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DLP RPTV *VERTICAL* Viewing angle

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4 replies to this topic

#1 of 5 OFFLINE   Sanaka



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Posted April 24 2003 - 12:25 AM


The viewing situation I'm addressing is that the viewers sprawl on the floor with the TV about 5' up. The only wide screen technology I'm aware of that will deal with this kind of vertically off axis angle is plasma. All RP sets I've seen do the disappearing picture act at about 20 degrees off vertical. Becasue plasma is too expensive in an adequate size, our most recent upgrade was to the 40" Sony Wega. It's a real honey, but still we yearn for bigger and wide.

So now I'm intrigued with DLP RP. Specifically the Samsung 50" or 61" (HLM507W / HLM617W). Everything I've read (nowhere to demo it in Kona) sounds like this is really sea-change technology. Can anyone tell me whether it has also finally solved the RP vertical angle problem?

On a more generic note, it seems to me that this off axis problem is more an issue with the projection screen surface/transmission, or possibly the lens system, than whatever technology is producing the light. Anyone know what's up with that?

Thanks, it's good to be back Posted Image


#2 of 5 OFFLINE   Steve Schaffer

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Posted April 24 2003 - 12:01 PM

You are correct in your assumption that off angle rptv light loss has nothing to do with crt vs dlp, only with screen technology. Sony's KPxxWV700 models supposedly have some new technology to improve the situation, but I haven't checked it out for myself.
Steve S.
I prefer not to push the subwoofers until they're properly run in.

#3 of 5 OFFLINE   Allan Jayne

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Posted April 25 2003 - 04:54 AM

In order to have more RPTV picture brightness at greater vertial angles, we either need the CRT's (or projection lamp) to deliver more light overall (closer to the danger point of CRT phosphor burn for a larger viewing screen), or have a dimmer picture overall from any angle.

The current RPTV technology, notably the lenticular screen layer, provides better light distribution to the sides when the viewer's eyes are approximately level with the screen, and less light higher and lower.

By replacing the lenticular layer with a plain frosted panel you will improve the vertical angle visibility, and make the overall picture dimmer although more even from all angles.

If you had a lenticular screen layer with the ribs going across, the vertical angle if favored. You will have plenty of screen brightness for people seated, standing, and sprawled, but not off to the sides.

If when someone is seated, everyone is seated and if someone is sprawled, everyone is sprawled, you can rig up some arrangement to tilt the top of the TV forward, but you must be absolutely sure the TV cannot tip.

Video hints:

#4 of 5 OFFLINE   Sanaka



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Posted April 25 2003 - 07:54 AM

Thanks Allan and Steve Posted Image

Steve the Sony WV700 'uniform screen brightness' is exactly what I've been waiting for in terms of viewing angle. 60 degree vertical works! BUT... DLP is exactly what I've been waiting for in terms of everything else (especially convergence and burn in).

Allan thanks for confirming my surmise that the critical light distribution happens at the screen. We considered a tilted TV, but decided enough tilt would look really funny and might not solve the problem adequately. I read that DLP is supposed to be very bright. If it is in fact brighter than CRT, and since it has no burn in problems, it seems a prime candidate for an adequately bright, 'uniform brightness' implementation like Sony has done with CRT.

Any definitive confirmation whether or not Samsung has in fact done this with their DLP units?

If so, I may several K poorer real soon Posted Image Thanks!


#5 of 5 OFFLINE   sean_pecor


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Posted April 25 2003 - 02:24 PM

Have you considered a front projection / direct view combination?

If you had a $4,000 budget, here is one setup:

Toshiba 36" 36HFX7 16:9 Direct View ($1,500) for day to day watching (if you've got kids etc).

Panasonic PT-L300U ($1,900) for movie nights / sports events.

DaLite Model C 92" 16:9 Matte White Screen, Manual Pull Down ($325).

This sort of arrangement offers the fewest compromises for severe angle viewing. Watch the "small" TV for regular content, watch the "big screen" for movies. Your projector lamp will give you around 2,000 hours (1,000 movies and events) and a new lamp will be around $300.

Just a thought.

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Digital Spinner, Inc.

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