Composite polymeric reflectors

• US 6,254,243 B1
• Filed: 09/11/2000
• Issued: 07/03/2001
• Est. Priority Date: 10/12/1999
• Status: Expired due to Fees

• Current Assignee: Walter A. Scrivens
• Original Assignee: Walter A. Scrivens
• Inventors: Scrivens, Walter A.
• Primary Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US09/658,350
• Time in Patent Office: 295 Days
• Field of Search: 359/883, 359/884, 156/163, 156/245, 156/229, 156/196, 156/280, 156/297, 156/160, 156/242, 428/429, 428/446, 428/447, 428/428, 428/432, 428/433, 428/434, 264/1.9, 264/1.7, 264/2.3, 264/2.4, 264/2.6, 264/255
• US Class Current: 359/883
• CPC Class Codes: G02B 5/10 with curved faces
• CPC Class Codes: G02B 7/183 specially adapted for very large mirrors, e.g. for astronomy, or solar concentrators

Abstract

A method for making polymeric reflectors and parabolic reflectors in particular. The reflector is made by forming a series of layers (12, 14, 16, 18, and 20) that are progressively thinner with the final polymeric layer (20) being about one millimeter in thickness. The reflector is then coated with a reflective layer (22) by vapor deposition. To make a parabolic reflector, the layers are spun cast at a constant, preselected rate throughout the process, including during the curing of each layer. Layer formation is made in a controlled, particulate-free environment and additives can be used to increase stiffness, decrease weight, and reduce stresses during curing.

Claims

1. A method of manufacturing a reflector, said method comprising the steps of:

(a) introducing an initial layer into a container having a floor;

(b) curing said initial layer;

(c) introducing an intermediate layer onto said initial layer, wherein said intermediate layer is thinner than said initial layer;

(d) curing said intermediate layer;

(e) introducing a final layer onto said intermediate layer, wherein said final layer is thinner than said intermediate layer; and

(f) curing said final layer.

2. The method of manufacturing a reflector, as recited in claim 1, wherein said initial layer, said intermediate layer and said final layer each have a glass transition range, and

wherein Step (b) is performed by curing said initial layer to a solid state while heating at a temperature within the glass transition range of said initial layer,

wherein Step (d) is performed by curing said intermediate layer to a solid state while heating at a temperature within the glass transition range of said intermediate layer, and

wherein Step (f) is performed by curing said final layer to a solid state while heating at a temperature within the glass transition range of said final layer.

3. The method of manufacturing a reflector, as recited in claim 2,

wherein Step (d) is performed by curing said intermediate layer to a solid state while heating at a temperature within the glass transition range of said intermediate layer, but not greater than the glass transition point of said initial layer, and

wherein Step (f) is performed by curing said final layer to a solid state while heating at a temperature within the glass transition range of said final layer, but not greater than the glass transition point of said intermediate layer.

4. The method as recited in claim 1, wherein said container is rotated along an axis through said floor of said container during Step (b), Step (d), and Step (f).

5. The method as recited in claim 4, wherein said container is under the influence of a constant force parallel to said axis of rotation.

6. The method as recited in claim 1, further comprising the step of:

(g) applying a reflective coating to said final layer

7. The method as recited in claim 1, further comprising the step of:

(h) adding a filler to said initial layer before curing said initial layer, said filler selected from the group consisting of glass microbeads, glass fibers, graphite fibers, boron fibers, polyester fibers, polyamide fibers, polyethylene fibers, polypropylene fibers, polystyrene fibers, poly-paraphenylene terephthalamide fibers, poly-metaphenylene diamine fibers, polytetrafluoroethylene fibers, and high-modulus polyethylene fibers.