A safety light curtain is an electronic safety device used to protect people working near dangerous machinery or moving parts. It creates an invisible “curtain” of infrared light beams between a transmitter and a receiver. When any object — such as a hand, arm, or body — interrupts these light beams, the light curtain instantly sends a stop signal to the machine’s control system, halting all motion to prevent injury.
Unlike physical guards, safety light curtains offer non-contact protection. They allow operators to access a machine easily for loading or maintenance while still maintaining a high level of safety. The beams are spaced closely together so even small body parts can be detected. Depending on the model, a light curtain can protect a simple hand-access area or an entire body-access zone.
Safety light curtains are classified mainly into Type 2 and Type 4, following the IEC 61496 international standard. Type 2 light curtains are suitable for low- to medium-risk applications like small assembly or packaging machines, while Type 4 light curtains are used for high-risk environments such as presses, robots, and automated production lines. Type 4 models include continuous self-monitoring and redundancy, ensuring safe operation even if one circuit fails.
In simple terms, a safety light curtain acts as an invisible safety barrier around machinery. It stops dangerous motion instantly when someone enters a restricted area — providing protection without slowing down productivity. This makes light curtains one of the most effective and widely used machine safety devices in industrial automation today.