Put a HQI-bulb in a commercialprojector

[mathias]

I have now finished my diy-projector, consisting of a 15" TFT and a 150W cdm-t bulb, and a new light engine that use most of the lumens the bulb produce (more info about how the lightengine works you can find in the thread "videoprojector part II" page 116), I´m satisfied with the picture quality and the brightness. But the diy projector is too big and beautiful isn´t it. It looks like a nuclear-missile, And if I mount it in the roof I will get pretty flat if it falls down

So I have thought of an other idea: Buy a cheap commercialprojector, people are selling them cheap sometimes because they can´t afford to buy a new bulb. Replace the expensive UHP-bulb (Ulta High Preformance) with a cheaper HQI-T 150W bulb, of course I have to use an external ballast. My question is what ANSI-lumen can I expect if I do that ?
Let say the commercialprojector use a 150W UHP-bulb and give 1000 ANSI-lumen with that.
Is the UHP-bulb so much more effective than a HQI-bulb ?
Will it be brighter than my diy-projector ?

[golftdibrad]

I think the trick will be to
1.trick the projector into thinking the bulb is fine
2.Focusing the parabolic reflector from the old bulb with you new, cheaper replacment. Kinda like your picture. this would give you about the same ansi lumens (assuming the bulb your using has the same lumen output as what its replacing)
3.Fit you cheaper and probally larger bulb into the space intended for that tiny blub.
If you could overcome these problems this would be a very cost-effictive way to go with a DIY projector, and alot nicer too. Plus the pj would be BEHIND the seating area.

Let me know if you try this, i'd be very interested in the results!

[msx-2]

i tried to do this with my proxima dp2800. However space is very limited and the light path is far from perfect(dp2800 uses about 4 first surface mirrors ,and the beast is a hell of a difficult machine to get apart (never seen a electronic device so difficult to dissasemble). Maybe in the future i take the thing apart and put it into a new housing. However, i think my lcd-controller is a little screwed up . There is some kind of raster over the projected image (its not the fresnell) .It's very strange and i don't know what it is.

[Hezz]

I wouldn't be surprised if some of that OEM bulbs specialness is marketing hype. The only issues I can see that you need to deal with are element alignment and UV and IR issues. For instance the OEM bulb may have IR glass around it to reduce the heat output.

Hezz

[mathias]

If I can in some how put the HQI-bulb in right place and focus it, and I mayby need to put the bulb a little outside the commercialcase in a extra box, but does anyone know if I can turn of the message "Please change the bulb" that I have seen in some shop ?

Which projector will be brightest and the best choich ?

1. Diy 7" TFT lilliput, with a 150W HQI, 200:1 contrast, 800*480 res.

2. Cheap commercialprojector 3 panels TFT 400:1 contrast, 800*600 res, change bulb to a 150W HQI.

I have seen some old projectors on the market that use one 6" TFT panel and a 250W HID, and this this thing only put out 250 ANSI lumens, wouldn´t the 7" TFT lilliput thing get less bright ?

[mathias]

I finally bought a cheap commercialprojector, I couldn´t resist, the price was only what you pay for two 15" tft monitors. Well the UHP-lamp will last in 1500h and a the price for a new one is the same as for a new 15" tft. So of course I will not buy a new lamp-unit.
I found out that a UHP-bulb is actully the same as a HID short arc lamp, so the only diffrents between a HQI and a UHP is that the arc is smaller in the UHP, the light output is the same.

The UHP-lamp unit puts out a parallel beam that is 50mm wide. I think it´s not so difficult to build a HQI-light unit that puts out a parallel beam of that size. And because the light is parallel we can use a mirror so we can place the light-unit outside the pj-case.

[mathias]

UHP-unit front picture.

[mathias]

I asked before which of the two choiches below that are the most worth to buy.

1. Diy 7" TFT lilliput, with a 150W-250W HQI, 200:1 contrast, 800*480 res.

2. Cheap used commercialprojector 3 panels TFT 400:1 contrast, 800*600 res, change bulb to a 150W HQI.

I did a very intressting comparision between the two choiches.

The pictures to the right are the diy-projector and to the left the commercialprojector. The pictures up is with the lights on, and down it´s off. The diy-projector, consisting of a 15" TFT and a 150W cdm-t bulb, and the new light engine with a PAR30-reflector. Because I use the PAR30 reflector it will be equal to a 7" -design.

The pictures are taken with the same camra, same dvd-player, same surrounding light and same screen-size 100". My camra don´t like dark pictures, so what seems dark is not so dark. Which would you choose ?

[mathias]

This is a another screenshot of the diy-projector, bright isn,´t it ?

Well, now the screen size is only 60", so it´s very easy to get foold.

[mathias]

I´M SORRY I WROTE WRONG !
THE DIY-PROJECTOR IS TO THE LEFT AND THE COMMERCIAL TO THE RIGHT !