JPH0749471A - Spectacles - Google Patents

Abstract

PURPOSE:To make every part of a lens function as a lens for both far and near, so that both objects in far and near directions can be clearly confirmed by the eyes without transferring the visual point of a wearing person itself according to the distance of the object to be observed, by arranging grating elements in a concentric circular or elliptic form on one surface of a spectacle lens so that one lens has multiple foci. CONSTITUTION:In an spectacle lens 2, a form modulated type diffraction grating 5 having an irregular radial section is formed on the back surface side by radially cutting a number of grooves 4 at equal intervals in a concentric circular form having substantially the central point of the lens 2 as the center. In such spectacles, a number of diffracted lights such as zero-order, + or - primary, + or -secondary ... are provided by the diffraction grating 5 in every part of the spectacle lens 2. Thus, the spectacle lens 2 forms a lens for both far and near having a multiple focus. Consequently, a wearing person can focus it to an object to be observed as the visual point 7 of the wearing person remains fixed regardless of the distance to the object, and clearly confirm the object by the eyes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to spectacles, such as reading glasses, having a lens having a plurality of focal points in the perspective direction.

[0002]

2. Description of the Related Art Most conventional eyeglasses of this type use progressive lenses as eyeglass lenses.
In this progressive power lens, as shown in FIG. 6, a distance lens 10 focused on a distant object and a near lens 11 focused on a near object are vertically arranged and cemented together to form a single sheet. The spectacle lens 12 is formed, and a linear joint 13 that crosses the lens 12 is generated at the boundary between the distance lens 10 and the near lens 11.

[0003]

In the conventional spectacles using the progressive focus lens as described above, the wearer's own viewpoint is moved up and down in order to change the focal length according to the distance of the object to be observed. It is necessary to change it, and not only is it troublesome to use it, but because there is a transverse line joint in one lens, when the viewpoint shifts to that joint part, the field of view in front is interrupted for a moment. It is easy to get worn out and feels uncomfortable to wear.

The present invention has been made in view of the above-mentioned circumstances, and it does not generate a seam in the lens, and even if the viewpoint is not changed according to the distance of the object to be observed, It is an object of the present invention to provide glasses in which any of the objects can be clearly seen.

[0005]

In order to achieve the above object, eyeglasses according to the invention of claim 1 are concentric or similar on one surface of a lens for spectacles, with a substantially central point of the lens as the center. It is formed by forming a lattice element having multifocal points in an elliptical shape.

The grating element according to the invention of claim 1 may be one that forms a diffraction grating having an uneven cross section or one that is formed by refractive index modulation.

Further, it is preferable that the surface of the lens on which the grating element formed of the diffraction grating having the uneven cross section is formed is coated with a translucent material having a refractive index different from that of the grating element.

[0008]

According to the spectacles of the invention of claim 1, the concentric or elliptical lattice element formed on one surface of the lens allows
Since it has a multifocal point, any part of the lens becomes a bifocal lens, and it is not necessary to change the viewpoint of the wearer himself according to the distance of the object to be observed. In addition, since the entire area of the spectacle lens is composed of a uniform single lens, no seam that interrupts the field of view occurs.

Further, when the surface of the lens on which the grating element is formed is coated with a light-transmitting substance having a refractive index different from that of the grating element, while maintaining the above-mentioned function of multifocal point, especially the grating element portion of the lens. Can be fully protected.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing eyeglasses according to an embodiment of the present invention. In the eyeglasses 1, eyeglass lenses 2 and 2 are fitted to a pair of left and right lens frame portions 3a and 3a of an eyeglass frame 3, respectively. Become.

As shown in FIGS. 2 and 3, the spectacle lens 2 has a large number of concentric circles centered on a substantially central point of the lens 2 on the back side thereof at equal intervals in the radial direction. By engraving the groove 4, a form-modulation type diffraction grating 5 having an uneven cross-section in the radial direction is formed. As the uneven shape of the diffraction grating 5, various shapes such as a rectangular shape and a sine wave shape can be selected. Such a lens 2 can be manufactured by various known methods such as glass cutting, plastic molding, and photosensitive resin patterning.

