JPH09156945A - Cutting of glass with side pressure and optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cutting glass with a side pressure, capable of simultaneously cutting a brittle material such as a glass bar on plural cross sections and surely obtaining plural glass materials whose cut surfaces are smooth and similar to mirror surfaces and whose weights are little in irregularity, on the production of optical elements such as lenses used in various optical equipments. SOLUTION: A cutting means comprises a glass bar 1 comprising a brittle material, a press member used for forming cutting marks on the outer surface of the glass bar 1 and uneven in the ridge, a means equipped with the press member and used for repeatedly forming the marks 2 on the glass bar with a constant load for each constant distance, a side pressure-transmitting cylinder 3 which comprises a material small in the Young modulus and into which the glass bar 1 having the marks 2 is fit, a hydraulic medium 4 filled between the glass bar 1 and the transmitting cylinder 3, and a means for preventing the deformation of the transmitting cylinder in the axial direction. The cutting means applies a side pressure P to the glass bar along the outer periphery of the transmitting cylinder 3 to cut the glass bar along the plural marks 2 formed on the glass bar 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass cutting method, and particularly to a glass material used for molding an optical element such as a lens by pressing, for example, a rod-shaped long glass, to obtain a high quality cut surface. The present invention relates to a glass cutting method and an optical element in a field in which the glass cutting process is required and a glass cutting process suitable for mass production is required.

[0002]

2. Description of the Related Art Conventionally, a mass production technology for aspherical glass lenses has been established by a molding method suitable for mass production of aspherical glass lenses, and has been achieved to date. Most of optical element materials used for molding glass lenses have a polished, ball, or polished cylindrical shape.

Recently, based on the view that an optical glass element material is a brittle material, a glass rod or the like is cut by lateral pressure without using a tool such as a conventional diamond cutter. JP-A-61-266323 A so-called lateral pressure cutting method as disclosed in the publication is known. The side pressure cutting method does not involve generation of chips or noise at the time of cutting, and does not require unnecessary time and energy at all. Further, the disking method disclosed in Japanese Patent Laid-Open No. 6-198600, in which glass rods and the like are cut at a plurality of cross sections at the same time, can obtain a large amount of optical element materials by cutting a plurality of cuts by increasing the lateral pressure once. To be

However, in the disking method, the clearance between the transmission tube and the glass rod, the thickness and material of the transmission tube, the mechanical elements such as the tightening margin of the ring-shaped rubber for sealing the high pressure, the peak pressure value and the pressurizing time. Since the setting condition elements such as hold time are complicatedly entangled, the optical element obtained by cutting a plurality of cross-sections from the designated scratches has the same cross-sectional shape, that is, the same optical appearance and the same weight. Things are very difficult. Further, in order to specify the cut portion, a streak as shown in FIG. 8 is provided in advance on the outer surface of the glass rod at regular intervals. However, the surface quality of the uncut or cut surface depends on the shape of the streak. However, there is a problem in that it cannot be used as a material for an optical element because of deterioration of the material or variation in weight of each material.

[0005]

SUMMARY OF THE INVENTION In the present invention, in consideration of the loss in the conventional cutting technique, a simple means is used for the outer surface of a rod-shaped workpiece made of a brittle material such as glass in the above-mentioned disking method. After improving the surface shape of the indenter that provides the streak to be cut so that the streak of a specific shape is generated, it is possible to reliably cut the rod-shaped workpiece simultaneously at each cross section specified by the lateral pressure. An object of the present invention is to obtain a plurality of columnar glass materials that enable a smooth cut surface, particularly a cut surface close to a mirror surface, and have less variation in weight.

[0006]

