Thin Film Transistor Liquid Crystal Display

8/6/2019 Thin Film Transistor Liquid Crystal Display

http://slidepdf.com/reader/full/thin-film-transistor-liquid-crystal-display 1/20

Thin film transistor liquid crystal display (TFT-LCD) is a variant

of liquid crystal display (LCD) which uses thin-film transistor (TFT)

technology to improve image quality (e.g., addressability, contrast).

TFT LCD is one type of active matrix LCD, though all LCD-screens

are based on TFT active matrix addressing. TFT LCDs are usedin television sets, computer monitors, mobile phones, handheld video

game systems, personal digital assistants, navigation

systems, projectors, etc.[1]

Contents

[hide]

1 Construction

2 Types

o 2.1 Twisted nematic (TN)

o 2.2 In-plane switching (IPS)

o 2.3 Advanced fringe field switching (AFFS)

o 2.4 Multi-domain vertical alignment (MVA)

o 2.5 Patterned vertical alignment (PVA)

o 2.6 Advanced super view (ASV)

3 Display industry

4 Electrical interface

5 Safety

o 5.1 Toxicity

6 See also

7 References

8 External links

[edit]Construction





based s are by f ar t e st due t t eir l er roduction

cost, ereas olycrystalline silicon s are ore costly and difficult

to roduce[3]

.

[edit] ypes

[edit]Twisted em ti (TN)

N display under a icroscope, it

t

e transistors isible at t

e bottom

e not so expensi e t isted nematic display is t e most common consumer display type. e pixel response time on modern N panels

is sufficiently f ast to avoid t e shadow-trail and hosting ar tif acts of

ear lier production. he f ast response time has been emphasised in

adver tising N displays, although in most cases this number does not

reflect per f ormance across the entire range of possible color

transitions.[c it tion n

d d ]

More recent use of R Response ime

ompensation / Overdr ive) technologies has allowed manuf acturers

to significantly reduce grey-to-grey G2G) transitions, without

significantly improving the ISO response time. Response times are now uoted in G2G figures, with 4ms and 2ms now being

commonplace f or N-based models. he good response time and low

cost has led to the dominance of N in the consumer mar ket.[c it tion

n d d ]

N displays suff er f rom limited viewing angles, especially in the

ver tical direction. olors will shift when viewed off -perpendicular . In



the vertical direction, colors will shift so much that they will invert past

a certain angle.

Also, most T panels represent colors using only six bits per B

color, or 18 bit in total, and are unable to display the 16.7 million color

shades ( -bittruecolor ) that are available from graphics cards.Instead, these panels display interpolated -bit color using

a dithering method that combines adjacent pixels to simulate the

desired shade. They can also use a form of temporal dithering

called Frame ate Control (F C), which cycles between different

shades with each new frame to simulate an intermediate shade. Such

18 bit panels with dithering are sometimes advertised as having "16.

million colors". These color simulation methods are noticeable to

many people and highly bothersome to some.[

]F C tends to be most

noticeable in dar er tones, while dithering appears to ma e theindividual pixels of the LCD visible. verall, color reproduction and

linearity on T panels is poor. Shortcomings in display

color gamut(often referred to as a percentage of the TSC 195 color

gamut) are also due to bac lighting technology. It is not uncommon

for displays with simple LED or CCFL-based lighting to range from

10% to 6% of the TSC color gamut, whereas other ind of displays,

utilizing more complicated CCFL or LED phosphor formulations or

B LED bac lights, may extend past 100% of the TSC color

gamut, a difference quite perceivable by the human eye.The transmittance of a pixel of an LCD panel typically does not

change linearly with the applied voltage,[5]

and the s B standard for

computer monitors requires a specific nonlinear dependence of the

amount of emitted light as a function of the B value.

[edit]In-plane switching IPS)

In-plane switching was developed by itachi Ltd. in 1996 to improve

on the poor viewing angle and the poor color reproduction of T

panels at that time.

