JPH05294645A - Device for molding glass lens - Google Patents

Abstract

PURPOSE:To provide a device for molding glass lenses applicable to convex lenses thickly expanding at the center, capable of securing high-precision thickness. CONSTITUTION:A device for molding glass lenses is equipped with an upper mold 1 provided with an inside mirror barrel 2 for the upper mold, a lower mold 4 provided with an inside mirror barrel 5 for the lower mold and opposing the upper mold 1 and a glass cob 7 arranged between the upper mold 1 and the lower mold 4. The pressing part of the inside mirror barrel 5 for the lower mold is provided with a mirror frame 6 which stores surplus glass of the glass cob 7 during mold of glass lens, is bent with pressure contact with the inside mirror barrel 2 for the upper mold and clamped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a glass lens molding apparatus for molding a glass lens used in optical equipment by a precision glass molding method.

[0002]

2. Description of the Related Art In recent years, high-precision glass lenses are manufactured by so-called one-shot molding in which a polishing step is omitted from the viewpoint of suppressing manufacturing cost, and it is generally desired that the thickness thereof be within ± 0.03 mm. ing. In order to satisfy this requirement, at least the volumetric accuracy of the glass cob, which is a glass material, must be suppressed within ± 0.5%.
It is technically impossible to suppress the capacity accuracy.

In view of the above, Japanese Patent Application Laid-Open No. 60-118642 discloses a glass lens molding die in which a cavity for accommodating excess glass at the time of press molding is provided in the upper inner surface of the barrel die.

Further, in view of the above, Japanese Patent Laid-Open No. 62-128932 discloses that the temperature of each of a pair of molding dies is simultaneously or temporally different from each other, and a glass material is heated and pressed to form two surfaces of a lens. Discloses a method for molding a glass lens, which is to provide a difference in molding speed. Furthermore, Japanese Patent Laid-Open No. 2-1
In view of the above, Japanese Patent No. 64730 discloses that a glass material is heated and deformed under pressure, and during pressurization and cooling, a fluid having a temperature of several degrees Celsius to several tens of degrees Celsius higher than the central temperature of the optical element is caused to flow into the molding die space. An optical element molding die and an optical element molding method for molding an optical element while uniformly adjusting the temperature distribution of the optical element are disclosed.

[0005]

However, the glass lens mold of JP-A-60-118642 and the glass-lens molding method of JP-A-62-128932 are only applicable to a concave lens whose center is thinly recessed. It was applicable and could not be applied to a convex lens with a thick central bulge. More specifically, in the case of a convex lens with a thick central bulge, it is not possible to provide a void in the barrel mold, and even if a void is provided, when incorporating the lens molded product into the lens frame,
There was a problem that remarkable difficulty occurred. In addition, there is a problem in that the diameter of the lens frame or the like is inevitably expanded due to the generation of unnecessary parts in the lens, which violates the demand for small size and light weight.

Further, in the optical element molding die and the optical element molding method disclosed in Japanese Unexamined Patent Publication No. 2-164730, since the material of the lens frame is limited to resin, it is possible to mold a high precision glass lens which is unaffected by the influence of heat change. Was unsuitable. Further, there is a problem that the supply device for supplying the liquefied resin has to be extremely large-scaled.

The present invention has been made in view of the above, and an object of the present invention is to provide a glass lens molding apparatus which can be applied to a convex lens having a thick center and is bulged, and which can ensure a highly accurate wall thickness.

[0008]

In order to achieve the above-mentioned object in the present invention, an upper mold having a first inner lens barrel,
A lower mold provided with a second inner lens barrel and facing the upper mold; and a glass material interposed between the upper mold and the lower mold. In a lens molding method, a surplus glass of a glass material is accommodated in a press portion of the first or second inner lens barrel when the glass lens is molded, and caulking is performed by press contact with the second or first inner lens barrel. It is characterized by the arrangement of a mirror frame that can be used.

In order to achieve the above object, the present invention is characterized in that the lens frame is formed in an annular shape having a substantially L-shaped cross section, and a notch is cut out on the inner peripheral surface of the lens frame which is erected. I am trying.

[0010]

According to the present invention, the excess glass of the glass material is accommodated in the press portion of the first or second inner lens barrel during the molding of the glass lens, and when the glass is pressed into contact with the second or first inner lens barrel. Since the caulking lens frame is provided, it is possible to eliminate the need for severe capacitance accuracy and secure a highly accurate thickness of the convex glass lens.

