JP4727487B2 - Manufacturing method of optical component and mold for molding - Google Patents

Description

  The present invention relates to a method for manufacturing an optical component obtained by integrally joining an optical element material and a frame member arranged in a molding die, and a molding die for the same.

  In recent years, a technique for molding an optical element such as a lens used in an optical apparatus by a molding means has been frequently used. On the other hand, with the reduction in thickness of optical devices, for example, the lens itself as an optical element is required to be thin. However, in consideration of centering work for removing the peripheral edge of the lens for centering and mounting on a lens frame, it is often the case that the lens thickness cannot be reduced so much.

On the other hand, for example, in Patent Document 1, a cylindrical opening portion and a locking portion facing inward from the opening portion are integrally formed in a metal frame, and a lens material is disposed in the opening portion so as to form an inner surface of the opening portion. There is a technology in which a lens material is placed on the stepped part with the inner surface of the locking part, this lens material is heated and pressure-molded, and the lens and the metal frame are integrally molded at the stepped part in the opening of the metal frame. It is disclosed.
Japanese Patent No. 2878372 (second page, FIG. 1)

  However, in Patent Document 1, a shape error called astigmatism occurs in a lens integrally formed with a metal frame. The term “ass” refers to a state in which the radius of curvature differs between a cross section with a lens and a cross section perpendicular to the cross section.

  In addition, as long as estimated from the drawings of Patent Document 1, when the ratio of the lens peripheral thickness (edge thickness) to the lens center thickness, the ratio of the lens peripheral thickness to the frame thickness, and the like are considered, the above-described stress is a problem. Even if it exists, the problem of ass does not occur. This is because these problems become more apparent as the metal frame and lens material are made thinner.

  On the other hand, ideally, in order to suppress the occurrence of asymmetry, it is necessary to match the centers of the mold, the metal frame, and the lens material. For this purpose, it is desirable to mold the metal frame in a state of being fixed so as to be substantially coaxial with the center of the mold.

  For example, as shown in FIGS. 9A and 9B, a disk-shaped frame member 16 with a hole placed on the lower mold 12 is moved by the frame regulating member 15 in the optical axis direction and in a direction substantially orthogonal thereto. If the restriction is made so that it cannot be performed, it seems that the center of the upper mold 11, the lower mold 12, the optical element material 14, and the metal frame member 16 coincide with each other and ideal molding becomes possible.

  However, in actuality, the upper and lower molds themselves have a slight eccentricity, and there is a relative eccentricity between the upper and lower molds. In addition, there is a temperature distribution in the upper mold 11, the lower mold 12, and the optical element material 14, and a situation occurs in which the upper mold 11, the lower mold 12, and the optical element material 14 are not necessarily formed coaxially with the center of the frame member 16.

  In such a state, the stress applied to the frame member 16 is not uniform, which leads to asymmetry of the optical element, that is, asphalt. For this reason, for example, when the upper mold 11 is moved closer to the lower mold 12 in a state where the upper mold 11 is inclined with respect to the optical axis, the optical element material 14 has a portion that is easier to expand than the other portions.

  As a result, as shown by the arrow in FIG. 9A, a cross section in which no stress is applied to the inner periphery of the disk-shaped frame member 16 with a hole and a cross section in which the stress is applied are generated. And since the curvature radius differs in the cross section to which stress is added, and the cross section which is not added, asphalt will arise.

  The present invention has been made to solve such a problem. The object of the present invention is to follow the inner periphery of the frame member according to the spread of the optical element material, and to mold at the most balanced position. An object of the present invention is to provide a method of manufacturing an optical component and a mold for molding the same.

In order to achieve the above object, the present invention provides an optical element material sandwiched between a pair of opposing molds and a frame member disposed in the vicinity of the optical element material. In the mold for molding optical components that are pressed and joined together after softening,
The frame member, when the pressing is movable in a direction substantially perpendicular to the pressing direction,
Frame regulating member for regulating the movement of the frame member is provided, characterized in that.

In the above mold for molding an optical component, the frame member is movable in the pressing direction during the pressing,
The frame regulating member, it is possible to have a regulating portion for regulating the movement of the pressing direction of the frame member.

In the above mold for molding an optical component, the frame member is movable in the pressing direction during the pressing,
It said pair mold said frame member and the mold opposite sides of the can, it is possible to have a regulating portion for regulating the movement of the pressing direction of the frame member.

