My new projector plans...!!!

[mccamp82]

After building my 15" projector, i have decided to begin a new one. First of all, my liquid video is messed up. It has quite a few rows of dead pixels that cannot be fixed. This is very annoying when trying to watch a movie or use the computer. The X and the Resize buttons at the top right of a Window are absent due to dead pixels. SUCKS. Anyway, i am going to keep all of my parts, but use them for a lilliput projector. I am using all my optics from Lumenlab. I am going to switch to a ushio bulb. This projector will be a little bigger than bfourcades and ace's projectors, but will still me small and low profile. I am also looking forward to the longer throw distance and the wide screen. Here is an autocad drawing of my first design. I will probably make a few changes, but this one is still pretty cool. Tell me what you think.
Take care

 

[mccamp82]

Had to make a change. Got the length of the bulb wrong. Here are the altered plans. I like it better this way anyway.

 

[go77306]

You are talking about the 1005 kit at http://lumenlab.com/store/index.php ?
the focus lengths are too long, how can you fit it a box?

 

[mccamp82]

Why do you say the focus lengths are too long? There is no such thins as too long as long as the fresnels and objective lens work together. Size of LCD doesnt make a difference. You just cut the fresnels down to size. The focal length does not change.

 

[DEDan]

Sounds like a good plan, I like the idea of using the sandard lens set. I may make my next one using a small LCD so I can place the projector beind my couch instead of on the floor.

 

[bfourcade]

HI mccamp82 !

If you will use a 400w bulb without a cold mirror or a IR filter in the light path I encourage you to review your design to let run a fan over the LCD panel. It is the most important piece to cool down (then the light engine offcourse)
If your lamp hasn´t UV Stop , adding an UV filter will help to protect the LCD.

Bernardo.

 

[gstuder]

Hi mccamp82. Could you put the measures to your plan? thanks

 

[mccamp82]

bfourcade, thanks for the reply. Where can i get an IR filter? I will probably just change it to have a fna on the LCD. That should be simple enough. But an IR filter would be a good addition too. What is a good price for an IR filter, where do you get them, and can they be cut?
Thanks.

I will add measurments later today after work.

Take care

 

[mccamp82]

here is the new plan with dimensions (in inches). i have altered the plan a bit to get better cooling to the lcd and added av glass in front of the lcd to protect the lcd.

 

[mccamp82]

made a mistake on the drawing. messed up on the arrows for the airflow. the fan nearest the lamp is the blowing out. the one by the mirror is blowing air in. ill fix it later.

 

[mccamp82]

newest design. Added a mirror before the LCD. Whaddaya think?

 

[slizm]

NICE DESIGN!!!!!!!!!!!!!! It makes me want to start my lilliput project over again from scratch. Looks like things should run real cool inside Pj with your design.

 

[mccamp82]

thanks a lot slizm.
I just got my lilliput today. Can't wait to get started.

 

[Gigem]

DLP Lenses

Newbie so forgive me if I do not follow protocol.

However, I did go by my surplus electronics store today and they had a DLP lens 5:1 that was produced, according to him and fairly creditable guys, by Texas Instruments for a prototype project that they eventually killed (there are several TI plants around where I live). They had 3:1, 5:1 and 7:1 lenses. They were about a foot long and the lens was about 5" diameter and terminated at about 1-1 1/2". All machined metal and glass optics. Nice quality and may have had coatings, seemed so to me, althouth not sure. Can these be used in LCD projector and if so, which is best? No writing on the lense besides what I listed was on them but they looked good, not cheap stuff. No focal lengths etc. but after reading all these forums all weekend long (literally never leaving my house for two days) I have the urge to build one of these projectors!! Have always wanted one but budget limited!

 

[slizm]

how much distance will between lcd/fresnels? what size mirrors? How many fans? I'm seriously considering changing my lilliput Pj to this design.

 

[rcabezas]

Nice design, mccamp82, I was thinking about doing something similar. What are your measurements in? metric or imperial?

Thanks,

Raf.

 

[auz_mo]

Hey nice plans!, I have a couple questions for you though if you don't mind...

I haven't actually ever made a projector before, and I'm wondering something about the condensor lens...

Is this just a standard converging lens? and if so, is the first fresnel placed at the exact focal length of the lens?

I know this might sound stupid, but it just seems to me like it would burn a hole in the center of the fresnel, and not throw light anywhere but in the dead center of the fresnel, I just want to know before I start constructing a projector of my own, I have quite the array of lens at my disposal and I just want to know what one to use as a condensor!

Thanks in advance

 

[mccamp82]

Good questions. Thanks for the compliments. I do not the measurements in metric right now, but i will try to calculate them later on tonight.

About condensors. Instead of placing the condensor at the focal lenth og the condensor itself, you will place it at the focal length of the fresnel. You measure from the fresnel to the side of the consendsor that is farthest from the fresnel, and you measure it out to the focal length of the fresnel. In my case it is 8.6 inches.

Hope that helps out.

Take care.

 

[auz_mo]

Thanks, that does help quite a bit actually, one more question though, I know how to get the focal length for a standard lens using this method:

http://www.nasaexplores.com/show_912_student_st.php?id=021230151815

but how could I establish the focal length of a fresnel lens?

 

[rcabezas]

What you describe, auz_mo, would happen if you were to place the condenser at its focal length from the arc of the bulb. But you don't , you place it closer, and then it spreads the beam so that it covers the whole fresnel.

Raf.