CN116194249A

CN116194249A - Centering device and method

Info

Publication number: CN116194249A
Application number: CN202180061020.8A
Authority: CN
Inventors: L·鲁赛尔; H·阿曼兰
Original assignee: Essilor International Compagnie Generale dOptique SA
Current assignee: EssilorLuxottica SA
Priority date: 2020-07-24
Filing date: 2021-05-05
Publication date: 2023-05-30
Also published as: WO2022017657A1; EP3943240A1; US20230249308A1; BR112023000250A2; CN214846114U

Abstract

The invention relates to a centering device comprising: -a chassis, -a bracket mounted on the chassis, the bracket being adapted to receive an ophthalmic lens, and-a centering device mounted on the chassis, the centering device comprising: a camera for acquiring an image of an ophthalmic lens when received on a support, and a screen for displaying the image acquired by the camera and a centering target superimposed on said image, said centering target comprising two coaxial and parallel contour lines (150, 151).

Description

Centering device and method

Technical Field

The present invention relates generally to the field of eyeglasses.

More specifically, the invention relates to a centering device comprising:

the base frame is provided with a base frame,

-a bracket mounted on the chassis, the bracket being adapted to receive an ophthalmic lens, and

-a centering device mounted on the chassis, the centering device comprising:

a camera for acquiring an image of an ophthalmic lens when received on a support, and

a screen for displaying the image acquired by the camera and a centering target (also called "reticle") superimposed on said image.

Background

The technical part of the optician work involving the installation of a pair of ophthalmic lenses into a spectacle frame selected by a customer can be divided into four main operations:

acquiring the shape of the rim contour of the spectacle frame selected by the customer,

centering each ophthalmic lens, including using centering marks provided thereon to determine the reference frame of the lens, and then positioning the pre-acquired rim profile appropriately under the reference frame of the lens, so that the lens is correctly positioned with respect to the corresponding eye of the customer as soon as it is trimmed to that profile and then mounted in its frame, and as much as possible performs its designed optical function,

blocking each lens, including attaching a blocking accessory to the lens, so that the lens can be easily removed from the centering station and then engaged in the edging station without losing the reference frame, and then

-edging each lens, including machining the lens into a pre-centered profile.

Here, attention is paid more specifically to the centering operation and the blocking operation.

These operations are typically performed by an optician using a centering-blocking device.

These apparatuses are generally configured in the same manner, with means for holding an ophthalmic lens, optical means for centering the ophthalmic lens, and blocking means for placing a blocking accessory on the lens.

Applicant sells an exemplary centering-blocking device under reference to Delta 2. In this device, the optical centering device comprises a camera and a screen on which the lens superposed on the centering line can be observed by the dispenser, allowing him to move the lens with respect to the line to correctly center the lens. The blocking device comprises itself an arm which is fixed and supports the blocking accessory. The lens support is movable along an axis parallel to the camera axis so that when centering the lens, the lens and its support can be pressed by the optician against the blocking accessory. The position of the blocking accessory on the lens then depends on the position of the lens relative to the reticle.

The reticle typically has a cross shape that is perfectly fit when the lens mark includes a point or cross to be centered on the reticle.

However, such markings do not always ensure a high degree of accuracy when the lens markings are different.

Indeed, the lens marks sometimes have a shape that makes the centering operation difficult to achieve. For example, the lens marks may be very many rounded micro-inscriptions distributed along concentric circles.

With such lens marks, it is difficult for the optician to center the reticle on the center of the concentric circles because the center is not marked.

Disclosure of Invention

Against this background, the present invention provides a centering device as disclosed in the introduction, having a reticle (referred to as "centering target") comprising two coaxial and parallel contour lines.

The shape of these contours depends on the shape of the lens marks. When the lens marks are formed of very many rounded micro-scores distributed along concentric circles, these contours are circular and designed to be placed on both sides of one of the concentric circles, thus enabling more accurate centering of the lens with respect to the reticle.

The principle of a reticle made up of at least two contours can be applied to the following lenses: the micro-inscription of the lens has a rounded shape, a square shape, or at least a closed shape (e.g., not a cross shape), or the micro-inscription of the lens is distributed along a contour having a rounded shape, a square shape, or at least a closed shape (e.g., not a cross shape).

Other preferred features of the invention are the following features:

at least one of said contour lines comprises a solid line,

each contour line has a circular shape,

each contour line has a square shape,

the size of at least one contour line is modifiable,

the distance between the contour lines is adjustable,

the size of both contours is modifiable,

the device comprises means for manually modifying the size of one of the contour lines displayed on the screen,

the device comprises means for determining the shape of a centering mark located on the lens, and means for automatically modifying the size of the contour line displayed on said screen according to the shape of the centering mark,

the device comprises blocking means mounted on the chassis, said blocking means being suitable for receiving a blocking accessory arranged to be attached to the ophthalmic lens.

