JPS5818330B2 - Manufacturing method for meniscus lenses for eyeglasses - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of ophthalmic lenses and other products that require surface treatment to obtain ophthalmic properties, and in particular to semi-finished and partially finished ophthalmic lenses.

Conventional glass eyeglass lenses are made from cut pieces of fused glass material (
gob), rond material or sheet material into a shape close to the final product by pressurizing, casting or drop molding, that is, sluffing (s
It was made by grinding and polishing both sides of a semi-finished product formed by a method such as lumping.

When making prescription (Rx) eyeglass lenses, one side of the semi-finished lens is usually optically polished and the other side is further ground and polished to a predetermined spherical or compound curved surface (center thickness) depending on the prescription of the Rx lens. Finish.

Semi-finished lenses are usually supplied to eyeglass lens manufacturers and finished with various curvatures, but this process involves multiple stages of grinding,
Polishing and cleaning operations are time consuming and require complex equipment.

Therefore, the high manufacturing costs of ground and polished semi-finished products contribute to the current high cost to consumers of final eyeglass lenses,
Also, lengthy grinding and polishing operations are a significant impediment to Rx lens distributors' requirements for inventory of semi-finished lenses.

In order to overcome the above-mentioned deficiencies of high costs and long production schedules, the present invention uniquely avoids grinding and polishing operations during the production of semi-finished and semi-finished ophthalmic lenses.

The present invention also provides a newly created can made of crow material.
e) Overcoming the drawbacks of surface defects that occur during casting or hot pre-lensing.

Lenses made by conventional cane casting or melt molding are useful as condenser lenses, but cannot be used as spectacle lenses or imaging lenses (objective lenses).

In addition to the applicability of the invention to the production of semi-finished ophthalmic lenses, the method of the invention is also applicable to the production of finished ophthalmic lenses that do not require at least grinding and/or polishing operations.

Of course, the term "finished" in this specification refers to a lens or other product regardless of whether or not the edges have been cut, ground, or punched to obtain the final peripheral shape;
means a product with smoothness).

The term ``other products'' is intended to include glass articles that require high polishing on one or both sides, such as non-ophthalmic lenses, Kasuri, prisms, and electronic picture tube faceplates.

The object of the invention is to first produce a preform of the lens or glass article to be manufactured, i.e. by making a preform consisting of a main glass of the thickness of the object and a chemically soluble protective glass of greater thickness. When achieved, this protective glass is fused by a smooth, defect-free interface on at least one side of the primary glass.

The preformed article is punched or otherwise cut, pressed or sloughed to form the desired shape of the finished article, and the protective glass is removed with a suitable solvent to expose the smooth, defect-free surface underneath. .

Particularly in the production of eyeglass lenses, a fused laminated lens consisting of a main glass and a soluble protective glass is formed into the meniscus shape required for eyeglass lenses by pressing or sloughing, and then
The protective glass is removed by etching and the tank can be used immediately for eyeglasses without any additional surface treatment.

The invention will be explained below with reference to the accompanying drawings.

The invention will now be described in particular detail with reference to embodiments of the manufacture of semi-finished and finished ophthalmic lenses as shown in FIGS. 1 and 2, respectively.

Of course, these examples do not limit the present invention,
It will be appreciated by those skilled in the art that various modifications and applications of the present invention may be made to produce products other than lenses with special requirements, such as those requiring high polishing on one side or more than one side. To explain this, this lens has a surface finish suitable for spectacles on only one surface, that is, the concave or convex surface.

This type of lens is used by an Rx (prescription) lens vendor, who grinds and polishes the other surface of this semi-finished lens 10 to the desired thickness, spherical radius, or other specifications as described above.
An Rx lens is made with a compound curvature that combines the curvatures of two surfaces.

