Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B13/00—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B13/00—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor
  • B24B13/02—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor by means of tools with abrading surfaces corresponding in shape with the lenses to be made
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D9/00—Wheels or drums supporting in exchangeable arrangement a layer of flexible abrasive material, e.g. sandpaper
  • B24D9/08—Circular back-plates for carrying flexible material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S451/00—Abrading
  • Y10S451/921—Pad for lens shaping tool

Definitions

• the invention relates to the surfacing of optical surfaces.
• Surfacing means any operation to modify the surface condition of a previously shaped optical surface. These include polishing, grinding or etching operations to modify (decrease or increase) the roughness of the optical surface and / or to reduce the undulation.
• the invention relates to a tool for surfacing an optical surface, which comprises a rigid support having a transverse end surface, an elastically compressible interface which is applied against and covers said end surface, and a flexible pad suitable for to be applied against the optical surface and which is applied against and at least partially covers the interface opposite and to the right of said end surface.
• the tool In order to reduce the roughness of the optical surface, the tool is brought into contact with the latter while maintaining sufficient tool pressure on it so that, by deformation of the interface, the pad conforms to the shape of the optical surface. .
• the optical surface While watering the optical surface with a fluid, it is rotated relative to the tool (or reciprocally) and is scanned by means of the latter.
• the optical surface is rotated, its friction against the tool being sufficient to jointly drive it in rotation.
• the surfacing operation requires an abrasive that can be contained in the buffer or in the fluid.
• the elastically compressible interface makes it possible to compensate for the difference in curvature between the end surface of the tool support and the optical surface, so that the same tool is suitable for a range of surfaces. optical curvatures and different shapes.
• the transverse extent of the tool is comparable to the extent of the optical surface, which is generally the case for surfacing ophthalmic lenses, the range of optical surfaces that the same tool is able to plan is relatively limited .
• this type of tool is particularly poorly suited to surfacing optical surfaces of complex shapes, called "freeform" in English, particularly aspherical, which by definition have a non-uniform curvature.
• this type of tool is also poorly suited to optical surfaces having a convexity or concavity gap that is too pronounced relative to the tool: in the first case, the edges of the tool lose contact with the optical surface. ; in the second case, it is the central part of the tool that loses contact with the optical surface, resulting in incomplete surfacing.
• a first is to reduce the diameter of the tool, that is to say, its overall transverse dimension, so as to restrict and locate the portion of the optical surface in contact with the tool. On such a portion located in fact, the contact of the tool with the surface remains more homogeneous than considering this optical surface taken as a whole.
• this restriction of the diameter of the tool is accompanied by a decrease in its "lift” or “sitting” and, consequently, its stability on the optical surface during surfacing.
• optical surface manufacturers and in particular ophthalmic lens manufacturers, are resigned to using a large number of different tools, sizes and bends to cover the range of their surfaces. optics.
• the invention aims in particular to overcome the aforementioned drawbacks by proposing a surfacing tool which, while being adapted to a range of optical surfaces sufficiently large, in terms of curvatures (convexity, concavity) and shapes (spherical, toric, aspherical, progressive or any combination thereof, or more generally "freeform"), has good stability during surfacing, and allows surfacing at once safe, fast and of good quality while being of reduced cost.
• the invention proposes a tool for surfacing an optical surface, which comprises a rigid support having a transverse end surface, an elastically compressible interface which is applied against and covers said end surface, as well as a flexible pad adapted to be applied against the optical surface and which is applied against and covers at least part of the interface opposite and to the right of said end surface, characterized in that the buffer comprises a so-called central portion which lies at the right of said end surface and a so-called peripheral portion which is transversely beyond said end surface while resilient return means are provided which, to connect this peripheral portion to the support, a collar flat or curved fixed rigidly, on the inner side, to the support and having a continuous peripheral portion cooperating with support, directly or by via the only interface, with said peripheral portion of said buffer, a means for stabilizing the tool during surfacing being formed by said return means and by said peripheral portion of the buffer, said tool being adapted to perform a surfacing essentially at said central portion of said buffer.
• the same tool is suitable for surfacing surfaces whose convexity - or concavity - has a relatively pronounced deviation from that of the tool, and is particularly suitable for surfacing surfaces of complex shape, especially toro-progressive or toro-degressive. It is thus possible to cover the whole of a given range of lenses with a variety of tools (curvature, concavity, convexity) and, therefore, a fleet of tools restricted to the benefit of costs, including logistics.
• said flange is flexible and protrudes transversely of the support.
