MX2008001961A - Method of manufacturing an optical system - Google Patents

Abstract

The invention relates to a method of calculating an optical system (OS), the optical system (OS) being identified by a function (OF), the optical system (OS) comprising a first part (Fl) defined by a first equation (EFl) and a second part (F2) defined by a second equation (EF2), the method comprising:- a generating step (GEN), in which a virtual optical system (VOS) is used to generate a virtual function (VOF);- a modification step (MOD), in which the virtual function (VOF) is modified so as obtain the function (OF);- a calculation step (CAL), in which the second equation (EF2) is calculated from the function (OF), and the first equation (EFl). The invention relates also to a method of manufacturing an optical system (OS).

Description

METHOD TO MANUFACTURE AN OPTICAL SYSTEM Field of the Invention One aspect of the invention relates to a method for calculating and / or to a method for manufacturing an optical system, and more particularly to a lens with progressive magnification. Other aspects of the invention relate to a method for manufacturing a semi-finished optical system, a computer program product for calculating and / or for manufacturing an optical system, a computer program product for calculating and / or manufacturing a system semi-finished optical. BACKGROUND OF THE INVENTION Lenses with progressive magnification commonly comprise a region for far vision having a refractive power, a region for near vision having a different refractive power, and an intermediate progressive region. In accordance with a common practice, virgin semi-finished progressive lenses are provided by the lens manufacturer to laboratories with prescription. Generally, a semi-finished virgin progressive lens includes a progressive front surface and a spherical back surface ("standard semi-finished virgin lens"). A standard semi-finished virgin lens having appropriate optical characteristics is then selected based on a prescription. The rear spherical surface is finally machined and polished by the laboratory according to the prescription (based on the base curve), in order to obtain a sphero-toric surface that conforms to the prescription. Thus, a lens with progressive increase is obtained that complies with the prescription. BRIEF DESCRIPTION OF THE INVENTION According to one aspect, the invention relates to a method for calculating an optical system OS, the optical system OS is identified by an OF function, the optical system OS comprises a first part F1 defined by a first equation EF1 and a second part F2 defined by a second equation EF2, the method comprises: a generation step GEN, in which a VOS virtual optical system is used to generate a VOF virtual function; a modification step MOD, in which the VOF virtual function is modified in order to obtain the OF function; a CAL calculation step, in which the second equation EF2 is calculated from the OF function, and the first equation EF1. The optical system OS can be, for example, a lens with progressive magnification. The OF function can be, for example, an optical OF function. The first part and the second part can be, for example, any volume or surface of the optical system. The optical function OF of an optical system OS is defined as a function h of the opto-geometric properties of the optical system OS, which can be written, for a two-part system comprising a first part F 1 and a second part F2 , OF = h (EF1 (x, y, z) EF2 (x, y, z)) EF1 (x, y, z) defines the opto-geometric properties of the part F1. EF2 (x, y, z) defines the opto-geometric properties of the part F2 According to a feature of the invention, the virtual optical system VOS comprises a first virtual part VF1 defined by a first virtual equation EVF 1 and a second virtual part VF2 defined by a second virtual equation EVF2, the first virtual equation EVF1 and the second Virtual equation EVF2 define the VOF virtual function. According to one feature of the invention, the VOF virtual function is substantially equal to the VOF function. According to a feature of the invention, the generation step comprises selecting the first virtual equation EVF 1 in a database. According to a feature of the invention, the method further comprises a step of modifying the equation, in which the first virtual equation EVF1 is modified using a first modification function N 1, in order to obtain a first modified equation EVF1, the first equation EF1 is substantially equal to the first modified equation EVF '1. According to the previous feature, the first virtual part VF1 comprises a first volume of the VOS virtual optical system, the first equation depends on opto-geometric characteristics of the first volume, and wherein the first modification function N 1 modifies at least one of said opto-geometric characteristics. According to a previous characteristic, the opto-geometric characteristics comprise at least one characteristic chosen between the equation of a surface and the optical index of a volume.

