KR20050103971A - Method for machining an ophthalmic lens and machining device for carrying out said method - Google Patents

Abstract

The invention relates to a machining method carried out with the aid of a digital grinder comprising a first axis and at least one grindstone (6) mounted thereon and a second axis on which a machined blank is arranged in order to produce a desired ophthalmic lens. The inventive method consists in a) mounting a template (2') corresponding to the desired lens on the second axis, b) bringing said template (2') into contact with a tool (6) arranged on the first axis, 3) recording the relative position of two axes with respect to each other, d) repeating the steps b) and c) in order to carry out a discrete or continuous reading of the entire template (2'), e) determining the shape of the template (2') by calculation, f) removing the template (2'), g) mounting the blank, h) machining said blank and I) in possibly machining a second blank.

Description

METHOD FOR MACHINING AN OPHTHALMIC LENS AND MACHINING DEVICE FOR CARRYING OUT SAID METHOD}

The present invention relates to a method of processing an ophthalmic lens.

The processing of the ophthalmic lens is generally carried out by grinding blanks. According to such a processing method, a predetermined lens shape can be provided to the semi-finished product so that the processed lens can be attached to the ring of the spectacle frame well.

In order to give a suitable shape to the spectacle frame corresponding to the lens, the following two techniques are mainly used.

According to the first technique, a template is used that takes the form of an eyeglass frame to be mounted with a lens. The model is mounted on a grinding machine to process semi-finished products. The grinding machine can duplicate the shape of the model. This replication process is mechanical. The machining trajectory is created by a model moving on a touch key having a radius substantially the same as the radius of the grinding wheel. According to such a replication method, the shape of the model can be sufficiently reproduced. On a machining device of this type, no inclined section for a controlled orbit is generally obtained. This cross section can only be obtained by a tool mounted on a floating axis, but it cannot fully control the trajectory of the tool.

As a second technique, there is a technique using a digital grinding machine. Such a grinding machine is coupled to a reading device that digitizes the annular shape of a predetermined spectacle frame for a given glass lens prior to processing the finished product. The recorded data is then transferred to the grinding machine. Grinding machines typically have three digital axes and can precisely control the trajectory during machining. Digital grinding machines are devices that are considerably more expensive than grinding machines using models, especially due to the reading device connected thereto. In addition, such a reading device is on the one hand a sensitive and brittle element, and on the other hand, a device that is difficult to maintain.

In order to manufacture eyeglasses in a so-called "new country", it is better to propose a processing device having a relatively low price for convenience and easy maintenance in case of failure. As can be seen from the description of the above methods, a machining apparatus using a model meets this economic requirement but above all exhibits the disadvantages described above. Moreover, it is not possible to precisely control the position of the cross section in the lens to finish the lens. This is a serious problem, especially when ophthalmic lenses are made of polycarbonate.

1 is a partial perspective view briefly showing an apparatus for processing an ophthalmic lens that can be used to practice the method according to the invention.

FIG. 2 is an elevation view schematically showing the main components of the apparatus shown in FIG. 1.

3 is a top view of the apparatus shown in FIG. 2.

Accordingly, it is an object of the present invention to provide a method for manufacturing a glass lens of an eyeglass or an ophthalmic lens, and to provide a method capable of controlling the processing level by a digital grinding machine while using only a tool that is reliable and easy to maintain.

Indeed, according to the present invention, an ophthalmic lens using a digital grinding machine comprising a first axis equipped with one or more rotary grinding wheels 6 and a second axis arranged with a semifinished product to be processed to produce a lens of a given ophthalmology A method of processing is provided.

According to the invention, the method,

(a) mounting a model on the second axis corresponding to the desired lens to be obtained;

(b) contacting the model with a tool mounted on the first axis;

(c) recording the position of the two axes relative to each other;

(d) repeating steps (b) and (c) to perform a continuous or discontinuous reading of the entire model;

(e) determining the shape of the model by calculation;

(f) removing the model;

(g) mounting the finished product to be processed;

(h) processing the semi-finished product; And

(i) optionally processing a second workpiece;

It includes.

