Method for determining an optimal assembly of lenses in an optical objective

Abstract

The invention relates to a method for determining an arrangement of n real individual lenses Lri to form an optical objective, which method comprises the steps of: - determining the presence of at least one defect on each manufactured lens Lri,j, - for at least one combination of manufactured real individual lenses, each comprising at least one of the defects, determining, by means of a simulation model, a value of an angle of rotation, the axis of rotation whereof is the optical axis of the optical objective, of the at least one manufactured real lens Lri,j of the at least one combination of manufactured real individual lenses Lri,j, referred to as the optimal angle, for which an optical transfer function (FTO) of the at least one combination is at a maximum or is greater than a threshold value.

Description

[0001] DESCRIPTION

[0002] Method for determining an optimal assembly of lenses in an optical objective

[0003] Technical field

[0004] The present invention relates to the manufacture and assembly of lenses in an optical objective.

[0005] The invention relates to the pre-production and production, and in particular on a large scale and / or in large quantities, of lenses and the assembly of these lenses to form optical objectives.

[0006] As a specific non-limiting example, the targeted optical lenses are those of smartphones.

[0007] State of the prior art

[0008] The manufacturing of a specific optical lens includes a step of modeling the specific lens considered according to the desired properties and the intended use. An optical lens generally comprises between 4 and 10 individual lenses, each having determined optical and geometric properties arranged in a particular arrangement. After designing the model, it is necessary to develop a manufacturing process for the individual lenses constituting the optical lens. Finally, these lenses are assembled according to a given assembly and a particular arrangement, previously determined, to form the module of the optical lenses.These optical modules will then be assembled with charge-coupled device sensors, known as CCD sensors, or with metal-oxide semiconductor sensors, known as CMOS sensors, to form the camera module.

[0009] Typically, each individual lens in the previously modeled assembly is manufactured in batches of several lenses in a mold. The mold includes a set of cavities into each of which is poured a liquid material that will form an individual lens. An individual lens will therefore be manufactured by one of the cavities. The cavities and molds are manufactured so that each lens manufactured in each cavity of the same mold has the optical and geometric properties of one of the theoretical individual lenses in the lens assembly previously modeled to develop the particular optical objective. In practice, lenses from the same cavity therefore have a very similar form error but lenses manufactured in different cavities have different errors or defects related to the shape of the cavity and the thermal profile and injection pressure speed during the molding cycle.Thus, none of the lenses manufactured from the same batch perfectly matches the corresponding theoretical lens. Also, the individual lenses manufactured in the same mold have geometric and optical disparities between them and also have geometric and optical disparities compared to the theoretical individual lens of the previously modeled lens assembly. Thus, it is necessary to find and select the combination of individual lenses manufactured in each mold that allows to form an optical lens whose optical properties are closest to those expected. The cavities of the same mold can generally produce several lenses of the same type in parallel, or possibly several lenses of several types.

[0010] Current state-of-the-art lens assembly processes are performed empirically through successive trials and tests to find the best set of rotations of individual lenses manufactured from each mold. The lead times required by current state-of-the-art processes for the stages of developing the manufacturing process and manufacturing the lenses and the stage of assembling the lenses are typically 4 to 6 months.

[0011] An aim of the invention is to propose a method for determining the assembly of lenses allowing:

[0012] - to significantly reduce the time required to find the best combination of individual lenses manufactured to form the optical objective, and / or

[0013] - to methodically and / or systematically determine the best combination of individual lenses manufactured, and / or

[0014] - to improve the quality of the manufactured optical lens, i.e. to obtain an optical lens with the best optical properties or optical properties closest to the expected optical properties, and / or

[0015] - to improve the efficiency of the production line of the manufactured optical lens, and / or - to minimize the dispersion of quality between the optical lenses produced within the production line.

[0016] Presentation of the invention

[0017] For this purpose, a method is proposed for determining an arrangement of n real individual lenses Lri to form an optical lens. The real individual lenses Lri are intended to be assembled along an optical axis of the optical lens in accordance with a model. The model has been previously designed so that the optical lens has specific optical properties. The model or the optical lens consists of a particular succession of n theoretical individual lenses Lti, where i is the position of the lens in the optical lens and i is between 1 and n. Each real individual lens Lri is manufactured to have the optical and geometric properties of the corresponding theoretical individual lens Lti within the optical lens. Each real individual lens Lri is manufactured in batches of mi lenses in a manufacturing mold dedicated to the manufacture of the real individual lens Lri.The actual individual lenses manufactured are denoted Lri,j where j is the position of the lens in the mold and j is between 1 and mi.

[0018] The method comprises the step of, for each manufactured lens Lri,j or for at least some of the manufactured lenses Lri,j, determining, from a real geometry of at least one of the two faces of a manufactured lens Lri,j considered and from the theoretical geometry of at least one of the faces of the theoretical lens Lti corresponding to the manufactured lens considered, the presence of at least one of the following defects:

[0019] • a difference in geometric shape of the manufactured lens considered compared to the corresponding theoretical lens,

[0020] • a difference in the refractive index of the manufactured lens considered compared to the corresponding theoretical lens and / or a difference in the dependence of the refractive index on the wavelength,

[0021] • an offset of the position of the geometric center of the manufactured lens considered relative to the optical axis of the optical objective,

[0022] • an offset of the position of the optical center of the manufactured lens Lri,j relative to the optical axis of the optical objective, • an inclination of the manufactured lens considered relative to the optical axis,

[0023] • a difference between a thickness of the manufactured lens considered and a thickness of the corresponding theoretical lens,

[0024] • a difference between a spacing between the manufactured lens considered and the manufactured lens subsequent to the manufactured lens considered within the succession of lenses and a spacing between the theoretical lens corresponding to the manufactured lens considered and the theoretical lens subsequent to the corresponding theoretical lens within the succession of lenses.

[0025] The method further comprises the step of, for at least one combination of n individual real lenses manufactured, each comprising at least one of the defects, and for at least one real lens manufactured Lri,j of the at least one combination of individual real lenses manufactured, determining, by means of a simulation model, a value of a rotation angle, having as its rotation axis the optical axis of the optical objective, of the at least one real lens manufactured Lri,j of the at least one combination, called optimal angle, for which an optical transfer function (OTF) of the at least one combination, representative of the desired optical quality, is maximum or is greater than a threshold value.

[0026] Optical transfer function (OTF) is understood to mean, for example, an indication of the optical contrast ratio obtained at different points in the image sensor field, for one or more spatial frequencies, which is known as MTF (Modulation Transfer Function) in English, or Fonction de Modulation du Transfer (optique) in French.

