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Anyone into LED modding their old LCDs?

 
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winny



Joined: 09 Oct 2013
Posts: 401
Location: Sweden

TV/Projector: BD808s, BG1209/2


PostLink    Posted: Sun Apr 24, 2016 6:53 pm    Post subject: Anyone into LED modding their old LCDs? Reply with quote


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My old Sanyo died some time ago and I wanted to see for myself if it could be fooled but although it was a simple open collector output from the ballast when the bulb was up an running, the MCU did not accept it being always high at bootup. Threw it in the garbage.

Got myself a free Panasonic 800x484 LCD projector which wound's start. Turns out the Philips class D TDA-driver for the speaker had developed a short and fried the power supply. When I bypassed the power supply and injected all voltages manually, it smoked good! Lifted Vcc of it and tied the ballast output to ground and voilá - picture!

Next step, replace the flashlight with something brighter and more convenient while keeping costs to a minimum - Chinese 100 W LED. Way way too large to be able to focus good into the 50x50 mm light opening of the projector but good enough for a test.



DAMN IT BECAME INEFFICIENT!

Original LED had 45 Cd/W measured with lens and 26 without it. Didn't dig too deep into the beam angle and integration but 70 lumen/W seems reasonable.

With lens, I got 12.3 lux at an 19x33 cm large "screen". Working out to 0.75 lumen while pushing in 14.8 W. That's about 20 W/lumen or a whopping total of 5 lumen if I push the full 100 W into it.
Tried removing the lens but no laptop to test with since the ground return becomes the VGA-connector so I can't use my PC with this setup but it was very similar.

Has anyone else experimented with this? I'm thinking about changing the LED setup to a fiber optic colimating lens to match the beam characteristic of the original bulb better, but that will limit the maximum power of the LEDs involved a lot.



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Last edited by winny on Fri Mar 02, 2018 5:30 pm; edited 1 time in total
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cmjohnson



Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s


PostLink    Posted: Sun Apr 24, 2016 7:07 pm    Post subject: Reply with quote

Two words: "Luminus Phlatlight".

Now you understand why projector optics are designed by trained engineers. It can be surprisingly difficult to illuminate the engine
optics uniformly and brightly.

But this is a project that interests me. I think there may even be a viable market for LED replacements for high power arc lamps for the larger, more expensive commercial projectors.

I once got two Barco SLM R6 3 chip DLP projectors for 500 dollars. One was complete and working, the other was missing a lens and had a speckled blue DMD. I sold the lens for 500 dollars and the lamp housings with lamps brought me a thousand bucks!


Those lamp housing assemblies (with lamps) are seven thousand dollars each from Barco.


Yes, there's a buck to be made here.

Somebody needs to make it.
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winny



Joined: 09 Oct 2013
Posts: 401
Location: Sweden

TV/Projector: BD808s, BG1209/2


PostLink    Posted: Sun Apr 24, 2016 8:12 pm    Post subject: Reply with quote

Original plan was LEDengin LZP which had 5700 lumen in 8x8 mm package IIRC, and machine an 30 mm TIR lens to accept the 10.6 mm dome on the LED. Very few drivers would fit inside the casing and this guy actually costs money. 5700 lumen is on pair with the original bulb but as far as beam angle goes, this guy coupled with seven rebel LEDs will give 2100 lumen but similar beam angle: http://www.luxeonstar.com/polymer-7-led-cluster-concentrator-optic
I'll add the drawings tomorrow when I'm not drunk.

If I had the time and money, an 3 chip DLP and separate R, G and B LEDs would be the end-game for me. Can you fake the bulb OK on your R6?

Edit: Oh, and I am a trained engineer. Just don't want to spend too much time and money into a sub-720-projector.

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Digital is easy. This is torture, but far more interesting...
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cmjohnson



Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s


PostLink    Posted: Sun Apr 24, 2016 8:55 pm    Post subject: Reply with quote

I don't have the R6 units anymore. They got scrapped for a substantial profit. But the working one was very nice.


I believe that those units just needed to see light at the lamp sensor. Disabling the HV strike pulse and tapping the control signal for the lamp strike circuit to switch on the lamp drive (maybe with a triac to make it a one component mod) might have been all that it would have needed.

