Reflective Silicon surfaces for display devices
|Organization:||National University of Singapore, Singapore, SG|
|I.P. Brief:||This invention (IP) enables use of porous silicon wafers as reflective surfaces in display devices. It uses ion beam irradiation and materials processing. The invention provides enhanced control over the formation of optical microcavities and Distributed Bragg Reflectors in porous silicon. The precise control over the generation, reflection and transmission of visible and infra-red light could be obtained in “all dimensions” (i.e. 1st, 2nd and 3rd).
This invention also represents a significant advancement in production of silicon lasers.
|Summary of I.P.:||This invention solves problems associated with patterning silicon wafers, glass or other reflective materials. Advancing over the state of the art- ‘centi-meter scale patterning’, the invention enables patterning of silicon wafers on ‘micrometer lateral scale’ to reflect or transmit different colours.
Surface patterning is a critical operation while producing small reflecting surfaces. The reflecting surfaces can be used in projectors based on LCOS (Liquid Crystal On Silicon) technology, rear projection televisions, projection microdisplays, near to eye-microdisplays and other reflective display devices.
In another aspect, the invention enables the fabrication of 2 & 3 dimensional optical
microcavities,thereby providing control of light in all dimensions. This greatly advances the state of the art in production of silicon lasers. For Infra-red wavelengths, this invention will mean that silicon wafers can be patterned with dense arrays of micron-size areas which can be tuned to emit a particular wavelength, for multiplexing applications.
This technology will be of interest to companies that use reflective display technology. The invention would also be of interest to the high tech companies in the field of optoelectronics, silicon photonics, LCOS technology and silicon lasers.
|Patent:||1. PCT/SG2005/00140 and 2. US provisional filed Feb 06 (awaiting particulars)|
|Keywords:||Display devices, rear projection television, data projectors, LCOS technology, Silicon lasers. Optoelectronics, Silicon Photonics|
|Specific Market:||Data Projectors, Rear projection television, micro-displays|
|Market Size:||World market for display devices - USD 61 Billion
Flat pannel display device - USD 35 Billion
Exact market for reflective surfaces - could not be determined.|
|State of the Art:||Display devices based on LCOS chips are expensive due to high costs involved in patterning of reflective surfaces. Current technology requires three separate LCOS displays (for three basic colors). This invention due to micrometer patterning will lead to simpler & cheap projectors using a single LCOS display device.|
|Competition:||OLED (organic light emitting diode) based displays |
|Figures of Merit:||- Reflective surfaces can be made cheaply and in large volumes using existing fabrication technologies and equipment.
- New and non-intuitive technology. |
|Tech. Obstacles:||- Optimization for achieving narrow bandwidth of wavelengths of transmitted and reflected light is ongoing.
- scaling up |
|Market Obstacles:||- Fabrication costs per device needs to be brought down to make commercial production feasible.
- Ion implantation can be expensive for long periods but each device needs only a few seconds of implanter
time. Accordingly, many devices can be prepared at low cost when conditions are optimised (per unit costs shall go down after a crossing threshold.)
|Patent Landscape:|| United States Patent 6,814,849, Lockwood , et al. November 9, 2004, Luminescence stabilization of anodically oxidized porous silicon layers
 United States Patent 6,815,162, Boukherroub , et al. November 9, 2004, Passivation of porous semiconductors
 United States Patent 6,456,416, Ichimura , et al. September 24, 2002, Process and device for producing photonic crystal, and optical element
 United States Patent 6,518,603, Schmuki et al. February 11, 2003, Selective electrochemical process for creating semiconductor nano- and micro-patterns
 United States Patent 6,284,671, Schmuki et al. September 4, 2001, Selective electrochemical process for creating semiconductor nano-and micro-patterns
 United States Patent 5,420,049, Russell et al. May 30, 1995, Method of controlling photoemission from porous silicon using ion implantation
|Publications:|| L. T. Canham, Appl. Phys. Lett. 57, 1046 (1990).
. L. Pavesi, Riv. Nuovo Cimento 20, 1 (1997).
 M. Cazzanelli and L. Pavesi, Phys. Rev. B 56,
 S. Chan and P. M. Fauchet, Appl. Phys. Lett.
75, 274 (1999).
. E.J. Teo, M.B.H. Breese et. al. Advanced
Materials 18 51 (2006)
|Research Team:||1. Prof. Mark Breese
2. Dr. Dharmalingam Mangaiyarkarasi
- combined research experience > 15 years
- Well established research group in NUS
- Strong publications record of related technologies
- Continued research going on