Methods for examining the geometric and optical characteristics of trimmed ophthalmic lenses and related devices.

Abstract

------28 / 07 / 2559------(OCR) ------------

Description

METHOD FOR VERIFYING A GEOMETRIC AND OPTICAL CHARACTERISTIC OF A CUT OPHTHALMIC LENS AND DEVICE PARTNER TECHNICAL FIELD TO WHICH THE INVENTION RELATES The present invention relates generally to the field of methods for verifying trimmed ophthalmic lenses. It relates more specifically to a method for verifying a geometric characteristic and an optical characteristic of a trimmed ophthalmic lens. It also relates to a device for verifying at least one geometric and / or optical characteristic of a trimmed ophthalmic lens. TECHNOLOGICAL BACKGROUND Ophthalmic lenses intended to be mounted in a particular spectacle frame are manufactured from an initial circular lens with the optical characteristics required by the wearer's prescription. To this end, this initial lens is contoured to present a contour adapted to the frame of glasses chosen by the wearer, this contour being centered in the initial lens according to geometric-morphological characteristics of the wearer, such as the interpupillary distance and / or according to characteristics related to the placement of the frame on the wearer's face, for example the height of the pupils in relation to the lower edge of the frame or of the lens in place on the wearer's head, and / or according to optical characteristics desired for the contoured ophthalmic lens according to the wearer's prescription. Thus, after the initial lens has been cut, it is known to carry out a check of the cut ophthalmic lens obtained, in order to verify, on the one hand, that the final contour of the cut ophthalmic lens corresponds to the desired contour according to the chosen frame of glasses, and that the optical characteristics of the cut ophthalmic lens correspond to the desired optical characteristics according to the wearer and the chosen frame. This inspection is carried out manually and visually, in several stages according to non-standardized protocols. This makes the inspection lengthy and tedious. Furthermore, it is not very precise. SUBJECT OF THE INVENTION In order to remedy the aforementioned drawbacks of the prior art, the present invention proposes a new method for verifying a geometric characteristic and an optical characteristic of a contoured ophthalmic lens, allowing for more precise and faster control of contoured lenses. More specifically, the invention proposes such a method comprising the following steps: a) The cut-out ophthalmic lens is placed on a support, b) at least one image of this outlined ophthalmic lens is captured, c) a measured geometric characteristic of said outlined ophthalmic lens is determined from this image, d) at least one measured optical feature of this ophthalmic lens is determined in a frame of the image captured in step b), e) said measured geometric feature associated with the measured optical feature is compared to a predetermined desired ophthalmic lens model, comprising at least one corresponding desired geometric feature and one corresponding desired optical feature. Thus, thanks to the verification method according to the invention, it is possible to automate and systematically inspect trimmed ophthalmic lenses. This inspection is carried out quickly. The manufacturing time for ophthalmic lenses is reduced. In addition, the accuracy of controlling the geometric and optical characteristics of the lens is improved. Thanks to the method according to the invention, the contour and optical characteristics of the lens can be verified before mounting the ophthalmic lens in the chosen frame. The quality of the trimmed ophthalmic lenses sent to the optician for subsequent mounting in the frame is ensured. Furthermore, thanks to the method according to the invention, defects in the measured geometric or optical characteristics can be quantified and recorded in order to establish statistical databases on trimmed ophthalmic lenses. The traceability of ophthalmic lenses is improved. Other non-limiting and advantageous features of the method according to the invention, taken individually or in all technically possible combinations, are as follows: - in step c), said measured geometric feature is the measured contour of the contoured ophthalmic lens and, in step e), the desired ophthalmic lens model includes a desired contour; - in step d), the said optical characteristic comprising the position of the optical center and / or the direction of an optical axis of the trimmed ophthalmic lens, the following sub-steps are carried out: d1) prior to step a), the trimmed ophthalmic lens is placed in a lensometer and a mark indicating the optical center and / or the direction of the optical axis is affixed to said trimmed ophthalmic lens, d2) we identify the image of this brand on the image captured in step b); - the support of said contoured ophthalmic lens being disposed between an image capture device adapted to capture the image of this ophthalmic lens in step b), and a device for displaying a fixed pattern, in step d), an image of this fixed pattern is captured through the contoured ophthalmic lens using said image capture device, and said optical characteristic is determined as a function of this image; - the support of said contoured ophthalmic lens being disposed between an image capture device adapted to capture the image of this ophthalmic lens in step b), and a device for displaying a scrolling pattern, in step d), a plurality of images of this scrolling pattern are captured by means of said image capture device through the contoured ophthalmic lens and said optical characteristic is determined as a function of this plurality of images; - in step d), the scrolling pattern displayed by the display means having a predetermined spatial period and said plurality of images comprising a number m of images, each image capture of said plurality of images by the image capture device corresponds to the display of the scrolling pattern offset by a distance equal to 1 / m times the spatial period of this scrolling pattern relative to the previous capture; - in step d), an enhanced image of said lens is determined ophthalmic lens cut out by a statistical processing of said plurality of images of the pattern passing through the cut-out ophthalmic lens; - in step d), the image of at least one of the following elements is identified on said enhanced image of said cropped ophthalmic lens: - engravings made on the surface of the contoured ophthalmic lens or within the volume of the contoured ophthalmic lens, - the measured outline of the cut-out ophthalmic lens, - the outline of a disc with a different optical power than that of the rest of the cut-out ophthalmic lens, - defects in the coating of the trimmed ophthalmic lens; - the image capture device is focused on the support or on the ophthalmic lens to be outlined, which is placed on this support, at a distance from the display device; - in step c), where said measured geometric characteristic is the measured contour of the contoured ophthalmic lens, and, in step e), the desired ophthalmic lens model includes a desired contour, the following sub-steps are carried out: e1) The measured contour