JPH07266211A - Grinding and polishing wheel - Google Patents

Abstract

PURPOSE:To machine an optical element with high accuracy in the non-blocking grinding and polishing. CONSTITUTION:A grinding wheel 1 is formed of a grinding wheel part 2, which is made of the abrasive grains and the bond material, and a ring band part 3, which is positioned in the periphery of the grinding wheel part 2 and which has the same radius R of curvature as the grinding wheel part 2 and which is made of the material having the same wear rate and longitudinal elastic coefficient as the grinding wheel part 2. In the case where the outer diameter of a lens 33 is represented by D, the radius of curvature is represented by R and the half angle sin<-1> (D/2R) of the lens 33 is represented by thetaL, half angle thetar of the ring band part 3 is 0.25 thetaL or larger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding / polishing grindstone used for non-blocking grinding / polishing by fitting an optical element such as a lens into a holder.

[0002]

2. Description of the Related Art Conventionally, as a grinding / polishing grindstone for an optical element, for example, there is one disclosed in Japanese Patent Laid-Open No. 5-261668. This grinding / polishing grindstone is as shown in FIG. 10, and has abrasive grains 20 such as diamond and boron nitride.
Are mixed and contained in a conductive material 21 having conductivity such as an iron-based material and a nickel-based material, and are formed in a convex shape. In addition, this pellet-shaped grinding / polishing grindstone
The outer peripheral surface 23 other than the polishing surface 22 is covered with a coating coat 24 of a material such as a silicon-based material or a polyimide-based material having a high withstand voltage and a high insulating effect. Such a grinding / polishing grindstone is used for electrolytic dressing grinding, and the coating coat 24 having an excellent withstand voltage prevents electrolysis / oxidation of parts other than the grinding / polishing surface 22, thereby deteriorating the machining size and accuracy of the work and the grindstone strength. (Durability) is prevented from lowering.

Further, the conventional non-blocking grinding / polishing process is performed as shown in FIGS. 11 and 12 by using a holder as disclosed in, for example, Japanese Unexamined Patent Publication No. 2-124256 and Japanese Utility Model Laid-Open No. 2-66944. Has been done in. The holder 30 has a substantially disc-shaped base 32 supported by a rod-shaped knit 31 having a spherical support portion formed at its lower end. The base 32 holds the lens 33, and a ring-shaped receiving member 34 made of an elastic material such as rubber is interposed between the receiving surface 32 a of the base 32 and the receiving surface 33 a on the upper surface of the lens 33. Has been done. In order to grind and polish the lens 33 held by such a holder 30, a grindstone 35 (see FIG.
(See 0) while pressing the grinding / polishing surface 35a, the grindstone 35 is rotated about the axis and is swung about the swing center O.

[0004]

In the above non-blocking grinding / polishing process, when a conventional grinding / polishing grindstone is used, the grindstone 35 rocks at an appropriate angle in order to maintain the lens shape during the process. 11 and 1
As shown in FIG. 2, a non-contact portion 36 where the grindstone 35 and the lens 33 do not contact each other is formed. At this time, the ring-shaped receiving member 34 of the holder 30 is released from the compressive load only in the portion corresponding to the non-contact portion 36 of the lens 33, and a restoring force for returning to the original shape is generated. Due to this restoring force, the lens 33
Will be deformed with the portion protruding from the grindstone 35 as a boundary (fulcrum), and as a result, folds, swells, etc. will occur, and the original shape accuracy required for the lens 33 cannot be obtained. Further, during processing, the contact area between the grindstone 35 and the lens 33 changes, so that the grinding / polishing pressure changes and the machining allowance changes.

In the conventional grinding / polishing grindstone, the coating coat 24 (see FIG. 10) is applied to the outer peripheral surface of the grindstone 35 to prevent electrolysis / oxidation.
It is not for increasing the outer diameter of.

