JPH05277920A - Lens grinding device and grinding - Google Patents

Abstract

PURPOSE:To provide a lens grinding device and a lens grinding method to improve grinding efficiency of a processed lens by a less expensive method and to shorten grinding time. CONSTITUTION:A lens grinding device is constituted of a form data measuring means 100, a lens grinding means 200, a computation control circuit, 300 and a data input means 400. The computation control circuit 300 is constituted with microprocessors and contains a data correction means 310, a computing means 320, a grinding data 330 to control the lens grinding means 200, a lens axis rotation speed data 340 and a radius vector distance displacement amount computing means 350. By the radius vector distance displacement amount computing means 350, a displacement amount of radius vector distance from a standard point changing for every specified rotation angle of a lens frame is computed in accordance with a form data. Grinding processing is controlled by controlling rotation speed of a lens axis holding a lens before processing in a size in inverse proportion to the computed displacement amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens grinding apparatus and a lens grinding method for grinding an unprocessed lens into a shape matching the lens frame based on the shape data of the lens frame of the frame.

[0002]

2. Description of the Related Art In the case of grinding the outer peripheral shape of a circular lens so as to match the spectacle frame, a lens grinding apparatus for grinding the peripheral edge of a lens before processing with a cylindrical grindstone, based on the lens frame shape data of the spectacle frame. Is used. For example, in International Publication WO88 / 04974, a lens is pressed from the front and rear surfaces and held by a lens shaft, the lens shaft is rotated at a constant speed by an AC motor, and the rotation state of the lens shaft is read by an encoder. There is disclosed a lens grinding device that grinds a pre-processed lens into a shape matching a lens frame while controlling a Y-axis motor between a grindstone and a lens axis based on the rotation angle information.

Such a lens grinding device has an advantage that the peripheral edge processing of the spectacle lens can be directly performed based on the shape measurement data of the lens frame of the spectacle frame.
However, on the other hand, in terms of the efficiency of grinding, there are the following disadvantages. Here, a defect of the grinding process by the conventional method will be described with reference to FIG.

Conventionally, a cylindrical grindstone 261 has been used for grinding the spectacle lens 201. In FIG. 8, the distance H between the rotation center Od of the grindstone 261 and the rotation center Os of the eyeglass lens 201 and the radius R of the grindstone 261 are shown. On the side surface of the grindstone 261, the eyeglass lens 201
The end surfaces of the grindstone 261 and the spectacle lens 201 are rotated by bringing them into contact with each other with a predetermined pressure. Eyeglass lens 2 at this time
By rotating 01 (lens axis) and simultaneously driving the Y-axis motor based on the lens frame shape data (θj, rj) to move the lens axis up and down, the eyeglass lens 201 is pressed against the grindstone 261. Eyeglass lens 201
Is ground into the lens frame shape of the frame.

[0005]

However, when the displacement amount Δr / Δθ of the radial distance r of the spectacle lens 201 is large, the driving amount of the Y-axis motor, that is, the spectacle lens 2 is used.
The change in the distance H by which 01 is moved in the vertical direction also becomes large.
What happens is that the center of rotation Od of the grindstone 261 also has a radius R
Is also fixed. Since the rotation of the lens axis and the movement of the lens axis in the vertical direction are controlled at the same time, the displacement amount Δr / Δθ of the eyeglass lens 201 is smaller than the displacement amount of the radial distance rj. In big places,
The cutting pressure on the spectacle lens 201 decreases, and the cutting efficiency also decreases.

That is, the radial distance r of the spectacle lens 201
If the rotational speed of the lens shaft is uniformly increased with reference to a portion having a small displacement amount, the cutting residue will inevitably occur at a portion having a large displacement amount of the radial distance rj. In this way, in the grinding process, it is necessary to consider the balance between the rotation of the lens axis and the vertical movement of the lens axis,
If the rotation speed of the lens shaft is higher than the moving speed of the lens shaft in the vertical direction, the accuracy of grinding the end surface of the spectacle lens 201 becomes low.

