JPH11156688A - Lens centering clamp device, and lens centering and edging machine using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce sliding resistance of a bell holder in a centering process. SOLUTION: A lens is attracted to a fixing side bell holder land is temporarily held, a moving side bell holder 2 is moved to the fixing side bell holder 1, lens contacting parts 1a, 2a of the both bell holders 1, 2 are pressed onto the lens to center the lens. By previously specular-finishing the lens contacting parts 1a, 2a of the bell holders 1, 2 to surface roughness les than Rmax1 μm with a bell holder grinding/polishing unit 6, sliding resistance of the lens contacting parts 1a, 2a is reduced, and a time taken for lens centering is shortened. This helps to reduce abrasion of the bell holders 1, 2 and improve their durability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens centering clamp device used for a lens centering machine for grinding an outer diameter portion of a lens as an optical element for centering, and a lens centering device using the same. It is about the machine.

[0002]

2. Description of the Related Art A lens centering machine for grinding an outer diameter portion of a lens as an optical element to perform so-called centering includes a lens clamp mechanism for holding a lens and rotating the lens around an optical axis, and a rotating lens. It has a grinding device such as a grindstone that abuts a grindstone on the outer circumference of the lens, and the lens clamp mechanism has a so-called centering function to match the optical axis and the rotation axis of the lens in the process of clamping the lens. A lens centering clamp device provided is often used.

FIG. 14 shows a lens centering mechanism according to a conventional example disclosed in Japanese Patent Application Laid-Open No. 58-160051, in which a lens R ₀ is attached to a fixed bell holder (lower cup body) 101 facing upward in the figure. Is temporarily held by suction, and is lowered while rotating the movable-side bell holder (upper cup body) 102, and the lens R held by the fixed-side bell holder 101 is rotated.
₀ , and the lens R ₀ is held between the fixed-side bell holder 101 and the movable-side bell holder 102. In the process of clamping the lens R _{0 in} this manner, as shown in FIG.
Using the tangential forces like acting on the contact point of the lens contact portion 102a and the lens R ₀ of the movable Beruhoruda 102, a lens contact portion 101a, 102 of each Beruhoruda 101
The centering is performed by sliding the lens _R0 with respect to a.

The fixed-side bell holder 101 has a hollow portion 111.
The spindle 111 is integrally connected with a spindle 111 having a. The spindle 111 is rotatably supported by a bearing 112. The hollow portion 111a of the spindle 111 is connected to a vacuum source (not shown) by a nipple 111b, and a lens R is attached to the lens contact portion 101a of the fixed-side bell holder 101.
A vacuum suction force for sucking ₀ is generated. The movable bell holder 102 is integrally connected to one end of a spindle 121, and the spindle 121 is
It is rotatably supported by.

A rotation drive unit 103 for rotating the bell holders 101 and 102 includes a rotation shaft 131 and gear trains 132 and 133 for transmitting the rotation of the drive shaft 130 a of the motor 130 to the spindle 111 of the fixed-side bell holder 101. Gear trains 134, 1 for transmitting the rotation of the drive shaft 130a to the spindle 121 of the movable-side bell holder 102
The drive shaft 130a and the rotary shaft 131 are connected via a one-way clutch 136.

[0006] The one-way clutch 136 is used by the motor 130 in the lens centering step of grinding the outer diameter of the lens _R0.
Is rotated forward, the rotation is transmitted to both spindles 11
Transmitted to 1,121, it rotated with respect to the grindstone for outer diameter grinding an unillustrated lens R ₀ which is sandwiched between the two Beruhoruda 101.

In the lens centering step of holding the lens R ₀ between the bell holders 101 and 102, the motor 130 is rotated in the reverse direction, and the rotation is
Is transmitted only to the spindle 121 of the movable Beruhoruda 102 through 4,135, movable Beruhoruda 102 to the lens R _0, which is temporarily held on the fixed side Beruhoruda 101
Are relatively rotated, and the eccentricity is corrected by sliding the lens R ₀ as described above.

