Abstract:
To at least one of mark and drill holes in a workpiece spectacle lens, a position of bores of a lens template is scanned, in which the template includes one of a template spectacle lens, a pattern disk and a support disk. The scanning is performed by a scanning arrangement situated in one of a device for coquilles, a device to cut support disks for spectacle frames, and a spectacle lens edging machine. Data is acquired concerning the position of the bores in accordance with the scanning, and is then fed to a computer. The data includes at least one of rectangular and polar coordinates of the position of the bores. At least one of marking and drilling the holes in the workpiece spectacle lens is performed using a Computer-Numeric-Controlled device in accordance with the data concerning the position of the bores.

Description:
FIELD OF THE INVENTION 
     The invention relates to a method for marking or drilling holes in spectacle lenses, and to a device for carrying out the method. 
     BACKGROUND INFORMATION 
     The nose bridge and the bows of rimless spectacles are usually screwed onto the form-ground spectacle lenses. It is therefore necessary for the bores for fastening the nose bridge and the bows to be made in a positionally accurate fashion in the form-ground spectacle lenses. The position of these bores is determined by the shape of the spectacle lenses and of the nose bridge and the bows and fixed by the manufacturer of these parts. For the purpose of selecting such rimless spectacles, the elements, screwed onto a so-called support disk, are supplied and permit the rimless spectacles to be tried without the use of optical lenses. Frequently, a pattern disk for grinding the contour of the spectacle lenses is also supplied with the rimless spectacles, and this pattern disk is likewise provided by the manufacturer with the bores for fastening the spectacle frame elements. 
     The optician uses the pattern disk or support disk provided with the fastening bores to mark the bores on a spectacle lens, and drills the holes by means of a suitable drilling device. 
     If the spectacle lenses are to be exchanged while retaining the elements of the spectacle frame, because, for example, the visual acuity of the spectacle wearer has changed, or because one of the spectacle lenses has been broken, it is possible to use an existing spectacle lens, already provided with bores, for marking the bores. 
     SUMMARY OF THE INVENTION 
     It is obvious that this marking of the bores and the subsequent drilling of the holes are attended by a substantial manual outlay which requires great skill on the part of the optician and therefore gives rise to costs which can also rise by virtue of the fact that drilling the holes by means of conventional drilling devices frequently leads to breakage of the spectacle lens, which can then no longer be used. 
     It is the object of the invention to simplify and speed up the marking or drilling of holes in spectacle lenses, to increase the accuracy and to reduce the risk of lens breakage when drilling. 
     Starting from this formulation of the problem, a method is proposed for marking or drilling holes in spectacle lenses, in which, according to the invention, the position of bores in a spectacle lens or a pattern disk or a support disk is scanned with or without contact, the data acquired on the position of the bores are fed to a computer as rectangular or polar coordinates and used to control the marking or drilling by means of a CNC-controlled marking or drilling device. 
     The invention proceeds from the consideration that the outlay on acquiring the data on the position of the bores is small, since only one pair of values (x, y), (r, φ) is required for each bore, and these pairs of values can accurately and quickly effect control of the marking or the drilling by means of a CNC-controlled marking or drilling device. 
     The marking of the holes can be performed by means of an ink jet or a counterboring cutter. In this case, the actual drilling of the holes is carried out in a conventional drilling device. 
     The holes are preferably drilled by means of a CNC-controlled drilling device, it being necessary to adapt the drilling tool to the spectacle lens material. If, for example, silicate lenses are involved, it is preferred to use a diamond drilling tool, while drilling tools made from hard metal are suitable for drilling plastic lenses. 
     The scanning of the position of the bores can be carried out, for example, in a centering device for coquilles. Such centering devices serve the purpose of mounting a holding element in the form of a block or sucker on a coquille which can be detected in a viewing optics or on a screen, and on which an image of the form-ground spectacle lens is superimposed in accordance with the spectacle frame, in order to insert the coquille in a positionally accurate fashion into a spectacle lens holding shaft on a spectacle lens edging machine, after which form grinding is carried out in accordance with the prescribed spectacle lens shape. 
     The scanning of the position of the bores can also be carried out in a device for scanning the contour of a pattern disk. By means of such a device, the contour of a pattern disk is acquired in the form of a data record and used to control the form grinding by means of a CNC-controlled spectacle lens edging machine. Moreover, it is also possible for the position of the bores to be scanned in a device for cutting support disks for spectacle frames. Support disks are used, inter alia, for the purpose of marking the viewing points of the spectacle wearer during adaptation to the new spectacle frame. Such a device for cutting support disks is described in DE 40 03 001 C1 of the same applicant. 