According to another characteristic of the invention, the first virtual part VF1 is a first virtual surface and the second virtual part VF2 is a second virtual surface. According to the prior characteristic of the invention, the OF function depends on the difference of the equations of the first surface and the second surface, and where a second surface that modifies the function N2 is substantially equal to the first surface that modifies the function N 1. According to another feature of the invention, the OF function is an optical function OF. According to a feature of the invention, the OS optical system is a progressive magnification lens. According to another aspect, the invention relates to a method for manufacturing an optical system OS, the optical system OS is identified by an OF function, the optical system OS comprises a first part F1 defined by a first equation EF1 and a second part F2 defined by a second equation EF2, the method comprises: the generation step GEN, the modification step MOD, the calculation step CAL as previously described, in which the second equation EF2 is calculated from the OF function, and of the first equation EF1; providing a semi-finished MSFOS optical system with a semi-finished optical system SFOS including the first part F1; and a manufacturing step M2, in which the semi-finished optical system MSFOS is manufactured in such a way that it is provided with a second part F2 defined by the second equation EF2 and OS optical system is obtained according to a feature of the invention. According to another aspect, the invention relates to a method for manufacturing an optical system OS, the optical system OS is identified by an OF function, the optical system OS comprises a first part F1 defined by a first equation EF1 and a second part F2 defined by a second equation EF2, the method comprises: the generation step GEN, the modification step MOD, the calculation step CAL as previously described, in which the second equation EF2 is calculated from the OF function, and the first equation EF1; a first manufacturing step M 1 in which an SFOS semi-finished optical system comprising the first part is manufactured F1, in such a way as to obtain a semi-finished optical system manufactured by MSFOS; and - a second manufacturing step M2, in which the semi-finished optical system manufactured by MSFOS is manufactured in such a way that it is further provided with a second part F2 defined by the second equation EF2 and the optical system OS is obtained. According to the invention, the first manufacturing step M 1 defines the opto-geometric characteristics EF 1 (x, y, z) of the first part F1 of the semi-finished optical system. Thus, by choosing an appropriate second part F2, the invention allows the fabrication of an optical system such that OF = h (EF1 (x, y, z), EF2 (x, y, z)). In other words, if a semi-finished optical system was manufactured according to the first manufacturing step M 1, and was first intended to be modified to manufacture a first optical system OS 1 with an optical function OF1, the semi-optical system The termination can advantageously be used to manufacture a second optical system OS2, which has a second optical function OF2. With respect to this, the second equation EF2 only has to be chosen in such a way that OF2 = h (EF1 (x, y, z), EF2 (x, y, z)) and not OF1 = h (EF1 (x, y , z), EF2 (x, y, z)). Thus, the optical system does not depend on the characteristics of the semi-finished optical system only. This allows the manufacturer to store the semi-finished optical system independently of the optical system. Thus, the invention makes it possible to improve inventory management in a manufacturing process. According to a feature of the invention, the second manufacturing step M2 comprises the following sub-steps: a second modification step MS2, in which the second virtual equation EVF2 is modified using a second modification function N2 in such a way as to obtaining a second modified equation EVF2, the first modification function N1 and the second modification function N2 are defined in such a way that the optical system can be identified by the OF function, and a second manufacturing step MAN2, in which fabricates the second part F2 of the semi-finished optical system SFOS in such a way as to obtain the optical system OS, the second equation EF2 of the second part F2 is substantially equal to the second modified equation EVF2. According to the previous characteristic, the second virtual part VF2 comprises a second volume of the virtual optical system VIS, the second equation depends on the opto-geometric characteristics of the second volume, and wherein the second modification function N2 modifies at least one of said opto-geometric characteristics. According to another aspect, the invention relates to a method for manufacturing an optical system OS, the optical system OS is identified by an OF function, the optical system OS comprises a first part F1 defined by a first equation EF1 and a second part F2 defined by a second equation EF2, the method comprises: - the generation step GEN, the modification step MOD, the calculation step CAL as previously described, in which the second equation EF2 is calculated from the OF function , and the first equation EF1; a first manufacturing step M 1 in which an SFOS semi-finished optical system comprising the first part F2 is manufactured, in order to obtain a semi-finished optical system manufactured by MSFOS; and a second manufacturing step M2, in which the semi-finished optical system manufactured by MSFOS is manufactured in such a way that it is further provided with a second part F1 defined by the first equation EF1 and the OS optical system is obtained. For the purpose of the present application, the term "virtual" is used to define an optical system that is calculated and generated by computer. In accordance with the present invention, the virtual optical system is not intended to be manufactured as such. By generating a virtual optical system and defining the optical function as a modification of a virtual optical function, one can ensure that the CAL calculation step according to the invention has a solution. For example, if the optical function OF is substantially equal to the virtual optical function VOF, and the first equation EF1 is substantially equal to the first virtual equation, the second virtual equation EVF2 is a physical solution for the second equation EF2. The virtual optical function, for example, can be modified using the prescription data provided by a practitioner in eye care. Thus, by modifying this virtual function, the optical function can be more adapted to the characteristics of the eye. Moreover, by defining the optical function from the modification of a virtual optical function, memory space is saved. In fact, instead of storing the optical functions for each specific client, the method according to the invention allows a generic virtual function to be stored and modified by a specific modification. According to another aspect, the generation step according to the invention comprises selecting the first virtual equation EVF1 in a database. By selecting the first virtual equation in a database of known virtual equations, one can ensure that the performances of the optical system can be those of an existing system. Furthermore, by avoiding the calculation of a first specific equation and by selecting the equation in a database, calculation time is saved. According to another aspect of the invention, the method further comprises a step of modifying an equation in which the first virtual equation EVF1 is modified by using a first modifying function N1 so to obtain a first modified equation EVF1, the first equation EF1 is substantially equal to the first modified equation EVF '1.

