Laser TV

[Kabuchan]

What's the difference?

[nwg]

It uses lasers instead of a electron beam.

Another site.

http://www.cdfreaks.com/news/14092

[Derree]

so...and I know this is not an easy question...what, right now, is better LCD or Plasma...I am looking to buy in Feb or march...and want at least 42" if not bigger...

[TNT]

In my opinion, LCD's major advantage is that it does not burn in. This is important because if you intend to watch 4:3 with black bars on the side as I intend to (as you should), you could develop bars on the side with a plasma. Plasma is definitely cheaper for a similar sized screen though.

[lfcrule1972]

I have to agree I think LCD edge out Plasma's on quality and also on length of service. My father in law did loads of research on the two types earlier this year.

He eventually went for a Panasonic Viera LCD and I have to admit the pic is awesome. The Gym I go to has 3x Plasmas on the wall that run from 7am to 22:30, in three years all three have been replaced for various technical faults and even now on the ones that remain you can see burn-in of news logo's and clocks when the channels are changed. That would annoy the hell out of me. I realise that these are extreme examples however but just the possibility of it happening to me would be a concern.

[nwg]

Plasmas produce a better picture but as already said there are problems. The burn in is a big one and can affect stations with onscreen logos in the corner. The logos burn in the screen and can be seen when another channel is chosen. I have seen this happen as quick as 30 minutes.

[toomanycats]

There are a lot of broken pasma's on sale on Ebay. The picture tubes aren't that long legged. LCD's last a long time. Just think of all those ancient laptops witht he display still working.

[nwg]

There are a lot of broken pasma's on sale on Ebay. The picture tubes aren't that long legged. LCD's last a long time. Just think of all those ancient laptops with the display still working.

I remember the silly urban legend that the gas in plasmas need replacing after a few years.

I have even seen ebay auctions for faulty plasmas and stating they don't work probably because the gas need replacing.

[RFBurns]

There are a lot of broken pasma's on sale on Ebay. The picture tubes aren't that long legged. LCD's last a long time. Just think of all those ancient laptops witht he display still working.

Good followup!!!

I was going to mention about the "ancient" laptops still showing pictures with their early version LCD pannels. Although they do not incorporate the "tiny mirror" chips (DLP), they are still working, dont know about the laptops themselves tho!

Difference between Plasma, LCD, Laser, CRT.

Quiet please...sit down and open your notebooks to page 3.

CRT--Cathode Ray Tube, is basically a small "particle accelerator". It uses thermal emission to "break away" electrons from a heated cathode plate that is attracted to the anode at the front of the tube (screen) when high voltage is applied. The accelerated electrons strike the surface of the front of the tube that is coated with reactive material known as "shadow mask". When the electrons hit the shadow mask, it "glows" producing light. The electron beam is moved from one edge of the tube to the other (left to right) to "scan" the surface, hence a picture is produced. The beam is magnetically influenced by a strong magnetic field that is generated around the neck of the CRT tube by a "yoke" that moves the beam both left to right and top to bottom. The yoke is given its drive pulses from the horizontal and vertical scan circuits. Other plates inside the CRT provide focusing of the beam, as well as intensity of the beam (brightness) and biasing voltages that also contribute to the accelerating of the electron particles. Black and white CRT's use one beam, while color CRT's use 3 beams (red/green/blue). When a CRT becomes weak, it is mostly due to the buildup of particles on the surface of the cathode emitter, blocking the free movement of electron particles, hence the tube gets "weak". Sometimes a CRT can be "bumped" or rejuvinated, a process that simply applies large amounts of voltage to "zap" away the buildup of particles and restores emission.

Plasma Flat Pannel--A flat glass, gas filled tube that follows similar principles as its old CRT grandfather. Instead of accelerating electron particles that strike a coated surface, the Plasma tube has millions of emitters placed side by side. When a voltage is applied to the emitters, it reacts with the plasma gas and produces light. The Plasma tube requires high voltage to "excite" the gas around the emitters. Because of the fact the tube uses a gas, it is not uncommon that a Plasma tube becomes weak after a short period of time, usually within 4 years depending on usage and elevation. The gas becomes inactive and the tube becomes useless and must be replaced. A Plasma tube cannot be rejuvinated or "recharged".

LCD--Liquid Crystal Display. As the name implies, a LCD pannel uses tiny liquid crystal elements placed side by side. However there is no gas, and no high voltage to excite the elements. The nature of a liquid crystal element produces light by simply applying a small voltage to its PN junctions. Very similar in function to a light emitting diode (LED). The LCD element also has a bias lead, this allows the control of the voltage applied to the PN junctions like a transistor. The more bias voltage applied, the more conduction in the PN junction, which results in less light or more light produced. Newer LCD elements incorporate very tiny mirrors around the LCD element just like a flashlight reflector. This is what makes the newer LCD units produce pictures that can be viewed at any angle without degridation to the picture, which is what the major drawback was in the older LCD displays. The mirrors are constructed inside the LCD element, commonly refered to as "DLP chips".