     A further possibility for scanning the position of the bores consists in making use for this purpose of a spectacle lens edging machine in which the marking or drilling of the holes is also performed. It is advantageous in this case to make use of the same computer for acquiring the data and for controlling the marking or drilling, as well as for controlling the form grinding of the spectacle lens. 
     A video system with screen display of the contour of the spectacle lens or the pattern disk or the support disk and the bores can also be used for scanning the position of the bores if this video system is set up such that the acquisition of the data on the position of the bores is performed by means of automatic image evaluation. 
     In the case of a video system without automatic image evaluation, or if the spectacle lens, the pattern disk or the support disk are laid onto a digitizing tablet, the data on the position of the bores can be acquired by marking the bores, which are visible on the screen or the digitizing tablet, by means of a cursor which can be moved by a keyboard or a computer mouse, and are recorded by clicking on the respective bore. 
     The position of the holes in spectacle lenses can be input in a particularly simple way as a data record into a computer which is used for directly controlling the marking or drilling by means of a CNC-controlled marking or drilling device. This inputting of the data record can be accomplished in the form of rectangular or polar coordinates by means of a keyboard connected to the computer, or by reading in the data record, which is stored on a floppy disk, an EPROM or a magnetic strip, or is represented by means of a barcode. These stored data records can be supplied by the manufacturer of the spectacle frame, and can also comprise a data record for grinding the circumferential contour of the spectacle lens. It is likewise possible to acquire these data records by scanning a spectacle lens, a pattern disk or a support disk. 
     In order to solve the problem mentioned at the beginning, there is proposed a marking or drilling device for marking or drilling holes in spectacle lenses, having an input device for inputting the coordinates (X n , Y 1 ; X 2 , Y 2 ) or (r n , φ n ) of the holes into a computer and a positioning device, controlled by the computer in accordance with the input coordinates, for the marking or drilling device with reference to the spectacle lens. A laser drill may be used as the marking or drilling device. 
     If use is made of a drilling tool running at high speed, it is possible to use for this a drive designed as an air turbine, as a combined air-water turbine or as a high-frequency electric motor. 
     Particularly preferred is a marking or drilling device on a spectacle lens edging machine, having a computer for controlling the form grinding of spectacle lenses, at least one grinding wheel in a grinding chamber, a spectacle lens holding shaft which can rotate in a fashion capable of angle encoding, can be adjusted radially and axially relative to the grinding wheel and can be locked, an angle sensor for acquiring the angle of rotation (φ n ) of the spectacle lens holding shaft, a position sensor for acquiring the radial distance (X n ) of the spectacle lens holding shaft from the grinding wheel, a position sensor for acquiring the axial position (Z n ) of the spectacle lens holding shaft with reference to the grinding wheel, and an input device for inputting coordinates (X 1 , Y 1 ; X 2 , Y 2 ) of the holes into the computer. 
     By virtue of the fact that the marking or drilling device is arranged on the spectacle lens edging machine, it can be controlled by the same computer which is also used to control the form grinding of spectacle lenses. 
     The marking or drilling device can be arranged such that it can be telescoped in the X-direction either in a niche of the grinding chamber or outside the grinding chamber, in the first case the spectacle lens to be marked or drilled being held at that point in the spectacle lens holding shaft at which the form grinding is also carried out while, in the second case, a holder is to be provided for a spectacle lens, which is to be marked or drilled, outside the grinding chamber on the spectacle lens holding shaft. 
     When the marking or drilling device is coupled in terms of movement to the spectacle lens holding shaft or the grinding wheel in the X-direction and Z-direction, the positioning of the marking or drilling device with reference to the spectacle lens held by the spectacle lens holding shaft can be performed by the computer in a fashion controlled as a function of the input coordinates of the holes, the same movement control being used for this purpose as also serves for the form grinding of the spectacle lens. 
     It is also advantageously possible to arrange the scanning device for the position of the bores in a spectacle lens or a pattern disk or a support disk on the spectacle lens edging machine, and to couple it in terms of movement to the spectacle lens holding shaft or the grinding wheel in the X-direction and Z-direction. In this case, a sensing arm can project radially into the region of the spectacle lens held by the spectacle lens holding shaft, of the pattern disk or the support disk, a sensing element which acts with or without contact being arranged on the sensing arm. 
     When the sensing element is designed as a sensing pin, this sensing pin can guided in the X-direction and Z-direction up to the respective bore in the spectacle lens or the pattern disk or support disk, which is brought into the region of the sensing element by rotating the spectacle lens holding shaft. The coordinates of the hole are recorded in this case and fed to the computer. 
