JPS5862618A - Multifocus lens and its production - Google Patents

Abstract

PURPOSE:To produce a progressive multifocus lens where the visual field of the part for near is wide and the astigmatism of progressive sides is reduced compratively, by combining a mold having a curved surface of the part for near distant use and a mold having the other base curved surfaces. CONSTITUTION:A part L for far distant use which has an opening angle theta1 of 120-160 deg. is formed in the part upper than a center progressive part P, and a part N for near distant use which has an opening angle of about 100 deg. is formed in the part lower than this part P. A progressive side Ps which is formed to a shape like a frequency distribution curve is formed in both sides of the upper part for far distant use and the lower part for near distant use along a longitudinal principal meridian I-I', and a gentle astigmatism is performed in this progressive side Ps. In respect to the production of this multifocus lens, a refractory mold 16 where a mold 18 having the curved face of the part for near distant use and a mold 17 having the other base curved face are combined is used, and a glass material 1 is placed on this mold 16 so that longitudinal principal meridians of the mold and the glass material are matched to each other, and the glass material 1 is heated and molded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multifocal lens and a method for manufacturing the same, and more particularly to a progressive multifocal lens for presbyopia.

Progressive multifocal lenses are currently attracting attention as a so-called borderless bifocal lens for spectacles.

The applicant has been specialized in manufacturing bifocal lenses for many years, but since the cumulative and progressive lenses currently on the market have the following drawbacks, we have conducted extensive research. As a result, the present invention has been completed.

This progressive multifocal lens is characterized by its widely recognized astigmatism, and the ones currently on the market can be broadly classified into the following two types of control systems.

Figures 10 and 11 show conventional examples of progressive multifocal lenses, and the radius of the sphere is the equivalent spherical value at the center of the area.
A line passing through the center indicates astigmatism (astigmatism), the length is the amount of astigmatism, and the t direction indicates the Yayoi radial direction.

In Figure 10) is the 1-port part, ((1) is the near part, (to)
is the progressive part, and ■ is the progressive side, which is a lens that widens the astigmatism of the progressive side over a wide range. As a result, astigmatism will not become stronger in some areas, but the disadvantage of this type of lens is that it is not possible to obtain a stable and wide field of view in the near vision (E) and continuous vision (A) areas. .

FIG. 11 shows another conventional example, in which the barb is the distance part, (A is the near part, the barb is the progressive part, and A is the progressive side.

The upper half of the lens is made up of a distance part which is in good condition, and all of the astigmatism on the progressive side (branch) is concentrated on the left and right sides of the near part (■'). Therefore, the distance viewing section and the near viewing section can provide a clear and wide field of vision. However, the drawback is that it is difficult to use because the astigmatism changes drastically. Therefore, it has been desired to develop a progressive multifocal lens that combines the features of FIGS. 10 and 11.

On the other hand, this type of progressive multifocal lens began in 1909, and in 1949, Lunette of 7 Lancers commercialized it under the product name Varilux, and in 1967, Perthio of France and Rodens of Germany. It was launched by Dock Company. □However, the basic patent has already expired, and the current state of affairs is that the technical know-how is facing difficulties.

However, as prior art, the following technology has been disclosed. JP-A-54-+04851, JP-A-54-10
A series of publications such as JP-A No. 7747, JP-A No. 54-126052, and JP-A No. 54-136350 discloses that the upper and lower ends of the progressive portion interposed in the middle along the main meridian that corresponds to the longitudinal direction of the center Furthermore, JP-A-52-143595 is related to a cutting method and is not directly related to progressive multifocal lenses.Furthermore, JP-A-54-104854 The publication relates to a multifocal lens in which an additional lens for near vision is fused to a main lens for fast vision.

Further, there are two types of manufacturing methods for progressive multifocal lenses: grinding methods and heat molding methods. However, when compared in terms of the simplicity of the working process, the latter molding method is superior. Therefore, as a prior art based on the latter processing method,
There is Japanese Patent Publication No. 53-653.9. However, in general, molds made from refractory materials have only been disclosed in the past as a technology that consists of a single piece, and it is not easy to curve the mold, resulting in poor precision and the possibility of having different molds depending on the power. The problem was that it required a huge amount.

