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OPT3004: OPT3004 IR rejection

Denny Huang
Expert 7170 points
Part Number: OPT3004

Hi team,

My customer have some questions about IR rejection, could you help to recommend?

System Setup:

IR light is turned on at Night mode , but after the IR LED is turned on, there is reflected light such as the wall at the near end, and the brightness value of the ALS return is increased.

We will switch back to Day mode and turn off the IR light, and then return to the beginning to turn on the light. , This repetitive action...

The question 

1. Doesn’t OPT3004 filter out the IR spectrum? if IR light is irradiated to OP3004, theoretically there should be no change brightness, right? But how to explain the problems we are currently encountering.

2. Does the OP3004 have any settings that we did not use correctly? So do you see the IR light source?

3. The OPT3004 spec has description “Normalized Transmission Spectral Response of the Chosen Dark Window”, What does this mean? Is it related to receiving infrared light?

Many thanks

Denny

  • 0
    TI__Mastermind 25895 points

    Hi Denny,

    1, You can see the OPT3004 is spec'd to reject all but 0.2% of IR light. However, with extremely high IR it is possible to have a small response from the device. This will also depend on how much lux the customer is reading and also how much IR light they are throwing on the sensor. You can see the IR light is attenuated to a much lower level compared to visible.

    2, Not sure what the question is here, but let me know if the above does not clarify.

    3, This is an application example and spectrum shown is of a dark glass cover and not our sensor. Dark glass will intensify IR relative to visible, but this is not a spec related to the OPT device itself.

    Best,

    Alex