Method for manufacturing an ophthalmic device by machining and manufacturing system configured to implement this method

Abstract

The invention provides a method for manufacturing an ophthalmic device by machining, the method comprising the steps of: providing (101) data representative of at least one desired surface to be machined on an ophthalmic device as a function of at least optical power; providing (102) at least one parameter representative of a state of wear of at least one position of a cutting edge of a cutting tool configured to machine the at least one desired surface of the ophthalmic device; determining (103) a machining strategy as a function of both the at least one desired surface and the at least one parameter representative of a state of wear; the machining strategy being selected from at least one of a first instruction (103a) to machine the desired surface with the cutting tool and a second instruction (103b) not to machine the desired surface with the cutting tool.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing ophthalmic devices by machining and a manufacturing system configured to carry out this method.

[0002] The present invention also relates to a command and control unit comprising system elements configured to run a computer program to implement at least some steps of a manufacturing method; and to a manufacturing system comprising such a command and control unit and configured to implement the method.

[0003] The present invention also relates to a computer program comprising instructions configured to implement at least some portions of the method when the computer program is run by a computer; and to a client-server communication interface for transmitting at least manufacturing data to a remote computer, the manufacturing data being determined by the computer program implementing at least some portions of the method, wherein the remote computer implements other portions of the method when the computer program is run in a command and control unit. Background Technology

[0004] Ophthalmic devices, such as spectacle lenses, or components for obtaining such spectacle lenses, such as molds, are known to be manufactured by machining methods performed by a machining system with machining tools.

[0005] Machining may include surface finishing, which includes at least one of roughing, finishing and / or grinding of the ophthalmic device in order to obtain at least one desired surface on the ophthalmic device.

[0006] The at least one desired surface on the ophthalmic device may be the surface of a lens blank or a semi-finished lens blank, from which spectacle lenses or molds for molding spectacle lenses are made directly.

[0007] The at least one desired surface can bring about some desired optical properties defined by the prescription of the wearer of the eyeglass lens.

[0008] Prescriptions can be defined by optical power design (including optical power in diopters) for use in spectacle lenses.

[0009] Machining uses cutting tools (such as diamond tools) that are configured to contact the ophthalmic device in order to remove the material used to make the ophthalmic device.

[0010] Specifically, the cutting tool includes a cutting edge that defines multiple contact points with the ophthalmic device.

[0011] The wear pattern along the cutting edge of the cutting tool is uneven, depending on the desired surface to be machined, as well as the material and basic curvature of the ophthalmic device.

[0012] This wear on the cutting tool can create defects on the desired surface to be machined, and these defects represent focal errors.

[0013] In this regard, a known method known as "tool wear compensation" can be used to attempt to compensate for the wear of the cutting edge of the cutting tool during machining.

[0014] French patent FR 2 984 197 from the applicant discloses such a tool wear compensation method. In particular, the patent describes a method related to correcting surface irregularities introduced in a reproducible manner, which includes the steps of determining the surface irregularities of a surface-finished lens and the transformation steps of using an irregularity model to compensate for the surface irregularities of the surface-finished lens.

[0015] This tool wear compensation method takes into account the surface irregularities of the machined surface. Summary of the Invention

[0016] This invention relates to a method for manufacturing ophthalmic devices by machining, which is simple and convenient to implement.

[0017] Accordingly, the present invention provides a method for manufacturing an ophthalmic device by machining, the method comprising the following steps:

[0018] - Provide data representing at least one desired / target surface to be machined on an ophthalmic device, based at least on optical power;

[0019] - Provide at least one parameter indicating the wear state of at least one location of the cutting edge of a cutting tool configured to machine at least one desired surface of an ophthalmic device;

[0020] - Determine the machining strategy based on both the at least one desired surface and the at least one parameter representing the wear state;

[0021] The machining strategy is selected from at least one of a first instruction to machine the at least one desired surface with the cutting tool and a second instruction not to machine the at least one desired surface with the cutting tool.

[0022] In other words, by means of the method according to the invention, taking into account the desired surface itself, it is possible to allow or not allow at least one desired surface to be machined, depending on at least one parameter of the wear state of at least one location of the cutting edge of the cutting tool.

[0023] Therefore, the method according to the invention can be considered a preventative method that takes into account the desired surface to be machined, the estimation or actual wear condition of at least one position of the cutting edge of the cutting tool (by at least one dedicated parameter), and the potential negative impacts of machining the desired surface with the cutting tool.

[0024] The preventative effect of the method according to the invention allows for the convenient management of machining strategies based on the estimated or actual wear condition at at least one location on the cutting edge of the cutting tool, in conjunction with the desired surface to be machined.

[0025] For example, when a desired surface is machined using a cutting tool, and another desired surface to be machined can meet the quality tolerance requirements, the risk of exceeding the quality tolerance range can be identified.

[0026] Therefore, the method can, for example, determine a machining strategy, according to which a second instruction will be issued to machine a desired surface without a cutting tool, and subsequently a first instruction will be issued to machine another desired surface with a cutting tool.

[0027] In other words, the method according to the invention can allow for the adjustment of ophthalmic device production in specialized factories (such as laboratories).

[0028] In addition to managing machining strategies based on quality tolerances, the method according to the invention can also conveniently improve the life of cutting tools while increasing laboratory productivity.

[0029] The following describes the advantageous and convenient features of the manufacturing method.

[0030] The at least one parameter indicating the wear condition can be a geometric parameter and / or a machining electrical parameter, such as electrical power or electrical intensity or electrical energy, and / or a machining vibration parameter.

