Electro-mechanical Shutter for Rapid Optical Beam Blocking
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Solution Overview
Problem
Existing mechanical shutters are inadequate in rapidly blocking optical beams to protect sensitive photodiodes from high-energy pulses, such as those occurring during loss-of-lock conditions in the Laser Interferometer Gravitational-Wave Observatory (LIGO), which can cause damage due to their slow response times and potential for beam clipping noise.
Innovation Solution
An ultra-fast mechanical shutter utilizing a coil with windings of electrical wires within a magnetic field, controlled by electromagnetic interactions to move a mirror and block optical beams, achieving 90% closure within 1 ms and 99.9% closure within 2 ms, with a backup mechanical stop mechanism and a beam dump to absorb pulse energy, thereby preventing damage to photodiodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If existing mechanical shutters are used to block optical beams, then the structure is simple and reliable, but the response time is slow and beam clipping noise occurs
Solution Approach 1:
The patent replaces traditional mechanical shutter systems with an electro-mechanical actuation system using coils and magnetic fields. The coil assembly generates electromagnetic force to move the mirror assembly, eliminating the need for complex mechanical linkages, springs, and friction-based mechanisms. This substitution achieves ultra-fast response times (90% closure within 1 ms) while maintaining structural simplicity through direct electromagnetic actuation.
2Reliability
If mechanical shutters operate at high speed, then photodiodes are protected from high-energy pulses, but beam clipping noise may occur
Solution Approach 1:
The patent designs the mirror assembly with specific geometric parameters and positioning mechanisms that ensure the mirror surface precisely covers only the necessary portion of the optical beam path. The mirror dimensions, orientation, and travel distance are optimized to block high-energy pulses reaching photodiodes while maintaining proper beam alignment. This localized precision control prevents beam clipping noise by ensuring the mirror edge does not intersect the beam profile during rapid movement.
3Speed
If the shutter uses electromagnetic actuation for fast response, then closure speed increases, but energy consumption increases
Solution Approach 1:
The patent employs pulsed electromagnetic actuation where the coil assembly receives brief, high-current pulses only during the critical shutter transition periods (opening or closing). During the stationary open and closed states, the coil is de-energized or maintains minimal holding current. This periodic activation pattern enables ultra-fast response times during transitions while significantly reducing overall energy consumption compared to continuous actuation systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The shutter effectively protects photodiodes from high-energy optical pulses by rapidly blocking beams, ensuring minimal damage and maintaining instrument sensitivity, with a designed aperture to avoid beam clipping noise and a long operational lifetime of 10,000 cycles.
Implementation Method 1
at least one coil, comprising windings of electrically conducting wires, the at least one coil configured to move between the upper part and the lower part of the electro-mechanical device
Data Source
AI summary
An electro-mechanical shutter is described. The fast operation is based on a coil operated via a current, where the coil can move within a set of magnets to provide opening and closing of a shutter. The shutter can comprise a mirror connected to the coil, so that the mirror can be moved into the path of an optical beam. The mirror can block the beam light in the closed state, and allow the beam light in the open state.