In order to achieve the above object, in the present invention, a plurality of cross sections to be cut with an indenter are designated in advance on the outer surface of a rod-shaped workpiece made of a brittle material such as glass. Although the streaks are provided, the surface of the indenter is adjusted to a predetermined shape, and the streaks are appropriately roughened by the unevenness of the ridgeline of the indenter to obtain an optical element material.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is a rod-shaped workpiece made of a brittle material with little plastic deformation, and an uneven ridge line provided on the outer surface of the workpiece with a striation to be cut. An indenter, a means that includes the indenter and repeatedly provides the ridge with a constant load at a constant distance, and a side pressure transmission cylinder made of a material having a small Young's modulus into which the workpiece with the ridge is fitted. A pressure medium filled between the workpiece and the transmission cylinder, and means for restraining axial deformation of the transmission cylinder, which is composed of a ring-shaped rubber, a supporting member, and a holding member, and the outer circumference of the transmission cylinder. Is a method of cutting glass by lateral pressure, characterized in that a lateral pressure is applied along and the material is cut along the striations provided on the workpiece via the pressure medium. Localized surface generated at the contact surface between the object and the transfer tube The work piece, which is loaded with lateral pressure by the friction force and the wedge effect generated in the striation of the work piece by the pressure medium, induces a stress perpendicular to the axial direction, and as a result, the transfer to the work piece is performed. A tensile force is not generated outside the both ends of the cylinder, and the cutting is instantaneously caused by the lateral pressure. Therefore, the work can be simultaneously cut at a plurality of scratch positions.

According to a second aspect of the present invention, similar to the indenter, a rotary roller having ridges and ridges is provided, and the rotary roller repeatedly applies a constant load to the workpiece at constant distances. A mark is provided, The mark is characterized by the above-mentioned.
It is a method of cutting glass by the lateral pressure described,
Similar to the above, it has the effect of enabling simultaneous cutting at a plurality of striation positions on the workpiece.

An embodiment of the glass cutting method of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a cross-sectional view of a cutting device used for cutting a glass rod, and FIG. 2 is a perspective view showing a method of making a striation 2 on the outer peripheral surface of the glass rod 1.

An embodiment of a specific apparatus for applying a uniform lateral pressure P to the side surface of the glass rod 1 will be described with reference to FIG. In the figure, reference numeral 2 designates a plurality of streaks previously provided on the outer surface of the glass rod 1 for designating the cut surface.
The glass bar 1 is fitted into the transmission tube 3 via the pressure medium 4, and the clearance between the glass bar 1 and the transmission tube 3 is several tens μm. Ring-shaped rubbers 5 called O-rings are fitted on both ends of the transmission cylinder 3, and the two ring-shaped rubbers 5 are attached to the first support member 6 and the second support member 7 for positioning. They are fitted into each other and are brought into close contact with the transmission cylinder 3 by moving the holding member 8 toward the ring-shaped rubber 5 side by a certain distance. In such a state, it was sandwiched between the respective ring-shaped rubbers 5 by the two ring-shaped rubbers 5 fitted onto the glass rod 1 via the first supporting member 6 and the second supporting member 7. The outer peripheral portion of the transfer cylinder 3 and the inner peripheral portion of the pressure vessel 11 can be sealed between the pressure chambers 9 to form the pressure chamber 9. Therefore, while operating oil is flown from the hydraulic device (not shown) into the pressure chamber 9 of the pressure vessel 11 through the pressure raising hole 10, the glass rod 1
A uniform lateral pressure P can be applied to the side surface of the.

Regarding the method of cutting the glass rod 1, prior to the cutting, an indenter 12 previously placed on the cutting position on the outer surface of the glass rod 1 is used to adjust the cutting position of the glass rod 1. The streak 2 must be provided on the outer surface to easily induce cutting. The indenter 12 is
By making contact with the glass rod 1 from the vertical direction at a load W and a constant velocity V ₁ , the striation 2 is formed. The streak 2
Is adjusted at an angle that is parallel to the circumferential direction of the glass rod 1. The indenter 12 for making the striations 2 on the glass rod 1 has a ridge 14 as shown in FIG.

FIG. 3 is a plan view showing the scratches 2 formed on the outer surface of the glass rod 1, FIG. 4 is an enlarged view of the scratches 2, and FIG. 5 is an enlarged view of the tip of the indenter 12. is there.

As shown in FIG. 5, the tip shape of the indenter 12 is finish-polished on the uneven surface 13 using artificial diamond abrasive grains so that a certain unevenness is formed at a pair of arbitrary angles. The ridgeline 1 where the uneven plane 13 intersects
In No. 4, irregular unevenness occurs.

When the streak 2 formed on the outer surface of the glass rod 1 is enlarged by using the indenter 12 having irregular irregularities on the ridge line 14, the streak 2 is surrounded by the ridge line 2 as shown in FIG. As shown in (1), countless microcracks were generated by the indenter.

