The Effects of Reflector Design and Lamp Orientation

[ace3000_1]

just one question more, in that spherical picture, why does he stop drawing lines there? he could have drawn a few more. have a look to the image, you´ll see it is half the spherical reflector used.

Hhehehe not sure you could always email them and ask them, imo yeah it is just a drawing for an idea, its not overly acurate. Ive drawn one of a system i designed a while back (see pic below).

The ellipsidal i bought cost me us$100, somewhat a very high quality commercial reflector.

Trev

[Rox]

very good picture yours. It is what i´ll do a swell. so no need to focus light to paralell output....

about that picture, i´ll tell you why , if you draw one more, you wuld see it will not go paralell, it will bend down (drawing upside first), then you can draw next to it another one, it will bend more than the last, and finally the error will be inaceptable.

Now this error goes increasing in the way we go farther and goes decreasing in the why we go left(upside of sphere)), but always there will be this error, the only point where error is 0 is the ray that goes left orizontaly. is returned horizontaly, paralell .
all other rays will have error, (more or less, but always error)

need a pic?

[ace3000_1]

Na i dont need a pic because you can only get the paralelle light from a shperical in a shallow sphere, never in the one that i drew. Telescope mirrors you can for an example , i get what your saying though and your right in a way.

My picture is only on a 1 way axis aswell so its not overly acurate in a 3d world, if i drew one in the otherway you would soon see how bad a spherical realy can be as the light wont go back to the center of the source due to our arcs being miles too big. The only way to have a spherical somewhat distortion free is the have a arc no bigger then 1mm, even then we will still have spherical abberations.

Trev

[Rox]

ok, i don´t need to go further on these r/2 focusing on sphericals.


now, just having a look to your picture, i have masured the diameter and the focal lenth of your condnesor lens (i stated the bulb is 1 inch diameter circle). and found your lens is like; 70mm diameter and should have 4-5 cm focal.

do you have such a lens?

[ace3000_1]

Your close the lens is 65mm dia and 80mm focal

That pic isnt overly acurate, its just to give an idea on how much light i was utilising from the lamp, and even this is questionable as i havnt drawn in any reflections, that all comes under what type of coating used.

From memory the reflectors curvature is out too though its close.

Trev

[Rox]

i´m very interested on your setup, could you tell me bulb lens separation, and tft size as well as back fresenll focal?

[ace3000_1]

Hmm well i dont use that setup no more, the rear frensel was 220mm, the condenser now used (not me but for others) is about 80mm focal and is 80mm in dia, the bulb dia is 25mm and the reflector is 63mm dia.

I got quite a fair bit of my previous setup in my old thread which can be found here:

Ace_3000....pictures of Projector?

Alot of this stuff is outdated now by a long shot as i didnt post up any new stuff for a while, and alot of it ive held back due to time and copyright. Id rather spend more time in testing then posting, and alot of stuff isnt worth posting. Im one of these people who goes in leaps and bounds in R&D , so i could post up a great idea one day and the next i could post up somthing 10x better. So thats why in one way i didnt bother posting all up.

Trev

[Rox]

please ace, you have my mail, could you send me again your last email?

[ace3000_1]

You've got mail

Sorry my tft size is also 7inch.

Trev

[blackout]

Originally posted by ace3000_1
I dont use a condenser on my ellipsidal, why? cos all of the light is going to where i need it, its that simple. I can prove this if you want with a pic of my light on. Its clearly visible. From memory you even drew it out on paper just as i did before i bought it and it all matched up. Why condense the beam more if its spot on where it is? you will end up with a bright center on the projected image.

The only gain you would get with a condenser in this setup is the heh, roughly 5% of light you do loose, its that small its not worth the gain. Hell i hardly see any light on the table other then where it should go, and thats why its so bright, its going where i want it. And thats the key.

Trev

didn't you have to hit the fresnel with the correct angle too?
i think the problem isn't only to get the light on the fresnel, but also to do this according to fresnel's focal length, or you will not have parallel light on the lcd.
i think that using a ellipsidal you have to use a condenser too to adjust the spot-fresnel distance according to focal length...i'm wrong?