For example, if the convex surface 12 is considered to be the finished surface of the semi-finished lens 10 (FIG. 1), the manufacturer grinds and polishes the concave surface 14 to a thickness and curvature as shown by the dashed line 16 to produce the finished spectacle lens 10.
′ (Figure 2).

Lens 10' has the same finished surface 12 of lens 10 and a freshly ground and polished surface 16/.

The edges of the completed lens 10' are then cut and/or polished to the desired shape for attachment to the rim of an eyeglass frame and mounted to the eyeglass frame in the conventional manner for final use.

This peripheral polishing and mounting of the eyeglass lens is not part of the present invention, so a description thereof will be omitted.

The terms "glass finish" and "glass properties" as used herein with respect to the lens surfaces obtained with the present invention refer to the exceptional smoothness necessary to produce optimal visual acuity in use; It also means smoothness, which has been used in the industry for many years.

This type of surface is usually inspected for smoothness by comparison with a predetermined reference surface, optically or otherwise, and is referred to above as a "spectacle finish".
Alternatively, "eyeglass properties" refers to a surface texture, ie, smoothness, that meets or exceeds current standards required for high performance eyeglass tanks.

These surfaces shall have a glossy finish and be virtually free of holes, stains, scratches, small divots ("orange shading" defects) or other discontinuities and corrugations.

The manufacturing method for the semi-finished lens of the type shown in Figure 1 is as follows.
and shown in Figure 6.

In particular, FIG. 3 shows the basic glass structure, preformed article 1.
One method and apparatus for making 8 is shown, and from this preform a semi-finished lens such as that shown in FIG. 1 is made.

The apparatus of FIG. 3 includes a tank 20 containing molten glass material (eg, ophthalmic crown glass) 22 from which semi-finished lenses are made in accordance with the present invention.

The tank 20 may be the final chamber of a continuous glass making furnace, with the glass material 22 at a predetermined level 2 above the outlet orifice 26.
4 or higher.

The height of the orifice 26 (distance between the two arrows 27 in FIG. 3) is approximately equal to the predetermined thickness of the glass 22 in the preform 18, and its width is equal to the desired width or diameter of the semifinished lens to be manufactured. equal to or slightly greater.

Also, the width of the orifice 26 may be twice or more than three times the approximate diameter of the semi-finished lens to be manufactured.

The glass 22 of the preform 18 exiting the orifice 26 is conveyed and suspended over a bath 28 of molten metal (e.g., tin) while simultaneously being coated with a relatively thin coating of leachable, i.e., chemically soluble, glass 30. Ru.

This latter glass is supplied in molten form from a separate tank 32 having a rectangular orifice 34 positioned such that the glass 30 covers substantially the entire width of the glass 22 and whose size and shape are controlled. can.

The construction and operation of tank 32 may be similar to tank 20 described above, or it may be of any other suitable construction in which the coating of molten glass 3o is provided.

In addition to being chemically soluble, the glass 30 has properties that are compatible with the expansion coefficient and softening temperature of the glass 22, and is selected in advance so that the glasses 22 and 30 can be smoothly interfacially fused to obtain the preformed bacteria 18. do.

The preformed bacteria 18 float over a molten tin bath 28 over a length of about a few meters and are then pulled by support and traction rollers 84.

This suspension of preformed bacteria 18 causes the interface 36 between glasses 22 and 30 to be precisely flattened and smoothed.

This flattening and smoothing of pre-formed bacteria 18 occurs in tanks 20 and 3.
This is easily accomplished by adjusting the rotational speed of the rollers 84 relative to the crow flow rate from 2 and applying a small traction force to the preformed bacteria 18.

With this device, the interface 36 is flattened to visual precision.

U.S. Pat. No. 3,220 details the "floating glass" manufacturing process used to create flattened glass products with a smooth finish.
, No. 816, No. 3,356,478 or No. 3,413
, No. 107.

After passing the roller 84, the preformed bacteria 18 follow the arrows 37.37
Lens forming station 3 in the direction of '(Figures 3 and 4)
Sent to 8th.