[0031] At least one parameter representing the wear condition can be obtained by measuring the waviness on a predetermined reference surface and / or multiple desired machined surfaces and / or by electrical measurement of the machining power gradient and / or by accelerometer or acoustic measurement of the machining vibration gradient.

[0032] The method may include: providing at least one error map, such as an optical power error map, the at least one error map being characterized based on at least one desired surface and at least one parameter representing the wear state; and determining a machining strategy based on the at least one optical power error map.

[0033] As described above, the at least one error map can be an optical power error map, but it can also be a machining electrical parameter error map based on, for example, electrical power, electrical intensity, or electrical energy or their gradient, or it can also be a machining vibration parameter error map based on, for example, vibration power, vibration amplitude, vibration shape, vibration energy or Fourier transform or wavelet transform.

[0034] In other words, taking into account the desired surface itself, it is possible to allow or not allow at least one desired surface to be machined, depending on both the at least one parameter of the wear condition of at least one location of the cutting edge of the cutting tool and the predicted optical power error or other more general parameter error that may occur on an ophthalmic device.

[0035] Therefore, the potential negative impact of machining a desired surface with a cutting tool can be represented by the defects estimated on the error map.

[0036] By comparing the desired surface to be machined with the error map, it can be identified that there is a risk of exceeding the quality tolerance when machining one desired surface with a cutting tool, while another desired surface to be machined will meet the quality tolerance.

[0037] The at least one error map (e.g., an optical power error map) may represent the refractive index and / or fundamental curvature of a predetermined reference surface and / or a predetermined material, and the at least one error map is characterized by surface optical power defects at least at a position corresponding to the center of the predetermined reference surface and / or by annular defects at least around the center of the predetermined reference surface.

[0038] Surface focal length defects and / or annular defects can represent a portion of the global optical focal length error, which also includes positioning errors and curvature errors.

[0039] The method may include: providing multiple error maps arranged in a machining domain, locating the at least one desired surface to be machined in the machining domain, comparing the at least one desired surface to be machined with a corresponding predetermined reference surface, and determining a machining strategy based on the comparison results.

[0040] The machining domain may include at least one first region defining an acceptable error map and at least one second region defining an unacceptable error map, both of which depend at least on the wear condition of at least one location of the cutting edge of the cutting tool.

[0041] The at least one first region and the at least one second region can be separated by at least one quality tolerance threshold.

[0042] The machining strategy can be determined based on at least one parameter of the ophthalmic device on which the desired surface is to be machined, the at least one parameter being selected from material parameters, curvature parameters, optical power parameters, diameter parameters, and thickness parameters.

[0043] The machining strategy may include a third instruction to change the cutting tool and / or a fourth instruction to select another desired surface to be machined and / or a fifth instruction to machine the desired surface by a selected machining device among a plurality of machining devices, and when the second instruction is selected, at least one of the third, fourth and fifth instructions is also selected.

[0044] The fourth instruction for selecting another desired surface can be used for the same ophthalmic device or for another ophthalmic device.

[0045] According to a second aspect, the present invention also provides a command and control unit comprising system elements configured to run a computer program to manufacture an ophthalmic device by machining by performing the following steps: providing data representing at least one desired surface to be machined on the ophthalmic device, at least according to optical power; providing at least one parameter representing the wear state of at least one location of the cutting edge of a cutting tool configured to machine the at least one desired surface of the ophthalmic device; determining a machining strategy based on both the at least one desired surface and the at least one parameter representing the wear state; the machining strategy being selected from at least one of a first instruction to machine the at least one desired surface with the cutting tool and a second instruction not to machine the at least one desired surface with the cutting tool.

[0046] According to a third aspect, the present invention further provides a manufacturing system comprising at least one machining apparatus having a cutting tool, and a command and control unit, the system being configured to manufacture an ophthalmic device by machining through the following steps: providing data representing at least one desired surface to be machined on the ophthalmic device, at least according to optical power; providing at least one parameter representing the wear state of at least one location of the cutting edge of the cutting tool, the cutting tool being configured to machine the at least one desired surface of the ophthalmic device; determining a machining strategy based on both the at least one desired surface and the at least one parameter representing the wear state; the machining strategy being selected from at least one of a first instruction to machine the at least one desired surface with the cutting tool and a second instruction not to machine the at least one desired surface with the cutting tool.

[0047] The manufacturing system may include multiple machining units, and the machining strategy includes a third instruction to change the cutting tool and / or a fourth instruction to select another desired surface to be machined and / or a fifth instruction to machine the desired surface by a selected machining unit among the multiple machining units, and when the second instruction is selected, at least one of the third, fourth and fifth instructions is also selected.

[0048] At least one of these machining apparatuses can be configured to machine several desired surfaces simultaneously or sequentially on a single support or on several supports.

[0049] According to a fourth aspect, the present invention also provides a computer program comprising instructions configured to manufacture an ophthalmic device by machining by performing the following steps: providing data representing at least one desired surface to be machined on the ophthalmic device, at least according to optical power; providing at least one parameter representing the wear state of at least one location of the cutting edge of a cutting tool configured to machine the at least one desired surface of the ophthalmic device; determining a machining strategy based on both the at least one desired surface and the at least one parameter representing the wear state; and, when the computer program is run by a computer, the machining strategy is selected from at least one of a first instruction to machine the at least one desired surface with the cutting tool and a second instruction not to machine the at least one desired surface with the cutting tool.

