JP2002355744A - Spherical surface copy grinding-polishing method and spherical surface copy grinding-polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the spherical center position of machining to improve shape transferability and surface accuracy by controlling the temperature of a machining fluid so as to be kept constant. SOLUTION: This spherical surface copy grinding-polishing device has a polishing plate 4 for polishing the spherical surface of a polished object; a rotating means 5 for holding and rotating the polishing plate 4; a holding means 13 for rotatably holding the rotating means 5; a rocking means 16 for putting the polishing plate 4 in rocking motion; a machining fluid supply means for supplying a machining fluid to the polishing face of the polishing plate 4; a pressurizing means 25 for pressuring the polished object in the spherical center direction of the polishing plate while holding the polished object rotatably; and a control means for controlling the temperature of the machining fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an object to be polished (hereinafter referred to as a lens) made of a brittle material such as an optical element such as a lens.
And a device for performing high-precision spherical copying grinding and polishing.

[0002]

2. Description of the Related Art Heretofore, lenses have been produced mainly by copying in which a polishing allowance is predicted mainly based on a pressing force, a processing time and the like. In addition, machining equipment is roughly divided into upper shaft swing and lower shaft swing, and furthermore, inclined type and vertical type, etc., but it is generally simple and has been produced while maintaining quality and accuracy depending on the skills of the processor. ing. However, in recent years, dimensional accuracy and surface accuracy of the center thickness (medium thickness) of the lens have been required with high accuracy, and it has become difficult to control the dimensional accuracy and surface accuracy of the medium with the above-mentioned conventional method. .

[0003] As a conventional apparatus for performing lens thickness control that issues a command to continue or end processing while measuring the thickness of a lens being processed, there is an apparatus described in Japanese Patent Publication No. 4-4094. .

FIG. 7 shows a lens polishing apparatus provided with an automatic polishing judgment device described in this publication. This device is roughly classified into a polishing plate rotation swinging mechanism L, a polishing holder fixed pressing mechanism M, and an automatic polishing determination device N.

The polishing plate rotating and swinging mechanism L includes a cylindrical box 1.
The spindle 103 of the drive shaft 102 is inserted into the center portion of the spindle 08 via a bearing 115, and a polishing dish 101 for polishing a lens 200 having a spherical dent is screwed onto the upper end of the spindle 103, while the drive shaft is screwed. V at the lower end of 102
A pulley 104 is attached, and is driven via a V pulley 105 and a belt 107.
The V pulley 105 is attached to a drive shaft 106 that is linked to a spindle motor 109, and the polishing plate 101 can be freely rotated by driving the spindle motor 109. A center shaft 112 is mounted on the upper portion of the sleeve 111 via a bearing 115. The entirety of the cylindrical box 108 in which the polishing plate rotation swinging mechanism L is provided is interlocked with the spindle motor 109. It swings like a pendulum through the swing post 116 and the swing cylinder 117 which are present.

[0006] The polishing holder fixing and pressing mechanism M is a metal 1
A polishing holder 124 is attached to a lower end of a holder shaft 120 attached to the holder arm 121 via 22. The holder arm 121 is constantly pressurized by being elastically attached to the upper protruding end of the holder shaft 120 via a pressurizing spring 123. By this pressing, the polishing holder 124 constantly presses the lens 200 on the polishing plate 101. That is, the polishing holder fixing / pressing mechanism M fixes the polishing holder 124 and constantly presses the ball of the polishing plate 101 from a certain direction (vertical direction) to polish the polishing lens 200 with the polishing plate 101. This is a mechanism for keeping a pressurized state between the holders 124.

The automatic polishing measuring device N is attached to a polishing holder fixed pressure mechanism M,
have. The dial gauge 140 is electrically driven through a signal extraction lead wire 131 and is operated by a determination terminal 133 attached to an upper portion. That is, the pressing operation of the measuring terminal 133 activates the electric contacts in the dial gauge 140 and generates a stop signal.