This Japanese Patent Publication No. 53-6559 has a structure related to a lens, and specifically, a surface whose curvature changes gradually encompasses a vertical meridian formed by a single line. , the above-mentioned surface of gradual curvature is constructed by one small rotating cylinder formed at the height of each point of the central meridian. The radius of curvature is configured to be equal to the radius of curvature of the central meridian at the point that serves as a support for the cylindrical surface, and the central axis of the cylinder connects the center of curvature of the chain point to the support point. This relates to a lens that is configured to be perpendicular to the curved line. Therefore, from the viewpoint of a manufacturing method, it cannot be said that this invention discloses any new technology.

In view of the above-mentioned circumstances, the present invention provides a progressive multifocal lens which has a wide field of view in the near field and has relatively small astigmatism on the progressive side. In addition, the present invention aims to provide a manufacturing method that incorporates an unprecedented and innovative molding process in which a mold having a curved surface for the near vision portion is combined with a mold having another pace curved surface as a method for manufacturing lenses. be.

In the present invention, claims 1 and 3 are filed in a consolidated application pursuant to Article 38 of the Patent Law. In other words, it is a progressive multifocal lens that has a wide field of view in the near vision area and relatively small astigmatism on the progressive side. In addition, the distance curved type can be fitted into the bottomed circular hole drilled in the paced curved type.
Of course, the manufacturing method that includes the steps of using a combined refractory mold, placing a spherical glass material on the core mold, and heating and molding it in a heating furnace is applicable not only to the multifocal lens of the present invention, but also to Although other methods can be expected, the scope of claim 3 is described as a method for manufacturing only the product described in claim 1.

Mainly, the C) child line referred to in the present invention is the 1=■' line in each figure,
The center position of the distance portion, the progressive portion, etc. is set along the center line of the lens along the longitudinal direction. In addition, the multifocal lens of the present invention is made of glass and has a smooth one-piece spherical surface, and the distance portion provided above the longitudinal principal meridian has no power for viewing distant objects. For example, the near vision part provided below the longitudinal principal meridian consists of a near vision lens that allows people with presbyopia to see nearby objects, but the curvature of its high refraction is In other words, precision is provided on the back side of the lens.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a multi-focus lens and a method for manufacturing the same according to the present invention will be described below with reference to the drawings. fi+ is a spherical glass material with +21 riI11 part and longitudinal principal meridian 1-'
The position in the I' direction is shown. Spherical glass material (11
consists of a convex lens, whose front surface +31 and back surface (4
) consists of a spherical surface with parallel curvature surfaces.

The manufacturing method of the present invention is manufactured using semi-finished products of glass materials such as the moon, but of course, the glass materials of It is made in advance through processing, etc.
It can also be an integrated process starting from the glass plate. However, in the case of this embodiment, the spherical surfaces of the front surface (3) and back surface (4) of the glass material (11) are delivered with relatively rough surfaces.

Therefore, the preparation process in the manufacturing method of the present invention begins by first polishing the glass material (110 spherical surface) to a glossy finish by grinding and polishing.

FIG. 2 is a longitudinal cross-sectional view showing the state in which the surface of the spherical glass material (1) is rough-machined, and the glass material (1) is attached to the lower lens holder (5) and rotates. The upper plate (6) K is rotated with a ring-shaped diamond abrasive grain (71 attached thereto), and rough cutting is performed without applying cutting oil. The back side is also processed using the same method.

The following figure 3 shows the spherical glass material +l for rough cutting.
This is a vertical cross-sectional view showing the state in which the surface of the r is subjected to smoothing processing, and diamond pellets (9) (9) are attached to the surface of the concave smoothing plate (8) and rotated. On the other hand, on the lens arm O1]l, a spherical glass element lfi+' for rough cutting υ is attached to a lens holder aD and reciprocated, and it is also possible to finish the lens without sprinkling cutting oil. The back side is also processed in the same way.