Further, since the coating coat 24 is applied to prevent electrolysis / oxidation, unless a material different from the grindstone 35 itself, that is, a material such as silicon or polyimide having a high withstand voltage and a high insulation effect is used. I won't. Therefore,
When a material different from the wear degree and the longitudinal elastic coefficient of the main body of the grindstone 35 is used for the outer peripheral portion of the grindstone 35, when the lens 33 and the ring-shaped receiving member 34 are subjected to a compressive load, the lens 33
Further, the deformation of the ring-shaped receiving member 34 cannot be suppressed.

This is because when the outer peripheral portion of the grindstone 35 is a material having a high degree of wear or a material having a small longitudinal elastic coefficient, the outer peripheral portion of the grindstone 35 is worn or elastically deformed from the main body portion of the grindstone 35, and Only the main body portion comes into contact with the lens 33, and as a result, the lens 33 and the ring-shaped receiving member 34 are deformed. Conversely, when the outer peripheral portion of the grindstone 35 is made of a material having a low degree of wear or a large longitudinal elastic coefficient, the main body portion of the grindstone 35 is worn or elastically deformed from the outer periphery of the grindstone 35, and the outer peripheral portion of the grindstone 35 is However, the lens 33 and the ring-shaped receiving member 34 are deformed and the main body of the grindstone 35 is hard to contact the lens 33, so that sufficient grinding and polishing cannot be performed. That is,
Due to the relationship between the outer peripheral part of the grindstone 35 and the main part of the grindstone 35, even if the material is different, the degree of wear and the longitudinal elastic modulus are the same, and even if the lens 33 is brought into contact with the lens 33 during processing, adverse effects (such as scratches) will occur. If there is no material, there is no particular problem, but the above problems cannot be solved even if the conventional grinding / polishing grindstone is used.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide an optical element such as a lens, which is likely to be deformed, in a non-blocking grinding / polishing process with high accuracy. An object of the present invention is to provide a grinding / polishing grindstone capable of grinding / polishing.

Further, in addition to the object of the invention according to claim 1, an object of the invention according to claim 2 is to provide a grinding / polishing grindstone which does not cause a defect such as a scratch on an optical element during processing. Is.

The object of the invention according to claim 3 is that, in addition to the object of the invention according to claim 1 or 2, it is provided with a ring zone corresponding to the protrusion angle of an optical element suitable for obtaining a desired lens shape and the like. It is to provide a grinding and polishing whetstone.

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 is, in a grinding / polishing grindstone used when grinding / polishing an optical element, a grindstone portion composed of abrasive grains and a bond material. And a ring zone portion which is located on the outer periphery of the grindstone portion and is made of a material having the same degree of wear and longitudinal elastic coefficient as the grindstone portion.

In the invention according to claim 2, in the invention according to claim 1, the ring zone is made of the same material as the bond material used for the grindstone portion.

According to a third aspect of the invention, in the invention according to the first or second aspect, the outer diameter of the optical element to be processed is D, the radius of curvature is R, and the half angle sin ⁻¹ (D / 2R) of the optical element is θ.
_{When L} , the half angle θ _r of the ring zone is 0.25 θ _L or more.

1 to 4 are conceptual diagrams of the present invention. In addition, in FIG. 1 and subsequent figures, the same components as those of the related art will be denoted by the same reference numerals as those in FIGS. 11 and 12, and description thereof will be omitted. In FIG. 1, the lens 33 to be processed has an outer diameter D, a radius of curvature R, and a half angle θ _L of sin ⁻¹ (D / 2).
FIG. 6 is a vertical cross-sectional view of a non-blocking grinding / polishing process in which the lens 33 of R) is held by a holding tool 30.
FIG. 2 is a plan view thereof. In addition, FIG.
7 is a graph showing the experimental results on the relationship between the half-angle θ _L = sin ⁻¹ (D / 2R) and the protrusion angle θ _H of the lens 33.

As shown in FIGS. 1 and 2, this grinding / polishing grindstone includes a grindstone portion 2 made of abrasive grains and a bond material,
A ring zone located on the outer periphery other than the surface of the grindstone portion 2 that substantially contributes to grinding / polishing, has the same radius of curvature R as the grindstone portion 2, and is made of a material having the same degree of wear and longitudinal elastic coefficient as the grindstone portion 2. It is composed of a part 3 and the like.

