JPH01243016A - Lens for spectacles and spectacles using said lens - Google Patents

Abstract

PURPOSE:To obtain bifocal spectacles for far and near visions which allow viewing of near and far objects through the entire area of lenses by alternately and concentrically forming reference degree ring bands of a very small width constituting a reference lens face and Fresnel-like ring bands of a very small width constituting an additional degree lens face. CONSTITUTION:This lens has the constitution consisting in spacing each other ring band-like small lenses of the Fresnel lens of the diopter added with the additional diopter to the reference diopter and disposing the reference degree ring bands 3 between these ring band-like small lenses. The respective reference degree ring bands 3 and the Fresnel-like ring bands 4 constitute respectively the lenses having the separate diopters as a whole. The light past the ring bands 3 and the light past the ring bands 3 respectively form images at separate points. The distant view image past the ring bands 3 and the near view image past the Fresnel ring bands are simultaneously formed on the retina in the focused state when the objects are viewed through this lens by the presbyopia. The bifocal spectacles for far and near visions which can view the far and near objects through the entire area of the lens are thereby obtd.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a spectacle lens and spectacles using the same, and relates to a lens having a bifocal function for presbyopes.

[Conventional technology]

In a normal human eye, when the ciliary muscle, which changes the thickness of the crystalline lens, is relaxed, objects are focused at infinity, and by tightening the ciliary muscle and increasing the thickness of the crystalline lens, nearby objects can be clearly focused. The point in focus when the ciliary muscles are relaxed is called the far point, and the point in focus when the ciliary muscles are at maximum tension is called the near point. Focusing on points at different distances is called accommodation, and the degree to which you can focus on points is called accommodation, and when you are young, the crystalline lens itself has a lot of elasticity. Also, because the ciliary muscles are strong, they have great accommodation, allowing us to clearly see objects that are very close up, but as we age, the elasticity of the crystalline lens decreases, and the ciliary muscles also weaken, reducing our ability to accommodate. becomes smaller, making it difficult to see nearby objects clearly (this is what is called presbyopia (officially known as ``presbyopia'').
). Presbyopia is a phenomenon in which near objects become difficult to see due to a weakening of the eye's accommodation ability.
It is necessary to distinguish this from visual acuity loss caused by refractive errors such as nearsightedness and farsightedness. In other words, presbyopic tendencies can occur regardless of emmetropia, nearsightedness, or farsightedness. Presbyoscopes (reading glasses) are used to correct presbyopia and allow you to see things close up. They use a plus (convex) lens to compensate for the lack of bulge in the crystalline lens after adjustment. This lens provides a focal length of 200 cm, and is only worn when looking at nearby objects. In other words, if you wear reading glasses, you will be able to focus on near objects (later on), but you will not be able to clearly see far objects because they are outside the accommodation range of your eyes. It is very inconvenient when you have to look at objects alternately.For example, if a person with emmetropia and presbyopia shifts their eyes from a nearby object to a distant object while wearing a presbyopic mirror, It is common to see people trying to see with the naked eye by moving their reading glasses down with their hands.Also, it is common to see people trying to see with the naked eye.
If a refractive error such as astigmatism and presbyopia overlap, it may be necessary to alternately wear distance-correcting glasses and reading glasses. The above-mentioned inconvenience when using reading glasses has been overcome by the provision of bifocal glasses that allow you to see far through the upper part of the lens and to see near through the lower part of the lens. This is the reason why. The lenses used in such bifocal glasses are called multifocal lenses, and currently, as shown in Figure 1 and Figure 12, the near vision part with a positive (convex) power is located slightly below the lens. As shown in Fig. 13, there are two types of progressive multifocal lenses, in which the power increases smoothly from the distance part at the top of the lens to the middle part and then to the near part as it goes downwards. is frequently used.

[Problem to be solved by the invention]

Of the two types of multifocal lenses mentioned above, the ones shown in Figure 1) and Figure 12 have a distance vision area and a near vision area that are clearly separated. There are many so-called image jumps, where the image rises when you lower your eyes.
Further, when the addition power of the near vision section is large, there is a drawback that the level difference at the boundary between the distance vision section and the near vision section is noticeable from the outside, and the appearance is not necessarily good. In addition, the progressive multifocal lens shown in Figure 13 has a smoothly changing lens surface, so its appearance is not much different from an ordinary eyeglass lens. The above problem has been resolved. However, the middle part that connects the distance vision part and the near vision part or both sides of the near vision part have to be relatively narrow in the distance part that spans the entire width of the lens above the lens and in the lower part of the lens. Since it only plays the role of smoothly connecting the lens surfaces of the
There is a problem in that it is not possible to see through this portion, which occupies a considerable portion of the area of the lens. Furthermore, if you swing your face from side to side while wearing glasses with such lenses, there is a problem in that the image is distorted each time it passes on both sides of the intermediate portion. Also, as can be said about any of the above types of multifocal lenses, the near vision area is only provided in a relatively narrow area below the lens, so you can only move your eyes laterally. It is difficult to read horizontally written text without any trouble, and there is also the problem of having to unnaturally turn one's head upwards in order to see close objects above eye level. In any case, currently available multifocal lenses for spectacles or bifocal glasses that use them still have the above-mentioned problems that need to be solved; This is because they are simply provided at different positions on the lens surface, and the near vision area in particular is provided in an extremely narrow range below the lens. This invention was devised under the above-mentioned circumstances, and its purpose is to solve the problems of conventional multifocal lenses or bifocal glasses using the same at once with a MWa configuration. shall be.

