Features of LCD Monitors
September 23, 2009
LCD monitors come in different sizes and resolutions. There are certain things that have to be kept in mind while purchasing an LCD monitor. Let us go through some of those criterions that determine the quality of LCD monitors.
The foremost thing to be considered while buying LCD monitor is its native resolution. LCD monitors, when compared with the conventional CRTs, displays images only at a particular resolution, which is known as the native resolution. These monitors display each pixel using a horizontal and vertical matrix of dots. Typical resolutions of LCD monitors are 1024 x 768 for 17”, 1280 x 1024 for 19” and 1600 x 1200 for 20” LCD monitors.
The second thing that has to be kept in mind is the viewing angle. Different monitors have different viewing angles. Generally, it is seen that viewing angles varies between 120° and 170°. The third feature of an LCD monitor is its brightness. It is the measure of light, which the monitor generates. Its unit is in candela per meter square. Normally, it ranges from 50 to 350cd/m2.
The contrast ratio is the fourth feature. It is the ratio between the darkest and most white spot that appear in the display. Response rate indicates the speed of the display in changing through different colours. It is recommended to have a faster response rate in order to reduce the ghosting effect. If higher is the response rate, better will be the pleasure in gaming and watching movies.
Adjustability is the last feature to be discussed. LCD monitors provide more flexibility to position the screen in the way we want it to be. The screen can be tilted and even rotated to horizontal or a vertical plane. Moreover, it has built-in brackets to facilitate wall mounting. Apart from these, LCD monitors are provided with integrated speakers, USB ports and anti-theft locks.
About LCD monitor technology
July 24, 2009
LCD monitor technology is the latest and it varies from a CRT monitor. You should be aware about how LCD technology works, as this will help you make a better judgement when you buy an LCD monitor. In short, LCD works by having liquid crystal panel filter light from an incandescent lamp. However, there is much more to know about the technology.
It is through the involvement of polarisation of light that LCD manages the course of light. As soon as the light is polarized at a particular angle of polarization, using a filter you will be able manage the strength of the light by means of altering the polarization angle of a different filter.
Passing of the light through a polarizing filter is the initial stage of an LCD display. The light gets further hooked on a layer which is packed with liquid crystals and it is the transistors that control them. Soon after that, the light is passed into colour filters. The spatial alignment of the liquid crystals is set when the transistors applies voltage to it. The angle of polarization of the light is changed when it is passed through the well-organised liquid crystal molecular structure and with regard to its latest angle of polarization, it will be ed up either partially or completely. It enables any halftone creation from black to pure white.
Three types of LCD displays
There are 3 types of LCD display which includes TN TFT or TN+Film TFT (Twisted Nematic + Film), IPS (In-Plane Switching) and MVA (Multi-Domain Vertical Alignment.
TN TFT technology
TN TFT or TN+Film TFT (Twisted Nematic + Film) is the most popular digital panel technology. The supplementary external film covering is known as the “Film”, which results in the increase of usual 90 degrees viewing angle to 140 degrees. TN TFT is known as the 1st LCD technology and is popular even today, when compared to the low end panels on laptops and desktops.
Low manufacturing expenses is the main reason behind this. However, there are few disadvantages of TN TFT matrix based LCD panels. Poor contrast is offered as the black colour appears dark grey in old panels, which is one of the main drawbacks. With the advancement in this technology, improved TN panels are able to display dark shades of grey to black. A bright “dead” pixel comes into view when a transistor expires and they are more visible than the black “dead” one.
IPS (In-Plane Switching)
To sort out the drawbacks of TN TFT technology, a new IPS (In-Plane Switching) technology was developed. It is also known as Super-TFT and Hitachi is given the credit for developing this technology. With this technology, the viewing angle could be increased to 170 degrees, which was made possible by utilising a more accurate means of controlling liquid crystals alignment that proves as its main accomplishment. On the other hand, the response time grew higher and the contrast ratio remained the same as in TN TFT panels.
The good part of this technology is that, the dead pixels will fade to black rather than bright white of the TN TFT panels. The disadvantage in this technology is that, the management of electric field require more energy and takes additional time. This in turn, increases the response time. These are not ideal for mobile applications.
MVA (Multi-Domain Vertical Alignment)
MVA technology was developed by Fujitsu and they are descendant of previous VA technology. It is developed to eliminate all the problems faced by LCD panels. The plus point of this technology lies on its improved viewing angle and enhanced colour reproduction, which is offered by splitting the colour elements into cells or zones. On an internal surface filters, these are created by ridges. The basic idea for developing this technology was to facilitate the movement of liquid crystals in the reverse route to their neighbours. With this viewer, one will be able to view the identical hue regardless of the viewing angle.
Reduced response time is yet another plus point of MVA technology. On the other hand, the intricate panel layout increases the cost and at the same time, the manufacturer fails to utilise all the MVA benefits mainly because of technological problems and complex manufacturing process. At present, MVA is the improved technology, but grows at a steady rate.
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