In FIG. 3, the center of curvature of the lens 33 is O.
(It coincides with the swing center of the grindstone 1 during processing), the outermost peripheral position of the lens processing diameter is a, and the surface 33 to be processed of the lens 33 is
When the intersection of b and the center line (optical axis) of the lens 33 is c, the lens half angle θ _L = sin Further, FIG. 4 shows the lens radius θ _L = sin ⁻¹ (D / 2R).
And the protrusion angle θ _H of the lens 33 are shown by experiments. This is a whetstone 1
Oscillate while forcibly rotating by a motor,
When grinding / polishing is performed by rubbing the lens 33 against the grindstone 1, the outer peripheral portion of the grindstone 1 is relatively faster than the central portion of the grindstone 1, so that the surface 3 to be processed of the lens 33 is
In the state where the whole 3b is always in contact with the grindstone 1, that is, when the protrusion angle θ _H = 0, the relative speed of the outer peripheral portion of the lens 33 is inevitably increased, and as a result, the processing speed is increased. Then, the outer peripheral portion of the lens 33 is further ground and polished, and the desired lens shape cannot be obtained. In order to eliminate this, by changing the swing angle and protruding the lens 33, it is possible to prevent the outer peripheral portion of the lens 33 from being excessively ground / polished, and the outer peripheral portion and the central portion of the lens 33 are evenly ground / polished. As described above, the experiment was performed under the processing condition that the desired lens shape is obtained.

[0017]

First, the operation of the invention according to claims 1 and 2 will be described. When the lens 33 is set in the holder 30 and subjected to non-blocking grinding / polishing processing, the grindstone 1 must protrude from the lens 33 during processing in order to maintain the lens shape. According to the above configuration, when grinding / polishing is performed, even if the grindstone 1 swings to form a portion where the grindstone portion 2 does not come into contact with the lens 33, the ring portion 3 causes the lens 3 to move.
Since it is in contact with No. 3 (region 4), the contact area with the lens 33 of the grindstone 1 as a whole does not change. Moreover, since the ring portion 3 has no processing capability, it does not contribute to processing. As a result, the processing pressure does not change under the conventional processing conditions, and since the lens 33 is constantly pressed, the ring-shaped receiving member 3
The deformation (restoration) of No. 4 is suppressed, and the deformation of the lens 33 can be suppressed.

Further, in the present invention, an annular zone portion 3 made of a material having the same degree of wear and a longitudinal elastic modulus as that of the grindstone portion 2 is attached to the outer peripheral portion of the conventionally used grinding / polishing grindstone so as to be apparent. Since the size of the grindstone 1 is increased, it can be applied to any of a grinding wheel and a grinding wheel.

Next, the operation of the invention according to claim 3 will be described. In addition to the above-mentioned action, when the lens 33 is fitted to perform non-blocking grinding / polishing processing, the grindstone 1 must protrude from the lens 33 during processing in order to maintain the lens shape, but the protruding angle θ _H is as shown in FIG. From the slope of the approximate straight line obtained by approximating the experimental result of
It can be seen that it is 5θ _L. That is, by providing the ring zone portion 3 having a half-angle of 0.25θ _L or more, the effects of the above claims 1 and 2 become more effective.

[0020]

[Embodiment 1] FIGS. 5 and 6 are a longitudinal sectional view showing a processing state using a grindstone of this embodiment and an enlarged half-vertical sectional view of the grindstone.

(Structure) The lens 33, which is an optical element held by the holder 30, is polished by rotating and rocking the grindstone 1. As shown in FIG. 6, the grindstone 1 is made of a material having an outer diameter d, a grindstone portion (center portion) 2 made of abrasive grains and a bond material, and a material having the same degree of wear and longitudinal elastic coefficient as the grindstone portion 2 on the outer periphery thereof. And an annular portion 3 having an outer diameter d _T. Further, the grindstone portion 2 and the ring zone portion 3
Are independently formed, and are integrally formed by adhering to a base metal 10 made of metal such as stainless steel.

