TW201029797A - Lens processing method and grinding device - Google Patents

Abstract

Disclosed is a lens processing method and grinding device without using a centering device. A dual-spindle grinding machine that comprises a grinding wheel spindle installed with a grinding wheel for rough grinding and a grinding wheel spindle installed with a grinding wheel for fine grinding is used. A lens blank is mounted to a first dual-spindle grinding machine to carry out round and fine grinding operations on a first surface. Afterwards, the lens blank is transferred to a second dual-spindle grinding machine in order to use the second dual-spindle grinding machine to perform rough and fine grinding operations of a second surface and machining of an outer circumference. The retention rack of the first dual-spindle grinding machine is a retention rack of chuck structure, while the retention rack of the second dual-spindle grinding machine is a retention rack of suction structure. The second dual-spindle grinding machine uses the surface that has been subjected to fine grinding as a reference for holding the lens blank and carries out the rough and fine grinding operations of the second surface and the machining of the outer circumference under a condition of maintaining the holding state, so that centering of the lens blank can be realized through the machining of the outer circumference. Afterwards, polishing operations are performed on the first and second surfaces, and finally, cleaning of the polished lens is carried out.

Description

201029797 6. Technical Field of the Invention The present invention relates to a lens processing method and a grinding apparatus, and relates to the above-described rough grinding process including a spherical surface of a lens, a polishing process of a fine grinding process, and a centering process, which are suitable for lens processing. Method and device. [Prior Art] In the processing of a lens, it is necessary to perform rough grinding, fine grinding, and polishing of two spherical surfaces of the lens (hereinafter referred to as "first surface" and "second surface"). For the peripheral processing for centering (finding center), conventionally, a plurality of devices have been used for performing these processes. That is, the processing is performed by the following steps: the first surface and the second surface are roughened by the cup grinding wheel of the rough mill. Milling 'Using the abrasive discs of the refiner' to grind the first and second faces' polishing of the first and second faces using a polishing disc of a polishing machine', using a centering machine for peripheral processing, and then Cleaning is performed for rinsing the oily grinding fluid used in peripheral processing. _ Rough grinding is generally performed by a method called CG machining (spherical surface forming). That is, the lens blank is mounted on the workpiece axis in the vertical direction. a downward cup-shaped grinding wheel (cup-shaped grinding wheel) that is in circular contact with the surface of the lens description (accurately, in contact with a circle exposed from the periphery of the lens) is mounted on the lower end of the grinding wheel shaft, the grinding wheel Shaft fit to grind The curvature of the lens surface is tilted. The grinding wheel axis is positioned such that the contact circle of the cup-shaped grinding wheel with the lens surface passes right through the axis center of the lens. Then, the workpiece axis and the grinding wheel axis are rotated 'Using the servo motor to apply the workpiece shaft upward Cutting feed, through the synthetic movement of the cup-shaped grinding wheel relative to the surface of the lens and the rotation of the lens, the spherical surface of the lens is formed and processed. The cup-shaped grinding wheel for coarse grinding uses a particle size of about 1〇〇3 201029797~350. Grinding wheel On the other hand, fine grinding is a process of transferring the spherical surface of the abrasive disc to the lens. That is, the abrasive disc (a disc-shaped tool to which the abrasive grains for grinding is attached) is mounted on the swinging table. At the lower end of the upper grinding wheel shaft, the abrasive disc has a spherical surface corresponding to the curvature of the spherical surface of the lens to be processed, and the lens blank that has been rough-machined is mounted on the upper end of the workpiece shaft. Then, the swing center of the oscillating table is In a state where the center of curvature of the spherical surface of the lens is uniform, the lens surface is pressed against the abrasive disk by a cylinder or the like at a certain pressure, and the rotation φ and the reciprocating oscillation of the grinding wheel shaft are performed. Synthetic motion with the rotation of the workpiece axis, grinding the surface of the lens" in the 'lens grinding and fine grinding of the lens material is performed separately using separate equipment'. The applicant of the present application proposed a spherical grinding of the lens. The cutting method and apparatus (hereinafter referred to as "biaxial grinding machine") (Patent Document 1), in which the grinding wheel shaft for rough grinding and the grinding wheel shaft for fine grinding are provided in the same equipment, the thickness of the lens can be continuously performed. Grinding and fine grinding. The lens processing based on this method is performed by the rough grinding and fine grinding of the first surface by the cup-shaped grinding wheel and the abrasive grain plate mounted on the two-axis grinding machine, and then the lens blank is turned over, and the continuous operation is performed. 2 surface rough grinding and fine grinding, then the lens blank is conveyed to the polishing machine, the polishing surface is used to polish the first side and the second side, and then the lens blank is conveyed to the centering machine for peripheral processing, and then the finished The processed lens is transported to a washing machine for cleaning. According to the lens processing by the above method using the two-axis grinding machine, one or two processing apparatuses are reduced, and the lens conveyance between the apparatuses is also reduced by one or two times. Further, the chance of occurrence of the positioning error generated when the lens blank is mounted on the apparatus for transporting the target is also reduced, so that the accuracy and productivity of the mirror processing can be improved. Regarding the lens holder that holds the lens description during grinding, it is known to use a chuck structure that grips the outer circumference of the lens material and an adsorption structure that holds the lower surface of the vacuum suction lens material. In the latter configuration, it is necessary that the adsorbed lens material does not slip on the holder, but when the adsorption surface of the lens column is a surface that is only rough-ground, a vacuum leak will occur, and sufficient holding force cannot be obtained. Fast grinding is not possible. On the other hand,