Therefore, since the shape of the ground lens needs to be corrected, if the rotational speed of the lens axis is fixed, the grinding time of the spectacle lens 201 becomes long as a result. On the other hand, if the rotational speed of the lens shaft is determined with reference to a portion having a large radial distance displacement, uncut residue is less likely to occur, but the grinding time for finishing the spectacle lens 201 to the final shape becomes longer. there were.

The present invention has been made in view of the above points, and an object of the present invention is to provide a lens grinding apparatus which improves the grinding efficiency of a processed lens by an inexpensive method. Another object of the present invention is to provide a lens grinding method that can shorten the grinding time.

[0009]

In order to solve the above-mentioned problems, the present invention provides a lens grinding apparatus for grinding an unprocessed lens into a shape corresponding to the lens frame based on the shape data of the lens frame of the frame. Shape data setting means for setting shape data including a radial distance for each rotation angle from a reference line and a reference point set on the lens frame,
Calculating means for calculating the amount of displacement of the radial distance from the reference point that changes at each predetermined rotation angle of the lens frame based on the shape data; and the rotation speed of the lens shaft that holds and rotates the unprocessed lens. Is determined by a magnitude that is inversely proportional to the magnitude of the displacement amount, and the grinding process is controlled by the rotating grindstone by controlling the speed of the lens axis according to the rotation speed data determined by the speed determining means. A lens grinding control means is provided, and a lens grinding device is provided.

Further, in the present invention, in order to shorten the grinding time, in the lens grinding method for grinding the unprocessed lens into a shape matching the lens frame based on the shape data of the lens frame of the frame, the lens frame Set the shape data including the radial distance for each rotation angle from the reference line and the reference point set in, to calculate the displacement amount of the radial distance from the reference point for each predetermined rotation angle of the lens frame, There is provided a lens grinding method characterized by controlling the rotation speed of a lens shaft holding the unprocessed lens and controlling grinding by a rotating grindstone in a size inversely proportional to the calculated displacement amount. It

[0011]

The function of the present invention is that the rotational speed of the lens shaft is controlled according to the amount of vertical movement of the lens shaft.
This makes it possible to shorten the time required to grind the spectacle lens into the lens frame shape. That is, if the displacement amount is small, the rotation speed is increased, and if the displacement amount is large, the rotation speed is decreased. In this way, the grinding accuracy in lens grinding can be improved and the grinding time can be shortened.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of a lens grinding device.

The lens grinding device comprises a shape data measuring means 1
00, lens grinding means 200, arithmetic control circuit 300, and data input means 400 as main elements. The shape data measuring unit 100 includes a frame shape measuring unit 110 and a frame shape measuring unit 1 that measure the shape of the lens frame.
The frame shape measuring circuit 120 connects the arithmetic control circuit 300 with the frame shape measuring circuit 120. The shape data measuring means 100 measures the shape data of the frame in which the processed lens is framed.

The lens grinding means 200 has a lens grinding section, a motor drive circuit, etc., and holds the lens to be processed on a rotary shaft which coincides with the optical axis of the lens based on the grinding data, as will be described later. Lens axis motor 23 for grinding
2 and the Y-axis motor 252, and drive circuits 232a and 252a for driving these motors.

The arithmetic control circuit 300 has a microprocessor configuration, and includes data correction means 310 and arithmetic means 3.
20, a grinding data 330 for controlling the lens grinding means 200, a lens axis rotation speed data 340, and a radial distance displacement amount calculation means 350. The data correction means 310 inverts the shape data of one lens frame whose origin is the geometric center of the lens frame with respect to the axis of symmetry of the left and right lens frames of the frame to calculate a pair of lens frame shape data of the frame, It is corrected to a pair of grinding data 330 whose origin is the lens optical center in the lens frame based on the shift amount data. The calculation means 320 inverts the shape data of one lens frame and converts it into the other shape data, and the radial distance displacement amount calculation means 350 further changes based on this shape data for each predetermined rotation angle of the lens frame. The amount of displacement of the radial distance from the reference point is calculated.

