CN214846114U

CN214846114U - Centering device

Info

Publication number: CN214846114U
Application number: CN202121380370.4U
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: 2021-06-21
Publication date: 2021-11-23
Anticipated expiration: 2031-06-21
Also published as: WO2022017657A1; EP3943240A1; CN116194249A; BR112023000250A2; US20230249308A1

Abstract

The utility model relates to a centering device, include: -a chassis, -a cradle mounted on the chassis, the cradle 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 it is received on the 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

Technical Field

The utility model relates to a glasses field generally.

More specifically, the present invention relates to a centering device

Background

The technical part of the dispenser work, which consists of fitting a pair of ophthalmic lenses into a spectacle frame selected by the customer, can be divided into four main operations:

-obtaining the shape of the rim profile of the spectacle frame selected by the customer,

centering each ophthalmic lens, comprising determining the reference frame of the lens using the centering marks provided thereon, and then positioning the pre-acquired rim contour appropriately under the reference frame of the lens, so that the lens, as soon as it is edged to this contour and then mounted in its frame, is correctly positioned with respect to the corresponding eye of the customer and as far as possible fulfils its designed optical function,

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

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

Here, the centering operation and the blocking operation are more specifically focused.

These operations are usually performed by the optician using centering-blocking devices.

These apparatuses are generally constructed in the same way, with means for holding the 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 Delta 2. In this device, the optical centering means comprise a camera and a screen on which the optician can view the lens superimposed on the centering reticle, allowing him to move the lens with respect to the reticle in order to correctly center the lens. The blocking device itself comprises 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 optician can press the lens and its support against the blocking accessory. The position of the blocking attachment on the lens then depends on the position of the lens relative to the reticle.

The reticle typically has a cross shape that is a perfect fit when the lens markings include a point or cross to be centered on the reticle.

However, such markings do not always guarantee a high degree of accuracy when the lenses are marked differently.

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

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

SUMMERY OF THE UTILITY MODEL

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

The shape of these contours depends on the shape of the lens markings. When the lens markings are formed by a very large number of rounded micro-engravings distributed along the concentric circles, these contour lines are circular and are designed to be placed on both sides of one of the concentric circles, which enables a more accurate centering of the lens with respect to the scale.

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

Other preferred features of the invention are the following:

-at least one of the 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 contour lines 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 the centering marks on the lens and means for automatically modifying the size of the contour lines displayed on said screen according to the shape of the centering marks,

the apparatus comprises blocking means mounted on the chassis, said blocking means being adapted to receive a blocking accessory arranged to be attached to the ophthalmic lens.

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

-positioning an ophthalmic lens on a carrier,

-acquiring an image of an ophthalmic lens received on a carrier by means of a camera,

-displaying an image acquired by a camera and a centering target superimposed on said image, said centering target comprising two coaxial and parallel contour lines, and

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

In a preferred embodiment, the ophthalmic lens comprises centering marks and the method comprises, before or during the step of manually modifying the position of the ophthalmic lens, the steps of: 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 scale of the contour lines can be adapted to the size of the centering marks. When the proportions of the contour lines are adjusted, the dispenser can use them to more accurately position the lens.

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

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

Drawings

The description which follows makes reference to the annexed drawings and which is given by way of non-limiting example, making clear the contents comprised by the invention and the manner of practicing the invention.

In the drawings:

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

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

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

Detailed Description

The optician uses this equipment to prepare an ophthalmic lens for edging to a given contour, to fit it into a spectacle frame chosen by the customer.

This apparatus is typically used after the dispenser has acquired the shape of the contour C1 (see fig. 2) that the lens must be edged to. The apparatus is then used to perform the centering and blocking operations on 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 this reference frame that the above-mentioned contour must occupy, so that the lens, as soon as it is trimmed to this contour and then mounted in the spectacle frame, is properly centered towards the corresponding eye of the customer (in order to achieve as much as possible the optical function for which it was designed).

