Well, it was about that time to start my blog on my success and many failures. At first I was going to build with a 17" LCD using a CRT lens. After experimentation I learned the term FOV. I could turn the CRT lens upside down and project an image, but would not be able to get the complete 17" panel or have the image all in focus. Then I decided that I should build something that was going to be cheap and that I could learn from along the way.

This is my materials list:

• 2 - PSONE screens (broke the FFC on first, still trying to repair)
• 6" FFC extension cable and zif connectors
• Slide Projector Sled from Surplus Shed
• 3 - ENH-5 bulbs (120v - 250w, 300 Hours)
• Dimmer Switch
• Page Magnifiers
• Computer Fans, 12v power supply
• Other Misc Materials

I wanted my this to be something portable. Using the CRT as a benefit, my first idea was that the case could be 2 to 3 times small in length than a traditional DIY projector. I figured that I was not going to need a front fresnel, no need for front focal length. Since I am using the surplus shed slide projector setup, I did not think I would need a rear fresnel and rear focal length would not be needed either. Here is a picture of my initial setup.

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I was amazed at my first attempts at obtaining a picture. I realized that the picture was round, not a rectangle. Click to view attachment This a shot from Tennis game.

I thought that the reason that the light was not making it through was because of the anti-glare on the screen. I set the kitchen time for 99 mins and 59 sec. Applied water and waited patiently for the time to count down. At around 30 mins, I reapplied the water.

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With the timer off, it was time to try and remove. At first I started to peal up the polar, but this was only a very small portion of the corner. Tried again... Success

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I also did the brightness mod, thought that this would allow more light and make a rectangle picture.

Second test... Round picture. I had started to second guess my self that the CRT lens did not have a FOV big enough for the PSONE Lens. I put my test panel back in to restart my thinking process.

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It is night and day in the same shot, but you can faintly see a square that I drew to the size of the PSONE screen. I knew that I needed a fresnel to collect the light and attempt to spread it evenly over the panel.

Well, I got a Fresnel... Still a round image, but the corners started to come out. I took the left over peices that I had cut and placed them on the each end. SUCCESS! I got a perfect image. So, I ran out real quick and got some more page magnifiers. I cut one down real quick and placed two in there, but this still produced a round picture.

After some thought, I placed the left over ends of the page magnifiers on the ends and got a rectangle picture. To acurally count, there is about 3 fresnals before the LCD and none after. Two full ones, and then two halves. The problem is that I have a couple of lines in my image. I will post the rest of my images.

Shot of the fresnels

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Shot of the inners.

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Shot of my wall that I am protecting on. It is painted a kind of tan/brown color. I image that if I would get even a white sheet the colors would stand out more

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The outside of the unit (temporary)

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Fifth Element Shot

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Classic NES Super Mario Shot

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Here is me standing in the image. The screen size is around 11 feet diagonal. Throw is just over 12 feet. Screen door... well I would say it really is not noticeable if you have your eyes closed or are blind. At this distance and size the pixels are rather large!

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Looks perty good for a PSone LCD. I think if you just got 3 fresnels and cut them down to fit without edges in the middle you would be in good shape, might want to paint the inside of the box balck to make sure light doesn't bounce off the sides and have stray light getting into your projection and reducing contrast. Do you think that th LCD controller will be OK that close to the lamp without protection? Great job.

Does anyone know of a better way to solve the non-lite corners without using halved fresnals?

Painting black is a good idea. I am planning on starting over on my box, same shape, just need to route my airflow better. I think the LCD controller will need some protection. I really have had the chance to enjoy it yet, still trying to get to working.

I like it. A friend is building a PSONE based PJ, so he will dig this too.
Is that a BARCO lens I spy on the front?

I would be interested in the lens you are using also. I tried a couple of CRT lens and both would not allow me to get an even focus. Corners or middle could be focused not both.

Samuraijack, thanks for looking

It is a Delta II-D made by U.S. Precisions Lens. U.S. Precision Lens was acquired by 3M. I did some research because I was trying to find the focal length of the lens. I email 3M and they replied in a couple of days, said it was around 127 to 133.2mm. 133.2mm, very precise in there estimates. I got the lens from an old electrohome projector. It was a green only single gun or the CRT tube red and blue colors were burnt out. I doubt it though, was really old and I think used for when computer screens were two colors, green and not green (black).