     The sensing element can also be designed as an optoelectronic sensing device which is capable of recording the coordinates of a hole in a spectacle lens held by the spectacle lens holding shaft, a pattern disk or a support disk. 
     A linear, optoelectronic sensing device, for example a charge-coupled (CCD), linear image scanner can preferably be arranged on the sensing arm which, during a revolution of the spectacle lens holding shaft detects both the position of the bores and the circumferential contour of a spectacle lens, of a pattern disk or a support disk, and feeds them to the computer for controlling the form grinding and the marking and drilling of the holes. 
     The scanning device can be arranged both inside and outside the grinding chamber and serves simultaneously as a marking or drilling device when, for example, the sensing pin is simultaneously the drilling tool, or when the optoelectronic sensing device is designed as a laser device which, by controlling the intensity of the laser beam, can be used both as a scanning device and as a marking or drilling device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is explained in more detail below with the aid of a plurality of exemplary embodiments illustrated in the drawing, in which: 
     FIG. 1 shows a diagrammatic front view of a spectacle lens edging machine having a device for scanning the position of bores in a grinding wheel, outside the grinding-chamber, 
     FIG. 2 shows a cross section through a spectacle lens edging machine having a device for scanning and/or a device for marking or drilling holes in spectacle lenses, and 
     FIG. 3 shows a centering device set up for scanning the position of the bores in spectacle lenses, pattern disks or support disks. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The spectacle lens edging machine illustrated in FIG. 1 has a housing  1  with a grinding chamber  2  in which a pregrinding wheel  4 , which is arranged on a shaft  3  and has a cylindrical circumference, and two beveling grinding wheels  5 ,  6  with different beveling grooves are arranged. Arranged with its axis parallel to the shaft  3  with the grinding wheels  4 ,  5 ,  6  is a spectacle lens holding shaft made from two half shafts  7 ,  8 , of which the half shaft  7  can be axially displaced by means of a handle  9 , in order to clamp a rough cast lens (not illustrated). The grinding chamber  2  is closed during the grinding operation by means of a cover (not illustrated). 
     For the purpose of grinding, the shaft  3  with the grinding wheels  4 ,  5 ,  6  is set rotating rapidly, while a rough cast lens held by the spectacle lens holding shaft  7 ,  8  rotates slowly. The distance of the spectacle lens holding shaft  7 ,  8  from the shaft  3  with the grinding wheels  4 ,  5 ,  6  is controlled by a computer  10  in which control data for grinding the rough cast lens in accordance with the shape of a selected spectacle frame are stored. 
     Also arranged on the housing  1  are an input keyboard  11  and a screen  12 . The input keyboard  11  can be used to call spectacle lens contours stored in a known way, and to lead them to the controller of the spectacle lens edging machine for the purpose of spectacle lens machining. 
     It is also possible to use the input keyboard  11  to input personal data of the spectacle wearer, for example the pupil separation, the axis position of a cylindrical or prismatic cut of the spectacle lens, or the position of a reading portion. 
     A screen  12  is used to display the input data. It is also possible to illustrate on the screen  12  the circular rough cast lens and/or a spectacle lens which is to be form-ground in accordance with the input data. 
     An end  14  of the half shaft  8  is led out at the side of the housing  1 . Arranged on this end  14  is a holder in the form of pins  15 ,  16  of different diameters for a pattern disk  17 . The pattern disk has corresponding holes of corresponding diameter, and so it can be mounted on the projecting end  14  of the half shaft  8  only in a specific angular position. 
     Arranged on a holder  19  projecting from the housing  1  is a sensing arm  18  which can be telescoped and on whose free end in the region of the pattern disk  17  there is arranged a sensing element  20  which is illustrated here as a sensing pin. The sensing arm  18  can be moved in the direction of the arrow  23 , while the holder  19  can be moved in the direction of the arrow  24 . 
     By rotating the spectacle lens holding shaft  7 ,  8 , a bore  21  and a bore  22  are adjusted such that the sensing pin  20  can be inserted into the bore  21  or  22  by displacing the sensing arm  18  in the direction of the arrow  23  and displacing the holder  19  in the direction of the arrow  24 . The associated angle φ of the spectacle lens holding shaft  7 ,  8  is recorded by an angle sensor  13 , while the distance r of the bore  21  or  22  from the axis of the spectacle lens holding shaft  7 ,  8  is acquired by a position sensor (not illustrated) connected to the sensing arm  18 . The recorded coordinates of the bores  21  and  22  pass into the computer  10  and are displayed on the screen  12  in the image  17 ′ of the pattern disk  17  as images of the bores  21 ′ and  22 ′, respectively. Since the screen  12  is provided with a rectangular axis intersection  46 , the coordinates X 1 , Y 1  of the bore  22 ′ and the coordinates X 2 , Y 2  of the bore  21 ′ can be read off on the screen  12  and used to mark and/or drill appropriate holes in a spectacle lens held between the half shafts  7 ,  8  when the spectacle lens edging machine has an appropriate marking or drilling device. 
