DIY LCD Projector Optics question

mbates14

Member
2002-06-02 2:14 am
non
I pulled the optics out of a defunct projection TV, and I noticed the lenses do not have a flat lense to mound the LCD. I played with the optics, and since the lense is cureved, the Picture projected fine, but the focus is bad on the edges and corners, but fine in the middle, How can I fix this?

Projection Lense : Delta 21


here is how the optics were put together:

went from a 5" CRT ---Bowl shaped lens --- Projecter Assembly(delta 21).

I didnt use the bowl-shaped lense, but what is it for?

I didnt use it because it is not flat either. its like the lense on the delta IV, but the back is not flat, its a bowl, but same lens.
 

xblocker

Member
2001-12-20 5:10 am
A lens hasn't to be flat for working! Most lenses have spherical or concave shapes, called convex or convav. If focus isn't archieved over all parts of an image, something is wrong :
1. focal lenght to short
2. aperture too large
3. bad corrected lenses
The phenomen is called spherical abberation and means, outer light rays transmitting a lens have a shifted focus compared to near axis light rays.

xblocker
 
Me thinks,

You have to get a larger Delta lens or a smaller lcd. Some portion of that lens is not useable around the perimeter.

Same with my eyeglasses. The center area is good but the sides are not useable. I think this comes from making an economy lens. It has a smaller area of focus.

I also have the same effect with 35mm zoom lenses of low cost.

It will need a larger working area or a smaller lcd. You may be able to bring the lens closer to the lcd to bring it into that workable area. Give it a shot.

What is the diameter of that Delta and what size lcd are you using?

Bowl shaped lens takes all light hitting flat side and expands it on curved side. And, vice versa.

Maybe try with this lens in there too. It was the original design, maybe it helps.
 

mbates14

Member
2002-06-02 2:14 am
non
I dont have a good enough light yet. I need one of those Flourescent lights that have the 8,0000 lumens, I think there either L. O. A. worklights, or growlights and dont know exactly what there called, but I am just testing the optics I pulled, I got a good projection from an LCD TV, with the original backlight! I was impressed compared to those CRT tvs.
 
I tried companyname but nothing comes up!

I tried brandname too and now my fingers hurt...oooh woe is me.

Do you think maybe they are trying to hide them from us? Hmmm

There is one company called AUO but, it is not in Australlia (AU). It is in Taiwan. Is it maybe this one?

If you can find that companyname again we will give a big smiley face.

Sushibud:D