The data inputting means 400 stores numerical value keys (inputting quantity inputting means) 401 for inputting a moving amount, a selection key 402 for selecting whether the lens is right or left, and frame frame shape data in an IC card or the like. The IC card reading device (shape data reading means) 403 reads shape data from the IC card. That is, the shape data is measured by the shape data measuring unit 100, and the shape data is measured in advance.
IC card reading device 403
May be read by.

FIG. 2 is a detailed view showing the frame shape measuring unit 110. In order to set the shape data of the lens frame in which the processed lens is framed, the spectacle frame 111 is fixedly held by a frame holding member at a predetermined position on a frame table (not shown). At this position, the tracing stylus 112 abuts on the inner circumferential groove of the lens frame of the spectacle frame 111. The tracing stylus 112 is fixedly provided on a rotary plate 114 that rotates around a rotary shaft 113, and is constrained by a slide plate 115 that constitutes a slide mechanism.
It can be moved along the inner circumferential groove of the lens frame of the eyeglass frame 111. The rotation angle when the tracing stylus 112 moves is defined by the angle at which the tracing stylus motor 116 rotates the rotary shaft 113.
The amount of displacement from the reference position of 2 is obtained by further converting the amount of sliding of the slide plate 115 in the left-right direction in the drawing into a rotation angle,
It can be transmitted to the potentiometer 117 for measurement. The rotary encoder 118 measures the rotation angle of the rotary plate 114 from the reference position, and the origin position detection circuit 119 constituted by a photo interrupter can detect the origin position of the tracing stylus motor 116.

FIG. 3 is a block diagram showing the frame shape measuring circuit 120. The measuring element 112 is attached to the eyeglass frame 11
The motor drive circuit 11 is applied to the inner circumference of the first lens frame.
A rotation command is given to 6a to drive the tracing stylus motor 116. The tracing stylus 112 includes a rotating shaft 113, a rotating plate 114,
Also, the eyeglass frame 1 moves together with the slide plate 115.
It moves along the inner circumferential groove of 11 rims. The rotation angle θ of the rotary plate 114 at this time is output from the rotary encoder 118 and counted by the counter 118a. Also,
A displacement amount r of the probe 112 from the measurement reference position is output from the potentiometer 117, and the A / D conversion circuit 117a is output.
Are converted into digital values by. When the tracing stylus 112 makes one revolution in the inner circumferential groove of the rim of the spectacle frame 111, the counter 118a outputs one revolution signal, and the arithmetic control means 300 gives a stop command to the motor drive circuit 116a.

A spectacle frame left / right eye determination circuit 119
a is for determining which of the left and right rims of the eyeglass frame 111 is in contact with the tracing stylus 112, and determines the count value of the rotation angle θ and the digital value of the displacement amount r by a predetermined value of the arithmetic control circuit 300 described later. Store in the storage area.

In the frame shape measuring section 110, the tracing stylus moves along the inner circumferential groove of the lens frame while maintaining a predetermined contact pressure, and the shape data of the lens frame is read. The displacement amount r of the tracing stylus 112 corresponds to the length of the radius vector of the lens frame of the spectacle frame 111 (hereinafter, simply referred to as the radius vector), and the rotation angle θ of the rotating plate 114 corresponds to the rotation angle of the frame of the spectacle frame 111. Equivalent to.

