Are CRT rear projection TV's obsolete?

[0roo0roo]

Cathode Ray Tube (CRT) Direct View and Rear Projection TVs

Technology Overview & Description
A cathode ray tube (CRT) is a specialized vacuum tube in which images are produced when a moving electron beam strikes a phosphorescent surface. There are three factors that limit the resolution on CRT display devices: screen dot pitch, electron beam size, and the bandwidth of the video amplifier. A typical CRT has a dot pitch around 0.8 - 0.9mm (much larger than a typical computer display). Lowering the dot pitch increases the display resolution, but increased dot pitch provides a brighter picture. Most CRT displays are configured to perform well with lots of ambient light, so dot pitch is typically higher.

Dot Pitch Explained: Dot Pitch, or phosphor pitch, is a measurement indicating the diagonal distance between like-colored phosphor dots on a display screen. Measured in millimeters, the dot pitch is one of the principal characteristics that determines the quality of display monitors. The lower the number, the crisper the image. The dot pitch of color monitors for personal computers ranges from about 0.15 mm to 0.30 mm.

Rear projection TVs typically utilize 7" CRT guns, with some of the higher-end models using 9" guns (like the Mitsubishi WS-65813). 7" guns can typically resolve about 700-800 lines of resolution. The high end 9" guns can do upwards of 900 lines. Typical direct view televisions deliver just over 600 lines of resolution. Most RPTVs have at least 30Mhz of video amplifier bandwidth, which is good for just under 720p or 1080i. Better models have upwards of 75Mhz. Most direct view televisions have 20Mhz video amplifiers, with some higher-end units extending above 30MHz.

CRT televisions receive video signals at the rate of 30 frames a second. Each frame of video contains about 480 lines of information. A single frame is projected on the screen line-by-line in two passes (each pass is called a "field"). On the first pass, the beam projects all of the odd numbered lines from 1-479 from top to bottom. On the second pass, it projects all of the even numbered lines from 2-480. It takes 1/30 of a second to complete both passes. This process is called interlacing. CRT type TVs need time to reset the electronic beam to the top of the screen so it can get ready to paint the next sequence of lines. To accomplish, they build in an interframe gap that equals about 45 lines. There is no picture information here. So the total lines per frame are 525 (480 + 45). Thus standard definition TV (SDTV) is often referred to as 480i (interlaced).

What?s Next
Extinction. Front projection CRT-based systems are all but gone already. Rear projection CRT is soon to follow as soon as LCOS and DLP systems drop in price. As rival flat screen and digital projection technologies drop in price and increase in quality, there will become less and less reason to pay for the bulk and power consumption of CRT displays.

CRT Direct View/Rear Projection Advantages CRT Direct View/Rear Projection Disadvantages

* Among the brightest and clearest alternatives
* Excellent color and contrast potential
* Relatively inexpensive
* Excellent life expectancy



* Heavy
* Very deep
* Analogue connectivity or D/A conversion of digital input connections
* Potential for screen burn-in

http://www.audioholics.com/techtips/spe...ts/displays_cathode_ray_tube_CRT7.html

 

[Amused]

Originally posted by: PurdueRy

Originally posted by: spidey07
I was referring to rear projection, but could be applied to front projection.

I was under the impression that direct view suffer from limited resolution when trying to display HD due to the raster. I've seen it when I put HD resolution test patterns on them.

He asked whether you were talking about direct view or RP. Not FP.

As I said before I believe CRT RP is obsolete. But obvious Direct view CRT is still the best in terms of PQ, just not in terms of practicality.

Again, as I said previously, you're wrong.

Put a DLP and a properly, professionally calibrated CRT RP in the same darkened room (theater environment) and watch a movie with lots of dark scenes in it. The DLP will look positively gray compared to the deep, rich blacks on the CRT.

As I said, for the average family room, a DLP is good. But for a theater environment (my preference) CRT RP, FP and DV is still king.

 

[0roo0roo]

As I said before I believe CRT RP is obsolete. But obvious Direct view CRT is still the best in terms of PQ, just not in terms of practicality.

yea but it doesn't scale. the only good direct view crt is the sony fine pitch crt, the others are a joke in terms of actual resolvable resolution. the fine pitch doesn't really hit the full resolution of hdtv either though. it maxes out at 30ish inches, and thats becoming inadequate compared to the competition

 

[Kremlar]

Almost. While CRT holds benefits over newer technologies (DLP, LCD, plasma, etc...), it also has many shortcomings, such as:

- geometry
- viewing angle
- size/weight
- light output
- drifting
- burn-in

While some people will hold onto CRT, the vast majority of people will be spending their money elsewhere, and the number of products using CRT will continue to dwindle.

 

[0roo0roo]

yup, flat panels get ever better, no company is probably spending any r&d on crt.. its just gonna die

 

[Amused]

Originally posted by: Kremlar
Almost. While CRT holds benefits over newer technologies (DLP, LCD, plasma, etc...), it also has many shortcomings, such as:

- geometry
- viewing angle
- size/weight
- light output
- drifting
- burn-in

While some people will hold onto CRT, the vast majority of people will be spending their money elsewhere, and the number of products using CRT will continue to dwindle.

