JPS5988718A - Progressive focusing spectacle lens considering vergence of eye - Google Patents

Abstract

PURPOSE:To obtain a comfortable spectacle lens which gives almost the same effect as the naked eye gives, by making the arrangement of the umbilicus-like meridian and the additional refracting power along the meridian to satisfy a prescribed condition. CONSTITUTION:The geometric center of the right eye lens (or left eye lens) Q of farsighted glasses, the meridian passing through a point O, the umbilicus-like merdian passing through the point O, and a point which becomes the maximum additional refracting point on the umbilicus meridian M-M' are represented by O, L-L', M-M', and N, respectively, and the right side (horizontal direction) of the point O (origin) is set as H-coordinate axis and down side (vertical direction) is set as V-coordinate axis. Moreover, the additional refracting power along the umbilicus-like meridian M-M' is represented by D and the displacement to the nose side when compared with a pair of spectacles is represented by H. Then a condition H=AXD+B is made to be satisfied by this lens. The A and B are constants and, for example, 2.5 and 0.0 are respectively adopted to the constants A and B. When the condition is satisfied, a comfortable lens which gives nearly the same effect as the naked eye is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens for IT folk trowels, and particularly to /) Jll?
This invention relates to an improvement in a spectacle lens for presbyopia in which the l power changes progressively.

Presbyopia is a condition in which the crystalline lens in the eyeball lacks elasticity, making it unable to perform the accommodative action necessary for near vision.Presbyopia is a condition in which the lens in the eyeball lacks elasticity, making it unable to perform the accommodative action necessary for near vision. It can be done easily.

By the way, near vision is generally done through the lower part of the eyeglass frame, so if you place the aforementioned convex lens in the lower part of the normal far vision eyeglass frame, you can achieve both near and far vision with one pair of glasses. can be done.

The simplest type of bifocal lens is a bifocal lens. The part of the convex lens for far vision is a small ball, and there are various types in terms of shape, arrangement, use, etc.

However, a common drawback of this type of lens is that when moving from distance vision to near vision, the image suddenly changes in magnification, causing a sense of discomfort. By softening this sudden change and designing a surface that gradually changes the power, we eliminate the sense of discomfort between distance and near, and at the same time, in the boundary area between far and near, we can see intermediate steps! l! ) is a so-called progressive focus lens.

Unlike the 2N thermal point lens, this lens does not have a noticeable boundary line in the near vision area and is difficult to detect as glasses for presbyopia, so it has excellent cosmetic effects.

The % characteristic of this progressive focus lens is that the astigmatism is almost equal to that of the lens from the upper part to the lower part of the center on the lens surface, and the refractive power changes progressively according to a predetermined law. There exists a series of ``belly button soft points'' called ``shaped meridians,'' and the ``belly button soft points'' referred to here are points where the two principal radii of curvature are equal.

This principal radius of curvature is a mathematical term used to express the properties of a curved surface, and it has the following laziness.

In Figure 1, S represents a curved surface, and P is a point on the curved surface S.

is a normal line to the width P on the curved surface S, ν1'', which passes through the point P, and at the point P, the curve in+ S is a straight line.

Here, when the curve where the plane containing the gonads i intersects with the curved surface S is called a concave curve, its cross-sectional curve passes through the point P and can be assumed to have an infinite number of possible shapes. Among the radii of curvature at the point P of each cross-sectional curve, the two, the maximum and the maximum /J\, are the principal radii of curvature added to the point P.

When these two principal radii of curvature are equal, the point P is called a umbilicus soft point. Therefore, a spherical surface is the only curved surface where any point on the curved surface becomes a navel soft point J, and in this case, the idle curve on the curved surface can become the above-mentioned "navel-like meridian."

Now, since the vicinity of point P, which is the navel soft point, can be considered to be a $j urban spherical surface, the astigmatism at point P is considered to be equal to zero. Here, 1- Astigmatism is the difference between the two principal radii of curvature mentioned above when they are replaced by refractive power, and here it is important to convert the radius of curvature to refractive power in diopters. , D: Refractive power (unit: diopter) R: Radius of curvature (unit: m) N: Refractive index of lens (unit: m).

Now, in the above explanation, it was assumed that the ``umbilicus-shaped meridian'' exists on the lens surface from above to below Sochu.

As mentioned above, the astigmatism along the ``umbilicus meridian'' is almost zero, and it has the best optical properties on the surface of a progressive lens, and is naturally the most commonly used. It should be placed in a frequently used position.

The present invention provides a completely new regularity that did not exist in the past in relation to the arrangement of this "umbilicus-shaped meridian" and the corresponding additional refractive power along the "umbilicus-shaped meridian". The purpose is to provide a comfortable eyeglass lens that is close to the condition seen with the naked eye.

Now, the desirable position of this "umbilicus-shaped meridian" on the surface of the mirror lens is that the eyeglass wearer is looking at the infinite distance of the frontal force, and the frontal force is located at the lower edge of the frontal force. When you turn your eyes to the near-field viewing state, consider a school building that matches the position on the surface of the spectacle lens through which vision #: J1 passes.

In Figure 2, sushi and 01 are respectively on the right u1-. , the center of rotation of the left eyeball (B), O,, OL, the cornea of the right eye and the left eye, respectively. ) T is the target point at infinity in front of the front in binocular vision P is the intersection of TOR and the surface of the spectacle lens, F is the leg of the perpendicular line drawn from P to ■○□, G is the Assuming the foot of the perpendicular line drawn from T to IJLOR,
Since TOR and TG are parallel, <GTOR-<POR
F, and let this angle be θ.

