Surface-Conduction Electron-Emitter Display: Seminar

SEMINAR
on
Surface-conduction
electron-emitter
display
By
DEEPAK S N
(1JS06EC028)
TALK FLOW
•Common display technologies: Overview
CRT
LCD
PLASMA
•Surface-conduction electron-emitter display
•How SED works?
•Inside SED
•Comparison between different technologies
•Prototype models developed
•Beneficial Features
•Challenges
•References
COMMON DISPLAY
TECHNOLOGIES :
AN OVERVIEW
Cathode Ray Tube
Earliest displays
 A specialized vacuum tube in
which images are produced
when an electron beam strikes a
phosphorescent surface
Later RGB colour model for
displays in colour monitors
Affected by external fields
Bulky , high power
consumption and heat
production
How CRT works?
COLOR CRT
 Uses R, G and B
phosphors
 The three beams are
accelerated and focused by
the anode
Blue phosphors use zinc sulfide, while green ones use zinc sulfide and
cadmium sulfide. The red ones are hard to create, and are made from a
mixture of yttrium and europium, or gadolinium oxide.
Liquid Crystal Display
Displays thinner than (CRT) technology.

LCD’s consume much less power
Work on the principle of blocking light
rather than emitting it.
 LCD has a grid of conductors with pixels
located at each intersection in the grid. A
current is sent across two conductors on
the grid to control the light for any pixel.
Slow response time
 Less viewable angle
Difficulty in producing dark and grey
colours
How LCD works
 Formed by two glass layers

called substrates
 One is in charge of
columns, and the other is in
charge of rows
 Liquid crystals are
sandwiched in between
these two layers
 Uses a grid to charge
specific pixels
 When this happens the
crystals untwist and allow
light to pass through
Plasma
 Most mature flat panel technology

Electrical pulse excite a pixel
Wider angle view than LCD
Power consumption higher than
LCD
Complexity
Cost greater than LCD
Fragile technology : quite easy to
damage
PC connectivity less common since it is
developing
Plasma Display
• Each pixel is composed of three gas-filled capsules (RGB) that operate
on the same principle fluorescent lights .
 When a voltage is applied across the gas, free electrons bombard gas
atoms, causing some electrons to jump to higher energy levels. When
they fall back to stable energy level, a photon is emitted.
 The Xeon and Neon atoms in plasma screens release ultra-violet photons.
 These ultra-violet photons collide with a phosphor coating and create
visible light.
• An electrode grid is used to turn individual pixels on and off .
Glass
Display Electrode
Phosphor-Coated Cells
Address Electrode
Pixel
Buzz into SED ??
 Wider angle view !!!!
 Lower cost !!!!
 Superior picture quality !!!!
 Less complexity in overall terms !!!!
“ SURFACE CONDUCTION
ELECTRON EMITTER DISPLAY ”
 Combine CRT into LCD technology.
 Millions of miniature CRTs, called •Formed in 2004 between Toshiba
surface-conduction electron emitters and Canon
•Created SED Co. LTD for developing
(SCEs) embedded in surface.
and producing SED technology
 “High quality picture in low •Canon for electron source
centimeter thickness” technology
 Only 3cm thickness •Toshiba for the display
Surface-Conduction Electron-Emitter Display
• SEDs work on the same principle as CRTs
 One side of a glass is covered in phosphor that lights up when hit by
electrons
 Electrons are fired at the phosphor to create the picture
• However, where CRTs use one electron gun for the whole screen,
SEDs use an electron emitter for each pixel
• A SED is an array of Surface-Conduction Electron-Emitters (SCEs),
each of which has a separate emitter for RGB
Glass
Colored Phosphor
Electrons
Electron Emitters
Glass
Surface-Conduction Electron-Emitter (SCE) SED

how SED works ??
•An SCE is microscopic,
and it consists of a layer
of carbon with a gap down
the center.
•One half of the carbon

layer connects to a
negative electrode, and
the other connects to a
positive electrode.
•When the circuitry

delivers about 10 volts of
current to the SCE,
electrons appear at one
side of the gap.
SCE MATRIX
One
SCE
pixel
An SED-TV has millions of these SCE s

arranged in a matrix , and each one
controls the Red, Green or Blue aspect
of one pixel of the picture. Rather than
directing electrons to create the image
one row at a time, the matrix activates
all the SCE s needed to create the
picture virtually simultaneously
In short……............
………………tied
……………… together
 When the SED-TV receives a signal,,
a) Scans the signal
b) Decides what to do with the red, green and blue

aspect of each pixel
c) Activates the necessary SCE s, which generate

electrons that fly through the vacuum to the
screen
Comparison between different
technologies
Prototype models developed
Developed by Canon
Snaps from sed tv’s
Beneficial Features
Sharp resolution and fast response(1ms) and only 3cms in thickness
 Excellent colour and contrast potential
Relatively inexpensive production cost
180º Viewing angle.
Extremely low power consumption
Lower cost than LCD or PLASMA
It can be used in Mobile device display

Challenges
Unknown (though optimistic) life expectancy
Potential for screen burn-in : but expected to

overcome due to phosphor development
Currently prototype only expected soon
Due to ongoing patent litigation, not currently mass-

produced
References:
 Invited Paper: A 36-inch Surface-conduction Electron-emitter
Display (SED)
T. Oguchi, E. Yamaguchi, K. Sasaki, K. Suzuki, S. Uzawa SED Inc., Kanagawa,
Japan
K. Hatanaka ,Canon Inc., Kanagawa, Japan
 Audioholics
 www.howstuffworks.com
 www.about.com
 Wikipedia
 www.physorg.com/news1295.html
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SEMINAR

Displays thinner than (CRT) technology.

 Formed by two glass layers

 Most mature flat panel technology

Surface-Conduction Electron-Emitter (SCE) SED

•One half of the carbon

•When the circuitry

An SED-TV has millions of these SCE s

a) Scans the signal

b) Decides what to do with the red, green and blue

c) Activates the necessary SCE s, which generate

 Excellent colour and contrast potential

Relatively inexpensive production cost

180º Viewing angle.

Extremely low power consumption

Lower cost than LCD or PLASMA

It can be used in Mobile device display

Unknown (though optimistic) life expectancy

Potential for screen burn-in : but expected to

Currently prototype only expected soon

Due to ongoing patent litigation, not currently mass-

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