Patent Description:
The lifetime of spectacle lenses includes different portions, for instance when it is a semi-finished lens, then a finished lens, then a trimmed lens and then when it is mounted in the frame of a pair of spectacles. Relevant prior art can be found in <CIT>.

The invention is directed to the monitoring of a spectacle lens during at least one portion of its lifetime in a way that is accurate and reliable while being simple and convenient.

The invention accordingly provides a method according to independent claim <NUM> for monitoring a spectacle lens. Preferred embodiments are described in the dependent claims.

Because the support is transparent (invisible or semi-visible), the support does not disturb the wearer of the spectacles in which is included this lens. Because the support is readable by an external tool, the reading of the support is accurate and reliable while being simple and convenient; and consequently the monitoring based on the data related to the spectacle lens is accurate and reliable while being simple and efficient.

By transparent is meant that the support does not impact significatively the local diffusion of the lens. For example a haze value in an area comprising the support is increase by less than <NUM>, preferably less than <NUM> or even <NUM> when compared to an area of the lens that does not comprise the support, when the measured area is about <NUM> or <NUM> times greater than the support, or according to alternative equivalent measurement of the haze value. Further, by transparent is also meant that the support does not reduce the transmission value by more than <NUM>% of the transmission value of a part of the lens without said support.

It is noted that the additional features of dependent claim <NUM> relate to the side where the spectacle lens is handled while the features of independent claim <NUM> are directed to the side where data related to the spectacle lens is handled.

The description of the invention continues now with a detailed description of preferred embodiments given hereinafter by way of non-limiting illustration and with reference to the appended drawings. In the drawings:.

<FIG> illustrates schematically the lifetime of a spectacle lens <NUM>, in chronologic order from left to right, as shown by the arrow at the right.

In a first portion <NUM> of the lifetime, the spectacle lens <NUM> is in the form of a semi-finished lens (SF) having a circular contour. One of the main faces, for instance the front face, is finished and the other main face, in this instance the rear face, is unfinished.

Alternatively, the semi-finished lens has no finished main face and/or has a contour which is not circular.

In the following portion <NUM> of the lifetime, the spectacle lens is in the form of a finished lens (F). Both main faces of the spectacle lens <NUM> are finished. Between portion <NUM> and portion <NUM>, the rear face of the lens has been machined so as to have a shape giving to the spectacle lens <NUM> the desired optical properties such as spherical power, cylindrical power and/or addition. In portion <NUM>, the spectacle lens <NUM> has the same circular contour as in portion <NUM>.

In the following portion <NUM> of the lifetime, the spectacle lens <NUM> is in the form of a trimmed lens (T) having a contour in accordance with the shape of the frame in which the spectacle lens <NUM> is to be mounted. Between portion <NUM> and portion <NUM>, the edge of the lens has been trimmed for instance by a grinding station.

In the following portion <NUM> of the lifetime, the spectacle lens <NUM> is in the same form as in portion <NUM> but is mounted in a frame (MF) of a pair of spectacles <NUM>.

The other spectacle lens <NUM> mounted in the frame <NUM> of the pair of spectacles <NUM> has a lifetime similar to the lifetime of the spectacle lens <NUM>.

Generally speaking, the description given below in relation to spectacle lens <NUM> applies also to spectacle lens <NUM>.

An identifier <NUM> (here an alphanumeric sequence, see <FIG>) that is unique to spectacle lens <NUM> has been allocated to spectacle lens <NUM>.

The identifier <NUM> is included in a support <NUM> incorporated in the spectacle lens <NUM>. The support <NUM> is readable by an external reading tool for retrieving the identifier <NUM>. Here, the external tool is a smartphone <NUM>.

A computer system <NUM> remotely accessible by the smartphone <NUM> includes an entry point <NUM>, a data base <NUM>, a data base manager <NUM> and a navigation manager <NUM>.

The entry point <NUM> includes an interactive managing routine for updating a monitoring variable <NUM> having a current value representative of a current one of the portions <NUM> to <NUM> of the lifetime of the spectacle <NUM>.

The data base <NUM> has a plurality of sections <NUM> to <NUM> each configured for containing data representative of current physical parameters of spectacle lens <NUM>. The data base <NUM> may also contain other parameters and/or data, for instance the commercial name of the spectacle lens <NUM> and/or the name of the owner of the spectacle lens <NUM>.

