Prof. Ian Underwood Profile

Prof. Ian Underwood

Professor and Head of Research Institute at Univ of Edinburgh

SPIE Involvement:

Author

Publications (22)

Proceedings Article | 5 March 2021 Presentation + Paper

A pulse oximeter based on time-of-flight histograms

Yuanyuan Hua, Konstantinos Bantounos, Aravind Venugopalan Nair Jalajakumari, Alex Turpin, Ian Underwood, Danial Chitnis

Proceedings Volume 11693, 116930G (2021) https://doi.org/10.1117/12.2577757

KEYWORDS: Oximeters, Tissue optics, Sensors, Field programmable gate arrays, Tissues, Skin, Single photon, Optical components, Manufacturing, Laser sources

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Proceedings Article | 1 March 2013 Paper

A real-space interactive holographic display based on a large-aperture HOE

Javid Khan, Chi Can, Alan Greenaway, Ian Underwood

Proceedings Volume 8644, 86440M (2013) https://doi.org/10.1117/12.2021633

KEYWORDS: Holographic optical elements, Holography, Displays, Holograms, Sensors, Projection systems, 3D image reconstruction, Computer programming, Optical components, Erbium

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Proceedings Article | 5 May 2010 Paper

A low-resolution 3D holographic volumetric display

Javid Khan, Ian Underwood, Alan Greenaway, Mikko Halonen

Proceedings Volume 7723, 77231B (2010) https://doi.org/10.1117/12.858596

KEYWORDS: Holography, Holograms, 3D displays, Volume holography, 3D image processing, 3D image reconstruction, Projection systems, Image segmentation, Multiplexing

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Proceedings Article | 5 December 2006 Paper

Polymer OLED microdisplay technology: pixel design in context

I. Underwood, D. Burns, R. Woodburn

Proceedings Volume 6333, 633306 (2006) https://doi.org/10.1117/12.687178

KEYWORDS: Analog electronics, Organic light emitting diodes, Transistors, Data storage, CMOS technology, Video, Polymers, Digital electronics, Electro optics, Silicon

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Proceedings Article | 10 November 2003 Paper

Light-emitting polymer on CMOS: a new photonic technology?

Ian Underwood, James Gourlay

Proceedings Volume 5181, (2003) https://doi.org/10.1117/12.509839

KEYWORDS: CMOS technology, Polymers, Photonic devices, Optical signal processing, Optoelectronics, Silicon, Active optics, Photonics systems

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Proceedings Article | 10 November 2003 Paper

SPICE modeling of ferroelectric liquid crystal on silicon microdisplays

Stewart Smith, Anthony Walton, Ian Underwood, Christophe Miremont, David Vass, Will Hossack, Martin Birch, Andrew Macartney, Robert Nicol

Proceedings Volume 5181, (2003) https://doi.org/10.1117/12.509466

KEYWORDS: Electro optical modeling, Liquid crystals, Data modeling, Switching, Liquid crystal on silicon, Ferroelectric LCDs, Silicon, Resistors, Electro optics, LCDs

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Proceedings Article | 26 December 2001 Paper

Antiferroelectric liquid crystal on CMOS technology for microdisplays and microphotonics

Ian Underwood, David Vass, M. Newsam, William Hossack, Georg Bodammer, Vidar Nilsen, J. Tom Stevenson, Alan Gundlach, W. Parkes, Jose Oton, Xabier Quintana, L. Chan, P. Bartelous, N. Flannigan, G. Swedenkrans, Claes Waldelof, M. Rampin, Antonio Vindigni

Proceedings Volume 4435, (2001) https://doi.org/10.1117/12.451148

KEYWORDS: Semiconducting wafers, Metals, Liquid crystals, Liquid crystal on silicon, Electrodes, Electro optics, CMOS technology, Switching, Reflectivity, Photomasks

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Proceedings Article | 26 December 2001 Paper

Model fitting of a SPICE equivalent circuit for the design of ferroelectric liquid crystal on silicon devices

Vidar Nilsen, Christophe Miremont, Ian Underwood

Proceedings Volume 4435, (2001) https://doi.org/10.1117/12.451144

KEYWORDS: Electro optical modeling, Liquid crystal on silicon, Data modeling, Liquid crystals, Silicon, Instrument modeling, Ferroelectric LCDs, Statistical modeling, Circuit switching, Device simulation

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Proceedings Article | 28 December 2000 Paper

Alignment of ferroelectric liquid crystals over CMOS-based microdisplay backplanes

Christophe Miremont, Georg Bodammer, David Calton, Ian Underwood

Proceedings Volume 4207, (2000) https://doi.org/10.1117/12.411758

KEYWORDS: Ferroelectric LCDs, Liquid crystal on silicon, Polymers, Electro optics

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Proceedings Article | 21 June 2000 Paper

64x64 smart pixel array for deformable membrane devices

Kris Seunarine, Ian Underwood, Stephen Graham, David Vass, M. Newsam, J. Tom Stevenson, Alan Gundlach, R. Woodburn

