EP0281754A2 — Method and apparatus for making prescription eyeg…

Claim 1

Independent Claim 247 words

A machine for machining a blank in an eyeglass making process, said machine having a blank holder, a tool for cutting a blank held by said holder and having an axis of tool rotation, a means for driving said tool about said axis of tool rotation, and a ϑ coordinate drive means for continuously moving said holder and any blank attached to said holder relative to said tool in a ϑ coordinate direction about a Z axis, characterized in that said machine is operable to produce a surface on a blank related to a given eyeglass prescription and in that said machine further includes a Y coordinate drive means (24,26) for continuously moving said tool (50) relative to said holder (36) and any blank (38,92) attached to said holder in a Y coordinate direction along a Y axis extending perpendicular to and intersecting said Z axis, a Z coordinate drive means (24,26) for moving said tool relative to said holder and any blank attached to said holder in a Z coordinate direction along said Z axis, and a control means (16) for controlling said Z coordinate drive means in response to data corresponding to a given eyeglass prescription and in response to the instantaneous position of said holder relative to said tool about said ϑ coordinate axis and the instantaneous position of said holder relative to said tool along said Y coordinate axis so that said tool cuts a surface on said blank related to said prescription.

Claim 2

Dependent Claim 247 words

A machine for machining a blank in an eyeglass making process, said machine having a blank holder, a tool for cutting a blank held by said holder and having an axis of tool rotation, a means for driving said tool about said axis of tool rotation, and a ϑ coordinate drive means for continuously moving said holder and any blank attached to said holder relative to said tool in a ϑ coordinate direction about a Z axis, characterized in that said machine is operable to produce a surface on a blank related to a given eyeglass prescription and in that said machine further includes a Y coordinate drive means (24,26) for continuously moving said tool (50) relative to said holder (36) and any blank (38,92) attached to said holder in a Y coordinate direction along a Y axis extending perpendicular to and intersecting said Z axis, a Z coordinate drive means (24,26) for moving said tool relative to said holder and any blank attached to said holder in a Z coordinate direction along said Z axis, and a control means (16) for controlling said Z coordinate drive means in response to data corresponding to a given eyeglass prescription and in response to the instantaneous position of said holder relative to said tool about said ϑ coordinate axis and the instantaneous position of said holder relative to said tool along said Y coordinate axis so that said tool cuts a surface on said blank related to said prescription.

Claim 3

Dependent Claim 45 words

A machine for machining a blank as defined in claim 1 further characterized by said tool (50) having a spherical cutting surface (52), and said axis (A) about which said tool is rotated passing through the center (54) of curvature of said spherical cutting surface.

Claim 4

Dependent Claim 52 words

A machine for machining a blank as defined in claim 1 further characterized by said surface cut by said tool on the blank (92) held by said holder (36) being a lap surface usable to finish on a lens blank (38) a lens surface giving said lens blank characteristics satisfying said prescription.

Claim 5

Dependent Claim 45 words

A machine for machining a blank as defined in claim 1 further characterized by said surface cut by said tool on the blank (38) held by said holder being a lens surface on a lens blank giving said lens blank shape characteristics satisfying said prescription.

Claim 6

Dependent Claim 99 words

A machine for machining a blank as defined in claim 1 further characterized by said control means (16) also being operable to control said O coordinate drive means and said Y coordinate drive means in relation to one another so that, throughout a major portion of the travel of said tool along said Y axis and in cutting engagement with said blank, said blank moves at a sub stantially constant tangential velocity relative to said tool and said tool moves along said Y axis by a substantially constant distance for each revolution of said blank relative to said tool.

Claim 7

Dependent Claim 127 words

A machine for machining a blank as defined in claim 1 further characterized by said control means (16) being selectively operable to control said Z coordinate drive means in either a lap cutting mode in which said tool is caused to cut a lap surface on the blank (92) held by said holder or in a lens cutting mode in which said tool is caused to cut a lens surface on the blank (38) held by said holder, said lap surface and said lens surface for a given eyeglass prescription being the reverse of one another except for said lap surface being compensated for the thickness of a finishing pad, if any, which may be attached to it in a subsequent procedure for finishing said lens surface.

Claim 8

Dependent Claim 138 words

A machine for machining a blank as defined in claim 6 and for use with either lap blanks or lens blanks and wherein all of the blanks included in one of said categories of blanks each include a feature (74) distinguishing it from the blanks of the other category, detector means (76) for sensing a blank mounted on said blank holder to detect the presence or absence of said feature on said mounted blank, and means (82) responsive to said detector means for causing said control means to control said Z coordinate drive means in said lens cutting mode only when a lens blank is attached to said holder and to cause said control means to control said Z coordinate drive means in said lap surface cutting mode only when a lap blank is attached to said holder.