[0050] According to a fifth aspect, the present invention further provides a client-server communication interface for transmitting to a remote computer manufacturing data, such as a manufacturing document containing a machining strategy, for manufacturing an ophthalmic device by machining. This data is determined by a computer program running in a command and control unit configured to perform the following steps: providing data representing at least one desired surface to be machined on the ophthalmic device, at least based on optical power; providing at least one parameter representing the wear state of at least one location of the cutting edge of a cutting tool configured to machine the at least one desired surface of the ophthalmic device; determining a machining strategy based on both the at least one desired surface and the at least one parameter representing the wear state; the machining strategy being selected from at least one of a first instruction to machine the at least one desired surface with the cutting tool and a second instruction not to machine the at least one desired surface with the cutting tool, and the remote computer being configured to perform or not perform machining according to the machining strategy.

[0051] It should be noted that the method according to the invention can be implemented in combination with or sequentially with a tool wear compensation method that takes into account the surface irregularities of the machined surface (such as the method described in the applicant's French patent FR 2 984 197) and / or another tool wear compensation method developed by the applicant that takes into account the irregularities of the cutting tool itself due to its uneven wear state.

[0052] The so-called tool wear compensation method is a "remedial" method, while the method according to the present invention is a "preventive" method, thus allowing for the implementation of precise solutions for managing both cutting tool life and ophthalmic device manufacturing processes. Attached Figure Description

[0053] The description of the invention will now continue with a detailed description of the embodiments given below by way of non-limiting examples and with reference to the accompanying drawings.

[0054] Figure 1 This is a schematic diagram of a manufacturing system configured to implement a method for manufacturing ophthalmic devices by machining.

[0055] Figure 2 A client-server communication interface is illustrated in the diagram. This interface includes system components configured to transmit at least one configuration parameter determined by the method according to the invention to a remote data processing system.

[0056] Figure 3 Partially and schematically depicted Figure 1 The cutting tool of the manufacturing system shown is oriented towards the ophthalmic device to be machined.

[0057] Figure 4 Partially and schematically depicting the relationship with Figure 3 The cutting tool shown has two different contact angles corresponding to multiple positions on one cutting edge.

[0058] Figure 5 A multidimensional graphical representation of the optical surface focal error generated by the cutting tool at a predetermined reference surface at a location on the cutting edge of the cutting tool is shown, depending on the determined wear condition of the cutting tool.

[0059] Figure 6 This is a block diagram illustrating the invention by means of... Figure 1 and Figure 2 The above describes the operational steps of the manufacturing system and / or client-server communication interface for manufacturing ophthalmic devices.

[0060] Figure 7 It is a block diagram that illustrates... Figure 6 More detailed operating steps of the method for manufacturing an ophthalmic device according to the first embodiment shown above.

[0061] Figure 8 It is a block diagram that illustrates... Figure 6 More detailed operating steps of the method for manufacturing an ophthalmic device according to the second embodiment shown above.

[0062] Figure 9 A multidimensional graphical representation of a machining domain is shown, which includes multiple optical magnification error maps and a quality tolerance threshold that separates a first acceptable region from a second unacceptable region. Each of the multiple optical magnification error maps corresponds to a parameter representing the wear state at a location on the cutting edge of a cutting tool, obtained by measuring the waviness on a predetermined reference surface.

[0063] Figure 10 A multidimensional graphical representation of another parameter is shown, which represents the wear state at a location on the cutting edge of the cutting tool, obtained by accelerometer measurement of the machining vibration gradient.

[0064] Figure 11 It shows Figure 10 The above shows the correspondence between accelerometer measurements of vibration gradients during machining and focal error on a machined ophthalmic device.

[0065] Figure 12 A multidimensional graphical representation of another parameter is shown, which represents the wear state at a location on the cutting edge of the cutting tool, obtained by acoustic measurement of the machining vibration gradient.

[0066] Figure 13 A multidimensional graphical representation of another parameter is shown, which represents the wear state at a location on the cutting edge of the cutting tool, obtained by electrical measurement of the machining power gradient of the manufacturing system. Detailed Implementation

[0067] The present invention relates to a method for manufacturing ophthalmic devices, the method comprising at least one machining step, particularly a cutting step also known as a surface finishing step.

[0068] Figure 1 A manufacturing system is shown, configured to perform machining steps on at least one desired surface on a component, which is an ophthalmic device 10 or a mold intended to mold such an ophthalmic device therein. Such a mold can, for example, be used to manufacture semi-finished or finished lenses.

[0069] The term ophthalmic device will be used to refer to lens blanks, semi-finished lenses, finished lenses, and molds.

[0070] The system includes a manufacturing machine 1 and system components generally formed by at least one command and control unit 2, which is configured to communicate with a data processing system (or control unit) of the machine 1 and to run a computer program having instructions configured to perform at least the machining steps of the method when the computer program is run by a computer.

[0071] Machine 1 here refers to a digitally controlled "free-form" turning machine 1, where digital control represents a collection of equipment and software whose function is to give movement instructions to all components of Machine 1.

[0072] Machine 1 includes a movable machining arm 7 and a data processing system or control unit (not shown), on which a cutting tool 20 with a cutting edge is mounted, and the data processing system or control unit is configured to control the arm 7 and thus control the cutting tool 20.

[0073] Machine 1 is configured to machine a desired surface on at least one face 12 of ophthalmic device 10 by turning and / or surface finishing.

[0074] The command and control unit 2 includes a microprocessor 3 having a memory 4, particularly a non-volatile memory, which allows it to load and store computer programs (also called software) that, when implemented in the microprocessor 3, enable the implementation of the method according to the invention.

[0075] The non-volatile memory 4 is, for example, a ROM ("Read-Only Memory") type.

