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DLPDLCR471TPEVM: Removing the projection lens in order to adapt to a microscope

Fosseprez Charles
Prodigy 20 points
Part Number: DLPDLCR471TPEVM
Other Parts Discussed in Thread: DLPDLCR230NPEVM,

Hi,

My question is about the possibility to remove the projection lens from the EVM in order to access the DMD directly with my own lenses.

Is it possible without too much trouble?

I did before with light crafter EVM2000 and DLPDLCR230NPEVM. Sometimes a pain, sometimes easy..

Do you know for the DLPDLCR471TPEVM and the DLPDLCR3310EVM ?

Best,

  • 0
    TI__Expert 6100 points

    Hello User,

    Please allow the team time to look at your request. We should be able to get back to you next week.

    Best,

    John

  • 0 in reply to John McKnight
    Prodigy 20 points

    Hi John,

    Thanks for you reply.

    Has been a week now, any updates?

    Best,

    Charles

  • 0 in reply to Fosseprez Charles
    TI__Expert 3905 points

    Hello Fosseprez,

    We are currently in talks with our optics experts and will have an answer for you within the next few days at the latest. Thank you very much for your patience.

    Best,

    Maxine

  • 0 in reply to Maxine Cabrasawan
    TI__Expert 3905 points

    Hello Fosseprez,

    Our optics experts shared with us that there should be 4 screws at the base of the projection lens that hold the lens in place. Remove the 4 screws and the projection lens comes off. Some EVMs have tape or RTV where the projection lens attaches to the engine to create a seal around the projection lens, keeping dust from getting inside the engine. The tape or RTV would also need to be cut or taken off to remove the projection lens.

    I've attached a paper about DMD-based LED-illumination microscopy for more information.

    Best,

    Maxine

    srep01116.pdf

  • 0 in reply to Maxine Cabrasawan
    Prodigy 20 points

    Hi Maxine,

    thanks for the reply ! I will then proceed to the test.

    I am a little bit worried by the F-stop of my system in order to avoid the apparition of fringes (See questions:

    https://e2e.ti.com/support/dlp-products-group/dlp/f/dlp-products-forum/281272/dlp-light-commander-into-the-microscope-zoom-lens-system

    https://e2e.ti.com/support/dlp-products-group/dlp/f/dlp-products-forum/778580/dlpdlcr4710evm-g2-color-fringes-with-projection-lens-removed

    )

    Any information about that?

    Thanks for the reference.

    I do not consider this paper as very useful, as despite the cute figure, they do not provide much information their optical setup specifications.

    To my opinion there is plethora of better literature on the topic, if you are interested for future inquiry I can provide them to you.

    I shall have said that I use the device for optogenetics, not for super resolution microscopy.

    Best,

    Charles

  • 0 in reply to Fosseprez Charles
    TI__Expert 3905 points

    Hello Charles,

    The EVMs typically have an F-stop of F/1.7. It is hard to say what the ideal F-stop should be without knowing other optical information about your system. What is your layout, current F-stop, spectrum, camera specs, etc.?

    The fringe visual artifact could be the result of aliasing of the camera sensor when imaging the DMD array directly, an effect similar to the moiré artifact.

    Best,

    Maxine

  • 0 in reply to Maxine Cabrasawan
    Prodigy 20 points

    Hello Maxine,

    Thanks for your reply. Sorry I missed it and just reply now.

    I do not have issue regarding the aliasing of the camera sensor and the DMD array.

    About my setup I use something home made, pretty hard to describe exactly how it is working, I am still confused and I am not an optics guy. But its damn cheap.

    My optical layout from the DMD to the sample is composed of a cheap microscope objective (4x plan) and something similar to a Plossl eyepiece. 

    In order to control the sharpness of the projection, I place a post field diaphragm after the microscope objective that is near the DMD. But if I close my aperture to much, I start to have vertical bands (visible with the eyes) that appears on the projection. I suppose this is because my depth of field is too big and I start to image the optical system before the DMD. 

    Note: I also use light beam from the projection to form an image on my camera sensor by using the red channel (and a red filter in my optical path after the sample)

    Charles

  • 0 in reply to Fosseprez Charles
    TI__Expert 3905 points

    Hello Charles,

    Thank you for the information. We are consulting with our optics experts and will have feedback for you within the next few business days.

    Best,

    Maxine

  • 0 in reply to Maxine Cabrasawan
    TI__Expert 3905 points

    Hello Charles,

    We're experiencing some delays due to the holiday. Thank you very much for your patience!

    Best,

    Maxine

  • 0 in reply to Maxine Cabrasawan
    TI__Expert 3905 points

    Hello Charles,

    When you close the aperture, this reduces the cone of light and doesn’t capture the full uniform illumination of the DMD. In other words, you need the full F/1.7 to capture a uniform image that is produced by the designed illumination.

    The bands you may be seeing are the gaps in between each lens array cell. When you have enough lens array cell sampling in a large aperture (i.e. F/1.7), this gets smoothed out. However, in a small aperture, you are only capturing a small number of lens array cells and may see these bands appear.

    While the projector isn’t designed to operate in this condition, we suggest adding a diffuser in the illumination after the fly’s eye array. While this area may be difficult to access on the EVM, it will help with the homogenization and uniformity of the light onto the DMD.

    Best,

    Maxine