(Operation) According to the above configuration, when the grindstone 1 swings at an appropriate angle during processing, a portion of the surface to be processed of the lens 33 that does not contact the grindstone portion 2 having the outer diameter d is formed. That is, the grindstone portion 2 comes off the surface of the lens 33 to be processed. However, the outer diameter d _T , the half angle θ
_Since there is the ring zone 3 of _r , the lens 33 does not come off from the grindstone 1. As a result, the lens 33 is always pressed by the grindstone 1, the ring-shaped receiving member 34 is not deformed (restored), and the deformation of the lens 33 can be suppressed. Further, the processing pressure applied to the surface to be processed becomes constant.

(Effect) According to the present embodiment, since the ring zone portion 3 does not contain abrasive grains, it has no processing capability, and the same processing conditions as when processing with the grindstone of the grindstone portion 2 only. Since the lens 33 does not come into contact with the grindstone 1 due to the swing of the grindstone 1, there is no change in the machining allowance of the lens 33 to be processed, and folds and waviness do not occur. That is, the lens 33 is ground with high precision.
It can be polished. The half angle θ _r of the ring zone 3
Is preferably 0.25θ _L or more, and the material thereof is more preferably the same as the bond material of the grindstone portion 2.

[0024]

[Embodiment 2] FIG. 7 shows a half-vertical longitudinal sectional view of a grindstone of the present embodiment.

(Structure) The grindstone 1 of the present embodiment is composed of a grindstone portion 2 and an annular zone portion 3 as in the case of the first embodiment, but differs from the grindstone of the first embodiment in the following points. That is,
The disc-shaped base metal in this embodiment is a small disc-shaped base metal 15.
And a ring-shaped base metal 14 located on the outer periphery of the base metal 15.
It consists of and. Then, the grindstone portion 2 and the base metal 15,
In addition, the ring portion 3 and the base metal 14 are respectively bonded,
The grindstone portion 2 and the ring zone portion 3 are not bonded. Also, the whetstone portion 2 and the base metal 15 can be fixed by pressing the tips of the screws 11 screwed from the outer peripheral surfaces of the ring zone portion 3 and the base metal 14 against the side surfaces of the base metal 15.

(Operation) According to the above construction, the grindstone portion 2 and the base metal 15 and the ring portion 3 and the base metal 14 are provided with the screw 11
Since the ring zone 3 can be moved in the axial direction by loosening the screw 11, if the screw is fixed at the moving position, the relative height position between the grindstone portion 2 and the ring zone 3 can be obtained. Can be easily adjusted. Further, as in the first embodiment, since the ring portion 3 exists on the outer circumference of the grindstone portion 2, the lens 33 does not come off from the grindstone 1.

(Effects) According to this embodiment, the same effects as in Embodiment 1 are obtained, and at the same time, the surface 2a of the grindstone portion 2 containing abrasive grains and the surface 3a of the ring zone portion 3 not containing abrasive grains. As a result of abrasion, the heights of the grindstone portion 2 and the ring zone portion 3 change, and the relative height between the grindstone portion 2 and the ring portion 3 is changed by the screw 11 even if the radius of curvature R of the lens surface to be machined changes. Can be adjusted, so that it is possible to correct the radius of curvature R of the lens processed surface. The half-angle θ _r of the ring zone 3 is preferably 0.25 θ _L or more, and the same material as the bond material of the grindstone portion 2 is more preferable.

[0028]

[Embodiment 3] FIGS. 8 and 9 show a half-vertical longitudinal sectional view and a plan view of a grindstone of the present embodiment.

(Structure) In this embodiment, the grindstone used in the first embodiment is replaced with a pellet grindstone, and the central portion (grindstone part 2) of the grindstone 1 is a pellet grindstone 16 composed of abrasive grains and a bond material. The outer peripheral portion (ring portion 3) is composed of pellets 17 made of a material having the same degree of wear and longitudinal elastic modulus as the grindstone portion 2.