[0027] FTO can also be understood as the Point Spread Function (PSF), which represents, for a given point in the observed scene, the light spot obtained at the image sensor.

[0028] Of course, evaluating these functions may require tuning the focus of the optical lens and the image sensor, by changing this distance, depending on the position of the plane of the observed scene, in order to obtain the maximum sharpness according to the focus.

[0029] In order to have the maximum optical quality, for the MTF, it is preferable to maximize the value of the function, therefore the contrast ratio which reveals the best sharpness of the image, globally over the entire image sensor, which mathematically translates into the calculation of an indicator representing a combination, for example a sum, possibly weighted according to the positions of the image sensor where it is evaluated, of the values ​​of the MTF (the MTF varying continuously in each position between 0 and 1 from the worst to the best optical quality).

[0030] If we take the FDP (or PSF), it is preferable to minimize, for example, the average radius of the PSFs obtained in a set of positions on the sensor, for different points observed on the scene, at the positions corresponding to these points. In the latter case, it is preferable to mathematically transform the radius, noted x, for example by the function 1 / x, in order to also obtain a value to maximize when the optical quality is better, that is to say the sharpness obtained is better or even a minimum radius of the PSF. We can also sum the contributions of the MTFs or PSFs for different wavelength bands according to the 3 colors Red, Green, Blue detected by the sensor, for example.

[0031] Thus, the FTOs relating the optical performances of each objective produced must be maximized simultaneously, by means of a combination law to be chosen to obtain such a result. We can add the FTOs of each objective to globally maximize their sum. We can also choose other criteria, such as a minimum to be reached on each FTO, in order to avoid obtaining objectives of too high performance to the detriment of others, of too low quality, to instead obtain a homogeneous quality on all the objectives. Thus, the choice of the way to combine the FTOs can guide the solution obtained towards a different global optimization. We therefore choose a way to combine the FTOs of the objectives between them, for example by considering the minimum of the set of FTOs, or for example by adding them, which gives an overall criterion to be reached.

[0032] Preferably, the geometry of a considered face of a lens is understood to mean the geometry of the external surface of the considered face of a lens. Preferably, the geometry of a lens is constituted by the two faces of a lens or, in other words, by the geometry of the external surface of a lens or by the geometry of the external surface of each of the two faces of a lens. The geometry of a lens is also distinguished by a part, called the optical part, and a part, called the mechanical part. The optical part of the lens constitutes the central portion of the lens with which the light beams penetrating the lens will interact and the mechanical part constitutes the annular part of the lens serving as a bearing surface on which fixing means will be engaged.When the presence of several defects, among the at least one defect, is determined on a given manufactured lens, not all of the determined defects are necessarily taken into account during the step of determining the optimal angle. Only one of the defects whose presence has been determined may be taken into account during the step of determining the optimal angle. However, preferably, all of the defects, among the at least one defect, determined on a given manufactured lens are taken into account during the step of determining the optimal angle.

[0033] The number of lenses produced may vary from batch to batch depending on the type, denoted Li, of the lens produced. Also, preferably, in this case, the number of lenses per batch is denoted mi, where mi is the number of molding cavities of lenses Li of the same type in parallel. Preferably, each position j in the mold corresponds to a mold cavity in which an actual lens Lri,j. is manufactured. Each cavity of the same batch may provide lenses of the same type whose defects to be minimized are different.

[0034] Preferably, each mold comprises the same number mi of cavities.

[0035] Each type of lens Li is produced in parallel, half times, by half cavities of the same mold dedicated to the manufacture of a type of lens Li. From these sets of half lenses for each type of lens Li, if for example the mi of each type of lens Li are equal to a common value m, up to m lenses can be produced from the lenses manufactured, in a single run, in the same mold. Thus, a first association of n lenses produces a first objective, by selecting a lens from the mi of each type of lens Li, the association which produces the best result, and by choosing the best combination of manufactured lenses Lri,j. In addition, the manufactured lenses not used during this first association can themselves be combined to form a second optical objective, and so on, until using, if possible, all the half cavities of each mold.

[0036] Preferably, it can be understood by a succession, or particular or specific succession, of n theoretical individual optical lenses Lti, an assembly, or particular or specific assembly, of n theoretical individual optical lenses Lti. According to the invention, it can be understood by succession, particular succession or specific succession of lenses, an assembly, a particular assembly or a specific assembly, of lenses. It can be understood by "each actual individual lens Lri being manufactured to have the optical and geometric properties of the corresponding theoretical individual lens Lti", the fact that each lens of the same mold is intended to be positioned in a given position i of the assembly and is manufactured to have the optical and geometric properties of the theoretical individual lens Lti located in the given position i of the assembly.

[0037] The optical center of a lens can be defined as the center of symmetry of the transfer function of the optical lens.

[0038] The geometric center of an optical lens can be understood as the apex of the optical lens. The apex can be defined as the apparent center of each face. The apex can be measured or defined from an external surface or shape of the optical lens.

[0039] Preferably, the step of determining the value of the optimal rotation angle further comprises determining a spacing between the at least one actual individual lens manufactured Lri,j and the consecutive actual individual lens manufactured Lri + l,j' of the at least one combination of actual individual lenses manufactured, called optimal spacing, within the succession of lenses manufactured, for which the FTO of the at least one combination considered is maximum or is greater than a threshold value.

[0040] Alternatively, the method may be defined as comprising the step of determining, by means of the simulation model, the optimal spacing. In this case, the determination of the optimal spacing may be carried out concomitantly with the determination of the optimal angle.

[0041] Preferably, according to a first alternative, the simulation model comprises the determination of values ​​of the FTO of the at least one combination of individual real lenses manufactured obtained by successive rotations of the at least one real lens manufactured Lri,j of the at least one combination.

[0042] Preferably, according to the first alternative, the determination of the value of the optimal rotation angle and / or the determination of the optimal spacing, from the simulation model, comprises or consists of or is carried out by a method of the ascending type based on the gradient of the FTO or on the gradient of an indicator set up from the FTO. Preferably, according to the first alternative, the determination of the value of the optimal rotation angle and / or the value of the optimal spacing from the simulation model comprises or consists of or is carried out by a method of the ascending type based on the gradient of the FTO.

[0043] Preferably, the method of the ascent type based on the gradient of the FTO or on the gradient of an indicator set up from the FTO has the effect of maximizing the FTO.

[0044] Preferably, according to a second alternative, the simulation model is a neural network.

[0045] Preferably, the neural network is an acyclic neural network, more preferably a convolutional neural network. Preferably, the neural network comprises several layers of neurons, more preferably at least two, more preferably at least three layers of neurons.