[6]

Its name comes from the main difference fromT panels, that the crystal m lecules m ve parallel t the pa el pla e

i stea f perpe icular t it . This change reduces the amount of light

scattering in the matrix, which gives IPS its characteristic wide viewing

angles and good color reproduction.[7]

Initial iterations of IPS technology were plagued with slow response

time and a low contrast ratio but later evolutions have made mar ed



improvements to these shortcomings. Because of its wide viewing

angle and accurate color reproduction (with almost no off-angle color

shift), IPS is widely employed in high-end monitors aimed at

professional graphic artists, although with the recent fall in price it has

been seen in the mainstream mar et as well.

Hitachi IPS evolving technology[8]

Name Nickname Year AdvantageTransmittance/contrast ratio

Remarks

Super TFT IPS 1996 Wideviewingangle

100/100 Base level

Most panels also support true 8-bit per channel color . These improvements came at the cost of a slower response time, initially about 50 ms. IPS panels were also

extremely expensive.

Super-IPS S-IPS 1998 Color shiftfree

100/137

IPS has since been superseded by S-IPS (Super-IPS, Hitachi Ltd. in 1998), which has all the benefits of IPS technology with the addition of improved pixel

refresh timing.

AdvancedSuper-IPS

AS-IPS 2002 Hightransmittance

130/250

AS-IPS, also developed by Hitachi Ltd. in 2002, improvessubstantially on the contrast ratio of traditional S -IPS

panels to the point where they are second only to some S-PVAs.

IPS-Provectus

IPS-Pro 2004 High contrastratio

137/313

The latest panel from IPS Alpha Technology with a wider

color gamut and contrast ratio matching PVA and ASVdisplays without off-angle glowing.

IPS alpha IPS-Pro 2008 High contrastratio

Next generation of IPS-Pro

IPS alphanext gen

IPS-Pro 2010 High contrastratio

Technology transfer from Hitachi to Panasonic

LG IPS evolving technology

Name Nickname Year Remarks

Super-IPS S-IPS 2001 LG Display remains as one of the main manufacturers of panels based on HitachiSuper-IPS.



Advanced Super-IPS

AS-IPS 2005 Increased contrast ratio with better color gamut.

Horizontal IPS H-IPS 2007

Improves contrast ratio by twisting electrode plane layout. Also introduces an optional

Advanced True White polarizing film from NEC, to make white look more natural.

This is used in professional/ photography LCDs.

Enhanced IPS E-IPS 2009 Wider aperture for light transmission, enabling the use of lower -power, cheaper

backlights. Improves diagonal viewing angle and further reduce response time to 5ms.

Professional IPS P-IPS 2010 Offer 1.07 billion colours (30 -bit colour depth). More possible orientations per sub -

pixel (1024 as opposed to 256) and produces a better true colour depth.

[edit]Advanced fringe field switching AFFS)

This is an LCD technology derived from the IPS by Boe- ydis of

Korea. Known as fringe field switching (FFS) until 00 ,[9] advanced

fringe field switching is a technology similar to IPS or S-IPS offering

superior performance and colour gamut with high luminosity. Colour

shift and deviation caused by light lea age is corrected by optimizing

the white gamut, which also enhances white/grey reproduction. AFFS

is developed by YDIS TEC L IES C .,LTD, Korea (formally

yundai Electronics, LCD Tas Force).[10]

In 00 , YDIS TEC L IES C .,LTD licensed its AFFS patent

to Japan's itachi Displays. itachi is using AFFS to manufacturehigh end panels in their product line. In 006, YDIS also licensed its

AFFS to Sanyo Epson Imaging Devices Corporation.

YDIS introduced AFFS+ which improved outdoor readability in 007.

In ay 011, this technology is reported to be used in the next

generation Amazon Kindle eboo reader.[11]

[edit]Multi-domain vertical alignment MVA)

ulti-domain vertical alignment was originally developed in 1998

by Fujitsu as a compromise between T and IPS.[citati

!

!

ee"

e"

]It

achieved pixel response which was fast for its time, wide viewing

angles, and high contrast at the cost of brightness and color

reproduction. odern VA panels can offer wide viewing angles

(second only to S-IPS technology), good blac depth, good color

reproduction and depth, and fast response times due to the use of

TC ( esponse Time Compensation) technologies. When VA



panels are viewed off-perpendicular, colors will shift, but much less

than for T panels.

