Posts Tagged ‘LCD’

LCD Monitor – Are they the same?

In Electronic on 18 March, 2006 at 6:25 am

They seem the same, so are they the same?

Response time?  Sure some are 4ms, some 8ms and some 12ms.  But in actual fact these figures might not be measuring the same thing.  Response time refers to the speed of pixels, how fast can they change from color to color.  A faster response time will not cause a “ghost” effect to appear in games and movies.  However, nowadays, the panels are fast enough that you will hardly get any that will be that bad.  Furthermore, the response time measured might be from gray to gray or black to white, depending on which is the fastest.  Thus, on average most panels are really responding at the same speed.

Contrast?  Brightness?  For contrast, a 500:1 is normally good enough, which is the standard nowadays anyway.  Brightness is actually quite adequate for any LCD panel, normally it is above 250 cd/m2.

So are there really any difference?  Luckily, there are, if not they won’t be price so differently.  I think the current most important difference is the color depth.

Color depth refers to the number of colors the panel can produce.  Currently there are 6 bit and 8 bit panels.  8 bits panel are the so called true color panel as it can display a total of 16.7 million colors.  This is the best panel if you are interested in watching movies on your monitor, or even for future gaming that is of a high definition.  6 bit panel can only display a total of 0.262 million colors.  This is actually the same color depth as the latest mobile phone display.  However, monitor manufacturer use a technique call dithering to help to increase the color depth in 6 bit panel.  This technique display two close colors very fast so that only one is seen and thus fool the eyes into thinking that it can see more colors.  With dithering the perceive color depth becomes 16.2 million colors.

A panel that can produce a total of 16.7 million colors is still the best for watching movies and graphic designing.


HD Ready?

In Electronic on 23 February, 2006 at 5:00 am

I don’t think so.  After so many years of bombardment by marketing terms, “XXXXX Ready” should alert you that something fishy is going on.  Recently, I went around looking at the HDTV products that are currently available on the market.  I have also blog about some Plasma Vs LCD.  TV manufacturers are using the “Ready” trick again, specifically “HD Ready”.

They are not wrong when they said that certain technology are “Ready” in their products, but to us consumers, we need to know what do they mean by “Ready”.  “Ready” does not necessary means that the product already has that technology.  It can means that you need to add certain component to get that technology, or that it can simply interface with that technology.  In this case “HD Ready” really just means that the TV can accept any HD input.

So what is HD input?  Let’s start with SD.  SD is Standard Definition and is the current format of normal TV.  It means that the video display has roughly about 480 viewable lines.  HD on the other hand is High Definition and consist of at least 720 viewable lines.

Coming back to “HD Ready”.  Certain cheaper TV Panel although it claims “HD Ready”, you can’t really enjoy HD quality when the format becomes vastly available.  This is because this type of panel can only display 852 x 480 pixels.  Which means that at most it can display 480 lines horizontally.  Which means that this panel is actually a SD panel.  So although it can accept HD input, it will use some technique to decrease the 720 or more lines to only 480 lines.  This is of course not true HD quality.

Some people will say, “Well, I can’t see the difference.”  This is true, unless the shop you go to has HD broadcast set top, you can’t really see the difference between SD and HD.  DVD is actually a SD input source and normal broadcast is also of a SD quality.  So when both SD and HD panels are displaying SD video, how can you see the difference?

So the next time when you go shopping for a new TV and want it to be able to last another 5-10 years, you need to check the specification and see what resolution does the panel support.  If it states that the panel can support 1366 x 768 or 1024 x 768, then you can rest assured that this panel can display HD quality video.

Plasma vs LCD – again

In Electronic on 9 February, 2006 at 6:08 am

Which is good?

Plasma will give a better black, since it can off its pixel totally which will make it as black.   LCD on the other hand use filter to change color and thus will only give shades of gray and not true black.  However, with today’s technology, LCD’s “black” is not as obvious to the naked eyes.

LCD will give a sharper image.  Thus when you walk into a room with both plasma and LCD of the same size, you will first be attracted to the LCD panel as it look nicer.  But after staying in the room for sometime, you will feel that the plasma panel is nicer to watch.

Plasma has a burn-in effect, meaning if you watch a channel with a channel logo on the top right corner and watch only that channel.  After sometimes the color at that top right corner will be similar to the logo even when you watch other channel without any logo.  There will be a dim logo as if it has been printed on the screen.  But this is very rare.  LCD doesn’t suffer from this effect.

Plasma has a life span of 30,000 hours, but if you do the maths, watching TV 10 hours a day, 7 days a week, your plasma will still last you 8 years.  And if you drop it down to 5 hours a day, which is more of a norm, then it will last you 16 years.  LCD on the other hand doesn’t neccessary has a standard life span, but the light bulb will burn out after sometimes and it can be changed.  But the cost of changing the light bulb is normally quite expensive.

Plasma is cheaper now as compared with the price of an LCD of the same size.  This is because plasma as a technology is more mature than LCD, at least in terms of bigger screen TV panel.

Both are good technology, so in the end it is just your budget and your eyes that will decide which panel you will ultimately go for.  Just remember don’t let the sales person decide for you, you are the one using it and not him/her.

Plasma vs LCD – which is better for our eyesight

In Electronic on 8 February, 2006 at 5:02 am

During one of my Chinese New Year gathering, one of my friends asked me whether plasma or LCD is better for one’s eyesight.  My answer was that both are OK.  Since plasma and LCD are both fixed pixel display (meaning to say both don’t draw pixel one by one from left to right, all pixels are drawn at the same time), flickering is a non-issue.  Both panels also do not emit low-radiation and thus not harmful to our health.  Which lead me to conclude that both panels are better for the eyesight than conventional TV and both are equally good.  Provided that brightness and contrast are set to a comfortable level.

However, after giving the issue another thought, I feel that the time you spent in front of the TV is still important.  The focusing of our eyes at a certain object for too long, will make our eyes too dry and will cause myopia.  Thus after watching TV for 2 or 3 hours, one should take a break and let our eyes have a good rest, like looking out through the window at some beautiful scenery.  This way, we can maintain our eyesight and still enjoy our favourite TV programme.