The principle up to the cutting of glass will be briefly described with reference to FIG. First, the glass rod 1
By filling the clearance of the transmission cylinder 3 with the pressure medium 4 and applying the lateral pressure P, a compressive stress is generated on the outer surface of the glass rod 1 and a tensile stress is generated on the central portion thereof, and at the same time, the outer surface of the glass rod is formed. The pressure medium 4 enters the streaks 2 of the pressure medium 4, the pressure medium 4 acts as a wedge effect, and due to the frictional force generated between the transmission tube 3 that tries to extend in the axial direction and the glass rod 1 that has a poor extension amount. It becomes possible to cut by lateral pressure.

The specific conditions according to the first embodiment will be described below. The work piece has a Young's modulus of 103 × 10 ² k
The glass rod 1 is a solid cylinder having an outer diameter of 7 mm of gf / mm ² and used for lens molding. The glass rod 1
The streak 2 for designating the cutting surface is stamped by the indenter 12. The indenter 12 used is made of diamond, has a blade width of 1.6 mm, and has ridges 14 with irregularities of 2 to 10 μm. The glass rod 1 uses the indenter 12, applies a load of 1000 g or less, and presses it on the outer surface of the glass rod 1 at a speed of 0.4 mm / s to insert the striations 2 to perform these operations. Repeatedly, the streak 2 is 3 m
Twelve locations were provided in the axial direction of the glass rod 1 at intervals of m. The length of the streak 2 was 270 μm, and all had the same shape as viewed with a stereoscopic microscope.

In the apparatus according to FIG. 1, the glass rod 1 having the scratches 2 was fitted in an acrylic resin transmission cylinder 3, and castor oil was sealed as a pressure medium 4 in the clearance. Further, the length of the transfer cylinder 3 is 40 mm, and each ring-shaped rubber 5 has a wire diameter of 1.2 mm and is fitted into and brought into close contact with the stepped portions of the first support member 6 and the second support member 7, respectively. There is. The holding member 8 moves 1 mm toward the ring-shaped rubber 5 and deforms the side surfaces of the two ring-shaped rubbers 5 to enhance the airtightness of the pressure chamber 9. As a result of such a state, the side pressure P due to the hydraulic pressure is 90
At 0 kgf / cm ² , the fitted glass rod 1 was cut at a cross section passing through all the scratches 2, and the cut surfaces at this time were all mirror surfaces.

The columnar glass material obtained by cutting is 13
As a result, the individual weight variation was ± 3.2% with respect to the average weight per piece.

FIG. 9 shows an optical element 17 formed by heating, pressurizing and cooling an optical element material obtained by cutting by lateral pressure. This optical element 17 is used as one of lenses for video movies, and has a double-sided convex shape with one surface being aspherical and the other surface being spherical. The transfer surfaces of the first molding die 18 and the second molding die 19 used for molding are processed into desired concave shapes, and are fitted in the upper and lower inner diameter portions of the body mold 20, respectively. The transfer accuracy of the optical element obtained through the molding process was the same as when the optical element material having another shape was molded, and the performance was satisfactory in terms of optical characteristics.

From the results of this specific embodiment, the action and effect of the cutting method of the present invention were verified.

In the first embodiment, the pressure medium 4 filled in the clearance between the glass rod 1 and the transmission cylinder 3 is used.
Although castor oil was selected as the medium, regardless of the material of the glass rod 1 to be cut, if the medium has properties similar to those of the castor oil, such as viscosity and wettability, similar effects can be obtained and lateral pressure can be obtained. It is also possible to implement it by adding a time change to the boosting method of.

(Embodiment 2) FIG. 7 shows Embodiment 2 and is a perspective view of an apparatus equipped with a rotary roller 15 for making a striation 2 on the outer surface of a glass rod 1.

The rotary roller 15 is fixed to the roller holding member 16 via a shaft fitted in the central portion of the roller, and is a mechanism for freely rotating. The rotary roller 15 reciprocates at a constant speed V ₂ in a horizontal direction perpendicular to the axial direction of the glass rod 1, and the glass rod 1 is
Since the glass rod 1 moves at the designated intervals, the scratches 2 are locally provided on the outer surface of the glass rod 1 at every distance designated by an angle parallel to the circumferential direction of the glass rod 1.

