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 optic for a head mounted display having a first concave surface, a convex surface, and a second concave surface. The first concave surface receives light incident to its surface and transmits the light. The convex surface reflects light. The second concave surface reflects the light transmitted by the first concave surface and transmits the light reflected by the convex surface so that the light reflected by the convex surface travels through the second concave surface and is emitted outwardly.

Abstract: An optic for a head mounted display having a first concave surface, a convex surface, and a second concave surface. The first concave surface receives light incident to its surface and transmits the light. The convex surface reflects light. The second concave surface reflects the light transmitted by the first concave surface and transmits the light reflected by the convex surface so that the light reflected by the convex surface travels through the second concave surface and is emitted outwardly.

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.