MEMS – small is beautiful

Citation

Loughlin, C. (2002), "MEMS – small is beautiful", Sensor Review, Vol. 22 No. 1. https://doi.org/10.1108/sr.2002.08722aaa.001

MEMS – small is beautiful

MEMS – small is beautiful

Our theme for this issue is Micro Electromechanical Sensors / Systems (MEMS). MEMS technology is fascinating for many reasons, but the one that most appeals to me is that it encompasses such a wide variety of engineering disciplines. Mechanical design, semiconductor and materials technology, sensors and electronics all combine as pieces of the jigsaw that makes up MEMS.

In the past many industrial or laboratory systems will have been composed of several parts including actuation mechanisms, sensors, signal processors and recorders; together with a tangled web of interconnecting cables and perhaps the odd computer or two tagged on to monitor or control the process. All very well, but these systems take up a lot of bench space, are expensive and are made less reliable by the cables that connect them and the overall complexity of the system. Their physical size also restricts the applications in which they can be deployed and the time constants of the readings that are being taken.

Semiconductor technology has revolutionised electronic control and computer systems and the main reason for the revolution has been the ever reducing size of the semiconductor structures that can be fabricated, which in turn has lead to tremendous improvements in processing speed and also in the number of devices that can be incorporated onto a single chip. This in turn has reduced the number of chips required and the interconnections between them which results in greatly improved reliability.

MEMS use the same basic fabrication techniques that have been applied so successfully to semiconductors and add in the ability to form physical structures that move.

As a general rule engineers associate a reduction in the number of moving parts with an improvement in reliability and zero moving parts as a worthwhile goal. Watches are a good example. However there are times when you simply have to make a physical movement.

I have recently attended an Institute of Physics National Measurement Conference, and a lot of the sessions that I attended concerned surface roughness measurement. Some people use optical sensors while the majority still use stylus based instruments. The conclusion that I came to was that the optical systems provide a measure of surface roughness but it bears little resemblance to results of those in the stylus camp. The main difference of course is that the stylus group measure the physical contours as part of a 2D scan across the surface while the optical group measure the appearance of a 2D or 3D section of the surface. Both have severe limitations and are subject to wide variations in the data obtained.

Apply MEMS technology to surface roughness measurement and you should end up with a pocket sized device capable of a detailed 3D surface scan and of providing repeatable measurements. All at a fraction of the cost of present systems.

This is just one very obvious example of the opportunities that are being opened up by this exciting new technology. These are early days, but the future for MEMS and sensor development is looking very bright indeed.

Jack Hollingum

It is with great sadness that I report the death of Jack Hollingum at the age of 76 following a succession of heart problems (Plate 1). Jack was one of the founding editors of Sensor Review as well as our sister journals Assembly Automation and Industrial Robot.Over the years he has written countless articles and has remained a regular contributor right up to having a stroke in April 2001.

Plate 1

He started his engineering career with the aircraft manufacturer Vickers Armstrong Weybridge, before turning his hand to engineering journalism and working for many prestigious publications including Metalworking Production and The Engineer. He was also the author of several books spanning topics as diverse as smart cards and machine vision.

Engineers are people who aim to make things better, and an engineering journalist aims to give them the knowledge and information to make this possible by reporting on up-and-coming research and working systems. The secret is to make articles interesting and informative and of practical benefit to those who read them. Giving other engineers ideas that they can use in their own systems, and warning them of problems and how they can be overcome.

Jack was a master of the art, and managed to ask incisive questions with great courtesy and charm. He also had a boundless enthusiasm for all things technical and led the way in the adoption of the new technology that we now all take for granted.

Prolific as he was as an engineering journalist, Jack was also a devout Christian and devoted a lot of his time and energy to the ecumenical Church. This work included two years as the full time Industrial Secretary of the Student Christian Movement. He was a devoted family man and leaves a wife and three sons.

In recognition of his contribution to this journal the annual Literati award for the most Outstanding Paper will be known as the Jack Hollingum Award.

I will greatly miss his contributions to the journal and the support of a colleague and much admired friend.

Clive Loughlin