doc.: IEEE 15-12-0638-00-0led
November 2012
Project: IEEE 802.15 LED(Light Emitting Diode) Interest Group (IG-LED)
Submission Title: [Organic Visible Light Communications]
Date Submitted: [November, 2012]
Source: [Hoa Le Minh, Zabih Ghassemlooy, Andrew Burton, Paul Haigh]
[Northumbria University]
Address [Northumbria University, Newcastle upon Tyne, UK]
Voice:[44-191-227-3901], FAX: [44-191-243-7630], E-Mail:[[email protected]]
Re: []
Abstract: [OLED-based VLC]
Purpose: [Contribution to IEEE 802.15.4a]
Notice: This document has been prepared to assist the IEEE P802.15.4a. It is offered as a basis for
discussion and is not binding on the contributing individual(s) or organization(s). The material
in this document is subject to change in form and content after further study. The contributor(s)
reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE
and may be made publicly available by P802.15.4a
Submission
Slide 1
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
Contents
• Visible light communications
• Organic light emitting diode (OLED)
• OLED-based VLC
• Challenges and possibilities discussion
Submission
Slide 2
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
General Lighting Sources
Incandescent bulb
First industrial light source
5% warm light, 95% heat
Few thousand hours of life
Fluorescent lamp
White light, cheap
25% light
Lifetime ~10,000s hours
Solid-state light emitting diode (LED)
Compact, cheap, powerful
50% light
More than 50,000 hours lifespan
Organic light emitting diode (OLED)
Flexible and bendable panel
Extensively used in high-end display products,
HDTV and Smartphone
Submission
Slide 3
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
Lighting Emitting Sources
RGB
-
-
Well-known technology
Limited use due to difficulties in
RGB balancing
Phasing out in lighting industry
Submission
Blue chip + Phosphor
-
Popular for today general lighting
industry
Standardised for illumination and
visible light communications
Slide 4
OLED
-
Emerging technology
Early stage of development
High potentials for VLC
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
OLED Lighting Performance
Efficiency
-100% internal quantum efficiency (Fraunhofer IPMS – COMEDD, 2012)
-Brightness 2.000 cd/m², 5mm thickness (Verbatim Velve, 2012)
-120 lumen (~table lamp) (Philip Lumiblade GL350, 2012)
-80 lumen/watt with 20.000 hours of lifetime (LG, 2012)
Submission
Slide 5
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
OLED Applications
- Dominant in high end Smartphone display products: Super-AMOLED)
(Samsung Galaxy S3 phone, 2012)
- 55 inch OLED HDTV (Samsung Electronics, 2012)
- 6 inch E-paper on plastic (XGA, 14 gram, 0.7mm thickness), (LG, 2012)
- Solar OLED car (BASF, 2012)
- Flexible AMOLED display (Samsung patent, 2012)
Submission
Slide 6
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
OLED Modulation Bandwidth
0
Response (dB)
-2
-4
-6
-8
-10
-12
200
400
600
Frequency (kHz)
800
1000
Measured frequency response of
(Philips) Lumiblade white OLED
Measured frequency response of
(Philips) Luxeon-star white LED
OLED BW is much narrower than LED!
Submission
Slide 7
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
OLED Structure
Typical structure:
1. Glass (filled with inert gas to protect other
layers)
2. Anode/Hole transport layer (HTL)
3. Organic emitting layers (to control emissi
ve colours)
Including organic compounds
4. Electron transport layer (ETL)
5. Cathode (typically indium tin oxide (ITO)
)
Thin film technology:
OLED layers ~1-200 nm
Submission
Slide 8
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
Electrical Characterisation
For lighting
Large panel  better for illumination
 larger capacitor value
Rp - electrode contact resistance
Rd - diode resistance
C - diode capacitance
Submission
For communications
Larger capacitor value  slow response
Slide 9
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
Equalisation
First order equaliser experimental test-bed
-
Simple implementation
1st order response (linear)
Cost effective
H. Le-Minh, D. C. O'Brien, G. Faulkner, L. Zeng, K. Lee, D. Jung and Y. Oh, "100-Mbit/s NRZ Visible Light Communications Using
a Post-Equalized White LED", IEEE Photonics Technology Letters, vol. 21, no. 15, pp. 1063-1065, 2009
Submission
Slide 10
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
OLED BW Improvement
Philip Lumiblade OLED
Measured frequency response corresponding
to different equalisers
H. Le Minh, Z. Ghassemlooy, A. Burton and P. A. Haigh, "Equalization for Organic Light Emitting Diodes in Visible Light Communications
" IEEE GLOBECOM, Workshop on Optical Wireless Communications in Houston, USA, 5-9 December, 2011
Submission
Slide 11
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
Decision Feedback Equalizer for OLEDVLC Links
Osram Orbeos OLED
-
DFE: widely used in digital systems transmitting through BW-limited AWGN channels
Better performance than ZF and MMSE-based filter
DFE
Submission
Slide 12
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
OLED OFDM VLC
1 Mbit/s
3 Mbit/s
5 Mbit/s, BER < 10-5
A. Burton, P. A. Haigh, H. Le Minh, Z. Ghassemlooy, S. Rajbhandari and S. K. Liaw, "A Comparative Investigation Study of Modulation and Equalization
Techniques for White-Light Emitting Organic Light Emitting Diodes Using in Visible Light Communications", IEEE Communications Magazine, 2012 (sub
mitted)
P. A. Haigh, Z. Ghassemlooy, H. Le-Minh, S. Rajbhandari, F. Arca, S. F. Tedde, O. Hayden and I. Papakonstantinou, "Exploiting Equalization Technique
s for Improving Data Rates in Organic Optoelectronic Devices for Visible Light Communications", IEEE Journal of Lightwave Technology, 2012
Submission
Slide 13
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
Challenges
• OLED is under development, therefore challenges are widely expected from
-
Materials and device structures are being evolved and varied from different manufacturers
Heavily calibrated for display purpose (unlike LED used for signalling and illumination)
In the early stage of lighting and decoration utilisation (@2012)
Expensive (~10/20 times costlier than the same performing LED)
Lack of wide range of commercially available products
• Communications aspects
-
Light efficiency is low  large illumination panels are typically fabricated  high
capacitance thus limiting the device modulation bandwidth (100’s kHz)
Limited researches in data communications
Not yet being standardised
Submission
Slide 14
Northumbria University
doc.: IEEE 15-12-0638-00-0led
November 2012
Possibility and Potentials
• Possibilities and Future Work
-
-
Achieving higher data rate, such as 10-15 Mbit/s, so that OLED can be adopted in standard
10BASE-T Ethernet communications
Working with the manufacturers to improve the device response time (newer display has
faster response and wider dynamic contrast range)
Device modelling and characterisation to optimise the performance
Possible to adopt the existing VLC standard (IEEE 802.15)
• Potentials and Opportunity
-
OLED is increasingly available in many displays, tablets and phones  new areas of shortrange and personal VLC applications and researches
Toward mobile and flexible VLC
Submission
Slide 15
Northumbria University