Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Patent
1998-03-09
1999-08-31
Manuel, George
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
A61B 314
Patent
active
059460741
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns the operations that a practitioner must execute prior to the machining that it is necessary to apply to a spectacles lens to match the contour of the latter to that of one of the rims or surrounds of the spectacles frame chosen by a patient.
In particular, it is important to center the spectacles lens relative to the rim or surround of the spectacles frame to which the lens is to be fitted and to apply to it a member referred to hereinafter for convenience only as a gripping member suitable for fitting it afterwards into a grinding machine.
These operations are usually carried out by means of the same apparatus, commonly called a centeringpositioning device, including a plate for receiving the spectacles lens to be processed and a positioning device arranged above the plate for positioning a gripping member on the spectacles lens.
For the gripping member to be positioned correctly the spectacles lens must first be "centered".
In other words, it must be positioned correctly relative to the spectacles frame rim or surround to which the lens is to be fitted.
To this end there is usually provided a screen for displaying an image of the spectacles lens and an image of the spectacles frame rim or surround to which the lens is to be fitted.
This is the case in the French patent published under the number 2 188 182, for example.
In the above French patent the screen is merely a piece of frosted grass which serves as a plate for the spectacles lens and on which is superposed by projection an image of the spectacles frame rim or surround to which the lens is to be fitted.
Providing an electronic screen on which an image of the spectacles lens and an image of the rim or surround of the spectacles frame to which the lens is to be fitted can be superposed is known in itself, in particular from the French patent published under the number 2 547 930.
In all cases the characteristics of the patient must be taken into account.
To be more precise, these are their pupillary distance, or half this distance, and the height of their pupils relative to the bottom of the spectacles frame rims or surrounds when the frame is being worn, commonly known as the mounting height.
This pupillary distance and this mounting height have for many years been measured using particular devices, namely a pupillometer for the pupillary distance and a ruler for the mounting height, and these devices are still frequently used today.
The corresponding measurements must therefore be "entered" into the centering-positioning device, with the attendant risk of error in the necessary manipulations.
It has therefore previously been proposed to make direct use in a centering-positioning device of the above kind of a photograph of the patient wearing the spectacles frame they have chosen and to measure the pupillary distance and the mounting height required from this photograph.
However, for obvious practical reason, the photograph cannot be life size and a formatting problem arises, which can itself lead to errors.
This problem is accentuated in that there is in practise no frame of reference for interpreting the photograph.
It has recently been proposed, in the French utility application published under the number 2 690 834 and in the French patent application published under the number 2 690 832 concerning the same subject matter, to computerize the measurement of the characteristics of a patient using an image of the latter provided by any kind of imaging device and in which the patient is shown wearing the spectacles frame in question, so that each of the spectacles lenses to be fitted can be centered relative to the rims or surrounds of the frame by calculation.
However, neither the above utility certificate application nor the above patent application provides any connection to a positioning device, i.e. to a device for positioning a gripping member.
A general object of the present invention is to provide an arrangement which, by virtue of a connection of the above kind, provides a satisfactory solution to the problems
REFERENCES:
patent: 4730260 (1988-03-01), Mori et al.
patent: 4845641 (1989-07-01), Ninomiya et al.
patent: 4852184 (1989-07-01), Tamura et al.
Joncour Christian
Massart Christian
Essilor International "Compagnie Generale d'Optique"
Manuel George
LandOfFree
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