Hitachi AW251N and Evonik 7D513 HORRIBLE screen
Posted: 30 March 2012 10:32 PM   [ Ignore ]
Joined  2011-09-12
Total Posts:  17
New Member

Hey everyone,
First, I’m designing and constructing a 45” DSI table.  We chose the Hitachi AW251N and the Evonik 7D513 projection layer acrylic.  Upon initial testing, the image looks pretty bad.  I know the image looks pretty good on a cream textured wall with the settings I have.  But on the projection layer, I get images like shown below.  I can’t believe any amount of tweaking (brightness, etc) would fix this blurriness.  It seems to be only half the screen as well (the lower half away from the projector).  The projector is mounted in the black portion directly above the leaves. 

The screen is about 45” diagonal, 16:9 ratio. 1280x720.  Keystone corrected.  The only acrylic layer on is the projection layer.  Any ideas at all?  Experience anything like this?  I’m really not sure if it’s the acrylic, settings, or an incompatibility problem. Appreciate any input. 

Image Attachments
Posted: 30 March 2012 10:39 PM   [ Ignore ]   [ # 1 ]
Joined  2011-09-12
Total Posts:  17
New Member

Probably should have mentioned this as it very well may be the problem.  I have the projector slightly tilted against the wall of the enclosure and corrected in the projector’s software.  The image visually looks flat.

Posted: 30 March 2012 11:37 PM   [ Ignore ]   [ # 2 ]
Joined  2010-01-15
Total Posts:  419
Sr. Member

Shouse, Unfortunately the tilt is exactly the problem.  The Hitachi uses a rounded mirror to throw its image at a very short distance.  This means that you’d have to account for the rounded mirror in any calculations to manipulate the projector placement.  The hitachi is a great projector for small spaces but very unforgiving if you do not mount it either horizontally or vertically.  Just as a test, can you place the projector flat in your housing?  obviously the image won’t line up, but you can verify that the distortion is a result of the odd angle.  Are you bouncing the image in addition to angling the projector?


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Posted: 31 March 2012 05:55 AM   [ Ignore ]   [ # 3 ]
Joined  2007-09-10
Total Posts:  139

It is always a very bad idea to mount a projector at an angle that produces a keystone distortion. While you can use your projector’s keystone distortion correction feature to get rid of the geometric distortion, you will not be able to get a sharp and clear image, because the projector’s projection plane and the physical projection surface are not parallel. The image will always be out of focus (or, to be more exact: it will always have a gradient from sharp to blurry), no matter what you do.