The safety light curtain consists of a projector and a receiver. The projector emits modulated infrared light, which is received by the receiver to form a protective net. When the object enters the protective net and the light is blocked by the object, the receiving circuit immediately responds through the internal control circuit, that is, a signal is output in the output part for emergency braking of machine tools such as punches and presses. Light curtains have a wide range of applications. For example, if the contact safety door is installed on the stamping equipment that needs to send and receive materials continuously, the operator needs to open and close the door frequently, which not only increases the workload of the operator, but also reduces the production efficiency. In this case, gratings and light curtains are the best option. As long as any part of the body blocks the light when the operator is transporting and picking up materials, the machine will go into a safe state without harming the operator.

The density of the beam determines how well a body part can pass through the light curtain before being detected. According to ergonomic data, the diameter of the fingers of an adult should be no less than 14 mm, the thickness of the palm should be no less than 30 mm, and the diameter of the wrist should be no less than 40 mm. For example, if the distance between the optical axes of the light curtain used is 40 mm, the diameter of the optical axis is 20 mm, and the resolution is 4020=60 mm, the hand, palm, wrist and arm can pass through the light curtain without being detected. Therefore, if we want to achieve higher security, we need to use higher resolution light curtains.

When using light grids and light curtains, there are certain requirements for installation. People are not allowed to bypass the grating and light screen to enter the hazardous area, and there is no surface reflection light near the grating and light screen, so the receiver can receive the reflected light but cannot output the safety switch signal. In addition, there are certain requirements for the use environment of gratings and light curtains. If there is too much dust in the environment, it will affect the emission of light, thus affecting the use of gratings and light curtains.