JPH0653580B2 - Glass lens molding equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a glass lens molding apparatus such as a camera lens used in optical equipment.

(Prior Art) Conventionally, as a glass lens forming apparatus, for example, Japanese Patent Publication No.
As proposed in Japanese Patent No. 38126, a method of pressing a glass lens material heated to a predetermined temperature with a pair of molding dies is used.

However, in the case of such an apparatus, the respective molding dies forming the lens surfaces are accurately aligned with each other and the respective lens surfaces are not tilted, that is, the lens optical axes are aligned with each other. It must be assembled and configured with high precision. Further, unless the volume of the glass lens material to be supplied is stabilized with high accuracy, the lens thickness or the lens surface shape accuracy cannot be obtained with high accuracy, and the predetermined optical performance such as the focal length cannot be obtained.

If the volume of the glass lens material to be supplied is made larger than the volume required for the molded lens, the lens thickness and lens surface shape can be obtained as desired, but excess lens material protrudes toward the outer periphery of the molding die, and after lens molding, the lens A centering process is required to keep the outer diameter constant. The centering work requires a large number of man-hours and increases the cost, and there is a possibility that the lens surface may be damaged in the working process, which is not preferable. Furthermore, the production efficiency is extremely poor due to the pair of molds.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional drawbacks, while allowing a large range of variations in the volume of lens material to be supplied, and eliminating the need for centering work after lens molding, and It is an object of the present invention to form a lens surface shape accuracy and a lens optical axis with high accuracy, and further to greatly improve the productivity of lens molding.

(Means for Solving the Problems) In order to achieve the above object, the glass lens molding apparatus of the present invention comprises a barrel-shaped plate having a plurality of through holes forming a molding cavity and arranged at a predetermined pitch. Using a molding die that fits into both end openings of each through hole to form a lens surface, and is configured to simultaneously mold a large number, a surplus glass escape portion is provided on at least one lens surface side of the molding die. It has a formed structure.

(Operation) According to the present invention, by the above-described means, the axial misalignment and inclination of the molding die are restricted by the barrel die to improve the lens surface accuracy, and the glass surplus is formed in the concave portion provided on the lens molding die surface side of the molding die. Inflowing and regulating the lens outer diameter with a barrel shape eliminates the need for centering work, greatly improving production efficiency,
The lens cost can be reduced.

(Example) Hereinafter, the Example of this invention is described based on drawing.

FIG. 1 is a front view of an essential part showing the concept of the device of the present invention, in which only the molding part is shown in cross section. FIG. 2 is a cross-sectional view of the barrel plate and a molding die fitted in a through hole of the barrel plate, that is, a molding cavity, and FIG. 3 is a bottom view of the barrel plate.

1 to 3, the body plate 2 is made of a predetermined ceramic material or the like, and the through holes 3 are arranged at a plurality of positions at a predetermined pitch. In the embodiment shown in FIG. 2, 4 in 2 rows and 2 columns is used.
It was a place. Through-hole 3 is a glass lens material 1 such as a sphere.
0 plays a role of a cavity for molding into a desired lens shape, and maintains the upper mold 5 and the lower mold 4 fitted from the openings at both ends in a predetermined positional relationship, that is, the axial centers of the molding dies 4 and 5 are deviated.
It has a function of keeping the inclination within a desired accuracy. In the embodiment shown in FIG. 2, the lower die 4 is fitted in advance to the lower end of the through hole 3 with a very small clearance, and the lower surface of the body die plate 2 and the end surface of the lower die 4 are flush with each other by the screw 9. It is fixed in place.

The upper mold 5 has a flange mold 11 and is inserted from the other open end of the through hole 3 in the direction of the arrow, and heats to a predetermined temperature to mold the glass lens material 10 in a softened state into a desired lens shape. The insertion depth of the upper die is determined by the flange portion 11 of the upper die 5 contacting the upper surface of the body die plate 2. That is, the desired thickness of the molded glass lens can be arbitrarily set by defining the thickness of the barrel plate 2.

The upper mold 5 and the lower mold 4 are formed of a predetermined ceramic material into a predetermined cylindrical shape, and one end surface of each mold is mirror-finished so that it has a predetermined lens surface shape orthogonal to the mold axis. There is. In the embodiment of the present invention, the mold surface shape is concave in order to obtain a convex lens.

The outer diameter of the cylindrical portion of the upper mold 5 and the lower mold 4 is configured to be larger than the effective system dimension of the molded glass lens 1 by a predetermined amount, and the outer edge portion of the upper mold 5 located outside the effective diameter on the molding die surface side. Is chamfered in a tapered shape to a predetermined size. The chamfered portion 5A becomes a space into which surplus glass of the glass lens flows.