[0046] Preferably, according to a second alternative, the method comprises a step of training the neural network from a training database obtained from variations of the theoretical geometry of the external surface of the theoretical lenses Lti.

[0047] Preferably, according to a second alternative, the learning database comprises input data consisting of at least one combination of theoretical individual lenses Lti each having the at least one defect, the at least one defect being obtained by introducing an error, in the form of a random variable, on each theoretical individual lens Lti of the at least one combination of theoretical individual lenses Lti each having the at least one defect.

[0048] Preferably, according to a second alternative, the learning database comprises output data consisting of the FTO values ​​of the at least one combination of theoretical individual lenses Lti each having the at least one defect. The characteristics described in the present description apply, unless otherwise indicated, to each of the aspects of the invention and to each of the alternatives according to the invention.

[0049] Preferably, the FTO is calculated or determined or simulated by an optical beam propagation calculation method.

[0050] Preferably, the method comprises a step of searching, by permutations between the positions j in the mold of the lenses of the at least one combination of real individual lenses manufactured Lri,j, for at least one additional combination of real individual lenses manufactured Lri,j for which an optical transfer function (OTF) is maximum or is greater than a threshold value.

[0051] Preferably, determining a value of the rotation angle and / or determining a value of the optimal spacing comprises maximizing a weighted combination of at least two criteria among the production yield of the line and / or the quality of the targets produced and / or the minimum dispersion of the quality of the targets produced.

[0052] Preferably, the method comprises:

[0053] - a step of measuring the geometry of the assembled optical lens,

[0054] - a step of refining the value of the optimal rotation angle and / or the value of the optimal spacing determined from the measured geometry of the assembled lens.

[0055] Preferably, measurement biases can be observed and / or determined by comparing the measurement of the geometry of the assembled lens with the measurement of the geometry of the individual fabricated lenses Lri,j forming or constituting the assembled lens.

[0056] Preferably, the method comprises measuring a geometry of the individual fabricated lenses Lri,j forming the assembled lens.

[0057] Preferably, the step of refining the value of the optimal rotation angle and / or the value of the optimal spacing comprises the steps of: modulating and / or adjusting the at least one determined defect of the manufactured lenses as a function of or taking into account the determined or observed measurement biases, and / or

[0058] - refine the determined optimal rotation angle and / or the determined optimal spacing:

[0059] • by implementing the method according to the invention in which the at least one defect comprises the measurement biases determined or observed, and / or

[0060] • relative to or in relation to or as a function of the FTO values ​​obtained by taking into account the measurement biases determined or observed.

[0061] According to another aspect of the invention, a device is proposed comprising means configured to implement all the steps of the method according to the invention.

[0062] According to the invention, a data processing device is also proposed comprising means arranged and / or programmed and / or configured to implement the method according to the invention.

[0063] According to the invention, there is also provided a computer program comprising instructions which, when the program is executed by a computer, cause the latter to implement the method according to the invention.

[0064] The computer program can be in any computer language, such as machine language, C, C++, JAVA, Python, etc.

[0065] The computer program can be integrated into the design software used for optical lens design.

[0066] Alternatively, the computer program may include the design software, or be independent of said design software.

[0067] According to the invention, there is also provided a medium, for example a recording medium, readable by a computer comprising instructions which, when executed by a computer, cause the latter to implement the method according to the invention.

[0068] According to the invention, a computer-readable data carrier is also provided, on which the computer program according to the invention is recorded.

[0069] The method according to the invention can be implemented by any type of device such as a smartphone, a tablet, a computer, a calculator, a network server, containing at least one processor, a computer chip, programmed and / or arranged and / or configured to implement the method according to the invention, for example by executing the computer program according to the invention.

[0070] According to the invention, a method is proposed for determining an arrangement of n real individual lenses Lri, according to the invention, to form a camera or a camera module.

[0071] The camera or camera module can be used in any type of device comprising at least one camera or at least one camera module such as, among others, a smartphone, a tablet, a camera, a video surveillance camera or a user device.

[0072] According to the invention, a method is provided for determining an arrangement of n actual individual lenses Lri, according to the invention, for forming an optical objective of a medical device.

[0073] The medical device can be an endoscope, an ultrasound machine, etc.

[0074] According to the invention, a method is provided for determining an arrangement of n actual individual lenses Lri, according to the invention, for forming an optical lens of a vehicle.

[0075] The vehicle may be a land vehicle, such as a car, whether autonomous or not, with semi-autonomous driving, or with autonomous driving. The vehicle may be a flying vehicle, such as a drone, an airplane, or a helicopter, for example, with non-autonomous driving, semi-autonomous driving, or autonomous driving.

[0076] The vehicle may be a marine vehicle, such as a boat or submarine, for example non-autonomous driving, semi-autonomous driving or autonomous driving.

[0077] According to the invention, a camera module is also proposed comprising:

[0078] - an optical objective designed with the method according to the invention; and

[0079] - an image sensor associated with said optical lens.

[0080] The image sensor can be any type of image sensor combined with an optical lens, such as a CMOS or CCD image sensor, but is not limited to these image sensors.

[0081] According to the invention, there is also provided an installation for manufacturing optical lenses comprising:

[0082] - an assembly apparatus configured to implement the determination method according to the invention; and

[0083] - a production line for optical lens(es).

[0084] The installation according to the invention may comprise, in terms of means and / or configuration, any combination of the optional characteristics described above in relation to the manufacturing method according to the invention and which are not repeated here for the sake of brevity.

[0085] In particular, the manufacturing facility is configured to implement the manufacturing method according to the invention.

[0086] According to the invention, there is also provided an apparatus comprising at least one optical objective designed by the method according to the invention.

[0087] The apparatus according to the invention may in particular comprise at least one camera module according to the invention.

[0088] In particular, the device may be a user device such as a smartphone, tablet, etc. The user device may optionally include a display screen, in particular a touch screen, etc.

[0089] In particular, the device may be a virtual reality headset or an augmented reality headset, intended to be worn by a user.

[0090] The helmet may optionally include a display screen, in particular a touch screen, etc.

[0091] In particular, the device may be a user device such as a camera or photo camera, etc.

[0092] The user device of the camera or photo type may optionally include a display screen, in particular a touch screen, etc.

[0093] In particular, the device may be a computer-type user device.

[0094] The computer-type user device may optionally include a display screen, in particular a touch screen, etc.

[0095] The computer-type user device may optionally include a keyboard, or any other equipment integrated or associated with said device.

[0096] In particular, the device may be a television.

[0097] The television may optionally include a display screen, in particular a touch screen, etc.

