JP3430208B2 - Injection mold for plastic optical lens and method of manufacturing plastic optical lens - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to plastic optics.
Injection mold for lens and plastic optical lens
Manufacturing method.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of a conventionally proposed injection molding die of this kind. The injection molding die 100 includes a stationary-side die 101 and a moving-side die 102, which are joined together at a joining surface 103 so as to be separable from each other.

The fixed-side die 101 includes a fixed-side plate 10
4 and a mounting plate 105 for mounting it. To the fixed side plate 104, via the fixed side sleeve 106,
A fixed lens insert 107 having a lens molding surface is fitted and fixed to the fixed plate mounting plate 105 with a bolt 108. A taper bush 109 is fixed to the fixed-side plate mounting plate 105 at a position apart from the fixed-side sleeve 106. A spool 110, a runner 111, and a cavity 112 are provided at the center of the fixed side plate 104.
A gate 113 that communicates with is provided.

The moving side mold 102 includes a moving side plate 11
4 and a mounting plate 115 for mounting it. On the moving side plate 114, via the moving side sleeve 116,
The moving side lens insert 117 having a lens molding surface is fitted. The receiving plate 118 of the moving side plate 114 and the mounting plate 1
A spacer block 119 is interposed between the spacers 15, and protruding plates 120 and 121 are installed inside the spacer block 119. The rear end 122a of the protruding rod 122 is held by the protruding plates 120 and 121, and the protruding rod 1
The front end 122b of 22 is connected to the moving side lens insert 117 by screwing.

The protruding plates 120 and 121 hold the rear end 123a of the ejector pin 123, and the front end 123b of the ejector pin 123 extends close to the runner 111.

A taper guide 124 is provided on the movable side plate 114, and the taper bush 109
It has been attempted to suppress the misalignment between the fixed side lens insert 107 and the moving side lens insert 117 by fitting them to each other.

[0007]

However, this injection molding die 100 has a taper bush 109 and a taper guide 1 for suppressing misalignment of the lens inserts 107 and 117.
24 is located away from the lens inserts 107 and 117, and a plurality of members are interposed between the lens inserts 107 and 117 to indirectly perform centering.

In order to mount the fixed side lens insert 107 on the fixed side plate 104, between the fixed side plate 104 and the fixed side sleeve 106, and the fixed side sleeve 10.
There is a slight clearance between the fixed lens insert 107 and the fixed lens insert 107, and since the fixed lens insert 107 is fixed to the mounting plate 105 with the bolt 108, the fixed lens insert 107 is biased.

This also applies to the moving side lens insert 117, and some clear lands are provided between the moving side plate 114 and the moving side sleeve 116, and between the moving side sleeve 116 and the moving side lens insert 117. Moreover, since the moving side lens insert 117 is projected and screwed by the tip 122b of the rod 122, the moving side lens insert 117 is biased.

From the above, the fixed side lens insert 10
7 and the moving side lens insert 117 cause a misalignment, and in the case of an optical lens, the misalignment appears as a misalignment of the optical axis, resulting in deterioration of molding quality.

An object of the present invention is to solve the problems of the prior art, the structure is simple and highly molding precision plus
Injection mold and plastic for tic optical lens
It is to provide a manufacturing method of an optical lens .

[0012]

In order to achieve the above object, the first means of the present invention has a fixed side mold and a moving side mold, and at least the moving side mold has a moving side lens. A moving-side molding sesame having a molding surface, a moving-side holding member that holds the moving-side molding sesame from the outside, and a moving-side ball retainer that rotatably holds balls on the peripheral wall of the ball holding cylinder at intervals. The moving-side ball retainer is inserted between the moving-side molding sesame and the moving-side holding member, and in either one of the moving-side holding member or the fixed-side mold,
A fitting concave portion having a tapered surface is provided on the peripheral surface, and a fitting convex portion having a tapered surface on the peripheral surface and fitted to the fitting concave portion is provided on the other of the fixed-side mold and the moving-side holding member. It is characterized by that.

According to a second aspect of the present invention, in the first means, the fixed side mold has a fixed side molding sesame having a fixed side lens molding surface, and a fixed side for holding the fixed side molding sesame from the outside. A holding member and a fixed-side ball retainer that rotatably holds balls on the peripheral wall of the ball-holding cylinder at an interval, and insert the fixed-side ball retainer between the fixed-side molding sesame and the fixed-side holding member. It is characterized by.

A third means of the present invention uses the injection molding die for a plastic optical lens of the first means or the second means, and joins the fixed side die and the moving side die with each other. It is characterized by injecting and filling a molten resin into the cavity formed in the above.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an injection molding die according to the first embodiment, and FIG. 2 is an enlarged cross-sectional view near the ball retainer of the injection molding die.

First, the overall structure of the injection molding die will be described with reference to FIG. The moving side lens sesame 2 is arranged inside the moving side outer sesame (moving side nest) 1, and the fixed side lens sesame 4 is arranged inside the fixed side outer sesame (fixed side nest) 3. When the mold is opened and closed, the movable-side outer sesame 1 is brought into contact with and separated from the fixed-side outer sesame 3.

