DE4311215C2 - Eyeglass lens - Google Patents

Description

The invention relates to an eyeglass lens at least one surface whose surface refractive index increases changes in such a way that seeing into different Ent distances with at least reduced accommodation is possible.

Eyeglass lenses with changing surface power and thus changing total power are generally known:
A bifocal glass is known from the article by Henry A. Knoll "The optical characteristics of beach blended bifocals", printed in American Journal of Optometry 29, 1952, pp. 150-154, in which the transitions between the individual areas are blended "are, so that the refractive index changes approximately continuously. However, such a bifocal glass is only suitable for looking into the distance or in the vicinity, the transition area cannot be used.

From DE-C 28 14 916, to the rest of the explanation expressly refer to the terms used below is taken is a so-called progressive glasses known glass that has a surface with two areas, which have an approximately constant surface power, and between which there is an area with itself continuously changing surface power. The surface breaker By force of the upper area it is dimensioned so that the glasses girder can look into the distance through this area, while the surface power of the lower area is like this is dimensioned that the glasses wearer through this area without or with at least reduced accommodation in the Can look close.

Furthermore, eyeglass lenses that have at least one surface have changing surface power, for which ver various special applications, for example for the Seeing in the cockpit of an airplane has been suggested to which the area laid out to be seen nearby half of the area designed for distant viewing is arranged so that the pilot is above the cockpit window can look at arranged instruments.  

Another suggestion concerns modified close-up glasses, d. H. Glasses that are essentially seen in low and medium distances are intended. According to this suggestion is the Be placed out to see in the distance rich in the central area of the glasses. Above this area decreases the surface power, while below this range the surface power increases takes.

NL-OS 71 07 504 is a multifocal lens known, in which the surface power along a Cut changes continuously, the surface being two cuts perpendicular to each other, the Point symmetrical to their common intersection fen. Because of this structure, seeing in a be agreed removal possible, with a transition part another area is formed, which is used for seeing in a different distance is designed.  

All these well-known glasses and esp especially that from the latter NL-OS 71 07 504 well-known eyeglass lens is common, that for seeing at a certain distance designed areas a more or less large hori have zonal extension, in particular ange the aim is that the "dividing line" between the far part and Progression zone is as horizontal as possible over the entire spectacle lens stretches.

In a number of cases, for example when working at the desk, this training is for seeing Areas or areas located at a certain distance that of the well-known progressive lenses however, there is no horizontal variation in the surface power optimal because, for example, when working on the writing table viewed from the side Objects are usually at a greater distance are located at the central viewing direction or at Looking upward at objects viewed.

The invention has for its object a pair of glasses glass with at least one surface with changing To specify the surface refractive index, which is also seen in areas with at least reduced accommodation enables.

An inventive solution to this problem is in Claim 1 specified. Developments of the invention are the subject of the dependent claims.

According to the invention, an eyeglass lens is specified that two main sections symmetrical to a single point te. Progressive glasses with point symmetry The main lines are only in the beginning time of progressive glass development and here only as  rotationally symmetrical conic surfaces been drawn. At the in recent years Further development of progressive glasses is the direction of development, symmetrical to a point Main cuts to use completely abandoned been.

Surprisingly, it turned out that a surface with two main cuts that symme trical to the same point, for a number of Special tasks, for example for working on Desk or for the purposes of pilots especially are suitable.

According to the invention, an eyeglass lens is now "dot-like metric "main sections developed in such a way that for the radii of the two main cuts in point "0" and at a point 20 mm from the Point "0" applies:

(n-1) _* | (1 / R _{v or h, 0} -1 / R _{v or h, 20} ) | <0.75 D

(n-1) _* | (1 / R _{v, 20} -1 / R _{h, 20} ) | <0.3 dpt

Here, R _{i, 0} and R _{i, 20} with i = v, h are the radii of the main sections v and h at point 0 and the point at a distance of 20 mm from point 0, while n is the refractive index of the glass material is.

Such a spectacle lens can in particular consist of 50 be placed so that there is a peek in the central area allowed nearby. To take a look at the deflection to allow for greater object distances  it preferred if the radii values the main cuts with increasing distance from Increase point zero.

According to the invention, the two main cuts are not identically designed, so the surface is not a rota symmetrical surface. It is especially before moves if not only the Be specified in claim 1 thing, but also in claims 2 and 3 respectively given conditions are met.

In principle, the main cuts can be any aspheric cal curves and in particular also curves that pieced together from different curves are, the curve at the "starting points" twice is constantly differentiable. Here it is possible and at the same time particularly advantageous, the curve in the loading enough to choose the point "0" so that the areas refractive index in an area with at least pupils diameter around the point "0" at least approximately con is constant.

Of course, it is also possible the main cuts as conic sections or as by higher aspheric coefficients modified conic sections form. In the case of the choice of conic sections it is be  preferred if the aspherical coefficients K der Distinguish conic sections by at least 2.5 (claim 7).

