Back to results
US 6,472,657 B1Granted
Laser synchronized high-speed shutter for spectroscopic application
AssigneeSandia Corporation
InventorsPaul C. Miles, Eldon L. Porter, Thomas L. Prast, Duane A. Sunnarborg
Life of this patent
Estimating the term…
Abstract
A fast mechanical shutter, based on rotating chopper wheels, has been designed and implemented to shutter the entrance slit of a spectrograph. This device enables an exposure time of 9 μs to be achieved for a 0.8 mm wide spectrograph entrance slit, achieves 100% transmission in the open state, and an essentially infinite extinction ratio. The device further incorporates chopper wheel position sensing electronics to permit the synchronous triggering of a laser source.
Claims19
A high speed shutter mechanism for synchronizing the operation of an external device, comprising:
- a high speed wheel, comprising:
- a first disk, said first disk having a first narrow, rectangular opening, said opening having a length and a width, said opening extending along either side of a radius of said first disk;
- and
- a central shaft fixedly attached to said first disk about which said first disk rotates;
- and
- a fixed mask, comprising:
- a second narrow, rectangular opening, said second opening having a length about equal to, and a width less than to about equal, said first opening, said mask arranged above and in a first plane parallel to said first disk such that when said first disk rotates said first and said second openings align along said first disk radius once with each rotation;
- a low speed wheel, comprising:
- a second disk, comprising gear teeth disposed along an outside parameter of said second disk;
- a central shaft fixedly attached to said second disk about which said second disk rotates;
- a large slot, said slot comprising a sector of an annulus of said second disk wherein said sector has a width wider than said first opening, said large slot extending on either side of a radius of said second disk, said second disk lying in a second plane parallel to said first plane, said first opening and said large slot aligning with said second opening every mth rotation of said high speed wheel when said high speed wheel rotates at an angular speed which an integer multiple, m, of an angular speed of said low speed wheel;
- and
- means for simultaneously driving the rotation of said high speed wheel and said low speed wheel, comprising:
- an electric motor, said motor having a drive shaft and first and second spur gears fixedly attached to said motor drive shaft;
- and
- a third spur gear fixedly attached to said central shaft of said high speed wheel, wherein said first spur gear engages said third spur gear, and said second spur gear engages said gear teeth along said low speed wheel parameter.
13 more elements
A high speed shutter mechanism for synchronous laser spectroscopy, comprising:
- a high speed wheel having an axis and a peripheral edge distal to said high speed wheel axis, said axis comprising a shaft about which said high speed wheel rotates at a first speed, said high speed wheel further having a narrow rectangular first slit extending to either side of a first radius from a point near said high speed wheel periphery to a point between said wheel periphery and said high speed wheel axis;
- a fixed mask having a second narrow rectangular slit, said second slit having a width equal to, and a length less than, said first slit, said mask arranged above and in a first plane parallel to said high speed wheel such that when said high speed wheel rotates said first and said second slits align along said first radius once with each rotation;
- a low speed Wheel having an axis and a peripheral edge distal to said low speed wheel axis, said low speed wheel axis comprising a shaft about which said low speed wheel rotates at a second speed, said low speed wheel having a large slot, said large slot extending on either side of a radius of said low speed wheel from a point near the periphery of said low speed wheel to a point between said periphery and said low speed wheel axis;
- said slot comprising a sector of an annulus of said low speed wheel wherein said sector has a width which is wider than either of said first or said second slit, said low speed wheel arranged between said high speed wheel and said mask in a second plane parallel to said high speed wheel such that when said high speed wheel and said low speed wheel rotate said first slit and said slot align with said second slit only every mth rotation of said high speed wheel, wherein m is an integer multiple of said first speed divided by said second speed;
- and
- means for simultanously driving said high speed wheel and said low speed wheel, wherein said means comprises:
- an electric motor, said motor having a drive shaft and first and second spur gears fixedly attached to said motor drive shaft;
- and
- a third spur gear fixedly attached to said shaft of said high speed wheel, wherein said first spur gear engages said third spur gear, and said second spur gear engages gear teeth disposed along said peripheral edge.
6 more elements
Dependencies are inferred from the claim text.