Further, it becomes possible to eliminate the complicated centering work of the glass lens after molding. Further, since the lens frame is bent and caulked at the time of molding, and the glass lens and the lens frame are integrated, it can be expected that high-precision centering work is unnecessary. Further, the work of assembling the lens frame is not required, so that the manufacturing cost can be suppressed and the defective rate at the time of mass production can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment shown in FIGS. A glass lens molding apparatus according to the present invention includes an upper mold 1 having an upper mold inner lens barrel 2 which is a first inner lens barrel, and a lower mold inner lens barrel 5 which is a second inner lens barrel. The lower mold 4 facing the upper mold and a glass hump 7 which is a glass material interposed between the upper mold 1 and the lower mold 4 are provided, and the upper mold 1 and the lower mold 4 are pressed to project from the glass hump 7. It has a function of molding the glass lens 7A of the mold.

The upper die 1 has a substantially inverted cross section in cross section,
The lower end surface of the hanging part is formed into a cavity surface 1a recessed in a hemispherical shape, and is fitted into a cylindrical upper mold inner lens barrel 2 from above, and this upper mold inner lens barrel 2 is It is vertically movably inserted into the cylindrical outer lens barrel 3 from above. The lower end of the upper mold 1 and the flat lower end of the inner barrel 2 for the upper mold are flush with each other.

The lower mold 4 has a substantially convex cross section, and the upper end surface of the standing upright part is formed into a cavity surface 4a which is recessed in a hemispherical shape.
The lower inner lens barrel 5 for
Is inserted into the outer lens barrel 3 from below. The upper end of the lower mold inner lens barrel 5 is located slightly higher than the upper end of the lower mold 4, and a mounting portion with a larger diameter is cut out around the inner peripheral surface thereof. A lens frame 6 that fits the upper end of the lower mold 4 is detachably arranged in the mounting portion.

As shown in FIGS. 1, 4 and 5, the lens frame 6 is formed in an annular or cylindrical shape having a substantially L-shaped cross section, and its upper end 6a is positioned higher than the upper end of the lower mold inner lens barrel 5. The top surface of the upper end 6a is located so as to project, and is inclined downward from the center of the lens frame 6 toward the outside. Moreover, the lens frame 6
A notch 6b is cut around the upright inner peripheral surface, and the notch 6b and the upper surface of the upper end 6a are bent toward the center of the lens frame 6 as the upper mold inner lens barrel 2 is pressed. The bent portion 6c is crimped and formed. In the present embodiment, the lens frame 6 has a cylindrical body arranged around the lens, and the glass lens is scissored by performing so-called aperture drawing. However, when it is attempted to increase the amount of scissors, if the inner peripheral side of the cylindrical body forming the lens frame 6 may be distorted and wrinkles may be generated, a cut or the like may be made on the peripheral edge in advance. It is also possible to form or form a bent portion.

Further, the glass hump 7 is formed in a substantially spherical shape and is arranged on the cavity surface 4a of the lower mold 4, and is deformed by rolling when the upper mold 1 and the lower mold 4 are pressed to form a convex mold. It is designed to be molded into a glass lens 7A.

Therefore, in order to mold the convex glass lens 7A from the glass hump 7, as shown in FIG. 1, the glass hump 7 is arranged on the cavity surface 4a of the lower mold 4 and the outer lens barrel 3 is arranged from above to the inside of the upper mold. After inserting the lens barrel 2, the upper mold 1 may be lowered toward the lower mold 4 in a heated state.

Then, as shown in FIG. 2, the upper mold 1 is pressed against the glass hump 7 to roll and deform the glass hump 7, and the surplus glass of the glass hump 7 flows into the lens frame 6 surrounding the cavity surface 4a and is accommodated therein. ..

When the lower end of the upper mold inner lens barrel 2 is pressed against the inclined upper end 6a of the lens frame 6, as shown in FIG.
The bending portion 6c of the lens frame 6 is bent and crimped toward the center,
A convex glass lens 7A having a flange on the outer peripheral edge is molded, and the lens frame 6 is integrally attached to the peripheral edge flange of the glass lens 7A. At this time, the bending portion 6c of the lens frame 6 is
An upper end 6a whose upper surface is inclined downward from the center of the lens frame 6 and a notch 6b cut out on the inner peripheral surface allows the upper surface 6a to flex smoothly in the central direction. In this way, the glass lens 7A becomes an integral part of the lens frame 6 and is taken out from the lower mold 4.