An axial drive unit 104 for moving the movable bell holder 102 in the axial direction includes a pin-on-rack mechanism 143 to a cylinder 141 and a pin-on-rack mechanism 143 to transmit a linear movement of a piston 142 of the cylinder 141 to a bearing 122 of the movable bell holder 102. 145 etc.

In such a lens centering clamp device, it is disclosed in the optical element processing technology '92 and the like issued by the Japan Opto-Mechatronics Association that brass is suitable as a material for both bell holders. As a structure in which a mounting portion of a bell holder is improved, Japanese Patent Laid-Open No.
What is described in 61231 is excellent.

[0010]

However, according to the above prior art, in the lens centering step of centering the lens by sliding the lens with respect to the lens abutting portions of both bell holders, the lens abutment of the bell holder is performed. There is an unsolved problem that the time spent for centering is long because the sliding resistance of the portion is large, thereby reducing the throughput of the device.

In addition, if the sliding resistance of the bell holder is large, the bell holder is seriously damaged due to the centering of the lens, and it is necessary to perform a repair work such as periodically polishing the lens contact portion of the bell holder. The process of attaching and detaching to and from the spindle is complicated, and when attaching the bell holder to the spindle, it is also necessary to adjust the coaxiality of the bell holder and the spindle. The result is a significant loss of availability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and a lens holder of each bell holder is mirror-finished so as to reduce sliding resistance to the lens. To provide a lens centering clamp device and a lens centering machine using the same, which can improve the durability of the lens, shorten the time spent centering the lens, and greatly improve the accuracy and the operating rate of the lens centering machine. It is intended for.

[0013]

In order to achieve the above object, a lens centering and clamping apparatus according to the present invention comprises a pair of bell holders which can be freely moved toward and away from each other in an axial direction on a support base, and at least one bell holder. It has an axial driving unit that moves in the axial direction, and a rotation driving unit that can rotate the pair of bell holders individually, and the lens contacting part of each bell holder is attached to the lens in the process of holding the lens by both bell holders. A lens centering clamp device configured to center the lens by pressing, wherein the lens contacting portion of each bell holder has a surface roughness R.
It is characterized in that it is mirror-finished to a maximum of 1 μm or less.

It is preferable that the annular edge portion of the lens contact portion of each bell holder is rounded with a radius of curvature of 1 mm or more.

Also, a pair of bell holders which can be freely moved toward and away from each other in the axial direction on the support base, an axial driving unit which moves at least one of the bell holders in the axial direction, and the pair of bell holders which can be individually driven to rotate. It may have a rotation drive unit, a bell holder polishing means for mirroring the lens contact part of each bell holder, and an attachment means for detachably attaching the bell holder polishing means to the support table.

It is preferable that the bell holder polishing means is configured so that a cutting tool for determining the inner diameter of the lens contact portion of each bell holder can be freely attached.

Further, it is preferable that the bell holder polishing means is configured so that a round bit for rounding an annular edge portion of a lens contact portion of each bell holder to a radius of curvature of 1 mm or more can be freely attached.

[0018]

When the lens contact portion of the bell holder is pressed against the lens in the process of holding the lens between the pair of bell holders and the lens is centered, if the sliding resistance of the lens contact portion of the bell holder is large, the lens is centered. The required time is long, which reduces the operating rate of the lens centering machine. Further, the bell holder is significantly worn or damaged due to the centering of the lens, and the durability of the bell holder is low.

Therefore, a bell holder polishing means is configured to be freely attachable to the support base of the lens centering machine, and the lens contact portion of the bell holder is mirror-finished in advance to a surface roughness Rmax of 1 μm or less by the bell holder polishing means, and the sliding resistance to the lens is reduced. In addition, the ring edge of the lens abutment part of the bell holder is rounded to a radius of curvature of 1 mm or more to prevent the lens from being scratched in the centering process, so that it is quick and stable. Alignment can be performed.

Before the step of mirror-fining the lens contact portion of the bell holder, a step of setting the inner diameter of the bell holder by a grinding tool may be added.

After the bell holder is polished and detached from the support table, operations such as inner diameter setting of the bell holder, mirror finishing, and rounding are sequentially performed, and the lens is centered through the lens centering according to a preset program. A lens centering cycle for outer diameter centering or centering is started.

