Return to the CurtPalme.com main site CurtPalme.com Home Theater Forum
A forum with a sense of fun and community for Home Theater enthusiasts!
Products for Sale ] [ FAQ: Hooking it all up ] [ CRT Primer/FAQ ] [ Best/Worst CRT Projectors List ] [ Setup Tips & Manuals ] [ Advanced Procedures ] [ Newsletters ]

 
Forum FAQForum FAQ   SearchSearch   MemberlistMemberlist  Photo AlbumsPhoto Albums  RegisterRegister 
 MembershipClub Membership   ProfileProfile   Private MessagesPrivate Messages   Log inLog in 
Blu-ray disc release list and must-have titles. Buy the latest and best Blu-ray titles to show off in your home theater!

Passive 3D on CRT... worth a project?

 
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> 3D Products
View previous topic :: View next topic  
Author Message
[Frankie]



Joined: 16 Jun 2014
Posts: 70
Location: Italia


PostLink    Posted: Tue Oct 10, 2017 12:56 pm    Post subject: Passive 3D on CRT... worth a project? Reply with quote


        Register to remove this ad. It's free!
Hi! I've got in mind this project these days. I saw on the internet that there are kits to transform a projector in a 3D Passive projector by means of one (or in this case 3) Liquid Crystal Shutter that goes up to 120Hz. I guess i could make it on my own a system like that, except for the fact that i can't find any Liquid Crystal Shutter. The only one i've found was on this site: http://www.liquidcrystaltechnologies.com/products/lcdshutters.htm . This company can produce Liquid crystal shutters at the size i need to. I still haven't asked the price but i guess it will be a bit expensive.

My idea was: I place three liquid crystal shutter plates in front of the tubes with polarized filters. Then i have bought a Kit from internet, the e-dimensional 3D wired kit with a dongle VGA that goes out with a 3,5mm Jack or a 3D Vesa Plug. I connect the three shutter plates with a circuit that pilots them (that i will build if it's not that hard) with the signal that goes out the 3D Vesa Plug. Then i send a HD Resolution (720p i suppose) at 96Hz or 120Hz to the projector. the Dongle between the projector and the HTPC will exit the sync signal to the controller of the shutter plates and then it should be over. The three shutter plates turns on and off at the sync signal. So there's passive 3D on the projector, is that correct?

Let me know if you have got some ideas or corrections! Thanks for any reply!
Back to top
[Frankie]



Joined: 16 Jun 2014
Posts: 70
Location: Italia


PostLink    Posted: Tue Oct 10, 2017 12:57 pm    Post subject: Reply with quote

The projector that i think i'll use is a NEC XG 135 LC.
Back to top
AnalogRocks
Forum Moderator


Joined: 08 Mar 2006
Posts: 24711
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Tue Oct 10, 2017 4:48 pm    Post subject: Reply with quote

With LCD shutters it would be called active 3D wouldn't it?
_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
kal
Forum Administrator


Joined: 06 Mar 2006
Posts: 14975
Location: Ottawa, Canada

TV/Projector: JVC DLA-RS56


PostLink    Posted: Tue Oct 10, 2017 5:02 pm    Post subject: Reply with quote

Correct.

Passive means you have two projectors, each with passive polarizing filters in different orientations to match passive polarizing filters that are in the glasses (one per eye). This means one eye sees one projector, and the other eye sees the other projector. There are no shutters.

Kal

_________________

Support our site by using our affiliate links. We thank you!
My basement/HT/bar/brewery build 2.0
Back to top
View user's photo album (18 photos)
cmjohnson



Joined: 03 Apr 2006
Posts: 5095
Location: Buried under G90s

TV/Projector: I'm building a projector fort!


PostLink    Posted: Tue Oct 10, 2017 5:05 pm    Post subject: Reply with quote

120 Hz refresh rate at full HD requires almost 300 MHz bandwidth, well out of the range for almost any projector.

Fast P43 phosphors would be required for ghostless operation.

