Title:
LENS EXAMINATION EQUIPMENT AND METHOD
Document Type and Number:
WIPO Patent Application WO/2018/073577
Kind Code:
A3
Abstract:
A test pattern (170) comprising a set of dots (174) which define a first ellipse (176) of best fit in which the major and minor axes R1, R2 are equal (i.e. a circle) is displayed on a plane surface and a digital image of the (usually distorted) test pattern seen through a lens is captured. A second ellipse of best fit joining the dots in the set is derived from the distorted test pattern in the image. Characteristics of the first and second ellipses are compared to determine the degree and nature of distortion to the test pattern, from which the power of the lens is calculated. The major and minor axes of the first and second ellipses may be compared. The test pattern can include a number of said sets of dots distributed over an area of the surface with each set being analysed to determine the optical parameters of the lens at multiple locations.
Inventors:
DREW THOMAS (GB)
KRAWCZYNSKI MICHAL (GB)
JOSHI OMKAR (GB)
DAVIES JOSEPH (GB)
SUDERA SURAJ (GB)
DEAN JONATHAN (GB)
KRAWCZYNSKI MICHAL (GB)
JOSHI OMKAR (GB)
DAVIES JOSEPH (GB)
SUDERA SURAJ (GB)
DEAN JONATHAN (GB)
Application Number:
PCT/GB2017/053136
Publication Date:
July 12, 2018
Filing Date:
October 17, 2017
Export Citation:
Assignee:
ASTON EYETECH LTD (GB)
International Classes:
G01M11/02
Domestic Patent References:
| WO2016141333A1 | 2016-09-09 |
Foreign References:
| EP1679499A2 | 2006-07-12 | |||
| US20070115353A1 | 2007-05-24 |
Attorney, Agent or Firm:
WILSON GUNN (BIRMINGHAM) (GB)
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