Method for determining the shape of the bevel of an ophthalmic lens

1. A method for determining the shape of the bevel of an ophthalmic lens so as to have the ophthalmic lens fit a given spectacle frame, the method comprising the steps of:

providing the three-dimensional (xi, yi, zi) internal profile of the groove of at least a rim of the spectacle frame expressed in the principal axes (Xf, Yf, Zf) of the spectacle frame and the length Pf of the periphery of the groove of the rim;

providing the blocking point of the ophthalmic lens and the horizontal direction Xl of the ophthalmic lens;

aligning the normal Zl to the surface of the ophthalmic lens at the blocking point with the Zf axe of the rim;

aligning the horizontal direction Xl of the ophthalmic lens with the Xf axe of the rim;

projecting the three-dimensional (xi, yi, zi) internal profile of the groove of the rim on the front face surface of the ophthalmic lens so as to obtain a three-dimension projected groove shape (xp, yp, zp); and

modifying the coordinates of each point of the two-dimensional groove shape (xp, yp) based on two correction coefficients, Rx for the coordinate xp and Ry for the coordinate yp, with Rx+Ry=1 so as to have the length Pp of the three-dimensional groove projected shape (xp, yp, zp) equal to the length Pf of the periphery of the internal profile of the groove of the rim so as to obtain the shape of the bevel of the ophthalmic lens.

2. The method according to claim 1 , wherein the correction coefficient RX is different than the correction coefficient RY.

3. The method according to claim 1 , wherein the spectacle frame is a closed rim spectacle frame.

4. The method according to claim 1 , wherein the spectacle frame is a semi-rimless spectacle frame.

5. An ophthalmic lens cutting method comprising the steps of:

receiving a ophthalmic lens,

receiving the three-dimensional (xi, yi, zi) internal profile the groove of at least one rim of the spectacle frame expressed in the principal axes of inertia (Xf, Yf, Zf) of the at least one rim and the length Pf of the periphery of the groove of the at least one rim of the spectacle frame,

receiving the blocking point of the ophthalmic lens and the horizontal direction Xl of the ophthalmic lens,

determining the shape of the bevel of the ophthalmic lens using a method according to claim 1 , and

cutting the ophthalmic lens according to the calculated bevel.

6. The method according to claim 5 , wherein the spectacle frame is selected and measured at a lens order side and the internal profile of the groove of the spectacle frame is transmitted to a computing device installed at a lens edger side where the calculation steps are processed.

7. The method according to claim 5 , wherein the cutting step is preceded at the order side.

8. An ophthalmic lens ordering method comprising the steps of:

selecting a spectacle frame,

ordering an ophthalmic lens cut according to claim 5 and,

fitting the cut ophthalmic lens in the selected spectacle frame.

9. A non-transitory computer program product comprising one or more stored sequence of instruction that is accessible to a processor and which, when executed by the processor, causes the processor to carry out at least one of the steps of claim 1 .

10. A non-transitory computer readable medium carrying one or more sequences of instructions of the computer program product of claim 9 .

11. A non-transitory computer program product comprising one or more stored sequence of instruction that is accessible to a processor and which, when executed by the processor, causes the processor to carry out at least one of the steps of claim 8 .

12. A method for determining the shape of the bevel of an ophthalmic lens so as to have the ophthalmic lens fit a given spectacle frame, the method comprising the steps of:

providing the three-dimensional (xi, yi, zi) internal profile of the groove of at least a rim of the spectacle frame expressed in the principal axes (Xf, Yf, Zf) of the spectacle frame and the length Pf of the periphery of the groove of the rim;

providing the blocking point of the ophthalmic lens and the horizontal direction Xl of the ophthalmic lens;

aligning the normal Zl to the surface of the ophthalmic lens at the blocking point with the Zf axe of the rim;

aligning the horizontal direction Xl of the ophthalmic lens with the Xf axe of the rim;

projecting the three-dimensional (xi, yi, zi) internal profile of the groove of the rim on the front face surface of the ophthalmic lens so as to obtain a three-dimension projected groove shape (xp, yp, zp); and

modifying the coordinates of each point of the two-dimensional groove shape (xp, yp) based on two correction coefficient coefficients, Rx for the coordinate xp and Ry for the coordinate yp, with Rx+Ry=1 so as to have the length Pp of the three-dimensional groove projected shape (xp, yp, zp) equal to the length Pf of the periphery of the internal profile of the groove of the rim so as to obtain the shape of the bevel of the ophthalmic lens,

wherein the modifying is performed iteratively based on the following equations:

X

k

+

1

=

X

k

×

(

1

+

R

x

×

[

P

f

-

P

p

Pf

]

)

Y

k

+

1

=

Y

k

×

(

1

+

R

y

×

[

P

f

-

P

p

Pf

]

)

.