The first modification function N 1, for example, can be arranged to place the opto-geometric characteristics of the first virtual part VF1 in such a way that: OF = h (N1 (VF1 (x, y, z)), EF2 ( x, y, z)) By providing a semi-finished standard optical system to prescription laboratories, it is very easy to obtain data that could be considered by the lens manufacturers as secret data. This can be achieved, for example, by using three-dimensional measurement systems. The secret data may be, for example, data relating to the geometry of the progressive face of the semi-finished virgin lens. The secret data can also be, for example, any opto-geometric characteristics, in particular the equations of the surfaces defined by the two parts of the optical index of the two parts, or any combination thereof. Using the first modification function in order to modify the first part of a VOS virtual optical system in order to manufacture a semi-finished optical system and a system having the required optical function, the secret data is divided between the first and the second part of the optical system. Therefore, it is more difficult to deduce the secret data using a measurement system. The invention also relates to a computer program product for a data processing device, the computer program product includes a set of instructions, which, when loaded into the data processing device, make the device perform the steps of the method according to the invention, for an optical system, or for a semi-finished optical system. BRIEF DESCRIPTION OF THE DRAWINGS The subject matter of this invention is particularly pointed out and clearly claimed in the concluding part of the specification. The invention, however, both as an organization and method of operation, together with its objects, features and advantages, can be better understood by reference to the following detailed description when read with the accompanying drawings, in which: A shows a graphic representation of an array of increases; Figure 1 B shows a graphic representation of an astigmatism arrangement; Figure 1 C shows an example of data that is used to determine the optical function of an optical system; Figure 1 D shows the longitude and latitude data used to represent the magnification arrangement and the astigmatism arrangement; Figure 2 is a block diagram of the manufacturing process according to the invention; Figure 3 is a block diagram of one embodiment of the manufacturing process according to the invention; Figure 4A schematically illustrates a virtual system generated in accordance with the present invention; Figure 4B schematically illustrates a modified virtual system in accordance with the present invention; Figure 5A schematically illustrates a virtual system generated in accordance with the present invention; Figure 5B schematically illustrates a semi-finished optical system manufactured in accordance with the present invention; Figure 5C schematically illustrates an optical system manufactured in accordance with the present invention; Figure 6A corresponds to a semi-finished optical system like that of Figure 5B. Figure 6B illustrates an optical system manufactured in accordance with the present invention, wherein the optical index has been modified to fulfill the optical function. DETAILED DESCRIPTION OF THE INVENTION Unless otherwise stated, as is evident from the following discussions, it will be noted that throughout the specification descriptions using terms such as "compute", "calculate", "generate" or the like , refer to the action and / or processes of a computer or computer system, or similar electronic computing device, that manipulate and / or transform data represented as physical quantities, for example, electronic, within the registers and / or memories of the computer system in other data similarly represented as physical quantities within the memories of the computer system, registers or other storage devices, transmission or presentation of information. The embodiments of the present invention may include apparatuses for performing the operations indicated herein. This apparatus may be specially constructed for the desired purposes, or it may comprise a general-purpose computer or Digital Signal Processor ("DSP") selectively activated or reconfigured by a computer program stored in the computer. This computer program can be stored in a computer-readable storage medium, for example, without limitation, any type of disk, including floppy disks, optical discs, CD-ROMs, magnetic optical discs, read-only memories (ROM). ), random access memories (RAM), electrically programmable read-only memories (EPROM), programmable read-only and electrically erasable memories (EEPROM), magnetic or optical cards, or any other type of appropriate means for storing electronic instructions, and capable of being coupled to a computer system bus. The processes and screens presented here are not inherently related to any particular computer or device. Various general purpose systems can be used with programs in accordance with the teachings presented herein, or it may be convenient to build a more specialized apparatus to perform the desired method. The desired structure for a variety of these systems will become apparent from the description presented below. In addition, the embodiments of the present invention are not described with reference to any particular programming language. It should be noted that a variety of programming languages can be used to implement the teachings of the inventions described here. The optical function OF of an OS optical system can be defined as follows: (1) OF (x, y, z) = MAT (x, y, z) + PRES; or (2) OF (x, y, z) = MAT (PU I (x, y, z); AST (x, y, z)) + PRES; or (3) OF (x, y, z) = H (F 1 (x, y, z); F2 (x, y, z); n (x, y, z))) MAT being an increase matrix and astigmatism; PU being an increase matrix; I feel AST a matrix of astigmatism; PRES prescribing data; F1 and F2 being the equation of the first face and the second face of the optical system; and Being n the optical index. It should be noted that if the optical index is a constant, the optical function OF of an optical system can be defined as follows: (4) OF (x, y, z) = h (F1 (x, y, z); F2 (x, y, z)) An example of graphical representation of a PU increase matrix and an AST astigmatism matrix is shown in Figure 1 A and Figure 1 B. These matrices (PUl, AST), have been obtained for an appropriate design for a user with addition of emmetropia 2. Illustrated in figure 1 D, the direction of the gaze is defined by two angles, from latitude to longitude ß, from the center of rotation of the eye. The aberrations are calculated for each gaze direction, to obtain a MAT matrix and a PU l matrix. PRES prescribing data are known to a person skilled in the art, and are related to usual data provided by an ophthalmic care practitioner, such as sphere, cylinder, shaft, prism, magnification addition. Additional data provided by an optometrist can be used if they are available. Advantageously, but without being limited to them, in the ophthalmic field the optical function can be obtained by adding the prescribed values of magnification and astigmatism to specific matrices, respectively PU l and AST. In general, these specific matrices can be given, for example, for each type of addition and ametropia (myopia, hyperopia, emmetropia). In order to better understand the invention, a method for manufacturing an OS optical system in the form of a lens with progressive magnification in detail will now be described. In this particular example, the optical index can be chosen as a constant. The optical function of an optical system can then be defined as follows: (5) OF = H (F1 (x, y), F2 (x, y)) As illustrated in Fig. 2, the method for manufacturing a lens with progressive increase OS comprises the manufacturing step M 1 in which a semi-finished optical system comprising a first part F1 is manufactured. The first part F1 is defined by a first equation EF1, which for example is the equation of an outer surface. Thus, a semi-finished optical system MSFOS manufactured is obtained. According to the invention, the equation of the second part EF2 is then determined in a calculation step CAL from the optical function and the equation of the first part EF1. Equations (5) and (4) are used to determine this equation from the optical function OF and the equation of the first surface EF1. The CAL calculation step can be performed using a trajectory method or optimization algorithms. These methods are known to a person skilled in the art, for example in the publication "Application of optimization in computer-aided ophthalmic lens design" (P. Allione, F. Ahsbhs and G. Le Saux, in SPI E Vol 3737, Conference on design and engineering of optical systems EUROPTO, Berlin, May 1 999), which is incorporated by reference in this document. In a second manufacturing step M2, the semi-finished optical system manufactured by MSFOS is manufactured in such a way as to obtain a second part of the equation EF2. This can be done by any method known in the lens manufacturing art as described, for example, in the US patent issued under grant number US 6,558,586 B 1, the content of which is incorporated herein by reference. The semi-finished optical system manufactured by MSFOS further provided with a second part F2 of the equation EF2 forms the OS optical system. In a particular modality, the optical function OF of the OS optical system to be manufactured is based on a VOF virtual optical function. In a virtual optical system that generates the GEN step, a VOS virtual progressive magnification lens having a VOF virtual optical function is generated. As illustrated in Figures 4A and 4B, the VOS virtual progressive magnification lens comprises a first virtual face VF 1 that is defined by a first equation EVF1. The lens with virtual progressive magnification VOS further comprises a second virtual face VF2 which is returned by a second equation EVF2. The VOF virtual optical function can then be modified in a modification step MOD to obtain an optical function F. The modified virtual optical system MVOS has a modified first face MVF1 and a modified second face MVF2. MOD modification can be done using prescription data from an ophthalmic care practitioner to be adapted to the prescription.

