JP2006334701A - Spectacle lens machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce axial deviation at the time of machining and to perform machining with reduced axial deviation also on a water repellent lens without using an adhesive sheet. <P>SOLUTION: A spectacle lens machining device has a shaft distance fluctuation means for fluctuating a shaft distance between a lens rotary shaft to be rotated by a rotating means by holding a spectacle lens and a machining tool rotary shaft to machine a peripheral edge of the lens. The spectacle lens machining device machines the peripheral edge of the lens by controlling an operation of the shaft distance fluctuation means based on machining data obtained by lens shape data, etc. The spectacle lens machining device is provided with a means 11 for selecting whether or not the machining for making cutting amount substantially constant is performed and a means 500 for measuring lens external shape data before the machining for the lens rotary shaft. When the machining for making the cutting amount substantially constant is selected, the machining is performed by controlling the operation of the shaft distance fluctuation means so that the lens rotary shaft may be rotated at fixed speed and the cutting amount during one rotation of the lens may be made substantially constant. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a spectacle lens processing apparatus that processes a peripheral edge of a spectacle lens so as to match a spectacle frame shape.

An eyeglass lens processing apparatus is known that holds a spectacle lens by a lens rotation shaft and processes the lens periphery with a processing tool such as a grindstone while rotating the lens (for example, Patent Document 1). When processing the lens periphery, fix the cup, which is a jig for holding the lens, to the front surface of the lens, hold it on one lens rotation shaft, and hold the lens holding on the tip of the other lens rotation shaft. Thus, the lens is clamped. The cup is fixed using suction or double-sided adhesive tape (leap tape).
JP 2004-255561 A

  By the way, when processing the peripheral edge of the lens with a processing tool that rotates at high speed, if an excessive load exceeding the force to hold the lens is applied to the lens, a rotational displacement occurs between the cup and the lens, so-called axial misalignment. May occur. In particular, there is a water-repellent lens that has been coated with a water-repellent substance that is difficult for water and oil to adhere to recently, and this water-repellent lens is slippery even when a double-sided adhesive tape is used to fix the cup. Therefore, the possibility of shaft misalignment increases. In the apparatus of Patent Document 1 described above, it is possible to reduce to some extent the possibility of axial misalignment during rough machining by controlling the processing pressure to be weak, but even when using a water repellent lens, the misalignment is suppressed. Processing is desired.

  In the processing of the water-repellent lens, a film-like pressure-sensitive adhesive sheet is further attached to the lens refracting surface to make it difficult to slip. The effect of the pressure-sensitive adhesive sheet is enhanced by being attached to the lens pressing side (lens rear surface side). However, the operation of attaching the pressure-sensitive adhesive sheet is not only laborious but also costly. In addition, if wrinkles are formed when the protective seal is applied, there is a problem that a defective finish occurs at that portion.

  The present invention provides an eyeglass lens processing apparatus that can reduce the axial deviation during processing and can perform processing with reduced axial deviation without using an adhesive sheet even in the case of a water-repellent lens. This is a technical issue.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) It has an inter-axis distance changing means for changing the inter-axis distance between the lens rotating shaft that holds the spectacle lens and is rotated by the rotating means and the processing tool rotating shaft that processes the peripheral edge of the lens. In a spectacle lens processing apparatus that processes the lens periphery by controlling the operation of the inter-axis distance varying means based on the processing data obtained, the amount of cut during one rotation of the lens by rotating the lens rotation shaft at a constant speed It is characterized by comprising control means for controlling the operation of the inter-axis distance varying means so that is substantially constant.
(2) In the eyeglass lens processing apparatus according to (1), the spectacle lens processing apparatus includes means for measuring or inputting lens outer shape data before processing with respect to the lens rotation axis, and the control means makes the cutting amount substantially constant based on the lens outer shape data. The operation of the inter-axis distance changing means is controlled.
(3) The eyeglass lens processing apparatus according to (1) or (2) includes a selection unit that selects whether or not to perform processing for making the cutting amount substantially constant, and the control unit does not make the cutting amount substantially constant. When processing is selected, at least one of the rotating unit and the inter-axis distance varying unit is controlled to adjust the processing pressure by the processing tool and perform lens peripheral processing.
(4) The spectacle lens processing apparatus according to (1) includes a lens outer shape measuring unit that measures lens outer shape data before processing with respect to the lens rotation axis, and a selection unit that selects whether or not to perform processing with a substantially constant cut amount. The control means operates to obtain lens outer shape data by operating the lens outer shape measuring means before roughing when machining with a substantially constant cutting amount is selected, and based on the acquired lens outer shape data. When the machining of the lens peripheral edge processing is performed by controlling the operation of the inter-axis distance variation means so that the cutting amount is substantially constant, and the processing that does not make the cutting amount substantially constant is selected, The lens periphery processing is performed by controlling at least one of the distance changing means and adjusting the processing pressure by the processing tool.
(5) In the eyeglass lens processing apparatus according to any one of (1) to (4), at least one of edge thickness detecting means for detecting the edge thickness of the lens periphery before rough processing and material input means for inputting the lens material is provided. And the control means changes the cut amount based on at least one of edge thickness and lens material.
(6) Edge position measurement in the spectacle lens processing apparatus according to any one of (1) to (4), wherein a measuring element is brought into contact with the front and rear surfaces of the lens, and at least two edge positions are measured at different distances in the lens rotation angle. And edge thickness calculating means for obtaining the edge thickness of the roughened portion based on the measurement result of the edge position measuring means, and the control means is configured to rotate the lens one turn based on the edge thickness of the roughened portion. The cut amount is changed.

