JP2550404B2 - Multifocal lens with progressive focus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multifocal lens with a combination of a conventional multifocal lens and a progressive focus lens, which is novel between the two, and which is clearly divided and has progressive focal spots.

BACKGROUND ART In middle-aged people, the accommodation power of the crystalline lens of the eyeball weakens, and it becomes difficult for a person who can see far objects well to focus sharply to see nearby objects. This is an unavoidable phenomenon due to human aging, and this is called presbyopia.
Traditionally, the treatment for presbyopia is to use a multifocal lens with two or more different visual field parts depending on the viewing distance. The auxiliary visual field of these different visual fields is called Kodama, and development efforts have been continued for many years to construct a monofocal region of moderate addition power with little astigmatism.

A multifocal lens clearly divides the field of view corresponding to different viewing distances into a distant field of view pedestal and a near field of view small sphere, and shares the functions.
It has a history of 230 years, and there are various ways to add small balls, but they are all composed of several single focal zones that give an appropriate position, width and addition power, and reduce their aberrations and spherical accuracy. Development efforts have been made to improve. Each belongs to a technology having a different purpose from the present invention.

On the other hand, there is a progressive focus lens, and the first feature and development purpose of it are that there is no boundary between the far field and the near field, and it does not look like a multifocal lens in appearance.
This is taken up in commercial activities as the first commercial value. The second feature is that there is no jumping due to abrupt image changes between the far field and the near field and between the near field and its side field, as compared to the multifocal lens with a single-focus small lens. There are points. However, the drawback of the progressive focus lens is that it is only a part of the whole field lens with little aberration, and if the lens is designed with an emphasis on the optical characteristics in the vicinity of the progressive curve, it will inevitably be located on both sides of it as the distance from the progressive curve increases. Astigmatism and distortion that increase in size are generated, and in order to obtain a wide effective field of view, it is necessary to measure the dispersion of the aberration throughout the lens. Japanese Patent Laid-Open Publication Nos. Sho 62-150215 and Sho 62-183424 disclose, as a part of this progressive-focus lens, a small ball portion, but each of them is intended to improve the above-mentioned peripheral visual field of the progressive-focus lens. , Belongs to a technology having a different purpose from the present invention. Progressive focus lenses have a history of about 80 years.

On the other hand, there is a multifocal lens that uses the technology of partially increasing the refractive index of the material, but because of its narrow focal range and monotonous progressive distribution, it is possible to create an ideal optical design. It is difficult to put into practical use because it has no size. These belong to the technology having means different from the present invention, and neither of them provides a progressive focal area in the small ball portion. Next, the prior art JP-A-62-183424 and the present invention described above will be compared and described. 1. [Difference of Object] The prior art is
The manufacturing method disclosed or suggested therein also targets plastic lenses, and in the present invention, general lenses including inorganic glass and bonded lenses are also targeted. 2. [Advantage] The prior art is to give a deformation of the progressive portion to a mold that is formed with small balls in advance, and it is not possible to provide the correct progressive portion only for the small balls. Since it is a lens, astigmatism and distortion aberration that accompanies progressive power remain in the pedestal, and in the present invention, since the entire pedestal is a single end point region with no progressive portion, there is naturally no such aberration. Furthermore, the present invention allows the progressive distribution state to be freely designed only for small balls, and even a rapid progressive design only affects the step of the boundary line of the small balls and has no effect on the pedestal. There is a nature. 3. [Uniqueness] In the prior art, in order to form the shape of a small lens, a difference in refractive power of the upper part of the small lens of at least 0.5 diopter is inevitably required, and a step of the image occurs at the boundary, but according to the present invention For example, since the shape of the small ball can be set from the beginning, the refractive power of the upper part of the small ball can be made the same as the refractive power of the pedestal, and there is the uniqueness that it can progress without steps. 4. [Purpose of difference] The prior art has the purpose of reducing the amount of progressive diopters by adding small balls to reduce lateral astigmatism and distortion associated with progressive power. On the contrary, the present invention, on the contrary, has the object of achieving a strong progressive power quantity by means of a progressive focus lens. Five.
[Advance, Difficulty] According to the manufacturing method disclosed or suggested in the prior art, it is a feature of the present invention to provide a progressive portion or a prism without being restricted to only the small balls. Is not possible, and is possible only by the inventive and sophisticated manufacturing method of the present invention described below.

