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Discussion Starter #1
I was looking over an old brochure for the NEC XG 135LC and had questions on two things. The original document can be found here ->
http://www.cinenow.com/us/downloads.php3/mk,25/

Click on the download button under brochures, XG85 & XG135lc (Video Projector)


In it, the brochure states:


Liquid Coupled Optical System

The liquid coupled lens system on

the MultiSync XG135LC projector

replaces the air space between

the CRT and the lens elements with

a liquid, reducing the amount

of light lost through secondary

reflection. This results in a 40%

increase in contrast and a 20%

increase in brightness.



My understanding is that the LC option would increase contrast, but lower brightness. Granted, this is a brochure, so this is probably marketing rather than technical specs... Or would increasing the contrast allow one to crank the brightness up e.g. run the tubes harder? Seems to go against what I've read otherwise.



Also, they mention improving 3D image by adding a short persistence green tube. Maybe Curt has seen one of these... Would this work for HT? Are the tubes you (Curt) put in already short persistence,? Are they even available?


MultiSync XG Series projectors can be

optimized for 3D image projection with the

addition of a short persistence green phosphor

tube. “Persistence†refers to the length of time

the CRT phosphor glows after the electron

beam has stopped projecting electrons onto

its surface. Phosphors with longer persistence

have a higher light output. However, long

persistence also can cause a “ghosting†effect,

which occurs when the phosphor continues

to glow from the previous image while a new

image is projected. Because 3D imaging

systems have a very fast refresh frequency,

they require projectors with short-persistence

phosphors in the CRT. Adding the short-persistence

phosphor option to the CRT

of MultiSync XG Series projectors, ensures

optimum performance with 3D imaging systems.

This tube is available as an upgrade for

your MultiSync XG Series projector or can be

purchased with the tube already installed

(model numbers XG85S, XG135S).



Curious to find out.. thanks!


Marshall
 

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As you can read by yourself, only the XGs with the suffix S have the short persistance tube built in.

Roland
 

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Discussion Starter #3
Yes, not really my question though... As stated above, it also could be purchased separately to upgrade an XG.


Anyone tried this in HT? How does it work?
 

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If you would try this in HT you will get lower light output and more flicker if you would not go to higher refresh rates (96 Hz or higher).

Roland
 

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In the XG75 specs the LCs are rated 240 ANSI Lumens vs. 230 for the non-LC ones.


Maybe you have a little more transmission-loss by the liquid, but much less loss due to reflections..

Roland
 

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They are referring to the use of a short persistence P43 phosphor tube instead of a regular P22 phosphor tube. This is ONLY necessary when using 2 projectors for "real" 3D, not the "3D look" that some forum members allude to.


As for the "increased brightness", this is as a result of loosing less light from beam scatter. Optically speaking, the less stray beam scatter, the higher the light transmission ratio. Whether that is actually true in practice, remains to be seen, however, an LC coupled lens certainly results in a much sharper higher contrast picture.


Bruce
 
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