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Spectral range TMP006, a non-contact infrared (IR) sensor

Sonnik Clausen
Prodigy 10 points
Other Parts Discussed in Thread: TMP006, TMP007

According to specification is the spectral range limited to 4 - 8 microns of the TMP006 sensor. The thermopile is basically sensitive in a much large spectral range that open up other applications and more accurate temperature measurements, e.g. the 8 - 14 micron range is the prefered range for surface temperature measurement to avoid problems with absorption effects due to H2O and CO2 in the air (reading affected by humidity). The 8 - 14 micron range gives more accurate temperature measurements at temperature below ambient (from theory & practise), e.g. temperature of food.

1) why is the spectral range limited to 4-8 microns?

2) Is it possible to get the sensor  without any optical filter in front of thermopile? or custom specified spectral range (e.g. 2 - 6 microns has my interest)?

 

 

  • 0
    TI__Mastermind 27715 points

    Hello Sonnik,

    1) why is the spectral range limited to 4-8 microns?
    The range of the TMP006 is limited to 4-8μm due to the silicon cover which sits above the sensor. In order for the TMP006 to be easily manufacturable and relatively low-cost the cover was made out of silicon using standard design processes, and the 4-8μm response is the result of that design.

    2) Is it possible to get the sensor without any optical filter in front of thermopile? or custom specified spectral range (e.g. 2 - 6 microns has my interest)?
    At this time we do not offer a "bare" device, nor do we plan to design a device with a different spectral range.

    Best regards,

    Ian Williams
    Linear Applications Engineer
    High Performance Linear and Sensing Products 

  • 0 in reply to Ian Williams
    Prodigy 10 points

    Hi, I'm also interested in the TMP006 spectral response


    I'm working on environmental sensors to monitor atmospheric emitted radiance, so I'm particularly interested in the response of the TMP006 in the so-called "atmospheric window", between 7 an 14 microns

    I understand that, considering how the sensor is built, it "looks" through a silicon layer (some hundreds of microns thick, I suppose, since the package is 0.6 mm), and that the provided spectral response curve comes mainly from the transmission properties of this silicon layer.

    Now, for what I know the silicon infrared transmission curve has a sharp cut off between 1 and 2 microns due to band gap absorption, and then a phonon absorption band in the far infrared between 7 and 14 microns.

    But, for a silicon layer some hundreds microns thick, the far infrared band should let pass still more than 40% of the incoming radiation, and the short wavelength cut-off should be lower than 4 microns... so I do not understand exactly the origin of the provided spectral response, that also appears very symmetric and smooth, like that of a bandpass filter (that, if I understand well, is not built in the sensor...)


    thanks in advance, and best regards


    Giovanni Bianchini

    researcher, atmospheric physics

    Istituto Nazionale di Ottica

    Firenze, Italy

  • 0 in reply to Giovanni Bianchini
    TI__Expert 3370 points

    Hi Giovanni,

    The spectral range in the TMP006 data sheet is not correct. The correct spectral range is given in the TMP007 data sheet, http://www.ti.com/product/tmp007?keyMatch=TMP007&tisearch=Search-EN, Figure 1.

    Regards,

    Werner Metz