Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/38—Moulds or cores; Details thereof or accessories therefor characterised by the material or the manufacturing process
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D11/00—Producing optical elements, e.g. lenses or prisms
  • B29D11/00009—Production of simple or compound lenses
  • B29D11/00028—Bifocal lenses; Multifocal lenses
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D11/00—Producing optical elements, e.g. lenses or prisms
  • B29D11/00009—Production of simple or compound lenses
  • B29D11/00413—Production of simple or compound lenses made by moulding between two mould parts which are not in direct contact with one another, e.g. comprising a seal between or on the edges
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D11/00—Producing optical elements, e.g. lenses or prisms
  • B29D11/00009—Production of simple or compound lenses
  • B29D11/00432—Auxiliary operations, e.g. machines for filling the moulds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D11/00—Producing optical elements, e.g. lenses or prisms
  • B29D11/00009—Production of simple or compound lenses
  • B29D11/0048—Moulds for lenses
  • B29D11/00528—Consisting of two mould halves joined by an annular gasket
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
  • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
  • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
  • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
  • B29C2035/0827—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using UV radiation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2909/00—Use of inorganic materials not provided for in groups B29K2803/00 - B29K2807/00, as mould material
  • B29K2909/08—Glass

Definitions

• plastic In manufacturing lenses, and particularly lenses for use with eye glasses, the use of plastic is often desirable due to its weight and durability.
• two molds in conjunction with the gasket are sealed in a spaced relationship to provide a mold cavity there between. This mold cavity ultimately forms the shape, curvature, thickness and configuration of the product lens.
• Plastic material is dispensed into the mold cavity and cured to harden the lens with the exterior surfaces being configured to a particular patient's prescription.
• the mold forms which actually constitute the mold have been in the past made of metal or glass which are grovuid or formed to the desired shape to create the prescription made by the optometrist, ophthalmologist or other person authorized to do so. Utilizing molds made of metal or glass for this purpose itself is an expensive proposition for both the manufacturer and the user. Whether glass or metal is used it is initially cast and then ground to the desired configuration. A number of different configurations are required to ensure that the desired prescription can be made from these expensive mold forms. These types of mold forms have produced economic and manufacturing impediments to using certain casting processes at particular facilities.
• the plastic lens formed can either be a semi-finished blank needing further surfacing or a lens requiring no surfacing and only finishing to conform the molded item to eyeglass frames or other support structure.
• the invention described herein overcomes many of the problems discussed above.
• an injection molding process is used whereby a liquid monomer material is injected into a submaster cavity which will ultimately form the newly fabricated mold.
• the plastic, or other material used in forming the mold, utilized in producing a mold form must provide for the transfer of the optical quality from this mold surface to the material ultimately being molded to form the lens.
• the surface of the mold so formed is optically smooth, without eccentricities.
• the mold plastic must have an affinity to the type of monomer or polymer which is utilized in forming the lens but also release from the polymer following curing.
• a submaster which possesses compensating optical surface and curvature qualities is fixed to the parts of the injection molding apparatus to form the mold into the desired configuration.
• One approach which has proved successful is using electro- formed nickel on a glass substrate to form this optical quality transferring submaster used on the injection molding elements.
• Another embodiment discussed herein is the casting of the material using typical molding techniques.
• the portions of the submaster can be made of metal or glass which have been ground to the necessary surface quality.
• the sub aster ⁇ are placed in opposed relationship to form a cavity there between and sealed with respect to one another so that the molding material can be received in a sealed relationship.
• no pressure is required to dispense the molding material into the cavity making the system relatively easy to use and more economical from an initial investment.
• any type of curing process can be employed in the casting technique such as ultra violet or thermal curing.
• compression molding is used to form the molds.
• a malleable material which will be used in manufacturing the mold form is partially formed into a configuration similar to the form it will have when subsequently molded.
• the malleable material can be made using one of the other processes discussed above or any other process which will produce a form of optical quality. It is then placed into a submaster which is held in place by a support member. A compression member is then actuated to press the malleable material against the submaster to obtain the desired configuration.
• Figure 1 is a side view of an injection molding apparatus.
• Figure 2 is a section of the molding apparatus shown in Figure 1 taken along lines 2-2.
• Figure 3 is an enlarged section of figure 2 taken along lines 3-3.
• Figure 4 is a cross section of the mold formed by the processes of invention.