At this station, a lens semi-finished product 40 is cut from the preformed microorganism 18 by saw cutting or punching using a tool 42 or the like.

In cases such as saw cutting, the preformed bacteria 18 is typically cooled to a relatively hard state during its transfer from the rollers 84 to the station 38.

In the case of punching using tool 42', the preformed microorganisms are maintained in a relatively flexible state at least until reaching station 38, or heated to a suitable degree of constriction at a location adjacent to station 38. .

The semi-finished product 40 cut from the preformed bacteria 18 is sent to a forming station, indicated generally at 42 in FIG. 4, where it is formed into the desired shape, typically a meniscus shape.

At this stage, the cut out semi-finished product 40 is transferred to the conveyor 4.
4 and is moved to a forming station 42 and placed separately into a forming mold 46, or this mold is made of cast iron,
Made of heat-resistant steel or a refractory material such as non-metallic ceramic or silicon carbide.

Conveyor 48 moves the loaded mold to station 42 where semi-finished product 40 is given a shape consistent with the curved forming surface of inner mold surface 50.

This shaping of the semi-finished product 40 is facilitated by heating it at station 42 sufficiently to cause it to be drop formed against the mold surface.

Alternatively, a plunger 52 having the desired curved surface 54 presses and shapes the semi-finished product.

The plunger 52 may be preheated if necessary.

From the above explanation, it can be seen that the process of flattening the glass 22 of the pre-formed bacteria 18 (Fig. 3), the manufacturing of semi-finished products and the molding process (Fig.
During the whole process of Fig. 2, the surface of the interface 36 of the crow 22 is completely protected by the crow 30, so that there are no scratches, small dents ('orange dents') and particulate foreign matter inclusions, which result in small irregularities. It will be appreciated that it is maintained in a defect-free condition.

For example, if there are defects such as dots and/or particulate foreign objects, scratches, and streaks on the molding surface 54 of the plunger 52, correspondingly small dents and streaks would appear on the surface of the semi-finished lens product if the protective glass 30 were not present. occurs in

However, the protective glass 30 prevents these surface defects from reaching the interface, so that the surface of the semi-finished product 40 is free from defects.

The semi-finished lens is completed by removing the protective glass 30 from the molded semi-finished product 40 to expose the surface 56.

In any case, this operation yields a semi-finished lens of the type shown in FIG. 1, with the exposed surface 56 of the semi-finished product 40 becoming the finished surface 12 of the semi-finished lens.

Removal of the protective glass 30 is accomplished by immersing the semifinished product 40 in a suitable chemical leaching solution 58 (FIG. 6), such as a hydrochloric acid solution.

The chemically soluble glass 30 has a compatible coefficient of expansion and softening temperature for use with conventional ophthalmic crown glasses 22 of the preformed microorganisms 18 of the present invention and has the following composition in weight percent: It turned out to be lantern glass or something suitable.

Approximate Weight Factor 8102 12.7 B203 17.2 Approximate Weight Factor Ba0 46 2052 La203 12 The2 9.6 As205 0.5 Other chemically soluble (leachable) glasses that can be used in the practice of this invention are described in U.S. Pat. No. 004,368 and No. 3,
624-. It is described in the specification of No. 816.

Leaching solution 58 (sixth
Figure) was maintained at a temperature of about 65°C with a 5-10% (by volume) hydrochloric acid solution.

Of course, this temperature and concentration can be increased or decreased as desired.

FIG. 7 shows a modification of the device of FIG.

In this apparatus, a protective glass 30 is deposited onto the top surface of a flowing ribbon of glass 22 from a hopper 60 containing a frit 30'.

As glass 22 is pulled over molten metal bath 28,
Frit 301 is deposited at a constant thickness onto glass 22 at the leading edge 62 of orifice 64 of hopper 60 .