is superimposed on the desired contour, minimizing the difference between them. e2) we determine the difference between the measured optical characteristic and the desired optical characteristic as a function of the superposition carried out in step e1); - in step d), said measured optical characteristic of this trimmed ophthalmic lens includes at least one of the following characteristics: - position of a measured optical center, - direction of a measured optical axis, - measured direction of a shade gradient of the outlined ophthalmic lens, - measured direction of a polarization axis of the cut-out ophthalmic lens; - in step f), a parameter relating to the difference between said measured geometric characteristic and said desired geometric characteristic is determined based on the comparison made in step e), as well as a parameter relating to the difference between said measured optical characteristic and said characteristic desired optics; - in step f), we compare said parameter relating to the difference between said measured geometric characteristic and said desired geometric characteristic and said parameter relating to the difference between said measured optical characteristic and said desired optical characteristic to tolerance threshold values ​​and we determine, based on this comparison, a conformity indicator of the contoured ophthalmic lens; - in step g), a parameter relating to the difference between said optical characteristics measured for a right lens and a left lens intended for said mount is determined based on the comparison carried out in step e); and, - in step g), the parameter relating to the difference between the optical characteristics measured for a right lens and a left lens intended for the frame is compared to a threshold tolerance value and a conformity indicator for the right and left contoured ophthalmic lenses is determined based on this comparison. The invention also proposes a device for verifying at least one geometric and / or optical characteristic of a trimmed ophthalmic lens comprising: - a support for said contoured lens, - on one side of this support, an image capture device, - on the other side of this support, a display device adapted to display at least one scrolling pattern and to scroll this pattern in at least one predetermined scrolling direction relative to said support, - means of synchronizing a plurality of image captures by the image capture device and the scrolling of the pattern produced by the display device, - means of determining said geometric and / or optical characteristic of the cropped ophthalmic lens according to the plurality of image captures made and of comparing this geometric and / or optical characteristic with a corresponding desired characteristic. Advantageously, said scrolling pattern comprises alternating black and white bands and in which the image capture device is focused near the support, at a distance from said scrolling pattern. In addition, the scrolling pattern displayed by the display means having a predetermined spatial period, the synchronization means are programmed to trigger a number m of image captures, each image capture of said plurality of images by the image capture device corresponding to the display of the scrolling pattern offset by a distance equal to 1 / m times the spatial period of this pattern relative to the previous capture. DETAILED DESCRIPTION OF AN EXAMPLE OF IMPLEMENTATION The description that will follow with regard to the attached drawings, given by way of non-limiting examples, will make it clear what the invention consists of and how it can be implemented. Regarding the attached drawings: - Figure 1 is a schematic view of a verification device according to the invention, - Figure 2 is a schematic view of the measured contour and measured optical characteristics of a contoured ophthalmic lens superimposed on the desired contour and optical characteristics for this contoured ophthalmic lens, - Figures 3 to 7 are five schematic views of a scrolling pattern seen through the outlined ophthalmic lens, this scrolling pattern being shifted by a distance equal to 1 / 5 times the spatial period of this pattern between each successive figure, along the direction of this spatial period, the pattern here being a vertical line, - Figures 8 to 12 are five schematic views of another scrolling pattern seen through the outlined ophthalmic lens, this scrolling pattern being shifted by a distance equal to 1 / 5 times the spatial period of this pattern between each successive figure, along the direction of this spatial period, the pattern here being a horizontal line, - Figure 13 is a schematic view of the image obtained by statistical processing of images 3 to 7 and / or 8 to 12. Device Figure 1 shows a device 100 for verifying at least one geometric and / or optical characteristic of a contoured ophthalmic lens 10 according to the invention. This verification device 100 is adapted to implement the verification method according to the invention. As shown in Figure 1, this verification device 100 comprises: - a support 1 10 for said contoured lens 10, - on one side of this support 1 10, an image capture device 120, - on the other side of this support 1 10, a display device 130 adapted to display at least one scrolling pattern 150, 250 and to scroll this pattern in at least one predetermined scrolling direction relative to said support 1 10, - synchronization means 140 of a plurality of image captures by the image capture device 120 and the scrolling of the scrolling pattern 150, 250 produced by the display device 130, - means of determining said measured geometric and / or optical characteristic of the cut-out lens 10 as a function of the plurality of image captures made and of comparing this measured geometric and / or optical characteristic with a corresponding desired geometric and / or optical characteristic. More specifically, here, support 1 10 includes a plate made of transparent material, for example glass or transparent plastic material. The support 1 10 is here intended to receive the trimmed ophthalmic lens alone. The contoured lens 10 is for example placed directly on this plate, with its rear face 1 1 oriented towards the support 1 10 and its front face 12 oriented towards the image capture device 120. Alternatively, the support is designed to receive the contoured ophthalmic lens onto which a locking pin is fixed. It can indeed be envisaged that the support also includes a locking pin fixed to the front face of the contoured lens and that the plate includes means for receiving this locking pin. The locking pin is preferably the same pin used to hold the lens during its contouring. The contoured ophthalmic lens is then oriented with its front face towards the support and its rear face towards the image capture device. Advantageously, the clipped lens is then placed back into the reference frame used for the clipping. Furthermore, in this way, subsequent images of the clipped lens do not suffer distortion due to an unwanted tilt of the lens's mean clipping plane relative to the image capture plane. Alternatively, the support is designed to receive the contoured ophthalmic lens mounted in a glasses frame. It is then possible to consider that the contoured lens is mounted