Leevonk writes – “Here’s how to change your webcam so it can see in the dark. The CCDs of all digital cameras are responsive to infrared light (IR) as well as visible light. However, most webcams come with a filter installed to block out IR light. This makes the image less washed out but it keeps you from being able to see in the dark (using IR illumination).” – Link.
Make a night-vision webcam