  According to the present invention, it is possible to further reduce the axial deviation during processing. In addition, it is possible to reduce the occurrence of axial misalignment during processing of the water-repellent lens without using an adhesive sheet.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a processing unit of a spectacle lens processing apparatus. On the main base 1, a sub-base 2 including a lens chuck upper portion 100 and lens grinding portions 300R and 300L is fixed. A lens shape measuring unit 500 is housed in the back side of the center of the sub base 2.

  A fixed block 101 constituting the lens chuck upper part 100 is fixed at the center of the sub-base 2, and a motor 103 for moving the lens rotating shaft holder 120 up and down is attached to the upper part. The motor 103 rotates a feed screw extending up and down, and this rotation guides a guide rail provided between the fixed block 101 and the lens rotation shaft holder 120 moves up and down. A pulse motor 130 that rotates the lens rotation shaft 121 is fixed to the upper portion of the lens rotation shaft holder 120. A lens presser 124 is attached to the lower end of the lens rotation shaft 121 (see FIG. 2). The lens rotation shaft 152 constituting the lens chuck lower portion 150 is rotatably held by a holder 151 fixed to the main base 1, and the rotation is transmitted by a pulse motor 156. A cup receiver 159 for attaching a cup fixed to the lens to be processed is attached to the upper end of the lens rotation shaft 152 (see FIG. 2).

  The lens grinding parts 300R and 300L are arranged symmetrically. A housing 305R that holds the processing tool rotating shaft 304R rotatably inside is attached to the front portion of the shaft support base 301R of the lens grinding portion 300R. The processing tool rotation shaft 304R is rotated by a motor 310R fixed to the upper portion of the shaft support base 301R via a rotation transmission mechanism such as a gear disposed inside the shaft support base 301R. The same applies to the lens grinding part 300L, and a housing 305L that holds the processing tool rotating shaft 304L rotatably inside is attached to the front part of the shaft support base 301L of the lens grinding part 300L. The processing tool rotating shaft 304L is rotated by a motor 310L fixed to the upper portion of the shaft support base 301L.

  As shown in FIG. 2, a rough grindstone 30 and a finishing grindstone 31 having a bevel groove are attached to the rotating shaft 304L of the lens grinding section 300L. Further, a chamfering grindstone 32 for processing the front surface of the lens having a conical surface is attached to the upper end surface of the finishing grindstone 31, and a chamfering grindstone 33 for processing the rear surface of the lens is coaxially attached to the lower end surface of the rough grindstone 30. The rotating shaft 304R of the lens grinding unit 300R includes a roughing cutter 36 for roughing, a mirror-finishing grindstone 37 having a bevel groove, a chamfering grindstone 34 for lens front mirroring having a conical surface, and a lens rear surface mirroring. A chamfering grindstone 35 is attached coaxially. The roughing cutter 36 has a configuration in which a six-blade diamond cutter having a groove capable of forming flattening and beveling is arranged facing one direction, and the lens periphery can be roughly processed by high-speed rotation.