The lamp housing was adequately roomy for most anything.
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AnalogRocks
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Joined: 08 Mar 2006
Posts: 25636
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Tue Apr 26, 2016 1:37 am    Post subject: Reply with quote

I'd love to see an LED bulb for the JVC DILA G series 10,11,15 etc.... those bulbs retail for $850 Rolling Eyes
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winny



Joined: 09 Oct 2013
Posts: 401
Location: Sweden

TV/Projector: BD808s, BG1209/2


PostLink    Posted: Tue Apr 26, 2016 8:41 am    Post subject: Reply with quote

Electrically it would be very challanging but not impossible to do a drop in replacement and interface against the high voltage igniter and run of the original ballast but the biggest challange would be heat since your arc lamp will radiate away 99 % of the heat and heat up all surrondings and especialy hit any dichotic mirror and the stock cooling is designed for this whereas your LED will conduct 99 % of the heat and need to be cooled locally. The bare bulb vs. LED efficiecy is similar. Perhaps a factor of two for the most efficienct LED (120 lumen/W) vs. some very inefficienct UHP (60 lumen/W), but that 1% vs. 99 % is what kills off that equation.

If the projector is roomy enough to fit a large heatsink, then it would work. On my small LCD I did the calculation and it is not possible without a hurricane blowing though the lamp area.


Here is my lens suggestion for the LZP. The green hashed area needs to be lathed away. The TIR part will not function here but having the LED seated inside the lens is of far greater importance.



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Digital is easy. This is torture, but far more interesting...
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AnalogRocks
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Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Wed Apr 27, 2016 12:19 am    Post subject: Reply with quote

The JVC G series uses a huge heatsink on the bulb


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winny



Joined: 09 Oct 2013
Posts: 401
Location: Sweden

TV/Projector: BD808s, BG1209/2


PostLink    Posted: Wed Apr 27, 2016 7:48 am    Post subject: Reply with quote

Interesting!

Is it very high power? That low % conduction will become significant once the power is high enough. Water jacketed (correct term?) xenon-lamps in multi-kW-range exists for a reason, even though they too radiate away the very vast majority.

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Melifluonze wrote:
Digital is easy. This is torture, but far more interesting...
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AnalogRocks
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Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Wed Apr 27, 2016 11:46 am    Post subject: Reply with quote

winny wrote:
Interesting!

Is it very high power? That low % conduction will become significant once the power is high enough. Water jacketed (correct term?) xenon-lamps in multi-kW-range exists for a reason, even though they too radiate away the very vast majority.


That does look like a set of water connections but in fact those two pipes are the electrical plugs to power the bulb.

These projectors use between a 420 watt to 500 watt bulb depending on model. At Halloween we just turn the heat off in the house and let the projectors heat the place. We heat our hands on the exhaust air from the projectors we use out side.

I'll see if I can find a better picture of the bulb.

For the JVC DILA G20U. Bulb # BHL-5003 SU



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Jeremy112



Joined: 28 Sep 2006
Posts: 2643
Location: Fond du Lac, WI


PostLink    Posted: Wed Apr 27, 2016 2:05 pm    Post subject: Reply with quote

AnalogRocks wrote:
winny wrote:
Interesting!

Is it very high power? That low % conduction will become significant once the power is high enough. Water jacketed (correct term?) xenon-lamps in multi-kW-range exists for a reason, even though they too radiate away the very vast majority.


That does look like a set of water connections but in fact those two pipes are the electrical plugs to power the bulb.

These projectors use between a 420 watt to 500 watt bulb depending on model. At Halloween we just turn the heat off in the house and let the projectors heat the place. We heat our hands on the exhaust air from the projectors we use out side.

I'll see if I can find a better picture of the bulb.

For the JVC DILA G20U. Bulb # BHL-5003 SU


I have an empty JVC housing like this (Also used in another brand that I cant remember atm), it would be perfect for a high lumen LED mod for those who are inclined to do so, the huge heatsink would likely keep any LED cool (especially if it can keep those Xenons running!)

This is an interesting thread to watch you guys work on. I have to admit the screenshot of the projected image with the LED mod in the OP actually has (what looks like on this POS LCD monitor anyway) good color! Thats a good start. And it appeared to have an evenly lit image, just not very bright.

You can pick up 5k lumen to 10k lumen LEDs on superbrightleds.com (and other places online of course), they are fairly big LEDs, but I believe they would be ideal for illuminating a PJ. They would require the use of a heatsink obviously as well.

