JPH08133764A - Production of glass press lens - Google Patents

Abstract

PURPOSE: To provide a producing method of a glass lens, which is dispensed with a centering and edging process and an optical axis adjusting process at the time of incorporating in a lens-barrel or assembling a cemented lens and capable of easily and high precisely assembling. CONSTITUTION: The glass press lens is produced by using a metallic mold for glass press lens having two faces of a positioning reference surface in the parallel direction to optical axis and a positioning reference surface in the vertical direction to optical axis on an effective diameter outer periphery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a glass press lens in which a glass material is softened by heating and pressure-molded into a desired shape with a molding die, and particularly, a centering step is not required after the molding, and a lens mirror is used. The present invention relates to a method for manufacturing a glass press lens that can be easily incorporated into a body with high precision.

[0002]

2. Description of the Related Art A method of manufacturing a lens by precision pressing of glass is generally a process of forming an effective diameter by molding, performing centering for incorporation into a lens barrel, coating an effective diameter, and assembling into the lens barrel. It consists of

In the centering step among the above steps, many attempts have been made to form the lens into the lens barrel as a standard for incorporation into the lens barrel at the time of molding, and to perform the above step simultaneously (for example, Jikken 4). -329, JP-A-60-115905, JP-A-1-145340.
Japanese Patent Laid-Open No. 2-175621, Japanese Patent Laid-Open No. 3-1
77322, JP-A-61-183135,
JP-A-62-78122, JP-A-61-2429
21, JP-A-2-239125, JP-A-6-
3-297233, JP-A-1-183611, JP-A-1-183622, etc.).

Japanese Utility Model Publication No. 4-329 and Japanese Patent Laid-Open No. 60
Japanese Patent Laid-Open No. 115905 discloses a technique of positioning a lens on a lens barrel by using a taper outside the effective diameter. However, in this technique, the parallel eccentricity can be suppressed because the taper 1 surface is used for positioning, but the tilt eccentricity cannot be suppressed.

Although the techniques disclosed in the other publications described above do not require centering, they do not disclose a lens manufacturing method capable of accurately suppressing parallel eccentricity and tilt eccentricity.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and requires no centering step and no optical axis adjustment step in assembling into a lens barrel. An object of the present invention is to provide a method for manufacturing a glass lens that can achieve highly accurate assembly.

[0007]

That is, the present invention provides a mold for a glass press lens which has, on the outer circumference of the effective diameter, a positioning reference surface parallel to the optical axis and a positioning reference surface perpendicular to the optical axis. It relates to a method for manufacturing a glass press lens, which is characterized by being used.

The present invention also provides a mold for a glass press lens, which has, on the outer circumference of the effective diameter, two surfaces, a positioning reference surface parallel to the optical axis and a positioning reference surface perpendicular to the optical axis. .

By simultaneously forming the reference surface for incorporation into the lens barrel on the outer circumference of the effective diameter of the lens together with the effective diameter, the centering step becomes unnecessary.

Further, by forming the positioning reference plane parallel to the optical axis and the positioning reference plane perpendicular to the optical axis on the outer circumference of the effective diameter of the lens at the same time as the effective diameter, the lens can be incorporated into the lens barrel. As a result, a complicated optical axis adjustment process is unnecessary, and highly accurate assembly can be easily achieved.

In particular, when manufacturing a lens in which at least one surface of the effective diameter is an aspherical surface, eccentricity error (centering error, outer diameter deviation) in the centering process is not included, and highly accurate assembly into the lens barrel is achieved. it can.

The present invention will be described below with reference to the drawings.

Example 1 FIG. 1 shows a schematic sectional structure of an example of a glass press mold of the present invention. This glass press mold comprises a mold (2) and a mold (3) facing the mold (2). Both dies may be constructed using materials such as ceramics, cemented carbides and metals.

Both surfaces of the mold (2) and the mold (3) having an effective diameter may be spherical, or at least one surface may be aspherical. In the present invention, the effective diameter means the surface having the optical performance required from the optical design and its diameter.

