psone projector

[DIY BOB]

yes i have completely stripped the lcd.

[Gizmotech]

Let us know what the focal length of your fresnels are. Best way to find out is take it outside in the sun and focus to the smallets dot. (like we burn paper or ants). Make sure the grooved side facing the sun and the flat side facing the floor. Measure the distance to the floor and the fresnel and it should give you the focal length.

Lets say the focal length is 300mm and you have 2 fresnels both identical.

The first fresnel from the lamp (collimator/condensor) should be facing flat side to the lamp, grooved side to the projection lens and should be exactly 300mm away from the center of the element of the bulb.

Then the LCD (backside to the light, and rotated 180 degree) another 15mm from the condensor fresnel.

Then the second fresnel (Collimator/field), groove side facing the bulb and flat side facing the projection lens, another 20mm away from the LCD. Any closer to the LCD will project the grooves onto the wall.

If the Fresnel lens were 300mm, then Idealy the projection lens focal length you need should be about 10mm less than the focal length of the fresnel. The projection lens then is mounted focal length of projection lens away from the LCD and NOT the second Fresnel.

So lets say the focal length of projection lens is 290mm. The lens should be placed 290mm away from the LCD. You might want to use a mirror at 45 degree angle somewhere in between to flip the image over as it will be opposite without it.

You will notice the projection lens will be about 30mm less than the focal point of the second fresnel. That is ok because it gives the opportunity of full use of diameter of projection lens rather than focusing a dot on there. You may even after all this need to make slight adjustments.

Hope this helps. Let us know and post us some pics.

[DIY BOB]

hi gizmotech
the focal length of my fresnels 270mm. and i have managed to get it working. finelly as i have recentlly changed it from a 75w dicloric bulb to a A class projection lamp. i was thinking of getting a MH bulb set up but as i came across the projection lamp i thought i would give it a try and its working well now. i will try and post some pics tomorrow because the camra isant working at the moment.

[mongals]

Truth be told I had the same question about focal lengths because I am building a little dinky pj for the fun of it using the page magnifiers from staples. To test the focal length I took a bright light and sent it through the fresnel, and holding the focus lenses I moved it back and forth until it focused the image of the pen that I had taped on the fresnel. I decided to post this in case someone comes by with the same question.
And I am excited to see some pics of your results( I will be using the psone screen also.)