Optical Assembly for a Compact Wide Field of View Digital Camera with Low First Lens Diameter to Image Diagonal Ratio
An optical assembly for a point action camera or other compact digital camera having a wide field of view, includes multiple lens elements, including at least one lens element that has an aspheric lens surface. The optical assembly is configured to provide a field of view in excess of 120 degrees. The optical assembly includes a ratio of a diameter of a first lens element at the object end of the optical assembly to an image diagonal is less than approximately 3.
1 . (canceled)
2 . A lens element comprising an aspheric surface that is configured to correct higher order astigmatism in an optical assembly configured for a point action camera having a wide field of view in excess of 120 degrees, wherein said aspheric surface comprises an aspheric sag less than approximately 12 microns.
3 . The lens element of claim 2 , wherein said aspheric surface includes a point of inflection of maximum sag at less than approximately 0.8×.
4 . The lens element of claim 2 , wherein said aspheric surface includes a point of inflection of maximum sag at less than approximately 0.75×.
5 . The lens element of claim 2 , wherein said aspheric surface includes a point of inflection of maximum sag at less than approximately 0.7×.
6 . The lens element of claim 2 , wherein said aspheric surface comprises an aspheric sag slope less than approximately 15 microns per millimeter.
7 . The lens element of claim 6 , wherein said aspheric surface includes a point of inflection of aspheric slope extremum at less than approximately 0.5×.
8 . The lens element of claim 6 , wherein said aspheric surface includes a point of inflection of aspheric slope extremum at less than approximately 0.4×.
9 . The lens element of claim 6 , wherein said aspheric surface includes a point of inflection of aspheric slope extremum at less than approximately 0.3×.
10 . The lens element of claim 2 , comprising a single aspheric lens surface, which is the only aspheric lens surface within the optical assembly, wherein lens surfaces other than said aspheric lens surface comprise spherical or planar lens surfaces, or both, each without significant aspheric departure.
11 . The lens element of claim 2 , comprising only one aspheric lens surface.
12 . A lens element comprising an aspheric surface that is configured to correct higher order astigmatism in an optical assembly configured for a point action camera having a wide field of view in excess of 120 degrees, wherein said aspheric surface comprises an aspheric sag slope less than approximately 15 microns per millimeter.
13 . The lens element of claim 12 , wherein said first surface includes a point of inflection of aspheric slope extremum at less than approximately 0.5×.
14 . The lens element of claim 12 , wherein said first surface includes a point of inflection of aspheric slope extremum at less than approximately 0.4×.
15 . The lens element of claim 12 , wherein said first surface includes a point of inflection of aspheric slope extremum at less than approximately 0.3×.
16 . The lens element of claim 12 , comprising a single aspheric lens surface, which is the only aspheric lens surface within the optical assembly, wherein lens surfaces other than said aspheric lens surface comprise spherical or planar lens surfaces, or both, each without significant aspheric departure.
17 . The lens element of claim 12 , comprising only one aspheric lens surface.