Mounting of optical elements for imaging in air vehicles
View Patent ↗An optical assembly comprises a mounting structure, a plurality of optical elements, and a conformal filler material. The mounting structure has a plurality of axially spaced circumferentially recessed undercuts formed into an inner surface of the mounting structure. The optical elements are axially spaced in the mounting structure. At least one of the optical elements includes an undercut in a perimeter edge surface. The undercut is aligned with one of the plurality of undercuts in the mounting structure, such that the aligned circumferential undercuts define a void. The conformal filler material is cast in place in the void to create a mechanical lock between the optical element and mounting structure.
1. An optical assembly comprising:
a mounting structure including a plurality of axially spaced circumferential recessed undercuts formed into an inner surface of the mounting structure;
a plurality of optical elements axially spaced in the mounting structure, at least one of the plurality of optical elements including an undercut in a perimeter edge surface of the optical element, the undercut in the perimeter edge aligned with one of the plurality of undercuts in the mounting structure, the aligned circumferential undercuts defining a void; and
a conformal filler material cast in place in the void to create a mechanical lock between the optical element and mounting structures;
wherein the conformal filler material, or a precursor thereof, is selected from a group consisting of: epoxy, silicone, urethane resin, solder material, braze material, frit glass, ceramic cement, and combinations thereof.
2. The optical assembly of claim 1 , wherein the mounting structure further comprises:
a plurality of ports providing communication between an outer surface of the mounting structure and at least one of the circumferential recessed undercuts.
3. The optical assembly of claim 1 , wherein the mounting structure includes a cylindrical body and a central bore defined by the inner surface.
4. The optical assembly of claim 3 , wherein a width of the central bore increases stepwise along an optical axis between the open end and the receiving end.
5. The optical assembly of claim 4 , wherein corresponding ones of the plurality of optical elements have a diameter increasing stepwise along the optical axis.
6. The optical assembly of claim 1 , further comprising:
a full-range image sensor disposed at a receiving end of the optical assembly.
7. The optical assembly of claim 6 , wherein the image sensor is connected to a wireless communication system for transmitting a sensed image to an external location.
8. The optical assembly of claim 7 , further comprising:
a plurality of spacers disposed between adjacent ones of the convex optical element and the concave optical element.
9. The optical assembly of claim 1 , wherein the plurality of optical elements including alternating ones of a convex optical element and a concave optical element.
10. A method for making an optical assembly, the method comprising:
providing a mounting structure including a plurality of axially spaced circumferential recessed undercuts formed into an inner surface of the mounting structure;
inserting a first optical element into a bore of the mounting structure, the first optical element including an undercut in a perimeter edge surface of the optical element;
aligning the undercut in the perimeter edge of the optical element with one of the plurality of undercuts in the mounting structure, the aligned circumferential undercuts defining a void; and
casting a conformal filler material in place into the void to create a mechanical lock between the optical element and mounting structures,
wherein the casting step comprises:
injecting a curable filler material into a plurality of ports providing communication between an outer surface of the mounting structure and at least one of the circumferential recessed undercuts; and
curing the filler material to form the mechanical lock;
wherein the mechanical lock is a residual compressive force between the mounting structure and the optical element independent of any adhesive bond which may exist.
11. The method of claim 10 , further comprising:
after the inserting step, inserting a plurality of axially spaced optical elements into the bore of the mounting structure, each of the plurality of axially spaced optical elements having an undercut in a perimeter edge surface.
12. The method of claim 11 , further comprising:
aligning the undercut in the perimeter edge of each of the plurality of optical elements with corresponding ones of the plurality of recessed undercuts in the inner surface of the mounting structure to define a plurality of axially spaced voids; and
casting a conformal filler material in place in each of the plurality of voids to create a mechanical lock between the optical element and mounting structure.
13. The method of claim 12 , wherein the plurality of optical elements including alternating ones of a convex optical element and a concave optical element.
14. The method of claim 12 , further comprising:
assembling a plurality of spacers between adjacent ones of the plurality of optical elements.
15. The method of claim 10 , wherein a width of a central bore increases stepwise along an optical axis between the open end and the receiving end.
16. The method of claim 15 , wherein corresponding ones of the plurality of optical elements have a diameter increasing stepwise along the optical axis.
17. The method of claim 10 , wherein the conformal filler material, or a precursor thereof, is selected from a group consisting of: epoxy, silicone, urethane resin, solder material, braze material, frit glass, ceramic cement, and combinations thereof.
18. The method of claim 10 , further comprising:
installing a full-range image sensor at a receiving end of the optical assembly.