JP2008185695A - Far and near bifocal lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure not only excellent appearance but also an excellent visual field by hardly having a step on an eye face and an objective face. <P>SOLUTION: The whole region of the objective side face 1 of a far and near bifocal lens for eyeglasses is prepared at a fixed curvature, and concerning the eye face 2, an upper side and lower side are made different in curvatures. By the mutual relationship of the curvatures of the objective face 1, the whole objective face is smoothed without any projection part and any step by preparing the curvatures of the eye faces 2a, 2b in each region respectively so that the upper side is a region F for myopia correction and the lower side is a region N for hypermetropia correction. Furthermore, light is largely refracted after passing a polarizing film 3 to correct hypermetropia without largely reflecting light before passing the polarizing film 3 by embedding the polarizing film 3 in an intermediate part between the objective face 1 and the eye face 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a perspective bifocal lens for spectacles.

Conventionally, when a spectacle lens is made of plastic, for example, a catalyst is added to a monomer of a thermosetting resin, and then injected into a predetermined mold and heated to polymerize and cure the monomer in the mold. It was formed by the casting polymerization method.
And when it is set as a perspective bifocal lens, a ball lens (lens for myopia correction) and a small lens smaller than this are produced by the above method, and the objective surface of the ball lens (surface facing the object to be viewed) A small lens is affixed to the surface, or only a ball lens is produced, the objective surface is polished, two regions having different curvatures are formed on the objective surface, and a gentle portion with a small curvature is defined as a region for correcting myopia. In addition, a region having a large curvature and projecting in the direction of the visual object is used as a hyperopic correction region.
In the case of a glass lens, a similar method is used to make a perspective bifocal lens.

  We do not conduct prior art searches at the research and development stage or application stage, and do not know the prior art documents to be described.

However, the conventional perspective bifocal lens is not preferable in terms of appearance because it has a region for correcting hyperopia on the objective surface of the spectacle lens that is visible to other people when wearing spectacles and can be said to be part of the human phase. There was a step at the boundary between the myopia correction region and the hyperopia correction region, and this step hindered the field of view.
In addition, when a polarizing function is imparted to this perspective bifocal lens, it is common to embed a polarizing film in the middle part between the objective surface and the eye surface. There was a phenomenon that the translucency was lowered and the color was slightly blurred.
This is because light passes through the objective surface of the hyperopic correction region having a large curvature and is refracted greatly when entering the lens, and then passes through the polarizing film. It is thought that the light is scattered and caused as a result.
By the way, the same phenomenon does not occur in the myopia correction area because the curvature of the objective surface is small in the myopia correction area and the polarizing film is embedded almost parallel to the object plane of the myopia correction area. This is because the incident light generally faces the polarizing film.

  In view of the above problems, the present invention adjusts the entire area of the objective surface of the perspective bifocal lens for spectacles to a constant curvature, while the curvature of the upper and lower sides of the eyepiece surface is different, By adjusting the ocular curvature in each area so that the upper side is the myopia correction area and the lower side is the hyperopia correction area depending on the relative relationship with the curvature of the object plane, Make it smooth with no steps, and embed a polarizing film in the middle between the objective surface and the eye surface, so that the light does not refract significantly before passing through the polarizing film, and after passing through the polarizing film. The above-mentioned problem is solved by refracting the light largely and correcting hyperopia.

In short, the present invention is a perspective bifocal lens for spectacles, wherein the entire area of the objective surface is adjusted to have a constant curvature, while on the opposite side, the curvature is different between the upper side and the lower side, The curvature of the eye surface in each area is adjusted so that the upper side is the area for correcting myopia and the lower side is the area for correcting hyperopia.For example, the objective surface is convex. The eye surface is formed in a concave shape, and the curvature of the objective surface is adjusted to be smaller than the curvature of the upper side of the eye surface, and further the lower side of the eye surface is compared with the curvature of the object surface. Since the curvature is adjusted to be small, both the eye-facing surface and the objective surface have no steps, and not only the appearance is good, but also a good field of view can be secured.
In addition, because there is no step, even if the product of the present invention is decorated by dyeing, for example, the dye is evenly blended and finished with no color unevenness, and it is beautifully finished. Wiping off is extremely easy.

  The object surface is convex and the upper side of the eye surface is concave, and the curvature of the object surface is adjusted to be smaller than the curvature of the upper side of the eye surface, and the lower side of the eye surface is convex. In the hyperopia correction area, both the object plane and the eye plane are convex, and the transmitted light can be refracted more greatly, so that the curvature of the object plane can be set large even when the addition power is increased. The lens thickness can be reduced.

