Custom-Sized Microlenses

August 30, 2004

Optical components have joined the trend towards miniaturization. There have, however, been no methods available thus far to produce custom-sized glass lenses. A new process now enables the low-cost, high-volume manufacture of microlenses with extreme dimensions.


Miniaturization is a big issue these days. Micro-optical component manufacturers are increasingly being called upon to produce smaller and smaller lenses. The telecommunications industry, for example, uses them to couple optical signals with multi-fiber connectors. Tiny lenses used in fingerprint sensors for security applications such as checking cards or automobile anti-theft systems are also in high demand. Although these tiny components are typically made from plastic materials, the use of borosilicate glass is on the rise. This type of glass is highly scratch resistant, physically stable in shape and mechanically robust.

However, structuring glass in microtechnical processes has its limits. Currently available methods restrict the structural height of plasma-etched glass. Optical properties such as focal length can be customized to the particular application only through the selection of the material or the curvature of the lens. And if the material has been pre-selected, the only option to create the required optical properties is to produce lenses of various shapes and heights. Vacuum-based plasma etching is a costly, time-consuming process. Gases are fed into a vacuum chamber. Having changed into an ionized plasmas, they gradually but slowly erode the glass parts.

Researchers at the Fraunhofer Institute for Silicate Technologies ISIT have come up with a novel process that offers decisive advantages. “With the glass flow process, we can reduce production costs to ten percent of current values,” emphasizes Peter Merz from ISIT. “Moreover, we can achieve 1:1 height to thickness ratios.” This means that a 0.1mm wide lens can have a height of up to 100 micrometers, about the diameter of a human hair. In comparison, plasma etching attains only one-fifth of this value.

Merz explains the viscous deformation process this way: “We begin with a silicon wafer preform. Using a rapid etching procedure, we create tiny depressions in the silicon that conform to the desired lens diameter. A substrate made from borosilicate glass is then hermetically sealed to the silicon preform. Under high temperature, the glass then slumps into the silicon cavity and forms a mould.” Temporal regulation of the temperature determines the topography and height of the lens. The contactless forming process results in lenses with very low surface roughness, hence they require no additional finishing.

Source: Fraunhofer-Gesellschaft

Explore further: Microfabrication leads to a new microscopy method

Related Stories

Microfabrication leads to a new microscopy method

June 18, 2015

With the aim of providing a simple, yet versatile microscopy technique that can identify single proteins anywhere within a cell, and allow cellular organization to be assessed in 3D, researchers at the Mechanobiology Institute ...

Toshiba Glass shown at Ceatec in Japan

October 9, 2014

Toshiba plans to introduce its own brand of smart glasses called Toshiba Glass, part of the peeks, prototypes and general buzz events at Ceatec in Japan.

Superhydrophobic glass coating offers clear benefits

May 11, 2015

A moth's eye and lotus leaf were the inspirations for an antireflective water-repelling, or superhydrophobic, glass coating that holds significant potential for solar panels, lenses, detectors, windows, weapons systems and ...

Industry's largest glass-molded aspheric lens

February 13, 2015

Panasonic Corporation today announced that it has developed the industry's largest glass-molded aspheric lens measuring 75 mm in diameter that can be used for interchangeable lenses for cameras and projectors whose size and ...

Recommended for you

Interactive tool lifts veil on the cost of nuclear energy

August 24, 2015

Despite the ever-changing landscape of energy economics, subject to the influence of new technologies and geopolitics, a new tool promises to root discussions about the cost of nuclear energy in hard evidence rather than ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.