Inside a TFT Monitor

Keith Williams writes "Ever wondered what's inside your TFT monitor? Bit-Tech took one apart and stripped it down to the panel to find out. There's also some great explanation of the technology that goes into your desktop display."

Comments

Bugs

[Anonymous Coward]

""Ever wondered what's inside your TFT monitor?"

Exploding Caps.

One benefit of CRT

[Bralkein]

One day I was using my computer, when I noticed something strange on the screen. It was a little grey mark, moving about on the screen in a seemingly random fashion. It was a little bug of some kind... but it was actually under the screen! I tried to shoo it out of the monitor, but I accidentally squashed it to death, because I forgot the screen of a TFT is flexible. Now there is a little stain on everything I view, thanks to the tiny insect corpse. This would never have happened if I had bought a CRT instead!

Re:One benefit of CRT

[the_humeister]

That's not a bug, it's a feature!

Re:One benefit of CRT

[c0l0]

Quick! Someone inform PETA that advanced display technology poses death threats to our sweet, little and innoncent insectoid friends! This kind of development has to be stopped most immediately!

Re:One benefit of CRT

[rebeka thomas]

I wouldn't say that anything to do with a CRT is a benefit. They're blurry, hot, electricity-hungry and contain a large dangerous vacuum on your desk in front of your eyes, while sitting you right in the direction of an electron gun while firing x-rays out the back.

No thanks. Good riddance to bad rubbish.

Re:One benefit of CRT

[Anonymous Coward]

Nice troll. Why would you think the radiation from a CRT is that different from the radiation from an LCD when they look very much alike? Well, they look alike except for the fact that LCD's are still horrible jokes compared to a quality CRT, but both output light.

Re:One benefit of CRT

[kerrle]

I hate to even respond to this, but actually the radiation output of LCDs and CRTs is considerably different, due to how they generate the picture.

Also, if you think LCDs are still horrible jokes, you haven't been shopping lately. I'm a late convert as well, but the quality on even mid-range LCDs to day is way better than it was even two years ago.

Re:One benefit of CRT

[jcgf]

Well CRTs are cheaper for one. Secondly, I still think the picture on a typical CRT looks better than an LCD which costs twice as much. Now this may change when you go to the really expensive models but then your spending more money.

Re:One benefit of CRT

[Digital Pizza]

If the CRT's front surface were to break (you'd have to hit it pretty hard with a hammer or something), exposing the "dangerous vacuum", it would implode, not explode; the glass would get sucked inside. The vacuum is probably the least dangerous thing about a CRT.

Re:One benefit of CRT

[tsa]

My six-year-old Iiyama 19" CRT at home performs a lot better than my 3-year-old Iiyama 17" LCD at work. And I'm also not so sure about LCDs being less power-hungry. A friend of mine has a 19" Philips LCD that uses 125 W; just as much as my 19" Iiyama CRT.

Re:One benefit of CRT

[Alien Being]

That's not a feature, it's a creature.

Re:One benefit of CRT

[Bloater]

The glass will experience an inward force *where it breaks*, but an outward force everywhere else as air rushes in and the tensions from the pressure differencial during the inrush "flick" the rest of the screen outward. Normally when you break glass, it shatters and falls down. A CRT is one of the few exceptions where it will fly in your face of its own accord.

Re:One benefit of CRT

[evilviper]

I'm a late convert as well, but the quality on even mid-range LCDs to day is way better than it was even two years ago.

LCDs continue to improve, of course... And in 50 years, they might rival CRTs.

Show me an LCD that can really do 60+ FPS without any blur at all... Show me an LCD with even a fraction the contrast ratio the cheapest CRT can deliver. Show me some LCDs which can display real black, not just grey. Show me an LCD where you don't have picture distortion due to the location of the light... Show me an LCD where I can turn down the back-light enough that I don't get a tan, and can still read the screen without straining.

I'd like to have a display, that does't use as much power, but I'd bet advances in effeciency will make CRTs lower power than LCDs before LCDs can catch-up to the picture quality of CRTs.

