Infrared transmissive dome systems and methods

• US 9,001,212 B2
• Filed: 03/11/2010
• Issued: 04/07/2015
• Est. Priority Date: 03/11/2010
• Status: Active Grant

• Current Assignee: Teledyne FLIR LLC (Teledyne Technologies Incorporated)
• Original Assignee: FLIR Systems, Inc. (Teledyne Technologies Incorporated)
• Inventors: Hoelter, Theodore R., Sharp, Barbara, Burt, Warn, Pietsch, Robert, Tremblay, Marcel
• Primary Examiner(s): KELLY, RAFFERTY D
• Application Number:
  US12/721,921
• Publication Number:
  US 20110221908A1
• Time in Patent Office: 1,853 Days
• Field of Search: 348/164, 359/350, 359/359, 264/1.1, 250/330
• US Class Current: 348/164
• CPC Class Codes: B29C 2043/3615 Forming elements, e.g. mandrels or rams or stampers or pistons or plungers or punching devices
• CPC Class Codes: B29C 43/021 characterised by the shape of the surface
• CPC Class Codes: B29C 43/36 Moulds for making articles of definite length, i.e. discrete articles
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/046 Materials; Selection of thermal materials
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0806 Focusing or collimating elements, e.g. lenses or concave mirrors
• CPC Class Codes: G01J 5/0875 Windows; Arrangements for fastening thereof

Abstract

Systems and methods are disclosed that provide an infrared-transmissive dome, such as for infrared imaging applications. For example, an infrared-transmissive dome, for an embodiment, includes a main body providing a hollow, hemispherical-shaped dome; wherein the main body is made of an ultra-high molecular weight or a very-high molecular weight polyethylene material; and wherein the main body has a wall thickness equal to or less than approximately 0.012 inches to allow infrared transmittance greater than approximately sixty five percent through the main body for infrared imaging in a wavelength range of approximately three to fourteen micrometers.

Claims

1. An infrared-transmissive dome, comprising:

a main body providing a hollow, hemispherical-shaped dome;

wherein the main body is made of an ultra-high molecular weight or a very-high molecular weight polyethylene material; and

wherein the main body is self-supporting and has a wall thickness equal to or less than 0.012 inches and is configured to allow infrared transmittance greater than approximately sixty five percent through the main body for infrared imaging in a wavelength range of approximately three to fourteen micrometers.

2. The infrared-transmissive dome of claim 1, wherein a ratio of the wall thickness to a diameter of the infrared-transmissive dome is approximately 0.004 or less and the wall thickness is equal to or greater than approximately 0.005 inches.

3. The infrared-transmissive dome of claim 1, wherein a peak-to-peak variation of the wall thickness is approximately 0.0001 inches or less over any contiguous area defined by a pi/16 solid angle, a variation of the wall thickness is approximately 0.001 inches or less for the main body, and a radius of curvature of the main body varies by approximately ten percent or less from a mean radius of curvature over any contiguous area defined by a pi/16 solid angle.

4. The infrared-transmissive dome of claim 1, comprising:

a flange formed as part of and along an edge of the main body;

wherein the flange is made of the ultra-high molecular weight or very-high molecular weight polyethylene material; and

wherein the flange has a wall thickness greater than 0.010 inches.

5. The infrared-transmissive dome of claim 4, wherein the flange comprises a metal ring enclosed at least partially within the ultra-high molecular weight or very-high molecular weight polyethylene material.

6. The infrared-transmissive dome of claim 4, wherein the flange comprises a stepped portion or a curved-shaped portion to mate with a corresponding portion of an enclosure for an infrared detector.

7. The infrared-transmissive dome of claim 1, wherein the main body is made of the ultra-high molecular weight polyethylene material and the very-high molecular weight polyethylene material.

8. The infrared-transmissive dome of claim 1, wherein the ultra-high molecular weight polyethylene material and/or the very-high molecular weight polyethylene material includes an additive to provide ultraviolet protection.

9. The infrared-transmissive dome of claim 8, wherein the additive includes a zinc sulfide, a titanium dioxide, a zinc oxide, an oligomeric-hindered amine-light stabilizer, and/or a hindered amine light stabilizer.

10. The infrared-transmissive dome of claim 1, comprising a thin sheet of the ultra-high molecular weight or very-high molecular weight polyethylene material layered over the main body, wherein the thin sheet has a wall thickness equal to or less than the wall thickness of the main body and includes an additive to provide ultraviolet protection and/or translucence to visible wavelengths, and wherein the infrared-transmissive dome provides greater than approximately sixty five percent transmission to infrared wavelengths within approximately eight to thirteen micrometers.

11. The infrared-transmissive dome of claim 1, wherein the ultra-high molecular weight or very-high molecular weight polyethylene material includes an additive such that the infrared-transmissive dome is generally translucent to visible wavelengths and provides greater than approximately sixty five percent transmission to infrared wavelengths within approximately eight to thirteen micrometers.

12. The infrared-transmissive dome of claim 11, wherein the additive includes a silicon material.

13. The infrared-transmissive dome of claim 1, wherein the infrared-transmissive dome is part of an infrared camera system having an infrared detector within a housing, and wherein the infrared-transmissive dome is coupled to the housing to allow infrared energy external to the housing to pass through to the infrared detector.