In the present invention, the idea is changed away from the preconceived concept, the pedestal part is left as a single focal area, and the small size of the small ball is used conversely, and the progressive focus is applied to it. The optical capability is significantly expanded by applying the function of.

DISCLOSURE OF THE INVENTION (a, Utilization for a portion having less astigmatism in the progressive focal region) The main purpose of the present invention is to obtain the smallest progressive curve of the astigmatism that necessarily occurs in the progressive focal region. Only the near part is used within the small ball and the harmful part is removed. Since the progressive focal region progresses along one progressive curve, a large astigmatism is generated as an optical characteristic as it goes away from this progressive curve to the side. Removing the optically harmful portion significantly enhances the optical characteristics of the spectacles, and is a serious problem even if it adds some capability.

(B, Enlarge the field of view without distortion or shake to the whole area) Distortion of the image of the lateral field of view, which inevitably occurs with the progressive focal range, and when the viewpoint moves laterally, it is felt as waviness or shaking. However, it may cause nausea until the user becomes accustomed to this, which may cause nausea.

Another object of the present invention is to use only a portion near a progressive curve and having a small defect that does not affect the field of view for a small ball, and for a lateral visual field where a sway is felt, the outside of the small ball is detected. It is to obtain a stable visual field free from image distortion and shaking, which a conventional multifocal lens has, by using the single focal area of the table.

(C, Designing the progressive focal area ideally and freely) Smoothness is required by avoiding abrupt image changes when shifting from a single focal area to a progressive focal area, requiring a large progressive power with a short progressive distance. In order to obtain it, it is necessary to design the degree of progression by freely strengthening or weakening without being restricted by the side. In addition, in order to reduce astigmatism, distortion, etc. to improve the optical performance, it is designed in a complicated aspherical surface by progressively progressing in directions other than the progressive curve. , It is necessary to remove the inconvenient part that inevitably occurs on the extension surface and becomes larger as it goes away from the progressive curve to the side, and another object of the present invention is to cut off the continuation at the border line of the small ball and use it. This is to limit the progressive focal plane to a portion close to a progressive curve with little aberration, and to freely design an ideal surface inside the small ball.

(D, to obtain a visual field of continuous visual distance in a stepless manner) Another purpose is to provide a progressive focal area between a long-distance viewpoint and a short-distance viewpoint in a progressive-focus lens inside a known small lens. This is to make the ability of the small ball's field of view remarkably leap by making it possible to see clearly in a wide range of viewing distances, which can not be obtained conventionally.

(E, Minimize the jump at the top of the bead) Another purpose is to minimize the jump at the top of the bead. In normal Kodama, when the line of sight is shifted from long-distance vision to near-distance vision to Kodama, the image suddenly rises upward at the boundary line and jumps, which is the base when passing the boundary line. This is because the prism on the lower side is added, and the larger the addition power, the larger the center of the small lens becomes farther from the center of the long-distance optical optics, resulting in a blind spot that cannot be partially seen on the boundary line. To remove this, it is necessary to add a prism above the base of the small ball.