• said flange is formed by a solid wall.
• said flange is formed by a perforated wall.
• - said collar is perforated by windows of generally trapezoidal shape; and optionally - two said consecutive windows are separated by a strip of material with parallel edges; and / or - the boundary between each said window and said continuous peripheral portion is in an arc.
• - said flange is part of a wafer further comprising a solid portion surrounded by said flange; and optionally - said solid part is circular; and / or - said solid part has holes for passage of the rod of a fixing screw.
• the interface comprises a central portion which is at the right of the end surface of the support, and a peripheral portion, which is transversely beyond this end surface, and which is interposed between the peripheral portion of the buffer and the return means.
• the peripheral portion of the interface is, for example, in the absence of stress, in the form of a ring surrounding its central portion.
• the interface is monobloc, its central and peripheral parts forming a single piece, to the benefit of simplicity of implementation.
• the interface is for example, in the absence of constraint, in the form of a disk.
• the buffer can be monobloc, its central and peripheral parts forming a single piece, for the benefit of simplicity of implementation.
• the pad has a plurality of petals projecting transversely from its central portion, which corresponds to the usual form in which the surfacing pads are made.
• the peripheral portion is in the form of a ring surrounding the central portion, so that when the buffer is monoblock, it is, in the absence of stress, in the form of a disc.
• the end surface it can be flat, concave or convex, which allows, with a small number of tools, to surface a large number of optical surfaces.
• FIG. 1 is an exploded perspective view of a tool according to the invention, a receiving base of the tool and a lens; ophthalmic having an optical surface to be surfaced;
• FIG. 2 is an elevation view in section of the base of the ophthalmic lens and of the tool of FIG. 1, which is shown assembled, at rest, in place on the spindle;
• - Figure 3 is a view similar to Figure 2, but during the surfacing rather than at rest;
• FIG. 4 is a diagrammatic view from above showing an ophthalmic lens being surfaced by means of a tool according to the invention, the tool being represented during the scanning of the optical surface in two positions of which the one is illustrated in broken lines.
• a tool 1 for surfacing an optical surface 2 in this case one of the faces of an ophthalmic lens 3, which is here concave.
• the tool 1 is formed of a stack of at least three parts, namely a rigid portion 4, an elastically compressible portion 5, and a flexible portion 6, which, in what follows, will be called respectively support, interface and buffer.
• the support 4 is generally cylindrical with symmetry of revolution and has an axis of symmetry denoted X, which defines a so-called longitudinal direction.
• the support 4 is designed to cooperate in the manner of a hub with the rocket
• the spindle 7 located at the end of the spindle 8 that comprises a base 9 for receiving the tool 1.
• the spindle 7 has a conical general contour whose end is rounded.
• a groove 10 shown in FIG. 1 only
• an elastic ring (not shown) fastened to the support 4 to hold the tool 1 at the base 9
• the support 4 has a blind hole 11 formed in the face 12 of the support 4 that is seen at the top in the drawings.
• the bottom of the hole 11 is rounded like the end of the rocket 7, to which it serves as a range.
• the remainder of the hole 11 is more flared than the side wall of the rocket 7, as can be seen in FIGS. 2 and 3.
• the support 4, and more generally the tool 1, when it is received on the base 9, can rotate freely with respect thereto about the axis X, coincides with that of the pin 8 or inclined up to about 30 degrees relative thereto.
• the support 4 Opposite its face 12 in which the hole 11 is made, the support 4 has an end surface 13 extended substantially transversely, against which is applied, covering the interface 5.
• the buffer 6 is as to applied against the interface 5 on the other side thereof relative to the support 4. More specifically, the buffer 6 covers at least part of the interface 5 opposite and to the right of the end surface 13.
• the friction of the pad 6 against the optical surface 2 will allow, by means of an abrasive contained in the watering fluid or incorporated in the pad 6 itself, to ensure a superficial removal of material on the optical surface 2 to modify the surface condition, as we will see later.
• the pad 6 has a central portion 6a which is at the right of the end surface 13, and a peripheral portion 14 which is, transversely, beyond the end surface 13.
• This peripheral portion 14 is connected to the support 4 via elastic return means 15.
• the peripheral portion 14 extends in the extension of the central portion 6a while being, at rest, substantially coplanar with it.
• the buffer 6 is in one piece, the peripheral portion 14 being connected to the central portion 6a, so that they form in fact one and the same piece.
• the tampon 6 is in the form of a flower, and thus comprises a plurality of petals 14b which protrude transversely from the central portion. 6a, form the peripheral portion 14 of the buffer 6 and each extend transversely beyond the end surface 13.
