How TFT's Work

 

Panel Manufacturers
How TFT Technology Works
LED backlighting

OLED Displays

DisplayPort
CableComp

Faroudja Video Processing

 

 

 

 


Panel Manufacturers

 

While there are many different manufacturers of TFT monitors, there are several main manufacturers of the panels themselves incorporated into these screens. The main manufacturers in today’s TFT market are

 

 

AU Optronics (AUO)

Samsung

LG.Display (LGD)
Previously known as LG.Philips (LPL)

Sharp

BOE Hydis (BOE)

Hitachi

Chi Mei Optoelectronics (CMO)

Chunghwa Picture Tubes (CPT)

NEC

ID Tech

HannStar

S-LCD
(Samsung+Sony Joint Venture)

            
 

These manufacturers produce a wide range of panel technologies and of differing specs, and source their panels to the monitor manufacturers. See also:

- TFT Central Panel Search - find out which panel is used

- dsnavigator - Panel Spec List

- Horizon Technology - Panel model numbers and links

- Prad.de - German site, but good TFT news. Also panel and spec checking

 

 


How TFT's Work

Tom's Hardware provide a good guide to how the TFT monitors work. Another resource which is good comes from one of the biggest panel manufacturers in the world,  and AU Optronics provide a good background to LCD / TFT technology here. There is a lot of information around on the net about the electronics and specifics of TFT technology so I won't re-hash it too much here.

 

 


LED backlighting

 

Traditional CCFL backlighting has been replaced in some models by LED backlighting. This is a new technology, but is designed to offer a few improvements over conventional methods. These include improved panel uniformity, improved life expectancy, and because LED’s are capable of producing whiter whites, the colour fidelity should be improved. Look for models which specifically state that they are LED backlit.

 


Organic Light Emitting Diode (OLED)

This technology was invented in the 1980's. The pros of OLED technology are: Since it is a light emitter, it creates light that is Lambertian so it can be seen uniformly at all angles and gives a very pleasing effect. Wide viewing angles are a key feature of these displays. The biggest strength of OLED's is that they do not require a backlight and can be made thinner than any other technology used today. A 2 mm thick OLED is a reality today where the thinnest LCD is 3 mm.  With no backlight, lighting of the panel is uniform, and they are designed to offer higher brightness and contrast ratios. They will also require less power to operate as they do not need backlighting. They are cheaper to produce than LCD's because they use less materials and the polymers can be "printed" onto plastic or glass sheets using a process similar to inkjet printing. Theoretically, they will be cheaper to produce and so should be cheaper to buy. There are some drawbacks to the technology however:

 

·         Dynamic display efficiency. While you can write a few lines of static text with great efficiency, video requires more power than an LCD. OLED's are more efficient for small graphics or text because they only consume power in the area where they are addressed. To date, the reliability has not come up to the levels of LCD's. It is particularly difficult to drive the blue colours where the luminance efficiency is very low. As a consequence, the lifetime is reduced, and burn-in is also an issue. Red and green colour polymers are apparently sturdy enough, but problems with the blue colours are a hurdle at the moment.

 

There is a more detailed article about the technology here on Sharp's and AU Optronics' websites:
 

http://www.sharpsma.com/lcd/lcdguide/Technologies/OLED_displays.php

http://www.auo.com/auoDEV/technology.php?sec=OLED&ls=en

 

OLED displays are not likely to be widely used in the TFT desktop market, and will likely be more aimed at large TV’s and Hi-Def displays. These probably won’t emerge until 2007 as well, and will likely be very pricey. However, it is an emerging technology, which I think is worth mentioning.

 

 


DisplayPort

Together with other leading video companies like ATI, NVIDIA, Philips and Samsung, Genesis have proposed a new high bandwidth digital interconnect standard. This is designed to greatly simplify connectivity for streaming media from one system to another. It allows streaming of up to 6 High Definition TV Channels simultaneously in the same number of wires that current cables use to only stream 1 channel. Further information about DisplayPort can be found here:

 

Overview: http://gnss.com/technology/DisplayPort Overview White Paper.pdf

Technical: http://gnss.com/technology/DisplayPort Technical Overview White Paper.pdf


 


CableComp Technology

NEC have introduced their "CableComp" technology which automatically compensates for signal quality differences caused by long cables and weak signals. The technology allows you to use cables of up to 20m and still support the 1600 x 1200 resolution over DVI. This is as compared with normal operation of about 7m. For 1280 x 1024 resolution on DVI you can use cables up to 30m in length, and for VGA / Analogue connections, up to 100m! This is achieved through the use of a booster and intermediate replicater, and does not lead to any delay either.


 


Faroudja Video Processing Technology

 

This technology was developed by Faroudja, a subsidiary of Genesis who manufacturer monitor controller chips. The technology consists of a suite of enhancement algorithms designed to improve image quality. These include:

 

See the following article for more information: Faroudja Video Processing and Genesis Controller Chips