JP2002126986A - Lens machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress damage to a lens surface or a tool surface, and to stabilize curvature accuracy of a lens by chamfering a lens surface peripheral portion of a concave spherical/aspherical lenses and the like to prevent chipping in a lens surface peripheral portion, at the time of grinding/polishing. SOLUTION: In a machining method for a concave spherical/aspherical lenses, a lens surface peripheral portion generated and ground to have a generally concave spherical shape by generating and grinding machining is subjected to chamfering. In this chamfering machining, the lens surface peripheral portion is pressed against a convex formed dish-shaped tool having a larger radius of curvature than that of the lens surface, and the formed dish-shaped tool is rotated while supplying grinding fluid to chamfer the lens surface peripheral portion. After that, to a lens having a chamfered lens surface peripheral portion, fine grinding and polishing are conducted by using a dish-shaped tool having a convex shape generally reversing the lens shape, thereby finishing the lens surfaces of the concave spherical/aspherical lenses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing an optical element such as a lens, and more particularly to processing a lens surface of a lens having a concave curved surface such as a concave spherical lens or a concave aspheric lens. The present invention relates to a lens processing method.

[0002]

2. Description of the Related Art Processing of an optical element such as a convex lens or a concave lens is usually performed according to a process flow as shown in FIG. 4, and will be described below with reference to FIG.

[0003] A blank (S101) in which a glass material is formed into a predetermined shape by press molding or the like is put into a lens processing step. First, in a generating grinding step (S102), the lens surface is substantially processed by a processing machine such as a curve generator. The original grinding process is performed in a spherical shape, and then the fine grinding process (S1
03) and in the polishing step (S104), the surface of the lens is adjusted while supplying a grinding fluid by using a dish-shaped tool having a shape obtained by sintering diamond abrasive grains and a metal material or resin as main components and inverting the lens shape. Fine grinding, then polishing the lens surface by applying a polishing liquid using a dish-shaped tool with a shape that is approximately inverted, pasting a polishing sheet such as a polyurethane sheet and finishing the lens surface . The fine grinding may be performed in two stages. Then, in the centering step (S105),
Centering is performed by holding the lens between a pair of cup-shaped holders and centering it, while rotating the lens around its center line, grinding the side peripheral surface of the lens into a perfect circle with a diamond grindstone, etc. .

[0004] In processing a lens surface of a lens having a concave curved surface such as a concave spherical lens or an aspherical lens, the lens surface is formed into a substantially concave spherical shape in the generating grinding step (S102). After processing, the substantially concave spherical lens surface is finely ground (S103) and polished (S10).
4). At this time, as shown in FIG. 5, the glass lens after the creation grinding process has a sharp edge at the peripheral portion 12a of the lens surface 12 of the substantially concave spherical shape of the glass lens 11, and is in a blade state. A glass lens 11 having a lens surface peripheral edge 12a at an acute angle and in a blade state is supplied to a grinding / polishing machine for fine grinding or polishing.

[0005]

However, when processing a lens surface such as a concave spherical lens or an aspherical lens as described above, the peripheral edge portion of the concave lens surface after the generation grinding is formed at an acute angle. If the glass lens in the state is finely ground or polished as it is, when the glass lens is attached to or detached from the grinding / polishing machine, the peripheral edge of the lens surface comes into contact with the processing tool, and the sharp edge of the peripheral surface of the lens becomes sharp. It often occurs that a part is lost. When grinding or polishing is performed as it is in a state where the lens peripheral portion is missing,
Processing is performed in a state where broken pieces remain between the tool and the lens surface, and there is a problem that the lens surface and the tool surface are damaged. Furthermore, the edge of the lens surface, which is in the state of the blade of the glass lens, cuts the tool surface, and the curvature accuracy of the tool cannot be maintained.
There is a problem that the curvature accuracy of the processed lens becomes unstable.

Accordingly, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and has been made in consideration of the above-described problems, and has been made in consideration of the lens surface of a lens having a concave curved surface such as a concave spherical lens or an aspherical lens. By chamfering the peripheral edge of the lens, it eliminates the loss of the peripheral edge of the lens surface during grinding and polishing processing, suppresses the occurrence of damage to the lens surface and tool surface, and stabilizes the curvature accuracy and optical accuracy of the lens It is an object of the present invention to provide a method of processing a lens that can be performed.