Modification MOD can be without limitation an isometric transformation such as compensation, symmetry, translation or a transformation of the VOS virtual optical system. If the modification is chosen as the identity function, the modified virtual optical system is the virtual optical system, and the optical function is substantially equal to the virtual optical function. A VOF pre-established virtual optical function can then be retrieved directly from a database to define the opto-geometric characteristics of the virtual optical system. Modification step MOD can then be used to adapt this VOF virtual optical function to the needs of a particular user. For example, if the database containing the virtual optical function is available, one can choose, between the database, a virtual optical function that corresponds to the general characteristics of the user. A more precise adaptation of this virtual optical function is then carried out in a modification step MOD to adapt the OS optical system to the most precise needs of the user. As illustrated in Figure 3, according to another aspect, the method for manufacturing a lens with progressive magnification OS comprises a first manufacturing step M 1 and a second manufacturing step M 2. It also comprises a step of generating the virtual optical system GEN and a first step of modification MS 1. In the step of generating the virtual optical system GEN, a lens with virtual progressive magnification VOS is generated, which has a virtual optical function VOF. As illustrated in FIG. 5A, the VOS virtual progressive magnification lens comprises a first virtual face VF1 that is defined by a first equation EVF1. The lens with virtual progressive magnification further comprises a second virtual face VF2 which is defined by a second equation EVF2. The first equation EVF1 and the second equation EVF2 are chosen in such a way that: VF (x, y, z) = vh (EVF 1 (x, y, z), EVF2 (x, y, z)) EVF1 (x, y) and EVF2 (x, y) can be defined, for example, in such a way that the optical function VF of the lens with virtual progressive magnification VOS is substantially equal to the optical function OF of the lens with progressive magnification OS. As illustrated in Figure 3, in a first modification step MS1, the first equation EVF1 (x, y) is modified, for example, by adding a first coding function N 1 (x, y), so as to obtain a modified equation EVF1 defined as follows: EV'F1 (x, y) = EVF 1 (x, y) + N 1 (x, y) Then, in a first manufacturing step M 1, a first surface F1 of an SFOS semi-finished optical system. The equation EF1 of the first surface F1 is defined as follows: EF1 (x, y) = EV'F1 (x, y) Thus, a semi-finished optical system is obtained. The fabrication of the SFOS semi-finished optical system can be done by any method known in the lens manufacturing art as described, for example, in the US patent issued under the title number US 6,558,586 B 1, the content of which is incorporated herein by reference. It should be noted that the first coding function N 1 (x, y) is a secret data that is only known to a person who is implementing the manufacturing method of the invention. The first coding function N 1 can be more generally any secret transformation of the function EVF1 (x, y), such that EF1 (x, y) = N 1 [EVF1 (x, y)] Thus, when analyzing the system Semi-finished optical SFOS, it will be more difficult for a third party to access secret data EVF1 (x, y) and EVF2 (x, y). As illustrated in Figure 3, the method for manufacturing a lens with progressive magnification further comprises a second manufacturing step M2. The second manufacturing step M2 comprises a second modification sub-step MS2 and a second manufacturing sub-step MAN2. In the second modification sub-step MS2, the second equation EVF2 (x, y) is modified, for example, adding a second coding function N2 (x, y), in order to obtain a second modified equation EV'F2 (x, y) defined as follows: EV'F2 (x, y) = EVF2 (x, y) + N2 (x, y) The second coding function N2 (x, y) is chosen in such a way that OF (xy) = h (N 1 [EVF1 (x, y)], N2 [EVF2 (x, y) ]) It should be understood that other restrictions may be added in the selection of the first and second coding functions N 1 and N2. These restrictions may be linked, for example, to calculation time or other restrictions defined by manufacturing laboratories. Then in a second manufacturing sub-step MAN2, a second face F2 of the semi-finished optical system is manufactured SFOS in order to obtain the lens with progressive OS increase. The surface of the second face F2 of the lens with progressive magnification OS is defined by the second modified equation EV 'F2 (x, y). It is understood that the first and second faces F1, F2 of the lens with progressive magnification OS must comply with the constraints defined by the optical function OF. When the optical function is a function of the difference of the surface equations, that is, OF = h (EF2 (x, y) - EF1 (x, y)), the second preferred coding function N2 (x, y ), is substantially equal to N 1 (x, y). According to an advantage of the invention, the first coding function and the second coding function N 1 and N 2 only depend on the optical system OS being manufactured. A semi-finished optical system SFOS provided with a first face F1 with equation EF1 (x, y) = N 1 [EVF1 (x, y)] can then be used, for example, to manufacture an OS 1 optical system having a optical function OF1. But the same SFOS semi-finished optical system could also be used to manufacture an OS2 optical system having an OF2 optical function. In this case, the second coding function N2 has to be chosen in such a way that OF2 (x, y) = h (N 1 (EVF1 (x, y)), N2 (EVF2 (x, y)). SFOS semi-finished optical systems inventory can then be done by associating the SFOS semi-finished optical systems with the optical system to be manufactured.Alternatively, SFOS semi-finished optical systems inventory management can be done independently of the optical system Finally, by choosing appropriate modification functions, inventory management in the manufacturing process therefore improves.The detailed description above with reference to the drawings illustrates a method for manufacturing an optical system OS, the optical system OS is identified by a function OF, the optical system OS comprises a first part F1 defined by a first equation EF1 and a second part F2 defined by a second equation EF2, the method comprising: a step of c calculation CAL, in which the second equation EF2 is the calculated from the function OF, and the first equation EF1; - a first manufacturing step M 1, in which a semi-finished optical system SFOS is manufactured, which comprises the first part F1 in such a way as to obtain a semi-finished optical system manufactured by MSFOS; and a second manufacturing step M2, in which the semi-finished optical system MSFOS is manufactured in such a way that it is further provided with a second part F2 defined by the second equation EF2 and the OS optical system is obtained. The characteristics mentioned above can be be implemented in numerous different ways. In order to illustrate this, some alternatives are briefly indicated. The first part and the second part can correspond to any volume or surface of the optical system. The first part and the second part can be, for example, a first face and a second face of the optical system corresponding to the front and rear optical surfaces, or a first volume and a second volume of the optical system corresponding to a rear part and a front of the system. The opto-geometric characteristics can be, for example, the equations of the surfaces that define the two parts, or the optical index of the two parts, or any combination of them. The calculation of the second equation EF2 from the function OF, and from the first equation EF1 in the calculation step CAL can be carried out by any algorithm known in the technique of calculation of optical systems. The detailed description presented here with reference to the drawings also illustrates a method that also comprises the following steps: a GEN generation step, in which a VOS virtual optical system is used to generate a virtual VOF function, the virtual optical system VOS comprises a first virtual part VF1 defined by a first virtual equation EVF1 and a second virtual part VF2 defined by a second virtual equation EVF2, the first virtual equation EVF1 and the second virtual equation EVF2 define the virtual function VOF; a modification step MOD, in which the VOF virtual function is modified in such a way as to obtain the OF function. Modification MOD can be without limitation an isometric transformation, such as compensation, symmetry, translation, or a metamorphosis of the VOS virtual optical system. The detailed description presented here with reference to the drawings also illustrates a method that further comprises a modification step of the equation, in which the first virtual equation EVF1 is modified using a first modification function N 1 in such a way that a modified first equation EVF1 is obtained, the first equation EF1 is substantially equal to the first modified equation EVF'1. The first modification function N 1, for example, can be a coding function or a noise function. The noise function can be any discontinuous function, such as, for example, a diffractive function, in particular, a Fresnel function. Advantageously, the discontinuous function has a spatial frequency cut that is preferably less than 1 mm-1 (1/1 millimeter). The noise function can be, for example, a white noise function. More generally, the first function N 1 can be any function arranged to modify the opto-geometric characteristics of the parts or surfaces of an optical system. The detailed description also illustrates a method for manufacturing an OS optical system, wherein the second manufacturing step M2 comprises the following sub-steps: a second modification step MS2, in which the second virtual equation EVF2 is modified using a second modification function N2 in order to obtain a second modified equation EVF2, the first modification function N1 and the second modification function N2 are defined in such a way that the optical system can be identified by the OF function, and a second step of manufacture MAN2, in which the second part F2 of the semi-finished optical system SFOS is manufactured, so as to obtain the optical system OS, the second equation EF2 of the second part F2 is substantially equal to the second modified equation EVF2. The second modification function N2 can be, for example, a coding function or a noise function, in particular, a white noise function. The functions described here have been provided in Cartesian coordinates (x, y, z), but it is understood that any coordinate in the method according to the invention can be used. In the detailed description, the equations of the surfaces of the systems have been modified. It must be understood that any other opto-geometric characteristics can be modified.