The present invention also provides a frame member disposed in the vicinity of the optical element material when the optical element material sandwiched between a pair of opposing molds is pressed by heat softening and molded. In the manufacturing method of the optical component that is integrally bonded to the element material,
The frame member, when the pressing is movable in a direction substantially perpendicular to the pressing direction,
The movement of the frame member is restricted by a frame restriction member .

  According to the present invention, since the inner periphery of the frame member can be traced according to the spread of the optical element material and molding can be performed at the position with the best balance, it is possible to obtain a thin optical element free of asphalt.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing a first embodiment of an optical component molding die. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of the prior art example mentioned above, or is equivalent.

  In FIG. 1, a molding die 10 includes an upper die 11, a lower die 12, and a cylindrical sleeve 13. The upper mold 11 and the lower mold 12 are inserted from both ends of the sleeve 13 so that the convex molding surface 11 a and the concave molding surface 12 a face each other inside the sleeve 13. It is slidable in the axial direction. Also, a molding material (optical element material) 14 made of a thermoplastic material such as glass, acrylic, polycarbonate, or the like is disposed between the molding surface 11a of the upper mold 11 and the molding surface 12a of the lower mold 12.

  In the present embodiment, the upper mold 11 and the lower mold 12 are manufactured by polishing a cemented carbide such as tungsten carbide (WC). The molding material 14 has, for example, a ball shape (spherical shape). Here, for convenience of explanation, a ball-shaped molding material and a lens obtained by molding the molding material are denoted by the same reference numeral 14 throughout.

  In the present embodiment, the lower mold 12 has a small-diameter columnar portion (substantially cylindrical shape) 112a and a large-diameter columnar portion (substantially cylindrical shape) 112b, and a step 112c is formed at the boundary between them. ing. And the cylindrical frame control member 15 is inserted by this small diameter columnar part 112a. The frame restricting member 15 has an outer diameter smaller than the inner diameter of the sleeve 13, and its bottom surface is in contact with and supported by the stepped portion 112c.

  Further, a counterbore 115 that is shallowly formed is formed at the upper end of the frame restricting member 15. A wall surface 115a around the counterbore 115 restricts movement of a frame member 16 (described later) in a direction substantially perpendicular to the pressing direction of the upper mold 11 (radial direction). Note that the seating surface of the counterbore hole 115 is formed at substantially the same height as the outer peripheral end portion of the molding surface 12 a of the lower mold 12.

  Further, a disc-shaped frame member 16 with a hole having a smaller diameter than the counterbore hole 115 is placed on the seating surface of the counterbore hole 115. The frame member 16 is made of, for example, metal, and in the present embodiment, a stainless steel member is used.

  When the mold is set, a ball-shaped molding material 14 is placed on the molding surface 12a of the lower mold 12, and a disc-shaped frame with a hole is formed on the seating surface of the counterbore 115 so that the molding material 14 is located at the center. The member 16 is placed.

  At the time of molding, the ball-shaped molding material 14 is heated and softened to a predetermined temperature in the state of the mold set of FIG. 1 described above, and the upper mold 11 slides in the sleeve 13 toward the lower mold 12. Then, the ball-shaped molding material 14 is pressed and crushed, and the molding surface 11 a of the upper mold 11 and the molding surface 12 a of the lower mold 12 are transferred to the molding material 14.

  In this case, as shown in FIG. 2, when the central axis O ′ of the upper mold 11 is inclined with respect to the central axis O of the lower mold 12, in the drawing, the molding material 14 increases in the right side portion, The expanded part pushes the inner peripheral surface of the frame member 16 rightward (in the radial direction). Accordingly, the frame member 16 moves on the seating surface of the counterbore hole 115 to the right in the drawing.

  Then, as shown in FIG. 3, when the press molding is finished by sliding the upper mold 11, the center of the outer diameter of the lens 14 and the center of the frame member 16 substantially coincide with each other and are added to the inner peripheral surface of the frame member 16. Variation in stress can be kept small. At this time, the right portion of the frame member 16 is slightly lifted from the seating surface, which has the advantage that stress applied to the inner peripheral surface of the frame member 16 is relieved.

