US2013169851(A1) has been published on 2013-07-04. The application was filed 2013-12-19 and has foreign priority data JP2011-288116. The foreign priority date is 2012-12-28, hence the US patent can make use of the this date. We will likely see a Japanese publication within a week or two since the 18 month KOKAI publication date was due 2013-06-28.
The patent deals with the problems of designing gausian or modified gausian type lenses that:
- are relatively wide in a standard context
- are compact (short total lenght) even with a BF of 38mm
- are well aberration corrected, in particular sperical and curvature of field
There are 4 numerical examples given all 1/f2.8 and image height 21.64mm (EF lens)
1) F = 45mm, L = 58mm, BF = 38mm, Effective lenght = 20mm
2) F = 39mm, L = 62.5mm, BF = 39mm, Effective lenght = 23.5mm
3) F = 35mm, L = 63mm, BF = 38mm, Effective lenght = 25mm
4) F = 28mm, L = 65mm, BF = 38mm, Effective lenght = 27mm
Layout and curves for Sperical Aberration, Astigmatism, Distortion and Chromatic Aberration can be found in the patent : http://www.freepatentsonline.com/20130169851.pdf
The patent deals with the problems of designing gausian or modified gausian type lenses that:
- are relatively wide in a standard context
- are compact (short total lenght) even with a BF of 38mm
- are well aberration corrected, in particular sperical and curvature of field
There are 4 numerical examples given all 1/f2.8 and image height 21.64mm (EF lens)
1) F = 45mm, L = 58mm, BF = 38mm, Effective lenght = 20mm
2) F = 39mm, L = 62.5mm, BF = 39mm, Effective lenght = 23.5mm
3) F = 35mm, L = 63mm, BF = 38mm, Effective lenght = 25mm
4) F = 28mm, L = 65mm, BF = 38mm, Effective lenght = 27mm
Layout and curves for Sperical Aberration, Astigmatism, Distortion and Chromatic Aberration can be found in the patent : http://www.freepatentsonline.com/20130169851.pdf