As illustrated in Figures 6A and 6B, the second modification function N2 can be a modification of the optical index n2 (x, y, z), in a part P2 of the semi-finished optical system. This modification is indicated by dotted lines in Figure 4B. Therefore, N2 has to be chosen in such a way that OF1 = h (N1 (EVF1 (x, y), N2 (P2 (x, y, z)) You can also choose any modification in the opto- of the optical system function, whether in surface characteristics or in volume characteristics, provided that it respects the optical function OF or a specific part of the optical function OF of the optical system, moreover, in the previous examples, function F was an optical function OF But the function F can also be a part of this optical function OF For example, for a given optical system that has an optical function OF given by the equation OF (x, y, z) = MAT (x, y, z) + PRES, the function F can be defined by the matrix of increase and astigmatism MAT.In this case, the functions of modification N 1 and N2 are such that MAT = g (EVF 1, EVF2), and MAT = g ( N 1 (EVF1), N2 (EVF2)) More generally, function F can be any function arranged to identify or define an optical system. or OS Other examples are provided to illustrate the present invention with detailed and concrete cases, without limitation to other specific applications. Example 1 Example 1 refers to the variation of the index of the material of a lens. eleven . Defining the VOS virtual optical system The VOS is a progressive lens with a progressive front surface and a spherical support surface, such as a VARILUX COM FORT® lens from ESSI LOR Company (for example, with a diopter 0 far vision correction). ), for example a VARI LUX COM FORT® Base 5.50 with an increase of 2 diopters, where the lens material consists of ORMA® (refractive index = 1 .5). The respective position of the front and rear surfaces is such that the thickness of the lens is as small as possible, and where the thickness at its center is more than 1 mm and the thickness of its edge is more than 0.3 mm. The prism between the two surfaces has to compensate for differences in thickness between the far vision zone and the near vision zone due to the magnification, or it has to be appropriate to obtain a given prismatic prescription. 1 .2. Building the VOF virtual optical function: A VV virtual viewer has a prescription with an increase of 2 diopters, with a cylindrical correction of 0 diopters and a sphere correction of 0 diopters. The magnification and astigmatism are calculated for a set of gaze directions (a, b,) for the "lens" + "eye" system in the given environment. For this OS optical system, the virtual optical function is: VOF (OS) = Sum [weight_st (i) (AST (al, bl lOS) AST (al, b ,, VOS)) 2 + weight_pu (i) (PU) I (a "b ,, OS) -PU I (a" bl, VOS)) 2], where: Sum is the sum in the index i; AST (a, b, v) is the astigmatism of the optical system v for the direction of the gaze (a, b); PUI (a, b, v) is the energy for the gaze direction (a, b) of the optical system v. Following the invention, the OS lens of the RV real viewer has to be as close as possible including the RV prescription. Then MOD modification is applied. 1 .3 Modification of the virtual optical function VOF: MOD (VOR (OS)) = Sum [weight_ast (i) (ASR (ai, b, OS, Sph> Cil, Axis) -AST (ai, b¡, VOS)) 2 + weight_pui (i) ((PUI (a¡, b,, OS) -Sph) -PU I (a¡, b¡, VOS)) 2] I Where: ASR (a, b, v, Sph, Cil, Axis) is the resultant astigmatism of the OS lens, for the actual RW viewer, and when considering its spherical prescription, Sph, its indic cyl prescription, Cil, its axial prescription axis. Therefore, it is the vector difference between the OS lens and the astigmatism of the RV real viewer. 1 .4 Definition of the OS lens The characteristics of the OS are, for example: progressive front surface VARI LUX COM FORT® base 5.5. with addition of 2.0 diopters; rear surface to be determined in the CAL step; - refractive index of the material = 1 .8; lens thickness as low as possible and where the thickness of the center is more than 1 mm, and the thickness of the edge is more than 0.3 mm; the prism between the two surfaces has to compensate for the difference in thickness between the far vision zone and the near vision zone due to an increase, or it is appropriate to obtain a given prismatic prescription. The front surface can be the same as that of the VOS. The modification due to the modification of the refractive index will then appear on the back surface. The front surface may be different from that of the VOS, and may be adapted to the current refractive index. Said front surface will be calculated accordingly. The first part F1 consists of: front surface; - lens material; relative position of the front and rear surfaces. The second part F2 consists of: rear surface The first equation EF1 consists of: - front surface equation refractive index; 4 x 4 matrix of position changes between the front and rear surfaces. The second equation EF2 consists of: - equation of the back surface.

