Custom-Sized Microlenses

Aug 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: Two US agents charged with fraud during Silk Road inquiry

Related Stories

Industry's largest glass-molded aspheric lens

Feb 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 ...

Toshiba Glass shown at Ceatec in Japan

Oct 09, 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.

Recommended for you

Amazon unveils move in local services

2 hours ago

US online giant Amazon said Monday it was launching a services marketplace offering to connect consumers with businesses offering anything from home improvement to piano lessons.

Apple Watch to spark wearable tech growth: IDC

3 hours ago

Wearable technology devices are seeing a growth surge that is likely to continue over the next few years, helped by the soon-to-be-released Apple Watch, a market tracker said Monday.

User comments : 0

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.