by Lee Koo (ADMIN) - 12/15/05 2:44 PM
A CRT flat-screen monitor not only has a much larger viewing
area and resolution rate, it's a lot cheaper than comparable
LCD monitors. Other than size and style, what are the
advantages and/or disadvantages of using an LCD monitor over
a CRT monitor? And if I were looking into purchasing an LCD
monitor, are there any specific things, such as contrast
ratios, refresh rate, and so forth (which is all foreign to
me), that I should pay particularly close attention to in
order to make a good buying decision on an LCD monitor? I
would be grateful for any detailed explanations. Thanks.
Submitted by: George
Let's try to help you decide what type of monitor to buy. I will try not to sway you one way or the other; however, LCD monitors show obvious advantages, while CRT do not. For reference, LCD stands for liquid crystal display, which uses two sheets of polarizing material with a liquid crystal solution in between. When electric current passes through the solution, it causes the crystals to align themselves so that light can't pass through them. Each crystal is like an on\off switch--either it allows light to pass through or blocks the light.
CRT is cathode ray tube, and uses an electron beam which passes back and forth on your screen. It lights up the phosphor bits, or dots, inside a glass tube that essentially lights up any active portion of your screen, giving you an image. NITS is used to describe LCD brightness; the higher the NIT, the brighter your display.
That said, let's look at some things to consider.
Benefits and non-benefits of both...
There are essentially many benefits of LCD beginning with, what in my eyes is most important - ELF \VLf, which goes under electromagnetic radiation emissions in CRT caused from the scanning beam. LCD does away with this.
This was also the reason for many glare screens on CRT monitors. There is a counterpart to this - the flicker you get from the refresh rate on CRT which causes symptoms such as eye strain, headaches, motion sickness and is called computer vision syndrome. This is caused by the scanning beam that refreshes your image, along with glare, position of monitor etc... LCD does away with this also, and as I mentioned above (each pixel acting as an on\off switch on LCD), is what eliminates the flicker problem with CRT. Also, the eye fixation is less; in a couple of words, your eyes have less to fix themselves on with LCD contributing to less CVS also. There are studies being done to see how much CVS is being reduced by using LCD monitors. As far as GLARE is concerned, it is fairly done away with as LCD uses a plastic film instead of glass to reduce glare.
There are however, many factors to be looked at. The length of time you use a monitor has a lot to do with many of the problems mentioned and does not mean that a CRT monitor will cause any of this immediately, in the future, or at all. Some claim to never have had issues, while others do.
Another consideration is energy consumption. A "typical" LCD monitor will use about 25 to 30w when in use and when in standby, around 3 to 4w. A CRT monitor will use 80w in use and around 5 w in standby. One thing to look at is a 15" LCD may give you close to the viewing area of a 17" and a 17" LCD will be close to a 19" CRT monitor, so getting a smaller LCD gives you a larger CRT viewing area, reducing the wattage in size. This can be a huge energy saver over years for anyone. This will also help to possibly balance the price difference in LCD to CRT, which I will get into later.
There are also angle viewing concerns. Most CRT monitors can be viewed from a sharp angle while LCD cannot. This means, if you (let's say at work) for whatever reason need to work from the side for a moment, you may have a hard time viewing your work screen with LCD. However, LCD is far more adjustable on the pivot arm than CRT and many times can make up for the lack of angle viewing. Many companies are solving this issue also and it is no longer a problem for some, but others like the screen viewing privacy this gives, so fixing this may not be good for some.
Straight on viewing in LCD is geometrically better since it lacks the distortion of CRT and your screen view is focused, you see your whole screen, and portions are not lost or out of proportion. This is the reason a 15 " LCD may give you close to a 17" CRT display. To put it another way, all your pixels are fit within a certain range on your screen so you get the whole view without distortion.
Refresh rates in LCD have surpassed or equaled CRT. There were many issues with GHOSTING on the screen, which when playing a movie, or high end video game, left an image behind itself when movement occurred. Many LCD companies have solved this issue also.
Your DOT PITCH is the space between pixels. The smaller your number (e.g. 0.34 to 0.24) the 0.24 would be a better display. This is something to keep an eye on when buying a monitor. Newer CRTs will give you a resolution of up to 1600 X 1200 and higher. One drawback of most LCDs - the native resolution is a set resolution and can be changed, but you may get quality loss and performance loss. This is also being worked on and will not be an issue in the near future. Some still say that LCD cannot surpass the color depth of the CRT, but that is changing also. In general, an LCD will be up to any lacking that a CRT can provide. For a typical user, the color depth will not be an issue as it comes into play with graphic artists and such.
EMI (electro magnetic interference is still an issue with CRT. For example, speakers too close to the monitor will cause distortion, green or white patches, among others. LCD is not affected by EMI (in most) and has protected circuits, so it is covered from EMI. Some very cheap brands do not use protection, or use low protection, on their circuits, but this is rare. While extremely high EMI's may still affect an LCD, in most cases it is no longer a concern.
CRTs were known for having a sharper, true color image, but with active
matrix display, the LCD refresh rate is higher than on most CRTs. The technology has a price currently, but active matrix, in my opinion, will become a standard and the price will narrow.
Space is a major factor also. A typical CRT monitor weighs up to 40 lbs., give or take, while an LCD monitor can weigh as little as 15, give or take. This all depends on what type and how big the monitor is going to be of course. Also, LCD monitors are (just for example) about as thick as the front cover of a CRT monitor, saving space for all the clutter so many of us have. Some are made to be hung up on a wall and can obviously fit in spaces that CRT monitors will never hope to go. If the thought of placing a CRT monitor on a say, thin shelf, makes a person shudder, an LCD will take that worry away in most cases as the weight and thickness will not be a problem. Being a thinner monitor, LCD can also be set back further from the user as some would have to move further from the keyboard with CRT to get some eye relief as I do.
LCD has a backlight, which illuminates the desktop in almost any condition. Without the glass screen of a CRT, your glare and viewing improve. The backlight has a typical half brightness point of 50,000 hours and is typically the only component (made of fluorescent tubes) that ages. A CRT monitor, with the cathode ray tube, has typically 10 to 20,000. So, really what that says is (in theory) you will get 30 to 40,000 more half point brightness hours, before dimming occurs or display fails. That is a fairly large span in terms of numbers. LCD's also generate very little heat as opposed to CRT monitors, and this has much to do with less circuit breakdown and longer overall life of the monitor.
LCD seems to have many features and each company makes different features per monitor, and to try and name each is impossible. You can look at this link just for the purpose of giving you an idea of what some have/don't have, price etc...There are many links out there, many companies and as I always say, don't be afraid to ask when buying a product. If you are paying for it, you have a right to know anything you want to know about it.
Then of course there is Price...
Typically an LCD monitor is going to be more costly than a CRT monitor, but the prices are dropping and becoming quite comparable. So much that some don't consider the difference to be a problem when pricing. This price drop is good news for LCD buyers. Also, every brand is different, sales do matter, quality etc... There are so many shopping options these days, it's hard to pinpoint a price and doing a search is the best way to find what you want as I mentioned above.
In closing, what I would like to try and sum up is, CRT's advantages are becoming null and void as LCD is rapidly filling any gaps that CRT may have put between them. Some will say LCD already fills these disadvantages, while other sites and stores will say no. The confusion is there, but ultimately it is up to you and I hope that this will help you in some way.
Submitted by: Paul K. of Gladstone, Michigan