Toric axis alignment machine and method
AssigneeBausch & Lomb Incorporated
InventorsWilliam John Appleton, Kevin Jacob DeRyke, Michael Henry Dobner, Allen Lee Ormiston, Ian Andrew Powell, Jeffrey Michael Vandewinckel
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Abstract
A method and apparatus for practicing the method of making toric contact lenses having a toric axis and ballast axis located on the anterior and posterior surfaces of a lens. Detectable features are formed on the anterior and posterior mold sections corresponding to the location of the toric axis and ballast axis, respectively. An axis alignment tool having detecting means thereon is used to set the mold sections to a known angular position. The desired axial offset is input into a computer which establishes the axial offset between the mold sections.
Claims18
A method for molding toric contact lenses having opposite anterior and posterior optical surfaces, said toric lenses further including a toric axis and a ballast axis formed on said opposite optical surfaces thereof, respectively, including automatically and selectively establishing any one of a plurality of predetermined axial offsets, between 0 degrees and 180 degrees, between said toric axis and said ballast axis of said lenses, said method comprising the steps of:
- a) providing anterior and posterior mold sections having anterior and posterior mold surfaces, respectively, said toric axis formed on one of said anterior and posterior molding surfaces, and said ballast axis formed on the other of said anterior and posterior mold surfaces, said anterior and posterior mold surfaces forming said anterior and posterior optical surfaces of said lenses, respectively;
- b) providing a detectable feature on each of said anterior and posterior mold sections at a predetermined angular location with respect to said toric and ballast axes thereof, respectively;
- c) providing a toric axis alignment tool having bottom and top sections and including means for detecting and locating said detectable features on each of said anterior and posterior mold sections at known angular positions upon engaging said anterior and posterior mold sections with said bottom and top sections of said axis alignment tool, respectively, and simultaneously rotating said anterior and posterior mold sections relative to said toric axis alignment tool;
- d) releasing said anterior and posterior mold sections from said axis alignment tool while maintaining said known angular positions of said anterior and posterior mold sections;
- e) rotating at least one of said anterior and posterior mold sections to establish said predetermined axial offset between said toric axis and said ballast axis;
- f) charging said anterior mold section with a predetermined quantity of liquid lens material;
- g) capping said posterior mold section on said anterior mold section with a predetermined clamping pressure, thereby forming a mold chamber between said anterior and posterior mold surfaces;
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- h) curing said liquid lens material in said mold chamber, thereby forming said toric lens having said toric and ballast axes formed on said opposite optical surfaces thereof at said predetermined axial offset.
Apparatus for automatically molding toric contact lenses having opposite anterior and posterior optical surfaces with one of said optical surfaces having a toric axis and the other of said optical surfaces having a ballast axis, said apparatus comprising:
- a) an anterior mold section having an anterior mold surface for molding said anterior optical surface of said lenses, said anterior mold section having a detectable feature positioned at a predetermined location on said anterior mold section relative to said one of said toric axis and ballast axis thereof;
- b) a posterior mold section having a posterior mold surface for molding said posterior optical face of said lens, said posterior mold section having a detectable feature positioned at a predetermined location on said posterior mold relative to said one of said ballast axis and toric axis thereof;
- c) means for detecting and positioning said detectable features of each of said anterior and posterior mold sections at a predetermined angular location with respect to each other, said means comprising an axis alignment tool having top and bottom sections each having a said detecting means, and wherein said posterior mold section is engagable with and rotatable with respect to said top section thereof, and said anterior mold section is engagable with and rotatable with respect to said bottom section thereof whereby said axis alignment tool is operable to simultaneously position said posterior and anterior mold sections at said predetermined angular locations;
- d) input means for selecting a predetermined angular offset between said ballast axis and said toric axis of said anterior and posterior mold sections through at least one production run of said toric lenses, said predetermined angular offset capable of being selectively changed between production runs;
- e) means for rotating at least one of said anterior and posterior mold sections, in response to a signal received from said input means, until said ballast axis and said toric axis of said anterior and posterior mold sections are at said predetermined angular offset;
- f) means for depositing a measured quantity of liquid lens material into said anterior mold surface;
- g) means for capping said posterior and anterior mold sections together to form a mold cavity wherein said liquid mold material is located;
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- h) means for curing said liquid lens material into a said toric lens.
Dependencies are inferred from the claim text.