The equations of the front and back surfaces can be expressed for example using two-dimensional polynomial functions, such as Zernike polynomials, functions with B splines, N URBS functions. 1 .5 Calculation step CAL The parameters of the rear surface are determined to minimize MOD (VOF (OS)). The curvature parameters can be forced, for example in some regions of the far vision zone or the near vision zone. Example 1 shows that in this way it is possible to manufacture an optical OS system from a virtual optical system VOS, the optical system OS has substantially the same optical properties as those of the virtual optical system VOS, but with a different refractive index. Example 2 Example 2 refers to a design modification of the progressive surface of a lens. 2.1. Definition of the virtual optical system The characteristics are for example: progressive front surface, with its design, for example VARI LUX COM FORT® base 5.5. with addition of 2.0 diopters; spherical rear surface with correction for far vision of 0 diopters; ORMA® material (the refractive index is 1.5) the respective position of the front and rear surfaces is such that the thickness of the lens is as small as possible, and where the thickness at its center is more than 1 mm and the thickness at its edge is more than 0.3 mm. The prism between the two surfaces has to compensate for differences in thickness between the far vision zone and the near vision zone due to addition, or it is appropriate to obtain a given prismatic prescription. 2.3. Construction of the virtual optical function VOF The virtual viewer, for example, was a prescription where: Sph = 0 diopters Cil = 0 diopters Increase = 2.0 diopters and the same virtual optical function VOF as above 1 .2. 2.3. Modification of the virtual optics of the VOF function: The same step as previously in accordance with 1 .3 2.4 Definition of the OS lens - progressive front surface with another design than the virtual one, such as for example VARILUX® PANAM IC® base 5.50 of the company ESSI LOR, with an increase of 2.0 diopters; rear surface to be determined in the CAL step; refractive index = 1 .5 (ORMA® material) - lens thickness as small as possible and where the thickness of the center is more than 1 mm, and the thickness of the edge is more than 0.3 mm, the prism between the Two surfaces have to compensate for the difference in thickness between the far vision zone and the near vision zone due to an addition, or it is appropriate to obtain a given prismatic prescription: The first part F 1 consists of: front surface; lens material; relative position of the front and rear surfaces The second part F2 consists of: rear surface. The first equation EF1 consists of: equation of the front surface; refractive index; - 4 x 4 matrix of position changes between the front and rear surfaces. The second equation EF2 consists of; Equation of the rear surface. The equation of the front and back surface can be expressed for example using two-dimensional polynomial functions, such as the Zernike polynomials, functions with B splines, N URBS functions. 2.5. Calculation step CAL The same step as previously according to 1 .5. Example 2 shows that it is thus possible to manufacture an optical system OS having a particular design, from a semi-finished optical system SFOS comprising a part F1 having a different design, the optical system OS has substantially the same optical properties than those of the VOS virtual optical system. In the aforementioned description, the OS optical system was a progressive magnifying lens. It should be understood that it can also be any type of optical system, for example a lens or a multifocal lens. The optical system can also be any device either to concentrate or to diverge light. The optical system can also be any analogous device used with other types of electromagnetic radiation, such as a microwave lens, for example made of paraffin wax. The optical system can also be part of an imaging system such as a monocle, binoculars, a telescope, a terrestrial telescope, a telescopic scope for a weapon, a microscope, and a camera (photographic lens). The optical system can also be a dielectric lens for radio astronomy and radar systems to refract electromagnetic radiation in a collector antenna. The comments made here above demonstrate that the detailed description with reference to the drawings, illustrate rather than limit the invention. There are numerous alternatives, which fall within the scope of the appended claims. Any sign of reference in a claim should not be interpreted as a limitation of the claim. The word "comprises" does not exclude the presence of other elements or steps other than those listed in a claim. The words "a", "an" or "an", preceding an element or step do not exclude the presence of a plurality of said elements or steps.