[0076] The command and control unit 2 further includes a memory 5, particularly a volatile memory, thereby allowing data to be stored during the implementation of the software and the implementation of the method.

[0077] The volatile memory 5 is, for example, of the type RAM or EEPROM ("Random Access Memory" and "Electrically Erasable Programmable Read-Only Memory", respectively).

[0078] Command and control units can be integrated into the machine, at least partially. In other words, control units can be located partially or entirely outside the machine.

[0079] The command and control unit may form at least part of the machine and may include one or more command and control modules located inside and / or outside the machine.

[0080] The ophthalmic device 10 can be an ophthalmic lens and / or examination piece. When the part being machined is not a mold but directly an ophthalmic lens, the machine 1 can also be configured to polish the surfaces and / or grind the outer peripheral edges. For example, the machine 1 can be configured to rough-machine one or more surfaces and then finish-machine them to form an ophthalmic lens.

[0081] Machining tool 10 here is, for example, a diamond turning tool (see details). Figure 3 and Figure 4 ).

[0082] Command and control unit 2 is configured to command and control at least some of the steps in the manufacturing method described below.

[0083] Figure 2 A client-server communication interface 30 is shown, including, for example, a so-called vendor side 9a and another so-called client side 9b, and these two sides communicate via an Internet interface 6.

[0084] The supplier side includes server 9a, which is linked to or connected to the data processing system. Figure 1 The same type of command and control unit 2a is used, and the server 9a is configured to communicate with the Internet interface 6.

[0085] The client side 9b is configured to communicate with the Internet interface 6 and connect to a data processing system or a command and control unit 2b of the same type as the supplier side.

[0086] In addition, the client-side command and control unit 2b is linked to... Figure 1 The same type of manufacturing machine 1b is used to manufacture at least the first face of the ophthalmic device 10b.

[0087] For example, the command and control unit 2b on the client side is configured to receive by the user some parameters about the ophthalmic device to be machined and / or about the cutting tool and / or about the manufacturing method intended to be implemented for machining the ophthalmic device.

[0088] For example, parameters of ophthalmic device 10b may include at least one of the following data: geometric properties and / or optical functions of the desired ophthalmic surface to be manufactured and / or inherent parameters (such as refractive index) of the material of the component to be machined.

[0089] For example, parameters relating to a cutting tool used to machine a desired surface can be parameters representing the wear condition at at least one location on the cutting edge of the cutting tool.

[0090] For example, the parameters of the manufacturing method to be implemented can be a machining strategy selected from at least one of a first instruction to machine the desired surface with a cutting tool and a second instruction to machine the desired surface without a cutting tool.

[0091] The client-side command and control unit 2b sends the received data to the supplier-side command and control unit 2a via the Internet 6 interface and server 9a to determine manufacturing documents and operating parameters.

[0092] If the client-side command and control unit 2b receives some parameters about the ophthalmic device to be machined and / or about the cutting tool, the supplier-side command and control unit 2a executes its contained computer program to implement steps, for example, to determine the machining strategy based on both the desired surface and parameters indicating the wear state.

[0093] By using server 9a and Internet interface 6, the supplier-side command and control unit 2a sends manufacturing documents and operating parameters (especially machining strategies) to the client-side command and control unit 2b.

[0094] The client-side command and control unit 2b is configured to execute software to implement additional steps of the method for manufacturing the part by using manufacturing documents and operating parameters (in particular machining strategies) to perform or not perform machining of the desired surface on the part by the manufacturing system 1b, which is an ophthalmic device or a mold intended to mold such an ophthalmic device therein.

[0095] In one variant, the manufacturing system may be located on the supplier side, such that the supplier-side command and control unit 2a is configured to both determine the machining strategy and machine or not machine the desired surface on the part, which is an ophthalmic device or a mold intended to mold such an ophthalmic device therein.

[0096] refer to Figure 3 and Figure 4 The component to be machined here is an ophthalmic device, which includes a surface here called upper surface 12, a lower surface 11 opposite to upper surface 12, and an outer peripheral edge 13 connecting lower surface 11 and upper surface 12.

[0097] For example, the upper surface 12 is configured to form a first surface (also called the rear surface), and the lower surface 11 is configured to form a second surface (also called the front surface). The second surface is opposite to the first surface.

[0098] The outer peripheral edge 13 is configured to form an outer peripheral profile having a first connecting portion 15 connecting the outer peripheral edge 13 to the first surface 12 and a second connecting portion 14 connecting the outer peripheral edge 13 to the second surface 11.

[0099] Here, the parts to be machined are maintained by a retaining system 8 (such as a sealing resistor) installed in the machine.

[0100] The retaining system 8 may include, for example, an adhesive film (not shown) having an adhesive surface configured to be fixed on the bottom 11; or another system may be used, such as an alloy and / or a clamping device.

[0101] The holding system 8 is configured to be mounted on the spindle axis (not shown) of the machine, and the spindle axis rotates during machining, causing the ophthalmic device 10 to rotate itself during machining.

[0102] The machine includes three directions: a first direction 16 (i.e., the X direction), a second direction 18 (i.e., the Y direction) perpendicular to the first direction 16, and a third direction 17 (i.e., the Z direction) perpendicular to both the first direction 16 and the second direction 18.

[0103] The position of the cutting tool 20 is defined by the first direction, the second direction and the third direction 16 to 18 in the machine.

[0104] Here, Z direction 17 corresponds to the turning axis (also called the turning center or rotation axis) of the ophthalmic device 10.

