The courtyard robot lens is an optical protective piece installed at the front of the camera module, serving dual functions of light transmission imaging and environmental protection. It is made of high-transmittance coated glass or PC material, with a surface treated with nano waterproof, oil-proof, and scratch-resistant coatings, enabling rapid removal of raindrops, dust, and grass debris. Some high-end lenses feature built-in transparent heating films that warm up within 3 seconds to defrost and defog, ensuring clear imaging during rain or snow. With a surface accuracy of <5 μm, a refractive index of 1.52, and a light transmittance of ≥92%, combined with a 120° wide-angle lens and an infrared filter, it delivers sharp, distortion-free images for visual SLAM, AI obstacle avoidance, and remote monitoring. It serves as the core "eyes" enabling courtyard robots to operate unmanned 24/7.