By reducing the sliding resistance of the bell holder with respect to the lens, the time required for the centering step by the bell holder can be shortened, and the durability of the bell holder can be greatly improved. In addition, the operation rate of the lens centering machine can be significantly improved by consistently performing mirroring and the like from the inner diameter of the bell holder on the lens centering machine.

[0023]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a main part of a lens centering clamp device and a lens centering machine according to an embodiment, and a lens R ₁ (see FIG. 2) is attached to a fixed side bell holder 1 on the left side in the drawing. ) Is adsorbed and temporarily held, and the movable bell holder 2 is moved to the left while being rotated, and is pressed against the lens R ₁ held by the fixed bell holder 1, so that the fixed bell holder 1 and the movable bell holder 2 In the process of sandwiching the lens R ₁ between the lens abutment portions 2 of the movable-side bell holder 2
using the tangential forces like acting on the contact point of a lens R _1, configured to perform centering by sliding the lens R ₁ with respect to the lens contact portion 1a, 2a of each Beruhoruda 1,2 Have been.

As shown in FIG. 2, the fixed-side bell holder 1
Is integrally connected to a spindle 11 having a hollow portion 11a, and the spindle 11 is rotatably supported by a bearing 12. Hollow portion 11a of the spindle 11 is connected to a vacuum source (not shown) by a nipple 11b, and the lens R ₁ to generate vacuum suction force for sucking the lens contact portion 1a of the fixed Beruhoruda 1. The movable-side bell holder 2 is integrally connected to one end of a spindle 21, and the spindle 21 is rotatably supported by a bearing 22.

A first rotation drive unit 3 for rotating the bell holders 1 and 2 includes a rotation shaft 32 and gear trains 33 and 34 for transmitting the rotation of the drive shaft 31 of the motor 30 to the spindle 11 of the fixed bell holder 1. There are gear trains 35 and 36 for transmitting the rotation of the drive shaft 31 of the motor 30 to the spindle 21 of the movable bell holder 2, and the rotation shaft 32 and the drive shaft 31 are connected via a one-way clutch 37.

In the lens centering step of grinding the outer diameter of the lens R ₁ , the one-way clutch 37 controls the rotation of both spindles 11 and 21 when the motor 30 rotates forward.
Is transmitted to the lens R ₁ which is sandwiched between the two Beruhoruda 1,2 but rotated with respect to the grinding wheel 10 is a grinding means shown in Figure 1, the process for clamping the lens R ₁ both Beruhoruda 1,2 In the lens centering step, the motor 30 is rotated in the reverse direction, and the rotation is transmitted only to the spindle 21 of the movable-side bell holder 2, and the movable-side bell holder 2 is moved to the lens R ₁ temporarily held by the fixed-side bell holder ₁ . rotated relative to correct the eccentricity slide the lens R ₁ as described above.

An axial drive unit 4 for moving the movable-side bell holder 2 in the axial direction includes a cylinder 41 and a linear movement of a piston 42 of the cylinder 41 for linearly moving the bearing 2 of the movable-side bell holder 2.
2 and a pin-on-rack mechanism 43 to 45 for transmitting the power to the power transmitting device 2.

As described above, the first rotation drive unit 3 performs the step of centering the lens R ₁ temporarily held by the fixed-side bell holder 1, and the step of centering the lens R ₁ held by the fixed-side bell holder 1 and the movable-side bell holder 2. ₁ is used in a centering step of grinding the outer diameter portion with a grindstone 10 and the like.
The rotation of 0 is transmitted to the drive shaft 31 via the electromagnetic clutch 30a.

The driving unit of the grinding wheel 10 includes a feed direction slider 10a, an axial slider 10b, and a grinding wheel rotating unit 10 arranged on the upper surface of the base 5 which is a support for the lens centering machine.
c and the like, and the grindstone rotating unit 10c includes a belt drive unit 10f and the like for transmitting the rotation of the motor 10d to the spindle 10e of the grindstone 10.

The base 5 has a notch 51 for mounting a bell holder grinding and polishing unit 6 as a bell holder polishing means shown in FIG. 1B with screws or the like as mounting means. , 21 for rotating, a rotating shaft 32, a gear train 33-
36 and the like are built in the base 5.

