CN111300855A - Interferometric contact lens molds and methods of forming lenses - Google Patents

Abstract

The invention discloses an interference type contact lens mold and a method for forming lenses, which relate to the technical field of contact lenses. A lens cavity is arranged between the two sides for forming a lens; the outer side of the male mold is provided with a first interference ring zone, and the inner side of the female mold is correspondingly provided with a second interference ring zone; the first interference ring zone and the A first rough surface and a second rough surface are respectively provided on the surface of the second interference ring band, and the first rough surface and the second rough surface can be interference fit. The invention utilizes the first rough surface and the second rough surface for interference fit, and then cooperates with a servo motor and a pressure sensor to perform adjustable equal-weight balance pressing; a cutting ring is used to form a lens cavity separated from the inside and outside, and the two rough surfaces are used to pass The overfitting is used to limit the setting, so that the lens and the remaining material are completely cut off; finally, the lens with smooth edges and balanced thickness in the center is obtained, which makes consumers more comfortable to wear.

Description

A kind of interference type contact lens mold and method of forming lens

technical field

The present invention relates to the technical field of contact lenses, in particular to an interference type contact lens mold and a method for forming lenses.

Background technique

At present, the production process methods of soft contact lenses include: turning method, centrifugal rotary mold method, die-casting mold method and mixed process method.

The turning method, the centrifugal rotary die method, and the mixed process method are now used less and less. The die-casting method has the advantages of good repeatability, mass production, low cost, and smooth lens surfaces and edges. It has become the mainstream process of contact lens production, but it also has its own shortcomings and shortcomings. There are three main ways to form lenses: the first self-priming method is to use the self-adsorption force of the contact lens monomer. The adsorption force keeps the lens monomer and the remaining material disconnected to form a separate lens; the second welding method is to use gravity to press the male and female molds, and then use a heating wire to weld the male and female molds to limit and shape, so as to keep the inner and outer monomers completely cut off to form a complete Lens; the third method of buckle is to use gravity to press the male and female molds, and then use the concave (convex) ring measured inside the female mold to cooperate with the convex (concave) ring on the outside of the male mold to limit the interaction to keep the inner and outer monomers completely cut off form a complete lens.

Although all three methods can form ideal lenses, they all have their own shortcomings. The self-priming method should be relatively stable after filling and pressing before curing, and there should be no jitter. The mold itself swings, and the conveyor belt needs to run at a constant speed, otherwise the edge of the lens will not be easily cut, affecting the production yield and increasing the production cost; although the welding method solves the problem The disadvantages of the self-priming method, but increase the welding disk, increase the probability of equipment failure, and generate gas during welding, which pollutes the workshop environment and affects product quality. The disadvantages of the two methods, but after pressing the buckle to limit, due to the different shrinkage ratio of the male and female molds, the buckle itself is displaced up and down when the buckle is fitted, which makes the center thickness of the lens obtained after the two molds are pressed together. If the thickness is different, if the upper mold is pressed too hard, the upper mold will move downward. Although the lens is cut off, the thickness of the center of the lens is too thin, which will cause failure outside the standard. The edge of the formed lens cannot be cut off. Even if it is cut off, the lens will have thick and thin edges, which will affect the wearing comfort. At the same time, the center thickness of the lens may exceed the standard and cause failure, as shown in Figure 9-13. For example, the above structures and methods are proposed in Chinese invention patent CN101791864B and Chinese utility model patent CN204222086U, respectively.

Therefore, there is an urgent need to provide an interference type contact lens mold and a method for forming a lens to solve the above problems in the prior art.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an interference type contact lens mold and a method for forming a lens, so as to solve the problems existing in the above-mentioned prior art. The formed lens can maintain a constant center thickness, a balanced edge and other advantages, so that the production cost is reduced and consumers are comfortable to wear.

In order to achieve the above object, the present invention provides the following solutions: the present invention provides an interference type contact lens mold, including a female mold and a male mold, the male mold is located above the female mold, the female mold and the male mold are provided. A lens cavity is arranged between the molds for forming a lens; a first interference ring band is arranged on the outer side of the male mold, and a second interference ring band is correspondingly arranged on the inner side of the female mold; the first interference ring band and the A first rough surface and a second rough surface are respectively provided on the surface of the second interference ring band, and the first rough surface and the second rough surface can be interference fit.