in the frame chosen by the wearer and that the support includes means of fixing the pair of glasses including this frame and the contoured lenses mounted in this frame. The checks can then advantageously be carried out on the lens in situ within the eyeglass frame. The mount can also be designed to simultaneously accommodate both contoured lenses for the same mount. The field of view of the image capture device must then be sufficient to simultaneously capture an image of both contoured lenses placed on the mount. The support 1 10 is preferably equipped with a scale marker allowing the scale factor of the images to be deduced from the image of this scale marker identified on an image captured by the image capture device. The image capture device 120 is, for example, a digital camera or a digital camcorder. This image capture device 120 is positioned on the side of the support 1 10 which houses the contoured lens 10. A lens or optical system can be provided between the image capture device and the contoured lens 10 supported by the support 110 so as to make the device 100 telecentric. The image captured by the image capture device then depends little on the height of the contoured lens 10 relative to the support 110. The display device 130 includes, for example, a screen adapted to display said scrolling pattern 150, 250. It is preferably a digital screen. Thus, the display device 130 is, for example, a backlit LCD screen which also acts as the light source for the device 100. This LCD screen is then adapted to scroll this scrolling pattern 150, 250 according to the said predetermined scrolling direction relative to said support 1 10. The scrolling pattern 150, 250 includes, for example, at least one dark RS band surrounded by two lighter RC bands, or one light RC band surrounded by two darker RS ​​bands. Preferably, it includes a plurality of alternating dark RS and light RC bands (see figures 3 to 12). Each band extends along a longitudinal axis. The light and dark bands displayed on the digital screen are preferably white and black. In other words, the light bands have a uniform display brightness close to 255, and the dark bands have a uniform display brightness close to 0, in RGB value. They preferably have identical widths. They also preferably have substantially straight and parallel edges. With the image capture device 120 focused on the support 1 10 or on the contoured lens 10 placed on it, at a distance from the display screen 130, the black and white bands of the pattern are blurred and the scrolling pattern 150, 250 seen through the contoured lens 10 then presents a continuous variation in brightness. More specifically, device 100 is preferably arranged so that the brightness variation of the scrolling pattern varies continuously from white to black with a substantially sinusoidal variation. In other words, on the image captured by the image capture device 120, the scrolling pattern 150, 250 exhibits a brightness that varies continuously between two extreme values ​​in a substantially sinusoidal manner, the two extreme values ​​being close to 0 for one and 255 for the other in RGB values. Figures 3 to 7 show a first type of scrolling pattern 150, comprising alternating black and white bands extending along a vertical axis in the image capture plane. Figures 8 to 12 show a second type of scrolling pattern 250, comprising alternating black and white bands extending along a horizontal axis in the image capture plane, i.e., in a direction orthogonal to the direction of the bands of the first type of scrolling pattern. 150. Regardless of the scrolling pattern considered, the scrolling direction in which the display device 130 is adapted to scroll the alternating black and white stripes is perpendicular to the longitudinal axis along which the stripes extend. In other words, the vertical bands scroll horizontally, and the horizontal bands scroll vertically, as shown in figures 3 to 7 on the one hand and 8 to 12 on the other. The 130 display device is also preferably suited to displaying one or more fixed patterns, for example a Hartmann matrix. Optionally, the device 100 may also include an additional display element with a fixed pattern, for example, a Hartmann matrix. This could be, for example, a transparent, non-backlit LCD screen. This additional display element is then placed between the support 1 10 and the display device 130. Of course, the various optical elements of this device 100, namely, the image capture device 120, the support 110 and the display device 130, as well as, where applicable, optional optical elements such as a telecentering lens or optical system and an additional display element of a fixed pattern, are centered on a common optical axis A1 (Figure 1) of the device 100. Device 100 also includes electronic and computer resources, here in the form of a computer 160, programmed to: - trigger the capture of each image of the cropped lens according to the scrolling of the pattern 150, 250 and - determine the geometric and / or optical characteristics of the desired cut-out lens 10 based on the plurality of image captures made and comparison of this geometric and / or optical characteristic with a corresponding desired characteristic. The computer 160 includes for this purpose in particular the said means of synchronization 140 of the plurality of image captures by the image capture device 120 and of the scrolling of the pattern 150, 250 produced by the display device 130 the said means of determination. The said electronic and computer means further include here a database 170 (figure 1) which the computer 160 can access in order to read certain information or save certain results. Method This device 100 allows the implementation of the method for verifying the contour and an optical characteristic of an ophthalmic lens cut according to the invention. This method includes the following steps: a) The cut-out ophthalmic lens is placed on the support 1 10, b) at least one image of this outlined ophthalmic lens is captured using the image capture device 120, c) a measured geometric characteristic of said cut-out ophthalmic lens 10 is determined from this image, d) at least one measured optical characteristic of this outlined ophthalmic lens 10 is determined in a frame of the image captured in step b), e) said measured geometric characteristic and the measured optical characteristic are compared to a predetermined desired ophthalmic lens model, comprising at least one desired geometric characteristic and a corresponding desired optical characteristic. In practice, prior to checking the cut-out lens 10, the operator retrieves information concerning the desired lens. More specifically, for example, each contoured lens 10 is associated with an identifier allowing consultation of the desired geometric and optical characteristics of the contoured lens. This identifier is called a "Job Ticket". The operator enters the Job Ticket number into computer 160, using the keypad or a barcode scanner. This number allows the computer to access a file associated with the cut-out lens 10 stored in database 170 (Figure 1). This file contains the desired geometric and optical characteristics for the contoured lens 10, including: - a desired outline, - desired power