Claim 9

Independent Claim 246 words

The method for generating a surface on a blank in an eyeglass producing process which includes the steps of providing information constituting an eyeglass prescription, providing a blank, and rotating said blank continuously about said Z axis, further characterized by converting said information to point data describing a surface related to said prescription in terms of y, z and ϑ coordinates for all points of a set of points distributed over said surface, said y and z coordinates being linear displacements from a zero reference point measured along linear Y and Z axes perpendicular to one another and said ϑ coordinates being angular displacements from a reference plane containing said Z axis, moving a cutting tool (50) in cutting engagement with said blank (38,92) continuously along said Y axis so that said tool follows a generally spiral cutting path relative to said blank, repeatedly determining the instantaneous actual y and ϑ coordinates of said blank relative to said tool, and moving said cutting tool and blank relative to one another along said Z axis in response to said instantaneous actual y and ϑ coordinates and with reference to said point data so that the Z coordinate position of said blank relative to said tool takes on at each instant an actual value substantialy equal to the commanded value thereof given by said point data for a point having in said point data Y and ϑ coordinates substantialy equal to said instantaneous actual Y and ϑ coordinates.

Claim 10

Independent Claim 246 words

The method for generating a surface on a blank in an eyeglass producing process which includes the steps of providing information constituting an eyeglass prescription, providing a blank, and rotating said blank continuously about said Z axis, further characterized by converting said information to point data describing a surface related to said prescription in terms of y, z and ϑ coordinates for all points of a set of points distributed over said surface, said y and z coordinates being linear displacements from a zero reference point measured along linear Y and Z axes perpendicular to one another and said ϑ coordinates being angular displacements from a reference plane containing said Z axis, moving a cutting tool (50) in cutting engagement with said blank (38,92) continuously along said Y axis so that said tool follows a generally spiral cutting path relative to said blank, repeatedly determining the instantaneous actual y and ϑ coordinates of said blank relative to said tool, and moving said cutting tool and blank relative to one another along said Z axis in response to said instantaneous actual y and ϑ coordinates and with reference to said point data so that the Z coordinate position of said blank relative to said tool takes on at each instant an actual value substantialy equal to the commanded value thereof given by said point data for a point having in said point data Y and ϑ coordinates substantialy equal to said instantaneous actual Y and ϑ coordinates.

Claim 11

Dependent Claim 52 words

The method defined in claim 8 further characterized by providing as said tool a rotary cutting tool having a spherical cutting surface (52), and said step of rotating said tool being performed by rotating said tool about an axis (A) passing through the center (54) of curvature of said spherical cutting surface.

Claim 12

Dependent Claim 47 words

The method defined in claim 8 further characterized by said point data being data defining a lap surface (94) having a shape suitable for finishing a lens surface on a lens blank (38) which lens surface has shape characteristics causing said lens blank to satisfy said prescription.

Claim 13

Dependent Claim 45 words

A method defined in claim 8 further characterized by said surface defined by said point data being a lens surface having such shape that when it is generated on a lens blank (38) it causes said lens blank to have shape characteristics satisfying said prescription.

Claim 14

Dependent Claim 114 words

The method defined in claim 8 further characterized by said step of continuously moving said tool along said Y axis being performed by moving said tool along said Y axis at a substantially constant rate during the major portion of its travel along said Y axis in cutting engagement with said blank, and said step of rotating said blank continuously about said O axis being carried out by rotating said blank at a rate which is dependent on the position of said tool along said Y axis so that the tangential speed of said blank relative to said tool as said tool moves along said major portion of said Y axis remains substantialy constant.

Claim 15

Dependent Claim 86 words

The method defined in claim 8 further characterized by said step of converting said prescription information into surface defining point data being performed by providing a computer data base storing a multitude of individually selectable blocks of data each of which blocks of data contains point data defining a surface corresponding to a specific set of prescription information, and then when given a set of prescription information selecting from said data base a block of data whose identifying presciption information closely matches said given presciption information.

Claim 16

Dependent Claim 109 words

The method defined in claim 8 further characterized by said step of converting said given prescription information into surface defining point data being performed by providing a data base storing a multitude of individually selectable blocks of data each of which blocks of data includes a plurality of control points located on a surface corresponding to a set of prescription information identifying said block of data, providing a computer including means for generating from a set of surface defining control points the coordinates of surface defining points located along the path of said tool relative to said blank at much smaller displacements from one another than said control points.