The invention also applies to a method for centering an ophthalmic lens, comprising the steps of:

positioning the ophthalmic lens on a support,

capturing an image of an ophthalmic lens received on a holder by means of a camera,

-displaying an image acquired by a camera and a centering object superimposed on said image, said centering object comprising two coaxial and parallel contours, and

-manually modifying the position of the ophthalmic lens on the support.

In a preferred embodiment, the ophthalmic lens comprises a centering mark and the method comprises the following steps before or during the step of manually modifying the position of the ophthalmic lens: the distance between the two contours is adjusted according to the geometry of the centering marks.

Preferably, the two steps of manually modifying the position of the ophthalmic lens and adjusting the distance between the two contour lines are performed simultaneously by the optician. Indeed, the optician should first roughly position the lens so that the proportions of the contour lines can be adapted to the size of the centering marks. After the scaling of the contour lines, the optician can use them to more accurately position the lenses.

In a preferred embodiment, the centering marks comprise a pattern distributed along a contour centered on a point, the distance between the two contour lines being adjusted to be comprised between one and two times the width of the pattern, the width being measured radially with respect to the point.

In a preferred embodiment, the centering marks comprise a pattern distributed along concentric circles, and each contour line has a circular shape.

Drawings

The description which follows, with reference to the accompanying drawings, is given by way of non-limiting example only, and is made clear to the inventors of the invention itself.

In the drawings:

fig. 1 is a schematic view of a centering-blocking device according to the invention; and

fig. 2 is an example of a view displayed by a screen of the centering-blocking device shown in fig. 1.

Detailed Description

Fig. 1 shows an example of a centering-blocking device 1.

An optician uses such equipment to prepare an ophthalmic lens for edging to a given profile to mount the ophthalmic lens into a spectacle frame selected by a customer.

This device is generally used after the optician has obtained the shape of the contour C1 (see fig. 2) into which the lens must be trimmed. The apparatus is then used to perform the operations of centering and blocking the ophthalmic lens.

The purpose of the centering operation is to position the reference frame of the ophthalmic lens and to determine the position in which the above-mentioned contour must occupy in this reference frame, so that the lens is properly centered towards the corresponding eye of the customer (in order to fulfil as much as possible its designed optical function) as soon as it is trimmed to this contour and then mounted in the spectacle frame.

The purpose of the blocking operation is to place an accessory (called "blocking accessory") on the ophthalmic lens, making it easier to provide a stable coordinate system, allowing to position the reference frame of the lens after it has been transferred from the centering-blocking device 1 to the edging device.

An ophthalmic lens 100 to be edged is shown in fig. 2. The lens has two optical faces (i.e., a convex front face and a concave back face) and an edge that is initially circular in shape. The front and back surfaces of the ophthalmic lens 100 are shaped such that the lens has optical characteristics that allow correction of vision defects of a customer.

Here, the ophthalmic lens 100 includes a first optical correction for providing corrected vision to the wearer at a determined distance, and a second optical correction for altering the natural progression of myopia.

In our example, the first optical correction comprises a sphere power for providing the wearer with the correct distance vision (for looking at objects located more than 6 meters). The first optical correction may also include a cylinder power and/or a prism power.

The optical center of a lens is defined as the point at which the light rays of the lens pass through the lens without deviating.

In the first embodiment, it can be assumed that the centering point P1 of the ophthalmic lens 100 (i.e. the point at which the blocking accessory must be released) is formed by this optical center.

In a second embodiment, the centering point P1 is formed by the geometric center of a virtual rectangular box (called "box center") circumscribing the contour C1 along which the lens is to be trimmed.

In both embodiments, the centering and blocking device 1 should inform the trimming device at which point the blocking accessory is located.

The second optical correction provides additional optical characteristics. Such corrections are specifically designed to limit or prevent the progression of myopia.

In our example, ophthalmic lens 100 comprises a micromirror for this purpose. Such ophthalmic lenses are described in document WO 2019166654.

The ophthalmic lens 100 is provided with centering marks 110 that allow positioning of its reference frame.

These markings may take the form of temporary markings printed with ink and/or permanent markings (the microlitres mentioned) engraved on the lens.

Temporary marks generally allow the optical reference frame of the lens to be properly positioned prior to installation in the spectacle frame, while permanent marks allow the nature and characteristics of the ophthalmic lens to be identified and the exact position of the lens to be identified or reconstructed after removal of the temporary marks.