The above-described second embodiment will be specifically described below. The work piece used in the experiment has a Young's modulus of 53.7 × 1
The glass rod material 1 for lens has a solid cylinder shape of 0 ² kgf / mm ² and an outer diameter of 4.3 mm and has the same shape as that of the first embodiment. The rotary roller 15 is a carbide roll cutter, and the ridge line 14 is provided with irregular asperities of 2 to 10 μm as in the first embodiment. The contact pressure of the rotary roller 15 is 0.
It was set to ² kg / cm ² and reciprocated at a moving speed of 40 mm / s, and the glass rod 1 was provided with the above-mentioned striations 2 at 7 positions at intervals of 4.9 mm. The length of the streak 2 is 800 μm
Met.

In the same apparatus as shown in FIG. 2, the glass rod 1 with the scratches 2 is 650 kgf / cm ^2.
All lateral cross sections were cut by the lateral pressure P of, and all the cut surfaces became mirror surfaces. In this way, the method of cutting the glass rod 1 is
Also in the above configuration, the same operation and effect as those of the first embodiment can be obtained.

The number of columnar glass materials obtained by cutting was 8, and the variation in weight of each was ± 1.5% with respect to the average weight per piece.

In the case of the second embodiment, needless to say, even if the glass rod 1 is composed of a plurality of glass rods (two or more), the scratches 2 can be obtained similarly to one glass rod. .

[0029]

As described above, according to the present invention, there is no generation of chips or noise at the time of cutting, no unnecessary time and energy are required for cutting, and a plurality of lateral pressure increases at one time. The cutting of the part is performed, and a large amount of optical element material is obtained. Further, the cut surface is close to a mirror surface, and it is possible to manufacture an optical element material with little weight variation, and a desired lens shape is manufactured through a press molding process, so an inexpensive and high quality optical element can be provided. .

[Brief description of the drawings]

FIG. 1 is an explanatory view of an apparatus for carrying out the cutting method of the present invention.

FIG. 2 is a perspective view showing a method for making a striation on a glass rod according to the first embodiment of the present invention.

FIG. 3 is an explanatory view showing streak marks on the outer surface of the glass rod material of the present invention.

[Figure 4] Enlarged view

FIG. 5 is an enlarged view showing the tip shape of the indenter of the present invention.

FIG. 6 is an explanatory view showing a schematic principle of the cutting method of the present invention.

FIG. 7 is a perspective view showing a method for making a striation on a glass rod according to the second embodiment of the present invention.

FIG. 8 is an enlarged view showing streaks on the outer surface of a conventional glass rod.

FIG. 9 is an explanatory diagram showing an optical element obtained by molding.

[Explanation of symbols]

 1 glass rod 2 streak 3 transmission cylinder 4 pressure medium 5 ring-shaped rubber 6 first support member 7 second support member 8 holding member 9 pressure chamber 10 pressure raising hole 11 pressure vessel 12 indenter 13 uneven surface 14 ridge line 15 Rotary roller 16 Roller holding member 17 Optical element 18 First molding die 19 Second molding die 20 Body

Claims (3)

[Claims] 1. A rod-shaped workpiece made of a brittle material with little plastic deformation, an indenter having ridges and ridges on the outer surface of the workpiece for providing a scratch to be cut, and the indenter repeatedly provided at regular intervals. Means for providing the ridge with a constant load, a side pressure transmission cylinder made of a material having a small Young's modulus into which the workpiece with the ridge is inserted, and a pressure filled between the workpiece and the transmission cylinder. Medium, ring-shaped rubber, support member,
And a means for restraining the axial deformation of the transmission cylinder formed of a holding member, a lateral pressure is applied along the outer circumference of the transmission cylinder, and a plurality of workpieces are provided on the workpiece via the pressure medium. A method for cutting glass by lateral pressure, which is characterized in that the glass is cut along the streak. 2. Similar to the indenter, a rotary roller having ridges and valleys is provided, and the rotary roller is provided with a scratch on the workpiece with a constant load at every constant distance. The method for cutting glass by lateral pressure according to claim 1, wherein 3. The method according to claim 1, wherein a plurality of independent molding blocks composed of a pair of molding dies and a barrel mold are provided between the molding dies.
An optical element obtained by placing the optical element material obtained by the cutting method described above, heating, pressurizing, and cooling, and then taking it out from the molding block.