Transcript G.eng.cam.ac.uk - University of Cambridge

H.J. Coles, T.D. Wilkinson
C. Dobson, S. Findeisen-Tandel, D. Gardiner, C. Gillespie, O. Hadeler,
P. Hands, Q. Malik, S. Morris, J. Schmidtke, P-L. Neo, + 11 PhD Research Students
Research at CMMPE
Liquid crystals for displays
CMMPE was officially opened in 2003 by Lord
Sainsbury of Turville. It is an 'embedded'
research centre in the Centre for Advanced
Photonics and Electronics (CAPE). Based in
the Electrical Engineering Division on the West
Cambridge Site, it is one of three parallel
photonics research groups.
Our research themes in the field of flat-panel liquid crystal displays
encompass a range of different electro-optic effects that are suitable for
applications including fast-switching, video frame-rate liquid crystal displays,
and large area, low-power consumption, displays. The work programs can be
categorised into the following headings:
CMMPE combines research scientists from a
number of different disciplines including organic
chemistry, physics and engineering. This enables
fundamental research to be carried out in the
design and synthesis of organic materials for the
next generation of photonic and electronic
applications. Our research areas include:
• Liquid
Liquid crystal
crystallasers
lasers
- Blue phases
- Flexoelectro-optic effect
- Ferroelectrics
- Antiferroelectrics
- Smectic A
- PDLCs
- Hybrid devices
- Dye guest-host systems
• Liquid
Liquid crystals
crystalsfor
fortelecoms
telecoms
Above – Electroluminescent hybrid liquid
crystal plastic display designed for Pelikon
(a) Low light (EL), (b) direct sunlight (LC).
• 2D & 3D holographic
holographicprojection
projection • Optical
Optical pattern
patternrecognition
recognition
• Liquid
Liquid crystals
crystalsfor
fordisplays
displays
• Flexoelectro-optic
Flexoelectro-optic effect
effect
• Electrical
Electrical &&optical
optical
characterisation ofofdielectrics
characterisation
dielectrics
• Hybrid
Hybrid liquid
liquidcrystal
crystalcarbon
carbon
nanotube devices
nanotube
devices
Left – Liquid crystal blue phases are selfassembled 3D cubic defect structures, with
lattice periods of the order of the
wavelength of visible light.
• Adaptive
Adaptive optics
opticsfor
forophthalmic
ophthalmic
imaging
imaging
• Non-linear
Non-linear optics
optics
Adaptive phase modulation devices
Chiral nematic technology
CMMPE is developing new adaptive devices that
CMMPE is developing new adaptive devices that
dynamically manipulate of the phase of light,
dynamically manipulate of the phase of light,
often using liquid crystals.
Examples and
often using liquid crystals.
Examples and
applications of such devices include:
applications of such devices include:
- 2D & 3D computer generated holography
- 2D & 3D computer generated holography
Left - a computer generated hologram is used to
(left - a computer generated hologram is used to
display a video of a clock face.
display a video of a clock face).
- Adaptive optics for ophthalmic imaging
- Adaptive optics for ophthalmic imaging
- Optical pattern recognition (comparators)
- Optical pattern recognition (comparators)
Hybridliquid
liquid crystal carbon
- -Hybrid
carbon nanotube
nanotube
devices
(rightdevices
– a sparse array of vertically
aligned
carbon
nanotubes
are
grown
on
a
Right – a sparse array of vertically aligned
substrate
and used are
to electrically
carbon nanotubes
grown on aaddress
substratea
nematic
liquid
crystal, generating
and used
to electrically
address aaGaussian
nematic
electric
field,
and
a
switchable
optical
device,
liquid crystal, generating a Gaussian electric
similar
an adaptive
microlens
array).device,
field, toand
a switchable
optical
CMMPE has been developing a whole
host of new devices based on chiral
nematic liquid crystals. There are several
different structures that can be used
including the standing helix which forms
a periodic refractive index or photonic
bandgap. Typical applications:
- Liquid crystal lasers
- Liquid crystal telecoms components
Above - chiral nematic can also be
- Polarisation controllers
used in the uniform lying helix
mode which allows devices which
can perform colour switching
(below) and multi-level phase
modulation.
Above - the helix pitch can be tuned by
applied field, temperature, frequency
and physical deformation to give a
tuneable band gap.
similar to an adaptive microlens array.
www-g.eng.cam.ac.uk/CMMPE