. borehole sensor, tilt sensor, freeform surface sensor, fisheye lens). The examples should demonstrate the potentials and limitations of optical components produced by additive manufacturing.

July 26, 2016

Precision injection molding of freeform optics

Fengzhou Fang, Nan Zhang, Xiaodong Zhang

Page range: 303-324

Abstract

Precision injection molding is the most efficient mass production technology for manufacturing plastic optics. Applications of plastic optics in field of imaging, illumination, and concentration demonstrate a variety of complex surface forms, developing from conventional plano and spherical surfaces to aspheric and freeform surfaces. It requires high optical quality with high form accuracy and lower residual stresses, which challenges both optical tool inserts machining and precision injection molding process. The present paper reviews recent progress in mold tool machining and precision injection molding, with more emphasis on precision injection molding. The challenges and future development trend are also discussed.

Research Articles

June 25, 2016

Methodology for the design, production, and test of plastic optical displacement sensors

Maik Rahlves, Christian Kelb, Eduard Reithmeier, Bernhard Roth

Page range: 325-334

Abstract

Optical displacement sensors made entirely from plastic materials offer various advantages such as biocompatibility and high flexibility compared to their commonly used electrical and glass-based counterparts. In addition, various low-cost and large-scale fabrication techniques can potentially be utilized for their fabrication. In this work we present a toolkit for the design, production, and test of such sensors. Using the introduced methods, we demonstrate the development of a simple all-optical displacement sensor based on multimode plastic waveguides. The system consists of polymethylmethacrylate and cyclic olefin polymer which serve as cladding and core materials, respectively. We discuss several numerical models which are useful for the design and simulation of the displacement sensors as well as two manufacturing methods capable of mass-producing such devices. Prior to fabrication, the sensor layout and performance are evaluated by means of a self-implemented ray-optical simulation which can be extended to various other types of sensor concepts. Furthermore, we discuss optical and mechanical test procedures as well as a high-precision tensile testing machine especially suited for the characterization of the opto-mechanical performance of such plastic optical displacement sensors.

July 27, 2016

An integrated approach to design and fabrication of a miniature endoscope using freeform optics

Hui Li, Neil J. Naples, Xin Zhao, Allen Y. Yi

Page range: 335-342

Abstract

Endoscopes are important medical optical devices widely used in minimally invasive surgery. However, manufacturing issues such as tight packaging constraints and tolerance requirements hinder their development. These problems often result in high manufacturing cost or poor image quality. To cope with these issues, in this research, a novel endoscope utilizing an off-axis freeform optics is developed by using an integrated ultraprecision diamond machining process. The major optical components of this endoscope include a prism with two reflective surfaces and a freeform entrance surface. In addition, a doublet and a field lens were added to complete the system design. To validate the feasibility of the endoscope design, single-point diamond turning and rastering processes were utilized to machine the required components. After the lenses were machined, the geometry of the lenses was measured using a white light optical profilometer. The results show that their profiles have a manufacture error of ±2 μm along the optical axis. Lastly, the prototype was assembled and tested to evaluate its imaging performance, including measurement of its modulation transfer function.

July 28, 2016

Wavefront measurement of plastic lenses for mobile-phone applications

Li-Ting Huang, Yuan-Chieh Cheng, Chung-Yen Wang, Pei-Jen Wang

Page range: 343-349

Abstract

In camera lenses for mobile-phone applications, all lens elements have been designed with aspheric surfaces because of the requirements in minimal total track length of the lenses. Due to the diffraction-limited optics design with precision assembly procedures, element inspection and lens performance measurement have become cumbersome in the production of mobile-phone cameras. Recently, wavefront measurements based on Shack-Hartmann sensors have been successfully implemented on injection-molded plastic lens with aspheric surfaces. However, the applications of wavefront measurement on small-sized plastic lenses have yet to be studied both theoretically and experimentally. In this paper, both an in-house-built and a commercial wavefront measurement system configured on two optics structures have been investigated with measurement of wavefront aberrations on two lens elements from a mobile-phone camera. First, the wet-cell method has been employed for verifications of aberrations due to residual birefringence in an injection-molded lens. Then, two lens elements of a mobile-phone camera with large positive and negative power have been measured with aberrations expressed in Zernike polynomial to illustrate the effectiveness in wavefront measurement for troubleshooting defects in optical performance.

July 21, 2016

Diamond turning fabrication of an ultra-compact endoscope

Chih-Yu Huang, Rongguang Liang

Page range: 351-357

Abstract

In this paper, we propose a technique by integrating mechanical mounts into lens elements to fulfill a self-aligned and self-assembled optical system. To prove this concept, we designed, fabricated, and tested an ultra-compact endoscope that adopts this technique. By taking advantages of the specially designed fixture and observing the interference fringes between the lens and fixture, we developed a method to minimize decenter and tilt between the two surfaces of the endoscope lens during the diamond turning fabrication process. The integrated mechanical mounts provide an easy assembly process for the endoscope system while maintaining high accuracy in system alignment. With the application of heat shrink tube as the endoscope system holder and to block stray light, the proposed endoscope system has the advantages of low cost, compact size, and high imaging quality.

About this journal

From 2023 onwards, Advanced Optical Technologies will be published by Frontiers.　For more information on submitting to the journal, please see their submissions page.

Objective

Advanced Optical Technologies is a strictly peer-reviewed scientific journal. The major aim of Advanced Optical Technologies is to publish recent progress in the fields of optical design, optical engineering, and optical manufacturing. Advanced Optical Technologies has a main focus on applied research and addresses scientists as well as experts in industrial research and development.

Volume 5 Issue 4 - Plastic optics / Guest Editors: Stefan Bäumer and Allen Yi

Issue of Advanced Optical Technologies

Cover and Frontmatter

News from the European Optical Society

News

Conference Calendar

Editorial

Topical issue on plastic optics

Tutorial

Process influences and correction possibilities for high precision injection molded freeform optics

Abstract

Short Communication

Diamond machining of steel molds for optical components

Abstract

Review Articles

Additive manufacturing of optical components

Abstract

Precision injection molding of freeform optics

Abstract

Research Articles

Methodology for the design, production, and test of plastic optical displacement sensors

Abstract

An integrated approach to design and fabrication of a miniature endoscope using freeform optics

Abstract

Wavefront measurement of plastic lenses for mobile-phone applications

Abstract

Diamond turning fabrication of an ultra-compact endoscope

Abstract