(F, the prisms in the vertical direction for short-distance vision are made to strike each other in the horizontal direction) Ordinary spectacles are adjusted with reference to the far-distance optical center of the left and right lenses. Is common, and as a result of the multifocal lens having a near vision monofocal region at a position distant from the far vision optical center,
The prism powers in the vertical direction for near vision for the left and right eyes differ, and the greater this difference, the more likely it is that fatigue will occur, and if the limit of image fusion is exceeded, double images will occur and diplopia will occur. ) Will occur.
In order to remove this difference, one lens is slab-off processed and left and right flat, but it becomes expensive because a special order is required due to a refined technology, and only one side has a slab-off processing line on the side, so it is external in appearance. Is also not preferable. Another object of the present invention is to add prisms only to small pieces in advance so that it can be applied to all kinds of eyeglass prescriptions, and make a series of stages as prism small pieces semi-finished products, and the most suitable one can be easily selected and used. To do so.

(G, lightening the weight of the convex lens) In the convex lens, the prism required for the progression of the conventional progressive multifocal lens and the prism required for the slab-off process are the whole lens to add the prism to the full width of the lens. The thickness must be increased and the weight will increase. Another object of the present invention is to significantly reduce the weight of the convex lens by limiting the increase in the thickness of the prism to only the small balls used for near vision.

(H, the synthetic optical center is also set to the single-focal range for short-distance vision) The synthetic optical center is the point where the prism of the small lens and the prism of the pedestal are combined at a certain position to become 0, which is correct. You can see things in the direction.
With various conventional multifocal lenses, when the optical center is set in the long-distance single-focus region, the composite optical center can be set in the short-distance single-focus region extremely rarely. Another object of the present invention is to easily select the most suitable prescription from among the prismatic small balls made by the stepwise series, and to bring out the synthetic optical center even in the short distance single focal range. It is in.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of the first embodiment, FIG. 2 is a perspective view of only the small balls of the first embodiment, and FIG. 3 is a projection of the small balls of the first embodiment.
FIG. 4 is a cross-sectional view illustrating the minimum center of curvature of jumping, FIG. 4 is a cross-sectional view illustrating the center of curvature in which the small balls of Example 1 are projected, and FIG. 5 is a front view of Example 2, FIG. 6 is a perspective view of only the small ball of the second embodiment, FIG. 7 is a sectional view illustrating the small ball of the second embodiment in a projecting manner, and explaining the center of curvature of the minimum jump, and FIG. 8 is the small ball of the second embodiment. A cross-sectional view for explaining the convexity and the center of curvature of the smallest ball difference, FIG. 9 is an explanatory view for showing a logarithmic spiral as a progressive curve, and FIG. 10 is an explanatory view of a small ball embedding member for a small ball mother die of Example 1, FIG. 11 is a cross-sectional view of a plastic casting mother die of Example 1, FIG. 12 is an explanatory view of a fusing bead embedding member for fusion spouts of Example 1, and FIG. 13 is embedding the flake of Example 1. FIG.

1 ... baseball, 2 ... small ball, F ... distance vision single focal range, 1
...... Medium-distance vision single focal area, P ... Progressive focal area, M ... Boundary surface, N ... Near-distance vision single focal area, S ... Progressive curve Best mode for carrying out the invention Refracting power for small balls There is a method of partially changing the refractive power of the material as a method of giving. However, in the present invention, a method of changing the surface refractive power is used to adjust the delicate refractive power.

Embodiment 1 will be described with reference to FIGS. 1 and 2.
The pedestal 1 is a single focal range F for long-distance vision including the optical center 3 for long-distance vision. The lower part of the small ball 2 having a clearly demarcated boundary line has the single-focal area N as the refracting power used for near vision,
There is a boundary line outer diameter center 4 in the near vision single focal point region. The upper part of the small ball is along the direction from the long-distance single-focus area to the short-distance single-focal area, along the progressive curve S from the upper edge center 5 to the upper center 7 of the short-distance single-focal area N. A progressive-power curved surface area P with a small astigmatism that progressively progresses from the surface refractive power in the long-distance single focal area to the short-distance single focal area.

In order to form the region continuously while avoiding abrupt changes in the surface refractive power, the smooth boundary surface M illustrated by the dotted line is configured to widen in the lateral direction.