Proceedings Volume 3990, (2000) https://doi.org/10.1117/12.388908

KEYWORDS: Transistors, Capacitance, Logic, Electrodes, Switching, Silicon, Switches, Metals, Circuit switching, Digital micromirror devices

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Proceedings Article | 29 September 1999 Paper

Review of the history and technology of micromachined miniature displays using foundry-produced silicon backplanes

Anthony Walton, David Vass, Ian Underwood, Georg Bodammer, David Calton, Kris Seunarine, J. Tom Stevenson, Alan Gundlach

Proceedings Volume 3891, (1999) https://doi.org/10.1117/12.364442

KEYWORDS: Mirrors, Liquid crystals, Chemical mechanical planarization, Aluminum, Spatial light modulators, Polishing, Semiconducting wafers, Silicon, Oxides, LCDs

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Proceedings Article | 2 September 1999 Paper

Manufacture of aluminium micromirror arrays using a dual damascene process

David Calton, Tom Stevenson, Ian Underwood, Alan Gundlach

Proceedings Volume 3878, (1999) https://doi.org/10.1117/12.361288

KEYWORDS: Aluminum, Mirrors, Polishing, Liquid crystals, Semiconducting wafers, Surface finishing, Manufacturing, Dielectrics, Chemical mechanical planarization, Reflectivity

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Proceedings Article | 23 April 1999 Paper

High-voltage resurf DMOS process development using covariance-based response surfaces

Mark Redford, Martin Fallon, Anthony Walton, Z. Shafi, Jim McGinty, Ian Underwood

Proceedings Volume 3742, (1999) https://doi.org/10.1117/12.346231

KEYWORDS: Data modeling, TCAD, Instrument modeling, Computer aided design, Manufacturing, Transistors, 3D modeling, Epitaxy, Process modeling, Computer simulations

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Proceedings Article | 20 April 1998 Paper

Fabrication of spatial light modulator backplanes using damascene processing

Anthony O'Hara, Georg Bodammer, David Vass, Larry McGhee, J. Tom Stevenson, Ian Underwood

Proceedings Volume 3292, (1998) https://doi.org/10.1117/12.305496

KEYWORDS: Mirrors, Spatial light modulators, Metals, Oxides, Semiconducting wafers, Silicon, Polishing, Chemical mechanical planarization, Surface finishing, Optical alignment

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Proceedings Article | 8 May 1997 Paper

Ferroelectric liquid crystal over active silicon technology for displays

David Vass, Ian Underwood, D. Burns, Anthony O'Hara, Iain Rankin, Georg Bodammer, Michael Worboys, Sharon Radcliffe, M. Griffiths

Proceedings Volume 3013, (1997) https://doi.org/10.1117/12.273870

KEYWORDS: LCDs, Binary data, Video, Silicon, Liquid crystal on silicon, Ferroelectric LCDs, Liquid crystals, Modulators, Spatial light modulators, RGB color model

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Proceedings Article | 11 April 1997 Paper

Performance improvement in optical target recognition by range analysis

Mark Begbie, Steven Heddle, Ian Underwood, David Vass

Proceedings Volume 3015, (1997) https://doi.org/10.1117/12.271392

KEYWORDS: Image enhancement, Image processing, Target recognition, Optical correlators, Spatial light modulators, Cameras, Silicon, Liquid crystals, Very large scale integration, Image analysis

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Proceedings Article | 11 March 1996 Paper

Full-color miniature display

Iain Rankin, Ian Underwood, David Vass, Michael Worboys

Proceedings Volume 2651, (1996) https://doi.org/10.1117/12.235358

KEYWORDS: Spatial light modulators, LCDs, Light emitting diodes, Binary data, Liquid crystals, Video, Silicon, Liquid crystal on silicon, Electrodes, Polarizers

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Proceedings Article | 13 September 1995 Paper

Post-processing using microfabrication techniques to improve the optical performance of liquid crystal over silicon backplane spatial light modulators

Anthony O'Hara, Iain Rankin, Mark Begbie, David Vass, D. Burns, Ian Underwood, J. Tom Stevenson

Proceedings Volume 2641, (1995) https://doi.org/10.1117/12.220934

KEYWORDS: Spatial light modulators, Liquid crystals, Mirrors, Metals, Silicon, Surface finishing, Electrodes, Semiconducting wafers, Microfabrication, Polishing