[0098] In particular, the device may be a medical imaging device.

[0099] The medical imaging device can be, for example, an endoscope, an ultrasound device, etc.

[0100] Of course, the apparatus according to the invention is not limited to the examples of apparatus which have just been given.

[0101] According to another aspect of the present invention, there is provided a vehicle comprising at least one optical lens designed with the method according to the invention.

[0102] The apparatus according to the invention may in particular comprise at least one camera module according to the invention. According to embodiments, the vehicle may be a land vehicle, such as a car, for example with non-autonomous driving, semi-autonomous driving, or autonomous driving.

[0103] According to embodiments, the vehicle may be a flying vehicle, such as a drone, an airplane, a helicopter, for example with non-autonomous driving, semi-autonomous driving or autonomous driving.

[0104] In embodiments, the vehicle may be a marine vehicle, such as a boat or a submarine, for example non-autonomous, semi-autonomous, or autonomous.

[0105] According to embodiments, the optical lens can be used for 2D or 3D imaging.

[0106] According to embodiments, the optical lens can be used for image acquisition to image a scene at a given time, or for acquiring a stream of images, or a video, of a scene.

[0107] Of course, these examples are not limiting and are just provided as an example of the possible applications of the camera modules that can be manufactured from the optical lenses manufactured using the method of the invention.

[0108] Description of figures

[0109] Other advantages and particularities of the invention will appear on reading the detailed description of implementations and embodiments which are in no way limiting, and the following appended drawings: FIGURE 1 is a diagram illustrating the steps of an embodiment of the method according to the invention, FIGURE 2 is a schematic representation of a succession of lenses aligned along the optical axis of an optical objective, FIGURE 3 is a schematic representation of a mold comprising a set of cavities in which the lenses are intended to be manufactured, FIGURES 4 and 5 are schematic representations illustrating defects present on the manufactured lenses.

[0110] Description of the embodiments

[0111] The embodiments described below being in no way limiting, it will be possible in particular to consider variants of the invention comprising only a selection of the described characteristics, isolated from the other described characteristics (even if this selection is isolated within a sentence comprising these other characteristics), if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art. This selection comprises at least one characteristic, preferably functional without structural details, or with only a part of the structural details if this part only is sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art.

[0112] Referring to FIGURE 1, there is shown an embodiment of the method for determining an arrangement of n actual individual lenses Lri to form an optical objective. The dotted symbols in the flowchart of FIGURE 1 are steps that are optional or not part of the invention.

[0113] An optical lens consists of a succession of optical lenses mounted in a barrel. The lenses can be mounted against each other, or separated from each other by a spacer. The spacer acts as a mechanical separation between the lenses and allows a given spacing to be maintained between the lenses. For an optical lens comprising n lenses, the lens will comprise at most n-1 spacers. The lenses comprise two parts, a so-called "optical" part forming the center of the lens and a so-called "mechanical" part forming the outer radial part. The optical part has an axisymmetric profile of the aspherical type and gives the lens its optical properties. The mechanical part forms a support surface that is often flat over at least one area.

[0114] The design of an optical lens is carried out according to the desired optical properties, such as, among others, the magnification, the aperture or the focal length, and the desired application. This step of designing the optical lens, referenced 1 in FIGURE 1, is not part of the invention and is implemented upstream of the method according to the invention. At the end of this step 1, a model consisting of a particular assembly, consisting of a particular succession, of theoretical individual optical lenses Lti having precise optical and geometric properties is obtained. Typically, an optical lens is made up of 4 to 10 optical lenses.

[0115] From this model, the individual lenses are manufactured. This manufacturing step is referenced 2 in FIGURE 1. In order to pre-produce and produce in quantity the optical lens, the manufacture of each lens requires the design of a composition of a material, i.e. a "recipe", intended to form the lens as well as the design of a dedicated mold comprising a set of cavities in each of which an individual lens of the assembly will be formed by casting the previously designed composition. The lens molding step is controlled by a set of parameters such as the molding time, the temperature profile seen by the injected material (which can be obtained by particular temperatures at the different injection locations) and pressure.The cavities are made so that the lenses manufactured in the same mold all have the same geometry which is supposed to correspond perfectly to the particular theoretical lens geometry Lti of the assembly. In practice, we systematically observe differences in geometry of the lenses manufactured in the same mold between themselves and differences in geometry between the lenses manufactured from the same mold and the corresponding theoretical lens Lti of the assembly. The manufacturing also includes a step of cutting the manufactured lenses, referenced 4 in FIGURE 1.

[0116] The present invention does not relate to the manufacture or assembly of the manufactured lenses itself but to determining an arrangement or orientation or positioning of the individual manufactured lenses within the assembly that compensates for or limits the effects of lens defects on the expected optical properties of the optical lens. In the state of the art, this step is performed empirically by measuring the optical properties of the optical lens comprising the assembled manufactured lenses and modifying the positioning of each of the lenses.

[0117] In order to illustrate the indexing of the manufactured lenses Lri,j used in the present application, FIGURE 2 shows a schematic representation of an optical lens consisting of an assembly of four manufactured lenses Lri,j. FIGURE 3 shows a schematic representation of a mold 50 comprising sixteen cavities 51 numbered from 1 to 16. The lenses are therefore referenced Lrl, Lr2, Lr3, Lr4 where i is the position of the lens in the assembly.The lens Lrl,j is therefore manufactured in a mold dedicated to the manufacture of the lenses located in position 1 in the assembly, the lens Lr2,j is therefore manufactured in a mold dedicated to the manufacture of the lenses located in position 2 in the assembly, the lens Lr3,j is therefore manufactured in a mold dedicated to the manufacture of the lenses located in position 3 in the assembly, the lens Lr4,j is therefore manufactured in a mold dedicated to the manufacture of the lenses located in position 4 in the assembly and j is the cavity 51 (or the position in the mold 50) in which the lens was manufactured.Thus, for example, the combination of manufactured lenses denoted Lrl,8, Lr2,5, Lr3,l, Lr4,12 corresponds to the combination of the lens located in position 8 in the mold dedicated to the manufacture of the lenses located in position 1 in the assembly, of the lens located in position 5 in the mold dedicated to the manufacture of the lenses located in position 2 in the assembly, of the lens located in position 1 in the mold dedicated to the manufacture of the lenses located in position 3 in the assembly and of the lens located in position 12 in the mold dedicated to the manufacture of the lenses located in position 4 in the assembly.Also, according to the invention, and with reference to the embodiment presented, "a combination of four manufactured lenses Lri,j" corresponds to a combination of four manufactured lenses consisting of: a lens manufactured in a cavity j of the mold dedicated to the manufacture of the lenses located in position i=1 in the assembly, a lens manufactured in a cavity j of the mold dedicated to the manufacture of the lenses located in position i=2 in the assembly, a lens manufactured in a cavity j of the mold dedicated to the manufacture of the lenses located in position i=3 in the assembly and a lens manufactured in a cavity j of the mold dedicated to the manufacture of the lenses located in position i=4 in the assembly.

