Electric Potential Sensor Technology – From Fundamental Physics to Product
Submitting InstitutionUniversity of Sussex
Unit of AssessmentPhysics
Summary Impact TypeTechnological
Research Subject Area(s)
Engineering: Electrical and Electronic Engineering
Medical and Health Sciences: Neurosciences
Summary of the impact
A ground-breaking range of innovative sensor products — the EPIC Sensors
— has been developed and marketed world-wide by Plessey Semiconductors
Ltd. The EPIC Sensors allow contact-free measurements of electric
phenomena, initially aimed at the health, sports and automotive markets.
They operate on the non-invasive, low-cost, generic, award-winning
Electric Potential Sensor (EPS) technology invented and developed at
Sussex as a spin-off from fundamental low-temperature physics research.
Income to the University from licence fees, costs and royalties started
during 2012. Sustained industry engagement with key strategic partners in
the medical, forensic, security, materials testing and geophysics sectors,
including government organisations, industry and academia, is leading to a
wider awareness and adoption of this novel technology.
Electric Potential (EP) Sensor Technology was originally conceived as
part of a fundamental low-temperature quantum circuit physics research
project funded by EPSRC (GR/J35146/01, 1993-96, £232k; GR/K15565/01,
1994-97, £110k). The focus of this activity was to study, both
theoretically and experimentally, the behaviour of SQUID systems as simple
macroscopic quantum objects, akin to single atoms [see Section 3, R1].
Probing the energy-level structure and investing the conjugate flux and
charge behaviour in a non-invasive, adiabatic manner involved the use of
extremely sophisticated low-noise experimental techniques. Specialised
shielded rooms and ultra-low noise temperature electronics were
specifically developed for this project [R2]. As part of this programme of
instrumentation development, a cryogenic electrometer was developed with
extremely high input impedance and commensurately low input capacitance to
enable the charge on the quantum system to be measured accurately. From
the start it was apparent that this was a device with generic sensing
capability quite unlike anything that had existed before. Initial funding
for the sensor, as an independent research activity, was provided by two
EPSRC awards (GR/H57516/01, 1993-94, £80k; GR/K38021/01, 1995-97, £81k).
During this period the programme of fundamental physics research continued
in parallel with the development of the sensor. This separate funding
stream enabled research on the fundamentals of measurement at extreme
impedances to be undertaken and for the measurement capability to be
demonstrated in a range of different scenarios. The results of this work
were to show that the sensor could operate using very small displacement
currents (~10-15 A), through weak (<10-15 F)
capacitive coupling over a broad range of frequencies from quasi-DC
upwards [R3]. Additionally, the results revealed that this sensor could be
used as the basis for a novel imaging microscope system [R4] which was not
restricted to working within the tunnelling distance of the surface of the
sample. Initial work on larger-scale electrode structures also yielded
interesting results when applied to electro-physiological measurements.
Conventionally these would use low impedance wet-gel electrodes. By
adapting the EP sensor to operate through a larger (>10-12
F) coupling capacitance, it was possible to demonstrate low-noise
electrocardiogram signal acquisition without the need for gel or resistive
contact with the skin, so simplifying the procedure considerably [R5]. It
is intrinsically stable, electrically and mechanically robust, and
chemically and biochemically inert.
This work was followed by an RCUK Basic Technology award (GR/R87550/01,
2002-06, £1.1m) where the sensors were configured to measure either
electric field, spatial potential or static charge, either through weak
capacitive coupling or in free space. During this period, extensive
research led to significant publications — including [R6], which won the
IOP Measurement Science and Technology `Best Paper Award' (2002) — and to
the first of a suite of seven patents filed. A number of these are now
granted worldwide (EP1451595, US7885700, JP4391823, TWI308066, EP2002273,
AU2007228660, US8264247, US8054061, CN101490564, EP2047284, US12/278214,
JP2008552874), with the rest in process. In addition, there were 25 other
journal publications relating to EP sensors in this period. Continued
funding from the EPSRC (Translation grant EP/E042864/1, 2007-11, £893k)
and industry (£1m) has since enabled a broad range of projects to be
undertaken spanning a wide range of possible future application areas
which clearly demonstrate the disruptive potential of the technology.