[0008] An adjustment knob 132 for the electrical contact performs adjustment for setting a polishing measurement value in advance. By setting the automatic polishing measurement device N in accordance with the scale of the dial gauge 140 using the adjustment knob 132, the needle is moved to the scale adjusted by the pressing operation of the determination terminal 133, and a stop signal is issued. Further, the adjusting bolt 134 is connected to the measuring terminal 133 via the detecting plate 135.
Is fixed to the upper part of the protruding end. This adjustment bolt 134
Adjusts the polishing contact value by adjusting the length of contact with the determination terminal 133.

The detection plate 135 is a single plate for interlocking with the holder shaft 120 for operating the adjustment bolt 134, and for moving the adjustment bolt 134 up and down by moving the holder shaft 120 up and down. By the vertical movement of 134, the tip of the measuring terminal 133 can be further pressed. In addition, dial gauge 140
Is attached between the measuring terminal 133 and the holder arm 121. The attachment plate 136 fixes the dial gauge 140 to the holder arm 121.
The detection plate 135 fixed to 20 can be moved up and down.

By incorporating such an automatic polishing measurement device N, an adjustment knob 132 of the dial gauge 140 is provided.
At the stage where the machining has progressed to the value set by the adjustment bolt 134, a signal indicating the end of machining is issued, and the machining ends.

[0011]

In general, when controlling the thickness of a lens with high accuracy or obtaining sufficient surface accuracy, it is generally necessary to adjust the spherical axis of the polishing dish, the rotation axis of the spindle and the oscillation axis of the spindle. It is known that if the position of the intersection with the spherical center of the device does not coincide, accurate shape transfer cannot be performed and it is difficult to obtain desired accuracy. In the apparatus described in JP-A-4-4094, a contact-type measuring device such as a dial gauge is provided to perform processing while measuring the thickness of the lens being processed. If a ball center shift or the like occurs, an accurate value cannot be detected. Among them, the spherical misalignment is also caused by a change in the height of the polishing plate due to a change in the temperature of the processing liquid due to a thermal expansion.

Although a relatively stable medium size can be obtained during continuous processing, the medium size often does not reach a desired value after the start-up or break of the apparatus. This is because the length of the polishing holder changes due to the liquid being applied to the polishing holder on the work shaft side, which appears as an error. Therefore, the medium size determined by this mechanism is only a guide, and in reality, the medium size is often controlled by controlling the pressing force, the processing time, and the swing angle.

In the apparatus described in Japanese Patent Application Laid-Open No. 4-4094, the height of the polishing plate varies greatly depending on the radius of curvature (hereinafter referred to as "generating radius") of the lens to be newly polished. The polishing plate for processing the concave surface has a problem that it is easily affected by a temperature change because the distance from the spindle is long.

The present invention has been made in view of such conventional problems. When a lens is subjected to spherical copying and polishing with high precision, the shape is transferred accurately and the medium thickness accuracy and surface accuracy are reduced. It is an object of the present invention to provide a method and an apparatus which can be improved and can obtain stable processing accuracy even during small lot processing or mass production.

[0015]

According to a first aspect of the present invention, there is provided a method for polishing a spherical surface by grinding, comprising: rotating a polishing plate for polishing a spherical surface of an object to be polished while rotating; In a spherical copying grinding method for polishing a spherical surface of the object to be polished by pressing the object to be polished in the direction of the center of gravity of the polishing plate while rotatably holding the object to be polished while supplying a processing liquid to the polishing surface of the plate, The temperature of the working fluid is controlled.

According to the present invention, the working fluid used for grinding and polishing the spherical surface of the object to be polished is kept at a constant temperature, thereby controlling the fluctuation of the height of the polishing plate during the polishing. In particular,
By setting the temperature of the working fluid near room temperature, the correlation with the external setup is increased. Furthermore, stable processing accuracy can be obtained from immediately after the start of production to the end of production.

