JPS5824115A - Progressive multifocus lens - Google Patents

Abstract

PURPOSE:To use one kind of lens as left and right lenses of a pair of spectacles, by constituging so that a sectional curve falling at right angles with a main meridian curve is >=2.5mm. from the main meridian curve in a far use part area, and has a circular shape. CONSTITUTION:A far use center A of a progressive multifocus lens is positioned in the geometrical center of the lens, and a border line C1 between a far use part area and an intermediate part area is horizontal. Also, width of a spherical area D in the far use part area is >=2.5mm. from the main meridian curve, and in area D1 of its outside, as it is separated from the main meridian curve, a curvature in the horizontal direction increases. In other, words, a sectional curve falling at right angles with the main meridian curve is >=2.5mm. from the main maridian curve in the far use part area, and forms a circular shape. According to this invention, it is unnecessary to make a lens asymmetrical in order to eliminate astigmatism on the vision center line, and one kind of lens can be used as left and right lenses of a pair of spectacles.

Description

[Detailed description of the invention] The present invention relates to the shape of a refractive surface of a progressive multifocal lens.

The purpose of the present invention is to suppress astigmatism and distortion that inevitably exist in progressive multifocal lenses as much as possible, and to create a thread path multifocal lens that provides the most satisfaction to its users when used in various situations. t-To be present. Another purpose is to facilitate the shape elliptic tube j] in the lens manufacturing process, and v! The objective is to reduce the lens insertion error [2 and the fitting precision 1f' for the user's eyes when set to 1-.

In order to facilitate implementation of the present invention, we will explain the use, structure, and optical characteristics of a progressive multifocal lens.

JFI Shinta Shinko's focal lens was developed as the king of focusing lenses in order to reduce the decrease in eye lens adjustment mechanism No'ft pressure in the elderly. There is an area for seeing things nearby, and an area for seeing things at an intermediate distance with degrees that change continuously into darkness in the inner area.

These S areas are respectively distance vision area, near vision t@5 area,
It is called the intermediate region. FIG. 1 shows the general preparation of a progressive multifocal lens, and is a perspective view of a convex refractive surface.

The opposite concave surface (not shown) is made into a spherical or cylindrical curved surface, so that it is farsighted or myopic. and astigmatism correction. This is the optical center axis (hereinafter referred to as the original axis) of the 1μ lens in the figure,
Passing through the geometrical center 0 of the lens, 2 is the principal meridian curve that is the intersection of the perpendicular plane 5 containing the light @1 (hereinafter referred to as principal meridian plane) and the refractive surface of the lens. Figure 2 shows changes in the curvature of this principal meridian curve.The vertical axis of the figure is the distance along the principal meridian curve, and the horizontal axis is the Pr1 surface refractive power (the value of the refractive effect due to the convex refractive surface). (This is called the slight refractive power of the refractive effect of the lens including the concave surface.) The plane rupture force along the principal meridian curve is constant above point A and below point B, and increases progressively from point A to point B. These points A and B are called the distance center and the near center, respectively, and the amount of change in the dark plane layer rupture power (ADD in the figure) tl;C addition is called. Since the surface layer rupture power and the curvature of the lens are proportional η, this figure can be regarded as a change in curvature, and the locus of the center of curvature of the principal meridian curve is the first
It becomes as shown by 3 in the figure. Also, each point 'C on the principal meridian curve
The curvature in the direction perpendicular to the principal meridian curve and the direction along the same curvature; it is a so-called navel-shaped curve, and the astigmatism on the principal meridian curve is zero. , it forms an almost spherical shape in the convex part of the principal meridian curve.However, in order to connect spherical surfaces with different curvatures to form one clean and smooth curved surface, as it moves away from the principal meridian curve, it becomes aspherical. As a result, astigmatism will occur in the periphery.Furthermore, since the magnification differs by /i!rg in refraction (2), distortion of one image also accompanies it.

FIG. 3 shows the distribution of astigmatism of a progressive multifocal lens.