As shown in Fig. 1, it is better to wear the Kodama by inclining it by an angle θ from the vertical direction, usually about 10 °, in order to direct it in the direction of movement of the line of sight from long-distance vision to near-distance vision. In order not to hinder the movement of the small balls and to make the small balls the same shape on the left and right, the upper boundary of the small balls should be a gentle arc perpendicular to the direction of progression, and the radius of curvature must be larger than the diameter of the small balls. An arc with a 45 mm radius is the best for a 30 mm small ball, and the radius of curvature is 1.5 times the small ball diameter.

As shown in FIGS. 1 and 2, as an optical design considering only the movement of the line of sight in the long-distance single-focal range F and the short-distance single-focal range N, the upper boundary line of the small ball is a straight line perpendicular to the progressive curve S. However, it is better to make this a gentle arc when worn, so the optical design of the upper end of the small ball 2 should be the same surface refractive power along the gentle arc from the progressive curve to the side. To do.

The border line 12 beside the bead is graceful by using an arc having the same curvature, but is not limited thereto. The contact point between the arc of the upper boundary 11 and the arc of the horizontal boundary 12 is a shoulder boundary 13 connecting Rs without corners for ease of manufacturing the small balls.

A second embodiment will be described with reference to FIGS. 5 and 6.
The pedestal 1 is a single focal range F for long-distance vision including the optical center 3 for long-distance vision. The upper part of the clearly separated small balls 2 is made into a single focal range I of the refractive power for medium-distance vision which is often needed in the life of an individual, and a stable visual field is supplied there. The lower part of the small ball is defined as a single-focus area N having a refractive power for short-distance viewing, and a boundary line outer diameter center 4 of the short-distance single-focus area exists therein. In the meantime, along a progressive curve S from the lower end center 6 of the medium-distance single-focus area I to the upper-end center 7 of the short-distance single-focal area N, from the surface refractive power of the medium-distance single-focal area to the short-distance single focus. A progressive-power curved surface region P having little astigmatism that progressively reaches the surface refractive power of the region is set.

In order to form the three areas continuously while avoiding a sudden change in the surface refractive power, the smooth boundary surface M illustrated by the dotted line is configured to widen toward the side.

In order to direct the line of sight from the long-distance view to the near-distance view, the small ball is angle θ from the vertical direction, as shown in FIG.
Normally, it is better to wear it by tilting it by about 10 °. At that time, in order not to interfere with the horizontal field of view for long-distance and medium-distance vision, it is better to make the upper boundary line of the small ball a horizontal gentle arc, its curvature The radius must be larger than the diameter of the small ball, the diameter is 30
For small balls of 45 mm, an arc with a radius of 45 mm is the best and has a radius of curvature 15 times the diameter of small balls.

The border line 12 beside the small ball is graceful by using a straight line parallel to the progressive direction, but is not limited thereto. The boundary line 11 of the upper part of the small ball and the straight line of the horizontal boundary line 12 are connected to each other by a shoulder boundary line 13 which is connected by a rounded corner R for ease of manufacturing the small ball. It is better to cut the lower part of the bead instead of the semi-circle 9 shown by the dotted line so that it is cut with a gentle arc in the horizontal direction like the upper part. This will reduce the vertical height of the bead and the effect of reducing the thickness of the prism bead. is there. In this embodiment, when a stable monofocal region with an intermediate distance is required to keep a close eye on one part of the occupation, or when the addition power is large, the power is changed by a slight movement of the viewpoint to avoid the unstable focus. It is particularly useful to limit this from the intermediate distance to the short distance so that a good continuous visual field can be obtained without difficulty.

