SED SEMINAR REPORT JOJI

SED – SURFACE CONDUCTION ELECTRON EMITTER DISPLAY 1

CONTENTS

SL NO. CHAPTERS PAGE NO.

1 ABSTRACT 4

2

2.1

INTRODUCTION

PROBLEM DEFENITION

5

7

3 HISTORY 10

4

4.1

4.2

WORKING

CREATING THE

PICTURE

FABRICATION OF

NANO GAPS

13

14

26

5 COMPARISON 30

DEPARTMENT OF ELECTRONICS & INSTRUMENTATION GPTC CHERTHALA


6

6.1

6.2

6.3

6.4

ADVANTAGES

SED TV COMPARED TO

CRT

SED TV COMPARED TO

PLASMA

DISADVANTAGES OF

PLASMA TV

SED TV COMPARED TO

LCD TV

31

31

32

33

36

7 DISADVANTAGES 41

8 FEATURES 42

9 APPLICATIONS 43

10 FUTURE 44

11 CONCLUSION 46

12 REFERENCE 48



LIST OF FIGURES

LIST OF TABLES

TABLE NO. DESCRIPTION PAGE

Table 1 Color-Phase

relationship

24

Table 2 Display technology

comparisons

30

1. ABSTRACT


FIGURE NO. DESCRIPTION PAGE NO.

Figure 1 SED basic diagram 15

Figure 2 SED working 16

Figure 3 Color Matrix 18

Figure 4 Internal diagram 20

Figure 5 Sync pulse 23

Figure 6 Electron path 25

Figure 7 SED-CRT comparison 32

Figure 8 Demonstration 38

Figure 9 Prototype of SED 45


A surface-conduction electron-emitter display

(SED) is a display technology which has been developing

various flat panel displays by a number of companies as

a electronic visual displays.SEDs use nanoscopic scale

electron emitters to energize colored phosphors and

produce an image. In a general sense, a SED consists of a

matrix of tiny cathode ray tubes, each "tube" forming a

single sub-pixel on the screen, grouped in threes to form

red-green-blue (RGB) pixels. SEDs combine the

advantages of CRTs, namely their high contrast ratios,

wide viewing angles and very fast response times, with the

packaging advantages of LCD and other flat panel

displays. They also use much less power than an LCD

television of the same size.

After considerable time and effort in the early and

mid-2000s, SED efforts started winding down in 2009 as

LCD became the dominant technology. In August

2010, Canon announced they were shutting down their joint

effort to develop SEDs commercially, signalling the end of

development efforts.



2. INTRODUCTION

The SED technology has been developing since 1987.

The flat panel display technology that employs surface

conduction electron emitters for every individual display

pixel can be referred to as the Surface-conduction Electron-

emitter display(SED). Though the technology differs, the

basic theory that the emitted electrons can excite a phosphor

coating on the display panel seems to be the bottom line for

both the SED display technology and the traditional cathode

ray tube (CRT) televisions. When bombarded by moderate

voltages (tens of volts), the electrons tunnel across a thin slit

in the surface conduction electron emitter apparatus. Some of

these electrons are then scattered at the receiving pole and are

accelerated towards the display surface, between the display

panel and the surface conduction electron emitter apparatus,

by a large voltage gradient (tens of kV) as these electrons

pass the electric poles across the thin slit. These emitted

electrons can then excite the phosphor coating on the display

panel and the image follows.

The main advantage of SED’s compared with LCD’s

and CRT’s is that it can provide with a best mix of both the



technologies. The SED can combine the slim form factor of

LCD’s with the superior contrast ratios, exceptional response

time and can give the better picture quality of the CRT’s. The

SED’s also provides with more brightness, color

performance, viewing angles and also consumes very less

power . Moreover, the SED’s do not require a deflection

system for the electron beam, which has in turn helped the

manufacturer to create a display design, that is only few

inches thick but still light enough to be hung from the wall

All the above properties has consequently helped the

manufacturer to enlarge the size of the display panel just by

increasing the number of electron emitters relative to the

necessary number of pixels required. Canon and Toshiba are

the two major companies working on SED’s. The technology

is still developing and we can expect further breakthrough on

the research.