Claims (18)

1. A method for calculating an optical system (OS), the optical system (OS) is identified by a function (OF), the optical system (OS) comprises a first part (F1) defined by a first equation (EF1), EF1 ( x, y, z) defines the opto-geometric properties of the part F1, and a second part (F2) defined by a second equation (EF2), EF2 (x, y, z) defines the opto-geometric properties of the part F2, where the first part (F1) and the second part (F2) are a volume or surface of the optical system, the method comprises: a generation step (GEN), in which a virtual optical system (VOS) is used to generate a virtual function (VOF); a modification step (MOD), in which the virtual function (VOF) is modified in order to obtain the function (OF); a calculation step (CAL), in which the second equation (EF2) is calculated from the function (OF), and from the first equation (EF1). and wherein the optical function OF of an optical system OS is defined as a function h of the opto-geometric properties of the optical system, where OF = h (EF1 (x, y, z), EF2 (x, y, z )).

2. The method for calculating an optical system (OS) according to claim 1, further characterized in that the virtual optical system (VOS) comprises a first virtual part (VF1) defined by a first virtual equation (EVF1) and a second part virtual (VF2) defined by a second virtual equation (EFV2), the first virtual equation (EVF 1) and the second virtual equation (EVF2) define the virtual function (VOF).

3. The method for calculating an optical system (OS) according to claims 1 or 2, further characterized in that the virtual function (VOF) is substantially equal to the function (OF).

4. The method for calculating an optical system (OS), according to claims 1 to 3, further characterized in that the generation step comprises selecting the first virtual equation (EVF 1) in a database.

5. The method for calculating an optical system (OS) according to any of claims 1 to 4, further characterized in that the method further comprises a step of modifying the equation, in which the first virtual equation (EVF 1) is modified using a first modification function (N 1) in order to obtain a first modified equation (EV F 1), the first equation (EF 1) is substantially equal to the first modified equation (EVF '1).