In the spectacles 1 having the above-mentioned structure, any part of the spectacle lens 2 is referred to as 0th order, ± 1st order, ± 2nd order, etc. by the diffraction grating 5, as shown in FIG.
A large number of diffracted lights can be obtained. Therefore, the spectacle lens 2 is a bifocal lens having multiple focal points. as a result,
Regardless of the distance of the observation object, the viewpoint 7 of the adherend
It is possible to clearly see the object by focusing on it, even if is kept constant. Further, since the spectacle lens 2 is composed of a single homogeneous lens, no seam that hinders the field of vision does not occur at the boundary between focal lengths.

FIG. 4 is a vertical sectional view of a spectacle lens 2 in spectacles according to another embodiment of the present invention. In this embodiment, a light-transmitting substance such as a transparent resin having a refractive index different from the refractive index of the material forming the diffraction grating 5 over the entire surface on which the diffraction grating 5 including the plurality of grooves 4 is formed. 8
Is coated. Since the unevenness of the diffraction grating 5 is filled with this coating material 8, if the coating material 8 has the same refractive index as that of the diffraction grating 5,
The diffraction grating 5 disappears substantially. Therefore, as described above, the coating substance 8 made of a material having a refractive index different from that of the diffraction grating 5 is used. With this coating material 8, the effect of protecting the diffraction grating 5 can be achieved while maintaining the effect of the multifocal point 6 as in the above embodiment.

FIG. 5 is a vertical sectional view of a spectacle lens 2 in spectacles according to still another embodiment of the present invention. In this embodiment, the refractive index of the material forming the spectacle lens 2 is concentrically modulated to form the diffraction grating 5, and the refractive index modulating means is made of a glass material of which the lens 2 is glass. If the lens 2 is made of resin, a monomer having a different refractive index is concentrically distributed in the resin when the lens 2 is made of resin. It is possible to consider a method of polymerizing after the reaction.

The surface on which the refractive index modulation type diffraction grating 5 is formed may be coated with a protective porous material, as in the case shown in FIG.

Further, although the grating elements 4 are arranged concentrically in each of the above-mentioned embodiments, they may be arranged in a similar elliptical shape centered on the substantially central point of the lens 2. In this case, the ratio a / b of the minor axis a and the major axis b of the ellipse is preferably 0.5 or more, that is, an ellipse close to a circle.

[0017]

As described above, according to the present invention, since the concentric or elliptical lattice elements are arranged on one surface of the spectacle lens, one lens has multiple focal points. Since any part acts as a bifocal lens, any object in the perspective direction can be clearly visually recognized without changing the viewpoint of the wearer itself according to the distance of the object to be observed. In addition, since the entire area of the spectacle lens is composed of a uniform single lens, no seam that interrupts the field of view occurs. Therefore, it is possible to eliminate the inconvenience and discomfort in use of the conventional bifocal glasses with borders.

In the case where the surface of the lens on which the grating element formed of the diffraction grating having the uneven cross section is formed is coated with a light-transmitting substance having a refractive index different from that of the grating element, the multi-layered structure as described above is used. It is possible to sufficiently protect the lens element, particularly the grating element portion, while maintaining the effect of the focal point in practical use.

[Brief description of drawings]

FIG. 1 is a perspective view showing spectacles according to an embodiment of the present invention.

2 is a front view of the spectacle lens in FIG. 1. FIG.

FIG. 3 is a vertical cross-sectional view of the same spectacle lens.

FIG. 4 is a vertical cross-sectional view showing an example in which the lens of FIG. 3 is coated.

FIG. 5 is a vertical sectional view of a lens used in eyeglasses according to another embodiment of the present invention.

FIG. 6 is a front view showing a conventional eyeglass lens.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glasses, 2 ... Lenses for glasses, 4 ... Lattice element, 5 ... Diffraction grating, 6 ... Focus, 7 ... Viewpoint, 8 ... Translucent substance (coating substance).

Claims (4)

[Claims] 1. A spectacle having a multifocal grating element formed on one surface of a lens for spectacles in a concentric circle shape or a similar elliptical shape centered on a substantially central point of the lens. 2. The spectacles according to claim 1, wherein the grating element forms a diffraction grating having an uneven cross section. 3. The spectacles according to claim 1, wherein the grating element is formed by refractive index modulation. 4. The spectacles according to claim 2, wherein the surface of the lens on which the grating element is formed is coated with a translucent substance having a refractive index different from the refractive index of the grating element.