A fitting recess 5 having a tapered peripheral surface around the moving lens sesame 2 is provided on the end surface of the moving outer sesame 1, while a fixed lens sesame 4 is provided on the end surface of the fixed outer sesame 3. As a center, a fitting convex portion 6 having a tapered peripheral surface is provided. The taper angle of the fitting concave portion 5 and the taper angle of the fitting convex portion 6 are the same. As shown in the figure, the fitting convex portion 6 is inserted into the fitting concave portion 5 when the mold is closed, and the fitting convex portion 6 is fitted when the insertion is completed. The peripheral surface of the convex portion 6 is evenly adhered to the peripheral surface of the fitting concave portion 5.

The lens sesame 2 and 4 have lens molding surfaces 2a and 4a each having a predetermined shape at the tips thereof, thereby forming a cavity corresponding to the outer shape of the molded product.

Outer sesame seeds 1 and 3 into which the lens sesame seeds 2 and 4 are inserted
Each of the retainer housings 7 is formed in the center of the ball retainer 7, and the ball retainer 8 is interposed therein. The ball retainers 8 are arranged in five rows in the central axis direction as shown in FIG.
It is composed of a large number of balls 9 arranged in a row and a ball holding cylinder 10 which holds the balls 9 on the peripheral wall at predetermined intervals so as to be rotatable.

The balls 9 are made of, for example, bearing steel (hardness: H
RC58) or stainless steel (SUS440) and the like, and the ball holding cylinder 10 is made of various materials such as stainless steel, brass, and hard synthetic resin. Particularly, those having high rigidity and light weight have a small motion inertial force and a shaft. Excellent in high-speed reciprocal directional movement. The array of balls 9 on the peripheral wall of the ball holding tube 10, (see FIG. 1) staggered five rows in the central axial direction, include three rows of parallel-shaped (see FIG. 2) and a spiral, the central axis It should be arranged in multiple columns in each direction.
Yes.

As shown in FIG. 2, a part of each ball 9 slightly projects from the outer peripheral surface and the inner peripheral surface of the ball holding cylinder 10,
The portion protruding from the outer peripheral surface of the ball holding cylinder 10 is the outer sesame 1
The portion of the ball holding cylinder 10 that rolls on the inner peripheral surface of (3) and projects from the inner peripheral surface of the ball holding cylinder 10 rolls on the outer peripheral surface of the lens sesame 2 (4).

Slightly (for example, several μm) from the gap X between the lens sesame 2 (4) and the outer sesame 1 (3) holding it.
By using the ball 9 having a large diameter, the elasticity of the ball 9 is used (a slight preload state is maintained) to match the central axes Y of the lens sesame 2 (4) and the outer sesame 1 (3). In addition, it is possible to secure a uniform space Z between the frames of the lens sesame 2 (4) and the outer sesame 1 (3).

It is desirable that the hardness of the ball 9 is slightly lower than the hardness of the outer sesame 1 and 3 and the lens sesame 2 and 4 on which the ball 9 rolls. The rotation of the large number of balls 9 allows the lens sesame 2 (4) to move smoothly and stably in the axial direction with respect to the outer sesame 1 (3). Further, in this way, a large number of balls 9 are dispersed in the ball holding cylinder 10 ,
By holding, the fluctuating load and the eccentric load on the outer sesame 1 and 3 and the lens sesame 2 and 4 are small, and the accurate linear movement of the lens sesame 2 (4) is possible.

The center axes Y of the outer sesame 1 and the lens sesame 2 are aligned with each other through the ball retainer 8, the center axes Y of the outer sesame 3 and the lens sesame 4 are aligned with each other, and the fitting recess 5 is centered on the lens sesame 2 Since the fitting convex portion 6 is formed around the lens sesame 4 as a center,
By tapering the stationary side outer sesame 3 and the stationary side sesame 3, the moving side lens sesame 2 and the stationary side lens sesame 4 are inevitably aligned with each other. Then, the optical lens 11 can be molded by injecting a molten transparent resin into the cavity formed by the lens molding surfaces 2a and 4a of the lens sesame 2 and 4 to fill and hold the resin. 24 in FIG.
Is an adjusting sesame for adjusting the axial positions of the lens sesame 2 and 4.

In this embodiment, the fitting concave portion 5 is provided on the moving side outer sesame 1 and the fitting convex portion 6 is provided on the stationary side outer sesame 3. However, on the contrary, the fitting convex portion 6 is provided on the moving side outer sesame 1. , Sesame outside fixed side 3
It is also possible to provide a fitting recess 5 in the.

FIG. 3 is a sectional view of an injection molding die according to the second embodiment of the present invention. 1 in the figure is sesame outside the moving side, 2
Is movably held by the moving side lens sesame on the moving side outer sesame 1 via the ball retainer 8. Reference numeral 3 is a fixed-side outer sesame, and 4 is a fixed-side lens sesame, which is directly press-fitted into the fixed-side outer sesame 3 without a ball retainer and integrated so that there is no clearance.

Reference numeral 12 is a guide bush, which is a fixed side outer sesame 3
The guide bush 12 is integrated so as to have no clearance, and a fitting recess 5 having a tapered surface on the peripheral surface is formed at the lower end opening of the guide bush 12. Reference numeral 13 is a guide pin, which is press-fitted into the moving-side outer sesame 1 so as to be integrated so that there is no clearance. The guide pin 13 has a tapered surface on the peripheral surface and is tightly fitted to the fitting recess 5. Is formed with a fitting convex portion 6 that fits into the.

Reference numeral 14 is a fixed side mounting plate, 15 is a fixed side template,
16 is a moving side template, 17 is a receiving plate, 18 is a spacer block, 19 is a moving side mounting plate, 20 is a protruding rod, 21
Is an ejector pin, 22 is an ejector lock plate, and 23 is an ejector plate.

In this embodiment, the guide bush 12 is press-fitted into the fixed outer sesame 3 and the guide pin 1 is fitted into the movable outer sesame 1.
Although 3 is press-fitted, the fitting side concave portion 5 may be integrally formed on the fixed side outer sesame 3, or the fitting convex portion 6 may be integrally formed on the moving side outer sesame 1.

In this embodiment, the fixed outer sesame 3 is provided with the guide bush 12 (fitting concave portion 5) and the movable outer sesame 1 is provided with the guide pin 13 (fitting convex portion 6). It is also possible to provide the fixed outer sesame 3 with the guide pin 13 (the fitting convex portion 6) and the movable outer sesame 1 with the guide bush 12 (the fitting concave portion 5).

[0031]

[0032]

As described above, the present invention has the above-mentioned structure, and at least the moving-side molding sesame and the moving-side holding member are securely aligned with each other, and the gap between the molding sesame and the holding member is evenly secured. It is possible, and it becomes a smooth and stable movement. Moreover, the fixed-side mold and the moving-side holding member that faces the fixed-side mold are taper-fitted with each other, so that the fixed-side mold and the movable-side mold are accurately centered. In particular, according to the second aspect of the invention, since the ball retainer is provided in both the fixed-side mold and the moving-side mold, the centering of the fixed-side molding sesame and the moving-side molding sesame is more accurate.

Therefore, as compared with the conventional one described with reference to FIG. 4, a plastic optical device having a simple structure and a high molding precision is provided.
Injection mold for lens and plastic optical lens
It is possible to provide a method of manufacturing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an injection molding die according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view in the vicinity of a ball retainer of the injection molding die.

FIG. 3 is a cross-sectional view of an injection molding die according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a conventional injection mold.

[Explanation of symbols]

1 Sesame outside the moving side 2 Moving side lens sesame 2a Moving side lens sesame molding surface 3 fixed side sesame 4 Fixed side lens sesame 4a Molding surface of fixed side lens sesame 5 Fitting recess 6 Fitting convex part 7 Retina Containment 8 Ball Retina 9 balls 10 ball holder 11 Optical lens 12 Guide bush 13 Guide pin

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 2002-36306 (JP, A) JP 7-329133 (JP, A) JP 8-118432 (JP, A) JP 11-144331 (JP, A) JP 2000-167884 (JP, A) JP 2002-254480 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 45/26-45/37 B29C 33/00-33/76

Claims (3)

(57) [Claims] 1. A moving side molding sesame having a stationary side mold and a moving side mold, wherein at least the moving side mold has a moving side lens molding surface, and a movement for holding the moving side molding sesame from the outside. and side holding member, the ball the peripheral wall of the ball holding tube at intervals with a rotatably retained movable ball retainer, and interposed the movable ball retainer between the movable molding sesame and movable holding member And, either one of the moving side holding member or the fixed side die is provided with a fitting recess having a tapered surface on the circumferential surface, and the other side of the fixed side die or the moving side holding member is provided on the circumferential surface. An injection molding die for a plastic optical lens , characterized in that a fitting convex portion having a tapered surface and fitted to the fitting concave portion is provided. 2. The plastic optical lens according to claim 1.
In use the injection molding die, the stationary die, the fixed-side Le
Comprising a fixed side mold sesame with lens molding surface, and the fixed-side holding member for holding the fixed side molding sesame from the outside, a fixed-side ball retainer which is rotatably held at a distance the ball on the peripheral wall of the ball holding tube , plastic, characterized in Rukoto modules inserted through the fixed-side ball retainer between the fixed-side molding sesame and the fixed holding member
Injection mold for optical lenses . 3. The plastis according to claim 1 or 2.
Using an injection molding die for optical lens , the fixed-side die and the moving-side die are joined together, and a molten resin is injected and filled in a cavity formed between the two to mold. To manufacture a plastic optical lens .