On the outer circumference of the effective diameter of the mold (2), there are shown a positioning reference plane (a conical surface having an inclination α coaxial with the optical axis and a width of 1 mm) parallel to the optical axis shown in (2a) and (2b). Positioning reference plane in the direction perpendicular to the optical axis (slope β coaxial with the vertical axis of the optical axis,
The conical surface with a width of 1 mm) is processed with high precision by an ultra-precision cutting machine coaxial with the effective diameter. These two surfaces may be formed simultaneously or separately. From the viewpoint of improving the accuracy of coaxial machining of the effective diameter and the reference surface, it is preferable to form them at the same time.

The inclinations α and β of the reference plane are 0 ° to 10 °, respectively.
By setting the angle in the range of 5 °, preferably 5 ° or less, the desired highly accurate incorporation can be achieved. Specifically, when each of the reference surfaces is a conical surface with an inclination of 10 ° or less, the parallel eccentricity at the time of assembling can be suppressed to 10 to 25 μm, which is 1/2 to 2 of the parallel eccentricity at the time of conventional centering processing. A high accuracy of / 3 can be achieved. In a specific embodiment, α = 1 °, β
= 1 °.

The width of both reference surfaces is set to 1 mm in order to ensure the minimum necessary width for incorporating the lens barrel in consideration of the heat shrinkage of the glass after molding. It can be appropriately set according to the shape. By the way, the effective diameter (surface shape, diameter) and the reference surface (surface shape, diameter) in the processing of the mold and the fitting member are all corrected values in consideration of the heat shrinkage of the glass after molding.

Molten glass SF6 (glass transition point Tg = 4
The molding step will be specifically described using 50 ° C.). The molds (2) and (3) are heated to a predetermined temperature (380 ° C.) below Tg by a heating means (not shown). next,
2 g of molten glass previously melted at 900 ° C. is dropped into a mold (3) and supplied. Glass surface temperature is Tg or lower (400 ° C), glass internal temperature is Tg or higher (500 ° C)
After cooling to a predetermined temperature, press molding is performed with the mold (2).
At this time, by molding in a nitrogen atmosphere, the reaction between the mold and the glass is suppressed, and a lens of good quality is obtained.

A schematic sectional shape of the lens thus obtained is shown in FIG. On the outer circumference of the effective diameter of the obtained molded lens (1), a positioning reference plane (1a) parallel to the optical axis (a conical surface having an inclination of 1 ° coaxial with the optical axis and a width of 0.5 mm) and a direction perpendicular to the optical axis The reference plane for positioning (a conical surface having an inclination of 1 ° and a width of 0.5 mm coaxial with the vertical axis of the optical axis) is formed simultaneously with the effective diameter.

The edge portion has a free shape. In this way, the outer peripheral edge portion of the glass is not regulated on the entire surface and is partially free to make an escape, and the glass is thermally cooled at the moment when the molten glass comes into contact with the mold, so that the glass is thermally contracted, so that the mold release can be easily performed.

Further, the positioning reference area of the lens is smaller than the reference area of the mold because the glass after molding is thermally shrunk, but it can be incorporated if a ring zone having a width of 0.3 mm or more is formed.

Next, a method of incorporating the lens into the lens barrel will be described with reference to FIG. Support members (4a) and (4b) are formed on the support member integrated with the lens barrel (4).

The supporting projection (4) parallel to the optical axis of the supporting member.
A) and a reference surface (1a) parallel to the optical axis of the lens are brought into contact with each other to perform positioning and suppress parallel eccentricity.

At the same time, the supporting portion (4b) in the direction perpendicular to the optical axis of the supporting member and the reference surface (1b) in the direction perpendicular to the optical axis of the lens are brought into contact with each other to perform positioning and suppress the tilt eccentricity.
In this state, the supporting member of the lens barrel and the lens are bonded and fixed.
Adhesion and fixing can be performed, for example, by adhesion using an ultraviolet curable resin or epoxy resin or fixing by screwing using a retaining ring.

According to the above assembling method, it is not necessary to strictly adjust the optical axis when assembling into the lens barrel, and the lens can be easily incorporated with high precision. Since the reference surface to be incorporated into the lens barrel is formed outside the effective diameter of the lens at the same time as the effective diameter, the centering step is not required.