In the mirror centering machine, (4) the upper and lower loading frames with annular edges are used to clamp and hold the lens blanks after polishing on both sides. [Patent Document 1] JP-A-2006-297520 SUMMARY OF THE INVENTION An object of the present invention is to provide a lens processing method and a grinding device that do not require a centering machine, thereby simplifying the rough grinding from the lens cleaning to the cleaning. The finishing of the polished lens is completed, and the type of equipment used is reduced to achieve productivity improvement in lens processing and reduction in equipment cost. In the lens processing including the processing method of the present invention, after the rough grinding and fine grinding of the 述1 φ of the lens description, the apparatus is switched to perform the rough grinding and fine grinding of the 帛2 surface and the outer circumference (m, then Performing the polishing of the first side and the second side 'The final cleaning of the finished polishing. Using two sets of lens processing in the lens processing including the processing method of the present invention - the shaft grinding machine, the polishing machine and the washing machine Lens processing from rough grinding to polished lens. No centering machine is used. First, the lens chain is mounted on the first two-axis grinding machine for rough grinding and fine grinding of the first φ, followed by lens blank It is conveyed to the 2nd twin-axis grinding machine, and the 面2 twin-axis grinding machine performs rough grinding, fine grinding and outer circumference of the second surface.] 5 of the double-axis grinding machine 2010 29797 Lens holder is the chuck structure The cage, the crucible cage is the cage of the adsorption structure. The lens of the card is the holder of the tray structure and the Gusaki is fully capable of withstanding the rough grinding of the first side. Therefore, the lens that is attracted to the holder in the second biaxial grinding machine It is sufficient to ensure the airtightness between the lens blank and the holder, and to receive sufficient blank holding force for rough grinding of the second surface. In the processing method of the present invention by the second double-axis grinding machine,参=: grinding and peripheral processing of the 2nd surface (fixing the first side of the lens chain 已经 has been finished grinding, flute in the waste "you" (four) grinding the 2nd axis grinding machine takes the completed == as the benchmark In order to keep the remaining material, the coarse grinding, fine grinding and peripheral processing of the second surface of the second state of the holding state are carried out, so that the centering of the rail material can be realized by machining. The rough grinding and fine grinding of the surface of the second surface: This sequence is carried out, but the outer circumference can be carried out at any stage. The general processing is performed after the second surface is finished. The outer circumference processing can be performed by the outer cylinder surface of the rough grinding cup wheel, but it is also possible The grinding wheel shaft is set to three axes. The grinding wheel dedicated to the outer peripheral machining is attached to the third grinding wheel shaft for peripheral processing. * The lens blank processed in the second double-axis grinding machine is conveyed to = light, ', Polishing the surface of the 仃帛i surface and the second surface 'finally using the cleaning machine to clear the lens that has been π processed. The second step of the above-described processing method includes a rotating workpiece shaft and a lens holder attached to the front end of the rotating workpiece shaft 1 so that the lens is polished by using the polishing of the aqueous processing liquid. The curvature of the spherical surface is located on the central axis of its rotation to adsorb and 'hold the spherical surface, and a plurality of rotating grinding wheel shafts parallel to each other are opposite to the front end 6 201029797, and a tool holder is mounted on the opposite end thereof; χ (4) The rotary grinding wheel shaft or the rotary machining 1 moves in the direction of the axial direction of the rotating grinding wheel shaft: the "swinging table" which rotates the grinding wheel shaft or rotates the workpiece shaft: the oscillation of the set rotation axis The rotation center axis and the axis of movement of the X moving table are orthogonal to each other, the axis swings the moving stage, which causes the front end and the swing center, p to approach and leave; and (4) the device 'which controls the Z moving table and the X moving A of