According to a second aspect of the present invention, there is provided a spherical copying / polishing apparatus for polishing a spherical surface of an object to be polished, rotating means for holding and rotating the polishing dish, and holding means for rotatably holding the rotating means. Oscillating means for oscillating the polishing dish; machining fluid supply means for supplying a machining fluid to the polishing surface of the polishing dish; and a spherical direction of the polishing dish while rotatably holding the object to be polished. And a control means for controlling the temperature of the working fluid.

According to the present invention, the spherical surface of the object to be polished is polished by using the processing liquid whose temperature is kept constant by the control means, so that the fluctuation of the height of the polishing plate during polishing can be controlled, and the processing accuracy can be stabilized. Processing can be performed.

According to a third aspect of the present invention, there is provided a method for polishing a spherical surface according to the first aspect of the present invention, wherein a working fluid whose temperature is controlled is circulated through the entire apparatus to polish a spherical surface of a workpiece. Features.

According to the present invention, not only is the grinding fluid used to grind and grind the spherical surface of the object to be polished using the machining fluid maintained at a constant temperature, but also the machining fluid is circulated throughout the spherical copying and grinding apparatus.
The temperature of the entire apparatus becomes constant, and a more stable ball center position can be obtained.

According to a fourth aspect of the present invention, there is provided a spherical scanning grinding and polishing apparatus according to the second aspect, further comprising a circulating means for circulating a temperature-controlled working fluid throughout the spherical scanning grinding and polishing apparatus. And

In the present invention, in addition to the invention of claim 2,
Since the working fluid whose temperature is controlled by the circulating means is circulated throughout the spherical copying grinding and polishing apparatus, the temperature of the entire apparatus becomes constant and a more stable spherical center position can be obtained.

According to a fifth aspect of the present invention, there is provided a spherical scanning grinding and polishing apparatus according to the second or fourth aspect, further comprising moving means for moving the holding means forward and backward in the direction of the spherical center of the polishing plate. Features.

According to the present invention, the height of the polishing dish can be adjusted together with the holding means for rotatably holding the rotating means, so that the height adjustment of the polishing dish becomes easy.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments. Note that, in the embodiment, only the lower shaft center oscillating polishing method will be described. However, the present invention can be widely applied to other methods, and similar effects can be obtained with a similar configuration.

[First Embodiment] FIGS. 1 to 3 show a first embodiment of the present invention. FIG. 1 is a perspective view of a spherical copying and polishing apparatus, FIG. 2 is a sectional view of a main part of FIG. FIG. 3 is a diagram showing the path of a machining fluid.

1 and 2, a lens 1 as an object to be polished is adhered to a lens holder 2. The lens holder 2 is held by an upper shaft jig 3 so as to be rotatable about a grinding wheel axis A. At a position facing the lens 1, a polishing plate tip 4 a having a spherical surface 4 d (a concave spherical surface in FIG. 2) that matches the lens spherical surface 1 a (a convex spherical surface in FIG. 2) is attached.
b, which are connected to the spindle shaft 5 and these spherical surfaces 4
The polishing plate 4 is composed of the polishing plate tip 4a including the d and the polishing plate base 4b.

The spindle shaft 5 is a rotating means for rotating the polishing plate 4, and includes two or more bearings 5b and spacers 6.
And the fastener 7 so as to be rotatable about the grinding wheel axis A. Further, the spindle shaft 5 is connected to a spindle motor 12 via a pulley 8, a belt 9, and a pulley 10. The spindle motor 12 is fixed to an outer surface of a housing 13 as a holding means by a mounting member 11, and a bearing 5b is also fixed to an inner surface of the housing 13.

A collecting tank 14 having a shape of a collecting tank is fixed to an upper portion of the housing 13, and the collecting tank 14 is provided with a drain port 14a. Here, holes 5a and 4c pass through the center of the spindle shaft 5 and the center of the polishing plate 4, respectively. In addition, a water supply port 1 for processing fluid supply, which can freely change the supply direction, is provided near the tip 4a of the polishing dish.
5 are installed. A water supply circuit (not shown) is connected to the hole 5 a of the spindle shaft 5 and the water supply port 15.