The bell holder grinding and polishing unit 6 includes a lens contact portion 1 of the fixed side bell holder 1 and the movable side bell holder 2.
It is used in the step of grinding and polishing a and 2a, and is configured to be detachable from the notch 51 of the base 5.

In the above-described lens centering process, if the lens contact portions 1a and 2a of the bell holders 1 and 2 have eccentricity, etc., accurate centering cannot be performed. lens contact portion 1a, 2a of the sliding resistance when the lens R ₁ slid by pressing the lens R ₁ is greater takes time centering, in addition, the lens contact portion 1a of the Beruhoruda 1,2 , 2a are easily damaged. Furthermore, resulting in troubles such as lens R ₁ being damaged by the lens leading edge of the contact portion 1a, 2a. Therefore, with the bell holders 1 and 21 attached to the spindles 11 and 21, the lens contact portions 1 a and 2 a of the bell holders 1 and 2 are ground and polished by the bell holder grinding and polishing unit 6.
The inner diameter of the lens contact portions 1a and 2a and the surface roughness R
There is provided a step of performing mirror finishing with a maximum of 1 μm or less.

When the lens contact portions 1a and 2a of the bell holders 1 and 2 are ground and polished as described above, the electromagnetic clutch 30a of the first rotary drive unit 3 is turned off, and each of the bell holders 1 and 2 is moved to the first position. It is rotated by the second rotation drive unit 7.

As shown in FIG. 2, the second rotary drive 7
Has a motor 70, a gear train for transmitting the rotation of the motor 70 to the rotating shaft 32, and a second electromagnetic clutch 70a. As described above, the first electromagnetic clutch 30a is turned off, and the second electromagnetic clutch 70a Is turned ON, and the bell holder grinding and polishing unit 6 performs grinding and polishing while rotating each of the bell holders 1 and 2 by the second rotation drive unit 7.

As shown in FIG. 3, the bell holder grinding and polishing unit 6 includes a support 61 fixed to a cutout portion 51 of the base 5 by screws or the like, a feed direction slider 62 supported by the support 61, and The mounted axial slider 6
3 and a tool holder 64 and the like provided on the upper surface of the axial slider 63. The tool holder 64 includes a cutting tool 65 having a cutting edge 65a such as a carbide, diamond, or CBN for obtaining the inner diameter of each of the bell holders 1 and 2, and the lens contact portions 1a and 2a of each of the bell holders 1 and 2. Air grinder 66 having grinding wheel 66a for polishing for mirror finishing
(See FIG. 4) and the lens contact portion 1 of each of the bell holders 1 and 2.
A round tool 67 (see FIG. 5) on which a diamond sheet 67a for so-called rounding for removing burrs or the like by rounding (R) the ends of a and 2a can be attached.

The lens contact portions 1a of the bell holders 1 and 2
The step of setting the inner diameter of 2a by the bell holder grinding / polishing unit 6 to make it mirror-finished is performed as follows. First,
The bell holder grinding and polishing unit 6 with a grinding tool 65 attached thereto is mounted in the cutout 51 of the base 5 and the second
By rotating the two bell holders 1 and 2 by the rotary drive unit 7, the position and feed of the cutting edge 65a of the cutting tool 65 for grinding are adjusted, and the inner diameters of the lens contact portions 1a and 2a are determined. The tool holder 65 is replaced with an air grinder 66, and both bell holders 1 and 2 are rotated in the same manner as described above, so that each lens contact portion 1a, 2a is made to have a surface roughness Rmax1.
The surface is mirror-finished to μm or less (see FIG. 7A).

Next, the air grinder 66 is replaced with a round tool 67, and both bell holders 1 and 2 are moved in the same manner as described above.
2 is rotated to remove burrs and the like at the annular edges of the lens contact portions 1a and 2a as shown in FIG. 7 (b), and to perform rounding with a radius of curvature of 1 mm or more. In this step, as shown in FIG. 6, without using the round tool 67, the diamond contact 68 is manually held and the lens contact portions 1a and 2 of the rotating bell holders 1 and 2 are rotated.
a.

