Working Principle of Night Vision Focus Lens

A night vision focus lens is an optical system specially designed for

1. Light collection and transmission

   The lens gathers visible light and near‑infrared light (usually 850 nm or 940 nm) from the scene. It uses optical glass with high infrared transmittance to minimize light loss, ensuring sufficient light reaches the image sensor even in dark environments.
2. Focusing and imaging

   By adjusting the relative position of lens groups — either manually or automatically — the lens converges light rays accurately onto the sensor plane. This forms a clear, sharp real image of the target object.
3. Aperture control

   The aperture adjusts the amount of incoming light. A large aperture improves light‑gathering ability, which significantly improves brightness, reduces noise, and maintains clarity in night conditions.
4. Spectral matching

   The lens is coated with special optical coatings optimized for near‑infrared bands. This reduces reflection and improves transmission in the infrared spectrum, enabling effective imaging under infrared fill light.
5. Image projection

   After focusing, aberration correction, and light transmission, the lens projects a well‑formed optical image to the camera sensor. The sensor then converts the optical signal into an electrical signal for output and display.