The relatively thin layer of frit 30' deposited on the glass 22 almost instantaneously adheres to the glass 22 and forms the interface 36 described above.
form.

The preformed bacteria 18a (Fig. 7) created in this way
and processed into a semi-finished lens by the method shown in FIG.

An alternative method of applying protective glass 30/ to one or both sides of glass 22 is shown in FIG.

In this case, the glass 22 flowing out of the supply tank 20 or 20' is directed into the glass evaporation chamber 66.

The glass evaporation chamber 66 has only one of two chambers, namely 68 and 70, when only one side of the glass 22 is covered with the protective glass 30.

However, in the embodiment of FIG. 8, both sides of the glass 22 are covered with a protective glass 30/.

Of course, within the evaporation chambers 68 and 70 there is a device (not shown) that generates a glass evaporation material or plasma that is deposited on the main glass 22.

This device may be an ion beam sputtering device and/or an electron beam evaporation device.

The former is an ion beam firing gun directed at a source of coating material (protective glass), which bombards the protective glass source with high mechanical energy and fires glass plasma onto the exposed surface of the glass 22.

Evaporation chambers 68 and 70 are where air and waste are discharged (10
'Tall or less).

In the case of electron beam evaporation, an electron beam gun is directed to impact a source of protective glass or other material, emitting a glass plasma onto the glass 22 with low mechanical energy.

A suitable partial vacuum is maintained in both evaporation chambers 68 and 70 by glands γ2 at both ends of evaporation chamber 66.

These glands may be of the mechanical or hydraulic type and the glass 22 can be moved continuously in the direction of arrow 67.

Another embodiment of the invention is shown in Figures 9-12, in which a glass preform 18C (Figure 9) similar to preforms 18, 18a and 18b described above is pulled, fused and Made by equipment that performs roll operations.

In this embodiment of the invention, a rod or slab of glass material (e.g. ophthalmic crown glass) 7 makes up the final lens.
4 is enclosed by a tube, sleeve or continuous layer of a suitable chemically soluble glass 16.

This type of assembly may be prefabricated as a rigid part by casting or other methods, or as described in U.S. Pat.
They can also be made by extrusion of molten glass, such as the glass-coated glass parts described in the '517 patent.

For purposes of illustrating an embodiment of the invention, assume that glass components 74 and 76 of assembly 78 (FIG. 9) are rods and tubes, respectively.
0, the heating element longitudinally heats the assembly 78 until the component glasses 74 and 76 of the towed assembly 78 reach a temperature at which they fuse.

Progressive movement of assembly 78 through the heated zone and traction by rollers 84 causes the fusing unit to taper at 85 and roll to provide preformed bacteria 18C with the desired final thickness and width.

As shown in FIG. 10, the preformed bacteria 18C are obtained from the central lens glass 22 of a predetermined thickness and the tubular glass 76.

and a removable outer covering layer of glass 30.

After the preformed bacteria 18c passes through the roller 84 as necessary,
The smoothness and flatness of the interface 36 (FIG. 10) can also be improved by floating it on a molten metal bath 28 (FIG. 3), such as tin.

This molding is identical in construction to preformed mold 18 or 18a, having a main glass and a single-sided coating, except that preformed mold 18c is completely surrounded on both sides and ends by a removable glass layer 30.

When making semi-finished lenses or finished lenses from the pre-formed bacteria 18c of Figures 9 and 10, flattened halves are formed by saw cutting or punching, similar to the method described above for the semi-finished product 40 of Figures 4-6. Completed product 40a with pre-formed bacteria 1
Cut from 8C.

Excised as above from preformed bacteria 18C.

The semi-finished product 40 with the protective layer 30 is then placed in a forming mold 8
6 (FIG. 12), and when heated by its own weight to a temperature for drop molding, it comes into contact with the surface 88 of the mold 86 and is molded into a shape matching this shape.