Did you try placing the lens directly on the panel? I tried using this with a 17" and fresnel lens. It was kind of weird. Using the lens in the correct direction, I could focus the panel into about a 2" screen, but if I flip it over and used it back wards, I could get an image, but not the whole panel and not all was in focus like you talked about.

Crt lenses can work. I think there is at least one other member that used one. I am thinking of using one. The issue with the corners is probably because the lense has to be for a flat tube. Some CRT projector tubes are curved and some are flat. You have to make sure you get one for a flat tube. I'm surprised the fl of your lens was indicated as ~130mm. Most crt lenses are designed to be just a few to maybe 10mm away from the tubes. They also tend to have next to no field of view as they are big enough to swallow the tube image whole. Some are even designed to have a liquid fill the space between the lens and the tube instead of an air gap. The raster size on a 7" tube is around 5.5" so a flat tube crt lens that uses an air gap will work to throw the ps1 image.

It is hard to tell but it seems like your light engine is what is producing the circle image. This may be because the fresnel you are using is in backwards or because the light is producing a spot beam that isn't matched to the fresnels focus. Did you cut the fresnel so that the center of the fresnel is always at the center of the screen? If you did, then definitely try turning the fresnel around. Lots of other members have put their fresnel in backwards by accident. It seems like you might not have cut the fresnel or matched the fresnel focus with the light source correctly if you can add fresnels to the side and get more light distributed across the panel.

Good luck...

Chrisbballas Thanks for the comments

I thought that the focal length of the lens related to the throw distance. Either way, it works and that is the important part. This lens came off of a flat tube with a liquid and also small air gap. As for the light, I am using a OHP bulb ENH-5. It was easier to wire because it is rated for 120v versus other 82v and 86v bulbs. I did cut the fresnels from the center. Two are cut from the center out. Then I have two excess pieces that I used to get the light focused into the corners. The edges are really jagged and this causes the bright lines down the middle. The pictures show the fresnel circles. I tried placing the ever direction and combination possible and always got the same results. It wasn't until I placed the pieces on the ends that the whole picture would light up. I am planning on cutting a second one, but intend on taking my time to have cleaner cuts.

Hi Newguy...

SJ was right. I am very interested in your design. I've basically got the exact same components as you are using. I'm very glad that someone else tried out the AG removal on a PSOne screen. I'll definitely be giving it a try. Your results look very good. I only intend a screen of about 40" diag. so I'm hoping to avoid the screen door effect.

What are the dimensions of the PSOne scree after it's stripped? I'm designing my box now and am looking for numbers.

I'll be watching! Looks great so far.

AGeek.

Thanks AGeek

The screen with metal frame after striping is around 3 3/4 x 4 5/8. I did the antiglare removal on my first panel before I got to use it. There was a lot of residue left and required some rubbing alchol and cotton balls to remove it. I soaked it for around 3 to 4 hours. The second time, I set the time for basically 100 mins and had better results. Just becarefull on which layer you are pulling up. For future I am planning on a small screen, but it is just conventent to set it ontop one of my speakers and hit an empty wall in the other direction. I have a perfect spot above my tv, but need the figure away to hang it from the ceiling some how. I have 12' ceilings and can't put any lag bolts into the ceiling. I have some ideas just have to work out the details

The throw distance isn't related to the focal length of the projection lens the way you might think. The projection lens is supposed to be focused on the panel so if the fl of the projection lens is 100mm then the panel needs to be 100mm from the lens. That is why I was surprised by 3Ms stated focal length for that lens. CRT lenses are typically placed very, very close to the image upon which they are supposed to be focused so I would have thought the fl of any CRT lens to be very short. Projected image size or throw is dependent upon the projector distance and screen size. Thus all the discussion about throw distance and screen size, "I want a 110" diagonal image from 15' instead of 10'." A shorter fl lens will give a shorter throw for the same size image but it doesn't change the fact you need to put the thing you are focusing on at the fl of the lens. Most people want a longer throw and that is why the pro lens was made. Note the difference in the standard lens fl and the pro lens fl.