Example 3 in which the entire small ball is a progressive focal range (not shown) will be described regardless of the sizes of the short-distance single-focus area N and the intermediate-distance visual focus area 1 described in the first and second embodiments. The invention does not limit the size in particular, and if it is made extremely small, the entire area of the small lens becomes the progressive focal area P. This progressive focal small lens is produced by applying the progressive focus lens design method and manufacturing method of the prior art. In addition to the advantage that only the part close to the progressive curve can be used due to its limited size, the part where the line of sight is frequently used around the progressive curve is designed as a focus with less aberration. As in the first and second embodiments, the conventional technique has the advantage that it can be ideally designed without being restricted by a distorted surface that is generated on extension, suffers from processing, and is distorted. This embodiment is particularly useful for a case where the line of sight is constantly moving from a long distance to a short distance or an intermediate distance to a short distance rather than continuing to gaze at one portion, such as driving or shopping.

In the present invention, an embodiment for minimizing jumping at the upper edge of the small ball will be described. In FIG. 3, a direction connecting the center of curvature f of the distance power of the pedestal and the upper edge center point 5 of the small lens, and the center of curvature 5 of the upper edge center 5 of the small ball and the distance power of the small distance f of the small lens. When a prism is provided on the small lens so that the direction connecting ′ is the same (the angle β described later is set to 0), the image jump at the upper edge of the small lens is minimized.

Similarly, in FIG. 7, the direction connecting the center f of curvature of the distance power of the pedestal and the center point 5 of the small edge of the small lens, and the center point 5 of the upper edge of the small ball and the medium power of the small distance When a prism is provided on the small lens so that the direction connecting the centers of curvature i coincides (the angle β described later is set to 0), the image jump at the upper edge of the small lens is minimized.

An example of minimizing the step difference of the small balls in the present invention will be described. It is better for the appearance of the eyeglasses to have the smallest level difference between the balls. In FIG. 2, when the step of the boundary line 10 in the near vision single focus region becomes 0, the outer center 4 of the near vision single focus region and the long-distance refractive power of the pedestal in FIG. 4 and FIG. The center of curvature n of the short-distance refracting power of the small ball is on the straight line connecting the centers of curvature f.

At this time, a direction connecting the center point 5 of the small edge of the small ball and the curvature center f of the long-distance refracting power of the base ball and a direction of connecting the center point 5 of the upper edge of the small ball and the curvature center f'of the long-distance refractive power of the small ball. Sandwiches the angle β, and the jump occurs at the upper boundary of the small ball by this amount.

Similarly, in FIG. 8, a direction connecting the center point 5 of the small edge of the small lens and the curvature center f of the long-distance refracting power of the base ball and a direction connecting the center point 5 of the upper edge of the small lens and the center i of the intermediate distance curvature are angled. A pinch of β causes the jump at the upper boundary of the small ball.

An example will be described in which the present invention is carried out with the left and right prisms at a short-distance viewpoint in parallel. The upper and lower prisms are attached to the small balls of the present invention in advance, and the small balls are manufactured in series at intervals of, for example, 0.5Δ (prism diopter).

To calculate the left and right short-distance viewpoint prism differences from the spectacle prescription, P ... left and right short-distance viewpoint prism refractive power difference (Δ) D ... left and right long-distance viewpoint refractive power difference (D),
d ... Distance from the long-distance viewpoint to the short-distance viewpoint (mm), which is obtained from the following formula: P = D · d / 10 For example, prescriptions for glasses R.S + 0.75, L.S + 1.50, When the add power is 1.50 on the left and right, and the distance from the long-distance viewpoint to the short-distance viewpoint is d = 18, the difference in vertex refractive power between the left and right long-distance viewpoints is D = 0.
75, Prism difference P = 0.75 × 18/10 = 1.35 △, so there is a + difference above the base on the left lens, and on the right lens of the opponent to be paired there, the prism small ball 1.0 △ base above or 1.5 △ base You can also add a non-jumping effect by choosing the upper part or choosing a small ball with a minimum jump of just 1.4 △ above the base and making it strike.