Alternatively, the semi-finished product 40 is pressure formed into the shape of FIG. 12 by a plunger 90 having a forming surface 92.

Plunger 90 and mold 86 are heated sufficiently to maintain semi-finished product 40a at a soft state for the forming operation described below.

The semi-finished product 40a formed into a meniscus shape by the drop molding and/or pressure molding described above is finished into a semi-finished lens or a completed lens.

When used as a semi-finished lens (such as lens 10 in FIG. 1), semi-finished product 40a is immersed in a leaching solution for a sufficient period of time to remove protective glass 30.

This leaching operation is carried out in the same manner as the treatment of the semi-finished product 40, as shown in FIG.

In this case, the removal of the two layers of protective glass 30 would occur simultaneously in the leaching operation.

If the semi-finished product 40a (FIG. 13) is used as the lens 10 in FIG.
When it is desired to use the lens as a complete lens, as in '', both the convex and concave surfaces are formed into spherical or compound curved surfaces that match a predetermined surface curvature required for the completed lens.

This is a mold 86 having convex and concave surface curvatures 88 and 92, respectively, corresponding to the curvatures required for the concave and convex surfaces, i.e. 16' and 12, of the final lens to be made from the semi-finished product 40a.
This is done by using the plunger 90.

To make the finished lens, the semi-finished product 40a is soaked in a suitable leaching solution 58 for a sufficient period of time to remove both protective glass layers 30.
(Figure 6).

As mentioned above, the protective glass 30 prevents defects on the surface of the underlying main lens glass 22 during lens manufacture according to the principles of the present invention, and when it is removed from the lens, the underlying protected surface no longer becomes It can be used for eyeglasses without the need for grinding and/or polishing.

Removal of the chemically fusible glass protective layer 30 when making semi-finished or finished lenses can of course be delayed until after all processing operations for these lenses have been completed.

In other words, the manufacturing of semi-finished lenses involves grinding and polishing one surface (e.g., surface 14 of lens 10 in FIG. 1) and final shaping the edges to the desired shape and size for attachment to an eyeglass frame. Additional grinding or polishing operations may be completed prior to removal of the protective layer 30.

For example, when manufacturing a finished lens of the type shown in FIG. 2, the protective layer 30 can be left in place until the edges have been ground or polished for mounting the lens in a spectacle frame.

The thickness of the main glass of the lens semi-finished product 40 or 40a is usually several times the thickness, but the thickness of the protective glass layer 30 is usually only a few times the thickness of one shoe.

However, these dimensions are merely examples and can be increased or decreased depending on the purpose of use.

Also, although the temperatures used to obtain a viscosity suitable for flotation, traction, fusing, and meniscus shaping of the crows 22 and 30 are not described in detail, one skilled in the art will appreciate the specific temperatures used in the practice of the invention. Depending on the softening temperature of the glass, the temperature suitable for the above operation may be determined.

The operating temperature of the glasses 22 and 30 described above is approximately 1050° to 1350°C.

Extrusion and flotation of these glasses may require higher temperatures.

However, pulling and forming (pressing) operations could be carried out at lower temperatures.

The embodiments of the present invention are listed below.

(1) In the method described in the claims, the first glass layer is formed by making the glass material flowable, placing the glass material on a floating medium bath and suspending the material, and pulling the material from the bath. A method of manufacturing lenses made by flattening between traction movements.

(2) In the method described in paragraph (1) above, the process of covering the first glass layer with the second glass layer is carried out continuously as the first glass layer is floated and pulled in the floating medium bath. A lens manufacturing method performed by supplying the second glass material onto the first glass layer.

(3) In the method described in paragraph (2) above, the second glass layer is initially in a fritted state and is melted onto the first glass layer as the first glass layer is floated and pulled on the floating medium bath. A lens manufacturing method in which a fixed amount of lenses is supplied in one state.

(4) A method for producing a lens according to the method described in the claims, wherein the process of flattening the preformed bacteria includes a process of rolling the first and second glass layer combinations.