(Operation) According to the above-mentioned structure, like the first embodiment, when the grindstone 1 swings at an appropriate angle during processing, it is possible to prevent the lens 33 from always protruding from the surface of the grindstone 1. .

(Effects) According to this embodiment, the same effects as in Embodiment 1 can be expected, and at the same time, the widths of the grindstone portion 2 and the ring zone portion 3 can be adjusted depending on how the pellets are stuck. is there. That is, the length of the outer diameter d of the grindstone portion 2 or the half angle θ _r of the ring portion 3 can be changed depending on how the pellets are attached. Further, by using the pellets, in addition to the improvement of drainage, it also has a function of grinding / polishing the grindstone portion 2 and reducing frictional resistance of the ring zone portion 3. Further, as in the first and second embodiments, the half angle θ _r of the ring zone 3 is 0.25 θ _L
The above is desirable, and the material is more preferably the same as the bond material of the grindstone portion 2.

In the present invention, the grindstone portion and the ring zone portion having the same degree of wear and the same longitudinal elastic coefficient do not necessarily have to be made of the same material and may be made of different materials. Further, the same degree of wear and the same longitudinal elastic modulus include those having an approximate range even if they are not numerically completely the same and still exhibit the action and effect of the present invention.

[0033]

As described above, the grinding / polishing grindstone of the present invention has the following effects. The effect of the invention according to claim 1 is that in non-blocking grinding / polishing processing, high-precision grinding / polishing can be performed without deforming optical elements such as lenses.
That is, polishing can be performed. The invention according to claim 2 is
In addition to the effect of the first aspect, there is an effect of suppressing an adverse effect (such as generation of scratches) on the lens surface during processing. In addition to the above effects, the invention according to claim 3 further effectively provides an optical element such as a lens by providing a ring zone portion corresponding to a protrusion angle of the lens that corresponds to a processing condition when processing into a desired lens shape. High-precision grinding / polishing whetstone can be performed without deforming.

[Brief description of drawings]

FIG. 1 shows non-blocking grinding using the grindstone of the present invention.
It is a longitudinal cross-sectional view when performing a polishing process.

FIG. 2 is a plan view of the device shown in FIG.

FIG. 3 is a diagram showing a positional relationship between a half angle and a protrusion angle of the lens of the present invention.

FIG. 4 is a graph showing an experimental result regarding a positional relationship between a lens half angle and a protrusion angle.

FIG. 5 is a vertical cross-sectional view showing a processed state using the grindstone of Example 1 of the present invention.

FIG. 6 is a half-vertical longitudinal sectional view showing the grindstone of the first embodiment.

FIG. 7 is a vertical cross-sectional view of a whetstone according to a second embodiment of the present invention.

FIG. 8 is a semi-vertical longitudinal sectional view showing a grindstone of Example 3 of the present invention.

FIG. 9 is a plan view showing a grindstone of the third embodiment.

FIG. 10 is a vertical cross-sectional view showing a conventional grindstone.

FIG. 11 is a vertical sectional view showing a processing state using a conventional grindstone.

12 is a plan view of the device shown in FIG. 11. FIG.

[Explanation of symbols]

 1 grindstone 2 grindstone part 3 ring zone part 30 holder 33 lens

Claims (3)

[Claims] 1. In a grinding / polishing grindstone used for grinding / polishing an optical element, a grindstone part made of abrasive grains and a bond material is located on the outer periphery of this grindstone part, and has the same degree of wear and longitudinal elasticity as the grindstone part. A grinding and polishing whetstone characterized by being composed of an annular zone made of a material having a coefficient. 2. The grinding / polishing grindstone according to claim 1, wherein the ring zone is made of the same material as the bond material used for the grindstone. 3. When the outer diameter of the optical element to be processed is D, the radius of curvature is R, and the half angle sin ⁻¹ (D / 2R) of the optical element is θ _L , the half angle θ _r of the ring zone is 0.25 θ. _{It is L} or more, The grinding / polishing grindstone of Claim 1 or 2 characterized by the above-mentioned.