levels, - the desired orientations of the axes, - a desired position of the optical center, - a desired value for the half-interpupillary distance, - a desired value of the pupil height relative to the lower edge of the trimmed lens, i.e. the height of the optical center of the trimmed lens relative to the lower edge of the trimmed lens. We will distinguish in the following three different types of contoured lenses: - single-vision lenses, which have the same power over their entire surface, - bifocal or trifocal lenses, featuring a body with a first optical power and one or two pellets exhibiting second and / or third optical powers different from the first, - progressive lenses, which have continuously variable optical power between a distance vision zone and a near vision zone. Regardless of the type of lens being cut out, steps a), b) and c) can be carried out in the same way. The operator places the cut-out lens 10 to be checked on the support 1 10. He ensures that the cut-out lens is substantially centered on the support 1 10 so that it is within the image capture field of the image capture device 120. The operator triggers the capture of at least one initial image of this outlined ophthalmic lens 10. For the capture of this first image, the LCD screen forming the display device 130 is lit but displays no pattern. The display screen then has a uniform brightness. For example, it is entirely white. The captured image is transferred to the computer 160 which processes the image in such a way as to determine, from this image, the measured geometric characteristic(s) of the cut-out lens 10, for example a measured contour 20 of said cut-out ophthalmic lens 10. This measured contour 20 is determined in the image capture plane. Alternatively, the measured geometric characteristic of the contoured lens determined in step c) can be the relative position of two or three predetermined specific points of the contoured lens. It can also be one or more measurements of characteristic distances of this contoured lens. In step d), said measured optical characteristic of this contoured ophthalmic lens 10 comprises at least one of the following characteristics: - measured position of a measured optical center, - measured direction of a measured optical axis, - measured direction of a shade gradient of the outlined ophthalmic lens 10, - measured direction of a polarization axis of the ophthalmic lens cut out 10. Step d) is carried out in different ways depending on the type of lens trimmed 10 considered. When the cut-out lens 10 is a single-vision lens, in a first embodiment of step d), the operator or the computer 160 automatically triggers at least a second image capture of the cut-out lens 10, displaying behind this cut-out lens 10 relative to the image capture device the fixed pattern representing for example the Hartmann matrix. Thus, in step d), the second image captured by means of said image capture device is the image of the fixed pattern constituted by the Hartmann matrix through the cut-out ophthalmic lens 10, and said optical characteristic is determined as a function of this second image. This Hartmann matrix is ​​a matrix of points whose relative positions are known in the plane of display of the matrix. This Hartmann matrix can be displayed here by the display device 130. It then constitutes one of the patterns that this device is adapted to display. In practice, then, here the Hartmann matrix is ​​displayed on the LCD screen of the display device 130. Alternatively, the Hartmann matrix can also be displayed on the additional display element mentioned earlier. This second image is processed by computer 160 which identifies the points of the matrix on the second captured image and compares their relative positions on this second image to their relative positions in the display plane of the matrix. In the case where the Hartmann matrix is ​​displayed on the LCD screen of the display device 130, the image processing is adapted to take into account the defocusing of this screen. The computer 160 is also programmed to determine then, as a function of the deviation of the points of the Hartmann matrix on the image of the matrix captured through the cut-out lens with respect to the position of the points of this known matrix, the optical center of the cut-out lens 10 and an optical axis of the lens which is in practice here the axis of the cylinder (if it exists). The position of the points in this matrix is ​​determined, for example, by empty in device 100 by an image capture made without any lens placed on support 1 10. These measured optical characteristics (position of the optical center, orientation of the axis of the cylinder) of the cut-out ophthalmic lens are thus determined in the frame of the second captured image, which is identical to the frame of the first captured image in step b). According to a second embodiment of step d) in the case of a single-vision contoured lens, in a step d1) prior to step a), the contoured ophthalmic lens is placed in a lensometer and a mark indicating the optical center and / or the optical axis on said ophthalmic lens is placed on said contoured ophthalmic lens, and in a step d2) the image of this mark is identified on said first image captured in step b). In practice, the frontofocometer allows 3 points representing the optical center and the direction of the axis of the cylinder to be placed on the front face of the cut-out lens, which are easily identifiable by image processing. The measured optical characteristics of the cropped ophthalmic lens are obtained here directly in the coordinate system of the first image captured in step b). When the contoured lens 10 is a progressive lens, in step d), a plurality of images of the scrolling pattern 150, 250 displayed on said display device 130 are captured by means of said image capture device 120 through the contoured ophthalmic lens 10 and said optical characteristic is determined as a function of this plurality of images. Two examples of pluralities of captured images are shown in Figures 3 to 7 and 8 to 12, respectively. In what follows, the plurality of images shown in Figures 3 to 7 will be referred to as the first series of images, and the plurality of images shown in Figures 8 to 12 as the second series of images. Each plurality of images comprises a number m of images, here 5 images. In general, the scrolling pattern 150, 250 displayed by the display means 130 presents a predetermined spatial period. In the scrolling pattern examples 150, 250 shown in figures 3 to 7 and 8 to 12, the scrolling pattern 150, 250 includes alternating black and white bands of the same width, as described previously. The spatial period of each scrolling pattern 150, 250 is equal to the sum of the widths of a black band and a white band, i.e. twice the width of a band. Each image capture of said plurality of images counting m images by the image capture device 130 then corresponds preferably to the display of the scrolling pattern 150, 250 offset by a distance equal to 1 / m times the spatial period of this scrolling pattern 150, 250 with respect to the previous capture. In the examples shown in figures 3 to 7 and 8 to 12, each of the first and second series of images has 5 images, so each image corresponds