Laser Display--Laser TV. An array of laser emitting elements using red, green and blue lasers that are combined at their focal point onto a screen surface. Just like the LCD pannel and Plasma pannel, millions of tiny laser emitters are placed side by side to produce the overall picture and screen size. However the laser display uses no gas, no high voltage and no backlight. It does use tiny lenses to focus the 3 beams into one combined beam before it hits the screen surface. Without today's ability to miniturize the laser emitters, a laser tv would end up being 4 times the size of a regular CRT screen of same viewable size. Today's elements that make up the emitters are capable of the high switching rates required for clean, lag free motion. Without high switching ability, meaning able to turn off and on very quickly, a laser tv would be impossible. The lasers must be able to turn off instantly and completely, and turn back on again at the same fast rate or there would be considerable picture delay in even moderate scene motion. Until very recently, the materials used to make laser emitters was not good enough for high switching rates while maintaining intensity.

The Future:

This is a little inside information. Currently there is heavy research and development being done on pure crystal displays. These neat little puppies are not in any way like the LCD, it is a pure solid crystal excited by a very tiny voltage to produce light. The crystal has conductive elements that react at certian switching frequencies, causing resonance within the crystal that makes it produce the light. Depending on the resonant frequency applied, the crystal produces light across the visible light spectrum as well as emissions outside the visible range, which is the problem. Another setback is the fact that the elements within the crystal does not live very long. The research continues for development of more reliable crystals that will hold up and last longer than a few minutes!

[toomanycats]

Do direct view LCD panels incorporate the mirror set up (DLP). Why is a color wheel required on the DLP projector/rear projector as opposed to direct view? Do DLP's produce better blacks than direct view LCD panels? I think SONY should have you write a primer to give people at the locals SEARS stores to educate the sales people and customers. You make it seem easy.

[nwg]

what do you mean by direct view?

All the DLP setups I have seen have better blacks and colours than my LCD projector. However, it is several years now and the latest LCD PJ's are probably similar now in colour. The LCD TV I had similar colours than the DLP projector I have seen but not as sharp and looked a bit too smooth. The DLP PJ had more detail.

The latest really expensive PJ's uses 3 separate chips each for Red, Green and Blue instead of colour wheels and are the same as digital cinemas/theatres.

More recent and expensive LCD PJ's use separate LCD panels instead of one panel (like my PJ) for RGB. They use mirrors to direct the light through the LCD panels.

http://www.agocg.ac.uk/brief/lcd.htm

This is a mind blowing demo about DLP (millions of mirrors that move in different directions!!!)

http://www.dlp.com/dlp_cinema/includes/demo_flash.asp

[TNT]

nwg, good find on DLP!

[toomanycats]

I was referring to the direct view LCD panels as opposed to the DLP rear projection TV's. I was wondering if the direct view TV incorporated the mirror technology and if that was why the view angle has increased. I personally would never buy any TV/Projector that has moving parts. My Sanyo projector uses 3 LCD panels and it's 4 years old. After viewing that clip on DLP I am more of the opinion that LCD is the way to go. Too many moving parts. Color wheel technology is old, very old. I don't think they will have the long legs of LCD TV's/Projectors. I could be wrong but I am sticking to Direct view LCD panels and LCD projectors.

[nwg]

Afaik, each mirror in a dlp represent a pixel. So, if a mirror did happen to go, it would affect that one pixel.

I am now not sure if I have one panel or three thinking about it. It is a Panasonic PT-AE100.

I am sticking with LCD for the foreseeable future. The new Panasonic AX100 is simply awesome but it costs £1000.

This is DLP of House of Flying Daggers.

http://img246.imageshack.us/img246/7031/dagdlptu6.jpg

This is my AE100 LCD PJ. The colours do look a lot better in real life as it was taken with a low res camera. It still shows the difference). A new LCD PJ should be much better.

http://img301.imageshack.us/img301/2848/daglcdtl7.jpg

[toomanycats]

I always use red as a reference point when I set the color. If the reds bleed past the border then the color is set too high. I like the pic off of your Panasonic better than the DLP as the colours seem more tru to life. When I look at TV's I always play with the color and bright/contrast settings to see what the TV really has. I start with color all the way down to see how the grey image loks like. That is the best way to see if the Temperature is too high, and then do the rest of the setings. The guys at my local SEARS used to hate me but now actually have asked to to adjust some of their TV's. My local Sears carries a lot of TV's.