The swing position. It is possible to perform rough grinding and fine polishing of the lens by installing the grinding wheel for grinding in the other side of the tool holder in the moving position of the moving motion and the swinging table 4 in the tool holder. Grinding and peripheral grinding for the heart, without the need to switch the holding lens blank on the same device. The suction portion of the lens holder attached to the front end of the workpiece shaft 1 communicates with a through hole provided in the axial center of the workpiece shaft 1, and passes through the through hole and the rotary feed member attached to the lower end portion of the workpiece shaft 1, and The vacuum source connected to the rotary joint is supplied with a vacuum pressure for adsorbing the lens blank from the positive line to the lens holder. When the grinding wheel for fine grinding installed in the two-axis grinding machine uses a cup-shaped grinding wheel that is in circular contact with the spherical surface of the lens, the wear of the grinding wheel is large. Therefore, it is preferable to provide a correction unit that corrects the wear of the grinding wheel. The 胄 correction can be realized by registering a correction moving unit in the controller, the correction movement unit π is set as a constant of the (four) amount of the grinding wheel and v, and the angle formed by the rotating workpiece shaft and the rotating grinding wheel shaft is set to one. The x mobile station and the z mobile station are respectively corrected by (Δχ) and (Δζ) calculated by Δ) <=Mxtane, Δζ=Atx]/cose. In the present invention, when the first surface of the lens chain is ground, the lens 7 201029797 is protected: the pound is used to grind the second section by the force capable of withstanding the reaction force of the rough grinding process. In the case of the surface, the finished first surface is held by adsorption, and the lens is held by the force that can withstand the reaction force during the rough grinding of the second surface. According to the present invention, it is possible to perform the first lens blank in the same manner. Grinding and centering of the second side of the lens (4) can be performed by a single device using coarse grinding, fine grinding and peripheral processing on the second side of the cymbal. , : ^ 元 元 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精 精In the state of the outer circumference, it becomes a core processing. Gp 'The grinding surface of the second surface is maintained by the adsorption holder having the annular edge and the support surface processed into the same shape as the surface, so that the lens side and the holding are performed. There is no error in the shape of the surface on the side of the rack, and the surface has a small roughness. Therefore, it can prevent leakage of the vacuum pressure of the adsorption holder, obtain a firm holding force, and achieve high-precision centering processing in the grinding stage. (4) According to the present invention, when the lens is processed, the centering machine is not required, and the structure and even the operation of the cleaning machine for the lens to be processed can be simplified, and the equipment cost can be reduced. Further, the reduction in the processing efficiency of the shortening process can be achieved by reducing the amount of lens injection between the devices and the number of people who can change the tool. Further, in the second biaxial grinding machine, the lens chain is held on the basis of the surface on which the finish grinding is completed, and the second surface rough grinding, fine grinding, and centering processing can be performed without switching the grip. The peripheral processing is performed as a processing of the _ series, so that high-precision lens processing can be realized. Further, it is also possible to prevent a defective product from being generated due to a positioning failure occurring when the device for switching the lens is switched or even switched. 8 201029797 [Embodiment]