Other examples include eyeglass prescription RS-0.50, LS-1.0.
0, add power left and right 1.50, distance d = 18 from the long-distance viewpoint to the short-distance viewpoint, the difference in the apex refractive power D = 0.50, the prism difference P = 0.50 x 18/10 = 0.9 △ , -There is a + difference below the base in the left lens, so if you select 1.0 Δ above the prism small lens for this left lens and strike a balance to cancel this difference, the effect of reducing jumping may be added. In the case of Examples 2 and 3, the prism equilibrium is calculated in the same manner at the position at the center of the small lens.

It is very costly to make the lens of the present invention shown in FIGS. 1 to 8 from a glass material by polishing the small balls integrally by polishing, and it is possible to reproduce a large amount by molding using a plastic material. Therefore, this embodiment will be described.

FIG. 11 shows an example of a mother die 30 for casting a plastic lens. Normally, a multifocal lens has a small ball on the convex surface, but in order to mold this, it is necessary to make the multifocal surface of the progressive small ball of the present invention on the concave surface of the mother die, which can be realized for the first time by a completely new manufacturing method. Become. As shown in FIG. 10, a small bead embedding member with a small thickness is formed in advance by forming a recess 22 having a bead contour in a small bead contour member 21 and embedding an etching glass bead 23 in it.
A heat-resistant molding tool 28 that is fused with an optical spherical surface 26 together with 25 and made into a precise three-dimensional curved surface, and a known method for softening and deforming the glass on it is a progressive refraction surface on both fusion surfaces. To create. It is again shaped and polished into a small ball shape, and is again fused to the mother die material 30 on the fused spherical surface 32 shown by the two-dot chain line in FIG. Note that the small contour member 21
The small ball embedding member 25 and the matrix 20 are of the same quality, and after fusion bonding, they become the same body and the fusion bonding surface disappears. Then, after the far-distance refracting surface is formed and polished on the entire surface, the small bead portion made of the etching glass is removed by etching to form the concave portion which becomes the progressive small bead of the present invention. At this time, in order to form the above-mentioned prism small balls, the high refractive index glass small balls can be set at the fusion-bonded spherical surface position which gives a correct prism. A plastic lens in which small balls are integrally projected is cast using this mother die by a conventionally known method. In addition to this, injection molding or plastic molding can be performed.

An example will be described in which the present invention is carried out as a conventional fusion-bonded bead shape. This can only be achieved by a completely new manufacturing method. As shown in Fig. 12, a small, small-sized contour member is prepared in advance.
High refractive index glass beads 24 made by forming a recess 22 with the outline of a ball in 21
, A heat-resistant molding tool made into a precise three-dimensional curved surface by fusing with a thin ball embedding member 25 and fusion with an optical spherical surface 26.
28 is used to create a progressive refraction surface on both fusion surfaces by a known method in which the glass is softened and deformed. It is again shaped and polished into small balls, and is again fused to the base material on the fused spherical surface 32 shown by the chain double-dashed line in FIG. 13 by a known method of fusing small balls. Note that the small bead contour member 21, the small bead embedding member 25, and the base material are of the same quality, and after fusion, they become a body and the fusion surface disappears. Next, the entire surface is molded and polished into a long-distance refracting surface to produce the fused beads of the present invention. At this time, in order to use the above-mentioned prism small balls, the high refractive index glass small balls are set at the fusion-bonded spherical surface position which gives a correct prism. Since the progressive refracting surface and its prism are created and constructed inside the lens in this way, the outer surface is smooth and free from dirt, which is useful and good in appearance.

An example of carrying out the present invention as an adhesive ball will be described. Second
It is possible to form a small ball as shown in FIG. 6 and FIG. 6 separately from an optically transparent material, and to bond it to an pedestal with an optical adhesive to form a small ball. At this time, if a slightly flexible material such as plastic is used, it can be adhered to a spherical surface or toric surface having a slightly different curvature of a single-focus lens or to eyeglasses already in use. . This is a novel one that has never been seen before, is economical, and can be applied as a conventional multifocal lens. It is very useful when the product of the present invention is used on a trial basis at a low cost and the effect is experienced.