According to the method of the present invention, it is possible to cause a tool arranged on the first axis of the grinding machine to "decipher" the model arranged at the position of the second axis. The tool is used as a contactor and allows the means used to operate the grinding machine to recognize the exact shape of the model used. Recognizing the shape in this way, the operating means of the grinding machine can act to produce an ophthalmic lens that duplicates the same contour as the model on various tools of the grinding machine.

In the machining method according to the present invention, an example of a tool used for contacting a model is a rotary grinding wheel used for processing a semi-finished product. In this case, the grinding grinding wheel is preferably free of rotation about its axis during steps (b) and (c). However, the tool used may be a special tool used as a contactor.

According to one embodiment of the present invention, after each recording is carried out in step (d), the tool and the model are separated from each other, the model is rotated by a predetermined increment, and then the model and the tool are brought into contact again to follow Take a record.

The machining method according to the invention can be used, for example, with a grinding machine of the type comprising the following components:

A first axis equipped with at least one grinding wheel;

A second axis parallel to said first axis, said second shaft being centrally arranged to hold the workpiece to be machined between them in an extension line with each other;

Means for driving at least one of the two shafts;

A rotor rotatably mounted about a third axis parallel to said first and second axes, said rotor having shafts suitable for holding and moving a workpiece to be machined;

A link mounted between one end of a third shaft with the rotating body and a movable nut mounted on a fourth shaft perpendicular to the third shaft;

Means for driving said movable nut; And

A support and a ring mounted on the link on the one hand and on the rotor on the other hand in order to limit the movement of the workpiece supported by the rotor towards the rotary grinding wheel. counter-support system.

Grinding machines of this type are well known to those skilled in the art. An advantage of the method according to the invention is that it is possible to use a grinding machine of the prior art. However, a grinder of the type described above may optionally be used in combination with a reading system that digitizes the annular frame of the spectacle frame. When used in the method of the present invention, the reading system is useless. Therefore, an ophthalmic lens processing apparatus can be obtained which provides all the advantages of the digital processing apparatus at low cost.

When using a grinding machine of this type, during the steps (b) to (d) corresponding to the reading of the model, the model is present on a tool arranged on the first axis and the model is Driven by rotation about an axis, the relative position of the two axes is measured by detecting the movement of the rotor about that axis. At this time, the movement of the rotating body can be detected by using, for example, an angular motion catcher disposed on the rotating shaft of the rotating body.

The invention also relates to an apparatus for processing an ophthalmic lens comprising the following components:

A first axis equipped with at least one grinding wheel;

A second axis parallel to said first axis, said second shaft being centrally arranged to hold the workpiece to be machined between them in an extension line with each other;

Means for driving at least one of the two shafts;

A rotor rotatably mounted about a third axis parallel to said first and second axes, said rotor having shafts suitable for holding and moving a workpiece to be machined;

A link mounted between one end of a third shaft with the rotating body and a movable nut mounted on a fourth shaft perpendicular to the third shaft;

Means for driving said movable nut; And

A support and ring system mounted on the link on the one hand and on the rotor on the other hand to limit the movement of the semi-finished workpiece supported by the rotating body towards the rotary grinding wheel.

In an embodiment suitable for carrying out the method of the invention, the first axis of the device further comprises a contacting tool for contacting the model mounted between the two shafts of the second axis, wherein the drive means of the movable nut comprises: And an encoder capable of accurately recognizing the position of the nut on the fourth axis. In such a novel apparatus, the contact tool is in the form of a smooth disk, for example in the form of a rotary grinding wheel mounted on the first axis.

In addition, the present invention relates to an apparatus for ophthalmic lens processing of the type described above, comprising a pressure catcher between the link and the support system of the rotating body and the ring system.

  Hereinafter, on the basis of the accompanying drawings will be described in more detail the configuration and advantages of the present invention.

According to the invention, it is possible to use known types of digital grinding machines such as model decoders and grinding machines. First, a grinding machine that can be used to practice the method of the present invention will be described, and then the method of the present invention using the apparatus described above will be described in detail.