The first drawing is a view schematically showing an example of a processing step of a lens by the method of the present invention. In the first case, the first surface and the second surface are ground by the cup grinding wheel for fine grinding, and the outer surface is processed by the cup grinding wheel for rough grinding. In the figure, 1Ga denotes a second biaxial grinding machine, _ denotes a second biaxial grinding machine, 2 denotes a polishing machine, 3 denotes a washing machine, 4 denotes a lens blank, and 4a denotes a lens blank,牝 indicates that the second surface '4c of the lens blank indicates the outer circumference of the lens blank, 3a indicates a cup-shaped grinding wheel for rough grinding, 3b indicates a cup-shaped grinding wheel for fine grinding, and 12a indicates a card for the first, two-axis grinding machine 10a. A blank holder for a disc structure (hereinafter referred to as "chuck"), and 2b a blank holder for the adsorption structure of the second biaxial grinding machine 1〇b (hereinafter referred to as "adsorption holder"). Lens blank 4 First, the first surface 4a faces upward, and is mounted on the chuck 12a of the double-axis ❹m gamma, and performs the first s4a = . (p - (a)) and fine grinding (first (b)) Then, the first, =, ·! finely grounded traverse material is mounted on the adsorption holder 12b of the 2 biaxial grinding machine 10b with the 帛2 face up, and the second surface 4b: rough grinding (Fig. (c)) and fine grinding (Fig. (d)), and then, in the state in which the adsorption holder 12b is maintained in the state of the lens, the cylinder is faced with the cup-shaped grinding wheel 3a for rough grinding. Grinding of the outer peripheral side of the mirror plus H-type 'Using the front end of the cup-shaped grinding wheel 3a for rough grinding = grinding of the outer peripheral end surface (first figure (1)). Grinding of the outer peripheral side surface of the above lens r Λ, ^ ( In the figure, the result is the centering of the lens. The second biaxial grinding machine is used. The lens blank after processing is transferred to the throwing 9 201029797. The optical machine 20' performs the first surface by a conventionally known method. And the polishing of the second surface, the processing of the lens is completed. The finished lens is transported from the polishing machine 2 to the cleaning machine 30, and the processing liquid of the polishing machine 20 is washed away. In addition, the cleaning machine 30 is independent in the first figure. The apparatus 'but can also be attached to the polishing machine 20'. In this case, no delivery from the polishing machine 20 to the cleaning machine 3 is required. Among the various devices shown in the first figure, the polishing machine 20 and the cleaning machine 3〇 A conventionally known apparatus can be used. Patent Document 1 describes a two-axis grinding machine that performs fine grinding using an abrasive disc. In the first figure, a two-axis grinding machine that performs fine grinding using a cup-shaped grinding wheel is exemplified. Hereinafter, reference is made to the second diagram showing a side view thereof. An example of a two-axis grinding machine that uses a cup-shaped grinding wheel for grinding and fine grinding. In the second figure, 1 denotes a workpiece axis, and n denotes a motor for driving the workpiece shaft ' 12a, 12b denotes a workpiece shaft 1 a front end (upper end) lens holder, 13 denotes a lifting table direction moving table for supporting the workpiece axis 。. 23 denotes an oscillating table that swings around the swing center p, 21 denotes a guide provided on the oscillating table 23, and 22 denotes an edge The moving table (X-direction moving table) on which the guide 21 moves. The two grinding wheel shafts 25a, 25b are axially supported on the X moving table 22 in parallel with each other. The guide 21 is orthogonal to the two grinding wheel shafts 25a, 25b. Direction setting. As shown in the second figure, the lens holder 12a of the first biaxial grinding machine 1A has a retainer 8 having a chuck structure for gripping the claws 31 of the outer periphery 4c of the lens blank 4, as shown in Figs. 4 to 6 The lens holder 12|3 of the second biaxial grinding machine i〇b is a holder having an adsorption structure of the adsorption portions 32a and 201029797 32b and 32c of the first surface 4a on which the finish grinding is completed. In the adsorption holder shown in the fourth figure, the adsorption portion 32a is formed in the same shape as the first surface 4a on which the finish grinding is performed, and a material having a relatively low friction coefficient may be adhered to the adsorption portion 32a. Sheet cymbal 33. On the other hand, the structure of the adsorption holder 12b shown in FIG. 5 is such that the peripheral edge portion 34b of the adsorption portion 32b is processed into the same shape as the peripheral portion of the first surface 4a on which the finish grinding is completed, and the central portion is formed to be adsorbed. a shallow recess of the portion (vacuum reservoir) 32b. Further, the adsorption holder 12b shown in Fig. 6 has a structure that supports the annular edge 34c of the peripheral edge portion of the first surface 4a, and the inside of the annular edge serves as the adsorption portion 32c. The hole 35 at the center of the adsorption portion communicates with a through hole provided at the axial center of the workpiece shaft ', and communicates with a vacuum source through a rotary joint (not shown) attached to the lower end of the workpiece shaft. Regarding the bearing faces 32a, 34b of the adsorption holder 12b shown in the fourth and fifth figures, it is preferable to mount the end mill on the grinding wheel shaft 25b of the second twin-axis grinding machine to which the adsorption holder 12b is attached, and at the controller 5 The program for processing the bearing surface is registered for CNC machining. According to this method, it is possible to obtain 10 absorbing material holders i2b having bearing surfaces 32a, 34b which are in close contact with the first surface 4a of the honed fine grinding without gaps, and can be obtained to withstand strong grinding and high-speed grinding. Higher retention. Referring again to the second figure, a tool holder 29a and a coffee cup are provided at the shaft end of the lower end holder of the grinding wheel shafts 25a, 25b, and a cup grinding wheel for rough grinding is mounted on the _ individual eight holding wood 29a. 3a, a fine grinding cup wheel 3b is attached to the other tool holder 29b. The motors 26a and 26b for driving the grinding wheel shaft are connected to the respective grinding wheel shafts 25a and 25b. The cup-shaped grinding wheels 3a, 3b are wheels in which the surface of the lens material to be added I is brought into contact with the sand of the sand 201029797 along an arc centered on the central axis of rotation of the grinding wheel. The cup-shaped grinding wheel 3a for rough grinding is a cup-shaped grinding wheel having a grain size of 1 to 350 in the size of the grinding wheel. The cup-shaped grinding wheel 3b for fine grinding is a cup-shaped grinding wheel having a grain size of 1 500 to 2500. The machining allowance of the lens surface in the polishing after the finish grinding (the thickness in the optical axis direction of the lens surface which is cut off by the processing) is 1 〇 5 5 〇 μη