The final figure 4 is a vertical cross-sectional view showing the state in which the surface of the spherical glass material (1f) of the smoothing processing upper part is subjected to the bolus processing.Hard polyurethane abrasive grains are also placed on the surface of the concave lower plate α2. The plate 113 is attached and rotates.On the other hand, the lens arm (141) has a smoothed spherical glass element u tl!' attached to the lens holder (IS
It is attached and reciprocated to remove an abrasive such as cerium oxide and perform polishing operations such as boring. The back side is also processed using the same method.

Figure 5 shows the fireproof mold [161 (al
They are a top view and (b) a longitudinal sectional view. The refractory mold 4161 may be a mold, but in this embodiment, it is made of an inorganic refractory material. This fireproof type (161) has a cylindrical shape with a diameter matching the diameter of the glass material, and is a combination of a base curved type Oη and a near curved type 081.

The pace curved surface type α has a thick wall as shown in Fig. 5(b), the bottom is a disk shape with a convex spherical surface with good stability, and the surface is made of a glass material with a curvature. A convex spherical distance curved part (17a) having a radius of curvature of 81H with no diopter of the same degree as the radius, and a progressive side curved part (17b) with astigmatism from distance to near vision on both sides thereof. (17b). Further, a cylindrical groove of 55 nφ is bored below the center and the lower half, leaving the bottom surface intact.

What is important here is that the opening angle of the fireproof type (17a') is 120 with respect to the center (C) of the curved surface of the fireproof type (161).
9 to 1b -o'' (i4140° in the case of the example), and in the case of the example, it is in an upward arc shape, which is 120°. This is because if the width exceeds 160°, the change in astigmatism becomes severe.The mold of the present invention has the desired distance curved part (i7a) as described above and the progressive side curved part (17a).
b) The feature is that (17b) is already made of one piece. Also, the diameter of the entire fireproof type (16) is approximately 70 mm.
The cylindrical groove of 351nIφ for flφ passes through the center 2
The tangent line corresponds to around 100°.

The circular groove is combined with a near-use curved surface type 0υ whose circular outer edges are at the same height (it is necessary to mark each in the longitudinal direction of the principal meridian so that both marks fit together).

When the near curved surface type [181] is combined with a diameter of 345flφ, the boundary between them is hardly noticed and the same surface is maintained. The radius of curvature of the near vision curved surface type a8 is a convex spherical surface of 50H in this embodiment, which has a small radius of curvature that matches the power of the reading glasses.

Place the glass material (1) on top of the base curved mold (171) and fireproof mold (161) in which the near curved mold holder is combined, aligning the 11th meridian of the mold and the main material.At this time, , the diameter of the fireproof type is larger than the diameter of the spherical glass material, so the fireproof type protrudes more, but as shown in Figure 5 (a)
) The material is placed as shown in (1) of the fireproof type (161). The spherical glass material (1) is placed above the fireproof type αG, leaving a part of the near curved type α mark, so when viewed from the side it looks like the shape shown in Figure 6, but does not touch the mold. It will have an empty capacity of 111Ji (V).Although it is not shown, it is placed on a moving fireproof conveyor and placed into a heating furnace at a speed of about 1117FL per hour.The heating furnace is , glass material (1)
The softening temperature of 690°C to 695°C is maintained, but depending on the material, the softening temperature may be around 650°C or 700°C.
In some cases, it is kept above ℃. After molding in a heating furnace for about 7 hours, the glass material (nothing is placed on top of 11, but it softens to the extent that it does not melt) and becomes a pace curved type (1η and near curved type α). Formed along the combined curvature of the ears, a glass material α after processing is obtained, and the void l!J(vl is eliminated).

In this process, the back surface of the glass material 0-Y has the curvature of the distance curved part (17a) of the base curved surface type aη and the progressive side curved part (17b) (17b), although the side view is not shown. The base back surface (2Oa) along the curve, the former being 81R in the case of this example, and the near vision back surface (2ob) along the curvature of the near curved surface type aδ, 5QR in the case of this example, are formed, while the glass The surface of the material (11) is also a parallel smooth curved surface along the same curvature as a whole, and in this example, the thickness of the material is 7 m, so the base surface (21a) is 88R1 or the near surface. (21b) F157R.In the end, it is no exaggeration to say that the purpose of heat molding is to form a curved surface on the front surface (21a) (211-), and on the back surface (20a) (20b) i After that, the curvature is adjusted by polishing according to the power and aberration.The glass material used for processing after this is slowly cooled.Then, as before, The three steps of rough cutting, finishing, and polishing are performed for about 90 seconds, 4 to 10 minutes, respectively.