  The lens grinding portions 300R and 300L can move in the vertical direction and the horizontal direction with respect to the sub-base 2, and the moving mechanism is as follows. The lens grinding unit 300R is fixed to the left and right slide base 210R, and the left and right slide base 210R is movable to the left and right along two guide rails 211R fixed to the upper and lower slide base 201R. On the other hand, the vertical slide base 201R can move up and down along two guide rails 202R fixed to the front surface of the sub base 2. A nut block 206R is fixed to the vertical slide base 201R. A pulse motor 204R is fixed to the upper right portion of the sub-base 2. By rotating the ball screw 205R coupled to the rotation shaft of the pulse motor 204R, the vertical slide base 201R is moved up and down together with the nut block 206R. The left / right moving mechanism of the left / right slide base 210R is basically the same as the up / down moving mechanism. A nut block 215R is fixed under the left and right slide base 210R. A pulse motor 214R is fixed to the lower right portion of the vertical slide base 201R. When the ball screw coupled to the rotation shaft of the pulse motor 214R is rotated, the left and right slide base 210R is moved left and right together with the nut block 215R. In addition, an encoder 217R capable of detecting the rotation state of the rotation shaft is attached to the motor 214R. The moving position of the left and right slide base 210R, that is, the moving position of the rotating shaft 304R of the lens grinding unit 300R is detected by the encoder 217R.

  The moving mechanism of the lens grinding unit 300L is the left and right moving mechanism and the left / right moving mechanism on the lens grinding unit 300R side, and description of each component is omitted. In the following description, “R” at the end of the reference numeral attached to each component of the moving mechanism on the lens grinding unit 300L side is replaced with “L” for each element of the vertical movement mechanism and the left / right movement mechanism of the lens grinding unit 300L. To do. For example, the vertical slide base 201L on the lens grinding section 300L side is moved up and down by a motor 204L, and the left and right slide base 210L is moved by a motor 214L fixed to the lower left portion of the vertical slide base 201L. Further, the moving position of the rotating shaft 304L of the lens grinding unit 300L is detected by the encoder 217L provided in the motor 214L.

  FIG. 3 is a schematic configuration diagram of a lens shape measurement unit 500 that detects the edge position of the lens LE. The measurement unit 500 includes a first probe 503 attached to the tip of the first arm 501 and a second probe 507 attached to the tip of the second measurement arm 505. The first probe 503 contacts the front refractive surface of the lens LE, and the second probe 507 contacts the rear refractive surface of the lens LE. The first arm support base 502 to which the first arm 501 is fixed and the second arm support base 506 to which the second measurement arm 505 is fixed are vertically moved along the rail 510 supported in the vertical direction of the slide base 512. It can be moved.

  A tension spring 509 is stretched between the first arm 501 and the second measurement arm 505, and is always urged in a direction in which the interval between the first measurement element 503 and the second measurement element 507 is reduced. A measurement arm moving motor 515 is fixed below the slide base 512, and a first feed screw 517 extending vertically is connected to the rotation shaft of the motor 515. The feed screw 517 meshes with a female screw portion formed on the first moving block 518 that can move along the rail 510. The first moving block 518 is moved up and down by the rotation of the feed screw 517. A gear 519 is fixed to the feed screw 517, and the gear 517 meshes with a gear 523 fixed to a second feed screw 521 extending vertically. When the feed screw 517 is rotated by the motor 515, the second feed screw 521 is rotated counterclockwise from the feed screw 517 via the gear 517 and the gear 523. The feed screw 521 meshes with a female screw portion formed on a second moving block 522 movable along the rail 510, and the second moving block 522 is moved up and down by the rotation of the feed screw 521. For example, when the motor 515 is rotated forward, the first moving block 518 moves downward to push down the first arm support base 502, and the second moving block 522 moves upward to raise the second arm support base 506. Push up. Thereby, the space | interval of the 1st arm 501 and the 2nd measurement arm 505 spreads. On the other hand, when the motor 515 is rotated in the reverse direction, the first moving block 518 and the second moving block 522 move in the direction in which the distance between the first moving block 518 and the second moving block 522 decreases, and thereby the first arm 501 and the second measuring arm 505 pulled by the tension spring 509. Are simultaneously moved in the direction of narrowing the interval.

  A rack 525 is fixed behind the first arm support base 502, and the movement of the rack 525 is detected by a first detector 527 such as an encoder fixed to the slide base 512. A rack 531 is also fixed behind the second arm support base 506, and the movement position of the rack 531 is detected by the second detector 533. That is, the first detector 527 detects the front edge position of the lens LE, and the second detector 533 detects the rear edge position of the lens LE. Reference numeral 535 denotes a spring that cancels the overload of the first measurement arm 501. The second measuring arm 505 also cancels overload by a spring (not shown).

  The slide base 512 is suspended and held by a rail 541 fixed below the fixed base 540 via a block 543 so as to be movable in the front-rear direction (left-right direction in FIG. 3). A pulse motor 545 is fixed to the fixed base 540, and a feed screw 547 is connected to the rotating shaft thereof. A female screw that meshes with the feed screw 547 is formed in the block 543, and the slide base 512 is moved in the front-rear direction (the left-right direction in FIG. 3) via the block 543 by the rotation of the feed screw 547.