[0105] The cutting tool 20 here includes: a pin 21 configured to be fastened to a movable machining arm, a base 22 protruding from the pin 21, a tool support 23 formed by a protrusion of the base 22 on the opposite side of the pin 21, and a diamond tool 24 or end tool fixed to the tool support 23.

[0106] The diamond tool 24 can be half-radius or full-radius type, and usually has a predetermined opening angle (in degrees).

[0107] A full-radius diamond tool can be mounted on the cutting tool 20 such that the diamond tool 24 is tilted relative to the tool support 23 to form a tool with an asymmetrical opening angle.

[0108] The asymmetrical arrangement of the opening angle can be defined by a plane including the turning axis 17 (or the Z direction), the Y direction 18, and the tool center.

[0109] Figure 4 The two contact angles α', α'' of the cutting tool at two different contact points 25' and 25'' are partially and schematically depicted, and help to define the contact point and contact angle at a certain position on the cutting edge of the diamond tool 24.

[0110] The upper figure relates to surface 12' with low curvature, while the lower figure relates to another surface 12'' with high curvature.

[0111] These figures also show the turning axis 17 (also known as the rotation axis) in the Z direction, and the parallel axis of the rotation axis 18 in the Z direction to aid understanding.

[0112] The diamond tool 24 is schematically represented by a circle. Contact points 25' and 25'' are the contact points between the tool and the corresponding surfaces 12' and 12''.

[0113] The tool angles α' and α'' are defined as the angles between the rotation axes 17 and 18 and the axes passing through the reference point 26 and contact points 25' and 25'' of the diamond tool 24.

[0114] Since axes 17 and 18 are parallel, the angles between axes 18 or between axes 17 are the same.

[0115] The reference point can be the center of the diamond tool or any other point on the tool, as long as that point remains the same for every contact point in the diamond tool's reference frame.

[0116] As shown in the figure, the contact angle depends on the location of the contact point.

[0117] Therefore, the contact angle can depend on the curvature of the surface and / or the position of the diamond tool on the surface.

[0118] In the remainder of the instruction manual, the term cutting tool is used interchangeably with diamond tool.

[0119] In the Rx laboratory, the actual final step in surface formation is a turning operation using a cutting tool. Initially, the cutting tool can be approximated as circular based on the specifications provided by the cutting tool manufacturer, having a radius of, for example, 30 µm to 12 mm, preferably 2 mm to 5 mm.

[0120] During turning (also known as surface finishing or cutting), the point of contact between the ophthalmic device and the cutting tool moves along this circular portion. This results in uneven wear along the tool radius, depending on the surface to be obtained.

[0121] Roundness defects in the cutting tool are replicated on the machined surface and can lead to localized or global surface defects, such as incorrect power design, ring defects, and center defects on machined or semi-finished lenses. Similar defects can also occur on semi-finished molded surfaces. This can result in incorrect power design on the lens.

[0122] exist Figure 5 The above-mentioned defects are illustrated in the figure, which shows the average spherical error (in diopters) along the radius of the machined ophthalmic device based on a predetermined reference surface and depending on the number of lenses cut, where the number of lenses cut represents the wear of the cutting tool at a defined position on its cutting edge.

[0123] Figure 5 It is clearly shown that as the number of machined devices increases, the surface focal length defects at the center of the ophthalmic device (where the radius is equal to 0 mm) increase. These defects also represent so-called annular defects.

[0124] It should be noted that surface focal length defects and / or annular defects can represent a portion of the global optical focal length error, which also includes other errors such as positioning errors and curvature errors.

[0125] Figure 6 The main steps of a method 100 for fabricating a desired surface on an ophthalmic device are shown, as described above. Figure 1 and Figure 2 The described manufacturing system and / or client-server communication interface implementation.

[0126] The method includes step 101: providing data representing at least one desired surface to be machined on the ophthalmic device, based at least on the optical power to be provided by the ophthalmic device.

[0127] For example, data representing at least one desired surface to be machined on an ophthalmic device may be geometric properties and / or optical functions and / or material refractive index.

[0128] The method includes step 102: providing at least one parameter representing the wear state of at least one location of the cutting edge of a cutting tool configured to machine the at least one desired surface of an ophthalmic device.

[0129] The method includes step 103: determining a machining strategy based on both the at least one desired surface received in step 101 and the at least one parameter representing the wear state received in step 102.

[0130] Machining strategies can be selected from at least one of the following:

[0131] - First instruction 103a: Machining the at least one desired surface with a cutting tool:

[0132] - A second instruction 103b that machines the at least one desired surface without using a cutting tool; and when the second instruction is selected...

[0133] - Third instruction 103i for changing cutting tools:

[0134] - Fourth instruction 103i for selecting another desired surface to be machined on the same ophthalmic device or on another ophthalmic device;

[0135] - Fifth instruction 103i: to machine the desired surface by selecting a machining device from among multiple machining devices.

[0136] The machining strategy can be determined based on at least one parameter of the ophthalmic device on which the desired surface is to be machined, the at least one parameter being selected from material parameters, curvature parameters, optical power parameters, diameter parameters, and thickness parameters.

[0137] Figure 7 Step 102, which involves providing at least one parameter representing the wear condition at at least one location of the cutting edge of a cutting tool, is shown in more detail. This step may include:

[0138] - Step 102a: Provide the geometric parameters of the cutting tool at the position of the cutting edge; and / or

[0139] - Step 102b: Provide the machining vibration parameters of the machining apparatus when using a cutting tool; and / or

[0140] - Step 102c: Provide the machining electrical parameters (such as power, strength and / or energy) of the machining apparatus when using a cutting tool.