Now, when the right eye changes from the state where it is looking at ■ to the state where it is looking at T3, the amount of displacement of the 'a-line passing position on the spectacle lens surface becomes 100 due to the 4III8 light effect of the eyeball. Here, the accommodation power of the eyeball is D8, and the continuous refractive power of the eye stitch is Y.
D., If the add refractive power at the point PK of the glasses is p, then
Since the distance from the eyeball to the optotype T is acceptable (the unit of refractive power is diopter, the unit of length is m1 or less), generally To Therefore, if the additional refractive power at the point P of the glasses is D, then UR is obtained.Here, considering that 7 and π-1Do are almost constants, 4. Therefore, it can be seen that by setting PF = H, A is a proportionality constant, and B is a constant, it can be expressed as H;AxD+B.

As for the arrangement of the ``umbilical meridian'' mentioned above and the distribution of the additional refractive power, let us calculate the additional refractive power along the ``umbilical meridian'' and the amount of displacement to the true piece compared to the common part. It can be said that it is most desirable that A be a proportional constant and B be a constant so that H satisfies the coefficient 1 of AXD+B.

The above description is about the right eye, but the same applies to the left eye.

FIG. 6 and Table 1 below show one embodiment of the present invention.

In Fig. 6, Q indicates the right eye lens viewed from the convex side, and point 0 is the central point of the lens. L - L' is the meridian that passes through point O, M - M' is the umbilical meridian that follows O, and point N is M
1 (coordinate axis (horizontal displacement amount)
, when the lower side is the V coordinate axis (vertical displacement), the H and ■ coordinates of point N are HmaxlVmax and '
Fru. The graph on the right side of Figure 3 is the umbilical meridian M - M'
represents the additional refractive power along the point Q′ corresponding to point O
From the origin, the coordinate axis is to the right (additional refractive power)
, when the lower side is the V coordinate axis (displacement in the overlapping direction), point N
Let Dllax be the D coordinate of point N' corresponding to . Dm
aX is generally called the addition power, and in this example, it is 1.0.
0 geositer.

Also, V = 12. OB, HI]]a! =2.5wL
Then aX, D on M - M' corresponding to V coordinate every 2.01B
The coordinates and H coordinates are listed in the first column below.

As is clear from Table 1, in this example, A = 2.5 and B = 0.0 are used for the above-mentioned H product AXD+BK. .

In addition, the left-eye lens has mirror symmetry with respect to the right-eye lens, that is, the refractive surfaces are arranged in a similar manner, with the upper and lower directions being the same and the left stone direction being opposite, as if reflected in a brocade pattern.

In addition, in this example, M −1? to which the present invention is applied? 'In the upper section, the distribution of additional bending force is 0. Although the entire range from O to the number of subscribers has been adopted, it is also possible to use only a portion of the range.

Therefore, an eyelid lens to which the present invention is applied to a section on M-M' having a change in refractive power of at least 80% or more of the number of additions is included within the scope of the claims of the present invention. do.

Also, the "umbilical point" and "umbilical meridian" used in the text
This definition is just a mathematical definition, and it goes without saying that it cannot completely appear on the surface of eyeglass lenses, which are industrial products. Therefore, defects in manufacturing and measurement may occur.
Even if there is an astigmatism of less than 10.25 diopters, the error bias due to drag force is considered to be within the scope of the claims of the present invention. .

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the umbilical point and the principal radius of curvature, and Fig. 2 is an illustration of the optotype, eyeball, and FIG. 6 is an explanatory diagram showing the relative positional relationship of spectacle lenses, and FIG. 6 is a front view of a spectacle lens according to an embodiment of the present invention, and schematically shows the arrangement of the umbilical meridian and the distribution of added refractive power. 456° in the explanatory diagram Representative Asamura Kōgai 4 people 2

Claims (1)

[Claims] (1) When the refractive surface is viewed from a direction substantially perpendicular to the refractive surface when one of the two refractive surfaces of the spectacle lens is aligned with the vertical direction of the lens when worn, One pseudo meridian +WM-M' defined as the "umbilicus-shaped meridian" in the vertical direction within the refractive surface
, and the principal radii of curvature at any point on the umbilical meridian M-MI are equal to each other, so that along the umbilical meridian M-M' in the refractive surface, The astigmatism at all points is almost equal to zero, and the distribution of refractive power along the umbilical meridian M-M' within the refractive surface follows a predetermined law from top to bottom, It has a gradually increasing section, and the way the refractive power changes in the section is not uniform, and furthermore, the umbilical meridian a
M-M' divides the refractive surface into two lateral parts, a side part and a temporal part when worn,
At the top within the refractive surface, the umbilical meridian M - M
Assuming a single meridian L-L' that coincides with, intersects with, or touches ' and extends vertically, in the lower part of the refractive surface, the umbilical meridian M-M' is the same as the meridian L-L.
', and in the range from the upper part to the lower part, the umbilical meridian M-M' is the meridian L-L'.
On the other hand, in the refractive surface having the umbilicus-shaped meridian M-M' that gradually shifts toward the nasal side from above to below, the refractive power on the umbilicus-shaped meridian M-M' at any point on the umbilical meridian M-M' in a section on the umbilical meridian M-M' in which the amount of change is at least 80% or more of the addition power of the working foot of the lens. Let the additional refractive power at the point be D, and the meridian L − of the arbitrary point
When the displacement t from L' is H, A is a proportionality constant, and B is a constant, H: AXD + B. A lens for progressive focus glasses that takes into account fir, (2. In the lens of claim 1, the astigmatism along the umbilical meridian! M-M' exceeds zero and is 0.2
A lens for progressive focus glasses, characterized in that it has a diameter of 5 diopters or less.