Dichroic filters question

[Ideas]

I am building my own RGB projector and am looking for some dichroic filters,

I stumbled upon these from LENOPTEC (anyone heared of them?)



pass BLUE, reflect green and red OOPS I WAS WRONG: it must be REFLECTS BLUE, passes green and red
LINK with specs


AND

pass RED, reflect green and blue OOPS I WAS WRONG: it must be REFLECTS RED, passes green and blue
LINK with specs



Would they suit my needs if I eg would mount them on a MM1 and position them @45°?

Thank you in advance

B

[LaNeK779]

there are a few things i dont get, maybe it is just me

1. the mm1 does not have a hole in the middle, are you going to mount the dichro sticking out from one side for the most part? maybe the mm2 with an 1 inch hole would suit you better

2. can you describe the placement of your lasers? is the red going to be further from the galvos or the closest one? and still, it looks to me that one of the two does not suit you

you need one that passes red and reflects green and another one that reflects blue and passes red and green


or, on a different setup one that passes green and reflects blue and another that passes green and blue and reflects red

depends on what laser you choose to be your "guideline"

[buffo]

Would they suit my needs if I eg would mount them on a MM1 and position them @45°?

Depending on the order of your lasers in the beam path and the layout of your projector, yes, they would work. How are the prices? (Typically dichros sell for $35 each.)

the mm1 does not have a hole in the middle, are you going to mount the dichro sticking out from one side for the most part?

This is actually a common arrangement. It looks funny, but it works just fine. I agree that using the larger MM2 with a hole in the center looks better, but it's also more expensive.

Adam

[LaNeK779]

mr buffo, can you double check the dichro selection? i think the ones posted will not do it for him

[Ideas]

Thanx for the help already!
PS thank you for pointing that out, I see it now that I have a transmission problem after my first blend as part of the blend is reflected by the second dichro.. hmm I should go looking after a second dichro that lets me pass a broader spectrum and only reflects one primary color instead of two..

[LaNeK779]

exactly!!

you can also check online stores from members here, they do carry good quality dichros (much better than the 95% you got)

[buffo]

mr buffo, can you double check the dichro selection? i think the ones posted will not do it for him

If I'm reading the graph correctly, the first one transmits green and red, and reflects blue, while the second one transmits blue and green, and reflects red.

In that case, he can go with the standard layout - green, then mix in red (using the second dichro), and finally mix in blue (using the first dichro).

This assumes that T-ave refers to transmission efficiency on the graphs provided.

If they are reversed (that is, T-ave is actually reflectance, which would be very weird), then you'd put red first and use the second dicrho to add in green. Then for the blue you'd have to reflect the red and green off the first dichro while allowing the blue to pass through, which would complicate the optical layout a bit. (It adds a 90 degree turn to the beam path.) But it would still work.

Truthfully though, it would be best to design your optical layout first, and then buy the dichros you need, rather than buying the dichros and then trying to make your layout match the dichros you bought...

Adam

[LaNeK779]

well, something does not check out

either the graphs are weird, or the description Ideas gave is wrong

i also see in the graphs that the first one passes green and red and the second passes blue and green. but we don't know the behaviour of the second dihcro @ 445

[mophead]

Truthfully though, it would be best to design your optical layout first, and then buy the dichros you need, rather than buying the dichros and then trying to make your layout match the dichros you bought...

I concur. I have a set of dichros that was bought before the lasers. They *will* work, but not as well as they should knowing the light sources I have now. They can be used for a different purpose, but it was money spent without a purpose.