Safety Light Curtain: 5 Things You Must Know In 2023

Safety light curtains play a very vital role in the industrial automation industry for protecting  workers from injury. In today’s article, we will explain from 5 aspects: what a safety light curtain is, how to choose a suitable safety curtain for your applications, advantages and disadvantages, types, and compliance and standards.

Table of Contents

What is a safety light curtain?

A Safety light curtain is a photoelectric safety protector that protects people from dangerous machines such as presses, robotic cells and assembly lines. It is also known by other names such as light curtain, optical guard, presence sensing device, etc. It consists of two parts, one is the transmitter and the other is the receiver. There are many infrared beams between the transmitter and receiver, and the two parts will form an invisible barrier. Once the obstacle is blocked by objects such as human fingers, arms or bodies, the machine will stop running.

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How to choose a light curtain?

To choose the appropriate safety light curtain for your equipment, we need to consider and understand from 6 technical terms: number of optical axes, optical axis spacing, resolution, protection height, total height and protection distance. We will explain them one by one.

1) Number of optical axes is the number of axes formed by the emitter and receiver of the safety light grid.

Number of optical axes

2)Optical axis spacing is the distance between two optical axes is called the optical axis spacing.

Optical axis spacing

3)Resolution refers to the minimum diameter of an object that can be reliably detected by the safety grating.


4)Protection height is the distance from the bottom to the top of the effective protection range of the grating.

Protection height

5)Total height is the distance from the bottom to the top of the grating.

Total height

6)Protection distance is the farthest distance of the grating from the transmitting end to the receiving end

Protection distance

By knowing the above technical terms, it is easy for us to choose the right safety light curtain now. 

Advantage and disadvantages of a safety light curtain


  • Protecting people from harm, reducing risks, and on the other hand, saving money.
  • Easy to install and maintain.
  • It is suitable for small spaces. Since the protection height can be any height, for small spaces, we can choose a safety grating with a small number of optical axes.
  • High reliability.
  • Strong anti-interference ability.


  • The cost might be a little higher and it is not so acceptable for companies on tight budgets.
  • May lose effectiveness due to external factors such as bright light, dust, or moisture
  • Frequent cleaning and maintenance are required.
  • Unable to prevent accidental falling objects.

Types of safety light curtain sensor

Safety light curtains are classified according to their resolution, which is the size of the object that can interrupt the light beam. They range from finger protection (small resolution, generally optical axis spacing is 10 mm), arm protection (middle resolution, which optical axis spacing is 20 mm) to body protection (large resolution, spacing is 40 mm).

Compliance and standards

Safety light curtains must comply with various international safety standards such as ISO 13855 and IEC 61496, ensuring they meet stringent safety and performance standards.


Although safety light curtains are expensive to install, they are still a smart choice for protecting workers from accidents.

Lorentzzi offers a wide range of different types of safety light curtains, all of high quality and affordable prices. Contact us now for the latest prices!

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