[Means to solve the problem]

In order to solve the above-mentioned conventional problems, the present invention takes the following technical measures. That is, the spectacle lens of the present invention (the invention of claim 1)
has alternating and concentrically formed micro-width reference power (distance) ring zones that form the reference lens surface and micro-width Fresnel-like ring zones that form the addition power lens surface on either the front or rear surface. It is. Then, the lenses are cut into an appropriate shape and fitted into an eyeglass frame to complete bifocal eyeglasses (the invention according to claim 2).

[Action and effect]

Viewed from another perspective, the eyeglass lens of the present invention has one Fresnel lens with a power equal to the reference power plus the addition power, and a reference power zone between each of the ring lenslets. It has a configuration with . Each reference power zone and each Fresnel zone constitute a lens having a separate overall power. In other words, the light that passes through each reference zone and the light that passes through each Fresnel zone focus on different points. When viewed through this lens with presbyopic eyes, a distant image passing through the reference zone appears on the retina;
It is possible to simultaneously form an in-focus image with a foreground image passing through a Fresnel ring. In practical situations, when looking at something close, for example, when reading a document held in hand, there is no distant view where the object to be gazed at is focused near the macula on the retina, so it is difficult to see something nearby. can be seen in focus with presbyopia corrected without any problems. On the other hand, when looking at something far away, there should be nothing blocking it, and there is no near view that is imaged near the macula on the retina. Therefore, you can see distant objects in focus without any problems. Also, even if mll! Even if a distant view image passing through the reference zone and a near view image passing through the Fresnel ring are formed near the macula at the same time, the brain automatically changes the image depending on whether you are looking at a distant view or a near view. There is no problem as it will cancel unnecessary statues. Moreover, in the spectacle lens of the present invention, since the reference zone and the Fresnel zone are evenly distributed over the entire area of the lens, no matter which part of the lens receives the light, A near-view image and a distant-view image can be combined on the retina. Therefore, the problems caused by conventional multifocal lenses in which the near vision area is formed only in a narrow range separated from the far vision area are solved at once. Furthermore, the eyeglass lens of the present invention has a reference zone and a Fresnel zone both having minute widths, and is used in such a way that they are located very close to the eye, where the eye itself cannot focus. Therefore, there is no need to worry about the concentric rings that border each standard degree ring and each Fresnel ring. In addition, unlike the conventional examples shown in FIG. 1) and FIG. 12, there is no possibility that a step is formed at the boundary between the near vision section and the far vision section, resulting in poor appearance. In this way, the spectacle lens of the present invention can be used for presbyopes.
You can see close objects through the entire lens area, and
To provide ideal bifocal glasses that allow you to see distant objects through the entire lens area.

