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Exposure a Photoresist with a DLP-Chip

Admir Asanoski
Prodigy 115 points
Other Parts Discussed in Thread: DLP5500, DLPC200

 Hi all,

I would like to exposure a photoresist with a DMD-chip. The wavelenght will be about 400nm or a little bit more (420-435nm).

Normally a photoresist need at least a Dose to clear (for example 320 mJ/cm^2). This Dose is depending on power density (mW/cm^2) and exposure time (sec.).
For me its important to know which power density for the light source i can use respectively which power density is allowed for the DMD-chip. If i know it, i can calculate the exposure time for the System (exposure time = dose to clear of the photoresist / power density). At the moment, the absorbed energy of the DMD is not important. I need only to know which power density (for example 10W/cm^2) i can use for the source respectively for the DMD.
The other question is the function of the DMD-chip. If i use for example the DLP5500 can i change the frequency of each mirror (for example half of the mirrors of the chip with 5000 Hz and the other half with 4000 Hz) ?
It is also posible to operate without an pattern rate (for example all mirrors for 1 minute in the position -12° without a rate)?
I hope i could explain my problems respectively my questions.
Thanks in advance!
Best Regards
Admir
  • 0
    TI__Mastermind 30875 points

    Hello Admir,

    I need only to know which power density (for example 10W/cm^2) i can use for the source respectively for the DMD.

    [Sanjeev] Refer to the datasheet http://www.ti.com/lit/ds/symlink/dlp5500.pdf section ABSOLUTE MAXIMUM RATINGS, note 400nm vs 420-235nm the power handling significantly varies, refer to the notes section on how to compute the values.

    If i use for example the DLP5500 can i change the frequency of each mirror (for example half of the mirrors of the chip with 5000 Hz and the other half with 4000 Hz) ?

    [Sanjeev]

    No. Even for 4000Hz the mirror will be switching at same timing as 5000Hz speed. This is because, DMD works on the basic steps of LOAD and RESET. The LOAD step basically loads data under all the mirrors and RESET is when the mirror take position based on the data loaded. Note this process applied even if the data is same b/w two LOAD operations,  the mirrors continuously go through this cycle LOAD-RESET. The DLP5500 controlled via DLPC200 which provides video path or USB/SPI path for sending entire mirror array or bit-plane.

    It is also posible to operate without an pattern rate (for example all mirrors for 1 minute in the position -12° without a rate)?

    [Sanjeev]

    For maximum DMD reliability the mirror expected to be refreshed, refer to the "Operating Landed Duty-Cycle" in the ABSOLUTE MAXIMUM RATINGS table of DLP5500 datasheet.

    So mirrors are refreshed in the current design, are you working on any Product Idea? Based on the business case and need, we can look at options in the system to allow not refreshing mirrors for 1min (this will be by additional customization), if you are interested to discuss please send me a private message, we can discuss more on how we can work out for mutual beneficial.

    Regards,

    Sanjeev