[0118] The method for determining an arrangement of n individual real lenses Lri to form an optical objective, called method, according to the invention comprises a step of determining defects of each manufactured lens Lri,j. This step is referenced 5 in FIGURE 1. The step of determining the defects is carried out from the real geometry of the manufactured lenses Lri,j and from the theoretical geometry of at least one of the faces of the theoretical lens Lti corresponding to the manufactured lens considered.

[0119] The actual geometry of an individual lens manufactured Lri,j is understood to be the external surface delimiting the lens. The geometry as well as the optical properties of each of the theoretical lenses Lti is known because they have been previously modeled.

[0120] The method may comprise a step of measuring the actual geometry of at least one of the two faces of each manufactured lens Lri,j. The measuring step is referenced 3 in FIGURE 1. The measuring step may be optical, by interferometry for example. By comparison with the geometry of the corresponding theoretical lens Lti, defects in shape, thickness and optical index are determined for each manufactured lens Lri,j.

[0121] However, the method may not include the step of measuring the actual geometry of at least one of the two faces of a manufactured lens Lri,j. In this case, instead of including the step of measuring the actual geometry of at least one of the two faces of a manufactured lens Lri,j (step referenced 3 in FIGURE 1), the method may include a step of providing or obtaining the actual geometry of the manufactured lenses Lri,j or data relating to the actual geometry of the manufactured lenses Lri,j.

[0122] An example of shape defects of a fabricated lens Lri,j is shown in FIGURES 4 and 5. Shape defects can be:

[0123] - a difference in geometric shape of the manufactured lens Lri,j compared to the corresponding theoretical lens Lti,

[0124] - an offset of the position of the geometric center of each face of the manufactured lens Lri,j relative to the optical axis 20 of the optical objective,

[0125] - an offset of the position of the optical center of the manufactured lens Lri,j relative to the optical axis 20 of the optical objective,

[0126] - an inclination of the manufactured lens considered relative to the optical axis, and / or

[0127] - a difference in thickness between the two sides of the lens.

[0128] Advantageously, a defect consisting of a difference in refractive index of the manufactured lens Lri,j compared to the corresponding theoretical lens Lti is also determined.

[0129] Advantageously, a defect consisting of a spacing difference between two consecutive manufactured lenses Lri,j of the assembly is also determined.

[0130] Defects related to the position of the geometric centers, the inclination of the lens, the difference in refractive index and the spacing deviation between the lenses are related to and / or determined from, at least in part:

[0131] - of the external surface of one or both sides of the lens, and / or

[0132] - the geometry of the external surface of one or both faces of the lens, and / or

[0133] - of the external surface and / or the geometry of the external surface of the optical part and / or the mechanical part of the lens, and / or - defects of the external surface of one or both faces of the lens and / or the geometry of the external surface of one or both faces of the lens, and / or of the external surface and / or the geometry of the external surface of the optical part and / or the mechanical part of the lens.

[0134] According to a non-limiting example presented in FIGURES 4 and 5, the external surface 11 of a manufactured lens Lri,j is presented after measuring the geometry of the manufactured lens and the external surface 12 of a corresponding theoretical lens Lti. Also, the continuous line curve 11 corresponds to the real external surface 11 or to the real shape 11 of the manufactured lens Lri,j and the curve with the circles 12 corresponds to the theoretical surface 12 or expected or to the theoretical shape 12 or expected. In FIGURES 4 and 5, these real surfaces 11 and expected surfaces 12 are reported in a coordinate system associated with this lens. Preferably, the system is the one which is on the support plane on which the lens is placed or intended to be placed (the plane can be that of contact with the previous lens or a plane normal to the axis of the barrel).

[0135] FIGURES 4 and 5 also show the measured normal shape vector 13 and the theoretical normal shape vector 14. This normal shape vector represents the normal vector to the apex 15 of the lens.

[0136] FIGURE 4 shows the measured aspherical surface 11 of the unregistered manufactured lens relative to the aspherical surface 12 of the corresponding theoretical lens.

[0137] In FIGURE 5, the measured aspherical surface 11 of the manufactured lens is illustrated, which is registered with respect to the aspherical surface 12 of the corresponding theoretical lens. The registration 16 can be implemented by an icp (iterative closest point) type algorithm or variants thereof, for example, to find a solid transformation that minimizes the sum of the distances of the projection of the measured points onto the aspherical surface of the corresponding theoretical lens. The registration 16 makes it possible to characterize more precisely the positioning defects of the optical center, thickness and inclination, by subtracting the two curves obtained as presented in FIGURE 5.

[0138] Still according to the non-limiting example, after the 16-fold registration, the shape error is decomposed on a surface shape basis, for example the Zernike basis. The first coefficients of this decomposition are kept to characterize the shape errors, for example those corresponding to the defocus mode, 2 coma modes, 2 astigmatism modes and 2 trefoil modes. According to the example, the piston and tilt modes are ignored because they are taken into account in the thickness and inclination defects and are already compensated by the 16-fold registration.

[0139] It is recalled that the non-limiting example described above is optional and that all form defects can be measured directly.

[0140] As for the refractive index and / or refractive index gradient in the fabricated lens, it can be determined, for example, from the measurement of the optical path between the two faces of the fabricated lens.

[0141] The method according to the invention also comprises, for a combination of manufactured lenses Lri,j considered, a step of determining, by a simulation model, a value of an optimal rotation angle, having as its axis of rotation the optical axis of the optical objective 20, of the manufactured lenses Lri,j of the lens combination Lrl,j, Lr2,j, Lr3,j, Lr4,j for which an optical transfer function (OTF) of the at least one combination is maximum or is greater than a threshold value. The value of the rotation angle thus determined, for the combination of manufactured lenses Lri,j considered, is called the optimal angle. The step of determining the optimal angle is referenced 6 in FIGURE 1. As an example, considering the combination of fabricated lenses Lrl,8, Lr2,5, Lr3,l, Lr4,12, an optimal angle will be determined for the fabricated lens Lrl,8, for the fabricated lens Lr2,5, for the fabricated lens Lr3,l and for the fabricated lens Lr4,12.

[0142] According to the invention, the modulation transfer function (MTF) can be used instead of the OTF.