There are several "next-generation" technologies based on VA,

including AU ptronics' P-MVA and A-MVA, as well as Chi ei

ptoelectronics' S-MVA. Analysts[w h

#

?]

predicted that VA woulddominate the mainstream mar et, but the less expensive and slightly

faster T overtoo it. The pixel response times of VAs rise

dramatically with small changes in brightness. Less expensive VA

panels can use dithering and F C (Frame ate Control).

[edit]Patterned vertical alignment PVA)

Patterned vertical alignment and super patterned vertical alignment

(S-PVA) are alternative versions of VA technology offered

by Samsung's and Sony's joint venture S-LCD. Developed

independently, they offer similar features to VA, but with higher

contrast ratios of up to 000:1.[citati

$ %

%

ee&

e&

]Less expensive PVA panels

often use dithering and F C, while S-PVA panels all use at least 8

bits per color component and do not use color simulation methods. S-

PVA also largely eliminated off angle glowing of solid blac s and

reduced the off angle gamma shift. Some newer S-PVA panels

offered byEizo offer 16-bit color internally .[citati

$ %

%

ee&

e&

], which enables

gamma and other corrections with reduced color banding. Some high

end Sony B AVIA LCD-TVs offer 10bit and xvYCC color support, for

example the Bravia X 500 series. PVA and S-PVA offer the best

blac depth of any LCD type along with wide viewing angles.[citati

$ %

%

ee&

e&

]S-PVA also offers fast response times using modern TC

technologies.

[edit]Advanced super view ASV)

Advanced super view, also called axially symmetric vertical

alig me t was developed by Sharp. It is a VA mode where liquid

crystal molecules orient perpendicular to the substrates in the off

state. The bottom sub-pixel has continuously covered electrodes,while the upper one has a smaller area electrode in the center of the

subpixel.

When the field is on, the liquid crystal molecules start to tilt towards

the center of the sub-pixels because of the electric field; as a result, a

continuous pinwheel alignment (CPA) is formed; the azimuthal angle



rotates 3 degrees continuously resulting in an excellent viewing

angle. he ASV mode is also called PA mode.[ ' 2]

[edit] isplay industry

Thi ( secti) 0

is missing citations or needs footnotes. Please hel1

add i 2 li2 e citati3 2

s t 3 guard agai 2 st

copyr ight violations and factual inaccuracies. (December 2008)

Due to the very high cost of building f actor ies, there are f ew

ma jor OEM panel vendors f or large display panels. he glass panel

suppliers are as f ollows:

L4

D glass panel suppliers

Panel type

Company Remarksmajor TV

makers

IPS-Pro Panasonic

Solely for LC5

TV

markets and known asIPS Al pha TechnologyLtd.[13]

Panasonic,Hitachi,

Toshi6

a

7

-IPS

& P-

IPS LG Display

They also produceother type of TFT

panels such as TN for

OEM markets such asmobile, monitor,

automotive, por tableAV and industr ial

panels.

LG,Phili ps

S-IPS

Hannstar

Chuangwa Picture Tubes,

Ltd.

A-MVA AU Optronics

S-MVA Chi Mei Optoelectronics

S-PVA S-LCD (Samsung/Sony joint venture)

Samsung,

Sony

AFFS SamsungFor small and medium

si8 e special projects.



AS9

Sharp Corporation

Solely for LCD TVmarkets

Sharp

Raw LCD TFT panels are usually factory-sorted into three categories,

with regard to the number of dead pixels, bac light evenness andgeneral product quality.

[citati @ A

A

eeB

eB

]Additionally, there may be up to +/-

ms maximum response time differences between individual panels

that came off the same assembly line on the same day. The poorest-

performing screens are then sold to no-name vendors or used in

"value" TFT monitors (for example, mar ed with letter V behind the

type number), the medium performers are incorporated in gamer-

oriented or home office bound TFT displays (sometimes mar ed with

the capital letter S), and the best screens are usually reserved for use

in "professional" grade TFT monitors (often mar ed with letter P or Safter their type number).

[edit]Electrical interface

External consumer display devices li e a TFT LCD feature one or

more analog V A, DVI, D I, or DisplayPort interface, with many

featuring a selection of these interfaces. Inside external display

devices there is a controller board that will convert the video signal

using color mapping and image scaling usually employing the discrete

cosine transform (DCT) in order to convert any video source

li e CVBS, V A, DVI, D I etc. into digital RGB at the native

resolution of the display panel. In a laptop the graphics chip will

directly produce a signal suitable for connection to the built-in TFT

display. A control mechanism for the bac light is usually included on

the same controller board.

