High speed mechanical laser shutter

#The present invention relates to a high speed mechanical laser shutter, and more specifically to a fast mechanical laser shutter having high power handling capability and suitable for continuous operation in conjunction with a high-power laser used in industrial processes such as machining, welding, deposition and other manufacturing operations.

#Shutters for selectively interrupting (blocking or diverting) or letting pass the optical output of high power lasers used in industrial processes and manufacturing operations are known. In use, the shutter is moved to either block—and receive the energy of—a laser beam or is moved out of the path of the laser beam permitting it and its energy to be applied to a workpiece or work surface.

#In the past a solenoid-operated shutter has been driven from a closed (blocking) position to an open (unblocking) position by selectively energizing the solenoid. The return of the shutter to its normal closed position has been effected by springs or gravity. The opening and closing times of such shutters have been found to be unequal and difficult to control. Since the amount of energy applied by the laser to a work surface or workpiece is proportional to the time the shutter is open, this lack of control of shutter opening and closing times results in a lack of control over the amount of laser energy applied.

#FIG. 1 is a generalized, perspective representation of a laser machining system which includes a shutter that is usable to pass or intercept a laser beam produced by the system and which also includes facilities for operating the shutter in a predetermined manner; and

#FIG. 2 is a graphical depiction of current pulses which are applied to the actuator of FIG. 1 to operate the shutter.

#Referring first to FIG. 1, a schematic of a laser operating system 100, including a shutter 102 according to the present, are shown. As can be seen the shutter 102 is used in conjunction with a laser (not shown, but indicated at 104), which is preferably a high power (kilowatt level), continuous laser used to machine, weld, deposit materials or perform other manufacturing operations. Suitable lasers include neodynium/yttrium-aluminum-garnet (“YAG”) lasers, though any high power laser suitable for machining, welding, depositing or other manufacturing operation may be used.

#The laser 104 and its associated facilities, including cooling facilities (not shown but indicated at 106), are contained within a housing 108. Shown entering the rear of the housing 108 are power leads 110 to the laser 104 and hoses 112 through which a coolant moves as it is circulated by the cooling facilities 106, as indicated by the arrows 114 The laser 104 maybe selectively operated to produced a coherent light beam 116 which exits the front of the housing 108. The light beam 116 maybe focused by a lens system, generally indicated at 118, to produce a high energy “spot” 120 at a selected site on a work table or stage 122, the focused light being indicated at 116a. A workpiece (not shown) to be machined, welded, or have something deposited thereon rests or is held on the stage 122. As is known, the stage 122 is movable by facilities (not shown) in the “X”, “Y” and “Z” directions to apply the high energy spot 120 on the desired portion of the workpiece, as indicated by the axes 124. Although the stage 122 is depicted in FIG. 1 as vertically oriented and the light 116,116a from the laser as horizontally directed, it is clear that the orientation and direction of either may assume any desired orientation.

#The shutter 102 of the present invention either intercepts and blocks the light beam 116a produced by the laser 104 or permits passage of the beam 116a therepast and onto the workpiece resting on the stage 122. The shutter 102 achieves the foregoing by occupying either a first position 124 (solid outline) which intercepts the beam 116a or a second position 126 (phantom outline) which is located away from the first position 124 so that the beam 116a by-passes the shutter 102 and reaches the stage 122.