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Liquid crystal (LC) over silicon backplane spatial light modulators (SLMs) have applications in optical processing and as miniature displays. With these devices a LC layer is sandwiched between the silicon backplane and a front cover glass coated with a transparent ITO electrode. The voltage between electrodes on the controlling circuitry and the ITO electrode determines the state of the LC which in turn is used to modulate incident light onto the device. The silicon backplane consists of an array of pixels similar to DRAM or SRAM devices but where each pixel controls the voltage on an electrode. These electrodes must also act as mirrors reflecting the incident light. The silicon backplanes supplied by commercial foundries which work well electrically suffer from having poor optical quality pixel mirrors. These mirrors have inferior surface quality with low flat fill factor resulting in low optical efficiency. Hillocks are also present which cause problems with LC cell construction. We have developed a post-processing procedure based on silicon microfabrication techniques to add another level of metal to commercially fabricated wafers which addresses these problems. To ensure that his new metal layer is deposited onto a very flat substrate the interlevel dielectric is planarized using chemical mechanical polishing. We have developed this technique to produce an optical quality surface with local surface variations of less than 100 angstrom consistently achieved. The deposited aluminium top layer is optimized for best optical performance within the constraints of the electrical characteristics. Pixel mirrors with flat fill factors up to 84% were realized which improved the optical efficiency of the SLM. No hillocks were present on the metal surface presenting the opportunity to fabricate 1 micrometers thick LC cells to fully utilize the potential of ferroelectric LC. We will also report on a n expansion of the post-processing procedure to protect devices based on DRAM memory layout from photo induced charge leakage. The use of microfabrication techniques to construct the LC spacer layer will also be discussed.

Proceedings Article | 13 September 1995 Paper

Fabrication issues for silicon backplane active matrix miniature liquid crystal display

Ian Underwood, D. Burns, I. Rankine, D. Bennett, James Gourlay, Anthony O'Hara, David Vass

Proceedings Volume 2641, (1995) https://doi.org/10.1117/12.220932

KEYWORDS: Silicon, Mirrors, Liquid crystal on silicon, LCDs, Glasses, Liquid crystals, Binary data, Electrodes, Semiconducting wafers, Optical alignment

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We describe a new technology which is appropriate for the production of lightweight, highly compact displays. It is based upon a thin layer of ferroelectric liquid crystal (FLC) on top of, and directly driven by, an active matrix backplane fabricated on single crystal silicon. While devices can be produced using fairly standard techniques, we have developed custon fabrication and packaging techniques, required for optimization of optical quality and performance. We have successfully developed the technology for spatial light modulators for use in applications such as optical correlators and programmable holograms. The FLC is configured in the binary surface stabilized configuration: the CMOS circuits are digital in nature. The device operates in reflection with each pixel having an aluminium pad which acts as a mirror to reflect light and as an electorde to control the state of the overlying FLC. The technology also shows promise as a display technology so we have demonstrated the devices as displays capable of displaying both grey scale and color. We have built FLC devices upon commercially fabricated wafers but have found it advantageous to carry out custom post processing order to improve performance. The main thrust to date has been the use of ECR oxide deposition followed by chemical mechanical polishing to provide an optically flat substrate for mirror deposition. This allows the deposition of flat mirrors which fill almost all of the pixel area; it also allows optimization of the mirror deposition for high optical quality and good FLC alignment. Work is also well advanced on a technique to fill the vias connecting to the mirror layer and on packaging devices to reduce bowing of the silicon and increase the thickness uniformity of the FLC layer. Recent results are demonstrated on LCDs fabricated above two silicon backplanes containing 176 X 176 pixels and 256 X 256 pixels respectively, the former having dynamic signal storage at each pixel, the latter static storage.

Proceedings Article | 10 June 1994 Paper

Miniature display technologies for helmet- and head-mounted displays

Michael Worboys, Suzanne Day, Stephen Foster, Sharon Radcliffe, Keith Mitchell, David Vass, Ian Underwood

Proceedings Volume 2218, (1994) https://doi.org/10.1117/12.177370

KEYWORDS: Display technology, Head-mounted displays, Head, Light emitting diodes, Displays, LCDs, Video, Thin films, Electroluminescent displays, Ferroelectric LCDs

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Proceedings Article | 1 December 1991 Paper

High-performance spatial light modulator

Ian Underwood, David Vass, Richard Sillitto, George Bradford, Norman Fancey, Adil Al-Chalabi, Martin Birch, William Crossland, Adrian Sparks, Steve Latham

Proceedings Volume 1562, (1991) https://doi.org/10.1117/12.50776

KEYWORDS: Spatial light modulators, Liquid crystals, Silicon, Mirrors, Electrodes, Optical signal processing, Polarization, Computing systems, Switching, Ferroelectric LCDs

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Proceedings Article | 1 November 1991 Paper

Fourier processing with binary spatial light modulators

William Hossack, David Vass, Ian Underwood

Proceedings Volume 1564, (1991) https://doi.org/10.1117/12.49754

KEYWORDS: Spatial light modulators, Holograms, Binary data, Optical filters, Fourier transforms, Liquid crystals, Holography, Optical signal processing, Mirrors, Silicon

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Showing 5 of 22 publications

Conference Committee Involvement (5)

Advanced Free-Space Optical Communication Techniques and Applications

11 September 2017 | Warsaw, Poland

Advanced Free-Space Optical Communication Techniques and Applications

26 September 2016 | Edinburgh, United Kingdom

Advanced Free-Space Optical Communication Techniques and Applications

24 September 2015 | Toulouse, France

Wave Optics and Photonic Devices for Optical Information Processing II

7 August 2003 | San Diego, California, United States

Wave Optics and VLSI Photonic Devices for Information Processing

3 August 2001 | San Diego, CA, United States

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