The feature of using a logarithmic spiral in the progressive curve S of the present invention will be described. Any progression curve may be used without limitation. However, as a result of various studies, the use of a logarithmic helix is compatible with the degree of proportional progression and the rate of increase in refractive power with the movement of the line of sight from long-distance to short-distance vision. Even if the logarithmic spiral of the necessary progressive force is selected from the length of the progressive focal zone and the radii of curvature before and after the progressive, the prism angle due to the progressive is obtained and the angle β that results in the jumping of the image described above.
It has been found that it is convenient for calculating.

The In FIG. 9, the progressive curve ranging from 5 to 7, the logarithmic spiral to pole 0, the formula ^r = r ₀ e 0cota length of the progressive curve | radius of curvature R _f short distance far vision refractive surface Radius of curvature of visual refraction surface R _n Equal angle of logarithmic helix α ＝ tan ^-1 | / R _f- R _n Radial of logarithmic helix from 0 to 5 r _f ＝ R _f sin α Motion of logarithmic helix from 0 to 7 Diameter r _n = R _n sin α Radial angle of logarithm (Rad) θ = log k · R _f / R _n Constant of logarithmic helix K = e ^{2ncota Using the} above equation, short-distance single focus of Example 1 5 to f for the case where the diameter of the small ball is 30 mm and the length of the progressive curve is 12 mm
The angle β between the direction and the 5'to the f'direction can be calculated. For example, INDUSTRIAL APPLICABILITY The present invention is useful with the following effects.

a, The progressive focal range is limited to the inside of the small lens, and only the part close to the progressive curve with less astigmatism is used, and it has the effect of removing harmful parts, which is especially useful for eyeglasses of people with large addition power. .

b, It has the effect of obtaining a stable wide field of view without distortion such as upright tilt or horizontal inclination of the image in the side view and the defect that it feels as shaking when the viewpoint moves sideways, especially to the left and right. It is useful for eyeglasses of people who move their eyes a lot or who see the uprightness or inclination of an object in their visual field.

c, It has the effect of freely designing the progressive focal area, such as obtaining a large progressive power with a short progressive distance and avoiding sudden image changes when moving from the single focal area to the progressive focal area to obtain smoothness. .

d, It has the effect of steplessly providing a clear visual field corresponding to a wide viewing distance in a small ball, and is particularly useful for eyeglasses of a person with a large addition power.

e, It has the effect of making the upper part of the small ball non-jumping, and is particularly useful for eyeglasses of a person who frequently moves his or her line of sight between a long distance and a short distance.

f, Among the prismatic small balls that are pre-staged as semi-finished products, the one that is most suitable for the prescription can be easily selected, and it is inexpensive regardless of special orders such as slab-off processing. It is effective for flattening the left and right sides, and is especially useful for human eyeglasses with a large difference in power between the right and left eyes.g, In the concave lens, the thickness of the prism required for progressive or slab-off processing is reduced. It has an effect of remarkably reducing the weight, and is particularly useful for eyeglasses of a person whose left and right eyes have a large difference in power.

h, It is easy to select the most suitable for prescription from the prismatic small balls that have been serialized as a semi-finished product in advance, and there is an effect to bring out the synthetic optical center even in the short-distance vision single focal range, especially near-distance It is useful for eyeglasses when the monofocal region is used for a long time or when fingertips are used.

As described in detail above, not only the advantage of simply providing a progressive focus portion on the small lens of the multifocal lens, but also a large number of synergistic effects are produced, and the usage pattern of the multifocal lens wearer,
It is possible to easily and freely select and supply a lens that suits the optical characteristics, and it is useful to obtain unprecedented comfort during wearing.