It is understood that sections <NUM> to <NUM> does not relate to the physical arrangement of the data in the database <NUM> but to the capacity of the database <NUM> and the database manager <NUM> to retrieve and arrange data according to sections <NUM> to <NUM>.

Section <NUM> is specific to portion <NUM> of the lifetime of spectacle lens <NUM>. Section <NUM> is specific to portion <NUM>. Section <NUM> is specific to portion <NUM>. Section <NUM> is specific to portion <NUM>.

For monitoring the spectacle lens <NUM> during portions <NUM> to <NUM> of its lifetime, the following steps are carried out at at least one moment of the lifetime.

On the side of the person handling spectacle lens <NUM>, the support <NUM> is read with the smartphone <NUM> for retrieving the identifier <NUM>, the entry point <NUM> is accessed with the identifier <NUM>, an interactive exchange is conducted with the interactive managing routine of the entry point <NUM> which accordingly updates if needed the current value of the monitoring variable <NUM>, and the data base <NUM> can then be accessed by this person through the data base manager <NUM> which selectively provides access to at least one of the sections <NUM> to <NUM> according to the current value of the monitoring variable <NUM>.

On the side of the computer system <NUM>, the same steps are viewed as follows: a request for access including the identifier <NUM> retrieved from the support <NUM> with the smartphone <NUM> is received by the entry point <NUM>, in response the interactive managing routine of the entry point <NUM> is carried out for updating the monitoring variable <NUM> if needed, then access is selectively provided by the data base manager <NUM> to at least one of the sections <NUM> to <NUM> according to the current value of the monitoring variable <NUM>.

The received request issued from a requester may include a variable related to the nature of the requester, and the data sent back toward the requester may depend both on the identifier and on the nature of the requester.

Here, the data base section <NUM> included in the data base <NUM> for the mounted-in-a-frame portion <NUM> of the lifetime of the spectacle lens <NUM> contains data representative of optical properties of spectacle lens <NUM>.

These optical properties are at least one of a spherical power and a cylindrical power.

The data base section <NUM> also contains data representative of physical parameters in relation to servicing of the spectacle lens <NUM>, information representative of optical properties of the pair of spectacles <NUM> in which is mounted the spectacle lens <NUM>, and/or data representative of optical properties of the other spectacle lens <NUM> in the pair of spectacles <NUM>.

The method of monitoring spectacle lens <NUM> just described is very useful to the different actors around the spectacle lens <NUM>.

The owner of the pair of spectacles <NUM> can very easily and conveniently benefits of the data stored in the data base <NUM>.

The optical properties of the spectacle lens can be useful to the user or to an Eye Care Professional (ECP) for retrieving the current prescription and/or other personal features characteristic of the user, without needing a specific search or enquiry or even any optometric measurement. For example, the ECP or the wearer can easily access to the current prescription, a possible progressive design already used for defining the optical surface of the current lens, or even mounting parameters, used for mounting the lenses on a frame, such inter-pupillar distance or pantoscopic angle.

This is the same for the optical properties of the pair of spectacles <NUM> and for the optical properties of the other spectacle lens <NUM>. For instance if spectacle lens <NUM> is so damaged that reading support <NUM> is no longer possible, but spectacle lens <NUM> is still available and its support <NUM> still readable, data in relation to spectacle lens <NUM> can be so gathered.

Such data can be entered in the data base <NUM> very easily and conveniently by the manufacturer of the spectacle lens, by the optician having assembled the pair of spectacles <NUM> or by the owner of the pair of spectacles <NUM>.

The data representative of physical parameters in relation to servicing of the spectacle lens <NUM> can be very useful to the optician and to the user for optimising the maintenance of the spectacle lens <NUM>.

Such data can be entered in the data base <NUM> by the manufacturer of the spectacle lens at the appropriate time that can be easily determined by the current value of the monitoring variable <NUM>.

Here, the data base sections <NUM> to <NUM> included in the data base <NUM> for the not-yet-mounted-in-a-frame portions <NUM> to <NUM> of the lifetime of the spectacle lens <NUM> contain data representative of physical parameters in relation to manufacturing of the spectacle lens <NUM>, for instance physical parameters in relation to the step of machining the unfinished face carried out between portions <NUM> and <NUM> or in relation to the edge trimming step carried out between portions <NUM> and <NUM>.