FIG. 1 shows a partially simplified view of an apparatus 1 for processing an ophthalmic lens 2. The grinding machine is for defining the contour of the lens 2 to match the contour of the ring of the spectacle frame (not shown) after grinding.

The grinding machine 1 comprises two support shafts 4 and 4 'facing each other, and the lens 2 is held in a clip manner between the two shafts. The support shafts 4, 4 ′ are cooperatively driven by the rotation of a first motor (not shown) around a common first axis A1. However, only one of the two shafts may be driven while the other may be mounted with a rotating material.

The rotating shafts 4, 4 ′ are mounted on a movable support 5, which is named as a rotating body. The rotating body 5 is rotatably mounted on a frame (not shown) of the grinding machine 1 around a second axis A2 parallel to the first axis A1.

In addition, the grinding machine 1 is disposed on the right side of the support shafts 4, 4 ′ and driven to rotate about a third axis A3 parallel to the first and second axes A1, A2. Rotary grinding wheel 6. By moving the rotary body 5 in such a manner as to move the support shafts 4 and 4 'away from or near the rotary grinding wheel 6, the contour of the lens 2 is generally non-circular. Can be made in form

The first motor is mounted, for example, on the rotating body 5, wherein the rotational movement of the rotating body is supported by the shaft motor of the second shaft A2 via the transmission belt via the support shafts 4 and 4 '. Is passed on. However, this transfer process can also be accomplished by a gear mechanism.

In practice, a number of rotary grinding wheels may be provided side by side on the third axis A3 for one-time finishing and one semi-finished product of the lens 2 to be machined. These rotary grinding wheels are supported by carriers (not shown) that are movable in translational motion along axis A3. The possibility of movement due to this translational movement is shown by a double arrow Z in FIG. 1.

1 to 3, only one rotary grinding wheel 6 is shown. At this time, one finishing rotary grinding wheel 6 has a thin groove 11 for processing a four-sided surface on the lens 2.

The grinding machine is a digitally controlled grinding machine. According to the embodiment shown in FIG. 1, the grinder is, on the one hand, through a first end 13 in a gap around the second axis A2 of the rotary body 5, and on the other hand the mill. And a link 12 artically mounted on the nut 15 via a second end 14 about a fourth axis A4 parallel to the first to third axes A1, A2, A3. At this time, the nut 15 is movably mounted by translating along a fifth axis A5, commonly referred to as a restoring axis and perpendicular to the first axis A1. The possibility of movement by the translational movement of the nut 15 is shown by a double arrow X in FIG. 1.

The nut 15 is perforated and secured in a threaded manner with the threaded rod 16 extending along the fifth axis A5, around which the nut 15 is formed. It is rotationally driven by two motors M2.

Between the rotary body 5 and the link 12, a contact capturer 17, for example an electromagnetic, optical or more simply an electrical contact capturer, is interposed.

The rotating body 5 is provided such that the lens 2 to be processed, which is inserted between the two shafts 4 and 4 ', is present at the base of the rotary grinding wheel 6 with the support shafts 4 and 4'. When contacted with the rotary grinding wheel 6 by rotating toward the working position (FIG. 1), the lens 2, which is rotated by the shafts 4 and 4 ′, has the rotary body 5 connected to the link 12. It becomes the object of material removal by the rotary grinding wheel 6 until () is pressed, and the time point at which a rotating body presses is detected by the catcher 17.

In the working position, the lens 2 is under the weight of the rotor 5 with the pulling force of the spring (not shown) tending to attract the rotor 5 towards the rotary grinding wheel 6. It comes into contact with the rotary grinding wheel 6.

In practice, the programmed computing unit coordinates this operation and in particular controls the second motor M2. The angular position of the lens 2 around the first axis A1 and the angular position of the link 12 around the second axis A2 are recognized every moment. The angular position of the link 12 corresponds to the final position of the rotary body 5 at every moment, where the final position is the difference in angular difference between them when the link 12 and the rotary body 5 are in contact. It is corrected.

The angular position of such a link 12 corresponds to the linear position of the nut 15 along the longitudinal direction of the rod 16 called the final machining command.