2.1 PROBLEM DEFENITION



The only constant that we can count on is change.

Nowhere is this more accurate than with display

technologies. All manufactures are trying to reduce their

manufacturing cost profiles by introducing new techniques.

SED technology, or surface conduction electron-emitter

displays, that has been shown at selected shows for the last

few years by the recently disbanded joint venture between

Canon and Toshiba.

CRTs are typically as wide as they are deep. CRTs can

have image challenges around the far edges of the picture

tube. But their thickness is much more.

Plasma TV shows close to black colour, gray levels

actually showing up. This means they are actually dark gray –

not black. Plasma has been getting better in this regard but

still has a way to go to match as CRT. The pixels in a Plasma

panel are inherently digital devices that have only two states,

on and off. A Plasma produces gradations of light intensity

by changing the rate at which each pixel produces its own

series of very-short, equal-intensity flashes.



LCD latency has been a problem with television

pictures with an actual 16ms speed needed in order to keep

up with a 60Hz screen update. Also, due to LCD's highly

directional light, it has a limited angle of view and tends to

become too dim to view off axis, which can limit seating

arrangements. LCD generally suffers from the same black

level issues and solarization, otherwise known as false

contouring, that Plasma does. The impact of the LCD

television on the modern generation shows one thing that

there is no space for the old and conventional models. Those

days are gone by when a person had to buy an old and

conventional television set which occupied the large space in

room. Now the sleek large flat LCD screen is so sophisticated

and cute looking that it enhances the design of the room. It is

a work of art. Large Acquos is weather resistant. So with the

change of the weather and temperature of the room there will

be no harm in the LCD.

The real and transparent picture can enable a viewer to

watch the movies with the great mental satisfaction.

However, there are a number of demerits of the LCD

television. The first disadvantage is the high power

consumption and heat output. If someone wants to place a

small serene size television in the pantry room, LCD is the



best but there is one disadvantage of the poor color contrast.

In comparison to the plasma television, the color contrast is

of poor quality. Simultaneously, there is another demerit

being present in the LCD television is poor and substandard

SD video processing. Most of the LCD televisions are

equipped with non reflective face. Next is the power

consumption. The LCD television consumes 280W power. So

high power consumption will be a negative side of the LCD .

The picture quality is good and up to the mark but iTV in

LCD is very old and stereotyped.

Finally, the prices of the LCD television are still

higher. So instead of purchasing expensive LCD television

one can opt for the plasma television sets. In the case of LCD

computer, the slow startups and high recycling time are the

demerits to the LCD computers. Due to the faint horizontal

stripes some users can make the replacement of the LCD

computers. Lastly there is some dearth of RGB inputs and

dubbing difficulties being present in the LCD.

3. HISTORY



Canon began SED research in 1986 and, in 2004,

Toshiba and Canon announced a joint development

agreement originally targeting commercial production of seds

by the end of 2005. The 2005 target was not met, and several

new targets since then have also slipped by. This failure to

meet mass-production deadlines goes as far back as 1999,

when Canon first told investors of its intentions to

immediately begin mass-producing the technology. The lack

of tangible progress has worried many investors and has

prompted many critics. One critic called SED “the best

display technology you’ve ever seen that may be stillborn”.

During the 2006 Consumer electronics show in Las Vegas,

Nevada. Toshiba showed working prototypes of seds to

attendees and indicated expected availability in mid-to-late

2006. Toshiba and Canon again delayed their plan to sell the

television sets to the fourth quarter of 2007. At the 2007

Consumer Electronics Show, no SED displays were to be

found on the show floor. This led many analysts to speculate

that the technology would never reach the consumer market.

In October 2006, Toshiba's president announced the

company plans to begin full production of 55-inch SED tvs in



July 2007 at its recently built SED volume-production facility

in Himeji. In December 2006, Toshiba President and Chief

Executive Atsutoshi Nishida said Toshiba is on track to mass-

produce SED TV sets in cooperation with Canon by 2008. He

said the company plans to start small-output production in the

fall of 2007, but they do not expect SED displays to become a

commodity and will not release the technology to the

consumer market because of its expected high price,

reserving it solely for professional broadcasting applications.