The data base sections <NUM> to <NUM> can also be useful for tracking and traceability in plants or for quality analysis in case of damage during use or other traceability application.

Certain data related to spectacle lens <NUM> is initially provided in database <NUM>, before or after having incorporated support <NUM> into spectacle lens <NUM>.

Further data related to spectacle lens <NUM> is optionally received and added in the database <NUM> at different moments, for instance before the step of incorporating support <NUM> into spectacle lens <NUM> or after having sent data retrieved from database <NUM> to a requester having issued a request including at least part of identifier <NUM>.

As is apparent on <FIG>, the step of incorporating the support <NUM> into the spectacle lens <NUM> is carried out at a time at which the spectacle lens is not mounted in a frame such as frame <NUM>; and the support <NUM> is incorporated in a location of the spectacle lens <NUM> selected to still belong to the spectacle lens <NUM> when the spectacle lens <NUM> is mounted in a frame such as frame <NUM>.

It should be noted in this respect that in <FIG>, the dashed line <NUM> in portions <NUM> and <NUM> shows the expected contour of the spectacle lens <NUM> after edging or trimming, that is from portion <NUM> on. Support <NUM> is within dashed line <NUM>.

In the embodiment shown on <FIG>, the support <NUM> is a reflective-transmissive pattern <NUM> formed on the front face of the spectacle lens <NUM>, visible on the side of (in other words: visible facing) the front face.

The pattern <NUM> was formed when manufacturing the spectacle lens <NUM> in the form of a semi-finished lens, that is prior to portion <NUM>.

The pattern <NUM> is formed by a plurality of dots, here square modules, having varying reflective-transmissive properties. Certain dots have the same reflective-transmissive properties as the rest of the surface of the front face of the spectacle lens <NUM>. Other dots have predetermined reflective-transmissive properties that are different from the reflective-transmissive properties of the rest of the surface of the front face of the spectacle lens <NUM>. The difference of reflective-transmissive properties is selected so that the dots having the predetermined different properties are visible on the side of the front face, that is by reflection.

According to the nature of the difference (more or less reflective than the rest of the surface), the dots having the predetermined difference are seen either as clear on a dark background (for example with a difference of reflection ranging from <NUM>% or less on the rest of the surface to <NUM>% or <NUM>% or even <NUM>% of reflection for the dots having predetermined different properties) or dark on a clear background (for example with a difference of reflection ranging from about <NUM>% on the rest of the surface to <NUM>% or even <NUM>% of reflection, with a change of chroma and hue for the dots having predetermined different properties).

In those two cases, the difference in reflective properties are important, with a factor of <NUM> to <NUM> for the first case, typically clear lenses with an antireflective stack, or with a factor of at least <NUM> combined with a change of chroma and hue for the second case, typically on mirror lenses, which lead to a contrast between the two types of dots strong enough to be detected easily using a smartphone or any simple embedded camera facing the front face.

The difference in transmissive properties are comparatively much smaller; in the first case, the difference in transmitted light accounts for less than a factor of <NUM>: <NUM>% or <NUM>% or <NUM>% of light transmission in the dots with different properties vs <NUM>% of transmission for the rest of the surface. In the second case, the difference in transmitted light accounts for a factor of less than <NUM>: <NUM>% or <NUM>% of light transmission in the dots with different properties vs <NUM>% of transmission for the rest of the surface.

Thus, using this technology, the pattern <NUM> has a high contrast in reflection, enabling it to be read easily when read from the front face, while having a low contrast in transmission, enabling it to be invisible or at least hardly visible and un-perturbing for the wearer of the spectacle glasses, when seen from the rear face.

In such a way, the pattern does not induce notable diffusion of light for the light reaching the wearer's eyes, eg in transmission, and it can thus be considered as transparent.

An exemplary method for measuring the impact of the pattern on diffusion is to measure the haze value in an area comprising the marking.

Haze value is measured by light transmission measurement using the Haze-Guard Plus© haze meter from BYK-Gardner (a color difference meter) according to the method of ASTM D1003-<NUM>. All references to "haze" values in this application are by this standard. The instrument is first calibrated according to the manufacturer's instructions. Next, the sample is placed on the transmission light beam of the precalibrated meter and the haze value is recorded.

