New design glass and mirror ???

[my1423]

Im building my first projector and i want to make a new style.
Its going to stand straight up like a water cooler and use a mirror to reflect to the screen. The basic projector will be very similar to the lumen labs simple 15 inch, but will be verticle and not horrizontal. but differant than the mk 111 due to the mirror outside the case on top past the triplet.
This way it will take up little floor space and blend in with my other speakers and entertainment center of the 3 1/2 foot tall range. Also the output will be close to the center of my screen in hight so little keystone adjustment will be needed. I have very low cellings and celling fans so ceiling mounts are out. This will allow me to lengthen the case in order to add more internal goodies with ease in order to get the height i want. I want it to look like one of my old large stereo speakers. I might even add a grill and sub.
I have a few planning issues before i get started.

1. Can a mirror be used after the triplit lens and still keep a good picture quality or do i need to put it in the case before hand like the mk 111? I was going to mount it on top outside and able to flip up for use like the old transparrency machines.
2. Do I have to use a front side mirror to reflect after the triplet or can a regular mirror be used? How bad is the regular?
3. Any recomendations on where to buy a fs mirror?
4. Since im having a longer case can the insulating glass be mounted at a 45 degree angle to the lamp instead of 90? This for heat reduction or will it cause some sort of distortion? I want to angle it to get better heated air movement out of the case to prevent hot spots and allow the unit to self cool if i loose power or have some malfunction. Heat of course rises so if i put the inlet at the bottom and the outlet in the to 45 corner it should creat its own draft.
5. When you go to a glass store what do i ask for in order to get uv and or ir blocking glass? Bulk regular stock items? item #s Energy glass ect? The local glass store didnt know what i was talking about and told me that I would have to buy a 4 x 8 sheet if special order. They only know tempered, auto, and energy ratings.
6. Anyone try mobile home window crank drives for focusing the lens and keystone correction? Im going to try unless anyone has any beter ideas.
7. Any ideas for better lens slides? Im thinking of using cut down ball bearing drawer slides to mount the lens on and the window mechs to precisely move them easily.
Sorry about all the ?? on first post but have been reading tons over the last 2 weeks and these are some ??? I have for the most part not seen answers to.

Thanks

[my1423]

Forgot one other ?
Im planning on using a regular mogul base and the smaller of the 2 large bulbs just like the lumen lab projector uses. I already bought the bulb but like everyone im having a hard time finding the right reflector. I found another really cool looking bulb on ebay and bought it. Here is the link.
http://cgi.ebay.com/ws/eBayISAPI.dll...e=STRK:MEWA:IT
I could not find any specs on it but maybe someone else has seen this. Might be a good future bulb choice, or if not speak up. Once i get it i can post the actual philips part number if its good to use for others.

Also had another idea. Breaking off the outer casing, and using one of the small reflectors for the hqi bulbs sold here. I know that it will emit large amounts of uv but im going to insulate it with uv glass. You also have to solder over the little air protection circut that turns off the bulb when exposed to the atmosphere. regular projectors use exposed elements so i dont see why this wont work to make a cheaper bulb. Please post your thoughts, so i can save 20$ on a bigger bulb to use as a test subject.

[mkl2]

To answer some of you questions:
1. No problem, most of the OHP’s are designed like that.
2. Use a front surface mirror; with a regular one you’ll get a doubled projection.
3. LL or DIYPC
4. I don’t think will hurt, a steeper angle might decrease the light output.
5. Yes, tempered glass can be used as a IR filter, but you’re better of with some heat reducing glass.
6. I don’t think they are accurate enough.
7. This is my idea for a focusing mechanism.

Breaking off the outer casing...

Actually, this idea haunts me for quite some time, but I never got the time to put it into practice. This was successfully tried here with an Osram hqi-t 150W, but I never seen it done with a 400W MH.
This is what it should look like; magenta is the machined aluminum casing, red is the reflector and green is the condenser lens.
I really wont to know if this is doable.

[dnsey]

I've also wondered about removing the outer envelope, but I'd be careful.
Apart from the UV issue, the envelope acts as protection if the capsule explodes, which it can do violently, so be sure never to operate the lamp without some sort of guard in place.
It also protects the capsule from overcooling, which can reduce efficiency and also lead to stress and consequent explosion.
You'd have exposed lead-in wires carrying high voltages (up to 5kV or so during ignition) so you'd have to take care with access and airgaps (don't forget that that UV can cause ionisation, making the surrounding air conductive - your own little lightning storm ).
I'm not saying don't do it - just that, as so often, there's more to it than meets the eye.