Claims (12)

(57) [Claims] 1. A multifocal lens in which a pedestal is a long-distance monofocal region (F), and a lenticular region for imparting additional refracting power, which is clearly divided in the pedestal, is provided. The region has at least one stable monofocal region (N) and a progressive point region (P) with less astigmatism, and each focal region has a continuous surface shape in order to avoid abrupt image change. A multifocal lens with a progressive focal point tiny ball. 2. The single focal area (N) of the small lens area is located in the lower portion of the small lens area as a short-distance single focal area, and the progressive focal area (P) is for long-distance viewing. A multifocal lens, which is located at an upper portion in the small lens region as a focal region for progressively increasing from a surface refractive power to a surface vision power for short-distance vision. 3. The monofocal region (I) having a surface refractive power for medium-distance vision is located at an upper part in the small lens region according to claim 1,
A single focal range (N) having a near-distance surface refracting power is located in the lower part of the small lens area, and the progressive focal range (P) is from a medium-distance surface refracting power to a near-distance surface refracting power. A multifocal lens, characterized in that it is located between the two monofocal regions as a progressive focal region. 4. The small ball area according to claim 2 or 3,
By providing a prism force of an amount sufficient to match the focal direction of the upper end portion of the small lens area and the focal direction of the adjacent pedestal, when the line of sight moves from a long-distance viewpoint to a short-distance viewpoint, A multifocal lens characterized in that the jump of an image at the boundary of the small lens area is suppressed to a minimum. 5. The method according to claim 2 or 3, wherein the thickness of the near vision single focal area (N) of the small lens area is minimized.
A multifocal lens, characterized in that the boundary line of the small ball region is made unobtrusive. 6. The plurality of additional prism forces selected for the purpose of minimizing the difference between the left and right prism forces in short-distance vision according to the spectacle prescription according to claim 2 or 3, and the selection is performed. A multifocal lens, wherein the generated additional prism force is added to the small lens area. 7. The multifocal lens according to claim 2 or 3, wherein when the base ball and the small lens area are integrally molded using an optically transparent material, the small lens area is provided in a convex shape. . 8. The ball-shaped region according to claim 2 or 3, wherein the small ball region made of an optically transparent material having a refractive power higher than that of the base ball is embedded in the base ball, and the base ball and the small ball region are separated from each other. A multifocal lens, characterized in that a progressive-focus refracting surface is formed on the fusion-bonding surface of. 9. The method according to claim 2 or 3, wherein the small ball region formed as a single body using the optically transparent material is bonded to the base ball so as to have a convex shape. Multifocal lens. 10. The multifocal lens according to claim 2 or 3, wherein a logarithmic spiral is used as the progressive curve (S). 11. The pedestal is a long-distance vision single focal range (F),
A multifocal lens which is clearly divided in the pedestal and which is provided with a small lens area for giving an addition refractive power, wherein an upper boundary line of the small lens area is an arc having a radius of curvature larger than a diameter of the small lens area. Yes, the single focal area (N) of the small lens area is located in the lower portion in the small lens area as a short-distance single focal area, and the progressive focal area (P) is for long-distance viewing due to surface refractive power for long-distance viewing. It is characterized in that it is located at the upper part in the small lens area as a focal area with little astigmatism that progresses to surface refracting power, and each focal area exhibits a continuous surface shape in order to avoid sudden image changes. Multifocal lens with progressive focus small balls. 12. The pedestal is a long-distance vision single focal range (F),
A multifocal lens which is clearly divided in the pedestal and which is provided with a small lens area for giving an addition refractive power, wherein an upper boundary line of the small lens area is an arc having a radius of curvature larger than a diameter of the small lens area. Yes, the single focal range (I) having surface refractive power for medium-distance viewing is located in the upper part of the small lens area, and the single focal area (N) of the small lens area is a short-distance single focal area in the small lens area. An intermediate position between the two focal areas within the small lens area as a focal area with a small astigmatism which is located at the lower portion and in which the progressive focal area (P) progresses from the intermediate refractive surface power to the near visual refractive power. A multifocal lens with a progressive focus small lens, which is located in a section, and each of which has a continuous surface shape in order to avoid a rapid image change.