  At the time of measuring the refractive surface shape of the lens LE, the slide base 512 is extended forward from the retracted position, and the measuring elements 503 and 507 are moved to the measuring position based on the target lens shape data. Thereafter, the measuring elements 503 and 507 are brought into contact with the refractive surface by driving the motor 515. In this state, the lens LE is rotated and the slide base 512 is moved back and forth based on the moving radius information of the target lens shape. The vertical movement position of the probe 503 at this time is detected by the first detector 527, and the lens is moved. The edge position of the front refractive surface is obtained. At the same time, the vertical movement position of the probe 507 is detected by the second detector 533, and the edge position of the lens rear-side refractive surface is obtained.

  FIG. 4 is a block diagram of the control system of the apparatus. Reference numeral 600 denotes a control unit that controls the entire apparatus and performs machining operations. Connected to the control unit 600 are a display unit 10 composed of a color liquid crystal display, an input unit 11 having various operation switches, a lens shape measurement unit 500, a spectacle frame measurement device 650, and encoders 217L and 217R for moving position detection. ing. Motors 204L and 214R that move the lens grinding unit 300L are connected to the control unit 600 via drivers 204aL and 214aL, respectively, and motors 204R and 214R that move the lens grinding unit 300R are controlled via drivers 204aR and 214aR, respectively. Connected to the unit 600. A data memory 603 stores input data, measurement data, and the like.

  Next, the processing operation of this apparatus will be described (see the flowchart in FIG. 11). Prior to processing, a cup, which is a fixing jig, is fixed to the lens LE using a well-known shaft hitter. FIG. 5 is a diagram for explaining blocking of the cup 50 to the lens LE before processing. In FIG. 5A, SF is a lens shape arranged on the lens LE, OC is the optical center of the lens LE, and FC is the geometric center of the lens shape SF. The layout of the target lens shape SF with respect to the lens LE depends on the wearer's PD (distance between pupils), FPD (distance between the centers of the left and right lens frames), and the height of the optical center OC relative to the geometric center FC. It depends on the data. By determining these values in advance, the relative relationship between the geometric center FC and the optical center OC is determined, and the target lens shape SF is laid out with respect to the lens LE. When the cup 50 is blocked on the front surface of the lens LE, there are an optical center mode in which the optical center OC is fixed as a reference and a frame center mode in which the lens center geometric center FC is fixed as a reference. In the frame center mode, first, after determining the layout of the target lens shape SF with respect to the lens LE, the cup 50 is fixed via a double-sided adhesive tape (leap tape) 51. Hereinafter, the case of the frame center mode will be described.

  The operator inputs the eyeglass frame lens shape data SF (Rn, θn) (n = 1, 2, 3,..., N) measured by the eyeglass frame shape measuring device 650 using the switch of the switch unit 11. To do. Also, layout data such as PD, FPD, and optical center height are input. In the case of the optical center mode, the target lens shape data SF (Rn, θn) is converted into radius vector data based on the lens rotation center by the input of the layout data, but in the case of the frame center mode, the lens rotation center is used as a reference. The moving radius data is used as the target lens shape data SF. Also, processing conditions such as beveling, chamfering, and lens material are input. Furthermore, whether to use a soft machining mode (a machining mode in which the amount of cut from the lens periphery is substantially constant) or a normal machining mode (a machining mode that detects the machining pressure and changes the machining pressure). Is selected by a switch arranged in the switch unit 11. This selection may be made based on whether the lens surface is a slippery lens or whether a water repellent coating is applied.

  When necessary data and processing conditions can be input, the base of the cup 50 is mounted on the cup receiver 159 of the lens rotation shaft 152, and the chuck switch of the switch unit 11 is pressed to chuck the lens LE with the lens rotation shaft 121. . Thereafter, the processing start switch is pressed to operate the apparatus.

