Microlens part I - Introduction

Warning: It's a technical post

In my article, “what are POEMS, technically?” I discussed about the different emerging fields (some of them are already commercially viable) based on the miniaturization of the various mechanical, electronic and optical component, along with the changes in approach in terms of processes, techniques and materials. Albeit superficially we mange to get some idea about the vast (but very small) fields of MEMS, MOEMS and POEMS.

Today I will try to enlighten you about microlens, which can be considered as one of the most important components in the field of microoptics.

Starting with the definition: Simply speaking microlens is a lens whose geometrical size or aperture is less than 1 mm. So, most of the time when we say microlens, we mean lens which is small...smaller than the conventional lens. That’s that for the time being. I will introduce complexities in the definition later.

Having understood about the basic defining criteria for a lens to be known as microlens, let me throw some light on how it all started. I mean the background: Conventional lenses have been an area of interest for long. Even in the mid of 17th century, geniuses like Robert Hooke had already produced their own lenses. However, it was not until the arrival of fiber optics that brought with itself the trend of miniaturization for optical components. The important fabrication techniques, nevertheless, were still based on classical way of grinding and polishing. More recently (1970s), the development of IC fabrication techniques and its adaptation in the field of optics, has helped the idea of miniaturization to be realised, which in turn helped to generate optical components in the micrometer range.

The synergy of fiber optics with IC fabrication techniques, along with their potential applications, produced the basic thrust that lead to idea of producing smaller dimension optical components, (microlens being most important of them).