[mkl2]

The lamp will explode towards the end of its life. But, compare to the 1mm glass envelope, I’m prepared for that with 5mm aluminum and 20mm thick tempered glass (Borosilicate to be precise). I’m not over-engineering things here, the casing I think it should be that to give it some thermal stability and the lens is that thick because of its focal length and diameter. Actually, if it would be made from Pyrex it would be thicker.
Obviously the lens should be UV treated.
Now the part what I don’ know; the chamber should be pressurized or not? In any case there should be little to no airflow inside it. Thermal exchange is done through radiation also, but is that such a big issue here?
Clearly at least of one wire will be insulated with a ceramic tube. This is not clearly mark in my drawing, but if it weren’t, the ionization would be the least of my problems.

[my1423]

I like your pvc focusing slide. That is nearly identical to how crt big screens are focused and i had condisidered it with wood but not with pvc. That is a much easier way than i was thinking of and i think im going to do something very similar. Thanks

The window cranks were more of an idea to use on the fresnel for keystoning and was trying to brainstorm of a beter way for the triplet. I was going to use 2 window cranks one for each axis and put my fresnel in 2 frames with center pins so they can be moved on both axis points.
Any better ideas for the keystoning and do you really need both axis for adjustment or just 1? One would really simplify things!

I have been greatly debating the whole bulb issue and i think im going to give the element only routine a shot even though i have already purchased 2 bulbs. I am thinking of using an old kc daylighter for a sealed incloser with lens and reflector to mount my 400 watt bulb envelope. They are designed to put out a perfect even beam so i think its a good start. Its also almost 8 inches in diameter so it should have no real space issues! Im not going to mount it horizontal but vertical like the original bulb it used. This should hopefully keep the beam even. All of the internal bits are metal and glass so it should take the heat. My buddy runs a electronics repair shop and he has showed me many bulbs for dlp and lcd tvs and they all use a bear element cemented into and encloser. Most are even plastic! Not sure how they dont melt but they do contain the exploding core very well when they burst. I think they use the plastic for this very reason for hot tempered glass breaks sooo easily when disturbed. None of these are compleatly sealed. They all have small holes for the expanding air.

WARNING do not touch the bear element! The oil in your hands will cause the bulb to break!

[mkl2]

Keystoning, ain't gonne get more simple than that.



Based on what you described and what I’ve Google-it, KC’s are parabolic reflectors. And they won’t work. At least not with a condenser fresnel, and certainly not with a 15” lcd. This is because a parabolic reflector outputs a parallel beam. This rules out the condenser, but unless you find a 15” diameter daylighter, you’ll have to settle with an 8” lcd.
Yes, with both elliptic and parabolic reflectors, vertical is the correct burning position.
First is a elliptic and second is a parabolic reflector.

[my1423]

K.i.s.s. is the best policy for everything.
What did you use for the adjuster? Just a spring washer with a knob? Pefect simplicity! I was going to use much larger mecanism with either a piece of 1/4 inch allthread and a knob or window cranks but that looks nice. you can go full circle and return to the original spot without hitting your lcd. Did you do both axis?

As for the daylighter not working I understand what your saying, but i have an out with that. Since i am making mine verticle i am making a very large case! 36-40 inches high. I have enough room to move the light back far enough for the focal piont of the kc to match the focal point of my fresnell. Imagine your diagram just as it is but the convergance points match at the focal point. This is the same as a piont sorce or the regular no reflected design for the fresnel still does the work of evening out the light. The kc just sends back a large amount of the recycled light at heier set focal lenghts. At least i think this will work pretty good. If you have ever got to use one the beam is beautiful! completely even.

I have to go to work. Talk in 36hrs.

[ramkishan]

We started with an OHP and then modified to long throw lens to position the projector at ceiling height. The details are available at the following link to our web page:-
http://www.drtsolutions.com/Projector.com

[my1423]

I know that you built a pretty nice projector and your proud of it. You should be,

BUT

You starting to drive me ******** crazzy!

You highjack everyones thread and post a link to your site about your projector witch does not give all that much of a detailed discription but lots of pictures of it in action.

Enough is enough!

Most forums would have banned you already!

Please stop!