JP2594817Y2 - Gasket for plastic lens polymerization - 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 used for polymerizing a plastic lens, and more particularly to a gasket thereof.

[0002]

2. Description of the Related Art For polymerization molding of a plastic lens, a mold is used in which a pair of molds made of glass or ceramics is held at a required interval by an annular gasket. A plastic lens having a required shape can be obtained by filling a plastic monomer into the mold and performing heat polymerization.

Generally, a plastic lens formed by polymerization is coated on its surface with a hard coat film. This coating is performed by holding the polymerized lens in a dipping frame and dipping (immersing) in a hard coat liquid. However, the outer peripheral cylindrical surface (edge portion) of the conventional polymer molded lens has a simple flat cylindrical shape and is slippery, so that the holding by the dipping frame tends to be uncertain. Could fall. Further, when the lens is pulled out of the liquid, the coating liquid collects in the form of water drops at the lowest part of the lens edge. If this water-drop-form coating liquid is dried as it is, it becomes a convex part, and therefore, some removal work is required.

[0004]

The object of the present invention is to obtain a gasket shape capable of molding a plastic lens which has been molded and molded so that the lens can be securely held when post-processing such as dipping. Aim. It is another object of the present invention to obtain a gasket shape that enables a lens to be formed into a shape in which a dipping liquid does not become a convex part even when the dipping liquid accumulates in the lowest part of the lens edge part.

[0005]

[Outline of the invention] The invention is based on the inner peripheral surface of a conventional gasket,
In other words, the idea that the surface that determines the edge shape of the superposed molded lens was a simple cylindrical surface was modified, and by forming a convex portion on this surface, a concave portion was formed in the edge portion of the superimposed molded lens. It was completed based on this. That is, the present invention provides a plastic lens polymerization mold including a pair of molds and an annular gasket that determines the distance between the pair of molds, and the inner peripheral surface of the annular gasket includes:
A substantially annular convex portion having a V-shaped cross-section located substantially in the middle of the pair of molds, and a cross-section corresponding to the annular convex portion on the periphery of a plastic lens formed by the pair of molds and the annular gasket; It is characterized in that an annular convex portion forming a V-shaped annular concave portion is formed. The annular V-shaped convex portion formed in the annular gasket as described above allows
When a concave portion having a V-shaped cross section is formed in the edge portion of a lens to be polymerized and molded, not only the holding performance of the lens is enhanced, but even if the dipping liquid accumulates in the lowest portion of the lens edge portion, it does not become a convex portion.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a sectional view of a mold 10 having a gasket according to the present invention. The mold 10 includes a pair of flat and circular glass molds 11 and 12, and the glass mold 1
An annular gasket 13 for holding the first and the second at predetermined intervals
It consists of At both ends of the gasket 13, large-diameter cylindrical portions 13a and 13b for fitting the glass molds 11 and 12 are formed, and between the large-diameter cylindrical portions 13a and 13b, the glass molds 11 and 12 are formed. And a small-diameter cylindrical portion 13c located therebetween is formed. On the inner peripheral surface of the small-diameter cylindrical portion 13c, there is formed an annular convex portion which is a feature of the present invention, and a projection 14 having a V-shaped cross section in the illustrated example. The upper and lower end surfaces of the small-diameter cylindrical portion 13c are
The radius of curvature is the same as the radius of curvature of the glass molds 11 and 12.

[0007] A plastic monomer is charged into the mold 10 having the above-described structure by a known means, and when this is heated and polymerized, a plastic lens corresponding to the shape of the mold 10 is polymerized. FIG. 2 is a side view of the plastic lens 15 formed by polymerization, and its edge (outer peripheral cylindrical surface) 15a has an annular V corresponding to the V-shaped projection 14.
A groove 16 is formed.

When the plastic lens 15 is next dipped in the hard coat liquid, the plastic lens 15 is held by the dipping frame 17, and the dipping liquid (hard coat liquid)
8 immersed. The dipping frame 17 has an annular V
A projection 17a corresponding to the groove 16 can be formed, and the engagement between the projection 17a and the annular V-groove 16 allows the plastic lens 15 to be held without fear of falling off.