The low level interface of ST , DST , or TFT display panels use

either single ended TTL 5V signal for older displays or TTL . V for

slightly newer displays that transmits Pixel cloc , orizontal

sync,Vertical sync, Digital red, Digital green, Digital blue in parallel.Some models also feature input/display enable, horizontal scan

direction and vertical scan direction signals.

ew and large (>15") TFT displays often use LVDS signaling that

transmits the same contents as the parallel interface ( sync, Vsync,

RGB) but will put control and RGB bits into a number of serial

transmission lines synchronized to a cloc whose rate is equal to the



pixel rate. VDS transmits seven bits per clock per data line, with six

bits being data and one bit used to signal if the other six bits need to

be inver ted in order to maintain DC balance. ow uality displays

often have three data lines and theref ore only directly suppor t bits

per pixel, while better ones have a f our th data line so they can suppor t24 bits per pixel, which delivers truecolor . ltra high end models can

suppor t even more colors by adding more lanes, that s how 3 -bit

color can be suppor ted by five data lanes. Panel manuf acturers are

slowly replacing VDS with Internal DisplayPor t and Embedded

DisplayPor t, which allow sixf old reduction of the number of diff erential

pairs.

Backlight intensity is usually controlled by varying a f ew volts DC, or

generating a P M signal, or ad justing a potentiometer or simply fixed.

his in turn controls a high-voltage .3 kV) DC- AC inver ter or a matr ix of EDs. he method to control the intensity of ED is to pulse them

with P M which can be source of harmonic flicker .

he bare display panel will only accept a digital video signal at the

resolution determined by the panel pixel matr ix designed at

manuf acture. Some screen panels will ignore the SB bits of the color

inf ormation to present a consistent inter f ace bit->6bit/color x3).

laptop displays can't be reused directly with an ordinary computer

graphics card or as a television, this is because they lack a hardware

rescaler that can resi e the image to fit the native resolution of the

display panel.[c it C tion n

D D d D d ]

ith analogue signals like VGA, the display

controller also needs to per f orm a high speed analog to

digital conversion. ith digital input signals like DVI or HDMI some

simple reorder ing of the bits is needed bef ore f eeding it to the rescaler

if input resolution doesn't match the display panel resolution. or

CVBS V) usage a tuner and color decode f rom a uadrature

amplitude modulation QAM) to uminance Y), Blue-Y ), Red-Y

V) representation which in turn is transf ormed into Red, Green Blue

is needed.[c it C tion n D D d D d ]

[edit]Saf ety

This section requires expansion.

[edit]Toxi ity



The liquid crystals inside the display are highly toxic to humans and to

the environment. It must not be ingested or come in contact with your

s in, eyes or clothes. If spills occur due to a crac ed display, wash off

immediately with soap and water.[1

E

] Liquid crystals currently

mar eted inside displays are generally non-toxic

[15]

.[edit]



TFT stands for Thin-Film Transistor. TFT technology is a new standard these days for

manufacturing displays, monitors, laptop screens, and other devices. TFT LCD displays can

show crisp text, vivid colors, fast animations, and complex graphics.

TFT LCD monitors, also called flat panel displays, are replacing the old style cathode ray

tubes (CRTs) as the displays of choice. Almost all LCD monitors today take advantage of the TFT technology.

What are the benefits of a TFT display?

Each pixel on a TFT display is backed by a tiny transistor. Transistors are so small these

days, they need only a very minimal charge to control what they do. TFT displays are much

more energy eff icient than regular CRT screens that need a powerful light source.

TFT displays also allow for very f ast re-drawing of the display, so the image has very

little chance to flicker. This was not always the case with flat-panel monitors. Original

passive matrix LCD displays were not able to refresh at very high rates and therefore could

not keep up with fast moving images. A TFT monitor refresh rate is very high resulting in a

display that can be used for video, gaming, and all forms of multimedia.