to the display of the scrolling pattern 150, 250 offset by 1 / 5 times the spatial period of this scrolling pattern 150, 250. The said synchronization means of the computer 160 are programmed to synchronize the capture of each image of said plurality of images by the image capture device 120 and the scrolling of the scrolling pattern 150, 250 produced by the display device 130 so as to trigger a number m of image captures, the scrolling pattern 150, 250 being offset by a distance equal to 1 / m times the spatial period of this scrolling pattern 150, 250, according to the direction of scrolling, between two successive image captures. Once the m images of a series of images have been captured, these images are transmitted to computer 160 which is programmed to perform statistical processing of these images. More specifically, in step d), the computer 160 is programmed here to determine an AI-enhanced image of said ophthalmic lens outlined 10 by statistical processing of said plurality of images of the captured scrolling pattern 150, 250. In practice, here, said AI-enhanced image is determined from the calculation of the standard deviation of said plurality of images of the scrolling pattern 150, 250. Alternatively, the said enhanced image can be determined by other statistical calculations, such as calculating the variance of the plurality of captured images or calculating the maximum or minimum of each pixel over the plurality of captured images. In this AI-enhanced image, the scrolling pattern 150, 250 is invisible. The statistical processing thus makes the scrolling pattern 150, 250 disappear. In addition, on the AI-enhanced image, the outline of phase objects such as micro-etchings on the surface or in the volume of the contoured lens appear clearly. Thus, on the improved image, it is possible to precisely identify the image of the micro-engravings of the cut-out lens, which usually indicate the optical center or prism reference point, usually noted PRP, and the direction of the axes of this cut-out ophthalmic lens. Figure 13 shows, for example, one of the 50 circular micro-engravings used to determine the position of the optical center, or prism reference point PRP, of the cut-out lens 10 on the enhanced image IA. We can see that this micro-etching 50 is much more visible on the improved image than on the images captured by the image capture device 120 shown in figures 3 to 12. The computer 160 is thus programmed to identify on said AI enhanced image of said contoured ophthalmic lens 10 at least one of said micro-engravings and to deduce therefrom the optical characteristic(s) sought, in particular the position of the measured optical center and / or the direction of the measured axis of the cylinder of the contoured lens 10. When the cut-out lens 10 is bifocal or trifocal, it has dots of optical power different from that of the rest of the lens. Step d) is then carried out as with the progressive lens, by capturing at least a plurality of images of the pattern moving through the contoured lens 10 in a manner synchronized with the movement, as described previously. The statistical processing described previously is applied to this plurality of images in order to determine the enhanced image of the contoured lens 10. The computer 160 is then programmed to identify, on the enhanced image obtained, a contour of the disc(s) with optical power different from that of the rest of the ophthalmic lens of the bifocal or trifocal lens. The position of this disc(s) then constitutes the optical characteristic determined in step d). In addition, in general, it is possible to identify on the AI-enhanced image the measured contour 20 of the contoured lens 10 or coating defects of this contoured lens 10. The identification of the measured contour 20 of the cropped lens 10 on the improved image makes it possible to possibly complete the determination of the geometric characteristic carried out in step b). If the measured contour 20 has already been determined in step c), this identification on the AI-enhanced image allows for confirmation and potentially refinement of the measured contour determined in step b). Indeed, for some contoured lenses, determining the lens contour from the image captured in step b) is imprecise or difficult. This is the case, for example, with ophthalmic lenses with a polished glass finish. In the case where the geometric features determined in step c) do not include the measured contour 20, it is determined from the enhanced image. Alternatively, steps b) and c) described above can be performed in conjunction with step d). In this case, no images without a displayed pattern are captured. In step b), the image capture device captures images of the moving pattern. During the implementation of steps c) and d), the enhanced image is determined from the captured images, and the geometric and optical characteristics of the contoured lens are determined from this image. Specifically, the image of the measured contour of the contoured lens is identified on this enhanced image, and the measured contour is deduced from it. The measured optical characteristics of the contoured lens are determined from the identification, on the enhanced image, of the images of the micro-etchings of the contoured lens. Regardless of the lens type, identifying coating defects allows for quality control of the trimmed lens. Depending on the location of the defects, whether central or peripheral, the computer can be programmed to issue an alert signal indicating that the lens needs to be remanufactured. Regardless of the lens type, for contoured, tinted, gradient ophthalmic lenses, in addition to the lens prescription axis, the axis of the ophthalmic lens tint gradient can also be determined. This is done by determining the axis of the direction of brightness variation on the lens image recorded in step b) or step d). Similarly, for polarized contoured ophthalmic lenses, the polarization axis is also checked. This can be achieved for example by using the polarization of the LCD screen of the display device 130. The contoured lens 10 is rotated on or with the support 1 10 until the light intensity passing through the ophthalmic lens is close to zero, which means that the polarization axis of the contoured lens is orthogonal to the known polarization axis of the LCD screen. The lens support can be motorized to rotate the lens, or the lens can be rotated manually by the operator. The polarization axis is determined by interpolating measurements taken in different positions of the contoured lens. In step e), the practical task is to check the prescription of the lens, including the interpupillary distance, height, and axis (cylinder axis, gradient tint, and / or polarization) of the trimmed lens against the wearer's prescription. To this end, any centering and / or axis errors of the trimmed lens are determined. In step c), the geometric characteristics of the contoured lens 10, here its contour, were determined, and the optical characteristics of this contoured lens were determined in step d), in the reference frame of the image captured by the image capture device. Regardless of the type of contoured lens 10, the computer is programmed to compare the measured geometric feature and the