# Patent

## Title
Method of manufacturing spectacles with lenses

## Abstract

An object of this invention is to improve the safety. Lens bodies 2, 2a are formed integrally on the rear surface of a shield so as to avoid such a danger that the eyes may be injured due to drop or separation of the lens bodies 2, 2a.

## Background
This is a division of U.S. patent application Ser. No. 10/419 714, filed Apr. 21, 2003 now U.S. Pat. No. 6,890,074.


BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pair of shield type spectacles with lenses which cover both eyes with a piece of shield and manufacturing method thereof.
2. Description of Related Art
Conventionally, a pair of the shield type spectacles which cover both eyes with a piece of the shield made of synthetic resin has been used mainly for occasions of playing sports because it is lightweight, strong and fashionable.
Further, various kinds of shield type spectacles with lenses for adjusting eyesight provided at specified positions have been provided.
Any documents which should be mentioned are not known to this inventor because any survey on related art has not been achieved at a research and development stage or a patent application stage.
However, in conventional spectacles with lenses, its shield and lenses are separated components, and lens bodies formed separately are engaged in through holes made at specified positions of the shield or bonded on the rear face of the shield. Thus, there is such a fear that the lens bodies may drop when a strong impact is received, and therefore this pair of the spectacles with lenses has a problem in views of the safety.
SUMMARY OF THE INVENTION
The present invention intends to solve the problem of improving the safety of the conventional art by forming the lens bodies integrally on the rear face of the shield so as to eliminate a risk that the eyes may be damaged by drop or separation of the lens bodies.



BRIEF DESCRIPTION OF DRAWINGS
FIGS. 1(a) and 1(b) are sectional views obtained when the spectacles with lenses of the present invention are cut horizontally;
FIG. 2 is a front view of a shield with lenses, which is used in the spectacles with lenses of FIG. 1; and
FIG. 3 is a sectional view taken along the III—III of FIG. 2.



DESCRIPTION OF PREFERRED EMBODIMENTS
Hereinafter, the embodiment of the present invention will be described with reference to accompanying drawings.
The spectacles with lenses of the present invention are composed of synthetic resin having excellent light transmission property and impact resistance such as polycarbonate resin and ABS resin and, as shown in FIGS. 1–3, a shield 1 for covering both eyes and lens bodies 2, 2a for adjusting the eyesight are formed integrally with each other.
The shield 1 is formed such that its surface is of a convex curved shape and the lens bodies 2, 2a are positioned at two positions on the right and left of the rear face of the shield 1, that is, at specified positions corresponding to both eyes of a person wearing the spectacles. The surface of each of the lens bodies 2, 2a is formed in a concave shape or a convex shape as shown in FIGS. 1(a), (b).
Next, the manufacturing process for the spectacles with lenses of the present invention will be described in detail.
First, a shield base 4 whose surface is convex and has two convex portions 3, 3a on its rear face, is formed according to a pouring mold polymerization method using monomer such as polycarbonate resin or an injection molding method using thermoplastic resin and then, the shield 1 having a desired shape is cut out from the shield base 4 by cutting off unnecessary portions on an outer periphery of the shield base 4 (see FIGS. 2, 3).
Next, the surfaces of the convex portions 3, 3a on the rear faces of the shield 1 are ground into a concave shape or convex shape so as to adjust its curvature to a predetermined one and then, a shield with lenses 5 in which lens bodies 2, 2a are formed, is obtained (see FIG. 1).
Finally, temples 6, 6a are attached near right and left ends of the shield with lenses 5 and further, nose pieces 7, 7a are attached to the bottom in the center of the shield with lenses 5, so that finally, the shield type spectacles with lenses are formed.
If the spectacles with lenses are formed in the form of sunglasses, for example, pigment is mixed and dispersed appropriately in synthetic resin for formation of the shield base 4, or a transparent shield 5 whose lens bodies 2, 2a are adjusted in terms of their surface curvature is dipped into dye to which dyeing aid is added to raise transparency, so as to dye the spectacles.
If it is intended to make polarizing spectacles with lenses, for example, a concave groove is provided peripherally in the middle portion of an inner face of a cylinder longitudinally separable in a forming process of the shieldbase 4, then a polarizing film is engaged in that concave groove and resin monomer is poured on and under the polarizing film. As a result, the shield base 4 in which the polarizing film is sandwiched between the front and rear surface shields, and the shield with lenses 5 is cut out from the shield base 4.
Although according to this embodiment, the spectacles with lenses, to which the temples 6, 6a and the nose pieces 7, 7a,separate from the shield with lenses 5 are attached, has been described, the temples 6, 6a and the nose pieces 7, 7a may be formed integrally when the shield base 4 is formed.
Because, according to the present invention, the lens bodies 2, 2a are formed integrally on the rear face of the shield 1, the lens bodies 2, 2a never drop or are never separated. Thus, the eyes are protected from a damage due to a disengagement of the lens bodies 2, 2a, thereby improving the safety of the spectacles.
Further, because the quantity of necessary parts is reduced, the manufacturing process is simplified, thereby reducing manufacturing cost and shortening the time for products delivery. Further, because the kind of stocks can be single, management cost can be lowered.
Concerning, the conventional product in which the lens bodies are engaged or bonded to the shield, if the lens bodies are provided on the side of a front surface of the shield in order to prevent a dropped or separated lens body from coming toward eyeballs, a gap is generated on a boundary between the shield and the lens body, so that dust and dirt are deposited in this gap, thereby the spectacles being likely to be contaminated. However, because the present invention has no gap on the surface of the shield 1, it is unlikely to be contaminated and even if stain is attached, it can be wiped out easily.
Because the shield 1 is formed such that its surface is of a convex curved shape, not only a wide field of vision can be secured, but also feeling of fitting to the shape of a wearer's head can be improved.
Because the surface of each of the lens bodies 2, 2a is formed in a concave shape, the lens bodies 2, 2a can be adjusted to a desired degree of lens both for shortsightedness and for farsightedness.
Because the surface of each of the lens bodies 2, 2a is formed in a convex shape, the lens bodies 2, 2a are adjusted to high refraction type, thereby making the lens, bodies 2, 2a thin. Consequently, even if a high degree of lens is required, a sufficient clearance can be secured between the lens bodies 2, 2a and the eyes.
Because the shield 1 and the lens bodies 2, 2a are formed of synthetic resin having light transmission property such as polycarbonate resin and ABS resin, the spectacles can be formed in a lightweight and strong structure, so that they can meet demands in the sport field which entails strenuous activities.
Because the shield 1 is formed such that the polarizing film is sandwiched between the shields on the front and rear surfaces, its dazzlment protection performance is raised thereby expanding a further applicability.
If the spectacles are formed of a material in which pigment is mixed and dispersed, a thick portion becomes dense while a thin portion becomes pale so that entirely unevenness in coloring may occur. However, because the shield 1 and the lens bodies 2, 2a are dyed, it is possible to obtain a sunglass uniformly dyed by allowing dye to penetrate into only a surface portion of each of the shield 1 and lens bodies 2, 2a. Therefore, a practical effect of the present invention is very enormous.

