JPH0656437A - Forming of glass raw material for aspherical lens - Google Patents

Abstract

PURPOSE:To obtain a glass raw material at a low cost by reducing the tact-up and man-hour in the processing of a glass raw material and to efficiently produce a high-quality lens by shortening the lead-time to the forming process. CONSTITUTION:In the process to form a press-formed product 13 (the glass raw material subjected to primary processing) from molten glass, the diameter A of a glass raw material 13' is set in the stage of press-formed material 13 and both faces 11, 11' of the press-formed product 13 are processed to transparent state e.g. by polishing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a glass material for an aspherical lens, which comprises molding an aspherical lens used in an optical instrument by a precision glass molding method.

[0002]

2. Description of the Related Art In recent years, many molding methods have been tried to form optical lenses and are in a practical stage. In such a molding method, a mold corresponding to the lens to be obtained and a glass material to be filled in the mold may be manufactured and used for molding.

Generally, a glass material to be filled in a molding die is produced from molten glass by means of press molding or the like (glass material for primary processing), and is finally (desirably) required. The shape is almost similar to the shape of, but the outer diameter (diameter) and the cutting allowance of the thickness are large, and the surface is rough and opaque. Therefore, the thickness allowance is ground by polishing so that a spherical lens is manufactured, and the removal allowance of the outer diameter (diameter) is worked by a centering machine and is ground so as to be axially symmetric. The glass material required for) is manufactured.

However, little is known about a method of processing a glass material used for an aspherical molded lens.

A conventional method for molding a glass material for an aspherical molded lens will be described below. FIG. 2 (a) shows a press-molded product E (glass material for primary processing) from a conventional molten glass.
The glass material 3 ', which has a shape similar to that of the glass material 3'which is finally (desirably) required, is formed, the surface 2 is covered with a rough and opaque active surface, and A is the thickness of the glass material. B is the outer diameter (diameter) of the glass material 3, E and F
Is formed with a cutting margin for obtaining the desired glass material 3 '.

Since the entire surface of the glass material formed as described above is a rough and opaque active surface, the thickness C is A
Surface 2 is ground by polishing until
And the surface shape. The surface 2 is ground to a state where the outer diameter is B using a centering machine, and the processing of the desired glass material 3'is completed by the method of manufacturing a spherical lens.

The glass material 3'in the above state is shown in FIG.
As shown in (b), the glass material 3 is filled in the molding die constituted by the upper die 4, the lower die 5, and the body die 6 of the aspherical lens molding die, and the desired performance is obtained. The spherical lens 3'can be obtained stably.

[0008]

However, in FIG. 2, the desired shape of the glass material 3'is finally required from the molten glass by the press-molded product 3 (glass material for primary processing) as described above. The thickness E and the outer diameter (diameter) F are larger than the glass material 3'by the cutting allowance, so that the following problems occur. (1) In order to obtain the desired shape of the glass material 3 ', a polishing step and a centering step are required to manufacture a spherical lens, which results in an expensive glass material 3'. (2) The lead time (manufacturing process) until the desired glass material 3 ′ is obtained is from molten glass to press-molded product E →
Polishing process → Washing → Centering process → Washing → Finishing desired glass →
Due to the long process such as the molding work of the aspherical molded lens, a large amount of the glass material 3'is required to be in stock. (3) Since the glass material 3'has no anti-reflective film like the finished lens, it is difficult to store it because the surface of the glass material is prone to chemical deterioration when the stock period is long and it is necessary to cause burns and the like. .

In view of the above-mentioned conventional problems, it is an object of the present invention to obtain a desired glass material inexpensively and surely and shorten the lead time to improve the work efficiency.

[0010]

In order to solve the above problems, the present invention is to press a glass material from a molten glass state by press molding using a molding die whose diameter dimension is set to a first dimension. , The diameter of the glass material is set to the first dimension, and the glass material is molded to have a diameter dimension that does not require subsequent processing, and the entire glass material is processed to the desired dimension, and the front and back surfaces of the glass material are transparent. It is processed to become.

[0011]

According to the present invention having such characteristics, the surface of the molten glass, which is formed into a shape substantially similar to the shape of the final glass material by the press-molded product (the glass material of the primary processing), is rough. In the case of opaque glass materials, both of these glass materials can be processed by setting the outer diameter of the glass material that is finally required at the stage of the press-molded product (the glass material of the primary processing). It becomes only the side of, and the centering work can be unnecessary.

When this glass material is filled in a molding die and pressure-molded, the lens to be molded has a desired optical effective diameter and lens outer diameter.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the construction of a molding die used for manufacturing a glass material and a lens according to an embodiment of the present invention.