measured optical feature of the contoured lens to a predetermined desired ophthalmic lens model, comprising at least one desired geometric feature and one desired optical feature corresponding to said measured geometric feature and measured optical feature. This model represents the desired lens. The said model of the desired ophthalmic lens is determined according to the desired geometric and optical characteristics for the contoured lens 10 contained in the file which the computer 160 accesses from the "Job Ticket". This model, an example of which is shown in Figure 2 in solid lines, includes for example the desired contour 30 for the lens, with the desired optical center COS at its desired position relative to the desired contour 30, and the orientation of the optical axes 32, 33 of the desired lens relative to the desired contour 30. This model also includes, optionally, a desired direction for the tint gradient of the lens and / or a desired direction for the polarization of this contoured lens. In general, at step e), the computer 160 is programmed to match the measured geometric feature(s) with their corresponding desired geometric feature. In this way, the contoured and desired lenses can be positioned relative to each other so that they overlap as closely as possible. More specifically, here, in step e), computer 160 is programmed to perform the following sub-steps: e1) superimpose the measured contour onto the desired contour, minimizing the difference between them. e2) determine the difference between the measured optical characteristic and the desired optical characteristic as a function of the superposition carried out in step e1). Step e1) allows the desired and measured optical characteristics to be placed in the same geometric reference frame linked to the cut-out lens, which is represented in Figure 2. An algorithm for superimposing the desired contour 20 and the measured contour 30 is described below. The desired contour 20 and measured contour 30 are two closed contours in 2 dimensions consisting of n points with coordinates (x, y) in a frame associated with each desired contour 20 and measured contour 30, whose origin (0, 0) is located inside this contour. The goal is to find the translation values ​​Tx and Ty and the rotation value Rz to apply to the measured contour 30 so that the errors between the desired contour 20 and the measured contour 30 having undergone these translations and rotations are as small as possible. The computer is programmed to calculate the center of gravity of each of the two contours, denoted in the sequence Cdg1 and Cdg2. The center of gravity of each desired contour 20 and measured 30 can be calculated by taking the barycenter of the triangles formed by the n points whose common vertex is the coordinate (0, 0) of the origin point of the coordinate system associated with the contour. Each center of gravity is then determined according to the formula: The computer is then programmed to recalculate the desired and measured contours of the lens in a reference frame centered on their center of gravity Cdg1, CDG2 respective. It is therefore a matter of subtracting from the coordinates of each point of the desired contours 30 and measured contours 20 the coordinates of the corresponding center of gravity Cdg1, Cdg2. It is then possible to superimpose the centers of gravity Cdg1 and Cdg2 of the two desired and measured contours. The values ​​of the translations Tx and Ty can be deduced from the difference between the coordinates of the two determined centers of gravity. Next, we proceed iteratively with an algorithm, an example of which is given below, to determine the rotation to be applied to the measured contour 20 to superimpose it on the desired contour 30. According to an example of this algorithm, the difference between the measured contour 20 and the desired contour 30 is quantified by summing the distances between the two contours for a predetermined number of angles distributed around the common center of gravity of the two contours. The number of angles is linked to the desired resolution, for example, less than or equal to the number of points within the corresponding contour. It is also possible to impose an angular step, for example, equal to one-tenth of a degree, between two angles for which the gap between the contours is evaluated, and to evaluate this gap by interpolation between the points of the contours closest to the corresponding imposed angles. The difference between the desired contour 30 and the measured contour 20 is thus determined for different values ​​of the rotation angle transforming the measured contour 20, and compared to a threshold value of deviation. When the calculated deviation is less than the said threshold deviation value, the corresponding rotation angle is retained to transform the measured contour 20. More precisely, we consider for example successively the rotations having as their center the common center of gravity Cdg1, Cdg2 of the two contours, and an angle of rotation Rz between a minimum value and a maximum value, for example between -Pi and Pi, with an increment of angle of rotation which takes increasingly smaller values. This increment value is, for example, initially equal to Pi / 8. The increment for the next iteration is decreased, for example divided by two or by a higher integer. As long as the increment value remains greater than the desired precision on the rotation angle, the computer calculates for each rotation angle Rz equal to the minimum value of the rotation angle plus an integer k times the angle increment, the difference between the desired contour and the contour transformed by this rotation. When this deviation becomes less than the threshold deviation value, the value of the rotation angle Rz is determined to be the value of the rotation angle tested during this iteration. It is also possible to predict that successive iterations will search for the minimum value of the difference between the two contours, and then, in the next iteration, recenter the maximum and minimum values ​​of the tested rotation angles to the rotation angle value for which the difference was found to be minimal. The increment for the next iteration is decreased, for example, halved or divided by a larger integer. With the desired contour 20 and measured contour 30 then superimposed as best as possible, it is possible to determine the difference between the desired optical center COS and the measured optical center COM. These differences are determined, for example, in a boxing reference frame (S, U, V) corresponding to the boxing frame of reference of the desired contour 30. The center S of this frame of reference is the geometric center of the boxing rectangle in which the desired contour 30 is included, and is called the boxing center. The axes of this boxing frame of reference are parallel to the sides of this rectangle. The difference between the desired optical center COS and the measured optical center COM thus allows us to determine the error on the half interpupillary distance E1 and the error on the height E2 of the optical center relative to the lower edge of the trimmed lens (figure 2). The error on the half interpupillary distance E1 is the coordinate along the axis U