  A case where the soft machining mode is selected will be described. First, the outer shape of the lens LE to the periphery of the lens rotation axis (121, 152) is measured by the processing start switch. FIG. 6 is a diagram for explaining the measurement of the outer periphery of the lens LE. In the present embodiment, the coarse grindstone 30 is used for measuring the lens peripheral contour, and the left / right moving mechanism of the lens grinding unit 300L that changes the distance between the rotation shaft 304L and the lens rotation shafts 121 and 152 is used. The controller 600 controls the driving of the motor 214L and moves the left and right slide bases 210L to the lens rotation axis side, as shown in FIG. The coarse grindstone 30 is pressed against the periphery of the LE. In measuring the peripheral edge shape of the lens LE, the control unit 600 presses the rough grindstone 30 against the lens LE with a pressure lower than that during rough machining. The pressing force (working pressure) of the grindstone 30 can be adjusted by controlling the current since the current driving the motor 214L is detected by the driver 214aL. The controller 600 rotates the lens LE by driving the motors 130 and 156 to rotate the lens rotation shafts 121 and 152 in a state where the rough grinding stone 30 is brought into contact with the periphery of the lens LE with a weak pressure. At this time, since the rotation of the rough grindstone 30 is stopped, the lens periphery is not ground. The controller 600 determines the distance Ln between the lens rotation shaft and the rotation shaft 304L of the encoder 217L for each rotation angle Θn (n = 1, 2, 3,..., N) of the lens LE driven by the motors 130 and 156. Read from the value. Since the radius TR of the rough grindstone 30 is known, by subtracting the radius TR from the inter-axis distance Ln, the distance ERn from the lens rotation center about the lens rotation axis to the periphery of the lens LE is set to the rotation angle Θn (n = 1, 2, 3,..., N). Distance data (ERn, Θn) (n = 1, 2, 3,..., N) from the lens rotation center to the lens LE periphery is stored in the memory 603.

  Note that the measurement mechanism for measuring the outer shape from the lens rotation center to the periphery of the lens LE is not limited to the above. For example, a method of pressing the side surface of the measuring element 503 or 507 of the lens shape measuring unit 500 against the periphery of the lens may be used. In this case, it is only necessary to press the side surface of the probe 503 against the periphery of the lens with a weak pressure by driving the motor 545 that is the back-and-forth moving means, and detect the movement position of the probe 503 using an encoder or the like.

  Further, the lens outer shape data may not be obtained using the lens shape measuring unit 500 on the apparatus main body side, but may be configured such that data measured by another apparatus is input by communication or the like. Furthermore, when the diameter of the fabric lens before rough processing is known in advance, the value and layout data are input at the input unit 11 to calculate and obtain lens outer shape data with respect to the lens rotation center. It is possible (this is also included in the input of lens outline data).

  After measuring the outer shape of the lens LE, the process moves to a lens edge position measurement process by the lens shape measurement unit 500. Under the control of the control unit 500, first, the slide base 512 is drawn forward from the retracted position, and the measuring elements 503 and 507 are moved to the measuring position based on the target lens shape data. Thereafter, the measuring elements 503 and 507 are brought into contact with the refractive surface by driving the motor 515. In this state, the lens LE is rotated once and the slide base 512 is moved back and forth based on the moving radius Rn of the target lens shape data SF. The first detector 527 detects the vertical movement position of the probe 503 at this time. Thus, the edge position on the front surface of the lens is obtained. At the same time, the vertical movement position of the probe 507 is detected by the second detector 533, and the edge position of the rear surface of the lens is obtained. The lens edge thickness in the target lens shape is obtained by the edge positions of the front and rear surfaces of the lens. The edge thickness information is used for calculation of a bevel locus during bevel processing (for example, calculation using a bevel apex locus that divides the edge thickness at a ratio of 3: 7 or the like).

  Further, in order to accurately know the edge position of the bevel shoulder during chamfering, the edge position is measured on a measurement locus 0.5 mm inside (or outside) of the radius vector length Rn of the target lens shape data SF. By measuring the edge positions of different radial length positions in the same meridian direction, it is possible to obtain the inclination of the refractive surfaces of the front surface and the rear surface of the lens. When the bevel shoulder has a taper in the beveling process, the edge position after the beveling process can be accurately and well known by obtaining the inclination of the front and rear surfaces of the lens near the target lens shape. By knowing the edge position after finishing, a small amount of chamfering can be accurately performed.

  When the lens shape can be measured, the process proceeds to roughing. When normal plastic is input as the lens material, the rough grindstone 30 is used as a roughing processing tool. When thermoplastic polycarbonate is input as the lens material, a roughing cutter 36 is used as a roughing processing tool. Hereinafter, a case where rough processing is performed by the roughing cutter 36 will be described as an example.

  Here, in the soft machining mode, the machining pressure during rough machining is not monitored and the machining pressure is changed, but the lens is rotated at a constant speed, and the cutting amount Δd during one rotation of the lens is substantially equal. The roughing cutter 36 is moved so as to be constant. The cutting amount Δd is set to an amount that does not cause an axis shift of the lens LE when the lens LE is roughly processed by the roughing cutter 36. This cutting amount Δd can be determined in advance by experiments. According to the experiment of the present inventor, in the case of a lens having an edge thickness of 10 mm or less, it was possible to process without axis deviation at Δd = 2 mm.