If the centering of the lens is performed using the bell holder that has been finished with the inner diameter and the mirror surface and the rounded surface as described above, the sliding resistance when the lens is slid with respect to the lens contact portion of the bell holder is reduced. Because of its small size, the time spent in the centering process can be reduced, and the accuracy of centering can be greatly improved. Furthermore, since the bell holder is less likely to be damaged in the centering step, the durability of the bell holder is improved.

By using a bell holder grinding and polishing unit that is detachable from the base of the lens centering machine, the inner diameter of the bell holder, mirror finishing, and all the steps of centering and centering the lens are continuously performed. However, there is a remarkable advantage that the operation rate of the lens centering machine can be greatly improved.

In addition, even if burrs or the like are generated at the tip of the lens abutment portion of the bell holder in the above-described grinding and polishing steps, the burrs are completely removed in the final rounding step, so that the burrs and the like cause Since the centering operation of the lens is not hindered and there is no possibility that the lens is damaged due to the burr of the bell holder, the centering can be performed stably and quickly.

As described above, since there is no possibility of damaging both the bell holder and the lens, it is possible to use a metal having a higher hardness or a plastic material having a smaller coefficient of friction as the material of the bell holder. For example, conventionally, in order to prevent the lens from being damaged in the centering process using the bell holder, it is common to use brass having a Vickers hardness of about 110 and a static friction coefficient of 0.14 to 0.16 as the material of the bell holder. However, according to the present embodiment, for example, in the case of a relatively hard lens, carbon tool steel, alloy tool steel, prehardened steel, or the like having a Vickers hardness of 200 or more can be used. As described above, by making the material of the bell holder harder, the durability of the bell holder can be improved four to five times.

Conversely, in the case of a relatively soft lens, the durability of the bell holder can be improved about four times by using a polyacetal resin, polyamide, polyimide resin or the like having a static friction coefficient of 0.13 or less. it can.

(First Embodiment) As shown in the table, the Vickers hardness of a general optical lens has a range of 400 to 850 depending on the type of glass. A glass type having a Vickers hardness of 850 is tentatively called a hard glass type lens, and a glass type having a Vickers hardness of 400 is tentatively called a soft glass type lens.

[0045]

[Table 1] In the centering step of grinding the outer diameter portion of the lens by clamping and holding the concave hard glass type lens with a bell holder, the temporary holding state of the hard glass type lens by the fixed side bell holder of the conventional lens centering machine is shown in FIG. As shown. The material of the two bell holders for clamping and holding the lens is brass, and the Vickers hardness of the brass is about 110 as described above. As shown in FIG. 9B, the lens is easily scratched by the edge of the lens abutting portion, and the centering takes a long time because the sliding resistance of the lens abutting portion is large.

The temporary holding state of the hard glass type lens using the bell holder shown in FIG. 7 is as shown in FIG. As a material of the bell holder for holding the lens by clamping, carbon tool steel, alloy tool steel, pre-hardened steel or the like having a Vickers hardness of 200 or more is used. Alternatively, another steel material having a Vickers hardness of 200 or more by heat treatment or the like is used.

The selection of a material having a Vickers hardness of 200 or more depends on the hardness of the lens glass material, the removal volume of the lens, the removal speed,
This is performed based on the lens holding power, lens diameter, lens shape, and the like.

As described above, by increasing the hardness of the bell holder for holding the lens of the hard glass type lens by clamping, the durability of the lens abutting portion of the bell holder in contact with the lens is increased by 4 to 4.
5 times improvement.

Next, the lens contact portion of the bell holder that comes into contact with the lens is mirror-finished by a bell holder grinding and polishing unit to a surface roughness Rmax of 1 μm or less, thereby reducing the sliding resistance in the process of centering by sliding the lens. As a result, the time required for centering work can be greatly reduced. In addition, the damage to the bell holder was reduced, and the durability was further improved by about 1.5 times.

Further, as shown in FIG. 8 (b), the tip of the edge of the lens contact portion of the bell holder in contact with the lens is rounded to a radius of curvature of 1 mm or more, so that the tip generated by grinding and polishing or the like is formed. The centering action of the lens could be performed stably without being affected by burrs and the like of the portion. Further, the lens contact portion of the bell holder was prevented from being damaged due to the above-mentioned burrs and the like, and the durability of the bell holder could be further improved by about 1.2 times.