14. A compression mold for the infrared-transmissive dome of claim 1, the compression mold comprising:

a first mold portion having a convex portion; and

a second mold portion having a concave portion corresponding to the convex portion of the first mold portion;

wherein the convex portion disposed within the concave portion is configured to provide an approximately 0.012 gap or less between the convex portion and the concave portion such that the ultra-high molecular weight or the very-high molecular weight polyethylene material disposed between the convex portion and the concave portion, under an elevated temperature and with a compressive force applied to the compression mold, forms the infrared-transmissive dome that is self-supporting and having the wall thickness equal to or less than approximately 0.012 inches.

15. The compression mold of claim 14, wherein a surface finish of the convex portion and the concave portion are polished to between approximately 8L and 4L.

16. The compression mold of claim 14, wherein the convex portion and the concave portion are shaped such that a ratio of the wall thickness to a diameter of the infrared-transmissive dome is approximately 0.004 or less.

17. The compression mold of claim 14, wherein the convex portion and the concave portion are shaped such that a peak-to-peak variation of the wall thickness is approximately 0.0001 inches or less over any contiguous area defined by a pi/16 solid angle, a variation of the wall thickness is approximately 0.001 inches or less for the main body, and a radius of curvature of the main body varies by approximately ten percent or less from a mean radius of curvature over any contiguous area defined by a pi/16 solid angle.

18. A method of forming the infrared-transmissive dome of claim 1, the method comprising:

providing the ultra-high molecular weight or the very-high molecular weight polyethylene material within a compression mold to form the infrared-transmissive dome;

increasing a temperature of the compression mold;

applying pressure to the ultra-high molecular weight or very-high molecular weight polyethylene material via the compression mold;

decreasing the temperature of the compression mold; and

removing the ultra-high molecular weight or very-high molecular weight polyethylene material from the compression mold, wherein the ultra-high molecular weight or very-high molecular weight polyethylene material has been formed to provide the hollow, hemispherical-shaped dome having the main body that is self-supporting and with the wall thickness equal to or less than approximately 0.012 inches.

19. The method of claim 18, comprising:

inspecting the main body;

adding an additional amount of the ultra-high molecular weight or very-high molecular weight polyethylene material to certain areas of the main body that have undesired properties; and

repeating the increasing, the applying, and the decreasing operations followed by the removing of the infrared-transmissive dome from the compression mold formed from the ultra-high molecular weight or very-high molecular weight polyethylene material.

20. The method of claim 18, wherein the providing ultra-high molecular weight or very-high molecular weight polyethylene material within the compression mold is performed by a powder coat process.

21. The method of claim 18, wherein a ratio of the wall thickness to a diameter of the infrared-transmissive dome is approximately 0.004 or less, the wall thickness is equal to or greater than approximately 0.005 inches, and the infrared-transmissive dome is configured to allow infrared transmittance greater than approximately sixty five percent through the main body for infrared imaging in the wavelength range of approximately three to fourteen micrometers.

22. The method of claim 18, wherein a peak-to-peak variation of the wall thickness is approximately 0.0001 inches or less over any contiguous area defined by a pi/16 solid angle, a variation of the wall thickness is approximately 0.001 inches or less for the main body, and a radius of curvature of the main body varies by approximately ten percent or less from a mean radius of curvature over any contiguous area defined by a pi/16 solid angle.

23. The method of claim 18, wherein the ultra-high molecular weight or very-high molecular weight polyethylene material has been formed to provide a flange along an edge of the main body and having a flange wall thickness greater than 0.010 inches.

24. The method of claim 23, comprising providing a metal ring within the compression mold, wherein the metal ring is formed as part of the flange.

25. The method of claim 24, wherein the flange comprises a stepped portion or a curved-shaped portion to mate with a corresponding portion of an enclosure for an infrared detector.

26. The method of claim 18, wherein the main body is made of the ultra-high molecular weight polyethylene material and the very-high molecular weight polyethylene material.

27. The method of claim 18, wherein the ultra-high molecular weight or very-high molecular weight polyethylene material includes an additive to provide ultraviolet protection.

28. The method of claim 18, wherein the ultra-high molecular weight or very-high molecular weight polyethylene material comprises a powder or a sheet of the ultra-high molecular weight or very-high molecular weight polyethylene material.

29. The method of claim 18, comprising applying a superhydrophobic coating on the hollow, hemispherical-shaped dome.

30. The method of claim 18, wherein the ultra-high molecular weight or very-high molecular weight polyethylene material provided within the compression mold includes cutouts around an edge of the ultra-high molecular weight or very-high molecular weight polyethylene material.

31. The method of claim 18, comprising treating the compression mold with a mold surface treatment to provide a low-friction mold surface.

32. The method of claim 18, comprising disposing over the main body an additional thin sheet of the ultra-high molecular weight or very-high molecular weight polyethylene material, wherein the thin sheet has a wall thickness equal to or less than the wall thickness of the main body and includes an additive to provide ultraviolet protection and/or translucence to visible wavelengths, wherein the infrared-transmissive dome provides greater than approximately sixty five percent transmission to infrared wavelengths within approximately eight to thirteen micrometers.

33. The method of claim 18, wherein the ultra-high molecular weight or very-high molecular weight polyethylene material includes an additive such that the infrared-transmissive dome is generally translucent to visible wavelengths and provides greater than approximately sixty five percent transmission to infrared wavelengths within approximately eight to thirteen micrometers.

34. The method of claim 33, wherein the additive includes a silicon material.