The formation of SED Inc. In 2004 was certainly an

acknowledgement by Canon that, no matter how good their

engineering and technical prowess, they would have a

difficult time manufacturing and mass-marketing this

technology on their own.

While CES 2005 was the moment for SED to prove its

technology was alive and kicking, CEATAC 2005 and CES

2006 showed that SED Inc. Could make multiple versions of

that same 36-inch display with repeatable image quality and

consistency. Hopefully we will see a Canon SED TV display

at both CEATEC in Japan starting September 30th and

CES2009 in Las Vegas next January. Canon has a reissue



patent covering SED TV technology. United States Patent

RE40, 062 was reissued February 12, 2008. It apparently has

some modifications from previous SED TV patents. This may

be the beginning of Canon’s attempt to produce SED panels

without using the Nano-Proprietary patented technology.

4. WORKING



The flat panel display technology that employs surface

conduction electron emitters for every individual display

pixel can be referred to as the Surface-conduction Electron-

emitter Display (SED). Though the technology differs, the

basic theory that the emitted electrons can excite a phosphor

coating on the display panel seems to be the bottom line for

both the SED display technology and the traditional cathode

ray tube (CRT) televisions.

A conventional cathode ray tube (CRT) is powered by

an electron gun, essentially an open-ended vacuum tube. At

one end of the gun electrons are produced by "boiling" them

off a metal filament, which requires relatively high currents

and consumes a large proportion of the CRT's power budget.

The electrons are then accelerated and focused into a fast

moving beam, flowing forward towards the screen.

Electromagnets surrounding the gun end of the tube are used

to steer the beam as it travels forward, allowing the beam to

be scanned across the screen to produce a 2D display. When

the fast moving electrons strike phosphor on the back of the

screen, light is produced. Color images are produced by

painting the screen with spots or stripes of three colored


http://en.wikipedia.org/wiki/Phosphor

http://en.wikipedia.org/wiki/Electromagnet

http://en.wikipedia.org/wiki/Vacuum_tube

http://en.wikipedia.org/wiki/Electron_gun

http://en.wikipedia.org/wiki/Cathode_ray_tube


phosphors, one each for red, green and blue (RGB). When

viewed from a distance, the spots, known as "sub-pixels",

blend together in the eye to produce a single colored spot

known as a pixel.

4.1 CREATING THE PICTURE


http://en.wikipedia.org/wiki/Pixel


The SED replaces the single gun of a conventional CRT

with a grid of nanoscopic emitters, one for each sub-pixel of

the display. The surface conduction electron emitter

apparatus consists of a thin slit across which electrons jump

when powered with high-voltage gradients. Due to the

nanoscopic size of the slits, the required field can correspond

to a potential on the order of tens of volts. A few of the

electrons, on the order of 3%, impact with slit material on the

far side and are scattered out of the emitter surface.

FIG 1



A second field, applied externally, accelerates these

scattered electrons towards the screen. Production of this

field requires kilovolt potentials, but is a constant field

requiring no switching, so the electronics that produce it are

quite simple. Each emitter is aligned behind a colored

phosphor dot, and the accelerated electrons strike the dot and

cause it to give off light in a fashion identical to a

conventional CRT. An SED-TV creates a picture in much the

same way. It's essentially a flat panel television that uses

millions of CRTs instead of one electron gun. These



miniature CRTs are called Surface Conducting Electron

emitters (SCEs). A set has three SCEs for every pixel -- one

each for Red, Green and Blue. A widescreen, high definition

set can have more than 6 million SCEs.

FIG 2

Since each dot on the screen is lit by a single emitter,

there is no need to steer or direct the beam as there is in an

CRT. The tunneling effect that emits electrons across the slits

is highly non-linear, and the process tends to be fully on or


http://en.wikipedia.org/wiki/Quantum_tunneling


off for any given voltage. This allows the selection of

particular emitters by powering a single horizontal row on the

screen and then powering all of the needed vertical columns

at the same time, thereby powering the selected emitters. Any

power leaked from one column to surrounding emitters will

cause too small a field to produce a visible output; However,

this also means that changes in voltage cannot be used to

control the brightness of the resulting pixels. Instead, the

emitters are rapidly turned on and off using pulse width

modulation, so that the total brightness of a spot in any given

time can be controlled. An SED-TV has millions of these

SCEs 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 SCEs needed to create the picture

virtually simultaneously (FIG 2).

