Leaps in Technology, and the spin-off

Whilst pacemakers and other implants have become fairly commonplace in medical treatment systems, these still rely on battery technology, and have a limited life. When dealing with electrodes or sensor devices positioned carefully, sometimes deep in the body, a battery capsule is embedded under the skin, to enable future access for replacement. A new development project at MIT, to be more fully described at an August conference, describes a very small medical implant that can be powered and interrogated using radio frequency waves, even though it is deep within the body.

Medical devices that can be ingested or implanted in the body could offer doctors new ways to diagnose, monitor, and treat diseases. In their study, the researchers tested a prototype about the size of a grain of rice, but they anticipate that it could be made smaller. Giovanni Traverso, a research affiliate at MIT’s Koch Institute for Integrative Cancer Research, is now working on a variety of ingestible systems that can be used to deliver drugs, monitor vital signs, and detect movement of the GI tract.

In the brain, implantable electrodes that deliver an electrical current are used for deep brain stimulation, which is often used to treat Parkinson’s disease or epilepsy. Wireless brain implants could also help deliver light to stimulate or inhibit neuron activity through opto-genetics.

In animal tests the researchers have shown that the radio waves can power devices located 10cm deep in tissue from a distance of 1m. Until now, this has been difficult to achieve because radio waves tend to dissipate as they pass through the body. To overcome that, the researchers devised In Vivo Networking (IVN), a system that relies on an array of antennas that emit radio waves of slightly different frequencies. As the radio waves travel, they overlap and combine in different ways. At certain points, where the high points of the waves overlap, they can provide enough energy to power an implanted sensor.

Mobile phone developments

The ubiquitous mobile phone. In various past articles I have mentioned the spin-off effects of the technology behind telecommunications and the mobile phone being used to create new industrial sensors, relying on the research and the production capabilities for the devices required for the industry. These spin-offs include the rise of radar level measurement systems, the use of wireless in many industrial sensors, and also the availability of many laser diodes, used for interferometry, liquid analysis etc.

Another major development is that of the liquid lens, used in these same mobile phones. This gets really personal, as for the last 60 years I have been an avid aero-spotter, keenly watching light aircraft arrive at our local airport using a telescope to identify them. Then, on arrival at or near the airport, using long and heavy telephoto lenses to photograph them. Later, I collected antique telescopes, manufactured from 1780 to maybe 1850, as they were still really the best quality optical systems, despite modern (commercial) developments. Again, long and heavy things.

But along came the liquid lens. This is a very small lens device, now commonly used in iPads and mobile phones. The liquid droplet forming the lens has its shape changed electronically, using an electronic control system. This is able to change focal length (to focus) and change optical axis (for optical image stabilization, ie to reduce camera shake effects) – all within a few milliseconds.

The idea for this invention came from research on the phenomenon known as “Electro-wetting” by Professor Bruno Berge, in Lyon, France, with the original patents being issued in 2002. Prof Berge started working on liquid interfaces from 1991 at the Ecole Normale Supérieure in Lyon. A drop of water affected by electro-wetting can function as a variable magnifying glass: so two clear, non-miscible liquids of the same density, one being electronically controlled water, can serve as a lens, depending on the curvature of the interface between them. The two liquids are sealed and held in a metal casing that is typically smaller than 10mm in diameter.

Berge first approached Canon cameras with the invention, but attracted no funding. So with French state funding, and investment fund backing, Berge founded the company VariOptic in 2002. In 2007 they established a production line in China, and in 2009 the first industrial barcode reader with a VariOptic lens appeared on the market. Machine vision manufacturer Cognex was an early adopter of the technology, for barcode ID readers.

A new module now available from IDS (Imaging Development Systems) is a single board USB interface camera, available for use with and control of liquid lenses. These low-cost uEye LE industrial cameras with twist-proof USB Type-C connection and practical USB power delivery are quoted as interesting for logistics systems (eg for package acceptance and sorting), for microscopy and traffic monitoring, as well as for installation in small medical or industrial devices.

So, I am still waiting for a lightweight long focal length telephoto ‘liquid’ lens for my Canon camera. Maybe not the telescope – for as I pointed out to Prof Berge, one of my favourite telescopes dating from the 1790s was made by Matthew Berge, his namesake!

The full story about the Prof Berge development of liquid lenses was first reported by me as the very first blog post on www.telescopecollector.co.uk, back in December 2013.

This article was first published in the South African journal of Instrumentation and Control issue of August 2018, published by technews.co.za

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