US Government as Represented by the Secretary of the Army

USA as Represented by Secretary of the Navy

Jay N Vizgaitis

Bruce M Pixton

Jasbinder Singh Sanghera

Shyam S Bayya

Daniel Joseph Gibson

Vinh Q Nguyen

Russell S Draper

An optical system that images a scene at two different fields of view, with switching between fields of view enabled by switchable mirrored surface is disclosed. A voltage change across the switchable mirror element generates a change in the reflection and transmission properties of the element, such that the element switches between a mirror state and a lens state. When nested in an annular reflective optic system of a given field of view, the switching element enables the opening of an additional optical path through the center of the reflective optics where a set of refractive optics are assembled into an imaging system for a second field of view. This dual field-of-view system changes field of view with no mechanical movement.

Compact wide field-of-view optical imaging method capable of electrically switching to a narrow field of view

Dual field of view annular folded optics with switchable mirrored surface

A compact multispectral imaging system comprising a set of optical elements capable of simultaneously focusing light from one or more spectral bands (SWIR, MWIR, and LWIR) to a common focal plane and a detector capable of capturing the multispectral image, wherein the optical elements comprise optics made from new optical materials or in combination with existing optical materials that transmit in multispectral wavelength regions.

Multispectral imaging system comprising new multispectral optics

An all-refractive optical system that images a scene at two different fields of view or FOVs, with switching between FOVs enabled by switchable lens elements is disclosed. The two fields of view vary in focal length by a factor of three. The wide FOV images broad-band Short Wave InfraRed SWIR radiation at an f/number of 1.7, while the narrow FOV images narrow-band illuminated SWIR at f/4.9. A voltage change across the switchable lens elements generates an optical power change between finite focus and infinite focus. Situated among static optical elements, the switching elements enable FOV changes with no mechanical movement. The given f/numbers at each FOV are a result of a fixed aperture in the system. The smaller throughput in the narrow FOV mode is augmented by narrow-band illumination of the scene to maintain equivalent sensor response between the two FOVs.

Dual field of view optics with non-mechanical switching

A continuous zoom lens arrangement can image MWIR and LWIR spectral bands to a common image plane. Such an exemplary optical system comprises eight infrared imaging lenses that all transmit over the wavelengths 3.5-11.0 microns and form a collocated image plane for the MWIR and LWIR spectral bands. The lens has six stationary lenses, and two lenses that move in an axial fashion. A cold stop inside the dewar can act as the aperture stop of the system and control the stray light from reaching the FPA. The pupil is reimaged from the cold stop to near the first lens of the system to minimize the size of the lens.

Dual spectral-band optical lens imager

A dual field of view, all-refractive infrared optical system that images the mid-wave infrared light in one field of view and the short wave infrared light in the second field of view onto the same detector. The two fields of view vary in focal length by a factor of six. The narrow field of view images the SWIR radiation at a slow f/number of 10.0 while the wide field of view images the MWIR radiation at f/1.9. The field of view is changed via a single lens that changes its axial position within the lens, resulting in an axial zoom. The change in focal length and f/number at the same time enables an increased focal length without having to increase the aperture size by the ratio of the focal length change, but rather by the ratio of the focal length change divided by the ratio of the f/number change.

Dual field of view multi-band optics

An all-reflective afocal lens is comprised of eight-reflective mirrors which can fold the light path into a very compact and thin configuration while maintaining diffraction limited performance. Such an afocal arrangement is usable with a traditional optical imager of an appropriate aperture dimension and FOV range, or with an annular aperture optical system with the appropriately scaled aperture and acceptable FOV angles. When combined the resulting FOV is scaled by the magnification produced by the afocal. The afocal arrangement can be used in either a magnification mode or a demagnification mode. Such an afocal arrangement can be used as either a focal length extender or as a FOV switch enabling a very short length two FOV multi-spectral system with a length that can be an order of magnitude shorter than a known optical system.

Multi-field of view annular folded optics

Dual band infrared continuous zoom lens

A two fields-of-view system has both fields of view imaged simultaneously to the same image plane. For example, an optical system comprising of two or more FOV where a common dual band focal plane array is used in order to image both spectral bands independently. Each spectral band is passed through a common imager, but split off by a beam splitter so that each spectral band sees a different field of view centered at the same point. The two fields of view are separated spectrally but enabled to be imaged simultaneously due to the spectral separation of the focal plane array and the use of a beam splitter. Such a system allows viewing two fields of view simultaneously.

Simultaneous dual band dual FOV imaging system

A dual mode mirror imaging system is described having a Cassegrain-type objective assembly having a primary mirror with a hole in its center and a secondary mirror spaced in front of the primary mirror, and imager optics disposed in the hole. The secondary mirror is adapted to receive laser wavelength light and infrared wavelength light reflected from the primary mirror and to reflect the light back through the imager optics to focal plane. The secondary mirror has one reflecting surface for the laser light and another reflecting surface for the infrared light. The pair of reflecting surface is positioned to change the optical path length between the laser light and the infrared light so that the laser light and the infrared light are imaged at the same focal plane without defocusing.

Growing community of inventors

Alexandria, VA, United States of America

Jay N Vizgaitis