FIG 3


http://en.wikipedia.org/wiki/Pulse_width_modulation

http://en.wikipedia.org/wiki/Pulse_width_modulation


As with a CRT set, the inside of an SED-TV is a

vacuum. All of the SCEs are on one side of the vacuum, and

the phosphor-coated screen is on the other The phosphors are

painted onto the screen using a variety of silk screening or

similar technologies, and then covered with a thin layer of

aluminum to make the screen visibly opaque and provide an

electrical return path for the electrons once they strike the

screen. The screen has a positive electrical charge, so it

attracts the electrons from the SCEs. In the SED, this layer



also serves as the front electrode that accelerates the electrons

toward the screen, held at a constant high voltage relative the

switching grid When bombarded by moderate voltages (tens

of volts), the electrons tunnel across a thin slit in the surface

conduction electron emitter apparatus. Some of these

electrons are then scattered at the receiving pole and are

accelerated towards the display surface, between the display

panel and the surface conduction electron emitter apparatus,

by a large voltage gradient (tens of kV) as these electrons

pass the electric poles across the thin slit. These emitted

electrons can then excite the phosphor coating on the display

panel and the image follows.

When they reach the screen, the electrons pass through

a very thin layer of aluminum. They hit the phosphors, which

then emit red, green or blue light. Our eyes and brain

combine these glowing dots to create a picture (FIG 3).

FIG 4



Any part of the screen that's not used to create pixels is

black, which gives the picture better contrast. There's also a

color filter between the phosphors and the glass to improve

color accuracy and cut down on reflected light.

To tie it all together, when the SED-TV receives a

signal, it:

A. Decodes the signal



B. Decides what to do with the red, green and blue aspect of

each pixel

C. Activates the necessary SCEs, which generate electrons

that fly through the vacuum to the screen When the electrons

hit the phosphors, those pixels glow, and your brain combines

them to form a cohesive picture. The pictures change at a rate

that allows you to perceive them as moving. This process

happens almost instantaneously, and the set can create a

picture sixty times per second. Unlike a CRT, it doesn't have

to interlace the picture by painting only every other line. It

creates the entire picture every time.

A phosphor is any material that, when exposed to

radiation, emits visible light.The radiation might be

ultraviolet light or a beam of electrons. Any fluorescent color

is really a phosphor -- fluorescent colors absorb invisible

ultraviolet light and emit visible light at a characteristic color.

In a CRT, phosphor coats the inside of the screen.

When the electron beam strikes the phosphor, it makes the

screen glow. In a black-and-white screen, there is one

phosphor that glows white when struck. In a color screen,

there are three phosphors arranged as dots or stripes that emit


http://www.howstuffworks.com/light2.htm


red, green and blue light. There are also three electron beams

to illuminate the three different colors together.

There are thousands of different phosphors that have

been formulated. They are characterized by their emission

color and the length of time emission lasts after they are

excited.

A signal that contains all three of these components --

intensity information, horizontal-retrace signals, and vertical-

retrace signals -- is called a composite video signal. A

composite-video input is normally a yellow RCA jack. The

horizontal-retrace signals are 5-microsecond (abbreviated as

"us" in the figure) pulses at zero volts. Electronics inside the

TV can detect these pulses and use them to trigger the beam's

horizontal retrace. The actual signal for the line is a varying

wave between 0.5 volts and 2.0 volts, with 0.5 volts

representing black and 2 volts representing white. This signal

drives the intensity circuit for the electron beam. In a black-

and-white TV, this signal can consume about 3.5 megahertz

(MHz) of bandwidth, while in a color set the limit is about

3.0 MHz.

A vertical-retrace pulse is similar to a horizontal-

retrace pulse but is 400 to 500 microseconds long. The



vertical-retrace pulse is serrated with horizontal-retrace

pulses in order to keep the horizontal-retrace circuit in the TV

synchronized.