     The coordinates X 1 , Y 1  and X 2 , Y 2  for the bores  22 ′,  21 ′ can also be used for the purpose of driving a marking or drilling device separated from the spectacle lens edging machine, or to input the coordinates into such a marking or drilling machine by means of a keyboard or in another suitable way such as, for example, by means of a floppy disk, an EPROM, a barcode or a magnetic strip. 
     The holder  19  can also be coupled in terms of movement in the X-direction and Z-direction to the movement controller of the grinding wheels  4 ,  5 ,  6  with respect to the spectacle lens holding shaft  7 ,  8 , with the result that the movements of the holder  19  effect the recording of the coordinates of the holes  21 ,  22  via corresponding position pickups on the movement controller for the grinding wheels  4 ,  5 ,  6 . In this case, the sensing arm  18  can be permanently arranged on the holder  19 , although it is also possible that it can be telescoped from a idle position into an operating position. 
     In conjunction with coupling the movement to the grinding wheels  4 ,  5 ,  6 , the arrangement of the sensing arm such that it can be telescoped is particularly advantageous when the sensing device  18 ,  19 ,  20  is arranged (in a way that is not illustrated) in the grinding chamber  2 , and the sensing arm  18  is located in the idle position in a niche of the grinding chamber  2 . 
     Instead of a pattern disk  17 , it is also possible for a spectacle lens having fastening holes, or a support disk to be fastened on the projecting end  14  of the half shaft  8 , in order to acquire the position of the holes. 
     Instead of a sensing pin  20 , it is also possible to arrange an optoelectronic sensing element on the sensing arm  18 , in order to record the position of the holes  21 ,  22 . 
     When this optoelectronic sensing element is designed as a charge-coupled (CCD), linear image scanner, it is thereby possible to determine both the circumferential contour of a pattern disk  17  of a form-ground spectacle lens or of a support disk, and the position of the bores, and to use them to control the form grinding and the marking or drilling of the holes. 
     An already form-ground spectacle lens  25  which is held by the spectacle lens holding shaft  7 ,  8  is illustrated in the spectacle lens edging machine illustrated in FIG.  2 . 
     A guide  45  for a telescopic arm  27 , which supports a high-speed drill drive  26 , is arranged on a bearing neck  28  of a bearing support  38  for the shaft  3  of the grinding wheels  4 ,  5 ,  6 . Air turbines, combined air-water turbines or high-frequency electric motors are suitable as a drill drive. 
     Also fastened, by means of fastening screws  30 , on the bearing neck  28  is a spray guard  29  which encompasses the grinding wheels  4 ,  5 ,  6 . The bearing support  38  is connected to a slide part  32  of a compound slide  31 . The slide part  32  is guided by means of guide bars  33  in bores  34  in attachments  35  of a second slide part  36 . Guide rails  37  run at right angles to the guide bars  33  of the slide part  32 , with the result that the compound slide  31  can be displaced under computer control in the X-direction, that is to say in the direction of the guide bars  33 , and in the Z-direction, that is to say in the direction of the guide rails  37 . A drive motor  40 , which acts on the slide part  32  via an electromagnetic clutch  41 , is illustrated, and a position sensor  43  serves to monitor the positional control in the X-direction. A corresponding position&#39; sensor  44  serves to monitor the positional control in the Z-direction. Both the drives in the X-direction and Z-direction, and the corresponding position sensors  43 ,  44  are connected to the computer  10  via control lines  42 . 
     The compound slide  31  with the drives and position sensors  43 ,  44  is arranged in a machine subframe  39  which also supports the housing  1 . 
     The form grinding of the spectacle lens  25  is performed under the control of a computer by means of the computer  10 , with the use of a data record which is input into the computer and corresponds to the shape of the spectacle lens. 
     Before the form grinding, or after the form grinding, the bores  21 ″,  22 ″ can be made in the spectacle lens  25  by advancing the high-speed drill drive  26  on the telescopic arm  27  from an idle position (not illustrated), in which it is located in a niche of the grinding chamber  2 , into the operating position illustrated in FIG.  2 . 
