JP3134581B2 - Mold for optical element molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding an optical element for producing an optical element used in an optical instrument by molding. More specifically, an object of the present invention is to provide a molding die capable of molding lenses of any shape from biconvex to biconcave with high accuracy.

[0002]

2. Description of the Related Art In recent years, many attempts have been made to form an optical lens by one-shot molding without a polishing step. The most efficient method is to transfer the glass material from a molten state to a mold and press-mold it, but it is difficult to control the shrinkage of the glass during cooling, and it is not suitable for precise lens molding. Therefore, it is a general method to pre-process a glass material into a predetermined shape, supply it into a mold, heat, and press-mold.

In this molding method, it has been found that the point of realizing the precision transfer is maintaining the close contact between the mold and the molded lens during cooling, and the metal which allows the upper and lower molds to slide smoothly during cooling. A mold structure is disclosed (for example, JP-A-2-34526, JP-A-2-1377).
No. 40).

[0004]

Problems to be Solved by the Invention
The mold disclosed in Japanese Patent Application Publication No. 0-2005-086300 has a structure as shown in FIG.
Even if there are flanges 50 ′ and 51 ′ at 0 and 51, the lower mold 51 keeps close contact with the molding material 53 by the voids 54 while contracting the molding material 53 in the cooling process, while maintaining the close contact with the molding material 53.
It has a structure that can slide inside. When molding a biconvex lens using such a mold structure, good molding is possible as disclosed in the above-mentioned publication.

[0005] However, when the biconcave lens 55 is molded in one shot as shown in FIG.
Since the side surface portion 55 ′ is in close contact with the inner wall of the body mold, in order to cool the molding lens 55 on each of the upper and lower transfer surfaces 59 and 60 while maintaining the close contact in the cooling process, the upper and lower dies 5.
Both 7, 58 must be mold structures that can slide as shown by the arrows. However, in the configuration shown in FIG. 5B, the upper mold 57 cannot slide because the flange 57 'is in contact with the upper end surface 56' of the body mold 56. Therefore, the conventional mold structure has a problem that the close contact surface 59 between the upper mold 57 and the molded lens 55 is released during cooling, and good transferability cannot be obtained.

The mold described in Japanese Patent Application Laid-Open No. 2-34526 has a structure as shown in FIG. 6, in which the upper and lower molds 61 and 62 are shrunk together with shrinkage of the molding lens 64 during cooling.
The mold can be slid smoothly inside, and the mold structure is suitable for molding the biconcave lens as described above.

However, the flange 5 shown in FIG.
Since there is no 0 ', the mold cannot be held during the processing of the mold. Therefore, as shown in FIG. 7A, it is necessary to bond another member 82 to the surface of the die that is not processed with an adhesive 83, and to process while holding the outer peripheral portion of the member 82.

When mass-producing a mold by such a processing method, it is difficult to adhere the mold 81 to the member 82 vertically and accurately at all times, and the mold 81 is often inclined as shown in FIG. As shown in FIG. 5D, there are problems that it is difficult to obtain parallelism between the upper and lower surfaces 84 and 85 of the mold 81 after the completion of the processing, and that the number of processing steps increases due to the work of bonding and peeling the holding member. Was.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a pair of upper and lower dies, an inner body die for regulating the positions of the upper and lower dies coaxially, and a center thickness of a molding element. In this case, a means for providing a stepped portion on the inner wall surface at the end of the outer or inner body is provided.

[0010]

By using the present invention, the upper and lower molds can smoothly slide even in a mold having a flange portion, while maintaining the close contact between the molded lens and the mold against shrinkage of the molded lens in the cooling process. It becomes possible to cool. As a result, the molding die according to the present invention can realize a molding die that can be applied to lens molding of any shape from biconvex to biconcave.

[0011]

【Example】

(Embodiment 1) An embodiment according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a state before molding a biconcave lens according to a first embodiment of the present invention, FIG. 2 (a) shows a state immediately after molding, and FIG. 2 (b) shows a state of a mold accompanying shrinkage of a lens in a cooling process. FIG. 7C shows a state after the cooling is completed. 1 is the upper mold,
Reference numeral 2 denotes a lower die, 3 denotes an inner trunk die, 4 denotes an outer trunk die, 5 denotes a molded material, 5 ′ denotes a molded lens, 1 ′ and 2 ′ denote flanges, and 6 denotes a step portion. Reference numerals 10 and 11 denote upper and lower pressure blocks, and 12 denotes a cylinder shaft directly connected to a pressure cylinder (not shown). Hereinafter, the molding process will be described in detail.

The upper and lower dies 1 and 2 and the inner shell 3 were made of a super hard material, and the outer shell 4 was made of a SUS material. First, an SF8 flat glass material having a glass transition temperature of 480 ° C. is set in a mold as shown in FIG. 1 for the molding material 5, and the mold M and the material 5 are heated to near the softening point temperature and then pressure molded. . At this time, as shown in FIG. 2A, the upper press head 10 comes into contact with the upper end surface 4a of the outer barrel die 4 and cannot be further deformed. In this state, the upper and lower dies 1 and 2 are further slidable because the gaps 15 and 16 are secured between the upper and lower dies 1 and 2. The molded lens 5 'is in close contact with the upper and lower mold surfaces 1a and 2a and the inner wall 3a of the body mold.

Thereafter, when the lens is cooled slowly, the molded lens 5 'contracts with the cooling. In order to cool the molded lens 5 ′ while maintaining the close contact between the upper and lower molds 1 and 2 and the molded lens 5 ′ with respect to the contraction of the molded lens 5 ′, the vertical Directional sliding is required.
FIG. 2B shows this state. In a process of cooling, gaps 23 and 24 are temporarily generated between the upper and lower dies 1 and 2 and the upper and lower pressure blocks 10 and 11.

