LCD Monitor buyer’s guide

Posted Jun 10, 2009
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Today we are going to embark on a journey that we have traversed for all our life. However, if we do not, or can not, truly appreciate the essence of its thrill; we are missing the whole point. That means, the promises of our LCD screens is under scrutiny today.

What’s wrong with the good ol’ CRTs?

Everything other than picture quality, refresh rate and color reproduction!
The world has stuck with CRTs for not a decade or two but for 4 grand decades. Even our eyes are tuned to watch movies through CRTs. Disadvantages being the most obvious size, weight, power consumption etc, basically the things we all know.

So newer is better?

LCDs have improved upon the obvious cons of CRTs but with an added baggage of their own newly introduced problem set. Very early on in their lifetime, you used to count the dots aka pixels on the panels. Even now, sitting close to computer monitors bigger than 22” you can witness the dot phenomena of LCDs. The reason behind this is that LCD (Liquid Crystal Display) comes with a pre-specified native display resolution with the manufacturer cramming exactly this much number of liquid crystals into that panel. Therefore a bigger panel with small native resolution makes you spot the crystals distinctly. This problem is almost gone for newer panels.

The HD experience!

About the resolution, there is that hype of HD experience. This high definition stuff requires the display to have either of these resolutions 720p, 1080i, 1080p. For us techies, 1280 * 720 is 720p while 1080 refers to the 1920 * 1080 resolution. This is a wide viewing angle resolution of 16:9 aspect ratio. HD also requires signal input through HDMI connection. This connection transfers both the video and the audio signals all digitally; no digital to analog conversion going on. There is that alternate signal connection called DisplayPort that promises to transfer signals beyond HD quality requirements. However, you need to have the same type of connection on both the video card and the LCD. Trends show that consumer electronics are bent towards HDMI while computer devices are interested in using DisplayPort connectors.

On the other hand, our wide viewing angled LCDs monitors typically have 16:10 aspect ratio. 24” LCDs have 1920 * 1200, 22” have 1680 * 1050 and so on. These LCDs can display HD resolutions 1080p and 720p respectively but with degraded experience of black bars at top and bottom of the movies. Newer panels for the year 2009 are going to be 16:9 aspect ratio and they will be cheaper.

Display Port, HDMI, DVI-D
Figure 1: DisplayPort, HDMI & DVI-D in one [Click to enlarge]

In Figure 1 you can clearly see the three kinds of connectors on this newly launched Dell 2408WFP model. The same connectors are also found on various graphics cards.

How fast are my crystals?

Another one is the response time problem. This one matters a lot for gamers. In order to display frames, each and every crystal of an LCD physically rotates to change the colors. This physical problem causes manufacturers to improve and report all sorts of specs regarding response times. You hear of 2ms GtG or 10ms ISO time. That means it takes 2 milliseconds for a crystal to change color from one gray shade to another or 10 milliseconds to change color according to ISO spec. Now, ISO spec implementation varies among different manufacturers. Whatever the case may be, this time should be lesser than 10 ms.

A very similar concept is the Response Time Compensation for a monitor. We are the generation who are witnessing the expiration of CRT (Cathode Ray Tube) technology. We remember the flickering of the frames to displaying a video on our CRT monitors. It seems particularly ugly when you shoot a video of any movie running on your CRT. To make matters worse, this flickering is needed for our eyes. If there is no black out between frames and there is a continuous stream of frames then we’d see frames blurring. This is because the image of one frame is not completely washed out from our retinas before the other frame displays, yielding the blur. There is no such thing as refreshing in LCDs so the black out gaps are artificially introduced. Early generation RTC technology had its share of errors but now things are getting smoother in the latest generation of Samsung.

Contrast my brightness

Contrast ratio basically refers to the ratio of the pure white to the pure black of a screen. These ratios are drastically inflated in the recent models under the label of dynamic contrast technology. This is in fact another duct tape kinda solution by introducing software based contrast variations. For a naked eye, there is very little difference among the ones that have it and the ones that don’t have it.

Moreover, LCDs with LED backlighting produce brighter and richer colors.

Pixel Pitch refers to the concentration of the crystal in a square inch, or whatever, it basically is a measure of the crystal density. [Doesn’t help at all in judging the quality of the LCDs]

Look straight into me eyes

Viewing angle problem is another pain in the @$$. There are certain panels that provide very good angles but bad response times. Whatever the case may be, if you place the LCD above your eyes level and look at it from below, it always sucks.

Older is cheaper!

Now comes the real deal. Which panel type is the best? There are 3 kinds of panels in common use today: TN matrix, PVA and IPS panels. TN matrix is the most common, cheapest and has worst viewing angles but good response times. PVA & IPS panels have very few differences between them and they are expensive with good viewing angles. Their downside of bad response times are really improved with the use of the RTC technology. However, these panel types are hardly found on LCDs smaller than 24”.

Some monitors come with glossy surfaces. This attracts dust a lot and reflects side lights as well but in a totally closed room it produces very good images. Another hot topic for discussion regarding panel types is the S, A and C panels. They are the three panel manufacturers that Samsung engages for the production of its panels. S stands for Samsung, A for AU Optronics (AUO) and C for Chi Mei Optoelectronics (CMO). But of course best ones among them are the S panels then C then A, albeit minor differences. Its hard to tell them apart but the only way to do this is to look at the complete model number and search it on the internet for details.

eXtras

There are other bells and whistles attached to LCD monitors nowadays. Side speakers and the recently introduced surround speakers are very easy to spot. One Samsung monitor even attached a second mini-LCD with one of its model. Touch sensitive controls is also available on some models. However, it depends on your needs in order to make a purchasing decision.

Brands

Lastly, we have the brands to choose from. Samsung, Asus, Dell, Acer, BenQ and NEC are all good brands to name a few. Just know your current and future needs, watch your budget and pick any wide angle LCD monitor.

Bibliography

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