Anti-reflection treatment for optical elements

• US 5,763,054 A
• Filed: 09/13/1996
• Issued: 06/09/1998
• Est. Priority Date: 09/13/1996
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Lee, Paul S., Yujiri, Mikio Larry, Stark, Barry H., Samec, Thomas K.
• Primary Examiner(s): Ryan, Patrick
• Assistant Examiner(s): MULVANEY, ELIZABETH EVANS
• Application Number:
  US08/710,232
• Time in Patent Office: 634 Days
• Field of Search: 428/195, 428/196, 428/201, 428/224, 428/225, 351/44, 351/47, 351/53
• US Class Current: 428/195.1
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 1/12 by surface treatment, e.g. by irradiation
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 428/2481 including layer of mechanically interengaged strands, strand-portions or strand-like strips
• CPC Class Codes: Y10T 428/24851 Intermediate layer is discontinuous or differential
• CPC Class Codes: Y10T 442/153 Including an additional scrim layer
• CPC Class Codes: Y10T 442/183 Synthetic polymeric fiber

Abstract

An anti-reflection coating for optical elements and a method for forming an anti-reflection coating on an optical element includes one or more layers of a woven plastic mesh material that may be layered on the surface of an optical element such as the lens and secured thereto with a suitable adhesiveor pressed on to the surface by either a peripheral retaining ring or bodily pressed in place by a low loss, low dielectric medium. The number and thickness of the layers of the woven plastic mesh material are selected to provide optimal reduction of reflection losses.

Claims

1. An anti-reflection coating for use on an optical element at a predetermined electromagnetic frequency range, the anti-reflection coating comprising:

one or more layers of a predetermined woven plastic material, secured relative to said optical element, wherein the number of layers are selected to minimize the reflection of said optical element.

2. The anti-reflection coating as recited in claim 1, wherein said one or more layers are secured to said optical element with a predetermined adhesive, transparent to said predetermined electromagnetic frequency range.

3. The anti-reflection coating recited in claim 1, wherein said anti-reflection coating is formed from a plurality of layers having the same mesh size.

4. The anti-reflection coating as recited in claim 1, wherein said anti-reflection coating is formed from a plurality of layers having different mesh sizes.

5. The anti-reflection coating as recited in claim 1, wherein said various predetermined optical elements include a predetermined lens.

6. The anti-reflection coating as recited in claim 5, wherein said predetermined lens is convex.

7. The anti-reflection coating as recited in claim 5, wherein said predetermined lens is concave.

8. The anti-reflection coating as recited in claim 1, wherein said anti-reflection coating is formed from a plurality of layers.

9. The anti-reflection coating as recited in claim 1, wherein said plurality of layers have the same thickness.

10. The anti-reflection coating as recited in claim 1, wherein said plurality of layers have at least two (2) different thicknesses.

11. A method for forming an anti-reflection coating for an optical element comprising the steps of:

(a) securing one or more layers of a woven plastic material to a surface of said optical element;

(b) determining the number and thickness of said layers of said woven plastic material by measuring the reduction in reflection losses.

12. In combination with a millimeter wave imaging system which includes one or more lenses, an anti-reflection coating for said one or more lenses, the anti-reflection coating comprising:

one or more layers of a predetermined woven plastic material, secured to at least one of said one or more lenses, the number of layers being selected to minimize reflections of said lens.

13. The system recited in claim 12 further including a predetermined material, transparent to microwaves, for pressing said one or more layers against said lens for securing said one or more layers to said at least one of said one or more lenses.

14. The system recited in claim 13, wherein said predetermined material is selected to provide thermal protection to said primary lens.

15. The system as recited in claim 14, wherein in said predetermined material is styrofoam.

16. The system as recited in claim 12, further including an adhesive for securing one or more layers of said predetermined woven plastic material to at least one of said one or more lenses.

17. The system as recited in claim 12, further including a means for clamping one or more layers of said predetermined woven plastic material to at least one of said one or more lenses.