FIG. 4 is a detailed view showing a lens grinding section which constitutes the lens grinding apparatus of FIG. Further, FIG. 5 is a block diagram showing a lens grinding circuit. In the lens grinding portion of FIG. 4, the horizontal direction is the Z axis and the vertical direction is the Y axis. The lens grinding unit includes a storage box 202 that supports the lens 201 to be processed and is movable in the Z-axis direction. The storage box 202 is moved in the Z-axis direction on the base 203 of the lens grinding unit, and the base 203 is further moved in the Y-axis direction, whereby a predetermined amount of processing is performed on the initially unprocessed lens 201. To enable. The grinding pressure adjusting mechanism 210 adjusts the grinding pressure of the unprocessed lens 201 and is positioned in the Y-axis direction of the base 203 on which the storage box 202 is placed. The Z-axis drive mechanism 220 is used for the storage box 20.
2 together with the unprocessed lens 201 in the left-right direction (Z
Axis). The processed lens rotation mechanism 230 is
A lens shaft 231 for rotating the unprocessed lens 201 is provided, and this lens shaft 231 is the lens chuck mechanism 2 to be processed.
The lens 201 is rotated while being held by the lens 40. The Y-axis direction drive mechanism 250 is used for the unprocessed lens 20.
The position of 1 in the Y-axis direction is adjusted by the sensor bar 251 fixed to the base 203 and moved by a predetermined amount. The diamond wheel 261 is rotatably provided at a predetermined speed by a diamond wheel rotating mechanism 260 for grinding the unprocessed lens 201.

The base 203 is connected by the wire ropes 211a and 211b of the grinding pressure adjusting mechanism 210 and is constantly lifted upward so that the lens 201 to be processed comes into contact with the diamond wheel 261 at a predetermined grinding pressure. Have control over. Therefore, the grinding pressure adjusting motor 21
2 is provided, and the origin position detection sensor 213 detects the origin positions of the wire ropes 211a and 211b.
The unwinding length of the wire rope 211a by the grinding pressure adjusting motor 212 is detected by the winding amount detection sensor 214. The cutting pressure adjusting spring 2 inserted in the sleeve 215 is provided in the middle of the wire ropes 211a and 211b.
16 are provided.

As shown in FIG. 5, the origin position detection circuit 21
3a and the detection signals of the winding amount detection circuit 214a are output to the arithmetic and control circuit 300, and the arithmetic and control circuit 300 calculates the grinding pressure adjustment signal accordingly. The rotation amount of the grinding pressure adjusting motor 212 is adjusted according to the adjustment signal input to the motor drive circuit 212a.

Pulse motor 2 of Z-axis drive mechanism 220
The unprocessed lens 201 is subjected to a plurality of grinding parts (grinding stones) formed on the outer peripheral surface of the diamond wheel 261 by means of 21, for example, a rough grinding part for roughly grinding the unprocessed lens 201, and bevel grinding (processing of V groove). It is moved to each position of the bevel grindstone part for. The pulse motor 221 of the Z-axis direction drive mechanism 220 has a pulley 223a,
The clutch 22 via the belt 222 and the pulley 223b.
4 and the pulley 2 on the opposite side of the clutch 224.
The moving plate 22
The storage box 202 is positioned in the Z-axis direction via 7. The amount of movement of the belt 226 via the pulley 228 is converted into the rotation angle of the light shielding plate 229a, and the origin position in the Z-axis direction is detected by the photo interrupter 229.

As shown in FIG. 5, the photo interrupter 2
The origin position detected by 29 is the origin position detection circuit 229a.
Is output to the arithmetic control circuit 300, and the arithmetic control circuit 300 calculates a Z-axis position command signal according to the grinding data. Then, the Z-axis pulse motor 221 rotates according to a command signal input to the motor drive circuit 221a.

The lens axis pulse motor 232 of the lens rotating mechanism 230 rotates the lens 201 to be processed around its lens axis 231. The rotation of the lens axis pulse motor 232 is controlled by the four pulleys 233a-23
It is transmitted to the lens shaft 231 by 3d and two belts 234a and 234b. Diamond wheel 261
On the other hand, the rotation angle of the unprocessed lens 201 is commanded based on the lens axis rotation speed data 340. That is, according to the present invention, the encoder is not attached to the lens shaft 231, and the lens shaft 231 is controlled by the pulse motor 232 in place of the conventional AC motor. Therefore, the prior art (International Publication WO88 / 04974). No.).