A machining operation with a substantially constant cutting amount Δd will be described with reference to FIG. The controller 600 controls the driving of the motor 214R from the distance data ERn from the lens rotation center to the lens LE periphery at the first lens rotation angle Θn (n = 1) until the cutting amount becomes a substantially constant amount Δd. The roughing cutter 36 rotating at high speed is moved to the lens side. The inter-axis distance Ln between the lens rotation axis (121, 152) and the rotation axis 304R of the roughing cutter 36 at this time is
Ln = ERn + TR (radius of the roughing cutter 36) −Δd
Can be calculated as In the case of the frame center mode, the geometric center of the lens outer shape and the lens rotation center do not coincide with each other. However, since the deviation between the two is usually not large, the amount of incision from the lens periphery also in the calculation of the inter-axis distance Ln. Δd becomes substantially constant. The controller 600 processes the amount Δd at the lens rotation angle Θn (n = 1), and then controls the driving of the motors 130 and 156 to rotate the lens LE at a constant speed. The inter-axis distance Ln is varied so that the cut amount becomes a substantially uniform amount Δd over the entire circumference. In the second rotation of the next lens,
Ln = ERn + TR-2 × Δd
To control the inter-axis distance Ln. Since most of the lens rotation angle at the end of the first rotation has already been removed, control is performed so that the cut amount gradually becomes the second cutting amount. With respect to the lens periphery processed at the first rotation, the lens periphery is excised with the same cutting amount Δd at the second rotation. Thereafter, according to the processing data until the shape of the target lens shape SF (Rn, θn) is left with a finishing allowance, the distance between the axes with a substantially constant cutting amount Δd over the entire circumference for every rotation of the lens. Ln is controlled. As a result, the peripheral edge of the lens LE is roughly processed without being displaced.

  In addition, if the above-mentioned cutting amount Δd is changed according to the edge thickness before roughing, the processing can be performed more appropriately. Since the load applied to the lens increases as the edge thickness increases, the cutting amount Δd decreases as the edge thickness increases, and conversely, the cutting amount Δd increases as the edge thickness decreases. The edge thickness of the lens LE before rough processing can be obtained as follows.

  For example, edge position information measured on the first measurement trajectory at the radial length Rn of the target lens shape data SF and the second measurement trajectory 0.5 mm inside (or outside) is used. As described above, by measuring the edge positions of different radial length positions in the same meridian direction, it is possible to obtain the inclination of the refractive surfaces of the lens front surface and the rear surface, and to obtain the inclination of the refractive surfaces of the lens front surface and the rear surface. Thus, the edge thickness at the lens periphery before processing (unprocessed fabric lens periphery) can be roughly obtained.

  FIG. 8 is a diagram for explaining a method of obtaining the edge thickness from the edge position measurement twice. In FIG. 8, Pf1 and Pr1 are edge measurement positions of the lens front surface and the lens rear surface at the moving radius Rn of the target lens shape data SF (Rn, θn) (n = 1, 2, 3,..., N). Pf2 and Pr2 are edge measurement positions of the lens front surface and the lens rear surface on a predetermined distance (for example, 0.5 mm) inside the moving radius Rn. A straight line Kf that passes through the edge positions Pf1 and Pf2 on the front surface of the lens and a straight line Kr that passes through the edge positions Pr1 and Pr2 on the rear surface of the lens. The edge thickness Te at the periphery of the lens LE at the lens rotation angle Θn (= θn) at the time of roughing is cut between the two straight lines Kf and Kr by a distance ERn (distance from the lens rotation center to the lens periphery). Can be approximately calculated as the distance TKe.

  Further, the edge thickness of the lens LE before rough processing uses the distance data (ERn, Θn) obtained by measuring the outer periphery of the first lens LE, and the front and rear surfaces of the lens LE are measured slightly inside the measurement locus. It may be obtained by measuring the lens shape.

  The cutting amount Δd corresponding to the edge thickness Te of the lens periphery is determined by experiment for each edge thickness, and the value or the calculation formula (Δd = A × Te + B) is stored in the memory 603 as shown in FIG. . In the calculation formula of FIG. 9, A is a coefficient according to the edge thickness Te, and B is a constant. At the time of rough machining, the edge thickness Te of the actual lens LE is obtained as described above, thereby determining the cut amount Δd corresponding to the edge thickness. In the case of an astigmatic lens, the edge thickness Te differs depending on the lens rotation angle Θn (= θn). In this case, the cut amount Δd may be constant based on the maximum edge thickness portion, but the cut amount Δd is controlled to be changed during processing according to the edge thickness for each lens rotation angle (for each radial angle). Also good.