  In FIG. 3, when the right part of the frame member 16 is lifted, the outer peripheral portion of the molding surface 11a of the upper mold 11 restricts the frame member 16 from being lifted by a predetermined amount or more. That is, the outer peripheral portion of the molding surface 11a of the upper mold 11 forms a restricting portion that restricts the movement of the frame member 16 in the pressing direction (optical axis direction) of the upper mold 11.

FIGS. 4A and 4B show the dimensional relationship between the frame regulating member 15 and the frame member 16.
That is, if the diameter of the outer periphery of the disk-shaped frame member 16 with holes is A and the diameter of the counterbore hole 115 formed in the frame regulating member 15 is B,
B> A
Have the relationship.

  Thereby, the frame member 16 placed in the counterbore hole 115 can move within a limited range on the seating surface of the counterbore hole 115. At this time, it is sufficient to place the frame member 16 in the vicinity of the substantially center of the counterbore 115 with general care.

  In the present embodiment, the case where the cylindrical frame restricting member 15 is inserted into the lower mold 12 has been described. However, the present invention is not limited to this. For example, the lower mold 12 and the frame restricting member 15 are integrally fixed. Also good.

According to the present embodiment, the frame member 16 that restricts the movement of the frame member 16 in the direction (radial direction) substantially orthogonal to the pressing direction of the upper die 11 is provided, for example, conventionally. The asperity of the optical element was 0.4λ to 1.0λ, but could be reduced to 0.05λ to 0.3λ (λ is the wavelength of light). In this way, a thin optical element free of asphalt can be obtained.
(Second Embodiment)
FIG. 6 is a diagram showing a second embodiment of a molding die for optical components. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

  Before explaining the present embodiment, for example, as shown in FIG. 5, in the case of a lens having a deep spherical hole, when the frame member 16 is inclined, a difference occurs in the generation of stress depending on the cross section, and asphalt is generated. The arrows in FIG. 5 indicate how the frame member 16 is tightened during cooling. This is likely to occur when the linear expansion coefficient of the frame member 16 is larger than the lens material.

  Therefore, in the present embodiment, the frame member 16 is provided with a frame restricting member 15 that prevents it from being generated by raising and tilting one end in the radial direction of the frame member 16 more than necessary, thereby suppressing the inclination. is there.

  In FIG. 6, the molding die 10 is different from the first embodiment in that a cylindrical collar member 17 is fitted into the small-diameter columnar portion 112 a of the lower die 12, and the outer circumference of the collar member 17 is further increased. This is the point where the frame restricting member 15 is inserted into the side.

  In the present embodiment, the frame member 16 is placed on the upper end surface of the collar member 17, and the outer diameter of the collar member 17 is slightly larger than the outer diameter of the frame member 16. This is because the frame member 16 can be moved in a direction substantially orthogonal to the pressing direction of the upper mold 11 within the range of the difference in outer diameter between the collar member 17 and the frame member 16.

  The frame restricting member 15 is formed with an inner peripheral surface 15a into which the collar member 17 is inserted, and an upper end portion of the inner peripheral surface 15a is formed with a restricting portion 15b so as to protrude toward the center side. The frame restricting member 15 is fixed to the lower die 12 by bolts 18 with the bottom surface thereof being in contact with and supported by the step 112c of the lower die 12. The bolt 18 is removed every time the molding process is performed, and the frame restricting member 15 is detachable.

  In the present embodiment, the case where the frame restricting member 15 is detachably fixed to the lower mold 12 with the bolts 18 has been described. However, the present invention is not limited to this, and the detachable attachment to the lower mold 12 is possible by other fixing means such as a key. It is good even if it is free.

  The frame restricting member 15 of the present embodiment restricts the movement of the frame member 16 in a direction substantially orthogonal to the pressing direction of the upper mold 11 by the inner peripheral surface 15a, and the frame member 16 by the restricting portion 15b. The movement in the pressing direction (optical axis direction) of the mold 11 is restricted.

In this case, as shown in FIG. 7, assuming that the entire gap between the upper end surface of the collar member 17 and the restricting portion 15b of the frame restricting member 15 is H and the plate thickness of the frame member 16 is t,
H = t + c (clearance)
Have the relationship.

  This clearance c is a value for enabling the frame member 16 to move in a direction substantially orthogonal to the pressing direction of the upper mold 11, and theoretically it may be about 1 μ, but in consideration of surface roughness etc. It is preferable that the thickness is about 10 μm.

In addition, for example, when a tolerance of 5 ′ or less is set for the product function, the inclination θ of the frame member 16 with respect to the optical axis of the lens obtained by molding is set as follows:
If the outer diameter of the frame member 16 is A, the plate thickness of the frame member 16 is t, and the clearance is c,
θ ≧ tan ⁻¹ c / A
It is necessary to satisfy the relationship.

According to the present embodiment, since the frame restricting member 15 that restricts the frame member 16 from moving in the pressing direction of the upper mold 11 and the direction substantially orthogonal thereto is provided, for example, conventionally, an optical element to be molded As a result, the asphalt of 0.4λ to 1.0λ could be reduced to 0.05λ to 0.2λ (λ is the wavelength of light).
(Third embodiment)
FIG. 8 is a diagram showing a third embodiment of a molding die for optical components. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

  As shown in FIG. 8, in the present embodiment, a frame restricting member 15 is provided on the lower die 12, and a frame restricting member 15 ′ is also attached to the upper die 11 with bolts 18 so as to face the frame restricting member 15. It is attached detachably. Further, similarly to the first embodiment, a counterbore 115 that is shallowly formed is formed in the upper end portion of the frame restricting member 15.

  In the present embodiment, the frame restricting member 15 ′ is detachably attached to the upper mold 11 with the bolts 18. However, the present invention is not limited to this, and may be fixed integrally to the upper mold 11, for example. The frame member 16 is restricted from moving in the pressing direction (optical axis direction) of the upper die 11 by the restriction portion 15 a ′ of the frame restriction member 15 ′ attached to the upper die 11.

  That is, in the present embodiment, the lower frame restricting member 15 restricts the movement of the frame member 16 in a direction substantially orthogonal to the pressing direction of the upper mold 11, and the upper frame restricting member 15 ′ The movement of 16 in the pressing direction (optical axis direction) of the upper mold 11 is restricted.

  According to the present embodiment, by providing the frame regulating member 15 that regulates the movement of the frame member 16 in the pressing direction (optical axis direction) of the upper mold 11 and the direction (radial direction) substantially orthogonal thereto. The ass of the optical element to be molded can be reduced.

It is a figure which shows 1st Embodiment of the shaping | molding die for optical components which concerns on this invention. It is a principal part enlarged view same as the above. It is a principal part enlarged view same as the above. (A) is the principal part enlarged plan view same as the above, (b) is the front view. It is a principal part enlarged view same as the above. It is a figure which shows 2nd Embodiment of the shaping | molding die for optical components. It is a principal part enlarged front view same as the above. It is a figure which shows 3rd Embodiment of the shaping | molding die for optical components. (A) is a top view of the shaping | molding die for the conventional optical components, (b) is the front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mold 11 Upper mold 11a Molding surface 12 Lower mold 12a Molding surface 112a Small diameter columnar part 112b Large diameter columnar part 112c Step part 13 Sleeve 14 Molding material 15 Frame regulating member 15a Inner peripheral surface 15b Restricting part 15 'Frame regulation Member 15a 'Restricting part 115 Counterbore 115a Wall surface 16 Frame member 17 Collar member 18 Bolt

Claims (4)

An optical element in which an optical element material sandwiched between a pair of opposing molds and a frame member disposed in the vicinity of the optical element material are pressed together after being softened by heating, and are integrally joined. In molds for parts,
The frame member, when the pressing is movable in a direction substantially perpendicular to the pressing direction,
A frame restricting member for restricting the movement of the frame member is provided ;
A mold for molding optical parts characterized by the above. The frame member is movable in the pressing direction during the pressing,
The frame restricting member has a restricting portion that restricts movement of the frame member in the pressing direction .
The mold for molding an optical component according to claim 1. The frame member is movable in the pressing direction during the pressing,
The mold on the side facing the frame member of the pair of molds has a restricting portion that restricts movement of the frame member in the pressing direction .
The mold for molding an optical component according to claim 1. When an optical element material sandwiched between a pair of opposing molds is pressed after being softened by heating, a frame member disposed in the vicinity of the optical element material is integrated with the optical element material. In the manufacturing method of optical components to be joined,
The frame member, when the pressing is movable in a direction substantially perpendicular to the pressing direction,
The movement of the frame member is regulated by a frame regulating member ;
An optical component manufacturing method characterized by the above.

Images