Which is sad, because in a theater environment, no other technology can hold a candle to CRT.

BTW, calibration and a darkened room negate almost all of your negatives. And proper theater seating removes the viewing angle whining.

 

[Don Vito Corleone]

Originally posted by: BurnItDwn

Why Holy Moly?
Are you saying that's too far???
I know that 6.3 feet is the optimal viewing distance (36% FOV for full immersion), however, being at a slightly lowwer resolution, I find between 7 and 8 feet to be the perfect distance. It's quite immersive, and everything is very sharp from that distance.

I prefer to keep my distance to the TV within the recommended THX Viewing angle.
When I go to a movie theatre, I like to sit in the middle.
With my home setup, it's just like as if I was sitting in the middle of a movie theatre.
http://www.myhometheater.homestead.com/viewingdistancecalculator.html

No, I'm saying I would regard that as way too close. I have a 50" set I watch at 8-9 feet away, and I can't imagine watching a 61" from that distance.

 

[Excelsior]

Originally posted by: Svnla

Originally posted by: Whoozyerdaddy
.......LPs beat CDs hands down for sound quality. Better freq response, real sound vs sampled sound...

LP is better than CD in sound quality? I remember LP made all the pop and crackle noise when I played them years ago.

I am waiting for the slim fit CRT HD Widescreen comes down to about $500 for 30" unit. The Plasma/LCD/etc are too expensive for my taste right now <$1K or more for a good midsize set>.

The pop and crackle you hear is not because of the LPs sound quality, but because the album is likely not clean, and the needle may need to be replaced.

IMO, CDs beat LPs in one factor that matters the most to consumers. Convenience.

 

[Excelsior]

Originally posted by: Kremlar
Almost. While CRT holds benefits over newer technologies (DLP, LCD, plasma, etc...), it also has many shortcomings, such as:

- geometry
- viewing angle
- size/weight
- light output
- drifting
- burn-in

While some people will hold onto CRT, the vast majority of people will be spending their money elsewhere, and the number of products using CRT will continue to dwindle.

Ill give you the geometry and size/weight agument...but viewing angle? No. Light output? No. Burn-in? Hell no. That hasn't been a problem for a LONG time.

 

[Kremlar]

Which is sad, because in a theater environment, no other technology can hold a candle to CRT. BTW, calibration and a darkened room negate almost all of your negatives. And proper theater seating removes the viewing angle whining.

Since you're saying "in a theater environment", I'm assuming you're talking front projector.

I've lived both lives, and have to say I'm happier with my DLP.

I had an expenseive CRT front projector a while ago, and I fought with it's large size/heavy weight, the drifting, the relatively low light output, the geometry, etc.

Now that I've gone DLP, I do miss the better black levels, but I love the extra light output, love not having to worry about the geometry or drifting (which means I rarely re-calibrate). And man, mounting it to the ceiling was a breeze. I'm also able to project onto a huge screen.

 

[Kremlar]

Ill give you the geometry and size/weight agument...but viewing angle? No. Light output? No. Burn-in? Hell no. That hasn't been a problem for a LONG time.

Uhh... yeah. Wrong.

The viewing angle is far better on, for example, a typical plasma than a typical RP CRT.

Light output, while not really an issue on a RP CRT, is a huge issue on a front projector. Try finding a not astronomically priced CRT FP that can project with enough light output onto a 65"x116" screen.


And burn-in certainly is an issue for any CRT. I'm not saying everyone with a CRT will get burn-in, but a less than ideally adjusted set or someone who watches TV for long periods of time with a static images (say a specific station logo, or 4:3 bars on the side, or a video game) may certainly experience burn-in. Same with plasma. But they won't get it on an LCD or DLP.

 

[Amused]

Originally posted by: Kremlar

Which is sad, because in a theater environment, no other technology can hold a candle to CRT. BTW, calibration and a darkened room negate almost all of your negatives. And proper theater seating removes the viewing angle whining.

Since you're saying "in a theater environment", I'm assuming you're talking front projector.

I've lived both lives, and have to say I'm happier with my DLP.

I had an expenseive CRT front projector a while ago, and I fought with it's large size/heavy weight, the drifting, the relatively low light output, the geometry, etc.

Now that I've gone DLP, I do miss the better black levels, but I love the extra light output, love not having to worry about the geometry or drifting (which means I rarely re-calibrate). And man, mounting it to the ceiling was a breeze. I'm also able to project onto a huge screen.

Front or rear.

And to me, the FAR better black levels outweigh any other negative you can give.

Nothing kills the suspension of disbelief for me more than gray blacks (other than bad acting, directing, or writing, of course).

 

[Kremlar]

And to me, the FAR better black levels outweigh any other negative you can give.

Take a look at a good DLP if you haven't - you might be surprised. It's certainly not as good as a good CRT, but the shadow detail is heads above LCD.