In the figure, the narrower the hunting pitch, the greater the aberration. In other words, it means that the image is blurred.
Generally eight people perceive astigmatism, and the discomfort t-m is α5
It is said to be more than a diopter (hereinafter abbreviated as D), and in the area of no/1 tsuching in the figure (area of less than L5D).This orchid area above point A is the distance clear vision area, and B This region below the point is called the near clear vision region, and this dark region from point A to point B is called the intermediate clear vision region, and is the range in which objects are perceived to be clearly visible at each distance. Figure 4 shows the distortion of an image when a grid pattern (hereinafter referred to as a square grid) drawn at equal pitches in the vertical and horizontal directions is viewed through a progressive multifocal lens. , as shown in the figure, the main meridian curve t'' is vertically close (41 in the figure)
It bulges downward with the center at the center, and the horizon curves toward the periphery. This distortion Sa is not only perceived as my own distortion, but also when the user focuses his/her eyes on a moving object, or when the user's neck moves, etc. In some cases, it is perceived as image shaking, causing discomfort. This is how I recommend<w'i
When you look at something, it's called tm-like observation, whereas when you read a book or stare at one point, it's called aft! When there is no difference between A and the movement of objects, it is called tS vision. As is clear from the above explanation, static vision is primarily affected by astigmatism. In other words, the wider the distance, near, and intermediate clear vision ranges, and the smaller the overall astigmatism, the more comfortable vision is expected. - 10,000, as a dynamic visual a king, is affected by image distortion. In other words, the smaller my distortion is, the more comfortable vision I can get with less distortion. The relationship between static vision and dynamic vision is not independent, and if we widen the clear vision range in order to obtain good static vision, the change in magnification will be rapid on the @ side of the lens. Distortion increases, impairing dynamic vision, and conversely, improving dynamic vision increases astigmatism in the distance and near vision regions, impairing static vision. They have a contradictory relationship.

In this way, the present invention is designed to minimize the astigmatism and image distortion that inevitably exist in progressive multifocal lenses, and provide the best dynamic vision for elliptical static vision conditions: I! Nihide-
A progressive multifocal lens as shown in 171569 of 1982 was developed. Figure 5.6.7 explains the #I structure of the refractive surface of the progressive multifocal lens. Figure 5 shows a front view. , FIG. 7 is a -it perspective view of the refractive surface. Figure 5 KB, 01*02ij intersects with the principal meridian 4 mm at distance center A and near center B, respectively, and the lens refraction l is 3
#HU- to be divided into areas 51 and 52653?
Distance S area, near area, and heavy cloth 11i Shenzhong Pavilion S, respectively.
It's a matter of anger. Ml is a cross-sectional curve by a plane parallel to the principal meridian curve edge, and the points of intersection with the curve C11C2 are respectively A
1. Let it be B1.

Figure 6 shows changes in the angle between the normal to the lens refractive surface and the principal meridian plane at each point on the curved edge M1.
In FIG. 7, which is easy to understand from the perspective view of FIG. 7, P 1 * P 2 * P S has the distance and the middle q! on the cross-sectional curved edge M1! For points in the r1iI region, the modulus of each point -
The angle formed by T1*T2*T5 and Oji Senmen 71 [K1. to 2
．． This is indicated by 3. One of the object images of this lens is that this angle, as shown in Figure 6 (the vertical axis is the position on the curved edge M1, the horizontal axis is the angle), is the distance area (the area where the main force is stronger than A1) and the near area. S
Each value is constant in the region (the part of the lower blade from B1), and it changes continuously and smoothly in the middle region (A 1 : l) m to B1), and one force changes the value of that change. This is somehow the same as the law of change in curvature on the principal meridian.

This is satisfied for all cross sections parallel to the main meridian circle. ! @8 In one cross section in Figure 8,
i In the diagram showing the change in angle f mentioned above, M1*M2 M5IM
Main meridian tune 11 in the order of 4! It shows the angular change in the cross section moving away from the point. This vertical lri[1[I song #1
Since the change in angle along 8Ivc is approximately proportional to the change in the horizontal prism along its cross-sectional curve, the 8th
It can be regarded as vertical distortion at each cross section in the figure. Horizontal distortion is related to vertical line distortion; if there is no vertical line distortion, the horizontal edge will not be distorted, and the horizontal line will also be distorted where the vertical line is distorted. Therefore, in the distance vision area and the near vision area,
The strain force lattice becomes a normal strain in which it deforms into a square shape, and the intermediate region becomes a skewed wax in which the strain force lattice deforms into a parallelogram shape. This allows me to suppress the value of the distance vision area and near vision chain acid from VC.

In addition, in the intermediate region, by making the method of distortion of the vertical line the same as the law of change in the rate of change in darkness from the distance center of the principal meridian curve to the center of near vision, the principal meridian curve can be distorted. The astigmatism at the top is set to t-zero, and the gratings on the same side are arranged to suppress astigmatism and image distortion as much as possible.

The present invention is a progressive multifocal lens based on such a basic idea, which has been improved in manufacturing and usage.

