One optical design pattern/method of a cost effective IR lens

• US 10,641,928 B2
• Filed: 09/22/2017
• Issued: 05/05/2020
• Est. Priority Date: 09/23/2016
• Status: Active Grant

• Current Assignee: Lightwave technologies Inc.
• Original Assignee: Lightwave technologies Inc.
• Inventors: Ding, Fujian, Lifshotz, Mark
• Primary Examiner(s): Allen, Stephone B
• Assistant Examiner(s): Booher, Adam W
• Application Number:
  US15/712,991
• Publication Number:
  US 20180088257A1
• Time in Patent Office: 956 Days
• CPC Class Codes: G02B 1/00 Optical elements characterised by the material of which they are made; Optical coatings for optical elements
• CPC Class Codes: G02B 13/14 for use with infrared or ultraviolet radiation G02B13/008, G02B13/16 take precedence
• CPC Class Codes: G02B 13/16 for use in conjunction with image converters or intensifiers , or for use with projectors, e.g. objectives for projection TV
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 27/0037 with diffracting elements G02B27/0056 takes precedence; holographic optical elements G02B5/32; zone systems G02B5/1876
• CPC Class Codes: G02B 27/4216 correcting geometrical aberrations
• CPC Class Codes: G02B 3/0062 Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
• CPC Class Codes: G02B 3/04 with continuous faces that are rotationally symmetrical but deviate from a true sphere , e.g. so called "aspheric" lenses
• CPC Class Codes: G02B 5/1814 structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings G02B5/189 takes precedence
• CPC Class Codes: G02B 5/1876 Diffractive Fresnel lenses; Zone plates; Kinoforms G02B5/1842, G02B5/1847 take precedence; optical systems having diffractive correction means G02B27/0037; Fresnel lenses operating by refraction G02B3/08

Abstract

An optical design pattern/method was invented to control the total cost including the material and the manufacturing of IR imaging lenses. This optical design pattern/method comprises a molded lens and an aberration correction lens. This design pattern/method leads to cost-effective IR imaging lenses because the unit cost of the molded lens is low for a volume production and the unit cost of the aberration correction lens is low for its very small manufacturing. This optical design pattern/method comprises any imaging and spectral applications for any partial band of 1 to 14 micron, such as (but not limited to) SWIR, MWIR, and LWIR.

Claims

1. A lens system comprising:

a first lens element having a first and second surface, one of the first and second surfaces being a concave surface and the other of the first and second surfaces being a convex surface, and one of the first and second surfaces of the first lens element being a diffractive surface, the first lens element comprising chalcogenide glass, and

a second lens element having a planar surface and no diffractive surfaces, the second lens element comprising a material selected from the group consisting of Germanium, Silicon, ZnSe, ZnS, CdTe, KBr, CaF2, BaF2, MgF2, SiO2, and GaAs,

wherein the optical power of the first lens element is greater than the optical power of the second lens element, and

wherein the second lens element provides aberration correction.

2. The lens system of claim 1, wherein the focal length of the lens system is about 22.5 mm.

3. The lens system of claim 1, wherein the second lens element comprises an aspheric surface opposite the planar surface.

4. The lens system of claim 1, wherein the first lens element comprises an aspheric surface.

5. The lens system of claim 1, wherein the first lens element comprises a spherical surface.

6. An imaging system comprising the lens system of claim 1, the imaging system comprising a focal plane array (FPA), wherein the second lens element is between the first lens element and FPA, the lens system configured to direct light incident on the first lens element in a wavelength range between 1 to 14 micron on the FPA.

7. The lens system of claim 6, wherein the lens system has no other lens elements positioned between the first lens element and the second lens element.

8. The lens system of claim 7, wherein there are no other lens elements positioned between the second lens element and the FPA.

9. An imaging system comprising the lens system of claim 1, the imaging system comprising a focal plane array (FPA), wherein the first lens element is between the second lens element and FPA, the lens system configured to direct light incident on the second lens element in a wavelength range between 1 to 14 micron on the FPA.

10. The lens system of claim 9, wherein there are no other lens elements positioned between the second lens element and the FPA.

11. The lens system of claim 10, wherein there are no other lens elements positioned between the first lens element and the second lens element.

12. A lens assembly comprising:

a first lens element comprising chalcogenide glass, the first lens element having a first and second surface, one of the first and second surfaces being a concave surface and the other of the first and second surfaces being a convex surface, one of the first and second surfaces of the first lens element being a diffractive surface; and

a second lens element having a planar surface and no diffractive surfaces, the second lens element comprising a material selected from the group consisting of Germanium, Silicon, ZnSe, ZnS, CdTe, KBr, CaF2, BaF2, MgF2, SiO2, and GaAs,

wherein the optical power of the second lens element is less than the optical power of the first lens element, and

wherein the second lens element provides aberration correction.

13. The lens assembly of claim 12, wherein the second lens element comprises an aspheric surface opposite the planar surface.

14. The lens assembly of claim 12, wherein the first lens element comprises an aspheric surface.

15. The lens assembly of claim 12, wherein the first lens element comprises a spherical surface.

16. The optical system of claim 12, wherein the lens assembly has no other lens elements positioned between the first lens element and the second lens element.

17. An optical system comprising:

a molded lens having an optical power, the molded lens having a first and second surface, one of the first and second surfaces being a concave surface and the other of the first and second surfaces being a convex surface, and one of the first and second surfaces of the first lens element being a diffractive surface, the molded lens comprising chalcogenide glass, and

an aberration correction element having no diffractive surfaces, the aberration correction element comprising a material selected from the group consisting of Germanium, Silicon, ZnSe, ZnS, CdTe, KBr, CaF2, BaF2, MgF2, SiO2, and GaAs,

wherein optical power provided by the aberration correction element is less than the optical power of the molded lens, and

wherein the aberration correction element comprises a planar surface.

18. The optical system of claim 17, wherein the aberration correction element comprises an aspheric surface opposite the planar surface.

19. The optical system of claim 17, wherein the molded lens comprises an aspheric surface.

20. The optical system of claim 17, wherein the molded lens comprises a spherical surface.

21. The optical system of claim 17, wherein the optical system has no other lens elements positioned between the molded lens and the aberration correction element.