(micron). If the surface roughness of the finish and the curvature error of the lens exceed the range of the machining allowance during polishing, the processed lens becomes a defective product. Therefore, it is necessary to perform ultra-fine surface roughness processing by fine grinding, and it is necessary to use a fine wheel having a grain size of about 1500 to 2500. On the other hand, such a grinding wheel having a higher grain size (smaller grain size) is more likely to be worn than a grinding wheel having a lower grain size (about 1 to 35 angstroms). Although it differs depending on the material of the grinding wheel and the lens, the amount of wear in the processing of a lens reaches the level of 〇 5 μm. In the CG machining using the cup-shaped grinding wheel, if the grinding wheel is worn, the radius of curvature of the processed lens surface increases. Therefore, the relative positional relationship between the grinding wheel and the lens material must be corrected so that the radius of the curvature of the lens machined by the wear of the grinding wheel is within the permissible precision. ’

In the apparatus of the Chinese X 隹霄 embodiment, in order to perform the correction, Table 54 indicating the amount of wear At of the sand direction of the cup sand _ 3 per predetermined number of processing is registered in the control | And the calculation formula of the correction amount of the mobile station 22 and the lifting platform 13 using the Δί table,

Δχ = AtxtanB Δ Z = Atx 1 /c〇s0. Table 54 of Table 7 (4) Loss Δί is the number of processed lenses 5, 10, 15... after 3 mm of the grinding wheel type 3b of the new 12 201029797, for example, in accordance with 3 (units: micron) ), 2 7 , 2 5 ... In this way, the amount of wear m in the direction of the grinding wheel axis of the grinding wheel generated during the processing of the five lenses of the lead is measured. Returning to the second figure, the workpiece shaft 1 is pivotally supported on a lifting platform 13 guided by the frame 2, and the bracket 14 integrated with the lifting table is screwed into the Z-axis driven by the Z-axis servo motor 17. Give the screw to the rod 18. The oscillating table 23 is driven by the B-axis feed motor 37 to swing. The X moving table 22 is screwed onto the feed screw 28. The feed screw 28 is driven by the X-axis servo motor 27 mounted on the oscillating table 23 to rotate the motor to indicate the numerical control device for controlling these servo motors. 52 and 53 denote servo amplifiers, and 19 denotes a current clamp of the Z-axis servo motor 17. Next, a process of grinding the lens by the apparatus shown in Fig. 2 will be described. First, the position of the grinding wheel shaft 25a on which the rough grinding cup type grinding wheel 3a is attached is set at the moving origin of the swaying table 22 by the position of the swing center P of the oscillating table 23, so that the oscillating table 23 is inclined to correspond to the spherical surface to be ground. The angle θ of the curvature θ' sets the position of the X moving stage 22 to the position where the contact circle of the rough grinding cup type grinding wheel 3a and the spherical surface of the lens passes through the optical axis of the lens, and grinds the workpiece shaft 1 corresponding to the grinding amount. The completion position is set at the origin of the z-axis. Further, the lens blank 4 is attached to the lens holder 12, and the rough grinding cup type grinding wheel 3a formed by the rotation of the workpiece shaft 1 and the rough grinding cup type grinding wheel 3a formed by the rotation of the grinding wheel shaft 25a are formed. Rotation, the spherical surface of the lens culture material 4 held by the lens holder 12 is developed. Next, the position of the grinding wheel shaft 25a through the swing center p of the oscillating table 23 is set at the moving origin of the X moving table 22, and the oscillating table 23 is tilted to an angle of 13 201029797 corresponding to the curvature of the spherical surface of the lens to be ground, 把 X The position of the moving table 22 is set at a position where the contact circle of the cup-shaped grinding wheel 3b and the spherical surface of the lens passes through the optical axis of the lens (Q1 in the eighth figure), and the grinding element position of the workpiece shaft 1 corresponding to the grinding amount is set. The origin of the Z axis. Further, the rotation of the cup-shaped grinding wheel 3b formed by the rotation of the workpiece shaft 1 and the rotation of the cup-shaped grinding wheel 3b formed by the rotation of the grinding wheel shaft 25a perform the rough-grinding lens blank 4 held by the lens holder 12. fine grinding. When the cup-shaped grinding wheel 3b wears the amount of wear At due to the grinding of the lens, the contact circle of the cup-shaped grinding wheel 3b with the spherical surface of the lens deviates from the position passing through the optical axis of the lens (Q2 in the eighth figure). When the grinding cup type grinding wheel 3b is replaced with a new grinding wheel, the counter for counting correction timing is reset, and each time the number of processing of the lens based on the above method reaches 5, 1, 〇, 15..., the reading is performed with reference to the registered table. At, the X moving table 22 and the lifting table 13 at the time of fine grinding are moved by Αχ and az obtained by the above formula. By this correcting action, as shown in FIG. 8 'corrects the offset Δχ of the contact circle of the lens blank 4 and the cup-shaped grinding wheel 3b due to the wear of the cup-shaped grinding wheel Δί in the X direction, and the shift in the Z direction Δζ, the contact circle of the worn cup-shaped grinding wheel 3b and the spherical surface of the lens is returned to the position passing through the optical axis of the lens (Q3 in the eighth figure), and the error of the curvature of the lens surface and the error of the thickness of the lens are obtained by the wear. Correction. Here, the advantages of the method of performing fine grinding using a cup type grinding wheel will be described. In the conventional lens processing, fine grinding is performed using an abrasive disc. However, the abrasive disc is a structure in which a plurality of smaller grinding wheel plates are adhered to a curved surface that matches the curvature of the spherical surface of the lens to be processed (a concave curved surface when the convex lens is processed), so the curvature of the surface of the lens to be processed each time. When changing, it must be replaced with an abrasive disc abrasive disc corresponding to the curvature of 14 201029797. It is necessary to prepare a specific one for each lens to be processed. In the π machining (spherical surface forming process) using the cup type grinding wheel, by changing the angle θ of the rotation center axis of the cup type grinding wheel with respect to the optical axis of the lens, _ The curvature of the lens surface to be processed, so that it is possible to perform processing of various lens surfaces having different curvatures using a cup type grinding wheel.

