Method Of Determining Optical Parameters Of An Ophthalmic Lens

• US 20150286069A1
• Filed: 11/13/2013
• Published: 10/08/2015
• Est. Priority Date: 11/14/2012
• Status: Active Grant

• Current Assignee: Essilor International SA (EssilorLuxottica SA)
• Original Assignee: Essilor International SA (EssilorLuxottica SA)
• Inventors: Allione, Pascal, Chauveau, Jean-Pierre, Steigelman, Daniel
• Granted Patent: US 9,671,618 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01M 11/02 Testing optical properties
• CPC Class Codes: G01M 11/025 by determining the shape of the object to be tested measuring contours or curvatures by optical means G01B11/24
• CPC Class Codes: G02C 7/027 considering wearer's parameters
• CPC Class Codes: G02C 7/028 Special mathematical design techniques
• CPC Class Codes: G02C 7/061 Spectacle lenses with progressively varying focal power

Abstract

Method for determining the values of a set of n optical parameters (P₁, P₂, . . . , P_n) of an ophthalmic lens, n being an integer greater than or equal to 1, the method comprising: an nominal ophthalmic lens data providing step, an ophthalmic lens providing step, an optical surface measuring step, a surface errors determining step during which a set of m surface error parameters (α₁, α₂, . . . , α_m) is determined, m being an integer greater than or equal to 1, an optical parameter determining step during which each optical parameter of the set of optical parameters is determined by:

$P_i=P_{i,0}+\left[\sum _{j=1}^m{\left(\frac{\partial P_i}{\partial {\alpha }_j}\right)}_0\times {\mathrm{\Delta \alpha }}_j\right]+A_i$

with P_i the value of the ith optical parameter of the manufactured optical lens, P_i,0 the value of the ith optical parameter of the nominal optical lens,

${\left(\frac{\partial P_i}{\partial {\alpha }_j}\right)}_0$

the value of the derivative of P_i with respect to the jth surface error parameter α_j on the nominal surface and Δα_j the value of the jth surface error parameter, and A_i a combination of terms of order greater or equal to 2 for each P₁.

Claims

1. A method for example implemented by computer means, for determining the values of a set of n optical parameters (P₁, P₂, . . . , P_n) of an ophthalmic lens, n being an integer greater than or equal to 1, the method comprising:

an nominal ophthalmic lens data providing step during which nominal data representing an nominal ophthalmic lens is provided;

an ophthalmic lens providing step during which an ophthalmic lens is provided, the ophthalmic lens comprising at least two optical surfaces at least one of which is manufactured based on the corresponding surface of the nominal ophthalmic lens also named “

nominal surface”

;

an optical surface measuring step during which the at least one manufactured surface of the ophthalmic lens is measured;

a surface errors determining step during which a set of m surface error parameters (α

₁, α

₂, . . . , α

_m) is determined, m being an integer greater than or equal to 1, the surface error parameters representing the differences in position and/or shape of the measured optical surface and the corresponding surface of the nominal ophthalmic lens; and

an optical parameter determining step during which each optical parameter of the set of optical parameters is determined by;

2. The method according to claim 1, wherein during the optical parameter determining step at least part, for example all, of the optical parameters are determined by having:

3. The method according to claim 1, wherein during the optical parameter determining step at least part of the optical parameters are determined by having A_i=0.

4. The method according to claim 1, wherein at least one optical parameter is determined under specific conditions defined by at least a reference point out of the ophthalmic lens and the position and orientation of the ophthalmic lens with respect to the reference point.

5. The method according to claim 1, wherein the ophthalmic lens is adapted for a wearer and at least one optical parameter is determined under given wearing conditions defined by at least a position of one of the surfaces of the ophthalmic lens with respect to a position of the center of rotation of the eye of the wearer and a pantoscopic angle and a wrap angle of the ophthalmic lens.

6. The method according to claim 5, wherein the wearing conditions are defined from measurements on the wearer and a spectacle frame chosen by the wearer.

7. The method according to claim 1, wherein at least one optical parameter is a local optical parameter, for example the at least one optical parameter is selected among the list consisting of:

spherical power, astigmatism amplitude and axis, vertical prismatic deviation, horizontal prismatic deviation, total prismatic deviation.

8. The method according to claim 1, wherein at least one optical parameter is a global optical parameter.

9. The method according to claim 1, wherein:

the nominal ophthalmic lens data represent the nominal ophthalmic lens in a nominal frame of reference, and

the measured manufactured surface of the ophthalmic lens is expressed in the nominal frame of reference.

10. The method according to claim 9, wherein the ophthalmic lens is adapted for a wearer and the nominal frame of reference is linked to the wearer.

11. The method according to claim 9, wherein during the surface errors determining step, the method further comprises:

a deformation surface providing step during which at least one deformation surface defined by at least one surface error parameter (α

_j) is provide;

a composed surface determining step during which a composed surface is determined by adding the measured manufactured surface and the at least one deformation surface; and

a surface error parameter determining step during which the values of surface error parameters (Δ

α

_j) are determined by minimizing the difference between the nominal surface and the composed surface.

12. The method according to claim 9, wherein the surface error parameters comprise at least six position parameters, for example three translation parameters (T_x, T_y, T_z) and three rotation parameters (R_x, R_y, R_z) of the at least one manufactured surface of the ophthalmic lens with respect to the nominal surface.

13. The method according to claim 9, wherein the deformation surface corresponds to a sphero-torus surface defined by a sphere parameter, a cylinder parameter and an axis parameter.

14. The method according to claim 9, wherein the deformation surface corresponds to a right circular cone defined by an axis parameter and an angle parameter.

15. A method for controlling a lens manufacturing process comprising the steps of:

a) manufacturing a master lens according to a manufacturing process using a manufacturing device;

b) determining by the method according to claim 1 at least one optical parameter of the master lens of step a);

c) recording the value of the at least one optical parameter; and

d) repeating regularly step a) to c) and checking the evolution of the at least one optical parameter over time,

wherein the evolution of at least one parameter of the manufacturing device used during the lens manufacturing process is checked over time and the evolution over time of at least one optical parameter of the master lens is related with the evolution over time of the at least one parameter of the manufacturing device.