I'm much more optimistic about DLP and future display technologies.

Re:One benefit of CRT

[evilviper]

And I'm also not so sure about LCDs being less power-hungry.

Yes, LCDs generally use about 50% as much power as CRTs, though that doesn't make-up for their other serious draw-backs.

A friend of mine has a 19" Philips LCD that uses 125 W; just as much as my 19" Iiyama CRT.

Those numbers are absolutely insane. You aren't going off the rating on the device are you? My Cheapo 19" CRT only uses 65W. (Also: a 19" LCD is 1" larger than a 19" CRT)

Re:One benefit of CRT

[evilviper]

Normally when you break glass, it shatters and falls down. A CRT is one of the few exceptions where it will fly in your face of its own accord.

Nonsense.

Modern CRTs include a bonded, multi-layer faceplate that prevents implosion, and also protects you from one as well.

Besides, you need a very, very specific (and very unlikely) combination of conditions for it to violently implode. Most of the time, the force of the rushing air won't even break the glass.

Re:One benefit of CRT

[The Wicked Priest]

Show me a CRT that can display a straight line. Or a pixel -- an actual pixel, instead of a blob.

All display technologies have their trade-offs. As for the LCD I'm looking at right now (a Samsung SyncMaster 172N), I've never seen the slightest motion blur on it, and any theoretical deficit it may have in contrast ratio is more than made up for by its nigh-infinite sharpness. I don't miss my CRTs, and I wouldn't go back.

Re:One benefit of CRT

[tsa]

Actually those 125 W are what is printed on the little stickers on the devices. I haven't measured the real consumptions, but usually these little stickers are pretty accurate.

Re:One benefit of CRT

[evilviper]

I've never seen the slightest motion blur on it,

The fact that your eyes aren't very good (or that you're so accustomed to it that you can't see it anymore), doesn't change facts.

Grab a good-quality interlaced DVD, and play it back with a field-seperating filter to get the full 60fps. The problem should become quite obvious then.

and any theoretical deficit it may have in contrast ratio

It's not theoretical at all. It really, really looks like crap, and is much harder on your eyes.

is more than made up for by its nigh-infinite sharpness.

It's really not sharper, it's just that there's a black-wire grid around every LCD pixel, which makes them easier to discern from each other.

You should know there are adjustments which will allow you to make any CRT PAINFULLY high-contrast if you choose to do so.

Re:One benefit of CRT

[evilviper]

Actually those 125 W are what is printed on the little stickers on the devices. I haven't measured the real consumptions, but usually these little stickers are pretty accurate.

My ~65W CRT has a sticker on the back that says 2AMPS!

In my experience, those stickers haven't been remotely accurate. Perhaps that's absolute peak-voltage at power-up...

Re:One benefit of CRT

[Anonymous Coward]

Find me a CRT that is flat, displays at least 1280x1024, that does weigh 20+ pounds, and can fit on any desk without requiring a lot of wasted room behind it.

Re:One benefit of CRT

[evilviper]

Find me a CRT that is flat, displays at least 1280x1024, that does weigh 20+ pounds,

Easily done (I presume you mean DOESN'T weigh 20+ pounds, but either way...).

and can fit on any desk without requiring a lot of wasted room behind it.

Yes, the added size of CRTs is a (very minor) draw-back. I'd say a standard keyboard and mouse waste much more desktop space than an average-sized CRT. I've always found it quite easy to work a CRT painlessly into any areas. Put it in a corner, at an angle, above the workspace (on a stand) etc.

As much as people tout the benefits of LCDs being flat, I don't see all that many running out to spend 3Xs as much money on a plasma/LCD/DLP TV.

Re:One benefit of CRT

[Anonymous Coward]

One of the irritating things about /. is the speculative babble.

I've worked in TV, monitor, and general repair work for over 30 years. I've smashed countless CRT's, and seen the result of many implosions.

Glass shatters into billions of tiny, incredibly sharp shards. But you knew that, right?

