News Column

Patent Issued for Optical Switching System

May 21, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventor Miller, Kirk A. (Dallas, TX), filed on December 30, 2011, was published online on May 6, 2014.

The patent's assignee for patent number 8717692 is Raytheon Company (Waltham, MA).

News editors obtained the following quote from the background information supplied by the inventors: "Modern tactical aircraft use a number of imaging aids to assist the crew in viewing a scene, selecting targets in the scene, and directing weapons against the selected targets. Visible, infrared, and/or specific spectral bands imaging devices are used in various applications to form an image of the scene. The type imaging spectrum depends upon the mission, weather conditions, the nature of the scene, as well as other factors.

"The field of view of an imaging device, used to form the image of the scene, describes the range of the captured scene. A wide field of view allows the imaging device to capture a large area of the scene. In turn, a smaller field of view captures less of the scene, allowing the image device to 'focus in' on the image, and may further help to discern small features within the image.

"Multi-spectral targeting systems may use both infrared and visible light imaging sensors and may include multiple different optical systems suited for use with each type of sensor. For example, optical system used with an infrared image sensor may not be suitable for use with a visible light image sensor. Additional optical systems may be included in the multi-spectral targeting systems for capturing images with different fields of view. Further, it may be desirable to quickly switch between different optical systems. For example, the multi-spectrum targeting system may capture multiple images of the same scene using different field of view optics and/or optics optimized for different spectral bands."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventor's summary information for this patent: "As described above, switching between different optical systems with different field of view or those optimized for different spectral bands may be needed in multi-spectral targeting systems. Conventional switching optics systems include one or more optical lenses, a focus lens, a mechanism for moving different lenses included in the optical system, and a control system, with control software, for directing the mechanism to move one or more of the optical lenses into the optical path of the focus lens. For example, the control system may direct the focus lens to move away from the optical lenses, creating clearance for one of the optical lenses to move into position. The control system may then direct one of the optical lenses to switch into position aligning with the focus lens. As the optical lens moves into position, the control system directs the focus lens to move back to complete the optical path. Because the control system coordinates the timing of each of the movements, there is an overall reaction time associated with the system. In other words, there may be a delay between receiving a command to switch and the completed the switch from one position to another. The longer it takes for the lenses to move between positions, the longer the overall reaction time. Because of coordinated movement the reaction time in conventional systems makes them unsuited for use in multi-spectral targeting systems. In addition, in conventional systems, if the command from the control system is not properly timed, there is potential for damaging either the focus lenses or the optical lenses during the coordinated movement.

"Therefore, aspects and embodiments are directed to a rotating optical switching system that allows for fast switching between optics without coordinating with a control system and without additional complexity. According to one embodiment, the optical switching system comprises a rotating cam device coupled to a field of view optic system and is configured to push a focus cell assembly away from the field of view optic system. The rotating cam device presents an effective solution that reduces the complexity of the switching system, by decreasing the number of mechanical parts needed to switch between different field of view optics. The optical switching assembly, as further described below, reduces the optical system switching time and further, diminishes the likelihood of damaging the optics from manual manipulation of system. In addition, the cam device allows for automatic switching of the field optics without the need to train assemblers or test technicians on the proper manual operation of the optical switching assembly, as discussed further below.

"According to one embodiment, an optical switching system comprises a focus cell assembly disposed in a plane, a rotatable field of view optic system having an axis, configured to rotate around the axis, the axis disposed in parallel to the plane of the focus cell, and a cam device mounted to the field of view optic system and configured to push the focus cell assembly away from the field of view optic system with each rotation of the field of view optic system.

"In one example, the cam device has a truncated circle shape including a plurality of truncations and the plurality of truncations define an optical prescription of the optical switching system. In addition, the field of view optic system may include a plurality of sides and further includes a plurality of optics disposed on the plurality of sides.

"In one example, the plurality of optics may include a first lens cell, a second lens cell, a third lens cell, and a fourth lens cell and the plurality of sides may include four sides. In this example, the first lens cell, the second lens cell, the third lens cell and the fourth lens cell are disposed on each of the four sides of the field of view optic system, respectively. In another example, the cam device includes a plurality of un-truncated portions and the plurality of un-truncated portions push the focus cell assembly away from the field of view optic system during each rotation.

"In another example, the optical switching system further comprises a gear system in contact with the cam device and configured to rotate the field of view optic system. In addition, the optical switching system may further comprise a focus lead screw coupled to the focus cell assembly and configured to return the focus cell assembly toward the field of view optic system after each rotation. In this example, the focus lead screw further includes a helical coil spring wrapped around the length of the focus lead screw.

"In another example, the optical switching system further comprising a focus lead screw nut coupled to the focus lead screw and configured to adjust a distance between the focus cell assembly and the field of view optic system. In addition, optical switching system may further comprise at least two cam followers coupled to the focus cell assembly, configured to roll along the cam device. In this example, the cam followers are configured to prevent the field of view optic system from colliding with the focus cell assembly. In one example, optical switching system further comprises at least one cam stop disposed on the cam device configured to stop the cam device from rotating.

"According to another embodiment, a method of selecting between one of several available in optic modules in an optical system, the optical system includes a field of view optic system, disposed around an axis, a cam device coupled to the field of view optic system and a focus cell assembly disposed perpendicular to the axis. The method comprises rotating the field of view optic system around the axis, pushing the focus cell assembly away from the field of view optic system during each rotation of the field of view optic system, and switching between a plurality of optical states, each rotation corresponding to one of the optical states.

"In one example, the field of view optic system further comprises a plurality of lens cells and switching between the plurality of optical states further comprises aligning one of the plurality of lens cells to the focus cell at each rotation. In another example, the plurality of optical states include a first optical state, a second optical state and a third optical state, and rotating the field of view optic system further comprises rotating the field of view optic system from the first optical state, to the second optical state, to the third optical state.

"In one example, the method further comprises compressing a helical coil spring as a result of the focus cell assembly being pushed away from the field of view optic system, during each rotation of the field of view optic system. In this example, the optical system further comprises a focus lead screw having a length, and the method further comprises returning the focus cell assembly toward the field of view optic system by releasing the helical coil spring. In this example, the optical system further comprises a focus lead screw nut coupled to the focus lead screw and the method further comprises adjusting a distance between the focus cell assembly and the field of view optic system by moving the focus lead screw nut along the length of the focus lead screw.

"In one example, the optical system further comprises a gear system in contact with the cam device, and rotating the field of view optic system around the axis further comprises rotating the field of view optic system by rotating the gear system.

"Still other aspects, embodiments, and advantages of these exemplary aspects and embodiments, are discussed in detail below. Any embodiment disclosed herein may be combined with any other embodiment in any manner consistent with at least one of the objects, aims, and needs disclosed herein, and references to 'an embodiment,' 'some embodiments,' 'an alternate embodiment,' 'various embodiments,' 'one embodiment' or the like are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment. The appearances of such terms herein are not necessarily all referring to the same embodiment. The accompanying drawings are included to provide illustration and a further understanding of the various aspects and embodiments, and are incorporated in and constitute a part of this specification. The drawings, together with the remainder of the specification, serve to explain principles and operations of the described and claimed aspects and embodiments."

For additional information on this patent, see: Miller, Kirk A.. Optical Switching System. U.S. Patent Number 8717692, filed December 30, 2011, and published online on May 6, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=56&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=2785&f=G&l=50&co1=AND&d=PTXT&s1=20140506.PD.&OS=ISD/20140506&RS=ISD/20140506

Keywords for this news article include: Raytheon Company, Aerospace and Defense Companies.

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Source: Journal of Engineering


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