FTI Presents at SPIE: Metrology of Polymer Optics
The paper titled "Metrology of injection molded polymer optics for a Commercial VR system" discusses the design and evaluation of optical components for VR headsets. It focuses on the use of injection-molded Fresnel lenses, which are lightweight and cost-effective, helping to achieve critical volume and performance requirements for head-mounted displays. The lenses are designed with spherical-convex and aspheric-convex surfaces to achieve high optical performance. Metrology techniques, including white light interferometry and contact profilometry, are used to measure surface roughness and form accuracy. Appropriate metrology techniques and testing processes can ensure high-quality VR experiences by identifying optical aberrations to enhance image resolution.
Tags: injection molded Fresnel polymer lenses, head-mounted displays (HMD), field of view, optical metrology
The paper titled "Metrology of injection molded polymer optics for a commercial VR system" by Matthew Kyrish, Jeanette Miller, Margaret Fraelich, Oscar Lechuga, Richard Claytor, and Nelson Claytor, discusses the critical role of metrology in the manufacturing of polymer optics for virtual reality (VR) systems.
The paper covers polymer optics concepts that are applicable to a range of display applications:
- Importance of Metrology in VR Optics:
- VR and augmented reality (AR) devices require high-quality optical components to achieve immersive experiences. The paper emphasizes the necessity of precise metrology to ensure the quality of these components, particularly injection-molded Fresnel lenses.
- Accurate metrology is essential to maintain high resolution, good contrast, and low weight in VR head-mounted displays (HMDs), which are critical for consumer satisfaction.
- Lens Design and Manufacturing: The paper lays out the design of a VR optical system that includes custom tooling fabricated via diamond turning to injection mold acrylic lenses. Each optical channel consists of two lenses with different spherical and aspheric surfaces. The exploration of the use of injection molded polymer Fresnel lenses as compared to traditional spherical or aspherical lenses to achieve a compact form factor can be relevant to a range of optical systems where weight and cost are make-or-break performance concerns.
- Metrology Techniques: Surface finish and lens profiles were measured using a white light interferometer and a contact profilometer, respectively. The paper provides detailed metrology results, including surface roughness and form errors. Metrology is a common constraint for innovative optical designs--you can't make it if you can't measure it. This paper explores the usefulness and constraints of interferometry and profilometry and their use in testing processes.
- System Performance: The assembled VR system's performance was demonstrated using commercial VR software. The paper discusses the impact of manufacturing errors on image quality and suggests improvements for future designs. The authors highlight the impact of stray light on an immersive VR experience.
- Future Directions: The paper suggests future improvements in VR lens manufacturing, including more accurate surface forms and better metrology techniques to enhance system performance. Quantitative performance measurements, such as modulation transfer function (MTF), are recommended for evaluating assembled VR systems.
Overall, this paper underscores the significance of precise metrology in the production of high-quality polymer optics for VR systems. It provides valuable insights into the design, manufacturing, and performance evaluation of VR lenses, making it an important reference for systems engineers and optical engineers working in AR/VR, and other head-mounted display programs.
Access the paper in the SPIE Digital Library.