CN111483099B

CN111483099B - Mold for demolding contact lenses and method thereof

Info

Publication number: CN111483099B
Application number: CN201910073131.5A
Authority: CN
Inventors: 陈志成; 廖显升; 萧旭贵
Original assignee: Unicon Optical Co ltd
Current assignee: Unicon Optical Co ltd
Priority date: 2019-01-25
Filing date: 2019-01-25
Publication date: 2022-05-10
Anticipated expiration: 2039-01-25
Also published as: CN111483099A

Abstract

The invention provides a mold for demolding a contact lens, which comprises a first mold and a second mold, wherein the first mold comprises a mold cavity sunken towards a first direction, a bending section extending outwards from the periphery of the mold cavity, a first mounting part adjacent to the bending section and a sunken section formed between the first mounting part and the bending section, and the wall thickness of the bending section is thinner than that of the mold cavity so as to be matched with the sunken section to help the mold cavity to deform and fold backwards; the second mold comprises a round protrusion part protruding towards the mold cavity and a second mounting part adjacent to the round protrusion part, and an assembly structure is formed between the second mounting part and the first mounting part, so that when the contact lens is demolded by using the mold, the mold cavity can be easily deformed by turning over to complete the demolding.

Description

Mold for demolding contact lenses and method thereof

Technical Field

The present invention relates to a mold, and more particularly, to a mold for manufacturing a contact lens and a method for demolding a contact lens using the same.

Background

The modern contact lens is made by heating or irradiating light to polymerize and solidify liquid contact lens material, and then injecting water to soften the liquid contact lens material.

According to the step process, the turning method, the rotary die casting method, and the die casting method can be further divided. The turning method is to pour the liquid contact lens raw material monomer into a tube, polymerize the monomer into a long rod shape and then cut the long rod shape into a round body of a lens, because the lens can be processed according to different designs, the turning method has the advantage of multiple variability, but because the process steps are complicated and errors are easy to generate, the satisfactory reproduction rate cannot be generated, and the turning method is not suitable for manufacturing contact lenses with larger demand. The rotational molding method is to inject the liquid raw material monomer for contact lens into a rotational mold and rotate the mold, and distribute the liquid raw material monomer for contact lens on the mold through the action of centrifugal force, gravity and surface tension, and the variation of the lens is determined by the injection amount of the raw material monomer and the rotational speed of the mold. The casting method is to place a liquid contact lens raw material monomer between two molds, polymerize it and solidify it into a suitable shape. After the mold is removed, the lens is ground, polished and then soaked in warm water for softening, thus completing the manufacturing of the contact lens. The cast molding method has a high reproducibility and can obtain a thin lens, but has a disadvantage of high cost.

Among the above methods, the mold casting method is most commonly used in recent years. Many manufacturers have developed improvements based on the mold casting process to solve the problems of excess material and mold release during the manufacturing process. For example, chinese patent publication No. CN103465410B proposes an ultrasonic demolding device and a method for manufacturing contact lenses using the same, wherein the ultrasonic demolding device comprises an ultrasonic oscillator, a vibration transmission member, and a mold, so that the ultrasonic demolding device has the advantages of short demolding time, increased production speed, and improved accuracy of subsequent detection process when the demolded contact lenses are in a dry state.

However, there is still room for further improvement in the demolding efficiency in practical use, and there is a need for those skilled in the art to continuously develop and improve the contact lens manufacturing efficiency.

Disclosure of Invention

It is an object of the present invention to provide a mold for manufacturing a contact lens, which can improve the problem that the demolding efficiency of the conventional contact lens manufacturing method using a casting method is not as good as desired.

It is another object of the present invention to provide a method of demolding a contact lens to quickly release the contact lens from the mold during the manufacturing process of the contact lens.