[0007]

In order to achieve the above object, a lens processing method according to the present invention is directed to a lens processing method for finishing a lens surface of a lens having a concave curved surface by generating grinding, fine grinding and polishing. A chamfering process is applied to the peripheral edge of the lens surface that has been generated and ground to a substantially concave spherical shape by the generating grinding process, and then fine grinding and polishing are performed using a convex dish-shaped tool having a substantially inverted lens surface shape. To finish the lens shape.

In the lens processing method of the present invention, the peripheral edge of the lens surface is chamfered by bringing a convex dish-shaped tool having a radius of curvature larger than the radius of curvature of the lens surface into contact with the peripheral edge of the lens surface. It is preferable to perform the rotation.

In the lens processing method of the present invention, the generation grinding can be performed by a curve generator so that the lens surface is formed into a substantially concave spherical shape.

In the lens processing method of the present invention, fine grinding and polishing can be performed using a convex dish-shaped tool formed by sintering diamond abrasive grains and a metal material or resin as main components. .

In the lens processing method of the present invention, the lens having a concave curved surface is a concave spherical lens or a concave aspheric lens.

[0012]

According to the present invention, when processing a lens having a concave curved surface such as a concave spherical lens or a concave aspherical lens, the peripheral edge of the concave lens surface is chamfered after the generation grinding. By performing the above process, it is possible to perform fine grinding and polishing as a post-process in a state where the peripheral portion of the lens surface is obtuse and the sharpness like a blade is eliminated. Part of the portion is less likely to be lost, the occurrence of damage to the lens surface can be suppressed, and the appearance of the lens surface can be improved.
The curvature accuracy of the tool can be maintained without cutting or damaging the tool surface, and a lens having excellent curvature accuracy and optical accuracy can be stably manufactured.

[0013]

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

FIG. 1 is a process diagram showing a process flow of a lens processing method according to the present invention, and FIG. 2 shows an aspect in which a chamfer is performed on a peripheral portion of a lens surface in a chamfering step in the lens processing method according to the present invention. FIG. 3 is a schematic view for explaining, and FIG. 3 is a partial cross-sectional view of a glass lens having a chamfered edge portion on the lens surface according to the present invention.

The lens processing method of the present invention will be described with reference to the process flow shown in FIG. The blank (S1) in which a glass material is formed into a predetermined shape by press molding or the like,
It is put into the lens processing process, and first, the creative grinding process (S
In 2), the blank lens surface is formed and ground into a substantially concave spherical shape by a processing machine such as a curve generator.

Next, in the chamfering step (S3), the glass lens that has been formed and ground into a substantially concave spherical shape is
As shown in FIG. 2, chamfering is performed on the peripheral edge of the lens surface. In FIG. 2, reference numeral 1 denotes a glass lens whose lens surface 2 is formed and ground into a substantially concave spherical shape, and the lens surface peripheral edge portion 2a is at an acute angle in a blade state. Reference numeral 4 denotes a convex shaped dish-shaped tool having a radius of curvature larger than the radius of curvature of the lens surface 2 of the glass lens 1, and is mounted on a jig 5 and fixed to a lower shaft of a rotation mechanism device (not shown). By directly holding the glass lens 1 with a hand or through a lens holding jig 6, the peripheral edge 2 a of the lens surface 2 is formed into a convex shaped dish-shaped tool 4.
Press against the surface. Then, while rotating the mold dish tool 4 in the direction shown by the arrow a by a rotation mechanism device (not shown), and supplying the grinding fluid 7, the glass lens 1 is placed on the surface of the mold dish tool 4 having a convex shape. Rock it. As a result, the peripheral edge 2a of the glass lens 1, which is in the blade state at an acute angle, comes into contact with the convex shaped dish-shaped tool 4 and is chamfered, as shown in FIG. Is chamfered 3.

Thereafter, the glass lens 1 having the chamfered edge portion 2a of the lens is produced according to the process flow of FIG.
In the fine grinding step (S4) and the polishing step (S5), fine grinding and polishing are sequentially performed. At the time of precision grinding and polishing, a diamond-like grain and a metal dish or a resin are used as the main components, and a convex dish-shaped tool whose lens shape is substantially inverted by sintering is used while supplying a grinding fluid to the lens surface. Fine grinding is performed, and polishing is performed while supplying a polishing liquid to finish the lens surface. Then,
In the centering step (S6), centering is performed by holding the glass lens between a pair of cup-shaped holders, and while rotating the glass lens around its center line, the side peripheral surface of the glass lens is rounded with a diamond grindstone. Perform centering to grind.