• Figure 5 is a cross section of the casting apparatus.
• Figure 6 is a schematic of the compression apparatus in a open position.
• Figure 7 is a schematic of the compression apparatus in a closed position.
• Element 14 carries submaster molds 16 and element 12 carries a complementary submaster molds of 18.
• FIG. 2 there is shown central opening 30 in fluid connection with channels 32 which are in turn connected to cavities formed by submaster mold elements 16 and 18.
• the fluid monomer will enter through central opening 30 and pass outwardly through channel 32 to the respective cavities as shown.
• injection molding elements 12 and 14 will be displaced or opened to permit the molded forms to fall away and be collected for subsequent use.
• the submaster molds 16 and 18 used in this particular embodiment are electro formed nickel on a glass substrate.
• Mold form 18 includes a convex molding surface 24 which includes a bifocal element 28.
• the rear surface 26 as shown is generally concave, but does not have to be of any particular surface characteristic since it is not interface with the material being molded.
• the complementary submaster 16 includes a concave surface 20 which is complementary to convex surface 24 of the mold member submaster 18.
• the molds are configured and cooperate with elements 12 and 14 to define between surfaces 20 and 24, as shown in Figure 3, a cavity therebetween corresponding to a lens of a selected prescription.
• the liquid monomer will be injected into the cavity between the mold surfaces 24 and 20.
• the injection molding elements are opened, and the mold form 34, as shown in Figure 4, is removed.
• Complementary form can be molded in a similar manner to achieve another interior surface with which the form 34 would ultimately be used.
• the plastic mold forms formed by the injecting molding process discussed above will come in many different configurations so that the optometrist or other user making a prescription and ultimately casting the lens will have a sufficient number of forms to choose from in obtaining the desired prescription for the patient.
• the monomer or polymer is simply cast into a casting or mold 40 formed from glass or metal.
• a casting or mold 40 formed from glass or metal.
• two submaster mold elements 42 and 41 are shown in opposed relationship to form cavity 43 therebetween by the surfaces 44 and 48 respectively.
• one of the submaster mold forms 42 includes a portion 46 which corresponds to the bifocal element on a bifocal lens.
• the submaster mold forms 41 and 42 are made of glass although they could be made of metal.
• the interior opposed surfaces forming cavity 43 in mold 40 are either ground or polished to insure that they impart optical quality surfaces to the plastic which is dispensed into the cavity.
• the material to be molded such as plastic monomer is injected into cavity 43.
• the mold can be cured by ultra violet light or thermal or both assuming the necessary initiators are utilized in the composition of the molding material.
• monomers and polymers are utilized as discussed above molten glass or other material which can achieve the desired optical qualities can be employed.
• Another form of casting is to use a layering process where a submaster has a layer of liquid monomer placed on the mold surface. This layer is then subjected to an ultraviolet or thermal curing process to harden the layer. The process is then repeated until a sufficient thickness has been accumulated to permit the layered form to be used as a mold. Once the desired thickness is obtained, the mold form is simply peeled away from the submaster.
• Another embodiment is one of compression molding.
• the advantage of use of compression molding is that the step of actually forming is a relatively simple one and avoids the need for accurate curing to change the polymer and cure it to a hardened form within and achieve the desired surface quality.
• the support member 52 has a submaster mold surface 54 which will ultimately form one surface of the mold form.
• This particular submaster 54 includes an extended portion of 56 which corresponds to a bifocal element on the lens ultimately formed.
• Complementary press 58 is arranged above the support member 52 with the mold 60 material thereon.
• the mold material 60 in . this instance is malleable and, will have the same characteristics as the mold material discussed above insofar as optical qualities are concerned.
• the press 58 is simply forced against the mold material as can be seen in Figure 7 to press it into the desired configuration. Since the submaster mold surface of 54 is in the desired configuration it will cause the material being molded to achieve substantially the same configuration for use as a disposable mold form 62.
• the various mold forms will all be shipped in containers to the user's location.
• the user will select the desired mold forms for each surface of the lens front surface and rear surface.
• These mold forms are then arranged in a gasket and utilized in a typical casting process to cast the lens form that is desired.
• the monomer is then dispensed into the cavity formed by the mold forms arranged in the gasket. After curing the casted lens can simply be removed, the edges ground and placed in the glass frames for use by the patient.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Health & Medical Sciences (AREA)
• Ophthalmology & Optometry (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (3)

Cited By (1)

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Citations (2)

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• 1989
  • 1989-05-31 WO PCT/US1989/002359 patent/WO1989011966A1/en not_active Application Discontinuation
  • 1989-05-31 JP JP1506591A patent/JPH03502908A/ja active Pending
  • 1989-05-31 EP EP19890906944 patent/EP0377020A4/en not_active Withdrawn

Patent Citations (2)

Non-Patent Citations (2)

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