parallel to the shorter side of the boxing rectangle and the error on the height E2 of the optical center relative to the lower edge of the trimmed lens is the coordinate along the axis V parallel to the longer side of the boxing rectangle (figure 2). The angular difference between the axis 32, 33 of the desired lens and the axis 34, 35 of the measured lens gives access to an axis error E3 of the trimmed lens (figure 2). Similarly, computer 160 compares the measured axis of the brightness variation direction to the desired axis for the brightness variation. The axis error on the gradient hue can be determined as the difference between the measured axis of the brightness variation direction and the desired axis. For contoured polarized ophthalmic lenses, the computer 160 compares the direction of the measured polarization axis to the direction of the desired axis for the polarization of the contoured lens 10. The polarization axis error can be determined as the angle between the direction of the measured polarization axis and the direction of the desired polarization axis. Thus, in a step f), the computer 160 determines, based on the comparison made in step e), a parameter relating to the difference between said measured contour and said desired contour and a parameter relating to the difference between said measured optical characteristic and said desired optical characteristic. This parameter relating to the difference between said measured optical characteristic and said desired optical characteristic is here for example the value of the error determined between each measured optical characteristic and the corresponding desired optical characteristic. The parameter relating to the difference between said measured contour 20 and said desired contour 30 is for example the sum of the distances between the points of the measured contour 20 and the desired contour 30 when the two contours are superimposed. In step f), computer 160 is then programmed to compare said parameter relating to the difference between said measured contour 20 and said desired contour 30 and each parameter relating to the difference between said measured optical characteristic and said desired optical characteristic to tolerance threshold values ​​and determines based on this comparison a conformity indicator of the contoured ophthalmic lens 10. In practice, the computer is programmed to compare the errors to maximum permissible error values. The parameter relating to the difference between the desired contour and the measured contour is compared to a maximum permissible threshold value for that parameter. The conformity indicator of the contoured lens 10 with respect to the desired optical characteristics is deduced. When the determined errors and the parameter relating to the difference between the desired contour 20 and the measured contour 30 are less than the maximum error values ​​and maximum permissible threshold value mentioned previously, the corresponding trimmed lens is declared compliant with the desired lens. The indicator shows that the trimmed lens is compliant. The maximum permissible error values ​​can advantageously be modulated according to the desired optical characteristics of the lens and the standards of the countries in which the pair of glasses will be used. Preferably, the determination of the conformity of each lens is carried out independently for the right lens and the left lens intended for the same frame. Then, in a step g), the computer 160 determines, based on the comparison made in step e), a parameter relating to the difference between the said optical characteristics measured for a right lens and a left lens intended for said mount. Computer 160 then compares said parameter relating to the difference between said optical characteristics measured for a right lens and a left lens intended for said frame to a threshold tolerance value and a conformity indicator of the right and left contoured ophthalmic lenses is determined based on this comparison. We therefore determine here the errors described above for each of the two lenses right and left intended to be mounted in the same mount, then we compare these errors with each other. The difference between the errors determined for the right and left lenses is compared to the corresponding tolerance threshold value. The conformity indicator shows that the right and left lenses are compliant with each other if the difference between these errors remains below the corresponding tolerance threshold value. Advantageously, corresponding overall errors can also be deduced from the above when both the right and left contoured lenses are used in the associated frame. For example, an error in the total pupillary distance, a height difference between the right and left contoured lenses, and an axis difference between the right and left contoured lenses can be determined. When the determined errors and the parameter relating to the difference between the desired contour 20 and the measured contour 30 exceed the maximum error values ​​and maximum permissible threshold value mentioned previously, the corresponding trimmed lens 10 is declared non-compliant with the desired lens. The indicator shows that the trimmed lens is non-compliant. The results, lens error and conformity, can be recorded in database 170 for archiving and / or analysis. In the event that the contoured lens 10 is declared non-compliant, the device 100 can, for example, relaunch a manufacturing order for this contoured lens. In the event that the trimmed lens 10 is declared compliant, it is for example shipped to the customer accompanied by a quality control certificate. In the event of a return of a trimmed lens by a dissatisfied customer, it is checked by device 100 and the results of this check are compared to those obtained before the trimmed lenses were sent to the customer. The verification by device 100 and the method described here of an identical predetermined contoured lens 10 manufactured at regular intervals on a production line also makes it possible to verify that the contouring tools, upstream of the verification device, do not have any defects or wear. If a device 100 is used, equipped with a suitable support for fixing the frame with its two ophthalmic lenses, it is also possible to directly check the interpupillary distance, the heights of the optical centers relative to the lower edge of the corresponding lens, and the axes of the ophthalmic lenses with cut edges, mounted in the frame. Here, we have described the case where the measured and desired contours are positioned relative to each other by minimizing the gap between the two contours, and then the gap between the optical characteristics is quantified based on this relative positioning of the measured and desired contours. Alternatively, we can consider that the measured and desired contours of the trimmed lens are positioned relative to each other by minimizing the gap between the measured and desired optical characteristics, for example, by minimizing the distance between the measured and desired optical centers and minimizing the angular gap between the measured and desired cylinder axes. The gap between the measured and desired contours is then quantified based on this relative positioning.

