I have been reading most all of the posts on this site for some time and thought that I should post my design model for a high quality projector that I plan to build around a 15" LCD panel.
It can be seen at:
http://groups.msn.com/paul'sdiyprojector
It can be seen at:
http://groups.msn.com/paul'sdiyprojector
My projector site
Several people tried to visit my site and it seems many were not allowed to view the pictures. I set this group site up to be private and I haven't figured out yet how to change the settings so everyone can browse to the site. I wanted it that way so that I could limit the site to those who were really interested. I intend to make the site available to anyone who wants to see it. I tried attaching the pictures to the first post in this thread but was unable to because the images were too many pixels wide. I will see if I can get things going. Thanks for your response.
Several people tried to visit my site and it seems many were not allowed to view the pictures. I set this group site up to be private and I haven't figured out yet how to change the settings so everyone can browse to the site. I wanted it that way so that I could limit the site to those who were really interested. I intend to make the site available to anyone who wants to see it. I tried attaching the pictures to the first post in this thread but was unable to because the images were too many pixels wide. I will see if I can get things going. Thanks for your response.
Access to my DIY projector site
I have accepted all who have requested to join my site so they can view my designs. I will continue this practice. If you go to the link and then apply to be a member then I will approve you in the next day or so.
I have two ideas for manufacturing the large lens and would like any feedback for other cost effective methods.
I have accepted all who have requested to join my site so they can view my designs. I will continue this practice. If you go to the link and then apply to be a member then I will approve you in the next day or so.
I have two ideas for manufacturing the large lens and would like any feedback for other cost effective methods.
Ok, I had to sign up for M$ .NET. I used my old hotmail address. Then I joined your group. I went to check my email and I had to renew my hotmail account. When your group emailed me the password or whatever, it was lost in cyberspace. Now I can't get it to send me a new one.
Personally, if I have to sign up for membership for a site fronted by a single member I don't bother. I think you will get more input with an "open membership" policy, those that aren't really interested don't generally hang about for very long.
zardoz
zardoz
You can resize your design pictures with any photo editing software and post them right here.. It would be easy for those who dont use MSN or Hotmail and less worry about remembering another password.
The other Idea is to just screen capture your existing pages and post them here.
I am interesting to learn your design concept and would much appreciate if you can share it here with us.
Thanks.
The other Idea is to just screen capture your existing pages and post them here.
I am interesting to learn your design concept and would much appreciate if you can share it here with us.
Thanks.
My projector site
I have changed my DIY projector site's policy so that anyone can view the site. If you want to post a discussion there you will have to click on the link to join. Otherwise any discussion can be posted to this thread. Thanks all for you feedback.
I have changed my DIY projector site's policy so that anyone can view the site. If you want to post a discussion there you will have to click on the link to join. Otherwise any discussion can be posted to this thread. Thanks all for you feedback.
The light you call "wasted" is wasted as it passes through the LCD screen. How does the second lens recoup that wasted light?
zardoz
zardoz
dude theres only one person on the site...(lol)..i see no replies. it was a good idea to make it public 🙂. i have to admit the design looks great but its not worth joining a group for. i would join (WOULD) if u had actual pix of this thing working.
umm...
depending on your lcd size, i dunno where u're gonna get a quality glass lens with a diameter that big. i think that's gonna cost you some. i do like the design, though i am sticking to direct projection, 'lay-down' style projector.
depending on your lcd size, i dunno where u're gonna get a quality glass lens with a diameter that big. i think that's gonna cost you some. i do like the design, though i am sticking to direct projection, 'lay-down' style projector.
Wasted light
This is my view on the wasted light I was talking about.
For OHP designs if most of the light is collumated by a fresnel lens before it passes the LCD the light is moving in a straight line. Or at least a large portion of it.
With single lens OHP designs only a smaller portion of the light that passes through the LCD that is defracted at an angle and can project towards a small lens several inces away will be focused by the lens. Much, if not the majority of the light passing through the LCD will go straight out and never by part of the focused image. Further if this light is not blocked out it will wash out the projected image if it's angle of movement is toward the screen.
Second, about the large lens. If a large focusing lens is placed close to the LCD it will capture a much larger portion of the total light output from the LCD and focus that image onto a smaller image which can then be projected by the focusing lens.
The lens need not be made of glass. In fact most large lenses are cast or injection molded out of optical grade acrylic plastic. This is how plastic eyeglass lenses are made. The lens could also be cut on a CNC lathe from a large billet of plastic and then polished and lapped into a superfine finish.
The CNC method would likely yield the best quality lens. I found a site offering optical grade acrylic pellets (which are melted and poured into a mold) for about two dollars a pound. Using this method the mold would be the most difficult thing to make unless one could fabricate one out of a couple of large diameter stainless steel salad bowls or something.
A single billet of acrylic sheet large enough would cost at least 50-70 dollars but the CNC maching would be even more unless you knew a machinist who could do it for you as an odd job.
This is my view on the wasted light I was talking about.
For OHP designs if most of the light is collumated by a fresnel lens before it passes the LCD the light is moving in a straight line. Or at least a large portion of it.
With single lens OHP designs only a smaller portion of the light that passes through the LCD that is defracted at an angle and can project towards a small lens several inces away will be focused by the lens. Much, if not the majority of the light passing through the LCD will go straight out and never by part of the focused image. Further if this light is not blocked out it will wash out the projected image if it's angle of movement is toward the screen.
Second, about the large lens. If a large focusing lens is placed close to the LCD it will capture a much larger portion of the total light output from the LCD and focus that image onto a smaller image which can then be projected by the focusing lens.
The lens need not be made of glass. In fact most large lenses are cast or injection molded out of optical grade acrylic plastic. This is how plastic eyeglass lenses are made. The lens could also be cut on a CNC lathe from a large billet of plastic and then polished and lapped into a superfine finish.
The CNC method would likely yield the best quality lens. I found a site offering optical grade acrylic pellets (which are melted and poured into a mold) for about two dollars a pound. Using this method the mold would be the most difficult thing to make unless one could fabricate one out of a couple of large diameter stainless steel salad bowls or something.
A single billet of acrylic sheet large enough would cost at least 50-70 dollars but the CNC maching would be even more unless you knew a machinist who could do it for you as an odd job.
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