A color TV signal starts off looking just like a black-

and-white signal. An extra chrominance signal is added by

superimposing a 3.579545 MHz sine wave onto the standard

black-and-white signal. Right after the horizontal sync pulse,

eight cycles of a 3.579545 MHz sine wave are added as a

color burst.

FIG 5

Following these eight cycles, a phase shift in the

chrominance signal indicates the color to display. The

amplitude of the signal determines the saturation. The



following table shows you the relationship between color and

phase:

TABLE 1

A black-and-white TV filters out and ignores the

chrominance signal. A color TV picks it out of the signal and



decodes it, along with the normal intensity signal, to

determine how to modulate the three color beams.

FIG 6

When a color TV needs to create a red dot, it fires the

red beam at the red phosphor. Similarly for green and blue



dots. To create a white dot, red, green and blue beams are

fired simultaneously -- the three colors mix together to create

white. To create a black dot, all three beams are turned off as

they scan past the dot. All other colors on a TV screen are

combinations of red, green and blue.

4.2 FABRICATION OF NANO GAPS



Nanogaps are the electron guns of SED.A nanometer

scale gap (nanogap) structure in palladium strip fabricated by

hydrogen absorption under high-pressure treatment. It is

found that the edge roughness of the nanogap improves the

electron emission characteristics. The electron emission

current is dependent upon the angle of inclination of surface.

Hydrogen plasma treatment is used to increase the edge

roughness of the nanogap and thereby dramatically improve

the electron emission characteristics. For the nanogap with a

separation of 90 nm, the turn-on voltage significantly reduces

from 60 to 20 V after the hydrogen plasma treatment.

Modern SEDs add another step that greatly eases

production. The pads are deposited with a much larger gap

between them, as much as 50 nm, which allows them to be

added directly using technology adapted from inkjet printers.

The entire screen is then placed in an organic gas and pulses

of electricity are sent through the pads. Carbon in the gas is

pulled onto the edges of the slit in the PdO squares, forming

thin films that extend vertically off the tops of the gaps and

grow toward each other at a slight angle.


http://en.wikipedia.org/wiki/Inkjet_printer


This process is self-limiting; if the gap gets too small

the pulses erode the carbon, so the gap width can be

controlled to produce a fairly constant 5 nm slit between

them. Many new methods are implemented for the fabrication

of nano gap electrodes. the following is one of the latest one.

Having the ability to trap an individual molecule between two

electrodes is very desirable for several reasons, two of which

are; being able to measure the electrical properties of a single

molecule and being able to fabricate devices significantly

smaller than previously thought possible. The first step in

being able to achieve both of these goals is to have a device

in which the gap between the two electrodes is small enough

such that a single molecule will fit snugly between them.

These devices can be made using electron-beam (e-beam)

lithography and photolithography. Both approaches are

similar in that in each process, shorted devices are patterned

then broken by applying a voltage yielding the desired gap.

The advantage of using e-beam lithography is that very small

feature sizes can be patterned which, in turn, can be broken to

give gaps on the range of 2-3 nm. Dai et al. and others have

already made these devices and the results are shown in

Figure 1, showing that breakdown occurs at ~1.68 volts.



The inset graph shows the tunneling current across the

newly formed gap, indicating a gap size of nm scale. The

disadvantages to using e-beam are that it is very time

consuming, expensive, and it cannot be mass reproduced.

This method is inexpensive using conventional

photolithography that can make devices similar to those made

using e-beam lithography but on a wafer scale.

In order to obtain the desired gap size between the two

electrodes, two separate masks were designed, one for the

source electrode (half circle) and one for the drain electrode

(small finger). The masks were designed to have various

spacings between the electrodes with the hopes that any

misalignment would still yield some functional devices.

Starting with a ptype silicon substrate, a thin 10 nm gate

oxide was grown. The source electrode was patterned using

photolithography, and 0.5 nm Ti and 10 nm Au was deposited

using e-beam evaporation.

The drain electrode was patterned in the same manner,

followed by evaporation of another 0.5 nm Ti and 10 nm Au.