Claims

------28 / 07 / 2016------(OCR) Page 1 of 4 pages Claims 1. A method for examining at least one geometric characteristic and one optical characteristic of an integrated ophthalmic lens (10) composed of the following steps: a) The integrated ophthalmic lens (10) is placed on a holder (110). b) At least one image of this integrated ophthalmic lens (10) is captured. c) On the basis of this image, the measured geometric characteristic of such integrated ophthalmic lens (10) is identified. d) At least one measured optical characteristic of this integrated ophthalmic lens (10) is identified in the coordinates of the image captured in step b). e) Such measured geometric characteristic relating to the measured optical characteristic is compared with a predefined desired ophthalmic lens model composed of at least one corresponding desired geometric characteristic and one corresponding desired optical characteristic. 2.

3. In either of the methods under Claims 1 and 2, where in step c) such an optical characteristic is measured, incorporating the position of the optical center (COM) and / or direction of the optical axis (34,35) of the edged optical lens (10), the following sub-steps are performed: d1) Prior to step c) the edged optical lens (10) is placed in the meter lens and a mark is made on the edged optical lens (10). Such mark indicates the optical center and / or direction of the optical axis on the edged optical lens (10). d2) An image of this mark is indicated in the image captured in step b).In one of the methods claimed under claims 1 and 2, where the holder (110) of the beveled optical lens (10) is placed between the capture device (120) suitable for capturing the image of this optical lens in step b) and the device (130) for displaying the fixed pattern in step d), by means of such capture device (120), an image of this fixed pattern is captured through the beveled optical lens (10), and such optical characteristics are identified based on this image. Page 2 of number 4, page 5. In one of the methods claimed under claims 1 and 2, where the holder (110) of the beveled optical lens (10) is placed between the capture device (120) suitable for capturing the image of this optical lens in step b) and the device (130) for displaying the sliding pattern (150,250) in step d), by means of such capture device (120), a number of images of the sliding pattern (150,250) are captured through the beveled optical lens (10), and such optical characteristics are identified based on this number of images.6.The method as requested in claim 5, in which step d) the slide pattern (150,250) is rendered by the rendering path (130) with a predetermined interval and a number of such images comprised of m images, each capture of such images by the capture device (120) corresponds to the rendering of the slide pattern (150,250) shifted by a distance equal to 1 / m times the interval of this slide pattern (150,250) relative to the previous capture.

7. The method as requested in claim 6, in which step d) the enhanced image (IA) of such edged optical lens (10) is identified by statistical processing of such images of the slide pattern (150,250) through the edged optical lens (10).8.The method as requested under claim 7 in which step d) in the improved image (IA) of the edged ophthalmic lens (10) an image of at least one of the following components is indicated - engraving (50) made on the surface of the edged ophthalmic lens (10) or in the volume of the edged ophthalmic lens (10) - measured outline (20) of the edged ophthalmic lens (10) - outline of an area of ​​optical power different from that of the rest of the edged ophthalmic lens (10) - defect in the coating (multi-layer) of the edged ophthalmic lens (10)9.In any of the methods proposed under the preceding claim, in step c) the measured geometric characteristics of the measured outline (20) of the edged lens (10) and in step e) the desired ophthalmic lens model incorporating the desired outline (30) are performed, the following sub-steps are performed: el) the measured outline (20) is superimposed on the desired outline (30) by minimizing the mismatch therein. Page 3 of 4. e2) the mismatch between the measured optical characteristics and the desired optical characteristics is identified based on the superposition obtained in step el)10. In any of the methods proposed under the preceding claim, in step d) the measured optical characteristics of the edged lens (10) are superimposed. At least one of the following characteristics—the position of the measured optical center (COM)—the direction of the measured optical axis (34,35)—the measured direction of the tonal gradient of the edged ophthalmic lens (10)—the measured direction of the polarization axis of the edged ophthalmic lens (10) 11.

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14. According to one of the methods proposed in the prior claim, in step g), based on the comparison made in step e, the parameters relating to the mismatch between the measured optical characteristics are identified for the right and left lenses intended for the structure.

14. According to one of the methods proposed in the prior claim, in step g), such parameters relating to the mismatch between the measured optical characteristics are compared for the right and left lenses intended for the structure to acceptable threshold values, and based on this comparison, the indicator of conformity of the right and left contoured lenses is identified on page 4 of page 15.A device for examining at least one geometric and / or optical characteristic of an edged optical lens (10) that is assembled with: - a holder (110) for such edged lens (10); - on one side of this holder (110) an image capture device (120); - on the other side of this holder (110) a display device (130) suitable for displaying at least one slide pattern (150,250) and for making this slide pattern (150,250) slide in at least one predetermined slide direction relative to the said holder (110); - a path (140) for synchronizing a number of image captures by the image capture device (120) and the slide pattern (150,250) performed by the display device (130); - a path for identifying such geometric and / or optical characteristic of the edged optical lens (10) based on a number of captured images and for comparing this geometric and / or optical characteristic with the corresponding desired characteristic.16.An apparatus as claimed in any of the preceding claims in which such sliding pattern(150,250) is composed of alternating black and white bars and in which the capture device(120) is focused near the mount(110) at a distance from such sliding pattern(150,250)------------;.