[0141] In each case, these parameters directly or indirectly represent the wear condition at the location of the cutting edge of the cutting tool, and are therefore related to the cutting tool.

[0142] In step 102a, the waviness on the predetermined reference surface that has been machined can be measured (see...). Figure 9 This is used to obtain parameters representing the wear state.

[0143] In step 102b, the vibration gradient of the machining process can be measured by an accelerometer (see [reference]). Figure 10 and Figure 11 ), or by acoustic measurement of the vibration gradient during machining (see Figure 12 This is used to obtain parameters representing the wear state.

[0144] In step 102c, this can be achieved by electrical measurement of the machining power gradient (see...). Figure 13 This is used to obtain parameters representing the wear state.

[0145] It is also possible to take into account the estimated or actual number of desired surfaces that have already been machined with cutting tools.

[0146] Next, the method may include step 104: providing or determining at least one optical power error map, which is characterized based at least on both the desired surface received in step 101 and the parameters representing the wear state received in steps 102a-c.

[0147] Next, the method may include step 103: determining a machining strategy based on the at least one optical power error map received or determined in step 104.

[0148] The at least one optical power error map can represent the refractive index and / or fundamental curvature of a predetermined reference surface and / or a predetermined material.

[0149] The at least one optical power error map can be composed of surface optical power defects (such as those at least at a position corresponding to the center of a predetermined reference surface). Figure 5 (as shown) and / or consists of annular defects (see) at least around the center of a predetermined reference surface. Figure 9 ) is used to characterize it.

[0150] Figure 8 Further steps of the method according to another embodiment are shown, including: step 105: providing a plurality of optical power error maps arranged in a machining domain; step 106: locating at least one desired surface to be machined in the machining domain; step 107: comparing the at least one desired surface to be machined with a corresponding predetermined reference surface; and the following step 103: determining a machining strategy based on the comparison results.

[0151] This machining domain is Figure 9 The above is presented graphically.

[0152] The machining domain is determined based on the optical power (in diopters, here referring to the back surface) and the refractive index (denoted as n) of the surface being machined.

[0153] As explained above, each of the optical power error maps 50 represents a predetermined reference surface for the refractive index and basic curvature or average curvature of a predetermined material; such that these optical power error maps are distributed over multiple regions in the machining domain.

[0154] Each of the optical power error diagrams in Figure 50 is also... Figure 5 The transformation of surface focal length defects (such as spherical optical errors) is shown, which are displayed as loops around the center of a predetermined reference surface.

[0155] exist Figure 9 In the example shown, the machining domain includes a quality tolerance threshold T, which is shown as a dashed line and separates a first region R1 that defines an acceptable optical power error map from a second region R2 that defines an unacceptable optical power error map. Thus, both the first region R1 and the second region R2 depend on the wear condition at the location of the cutting tool's edge.

[0156] As mentioned above... Figure 8 Once the desired surface to be machined is located in the machining domain, the machining strategy can be determined based on this machining domain.

[0157] For example, if the corresponding optical power error map is in the first region R1 for the desired surface, the determined machining strategy may be to machine the desired surface with a cutting tool; while if the corresponding optical power error map is in the second region R2 for the same desired surface, the determined machining strategy may be to machine the desired surface without a cutting tool, but instead to change the cutting tool and / or select another desired surface to be machined on another ophthalmic device.

[0158] The command to change the cutting tool can be to replace the cutting tool with another cutting tool, or to select another cutting tool within the same machine.

[0159] Figure 10 and Figure 11 A graphical representation of another parameter is shown, which represents the wear condition at a location on the cutting edge of the cutting tool, specifically obtained by accelerometer measurement of the machining vibration gradient.

[0160] Figure 10 The signals measured by the accelerometer sensor during machining of the desired surface are shown, including the positive P+ factor and the negative N- factor. Figure 11 It can be equivalent to the corresponding representation of the optical focal length error diagram, showing that when the cutting tool produces annular defects RD on the machined surface 12, some peak values ​​Pk and valley values ​​V may appear on the signal.

[0161] It should be noted that the signal at the center of the surface (on the right side of the graph) is not representative when the cutting tool starts or stops cutting.

[0162] Figure 12 A graphical representation of another parameter is shown, which represents the wear condition at a location on the cutting edge of the cutting tool, specifically obtained through acoustic measurements of the machining vibration gradient.

[0163] In particular, Figure 12 The diagram shows signals measured by acoustic sensors mounted on the cutting tool or holding device for worn tools and for new tools.

[0164] It can be seen that, except near the contour, the acoustic energy signal S1 of the new tool is basically linear and stable from the center of the surface to the contour (from right to left on the curve); while the acoustic signal S2 of the worn tool is not linear and not stable from the center of the surface to the contour.

[0165] Therefore, signals S1 and S2 can reflect defects on the machined surface that are acceptable or unacceptable, for example, based on the vibration threshold, as explained above.

[0166] Figure 13A graphical representation of another parameter is shown, which represents the wear condition at a location on the cutting edge of the cutting tool, specifically obtained through electrical measurement of the machining power gradient of the manufacturing system.

[0167] In particular, Figure 13 The signal P, measured by a diopter measuring device or a current measuring device, is shown depending on the number of lenses cut (Ni). The number of lenses cut indicates the wear of the cutting tool at a specific location on its edge.

[0168] In particular, Figure 13 The diagram shows that the electrical power P increases significantly during the first number of N1 machined surfaces, then increases slowly during the second number of N2 machined surfaces, where N2 is greater than N1, and then increases dramatically during the third number of N3 machined surfaces.