The housing 13 is fixed on a swing base 16 as swing means, and the swing base 16 is rotatably held about a swing axis B by a swing bearing 17. An arc rack 18 is attached to the swing base 16 and meshes with a gear 19. The gear 19 is attached to an output shaft of the motor 20.

The upper shaft jig 3 is attached to a pressing base 22 by an attaching member 21. The pressing base 22 is formed by one or more linear guide blocks 22a and a rail 27a on the slide base 27 side. Guided in the direction.
A pressure plate 24 is attached to the pressure base 22,
The pressure plate 24 is attached to an output shaft of a cylinder 25 as a pressure means. The cylinder 25 is fixed to a slide base 27 by a bracket 26. Pressure base 2
In order to detect the amount of displacement of the second slide base 27 with respect to the slide base 27, the displacement indicator 39
8 is attached facing the slide base 27.

The slide base 27 is fixed to a slide plate 28, and the slide plate 28 is guided in the direction of the grinding wheel axis A by one or more linear guide blocks 28a and rails 29. The protrusion 28 b of the slide plate is screwed to a screw 30, and the screw 30 is connected to a motor 32 via a coupling 31. Motor 32 and rail 29
Is fixed to an apparatus main body (not shown) directly or via a member.

As shown in FIG. 3, the circulation path of the working fluid is
A water tank 33, a pump 34 as a processing liquid supply unit, and a temperature controller 35 as a temperature control unit are provided. The pump 34 is divided into two systems, a center water supply 40 and a recovery tank water supply 41, and is connected to the center hole 5a of the spindle shaft 5 and the water inlet 15 via water control valves 36 and 37, respectively. Here, one water control valve may be provided before dividing the water supply path instead of the water control valves 36 and 37.

In the above configuration, at the time of processing, first, the lens holder 2 to which the lens 1 is attached is supplied to the upper shaft jig 3 manually or by an automatic supply device (not shown).
The rotation of the motor 32 is transmitted to the screw 30 via the coupling 31 in response to a processing start command. By the rotation of the screw 30, the slide plate 28 is guided by the linear motion guide block 28a and the rail 29 and descends along the grinding wheel axis A, and stops at a predetermined position. At this time, the lens 1 and the tip 4a of the polishing dish are kept in contact with the cylinder 25, the linear guide block 22a and the rail 27a at a desired pressure.

A desired shape for polishing is formed at the tip 4a of the polishing dish, and the spherical center of the formed shape (ie, the spherical center of the spherical surface 4d of the polishing dish) is positioned at the spherical center position D ( That is, the height of the polishing plate base 4b is adjusted so as to coincide with the intersection of the grinding wheel axis A and the swing axis).

The polishing plate base 4b is fixed to a spindle shaft 5, and the spindle shaft 5 is rotatably held by a bearing 5b. The rotation of the motor 12 is transmitted, and the polishing plate 4 rotates at a desired rotation speed.

As the polishing plate 4 rotates, the motor 2
0 starts driving, the driving force rotates the gear 19 at a predetermined rotation speed, and reverses the rotation direction of the motor 20 at a predetermined angle. Oscillating motion about the oscillating axis B by the restraining force.

During processing, a processing liquid whose temperature is controlled is supplied through a water supply port 15 and a center hole 5a of the spindle 5, and a housing 13 is provided with a recovery tank 14 for recovering the processing liquid. FIG. 3 from drain 14a
Is returned to the water tank 33 shown in FIG. At this time, the working fluid is stored in the water tank 33 and is maintained at a desired temperature by the temperature controller 35. The processing fluid is pushed out to the hole 5a of the spindle shaft 5 and the water supply port 15 by the pump 34, and the flow rate is adjusted by the respective water control valves 36 and 37 to be supplied to the processing site.