Thus, in the lens processing method of the present invention, a method of performing fine grinding using a cup type grinding wheel is preferred. However, the method of the present invention can also be employed in lens processing for fine grinding using an abrasive disc. In this case, for example, a spherical grinding device proposed in the patent document can be used as the second biaxial grinding 0a and 10b. Further, in the above-described display, the outer peripheral processing of the lens blank to be centered is performed by the rough grinding cup type grinding wheel. However, a three-axis grinding machine having three grinding wheel shafts may be used, and the three grinding wheel shafts may be respectively used. It is also a good method to install a cup type grinding wheel for rough grinding, a cup type grinding wheel for fine grinding, and a grinding wheel for peripheral processing, and to perform peripheral processing using a dedicated grinding wheel. Hereinafter, the cup described in the above embodiment will be specifically described. The grinding wheel corrects the wear of the grinding wheel when the lens blank is refined. In the conventional rough grinding, the error correction based on the wear of the cup type grinding wheel for rough grinding was performed as follows. That is, the processed lens is extracted periodically or after every predetermined number of lens processings, as shown in the ninth figure, the ring-shaped stage 61 and the contact 62, which are known by the diameter L of the measuring edge, are clamped to be thick. The ground lens blank 4 is measured by a micrometer (the height in the optical axis direction, the height of the surface and the back surface is shown), and the deviation of the measured value from the value of the proof gauge (reference lens) is input to the grinding device. Controller. The controller calculates the correction amount in accordance with a predetermined arithmetic expression of 15 201029797 in advance, and corrects the angle θ of the grinding wheel shaft with respect to the workpiece axis to cancel the error of the radius of curvature R caused by the wear of the grinding wheel. However, the following problems will occur when the correction method is applied to the wear of the cup grinding wheel for fine grinding. First, the wear of the fine grinding wheel is much larger than that of the grinding wheel of the grinding wheel. Therefore, in order to perform the calibration, the sampling of the lens is frequently performed, resulting in an operator's heavy work load. The second 'when the grinding wheel wears a large amount of damage, the error of the center thickness of the lens must also be corrected, but the above conventional correction is only the correction of the curvature radius of the workpiece'. Make other corrections. In the second correction of the angle 0 of the grinding wheel axis with respect to the workpiece axis, the shape of the grinding wheel of the grinding wheel does not match the curved surface shape of the lens surface at the end of the machining. Therefore, if the angle θ of the grinding wheel axis is adjusted as usual to correct the lens, the lens is corrected. The contact point between the surface and the grinding wheel is offset (the line of contact between the grinding wheel and the lens surface is offset from the arc centered on the center of rotation of the grinding wheel), and the surface of the lens after machining does not become a spherical surface. These problems are caused by the fact that the wear amount of the cup grinding wheel for refining is far greater than the wear amount of the cup grinding wheel for rough grinding. The above problems can be solved as described below. That is, according to the type of the grinding wheel and the lens to be processed, the relationship between the machining amount (the number of machining or the machining time) and the wear amount of the grinding wheel is measured in advance by the test processing, and the relationship between the two or the relationship between the two is expressed. The table is pre-registered in the controller 5. Further, after each predetermined number or every predetermined time of lens processing, the wear amount of the grinding wheel to be predicted (wearing dimension of the grinding wheel axis direction) At is estimated by referring to the arithmetic expression or table. Then, the X moving table 22 is moved by Δχ obtained by the magic xtanG operation, and the moving amount Δζ of the lifting table is moved by Az calculated by Δ~16 201029797 Δtx1/c〇S0, thereby estimating the amount of wear. At performs correction. The correction direction is as shown in the first figure, which is a direction in which the contact circle of the worn grinding wheel and the spherical surface of the lens passes through the center W of the lens ground by the worn grinding wheel. By adopting the above-described scheme, the wear can be frequently performed frequently due to the large wear. The refining requires correction for the wear of the cup-shaped grinding wheel without disturbing the operator's manual correction' and also avoids the phenomenon that the shape of the processed spherical surface is unstable due to the correcting operation. Further, according to the above correction, both the error of the curvature of the lens surface caused by the wear of the grinding wheel and the error of the lens thickness of the center portion can be simultaneously corrected, and the cup type grinding wheel having a large wear can be used to perform the machining precision requirement. fine grinding. That is, in the refining of the lens blank of the above embodiment, the rough-polished lens blank 4 is held at the front end of the workpiece shaft 1 controlled by the numerical control (NC) at the lifting position, and is utilized on the yoke provided on the oscillating table 23. A rotating® grinding wheel on one of the grinding wheel shafts 25a, 25b axially supported by the moving table 22 and opposite to the front end of the workpiece axis j (the grinding wheel shaft 25b in the above embodiment), the lens for the rough grinding The blank 4 is subjected to fine grinding. Wherein, the swinging table 23 is digitally controlled around the swinging angle of the pivot center p passing through the axis of the workpiece axis, and the moving position of the X moving table 22 in the direction orthogonal to the axes of the grinding wheel shafts 25a, 25b is numerically controlled (NC) )control. In the above fine grinding, the grinding wheel is a grinding wheel in circular contact with the surface of the lens to be processed, and the cup type grinding wheel 3b having a grain size of 1500 to 2500 is used, so that the grinding wheel shaft is inclined to be corresponding to be ground. The angle of the curvature of the spherical surface of the lens is set such that the position of the parent moving table 22 is set at a position where the contact circle of the grinding wheel 3b and the spherical surface of the lens passes through the center of the light of the lens, and the rotation of the workpiece shaft and the sand 17

