Bae Systems Information and Electronic Systems Integration Inc.

Bae Systems Information and Electronics Systems Integration Inc.

Michael J Russo, Jr

Mark L Oskotsky

Daniel Engheben

Shawn C Reven

Vincent Lipari

Yueli Zhang

Jerry Ma

Gerard M Perron

David J Korwan

Ian B Murray

Jacinto E Malabuyoc

Morgan Jolley

Thomas Altamura

David Ericson

Erik L Hugel

John J MacEachin

Dipak Banerjee

Christopher V Lipari

A wide angle MWIR F-theta lens with an F# of 2. The lens is deployed on airborne platforms for remote sensing applications. The lens is corrected for monochromatic and chromatic aberrations over the wavelength range 5000 nm-3300 nm. The image of the remote target is formed on a focal plane which may constitute CCD or CMOS with micro lenses. The lens comprises four groups of optical elements with a cold shield/aperture stop located behind the last group. One embodiment of the lens includes five types of optical materials and while another embodiment of the lens includes only two types of optical materials.

Wide angle MWIR F-theta lens

A mid-wave infrared (MWIR) discrete zoom lens for use with remote surveillance and identification having a dual focal length of 9 and 6.39 inches and F #2.8 and F #2, respectively. In one case, a full field of view is about 30.8 degrees for a 9 inch focal length configuration and about 43 degrees for a 6.39 inch focal length configuration. The lens is corrected for monochromatic and chromatic aberrations over the wavelength range 5100 nm-3300 nm. The focal plane may constitute a pixel array consisting of MWIR sensitive material (e.g. InSb, HgCdTe, nBn, SLS, etc.) for use in high-resolution, wide-area imaging applications.

Midwave infrared discrete zoom lens

A Mid-Wave Infrared (MWIR) objective lens having an F # of 2.64 and a 33.6° angular field of view. It is deployed, with a focal plane and scanning system, on an airborne platform for remote sensing applications. Focal length is 9 inches, and the image is formed on a focal plane constituting CCD or CMOS with micro lenses. The lens has, from object to image, three optical element groups with a cold shield/aperture stop. Group 1 has a positive optical power and three optical elements; Group 2 has a positive optical power and four optical elements; Group 3 has a positive optical power and three optical elements. The objective lens is made of two Germanium and Silicon. The lens is both apochromatic and orthoscopic, and corrected for monochromatic and chromatic aberrations over 3.3 to 5.1 micrometers.

MWIR lens for remote sensing

An F-theta lens provides more than 88 degrees FFOV, F #2.8 or less, length not more than 200 mm, and/or 2.5 &#x3bc;m or better resolution, with color correction from 450 nm to 650 nm. The lens includes three optical groups having positive, negative, and positive optical powers respectively, which can include four, four, and six elements, respectively. Embodiments include an aperture stop in the center of the second optical group. Refractive indices and ray heights are selected to correct for field curvature. Embodiments further include a CMOS detector having pixel pitch of 1.25 microns or less, density of 18 megapixels or more, focal plane diameter of 57.2 mm or more, Nyquist sampling of 400 lines per mm or more and wide pixel field of view of 30&#xb0; or more. A plurality of CMOS detectors can be arrayed to create a mosaic image.

Wide field of view F-theta lens

An orthoscopic, apochromatic lens is suitable for deployment such as on aerial platforms provides distortion less than 0.2% over a full field of view of more than 60&#xb0; with F # less than 6.5 and focal length greater than 3&#x2033;, and in embodiments greater than 5&#x2033;. Embodiments are apochromatic from 500 to 950 nm to within 7 microns. Embodiments have an overall length of less than 7&#x2033;. The lens includes five optical groups with an aperture stop between the second and third groups. The optical groups have one, one, two, one and one optical element each, as ordered from the object to the image plane, and have positive, negative, positive, positive, and negative optical powers, respectively. Embodiments are telephoto. In embodiments the focal length is temperature invariant within 0.0015 inches from 0&#xb0; C. to 40&#xb0; C.

Orthoscopic projection lens

A compact orthoscopic lens is corrected for monochromatic and chromatic aberrations over wavelengths from 450 to 2450 nm with an angular FOV of 5.56&#xb0; vertical and 66&#xb0; horizontal. The 4.36&#x2033; effective focal length lens with f-number of 4 is compact measuring 5.2&#x2033; from the first optical surface to the image. The lens includes, in order from object to image, a first optical group having a negative optical power; a second optical group having a positive optical power and a third optical group having a negative optical power. The first optical group consists of two elements, the second optical group consists of three elements, one a doublet, and the third optical group consists of two elements. A physical aperture stop is positioned inside the second optical group. Powers of groups and elements, shapes, refractive indices, Abbe numbers and partial dispersions of glasses are selected so the lens is apochromatic and orthoscopic.

Compact orthoscopic VNIR/SWIR lens

A Compact and Athermal VNIR/SWIR Spectrometer utilizes a slit, a Mangin lens, a pupil lens adjacent to the diffraction grating, corrector lenses, a beam splitter, field lenses and SWIR and VNIR FPAs. In examples, two corrector lenses are used. Some examples do not utilize field lenses and beam splitter, some examples utilize only the SWIR radiation spectrum. By balancing the powers of the optical elements and Abbe numbers of glasses as well as usage of aspheric surfaces combinations, a monochromatic and polychromatic aberrational correction is achieved; by balancing optical elements refractive indices change with temperature an athermalization is achieved. The overall length of the spectrometer does not exceed 4 inches, and in some examples it is 2.5 inches. A wide field of view and a low F number are obtained with an operating wavelength range from approximately 400 to 2350 nm. The spectrometer is particularly suited to airborne applications.

