Ben_Tech's Native Widescreen 15.4" 1280x800 High Definition All-Metal - Completed

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Ben_Tech's Native Widescreen 15.4" 1280x800 High Definition All-Metal - Completed

  • Handcrafted from .063 (14 Gauge) anodized aluminum over extruded frame with stainless steel hardware - very thick and rigid material requiring dedicated metal forming equipment - resulting case is as solid as a slab of stone

  • 3M 9550 varifocal triplet lens 290mm-330mm focal (approx. 6'-7' throw)

  • 90mm dia., 305mm focal pre-condenser lens

  • 50mm dia., 24mm focal optical grade spherical reflector

  • 330/220 fresnels 15"

  • IR and UV glass

  • Premium first-surface mirror on handmade bracket

  • Proview 15.4" 16:10 LCD

  • Icecap 400 watt MH electronic ballast

  • Ushio retrofit 400 watt lamp

  • Miniature 12v 1.6amp chassis power supply - 120v input

  • Panaflo 120mm fans x2 with filters and grills - 3:2 intake/outtake pressurization ratio maintained via rpm tuning

  • Independent toggles for fans, lamp and dimmer

  • Easy access is maintained while light leakage is kept to zero via fine tolerance sliding side panels

Interior and results (17 pics, 1.4MB) - note flash flare on metal indicates imperfections that are not actually present:

Interior shot

Interior shot

Interior shot

Interior shot

Interior shot

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Interior shot

Interior shot

Interior shot

Interior shot

Exterior shot

Exterior shot

Result shot

Result shot

Result shot

Result shot

Result shot
 
Nice, I love the build, but the results could use some improvement. The edges are way too blurry... And yes, you should paint the internals black, atleast between the projection lens and the lcd (light box isint a big deal)

Well done!
Cheers man,
Alex
 
Could you post a photo of the corner, all the photos are cut at the edges.

Where do you think the varifocus was when you took those photos at 32cm for instance?

The image looks like if it has a litle barrel distortion (the up outer edge is not square, is like curved as the botton edge, can you confirm this?)
 
The edges are a bit blurred and slightly distorted and dim. Don't get me wrong - it looks pretty good - just not quite as good as my commercial projector yet.

These are pretty much the same issues Minoten is having with his 15.4" widescreen and the 135mm triplet. These panels are a bit wider (13.1") than your typical 15" LCD (about 12").

The barrel distortion on the right-hand side is there in reality - but not nearly as bad as the camera makes it seem. I think the camera exaggerated it significantly, as there is no visible curve to the bottom of the image. It appears flat. The top of the image is very slightly sloped (quite straight though) from the far left-hand corner, all the way to the far right-hand corner of the top. However, I should be able to fix that quite easily in the future. The mirror may be tilted just a bit more on one side than the other, due to a conflict with the chassis.

I'm considering trying to find a different lens at some point.

The throw with the 3M is about 6'-7' to yield an 80" diagonal image. The lens is about 13" from the LCD, including the bounce off of the first-surface mirror. (5" O/C from the mirror, and about 8" O/C from there to the lens for the best focus it seems to be capable of.)
 
Well here again you are using too much angle from the triplet FOV

15,4" diagonal and 13" triplet placement means you are using 61 degrees of field angle. I don´t think this lens will have such a field angle. (i would say it is 45 in the best case). I would say it is the rason of the dim and blurr corners.

Could you post close up photos? (center and then corner if it is posible)
Anyway your results are very good.
 
ben i read you't other thread about the problem with the resolution....so what resolution refresh rate are u running it at??? have you tried a seperate tv tuner or one of those dvd players with vga out put??? what i'm trying to say is anything else apart from your computer?

great results dude!!!!! at the endof the day you have more pixels on the screen than your 1024x768 pj!!!!! (if it is 1024x 768):clown:

ben bruv more pictures...you are setting standards in quality...because you of i was thinking of buying the mag 567 since proview is not available in u.k....nice one...also share more problems.. 🙂 🙂 🙂 😎 :scratch: :scratch: :wave: :wave: :scratch2: :scratch2: :scratch2: :scratch2:
 
DJ: I am running the monitor at its native resolution of 1280x800 via a HTPC with a quality VGA cable.

The stripe motion artifacts I have mentioned previously on this site, while present in the projected image, are thankfully not visible at all while seated a few feet away from the screen.

My only complaint with the LCD is that the colors are not the most vivid available. They tend toward the muted side of the spectrum.

Here is a reprint of my latest on DBG:

Although it is difficult to hold a camera steady enough to take close-up photographs of the screen door (long exposures required), I have taken pictures of the center and the four corners (attached). It is sharper in life.

Most of the screen is now as in-focus as the 'center' photo.

I find that an 80" image is more than large enough for viewing from 5'-8' away, and screen-door effect is not visible even at the 5' distance.

The previous results are obsolete. I'll have to work on some new movie shots.

Here are the attachments (proof of decent focus - not bad for a $25 lens):

Center of screen

Upper Left of screen

Upper Right of screen

Lower Right of screen

Lower Left of screen
 
your throw is 6' foot isn´t it? i found it something short.

did you reversed the lcd so the image is "readable" on the projection? or you are using a nkeystone or a front mirror to reverse it? some lcd lose contrast if are reversed.

your photos are very good, thanks for posting it but it could be that the projectio image is very small? a reference object like a CD would be perfect next time.
 
With a single mirror design the LCD sits as it does stock. Light shining through the back of the panel. So the panel isnt reversed.

And your focus will improve the closer the projector is to the screen. 6 feet isnt too close at all with a 330mm triplet.

The smaller the image the brighter and sharper it will be.

Have you even built a projector Rox?
 
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