Further, the machining of the lens 2, which is described as being achieved when the rotor 5 presses the link 12, is detected through the complete rotation of the lens 2 around the first axis A1. In this case, the contour of the lens 2 takes the form of a ring of spectacle frames to be obtained later, as mentioned above.

Grinding machines of this type to which the method of the invention can be applied are not only well known to those skilled in the art, but are also commercially available and subject to a number of patent applications. In particular, reference may be made to a patent publication filed in French patent application FR-95.06236 and registered as FR-A-2 734 505.

In the present invention, it is proposed to use the grinding machine (or other type of digital grinding machine) mentioned above as a model decoder.

First, the model 2 'is interposed between the two shafts 4 and 4' (Fig. 2). The model 2 'is a model of the same type as used in a grinding machine using a model of the prior art, which is incorporated herein by reference. The model 2 'has a contour in the form corresponding to the contour of the spectacle frame. In a conventional manner, the model 2 'has two parallel surfaces and does not have convex and / or concave surfaces like the ophthalmic lens 2 to be processed.

Once the model 2 'is in place, the rotary body 5 is lowered until the model 2' contacts the rotary grinding wheel 6. The contact position is then indicated by the link 12. Indeed, the motor M2 is mounted on the nut 16 on the threaded rod 16 until the contact 17 is located on the link 12 and meets the ring system 17 'provided on the rotor 5. Operate to move 15). At this time, the position corresponding to the contact point is indicated by the encoder 18 connected to the motor M2. The position is stored in a calculation unit connected to the grinding machine.

Then, the nut 15 is moved downwards (where the up / down direction is shown in the state shown in the drawing. This direction also corresponds to the direction of the grinding machine as shown in the drawing, but may take other directions. ), The rotary body 5 is raised upward so that the model 2 'is no longer in contact with the rotary grinding wheel 6. Subsequently, the model 2 'is driven to rotate about the axis A1 by the support shafts 4 and 4' by a predetermined angle value, for example, 0.5 °. Subsequently, the model 2 'is newly contacted with the rotary grinding wheel 6, and the position is recorded by moving the link 12 via the nut 15 driven by the motor M2.

For the model 2 ', various positions corresponding to the nut 15 on the threaded rod 16 are successively recorded by the encoder 18. This position measurement is resumed to measure the distance between the axis A1 and the axis A3 supporting the rotary grinding wheel 6 for each position of the model 2 'around the axis A1.

In the case where the model 2 'is perfectly decoded, i.e., a 360 ° rotation (adding up the increments) around the axis A1, the calculation unit of the grinding machine is provided with the value provided by the encoder 18. Can be used to calculate the contour of the model 2 '. Then, the model is removed from the axis A1 and the semi-finished product of the ophthalmic lens 2 is placed in place.

The process of processing the semi-finished product to obtain the ophthalmic lens 2 is carried out in a conventional manner such as performing processing using a digital grinding machine. The data used for the grinding operation is the data calculated as a result of reading the model 2 '. As is commonly practiced, the front and rear surfaces of the finished product are promoted on the axis A1. The semi-finished product is then processed and optionally cut obliquely along the trajectory calculated from the data recorded in the readout step of the model 2 '. The first machining operation, for example, makes the right lens of the corresponding spectacle frame. In the same way, using the recorded and stored data, processing of the left lens and optionally inclined plane cutting is performed.

As mentioned above, according to the method according to the present invention, it is possible to use a digital grinding machine such as a model decoder. Therefore, there is no need to connect a special decoder to the grinder which digitizes the frame shape of the spectacle frame. In general, since the cost of the decoder connected to the digital grinding machine is reduced, the method of the present invention achieves all the beneficial effects of the digital grinding machine at a much lower cost. Indeed, a computational unit that recognizes the shape to be provided for the finished product to be processed can perform all processing operations to obtain a perfectly finished spectacle lens (such as a cross section).