A TFT monitor delivers crisp text, vibrant colors , and an improved response time for

multimedia applications. Today's standard for response rate in TFT monitors is 16 ms or

less.

H ow does TFT display work?

Let us start with explanation how a LCD display, a predecessor to TFT LCD, works.

In general, a LCD display comprises of a layer of LCD material and one or more polarizinglayers made of plastic, glass, or some other material. A LCD display has a sandwich-like

structure with liquid crystals filled between two glass (or plastic or polycarbonate) plates.

A LCD display shows a picture through millions of tiny picture elements called pixels. You

can understand a pixel as a tiny dot on your screen.

Pixels are formed by liquid-crystal cells that change the direction of light passing through

them in response to an electrical voltage.

These liquid crystals when stimulated by an external electrical charge can change the

properties of light passing through them. When you align two polarizing materials witheach other, light passes through. When you align one polarizing agent at a 90° angle to the

other, light is blocked. Change the voltage, and the amount of light passing through the

display is changed.



Liquid crystals in LCD monitor act as a dynamic polarizing agent. They change their

orientation when you place a voltage across an LCD cell. The orientation of the polarizing

agent under the LCD layer either blocks or pass es light.

So, where does a TFT come into the game?

A TFT display is an advanced LCD display. A TFT monitor uses so -called thin-f ilm

transistortechnology to project a picture on the screen. Transistors in a TFT display are

used to change the orientation of the polarizing agent. A typical 17-inch TFT monitor has

about 1.3 million pixels and 1.3 million transistors. The following text explains TFT in a

greater detail...

Active or passive LCD?

When you look at a passive-LCD technology, the cells act as capacitors. When you charge acell, the liquid crystal flips to one position. When you stop supplying charge to the cell, it

voluntarily bleeds off its voltage and the liquid crystal slowly twists back to its original

position.

Passive LCD panels cannot quickly change the orientation of the crystal. Well, it is quick,

but not quick enough to display fast -moving graphics. To overcome this slowness,

engineers came up with active-LCD technology. Active-LCD displays use transistors to

actively change the orientation of crystals. That is where TFT comes from. T in TFT for

transistor. This method allows for faster control of the LCD cell but is also more complex.



While passive-LCD displays start to blur with images moving faster than 8 to 15

frames/sec, TFT displays can display full-motion video and graphics because they use fast

switching transistors.

H ow is color displayed in a TFT monitor?

Now that we know how a LCD works and what it behind TFT, we can start talking about

color. Each pixel in a color TFT LCD i s subdivided into three subpixels . One of the subpixels

is capable of producing red, the other one green, and the last one bluecolor. Red, green,

and blue are the basic colors. Any other color can be produced by mixing up these three.

One set of RGB subpixels is equal to one pixel.

Because the subpixels are super tiny for the human eye to see them individually, the three

RGB elements appear to the human eye as a mixture of the three colors. Any color can beproduced by mixing these three primary color s.

Where does the light in a TFT LCD panel come from?

Old TFT displays and the small ones in simple applications such as calculators are ref lective

TFT. A reflective TFT display has no backlight. The polarizing agent at the rear of the TFT

display is simply a mirror layer behind the TFT panel. The agent merely reflects incoming

light from the front of the display. You need to be in a well -lit room to be able to read this

type of display.



The next step in a TFT LCD design was to add a light source to it. More advanced TFT

displays have added sidelights or front lights to these displays. Sidelights and front lights

are virtually the same as backlights. The difference is just the position of the light. Front

lights sit on the side or slightly in front of the TFT layers. They are designed so that the light

they produce shines through the TFT panel and bounces off the reflective polarizing agent

back through the display.

A transmissive TFT uses a backlight. Most TFT LCD panels today are designed with

a backlight. The source of the light is mounted at the rear side of the LCD panel and shines

light towards your eyes through the TFT panel's polarizing medium (liquid crystal). Small

displays, such as cell phones or calculators, use light source that is placed along the sides of

the display.

The common TFT-display backlight is the CCFL (cold -cathode fluorescent lamp). CCFLs are

similar to fluorescent light tubes that you commonly find in offices and homes. Their

advantage is that they are small, inexpensive, replaceable, and cheap.

If the TFT display has its own light, why can't I see anything

on the display on a sunny day?