Characteristics of progressive multifocal lenses that differ from single focus lenses, bifocal lenses, etc. include the following. First, regarding the manufacturing of the lens, since the entire lens is not made from a spherical surface with an inclination of V and has an aspherical shape, it is difficult to form the lens using normal optical or mechanical methods. The management of the foot and the form 5aIf based thereon is difficult. In addition, when wearing glasses, the width of the intermediate clear vision range is narrow, so it is necessary to strictly fit the positional relationship between the left and right lenses and both eyes, taking into account the convergence of the eyes from distance vision to distance vision. be. Figure I@9 shows the movement of the line of sight on the spectacle lens when looking at an object at an intermediate distance from the intermediate clear vision range. As the eye moves from an object in the horizontal distance to an object at hand, the point on the lens through which the line of sight passes is sequentially moved to point a in the figure by the eyeball's convergence.

The trajectory of this visual deviation has an angle of about 101 [from the vertical. - When looking at @ in the sword, distance area, and near area, when looking at the %IC, move your face so that the face is in front of your face, a-a' on the lens.
- and bb' use a lot of neighborhoods.

It is desirable that there be no astigmatism in the vicinity of a-a'+b-b'. (a'-a-b-b'1
1 will be called the visual center. ) For this reason, conventional progressive multifocal lenses create a umbilicus-shaped curve l1i along the visual center @.
lt-, or by making the distance S5 region and the near vision region spherical to create a geometrically symmetrical lens. I was letting it happen. However, if a navel-shaped curve is provided in alignment with the center line of vision, the lens becomes geometrically asymmetrical, requiring dedicated lenses for the left and right lenses. Is this the lens manufacturer's? This is extremely inconvenient as it takes a lot of effort to manage the production process until the glasses are finished. - If the distance vision area and the near vision area are made spherical, the width of the intermediate visual field becomes narrower, and it becomes necessary to adjust the lens's ink to the eye more accurately.

The present invention overcomes the above-mentioned drawbacks and provides a progressive multifocal lens that is easy for users to use, easy for lens manufacturers to manufacture, and easy for eyeglass manufacturers to manufacture.

Hereinafter, the present invention will be explained in detail using Example KJc.

FIG. 10 is a front view of a progressive multifocal lens that is an embodiment of the present invention. This 5jl! In the example, the distance vision center A is located at the geometric center of the lens, and is horizontal to the boundary line C1 between the distance vision area and the intermediate area. Another advantage is that an aspherical area D1 is provided around the center of the near vision area on the boundary line C2 between the near vision area and the distance vision area. To be more specific, the spherical area in the distance area is more than 2.5-degrees from the principal meridian curve, and as the principal meridian curve force collapses in the area D1 outside of that, the horizontal direction is Curvature increases. In addition, 2
The main meridian [1
1,;C1,□ka,bvchlei”F15risr*
4-tslK+-r'ru. In other words, if the cross-sectional curve is directly fired with the principal meridian, it has a circular shape at a distance of 2.5 square meters or more from the principal meridian resistance curve in the distance area, and the radius of curvature of the circular shape is the cross-sectional curve and the principal meridian. Equal to the radius of curvature of the principal meridian curve at the point of intersection of the curves.

In addition, there are also non-circular fall pipes whose radius of curvature decreases as the distance from Tamagosen@@@'tIh increases.

The distortion of the lattice image when viewed through this lens is shown.The broken part in the figure shows the chain acid division in Figure 10.
In the part corresponding to the spherical surface of the distance region, the square lattice becomes a square lattice magnified by an image magnification corresponding to the refractive power there, and in these inertial force regions, the light is strictly focused in the direction shown by the arrows on both sides of the figure. It becomes normal gold with the minimum refractive power. At this time, in the inertial force region of the distance vision area, #/c moves toward the periphery, so that the lattice image is strongly stretched by the horizontal force. , Fig. 13 shows the distribution of astigmatism in tcv, the area surrounded by a broken area in the clear vision area without hatching, and the area in the intermediate S-castle and near vision area] 1. This is the region where the astigmatism is zero. In the far vision area, astigmatism increases approximately in proportion to the way the curvature increases in the front part D1.

Next, the effect of non-invention will be explained.

FIG. 14 shows the beading when the lens of this embodiment is used as eyeglasses. The lens is machined into a bead shape F by tilting it about 10 degrees so that the visual field ia when viewed horizontally is at a position 2 to 3 wg dots from the distance center A on the principal meridian -4 curve. In the figure, the clear vision area and sphere n shown in Figure 13 are shown.
c + A castle is drawn, and the truth is on the right side of the figure.As is clear from this figure, by tilting it by about 10 degrees, the principal meridian curved edge M coincides with the visual center-earth a-b rock described earlier. , use] You can obtain a good intermediate vision.