The lens pressing motor 241 of the lens chuck mechanism 240 to be processed is mounted on the lens shaft 231 before the processing of the lens 2 before processing.
01, or a motor that rotates so as to remove the processed lens, including a pulley 243a and a belt 242.
And the lens shaft 231 via the pulley 243b.

As shown in FIG. 5, the motor drive circuit 241
From the arithmetic and control circuit 300 for a, the unprocessed lens 201
A command signal based on the replacement command is supplied to the motor drive circuit 241a at a predetermined timing, and the pre-processing lens 2
01 can be exchanged.

The Y-axis servomotor 252 of the Y-axis direction drive mechanism 250 is connected to one end of a screw shaft 254 parallel to the Y-axis with a belt 255 via pulleys 253a and 253b.
The screw shaft 254 is rotated at a predetermined speed. And
The switching bar 256 screwed to the screw shaft 254 moves in the Y-axis direction when the Y-axis servomotor 252 rotates, and presses the switching button 257 from below in FIG. 4 with an appropriate pressure. .. The switching button 257 is provided on one end side of the shield rod 257a, and a photo interrupter 257b for detecting the end of grinding is provided on the other end side of the shield rod 257a. The shield rod 257a is attached to the tip end portion of the sensor bar 251 so as to be movable in the Y-axis direction via a compression spring having a predetermined elasticity, and comes into contact with the switching bar 256 to push up the sensor bar 251 in the Y-axis direction. And regulates the positions of the storage box 202 and the base 203 in the Y-axis direction. The photo interrupter 257b is the shield rod 25.
When 7a is pushed by the switching bar 256 and the shield rod 257a is moved, the center position of the pre-processing lens 201 is moved downward in FIG. 4 in accordance with the movement amount. The other end of the screw shaft 254 has a belt 258.
Encoder 25 for detecting the Y-axis direction position by
9 is provided.

As shown in FIG. 5, the movement amount detected by the encoder 259 is output from the movement amount detection circuit 259a to the counter circuit 259b, and this counter circuit 259 is output.
The count value in b is sent to the arithmetic and control circuit 300. As a result, the movement amount of the shielding rod 257a is obtained, and the rotation center of the unprocessed lens 201 and the diamond wheel 261 are obtained.
The distance to the rotation center of can be measured. The Y-axis servomotor 252 is driven by the grinding data of the lens frame instructed to the motor drive circuit 252a, and is controlled in relation to the rotation angle θ of the unprocessed lens 201. And
When the unprocessed lens 201 is ground over 360 °, the shield bar 257a is not pushed by the switching bar 256 by the photointerrupter 257b for detecting the end of grinding, and a signal is output from the end of grinding detection circuit 257c. In response to this signal, the arithmetic and control circuit 300 reverses the rotation direction of the unprocessed lens 201, and further commands the timing for ending the grinding.

In the diamond wheel rotating mechanism 260, the pulley 264 is driven when the grindstone rotating shaft motor 262 is driven.
The diamond wheel 261 is rotated via a, the belt 263, and the pulley 264b.
The lens shaft 231 sandwiching is rotated at the same time. As shown in FIG. 5, the grindstone rotary shaft motor 262 is rotationally controlled at a predetermined speed in accordance with a command from the arithmetic control circuit 300 to the motor drive circuit 262a. In this way, the grindstone is brought into contact with the peripheral portion of the unprocessed lens 201, and the grinding is executed while rotating each other.