• the peripheral portion 14 is in the form of a crown that surrounds the central portion 6a.
• the buffer 6 is, when it is monobloc, in the form of a disc of material whose thickness is small in front of its diameter, as represented in FIG. the peripheral portion 14 thus forming a flange relative to the end surface 13.
• the return means 15, which will be described later, can be interposed directly between the support 4 and the peripheral portion 14 of the buffer 6, that is, that is to say, in practice, the collar whose periphery is illustrated in dotted line in Figure 1 or the petals 14b.
• the interface 5 comprises not only a central portion 5a which is at the right of the end surface 13, but also a peripheral portion 16 which is transversely beyond of the end surface 13.
• This peripheral portion 16 is in the extension of the central portion 5a, and is for example, in the absence of stress, in the form of a ring which surrounds the central portion 5a, and which is in fact interposed between the peripheral portion 14 of the buffer 6 and the return means
• the interface 5 is in one piece, its central portions 5a and 16 are in fact connected to form together a single piece, the peripheral portion 16 forming a collar relative to
• the monobioc interface is for example in the form of a disc of material whose thickness is small in front of its transverse dimension (that is, in the absence of stress). to say its diameter).
• the interface 5 and the buffer 6 are both monobloc, they have comparable transverse dimensions.
• they when they are each in the form of a disc of material, they will preferably be chosen, for constructive convenience, of the same diameter. But we can also provide to use a different diameter pad of the interface, especially greater diameter to mitigate the edge effects of the tool on the worked surface.
• the return means 15 are now described. These comprise an elastically flexible flange 18 which projects transversely from the support 4 and which is rigidly connected to the latter on the inner side while its peripheral part, which is continuous, co-operates in contact with the peripheral portion 14 of the buffer 6, through the peripheral portion 16 of the interface 5 in the preferred example illustrated, but this cooperation could just as easily be direct. In this way, under the effect of a force exerted longitudinally on the peripheral portion 14, the flange 18 is deformed by exerting on the peripheral portion 14 a reaction opposite to said force. According to the embodiment illustrated in Figures 1 to 3, the return means 15 are in fact in the form of a wafer rigidly fixed to the support 4.
• This wafer has a solid portion 19 extending between a central hole 20 and the flange 18, which is perforated by windows 21 situated between the solid part 19 and a solid continuous edge 22 which forms the peripheral part of the flange 18.
• its solid part 19 presents holes 23 for passage of the rod of a screw, corresponding threaded holes 24 being provided on the support 4, in the face 12.
• the collar 18 has, at rest, a frustoconical conformation while the solid part 19 is flat, as is the face 12 of the support 4, the wafer 15 being concave on the side of the support 4, the interface 5 and the buffer 6.
• the windows 21 formed in the collar 18 are regularly distributed and number of seven, they each have the same contour, which is generally trapezoidal. More specifically, the boundary between each window 21 and the border 22 is in an arc, and likewise for the boundary between each window 21 and the solid portion 19. The other sides of the windows 21 are oriented in one direction substantially radial, each strip of material located between two consecutive windows 21 having parallel edges.
• the wafer 15 is made of molded plastic material of constant thickness, small in front of its diameter.
• the buffer 6 and the interface 5 are both monoblock pieces, the interface 5 being in the form of a disk of material, the buffer 6 being in the form of a flower, while the return means 15 are in the form of a wafer as described above, the continuous peripheral edge 22 bears on the peripheral portion 16 of the interface 5 opposite the buffer 6.
• the diameters of the interface 5, the buffer 6 and the wafer 15 have a value at least twice that of the diameter of the support 4.
• the diameters of the interface 5 and the buffer 6 are chosen substantially equal to the diameter of the lens 3, so that the diameter of the support 4 is much smaller than the diameter of the lens 3.
• the use of the tool 1 is illustrated on FIGS. 2 to 4.
• the lens 3 is mounted on a rotary support (not shown) by means of which it is rotated about a fixed axis Y (FIG. 4).
• the tool 1 is applied against this face 2 with sufficient force so that the stamp 6 matches its shape, as shown in FIG. 3.
• the tool 1 is here, for its part, free to rotate while being however decentered by relative to the optical surface 2.
• a drive forced rotation of the tool, by own means, however, can be provided.
• the relative friction of the optical surface 2 and the buffer 6 is sufficient to rotate the tool 1 in the same direction as that of the lens 3, around the fuse 7.