Claim 17

Dependent Claim 48 words

The method defined in claim 8 further characterized by said step of converting said prescription defining information into surface defining point data being performed by providing a computer programmed to originate the required point data in response to the input thereto of a given set of prescription information.

Claim 18

Independent Claim 139 words

A method for producing a plurality of eyeglass lenses each having a lens surface shaped to give it characteristics satisfying an associated eyeglass prescription which may vary from lens to lens, said method including the following steps which are performed each time a new lens is wanted providing a lens blank, providing a lap blank, and providing prescription information specifying characteristics wanted in the lens to be produced from said lens blank, characterized by using said prescription information to generate on said lap blank (92) a lap surface (94) accurately related in shape to the reverse of a lens surface (44) needed on said lens blank (38) to cause said lens blank to satisfy said prescription information, and using said lap surface (94) to finish and polish a lens surface (44) such as foresaid on said lens blank (38).

Claim 19

Independent Claim 139 words

A method for producing a plurality of eyeglass lenses each having a lens surface shaped to give it characteristics satisfying an associated eyeglass prescription which may vary from lens to lens, said method including the following steps which are performed each time a new lens is wanted providing a lens blank, providing a lap blank, and providing prescription information specifying characteristics wanted in the lens to be produced from said lens blank, characterized by using said prescription information to generate on said lap blank (92) a lap surface (94) accurately related in shape to the reverse of a lens surface (44) needed on said lens blank (38) to cause said lens blank to satisfy said prescription information, and using said lap surface (94) to finish and polish a lens surface (44) such as foresaid on said lens blank (38).

Claim 20

Dependent Claim 67 words

A method as set forth in claim 16 further characterized by said step of using said prescription information to generate a lap surface on said lap blank being performed by placing said lap blank (92) in a data controlled cutting machine (14), and then operating said machine under the control of said prescription information to cause said machine to cut said lap surface on said lap blank.

Claim 21

Dependent Claim 79 words

A method as defined in claim 16 further characterized by, each time a new lens is wanted, using said prescription information to also generate a gray lens surface on said lens blank (38) which gray lens surface has a shape causing said lens blank to satisfy, except for the surface quality of said gray lens surface, said prescription information and which gray lens surface is the one subsequently finished and polished using said lap surface of said lap blank.

Claim 22

Dependent Claim 62 words

A method as set forth in claim 18 further characterized by said step of generating a gray surface on said lens blank being performed by placing said lens blank in a data contolled cutting machine (14), and then operating said cutting machine under the control of said prescription information to cause said machine to cut said lens surface on said lens blank.

Claim 23

Dependent Claim 98 words

A method as defined in claim 19 further characterized by said step of using said prescription information to generate a lap surface (94) on said blank (92) being performed by placing said lap blank in a data controlled cutting machine (14), and then operating said machine under the control of said prescription information to cause said machine (14) to cut said lap surface on said lap blank, and using the same data controlled cutting machine (14) to cut both said lap surface (94) on said lap blank (92) and said lens surface (44) on said lens blank (38).

Claim 24

Dependent Claim 167 words

A method as defined in claim 16 further characterized by said step of providing a lap blank being performed by selecting said lap blank from a set of lap blanks, and said step of providing a lens blank being performed by selecting said lens blank from a set of lens blanks, the blanks making up one of said sets being distinguishable from the blanks of the other set by virtue of each of said blanks of said one set having a feature (74) distinguishing it from the blanks of the other set, said cutting machine (14) being operable in response to said prescription information in either a lap blank cutting mode or a lens blank cutting mode, sensing the blank placed in said cutting machine to detect the presence or absence of said distinguishing feature (74) on said blank, and using the results of said detection to influence the operation of said cutting machine in either said lap blank cutting mode or said lens blank cutting mode.

Claim 25

Dependent Claim 89 words

A method as defined in claim 21 further characterized by said data controlled cutting machine including an operator manipulatable mode selection means (88) for selectively setting said machine in either said lap blank cutting mode or said lens blank cutting mode, and said step of using said results of said sensing step being performed by using said results to inhibit the operation of said cutting machine in the event the cutting mode selected by said mode selection means disagrees with the type of blank sensed by said sensing means.

Claim 26

Dependent Claim 89 words

A method as set forth in claim 16 further characterized by said step of using said prescription information to generate a lap surface (94) on said lap blank (92) being performed by first using said prescription information to generate a gray lens surface (44) on said lens blank (38) having a shape causing said lens blank to satisfy, except for the quality of said gray lens surface, said prescription information, and then using said gray lens surface (44) to form said lap surface (94) on said lap blank (92).