The unwanted metal and photoresist were removed by



soaking the wafer in acetone for three hours. Upon closer

inspection, it was determined that most of the devices had

gaps between the two electrodes ranging from 100-250 nm

(due to misalignment). The approach we intended to use

required a very small overlap of the two electrodes so we

patterned the source electrode again. This time only 0.5 nm

of Ti and 7 nm Au were deposited, followed by soaking the

wafer in acetone for three hours to remove the remaining

photoresist and metal. The devices were then cooled to 4K

using a liquid helium dewar followed by electrical

breakdown.

5. COMPARISON



This is a comparison of various properties of different

display technologies.

TABLE 2

Comparison of various properties of different display

technologies.

6. ADVANTAGES



SEDs promise the same advantages over LCDs and

Plasmas as CRTs are delivering today plus they will also be

thin and much larger than CRTs.

6.1 SED TV COMPARED TO CRT

SED is flat. A traditional CRT has one electron gun that

scans side to side and from top to bottom by being deflected

by an electromagnet or "yoke". This has meant that the gun

has had to be set back far enough to target the complete

screen area and, well, it starts to get ridiculously large and

heavy around 36". CRTs are typically as wide as they are

deep. They need to be built like this or else the screen would

need to be curved too severely for viewing. Not so with SED,

where you supposedly get all the advantages of a CRT

display but need only a few inches of thickness to do it in.



Screen size can be made as large as the manufacturer

dares. Also, CRTs can have image challenges around the far

edges of the picture tube, which is a non-issue for SED. Side

views of crt and sed prototype are shown in FIG 7.

FIG 7

6.2 SED TV COMPARED TO PLASMA TV



Compared to Plasma the future looks black indeed. As

in someone wearing a black suit and you actually being able

to tell it's a black suit with all those tricky, close to black,

gray levels actually showing up. This has been a major source

of distraction for this writer for most display technologies

other than CRT. Watching the all-pervasive low-key (dark)

lighting in movies, it can be hard to tell what you're actually

looking at without the shadow detail being viewable. Think

Blade Runner or Alien.

SED's black detail should be better, as Plasma cells

must be left partially on in order to reduce latency. This

means they are actually dark gray – not black. Plasma has

been getting better in this regard but still has a way to go to

match a CRT. Hopefully, SED will solve this and it's likely

to. Also, SED is expected to use only half the power that a

Plasma does at a given screen size although this will vary

depending on screen content.

6.3 DISADVANTAGES OF PLASMA TV



6.3.1 Potential Burn-In

Because of the phosphor technology in Plasma TVs, it

is possible for traces of an image to be 'burned-in' to the

display. This is generally only a concern in commercial uses,

where images are displayed for long-periods of time. Those

that watch stations that offer news tickers may also need to be

careful. Burn-in can generally be avoided by making sure that

you do not keep a constant image on the screen for extended

periods (sometimes as little as 20 minutes), either by turning

the television off, or changing the channel.

6.3.2 Lower Brightness



Although still considerably brighter than rear-projection

TVs, direct view and LCD TVs often are able to provide a

brighter picture. This is generally only readily noticeable if

watching in a very brightly lit room. Latest generation

Plasma TVs have improved on the brightness issue

considerably, and our only real warning would be to those

that plan to do the majority of their viewing in a room

exposed to afternoon sun.

6.3.3 Not the Lightest or Slimmest

Although Plasma TVs are MUCH lighter and thinner

compared to direct view and rear projection TVs, a lighter,

slimmer technology does exist: LCD TVs. LCD TVs use the

same technology as used in most laptop computers. However,

it should be noted that LCD TVs are not generally available

in the same sizes as Plasma TVs, and in those rare cases that

they are, they generally cost considerably more.

6.3.4 Price



Yes, this is a disadvantage and an advantage. Although

Plasma TVs are considerably cheaper than comparably-sized

LCD or LCoS TVs, they do cost more than direct view and

rear-projection TVs. Of course, it must be mentioned that

direct view HDTVs do not exist in the sizes that Plasma TV

offers (namely 42-inch and 50-inch models).

6.3.5 Shorter Life

Compared to other television technologies, Plasma TVs

do generally have a shorter life span, and there is no option to

repair a burnt out tube or backlight. Most Plasma TVs have a

life span of 20,000-30,000 hours based on manufacturer's

estimates. This life span is commonly referred to as the

Plasma TV half-life, as it is the number of hours over which

the Plasma TV will loose approximately half of it's

brightness.