When the plastic lens 15 is pulled up from the dipping liquid 18 together with the dipping frame 17 after immersion, the hard coat liquid tends to form a water-drop-like liquid pool at the lowest part of the edge portion 15a. However, the annular V groove 16
Has the ability to hold the hard coat liquid by the surface tension of the liquid, so that the liquid pool can be prevented from protruding from the edge portion 15a. Therefore, it is not necessary to take special measures for preventing liquid pooling. Further, at the time of lifting, the hard coat liquid in the edge portion 15a does not flow out to the lens surface but flows through the annular V-groove 16, so that it is possible to prevent excess hard coat liquid from remaining on the lens surface.

FIGS. 3 and 4 show another example of the shape of the gasket according to the present invention. The gasket 13A in FIG.
The cross-sectional shape of the cylindrical portion located between the glass molds 11 and 12 is rectangular, and the glass molds 11 and 12 have
Formed are flat portions 11a and 12a that contact upper and lower end surfaces of the rectangular cross-section tubular portion 13d, and fitting portions 11b and 12b that fit into the inner peripheral surface of the rectangular cross-section tubular portion 13d.

The gasket 13B shown in FIG.
The portion where the glass mold 11 of FIG.
e, and the portion where the glass mold 12 contacts is a trapezoidal shape 13f.
This is an embodiment of the present invention. In any of the embodiments, a V-shaped projection 14 is formed on the inner peripheral surface of the small-diameter tubular portion 13c or the rectangular-section tubular portion 13d. In short, the present invention does not ask the entire shape of the gasket 13,
It is sufficient that the V-shaped protrusion 14 is formed on the inner peripheral surface of the cylindrical portion located substantially in the middle between the glass molds 11 and 12. Note that the V-shaped projection 14 does not necessarily have to extend along the entire circumference of the cylindrical portions 13c and 13d.

[0012]

As described above, according to the plastic lens polymerization gasket of the present invention, a concave portion having a V-shaped cross section can be formed at the edge of the plastic lens to be polymerized. Therefore, when performing post-processing such as dipping,
Not only can the lens be reliably held, but even if the dipping liquid accumulates at the lowest part of the lens edge, it does not become a convex part, so that there is no need to remove this liquid pool.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a plastic lens polymerization mold having a gasket according to the present invention.

FIG. 2 is an explanatory view schematically showing a lens formed by polymerization using the mold shown in FIG. 1 and a dipping state of the lens.

FIG. 3 is a sectional view of a plastic lens polymerization mold having a gasket of another shape according to the present invention;

FIG. 4 is a cross-sectional view of a plastic lens polymerization mold having a gasket of still another shape according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Mold 11 12 Glass mold 13 13A 13B Gasket 13a 13b Large-diameter cylindrical part 13c Small-diameter cylindrical part 13d Rectangular cross-sectional cylindrical part 14 V-shaped projection 15 Polymerized plastic lens 15a Edge 16 Ring V groove 17 Dipping Frame 18 Dipping liquid

Continuation of the front page (72) Inventor Takao Fujisawa 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Asahi Optical Industry Co., Ltd. (56) References JP-A-59-106936 (JP, A) JP-A-4- 232706 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 39/00-39/44 B29C 33/00-33/76 B29D 11/00

Claims (1)

(57) [Scope of request for utility model registration] 1. A plastic lens polymerization mold comprising: a pair of molds; and an annular gasket for determining an interval between the pair of molds, wherein an inner peripheral surface of the annular gasket is substantially free of the pair of molds.
It is a solid annular convex part with a V-shaped cross section located in the middle.
Formed by these pair of molds and annular gasket
Corresponding to this annular protrusion on the periphery of the plastic lens
A plastic gasket for polymerizing plastic lenses, wherein an annular convex portion forming an annular concave portion having a V-shaped cross section is formed.