Similarly, the focul length of the fresnels is just as important. The focal length of the collimating fresnel needs to match the distance from the fresnel to the light source (the 220mm fl fresnel dictates that the light source be 220mm from the fresnel). If you had a front fresnel its fl would need to match the fl of the throw lens. So based on what you said and looking at your pictures, perhaps your bulb is not at the fl of the fresnel? The other possibility is that the type of bulb you are using usually has a beam or cone angle associated with it. If the beam angle is too narrow, even if the bulb is at the correct distance for the fresnels fl, you won't cover the entire fresnel with light but will instead get a circle of light (like shining a flashlight on it). The extra fresnel pieces may be off setting this by spreading out the light enough to light the entire panel, well enough to see the corners anyway.

It is the fl of the various lenses that dictates the size of the boxes (length anyway).

The corner focus issue is what I was referring to with the crt lenses for flat vs curved tubes- that shouldn't make much if any difference in the light pattern.

BTW, I think your project is coming along nicely and it certainly seems that with a bit more tweeking you will have a very nice small form factor projector. Good work...

Chris thanks for all of the input. I understood the fresnel placement with light and then to the lens. I did not know about the focal length for the lens portion. Basing off of the information that you provided me, I think that the 3M misplaced the decimal point.

For the spot beam light. The flashlight example is right on target. My light is not at the proper focal length for the page magnifiers. I tried moving the light back, forward, up, down. The only thing I didn't try was shinning in the other direction, figured that it would work. I just used multiple fresnels and that seems to work. My next step is get proper airflow.

Some updates:

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I glued in some forms to help line up things and make it more stable. After testing... it didn't work. The first fresnel was way to far away from my LCD. Moved things forward and it worked better.

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Had some heating issues, but this was resolved by adding two fans to the side to blow in over the LCD and then be sucked out through the back. This was a temporary solution. Also pulled the controller board out and placed it on top.

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Time to start building. I build best by cutting twice and measuring... NEVER
I figured that I am going to make it wider to accommodate fans for air movement and taller to place the controller board in a proper spot.

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It is starting to take shape. Planning as I go along is working great.

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Here is a shot of the lamp setup. It is the surplus shed slide projector light sled. I ended up basically cutting everything away except the bulb electrical connector and partial frame to hold the cold mirror in place. Directly above are two fans to vent out the heat. From my previous experiment, I figured out my measurements and cutout slots in some extra MDF to hold my fresnels in place. I also used a toothpick to keep one from sliding around, found it to be very affective.

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This shot show my electrical connections on the left and the air path on the right. Those fans force air in, blows past the LCD and can exit by the electrical connections or move in through the light camber and out through the top section.

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This is from the top, I have a lid that covers this up and reflects away any light leaks. This shows the LCD controller board and the fans that are above the light sources.

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Outside view. It kind of turned into a monster, but it is still portable and is not an eye soar like my one before. My wife and I watch a movie on it last night, even though I can actually measure the pixels on the wall I really like and my wife wants me to start building my 17" version.

Hey Newguy,

Which FCC extension are you using, and did you get special connectors for it somewhere or did you ad-lib it?

AG

PS- Check out my PLOG and tell me what you think!AstroGeek's PLOG!

That's very nice looking!!! I like the scroll work. I just used the standard FCC extension that is available in the lumenlab store. I ordered one from the store, but broke the zif connector. Then i went to Mouser Electronics and order four zif connectors and another 6" extension. I tried super gluing two zifs togther... that didn't work. My solution, I carefully took the brown clip that is on the zif off and started filing down the edge with a finger nail file. Then i filed off some off of the PSONE fcc leed. After several trial and errors, I got them both sandwiched together.

My advice, take your time and be patient. Also, do not try and pull off the tab that is on the PSONE fcc tab. I did that on a 17" panel, worked fine. Tried it on the PSONE and ruined the LCD.

Hope this helps.