[0025]

[Embodiment 2] FIG. 4 shows a schematic cross-sectional structure of an example of a glass press mold according to another embodiment of the present invention. This glass press mold comprises a mold (6), a mold (7) and a fitting member (8) facing the mold (6). Both molds may be made of a material such as ceramic, cemented carbide, metal, etc., and the fitting member is made of the same material as the mold, that is, ceramic, cemented carbide,
A metal or the like can be used, and preferably the same material as the mold is used.

The die (6) has an effective diameter and a cylindrical surface (6a) in the direction parallel to the optical axis which are simultaneously machined by an ultra-precision cutting machine. Of course, they may be machined separately, but they are preferably machined simultaneously to improve the accuracy of coaxial machining of the effective diameter and the reference plane.

The reference plane parallel to the optical axis is not limited to the cylindrical surface (6a) but may be a conical surface. In this case, it is coaxial with the optical axis and the inclination α'is in the range of 0 ° to 10 °, preferably 5 °.
If the following settings are made, the desired highly accurate incorporation can be achieved as well. When the inclination is 0 °, the cylindrical surface (6a) is formed.

In the fitting member (8), a positioning reference plane ((6a) fitted in a direction parallel to the optical axis shown in (8a) and having a width of 1 mm coaxial with the optical axis) and (8b). The positioning reference plane (a ring-shaped flat surface having a width of 1 mm perpendicular to the optical axis) shown in (1) is machined with high precision by the ultra-precision cutting machine. These reference planes may be machined separately, but it is preferable to machine them simultaneously from the viewpoint of improving the accuracy of coaxial machining of the effective diameter and the reference plane.

The width of both reference planes was set to 1 mm, but this is to ensure the minimum necessary width for incorporating the lens barrel in consideration of the heat shrinkage of the glass after molding. It can be set as appropriate.

Further, the positioning reference plane perpendicular to the optical axis shown in (8b) may be a conical surface, in which case the inclination of the optical axis after the fitting member (8) is attached is coaxial with the vertical axis. If β'is set in the range of 0 ° to 10 °, preferably 5 ° or less, the desired highly accurate incorporation can be achieved as well.
When the inclination is 0 °, it becomes a ring-shaped plane perpendicular to the optical axis.

For the combination of the mold and the fitting member, the reference surface (6a) parallel to the optical axis of the mold and the reference surface (8a) parallel to the optical axis of the fitting member are brought into contact with each other or screwed or This can be done by fixing with a retaining ring, and the coaxiality between the fitting member reference surface and the effective die diameter is achieved.

Molten glass SK5 (glass transition point Tg = 6
The molding step will be specifically described using 50 ° C.). The molds (6) and (7) are heated to a predetermined temperature (600 ° C.) below Tg by a heating means (not shown). next,
2 g of molten glass which has been previously melted at 1300 ° C. is dropped into a mold (7) and supplied. Glass surface temperature is Tg or lower (630 ° C), glass internal temperature is Tg or higher (700 ° C)
After being cooled to a predetermined temperature of No. 1, press molding is performed with a mold (6).
At this time, by molding in a nitrogen atmosphere, the reaction between the mold and the glass is suppressed, and a lens of good quality is obtained.

FIG. 5 shows a schematic sectional shape of the lens thus obtained. On the outer circumference of the effective diameter of the obtained molded lens (5), a positioning reference plane (5a) parallel to the optical axis (a cylindrical surface having a width of 0.5 mm coaxial with the optical axis) and a positioning reference plane perpendicular to the optical axis ( 5b) (a ring-shaped plane having a vertical width of the optical axis of 0.5 mm) is formed simultaneously with the effective diameter.

The edge portion has a free shape. In this way, the outer peripheral edge portion of the glass is not regulated on the entire surface and is partially free to make an escape, and the glass is thermally cooled at the moment when the molten glass comes into contact with the mold, so that the glass is thermally contracted, so that the mold release can be easily performed.

Further, the reference positioning area of the lens is smaller than the reference area of the mold because the molded glass undergoes heat shrinkage, but it can be incorporated if a ring zone having a width of 0.3 mm or more is formed.

Next, a method of incorporating the lens into the lens barrel will be described with reference to FIG. Support members (9a) and (9b) are formed on the support member integrated with the lens barrel (9).