It is also used in a number of applications preferred if, according to claim 8, the point "0" as Na belpunkt is formed, d. H. the radius of curvature of the the two main cuts in point zero is the same.

Furthermore, the point "0" must of course not be in the geometric center of the "tubular spectacle lens" lie: So it is possible, for example, the point Arrange zero in the viewpoint for reading distances nen.

The invention is hereinafter without limitation general inventive concept based on execution examples with reference to the drawing exempla risch described on the rest of the Revelation of all not explained in the text explicitly referenced details becomes. Show it:

Fig. 1, the lines of the same mean surface refractive index, and

Fig. 2 shows the lines of the same mean surface astigma for a surface according to the invention.

The area shown as an example has two main parts cuts, one of which is in the x-axis (without Limitation of generality in the figure the hori zonal axis, also denoted by h) and the other in the y-axis (also without restriction of the general the vertical axis, also designated v).  

In this exemplary embodiment, both main cuts have the shape of conic sections, ie the so-called arrow height z (distance of a surface point with the coordinates x, y = 0 or y, x = 0 from the plane z = 0, which the surface in Vertex 0 touched) is given by:

Z _h = C _{h *} x² / (1+ (1- (K _h + 1) _* C _{* h} ² x²) ^0.5
Z = C _{v v *} y² / (1+ (1- (K _v + 1) _* C _* y² _v ²) ^0.5

where mean:
x, y distance of a point on the horizontal or vertical main section from the coordinate origin,
C _{h, v} = 1 / R _{h, v} with R: radius of curvature of the main cut in the apex, and
K _{h, v} conic section coefficient.

In the illustrated embodiment

C _h = C _v = 1 / 103.46 mm

the vertex of the surface is therefore an umbilicus with a surface power of 5.08 dpt at a Refractive index n: 1.525.

The following also applies:

K _h = -7.0
K _v = -4.0.

With this data, the surface has the mean surface refractive index shown in FIG. 1 and the surface astigmatism shown in FIG. 2.

Of course, various modifications are possible within the invention compared to the illustrated embodiment:
So the "point 0" does not have to be an umbilical point, ie the two main cuts can have different curvatures at this point. The main cuts can also be composed piece by piece and differentiated from different functions.

Furthermore, the main cuts can also be one of the Conical shape deviating shape; in particular it is possible to increase the conic equation by terms To add order.

Also, the point "0" does not have to be in the center of the "raw" round "glasses. Ultimately, the oh sen x and y with respect to the horizontal and the vertical len according to the required axis position turns.

Claims (9)

1. Spectacle lens with at least one surface, the average surface refractive index of which changes with different at least reduced accommodation along two mutually perpendicular cuts, which are point symmetrical to their common intersection, and for whose radii R applies: (n- 1) _* | (1 / R _{v, 0} -1 / R _{v, 20} ) | <0.75 dpt (n-1) _* | (1 / R _{h, 0} -1 / R _{h, 20} ) | <0.75 dpt (n-1) _* | (1 / R _{h, 20} -1 / R _{v, 20} ) | <0.3 d and the average surface refractive index along the at least approximately horizontal section decreases with increasing distance from the intersection more than the average surface refractive index along the at least approximately vertical section, whereby
R _{v, 0} and R _{v, 20 are} the radii of the vertical cut at the intersection 0 and at a point on the vertical cut at a distance of 20 mm from the intersection 0,
R _{h, 0} and R _{h, 20 are} the radii of the horizontal cut at the intersection 0 and at a point on the horizontal cut at a distance of 20 mm from the intersection 0, and
n is the refractive index of the glass material. 2. Spectacle lens according to claim 1, characterized in that: (n-1) _* | 1 / R _v or h, o-1 / R _{v or h, 20} ) | <1, dpt (n-1) _* | 1 / R _{v, 20} -1 / R _{h, 20} ) | <0.5 dpt. 3. Spectacle lens according to claim 1 or 2, characterized in that the following applies: (n-1) _* | (1 / R _{v, 20} -1 / R _{h, 20} ) | <0.8 dpt 4. spectacle lens according to one of claims 1 to 3, characterized in that the area around point 0 of the Eyeglass lenses have a surface refractive index that prevents them from seeing the proximity without or with little accommodation of the glasses carrier.   5. spectacle lens according to one of claims 1 to 4, characterized in that the surface power in Be rich around point 0 is at least approximately constant. 6. spectacle lens according to one of claims 1 to 4, characterized in that the cuts have the shape of Have hyperbolas. 7. spectacle lens according to claim 6, characterized in that the aspherical coefficients Distinguish k of the hyperbolas by at least 2.5, where k = ε² and ε is the numerical eccentricity of the hyperbola. 8. spectacle lens according to one of claims 1 to 7, characterized in that the point 0 is an umbilical point is. 9. glasses with a spectacle lens according to any one of the claims 4 to 8, characterized in that the point 0 in the view point is arranged for reading distances.