[0169] Therefore, signal P can also reflect defects on machined surfaces that are acceptable or unacceptable, for example, based on electrical power thresholds, as explained above.

[0170] It should be noted that the manufacturing system may include one or more machining devices as described above, and / or at least one of the machining devices may be configured to simultaneously or sequentially machine several desired surfaces on a single support or several supports.

[0171] In this regard, machining strategies may include a fourth instruction to select another desired surface to be machined on the same ophthalmic device or on another ophthalmic device and / or a fifth instruction to machine the desired surface by a selected machining device among a plurality of machining devices.

[0172] By means of the method according to the invention, taking into account the desired surface itself, it is possible to allow or not allow at least one desired surface to be machined, depending on at least one parameter of the wear state at at least one location of the cutting edge of the cutting tool.

[0173] Therefore, the method according to the invention can be equivalent to a preventive method that takes into account the desired surface to be machined, the estimated or actual wear condition of at least one position of the cutting edge of the cutting tool (by at least one dedicated parameter), and the potential negative impact of machining the desired surface with the cutting tool, which is represented by defects estimated on the optical power error map.

[0174] The preventative effect of the method according to the invention allows for the convenient management of machining strategies based on the estimated or actual wear condition at at least one location on the cutting edge of the cutting tool, combined with the desired surface to be machined.

[0175] For example, it is possible to identify the risk of exceeding quality tolerances when machining a desired surface with a cutting tool, while another desired surface to be machined will meet the quality tolerances.

[0176] Therefore, the method can, for example, determine a machining strategy, according to which a second instruction will be sent to machine a desired surface without a cutting tool, and subsequently a first instruction will be sent to machine another desired surface with a cutting tool.

[0177] In other words, considering the desired surface itself, it may be permissible or impermissible to machine at least one desired surface, depending on both the at least one parameter of the wear condition at at least one location of the cutting tool's edge and the predicted optical power error that may occur on an ophthalmic device.

[0178] Therefore, the potential negative impact of machining a desired surface with a cutting tool can be represented by the defects shown on the optical power error diagram.

[0179] By comparing the desired surface to be machined with the optical power error map, it can be identified that there is a risk of exceeding the quality tolerance when machining one desired surface with a cutting tool, while the other desired surface to be machined will meet the quality tolerance.

[0180] In other words, the method according to the invention can allow for the adjustment of ophthalmic device production in specialized factories (such as laboratories).

[0181] In addition to managing machining strategies based on quality tolerances, the method according to the invention can also conveniently improve the life of cutting tools while increasing laboratory productivity.

[0182] As explained above, it should be noted that the method according to the invention can be implemented in combination with or sequentially with a tool wear compensation method that takes into account the surface irregularities of the machined surface (such as the method described in the applicant's French patent FR 2 984 197) and / or another tool wear compensation method developed by the applicant that takes into account the irregularities of the cutting tool itself due to its uneven wear state.

[0183] Specifically, when calculating surface description data intended to be loaded into the circular portion of a surface machining machine, the cutting tool can be considered. The tool position is recalculated to compensate for the influence of the cutting tool. The recalculated tool position can be an X position or a Y position, preferably a Z tool position or a combination of X / Y / Z positions, or any other kind of degree of freedom position. This solution is based on the calculation of a cutting tool position compensation map. The compensated surface description data represents the surface of the ophthalmic device to be obtained by machining with a cutting tool, and the compensated surface description data is used. The compensated surface description data depends on the cutting tool and the contact point between the cutting tools.

[0184] For example, the method includes providing surface description data representing a surface of an ophthalmic device; providing contact data based on the surface description data, the contact data representing contact points used to obtain the surface represented by the surface description data with a cutting tool, the contact points being contact points between the cutting tool and a blank surface used to obtain the surface of an optical element, and the contact points being defined in a cutting tool coordinate system; generating a compensation map using a transfer function, the input of the transfer function being at least the contact data, and the output of the transfer function being the compensation map; and determining compensated surface description data based on the generated compensation map and the surface description data.

[0185] The step of generating the compensation map may include providing material description data representing the interaction between the material of the cutting tool and / or the material of the blank and / or the material of the ophthalmic device and the material of the cutting tool during cutting to obtain a desired surface, and determining the transfer function based at least on the provided material description data.

[0186] The step of generating the compensation map may further include: providing reference element description data representing the surface of an element previously cut by a cutting tool, and determining a transfer function based at least on the provided reference element description data; and / or providing a prediction model that predicts the wear of the cutting tool under given conditions, and determining the transfer function based at least on the predicted wear of the cutting tool.

[0187] The predictive model can be a trained machine learning model.

[0188] The step of generating the compensation map may further include providing the cutting speed and / or cutting depth at each contact point; and determining the transfer function based at least on the provided cutting speed.

[0189] The so-called tool wear compensation method is a "remedial" method, while the method according to the present invention is a "preventive" method, thus allowing for a precise solution for managing both cutting tool life and ophthalmic device manufacturing processes.

[0190] More generally, it should be noted that the present invention is not limited to the examples described and presented.

Claims

1. A method for manufacturing an ophthalmic device (10) by machining, the method comprising: - Provide (101) data, at least in terms of optical power, representing at least one desired surface to be machined on the ophthalmic device; - Provide (102) at least one parameter representing the wear state at at least one location of the cutting edge of a cutting tool, the cutting tool being configured to machine the at least one desired surface of the ophthalmic device; - Determine the machining strategy (103) based on both the at least one desired surface and the at least one parameter representing the wear state; The machining strategy is selected from at least one of a first instruction (103a) to machine the at least one desired surface with the cutting tool and a second instruction (103b) to machine the at least one desired surface without the cutting tool.