[Explanation of Examples]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is an overall view of eyeglasses 2 using the eyeglass lens 1 of the present invention, FIG. 2 is an enlarged view of section A in FIG. 1, and FIG. Figures ta+ to C1 are schematic cross-sectional views when the spectacle lenses of the present invention are constructed corresponding to emmetropic presbyopia, myopic presbyopia, and hyperopic presbyopia, respectively. As shown in FIGS. 2 and 3, in this example, the lens l
A reference ring zone 3 and a Fresnel-like ring zone 4 are alternately formed on the front surface of the ring. The reference annular zone 3 is made up of a convex spherical part of a lens with a standard power, and the Fresnel zone 4 is formed by each small annular zone of a convex Fresnel lens with a power that is the standard power plus an additional power for presbyopia correction. The structure is similar to that of a single lens. It is preferable that the width of each reference ring zone 3 and each Fresnel-shaped ring zone 4 is as small as possible, but there will be no functional problem as long as the width is such that the rings dividing each ring zone are not noticeable when used as eyeglasses. do not have. Although it is possible with current plastic molding technology to make the width of each ring zone about 0.1 ms or less, even if it is about 0.5 ms,
If you don't care about appearance, it is considered functionally usable. The radius of curvature of the concave spherical surface on the rear surface of the lens l is approximately equal to the radius of curvature of the convex spherical surface of the reference annular zone 3, as shown in FIG. , in the case of myopia and presbyopia, the radius of curvature is smaller than the convex spherical surface of the reference annular zone 3, as shown in FIG.
When used for hyperopic presbyopia, the radius of curvature is larger than the convex spherical surface of the reference annular zone 3 as shown in Figure 4 (C1).Of course, if the rear surface of the lens is a toric surface, it will correspond to astigmatic eyes. When making a plate-shaped lens like the one in this example, you can use hard resin, which is currently used as a material for plastic lenses, as the material. , and has a complicated configuration, we set several types of addition powers for presbyopia correction in the Fresnel zone 3 and made a relatively small number of intermediate products with a constant radius of curvature of the front surface by resin molding. It is considered to be effective in terms of cost to adopt a manufacturing method in which the lens for correcting the refractive error is produced by polishing the rear surface of the eyeglass lens. This will be explained with reference to Figures 5 and 6. As shown in Figure 5, the light that has passed through the reference orbicular zone 3 is the same as passing through, but the light that has passed through the Fresnel zone 4 is from the rear. A real image is formed at a fixed position on the side in the same way as when passing through a convex lens.If this is used as a spectacle lens for presbyopic eyes, as shown in Fig. 6, the light passing through the reference annular zone 3 is A distance image is formed on the retina, and the light that passes through the Fresnel zone 4 forms a near image on the retina.In other words, on the retina, there is a distance image similar to that seen with the naked eye, and a distance image after presbyopia correction. It is possible to combine the foreground image and the foreground image at the same time.As explained earlier, in practice, when gazing at something close, the distant view is obstructed by this, so in reality, the distant view appears on the retina. No image is formed.Also, when gazing at a distant object, there is nothing blocking the distant view, so a near-field image is not formed on the retina.Therefore, depending on whether the object to be viewed is near or far, automatic fishing A focused image is formed on the retina.Furthermore, even if a distant view image and a near view image are simultaneously formed on the retina, the human brain may produce unnecessary images depending on what the person is gazing at. There is no problem because the reference zone 3 and the Fresnel zone 4 each have a very small width, so there is no adverse effect on the appearance of the lens as a whole, and each zone 3 Since the ring formed by ゜4 is close to the eye, this does not bother us. Fig. 7 shows a schematic enlarged cross section of another embodiment of the present invention. In this example, the reference ring zone 3 is In this example, the problem of the thick peripheral part of the lens in bifocal glasses for nearsighted and presbyopic patients is solved by using a one-legged ring as a concave Fresnel lens. It will be easily understood that the same effect as that of the embodiment shown in fbl can be achieved. FIG. 8 shows a schematic enlarged sectional view of still another embodiment of the present invention. In this example, there is an additional power between each reference zone 3 and each Fresnel zone 4 from the Fresnel zone. A small auxiliary Fresnel-like ring zone 4'' is arranged so that objects at intermediate distances of 1 meter and 1 meter from the eye can be seen in focus. A schematic enlarged cross-sectional view of another embodiment is shown. In this embodiment, a portion constituted by alternately arranging reference annular zones 3 and Fresnel-like annular zones 4 is disposed in the lower half region of the lens. The upper half is the normal lens part.This configuration is more convenient for people who may see distant objects through the entire area of the lens, but see nearby objects only through the bottom of the lens. FIG. 10 shows a schematic cross-sectional view of still another embodiment of the present invention. In this example, the reference degree zone 3 and the Fresnel zone 4 are
On the front surface of a lens body 1' equivalent to that shown in FIG.
IT is a charity. This is advantageous because there is no concern that dust will accumulate in the step between the reference ring zone 3 and the Fresnel ring zone 4. Incidentally, since the refractive index of the coating 1'' is smaller than that of the lens body 1', optically equivalent to the embodiment shown in FIG. The present invention is not limited to this. In the embodiment, the reference ring zone and the Fresnel-like ring zone are formed on the front surface of the lens, but conversely, the reference ring zone and the Fresnel-like ring zone may be formed on the rear surface of the lens. This has the effect of greatly improving the front appearance when configured as eyeglasses.

[Brief explanation of the drawing]

FIG. 1 is an overall view of eyeglasses 2 using the eyeglass lens 1 of the present invention, FIG. 2 is an enlarged view of section A in FIG. Cross-sectional view, FIG. 4 [Al to C1 are schematic cross-sectional views when the spectacle lens of the present invention is constructed corresponding to emmetropic presbyopia, myopic presbyopia, and hyperopic presbyopia, respectively; FIGS. 5 and 6 are FIGS. 7 to 10 are schematic cross-sectional views of other embodiments of the spectacle lens of the present invention, and FIGS. 1 to 13 are explanatory views of conventional examples. ■...lens for spectacles, 2...glasses, 3...reference ring zone, 4...Fresnel ring zone.

Claims (2)

[Claims] (1) A feature is that on either the front or rear surface, micro-width reference power zones constituting the reference lens surface and micro-width Fresnel-like zones constituting the addition power lens surface are alternately and concentrically formed. A lens for spectacles. (2) Eyeglasses comprising the eyeglass lens according to claim 1.