201029797 Rotation of the axle 25b to finish the rough grinding of the lens blank 4. In the above-described lens refining method, 'the arithmetic expression indicating the relationship between the processing amount of the lens and the wear amount of the grinding wheel or the table indicating the relationship is registered in the numerical control device, at the time of continuous processing of the lens, every predetermined After the amount is added, the amount of wear of the grinding wheel at this time is obtained by referring to the calculation formula or the table Δ, and the heights of the X moving table 22 and the workpiece axis are respectively moved by Δζ calculated by the knitting _, heart = _/C〇se, The amount of wear thus obtained is corrected so that the next lens is processed. BRIEF DESCRIPTION OF THE DRAWINGS The first figure 示意图 shows a schematic view of the processing method of the present invention. The first figure is a side view showing an example of the grinding apparatus of the present invention. The second drawing is a cross-sectional side view showing an example of a lens holder for holding the outer periphery of the lens blank. The fourth circle is a cross-sectional side view showing a first example of a lens holder that adsorbs and holds the spherical surface of the lens blank. Fig. 5 is a cross-sectional side view showing a second example of the lens holder that adsorbs and holds the spherical surface of the lens blank. Fig. 6 is a cross-sectional side view showing a third example of the lens holder that adsorbs and holds the spherical surface of the lens blank. Fig. 7 is a view showing an example of a table showing the relationship between the number of grindings and the amount of wear of the grinding wheel. The eighth diagram is an explanatory diagram for explaining the principle of the wear correction of the grinding wheel. The ninth diagram is a schematic side view showing an example of the method of measuring the spherical surface of the lens. 18 201029797 [Description of main component symbols] 1 The workpiece shaft 2 frame 3a is roughened by a cup shape Grinding wheel 4 lens blank 4b second surface 3b refining cup grinding wheel 4a first surface 4c outer circumference 5 controller 10a first biaxial grinding machine 10b second biaxial grinding machine 11 motor 12 lens holder 12a chuck structure Lens holder