The LCD shutters will cause significant loss of brightness, too, as even in the "open" position they're not exactly fully transparent.
Back to top
garyfritz



Joined: 08 Apr 2006
Posts: 10031
Location: Fort Collins, CO


PostLink    Posted: Tue Oct 10, 2017 5:12 pm    Post subject: Reply with quote

The ideal IMHO would be what Kal referred to as passive -- TWO projectors. Do a stack (both projectors aligned onto the same screen) with one showing left, one showing right. Then you just need passive polarizer screens in front of each lens and in your glasses. Each eye would see the full brightness of one projector, minus the loss of the polarizer. There wouldn't be any shutter flicker and you wouldn't need the 300 MHz bandwidth that CJ mentioned. But you would have to very carefully align the two projectors. Most stacks I know of used G90's, because of their geometry control and stability. You might be able to do it with a pair of XG's, but it would be a lot simpler to stack two G90's.
Back to top
[Frankie]



Joined: 16 Jun 2014
Posts: 70
Location: Italia


PostLink    Posted: Wed Oct 11, 2017 9:31 am    Post subject: Reply with quote

I understand. I didn't want to do stacking.. but effectively i could. I have got an XG 110, a XG 135LC and a 9PG Xtra. The Xg 110 needs service and the 135LC needs at least a new green tube. I've found three new tubes of a 135LC on eBay few days ago and i see these days to buy them. Is there some guide on the internet on how to do the stacking with CRT Projectors? Later i'll search a bit anyway. And for you can it be done for example with the XG 135LC and the NEC 9PG Xtra eventually?
Back to top
garyfritz



Joined: 08 Apr 2006
Posts: 10031
Location: Fort Collins, CO


PostLink    Posted: Wed Oct 11, 2017 1:15 pm    Post subject: Reply with quote

Yes I'm sure it could, but the geometry controls on the xg and pg mean they will be harder to align than a g90.

One thing I'm not sure about is how well the polarization stays aligned when it hits the screen. I assume it must work because it's been done, but it might require circular polarizes - not sure.
Back to top
barclay66



Joined: 27 Jun 2011
Posts: 1198
Location: Germany

TV/Projector: Marquee 9500 Ultra


PostLink    Posted: Thu Oct 12, 2017 9:47 am    Post subject: Reply with quote

Hi,

You might find this interesting:
http://www.projectorreviews.com/home-theater-and-projectors-the-technical-side/passive-3d-projection-part-1/

Regards,
barclay66
Back to top
View user's photo album (25 photos)
garyfritz



Joined: 08 Apr 2006
Posts: 10031
Location: Fort Collins, CO


PostLink    Posted: Thu Oct 12, 2017 1:10 pm    Post subject: Reply with quote

Ya, that's what I suspected -- you can lose polarization when the light hits the screen, unless you use a special (and no doubt $ex$pen$ive$) screen material. Which is high reflectivity and thus has hotspotting issues.
Back to top
barclay66



Joined: 27 Jun 2011
Posts: 1198
Location: Germany

TV/Projector: Marquee 9500 Ultra


PostLink    Posted: Thu Oct 12, 2017 4:36 pm    Post subject: Reply with quote

Hi,

There’s one exception to this rule: Dolby 3D (there’s a Wikipedia article explaining how it works)! It uses narrow-banded color filters.
Unfortunately, those filters -large enough for CRT lenses- are very expensive...

Regards,
barclay66
Back to top
View user's photo album (25 photos)
AnalogRocks
Forum Moderator


Joined: 08 Mar 2006
Posts: 24711
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Thu Oct 12, 2017 6:32 pm    Post subject: Reply with quote

Didn't Clarence have some poarizers with a batch of CRT stuff he got once?
_________________
Tech support for nothing

CRT.

HD done right!
Back to top
View user's photo album (27 photos)
Display posts from previous:   
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> 3D Products All times are GMT
Page 1 of 1
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum