JP2003104738A - Mold for forming optical element with lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for forming an optical element with a lens barrel which prevents the optical element integrally formed in the lens barrel from deviation of location or light axis. SOLUTION: This mold for forming an optical element is equipped with a forming mold constituted with a cylindrical body mold (1), an upper mold (2) and a lower mold (3) both slidable inside the body mold; a lens barrel (10) is set inside the forming mold and an optical material (20) is disposed inside the lens barrel. The optical material (20) is sandwiched between the upper mold (2) with a transfer face (2A) and the lower mold (3) with a transfer face (3A) to be press heated to form the optical element integrally with the lens barrel. A reference face (31) is provided on the upper face of the lower mold (3) to mount the lens barrel (10), the center part of the upper face of the lower mold (3) is protruded in the axial direction to form a columnar fitting part (32) provided with an outer peripheral face perpendicular to the reference face (31) and the transfer face (3A), where the outer diameter of the fitting part (32) is designed conforming to the inner diameter of the lens barrel (10), and a groove (33) circling along the whole outer peripheral face is formed at the lower end on the outer peripheral face of the fitting part (32) intersecting with the reference face (31).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical element (or glass material) arranged in a lens barrel set in a molding die, and heated and pressed by an upper die and a lower die to provide an optical element in the lens barrel. (Or a glass molded product) A molding die for molding an optical element with a lens barrel integrally molded.

[0002]

2. Description of the Related Art In recent years, optical materials (or glass materials)
When the optical element (or glass molded product) is molded by heating and softening the glass in a heating furnace and then pressurizing it with an upper mold and a lower mold, a lens barrel is provided in a molding mold including a barrel mold, an upper mold, and a lower mold. The optical material (or glass material) is placed in the lens barrel, and the optical material (or glass material) is sandwiched between the upper mold and the lower mold to heat and press the optical material (or glass material). (Material) is made to flow in the outer peripheral direction, the outer peripheral edge thereof is closely bonded to the inner peripheral surface of the lens barrel, and the optical element is integrally molded in the lens barrel. It was (JP-A-6
0-129220 publication)

[0003]

In the above-described method of manufacturing an optical element with a lens barrel, the optical element is integrally molded with the lens barrel set in the molding die. In order to prevent optical axis deviation and positional deviation of the optical element, it is important to hold the lens barrel set in the mold stably. In the molding die in which the optical material (or glass material) placed on the transfer surface of the lower mold is sandwiched between the lower mold and the upper mold and heated and pressed to integrally mold in the lens barrel, it is molded in the lens barrel. The optical axis of the optical element is determined by the positional relationship between the center axis of the lower mold and the lens barrel. Therefore, in the lens barrel to be set in the molding die, the outer peripheral surface of the lower die formed parallel to the central axis of the lower die and the inner peripheral surface of the lens barrel are closely contacted, and the lower end surface of the lens barrel is attached to the center of the lower die. It is desired that the surface be in close contact with the surface perpendicular to the axis. However, the portion where the outer peripheral surface of the lower die intersects the vertical surface cannot be formed vertically due to processing problems. Therefore, the inner peripheral surface and the lower end surface of the lens barrel cannot be brought into close contact with the outer peripheral surface and the vertical surface, resulting in a problem that stable holding cannot be performed.

Therefore, according to the present invention, in manufacturing an optical element with a lens barrel, an optical element with a lens barrel that stably holds the lens barrel and prevents optical axis deviation and positional deviation of an optical element formed in the lens barrel is provided. The object is to provide a molding die for.

[0005]

In order to achieve the above-mentioned object, the present invention provides a mirror in a molding die having a cylindrical barrel die and an upper die and a lower die which slide in the barrel die. With the tube set, the optical material is placed in this lens tube, the optical material is sandwiched between the upper mold and the lower mold having the transfer surface, and the optical element is integrally molded in the lens barrel by heating and pressing. In the mold of the optical element with a lens barrel, a reference surface for mounting the lens barrel is provided on the upper surface of the lower mold, and the central portion of the upper surface of the lower mold is projected in the axial direction, and is perpendicular to the reference surface. A cylindrical fitting part having a transparent outer peripheral surface and a transfer surface at the center of the upper surface is formed, and the fitting part is designed so that the outer diameter of this fitting part matches the inner diameter of the lens barrel, and the fitting is such that the reference surface intersects. A groove is formed on the outer peripheral surface of the lower end of the joining portion so as to make one round along the outer peripheral surface of the fitting portion.