12 b adsorption structure lens holder 13 lifting table (Z direction moving table) 14 bracket 17 Z axis servo motor 1 8 Z axis feeding screw 1 9 current controller 20 polishing machine 22 X moving table 21 guide X direction Mobile station)

23 oscillating table 25b grinding wheel shaft 26b motor 28 feeding screw 29b tool holder 31 claw 32b suction portion 33 sheet gasket 34c annular edge 37 B-axis servo motor 52 servo amplifier 25a coarse grinding wheel shaft 26a Motor 27 X-axis servo motor 29a Tool holder 30 Washer 32a Adsorption unit 32c Adsorption unit 34b Peripheral part 3 5 Hole 51 Servo amplifier 53 Servo amplifier 19 201029797 54 Table 62 contacts

Claims (1)

201029797 VII. Patent application scope: 1. The processing method of a kind of lens, which is characterized by the penetration of the grinding after the grinding (4) (4) the first 彳 把, · 》 吸 吸 吸 吸 吸 吸 吸 吸 吸 吸 吸 吸 吸 吸 吸 吸The strong energy πτ Α of the adsorption holding 捭 is maintained in a state where the adsorption is maintained, and the rough grinding of the 帛2 surface of the permeable material is performed, and the outer periphery of the lens is performed by a grinding wheel for rough grinding. "The second side of the rough grinding 2. The method for processing a lens according to the above-mentioned patent application, wherein the 'spherical grinding machine' has a 帛1 rotating grinding wheel shaft on which a rough grinding cup-shaped grinding wheel is mounted, and is installed for performing a second rotating grinding wheel shaft of the fine grinding wheel and a rotating workpiece shaft on which the adsorption holder is mounted, the adsorption holder holding a center of curvature of the finely ground surface of the grinding workpiece on the rotating workpiece shaft The center of rotation is on the axis. 3. The method of processing a lens according to claim 2, characterized in that the second surface is ground by a cup-shaped grinding wheel in circular contact with the surface of the lens blank to be processed, the cup The grinding wheel is a grinding wheel with a particle size of 1 500 to 2500. 4. The method of processing a lens according to claim 2, wherein the peripheral processing of the lens blank is performed by the grinding wheel for rough grinding. 5. A grinding device for a lens, comprising: a rotating workpiece shaft; a lens holder mounted on a front end of the rotating workpiece shaft such that a center of curvature of the spherical surface of the lens is located on a central axis of rotation thereof to adsorb and hold the spherical surface; 21 201029797 a plurality of rotating grinding wheel shafts parallel to each other, a tool holder mounted on an opposite end thereof opposite to the front end; an X moving table moving the rotating grinding wheel shaft or the rotating workpiece shaft in a direction crossing the rotating grinding wheel shaft An oscillating table that swings the rotating grinding wheel shaft or the rotating workpiece shaft about a swinging central axis that passes through a swing center P set on the rotation center axis, and moves with the rotation center axis and the X a moving direction of the stage is orthogonal; a z moving station that brings the front end and the swing center p close to or away from; and a controller that controls a moving position of the Z moving station and the X moving station and the swing The swing position of the table is installed by installing a grinding wheel for grinding on one of the tool holders and a grinding wheel for fine grinding on the other side. Rough grinding, fine grinding and grinding of the outer periphery for centering of the spherical lens blank. 6. The grinding device for a lens according to claim 5, wherein: the controller has a correction moving unit that sets a constant given as a wear amount of the grinding wheel to At, The angle between the rotating workpiece axis and the rotating grinding wheel axis is θ, and the X moving table and the Z moving table are respectively moved and corrected by Δχ and Δζ calculated by AxsAlxtane and Δζ=Atx1/cose. Eight, schema · (such as the next page) 22