According to the above construction, the glass frame 7 is attached to the lens frame 6.
Excess glass of the glass enters and is housed, and this lens frame 6
Since the bending portion 6c of is bent and crimped toward the center,
It is possible to secure a highly accurate wall thickness of the convex glass lens 7A by eliminating the need for severe capacitance accuracy.

Further, when molding a glass lens, a glass bump 7
Since the convex type glass lens 7A is molded from the lens frame 6 and the lens frame 6 is integrally attached to the peripheral flange of the glass lens 7A, the complicated centering work of the glass lens 7A after molding is unnecessary. Is possible. Further, since the lens frame 6 is bent and crimped at the time of molding, it can be expected that highly accurate centering work is unnecessary. Further, the work of assembling the lens frame 6 is unnecessary, the manufacturing cost can be suppressed by reducing the work steps, and the defective rate at the time of mass production can be reduced.

In the above embodiment, the convex glass lens 7A is formed by using the lens frame 6 placed on the lower mold inner lens barrel 5, but the upper mold inner lens barrel 2 is used. It is needless to say that the lens frame 6 may be provided in the above and can be applied to the case of molding the concave glass lens 7A. Further, as shown in FIG. 6, even when the lower end of the upper mold inner lens barrel 2 is curved and inclined from the outer side to the inner side, and the upper end 6a of the lens frame 6 is configured to be flat, the same effect as that of the above embodiment is obtained. Can be expected.

[0023]

As described above, according to the present invention, a surplus glass of a glass material is accommodated in the press portion of the first or second inner lens barrel when the glass lens is molded, and the second or first inner mirror is accommodated. Since the lens frame that is crimped when it is pressed against the barrel is placed, there is a remarkable effect that it is possible to secure the thickness of the highly accurate convex glass lens by eliminating the need for severe capacitance accuracy. ..

Further, there is a remarkable effect that the complicated centering work of the glass lens after molding can be eliminated. Further, since the lens frame is bent and crimped at the time of molding, there is a remarkable effect that highly accurate centering work can be expected to be unnecessary. Furthermore, there is a remarkable effect that the work of assembling the lens frame becomes unnecessary, the manufacturing cost can be suppressed, and the defective rate at the time of mass production can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional explanatory view showing a state immediately before molding of a glass lens molding apparatus according to the present invention.

FIG. 2 is an explanatory sectional view showing a state during molding of the glass lens molding apparatus according to the present invention.

FIG. 3 is a cross-sectional explanatory view showing a state immediately after molding of the glass lens molding apparatus according to the present invention.

FIG. 4 is a perspective view showing a lens frame and a glass lens according to the present invention.

FIG. 5 is a cross-sectional explanatory view showing a lens frame according to the present invention.

FIG. 6 is an explanatory cross-sectional view of a main part showing another embodiment of the glass lens molding apparatus according to the present invention.

[Explanation of symbols]

1 ... Upper mold, 2 ... Upper mold inner lens barrel (first inner lens barrel), 3
... outer lens barrel, 4 ... lower mold, 5 ... lower lens inner lens barrel (second inner lens barrel), 6 ... lens frame, 6a ... upper end of lens frame, 6b ... notch of lens frame, 6c ... lens frame Flexure part, 7 ... Glass bump, 7A
… Glass lens.

Claims (2)

[Claims] 1. An upper mold having a first inner lens barrel, a lower mold having a second inner lens barrel facing the upper mold, and a glass interposed between the upper mold and the lower mold. A glass lens forming apparatus, comprising: a material; and pressing an upper die and a lower die to form a glass lens from a glass material, wherein a glass material is formed at the pressing portion of the first or second inner lens barrel at the time of forming the glass lens. 2. A glass lens forming apparatus, characterized in that a surplus glass is housed therein, and a lens frame that is crimped when being pressed against the second or first inner lens barrel is arranged. 2. The lens frame is formed in a ring shape having a substantially L-shaped cross section,
The glass lens molding apparatus according to claim 1, wherein a cutout is cut out in the upright inner peripheral surface of the lens frame.