Since the lens 1 is rotatably held by the upper shaft jig 3, the processing proceeds while rotating with respect to the polishing dish tip 4a. When the processing proceeds and the lens 1 is ground and polished by a desired amount, the motor 32 and the coupling 3
The upper jig 3 is moved up along the grinding wheel axis A by the action of the screw 1, screw 30, and the projecting portion 28b of the slide plate 28, and the machining is completed. At this time, the end of machining may be controlled by time, or the actual machining amount may be grasped and controlled by a detector combining the displacement reader 38 and the displacement indicator 39, and in the latter case, accurate machining may be performed. Can be detected.

It is desirable to keep the temperature-controlled machining fluid circulated even after the machining is completed in order to keep the height of the polishing dish 4 constant, and it is preferable that the spindle shaft 5 is also rotated at a low speed. More desirably, the processing liquid supplied from 15 can be received from the entire circumferential direction of the polishing plate 4. The working fluid temperature is preferably maintained at room temperature, but may be set at a temperature between room temperature and about 5 degrees higher than room temperature.

According to such an embodiment, by controlling the temperature of the processing liquid during processing to a constant temperature, the height of the polishing plate 4 does not fluctuate due to the temperature fluctuation, and the spherical center of the polishing plate 4 The position can be kept constant. Therefore, the polishing plate 4
The error caused by the disagreement of the intersection of the grinding wheel axis A and the swing axis B, which are the ball center of the apparatus and the ball center of the apparatus, can be suppressed, the transfer of the surface shape can be improved, and the surface accuracy can be improved. In addition, since the reference position for processing is stable, the accuracy of the dimension of the medium thickness is improved.

Further, since the temperature of the working fluid is kept constant, the fluctuation of the grinding and polishing force due to the temperature is suppressed, so that the improvement of the dimensional accuracy of the medium thickness has a sufficient effect even in the processing by time control. . Displacement reader 38 and displacement indicator 39
When the combination is used, the effect of stabilizing the ball center position is further increased, so that the accuracy of the medium thickness is more stabilized.

If the temperature of the working fluid is set to room temperature, the height of the polishing dish 4 may change due to the temperature difference even when the polishing dish 4 is mounted on an apparatus after the height of the polishing dish 4 is determined by external setup. Disappears. Therefore, in addition to the above effects, there is also an effect that the position of the ball center is accurately determined.

Further, since stable processing can be performed during continuous processing or immediately after the start of processing, a wide range from small lots to mass production can be handled.

In this embodiment, the processing fluid is supplied from the center hole 5a of the spindle shaft 5 and the water supply port 15, but the supply of the processing liquid from the water supply port 15 alone has a sufficient effect. .

[Second Embodiment] FIG. 4 shows the path of the working fluid according to the second embodiment of the present invention. Embodiment 1 outlines the device
4 and the description thereof will be omitted in FIG.

As shown in FIG. 4, in this embodiment, in addition to the structure of the first embodiment, an apparatus circulation path 42 as circulation means is provided. The apparatus circulation path 42 circulates the working fluid throughout the apparatus. As a result, the processing liquid sent from the pump 34 is supplied from the center hole 5a of the spindle shaft 5 and the water supply port 15 to the lens 1 as in the first embodiment.
In addition, the processing liquid whose temperature is controlled is circulated through the apparatus circulation path 42 to the entire processing apparatus.

According to this embodiment, in addition to the same effects as those of the first embodiment, the effect of controlling the temperature of the working fluid is exerted on the entire apparatus, so that a more stable spherical center position can be obtained.

Third Embodiment A third embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG. 5 is a perspective view of a spherical copying and polishing apparatus, and FIG. 6 is a sectional view of a main part of FIG. is there. The same parts as in the first embodiment are denoted by the same reference numerals,
Description is omitted.

As shown in FIG. 5 and FIG. 6, in addition to the structure of the first embodiment,
The swing base 16 is provided with a rail 16a which engages with the swing base 3a. In addition to the linear motion guide block 13a, the housing 13 is provided with a protrusion 13b, and a screw 44 is screwed to the protrusion 13b.
The screw 44 is connected via a coupling 45 to a motor 46 as moving means fixed to the swing base 16.