It is useful to know that for the specific haze-guard plus© used by the inventors, the measuring spot used by the haze-guard plus© is a spot having a diameter of about <NUM>. Comparatively, in the embodiments of the invention that were used for haze measurement, the pattern is a square with a side of about <NUM>. Accordingly, what is measured is the impact on haze of a <NUM>*<NUM> matrix in a Pi(<NUM>)<NUM> area. The ratio of the measured area with regard to the pattern is thus of about <NUM>.

Further, a mean transmission value in the same area measured by the hazeguard plus© has been done.

According to the measurement methodology explained above, the following experiment have been realised:.

Before engraving the pattern, the measured haze is of <NUM> and the transmission is of <NUM>%.

After engraving a <NUM>*<NUM> pattern according to the invention, the measured haze is of <NUM> and the transmission <NUM>%.

After engraving a <NUM>*<NUM> pattern using a laser engraving which locally removes all the AR material and removes part of the hard coat, the measured haze is of <NUM> and the transmission <NUM>%.

As can be understood, the engraved lens <NUM> is not according to the invention as the impact of this specific support induces too much haze.

In particular, the term transparent, according to the invention means that the impact of the support on haze, measure in an area greater than the support by a factor of <NUM>, is smaller than <NUM>, preferably smaller than <NUM>, and most preferably smaller than <NUM>.

The person skilled in the art, knowing the experimental measurements above, can easily deduce, using a limited amount of experiments, an understanding of the word "transparent" according to the invention, even when measuring haze values with area ratio between the measured area and the support area widely different than the one presented above, for example, when measuring the haze of the support only, or when using a haze measurement with a measuring spot of <NUM> in diameter and measuring a <NUM>*<NUM> or <NUM>*<NUM> pattern.

This property of not disturbing the wearer can be further enhanced by positioning the pattern in a zone of the lens not often used by the wearer, such as the top temporal corner of each eyeglass.

Such large differences of reflective properties, from a factor <NUM> to a factor <NUM>, and low differences in transmissive properties, are selected so that the pattern <NUM> is not visible or hardly visible on the side of the rear face, that is by transmission. The wearer of the pair of spectacles <NUM> is thus not disturbed by the pattern <NUM>.

The pattern <NUM> can be incorporated into the spectacle lens <NUM> for instance by forming the dots having the different reflective-transmissive properties by locally modifying an interferential multicoat stack, that is by removing certain layers of the stack.

For instance, the spectacle glass <NUM> includes a substrate covered by such an interferential multicoat stack covering the substrate on the front face. The multicoat stack includes successively, from the substrate to front face, the following layers:.

The coating formed by this multicoat stack creates an interferential effect having a reflection coefficient less than <NUM>%, for instance <NUM> to <NUM>%.

The pattern <NUM> is formed by a plurality of punctual gaps of at least one layer of this interferential coating. Here the punctual gaps result from local irradiation by a laser beam ablating the top layer (number <NUM>) and stopped or almost stopped by the layer below (number <NUM>) which has absorbing properties at the wavelength of the laser beam.

The punctual gaps resulting from the ablation of the top layer (number <NUM>) have a reflection coefficient close to <NUM>%, more precisely between <NUM> and <NUM>%.

The pattern <NUM> of this example thus appears to an observer facing the front face of the spectacle glass as clear on a dark background.

Further details on a method of making a mark that can be used to make the pattern <NUM> can be found in <CIT>.

In the drawn embodiment, the pattern <NUM> forms a two-dimensional barcode comprising a plurality of modules in a juxtaposed matrix arrangement.

The plurality of modules includes, for encoding the identifier <NUM> according to a binary language, modules of a first type each formed by a dot having the different reflective-transmissive properties, and modules of a second type having the same reflective-transmissive properties as the rest of the front surface. Each dot or module of the first type is formed by a plurality of punctual gaps.

For instance, each dot or module of the first type is formed as a matrix having seven lines and seven columns of overlapping punctual gaps.

Generally speaking, a two-dimensional barcode including 21x21 modules can encode up to <NUM> alphanumerical characters. Each module has a square form having a side length of about <NUM>. The pattern <NUM> thus forms a square having a side length of about <NUM> x <NUM> = <NUM>.

