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DLP7000UV: Damage threshold intensity with peak @ 365 nm and tails going below 363 nm

Part Number: DLP7000UV
Other Parts Discussed in Thread: DLP9500UV, , TEST

The spec sheet for DLP7000UV & DLP9500UV says the damage threshold is 2.5W/cm2 from 363-400 nm and the threshold drops suddenly to 2 mW/cm2 below 363 nm. I was wondering if the damage threshold drop is sudden (like a cliff) or more like a gradual drop (over 20-40nm). The window transmittance curve shows a gradual decrease in transmittance and not a sudden reduction by 3 orders of magnitude (http://www.ti.com/lit/ds/symlink/dlp7000uv.pdf). 

I would assume the objective of this damage threshold from 363-400 nm is to capture the 365 nm peak of typical UV lamp spectrum (its tails go below 365 nm). So, if using a mercury lamp source with 365 nm peak & some tail below 363nm, these DMDs should still be okay upto 2.5 W/cm2 ? Is my assumption correct ? Or the tail (< 363 nm) of the 365nm lamp peak would damage the DMD if intensity goes above > 2mW/cm2 or how much degradation in life should we expect. Any clarifications/ variation of life with intensity & wavelengths plots etc. would be helpful.

Thanks,

Nilabh

  • Nilabh

    Thanks for your E2E question.

    The data sheet optical power density specification for wavelengths between 363 and 400 nm were determined during the DMD design and qualification processes.

    The UV test equipment used at that time did not have significant optical power below 363 nm, and that limited the optical power density values that could be specified in the datasheet.

    I recommend you read and follow the guidelines in System Design Considerations Using TI DLP® Technology in UVA (363 to 420 nm) DLPA060

    If your design ensures that it implements and follows the design guidelines, optical wavelengths below 363 nm can be used with the DLP7000UV and DLP9500UV DMDs.

    You can contact me directly if you have more questions regarding using DLP technology for lithography applications