A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a mold for an optical element with a lens barrel in an embodiment of the present invention.
Molding for molding an optical element with a lens barrel in which an optical element is closely adhered to the inner peripheral surface on the upper tip side of the lens barrel 10 set in a molding die including the upper mold 2 and the lower mold 3. Indicates the type.
This molding die includes a tubular body die 1, a cylindrical upper die 2 and a lower die 3, and an upper die 2 and a lower die 3 that slide in the tubular body die 1.
With the optical material (or glass material) 20 disposed inside the lens barrel 10 is sandwiched, heated, and pressed to transfer the transfer surfaces 2A, 3A to the optical material 20 to form an optical function surface. The optical material 20 is caused to flow in the outer peripheral direction so that the outer peripheral edge thereof is closely bonded to the inner peripheral surface of the lens barrel 10 to manufacture an optical element with a lens barrel in which an optical element is integrally molded. It should be noted that, as a forming die, a body die 1, an upper die 2 and a lower die 3 made of a super hard material such as tungsten carbide are used.

The molding die of the present invention comprises a lower die 3 having a transfer surface 3A, a reference surface 31 on which the lens barrel 10 is mounted, and a fitting portion 32 fitted to the inner circumference of the lens barrel 10. Use this lower mold 3
The lens barrel 10 is held on the outer periphery of the fitting portion 32 of the above by holding the lens barrel 10 and the lens barrel 10 is placed on the reference surface 31, thereby shifting the lens barrel 10 with respect to the transfer surface 3A. It is something to hold without doing.

The lower die 3 made of a cemented carbide material such as tungsten carbide is ground using a working tool.
FIG. 2 shows a cross-sectional view of the lower die 3 that has been ground. The reference surface 31 on which the lens barrel 10 is mounted is formed on the upper surface of the lower die 3, and the central portion of the upper surface of the lower die 3 is A cylindrical fitting portion 32 is formed which has an outer peripheral surface that projects in the axial direction and is perpendicular to the reference surface 31, and a transfer surface 3A at the center of the upper surface.

The lower mold 3 of the molding die according to the present invention is a lower mold 3.
Fitting portion 3 formed by axially projecting the central portion of the upper surface of the
The lens barrel 10 is held by fitting the lens barrel 10 to the outer circumference of the reference mold 2, and the reference surface 3 formed on the outer circumference of the fitting portion on the upper surface of the lower mold 3.
1 to mount the lens barrel 10 on the reference surface 31, and by mounting the lens barrel 10 on the reference surface 31, the transfer surface 3A formed in the central portion of the upper surface of the fitting portion 32 forms an optical path inside the lens barrel. It is formed so as to be arranged at the element formation position. That is, the reference plane 31
By mounting the lens barrel 10 on the lens barrel, positional deviation of the optical element formed in the lens barrel is prevented.

The lens barrel 1 fitted on the outer periphery of the fitting portion 32
A cylindrical fitting portion 32 having an outer peripheral surface perpendicular to the reference surface 31 on which the lens barrel 10 is mounted is formed so that 0 can be stably mounted on the reference surface 31. Joint part 3
In order to prevent the displacement of the lens barrel 10 held on the outer periphery of the lens barrel 2, the outer diameter of the fitting portion 32 is designed according to the inner diameter of the lens barrel 10, and the optical axis shift of the optical element formed in the lens barrel is designed. Prevent.

However, as shown in FIG. 2, when the lower die 3 having the fitting portion 32 protruding in the vertical direction with respect to the reference surface 31 is ground using a working tool, the reference surface 31
A gently sloping shoulder R is formed at the intersection of the outer peripheral surface of the fitting portion 32 formed by projecting perpendicularly with respect to the reference surface 31, and no right-angled portion is formed. This is because the tip of the working tool cannot be sharpened in order to have a certain degree of strength, and therefore the tip of the working tool is formed in a rounded shape.

For example, in the embodiment shown in FIG. 2, the outer diameter φ3.
The lens barrel 10 having an outer diameter of 3.75 mm is fitted to the fitting portion 32 of 3 mm.
The wall thickness of the thin-walled portion of the lens barrel fitted with
A small-sized optical element with a lens barrel having a size of not more than mm is manufactured, and a shoulder portion R formed at a position where the outer peripheral surface of the fitting portion 32 and the reference surface 31 intersect each other causes )
Does not contact the reference surface 31 and is about 0.2 mm from the reference surface 31
The lens barrel 10 is set so as to shift upward. That is, the axial displacement of the optical element formed in the lens barrel (about 0.2 m
m) occurs. Even with such a small positional deviation, a small optical element with a lens barrel deteriorates the optical function and causes a trouble. Further, in this embodiment, the shoulder R makes the installation state of the lens barrel 10 with respect to the reference surface 31 unstable, and the optical axis of the optical element formed in the lens barrel may tilt.