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 locate the position of 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 properties that allow correction of defects in the vision of the customer.

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

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

The optical center of the lens is defined as the point where the light rays of the lens do not deviate when passing through the lens.

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

In the second embodiment, the centering point P1 is formed by the geometric center of an imaginary rectangular box (referred to as the "cartoning center") that circumscribes the contour C1 along which the lens is to be edged.

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

The second optical correction provides additional optical properties. This correction is designed specifically to limit or prevent the progression of myopia.

In our example, the ophthalmic lens 100 comprises a micro-lens for this purpose. Such an ophthalmic lens is described in document WO 2019166654.

The ophthalmic lens 100 is provided with centering marks 110 allowing to position its reference frame.

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

Temporary markings typically allow the optical reference frame of a lens to be properly positioned prior to installation of the lens in a spectacle frame, while permanent markings allow the properties and characteristics of an ophthalmic lens to be identified, and the exact position of the lens to be identified or reconstructed after removal of the temporary markings.

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

As shown in fig. 2, the micro-scale markings 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 comprises more than three circles. Each circle contains more than ten markers 110.

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

In the disclosed embodiment, the centering marks 110 are formed by contours of micro-lenses inscribed in one of the optical surfaces of the lens to effect the second optical correction.

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

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

-a base frame 10 for supporting the vehicle,

a cradle 20 mounted on the chassis 10 and suitable for receiving an ophthalmic lens 100 (that is to say for supporting or blocking it),

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

A centering device 40 mounted on the chassis 10 and 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 device may include a movable arm that is manually manipulable so that the optician may push the arm to place the blocking accessory on the lens.

In the illustrated embodiment, however, the blocking device 30 is fixedly mounted on the base frame 10, while the bracket 20 is movably mounted on the base frame 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, the top face of which is open with a large circular aperture centred on a main axis a1, here vertical. The dome further includes a bottom portion located in the horizontal plane and closing the back of the side wall. Finally, the dome includes a false bottom (false bottom)14 at mid-height.

The false bottom 14 can be seen through the large round aperture 12. The center of the false bottom has a circular hole centered on the major axis a 1.

The blocking device 30 (designed to hold the blocking accessory 200) includes a vertical shaft centered on a major axis a 1. The vertical shaft has a lower end fixed to the chassis and a free upper end for receiving a blocking accessory 200.

The carriage 20 is a transparent and vertical tube mounted on the chassis 10 so as to be able to slide along the main axis a 1.

The upper end 22 of the support 20 is circular and extends in a horizontal plane such that it is suitable for supporting an ophthalmic lens 100.

More precisely, the support 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 appendix 200.

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

As a variant, the support may comprise three projecting pins forming a tripod for housing the ophthalmic lens.

Advantageously, the centering device 40 is intended to observe the ophthalmic lens 100 along a viewing axis a2 parallel to (coinciding with) the main axis a 1.

As shown in fig. 1, these centering means 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 lighting means 50 are distributed around the support 20 so as to generate 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 means 50 comprise a plurality of light emitting diodes regularly distributed around the support 20.

The viewing device 60 comprises a mirror 63 inclined at 45 ° with respect to the main axis a1 and allowing to redirect the image of the ophthalmic lens 100 towards the objective 61 of the digital camera 62. This mirror 63 makes the centring-blocking device 1 more compact.

The digital camera 62 is then designed to take an image of the ophthalmic lens 100 and transmit it to the viewing screen 70 oriented towards the dispenser's face. 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 therefrom.

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

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

To this end, the processing unit includes a Central Processing Unit (CPU), a memory, and an input/output section.

Due to its memory, the processing unit stores information used in the processes described below. The memory stores, among other things, a computer application that is constituted by a computer program comprising instructions that, when executed, enable the processing unit to carry out 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 fixed coordinate system that indicates the position of the blocking accessory 200.

According to the utility model discloses, this marking includes two coaxial and

parallel outline lines

150, 151.