Preferably, the material of the female mold and the male mold is one or more of PP, PE, PMMA, PU, PET, PBT or PC materials; the female mold and the male mold are made of the same or different materials to make.

Preferably, the first interference ring belt is provided with exhaust grooves, there are three exhaust grooves, and the three exhaust grooves are evenly distributed along the circumference.

Preferably, the torus of the first rough surface has an outward angle of 0°-2° from top to bottom, and the torus of the second rough surface has an inward angle of 0°-2° from bottom to top ° angle.

Preferably, the surface roughness Ra of the first rough surface and the second rough surface is 1.00-100.

Preferably, the outer side of the male mold is provided with a guiding angle, and the inner side of the female mold is correspondingly provided with a guiding front surface.

The present invention also discloses a method for forming a lens, comprising the following steps:

1) Prepare the body material of the lens;

2) According to the design requirements, inject the female and male molds to be used later, and place the fabricated female and male molds for later use;

3) Fill the body material of the lens in the female mold, and then cover the male mold for pressing;

4) Enter the oven for thermal curing to form lenses;

5) Separate the negative and male molds with dry lenses to take out the lenses, extract the unpolymerized residual material, and finally package and market.

Preferably, when making the body material of the lens in the step 1), 95%-98.4% of hydroxyethyl methacrylate, 1%-3% of hydrophilic agent, 0.5%-1% of cross-linking agent, initiator 0.1%-1% of the agent is mixed, and stirred for 2 hours under the condition of 0-5 degrees, filtered and refrigerated for later use.

Preferably, in the step 1), hydroxyethyl methacrylate and hydrophilic agent are respectively added under the condition of 0-5 degrees, after stirring for 1 hour, the cross-linking agent is added and stirred for 0.6 hours, and the initiator is added to continue stirring for 0.4 hours. hours, filter and refrigerate for later use.

Preferably, in the step 4), an adjustable equal weight balance pressing is performed by a servo motor and a pressure sensor; during the pressing process, the air generated by the reduced space is discharged along the exhaust groove; the female mold and the male mold are used. The cutting ring forms a lens cavity separated from the inside and the outside. The first rough surface and the second rough surface are used for the interference fit to limit the shape. The body material and residual material of the lens are completely cut off.

The present invention has achieved the following technical effects with respect to the prior art:

The invention not only has the advantages of good repeatability, mass production, low cost, smooth lens surface and simple process; it can also maintain a constant center thickness, a balanced edge, and eliminate welding fumes, so as to ultimately reduce production costs, Consumers wear comfortably.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the male mold structure schematic diagram of the present invention;

Fig. 2 is the male mold 3D figure of the present invention;

Fig. 3 is the structure schematic diagram of the female mold of the present invention;

Fig. 4 is the male mold of the present invention, female mold assembly schematic diagram;

Figure 5 is a schematic view of the present invention's male mold, female mold pressing (the lens has been finalized);

6 is a schematic diagram of a molded lens of the present invention;

7 is a schematic view of the lens slice angle structure of the present invention;

8 is a schematic view of the structure of the lens slice edge of the present invention;

9 is a schematic diagram of the structure of the corner (when the pressure is too heavy) in the prior art;

10 is a schematic diagram of the structure of the corner (when the pressure is too light) in the prior art;

11 is a schematic diagram of the structure of the center thickness (when the pressure is too heavy or too light) in the prior art;

FIG. 12 is a schematic diagram of the structure of a corner and a side (when the center is pressed to the left) in the prior art;

Figure 13 is a schematic diagram of the structure of a corner and side (when the center is pressed to the right) in the prior art;