The polarizing medium in a TFT that transmits or blocks the backlight is clear, so any light

shining on the display from the front competes with the backlight. If the light source



shining on the front of the TFT display is strong enough, such as sun on a sunny day, it

simply overpowers your laptop TFT display's backlight and the display image is washed out.

A reflective TFT display is usually a better choice for applications with high ambient light.

What is LED backlighting in a TFT LCD display?

If you shop for a laptop these days, the better ones come with LED backlight. In this case,

the source of light comes from LEDs instead of from CCFL.

LED technology has only recently achieved the white light necessary to illuminate these

panels. LEDs are the choice these days because they are stable over temperature ranges,

durable, and very energy efficient. That is why if you buy a laptop with a TFT LED b ack-

lighted display, it is possible that it will go for as much as 8 hours with your battery.

What else?

Perhaps you might be interested in some reading about LightScribe, ExpressCard, or USB

3.0 (Need for speed).



T hin F ilm T ransistor is a variant of liquid crystal display (LCD) which uses thin-film transistor (TFT)

technology to improve image quality (e.g., addressability, contrast). TFT LCD is one type of active

matrix LCD, though all LCD-screens are based on TFT active matrix addressing.

Advantages of TFT displays over traditional CRT monitors:

There is much less glare from a TFT monitor. During testing in the Arts IT office we were able to have

the blinds open and still read the screen, something impossible with CR

T displays.The monitor is less bul

F

y. This has a couple of advantages, firstly it gives you more desF

space, but

secondly because of this you can position the monitor further away from you which we have found

more comfortable for the eyes.

TFT monitors produce less heat and radiation that CRT monitors.

TFT monitors have a very crisp image only comparable to very expensive CRT monitors.

The monitor (so long as it is VESA compliant) can be mounted on an arm or on the wall to save even

more desF

space.

Disadvantages of TFT displays:

If you are wor F

ing with graphics, although the graphics are very clear, due to the limited angle at

which you can view the display colours may appear slightly different on non-TFT screens. Web

authors beware.

Cost. A 15" TFT monitors costs approx £ G 50+vat for an unbranded/cheap model. A 17" CRT monitor

costs approx £1 H 0+vat.

TFT monitors have a limited angle of view. This is the angle at which you can clearly view the screen.

If you are looF

ing directly at the screen while wor F

ing on your PC this is fine, but if others are trying to

read it then they may have difficulty (try looF

ing at a laptop screen from a I 5 degree angle).

You may experience some blurring on lower end models when there is movement on the screen. This

is most prominent in full screen games where you get a motion blur effect but is also noticeable when

scrolling through documents or websites.



TFT vs CRT monitor comparison

February 2, 2008 - 11:30 ² webmaster

Quite a lot of our customers these days go for TFT monitors when they buy their computers. Most

buy their TFTs because they look better than CRT monitors and because the price differentials are

much lower than what they used to be. We try our best to convey to our customers the differences

between CRTs and TFTs and the specific scenarios when one is better than the other. Some timeswe get through and some times we don't. Here we would like to bring out the differences between

the two types of monitors and their pros and cons.

Traditionally all computer monitors used to be CRT monitors which are quite similar to the CRT

televisions we have in our homes. LCD monitors were only used with laptops as the price

differences were quite high. However as technology advanced and the price differences between

CRTs and TFTs came down it became viable to sell computers with TFT (or LCD) monitors. The

display device in a CRT monitor is a cathode ray tube which is inherently bulky and power-thirsty

whereas the display device in a TFT monitor is a flat array of Thin Film Transistors which makes

the TFT monitors much smaller in size and also less power consuming.

The major differences between the two are

1) CRT monitors are bulky and consume a lot of table space where as TFT monitors are thin and

occupy less space.

2) TFT monitors are more easy on the eyes of the viewer than CRT monitors.

3) CRT monitors have much much faster response times than TFT monitors. Response time is the

time interval taken by a pixel on the screen to transit from the on state to the off state or reverse.

4) TFT monitors consume less power than CRT monitors. A typical 15" CRT monitor consumesabout 100W of power whereas a corresponding TFT monitor would only consume 30W of power.

5) TFT monitors looks more elegant than CRT monitors.