These include electrophysiological sensing [R5,R6], movement detection and
tracking, human machine interfacing, NMR instrumentation, materials
characterisation [R3,R4], surface-charge imaging for forensic
fingerprinting, and stress monitoring for geophysical applications and
structural-health monitoring. At this stage it became clear that
applications could span all length scales, ranging from f06dm to metres,
with corresponding levels of spatial resolution, and sensors could also be
integrated into one- or two-dimensional imaging arrays.
References to the research
R1 Prance, H., Prance, R.J., Clark, T.D., Spiller, T.P. and
Clippingdale, A.J. (1993) `Probing the nonlinear electric susceptibility
of ultra-small capacitance weak links', Physics Letters A, 181(3):
R2 Whiteman, R., Schollmann, V., Everitt, M., Clark, T.D., Prance,
R.J., Prance, H., Diggins, J., Buckling, G. and Ralph, J.F. (1998)
`Adiabatic modulation of a SQUID ring by an electromagnetic field', Journal
of Physics: Condensed Matter, 10(44): 9951-9968.
R3 Clippingdale, A.J., Prance, R.J., Clark, T.D. and Brouers, F.
(1994) `Non-invasive dielectric measurements with the Scanning Potential
Microscope', Journal of Physics D: Applied Physics, 27(11):
R4 Prance, R.J., Clark, T.D., Prance, H. and Clippingdale, A.
(1998) `Non-contact VLSI imaging using a scanning electric potential
microscope', Measurement Science and Technology, 9(8): 1229-1235.
R5 Clippingdale, A.J., Prance, R.J., Clark, T.D. and Watkins, C.
(1994) `Ultrahigh impedance capacitively coupled heart imaging array',
Revue of Scientific Instruments, 65: 269-270.
R6 Harland, C.J., Clark, T.D. and Prance, R.J. (2002) `Electric
potential probes: new directions in the remote sensing of the human body',
Measurement Science and Technology, 13(2): 163-169.
Outputs R2, R3, R6 best indicate the quality of the underpinning
Outputs can be supplied by the University on request.
Details of the impact
Following directly from the outputs of the fundamental research programme
above, a generic version of the EP sensor system was showcased at a
`Position Sensitive Detectors in Physics' meeting organised by the
Research Instrumentation Special Interest Group (RSIG), held in London in
May 2010. The event was intended to facilitate interaction between the
high-energy physics, security and medical sectors. As a direct result of
this, a dialogue with Plessey Semiconductors began which culminated in an
exclusive manufacturing licence, signed in December 2010. By September
2011, the first integrated-circuit version of the sensor had been
successfully implemented by Plessey and was ready for designing into
products. A second sales licence was agreed with Plessey in June 2012. The
technology is now being marketed as the Electric Potential Integrated
Circuit (EPIC) sensor [see Section 5, C1].
The main impact of this sensor technology to date has been on Plessey
Semiconductors [C1]. Following a restructuring of the company, two new
technologies were acquired from UK universities, with the specific aim of
transforming the company from a foundry manufacturer of semiconductor
components to a product-oriented company focused around two major product
lines. EP sensor technology from Sussex is one of these two and has had a
significant impact on both the shape and the direction of the company.
Plessey has made a major investment and commitment to EP sensors. The
current levels of investment within Plessey stand at £x, with x employees
dedicated full-time to the technology, in applications support, sales and
marketing, and development through funded collaborative programmes.
Revenue to the University of Sussex from the licences is a mixture of
licence fees (£x for 11/12), patent costs and royalty payments, which
started in 2013. Royalties are based on sales of £x for 2012 and projected
sales of £x for 2013 and £x for 2014.
In addition to this overt commercialisation of the technology, work has
been carried out in conjunction with the Research and Enterprise Division
and the Innovation Centre (SInC) at Sussex, with funding from the
Enterprise Panel (University of Sussex) and the South East Health
Technologies Alliance (SEHTA) to develop awareness of the technology in
the wider community. EP sensors have been judged to be disruptive in a
number of market sectors, by both a multi-national company [C10] and
independent consultants [C11]. There was therefore a perceived need to
engage with and educate the market and potential users about the
capabilities of this new disruptive technology. Necessarily, due to the
generic nature of the sensors, this involved a diverse range of
institutions and companies across a broad spectrum of market sectors. The
model used for this engagement process was to issue evaluation licences to
organisations for a 12-month period with a small fee to cover costs and
the requirement of a confidential written report at the termination of the
licence. The funding enabled a batch of pre-production prototypes to be
manufactured by a local SME (Interface2 Ltd, Newhaven) [C2], for
distribution under these evaluation licences to interested commercial
organisations (from multi-nationals to SMEs, both within the UK and
outside) and to potential partners (including universities, government
laboratories and organisations). To date the University has placed 20
evaluation licences and has direct involvement with collaborative projects
across all market sectors, including healthcare, sports, security[C4],
safety, aerospace [C3], automotive and geophysics [C6].