Here, the ophthalmic lens 100 has only permanent marks for determining the centering point P1 of the lens.

As shown in fig. 2, these microlithographic marks 110 are each rounded, they are very numerous, and they are distributed along concentric circles around the centering point P1 of the ophthalmic lens 100.

The lens includes more than three circles. Each circle contains more than ten marks 110.

The marks of the individual circles all have the same diameter D2. Here, all the marks have the same diameter D2. The diameter is less than 1mm.

In the disclosed embodiment, these centering marks 110 are formed by the contours of a micromirror engraved in one of the optical surfaces of the lens to achieve the second optical correction.

Here and preferably, the ophthalmic lens 100 is intended to be manually centered and blocked.

As shown in fig. 1, for this purpose the centering-blocking device 1 comprises at least:

the chassis (10) is provided with a base,

a bracket 20 mounted on the chassis 10 and adapted to receive an ophthalmic lens 100 (that is to say for supporting or blocking an ophthalmic lens),

a blocking device 30 mounted on the chassis 10 and adapted to receive the blocking accessory 200, and

a centering device 40 mounted on the chassis 10, comprising an aiming objective through which the optical reference system of the ophthalmic lens 100 can be observed.

The centering-blocking device may have several shapes. For example, the bracket may be fixedly mounted on the chassis and the blocking means may comprise a movable arm that is manually manipulable so that an optician can push the arm to place the blocking accessory on the lens.

In the illustrated embodiment, however, the blocking device 30 is fixedly mounted to the chassis 10, and the bracket 20 is movably mounted to the chassis 10.

The illustrated centering-blocking device 1 can now be briefly described.

As shown in fig. 1, in the depicted embodiment, the chassis 10 includes a dome 11. The dome 11 has a side wall whose top surface is provided with a large circular aperture centred on a main axis A1, here vertical. The dome also includes a bottom portion positioned in a horizontal plane and closing the back of the side wall. Finally, the dome includes a false bottom (bottom) 14 at a mid-height.

The false bottom 14 is visible through the large circular aperture 12. The false bottom has a circular hole centered on the main axis A1.

The blocking device 30 (designed to hold the blocking accessory 200) comprises a vertical shaft centered on the main axis A1. The vertical shaft has a lower end secured to the chassis and a free upper end for receiving the blocking accessory 200.

The bracket 20 is a transparent and vertical tube mounted on the chassis 10 so as to be able to slide along the main axis A1.

The upper end 22 of the bracket 20 is rounded and extends in a horizontal plane such that it is adapted to support the ophthalmic lens 100.

More precisely, the carriage 20 is mounted so that it can move between:

a centering position in which the ophthalmic lens 100 resting on the upper end 22 of the support 20 is at a distance from the blocking accessory 200, and

a blocking position in which the ophthalmic lens 100 rests on the blocking accessory 200.

Inside the dome 11 there is provided an elastic element suitable for automatically returning the support 20 to the centring position.

As a variant, the bracket may comprise three protruding pins forming a tripod for receiving the ophthalmic lens.

Advantageously, the centering device 40 is intended to observe the ophthalmic lens 100 along a viewing axis A2 parallel to (coincident herein with) the main axis A1.

As shown in fig. 1, these centering devices 40 here comprise means 50 for illuminating the ophthalmic lens 100 and means 60 for observing the ophthalmic lens 100 illuminated by the illumination means 50.

The illumination means 50 are distributed around the support 20 so as to produce grazing incidence on the optical surface of the lens placed on the support 20, here the convex front surface engraved with the centering marks 110.

In this case, the lighting devices 50 include a plurality of light emitting diodes regularly distributed around the holder 20.

The viewing device 60 comprises a mirror 63 inclined at 45 ° with respect to the main axis A1 and allowing redirecting the image of the ophthalmic lens 100 towards the objective 61 of the digital camera 62. The mirror 63 makes the centering and blocking device 1 more compact.

The digital camera 62 is then designed to take an image of the ophthalmic lens 100 and transmit the image to the viewing screen 70 oriented toward the face of the optician. The viewing screen 70 may be of any kind (e.g., LCD, TFT … …). The viewing screen is preferably mounted on the chassis 10 but may be remote from the chassis.

Thus, the optician can view the image of the ophthalmic lens 100 on this viewing screen 70 in real time, with the centering marks 110 provided on the lens clearly displayed.

The centering-blocking apparatus further includes a processing unit programmed to assist the optician in centering the ophthalmic lens 100.

For this purpose, the processing unit includes a Central Processing Unit (CPU), a memory, and input/output means.