After that, the lens is coated and inspected, and the multifocal lens of the present invention manufactured in this manner is as shown in FIG. (2) is the waist, 1-1' is the position of the longitudinal principal meridian, and the progressive part centered at ψ), while the upper part is the distance part (
L), and its opening angle (θ1.)tri 12
16o0 within 0° (1400 in the example). It has become. The boundary line (22
For a) (22b), a distorted curve as shown in FIG. 8 is ideal. The plane is the near part, and the opening angle (θ2) is 100°.
The front and rear sides are arched downward with reverse distortion. Fireproof type [16
The near curved surface type Q81 of No. 1 had a circular shape with a diameter of 34.5, but in order to be placed on top of it as shown in Fig.
Boundary line (23a) (23b) of the anti-cup-shaped curve as shown in the figure K
Glass material V! is finished by polishing. This is because the near vision area is wide and easy to use. Of course, it is expressed as a boundary line, but it is essential for the progressive multifocal lens of the present invention to have a smooth finish so that the position of this boundary is not noticeable.

Then, along the longitudinal principal meridian, claw-shaped progressive sides (Ps) (Ps) similar to a power distribution curve are formed on both sides, divided into the upper part for distance vision and the lower part for near vision. A gentle astigmatism is performed. The claw-like frequency distribution curve referred to here refers to a curved distribution with an inflection point on at least one peak, or a normal distribution curve with inflection points on both peaks, which is an inversely skewed downward arc. This is a phrase that goes like this.

FIG. 9 shows the thus finished multifocal lens marked for right and left eyes. The molding process of the present invention is for the right eye (river) and the left eye (after both eyes are used with the same fireproof type, the vertical principal meridian and the geometric center (24R)
24L) and perpendicular to the horizontal reference IN (2sa)(
2sD), its upper IK eyepoint (26R) (2
6L) is symmetrical on both the left and right sides. For the right eye (published near vision mark (27Ft)) Fi 5 degrees to the right about the vertical principal meridian 1-.1', while for the left eye the near vision mark (27Ft)
) is marked about 5 degrees to the left with respect to the longitudinal principal meridian 1-1'. This is the near vision mark (27R) (270
) The finish of the core is classified according to the type of finish.

The multifocal lens of the present invention as in the above embodiment has the following characteristics. ■The distance viewing area is wide and there is little distortion in the periphery. ■The field of vision in the near vision area is wider than in the conventional model.■Asymmetrical distortion in the near vision area is reduced.

The lens of the present invention is a seamless progressive multifocal lens that replaces conventional bifocal lenses.
You must master how to move your eyes and adapt it to that.

In this respect, when moving up and down in the visual field i1, all of the lenses of this kind currently on the market have no boundaries and are natural. The problem lies in the swaying that occurs when the face moves from side to side.This part is on the progressive side, and the key is to change the part where the line of sight does not go smoothly. It is characterized by having a progressive side with each opening angle set in an ideal range. To put it simply, the near vision area is wide and easy to use, the vision maintains a gradual progression, and the distance vision area is as wide as possible without any hindrance.

It can be said that the reason why the lens of the present invention is able to have such an ideal area allocated to each part is due in part to the manufacturing method. The key is to use a combination type of fireproof mold for heat molding. This type of lens for presbyopia needs to be prepared in various types (for example, 10 types each) with different dioptric power in the near vision area, but since it is not possible to prepare highly accurate types, the performance is 5 to 50%. I couldn't get a lens for it.

In the manufacturing method of the present invention, a near curved surface mold whose surface has a curvature for the near vision portion is separately produced, while the same pace curved surface mold is used in combination. The lens mounting method has also been improved. Of course the bass song□゛Side 1
The molds may be 111g, but molds of the same size may be made as many as the near curved molds and combined in advance. In any case, the combination mold used in the manufacturing method of the present invention has extremely high precision. Therefore, the lens of the present invention has been mass-produced with high precision.

