A purely physical, passive natural light collection and transmission system that operates without electricity during the day, channeling natural light from rooftops through pipes into poorly lit interior spaces of buildings. It is a green building energy-saving daylighting technology. Douyin Encyclopedia.

Three Core Components
1. **Lighting Cover (Roof End)**
PC / Acrylic hemisphere / Diamond-shaped cover body, weather-resistant, impact-resistant, equipped with UV filter layer, collects direct sunlight on sunny days + diffuse light on cloudy days; provides roof waterproof sealing, some with self-cleaning coating.
2. **Light Transmission Tube (Core)**
Cylindrical pipe, the inner wall is ultra-high reflective film (high-end can reach 99.7% visible light reflectivity), light is continuously reflected downward within the tube; can be equipped with bends, can bypass beams and columns, commonly with diameters of 250~750mm, the effective transmission distance can generally reach several tens of meters.
3. **Diffuser (Interior End)**
Diffusion panel on the indoor ceiling, disperses the strong light from the pipe, outputs soft, uniform, non-glare natural light, filters out excessive infrared heat radiation to avoid indoor overheating.

Working Principle
Outdoor natural light is collected by the light-collecting hood and refracted into the light-conducting tube → It is reflected and transmitted multiple times within the highly reflective tube wall → The bottom diffuser evenly disperses the light, illuminating the interior. **Only visible light is transmitted**, filtering out most ultraviolet and infrared rays, reducing the amount of heat brought into the room. Even on cloudy or rainy days during the day, there is still light transmission effect.

Advantages
- **Zero power consumption during the day**: Significantly reduces daytime lighting electricity consumption, lowers air conditioning cooling load, and adds points for green building certification
- **Safe**: No wires, no risk of electrical fires, suitable for flammable and explosive areas such as warehouses, oil depots, and underground garages
- **Healthy**: Natural light, high color rendering, no flickering, improves the lighting environment in enclosed spaces
- **Flexible installation**: Pipes can make short turns, compared to traditional skylights, the roof openings are smaller, and waterproofing is easier to handle
- **Simple maintenance**: Long service life

 Typical Application Scenarios
Underground garages, factory and warehouse buildings, stadiums, schools, hospitals, office corridors, museums, villas, supermarkets, underground passages, etc. - architectural spaces with large depths and lacking natural light from side windows