The effect of the present invention is noticeable in the distance vision center. In other words, the visual center #a' is located in the distance vision area.
-a-A is almost included in a spherical region with a width of 2.5 or more from the principal meridian curve 1s force, and the astigmatism of the visual center is zero. In addition, it is obvious that the normal illumination has a distance of 12 to 15 smm degrees and an inclination of 10 degrees.

The fact that the astigmatism on the central visual layer, which is most frequently used by people who often see distant objects and which is useful for gaze work, is zero, reduces eye fatigue due to long-term use. There's no need to worry about doing it. Furthermore, according to the present invention, there is no need to make the lens asymmetrical in order to eliminate astigmatism on the central visual layer, which is used as a ruler, and the lens can be simply tilted 15 degrees in the opposite direction on the left and right sides of the eye. Since this type of lens can be used as the left and right lenses of eyeglasses, it brings great benefits in terms of manufacturing and management until the end of the eyeglasses.

Furthermore, in the lateral force region of the distance vision region, the curvature in the direction perpendicular to the main meridian 1 is changed as explained above, compared to the case where the distance vision S region is entirely a sphere (2). All songs of the statue in the middle part area! ! Along with 4λ, the width of the intermediate visual field is widened, and the position of the curvature and the main meridian curve is improved! f4Jf is relaxed.

-73, By providing a spherical part in the distance region on the mm plane of the lens, the precision of the refractive surface of the lens during the manufacturing process can be improved.
It is represented by its spherical part and can be easily measured by optical or mechanical power stroke rC.

As explained above, the progressive multifocal lens according to the present invention has
It provides good static and dynamic vision for the user, facilitates the fitting of glasses for eyeglass makers, and provides easy manufacturing and management for lens manufacturers. It is something to give.

[Brief explanation of the drawing]

Figures 1 and 2 = 5 + 4 show the structure of a general progressive multifocal lens, changes in bending refractive power on Tamako Sengan curve, astigmatism distribution,
A diagram explaining all the songs of the lattice image. Figures 5.6.7.8 are diagrams illustrating the tube of the present invention. Figure 9 shows the movement of the line of sight on the glasses. @10.11. Figure 12.14S shows the uninvented one-dimensional structure, Figure 10 shows the front view of the refractive surface of the lens, Figure 11 shows the curved refractive index distribution of the principal meridian-curve soil, and Figure 12.15 shows the curved refractive index distribution. Distortion and astigmatism of the grating image are shown. Fig. 14 is a diagram illustrating the effect of the present invention in removing the balls from the eye. Two fists M...Thousand balls of the eye - Curve A...Distance center B ... Center for near vision C1... Boundary curve between distance vision s'm castle and intermediate area 1 - C2.
・Below the boundary curve between the intermediate vA region and the near chain acid Figure 9 Figure 10 Figure 11 Inset Figure 13

Claims (1)

[Claims] On the principal meridian curve, the curvature changes according to a predetermined law from the distance center to the near center on the principal meridian curve. ] Due to the curved leg C1 that intersects with the kiojigo mt song - and the song dc2 that intersects with the fiJB kiojigowao kokuwao at the near center,
Refractive surface f of the lens: divided into a distance region, an intermediate region, a near vision region, and a front region, and includes the main meridian curve Iilwo.
For each arbitrary cross-sectional curved edge that is the intersection of an arbitrary plane parallel to The angle formed with the plane containing the distance vision area and the near vision area is one foot each, and the curvature between the center of distance vision and the center of near vision on the Oji Goan curve in the intermediate region. In a progressive multifocal lens that changes according to the same law as the law of change of I
I] Hi in the meridian curve # @ in the distance area!
The curvature that is the same as the center curvature for distance vision is 1 for near vision sv! A
In the area, the curved edge of the cross section that contains the same curvature as the curvature of the center of near vision, and is the center of the plane that is perpendicular to the meridian curve and the refractive surface of the lens, is the distance vision area of 1st century. At @jijiri - a distance of at least 2.5- from the curve 1. It has a circular shape with a curvature equal to the curvature of the principal meridian curve in the distance region, and otherwise! 1] Kijigo li!
A progressive multifocal lens that unfortunately has a non-circular shadow shape whose curvature increases as it moves away from iI.