[Brief explanation of drawings]

Figure 1 is (a) a plan view of the spherical glass material used in the manufacturing method of the present invention, (b) a sectional view taken along the line A-A' in Figure 1 (a), and Figure 2 is the main view of the spherical glass material used in the manufacturing method of the present invention. A vertical cross-sectional view showing the state of the surface agent used after the manufacturing method of the invention, FIG. 3 is a vertical cross-sectional view showing the state of the surface finishing process, and FIG. FIG. 5 is a perspective view of the swing polishing machine, and FIG. The cross-sectional view, FIG.
Figure 5 (F) shows the state in which Figure 1 (b) is placed, i
+, high ゛□1□□, *7 [gt1@61ii! 1. A vertical cross-sectional view of the glass material after the molding process; FIG. 8 is a front and front view illustrating each part of the multifocal lens of the present invention, and FIG. 9 shows a state in which the multifocal lens of the present invention is marked. (R) Plan view of the lens for the right eye, (Ll Plan view of the lens for the left eye, 1st
FIG. 0 is a plan view illustrating each part of a multifocal lens showing a conventional example, and FIG. 11 is a plan view illustrating each part of a multifocal lens showing another conventional example.゛In the figure = (month/
... Spherical glass material, a... Fireproof type, mark, (1
-1')...Longitudinal principal meridian, 4)...Continuous part, (N)
...Near vision part, tP)...Progressive part, (Ps)...Progressive side part, (θ1)...Aperture angle of distance vision part, (θ2)
...Opening angle of the near vision area. 2nd time

Claims (1)

[Scope of Claims] 1. A multifocal lens for spectacles having a distance portion above the longitudinal principal meridian, a near portion below, and a progressive portion in the middle where the power changes continuously. , the distance portion has an opening angle of 12
0° to 160°, and the near portion is formed into a reverse distortion downward arc shape with an opening angle of around 100° via the progressive portion;
A multifocal lens characterized by having wedge-shaped progressive sides on both sides of each part. 2. The near vision area of the right eye lens is 5 points with respect to the longitudinal principal meridian.
Claim 1, characterized in that the lens for the left eye is provided front and back by 5 degrees to the right, and the lens for the left eye is provided to the front and back by 5 degrees to the left.
Monofocal lens as described in section. 3. In a method for manufacturing a multifocal lens for eyeglasses, which includes the step of placing at least a spherical glass material on a fireproof mold and processing it in a heating furnace, the fireproof mold is the base. It consists of a combination of a curved type and a near-use curved type, and the boundary surface of both curved types is the same plane, and a spherical glass material is placed on top of the fireproof type. 1. A method for manufacturing a multifocal lens, comprising the step of molding the lens in a heating furnace. 4. The pace curved surface has a distance portion with an aperture angle of 120° to 160° above the longitudinal principal meridian, and a progressive side in the shape of a cone on both sides with a progressive portion in the middle. In addition, a circular hole with a bottom was bored in the lower part, and the two tangent lines passing through the center of the spherical glass material had an opening angle of about 100°, and the holes were fitted into the circular hole with a bottom. A refractory mold is used, which is a removable combination of a near curved mold whose boundary surfaces are in the same plane, and a spherical glass material is placed on top of the refractory mold and molded in a heating furnace. 4. The method of manufacturing a multifocal lens according to claim 3, further comprising the steps of: 5. When placing a spherical glass material on a large-sized spherical glass material, the fire-resistant mold is made of a material larger than the spherical glass material, and a part of the lower near-use curved shape of the fire-resistant mold is left behind. Claim 3, characterized in that a spherical glass material is placed above so that the spherical glass material can contact the near curved surface shape in a reverse distortion type downward arc shape with a wide tail. Fourth
2. Method for manufacturing a multifocal lens described in Section 1. 6. Molding a lens for the right eye and a lens for the left eye using one type of fire-resistant mold, and then moving the main material after the processing 1) toward the right or left side by about 5 degrees below the sagittal line; 4. The method of manufacturing a multifocal lens according to claim 3, wherein the lens is made into a right-eye lens or a left-eye lens by marking a usage mark.