During a violent implosion, some of the glass pulls inward, but some splinters outward. Some bounces back out of the implosion. Bottom line- try it- you'll see (rather than imagine) that it can be quite violent and glass goes everywhere- fast- very dangerous to the eyes! (not to mention the toxins...)

Yes, the face of all CRT's is quite thick, and a sandwich of 2 glass layers with a very pliable rubbery plastic in the middle, exactly like automobile windshields.

There is a scenario, which I've seen happen, where the electron gun (the skinny part in the very back of the CRT) breaks off, getting sucked in, and crashes into the front face. It won't go through, but sometimes the impact causes some splintering of the face glass. It's pretty impossible to happen by itself (without direct human causality) especially because the attached magnetic deflection yoke's mass prevents the assembly from gaining much kinetic energy (speed.)

LCD privacy!

[ShaniaTwain]

If you peel the polarizing filter out of a LCD display and make sunglasses out of it, you'll have a display that no one can see without wearing the 'magic glasses'.

Re:LCD privacy!

[4D6963]

Very true. I remember doing the same with my calculator in 9th grade. Nobody could see what I was doing with it without looking throught he filter.

Imagine the potential of your idea tho. Would have loved to have this back when the only computer around was in a public room (kinda sucks to turn the screen off every time someone comes in and your watchin porn, I'm not even talking about trying to justify it)

Re:LCD privacy!

[biocute]

If you are watching porn, you will have to conceal more than just the screen if you don't want people to know.

Re:LCD privacy!

[darkmeridian]

There was a luggable PC with this "feature" way back in the 1990s: an LCD screen readable only with a special pair of glasses. Problem was, you had to sit exactly right to see anything. This was a tough proposition if you were using it in the cramped spaces the privacy feature would be most useful in: the subway, airplane, airport, etc. And you couldn't turn it off when you got home, either. Ech.

Oooh looky there ....

[taniwha]

an 'analog hole' .... quick call the MPAA

But...

[Sensible Clod]

if you tilt your head AT ALL, the picture goes wacked.

Re:But...

[Anonymous Coward]

actually it'll be a smooth transition from full bright at the correct orientation to full dark at the orthogonal orientation

Remember just because the world is made of quanta doesn't mean it acts like it - in this case the strongly elliptically polarized photons can pass through a partially oriented filter - think of them as having a quantum probability of making it through, based on the uncertainty principle and the difference in polarization...

20th Century called, they want their article back

[metamatic]

Coming soon in your up-to-the-minute Slashdot:

- What's inside a floppy disk drive?

- How magnetic core works

- What's inside that 8 track player in your car?

- Inside your Iomega Bernoulli Box

Well, yes...

[Sensible Clod]

of course. A lot of people know that. Is the adjective 'wacked' inapplicable? No.

One benefit of CRT-Bullseye.

[Anonymous Coward]

"They're blurry, hot, electricity-hungry and contain a large dangerous vacuum on your desk in front of your eyes, while sitting you right in the direction of an electron gun while firing x-rays out the back."

1. 
   "Blurry"

   
   Most CRT's have circuitry that adjust for the aging process.
   
   "Hot"

   
   Most devices that generate work, generate heat. Including LCDs. Anyway I'm in front of a CRT and it doesn't generate as much heat as you think.
   
   "electricity-hungry"

   
   Not as much as you think when in a non-sleep mode. And even less sleeping.
   
   "large dangerous vacuum on your desk in front of your eyes"

   
   I can tell that you've never looked inside a modern CRT. One that vacuum is in a special glass envelope. Two most have a metal shield backing.
   
   "while sitting you right in the direction of an electron gun while firing x-rays out the back."

   
   Special glass, and metal shield. Plus soft X-rays aren't going to be coming out the back. (hint: look up how X-rays are generated). And last you get greater amounts of ionized radiaton from other sources.
   

"No thanks. Good riddance to bad rubbish."

I could take some pot-shots at LCDs.

Re:20th Century called, they want their article ba

[Doubting Maxwell]

You know, this gives me an idea. We could make a site, that has a bunch of "articles" that explain how various common things work.
We could call it howstuffworks.c.... oh, wait. Nevermind.