On a good note, at least most digital PJs should be ready for LED/mods as far as cooling goes, thats one thing they already have worked out Very Happy

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gjaky



Joined: 05 Jun 2010
Posts: 2688
Location: Budapest, Hungary


PostLink    Posted: Wed Apr 27, 2016 3:38 pm    Post subject: Reply with quote

Normal white LEDs are made out of blue leds with special phosphors on them (that shifts wavelength more or less). For projection you'd need RGB LEDs, because phosphor based LEDs have poor to zero emittance in red. You can reach nice D65 (white) point from virtually infinite combinations, for projection however the peaks of red-green-blue primaries are pretty much settled, and strict. If you want faithfull color reproduction that is the minimum to match all the intensities and peaks of the original lamp's spectra. Cheap chinese LEDs often lack a datasheet that is true, and without it you are just taping blindly.
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AnalogRocks
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PostLink    Posted: Wed Apr 27, 2016 9:36 pm    Post subject: Reply with quote

gjaky wrote:
Normal white LEDs are made out of blue leds with special phosphors on them (that shifts wavelength more or less). For projection you'd need RGB LEDs, because phosphor based LEDs have poor to zero emittance in red. You can reach nice D65 (white) point from virtually infinite combinations, for projection however the peaks of red-green-blue primaries are pretty much settled, and strict. If you want faithfull color reproduction that is the minimum to match all the intensities and peaks of the original lamp's spectra. Cheap chinese LEDs often lack a datasheet that is true, and without it you are just taping blindly.


The issue with driving a DILA like that is the light engine is sealed. The RGB panels form 3 sides with the lens on the 4th. The white light comes in and gets split.

I wonder how driving a DILA with a laser and a phosphor would work? Like the SONY VPL-FHZ55 1920x1200 projector. It's rated 4000 lumes. These JVC's are rated 1000-1500.

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cmjohnson



Joined: 03 Apr 2006
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Location: Buried under G90s


PostLink    Posted: Thu Apr 28, 2016 11:20 pm    Post subject: Reply with quote

Here's my quick and dirty suggestion: Get the optical core out of a cheap scrapped LCD display and using clear epoxy, such as 3M's DP100 Plus Clear, directly glue a red, green, and blue Luminus Phlatlight LED to the (former) RGB LCD faces of that optical core.

Of course you would carefully remove the RGB panels from that optical core before applying the Phlatlight LEDs.


You will now be able to use the RGB Phlatlight LEDs in the LCD core operating in reverse, thus delivering well aimed combined RGB light into the subject projector's optical engine.

All you have to do next is balance the aggregate RGB outputs for white light and you've managed that bit of mischief.
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cmjohnson



Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s


PostLink    Posted: Sat Apr 30, 2016 10:17 pm    Post subject: Reply with quote

AnalogRocks, the type of lamp you are showing is made by Osram or Perkin-Elmer and they're actually made in only a very
limited number of power levels. I have seen various versions on ebay on a regular basis and they tend to go pretty cheap because most people don't know what they're looking at.

This may give you an opportunity to score a compatible lamp for a considerably reduced cost.

BTW, the front glass is a pure man-made sapphire window. Pretty cool stuff, and if you can salvage the window it's a nice
little conversation piece.

These lamps are under a LOT of xenon gas pressure, so when you break the seal with a drill, file, or grinder, expect a loud hiss.
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AnalogRocks
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Joined: 08 Mar 2006
Posts: 25636
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Sat Apr 30, 2016 10:20 pm    Post subject: Reply with quote

cmjohnson wrote:
AnalogRocks, the type of lamp you are showing is made by Osram or Perkin-Elmer and they're actually made in only a very
limited number of power levels. I have seen various versions on ebay on a regular basis and they tend to go pretty cheap because most people don't know what they're looking at.

This may give you an opportunity to score a compatible lamp for a considerably reduced cost.

BTW, the front glass is a pure man-made sapphire window. Pretty cool stuff, and if you can salvage the window it's a nice
little conversation piece.

These lamps are under a LOT of xenon gas pressure, so when you break the seal with a drill, file, or grinder, expect a loud hiss.


I had a DILA G20U from eBay with a bad power supply. It killed the bulb. When it blew up it sounds like a gun shot.

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AnalogRocks
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PostLink    Posted: Wed Nov 08, 2017 9:42 pm    Post subject: Reply with quote

And developments on the LED substitues?

I've got an LCOS Canon projector here that's seriously hurtin' be perfect for this.

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