Of course, we should note that a Plasma TV with a

20,000 hour life would allow you to watch 4 hours of TV per

day for approximately 13.7 years. Even at 8 hours per day,

your Plasma TV should provide you with nearly 7 years of



enjoyment. So, for most of us, this should not be an issue,

and a Plasma TV is a worthy investment.

6.3.6 Fragility

Plasma TVs are a very fragile technology, and the units

are quite easy to damage. Extreme care must be used when

moving them, as even laying the Plasma display on it's side

can have adverse effects, possibly damaging the unit

irreparably.

6.4 SED TV COMPARED TO LCD TV



LCDs have had a couple of challenges in creating great

pictures but they are getting better. Firstly, latency has been a

problem with television pictures with an actual 16ms speed

needed in order to keep up with a 60Hz screen update. There

is no motion blur in SED. LCDs still suffer from motion blur

of fast-moving scenes such as most sports.

Also, due to LCD's highly directional light, it has a

limited angle of view and tends to become too dim to view

off axis, which can limit seating arrangements. This will not

be an issue for SED's self illuminated phosphors Full

dynamic contrast range. LCDs only show about 6-bits of

contrast shades of gray at the same time. Thus outdoor scenes

in bright light always block up the blacks and bleach out the

whites. SED shows the Peak brightness. The fixed backlight

brightness is as bright as any part of a scene can get. Yet

CRTs (and SEDs) can produce peak brightness much brighter

(over a small area and for a short time). This adds "sparkle"

and liveliness to a scene.

However, LCD does have the advantage of not being

susceptible to burn-in which any device using phosphors will,

including SED. SED is likely to use about two-thirds the



power of a similarly sized LCD. Generally LCD suffers from

the same black level issues and solarization, otherwise known

as false contouring, that plasma does. SED does not.

LCDs do not directly produce light, and have to be

back-lit using cold cathode fluorescent lamps (CCFLs) or

high-power LEDs. The light is first passed through a

polarizer, which cuts out half of the light. It then passes

through the LCD layer, which selectively reduces the output

for each sub-pixel. In front of the LCD shutters are small

colored filters, one for each RGB sub-pixel. Since the colored

filters cut out all but a narrow band of the white light, the

amount of light that reaches the viewer is always less than

1/3rd of what left the polarizer. Since the color gamut is

produced by selectively reducing the output for certain

colors, in practice much less light makes it through to the

view, about 8 to 10% on average. In spite of using highly

efficient light sources, an LCD display uses about the same

power as a CRT of the same size.

FIG 8


http://en.wikipedia.org/wiki/LED

http://en.wikipedia.org/wiki/Fluorescent_lamp

http://en.wikipedia.org/wiki/Cold_cathode


The figure above (FIG 7) shows the LCD and SED

TVs.LCD shutters consist of an encapsulated liquid that

changes its polarization in response to an applied electrical

field. This response is fairly linear, so even a small amount of

leaked power that reaches surrounding shutters causes the

image to become blurry. To counteract this effect, and



improve switching speed, LCD displays use an active matrix

of transparent thin-film transistors to directly switch each

shutter. This adds complexity to the LCD screen and makes

them more difficult to manufacture. The shutters are not

perfect and allow light to leak through, which means that the

contrast ratio of an LCD is less than a CRT, and this causes

the color gamut to be reduced as well. Additionally the use of

a polarizer to create the shutter limits the viewing angles

where this contrast can be maintained. Most importantly, the

switching process takes some time, on the order of

milliseconds, which leads to blurring on fast moving scenes.

Massive investment in the LCD manufacturing process has

addressed all of these concerns to some degree.

The SED produces light directly on its front surface.

Scenes are lit only on those pixels that require it, and only to

the amount of brightness they require. In spite of the light

generating process being less efficient than CCFLs or LEDs,

the overall power efficiency of an SED is about ten times

better than a LCD of the same size. SEDs are also much less

complex in overall terms – they lack the active matrix layer,

backlighting section, color filters and the driver electronics

that adjusts for various disadvantages in the LCD shuttering


http://en.wikipedia.org/wiki/Thin-film_transistor

http://en.wikipedia.org/wiki/Active_matrix


process. Despite of having two glass layers instead of one in

a typical LCD, this reduction in overall complexity makes

SEDs similar in weight and size as LCDs.

