Abstract: An optical system for multispectral, infrared light having at least three element. Such systems include a first element having a first thermal glass constant-instantaneous Abbe number product and a first peak wavelength, and a second glass element having a second thermal glass constant-instantaneous Abbe number product and a second peak wavelength. The first product and the second product differing from one another by greater than 0.0075 K?1. The first peak wavelength and the second peak wavelength are greater than 6 microns. The system also includes a third glass element having a third product and a third peak wavelength, the third wavelength differing from the first wavelength and the second by at least 3 microns, the third wavelength being in the range 1-5 microns. The sum of the first, second and third products being about zero. A doublet for transmitting multispectral light is also disclosed, as well as methods of designing such lenses.

Abstract: An optical system for multispectral, infrared light having at least three element. Such systems include a first element having a first thermal glass constant-instantaneous Abbe number product and a first peak wavelength, and a second glass element having a second thermal glass constant-instantaneous Abbe number product and a second peak wavelength. The first product and the second product differing from one another by greater than 0.0075 K?1. The first peak wavelength and the second peak wavelength are greater than 6 microns. The system also includes a third glass element having a third product and a third peak wavelength, the third wavelength differing from the first wavelength and the second by at least 3 microns, the third wavelength being in the range 1-5 microns. The sum of the first, second and third products being about zero. A doublet for transmitting multispectral light is also disclosed, as well as methods of designing such lenses.

Abstract: A sight attachable to a weapon and comprising an objective lens, an image display, and a digital reticle. The objective lens focuses infrared light received from a scene onto a thermal imager, which is comprised of a focal plane array that detects infrared radiation in the scene focused by the lens. The image display is in signal communication with the thermal imager and provides an image of the received infrared light from the scene. The image rendered by the display is visible to the user. The digital reticle is rendered on the display and provides an aim point of the weapon upon a target in the scene. The image of the scene and superimposed reticle are directly viewable by a user with the aim point of the weapon upon the target being maintained constant over a range of viewing angles that depart from a viewing angle perpendicular to the display.

Abstract: A sight attachable to a weapon and comprising an objective lens, an image display, and a digital reticle. The objective lens focuses infrared light received from a scene onto a thermal imager, which is comprised of a focal plane array that detects infrared radiation in the scene focused by the lens. The image display is in signal communication with the thermal imager and provides an image of the received infrared light from the scene. The image rendered by the display is visible to the user. The digital reticle is rendered on the display and provides an aim point of the weapon upon a target in the scene. The image of the scene and superimposed reticle are directly viewable by a user with the aim point of the weapon upon the target being maintained constant over a range of viewing angles that depart from a viewing angle perpendicular to the display.

Abstract: A sight attachable to a weapon and comprising an objective lens, an image display, and a digital reticle. The objective lens focuses infrared light received from a scene onto a thermal imager, which is comprised of a focal plane array that detects infrared radiation in the scene focused by the lens. The image display is in signal communication with the thermal imager and provides an image of the received infrared light from the scene. The image rendered by the display is visible to the user. The digital reticle is rendered on the display and provides an aim point of the weapon upon a target in the scene. The image of the scene and superimposed reticle are directly viewable by a user with the aim point of the weapon upon the target being maintained constant over a range of viewing angles that depart from a viewing angle perpendicular to the display.