To achieve the above objects, the present invention provides a mold for demolding a contact lens, comprising a first mold and a second mold cooperating with the first mold, wherein the first mold comprises a cavity recessed in a first direction, a bending section extending outward from a periphery of the cavity, a first mounting portion adjacent to the bending section, and a recessed section formed between the first mounting portion and the bending section, and the wall thickness of the bending section is thinner than that of the cavity to cooperate with the recessed section to help the cavity to deform and fold back in a second direction opposite to the first direction; the second mold includes one circular lug projecting toward the mold cavity and one second installing part adjacent to the lug and with one assembling structure formed between the first installing part and the second installing part.

The invention also provides a method for demolding a contact lens by using the mold, which comprises the following steps:

(S1) providing a mold comprising a first mold and a second mold cooperating with the first mold, the first mold comprising a cavity recessed in a first direction, a bending section extending outwardly from a periphery of the cavity, a first mounting portion adjacent to the bending section, and a recessed section formed between the first mounting portion and the bending section, the bending section having a wall thickness thinner than that of the cavity to cooperate with the recessed section to help the cavity to deform and fold back in a second direction opposite to the first direction; the second mould comprises a round protruding part protruding towards the mould cavity and a second mounting part adjacent to the round protruding part, and an assembling structure is formed between the second mounting part and the first mounting part;

(S2) placing a liquid contact lens material in the mold cavity and pressing the lobe of the second mold against the mold cavity;

(S3) separating the first mold and the second mold, so that the liquid contact lens material is adhered to the first mold and shows an arc-shaped film shape; and

(S4) the mold cavity is deformed and folded by folding to complete the mold release.

Accordingly, due to the feature that the wall thickness D1 of the bending section in the first mold is thinner than the wall thickness D2 of the mold cavity, the mold cavity can be easily deformed by folding to complete the demolding in the process of demolding the contact lens by using the mold, so that the manufacturing efficiency of the contact lens can be effectively improved.

Drawings

Fig. 1 is a schematic view of a mold for demolding a contact lens according to an embodiment of the present invention.

Fig. 2 is a schematic view of a first mold of the molds of fig. 1.

Fig. 3 is a schematic view of a second one of the molds of fig. 1.

Fig. 4 is a schematic cross-sectional view of a first mold and a second mold in cooperation with each other according to an embodiment of the invention.

Detailed Description

The detailed description and technical contents of the present invention will now be described with reference to the drawings as follows:

fig. 1 is a schematic view of a mold for demolding a contact lens according to an embodiment of the present invention, which mainly comprises a first mold 10 and a second mold 20, which are capable of cooperating with each other, and in general, in the process of manufacturing a contact lens, liquid contact lens raw material monomers are placed between the first mold 10 and the second mold 20, pressed against each other, and irradiated with light or heat to polymerize and cure the liquid contact lens raw material monomers. Then demoulding, edging, polishing, soaking the lens in warm water for softening and the like to finish the manufacturing of the contact lens. In this embodiment, the material of the first mold 10 and the second mold 20 may be transparent or opaque, and may be a material with some flexibility, such as plastic, for example, but the invention is not limited thereto, and other suitable materials may also be used.

Please refer to fig. 1, fig. 2 and fig. 4. The first mold 10 includes a cavity 11 recessed in a first direction, a bending section 12 extending outward from a periphery of the cavity 11, and an inclined surface 15 formed between the cavity 11 and the bending section 12. The bending section 12 is adjacent to and extends outward to form a first mounting portion 13, and an angle between 10 and 80 is formed between the bending section 12 and the first mounting portion 13.

In this embodiment, the wall thickness D1 of the bending section 12 is thinner than the wall thickness D2 of the mold cavity 11 to match a concave section 14 formed between the first mounting portion 13 and the bending section 12, which helps the mold cavity 11 to be deformed and folded back in a second direction opposite to the first direction.

The mold cavity 11 may be subjected to a hydrophilic treatment such as plasma treatment, flame treatment, or short wave ultraviolet irradiation, so that the contact lens may adhere to the mold cavity 11 when the first mold 10 is separated from the second mold 20 in a subsequent step.