[0143] The first aim of the invention is to find, for at least one combination of n individual lenses manufactured Lri,j, an optimal angle value of the individual lenses manufactured Lri,j and / or a value of an optimal spacing between the individual lenses manufactured Lri,j for which the at least one combination of actual lenses manufactured Lri,j offers the best optical properties, i.e. an FTO greater than a threshold value or the best FTO.

[0144] The method is then advantageously applied to all or part of the set of possible individual lens combinations Lri,j manufactured.

[0145] Depending on the cases, the needs and the desired goal, it may be advantageous to define a threshold value of FTO above which the optical properties of the objective formed by the combination of manufactured lenses considered are considered acceptable. As a non-limiting example, the threshold value of FTO can be between 0.65 and 0.8. This option avoids iterating the process for each of the possible combinations of manufactured lenses. In certain cases, it is possible to obtain a value of FTO higher than the threshold value by varying the rotation angle of only one or some of the lenses of the combination of manufactured lenses considered.In some cases, obtaining an FTO value above the threshold value will require varying the rotation angle of several or all of the lenses in the considered manufactured lens combination in order to find the combination of lens rotation angles providing an FTO value above the threshold value.

[0146] When it is required that the optical objective has the best optical properties, it is then possible to iterate the process for each of the possible manufactured lens combinations and select the best one(s), i.e. the one(s) for which the FTO is maximum. It is also possible to iterate the process for each of the possible manufactured lens combinations and select the manufactured lens combinations Lri,j allowing to use all the manufactured lenses Lri,j, i.e. to manufacture m optical objectives.

[0147] Advantageously, also, for a considered combination of manufactured lenses Lri,j, the method further comprises determining a spacing, called optimal spacing, between the actual individual manufactured lenses Lri,j of the considered combination of manufactured lenses Lri,j for which the FTO of the at least one combination considered is maximum or is greater than a threshold value. The threshold value may be identical or different depending on whether or not the method comprises determining the optimal spacing. When the method comprises determining the optimal spacing, the threshold value of the FTO may be greater than in the case where the method only comprises determining the optimal angle. Preferably, the method comprises determining the optimal spacing between each of the actual individual manufactured lenses Lri,j of the considered combination of manufactured lenses Lri,j.

[0148] The determination of the optimal spacing is then advantageously applied to all or part of the set of possible individual lens combinations Lri,j manufactured.

[0149] Advantageously, the determination of the optimal angle and the optimal spacing are implemented in the same step by the simulation model. The step of determining the optimal spacing is referenced 6 in FIGURE 1.

[0150] The spacer is considered a lens without an optical surface. The two spacer bearing surfaces on the two adjacent manufactured lenses can be characterized by measurement.

[0151] Thus, the lens assembly parameters including, among others, the optimal rotation angle of each lens and, preferably, the geometric characteristics of the spacers will be restored at the end of the process. The restitution step is referenced 7 in FIGURE 1. From these values, it will be possible to calculate the absolute positions of the lens surfaces. If necessary, the mechanical properties of the materials can be taken into account in order to calculate the positions of the elements more precisely by balancing the mechanical constraints between the elements.

[0152] According to an advantageous embodiment, it is possible to categorize, in a limited number of classes, the shape defects, the thickness and / or the refractive index of each type of manufactured lens Lri,j, for example as a function of the position j of the mold cavity in which the lens is molded at each cycle. It is possible to implement, in the simulation model, a combination between the lens classes so that the optical quality of each class is maximized and with a confined quality dispersion.

[0153] FIGURE 1 also shows the step of restoring the combination or combinations of individual lenses manufactured Lri,j and the value of the optimal angle or values ​​of the optimal angles for each of the lenses manufactured in the combination or each combination and / or the value of the optimal spacing or values ​​of the optimal spacing between each of the lenses manufactured in the combination or each combination.

[0154] According to an advantageous embodiment of the first alternative, the resolution of the optimal angle and / or the optimal spacing, from the simulation model, uses a gradient type method. For example, any numerical optimization method, for example, of the gradient type, conjugate gradient, ascent method (or descent by changing the sign of the criterion to be achieved) based on a gradient, quasi-newton, newton, confidence region, Levenberg Marquard, may be used to resolve the optimal angle and / or the optimal spacing.

[0155] According to a first alternative, the simulation model comprises the determination of FTO values ​​of the combination of individual real lenses manufactured Lri,j considered obtained by successive rotations of the real lenses manufactured Lri,j of the combination considered.

[0156] In other words, for the purposes of a simplified description and by way of non-limiting example, for the combination considered, it is possible to keep the lenses Lrl,8, Lr2,5 and Lr3,l fixed, and to vary the angle of rotation of the lens Lr4,12 until the optimal angle is found, then to vary the angle of rotation of the lens Lr3,l while keeping the lenses Lrl,8, Lr2,5 and Lr4,12 fixed and so on.

[0157] Successive rotations can be performed in constant angle steps, for example 1°, 5°, 10°, 45° or 90°. It is possible to select a large angle step, for example 45° or 90°, and to infer a trend in the evolution of the FTO to guide the model towards an optimal solution by performing fewer successive rotations.

[0158] One of the main advantages of the method according to the invention is to be able to find an alternative to the empirical approach, as described above, in order to find the set of optimal rotations simultaneously and without discretization. Also, preferably, according to the first alternative, one can, for example, calculate the angles according to continuous values ​​(therefore taken continuously in the interval 0-360°), and globally calculate a set of rotation for each lens Lri,j with i scanning the indices of the lenses of the assembly and a choice of indices j for each i (for example j=8 for i = l, j = 5 for i = 2, j = l for i = 3, j = 12 for i = 4) in order to obtain an optimal solution in terms of FTO.

[0159] According to the first alternative, the simulation model includes the determination of FTO values ​​of the combination of real individual lenses manufactured Lri,j considered obtained by successive modification of the spacing around the theoretical spacing value between two theoretical lenses, noted Thi. The successive variations of the spacing value can be carried out in turn by increasing, at constant steps, the spacing value Thi beyond the theoretical spacing value and then by decreasing, at constant steps, the spacing value below the theoretical spacing value. (This choice of a constant step can correspond to a set of possible discrete values ​​of the physically available spacers).

[0160] According to an advantageous embodiment of the first alternative, the method comprises a step of searching, by permutations between the positions j in the mold, for a combination of actual individual lenses manufactured Lri,j for which an optical transfer function (OTF) of the at least one combination considered is maximum or is greater than the threshold value.

[0161] It is possible to denote by S the matrix encoding the set of combinations of actual individual lenses manufactured. The permutations can be carried out randomly or incrementally or according to a series of given permutations or a given mode of permutation of the positions j within the matrix S.