The processing unit stores information used in the following process due to its memory. The memory stores, inter alia, a computer application constituted by a computer program comprising instructions, the execution of which allows the processing unit to implement the method described below.

The processing unit is connected to a viewing screen 70 to display a reticle superimposed with the image acquired by the camera 62.

The reticle is defined as a centering target or a fixed coordinate system indicating the position of the blocking accessory 200.

According to the invention, the reticle comprises two coaxial and

parallel contours

150, 151.

Each contour line is preferably a line (curve or a series of line segments) extending along the closed contour.

The shortest distance between these two

contours

150, 151 is parallel in the sense that any point along the entire closed contour is constant.

In effect, the outer contour 151 is an image of the inner contour 150 after similar expansion.

Because in the embodiment shown in fig. 2 the centering marks 110 comprise a pattern distributed along concentric circles, each

contour line

150, 151 here has a circular shape.

In a variant where the centering marks would include a pattern distributed along concentric squares, each

contour line

150, 151 would have a square shape.

These

contours

150, 151 are shown in solid lines on the viewing screen 70, but they may be shown in dashed or dotted lines.

These contours extend along the closed contour but may also be open over a part of its contour.

It is envisaged that the size of the contour cannot be changed. In a preferred embodiment, however, the size of at least one of the

contours

150, 151 is modifiable. The size of both contours is modifiable here.

This is preferred for the following reasons.

The size of the centering marks 110 displayed on the viewing screen 70 may vary due to the proportional modification caused by the lens power; thus, the distance between the contours may vary depending on the sphere power of the lens.

Furthermore, different brands of lenses may show centering marks with different sizes, which is why it is advantageous to make the size of the contour lines scalable.

Here, the radius R1 of the inner contour 150 is adjustable and the distance D1 between the two

contours

150, 151 is also modifiable.

Because of this, the two

contour lines

150, 151 may be sized to:

a single circle of centering marks 110 extending between the two, and

both contours are tangential to all centering marks 110 of the circle.

For this purpose, the distance D1 between the two

contour lines

150, 151 must be adjusted to be comprised between one and two times the diameter of the engraved micromirror.

In this position, the optician must well center the lens with respect to the blocking accessory 200.

In a first embodiment, the device 1 comprises an HMI (human-machine interface) enabling the optician to manually modify the size of the

contour lines

150, 151 displayed on the viewing screen 70.

If the screen is a touch screen, the HMI can be formed from the screen. In this embodiment, two buttons are shown associated with each contour, one button for increasing the size of the associated contour and the second button for decreasing its size.

In a second embodiment, the processing means is programmed to:

processing the acquired image of the lens to identify the characteristics of the centering mark 110, and

based on these features, the size and/or shape of the

contour lines

150, 151 displayed on the screen 70 is automatically modified.

More specifically, the processing means are programmed to determine in a first step the shape and position of each centering mark 110.

The processing means then determine whether a portion of the centering marks is distributed along the closed contour.

If this is not the case, a cross-shaped line is displayed on the screen. The exact shape of the reticle depends on the shape of the centering marks. In other words, the shape of the reticle depends on the lens type:

-a single-focus point of view,

the gradient of the material,

multifocal (an example of a bifocal lens is a monofocal lens fitted with a near vision lens affixed to the front face of the monofocal lens),

an example of an advanced lens is a bifocal lens, wherein near vision correction is performed by the bottom part of the lens, and far vision is performed by the upper part of the lens, said parts being separated by lines,

an example of an interviewed (interview) lens is a progressive lens with no distance vision correction, but only near vision correction and in-vision correction.

If this is the case, the processing means determine the shape of the detected closed contour (here, the shape is circular). The processing means then determine the average diameter of one of the detected circles along which the marks are distributed, and the diameter of these marks. Finally, the processing means display on the viewing screen two

contour lines

150, 151 adapted to the shape of the centering marks.

In other words, in this second embodiment, the processing means are programmed to propose a reticle shape suitable for the current lens family and selected among six different shapes.

To center the ophthalmic lens 100 and then block it, the optician uses the centering-blocking apparatus 1 in the following manner.

In a first step, the optician loads the blocking accessory 200 on a vertical shaft.

In a second step, the optician places the ophthalmic lens 100 on the upper end 22 of the support 20 in such a way that the convex front face of the lens rests on the support 20.

At this step, the camera 60 acquires images of the lenses, and these images are displayed on the viewing screen 70. These images are displayed together with two

contour lines

150, 151.

In a second embodiment, the size and shape of the two

contour lines

150, 151 are automatically modified to fit the shape of the centering mark 110.

