Tracing the development of the Raspberry Pi camera lens. First, people started “hacking” the standard camera module by manually removing the IR filter. The resulting applications were widely popular, and the community kept asking about a way to get the camera module without the IR filter to remove barriers, so eventually, Raspberry Pi foundation was able to negotiate with their supplying manufacturer, Sunny, to setup a dedicated manufacturing line that produced the camera modules without the IR filter.
20161210/http://hackaday.com/2013/05/27/adding-night-vision-to-the-raspberry-pi-camera/
20161210/https://www.raspberrypi.org/blog/infrared-camera-you-asked/
20161210/https://www.raspberrypi.org/blog/ir-filter-shenanigans/