As mentioned above, the method according to the present invention can be used without modification of the conventional digital grinding machine. In addition, such a grinding machine can be adapted to suit the present invention. For example, instead of using the rotary grinding wheel 6 to machine the finished product to decode the model, a set of rotary grinding wheels 6 with a disk 19 as shown in dashed lines in FIG. The method of use can also be considered. The disk is, for example, a smooth disk having the same three-dimensional shape as the rotary grinding wheel 6. There may also be one or more capturers (not shown) for detecting contact with the model 2 'on the disc. Such a catcher is advantageously a pressure catcher. This type of pressure trap may be arranged between the link 12 and the rotating body 5 for replacement of the trap 17 or instead of the trap 17. If there are two catchers, one of the two catchers (eg a pressure catcher) can be used for the steps involved in the detoxification of the model 2 'and the other (for example the catcher 17). )) Can be used in the processing of semi-finished products.

In special cases, frames without models may be provided. Frames known as the trademark "NYLORS" or frames used with perforated lenses may be exemplified, in the case of perforated lenses, each lens on one hand to accommodate a pair of spectacles and on the other "nose". Make a hole to connect with the other lens of the glasses. In this case, a display lens provided with the frame as described above may be used instead of the model. Therefore, the term "model" in the present specification is meant to include such a display lens.

The present invention is not limited only to the method as exemplified above, and the above-described embodiments are merely exemplary, and various modifications may be made. In addition, modifications of the invention carried out by those skilled in the art are also included in the protection scope of the invention as defined by the appended claims.

For example, the present invention may be practiced using other types of grinding machines than those belonging to the types as described above and those shown in the figures.

In addition, decoding of the model can also be performed in different ways. Instead of moving the links and the rotor in increments of the model to decode the relative positions of the axes of the rotary grinding wheel and the axes of the model, for example, the shape of the model may be decoded in the following manner. The model is mounted on its axis, optionally in a position provided to accommodate the blank to be machined. The set of rotary grinding wheels is moved so that the tool for decoding the shape of the model faces the model. The rotor is then moved so that the model is in contact with the tool used for decryption. Next, the model is driven to rotate about its axis. The shaft is supported by the rotating body. The axes of the rotating body and the axes of the rotary grinding wheel set are axes fixed on the frame of the grinding machine. While rotating the model, the rotor will oscillate around its axis as the radius of the model changes. For example, by recording such a vibration using a capturer disposed on the axis of the rotating body, the shape of the model can be determined by calculation. During this decryption, the movable nut is placed on the threaded rod in such a way that the catcher disposed on the link does not contact the connected ring system so that it does not cause movement of the rotor. In this case, the shape decoding of the model can be performed in a discontinuous or continuous manner.

Claims (10)