     In the exemplary embodiment illustrated, the drill drive on the telescopic arm  27  with the guide  45  is coupled to the movement of the compound slide  31 . Consequently, the X-coordinate of the holes  21 ″,  22 ″ are set by moving the slide part  32  in accordance with the input coordinates. At the same time, the spectacle lens holding shaft  7 ,  8  is rotated in accordance with the position of the bore  21 ″ or  22 ″ such that the bore is situated on the vertical connecting line of the axes of the grinding wheel shaft  3  and the spectacle lens holding shaft  7 ,  8 , after which the slide part  36  is moved in the Z-direction and the drill drive  26  is set operating. A drilling tool on the drill drive  26  now drills the holes  21 ″,  22 ″ by virtue of the fact that the slide part  36  is imparted a corresponding feed movement. 
     When the telescopic arm  27  is arranged in a guide  45  which is not coupled in terms of movement to the compound slide  31 , but is fastened at a suitable point on the machine frame  39 , the drill drive  26  can be set to the X-coordinate  21 ″,  22 ″ by controlling the movement of the telescopic arm  27  by means of the computer  10 , without there being a need to move the compound slide  31  for this purpose. In this case, it must be possible to provide for an axial feed movement of the drilling tool on the drill drive  26  toward the spectacle lens  25  or, vice versa, for an axial movement of the spectacle lens  25  toward the drilling tool on the drill drive  26 . 
     It is also possible to use a laser drilling device instead of a drilling tool with a high-speed drill drive  26 . Moreover, it is possible to use the drilling device  26 ,  27  as scanning device for the position of the bores  21 ,  22  in a pattern disk when this pattern disk is clamped in the grinding chamber  2  between the half shafts  7 ,  8  and the drilling tool is used as sensing pin for insertion into the holes  21 ,  22  in a pattern disk  17 , or when, in the case of a laser drilling device, the laser beam is used to determine the position of the holes. 
     It is likewise possible for a spectacle lens or a support disk to be clamped between the half shafts  7 ,  8 , in order to scan the corresponding bores. 
     Furthermore, it is also possible for the scanning device  18 ,  19 ,  20  described with reference to FIG. 1 to be arranged in addition to the drilling device  26 ,  27  in the grinding chamber  2  of the spectacle lens edging machine when the scanning of the holes and the drilling are to be performed by means of separate devices. 
     Illustrated in FIG. 3 is a centering unit which has in a housing  47  a viewing optics  48  which can comprise a purely optical system or a screen. An image  17 ′ of a pattern disk  17  can be displayed in the viewing optics  48  by means of an electronic control unit  49 , which is arranged in a housing lower part  50  for ergonomic reasons, and an input keyboard  57 . This pattern disk  17  with the bores  21 ,  22  is mounted on support pins  52  of a carrier  51  and is held there by means of pins  54  on a hold-down  53 . The pattern disk  17  can be aligned with the support pins  52  such that the holes for the pins  15 ,  16  come to lie in a fashion illustrated with reference to the axis intersection  46 , and the bores  21 ,  22  appear as images  21 ′,  22 ′ in the viewing optics  48  in a fashion positionally accurate with reference to the axis intersection  46 . A cursor  58  can now be moved relative to the images  21 ′,  22 ′ of the bores by means of the keyboard  57 , and the position or the coordinates can be recorded by clicking. 
     This cursor  58  can, of course, also be moved by means of a computer mouse, and the coordinates of the bores  21 ,  22  can be recorded by clicking. 
     The coordinates X 1 , Y 1 ; X 2 , Y 2  can also be read off in the viewing optics  48  and noted down, or be recorded on suitable data media. 
     The centering device in accordance with FIG. 3 can be connected so as to exchange data with the spectacle lens edging machine in accordance with FIG. 2, with the result that the coordinates, determined in the centering device in accordance with FIG. 3, of the bores  21 ,  22  can be transmitted to the computer  10  of the spectacle lens edging machine and used there to control the drilling of the holes  21 ″,  22 ″. 
     The centering device in accordance with FIG. 3 is, moreover, used for the purpose of aligning a rough cast lens in a similar way as was described with reference to the pattern disk  17 , in accordance with which a swinging arm  55  with a holding part  56 , fastened thereon, in the form of a block or sucker is lowered onto the rough cast lens, and the holding part  56  is connected to the rough cast lens such that the rough cast lens can subsequently be inserted accurately in terms of position between the half shafts  7 ,  8  of the spectacle lens edging machine in accordance with FIG. 1 or FIG. 2, and can be form-ground. Such a centering device is described in DE 42 33 400 C1 of the same applicant. 
     The holes can then be drilled in the way described inside or outside a spectacle lens edging machine.