Nothing kills the suspension of disbelief for me more than gray blacks (other than bad acting, directing, or writing, of course).

Nothing enforces suspension of disblief for me better than a nice huge screen that only a digital projector can provide (for a reasonable price).

 

[PurdueRy]

Originally posted by: Amused

Originally posted by: PurdueRy

Originally posted by: spidey07
I was referring to rear projection, but could be applied to front projection.

I was under the impression that direct view suffer from limited resolution when trying to display HD due to the raster. I've seen it when I put HD resolution test patterns on them.

He asked whether you were talking about direct view or RP. Not FP.

As I said before I believe CRT RP is obsolete. But obvious Direct view CRT is still the best in terms of PQ, just not in terms of practicality.

Again, as I said previously, you're wrong.

Put a DLP and a properly, professionally calibrated CRT RP in the same darkened room (theater environment) and watch a movie with lots of dark scenes in it. The DLP will look positively gray compared to the deep, rich blacks on the CRT.

As I said, for the average family room, a DLP is good. But for a theater environment (my preference) CRT RP, FP and DV is still king.

That may be your opinion. But
#1 I have seen both and I believe the advantages of DLP make up for its shortcomings.

#2. Not many people want to calibrate their TV professionally every few months just to keep their picture looking nice.

#3. DLP is generally brighter and has a slightly wider viewing angle

#4. DLP has virtually perfect geometry and little overscan

#5. DLP has smaller depth and comes in tabletop format

#6. DLP can now do 1080p also

There may be points which it doesn't do as well in such as black levels. But, having hassled with a RP CRT calibration system for quite a while I prefer the ease of DLP rather than the frustration of CRT RP

That does not constitute me as "wrong"

 

[Kremlar]

The bottom line is that if CRT were a new technology introduced today, no one would stand for it's shortcomings. Same with LP vs CD. Same with LD vs DVD when DVD was first introducted - you had nutballs complaining about digital compression artifacts, when they'd been living with analog artifacts for decades! They were just used to the analog artifacts! They weren't looking at DVD vs LD with an unbiased eye.

A buddy of mine is a moderator at AVS Forum and was a CRT nut for years. He had a very expensive Electrohome CRT projector - one of the best ones out there. He went DLP about a year ago and hasn't looked back since.

The answer to the OP is: "yes - if they are not considered 'obsolete' today, they will be very very shortly'.

Take a look at any decent home theater shop - what percentage of what you see is CRT?

 

[91TTZ]

Originally posted by: Amused
CRTs still offer the best black levels for low light theater style viewing.

I've yet to find a DLP, LCD or plasma that looks as good as my professionally calibrated CRT RP in a dark room.

Granted, for high light TV viewing, DLPs are better. But if you're into movies in a darkened room, CRTs will walk circles around a DLP.

This is why the best high end FP units are still CRT.

2nd that.

I bought a CRT HDTV around Christmas. I specifically wanted a CRT because I read that they have better pictures than LCD or projection TVs.

It looks fantastic.

 

[Excelsior]

Originally posted by: Kremlar

Ill give you the geometry and size/weight agument...but viewing angle? No. Light output? No. Burn-in? Hell no. That hasn't been a problem for a LONG time.

Uhh... yeah. Wrong.

The viewing angle is far better on, for example, a typical plasma than a typical RP CRT.

Light output, while not really an issue on a RP CRT, is a huge issue on a front projector. Try finding a not astronomically priced CRT FP that can project with enough light output onto a 65"x116" screen.


And burn-in certainly is an issue for any CRT. I'm not saying everyone with a CRT will get burn-in, but a less than ideally adjusted set or someone who watches TV for long periods of time with a static images (say a specific station logo, or 4:3 bars on the side, or a video game) may certainly experience burn-in. Same with plasma. But they won't get it on an LCD or DLP.

You mean someone who leaves it on one channel (that never changes its image) for 12 hours a day, every day, for a week? Ok.

Now who does that? I have yet to hear of anyone in the past 5 years have an issue with burn in.

 

[Kremlar]

You mean someone who leaves it on one channel (that never changes its image) for 12 hours a day, every day, for a week? Ok.

No, I mean someone who brings a set home and doesn't calibrate it properly, and maybe watches a lot of CNN, or someone who has a kid that leaves his Xbox paused with the TV on all night (this happens more than you might think).

I have yet to hear of anyone in the past 5 years have an issue with burn in.

Then educate yourself.

http://www.avsforum.com/avs-vb/showthread.php?t=406182


I'm not saying a high percentage of CRT users get burn-in - on the contrary, I think it's extremely rare. However, it is a potential issue to consider, depending on your use, since ZERO percent of DLP/LCD users experience burn-in.

 

[tfinch2]

:hugs 27" CRT HDTV;

 

[0roo0roo]

Originally posted by: tfinch2
:hugs 27" CRT HDTV;

"hdtv"
at that size the crt definetly isn't really capable of putting out the full detail, the dot pitch is just too coarse.