Referring to fig. 1, 3 and 4, the second mold 20 mainly includes a circular protrusion 21 and a second mounting portion 22. The protruding portion 21 protrudes toward the mold cavity 11 of the first mold 10, and includes a neck portion and a curved surface, the neck portion is surrounded by a plurality of bumps 24, and each bump 24 is formed with a notch groove 25 to divide the bump 24 into an upper portion and a lower portion. The indent grooves 25 can be formed, for example, by cutting the bumps 24 by a disc-shaped cutter in a rotating manner to manufacture the indent grooves 25, in this embodiment, each indent groove 25 is formed as a V-shaped indent groove. This design helps to allow excess liquid contact lens monomer to overflow between the indentations 25 and the bumps 24 during the contact lens manufacturing process, and the excess material adheres tightly between the indentations and the bumps after polymerization and curing.

The second mounting portion 22 is formed adjacent to the outer edge of the protruding portion 21, and when the first mold 10 is matched with the second mold 20, the second mounting portion 22 and the first mounting portion 13 form an assembly structure. In this embodiment, the second mounting portion 22 and the lobe 21 are disposed at an angle of between 85 ° and 95 °, such as 90 ° in one embodiment.

The second mounting portion 22 extends in a direction opposite to the protruding portion 21 to form an annular wall 27, a plurality of positioning members 28 can be disposed around the annular wall 27, and a fixed distance can be formed between two adjacent positioning members 28. Thus, when the first mold 10 and the second mold 20 are engaged with each other, a stronger engaging effect can be provided through the annular wall 27.

In this embodiment, when the first mold 10 and the second mold 20 are overlapped with each other, in order to prevent the contact lens disposed therein from being damaged due to over-squeezing, the first mounting portion 13 is further provided with a plurality of first stopping protrusions 16, and the second mounting portion 22 is correspondingly provided with a plurality of second stopping protrusions 26, so that a partial region of each of the second stopping protrusions 26 can contact with the first stopping protrusions 16; or, the size and position of the second stopping projection 26 can also completely correspond to the first stopping projection 16, so that the second stopping projection 26 can completely overlap and contact with the first stopping projection 16, thereby effectively avoiding the damage problem of the contact lens in the manufacturing process. The first stopping protrusions 16 and the second stopping protrusions 26 are respectively disposed on the first mounting portion 13 and the second mounting portion 22 at a fixed interval, in this embodiment, the second stopping protrusions 26 may be disposed corresponding to the positioning elements 28 surrounded on the annular wall 27, but the invention is not limited thereto.

In addition, even when the first mold 10 and the second mold 20 are designed to include many parts, in practice, the first mold 10 and the second mold 20 can be integrally formed by a method such as injection molding, so as to obtain the first mold 10 and the second mold 20, respectively.

Thus, when the contact lens is demolded by using the mold, the mold cavity can be easily deformed by folding to complete the demolding through the following steps S1 to S4:

in step S1, a mold for demolding a contact lens having the structure as described above is provided.

In step S2, a liquid contact lens material is placed in the mold cavity 11 of the first mold 10, and the protrusion 21 of the second mold 20 is pressed downward against the mold cavity 11 until part or all of the second stopping protrusion 26 disposed on the second mounting portion 22 contacts the first stopping protrusion 16 disposed on the first mounting portion 13. At this time, the excess liquid contact lens raw material monomer can overflow to the space between the indented grooves 25 and the bumps 24, thereby preventing the interference of the remainder in the subsequent process.

In step S3, the first mold 10 and the second mold 20 are separated, and the liquid contact lens material will be adhered to the mold cavity 11 of the first mold 10 after being extruded and will present an arc-shaped film.

