JP3161622B2 - Glass lens molding equipment - Google Patents

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 an optical instrument 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 manufacturing cost reduction, and it is generally desired that the wall thickness be within ± 0.03 mm. ing. In order to satisfy this requirement, it is necessary to at least suppress the capacitance accuracy of the glass material, which is a glass material, to within ± 0.5%.
It is technically impossible to suppress the capacitance accuracy.

[0003] In view of the above, Japanese Patent Application Laid-Open No. Sho 60-118642 discloses a mold for a glass lens in which a cavity for accommodating surplus glass during press molding is provided in the upper inner surface of a barrel mold.

In view of the above, Japanese Patent Application Laid-Open No. Sho 62-128932 considers the above and sets the temperature of each of a pair of molds simultaneously or temporally, heats and presses a glass material, and presses the two surfaces of the lens. Discloses a method of forming a glass lens in which a difference is made in the forming speed of the glass lens. Further, Japanese Patent Laid-Open No. 2-1
In view of the above, Japanese Patent No. 64730 discloses that a fluid having a temperature several degrees to several tens degrees higher than the center temperature of an optical element flows into a mold space while a glass material is heated and deformed under pressure and further cooled under pressure. Discloses 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.

[0005]

However, the method of molding a glass lens disclosed in Japanese Patent Application Laid-Open No. Sho 60-118642 and the method of molding a glass lens disclosed in Japanese Patent Application Laid-Open No. Sho 62-128932 only apply to a concave lens whose center is thinly concave. It was applicable, and could not be applied to convex lenses with thick central bulges. More specifically, in the case of a convex lens whose center is thick and bulged, a cavity cannot be provided in the body mold.
There is a problem that remarkable difficulty occurs. Further, there is a problem in that unnecessary portions are generated in the lens, so that the diameter of the lens frame or the like is inevitably expanded, which contradicts the demand for small size and light weight.

In the optical element molding die and the optical element molding method disclosed in Japanese Patent Application Laid-Open No. 2-164730, the material of the lens frame is limited to resin. Was unsuitable. Further, there is a problem that the supply device for supplying the liquefied resin must be extremely large.

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

[0008]

According to the present invention, in order to achieve the above-mentioned object, an upper mold having a first inner barrel is provided.
A lower mold having a second inner lens barrel and facing the upper mold; and a glass material interposed between the upper mold and the lower mold. In molding a lens, an excess glass of a glass material is accommodated in a press portion of the first or second inner lens barrel at the time of molding a glass lens, and caulked with pressure contact with the second or first inner lens barrel. It is characterized in that a mirror frame is arranged.

Further, in the present invention, in order to achieve the above object, the lens frame is formed in a ring shape having a substantially L-shaped cross section, and a cutout is cut out in an upright inner peripheral surface of the lens frame. And

[0010]

According to the present invention, the surplus glass of the glass material is accommodated in the press portion of the first or second inner barrel at the time of molding the glass lens, and the pressurization with the second or first inner barrel is performed. Since the crimped mirror frame is provided, it is possible to secure the thickness of the highly accurate convex glass lens by eliminating the requirement for severe capacity accuracy.

In addition, it is possible to eliminate the need for complicated work of centering the glass lens after molding. Then, since the lens frame is bent and crimped during molding, and the glass lens and the lens frame are integrated, it can be expected that high-precision centering work becomes unnecessary. Furthermore, the work of assembling the lens frame becomes unnecessary, so that the manufacturing cost can be suppressed and the defect rate during mass production can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to one embodiment shown in FIGS. The glass lens forming apparatus according to the present invention includes an upper die 1 having an upper inner lens barrel 2 as a first inner lens barrel, and a lower inner lens barrel 5 as a second inner lens barrel. A lower mold 4 facing the upper mold and a glass bump 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 bump 7. It has a function of molding the mold glass lens 7A.

The upper mold 1 has a substantially inverted convex cross section.
The lower end surface of the hanging part is formed in the cavity surface 1a concaved in a hemisphere shape, and is fitted to the cylindrical upper mold inner lens barrel 2 from above, and the upper mold inner lens barrel 2 is It is inserted into the cylindrical outer lens barrel 3 so as to be vertically movable 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 at the same position.

The lower mold 4 is formed to have a substantially convex cross section, and an upper end surface of an upright standing portion is formed in a cavity surface 4a which is concave in a hemispherical shape.
The lower lens barrel 5 is fitted from below.
Is inserted into the outer lens barrel 3 from below. The upper end of the inner barrel 5 for the lower die projects slightly higher than the upper end of the lower die 4, and a mounting portion with an enlarged diameter is cut out around the inner peripheral surface thereof. A mirror frame 6 through which the upper end of the lower mold 4 is inserted is detachably disposed on 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 located higher than the upper end of the inner barrel 5 for the lower die. In addition to being protruded, the upper surface of the upper end 6 a is inclined downward and outward from the center of the lens frame 6. Mirror frame 6
A cut 6b is cut out around the raised inner peripheral surface, and a portion from the cut 6b to the upper surface of the upper end 6a is bent toward the center of the lens frame 6 with the press-contact of the inner barrel 2 for the upper die. It is formed on the bent portion 6c which is crimped. In this embodiment, the lens barrel 6 is provided with a cylindrical body around the lens, and is subjected to so-called aperture drawing to scissor the glass lens. However, when trying to increase the amount of scissors, if there is a possibility that the inner peripheral side of the cylindrical body forming the lens frame 6 may be distorted and wrinkles may be generated, the peripheral edge may be appropriately cut in advance. You may put or bend and may form it.