The die set 14 shown in FIG. 1 is composed of an upper plate 12, a lower plate 6, a guide post 13 and a driving cylinder 8, and the upper plate 12 is slid by the driving cylinder 8 in the directions of arrows X and X ′ by a predetermined stroke amount. Further, a cartridge heater 7 and a temperature sensor (not shown) are embedded in the upper plate 12 and the lower plate 6 to heat each plate to a predetermined temperature that softens the glass lens material.

Next, the die set 14, the body plate 2, and the upper mold 5 described above.
A process of molding a desired molded glass lens using the lower mold 4 will be described.

First, the spherical glass lens material 10 is supplied into each through hole 3 of the body mold plate 2, and then the upper mold 5 is fitted in a predetermined manner. Thereafter, the barrel plate 2 is heated using a predetermined heating device such as a tunnel furnace, an oven, or a means (not shown) such as on a hot plate to heat the glass lens material to a softened state in which it can be molded.

Then, the barrel plate 2 heated to a predetermined temperature is placed on the lower plate 6 of the die set 14, and the upper plate 12 located at the position indicated by the chain double-dashed line is lowered to the predetermined position indicated by the solid line to form the upper mold 5 The glass lens material 10 is press-molded in a predetermined manner via. After that, when the flange portion 11 of the upper die comes into contact with the upper surface of the barrel plate 2, the barrel plate 2 is removed from the die set, and the molded lens is cooled to a predetermined temperature, whereby the molded glass lens 1 is completed.

In the above embodiment, the glass lens material 10 to be supplied
It goes without saying that the volume of the glass lens material is slightly smaller than the volume of the molding cavity formed by the through hole 3 and the molding dies 4 and 5, and the glass lens material volume variation range is on the molding lens surface side of the upper mold 5. It is the same as setting the volume of the chamfered portion 5A provided therein. Therefore, by providing the chamfered portion 5A, it is possible to satisfy not only the allowable range of the lens material volume but also the obtained optical axis accuracy of the lens, the lens thickness, and the transfer accuracy of both surfaces of the lens at the same time. become.

FIGS. 4 and 5 show another embodiment of the barrel plate, and exemplify a barrel plate 20 of a three-part type. In this case, each through hole 4A is configured so as to be splittable around the axisymmetric center, and the three plates 20A, 20B, 20
Each through hole 3A is processed in a state where B is integrated with the fastening screw 15. The purpose of constructing the barrel plate 20 in a divided form is as follows: 1) The molded lens is easily taken out from the through hole.

2) Make it easy to apply the glass release agent to the inner wall surface of the through hole.

3) If the seizure phenomenon occurs between the upper die and the through hole due to some reason during the sliding operation, it will be easier to repair.

This is because.

(Effect of the Invention) As described above, the volume variation of the glass lens material can be absorbed by allowing it to escape to the surplus glass escape portion of the molding die as surplus glass, thus eliminating the need for centering work. Further, by using the barrel-shaped plate, it is possible to highly accurately regulate the axial misalignment and inclination of the lens surfaces and the lens thickness dimension. Further, by molding a large number of them at the same time, there are great effects such as improvement in productivity, reduction in lens cost, and simplification of molding equipment.

[Brief description of drawings]

FIG. 1 is a front view of an essential part showing the concept of the device of the present invention, FIG. 2 is a cross-sectional view of a barrel plate that constitutes the device of the present invention, and a molding die fitted to the barrel plate, and FIG. FIG. 4 is a bottom view of FIG. 4, and FIG. 4 is a plan view of another body plate of another embodiment of the present invention.
FIG. 5 is a cross-sectional view of FIG. 4 taken along the line S--S. 1 ... Molded glass lens, 2, 20 ... Body plate,
3, 3A ... through hole, 4 ... lower mold, 5 ... upper mold, 5A ...
... Chamfer, 6 ... Lower plate, 7 ... Cartridge heater, 8 ... Drive cylinder, 10 ... Glass lens material, 11 ... Flange, 12 ... Upper plate, 14
...... Die set.

Claims (4)

[Claims] 1. A barrel plate having a plurality of through holes arranged at a predetermined pitch, a mold for fitting a lens surface into each opening of both ends of the through hole, the barrel plate and the plate. The mold includes means for heating the mold to a predetermined temperature, and means for pressing the plurality of molds in the axial direction of the through hole all at once, and the excess is provided on at least one lens surface side of the mold. A glass lens molding device, characterized in that a glass relief portion is formed. 2. A molding die on the side on which at least one lens surface is formed is independently arranged so as to be movable in the axial direction of the through hole.
The glass lens molding device according to the item. 3. The structure according to claim 2, wherein a desired lens thickness is obtained in a state where a flange portion of the forming die is in contact with a main plane of the barrel plate. The glass lens molding device described. 4. The glass lens molding apparatus according to claim 3, wherein the through-hole is separable about the axisymmetric center in the body plate.