FIG. 6 is a block diagram showing an arithmetic control circuit 300 for controlling the frame shape measuring section 110 and the lens grinding means 200. The CPU 301 performs predetermined arithmetic processing such as the amount of displacement of the radial distance from the reference point that changes for each predetermined rotation angle of the lens frame based on the input frame shape measurement data and the like, and the processing result is stored in the RAM 302. To be done. The ROM 303 has an arithmetic program for determining the rotational speed of the lens shaft 231 and an arithmetic program for inverting the shape data of the lens frame, which will be described below.
A calculation program for obtaining the left and right lens optical centers in the lens frame based on the amount of displacement data, a calculation program for obtaining an envelope corresponding to the radius value of the diamond wheel 261 from the shape data, and the central axis of the lens axis is the grindstone rotation. So that it is located on the envelope with respect to the central axis of the axis,
A calculation program for converting the lens frame shape data into grinding data is stored.

Next, a grinding procedure by the lens grinding apparatus of the present invention shown in FIGS. 1 to 6 will be described.
FIG. 7 is a flowchart showing an embodiment of the lens grinding method. In the figure, the numerical value following S indicates a step number. In these processes, the diamond wheel 261 of FIG. 4 is rotated at a predetermined speed and the lens shaft 231 is rotated.
The rotation speed and the position in the vertical direction are simultaneously controlled.

[S1] The radial distance is calculated for each predetermined angle from the reference line and the reference point set on the lens frame, and the shape data is set. Shape data is frame shape measuring circuit 1
It is read from the RAM 20 into the RAM 302, or is set by using the IC card from the data input means 400. Here, the reference line and the reference point can be set arbitrarily.

[S2] The set shape data is corrected by the data correction means 310 into shape data whose origin is the optical center of the lens set in the lens frame. The correction data is calculated from the shape data given as polar coordinate data, but the shape data converted into the rectangular coordinate data may be used.

[S3] Based on the shape data of step S2, the displacement amount of the radial distance that changes for each predetermined rotation angle of the lens shaft 231 is calculated. In the calculation of this displacement amount, the shape data of step S1 can be used, but the shape data used at the time of lens grinding is correction data with the optical center of the lens as the origin, and therefore the calculation process is facilitated. In order to do so, it is desirable to use modified shape data.

[S4] Based on the displacement amount of the radial distance obtained in step S3, the lens shaft 231 for each predetermined rotation angle.
Determine the rotation speed of. A rotation speed table can be used to determine the rotation speed.

That is, the rotation speed ω corresponding to the displacement amount Δr / Δθ of the radial distance r of the unprocessed lens 201 of the spectacles is set, and the speed data (ωi, θi) for each rotation angle θ from the reference line is set. ) Is stored in the RAM 302 as lens axis rotation speed data 340. In this case, the displacement amount of the radial distance can be read by the number of pulses instead of the length data.

[S5] The optical center of the unprocessed lens 201 is attached so as to coincide with the lens axis 231, and the speed of the lens axis 231 is controlled by the speed data determined in step S4. The lens grinding is executed while controlling the position in 1) based on the shape data corrected in step S2.

If the unprocessed lens 201 is ground into the lens frame shape as shown in FIG. 8 in this manner, the vertical movement amount of the lens shaft 231 is large at a portion where the displacement amount Δr / Δθ of the radial distance is large. Even so, the lens shaft 231 can be controlled so as to rotate slowly in proportion thereto, so that the grinding residue is reduced. On the contrary, the radial distance displacement Δr / Δ
At a position where θ is small, the lens shaft 231 can be rotated at high speed, and the grinding efficiency can be improved.

Even if the set shape data is not corrected (step S2) as in the present embodiment, step S1 is performed.
It is also possible to grind directly on the basis of the shape data. However, at this time, it is necessary to attach the unprocessed lens to the lens shaft 231 so as to match the reference point set in step S1. Then, in step S5, the lens shaft 231
The lens mounting position on the lens is also determined by this reference point.

