Transcript An Introduction to Optical Displays

Optical Displays Module
Thomas D. Anthopoulos
EXSS Group
Department of Physics and Centre for Plastic Electronics
Imperial College London
London
October 2014
Course Description
Course Description (5 ECTS)
This module will offer an introduction to the field of optical displays, covering the
technologies currently in use and those expected to feature in the next generation of
display technologies. The module will offer a short introduction the different kinds of
optical displays available, and will briefly discuss the current driving forces governing
market trends. The lectures will discuss the way in which the human eye operates and
how it affects the way in which we perceive optical displays. The course will then move
on to cover all of the physical and technical properties associated with understanding
and characterizing optical displays, such as luminous power, luminous efficiencies and
understanding the 1931 CIE colour space standard etc. The lectures will cover the
various technical approaches applied in the manufacture of different optical displays;
the physical structure of the displays as well as their operating principles will be
discussed in detail, including a summary of the main areas we need to address for
future display technologies.
Grading
Activities
Homework
Presentation
Middle Term Exam
Final Exam
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Percentage
20
10
20
50
Aim of the course
Aim
Investigate properties of optical display technologies:
- currently in use
- and those being developed
Thomas D. Anthopoulos
Aim of the course
Aim
Investigate properties of optical display technologies:
- currently in use
- and those being developed
What you will discover
How to quantitatively asses the quality of an optical display
Main problems researchers need to solve for each technology
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Content
• Quantifying important display properties
• Colourimetry and cathode ray tubes
• Non-emissive displays
- Liquid crystals
- Electrophoretic
- Electrochromic
- Micromirrors
• Emissive displays
- Plasma, vacuum fluorescent
- Field emission
- Thin film electroluminescence
- Inorganic LEDs
• Organic LED based displays
• Thin-Film Transistors and circuits
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x
Quantifying important display properties
• Introduction
- What are optical displays used for?
- What drives the displays market?
- What types of display are there?
What are the important properties of an optical display?
How can important display properties be quantified?
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What are optical displays used for?
Four main applications:
• Computer monitors
• TVs
• Mobile Phones / iPads etc.
• Notebook, PCs etc.
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What are optical displays used for?
Four main applications:
• Computer monitors
• TVs
• Mobile Phones / iPads etc.
• Notebook, PCs etc.
Also:
Entertainment
Projection TVs
Home appliances
(DVD, video and Hi Fi)
Games / toys
Portable
Watches
Phones
Digital cameras
Camcorders
E-readers
PDAs
Interfaces
Instrument panels
(cars, planes, trains)
Industrial machines
Medical imaging
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Information
Advertising
Cash machines
Shop and transport signs
Point of sales
Education
Future
Smart cards
Wearable displays
Many more…..
What drives the displays market?
One of largest technology markets, and growing rapidly….
Size of market: >>$100 billion
Trends:
• Increasing share of flat panel displays
- Flat panels have the vast majority of the market
• Flat panel display market dominated by LCDs
• Many technologies co-exist
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What drives the displays market?
Why is displays market growing?
• Initially: Desire to replace bulky cathode ray tubes (CRT)
• Currently: Increase in number of portable devices (phones, PDA etc) with
displays
- Display size, weight, ruggedness and battery life
• Information explosion!
- Mobile internet etc
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What types of display are out there?
Cathode Ray Tube
Flat Panel
Displays
Emissive
Non-emissive
Liquid
Crystal
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Liquid crystal displays
How can these be improved?
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X
A
Y
Electrophoretic displays
Transparent
fluid
+ + +
+ ++ + +
- - -- -- - Negatively charged
black pigment chips
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Positively charged
white pigment chips
Electrophoretic displays
Transparent
fluid
+ + +
+ ++ + +
Positively charged
white pigment chips
Newspaper
- - -- -- - Negatively charged
black pigment chips
Electrophoretic display
with extremely low
power consumption
Could these really replace paper?
(e-ink)
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What types of display are out there?
Cathode Ray Tube
Flat Panel
Displays
Emissive
Non-emissive
Liquid
Crystal
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Electrophoretic
Electrochromic
Micromirror
What types of display are out there?
Cathode Ray Tube
Flat Panel
Displays
Emissive
Non-emissive
Liquid
Crystal
Plasma
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Electrophoretic
Electrochromic
Micromirror
What types of display are out there?
Cathode Ray Tube
Flat Panel
Displays
Emissive
Non-emissive
Liquid
Crystal
Plasma
Vacuum
fluorescent
Field
emission
Electrophoretic
Electroluminescence
Inorganic
Thin film EL
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Inorganic LEDs
Electrochromic
Micromirror
Thin film electroluminescent displays
Electrodes
~200 mm
Electrodes
(Pelikon)
Thin film phosphor /
ceramic laminate
Can higher brightnesses be achieved?
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Display, driver and power supply
all thin enough to fit inside credit
card!
What types of display are out there?
Cathode Ray Tube
Flat Panel
Displays
Emissive
Non-emissive
Liquid
Crystal
Plasma
Vacuum
fluorescent
Field
emission
Electrophoretic
Electroluminescence
Inorganic
Thin film EL
Thomas D. Anthopoulos
Inorganic LEDs
Electrochromic
Micromirror
What types of display are out there?
Cathode Ray Tube
Flat Panel
Displays
Emissive
Non-emissive
Liquid
Crystal
Plasma
Vacuum
fluorescent
Field
emission
Electrophoretic
Micromirror
Electroluminescence
Inorganic
Thin film EL
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Electrochromic
Inorganic LEDs
Organic
Organic LEDs
Organic LEDs
Organic molecules
or polymers
H17C8
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C8H17 n
Organic LEDs
Organic molecules
or polymers
H17C8
C8H17 n
Philips
Wide viewing angle
Flexible /
wearable displays
(Pioneer)
What limits display efficiencies and lifetimes?
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What types of display are out there?
Cathode Ray Tube
Flat Panel
Displays
Emissive
Non-emissive
Liquid
Crystal
Plasma
Vacuum
fluorescent
Field
emission
Electrophoretic
Electrochromic
Electroluminescence
Inorganic
Thin film EL
Inorganic LEDs
Organic
Organic LEDs
Many different types and many questions to be answered!
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Micromirror