In a third step, the optician manually moves the ophthalmic lens laterally, i.e. by sliding the ophthalmic lens on the support 20, until the ophthalmic lens 100 is placed on the axis of the blocking accessory 200. To this end, the optician views the images of the ophthalmic lens 100 on the viewing screen 70, these images being displayed superimposed with the

contour lines

150, 151. The optician then tries to place two

contours

150, 151 on each side of a single circle of centering marks 110 at this step.

In this step, in the first embodiment, the dispenser can manually modify the sizes of the two contour lines to achieve this.

Once this position is reached, the optician presses the ophthalmic lens 100 downward while taking care not to move the ophthalmic lens laterally to lower the carriage 20. This operation allows the lens to rest against the double-sided self-adhesive provided on the blocking accessory 200. In this way, the blocking accessory is automatically bonded to the lens in the desired position (precision better than half a millimeter).

The invention is in no way limited to the embodiments described and shown.

In particular, the blocking operation can be automated by equipping the support with a pneumatic or mechanical operating mechanism, and by equipping the centring-blocking device with electronic means for controlling the operating mechanism.

The invention is also applicable to automatic blocking systems (with a motorized arm that can place the blocking accessory on a specific point of the lens, and with centering means that assist the optician in manually positioning the lens with the aid of the camera taking this blocking point into account). According to another variant of the invention, the support can take a form different from that shown in the figures. Thus, the stand may take the form of a tripod mounted so as to be able to slide on the undercarriage in a plane orthogonal to the main axis A1.

According to another variant of the invention, the centering-blocking device can be operated automatically to center and block the lens (without the aid of an optician). With such an apparatus, the use of two contour lines enables a more accurate centering of the lens by the processing means.

Claims

1. A centering device (1), comprising:

-a chassis (10),

-a bracket (20) mounted on the chassis (10), the bracket being adapted to receive an ophthalmic lens (100), and

-a centering device (40) mounted on the chassis (10), the centering device comprising:

-a camera (60) for acquiring an image of the ophthalmic lens (100) when received on the holder (20), and

a screen (70) for displaying the image acquired by the camera (60) and a centering target superimposed on said image,

characterized in that the centering target comprises two coaxial and parallel contour lines (150, 151), and in that the size of at least one contour line (150, 151) is modifiable such that the distance between the contour lines (150, 151) is adjustable.

2. Centering device (1) according to claim 1, wherein at least one of the contour lines (150, 151) comprises a solid line.

3. Centering device (1) according to claim 1 or 2, wherein each contour line (150, 151) has a circular shape.

4. Centering device (1) according to claim 1 or 2, wherein each contour line (150, 151) has a square shape.

5. Centering device (1) according to any of claims 1 to 4, wherein the size of both contour lines (150, 151) is modifiable.

6. Centering device (1) according to claim 5, comprising means for manually modifying the size of one of the contour lines (150, 151) displayed on the screen (70).

7. Centering device (1) according to claim 5, comprising means for determining the shape of a centering mark (110) located on the lens (100), and means for automatically modifying the size of the contour lines (150, 151) displayed on the screen (70) according to the shape of the centering mark (110).

8. Centering device (1) according to any one of claims 1 to 7, comprising a blocking means (30) mounted on the chassis (10), suitable for receiving a blocking accessory (200) arranged to be attached to the ophthalmic lens (100).

9. A method for centering an ophthalmic lens, the method comprising the steps of:

positioning the ophthalmic lens (100) on a support (20),

-acquiring, by means of a camera (60), an image of the ophthalmic lens (100) received on the support (20), and

displaying an image acquired by the camera (60) and a centering target superimposed on the image,

manually modifying the position of the ophthalmic lens (100) on the support (20),

characterized in that the centering target comprises two coaxial and parallel contours (150, 151) and in that the size of at least one contour (150, 151) is modifiable before the step of manually modifying the position of the ophthalmic lens, such that the distance between the contours (150, 151) is adjustable.

10. The method according to claim 9, wherein the ophthalmic lens (100) comprises a centering mark (110), and wherein the method comprises the steps of: the distance between the two contours (150, 151) is adjusted according to the geometry of the centering mark (110).

11. The method according to claim 10, wherein the centering mark (110) comprises a pattern distributed along a contour centered on a point (P1), the distance between the two contour lines (150, 151) being adjusted to be comprised between one and two times the width of the pattern, said width being measured radially with respect to the point (P1).

12. The method according to claim 10 or 11, wherein the centering marks (110) comprise a pattern distributed along concentric circles, each contour (150, 151) having a circular shape.