Method and apparatus for determining surface data and/or measurement data relating to a surface of an at least partially transparent object

Patent metadata

Field	Value
Publication number	US-10337953-B2
Application number	US-201615555300-A
Country	US
Kind code	B2
Filing date	Mar 23, 2016
Priority date	Jun 3, 2015
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

A method and an apparatus for determining surface data and/or measurement data relating to a surface, for the quality control of an at least a partially transparent object, an ophthalmic lens, having an optically active first surface and an opposite optically active second surface. The method includes irradiating polarized light with an irradiation polarization from at least one illumination device onto an analysis area of the object to be examined, wherein, for the purpose of setting the irradiation polarization, the light is passed through a polarizer assigned to the illumination device or integrated in the latter, and receiving light which is reflected at the first and/or second surface and has an analysis polarization by use of at least one receiving device, wherein the light is passed through an analyzer assigned to the receiving device or integrated in the latter.

First claim

The invention claimed is:

1. A method for determining data relating to a surface having an optically active first surface and an opposite optically active second surface, comprising:
irradiating polarized light with an irradiation polarization from at least one illumination device onto an analysis area of the object to be examined, wherein, for the purpose of setting the irradiation polarization, the light is passed through a polarizer assigned to the illumination device or integrated in the illumination device,
receiving light that is reflected at the first or second surface and has an analysis polarization by at least one receiving device, wherein the light is passed through an analyzer assigned to the receiving device or integrated in the receiving device,
at least partially suppressing an undesirable light intensity reflected by the first or second surface and received by the receiving device through setting of the irradiation polarization of the polarizer or the analysis polarization of the analyzer,
measuring an intensity distribution or a wavefront of the light received with the analysis polarization, in order to determine data relating to the surface in the analysis area.

2. The method according to claim 1 , wherein, in the analysis area, a deviation of the data relating to the surface from a target data is determined.

3. The method according to claim 1 , wherein the irradiation polarization and/or the analysis polarization is selected such that, in the measured intensity distribution, the undesirable light intensity corresponds to the light received by the receiving device that is polarized differently to the analysis polarization, or a desirable light intensity corresponds to the light received by the receiving device that is polarized in a same way as the analysis polarization, wherein a detected proportion of the desirable light intensity is greater than the detected proportion of the undesirable light intensity.

4. The method according to claim 1 , wherein the irradiation polarization is polarized perpendicular or parallel to a plane of incidence that is spanned by the light irradiated on the object and the light received by the receiving device.

5. The method according to claim 1 , wherein the irradiation polarization and the analysis polarization are differently orientated to one another.

6. The method according to claim 1 , wherein the at least one illumination device comprises a plurality of illumination devices, and
wherein the plurality of illumination devices are used in parallel.

7. The method according to claim 1 , wherein the irradiated light irradiates discrete pattern elements onto the first and second surface of the object and wherein determining of the data relating to the surface in the analysis area of one of the two surfaces of the object from the measured intensity distribution comprises:
detecting a position of at least one reflected pattern element in the intensity distribution received by the receiving device,
assigning the reflected pattern element to the surface on which the reflection takes place,
using the position of the pattern element on the illumination device and the position of the reflected pattern element in the measured intensity distribution in order to determine the data relating to the surface.

8. The method according to claim 7 , wherein, during assigning of the at least one pattern element to the surface on which the reflection takes place, the light intensity of the respective reflected pattern element is compared with a threshold value that is specified or determined from the intensity distribution.

9. The method according to claim 7 , wherein during assigning of the at least one pattern element to the surface on which the reflection takes place, the polarization of the respective reflected pattern element is at least approximately determined on the basis of the measured intensity distribution.

10. The method according to claim 1 , wherein the irradiated light irradiates planar patterns onto the first and second surface of the object and wherein the determining of the data relating to the surface in the analysis area of one of the two surfaces of the object from the measured intensity distribution comprises
determining the light intensity that is created by reflection at the at least one surface and received by the receiving device, for at least one point in the measured intensity distribution,
assigning the point to the position on the illumination device from which the light originates, which is mapped by reflection at the surface into the point of the measured intensity distribution,
using the position of the point in the measured intensity distribution and the assigned position on the illumination device in order to determine the data relating to the surface.

11. The method according to claim 10 , wherein during assigning of the position of the at least one point on the illumination device, the polarization of each reflected point is at least approximately determined on the basis of the measured intensity distribution.

12. The method according to claim 1 , wherein for an at least partial suppression or enhancement of the light reflected at the first surface the analysis polarization is mathematically determined, comprising:
breaking down the irradiated polarized light into perpendicular and parallel polarized components in a plane of incidence, multiplying the light intensity of both components by a respective reflection coefficient resulting from an angle of incidence and a refractive index of a material of the object,
combining the components of the reflected light,
determining the polarization direction of the reflected light,
setting the analysis polarization of the analyzer at least approximately perpendicular, or at least approximately parallel, to the polarization direction of the reflected light.

13. The method according to claim 1 , wherein for an at least partial suppression or enhancement of the light reflected at the second surface the analysis polarization is mathematically determined, comprising:
breaking down the irradiated polarized light into perpendicular and parallel polarized components in a first plane of incidence of the light on the first surface,
multiplying the light intensity of both components by respective transmission coefficients resulting from a first angle of incidence and a refractive index of the material of the object,
converting said components into perpendicular and parallel polarized components in a second plane of incidence of the reflection at the second surface,
multiplying the light intensity of both components by reflection coefficients resulting from a second angle of incidence and the refractive index of the material of the object and/or of a holder,
converting these components into perpendicular and parallel polarized components in a third plane of incidence of the second refraction at the first surface,

multiplying the light intensity of both components by respective second transmission coefficients resulting from a third angle of incidence and the refractive index of the material of the object,
combining the components of the transmitted light obtained in this way,
determining a polarization direction of the light refracted for a second time at the first surface,
setting the analysis polarization of the analyzer at least approximately perpendicular, or at least approximately parallel, to the polarization direction of the light diffracted for the second time by the first surface.

14. The method according to claim 1 , wherein for an at least partial suppression of the light intensity of the light reflected at

Assignees

• Rodenstock Gmbh

Inventors

• Trumm Stephan
• Sessner Rainer
• Uttenweiler Dietmar

Classifications

• G01N21/21

  Polarisation-affecting properties (G01N21/19 takes precedence) · CPC title

• G01M11/0264

  by using targets or reference patterns · CPC title

• G01M11/025

  by determining the shape of the object to be tested (measuring contours or curvatures by optical means G01B11/24) · CPC title

• G01M11/0207 Primary

  Details of measuring devices · CPC title