  Further, in a lens having a different front curve and rear curve of the lens, the edge thickness of the lens periphery after rough processing changes with each rotation of the lens, so the cutting amount Δd is changed according to the edge thickness after processing with each rotation of the lens. May be. For example, as shown in FIG. 10, the edge thickness that changes at the rough machining portion of each lens rotation angle is obtained from the result of the edge position measurement. As shown in FIG. 8, by measuring at least two edge positions at each lens rotation angle at the lens front surface and the rear surface, the inclination of the lens front surface and the lens rear surface at each lens rotation angle can be obtained. This makes it possible to approximately obtain the edge thickness that changes at the rough machining portion of each lens rotation angle. In FIG. 10, in the first rotation of the lens, rough processing is performed with a cutting amount Δd1 corresponding to the edge thickness T1 of the lens periphery before rough processing, and in the second rotation, rough processing is performed with a cutting amount Δd2 corresponding to the edge thickness T2, and three rotations are performed. The coarse thickness after the rough machining that changes every rotation of the lens, such as rough machining with the cutting amount Δd3 corresponding to the edge thickness T3 and rough machining with the cutting amount Δd4 corresponding to the edge thickness T4 in the fourth rotation. The cutting amount Δd is sequentially changed in accordance with. Since the remaining amount Δdr is small with respect to the cutting amount corresponding to the edge thickness T5 in the final fifth rotation, rough machining is performed with the remaining cutting amount Δdr until the rough machining target Rr with a finishing allowance is obtained. . According to this processing method, since the number of rotations of the lens can be reduced, the processing time can be shortened.

  Further, the cutting amount Δd may be changed in accordance with the change in the distance ER from the center of lens rotation after processing for each rotation of the lens to the lens periphery. When the distance ER is long, the torque applied to the lens LE during processing increases, and when the distance ERn is shortened, the torque applied to the lens LE also decreases. Accordingly, every time the lens LE rotates once and the distance ER becomes shorter, the cutting amount Δd is gradually increased. The distance ER to the lens periphery for each rotation of the lens can be calculated from the lens outer shape data before the first processing and the cutting amount Δd for each rotation. According to this method, the time until rough machining is completed is reduced, and the machining time is shortened accordingly.

  After the roughing is finished, finishing is performed by the finishing grindstone 31 as in the prior art. When chamfering is designated, chamfering of the corner portion after finishing is performed by the chamfering grindstones 32 and 33.

  In the above-described soft processing mode, the case where thermoplastic polycarbonate is input as the lens material has been described. However, when normal plastic is designated, the rough grindstone 30 is used. When the lens material is different, the processing capability of the roughing tool is also different depending on the hardness or the like, so that the axial deviation can be suppressed by changing the cutting amount Δd at the time of roughing according to the lens material. For example, a plastic high-refractive lens is a material that is harder to process with a cutter than a polycarbonate or a normal plastic lens. For this reason, when processing a plastic high-refractive lens, the cut amount Δd is reduced relative to the polycarbonate. The cutting amount Δd in this case may be determined in advance as a value that does not cause an axis deviation through experiments or the like. Furthermore, by performing the control to change the cutting amount Δd according to the edge thickness described above, it is possible to perform processing with a further reduced axial deviation.

  Next, the case where the lens LE is not a water repellent lens but a normal lens processing mode is selected will be briefly described. In this processing mode, the lens outer shape measurement is not performed, and the rough edge processing is started after the lens edge position measurement. At the time of rough machining, the control unit 600 moves the rotating shaft 304R of the rough machining cutter 36 toward the lens regardless of the outer shape of the lens circumference, and processes the lens circumference by the rough machining cutter 36 that rotates at high speed. At this time, the controller 600 monitors the drive current of the motor 214R by the driver 214aR, and detects the machining pressure during rough machining based on the amount of the current. When the rotation shaft 304R is moved to the lens side and the processing amount of the lens increases, the processing pressure also increases. When the processing pressure (drive current of the motor 214R) reaches a predetermined upper limit value, the rotation speed of the lens is decreased (including the case where the rotation is stopped). Alternatively, the movement of the rotating shaft 304R (rough machining cutter 36) to the lens side is stopped (or returned slightly), and a decrease in the machining pressure is awaited. This processing pressure adjustment control may be performed by both the lens rotation speed and the movement of the rotation shaft 304R. When the processing pressure reaches a predetermined lower limit value, the rotation of the lens and the movement of the rotating shaft 304R to the lens side are resumed, and the periphery of the lens LE is processed again by the roughing cutter 36.