The supporting projection (9) parallel to the optical axis of the supporting member.
A) and a reference surface (5a) parallel to the optical axis of the lens are brought into contact with each other to perform positioning and suppress parallel eccentricity.

At the same time, the supporting portion (9b) in the direction perpendicular to the optical axis of the supporting member and the reference surface (5b) in the direction perpendicular to the optical axis of the lens are brought into contact with each other to perform positioning and suppress the tilt eccentricity.
In this state, the supporting member of the lens barrel and the lens are bonded and fixed.
Adhesion and fixing can be performed, for example, by adhesion using an ultraviolet curable resin or epoxy resin or fixing by screwing using a retaining ring.

According to the above-mentioned assembling method, it is not necessary to strictly adjust the optical axis at the time of assembling into the lens barrel, and the lens can be easily incorporated with high precision. Specifically, parallel eccentricity 10-2
With a thickness of 5 μm, 1/2 to 2/3 of that during centering can be achieved. Since the reference surface to be incorporated into the lens barrel is formed outside the effective diameter of the lens at the same time as the effective diameter, the centering step is not required.

[0040]

Third Embodiment The present invention can be applied not only to the lens barrel but also to the cemented lens. FIG. 7 shows a schematic sectional view of the cemented lens.

The lens (10) is manufactured by polishing and grinding, and a cylindrical surface (10) coaxial with the optical axis is formed on the outer circumference of the effective diameter of the cemented surface.
a) and a supporting convex portion (10b) perpendicular to the optical axis are formed at the same time. The cylindrical surface (10a) may be a conical surface. In that case, the inclination δ is coaxial with the optical axis and is 0 to 10 °, preferably 0.
~ 5 °. The case of δ = 0 ° represents the cylindrical surface (10a). The lens (11) is a molded lens according to the present invention.

FIG. 8 shows a schematic sectional structure of an example of a glass press mold for producing the lens (11).

On the outer circumference of the effective diameter of the die (12), (12
a) a positioning reference plane parallel to the optical axis (a cylindrical surface having a width of 1 mm coaxial with the optical axis) and (12b) a positioning reference plane perpendicular to the optical axis (coaxial with the vertical axis of the optical axis, Slope γ
= 1 °, a cylindrical surface with a width of 1 mm) is processed with high precision by an ultra-precision cutting machine coaxial with the effective diameter.

The reference surface (12a) is not limited to a cylindrical surface and may be a conical surface. In this case, the reference surface (12a) is coaxial with the optical axis so that it can be fitted to the reference surface (10a) of the lens (10). Make an angle. The case of δ = 0 ° is the cylindrical surface (12a).

Although the inclination γ is set to 1 °, it may be set to 0 to 10 °, preferably 0 to 5 °.

The width of both reference surfaces was set to 1 mm, but this is to ensure the minimum required width for incorporating the lens barrel in consideration of the heat shrinkage of the glass after molding. It can be appropriately set according to

Molten glass LaF71 (glass transition point Tg
= 630 ° C.), the molding process will be specifically described. The molds (12) and (13) are heated to a predetermined temperature (580 ° C.) below Tg by a heating means (not shown).
Next, 2 g of molten glass that has been previously melted at 1250 ° C
Is dripped into the mold (13) and supplied. The glass surface temperature is Tg or lower (600 ° C), and the glass internal temperature is Tg or higher (6
After cooling to a predetermined temperature of 80 ° C., press molding is performed with a mold (12). At this time, by molding in a nitrogen atmosphere,
The reaction between the mold and the glass is suppressed, and a good quality lens is obtained.

A joint reference surface (11a) parallel to the optical axis and a reference reference surface (11b) perpendicular to the optical axis are simultaneously formed on the cemented surface of the outer periphery of the effective diameter of the obtained lens (11).

The edge portion has a free shape. In this way, the outer peripheral edge portion of the glass is not regulated on the entire surface and is partially free to make an escape, and the glass is thermally cooled at the moment when the molten glass comes into contact with the mold, so that the glass is thermally contracted, so that the mold release can be easily performed.