The step of reading the support <NUM> with the smartphone <NUM> for retrieving the identifier <NUM> is carried out by taking a photograph or video of pattern <NUM>. The photograph or video is then analyzed for retrieving the identifier <NUM>.

The analysis of the photograph or video is performed directly that is by the smartphone <NUM>, as shown on <FIG>, thanks to a dedicated application.

Alternatively, the analysis of the photograph or video is performed elsewhere, for instance by having an image analysis program on a local computer analyzing the photograph or video, or having the photograph or video sent to a server for analyzing.

Turning back to the application on the smartphone <NUM>, it enables the smartphone to automatically connect to the computer system <NUM> when the identifier <NUM> is retrieved. The application also enables the smartphone <NUM> to be a user interface for the exchanges with the computer system <NUM> such as with the interactive managing routine of the entry point <NUM> and with the data base manager <NUM>.

Here, the computer system <NUM> is accessible through the Internet.

The entry point <NUM> is configured such that after having carried out the interactive managing routine which updates if needed the current value of the monitoring variable <NUM>, it hands over to the navigation manager <NUM> in certain circumstances.

The navigation manager <NUM> then redirects according to the circumstances to websites <NUM>. The application in the smartphone <NUM> hands over in turn to a web browser in the smartphone.

The data base manager <NUM> may also hand over to the navigation manager <NUM> in certain circumstances.

<FIG> shows the smartphone <NUM> taking a photograph or video of the pattern <NUM> of the spectacle lens <NUM> in the pair of spectacles <NUM>. The application in the smartphone <NUM> is able to take a picture or a video of also the pattern <NUM> of the other spectacle lens <NUM>, to retrieve the identifier included in this pattern and to interact in a same session with the computer system <NUM> for both identifiers, both for the spectacle lens <NUM> and the spectacle lens <NUM>.

In the variant shown on <FIG>, the pattern <NUM> is replaced by a RFID device <NUM>, that is the support <NUM> is the RFID device <NUM>.

Of course, it is desirable that the RFID device is selected as transparent so that the wearer of the pair of spectacles <NUM> is not disturbed by the RFID device <NUM>.

The reading and retrieving of the identifier <NUM> is similar as for the pattern <NUM>, except that a RF reader, such as one using a NFC protocol, is used instead of taking a photograph or video and analyzing it.

The application in the smartphone <NUM> is configured accordingly.

It should be noted that it is very convenient to use a consumer device such as the smartphone <NUM> for retrieving the identifier <NUM> and interacting with the computer system <NUM>.

It is of course possible to use different devices for retrieving the unique identifier <NUM> and for interacting with the computer system <NUM>. For instance, a photograph can be taken with a camera and sent to a personal computer having an image analysis program for retrieving the identifier <NUM>, and then to use a browser for accessing the computer system <NUM>.

Claim 1:
A method for monitoring a spectacle lens, the method including the steps of:
a) allocating to said spectacle lens (<NUM>, <NUM>) an identifier (<NUM>) that is unique to said spectacle lens (<NUM>, <NUM>);
b) incorporating into said spectacle lens (<NUM>, <NUM>) a transparent support (<NUM>) in which is coded said identifier (<NUM>) so that said support (<NUM>) is readable by an external reading tool (<NUM>) for retrieving said identifier (<NUM>);
c) providing data related to said spectacle lens to a predetermined database, before or after step b);
d) upon receiving a request issued from a requester, accessing the database and retrieving at least some of said data, the request including at least part of the identifier;
e) sending the retrieved data to the requester; and
f) optionally, either before step b) or after step e), receiving new data related to said spectacle lens and adding said data into the data base;
wherein the monitoring is performed at predetermined portions (<NUM>-<NUM>) of the lifetime of said spectacle lens (<NUM>, <NUM>), including at least one mounted-in-a-frame portion (<NUM>) in which the spectacle lens (<NUM>, <NUM>) is mounted in a frame (<NUM>); and
wherein a computer system (<NUM>) includes for said at least one mounted-in-a-frame portion (<NUM>) a data base section (<NUM>) that contains data representative of optical properties of said spectacle lens;
characterised in that said data base section (<NUM>) that contains data representative of optical properties of said spectacle lens (<NUM>) also contains data representative of optical properties of the other spectacle lens (<NUM>) in the pair of spectacles (<NUM>) in which is mounted said spectacle lens.