That is, the outer diameter of the fitting portion 32 is designed according to the inner diameter of the lens barrel 10 (the outer diameter of the fitting portion 32 is designed to be equal to the inner diameter of the lens barrel 10), and the fitting portion 32 Lens barrel 1 on the outer circumference
By fitting 0, the horizontal displacement of the lens barrel held by the fitting portion 32 is prevented, and the optical axis displacement of the optical element integrally molded in the lens barrel is prevented. If a gently sloping shoulder R is formed at the intersection of the outer peripheral surface of the fitting portion 32 and the reference surface 31,
Due to the shoulder R, the lower end of the lens barrel 10 does not come into contact with the reference surface 31 and an axial displacement of the optical element integrally formed in the lens barrel occurs.

On the other hand, if the lens barrel 10 is to be installed on the reference surface 31 while avoiding the shoulder R, the inner diameter of the lens barrel 10 must be designed to be larger than the outer diameter of the fitting portion 32. The fitting portion 32 and the inner peripheral surface of the lens barrel 10 do not come into close contact with each other, which causes a positional deviation in the horizontal direction. When a smaller optical element with a lens barrel is formed, the length from the side of the reference surface 31 that intersects with the fitting portion 32 to the end of the reference surface on the opposite side, that is, the reference surface on which the lens barrel 10 is mounted. Since the width of 31 cannot be increased, if the shoulder R is to be avoided, the lens barrel 10 may not fall on the reference surface 31 and may fall off.

Further, in manufacturing a small-sized optical element with a lens barrel, the wall thickness of the lens barrel 10 is thin, so that the lens barrel 10 is placed in a molding die.
When the optical material 20 placed in the lens barrel is set and heated while being sandwiched between the upper mold 2 and the lower mold 3 and heated and pressed, a shoulder portion R formed on the outer peripheral surface of the lower end of the fitting portion 32. There is a possibility that the lens barrel 10 may be deformed along the shape of the above.

Further, when manufacturing a small optical element with a lens barrel having the lens barrel 10 having a thin wall thickness, the lens barrel 1 having a thin wall thickness is used.
0 If the lower end (opposite surface) is chamfered according to the shape of the shoulder R, the lower end of the lens barrel 10 has no flat portion and is sharpened, and the manufactured lens-equipped optical element has a sharply shaped lower end of the lens barrel. However, it cannot be held in a stable state and accurate positioning becomes impossible.

Therefore, the lower mold 3 of the mold according to the present invention is used.
On the outer peripheral surface of the lower end of the fitting portion 32 where the reference surface 31 intersects,
A groove 33 is formed around the outer peripheral surface of the fitting portion 32,
The shoulder R formed at the intersection of the reference surface 31 and the outer peripheral surface of the fitting portion 32 is removed, and the lower end of the lens barrel 10 fitted and held on the outer periphery of the fitting portion 32 is attached to the fitting portion 32. Is grounded to a reference surface 31 formed perpendicular to the outer peripheral surface of.

FIG. 3 is a sectional view of the lower die 3 of the molding die according to the present invention, in which the shoulder portion R of the lower die 3 shown in FIG.
In order to remove the above, the groove 33 that makes one round along the outer peripheral surface of the fitting portion 32 is ground on the outer peripheral surface of the lower end of the fitting portion 32. That is, after molding the lower mold 3 including the transfer surface 3A, the reference surface 31, and the fitting portion 32 with a mold, the reference surface 31
A groove 33 that makes a round along the outer peripheral surface of the fitting portion 32 on the outer peripheral surface of the lower end of the fitting portion 32 that protrudes in a direction perpendicular to the
Is ground toward the center axis of the lower mold 3.