In partnership with a number of commercial organisations,
proof-of-concept designs were developed spanning electrophysiological
measurement, with Plessey funding 3 postdoctoral positions at Sussex;
Rescon Ltd, two DARPA contracts — £150k; a multi-partner EU grant with
Philips Healthcare and Plessey (2012-16, >£20m); surface-charge density
imaging, including forensic fingerprinting, in collaboration with the Home
Office/CAST [C4]; movement sensing, MOD funded, 2009-10, £98k; aerospace
instrumentation, TSB-funded project `Novel Electric Field Sensors for
Advanced Aero-Engine Monitoring' with Meggitt Sensing Systems [C3] and
Plessey Semiconductors [C1], 2012-14, total £1.1m, £524k industry; and
geophysical and structural health monitoring with British Geological
Survey, Keyworth [C5].
The additional impact directly resulting from this engagement activity
- Interface2, a local SME, is now the main sub-contractor for a much
larger organisation, Plessey, with responsibility for building the EPIC
chip into a variety of products [C1] for them.
- The evaluation licensees are in direct contact with Plessey either as
customers or as potential customers for Plessey products.
- Market sectors identified by evaluation licences form the major market
sectors for Plessey (Automotive, Sports, Healthcare).
- The pre-production prototype design was adopted directly by Plessey as
their first commercial demonstration unit and manufactured by
- One postgraduate student was funded by and seconded to Plessey as a
postdoc. x Plessey employees work directly on EPIC-related projects and
EP sensor technology has received external recognition for both the research
contribution and the commercialisation activity, including awards at
international trade fairs and product reviews:
- EPSRC, Basic Technology Review Panel Report [C6] (2010)
- RCUK, `Big Ideas for the Future' [C6] (2011)
- IET Innovation Award 2011, `Measurement in Action' [C7]
- Gold award at `Best of Sensors Expo 2011' [C8]
- EDN `Hot 100 products' list [C9] (2011): `The most innovative and
significant products and technologies as selected by the editors',
250,000 website viewings per month
- Finalist for Times Higher Innovation Award 2011
- Shortlisted for Army Research Office award 2012
- (2008) Nature Research Highlights 454(21): 920 (Impact Factor
36.101, estimated readership of 424,000) doi:10.1038/454920b.
New Scientist, 2812: 22, 14 May 2011, estimated readership of
Homeland Security Newswire, 23 May 2011, 30,000 specialist
The Economist, 13 October 2012, Weekly circulation 1.5 million,
In summary, the original basic research has spawned multi-million-pound
investment in developing it into concrete engineering applications,
supported by strategic university elements, giving rise to sustained
impact on industrial sensor solutions that are now starting to generate
substantial world- wide revenue for a UK company. It is clear that this is
an activity with the potential to grow both in magnitude and in the
diversity of its applications.
Sources to corroborate the impact
C1 Technology Director, Plessey Semiconductors:
C2 Sales Manager, Interface2 Ltd.
C3 Research and Technology Manager, Meggitt Sensing Systems.
C4 Research Scientist, Home Office CAST.
C5 Head of Science Land Use, British Geological Survey.
C6 Featured in: `Evaluation of the Basic Technology Programme,
Findings and Recommendations of the Review Panel', EPSRC Theme Day, 19 May
and the RCUK `Big Ideas' report, 2011
C7 Winner of the IET `Measurement in Action' Innovation award 2011
C8 Winner of the Gold Award at the `Best of Sensors Expo', Sensors
Expo, Chicago, 2011
C9 Selected for the EDN `Hot 100 Products' list, 2011 http://www.edn.com/electronics-news/4368490/Plessey-samples-electric-potential-sensor-item-2
C10 Kodak European Research Ltd, Cambridge (No longer trading in
C11 Scientific Generics Ltd, Cambridge (Confidential report by
consultant for University of Sussex)