Fail-safe shutter operation system that safely terminates an electromagnetic wave beam upon interlock action


High-power electromagnetic radiation (ER) beams are usually isolated in an enclosed area guarded by a safety interlock. Opening of the entry point into the protected area causes the interlock to activate a safety system, preventing individuals from accidental exposure to the ER beam. In some systems, the interlock de-energizes the source of the beam, which can cause unwanted delay as it takes time to repower the beam source after it has been de-energized. Thus, ER beams are typically designed to travel along a beam path through a protective housing containing an aperture and shutter at its end. The shutter can move between an open position, which allows the ER beam to traverse the housing and exit the aperture, and a closed position, which blocks the beam from exiting the aperture and is triggered by interruption of the safety interlock. Shutter characteristics differ based on their intended use as well as the type/power of ER beam with which they are to be used; for example, lasers using an interrupted beam to cut industrial goods may need to withstand hundreds of thousands of rapid on-off cycles in normal use, while those intended for safety may only have to endure a few hundred cycles over their lifetime. It would be desirable to have additional options for providing simple, fail-safe shutters, systems, and apparatuses for avoiding accidental exposure to ER beams.

Technology Overview

Researchers have invented a shutter operation device that only depends on gravity to safely block electromagnetic waves (such as but not limited to light, x-rays, and lasers) from going through. The closed position is such that the ER beam is reflected away from the incident beam. Once closed, the shutter can simply be returned to its open position. The device is attached to a standard post/postholder via a standard tapped hole on the bottom of the device, and the laser beam is contained in a standard beam tube.


This invention solves the long-standing problem of how to safely terminate a hazardous laser beam upon interlock action in a fail-safe way and without suddenly interrupting power to the laser power supply, which may damage the laser and turn the laser off altogether. The device can be adapted to different wavelengths, beam diameters, intensities, etc.


Laser or x-ray sources, such as those in aircraft, academic, medical, and industrial cutting applications.

URV Reference Number: 2-20044
Patent Information:
For Information, Contact:
McKenna Geiger
Licensing Manager
University of Rochester
Astrid Mueller
Jeffrey Lefler