  In the case of a lens that can secure a holding force by using the leap tape 51, since the axial displacement is unlikely to occur even if the processing pressure is high, the peripheral edge of the lens LE is processed with a small number of rotations by adjusting the processing pressure, and the processing time Becomes shorter. The inter-axis distance between the lens rotation axis (121, 152) and the rotation axis 304R of the roughing cutter 36 is controlled according to the roughing data that leaves the finishing allowance.

  A lens that is slippery, such as a water repellent lens, can be processed with reduced axial deviation by using the soft processing mode. On the other hand, in the case of a lens that can secure a holding force by using the leap tape 51, it can be processed in a short time by using a normal processing mode.

It is a schematic block diagram of the process part of an eyeglass lens processing apparatus. It is a figure explaining the structure of the processing tool which a lens grinding part has. It is a schematic block diagram of a lens shape measurement unit. It is a control system block diagram of an apparatus. It is a figure explaining blocking of the cup to lens LE before processing. It is a figure explaining the measurement of the peripheral outline of lens LE. It is a figure explaining the processing operation by substantially constant cutting amount (DELTA) d. It is a figure explaining the method to obtain edge thickness from twice edge position measurement. It is the figure which showed the relationship of cutting depth (DELTA) d according to edge thickness of a lens periphery. It is a figure explaining the example which changes cutting amount (DELTA) d according to the edge thickness after a process for every rotation of a lens. It is a flowchart explaining operation | movement of this apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Display part 11 Input part 30 Coarse grindstone 31 Finishing grindstone 36 Roughing cutter 121,152 Lens rotating shaft 130,156 Pulse motor 210L, 210R Left and right slide base 214L, 214R Pulse motor 217L, 217R Encoder 300L, 300R Lens grinding part 304L, 304R Processing Tool Rotating Shaft 500 Lens Shape Measuring Unit 600 Control Unit 650 Eyeglass Frame Measuring Device

Claims (6)

It has an inter-axis distance variation means for varying the inter-axis distance between the lens rotation axis that holds the spectacle lens and is rotated by the rotation means, and the processing tool rotation axis that processes the periphery of the lens, and is obtained from the lens shape data. In an eyeglass lens processing apparatus that processes the lens periphery by controlling the operation of the inter-axis distance varying means based on data, the amount of cut during the one rotation of the lens is substantially constant by rotating the lens rotation shaft at a constant speed. An eyeglass lens processing apparatus comprising control means for controlling the operation of the inter-axis distance varying means so that 2. The eyeglass lens processing apparatus according to claim 1, further comprising means for measuring or inputting lens outer shape data before processing with respect to a lens rotation axis, wherein the control means is configured to make the cutting amount substantially constant based on the lens outer shape data. An eyeglass lens processing apparatus for controlling the operation of the inter-distance changing means. The eyeglass lens processing apparatus according to claim 1 or 2, further comprising a selection unit that selects whether or not to perform a process of making the cut amount substantially constant, and the control unit is selected to perform a process that does not make the cut amount substantially constant. In this case, the spectacle lens processing apparatus is characterized in that at least one of the rotating means and the inter-axis distance varying means is controlled to adjust the processing pressure by the processing tool to perform lens periphery processing. The spectacle lens processing apparatus according to claim 1 comprises lens outer shape measuring means for measuring lens outer shape data before processing with respect to the lens rotation axis, and selection means for selecting whether or not processing for making the cutting depth substantially constant is performed. The control means operates the lens outer shape measuring means before rough machining to obtain lens outer shape data when machining with a substantially constant cut amount is selected, and the cut amount based on the acquired lens outer shape data. When the processing that does not make the cutting depth substantially constant is selected by controlling the operation of the inter-axis distance varying means so that is substantially constant, the rotation means and the inter-axis distance varying means are selected. An eyeglass lens processing apparatus that controls at least one of the lens and adjusts a processing pressure by a processing tool to perform lens periphery processing. 5. The eyeglass lens processing apparatus according to claim 1, further comprising at least one of an edge thickness detecting means for detecting an edge thickness of a lens peripheral edge before rough processing and a material input means for inputting a lens material. Is a spectacle lens processing apparatus that changes the cutting amount based on at least one of edge thickness and lens material. 5. The eyeglass lens processing apparatus according to claim 1, wherein an edge position measuring means for measuring at least two edge positions at different distances in the lens rotation angle by bringing a probe into contact with the front and rear surfaces of the lens, and the edge An edge thickness calculating means for obtaining an edge thickness of the rough processed portion based on the measurement result of the position measuring means, and the control means changes the cut amount every time the lens is rotated based on the edge thickness of the rough processed portion. An eyeglass lens processing apparatus.