Next, a method of incorporating the cemented lens will be described with reference to FIG. Cylindrical surface of lens (10) (10
A) and the reference surface (11a) of the lens (11) are brought into contact with each other to perform positioning and suppress parallel eccentricity.

At the same time, the support member (10b) perpendicular to the optical axis of the lens (10) and the reference plane (11) of the lens (11).
Positioning is performed by abutting b), and tilt eccentricity is suppressed. In this state, the supporting member of the lens barrel and the lens are bonded and fixed. Adhesion and fixing can be performed by, for example, adhesion using an ultraviolet curable resin or an epoxy resin, or fixing by screwing using a retaining ring.

According to the above assembling method, the cemented lens can be easily incorporated without requiring strict optical axis adjustment.

[0053]

According to the present invention, the centering step is unnecessary by forming the reference surface to be incorporated into the lens barrel simultaneously with the effective diameter on the outer circumference of the effective diameter of the lens.

Further, by forming two surfaces, a positioning reference plane parallel to the optical axis and a positioning reference plane perpendicular to the optical axis, on the outer circumference of the effective diameter of the lens at the same time as the effective diameter, the lens is incorporated in the lens barrel. As a result, a complicated optical axis adjustment process is unnecessary, and highly accurate assembly can be easily achieved.

In particular, when manufacturing a lens in which at least one surface of the effective diameter is an aspherical surface, eccentricity error (centering error, outer diameter deviation) in the centering process is not included, and highly accurate assembly into the lens barrel is achieved. it can.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a glass press mold of the present invention.

FIG. 2 is a diagram showing a schematic cross-sectional shape of a glass press lens obtained by the mold of FIG.

FIG. 3 is a diagram for explaining a method of incorporating a lens into a lens barrel.

FIG. 4 is a schematic sectional view of another glass press mold of the present invention.

5 is a diagram showing a schematic cross-sectional shape of a glass press lens obtained by the mold of FIG.

FIG. 6 is a diagram for explaining a method of incorporating a lens into a lens barrel.

FIG. 7 shows a schematic cross-sectional view of a cemented lens.

FIG. 8 is a schematic sectional view of another glass press mold of the present invention.

[Explanation of symbols]

1: Lens, 1a: Positioning reference plane parallel to the optical axis, 1
b: Optical axis vertical direction reference plane, 2: Mold, 2a: Optical axis parallel direction reference plane, 2b: Optical axis vertical direction reference plane, 3: Mold, 4: Lens barrel, 4a: Optical axis parallel Direction support parts, 4b: Optical axis vertical direction support parts, 5: Lens, 5a:
Optical axis parallel direction positioning reference surface, 5b: Optical axis vertical direction positioning reference surface, 6: Mold, 6a: Optical axis parallel direction positioning reference surface, 7: Mold, 8: Fitting member, 8a: Optical axis parallel direction Positioning reference plane, 8b: Optical axis vertical direction reference plane,
9: lens barrel, 9a: optical axis parallel direction support portion, 9b: optical axis vertical direction support portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiya Tomisaka 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka, Osaka International Building Minolta Co., Ltd. (72) Inventor Akihiro Mori Azuchi, Chuo-ku, Osaka-shi, Osaka 2-13-3 Machi, Osaka International Building Minolta Co., Ltd. (72) Inventor Shinnori Kawai 2-3-13 Azuchi-cho, Chuo-ku, Osaka City, Osaka Prefecture Minamita International Building (72) Inventor Manami Saka 2-13-3 Azuchi-cho, Chuo-ku, Osaka-shi, Osaka Prefecture Osaka International Building Minolta Co., Ltd. (72) Inventor Naoko Oka 2-3-3 Azuchi-cho, Chuo-ku, Osaka City, Osaka Prefecture Osaka International Building Minolta Co., Ltd.

Claims (2)

[Claims] 1. A glass press lens mold having, on the outer circumference of an effective diameter, a mold for a glass press lens having two surfaces, a positioning reference surface parallel to the optical axis and a positioning reference surface perpendicular to the optical axis. Press lens manufacturing method. 2. A mold for a glass press lens, which has, on the outer circumference of the effective diameter, a positioning reference surface parallel to the optical axis and a positioning reference surface perpendicular to the optical axis.