Advances in the design and manufacturing of novel freeform optics

Abstract

Freeform optics has become the most prominent element of the optics industry. Advanced freeform optical designs supplementary to ultra-precision manufacturing and metrology techniques have upgraded the lifestyle, thinking, and observing power of existing humans. Imaginations related to space explorations, portability, accessibility have also witnessed sensible in today’s time with freeform optics. Present-day design methods and fabrications techniques applicable in the development of freeform optics and the market requirements are focussed and explained with the help of traditional and non-traditional optical applications. Over the years, significant research is performed in the emerging field of freeform optics, but no standards are established yet in terms of tolerances and definitions. We critically review the optical design methods for freeform optics considering the image forming and non-image forming applications. Numerous subtractive manufacturing technologies including figure correction methods and metrology have been developed to fabricate extreme modern freeform optics to satisfy the demands of various applications such as space, astronomy, earth science, defence, biomedical, material processing, surveillance, and many more. We described a variety of advanced technologies in manufacturing and metrology for novel freeform optics. Next, we also covered the manufacturing-oriented design scheme for advanced optics. We conclude this review with an outlook on the future of freeform optics design, manufacturing and metrology.

Random Silica-Glass Microlens Arrays Based on the Molding Technology of Photocurable Nanocomposites

“…40 The millimeter scale machining dimensions and economic unfriendliness make the first two methods unsuitable for large-size microstructure machining. 41,42 Wet etching is an uncontrollable process and places demanding requirements on the etching solution and the mask layer. Additive manufacturing has highly processing flexibility and is widely used in many fields of great relevance to our lives.…”

“…Due to these characteristics, the primary strategies for processing silica-glass components are cold processing, subtractive manufacturing, and wet etching . The millimeter scale machining dimensions and economic unfriendliness make the first two methods unsuitable for large-size microstructure machining. , Wet etching is an uncontrollable process and places demanding requirements on the etching solution and the mask layer. Additive manufacturing has highly processing flexibility and is widely used in many fields of great relevance to our lives. − In recent years, digital light processing (DLP) and femtosecond direct laser writing (Fs-DLW) in additive manufacturing have also been used to fabricate silica glass in combination with “liquid glass” and get results. − Nevertheless, the inherent machining precision, the roughness of DLP, and the low machining efficiency of Fs-DLW make both technologies inadequate for manufacturing large-area microstructures.…”

Automated design of freeform imaging systems for automotive head-up display applications

“…With the fast development of aberration theory [4,5] and optical manufacturing technologies [6,7], freeform surfaces have been applied in many different areas, such as LED illumination [8,9], head-mounted displays [10,11], hyperspectral systems [12], remote sensing systems [13], and so on. Many scholars have explored various automated design methods for freeform surfaces, such as the Simultaneous Multiple Surface (SMS) method [14,15] and partial differential equations (PDEs) method [16,17].…”

Freeform Hybrid Manufacturing: Binderjet, Structured Light Scanning, Confocal Microscopy, and CNC Machining

“…Freeform optics are widely considered a disruptive technology in the optics industry [1][2][3][4]. Kumar et al state that freeform optics differ from traditional optics and provide the following benefits [3]:…”