After that, when the cooling further proceeds, the side surface 25 of the molded lens 5 'is released from the inner wall of the barrel mold as shown in FIG. 2C, and the upper mold 1, the molded lens 5' and the lower mold 2 are pressed by the lower press. The air gap 24 disappears after riding on the head 11. Next, the upper press head 10 was raised, and the molded lens taken out of the mold was measured with an interferometer. As a result, good transferability of about λ / 4 was obtained.

(Embodiment 2) FIG. 3 shows one state in a cooling process after forming a biconcave lens in a second embodiment. The configuration of the mold is the same as that of the first embodiment, except that a stepped portion of the outer body mold 4 is eliminated and a cutout 30 is provided at the lower end of the inner body mold 3. The molding method was the same as in Example 1. When deformed under pressure, the upper press head 10 comes into contact with the outer barrel mold 4 and further deformation is not possible. In this state, the upper and lower dies 1 and 2 are
Since 1 and 32 are secured, it is in a slidable state. The subsequent process is the same as in the first embodiment. When the molded lens according to the present embodiment is measured with an interferometer, λ
Good transferability of about / 4 was obtained.

(Embodiment 3) FIG. 4 shows a state in a cooling process after molding a biconcave lens in a third embodiment. The mold has a structure in which notches 41 and 42 are provided at both ends of the inner body die without the outer body die. The molding method was the same as in Example 1. When deformed under pressure,
The upper press head 10 comes into contact with the outer drum 4 and cannot be further deformed. In this state, the upper and lower dies 1 and 2 are further slidable because the gaps 31 and 32 are secured between the upper and lower dies 1 and 2. The subsequent process is the same as in the first embodiment. When the molded lens according to this example was measured with an interferometer, transferability of about λ / 3 was obtained.

[0018]

The mold according to the present invention can smoothly slide both the upper and lower molds even with a mold having a flange. It can be cooled while maintaining the close contact. Therefore, the mold according to the present invention can mold lenses of any shape from biconvex to biconcave with high accuracy and can provide a mold having good workability.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a mold according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a molding process using the mold of the embodiment.

FIG. 3 is a sectional view showing a configuration of a mold according to another embodiment of the present invention.

FIG. 4 is a sectional view showing a configuration of a mold according to still another embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional mold structure.

FIG. 6 is a sectional view showing another conventional mold structure.

FIG. 7 is a cross-sectional view showing a processing step of the mold.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Upper mold 2 Lower mold 1 ', 2' Flange 1a Adhesive surface of upper mold and molded lens 2a Adhesive surface of lower mold and molded lens 3 Inner body 3a Inner body inner wall 4 Outer body 4a Outer body upper End face M Mold 5 Molding material 5 'Molding lens 6 Stepped portion 10, 11 Vertical pressing block 12 Cylinder shaft 15, 16, 23, 24, 31, 32, 42, 43 Air gap 25 Molded lens side portion 30, 41 Inside Notch 41a at the upper and lower end of the torso

Continuation of front page (72) Inventor Daijiro Yoneya 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-6-256025 (JP, A) JP-A-6-9231 (JP) JP-A-2-137740 (JP, A) JP-A-2-34526 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C03B 11/08

Claims (3)

(57) [Claims] 1. An optical element for manufacturing an optical element, comprising a pair of upper and lower molds and a body mold having a flange, and press-molding a raw material supplied into a molding tool comprising the upper and lower molds and the body mold. A molding die, wherein the body mold guides the upper and lower molds coaxially and slidably, and has an end part facing the flange of the upper and lower molds; and And an outer barrel that includes the upper and lower dies guided by the inner barrel, and defines the thickness of the optical element formed by the thickness thereof, and at a step portion provided on the inner wall thereof,
It is composed of an outer body mold that locks and supports the inner body mold at the end of the inner body mold, and a gap is formed between the flange of the upper and lower molds and an end of the inner body mold during molding. A mold for molding an optical element, wherein dimensions of the upper and lower molds, the inner body mold, and the outer body mold are determined so as to remain. 2. An optical element comprising a pair of upper and lower molds and a body mold having a flange, and for press-molding a material supplied into a molding die comprising the upper and lower molds and the body mold to manufacture an optical element. A molding die, wherein the body mold guides the upper and lower molds coaxially and slidably, and has an end part facing the flange of the upper and lower molds; and And an outer barrel that encloses the upper and lower dies guided by the inner barrel, and defines the thickness of the optical element formed by the thickness thereof. A stepped portion that includes the flange of the mold and faces each other is formed, and at the time of molding, the flange of the upper mold and the upper end of the inner mold, and the lower flange of the lower mold and the lower end of the inner mold. The upper and lower molds, so that a gap remains between the step portion of the portion,
A mold for molding an optical element, wherein dimensions of the inner body die and the outer body die are determined. 3. An optical element for manufacturing an optical element, comprising a pair of upper and lower molds and a body mold having a flange, and press-forming a material supplied into a molding tool comprising the upper and lower molds and the body mold. A molding die, wherein the trunk die guides the upper and lower dies slidably coaxially, and is a trunk die that defines the thickness of the optical element to be molded by its thickness; The part is formed with a stepped portion that includes the upper and lower mold flanges and faces each other, and a gap remains between the flange of the upper and lower molds and the stepped part of the body mold during molding. In this manner, the shape and dimensions of the upper and lower molds and the body mold are determined, and the optical element molding mold is thus characterized.