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

The shortest distance between these two

contour lines

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

In fact, the outer contour line 151 is an image of the inner contour line 150 after similar enlargement.

Since 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 variation where the centering marks would include a pattern distributed along concentric squares, each

contour

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 dotted or dashed lines.

These contour lines 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 lines cannot be changed. In a preferred embodiment, however, the size of at least one of the

contours

150, 151 is modifiable. Here, the size of both contour lines is modifiable.

This is preferable for the following reason.

The size of the centering mark 110 displayed on the viewing screen 70 may vary due to scale modification by lens power; thus, the distance between the contour lines 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 have the contour lines scalable in size.

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

contours

150, 151 is also modifiable.

Due to this, the size of the two

contour lines

150, 151 may be set to:

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

The two contour lines are tangent 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 micro-lens.

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

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

outline

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 displayed associated with each contour line, one for increasing the size of the associated contour line and a second for decreasing its size.

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

processing the acquired image of the lens to identify the features of the centering marks 110, an

Automatically modifying the size and/or shape of the

contour lines

150, 151 displayed on the screen 70 according to these characteristics.

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

The processing device then determines whether the partial centering marks are distributed along the closed contour.

If this is not the case, a cross-shaped reticle 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:

-of a single focal point,

-the light emitted by the light source is gradually changed,

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

an example of an advanced (advanced) lens is a bifocal lens, where near vision correction is performed by a bottom portion of the lens and far vision is performed by an upper portion of the lens, said portions being separated by lines),

an example of an interview (interview) lens is a progressive lens without distance vision correction, but with only near and intermediate vision correction.

If this is the case, the processing means determines the shape of the detected closed contour (here, the shape is circular). The processing means then determines 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 adapted to the current family of lenses and selected among six different shapes.

In order to centre and then block the ophthalmic lens 100, the optician uses the centring-blocking device 1 in the following manner.

In a first step, the optician loads the blocking accessory 200 on the 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 lens, 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 it on the carriage 20, until placing the ophthalmic lens 100 on the axis of the blocking accessory 200. For this purpose, the dispenser observes the images of the ophthalmic lens 100 on the viewing screen 70, which images are displayed superimposed on the

contour lines

150, 151. The dispenser then attempts to place two

contour lines

150, 151 on each side of the single circle of the centering mark 110 at this step.

At this step, in a first embodiment, the optician can manually modify the size of the two contour lines to achieve this.

Once this position is reached, the optician presses the ophthalmic lens 100 downwards, taking care not to move it laterally, to lower the carriage 20. This operation allows the lens to rest on the double-sided self-adhesive provided on the blocking accessory 200. In this way, the blocking accessory is automatically bonded to the lens at the desired location (with an accuracy 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 carriage with a pneumatic or mechanical handling mechanism, and by equipping the centering-blocking device with electronic means for controlling the handling mechanism.

The present invention is also applicable to automatic blocking systems (having a motorized arm that can place a blocking accessory at a particular point of the lens, and having a centering device that helps the optician manually position the lens with the help of the camera in view of the blocking point). According to another variant of the invention, the support can take a form different from that shown in the figures. The support may therefore take the form of a tripod mounted so as to be able to slide on the chassis in a plane orthogonal to the main axis a 1.

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 the optician). With such a device, the use of two contour lines enables the centering of the lens by the processing means to be more accurate.

Claims

1. A centering device (1) comprising:

-a chassis (10),

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

-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 said ophthalmic lens is received on the support (20), and

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

characterized in that the centering target comprises two coaxial and parallel contour lines (150, 151).

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

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

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

5. The centering device (1) according to any one of claims 1 to 4, wherein the size of at least one contour line (150, 151) is modifiable such that the distance between the contour lines (150, 151) is adjustable.

6. The centering device (1) according to any one of claims 1 to 4, wherein the size of both contour lines (150, 151) is modifiable.

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

8. Centering device (1) according to claim 6, 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).

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