FIG. 12 shows an experimental result in which the centering of a concave lens is performed using the lens centering machine of FIG. 1 and the durability of the bell holder is compared with that of the conventional example.

The outer diameter of the lens is φ15 (mm), the coefficient of static friction is 0.1, the Vickers hardness is 847 kgf / mm ² ,
The processing conditions of the lens are as follows: processing time of each lens is 50 seconds, clamping pressure is 40 kg / cm ² , cam control method is adopted, one cycle of rotation of cam (360 degrees), one cycle of outer diameter direction cam 5 m.
Electrodeposited whetstone # 275 / # 325 was used as the grindstone. Sample A was made of brass material made of brass, sample B was made of pre-hardened steel, and sample C was made of a mirror-finished pre-hardened steel bell holder as described above.
As a sample D obtained by performing the above-mentioned mirror finishing and rounding on the lens contact portion of the pre-hardened steel bell holder, and as a sample D, it was examined how many lenses can be processed until the lens is damaged by the bell holder. Sample B
Showed durability 4 to 5 times that of sample A, durability of sample C was about 1.5 times that of sample B, and sample D was about 1.2 times that of sample C.

(Second Embodiment) In a centering step of grinding a convex soft glass lens having a Vickers hardness close to 400 with a bell holder and grinding the outer diameter of the lens,
FIG. 11 shows the temporary holding state of the soft glass type lens by the fixed bell holder of the conventional lens centering machine.
The material of the two bell holders for clamping and holding the lens is brass, and the static friction coefficient of brass is 0.14 to 0.16.

The temporary holding state of the soft glass type lens using the bell holder shown in FIG. 7 is as shown in FIG. 10, and the material of the bell holder for clamping and holding the lens is a plastic material having a static friction coefficient of 0.13 or less. For example, a polyacetal resin, a polyamide, a polyimide resin, or the like is used.

Selection of a plastic material having a static friction coefficient of 0.13 or less depends on the hardness of the lens glass material, the removal volume of the lens,
This is performed based on the removal speed, lens holding power, lens diameter, lens shape, and the like.

As described above, the material of the bell holder for clamping and holding the lens of the soft glass type lens has a static friction coefficient of 0.13.
By using the following materials, the durability of the lens contact portion of the bell holder in contact with the lens could be improved four times.

Next, the lens contact portion of the bell holder that comes into contact with the lens is mirror-finished to a surface roughness Rmax of 1 μm or less by a bell holder grinding and polishing unit, thereby reducing the sliding resistance in the process of centering by sliding the lens. As a result, the time required for centering work can be greatly reduced. In addition, the damage to the bell holder was reduced, and the durability was further improved by about 1.3 times.

Further, as shown in FIG. 10B, the tip of the lens contact portion of the bell holder in contact with the lens is rounded to have a radius of curvature of 1 mm or more, so that burrs at the tip caused by grinding and polishing are obtained. Thus, the centering action of the lens could be performed stably without being affected by such factors. Also, the lens contact portion of the bell holder is prevented from being damaged due to the above-mentioned burrs and the like, and the durability of the bell holder is further reduced by about 1.
It was able to improve twice.

FIG. 13 shows an experimental result of comparing the durability of the bell holder with that of the conventional example by centering a convex lens using the lens centering machine of FIG.

The outer diameter of the lens is φ20 (mm), the coefficient of static friction is 0.09, and the Vickers hardness is 413 kgf / mm.
^2. Lens processing conditions are as follows: processing time of each lens is 60 seconds,
A clamp pressure of 30 kg / cm ² , a cam control method is adopted, one cycle of rotation of the cam (360 degrees), one cycle of the outer diameter direction cam 5 mm / 312 degrees, a lateral feed cam 5 mm / 140 degrees, and a grinding stone # 275 / # 325 was used. The material of the bell holder was made of brass as sample A, the polyimide resin having a friction coefficient of 0.29 as sample B, the polyimide resin having a friction coefficient of 0.12 as sample C, and the bell holder having a polyimide resin friction coefficient of 0.12 as a lens. A mirror-finished contact portion as described above is referred to as Sample D, and a mirror-finished and rounded lens contact portion of a bell holder having a polyimide resin friction coefficient of 0.12 is referred to as Sample E. Investigating how many lenses can be processed before damage occurs in sample C
Shows durability 2 to 4 times that of sample A, durability of sample D is about 1.3 times that of sample C, and sample E is about 1.2 times that of sample D.