A digital grinding machine (1) comprising a first axis (A3) equipped with one or more rotary grinding wheels (6) and a second axis (A1) on which the workpiece is to be processed so as to produce a predetermined ophthalmic lens (2). In the method of processing the ophthalmic lens 2 using (a) mounting on the second axis A1 a model 2 'corresponding to the desired lens to be obtained; (b) contacting the model 2 'with a tool (6; 19) mounted on the first axis (A3); (c) recording the positions of the two axes A1 and A3 relative to each other; (d) repeating steps (b) and (c) to perform a continuous or discontinuous reading of the entirety of the model (2 '); (e) determining the shape of the model 2 'by calculation; (f) removing the model 2 '; (g) mounting the finished product to be processed; (h) processing the semi-finished product; And (i) optionally processing a second workpiece; Method of processing an ophthalmic lens (2) characterized in that it comprises a. The method of claim 1, A method for processing an ophthalmic lens (2), characterized in that the tool used for contacting the master (2 ') is a rotary grinding wheel (6) used for processing a semi-finished product. The method of claim 2, A method for processing an ophthalmic lens (2), characterized in that the rotary grinding wheel (6) is freely rotatable about the axis (A3) during the steps (b) and (c). The method of claim 1, A method for processing an ophthalmic lens (2), characterized in that the tool used for contacting the model (2 ') is a special tool (19) used as a contact key. The method according to any one of claims 1 to 4, In step (d), after each recording is performed, the tool 6; 19 and the model 2 'are separated from each other, the model is rotated by a predetermined increment, and then the model 2' and the tool And (6; 19) to contact again to effect subsequent recording. The method according to any one of claims 1 to 5, The grinding machine 1 used is, A first axis A3 equipped with one or more rotary grinding wheels 6; A second axis A1 parallel to the first axis A3, with the two shafts 4, 4 'centrally arranged to hold the workpiece to be processed between them on an extension line with each other; Axis A1; Means for driving at least one of the two shafts (4, 4 '); A rotary body (5) rotatably mounted about a third axis (A2) parallel to said first and second axes (A3, A1), said shaft being adapted to hold and move the workpiece to be processed ( A rotating body 5 having 4, 4 '); Mounted between one end of a third axis A2 with the rotating body 5 and a movable nut 15 mounted on a fourth axis A5 perpendicular to the third axis A2. Link 12; Means (M2) for driving said movable nut (15); And -On the one hand on the link 12 and on the other hand the rotor 5 in order to limit the movement of the workpieces supported by the rotor 5 towards the rotary grinding wheel 6 Support and ring systems 17, 17 ′ mounted on the backplane; Method for processing the ophthalmic lens (2) characterized in that the grinding machine of the type comprising a. The method of claim 6, During the steps (b) to (d) corresponding to the reading of the model 2 ', the model 2' is present on a tool 6; 19 arranged on the first axis A3, The model 2 'is driven by rotation about its axis A1 and the relative positions of the two axes A1, A3 c move around its axis A2 of the rotating body 5. And measuring by detecting the ophthalmic lens (2). A first axis A3 equipped with one or more rotary grinding wheels 6; A second axis A1, parallel to said first axis, with a second axis (4, 4 ') centrally arranged to hold the workpiece to be processed between them on an extension line with each other ( A1); Means for driving at least one of the two shafts (4, 4 '); A rotary body 5 rotatably mounted about a third axis A2 parallel to the first and second axes, the shafts 4 and 4 'being suitable for holding and moving the workpiece to be processed. Rotor 5 having a; Mounted between one end of a third axis A2 with the rotating body 5 and a movable nut 15 mounted on a fourth axis A5 perpendicular to the third axis A2. Link 12; Means (M2) for driving said movable nut (15); And -On the one hand on the link 12 and on the other hand the rotor 5 in order to limit the movement of the workpieces supported by the rotor 5 towards the rotary grinding wheel 6 Support and ring systems 17, 17 ′ mounted on the backplane; In the device (1) for processing the ophthalmic lens (2) comprising: The first axis A3 further comprises a contact tool 19 for contacting the model 2 'mounted between the two shafts 4, 4' of the second axis A1, The drive means M2 of the movable nut 15 comprises an encoder 18 which is capable of accurately recognizing the position of the nut 15 on the fourth axis A5. Device for processing. The method of claim 8, The contact tool (19) is an apparatus for processing an ophthalmic lens (2), characterized in that it has a smooth disk shape taking the form of a rotary grinding wheel mounted on the first axis (A3). A first axis A3 equipped with one or more rotary grinding wheels 6; A second axis A1, parallel to said first axis, with a second axis (4, 4 ') centrally arranged to hold the workpiece to be processed between them on an extension line with each other ( A1); Means for driving at least one of the two shafts (4, 4 '); A rotary body 5 rotatably mounted about a third axis A2 parallel to the first and second axes, the shafts 4 and 4 'being suitable for holding and moving the workpiece to be processed. Rotor 5 having a; Mounted between one end of a third axis A2 with the rotating body 5 and a movable nut 15 mounted on a fourth axis A5 perpendicular to the third axis A2. Link 12; Means (M2) for driving said movable nut (15); And -On the one hand on the link 12 and on the other hand the rotor 5 in order to limit the movement of the workpieces supported by the rotor 5 towards the rotary grinding wheel 6 And ring systems (17, 17 ') mounted on In the device (1) for processing the ophthalmic lens (2) comprising: Apparatus for processing ophthalmic lens (2) characterized in that a pressure trap (17) is provided between the link (12) and the support system (17) of the rotating body (5) and the ring system (17). .