In the picture: 10 male mold, 20 female mold, 30 male mold and female mold combination, 40 lens, 101 first interference ring belt, 102 first interference ring belt lower chamfer, 103 upper surface of male mold, 104 leading angle , 105 male optical surface, 106 exhaust groove, 201 second interference ring belt, 202 second interference ring belt upper chamfer, 203 female mold lower surface, 204 lead front, 205 female mold optical surface, 206 female mold cutting ring , 301 interference fit surface, 302 exhaust cavity, 303 guide fit, 304 excess material cavity, 305 cutoff line, 306 lens cavity, 401 lens left corner, 402 lens right corner, 403 lens left non-optical edge, 404 lens Right non-optical side, 4011 left corner of the lens when the pressure is too heavy, 4021 right corner of the lens when the pressure is too heavy, 4012 left corner of the lens when the pressure is too light, 4022 right corner of the lens when the pressure is too light, 405 lens center thickness, 4051 When the pressure is too heavy, the lens Center thickness, 4052 is the center thickness of the lens when the pressure is too light, 406 is the left corner of the lens when the center is pressed to the left, 407 is the right corner of the lens when the center is pressed to the left, 408 is the left corner of the lens when the center is pressed to the right, and 409 is when the center is pressed to the right. The right corner of the lens, 4010 is the left non-optical edge of the lens when the center is pressed to the left, 4011 is the right non-optical edge of the lens when the center is pressed to the left, 4012 is the left non-optical edge of the lens when the center is pressed to the right, and 4013 is the center of the right. The right non-optical edge of the lens.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Example 1

As shown in FIGS. 1-8, the present embodiment provides an interference type contact lens mold, including a female mold 20 and a male mold 10, the male mold 10 is located above the female mold 20, the female mold 20 and the A lens cavity 306 is provided between the male molds 10 for forming the lens 40; a first interference ring 101 is provided on the outer side of the male mold 10, and a second interference ring 201 is correspondingly provided on the inner side of the female mold; A first rough surface and a second rough surface are respectively provided on the surfaces of the first interference ring band 101 and the second interference ring band 201 , and the first rough surface and the second rough surface can be interference fit. , forming an interference fit surface 301 ; further, a lower chamfer 102 of the first interference ring is arranged below the first interference band 101 , and an upper chamfer 202 of the second interference ring is correspondingly arranged on the second interference band 201 .

In this embodiment, the materials of the female mold 20 and the male mold 10 are one or more of PP, PE, PMMA, PU, PET, PBT or PC materials; the female mold 20 and the male mold 10 are made of Made of the same or different materials.

In this embodiment, the first interference ring belt 101 is provided with exhaust grooves 106 , there are three exhaust grooves 106 , and the three exhaust grooves 106 are evenly distributed along the circumference.

In this embodiment, the torus of the first rough surface has an outward angle β of 0°-2° from top to bottom, and the torus of the second rough surface has an inward angle from bottom to top The included angle β of 0°-2°.

In this embodiment, the surface roughness Ra of the first rough surface and the second rough surface is 1.00-100 μm.

In this embodiment, the outer side of the male mold 10 is provided with a guiding angle 104, the inner side of the female mold 20 is correspondingly provided with a guiding face 204, and the joint of the guiding angle 104 and the guiding face 204 is the guiding fitting 303 .

This embodiment also discloses a method for forming a lens, comprising the following steps:

1) The body material of the prepared lens: 95%-98.4% of hydroxyethyl methacrylate, 1%-3% of hydrophilic agent, 0.5%-1% of cross-linking agent, 0.1%-1% of initiator, etc. Stir for 2 hours at 0-5 degrees, filter and refrigerate for later use, pay attention to the order of raw materials.

Specifically, MA can be selected as the hydrophilic agent, GMA can be selected as the crosslinking agent, and AIBN can be selected as the initiator; HEMA (hydroxyethyl methacrylate) and MA are respectively added under the conditions of 0-5 degrees, and after stirring for 1 hour, GMA is added. After stirring for another 0.6 hours, add AIBN to continue stirring for 0.4 hours, and finally filter and refrigerate for later use.

The composition ratios of the body materials of the lenses in this embodiment are as follows:

Mold design, injection molding, pairing of male and female molds, dripping of lens body materials and pressing and curing:

2) According to the design requirements, use a high-precision lathe to process the steel mold and then cooperate with the injection mold to form the female mold 20 and the male mold 10 for subsequent injection molding. Specifically, a high-precision lathe above 80 is used to process the contact lenses according to the design The steel mold core is assembled on the steel mold after the steel mold core is processed, and finally the whole set of molds is installed on the injection molding machine for injection molding of the plastic mold; The mold 10 is placed for use; after the male mold 10 and the female mold 20 are closed, they are stored in a clean environment for use, as shown in Figure 4, or the male mold 10 and the female mold 20 can be placed separately and concentratedly. When the male mold 10 is placed Care should be taken to protect the optical surface 105 of the male mold, as shown in FIGS. 1-3 ; the positions where the female mold 20 and the male mold 10 contact the lens cavity 306 are the optical surface 205 of the female mold and the optical surface 105 of the male mold.

