Low weight, achromatic, athermal, long wave infrared objective lens

• US 5,737,120 A
• Filed: 03/14/1995
• Issued: 04/07/1998
• Est. Priority Date: 03/14/1995
• Status: Expired due to Term

• Current Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Corning Incorporated
• Inventors: Arriola, Edmund W.
• Primary Examiner(s): Henry, Jon W.
• Application Number:
  US08/403,419
• Time in Patent Office: 1,120 Days
• Field of Search: 359/356, 359/357, 359/354, 359/565, 359/566, 359/571, 359/16, 359/19, 359/15
• US Class Current: 359/356
• CPC Class Codes: G02B 13/14 for use with infrared or ultraviolet radiation G02B13/008, G02B13/16 take precedence
• CPC Class Codes: G02B 5/32 Holograms used as optical elements

Abstract

A low weight, achromatic, athermal, long wave infrared objective lens with one element having a positive optical power and the other element having a negative optical power but with a higher thermo-optic coefficient than the thermo-optic coefficient of the first element. A diffractive color correcting optical surface is generated on one surface of one of the elements and aspheric surfaces may be included for further performance gains.

Claims

1. A low weight, athermal, color corrected objective lens for use in any portion of the 8 to 12 um spectral band generated by an IR source and consisting of,

a first optical lens element having positive optical power nearest the source,

a second optical lens element having negative optical power between the first optical lens element and its focal plane,

the lens material of said second optical lens element having a higher thermo-optic coefficient than the thermo-optic coefficient of the lens material of said first optical lens element and,

a diffractive surface generated on one surface of one of said lens elements for color correction so that the entire spectral band of 8 to 12 um is in focus at said focal plane.

2. The lens as claimed in claim 1 wherein said diffractive surface is a kinoform.

3. The lens as claimed in claim 2 wherein one of said optical lens elements is aspheric.

4. A low weight, athermal, achromatic, LWIR objective lens for a source generating IR in the 8-12 spectral band and consisting of,

a first optical lens element having positive optical power and positioned to receive light from the IR source first,

a second optical lens element having a negative optical power positioned to receive light from the first optical lens element,

said second optical lens element having a higher thermo-optic coefficient than the thermo-optic coefficient of said first optical lens element,

one surface of one of said optical elements being diffractive in form so that the entire spectral band of 8-12 um is in focus at the focal plane of said second optical lens element.