## Claims

1. A manufacturing method for spectacles with lenses comprising:
forming a shield with a single curved outer shape for covering both eyes of a user and having convex portions integral with a rear face thereof, and
grinding rear surface of the convex portions formed integrally on the rear face of the shield so as to adjust the surface of the portions to form lens bodies each having a predetermined curvature.

2. The manufacturing method for the spectacles with lenses according to claim 1 including coloring the shield and the lens bodies with dye.

3. A manufacturing method for spectacles with lenses comprising the steps of:
conducting pouring mold polymerization using a monomer to form a shield base;
cutting out unnecessary portions on an outer periphery of the shield base to form a shield having a single curved outer shape for covering both eyes of a user shape with a convex outer front face and a pair of portions integral with a rear inner face of the shield; and
grinding inner surfaces of the respective portions on the rear inner face of the shield into a concave shape or a convex shape so as to provide lens bodies, each said lens body having a curvature with a predetermined value, wherein spectacles with lenses are formed.

4. The method of claim 3, wherein the shield base is formed in a longitudinally separable cylinder, the cylinder having a concave groove provided peripherally in a middle portion of an inner face of the cylinder, the method including the step of engaging a polarizing film in the concave groove, and
wherein the step of conducting pouring of the monomer comprises pouring a resin monomer on and under the polarizing film so that the polarizing film is sandwiched between front and rear surface shield parts that, in combination, comprise the shield base.

5. The method of claim 3, including the step of dyeing the shield so that dye penetrates into only a surface part of the shield and the lens bodies.

6. The method of claim 3, including the step of attaching nose pieces to the bottom in the center of the shield.

7. The method of claim 3, wherein the pair of portions each have a convex rear face before grinding.

8. The method of claim 3, including the step of attaching temples near right and left ends of the shield.

9. A manufacturing method for spectacles with lenses comprising the steps of:
injection molding with a thermoplastic resin to form a shield base;
cutting out unnecessary portions on an outer periphery of the shield base to form a shield having a single curved outer shape for covering both eyes of a user with a convex outer front face and a pair of portions integral with a rear inner face of the shield; and
grinding inner surfaces of the respective portions on the rear inner face of the shield into a concave shape or a convex shape so as to provide lens bodies, each said lens body having a curvature with a predetermined value,
wherein spectacles with lenses are formed.

10. The method of claim 9, including the step of attaching nose pieces to the bottom in the center of the shield.

11. The method of claim 10, including the step of attaching temples near right and left ends of the shield.

12. The method of claim 9, including the step of attaching temples near right and left ends of the shield.

13. The method of claim 9, including the step of dyeing the shield so that dye penetrates into only a surface part of the shield and the lens bodies.

14. The method of claim 9, wherein the pair of portions each have a convex rear face.

15. The method of claim 9, wherein the shield comprises a single shield.

16. The method of claim 15, including the step of attaching temples near right and left ends of the shield.