Static molds – Including coating or adherent layer
Reexamination Certificate
2000-08-24
2002-12-10
Silbaugh, Jan H. (Department: 1722)
Static molds
Including coating or adherent layer
C249S160000, C425S215000, C425S806000, C425S808000
Reexamination Certificate
active
06491281
ABSTRACT:
This application is based on Japanese Patent Application Nos. 11-241142 filed Aug. 27, 1999, and 2000-227446 filed Jul. 27, 2000, the contents of which are incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mold assembly for forming an ophthalmic lens article and a method of forming the same using the mold assembly. More particularly, the present invention is concerned with such a mold assembly suitably used for forming the ophthalmic lens article including an ophthalmic lens and an intermediate product for the ophthalmic lens, and such a method for forming the ophthalmic lens article using the mold assembly.
2. Discussion of Related Art
There are known methods for producing a so-called ophthalmic lens article such as ophthalmic lenses, which include contact lenses and intraocular lenses, or an intermediate product for the ophthalmic lens, which includes a lens blank having one of opposite surfaces with a configuration which follows that of a corresponding one of front and back surfaces of the intended lens while the other surface needs to be cut to form the other of the front and back surfaces of the lens. One method used to form the above-discussed lens products includes the steps of: (a) preparing a mold assembly consisting of a first mold and a second mold in the form of a male mold and a female mold or an upper mold and a lower mold, which are closed or assembled together so as to define therebetween a mold cavity having a configuration following that of the intended ophthalmic lens article; (b) polymerizing a suitable polymeric material which fills the mold cavity defined between the first and second molds, so as to form the intended ophthalmic lens article in the mold cavity; and (c) separating the first and second molds from each other, so as to remove the ophthalmic lens article formed in the mold cavity from the mold assembly.
In the method described above, since the ophthalmic lens article in the form of a polymerized product, which is obtained by polymerization of the polymeric material in the mold cavity, adheres to one of the first and second molds, the ophthalmic lens article is held on the above-indicated one of the two molds when they are removed away from each other. It is, however, quite difficult to predict on which of the two molds the formed ophthalmic lens article will be held since there is no consistency as to which of the two molds the ophthalmic lens article will be held. Moreover, it is impossible to control the formed ophthalmic lens article to be held on and adhere to a desired one of the two molds.
Accordingly, it is conventionally required to check on which of the two molds the formed ophthalmic lens article is held when the two molds are separated away or moved apart from each other, considerably deteriorating production efficiency of the ophthalmic lens article. Since the ophthalmic lens article does not consistently remain on and adhere specifically to one of the first and second molds, it is quite difficult to automate a process of removing the formed ophthalmic lens article from the mold assembly. Accordingly, the ophthalmic lens article cannot be manufactured in an automated manner. If the intermediate product for the ophthalmic lens article adheres to either one of the two molds at one of it's the mold's opposite surfaces, it will be necessary to determine which surface needs to be processed to provide the corresponding one of the front and back surfaces of the intended ophthalmic lens article. In order to accomplish this, the intermediate product needs to be first removed from the mold, and then held and supported by a suitable holder for processing the above-indicated surface which has adhered to the mold. This undesirably deteriorates the production efficiency of the ophthalmic lens article.
In view of the above, there have been recently proposed various techniques which permit the formed ophthalmic lens article to be held on and adhered to a predetermined one of the first and second molds of the mold assembly when the first and second molds are separated away from each other.
One example of such techniques is JP-A-7-80860, which discloses a mold assembly consisting of a male mold and a female mold for forming an intermediate product for a contact lens. The male mold of the mold assembly disclosed in this publication has a protrusion or a recess formed in its molding surface having a profile following that of a back surface of the contact lens, in an attempt to improve an adhesive strength of the molding surface for holding the molded intermediate product thereon. When the intermediate product is formed by using the thus constructed mold assembly, the molded intermediate product adheres to and is held on the male mold every time when the two molds are separated away from each other. The male mold, however, inevitably has a complicated shape due to provision of the protrusion or recess on its molding surface, as compared with a male mold without such a protrusion or recess. In the mold assembly disclosed in the above publication, the shape of the male mold is undesirably limited to a specific design which permits the protrusion or recess to be formed on its molding surface, making it difficult to form the contact lens having an intended configuration. JP-A-7-195558 discloses a mold assembly consisting of a male mold and a female mold for forming a contact lens, wherein a region of a molding surface of at least one of the male and female molds is pre-treated by corona-discharging, such that the region of the molding surface interposed between a pair of electrodes is subjected to a corona discharge, for thereby improving an adhesive strength of the molding surface for holding the formed contact lens thereon. In the thus constructed mold assembly, the formed contact lens adheres to and is held on one of the male and female molds having the pre-treated molding surface every time when the male and female molds are separated away from each other.
Unlike the mold assembly disclosed in JP-A-7-80860 wherein the molding surface of the male mold is formed into a specific shape having the protrusion or recess as described above, the mold assembly of JP-A-7-195558, wherein the molding surfaces of the male and female molds do not have such a protrusion or recess, permits the ophthalmic lens article to be formed into a desired configuration.
In the mold assembly disclosed in JP-A-7-195558, however, an expensive corona-discharge device is used for pre-treating the molding surface of at least one of the male and female molds to improve the adhesive strength of the molding surface for holding the formed contact lens thereon. For effecting the pre-treatment on the molding surface of the at least one mold with high efficiency, the electrodes are shaped to follow the configuration of the mold, so that the electrodes can be positioned as close as possible to the mold. Accordingly, the arrangement disclosed in the publication undesirably pushes up the cost of manufacture of the contact lens due to the use of the expensive corona-discharge device and the specially prepared electrodes. In a series of process steps for the pre-treatment on the molding surface of the at least one mold, it is cumbersome to position the electrodes as close as possible to the mold. In addition, if the electrodes contacted the molding surface, the molding surface would be damaged. Moreover, the pre-treatment on the molding surface of the mold is effected by applying a considerably high voltage to the electrodes, causing a risk of injuring the workers who are engaged in the pre-treatment operation.
SUMMARY OF THE INVENTION
The present invention was made in the light of the background art described above. It is a first object of the present invention to provide a mold assembly consisting of a first mold and a second mold for forming an ophthalmic lens article, wherein the ophthalmic lens article formed in the mold assembly adheres to and is held on a molding surface of a predetermined one of the first
Gotou Yuuji
Matsuda Yasushi
Burr & Brown
Heckenberg Donald
Menicon Co. Ltd.
Silbaugh Jan H.
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