VL53L1 family IR bandpass filter information

[DKim.13]

ST say that VL53L1 family integrates a SPAD (single photon avalanche diode) array, physical infrared filters ...

​If I use this sensor in close proximity with a device that emits light at a wavelength of 850 nm, I need IR filter information to predict how much this sensor will be affected by light at a wavelength of 850 nm IR.

If I can clearly see the optical performance like the product in the link below, I will be able to find out what needs to be done with or without the 850 nm device.

​https://midopt.com/filters/bn940/

But at least if I can know the center wavelength and FWHM information for the IR filter of the VL53L1 family, it would be very helpful for me to make the device.

Thanks in advance to STMicroelectronics engineers.

[John E KVAM · Accepted solution]

I don't think that's true. The VL53 family operates at 940nm and it has a VERY narrow filter already on it.

The SPAD (photon detector) does not discriminate on the frequency of light, so the bandpass filter is built in.

Our bandpass filter is 940nm +/- 10nm.

The 850nm light will not be a problem. However I've been told that if the LEDs heat up a lot they will increase in frequency. One would have to check if your LEDs can very that much. Choose LEDs that will not get above 930nm light and you will be fine.

[DKim.13]

Thank you for your correct and kind answer.

The problem is that 940nm +/- 10nm was not documented anywhere.

The reason I had to know the filter information applied to the sensor is that the spectrum of a light source with a wavelength of 850 nm is a controllable element. As you know, a typical LED light source has a much wider FWHM than a VCSEL. So, some 850nm wavelength LED light sources can affect the VL53 family. To confirm this, it is necessary to overlap the spectral component of the light source and the pass spectral component of the filter applied to the sensor at the same time.