  Since a polarizing film is embedded in the middle between the objective surface and the eye surface, light transmission abnormality does not occur, light transmission deterioration can be avoided, and better visibility can be secured. The effect is significant.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of a perspective bifocal lens according to the present invention, and FIG. 2 is an end view taken along the line AA of FIG.
In FIG. 2, the left side is the object plane (surface facing the object to be observed) side, and the right side is the eye-facing surface (surface facing the human eye) side.

As shown in each figure, the perspective bifocal lens of the present invention basically adjusts the entire area of the object surface 1 to a constant curvature, while the eyepiece surface 2 has a curvature on the upper side and the lower side. The upper side is an area for correcting myopia F (the portion above the one-dot chain line in FIG. 1) and the lower side is an area for correcting hyperopia N (the one below the one-dot chain line in FIG. 1). The curvatures of the face-to-face surfaces 2a and 2b in each region are respectively adjusted so as to be part.
Hereinafter, an Example is shown and it explains in full detail.

As shown in FIGS. 1 and 2, the perspective bifocal lens of Example 1 is formed by forming the objective surface 1 into a convex shape and the eyepiece surface 2 into a concave shape. The curvature of the object surface 1 is adjusted to be smaller than the curvature of the eye surface 2a), and the curvature of the lower side of the eye surface 2 (the eye surface 2b) is adjusted to be smaller than the curvature of the object surface 1. ing.
In this way, by setting the curvature at each part, the light beam focal point coincides with the adjustment far point of the myopic eye on the upper side, and the light ray focal point coincides with the adjustment far point of the presbyopic eye on the lower side.

As shown in FIGS. 1 and 3, in the perspective bifocal lens of Example 2, the object surface 1 is convex, the upper side of the eye surface 2 (the eye surface 2a) is concave, and the eye surface 2 The lower side (opposite surface 2b) is formed in a convex shape, and the curvature of the interocular surface 2a must be larger than the curvature of the objective surface 1 as in the first embodiment. What is necessary is just convex, and what is necessary is just to set suitably by the desired addition power irrespective of the magnitude of the curvature on the basis of the curvature of the objective surface 1. FIG.
Thus, by making the hyperopic correction region N biconvex, the transmitted light is largely refracted in the convergence direction.

  When imparting a polarizing function to the product of the present invention, as before, at the time of molding the lens substrate, a polarizing film is previously attached to a predetermined location in the mold, and a molding material is injected into such a mold, What is necessary is just to embed the polarizing film 3 in the intermediate part of 1 and the eye-facing surface 2.

  The molding material may be plastic or glass as before, and the curvature adjustment method is also appropriate. For example, all of the objective surface 1 and the eye surfaces 2a and 2b are set to a predetermined curvature when the lens base material is molded. Alternatively, the lens base material in which only the objective surface 1 is molded to a predetermined curvature may be produced, and the eye surface 2 of this lens base material may be polished to prepare the eye surfaces 2a and 2b. Alternatively, a plate-shaped lens base material may be formed, and all of the objective surface 1 and the eye surfaces 2a and 2b may be prepared by polishing. In short, the curvature of each surface to be set according to the desired addition power It may be appropriately selected depending on the manufacturing convenience such as easy and non-demolding.

1 is a front view of a perspective bifocal lens according to the present invention (Examples 1 and 2). FIG. (Example 1) which is AA cut part end elevation of FIG. (Example 2) which is AA cut part end elevation of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Objective surface 2 Opposite surface 3 Polarizing film F Area for myopia correction N Area for hyperopia correction

Claims (4)

  This is a perspective bifocal lens for spectacles, which adjusts the entire area of the object surface to a constant curvature, while the opposite eye surface has a different curvature on the upper side and the lower side, and is relative to the curvature of the object surface. A perspective bifocal lens in which the curvature of the ocular surface in each region is adjusted so that the upper side is a myopia correction region and the lower side is a hyperopia correction region.   The object surface is convex and the eye surface is concave, and the curvature of the object surface is adjusted to be smaller than the curvature of the upper side of the eye surface, and the object surface is further compared to the curvature of the object surface. 2. A perspective bifocal lens according to claim 1, wherein the curvature on the lower side of the eye surface is adjusted to be small.   The objective surface is convex, the upper side of the eye surface is concave, and the lower side of the eye surface is convex, and the curvature of the object surface is smaller than the curvature of the upper side of the eye surface. The perspective bifocal lens according to claim 1, which is prepared.   4. The perspective bifocal lens according to claim 1, wherein a polarizing film is embedded in an intermediate portion between the objective surface and the eye-facing surface.

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