6) CRT monitors tend to have much better color responses than TFT monitors. In other words CRT

monitors display colors much better than TFT monitors.

Based on the above differences we can easily make certain deductions about the scenario's where

each of these types of monitors are ideal.

1) You save 70W when you use a 15" TFT monitor instead of a 15" CRT monitor. This would

translate to around 1 unit of electricity every 14 hours of usage. So depending on your usage

patter you can see how long it would take to break even on the cost differential through energy

savings. Say 1 Unit of energy costs 8 Rupees (approx 20 cents) and the cost differential is Rs 4000

(approx 100$) and you use your monitor for 10 hours every day, you will break even in around

700 working days. The equation used is simple; No of days for breaking even = ((Cost

Differential/Cost per unit)*14)/(Hours used per day). Based on your usage pattern and your

budget you can use the above data to make an educated decision.



2) If you are a graphics artist and you require close to realistic representation of colors you will

have to go for a CRT monitor irrespective of any other factors.

3) If you are a gamer then depending on the type of games you play you will have to choose

between CRT and TFT monitors. If you play very fast moving games then response times of the

monitors comes into play and you might end up having to buy a CRT monitor to get a smoothgaming experience. If however you play more strategy games than action or racing games then

depending your other usage patterns you can decide between either a TFT or a CRT.

4) If you have to move your residence frequently as part of your job and you have to have a

desktop, then a TFT monitor would make more sense. It should be noted that a laptop would make

even more sense in such cases.

5) If you are running a software development center it might be wiser to select TFTs for your

software developers and CRTs for your graphics guys. If you are running any other kind of office

where your computers remain on most of the day then TFTs would pay for themselves in a few

years and would be the ideal choice.

6) If you are running a retail outlet a TFT would give your POS counter a more professional look

and also help you save on your electricity bills.

7) Small or restricted work areas also place a default preference of TFT monitors over CRT

monitors.

If you need help in deciding between a TFT monitor or a CRT monitor, do get in touch with us

using the comments form below and we will try to help you in making your decision.



Q: What is a TFT?

A: Short for Thin Film Transistor, a type of LCD flat-panel display screen, in which each pixel is

controlled by from one to four transistors. TFT screens are sometimes called active-matrix LCDs.

Q: What are the benefits of a TFT display?

A: A TFT LCD display delivers crisp text, vibrant color and an improved response time for visual

applications at the best resolution of all the flat-panel techniques, but it is also the most expensive.

Q: What sets the TFT apart for other LCDs?

A: TFT displays use a separate tiny transistor for each pixel on the display. Because each transistor is so

small, the amount of charge needed to control it is also small. This allows for very fast re-drawing of the

display, as the image is re-painted or refreshed several times per second.

Q: What are the differences between TFT and Color STN?

A: TFT displays utilize active matrix technology and feature transistors on every pixel. Color STN (CSTN)

is a passive matrix graphic LCD with a color filter. It only has one transistor per each pixel row and

column and features a lower refresh rate than TFTs.

Q: What size TFTs does Microtips currently offer?

A: We currently offer a 2.4´, 2.8´, 3.5´, 4.3´, 5.7´ and 7.0´ TFT.

Q: How do I interface with a TFT?

A: 1st Pick a microprocessor with a built-in TFT controller (this will tell you which interface type to use)

2nd Determine which TFT size and interface type required

3rd Determine how the pins on the TFT should best connect to the corresponding pins on the your

microprocessor

4th Connect the FFC from the TFT to a mating connector mounted on your board which is assigned to

the TFT interface of the microprocessor

5th Write initialization code and software through your microprocessor to the TFT

Q: How does Microtips handle a fluctuating TFT supply chain? A: Microtips utilizes strategic partnerships with our supply chain and focuses on standard TFT sizes

(3.5´, 5.7´, and 7.0´).

Q: Who drives the TFT market?

A: The small TFT displays below 3.5´ are typically driven by the large volume cell phone manufacturers

in Asia. That being said the supply chain for TFT displays below 3.5´ can be more volatile than the 3.5´

and above sizes. The digital photo frame industry has also begun to affect the availability of the 7.0´ and

5.7´ sizes.

Documents

Thin Film Transistor Liquid Crystal Display