Further, according to the present invention, by storing the template data in advance, for example, the actual flat plate 2-1585.
It can also be applied to the lens grinding device by the copying process disclosed in Japanese Patent No. 9 or the like. However, it is necessary to use a pulse motor for the lens shaft rotation motor.

[0043]

As described above, according to the present invention, by controlling the rotation speed of the lens shaft according to the amount of vertical movement of the lens shaft, it is possible to improve the performance of the Y-axis motor and the lens-axis rotation motor. It is possible to provide a lens grinding device that can reduce the lens grinding time by an inexpensive method.

Further, since the lens grinding method of the present invention can reduce the grinding residue, the processed spectacle lens can be put into the frame without modification.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a lens grinding device.

FIG. 2 is a detailed view showing a frame shape measuring unit.

FIG. 3 is a block diagram showing a frame shape measuring circuit.

FIG. 4 is a detailed view showing a lens grinding section that constitutes the lens grinding apparatus.

FIG. 5 is a block diagram showing a lens grinding circuit.

FIG. 6 is a block diagram showing an arithmetic control circuit.

FIG. 7 is a flowchart showing an embodiment of a lens grinding method.

FIG. 8 is a diagram showing a processed lens when there is a displacement amount of a radial distance set for the unprocessed lens.

[Explanation of symbols]

 100 shape data measuring means 200 lens grinding means 300 arithmetic control means 340 lens axis rotation speed data 350 radial distance displacement amount calculating means 400 data input means

Claims (4)

[Claims] 1. A lens grinding apparatus for grinding an unprocessed lens into a shape matching the lens frame based on the shape data of the lens frame of the frame, wherein a reference line and a reference point set in the lens frame Shape data setting means for setting shape data including a radial distance for each rotation angle, and a displacement amount of the radial distance from the reference point that changes for each predetermined rotation angle of the lens frame based on the shape data. Calculating means for calculating, speed determining means for determining the rotation speed of the lens shaft for holding and rotating the unprocessed lens by a magnitude inversely proportional to the magnitude of the displacement amount, and rotation determined by the speed determining means A lens grinding control means for controlling a grinding process by a grindstone rotating by controlling a speed of a lens axis according to speed data, and a lens grinding device. 2. A lens grinding apparatus for grinding an unprocessed lens into a shape matching the lens frame based on shape data of a lens frame of a frame, wherein a reference line and a reference point set on the lens frame are used. Shape data setting means for setting shape data including a radial distance for each rotation angle, and shape data correction means for correcting the shape data into grinding data having the optical center of the lens set in the lens frame as an origin. A calculation means for calculating a displacement amount of a radial distance from the reference point or the origin that changes at each predetermined rotation angle of the lens frame based on the shape data or the correction data; Speed determining means for determining the rotation speed of the lens shaft to be held and rotated by a magnitude inversely proportional to the magnitude of the displacement amount; and a rotation speed determined by the speed determining means. Lens grinding apparatus comprising: the lens grinding control means for controlling the grinding by the grinding wheel that rotates in the speed control of the lens axis in accordance with the speed data. 3. The shape data setting means uses polar coordinate data (θi, r) based on a radial distance ri for each rotation angle θi.
i) is set (i is 0, 1, ... N), the calculating means calculates the difference Δri between the adjacent radial distances r _i and r _{i + 1} , and the speed determining means calculates the difference Δri. The lens grinding apparatus according to claim 1 or 2, wherein a rotation speed ω that is inversely proportional is determined. 4. A lens grinding method for grinding an unprocessed lens into a shape corresponding to the lens frame based on shape data of a lens frame of the frame, wherein a rotation from a reference line and a reference point set in the lens frame is performed. The shape data including the radial distance for each angle is set, the displacement amount of the radial distance from the reference point is calculated for each predetermined rotation angle of the lens frame, and the size is inversely proportional to the calculated displacement amount. The lens grinding method is characterized in that the rotational speed of the lens shaft holding the unprocessed lens is controlled to control the grinding processing by the rotating grindstone.