3) Fill the sheet material of the lens 40 in the female mold 20, and then cover the male mold 10 for pressing; the assembled male mold 10 and the female mold 20 need to take out the male mold 10 to fill the female mold 20 with sheet material, Then return to the male mold 10 for pressing; the molds stored separately can be taken out of the female mold 20 and directly filled and covered with the male mold 10 and pressed together.

Pressing is the key process. Specifically, the first rough surface and the second rough surface are used for interference fit, and the roughness of the two rough surfaces is Ra (1-100), and both rough surfaces have 0°-2°. Slope; and then cooperate with the servo motor and pressure sensor to perform adjustable equal weight balance pressing, among which the adjustable equal weight balance pressing uses the pressure sensed by the adjustable pressure sensor during the downward pressing to feed back to the servo motor, so that the servo motor goes down, Actions such as stopping, ascending, etc.; once a pressure value is set, the subsequent pressure is kept constant, and the pressing jig needs to be processed with high balance precision; the air generated by the reduction of the space during pressing follows the 3 of the male die 10. The strip exhaust groove 106 is exhausted, and the female mold cutting ring 206 is used to form the lens cavity 304 separated from the inside and outside, and then the first rough surface and the second rough surface are used for interference fit to limit and shape; Specifically, the female mold cutting ring 206 is designed A protruding corner ring is formed by the intersection of the two sides and the male mold 10 is pressed together, and the residual material cavity 304 and the lens cavity 306 are formed by cutting the dividing line 305.

At the same time, the guide angle 104 and the guide face 204 are used to guide the pressing process of the male mold 10, so that the formed lens 40 is not eccentric, the center thickness 405 of the lens is uniform, and the thickness of the left non-optical edge 403 and the right non-optical edge 404 of the lens Symmetrical, the left corner 401 of the lens and the right corner 402 of the lens are uniform, so that the lens material and the remaining material are completely cut off.

4) Enter the oven for thermal curing to form lenses;

5) Take out the lenses separately from the female mold 20 and the male mold 10 with dry lenses, and use water and related solvents to extract the unpolymerized residual material, and finally package and go on the market; Ethyl acetate, acetone, etc.

This embodiment not only has the advantages of good repeatability, mass production, low cost, smooth lens surface, and simple process, but also maintains a constant center thickness, balanced non-optical edge thickness, and eliminates welding fumes. Ultimately, the purpose of reducing production costs and making it comfortable for consumers to wear is achieved.

A cross-section section test is performed on the lenses produced in this example:

Ten pieces of lenses 40 produced in this embodiment and ten pieces of lenses produced by existing related processes are taken, and the cross-sectional slices thereof are compared and tested. Observing the sliced sample with a solid microscope with a magnification of 50, the results are shown in FIG. 6 , the lens 40 produced in this example is fully hydrated, fully stretched, and the radian and edges and corners transition naturally. In this embodiment, the left non-optical edge 403 of the lens, the right non-optical edge 404 of the lens, the left corner 401 of the lens, and the right corner 402 of the lens (as shown in FIGS. 7 and 8 ) are more over-pressed than those produced by the existing process when the pressure is too heavy. The left corner 4011 of the lens when the pressure is too heavy and the right corner 4021 of the lens when the pressure is too heavy (as shown in Figure 9), the left corner of the lens 4012 when the pressure is too light in the prior art and the right corner 4022 of the lens when the pressure is too light (as shown in Figure 10). When the process pressure is too heavy, the center thickness of the lens is 4051, and when the pressure is too light, the center thickness of the lens is 4052 (as shown in Figure 11). In the existing process, the left corner of the lens 406 when the center is pressed to the left and the right corner 407 of the lens when the center is pressed to the left. The left non-optical edge 4010 of the lens when the center is pressed to the left and the right non-optical edge 4011 of the lens when the center is pressed to the left (as shown in Figure 12), the left corner 408 of the lens and the center of the lens when the center is pressed to the right in the prior art The right corner 409 of the lens when the center is pressed down, the left non-optical edge 4012 of the lens when the center is pressed down to the right, and the right non-optical edge 4013 of the lens when the center is pressed down to the right (as shown in Fig. Uniformity, consistency, and goodness; it shows that the lenses produced in this example have obvious improvements in performance, parameters, stability, etc. compared to the lenses produced by the existing process, and finally achieve lower production costs, comfortable wearing for consumers, and healthy consumption. Purpose.