Further, the glass bump 7 is formed in a substantially spherical shape and is arranged on the cavity surface 4a of the lower mold 4, and is rolled and deformed by pressing of the upper mold 1 and the lower mold 4 to form a convex mold. It is formed into a glass lens 7A.

Therefore, in order to form a convex glass lens 7A from the glass knob 7, as shown in FIG. 1, the glass knob 7 is disposed on the cavity surface 4a of the lower die 4, and the inner lens for the upper die is placed on the outer lens barrel 3 from above. 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 cob 7 to deform the glass cob 7 by rolling, and the surplus glass of the glass cob 7 flows into the mirror frame 6 surrounding the cavity surface 4a and is accommodated therein. .

When the lower end of the upper mold inner 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 in the center direction and caulked,
A convex glass lens 7A having a flange on an outer peripheral edge is formed, and a lens frame 6 is integrally and tightly attached to the peripheral flange of the glass lens 7A. At this time, the bending portion 6c of the lens frame 6
The upper surface 6a whose upper surface is inclined downward and outward from the center of the lens frame 6 and the cut 6b cut out on the inner peripheral surface smoothly bend in the center direction. Thus, the glass lens 7 </ b> A is taken out of the lower mold 4 as an integral part of the lens frame 6.

According to the above configuration, the glass frame 7 is attached to the lens frame 6.
Surplus glass enters and is accommodated, and moreover, this mirror frame 6
Is bent in the center direction and caulked,
It is possible to secure the thickness of the highly accurate convex glass lens 7A by eliminating the need for severe capacitance accuracy.

Also, when molding a glass lens,
Since the convex glass lens 7A is molded from the lens and the lens frame 6 is integrally tightly attached to the peripheral flange of the glass lens 7A, it is not necessary to perform complicated centering work of the glass lens 7A after molding. Becomes possible. Since the lens frame 6 is bent and caulked during molding, it can be expected that high-precision centering work is not required. Further, the work of assembling the lens frame 6 becomes unnecessary, so that the manufacturing cost can be suppressed through a reduction in the number of working steps, and the defect rate during mass production can be reduced.

In the above-described embodiment, the case in which the convex glass lens 7A is formed using the lens frame 6 mounted on the inner lens barrel 5 for the lower die has been described. It is needless to say that the lens frame 6 may be provided in the lens unit, and the present invention is also applicable to the case where the concave glass lens 7A is formed. As shown in FIG. 6, even when the lower end of the upper mold inner barrel 2 is curved and inclined from the outside to the inside, and the upper end 6a of the lens frame 6 is flat, the same operation and effect as in the above embodiment can be obtained. Can be expected.

[0023]

As described above, according to the present invention, the surplus glass of the glass material is accommodated in the press portion of the first or second inner lens barrel at the time of molding the glass lens, and the second or first inner mirror is formed. The remarkable effect is that the lens frame that is swaged in accordance with the pressure contact with the body is arranged, so that it is possible to secure the thickness of the high-precision convex glass lens by eliminating the need for severe capacity accuracy. .

Further, there is a remarkable effect that it is possible to eliminate the need for complicated glass lens centering work after molding. Since the lens frame is bent and caulked during molding, there is a remarkable effect that high-precision centering work can be expected to be unnecessary. Further, there is a remarkable effect that the work of assembling the lens frame becomes unnecessary, the production cost can be suppressed, and the defect rate at the time of mass production can be reduced.

[Brief description of the drawings]

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

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

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

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

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

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

[Explanation of symbols]

1 upper mold 2 inner mold barrel for upper mold (first inner barrel) 3
... Outer lens barrel, 4 ... Lower die, 5 ... Lower inner lens barrel (second inner lens barrel), 6 ... Mirror frame, 6a ... Top of lens frame, 6b ... Cut of lens frame, 6c ... Mirror frame Bending part, 7 ... glass bump, 7A
... a glass lens.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C03B 11/14 C03B 11/08

Claims (2)

(57) [Claims] An upper mold having a first inner barrel, a lower mold having a second inner barrel facing the upper mold, and glass interposed between the upper mold and the lower mold. In a glass lens forming apparatus for forming a glass lens from a glass material by pressing an upper mold and a lower mold, a pressing part of the first or second inner lens barrel is provided with a glass material at the time of forming the glass lens. A lens frame for accommodating surplus glass and being caulked in press contact with the second or first inner lens barrel. 2. The lens frame according to claim 1, wherein said lens frame is formed in an annular shape having a substantially L-shaped cross section.
2. The glass lens forming apparatus according to claim 1, wherein a notch is cut in an upright inner peripheral surface of the lens frame.