Command/control unit and computer program for producing an ophthalmic lens comprising a step of laser marking in order to produce permanent etchings on one surface of said ophthalmic lens

A command/control unit, comprising a microprocessor and a memory, the memory having stored thereon a computer program that upon execution by the microprocessor causes the command/control unit to implement a process for manufacturing an ophthalmic lens with a laser-marking machine that marks a surface of the ophthalmic lens, the process implemented by the computer program including:

• a step of determining an operating point of the laser-marking machine, where said operating point characterizes geometric characteristics of permanent engravings to be produced by the laser-marking machine on the surface of the ophthalmic lens;
• a laser-marking step, carried out by said laser-marking machine, that produces the permanent engravings on the surface of said ophthalmic lens, the laser-marking machine configured to operate in accordance with the operating point for producing the permanent engravings on the surface of said ophthalmic lens,
• the laser-marking step producing first deformations on the surface, the first deformations generated by said laser-marking step each having a shape of craters comprising a recess formed in the surface and a rim surmounting the recess on the surface, said recess having a diameter and depth which define the geometric characteristics of the permanent engravings;
• and
• subsequent to said laser-marking step, a predetermined step that includes at least one of a coloring step and a varnishing step applied to the surface and to the permanent engravings on the surface, said predetermined step being carried out during a treatment time and at a temperature which is close to stress relaxation threshold values of a material of the ophthalmic lens and in a manner that applies thermal stresses to the surface and to the permanent engravings on the surface, the thermal stresses inflicted to the permanent engravings by said predetermined step characterized at least by the treatment time and the temperature and generating second deformations on the recesses and the rims, thus applying post-marking stresses to the first deformations,
• wherein said step of determining the operating point includes the following steps:
• determining a value, chosen from a plurality of post-marking stress levels predetermined as a function of predetermined ranges of geometric engraving characteristics and predetermined ranges of values representative of the deformation of the ophthalmic lens, for at least one treatment zone of the surface of the ophthalmic lens in which the permanent engravings are to be produced, that would result from i) the thermal stresses to be applied to the permanent engravings on the surface of the ophthalmic lens during the predetermined step, and from ii) data relating to the material from which the ophthalmic lens is formed;
• and
• deducing the operating point i) from the determined value representative of the post-marking stresses in the at least one treatment zone and ii) from the geometric characteristics of the permanent engravings to be produced by said laser-marking step.

A non-transitory computer-readable medium having stored thereon a computer program configured to be executed by a microprocessor of a command/control unit, said computer program including instructions configured to, upon execution by the microprocessor, cause the command/control unit to implement a process for manufacturing an ophthalmic lens with a laser-marking machine that marks a surface of the ophthalmic lens, wherein the process implemented by the computer program includes:

• a laser-marking step, carried out by said laser-marking machine, for producing permanent engravings on a surface of the ophthalmic lens, the laser-marking machine configured to operate in accordance with an operating point that characterizes geometric characteristics of the permanent engravings that the laser-marking machine will produce on the surface of the ophthalmic lens;
• at least one predetermined step subsequent to said laser-marking step that applies thermal stresses to the surface at a temperature which is close to a stress relaxation threshold value of at least one material from which the ophthalmic lens is formed;
• and
• determining, prior to said laser-marking step, the operating point of the laser-marking machine, based on the geometric characteristics of the permanent engravings to be produced on the surface of the ophthalmic lens,
• where said step of determining the operating point comprises the following steps:
• determining a value, chosen from a plurality of post-marking stress levels predetermined as a function of predetermined ranges of geometric engraving characteristics and predetermined ranges of values representative of the deformation of the ophthalmic lens, for at least one treatment zone of the surface in which the permanent engravings are to be produced, that would result from the thermal stresses of the at least one predetermined step subsequent to said laser-marking step, based on data characterizing the predetermined post-marking steps and based on data relating to the at least one material from which the ophthalmic lens is formed;
• and
• deducing the operating point from the determined value representative of the deformation of the ophthalmic lens in the at least one treatment zone and from the geometric characteristics of the permanent engravings to be produced by said laser-marking step.