Essilor International (compagnie Generale D'optique)

Essilor International

Essilor International (compagnie General D'optique)

Laurent Guillermin

Sylvaine Millet

Michel Nauche

Fabien Divo

Xavier Levecq

Ludovic Jouard

James Thepot

Patrick Horel

Ren&eacute; Farcy

Emmanuel Almeras

Florent Guirriec

Henri Hougas

Process for plotting the shape of a contour () of a previously machined ophthalmic lens (), which comprises the steps of:

Process for plotting the shape of a contour of a previously machined ophthalmic lens

The invention relates to a method for carrying out the precise trimming of a lens (), whereby the lens is held between two clamping plates () in a given position and the grinding of the periphery of the lens () is controlled along a trajectory, the last programmed part of which corresponds to the form () desired for the lens. The method comprises a first scanning under weak clamping conditions of a number of points on one face of the lens with scanning of the coordinates of the points (), forming the trace on said face of the mounting circle, a second scanning, with a significant level of clamping which corresponds to that used on trimming the lens of a second number of points on said face of the lens, an approximate mathematical representation of the face of the lens for each of the two clamping conditions, a calculation of the coordinates for the deformation of the contour of the lens on said face of the lens in the second clamping condition to correct the last programmed part of the grinding trajectory.

Method for trimming a spectacle lens

Device comprising in combination: elements for detecting () characteristics of a lens; elements for integrating characteristics representing a patient's morphology; a support () of the mobile lens along a predetermined trajectory between a first measuring position and a loading position; grinding elements (); and elements forming a gripping and clamping clip () for transporting the lens from the loading position to the grinding position.

Automatic or semi-automatic device for trimming an ophthalmic lens

Process for bevelling at least one edge () of an optical face () of an ophthalmic lens (), in which the successive curvatures of the optical face () are plotted in the vicinity of and along the edge () to be bevelled. The edge () to be bevelled is scanned with a flat light beam () forming a linear light spot () on the optical face (), an image of the light spot () is simultaneously formed on optical reception elements (), the successive curvatures of the optical face () in the vicinity of the edge () are deduced from the successive positions of this image. This process includes a bevelling stage. Then the lens () is rotated about an axis (A), is brought into contact by its edge () with a bevelling tool, and the relative positioning of the lens () and of the tool is controlled according to the plots produced.

Process for bevelling an ohthalmic lens including a plotting stage without contact

Process for grinding the rim of an ophthalmic lens that has two opposite faces, following a predetermined contour corresponding to that of a ring of a spectacle frame in which the lens is intended to be mounted, the contour being delimited on each of the faces by an edge, and the process includes a plotting stage in which the three-dimensional shape of at least one of the edges is plotted. In the plotting stage, the edge is scanned on the illuminated face of lens using a light beam forming a light spot on the face, the successive positions of an image of the light spot are plotted simultaneously on optical reception elements pointing towards the light spot, and the three-dimensional shape of the edge is deduced from the plots made, machining of the lens being carried out according to the plot or plots.

Process for grinding an ophthalmic lens, including a plotting operation without contact

A device for automatically detecting characteristics of an ophthalmic lens includes a support receiving the lens, an illumination system and an analysis system. The optics of the illumination system define two alternate optical paths, one of which passes through a mask forming a Hartmann matrix.

Device for automatically detecting characteristics of an ophthalmic lens and an automatic device for fitting a centering and drive peg incorporating it

An optical non-contact method of reading the three-dimensional shape of a profile in accordance with the luminous section principle consists of scanning the profile with a plane light beam intersecting the profile transversely, simultaneously reading the trace of the plane light beam on the profile by means of an optical receiver having an optical pointing axis at a constant non-zero pointing angle to the light beam at a series of positions along the profile, and deducing the three-dimensional shape of the profile from the readings effected at these various positions. On each reading, the light beam whose trace on the profile is read by the optical receiver is chosen from a plurality of predefined light beams which can be activated alternately. The non-contact optical reading method is particularly suitable for reading the three-dimensional shape of the inside edge of a spectacle frame rim, known as the bezel. A specific device is used to implement the method in this particular application.

Optical method of reading the shape of a profile and application thereof to reading the inside edge of a spectacle frame rim

A method is disclosed of mounting a lens in either rim or surround of a spectacle frame in which each rim or surround has a rigid part and a filament which extends from one end of the rigid part to the other. The curvature of the rigid part is systematically taken into account over the portion of the trajectory of the necessary groove that corresponds to the rigid part concerned of the spectacle frame. Applications include corresponding spectacle frames.

Method of determining the trajectory of the groove to be machined in the edge of a lens to be fitted to a &ldquo;metal supra&rdquo; type spectacle frame

Designed to be fitted to an ophthalmic lens grinding machine to be calibrated instead of an ophthalmic lens, a calibration template is in the general form of a disk with a circular contour over at least part of its perimeter. Its contour forms two localized angular points circumscribed by a common circumference and having a relative angular offset.

Template for calibrating an ophthalmic lens grinding machine, and

A calibration gage for calibrating a device for reading off the contours of eyeglass frames is designed to be fitted to the contour reading off device to be calibrated in place of an eyeglass frame. It includes a plate with at least two ribs projecting from it. The ribs are generally parallel to each other in a first direction and spaced from each other in a second direction. By reading off the known dimensions between their inside and outside flanks, it is possible to determine some parameters of the contour reading off device.

Calibration gage for calibrating a device for reading off eyeglass frame

A machine for grinding ophthalmic lenses includes a motor driven grinding wheel, a swinging head frame for holding ophthalmic lens and rotating the lenses into and out of contact with the grinding wheel, and a veneer positively connected to the swinging head frame by a positive linkage to prevent separation of the swinging head frame from the controlling veneer and thereby avoid the introduction of errors into the position of the lens relative to the control position of the veneer.

Growing community of inventors

Paris, France

Laurent Guillermin