Embodiment 2

This embodiment is an improvement on the basis of the first embodiment, and its improvement lies in:

The composition ratios of the body materials of the lenses in this embodiment are as follows:

Embodiment 3

This embodiment is an improvement on the basis of the first embodiment, and its improvement lies in:

The composition ratios of the body materials of the lenses in this embodiment are as follows:

In the present invention, specific examples are used to illustrate the principles and implementations of the present invention, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention; There will be changes in the specific implementation manner and application scope of the idea of the invention. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (10)

1. An interferometric contact lens mold comprising a female mold and a male mold, the male mold being positioned above the female mold, a lens cavity being provided between the female mold and the male mold for forming a lens; the method is characterized in that: a first interference annular belt is arranged on the outer side of the male die, and a second interference annular belt is correspondingly arranged on the inner side of the female die; the surface of the first interference annular belt and the surface of the second interference annular belt are respectively provided with a first rough surface and a second rough surface, and the first rough surface and the second rough surface can be in interference fit.

2. The interferometric contact lens mold of claim 1, wherein: the female die and the male die are made of one or more of PP, PE, PMMA, PU, PET, PBT or PC materials; the female die and the male die are made of the same or different materials.

3. The interferometric contact lens mold of claim 1, wherein: the first interference ring belt is provided with three exhaust grooves which are uniformly distributed along the circumference.

4. The interferometric contact lens mold of claim 1, wherein: the ring surface of the first rough surface has an outward included angle of 0-2 degrees from top to bottom, and the ring surface of the second rough surface has an inward included angle of 0-2 degrees from bottom to top.

5. The interferometric contact lens mold of claim 4, wherein: the first rough surface and the second rough surface have a surface roughness Ra of 1.00 to 100.

6. The interferometric contact lens mold of claim 1, wherein: and a positive guide angle is arranged on the outer side of the male die, and a positive guide surface is correspondingly arranged on the inner side of the female die.

7. A method of forming an ophthalmic lens, comprising: the method comprises the following steps:

1) preparing a sheet material of the lens;

2) performing injection molding on a female die and a male die which are used subsequently according to design requirements, and placing the manufactured female die and male die for standby;

3) filling sheet materials of the lenses in the female die, and then covering the male die for pressing;

4) entering a drying oven for thermosetting to form a lens;

5) and (3) separating the female mold with the dry lens from the male mold, taking out the lens, extracting the unpolymerized residual material, and finally packaging and marketing.

8. The method of forming a lens of claim 7, wherein: when the sheet material of the lens is prepared in the step 1), 95% -98.4% of hydroxyethyl methacrylate, 1% -3% of hydrophilic agent, 0.5% -1% of crosslinking agent and 0.1% -1% of initiator are added and mixed, stirred for 2 hours at the temperature of 0-5 ℃, and then filtered and refrigerated for later use.

9. The method of forming a lens of claim 8, wherein: in the step 1), hydroxyethyl methacrylate and a hydrophilic agent are respectively added at the temperature of 0-5 ℃ and stirred for 1 hour, then a cross-linking agent is added and stirred for 0.6 hour, then an initiator is added and the stirring is continued for 0.4 hour, and finally, the mixture is filtered and refrigerated for standby.

10. A method of forming an ophthalmic lens according to claim 1, wherein: in the step 4), adjustable equal-weight balance pressing is carried out through the servo motor and the pressure sensor; in the pressing process, air generated by the reduction of the space is discharged along the exhaust groove; and the female die cutting ring is utilized, the first rough surface and the second rough surface are in interference fit for limiting and shaping, and the positive angle guide and the positive fit surface guide are utilized for guiding the male die in the process of pressing down, so that the sheet material and the excess material of the lens are thoroughly cut off.

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