What is this?

[glatt]

I thought it had one diagonal seam, but it looks like it has two seams. It makes much more sense to me now, considering the paths the 3 light sources must take to combine onto the screen into one image.

[glatt]

Thanks, beauregaardhooligan, for a great "what is this."

[beauregaardhooligan]

Originally Posted by glatt

Thanks, beauregaardhooligan, for a great "what is this."

Thank *you* sir, and everyone else, for riding theCellar.org amusement park.
Please keep all appendages in the car,
and feed the toad.

[beauregaardhooligan]

Nice diagram, glatt.
As for the seam, I'm pretty sure there's just one.
You can see it pretty clearly in the 1st and last nekkid cube pix.

[glatt]

Originally Posted by beauregaardhooligan

As for the seam, I'm pretty sure there's just one.
You can see it pretty clearly in the 1st and last nekkid cube pix.

I think there have to be two seams, otherwise one of the 3 colors won't make it onto the screen. One is very clear in the nekkid cube pictures, but there is a faint hint of another. Maybe I'm just imagining that I see it, but I'm 99% certain it has to be there, so I think it is.

[beauregaardhooligan]

Originally Posted by glatt

I think there have to be two seams, otherwise one of the 3 colors won't make it onto the screen. One is very clear in the nekkid cube pictures, but there is a faint hint of another. Maybe I'm just imagining that I see it, but I'm 99% certain it has to be there, so I think it is.

I'm guessing that is an internal reflection of the seam within the prism?
I'll look more closely when I get home.

[xoxoxoBruce]

I thought a dichroic mirror passed, and reflected, half the light... but not so.

A dichroic filter or thin-film filter is a very accurate color filter used to selectively pass light of a small range of colors while reflecting other colors. By comparison, Dichroic mirrors and dichroic reflectors tend to be characterized by the color(s) of light that they reflect, rather than the color(s) they pass.

Thanks for the edumacation, Beau.

[beauregaardhooligan]

Thanks, xoB!
I got a chance to ask our service tech, and he said that it *does* break the light down into RGB for the LCDs, and the prisms put it back together.

glatt, you were right, there *are* two seams.
The cube is made from 4 prisms.
Then I got to thinking about the dichroic coating and if it's just on the internal faces or all sides of the prisms.
{I think it's just internal}
...then I wondered which faces are tinted for which colors.
...then I tried to imagine assembling one and keeping the colors straight
,,,then I boggled at the tolerances required to make such a seam optically perfect.
...then my brain turned into a torus.

[xoxoxoBruce]

Originally Posted by beauregaardhooligan

Thanks, xoB!
I got a chance to ask our service tech, and he said that it *does* break the light down into RGB for the LCDs, and the prisms put it back together.

glatt, you were right, there *are* two seams.
The cube is made from 4 prisms.
Then I got to thinking about the dichroic coating and if it's just on the internal faces or all sides of the prisms.
{I think it's just internal}
...then I wondered which faces are tinted for which colors.
...then I tried to imagine assembling one and keeping the colors straight
,,,then I boggled at the tolerances required to make such a seam optically perfect.
...then my brain turned into a torus.

I doubt the prisms have a Dichroic coating. They are recombining the three colors

But anyway, that's the coolest paperweight ever.

[TheMercenary]

Originally Posted by xoxoxoBruce

I thought a dichroic mirror passed, and reflected, half the light... but not so.



Thanks for the edumacation, Beau.

And I am wondering under what conditions one would use these mirrors. Anyone know?

[xoxoxoBruce]

They separate colors by reflecting one and letting everything else pass through, but except for applications like the projector, I can't think of a use other than jewelry.

[xoxoxoBruce]

Ah, now I got it. I wonder if the first dichroic mirror is different from the second, or if red does indeed get twice the light of the other two colors?

[beauregaardhooligan]

Originally Posted by xoxoxoBruce

Ah, now I got it. I wonder if the first dichroic mirror is different from the second, or if red does indeed get twice the light of the other two colors?

That is beyond my fathoming, xoB. I don't think the light is broken down by the R/G/B colors, but I dunno.
I *do* know that there are some polarized/tinted pieces between 2 of the LCDs and the cube, but most of the refracting/color separation occurs before the LCDs.
It's quite the wonder.
Now they're displaying projectors at the CES the size of an iPod!
DickTracy is right around the corner, folks.
Hold on to your data, it's gonna be a wild ride!