(5) In the claimed method, a first layer of preformed bacteria is formed of a hard glass of the desired article, and a second layer is formed of at least one other hard glass bonded to the first layer of glass. a process in which the pre-formed bacteria is formed of glass and reduces its cross-sectional area by heating and pulling the first and second layer combination, and rolling the heated and pulled combination into a desired flattening process; A method of manufacturing lentils made by a process of imparting a shape to the pre-formed bacteria.

(6) In the claimed method, the process of coating at least one side of the first glass layer is obtained as a second layer by condensation of glass vapor directed onto the first glass layer, and the pre-formed bacteria are removed. Lens manufacturing method.

(A method for producing a lens according to the method described in the claims, wherein heating and softening of a part of the pre-formed bacteria and molding process are performed before the process of cutting out the part from the pre-formed bacteria.

(8) A method of manufacturing a lens as claimed in the claims, wherein the step of removing the coated glass layer is carried out by exposing the glass layer to a chemical leaching medium.

(9) A method for manufacturing a lens having an ophthalmically characteristic finish on at least one surface, the lens being made of the type of glass required for the lens;
and forming a first glass layer having at least the thickness, width and length required for the lens; during the forming process of the first glass layer, a relatively thin second glass layer of removable glass; coating and fusing this at the interface with the first glass layer to form a combination of first and second glass layers that are preformed bacteria of the lens; at least a portion of the preformed bacteria; softening and molding to form a meniscus shape; and removing a second glass layer from a portion of the pre-formed bacteria to expose the surface of the ten first glass layers as a finished surface of the lens. A lens manufacturing method.

00) A method for producing a lens using the method described in item (9) above, which includes a step of flattening a portion of the preformed bacteria before forming a portion of the preformed bacteria into a meniscus shape.

Brief Description of the Drawings Figure 1 is a sectional view of a typical semi-finished eyeglass lens made by the method of the present invention; Figure 2 is a sectional view of a completed eyeglass lens obtained from the semi-finished lens of Figure 1; Figure 3 FIG. 4 is a schematic cross-sectional view of the apparatus and method for carrying out the initial steps of the invention; FIG. FIG. 5 is a cross-sectional view of the lens obtained by the process of FIGS. 3 and 4; FIG. 6 is a schematic diagram showing another process for making the lens of FIG. 5 according to the present invention; FIGS. 7, 8, and 9 are FIG. 10 is a cross-sectional view taken along line 10--10 of FIG. 9; FIG.
and 7F in Figure 10 are cross-sectional views of pre-formed bacteria produced by the modified method of the present invention; Figure 12 schematically shows operations applied to the pre-formed bacteria shown in Figure 11 during lens manufacture;
FIG. 13 is a cross section of a semi-finished lens obtained by the modification method of the present invention shown in FIGS. 9-12, from which a semi-finished product of a completed or semi-finished spectacle lens can be obtained.

18... Preformed bacteria, 22... Main glass, 28...
- Molten contact metal bath, 30... Protective glass layer, 36... Interface, 40... Semi-finished product, 58... Leaching solution.

Claims (1)

[Claims] 1 having at least one finished surface having ophthalmic properties 1
In a method of manufacturing a mirror lens: forming a first layer of glass of the type required for the lens and having at least the length, width and thickness required for the lens; coating at least one side of one layer with a relatively thin second layer of removable glass during the first layer formation process, and interfacially fusing the second layer glass with the first layer to bond both of them. creating a preformed article with bonded layered glass; precision flattening of said preform so as to obtain a finish having ophthalmic properties on a first layer of said preform adjacent to a second layer; softening and molding at least a portion of the preform into a shape approximating the desired shape of the lens; and removing the second coating layer from the preform to provide the finished surface of the lens. 1st
A method for manufacturing a meniscus lens for spectacles, comprising: exposing the surface of the layer.