Finally, in step S4, the mold cavity 11 is folded to deform the mold cavity 11 and then the contact lens is folded in the opposite direction, so as to simply separate the contact lens from the mold cavity 11 to complete the mold release. The specific folding method in this step, for example, because the wall thickness D1 of the bending section 12 is thinner than the wall thickness D2 of the mold cavity 11 of the mold used in this embodiment, the mold cavity 11 can be easily folded and deformed by the force applied from the end protruding from the backside of the mold cavity 11 during operation.

A curing step may be further performed after step S2 or step S3 to cure the liquid contact lens material into a contact lens. The curing step may be a light curing process, such as irradiating the liquid contact lens material with light; or a heat curing process such as blowing hot air to the liquid contact lens material.

Therefore, on the premise of not influencing the yield of the contact lenses, the invention can easily complete the demoulding step by bending and deforming the mould cavity through the design that the wall thickness of the bending section in the mould is smaller than that of the mould cavity, thereby achieving the purpose of improving the manufacturing efficiency of the contact lenses.

The present invention has been described in detail, but the above description is only a preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made according to the scope of the present invention should also be covered by the scope of the present invention.

Claims

1. A mold for demolding a contact lens, said mold comprising:

the first die comprises a die cavity sunken towards a first direction, a bending section extending outwards from one periphery of the die cavity and a first mounting part adjacent to the bending section, an inclined plane is formed between the die cavity and the bending section, an angle between 10 degrees and 80 degrees is formed between the bending section and the first mounting part, a sunken section is formed between the first mounting part and the bending section, and the wall thickness of the bending section is thinner than that of the die cavity so as to be matched with the sunken section to help the die cavity to deform and fold in a second direction opposite to the first direction; and

and the second mould is matched with the first mould, the second mould comprises a round protruding part protruding towards the mould cavity and a second mounting part adjacent to the round protruding part, and an assembling structure is formed between the second mounting part and the first mounting part.

2. The mold of claim 1, wherein the second mold further comprises an abutting section disposed between the round protrusion and the second mounting portion and pressed against the bent section.

3. The mold of claim 1, wherein the lobe and the second mounting portion define an angle therebetween of between 85 ° and 95 °.

4. The mold of claim 1, wherein the protruding portion has a plurality of protrusions, each protrusion having a notch groove formed thereon to divide the protrusion into an upper portion and a lower portion.

5. The mold of claim 1, wherein the first mounting portion has a plurality of first stop protrusions disposed thereon.

6. The mold of claim 5, wherein the second mounting portion has a plurality of second stopping protrusions, such that when the first mold is mated with the second mold, a portion of each of the second stopping protrusions contacts the first stopping protrusion.

7. The mold of claim 1, wherein the second mounting portion extends in a direction opposite to the lobe to form a circumferential wall, and a plurality of positioning members are disposed around the circumferential wall.

8. A method of demolding a contact lens from a mold, the method comprising:

providing a mold, wherein the mold comprises a first mold and a second mold matched with the first mold, the first mold comprises a mold cavity recessed towards a first direction, a bending section extending outwards from one periphery of the mold cavity, and a first installation part adjacent to the bending section, an inclined surface is formed between the mold cavity and the bending section, an angle between 10 degrees and 80 degrees is formed between the bending section and the first installation part, a recessed section is formed between the first installation part and the bending section, and the wall thickness of the bending section is thinner than that of the mold cavity so as to match with the recessed section and help the mold cavity to deform and fold backwards towards a second direction opposite to the first direction; the second mold comprises a round protruding part protruding towards the mold cavity and a second mounting part adjacent to the round protruding part, and an assembling structure is formed between the second mounting part and the first mounting part;

placing a liquid contact lens material in the mold cavity and pressing the lobe of the second mold against the mold cavity;

separating the first mold and the second mold to make the liquid contact lens raw material cling to the first mold and present an arc-shaped film shape; and

and turning over to deform and turn over the die cavity to finish the demoulding.