Preformed Block Piece With Three Points of Support

Abstract

The invention relates to a block piece for holding an optical lens to be machined, with a coupling part for holding in a workpiece chuck and with a holding part for fastening the lens. The holding part has a convex or concave holding surface corresponding to a first side of the lens. The holding surface is, according to the shape of the lens to be held, provided in the form of a negative free-forming surface, and the block piece is made from a plastic that can be machined.

1 . A block piece for the holding of an optical lens being machined, comprising: a coupling part, having an axis of rotation, for holding in a workpiece chuck, and a holding part adapted for securing the lens, wherein the holding part has a convex or concave holding surface corresponding to a first side of the lens,
 wherein the holding surface, according to a shape of the first side of the lens being held, is configured as an aspherical, toroidal, progressive or asymmetrical negative surface and the block piece is made of a machinable plastic.   
   
   
       2 . The block piece according to  claim 1 ,
 wherein a principal axis of the holding surface is arranged set off from or tilted to or both set off and tilted to the axis of rotation of the coupling part.   
   
   
       3 . The block piece according to  claim 1 ,
 wherein the holding surface has several pointlike support locations for the lens being held, and the remaining part of the holding surface is somewhat set back relative to the support locations.   
   
   
       4 . The block piece according to  claim 3 ,
 wherein the remaining set-back part of the holding surface has approximately the shape of the first side of the lens being held.   
   
   
       5 . The block piece according to  claim 3 ,
 wherein the pointlike support locations of the holding surface form part of an imaginary surface, and the imaginary surface describes the shape of the first side of the lens being held.   
   
   
       6 . The block piece according to  claim 1 ,
 wherein at least one channel for a pressurizing agent is provided between the holding surface and an outer surface, by which the pressurizing agent from an outside can be brought into a region between the holding surface and the lens being held.   
   
   
       7 . The block piece according to  claim 6 ,
 wherein at least one equalizing channel is provided in the holding surface to receive excess adhesive.   
   
   
       8 . The block piece according to  claim 7 ,
 wherein the equalizing channel or the pressurizing agent channel or a combination thereof is configured in star, spiral, or circle shape or a combination thereof.   
   
   
       9 . The block piece according to  claim 6 ,
 wherein the pressurizing agent channel has a cross section widening in the direction of flow of the pressurizing agent.   
   
   
       10 . The block piece according to  claim 6 ,
 wherein several pressurizing agent channels are uniformly distributed and issue onto the holding surface.   
   
   
       11 . The block piece according to  claim 6 ,
 wherein the pressurizing agent channel has a funnel-like mouth region.   
   
   
       12 . The block piece according to  claim 6 ,
 wherein the pressurizing agent channel emerges centrally, in the region of a center axis of the holding surface and/or in the region of the pointlike support locations.   
   
   
       13 . The block piece according to  claim 1 ,
 wherein the block piece is configured as an injection molded plastic part.   
   
   
       14 . The block piece according to  claim 1 ,
 wherein the holding surface or at least the pointlike support locations of the holding surface can be activated in order to generate an adhesive force and possess adhesive properties.   
   
   
       15 . The block piece according to  claim 1 ,
 wherein a double-sided adhesive film to secure the lens is applied to the holding surface at least in the region of the pointlike support locations.   
   
   
       16 . The block piece according to  claim 1 ,
 wherein the block piece is configured at least in two parts.   
   
   
       17 . A method for placing an optical lens, with a first side and a second side being machined, on a block piece made of plastic, with a coupling part for a workpiece chuck and a holding part with a holding surface for the lens, comprising the steps of:
 a) placing an adhesive on the holding surface and/or the lens and/or the holding surface is activated in order to develop an adhesive force,   b) orienting the holding surface of the block piece and the first side of the lens to each other in terms of their respective axial position,   c) joining the first side and the holding surface and thus forming a pair of block piece and lens, and   d) before being placed on the block, machining the holding surface, thus generating a negative form corresponding to the first side of the lens.   
   
   
       18 . The method according to  claim 17 ,
 wherein the holding surface is machined in such a way as to generate several pointlike support locations for the lens being held, wherein a portion of the holding surface stand somewhat back from the support locations, and the pointlike support locations of the holding surface form part of an imaginary surface which describes the form of the first side of the lens being held and the setback part describes only approximately the form of the lens being held.   
   
   
       19 . The method according to  claim 17 ,
 wherein the adhesive is applied to the support locations in the form of a spiral, star, or point or a combination thereof.   
   
   
       20 . The method according to  claim 17 ,
 further including the steps of hardening the adhesive by using thermal radiation or UV radiation or a combination thereof.   
   
   
       21 . The method according to  claim 17 ,
 wherein the adhesive is configured as a double-sided adhesive film and it is brought to bear against the holding surface and the lens.   
   
   
       22 . The method according to  claim 17 ,
 further including the steps of working at least one equalizing channel into the holding surface before or after the machining of the holding surface per step a), to receive excess adhesive.   
   
   
       23 . The method according to  claim 17 ,
 wherein at least one recess fashioned as a pressurizing agent channel is worked into the block piece before or after the machining of the holding surface per step a), ensuring communication between the holding surface and the surroundings.   
   
   
       24 . The method according to  claim 20 ,
 wherein the hardening of the adhesive in terms of duration and/or intensity occurs in such a way that the adhesive is basically only hardened completely in the region between the lens and the holding surface and it is not hardened in the region of the equalizing channel and/or the pressurizing agent channel.   
   
   
       25 . The method according to  claim 17 ,
 further including the steps of machining or polishing or a combination thereof of a second side of the lens occurs after connecting the lens to the block piece.   
   
   
       26 . The method according to  claim 17 ,
 wherein the pair of block piece and lens is clamped in an additional workpiece chuck for the polishing of the lens.   
   
   
       27 . The method according to  claim 17 ,
 further including the steps of coating the lens on the block occurs after the machining or polishing of the lens or a combination thereof.   
   
   
       28 . The method according to  claim 27 ,
 further including the steps of machining or polishing the marginal zone R of the pair of block piece and lens after the coating of the lens.   
   
   
       29 . The method according to  claim 27 ,
 wherein at least one pair of block piece and lens is placed in an additional block piece holder for the coating of the lens.   
   
   
       30 . The method according to  claim 17 ,
 wherein pressurizing agent for deblocking the lens is introduced via the pressurized agent channel between the first side of the lens and at least the pointlike support locations of the holding surface of the block piece.   
   
   
       31 . The method according to  claim 17 ,
 wherein the adhesive and/or the lens is heated or cooled for the deblocking or loosening of the lens or a combination thereof.   
   
   
       32 . A method for deblocking an optical lens from a block piece made of plastic, with a coupling part for a workpiece chuck and a holding part, on whose holding surface the lens is placed, comprising the steps of:
 for the deblocking or loosening of the lens or a combination thereof, deforming the remaining holding part or the coupling part of the block piece or a combination thereof so that the holding surface is deformed and at least partly loosened from the lens.   
   
   
       33 . The method according to  claim 32 ,
 further including the steps of providing the holding part or the coupling part of the block piece or a combination thereof with at least one slot prior to the deforming.   
   
   
       34 . The method according to  claim 33 ,
 further including the steps of subjecting the holding part or the coupling part or a combination thereof to a clamping force in a direction transverse to the slot for purposes of deformation.