Claim 27

Dependent Claim 61 words

A method as defined in claim 23 further characterized by said step of using said gray lens surface on said lens blank to form said lap surface on said lap blank being performed by attaching an abrasive pad to said gray lens surface and then using said lens blank and abrasive pad to grind said lap surface into said lap blank.

Claim 28

Dependent Claim 67 words

A method as defined in claim 23 further characterized by said step of providing a lap blank and said step of using said prescription information to generate a lap surface on said lap blank being performed by molding said lap blank in a molding process which uses said gray lens surface as a mold surface defining the shape of said lap surface on the molded lap blank.

Claim 29

Dependent Claim 89 words

A method as defined in claim 23 further characterized by said step of providing a lap blank and said step of using said prescription information to generate a lap surface on said lap blank being performed by applying a piece of sheet material (110) to said gray lens surface, and then molding said lap blank in a molding process which uses said gray lens surface as augmented by said piece of sheet material as a mold surface defining the shape of said lap surface on the molded lap blank.

Claim 30

Dependent Claim 59 words

A method as defined in claim 26 further characterized by said step of using said lap surface to finish and polish said lens surface involving the step of attaching an abrasive pad (96) to said lap surface, and said piece of sheet material applied to said lens surface having a thickness substantially equal to that of said abrasive pad.

Claim 31

Dependent Claim 37 words

A method as defined in claim 26 further characterized by said piece of sheet material (110) being an abrasive pad which in said molding process becomes part of said molded lap blank and forms said lap surface.

Claim 32

Dependent Claim 148 words

A method as defined in claim 23 further characterized by said step of providing a lap blank and said step of using said prescription information to generate a lap surface on said lap blank being performed by fixing an abrasive pad to said gray lens surface, and then moving said lens blank and said lap blank relative to one another to cause said abrasive pad to grind said lap surface into said lap blank, and said step of using said lap surface to finish and polish a lens surface being performed by removing said abrasive pad from said gray surface of said lens blank, fixing an abrasive pad to said lap surface, and then lapping said gray surface of said lens blank by moving said lens blank and said lap relative to one another to cause said abrasive pad to refine said gray surface of said lens blank.

Claim 33

Dependent Claim 97 words

A method as defined in claim 16 further characterized by said step of providing a lens blank involving the step of providing a lens blank having two major lens surface which together provide said lens blank with characteristics closely matching those specified by said prescription information, and using said lap surface to reshapingly grind one of said major lens surfaces to give it a shape causing said lens blank to satisfy, except for the quality of said one lens surface, said prescription information, and then using said lap surface to finish and polish said one lens surface.

Claim 34

Independent Claim 167 words

The method of surfacing an eyeglass lens blank to make it satisfy a given set of prescription information, said method the steps of providing a set of prescription information, and providing a lens blank having two major lens surfaces, characterized by converting said set of prescription information into machine control data, placing said lens blank (38) in a data controlled cutting machine (14) and operating said machine in response to said machine control data to machine one of said major surfaces of said lens blank to transform it into a machined gray surface (44) having a basic shape causing said blank, except for the quality of said gray surface, to satisfy said prescription information, providing a lap (92) having a lap surface (94) with a shape related to that of said gray lens blank surface, and then lapping said gray lens blank surface with said lap surface and an interposed abrasive to bring said gray lens blank surface to a polished quality while retaining said basic shape.

Claim 35

Independent Claim 167 words

The method of surfacing an eyeglass lens blank to make it satisfy a given set of prescription information, said method the steps of providing a set of prescription information, and providing a lens blank having two major lens surfaces, characterized by converting said set of prescription information into machine control data, placing said lens blank (38) in a data controlled cutting machine (14) and operating said machine in response to said machine control data to machine one of said major surfaces of said lens blank to transform it into a machined gray surface (44) having a basic shape causing said blank, except for the quality of said gray surface, to satisfy said prescription information, providing a lap (92) having a lap surface (94) with a shape related to that of said gray lens blank surface, and then lapping said gray lens blank surface with said lap surface and an interposed abrasive to bring said gray lens blank surface to a polished quality while retaining said basic shape.

Claim 36

Dependent Claim 60 words

The method of surfacing an eyeglass lens blank as defined in claim 31 further characterized by said step of providing a lap being performed by providing a lap blank, and placing said lap blank in a data controlled cutting machine and operating said machine in response to said machine control data to machine said lap surface on said lap blank.

Method and apparatus for making prescription eyeglass lenses

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