Compact and athermal VNIR/SWIR spectrometer

An off-axis optical system having a rectangular aperture stop to control rays of incident electromagnetic radiation passing through the optical system along an optical path is provided. The optical system includes one or more optical surfaces along the optical path, each surface being configured to change a direction of each ray on the surface based on a location of the ray relative to the surface. At least one of the surfaces is conjugate to and has the same shape as the rectangular aperture stop. In one embodiment, each optical surface is shaped to avoid vignetting the rays. In one embodiment, the optical system is a three-mirror anastigmat (TMA) and includes a concave primary mirror to collect and focus the electromagnetic radiation; a curved secondary mirror to reflect the electromagnetic radiation focused by the primary mirror; and a concave tertiary mirror to focus the electromagnetic radiation reflected by the secondary mirror.

Three-mirror anastigmat having rectangular aperture stop

An airborne hyperspectral scanning system with a reflective telecentric relay including a system housing fore-optics, mounted in the housing, an imaging spectrometer mounted in the housing, the imaging spectrometer comprising a spectrometer slit, the spectrometer slit having an exit side and an entrance side, a focal plane array, a fold mirror, and at least three spectrometer mirrors, ordered sequentially, and in optical alignment with each other, and a reflective telecentric relay, mounted in the housing between the fore-optics and the imaging spectrometer, the reflective telecentric relay comprising a collimator module, a scanning mirror module, and an objective module, the objective module being situated to receive intermediate image from the fore-optics and reflect a collimated beam to the scanning mirror image between the collimator module and the objective module, wherein the objective module is situated to form a telecentric image at the entrance of the spectrometer slit.

Airborne hyperspectral scanning system with reflective telecentric relay

A wide field optically athermalized orthoscopic lens system includes, in order from object to image, a first lens having a negative power, a second lens having a positive power, a third lens group having a positive power, a fourth lens having a positive power and a fifth lens having a negative power. The third lens group includes two lenses having, in order, a first lens with positive power and a second lens with negative power. The powers, shapes, Abbe dispersion values and temperature coefficients of refractive indices of the lenses are selected such that the lens system is athermalized, orthoscopic and achromatized over a wide (e.g. &#x3e;140&#xb0; C.) temperature range.

Wide field athermalized orthoscopic lens system

A compact, lens suitable for airborne photography and mapping has distortion less than 0.6% and is athermal from &#x2212;15&#xb0; C. to +40&#xb0; C. The lens is near-telecentric to less than 11&#xb0;, apochromatic over the wavelength range 450 nm-650 nm, and has a full field of view of 60&#xb0; (high quality field over 53&#xb0;). The lens can be secondary color corrected. In embodiments, the focal length is 101 mm and the back working distance is more than 10 mm. Embodiments have a focal plane diameter of 104 mm and are compatible for use with a CMOS 1.8 gigapixel multiple FPA. In embodiments, the lens comprises three groups of optical elements, with an aperture located within the second optical group. In some embodiments the first group includes two elements, the second group includes six or seven elements, and the third group include three elements. In embodiments the lens (without window) is less than 180 mm long.

Low distortion athermalized imaging lens

A compact F-theta lens suitable for precise mapping and aerial photography has an F# of not more than 4.5 and a full field of view of 60&#xb0; (high quality field over) 53&#xb0;. The lens is near-telecentric to less than 6&#xb0;, apochromatic from 450 nm to 650 nm, and athermal from &#x2212;15&#xb0; C. to +40&#xb0; C. Embodiments have a focal plane diameter of 104 mm and are compatible for use with a CMOS 1.8 gigapixel multiple FPA. In some embodiments the focal length is 101 mm and the back working distance is more than 10 mm. In embodiments the lens includes three groups of optical elements, with an aperture located between the first and second groups. In some of these embodiments, the first group has at least three elements, while the second and third groups have four and three elements respectively, and the diameter of the first two groups, including housing, is less than 65 mm.

Athermal apochromatic telecentric F-theta lens with low F-number

A hyperspectral imaging system has fore-optics including primary, secondary and tertiary fore-optics mirrors, and an imaging spectrometer including primary, secondary and tertiary spectrometer mirrors. Light from a distant object is collected by the primary fore-optics mirror, and the tertiary fore-optics mirror forms an intermediate object image at an entrance side of a spectrometer slit. The spectrometer mirrors are configured so that light from an exit side of the slit is diffracted by a grating on the secondary mirror, and an image representing spectral and spatial components of the object is formed by the tertiary spectrometer mirror on a focal plane array. The surface of each mirror of the fore-optics and the spectrometer has an associated axis of symmetry. The mirrors are aligned so that their associated axes coincide to define a common system axis, thus making the imaging system easier to assemble and align in relation to prior systems.

Airborne hyperspectral imaging system

An imaging catadioptric spectrometer using a Mangin type lens and pupil lens adjacent to a grating. Electromagnetic radiation received by aperture slits is directed to a reflective portion of a Mangin type lens and redirected to a pupil adjacent a diffraction grating. Diffracted light is transmitted through a refractive portion of the Mangin type lens and through a corrector lens to image the spectral components of electromagnetic radiation onto a detector. The detector may be an enhanced detector utilizing an array of smaller spaced detectors. By balancing the powers of the lens elements, a single optical material may be used. In one embodiment, multiple aperture slits are spaced apart and decentered with respect to the optical axis permitting collection of opposing diffraction orders on two detectors. A wide field of view having a low F number is obtained with an operating wavelength range in the infrared from approximately 7.5 to 13.5 microns. The spectrometer is particularly suited to airborne applications.

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Roslyn, NY, United States of America

Michael J Russo, Jr