Also in this embodiment, the press-molded product F (glass material for primary processing) from molten glass shows a shape substantially similar to the glass material 13 'that is finally required, and the surface 11 is rough. The fact that it is covered with an opaque active surface is the same as in the conventional example described above.

In the present embodiment, the press-formed product (1
Subsequent processing glass material 13 thickness A, glass material 13 '
The relationship between the outer diameter (diameter) B and the cutting allowance E will be described in detail below.

In FIG. 1A, the desired glass material 1
The surface shapes machined to a thickness A to obtain 3'are indicated by 11 and 11 ', and B is a molten glass press-formed product 13
Since the outer diameter B (diameter) of the glass material finally required at the stage of (primary processing glass material) is set in advance at the time of the press-molded product 13, the desired glass material 1
The outer diameter (diameter) of 3'is shown. E indicates the range of the cutting margin for obtaining both surface shapes 11 and 11 'of the desired glass material 13'.

As shown in FIG. 1 (b), the glass material 13 'in the above-described state is formed in the upper mold 14, the lower mold 15, and the body mold 16 in the upper mold 13 and the lower mold 14. And then press-molded so that the aspherical lens 17 having desired performance can be stably obtained.

In the present invention, a press-molded article 1 made of molten glass is used.
By setting the outer diameter (diameter) B of the glass material 13 'finally required at the stage of 3 (glass material for primary processing) in advance at the time of press-molded product 13, after the grinding work of E, It doesn't require the work of taking care. That is, by obtaining both surfaces 11, 11 ', the desired glass material 13'
Can be completed.

Next, the relationship between the glass material according to the present embodiment and the aspherical molded lens produced from the glass material will be described.

Here, the desired lens volume is 269.06 mm ³
And the lens center thickness is t2.8 mm, and the lens optical effective diameter is φ.
When trying to obtain an aspherical lens having an lens outer diameter of 11.78 mm and a lens outer diameter of φ13.0 mm, the glass material 13 ′ to be filled needs to be estimated larger than the desired lens. For example, the center thickness A is t3.50 mm and the outer diameter is Diameter B is φ12.8 mm, 1
The curvatures of 1 and 11 'are R = 14.559 mm and R =
If the size is 29.411 mm, the volume of the glass material 13 'is 31.
The desired glass material 13 'is set so that the desired lens shape is obtained with 1.557 mm ³ . After setting the shape in this way, in order to obtain the desired glass material 13 ', it is necessary to make the shape of the press-formed product 13 (the glass material for the primary processing) from the molten glass larger than that of the glass material 13'.
Temporarily increase the center thickness A by 0.5 mm for each piece and t4.5
Assuming that the outer diameter and the curvature are the same as those of the desired glass material 13 ', the cutting allowance E is 11 to obtain the desired glass 13'.
By polishing to positions 11 and 11 ', the desired transparent glass material 13' is completed.

The above glass material 13 'is applied to the upper mold 14,
The biconvex aspherical lens 17 filled in the molding die composed of the lower die 15 and the body die 16 and press-molded was able to obtain desired performance and be stably manufactured.

[0023]

As described in detail above, according to the present invention, the desired outer diameter (diameter) dimension of the glass material is preset in the stage of the above-mentioned molten glass into a press-molded product (glass material for primary processing). By setting it at the time of press-molded products (glass material for primary processing), there is no need to process the outer diameter (diameter), and at the same time the capital investment of the centering machine becomes unnecessary and the number of processing steps for the desired glass material It is possible to obtain a less expensive glass material and shorten the lead time to improve work efficiency.

[Brief description of drawings]

FIG. 1 (a) is a sectional view showing a constitution of a method for molding a glass material of an aspherical molded lens according to an embodiment of the present invention (b) a sectional view showing a constitution of a molding die in the same embodiment.

FIG. 2A is a cross-sectional view showing a configuration of a method for molding a glass material of an aspherical molded lens according to a conventional example. FIG. 2B is a cross-sectional view showing a configuration of a molding die in the same example.

[Explanation of symbols]

 11 surface shape 11 'surface shape 13 press-formed product 13' desired glass material

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masayuki Itagaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A glass material is press-molded from a molten glass state using a molding die whose diameter dimension is set to the first dimension, and the diameter dimension is set to the first dimension, and , Characterized in that the glass material is formed into a diameter dimension that does not require subsequent processing, the entire glass material is processed into desired dimensions, and the front and back surfaces of the glass material are processed to be transparent. Molding method for glass material of spherical molded lens.