As described above, when a curved surface of a lens having a concave curved surface, such as a concave spherical lens or an aspherical lens, is formed, a convex mold having a radius of curvature larger than the radius of curvature of the lens surface after the generation grinding process. Using a dish-shaped tool or the like, chamfering the peripheral edge of the lens surface to make the peripheral edge of the lens obtuse to eliminate sharpness like a blade, and then, for the lens surface whose peripheral edge is chamfered, By performing precision grinding and polishing, the lens surface periphery is not damaged even when the lens surface periphery and the tool come into contact when the glass lens is grounded and removed from the polishing machine. , Furthermore, without damaging or damaging the tool, it suppresses the occurrence of damage to the lens surface and tool surface,
In addition, the processing of the lens can be continued with stable curvature accuracy.

Further, in the above-described embodiment, the lens periphery is pressed against a convex dish-shaped tool having a radius of curvature larger than the radius of curvature of the lens surface to perform chamfering. Chamfering of the periphery of the surface can also be performed. For example, chamfering can be performed by pressing a convex shaped dish-shaped tool having a radius of curvature larger than the radius of curvature of the lens surface against the peripheral portion of the lens surface and rotating the tool. Further, the shape of the chamfer may be either a flat surface or a curved surface.

[0020]

As described above, according to the present invention,
When processing a lens having a concave curved surface such as a concave spherical lens or a concave aspheric lens, by performing chamfering on the peripheral edge of the concave lens surface after the generation grinding process, the lens surface peripheral edge is reduced. In the state where the sharpness like a blade is eliminated by performing an obtuse angle, fine grinding and polishing as a post-process can be performed, and in the fine grinding and polishing, a part of the lens surface peripheral portion is less likely to be lost. Therefore, the occurrence of damage to the lens surface can be suppressed, the appearance of the lens surface can be improved, and the curvature accuracy of the tool can be maintained without cutting or damaging the tool surface, A lens excellent in curvature accuracy and optical accuracy can be stably manufactured.

[Brief description of the drawings]

FIG. 1 is a process chart showing a process flow of a lens processing method according to the present invention.

FIG. 2 is a schematic diagram for explaining an aspect of chamfering a lens surface peripheral portion in a chamfering step in the lens processing method according to the present invention.

FIG. 3 is a partial cross-sectional view of a glass lens having a chamfered edge on the lens surface according to the present invention.

FIG. 4 is a process chart showing a process flow of a conventional lens processing method.

FIG. 5 is a partial cross-sectional view of a glass lens having a concave lens surface manufactured by a conventional lens processing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 (Glass) lens 2 (Concave) lens surface 2a Peripheral edge 3 Chamfering 4 (Convex) dish-shaped tool 5 Jig 6 Lens holding jig 7 Grinding fluid

Claims (5)

[Claims] 1. A lens processing method for finishing a lens surface of a lens having a concave curved surface by generating grinding, fine grinding, and polishing, wherein a peripheral surface of the lens surface that has been generated and ground into a substantially concave spherical shape by generating grinding. A lens processing method comprising: performing a chamfering process; and thereafter, performing fine grinding and polishing using a convex dish-shaped tool having a substantially inverted lens surface shape to finish the lens shape. 2. The chamfering of the peripheral edge of the lens surface is performed by rotating a convex dish-shaped tool having a radius of curvature larger than the radius of curvature of the lens surface in contact with the peripheral edge of the lens surface. The lens processing method according to claim 1, wherein: 3. The lens processing method according to claim 1, wherein the generating grinding is performed by generating the surface of the lens into a substantially concave spherical shape using a curve generator. 4. The fine grinding process and the polishing process are performed using a convex dish-shaped tool formed by sintering diamond abrasive grains and a metal material or resin as main components. 4. The lens processing method according to any one of 3. 5. The lens processing method according to claim 1, wherein the lens having the concave curved surface is a concave spherical lens or a concave aspheric lens.