Laser safety cover for optical table

A customer from CEITEC BUT approached us with the fact that he runs a laboratory where he has an optical table with a powerful fs laser Monaco from Coherent. However, this is not the only equipment in the laboratory and the aim was to ensure that the laser could be operated safely so that it was possible to move around the table without the protective equipment that would otherwise be necessary for this type of laser.

At the time the project started, the laboratory already had some protective features in place - for example, a warning light outside the laboratory door. The customer's wish was to connect the new enclosure to the existing safety circuit. A special requirement of the customer was also the way of mounting the enclosure, whose construction was not to be on the floor but suspended from the ceiling of the room in order to maintain access under and around the table.

The basic structure of our enclosure is made of prefabricated aluminium profiles surrounded by alubond plates. Around the perimeter of the enclosure there are a total of 10 sliding doors whose position (open/closed) is monitored by safety switches. The control electronics of the enclosure are connected to the laser interlock, so that it can only be triggered in the basic state if all the enclosure doors are closed. At the same time, the user is alerted to the start of the laser by a light signal directly on the enclosure and a sign outside the laboratory door. This design, together with the two-stage connection of the main safety circuit, makes the Class IV optical laser table a Class I classification.

In addition to this basic use, the safety circuit of the enclosure can be switched to the so-called "service mode". In this mode, the laser remains on even when the enclosure door is opened and its use is thus intended, for example, for laser beam tuning or other experiment adjustments where the laser needs to be active. Switching to the service mode, in which the laboratory falls back to safety class IV, is accompanied by appropriate signalling and also by locking the entrance door to the laboratory with a magnetic lock so as to avoid endangering new entrants to the room