[0162] According to a second alternative, the simulation model is a convolutional neural network. A person skilled in the art will know how to adapt and use the most appropriate neural network. As a non-limiting example, the convolutional neural network may comprise several layers of neurons. Among these layers of neurons, the network comprises processing layers comprising neurons arranged to process the input data and transfer them to the output data, based on convolutions and non-linear functions. The neural network may also comprise sub-sampling (or pooling) layers, interposed between two processing layers, comprising neurons arranged to combine or merge the output data of the processing layers and reduce their size.By way of non-limiting example, the convolutional neural network may further comprise a correction layer, interposed between two processing layers, comprising neurons arranged to operate an activation function on the output data of the processing layers.

[0163] Advantageously, the method comprises training the neural network from a training database. According to the embodiment, the database is obtained from variations of the theoretical geometry of the external surface of the theoretical lenses Lti. The training database comprises input data consisting of at least one combination of theoretical individual lenses Lti each having the at least one defect, the at least one defect being obtained by introducing an error, in the form of a random variable, on each theoretical individual lens Lti of the at least one combination of theoretical individual lenses Lti each having the at least one defect. In practice, a predefined number of errors to be introduced is fixed and these errors are introduced randomly on the theoretical lenses Lti.As a non-limiting example, ten typical defects are considered per lens face, i.e. 80 typical defects for an assembly of four lenses. Each typical defect is associated with a random variable. These random variables are drawn for the typical defects of the lens assembly considered, for example ten thousand or one hundred thousand times, thus corresponding to ten thousand or one hundred thousand different lens assemblies, i.e. ten thousand or one hundred thousand different optical objectives, each presenting a set of several defects. The TFO is then calculated for each of the cases.

[0164] The training database also includes output data consisting of the FTO values ​​of the at least one theoretical individual lens combination Lti each having the at least one defect.

[0165] According to the invention, the FTO is simulated by a method for calculating the propagation of optical beams. Several calculation methods of this type are known in the state of the art. For example, the OpticStudio® software sold by the company Zemax® is known.

[0166] According to an advantageous embodiment of the invention, the determination of the optimal rotation angle and / or the determination of the optimal spacing comprises a maximization of a weighted combination between at least two criteria among the production yield of the line and / or the quality of the objectives produced and / or the minimum dispersion of the quality of the objectives produced.

[0167] In other words, the aim here is to search for the individual lens combinations within the matrix S, for which the determination of the optimal rotation angle and / or the determination of the optimal spacing is conditioned to improve the production efficiency of the line and / or the quality of the lenses produced and / or the minimum dispersion of the quality of the lenses produced. In other words, the search for the manufactured lens combinations for which the lens angle is optimal and / or the spacing between the lenses is optimal will here be conditioned to also satisfy a weighted combination between at least two criteria among the production efficiency of the line and / or the quality of the lenses produced and / or the minimum dispersion of the quality of the lenses produced.

[0168] Therefore, the combinations of actual individual lenses manufactured will be sought, for which the rotation angle of the lenses is optimal and / or the spacing between the lenses is optimal, satisfying the weighted combination of criteria to be maximized.

[0169] There are a large number of functions or relations that can be used to express the desired solution.

[0170] One of the aims of the invention may relate to production efficiency. In this case, it is sought that each manufactured lens Lri,j (i.e. each lens manufactured in a cavity of a mold) can be used, within a combination of n individual manufactured lenses Lri,j, to, after assembly, form an optical lens. In other words, the aim is to use all the manufactured lenses to assemble as many optical lenses as there are manufactured lenses Lri,j per mold. There will therefore be as many optical lenses assembled as there are cavities in the molds, i.e. m optical lenses manufactured. The aim is therefore to find m combinations of individual lenses by searching for the combinations of actual manufactured lenses Lri,j offering the best optical properties, i.e. the best possible FTO.As a non-limiting example, the solution for maximizing the efficiency of the chain can be expressed as the search for several combinations of assemblies P with FTO(P)>FTOseuii, by maximizing the number of objectives produced from the mi available cavities of each type of lens i (i.e. if for example the mi are all worth a number m, we can have up to m objectives produced in parallel), FTO(P) is the value of the FTO of the combination(s) sought and FTOseuii is the threshold value of the defined FTO.

[0171] Another aim of the invention may relate to the quality of the optical objectives. In this case, the combinations of n individual lenses manufactured Lri,j are sought which offer the best optical properties, i.e. the best FTO. In this case, it is possible, and even probable, that the number of optical objectives which will be manufactured is less than m. As a non-limiting example, the solution for maximizing the quality of the optical objectives can be expressed as argmaxp min(FTO(S)) where FTO(S) corresponds to the FTO values ​​of all the combinations of individual lenses manufactured Lri,j and p the set of permutations envisaged.

[0172] Another aim of the invention may be to minimize the dispersion between the optical properties of the optical lenses. In this case, combinations of n individual lenses manufactured Lri,j are sought for which the variations in optical properties between the lenses are minimal, i.e. the optical lenses, after assembly, have a similar or identical FTO. As a non-limiting example, the solution for minimizing the dispersion of the quality of the optical lenses can be expressed as argminpZH(FTO(S)) where H(FTO(S)) is the entropy of the FTO.

[0173] It is also possible to want to achieve more than one of the three goals sought above. In this case, it will be necessary to maximize a weighted combination of at least two criteria among the production efficiency of the chain and / or the quality of the product objectives and / or the minimum dispersion of the quality of the product objectives.

[0174] It should be noted that the different threshold values ​​of the FTO defined in the present description, within the framework of the different improvements and / or different embodiments, may be identical or different. In particular, and by way of example, if only the optimal rotation angle or only the spacing is sought, the threshold value of the FTO will preferably be different, preferably even lower, than the threshold value of the FTO used when the optimal rotation angle and the optimal spacing are sought.

[0175] According to an advantageous embodiment of the invention, the method comprises a step of measuring a geometry of the assembled optical lens. This step is referenced 8 in FIGURE 1. The measurement of the geometry of the assembled optical lens may be carried out by a method, for example an optical method, which may be the same as or different from the method used to measure or characterize the surface or geometry of the individual lenses manufactured.

[0176] The measured geometry of the assembled lens may differ from the expected geometry calculated from measurements made on the individual manufactured lenses Lri,j. This may be due to measurement errors on the individual manufactured lenses Lri,j and / or the calculation may have ignored an unforeseen effect and / or the elasticity of the material may have been underestimated or overestimated. In this case, the measurement after assembly can allow the model to be recalibrated empirically by adding these deviations to the predictions made from measurements on the individual manufactured lenses Lri,j to be more accurate in the end.