The groove 33 which goes around the lower end outer peripheral surface of the fitting portion 32 toward the central axis of the lower mold 3 along the outer peripheral surface of the fitting portion 32 has an angle of incidence (lower surface) along the reference surface 31. The grinding blade may be brought into contact with the outer peripheral surface of the lower end of the fitting portion 32 at an incident angle that intersects at right angles to the central axis of the mold 3 to grind, but the incident angle may be slightly inclined with respect to the reference surface 31. It is preferable that the grinding blade is brought into contact with the outer peripheral surface of the lower end of the fitting portion 32 at (incident angle intersecting with the center axis of the lower die 3) to grind toward the center axis of the lower die 3.

As shown in FIG. 3, on the outer peripheral surface of the lower end of the fitting portion 32 where the reference surface 31 intersects, a groove 33 is formed around the outer peripheral surface of the fitting portion 32, and the shoulder portion R is removed. By removing it, the lens barrel 10 can be fitted to the outer periphery of the fitting portion 32 in which the upper surface of the lower mold 3 is projected in the axial direction, and the lower end of the lens barrel 10 can be reliably grounded to the reference surface 31. It is possible to manufacture an optical element with a lens barrel in which the optical axis deviation and the positional deviation of the optical element integrally molded with the lens are prevented.

That is, according to the present invention, the lower surface having the transfer surface is provided with the reference surface and the fitting portion, the lens barrel is fitted to the outer periphery of the fitting portion, and the lens barrel is placed on the reference surface. , In a molding die that holds the lens barrel with a lower mold and prevents positional deviation and optical axis displacement of the optical element formed in the lens barrel, transfer to the outer peripheral surface perpendicular to the reference surface and the central portion of the upper surface. By designing the outer diameter of the cylindrical fitting part with the surface to match the inner diameter of the lens barrel, the lens barrel fitted to the outer periphery of the fitting part is securely held and formed inside the lens barrel. The optical axis shift of the optical element to be prevented is prevented, the lower end outer peripheral surface of the fitting portion where the reference planes intersect is ground toward the central axis, and a groove is formed along the outer peripheral surface of the fitting portion. , The shoulder R formed at the intersection of the reference surface and the outer peripheral surface of the fitting portion is removed, and the lens barrel is attached to the reference surface. End securely to the ground and to prevent misalignment of the optical elements formed in the lens barrel. Therefore, by using the molding die according to the invention, it is possible to prevent the positional deviation of the optical element formed in the lens barrel caused by the shoulder portion R and to provide a highly accurate small optical element with a lens barrel. .

[Brief description of drawings]

FIG. 1 is a sectional view of a molding die according to the present invention.

FIG. 2 is a cross-sectional view of a lower mold formed by a mold.

FIG. 3 is a cross-sectional view of a lower mold of a molding die according to the present invention.

[Explanation of symbols]

1 body type 2 Upper mold 2A Transfer surface 3 Lower mold 3A Transfer surface 31 Reference plane 32 Fitting part 10 lens barrel 20 Optical material (or glass material)

Claims (3)

[Claims] 1. A lens barrel (10) is set in a molding die having a tubular barrel die (1) and an upper die (2) and a lower die (3) which slide in the barrel die. At the same time, an optical material (20) is placed in this lens barrel, and an upper mold (2) having a transfer surface (2A).
And the lower mold (3) having the transfer surface (3A), the optical material (2
0) is sandwiched, heated and pressurized to integrally mold the optical element in the lens barrel, and in the mold for the optical element with the lens barrel, the lens barrel (10) is placed on the upper surface of the lower mold (3). Reference plane (3
1) is provided, and the central portion of the upper surface of the lower mold (3) is projected in the axial direction,
A cylindrical fitting portion (3) having an outer peripheral surface perpendicular to the reference surface (31) and a transfer surface (3A) at the center of the upper surface.
2) is formed, the outer diameter of the fitting portion (32) is designed according to the inner diameter of the lens barrel (10), and the outer peripheral surface of the lower end of the fitting portion (32) where the reference plane (31) intersects is formed. A mold for an optical element with a lens barrel, wherein a groove (33) is formed along the outer peripheral surface of the fitting portion (32). 2. A transfer surface (3A) and a reference surface (31),
After forming the lower mold (3) having the fitting part (32),
The fitting portion (3 that protrudes perpendicularly to the reference surface (31)
The groove (33), which makes one round along the outer peripheral surface of the fitting portion (32), is formed on the outer peripheral surface of the lower end of 2) by grinding toward the central axis of the lower mold (3). A mold for an optical element with a lens barrel according to claim 1. 3. The molding die for an optical element with a lens barrel according to claim 1, wherein a small optical element with a lens barrel is manufactured.