2. The method according to claim 1, wherein, The at least one parameter representing the wear state is a geometric parameter and / or a machining electrical parameter and / or a machining vibration parameter.

3. The method according to claim 2, wherein, The at least one parameter representing the wear state is obtained by measuring the waviness on a predetermined reference surface and / or multiple desired machined surfaces and / or by electrical measurement of the machining power gradient and / or by accelerometer or acoustic measurement of the machining vibration gradient.

4. The method according to any one of claims 1 to 3, comprising providing (105) at least one error map (50) and determining the machining strategy based on the at least one error map, the at least one error map being characterized based on at least one desired surface and at least one parameter representing the wear state.

5. The method according to claim 4, wherein, The at least one error map (50) represents the refractive index and / or fundamental curvature of a predetermined reference surface and / or a predetermined material, and the at least one error map is characterized by surface focal length defects at least at a position corresponding to the center of the predetermined reference surface and / or by annular defects at least around the center of the predetermined reference surface.

6. The method according to any one of claims 4 and 5, comprising providing (50) a plurality of error maps (50) arranged in a machining domain, locating (106) the at least one desired surface to be machined in the machining domain, comparing (107) the at least one desired surface to be machined with a corresponding predetermined reference surface, and determining (103) the machining strategy based on the comparison result.

7. The method according to claim 6, wherein, The machining domain includes at least one first region (R1) defining an acceptable error map (50) and at least one second region (R2) defining an unacceptable error map, both the first region and the second region depending at least on the wear condition of at least one location of the cutting edge of the cutting tool.

8. The method according to claim 7, wherein, The at least one first region (R1) and the at least one second region (R2) are separated by at least one quality tolerance threshold (T).

9. The method according to any one of claims 1 to 8, wherein, The machining strategy is determined based on at least one parameter of the ophthalmic device on which the desired surface is to be machined, the at least one parameter being selected from material parameters, curvature parameters, optical power parameters, diameter parameters, and thickness parameters.

10. The method according to any one of claims 1 to 9, wherein, The machining strategy includes a third instruction to change the cutting tool and / or a fourth instruction to select another desired surface to be machined and / or a fifth instruction to machine the desired surface by a selected machining device from a plurality of machining devices, and when the second instruction is selected, at least one of the third instruction, the fourth instruction and the fifth instruction is also selected.

11. A command and control unit comprising system elements configured to run a computer program to manufacture an ophthalmic device by machining by performing the following steps: providing data representing at least one desired surface to be machined on the ophthalmic device, at least according to optical power; providing at least one parameter representing a wear state of at least one location of a cutting edge of a cutting tool configured to machine the at least one desired surface of the ophthalmic device; determining a machining strategy based on both the at least one desired surface and the at least one parameter representing the wear state; the machining strategy being selected from at least one of a first instruction to machine the at least one desired surface with the cutting tool and a second instruction not to machine the at least one desired surface with the cutting tool.

12. A manufacturing system comprising at least one machining apparatus having at least one cutting tool, and a command and control unit, the system being configured to manufacture an ophthalmic device by machining by means of the following steps: providing data representing at least one desired surface to be machined on the ophthalmic device, at least according to optical power; providing at least one parameter representing a wear state of at least one location of the cutting edge of the cutting tool, the cutting tool being configured to machine the at least one desired surface of the ophthalmic device; determining a machining strategy based on both the at least one desired surface and the at least one parameter representing the wear state; the machining strategy being selected from at least one of a first instruction to machine the at least one desired surface with the cutting tool and a second instruction not to machine the at least one desired surface with the cutting tool.

13. The manufacturing system according to claim 12, wherein, The manufacturing system includes multiple machining units, and the machining strategy includes a third instruction to change the cutting tool and / or a fourth instruction to select another desired surface to be machined and / or a fifth instruction to machine the desired surface by a selected machining unit among the multiple machining units, and when the second instruction is selected, at least one of the third instruction, the fourth instruction and the fifth instruction is also selected.

14. A computer program comprising instructions configured to manufacture an ophthalmic device by machining by performing the following steps: providing data representing at least one desired surface to be machined on the ophthalmic device, at least according to optical power; providing at least one parameter representing a wear state of at least one location of a cutting edge of a cutting tool configured to machine the at least one desired surface of the ophthalmic device; determining a machining strategy based on both the at least one desired surface and the at least one parameter representing the wear state; and, when the computer program is run by a computer, the machining strategy being selected from at least one of a first instruction to machine the at least one desired surface with the cutting tool and a second instruction not to machine the at least one desired surface with the cutting tool.

15. A client-server communication interface for transmitting to a remote computer at least manufacturing data, such as a manufacturing document containing a machining strategy, for manufacturing an ophthalmic device by machining; wherein the manufacturing data is determined by a computer program running in a command and control unit, the command and control unit being configured to perform the following steps: providing data representing at least one desired surface to be machined on the ophthalmic device, at least according to optical power; providing at least one parameter representing the wear state of at least one location of a cutting edge of a cutting tool configured to machine the at least one desired surface of the ophthalmic device; determining a machining strategy based on both the at least one desired surface and the at least one parameter representing the wear state; the machining strategy being selected from at least one of a first instruction to machine the at least one desired surface with the cutting tool and a second instruction not to machine the at least one desired surface with the cutting tool, and the remote computer being configured to perform or not perform the machining according to the machining strategy.

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