6. The method according to claim 5, further characterized in that the first virtual part (VF 1) comprises a first volume of the virtual optical system (VOS), the first equation depends on the opto-geometric characteristics of the first volume, and further characterized in that the first modification function (N 1) modifies at least one of said opto-geometric characteristics.

7. The method according to claim 6, further characterized in that the opto-geometric features comprise at least one characteristic chosen between the equation of a surface and the optical index of a volume. The method according to claim 2, further characterized in that the first virtual part (VF 1) is a first virtual surface and the second virtual part (VF2) is a second virtual surface. 9. The method according to claims 8 and 5, further characterized in that the function (OF) depends on the difference of the equations of the first surface and the second surface, and further characterized by a second surface modification function (N2) is substantially equal to the first surface modification function (N1). The method according to any of the preceding claims, further characterized in that the function (OF) is an optical function (OF). eleven . The method according to any of the preceding claims, further characterized in that the optical system (OS) is a lens with progressive magnification. 1 2. A method for manufacturing an optical system (OS), the optical system (OS) is identified by a function (OF), the optical system (OS) comprises a first part (F 1) defined by a first equation (EF 1) and a second part (F2) defined by a second equation (EF2), the method comprises: the generation step (GEN), the modification step (MOD), the calculation step (CAL) according to any of claims 1 to 11, in which the second equation ( EF2) is calculated from the function (OF), and from the first equation (EF1); - providing a semi-finished optical system (MSFOS) with a semi-finished optical system (SFOS) comprising the first part (F1); and a manufacturing step (M2), in which the semi-finished optical system (MSFOS) is manufactured in such a way that it is further provided with a second part (F2) defined by the second equation (EF2) and the system is obtained optical (OS). 13. A method for manufacturing an optical system (OS), the optical system (OS) is identified by a function (OF), the optical system (OS) comprises a first part (F1) defined by a first equation (EF1) and a second part (F2) defined by a second equation (EF2), the method comprising: the generation step (GEN), the modification step (MOD), the calculation step (CAL) according to any of the claims 1 up to 11, in which the second equation (EF2) is calculated from the function (OF), and from the first equation (EF1); a first manufacturing step (M1), in which the semi-finished optical system (SFOS) comprising the first part (F1) is manufactured, in such a way that a semi-finished optical system (MSFOS) is obtained; and - a second manufacturing step (M2), in which the semi-finished optical system (MS FOS) is manufactured in such a way that it is further provided with a second part (F2) defined by the second equation (EF2) and Obtain the optical system (OS). 1 4. A method according to claim 1 2 or 1 3, and including the calculation according to claim 5, further characterized in that the second manufacturing step (M2) comprises the following sub-steps: a second step of modification (MS2), in which the second virtual equation EVF2 is modified using a second modification function (N2) in such a way as to obtain a second modified equation EV F2, the first modification function (N1) and the second function modification (N2) are defined in such a way that the optical system can be identified by the function (OF), and a second manufacturing step (MAN2), in which the second part (F2) of the semi-optical system is manufactured. In order to obtain the optical system (OS), the second equation (E F2) of the second part (F2) is substantially equal to the second modified equation (EV F2). 5. A method according to claim 1, further characterized in that the second virtual part (VF2) comprises a second volume of the virtual optical system (VOS), the second equation depends on the opto-geometric characteristics of the second volume, and wherein the second modification function (N2) modifies at least one of said opto-geometric characteristics.

16. An optical system comprising two parts, the optical system (OS) that is identified by a function (OF), the optical system that is manufactured with a method according to claims 12 to 15. 17. A semi-finished optical system (MSFOS) manufactured in accordance with the first manufacturing step (M1) of claim 13 and directed to be modified by the second manufacturing step (M2) of claim 13 to 15. 18. A method for manufacturing an optical system ( OS), the optical system (OS) is identified by a function (OF), the optical system (OS) comprises a first part (F1) defined by a first equation (EF1) and a second part (F2) defined by a second equation (EF2), the method comprises: the generation step (GEN), the modification step (MOD), the calculation step (CAL) according to any of claims 1 to 11, in which the second equation ( EF2) is calculated from the function (OF), and from the first equation (EF1); a first manufacturing step (M1), in which a semi-finished optical system (SFOS) is made, comprising the first part (F2), in such a way that a semi-finished optical system (MSFOS) manufactured is obtained; and a second manufacturing step (M2), in which the semi-finished optical system (MSFOS) is manufactured in such a way that it is further provided with a first part (F1) defined by the first equation (EF1) and the optical system (OS). 1 9. A computer program product for a data processing device, the computer program product comprises a series of instructions which, when loaded into the data processing device, causes the device to perform at least one of the steps of the method claimed in claims 1 to 1

8. SUMMARY The invention relates to a method for calculating an optical system (OS), the optical system (OS) is identified by a function (OF), the optical system (OS) comprises a first part (F 1) defined by a first equation (EF 1) and a second part (F2) defined by a second equation (EF2), the method includes: - a generation step (GEN) in which a virtual optical system (VOS) is used to generate a virtual function ( VOF); - a modification step (MOD), in which the virtual function (VOF) is modified in such a way as to obtain the function (OF); - a calculation step (CAL), in which the second equation (EF2) is calculated from the function (OF) and the first equation (EF 1). The invention also relates to a method for manufacturing an optical system (OS).