• the optical surface 2 is sprayed with a fluid of non-abrasive or abrasive watering, depending on whether or not the buffer performs this function.
• the base 9 is moved during the surfacing along a radial path, the point of intersection of the axis of symmetry of the pin 8 with the optical surface 2 making a movement of back and forth between two cusp points, namely an internal cusp A and an external cusp B both located at a distance from the axis of rotation Y of the lens 3.
• the central portion 6a of the pad 6 is deformed by marrying the shape of the optical surface 2 thanks to the compressibility of the central portion 5a of the interface 5.
• peripheral portion 14 of the pad 6 deforms by marrying the shape of the optical surface 2 thanks to the deformation of the flange 18.
• the continuity of the peripheral edge 22 provides a certain circumferential regularity of the biasing force exerted, and therefore a certain regularity surfacing performed.
• peripheral portions 14 of the buffer 6 and 16 of the interface 5 they essentially have a stabilizing role, on the one hand thanks to the increase in the lift or seating of the tool 1 compared to a conventional tool whose buffer and the interface would be limited to the central portions 5a, 6a and, secondly, thanks to the return wafer 15 which maintains a permanent contact between the peripheral portion 14 of the buffer 6 and the optical surface 2. It follows that regardless of the location of the tool 1 on the optical surface 2 and regardless of its rotation speed, its axis of rotation X is permanently collinear or substantially collinear with the normal to the optical surface 2, the orientation of the tool 1 is thus optimal at all times. In the illustrated embodiment, the end surface 13 of the support 4 is flat.
• the tool 1 is thus adapted to surface a certain range of optical surfaces 2 of different curvatures.
• the flange 18 of the slab 15 is shaped differently. It is in particular curved in the same direction, but more (the interface 5 and the buffer 8 are then curved at rest with their convexity which is turned towards the support 4 and the wafer 15); flat at rest, that is to say coplanar with the central portion 19 (the interface 5 and the buffer 6 are then curved at rest as shown in Figure 3, that is to say with their concavity turned towards the support 4 and the wafer 15); or else with an inverted curvature, that is to say it is the convex side of the slab 15 which looks at the support 4, the interface 5 and the buffer 6 (the latter two are then curved at rest more than in Figure 3).
• This first variant is more particularly intended for convex optical surfaces while the illustrated embodiment and the other two variants are more particularly intended for concave optical surfaces.
• the end surface 13 of the support 4 rather than being flat, is convex, the tool then being intended for optical surfaces having a more pronounced concavity, or else the end surface 13 of the support 4 is instead concave, the tool then being intended for optical surfaces with pronounced convexity. It is of course possible to combine the concave or convex embodiment of the end surface 13 with different shapes of the slab 15 mentioned above.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Turning (AREA)
• Hooks, Suction Cups, And Attachment By Adhesive Means (AREA)
• Milling, Broaching, Filing, Reaming, And Others (AREA)
• Pens And Brushes (AREA)

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Applications Claiming Priority (2)

Publications (3)

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• 2003
  • 2003-07-16 FR FR0308670A patent/FR2857610B1/fr not_active Expired - Fee Related
• 2004
  • 2004-07-12 WO PCT/FR2004/001828 patent/WO2005007340A2/fr active IP Right Grant
  • 2004-07-12 PL PL04767659T patent/PL1644160T3/pl unknown
  • 2004-07-12 AT AT04767659T patent/ATE372854T1/de not_active IP Right Cessation
  • 2004-07-12 CN CNB2004800203142A patent/CN100537139C/zh active Active
  • 2004-07-12 ES ES04767659T patent/ES2293333T3/es active Active
  • 2004-07-12 KR KR1020067001036A patent/KR100795456B1/ko not_active IP Right Cessation
  • 2004-07-12 EP EP04767659A patent/EP1644160B8/de active Active
  • 2004-07-12 US US10/564,500 patent/US7223164B2/en active Active
  • 2004-07-12 AU AU2004256949A patent/AU2004256949B2/en not_active Ceased
  • 2004-07-12 CA CA2531960A patent/CA2531960C/fr not_active Expired - Fee Related
  • 2004-07-12 BR BRPI0412652-1A patent/BRPI0412652A/pt not_active IP Right Cessation
  • 2004-07-12 PT PT04767659T patent/PT1644160E/pt unknown
  • 2004-07-12 JP JP2006519952A patent/JP4410250B2/ja not_active Expired - Fee Related
  • 2004-07-12 DE DE602004008920T patent/DE602004008920T2/de active Active

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