Apparatus and Method for Making and Assembling a Multi-Lens Optical Device

Abstract

A system for aligning a plurality of high-precision lenses in a lens train. Each of the lenses has at least two alignment tabs disposed around the perimeter of the lens. The lenses are aligned by placing the lenses in a jig having a plurality of high-precision alignment blocks. The lenses are attached to a lower-precision shroud, having slots that receive the alignment tabs. A gap-filling adhesive is used to provide a high-precision fit for the lenses in the shroud.

1 . An optical device comprising:
 a lens train including a plurality of lenses, each of the plurality of lenses having a lens body and at least two lens tabs extending outwardly from the lens body;   a housing having a plurality of lens tab slots, each of the plurality of lens tab slots being configured so that the one of the plurality of lens tabs extends through the lens tab slot when the housing and plurality of lenses are fully assembled.   
     
     
         2 . The optical device of  claim 1 , wherein each of the plurality of lenses has at least one translational alignment tolerance and each of the plurality of lens tab slots is manufactured to a first dimensional tolerance, the first dimensional tolerance being larger than the at least one translational alignment tolerance. 
     
     
         3 . The optical device of  claim 1 , wherein each of at least two lens tabs is manufactured to a first dimensional tolerance and each of the plurality of lens tab slots is manufactured to a second dimensional tolerance, the second dimensional tolerance being larger than the first dimensional tolerance. 
     
     
         4 . The optical device of  claim 1 , wherein each of the plurality of lenses has a perimeter edge located between a front face and a rear face and each of the plurality of lens tabs is located along the perimeter edge. 
     
     
         5 . The optical device of  claim 1 , wherein the position of each of the plurality of lens tabs is fixed relative to a respective one of the plurality of lens slots by a gap-filing adhesive. 
     
     
         6 . An apparatus comprising:
 a lens train including a plurality of lenses and a housing in which the plurality of lenses are contained, each of the plurality of lenses having a lens body and at least two lens tabs extending outwardly from the lens body, the shape and orientation of each of the at least two tabs on each of the plurality of lenses being different than the shape and/or orientation of each of the at least two tabs on each of the other lenses of the plurality of lenses.   
     
     
         7 . The apparatus of  claim 6 , wherein each of the plurality of lenses has a perimeter edge and the at least two tabs of each of the plurality of lenses are unequally spaced around the perimeter edge. 
     
     
         8 . The apparatus of  claim 6 , wherein the at least two tabs comprises three tabs. 
     
     
         9 . A method for aligning a plurality of lenses in a lens train to form an optical device, the method comprising:
 positioning each of the plurality of lenses on an alignment jig at a first tolerance that is no less than a predetermined alignment tolerance;   affixing each of the plurality of lenses to a housing at a second tolerance that is no less than the alignment tolerance, the housing being manufactured to a tolerance that is larger than the alignment tolerance;   removing the plurality of lenses and the housing from the alignment jig;   maintaining the relative position of each of the plurality of lenses within a third tolerance that is no less than the predetermined alignment tolerance after the plurality of lenses and the housing are removed from the alignment jig.   
     
     
         10 . The method of  claim 9 , further comprising placing an upper portion of the housing into the alignment after the positioning step. 
     
     
         11 . The method of  claim 9 , wherein the affixing step further comprises using a gap filling adhesive to adhere each of the plurality of lenses to the housing. 
     
     
         12 . The method of  claim 9 , wherein the positioning step comprises inserting each of the at least two tabs located on each of the plurality of lenses into an alignment slot located in each of the alignment blocks. 
     
     
         13 . The method of  claim 12 , wherein the affixing step further comprises using a gap filling adhesive to fix the position of each of the at least two tabs in a corresponding slot formed in the housing to a tolerance that is no greater than the alignment tolerance. 
     
     
         14 . The method of  claim 12 , wherein the positioning step further comprises urging a control surface located on each of the at least two tabs of each of the plurality of lenses against a bearing surface located in the alignment slot of each of the alignment blocks. 
     
     
         15 . A method comprising:
 positioning a first lens in a first alignment block;   affixing the first lens to a housing while the lens is positioned in the first alignment block; and   after the affixing step, removing the first lens from the first alignment block with the housing attached.   
     
     
         16 . The method of  claim 15 , wherein the positioning step comprises urging a control surface located on each of a plurality of tabs located on the first lens against a bearing surface located on the alignment block. 
     
     
         17 . The method of  claim 15 , wherein the positioning step further comprises positioning a first lens in a first alignment block within a first set of alignment tolerances, the first set of alignment tolerances including a tolerance for each of three degrees of translational freedom for the first lens. 
     
     
         18 . The method of  claim 17 , further comprising maintaining the position of the first lens relative to the housing within the first set of alignment tolerances after the removing step. 
     
     
         19 . The method of  claim 18 , wherein the affixing step comprises affixing the first lens to a housing while the lens is positioned in the first alignment block, the housing being manufactured to a dimensional tolerance that is larger than any of the tolerances of the first set of alignment tolerances. 
     
     
         20 . The method of  claim 18 , wherein the positioning step further comprises positioning a second lens in a second alignment block within a second set of alignment tolerances, the second set of alignment tolerances including a tolerance for each of three degrees of translational freedom for the second lens. 
     
     
         21 . The method of  claim 20 , further comprising maintaining the position of the second lens relative to the housing within the second set of alignment tolerances after the removing step. 
     
     
         22 . A method of designing and making a first lens for use as part of an optical device having a plurality of lenses, the first lens including a lens body having at least two optical surfaces and a perimeter edge located between the at least two optical surfaces, the method comprising:
 forming at least two optical surfaces of the lens body and a perimeter edge having a first perimeter shape, the first perimeter shape being a simple closed curve;   identifying a first portion of the lens body through which light generated by the optical device could potentially pass when the optical device is operated and a second portion of the lens through which light generated by the optical device will not pass when the optical device is operated;   after the forming step, removing at least part of the second portion of the lens body, the removing step resulting in the perimeter edge having a second perimeter shape that is a complex closed curve.   
     
     
         23 . The method of  claim 22 , wherein the identifying step further comprises creating a software-based model of at least some of the optical properties of the optical device. 
     
     
         24 . The method of  claim 22 , wherein the forming step further comprises forming at least two tabs that extend from the perimeter edge. 
     
     
         25 . The method of  claim 22 , wherein the forming step comprises forming at least two optical surfaces of the lens body and a perimeter edge having a first perimeter shape, the first perimeter shape being a circle or an ellipse. 
     
     
         26 . The method of  claim 22 , wherein the forming step comprises forming the at least two optical surfaces of the lens body and the perimeter edge having a first perimeter shape using an injection molding process. 
     
     
         27 . The method of  claim 22 , wherein the removing step comprises machining at least part of the second portion of the lens body.