[0177] According to this advantageous embodiment, the method also comprises a step of refining the value of the optimal rotation angle and / or the value of the optimal spacing determined from the measured geometry of the assembled lens. For example, the measured geometry of the optical lens may be taken into account, by the simulation model, when implementing the step of determining the optimal rotation angle and / or the value of the optimal spacing.

[0178] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

[0179] Thus, the variants of the previously described embodiments can be combined with each other.

[0180] In addition, the various features, forms, variations and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

Claims

CLAIMS 1. Method for determining an arrangement of n real individual lenses Lri to form an optical objective, the real individual lenses Lri are intended to be assembled along an optical axis of the optical objective in accordance with a model, previously designed to have specific optical properties, consisting of a particular succession of n theoretical individual lenses Lti, where i is the position of the lens in the optical objective and i is between 1 and n;each actual individual lens Lri being manufactured to have the optical and geometric properties of the corresponding theoretical individual lens Lti within the optical objective and each actual individual lens Lri being manufactured in batches of half lenses in a manufacturing mold dedicated to the manufacture of the actual individual lens Lri, the actual individual lenses manufactured are denoted Lri,j where j is the position of the lens in the mold and j is between 1 and m, said method comprises the steps of: for each manufactured lens Lri,j, determining, from an actual geometry of at least one of the two faces of a manufactured lens Lri,j considered and from the theoretical geometry of at least one of the faces of the theoretical lens Lti corresponding to the manufactured lens considered, the presence of at least one of the following defects:; • a difference in geometric shape of the manufactured lens considered compared to the corresponding theoretical lens, • a difference in the refractive index of the manufactured lens considered compared to the corresponding theoretical lens and / or a difference in the dependence of the refractive index on the wavelength, • an offset of the position of the geometric center of each face of the manufactured lens considered relative to the optical axis of the optical objective, • an offset of the position of the optical center of the manufactured lens Lri,j relative to the optical axis 20 of the optical objective, • an inclination of each face of the manufactured lens considered relative to the optical axis, • a difference between a thickness of the manufactured lens considered and a thickness of the corresponding theoretical lens, • a difference between a spacing between the considered manufactured lens and the manufactured lens subsequent to the manufactured lens considered within the succession of lenses and a spacing between the theoretical lens corresponding to the manufactured lens considered and the theoretical lens consecutive to the theoretical lens corresponding within the succession of lenses, for at least one combination of n individual real lenses manufactured, each comprising at least one of the defects, and for at least one real lens manufactured Lri,j of the at least one combination of individual real lenses manufactured, determining, by means of a simulation model, a value of a rotation angle, having as its axis of rotation the optical axis of the optical objective, of the at least one real lens manufactured Lri,j of the at least one combination of individual real lenses manufactured Lri,j, called optimal angle, for which an optical transfer function (OTF) of the at least one combination, representative of the desired optical quality, is maximum or is greater than a threshold value.

2. Method according to claim 1, in which the step of determining the value of the optimal rotation angle further comprises determining a spacing between the at least one actual individual lens manufactured Lri,j and the consecutive actual individual lens manufactured Lri + l,j' of the at least one combination, called optimal spacing, within the succession of lenses manufactured, for which the FTO of the at least one combination considered is maximum or is greater than a threshold value.

3. The method of claim 1 or 2, wherein determining the value of the optimal rotation angle or the value of the optimal spacing from the simulation model comprises determining FTO values ​​of the at least one combination of individual real lenses manufactured obtained by successive rotations of the at least one real lens manufactured Lri,j of the at least one combination.

4. Method according to any one of the preceding claims, in which the determination of the value of the optimal rotation angle, from the simulation model, comprises a method of the ascent type based on a gradient of the FTO.

5. Method according to claim 2 or any one of claims 3 or 4 taken in combination with claim 2, in which the determination of the value of the optimal spacing, from the simulation model, comprises a method of the ascent type based on an FTO gradient.

6. Method according to claim 1 or 2, in which the simulation model is a neural network.

7. Method according to the preceding claim, comprising training the neural network from a training database obtained from variations of the theoretical geometry of the external surface of the theoretical lenses Lti.

8. Method according to the preceding claim, in which the learning database comprises: - input data consisting of at least one theoretical individual lens combination Lti each having the at least one defect, the at least one defect being obtained by introducing an error, in the form of a random variable, on each theoretical individual lens Lti of the at least one theoretical individual lens combination Lti each having the at least one defect, - output data consisting of the FTO values ​​of the at least one theoretical individual lens combination Lti each having the at least one defect.

9. A method according to any preceding claim, wherein the FTO is calculated or determined or simulated by an optical beam propagation calculation method.

10. Method according to any one of the preceding claims, comprising a step of searching, by permutations between the positions j in the mold of the lenses of the at least one combination of real individual lenses manufactured Lri,j, for at least one additional combination of real individual lenses manufactured Lri,j for which an optical transfer function (OTF) is maximum or is greater than a threshold value.

11. Method according to any one of the preceding claims, in which the step of determining a value of the rotation angle comprises a maximization of a weighted combination between at least two criteria among the production yield of the line and / or the quality of the objectives produced and / or the minimum dispersion of the quality of the objectives produced.

12. A method according to claim 2 or any one of claims 3 to 11 taken in combination with claim 2, wherein the value of the optimal spacing comprises a maximization of a weighted combination between at least two criteria among the production efficiency of the line and / or the quality of the objectives produced and / or the minimum dispersion of the quality of the objectives produced.

13. Method according to any one of the preceding claims, comprising: - a step of measuring the geometry of the assembled optical lens, - a step of refining the value of the optimal rotation angle determined from the measured geometry of the assembled lens.

14. A method according to claim 2 or any one of claims 3 to 13 taken in combination with claim 2, comprising: - a step of measuring the geometry of the assembled optical lens, - a step of refining the optimal spacing value determined from the measured geometry of the assembled lens 15. The method of claim 13 or 14, comprising: measuring a geometry of the individual fabricated lenses Lri,j intended to be assembled to form the assembled lens, and a step of determining measurement bias by comparing the geometry of the measured assembled lens with the geometry of the individual fabricated lenses Lri,j intended to be assembled to form the assembled lens, and - adjusting and / or modulating the at least one determined defect according to the determined measurement biases, and / or a step of refining the determined optimal rotation angle and / or the determined optimal spacing: • by implementing the method according to the invention in which the at least one fault comprises the determined measurement biases, and / or • based on the FTO values ​​obtained by taking into account the determined measurement biases.

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