7. DISADVANTAGES



As with any phosphor-based technology, SED may also

be susceptible to screen burn-in. This was a constant problem

for people using CRT television monitors for security camera

systems. Early plasmas also had this problem, but with

phosphor development, the problem has largely been reduced

The cost of flat panels is largely dependent on production

yields of saleable product. New technology is always

expensive in early production. .By the use of inkjet

technology to make SED displays rather than the more

expensive photolithography to drop .The price of plasma

displays is expected to continue .

8. FEATURES



Contrast ratio 50,000:1. Toshiba's final versions of SEDs

will have a contrast ratio of 100,000:1.

Response time 0.2 milliseconds.

Brightness of 450 cd/m2.

180º Viewing angle.

Viewable in Bright room.

It can be used in Mobile device display.

Low power consumption.

Longer life expectancy.

It is available from 16 inches to more.

The SED made available with HD view .

It capable to show 1080i picture quality and video films.

It nVidia GeForce nForce graphics to show 3D videos.

It is made with true 5.1 DTS surround sound and can

upgrade to 7.1 DTS surround sound.

It can be easily upgraded as a smart tv , because it runs on

the ANDROID v 4.0 ICECREAM SANDITCH OS so it

can be used for various purposes.

9. APPLICATIONS



Used in corporate firms.

Public display areas such like railway station , airports,

Govt:offices etc..

For home theatre systems .

In hospitals as surgical display supporters.

In lounge areas , such like NASA or ISRO.

In process industries .

In distributed control systems.

It can be used at places where 50 inches and larger flat

panel tv’s can be used.

In professional communication and broadcasting

community.

It can be used for browsing internet , playing video games,

Social networking and for video calling etc…

10. FUTURE



The SED TV’s are positioned to compete directly with

LCD and plasma TV’s. The technology is now in a

developing stage. several researches are going on. Different

models of the display are available. Application specification,

variation are expected in the very near future. It is expected

to deliver more quality products in the market at a

competitive price. Looking back at the issues that have

surrounded the much awaited SED TV launch, product

inventors and manufacturers should hasten the launch process

and start patching the loop holes that have caused the

considerable delay.

FIG 9

PROTOTYPE OF SED



The figure shows the prototype of the SED TV that

going to be lunched on this December by the TOSHIBA co.

11. CONCLUSION



Anyone interested in getting a high definition television

that can present the best picture imaginable should invest in a

sedtv. An sed tv has been designed in such a way that the

pictures it offers are awe-inspiring with every view. This set

has impressive sed technologies inside which make every

pixel perfect whenever it is presented. If you like a set that

can give you a lot of diversity in terms of viewing angles, and

you want an HDTV that doesn’t have problems with digital

noise, edge fading, or color diminishment, than an sedtv is

the selection you need to get.

An SED tv is something that is suitable for just about

anyone looking for awesome technologies inside a slender

television frame. You won’t lose the option to mount the

television to a wall if you invest in an sedtv because these

sets are designed with incredibly thin frames. You can also

place them in a super shallow shelf if you want to, or you can

set them on a tabletop. This means that you can use the sedtv

at home, in the office, or just about anywhere that you might

want to view the television set.

SED will be the next generation display technology in

the near by future. Hopefully we will see a Canon SED TV

display at both CEATEC in Japan starting September 30th



and CES2009 in Las Vegas next January. Reissue patent

covering SED TV technology may be the beginning of

Canon’s attempt to produce SED panels without using the

Nano-Proprietary patented technology.

12. REFERENCE



Nanotechnology, IEEE Transactions on Volume 7,

Issue 4, July 2011.

A paper on Nanotechnology, Department of

Communication.

Engineering, National Chiao Tung University.

www.joji-josey.blogspot.com

www.canon.com

www.thoshiba.com

www.electronics.howstuffworks.com

www.howstuffworks.com

en.wikipedia.com


http://www.howstuffworks.com/

SED SEMINAR REPORT JOJI

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