[0061]

Since the present invention is configured as described above, it has the following effects.

The lens contact portion of the bell holder is mirror-finished to reduce the sliding resistance to the lens, thereby improving the durability of the bell holder and shortening the time required for centering the lens. Operating rate can be greatly improved.

[Brief description of the drawings]

FIG. 1 shows a lens centering machine according to an embodiment, in which (a) is a partial perspective view showing a main part of the lens centering machine, and (b) is a perspective view showing only a bell holder grinding and polishing unit. .

FIG. 2 is a view showing a driving unit of a bell holder of the apparatus shown in FIG. 1;

FIG. 3 is an enlarged view showing a bell holder grinding and polishing unit.

FIG. 4 is a view showing an air grinder which can be attached to the bell holder grinding and polishing unit of FIG. 3;

FIG. 5 is a view showing a round tool that can be attached to the bell holder grinding and polishing unit of FIG. 3;

FIG. 6 is a view showing a manual operation for rounding the bell holder of the apparatus of FIG. 1;

FIG. 7 is an enlarged view showing a bell holder of the apparatus of FIG. 1;

FIG. 8 is a diagram illustrating a process of centering a concave lens by the bell holder of the first embodiment.

FIG. 9 is a view for explaining a step of centering a concave lens using a bell holder according to a conventional example.

FIG. 10 is a diagram illustrating a process of centering a convex lens by a bell holder according to a second embodiment.

FIG. 11 is a diagram illustrating a process of centering a convex lens using a bell holder according to a conventional example.

FIG. 12 is a graph showing experimental results of the first example.

FIG. 13 is a graph showing experimental results of the second embodiment.

FIG. 14 is a view showing a centering mechanism according to a conventional example.

FIG. 15 is a view illustrating a centering step by the apparatus of FIG. 14;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed-side bell holder 2 Movable-side bell holder 3 1st rotation drive part 4 Axial drive part 5 Base 6 Bell holder grinding and polishing unit 7 2nd rotation drive part 10 Grinding stone 65 bytes 66 Air grinder 67 R-bite 68 Diamond sheet

Claims (6)

[Claims] 1. A pair of bell holders that can be freely moved toward and away from each other in an axial direction on a support base, an axial driving unit that moves at least one of the bell holders in an axial direction, and the pair of bell holders that can be individually driven to rotate. A lens centering clamp device having a rotation drive unit and configured to center the lens by pressing a lens contact part of each bell holder against the lens in a process of holding the lens between the two bell holders. Wherein the lens contact portion of each bell holder is mirror-finished to a surface roughness Rmax of 1 μm or less. 2. The lens centering clamp device according to claim 1, wherein an annular edge portion of the lens contact portion of each bell holder is rounded with a radius of curvature of 1 mm or more. 3. A pair of bell holders that can be freely moved toward and away from each other in an axial direction on a support base, an axial driving unit that moves at least one of the bell holders in an axial direction, and the pair of bell holders that can be individually rotated and driven. A lens centering clamp device comprising: a rotation drive unit; bell holder polishing means for mirroring a lens contact part of each bell holder; and mounting means for detachably mounting the bell holder polishing means to the support table. 4. The lens centering clamp device according to claim 3, wherein the bell holder polishing means is configured to be able to freely attach a cutting tool for setting an inner diameter of a lens contact portion of each bell holder. 5. A bell holder polishing means, wherein a round bit for rounding an annular edge portion of a lens contact portion of each bell holder to a radius of curvature of 1 mm or more is freely attachable. 5. The lens centering clamp device according to 3 or 4. 6. A lens centering machine comprising: the lens centering clamp device according to claim 1; and a grinding means for grinding an outer diameter portion of a lens held by the device.