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Thread: Dichroic from DLP projector wheel ?

  1. #1
    Join Date
    Dec 2011
    Location
    Quebec city
    Posts
    54

    Default Dichroic from DLP projector wheel ?

    I got some parts from a DLP projector and removed the dichroic wheel.

    Does anyone ever tried using these for their dichroic RGB projector?

    Click image for larger version. 

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    I just tried to disolve the glue that retain the 4 dichro to the aluminum disk and left the wheel in aceton for 4 days without significant results... they 4 pieces still seem to be well glued to teh alu disk

    I dont want to cut it with a glass cutter to perserve the larger size as possible and also because it'S round shape...

    Here is their spectrum: Click image for larger version. 

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    Look interesting !! the 532 is right on the center of the bandwidth of one of teh dichro, and the blue and red are ok too for about 96-97%

    Doc
    Pangoline Quickshow FB3
    H-RGB1800 with DT40 and Laserwave OEM pro S modules (r637nm 190mWg532nm 710mWb447nm 850mW)
    Old set of G120 scanners and one Cambridge 6850
    1.4W 445 blue pointer

  2. #2
    Join Date
    May 2009
    Location
    UCSB
    Posts
    681

    Default

    As long as you do not need to keep the motor, you can use heat to melt the glue, I usually use a propane torch for removing optics but I have heard a toaster oven set for 200 degrees works fine as well and doesn't put as much stress on the optics.

    The only problem I see is that they are designed for 16 degrees incidence, and the wavelengths will shift as you change the angle to something more realistic (ie, 45 degrees), generally toward longer wavelengths. I am also skeptical of the plots they provide, there is usually a lot more structure in the reflectance/transmittance of a dichroic mirror, so either they were optimized for a smooth cutoff over best performance, or their spectrometer is not telling the whole story. That said, its at least worth a try

  3. #3
    Join Date
    Dec 2011
    Location
    Quebec city
    Posts
    54

    Default

    OK.. I was worring about heating these dichro, i would not affect the layer....
    I know that they are not made for 45 degree so i will test then at work with angular rotating stage and power meter. I barely tested them manually with a white beam from my projector and they seem to work nice at 45.. but i will test them anyway
    I might also test them for they quality of flatness and transmitted wavefront. I will use a Zygo wavefront sensor. I dont want these dichro to act like a lens for the transmitted spectrum due to possible added divergeance!

    Doc
    Pangoline Quickshow FB3
    H-RGB1800 with DT40 and Laserwave OEM pro S modules (r637nm 190mWg532nm 710mWb447nm 850mW)
    Old set of G120 scanners and one Cambridge 6850
    1.4W 445 blue pointer

  4. #4
    Join Date
    Sep 2009
    Location
    Mexico
    Posts
    473

    Thumbs down

    Hi

    I try DLP dichros from a BenQ (color wheel broken)
    And no good for more than 500mW
    More and start reflect less. at 45 deg. (I think I made a hole in it)

    Cheers,
    Ed

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