The operation involved in processing with this configuration is basically the same as that of the first embodiment, but by moving the entire spindle mechanism, the polishing plate base 4b
It is possible to make the center of the spherical surface 4d of the polishing dish coincide with the intersection D between the grinding wheel axis A and the swing axis B, which is the center of the apparatus, even if the generation R changes without changing the diameter. The mechanism is such that the height of the polishing plate 4 is kept constant irrespective of the generation R, and the housing 13 is connected to the linear motion guide block 13a and the rail 16a.
, And driven by a motor 46 via a screw 44 and a coupling 45, the spherical center position of the polishing dish spherical surface 4b can be matched with the spherical center position of the apparatus.

According to this embodiment, the same effect as in the first embodiment can be obtained, and in addition, the spherical center position of the polishing plate spherical surface 4b can be constantly corrected even when the height of the polishing plate 4 varies. In addition, the external setup is facilitated, and the effect of the temperature is not changed by the generating radius.

[0053]

According to the first and second aspects of the present invention,
By controlling and maintaining the temperature of the working fluid to be constant, the position of the spherical center can be stabilized, so that the shape transferability is improved and the surface accuracy is improved. Further, since the spherical center position, which is the reference position, is stabilized and the grinding and polishing amount is stabilized, the dimensional accuracy of the medium thickness is also improved.

According to the third and fourth aspects of the present invention, in addition to the above-mentioned effects, the effect of controlling the temperature of the working fluid is exerted on the entire apparatus, so that a more stable ball center position can be obtained.

According to the fifth aspect of the present invention, in addition to the above effects, the center of the polishing plate and the center of the apparatus can be easily matched with each other, so that the setup is facilitated and even if the creation radius differs. There is no difference due to temperature fluctuation.

[Brief description of the drawings]

FIG. 1 is a perspective view of a spherical copying grinding and polishing apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of FIG.

FIG. 3 is a circuit diagram of a working fluid circulation circuit according to the first embodiment.

FIG. 4 is a working fluid circulation circuit diagram of the spherical copying grinding and polishing apparatus according to the second embodiment.

FIG. 5 is a perspective view of a spherical copying grinding and polishing apparatus according to a third embodiment.

FIG. 6 is a sectional view of a main part of FIG. 5;

FIG. 7 is a sectional view of a main part of a conventional spherical scanning grinding and polishing apparatus.

[Explanation of symbols]

 4 Polishing Dish 5 Spindle Shaft 13 Housing 16 Swing Base 25 Cylinder 34 Pump 35 Temperature Controller

Claims (5)

[Claims] 1. A polishing plate for polishing a spherical surface of an object to be polished is rotated while being rotated, and a polishing liquid is supplied to a polishing surface of the polishing plate while the object to be polished is held rotatably. A spherical copying grinding and polishing method for polishing a spherical surface of an object to be polished by applying pressure in a spherical center direction, wherein the temperature of the working fluid is controlled. 2. A polishing dish for polishing a spherical surface of an object to be polished, rotating means for holding and rotating the polishing dish, holding means for rotatably holding the rotating means, and a rocking means for rocking the polishing dish. Moving means, a working fluid supply means for supplying a working liquid to the polishing surface of the polishing dish, and a pressurizing means for pressurizing in the direction of the ball center of the polishing dish while rotatably holding the object to be polished. In the profile grinding and polishing apparatus, a control means for controlling the temperature of the working liquid is provided. 3. The method according to claim 1, further comprising: circulating a temperature-controlled working fluid throughout the apparatus to polish a spherical surface of the object to be polished. 4. The spherical copying and grinding apparatus according to claim 2, further comprising a circulating means for circulating a temperature-controlled working fluid throughout the spherical copying apparatus. 5. The spherical scanning grinding and polishing apparatus according to claim 2, further comprising moving means for moving the holding means forward and backward in the direction of the spherical center of the polishing plate. .