contact lens mold

Abstract

The invention discloses a contact lens mold. The contact lens mold comprises an upper mold and a lower mold, wherein the bottom surface of the upper mold has a convex optical surface, a boundary convex surface, an opposite concave surface and an upper embedded surface symmetrical to a hypothetical center line from center to periphery in sequence; the distance from any point of the upper embedded surface to the hypothetical center line is D; the top surface of the lower mold has a concave optical surface, a boundary convex surface, a first opposite concave surface and a lower embedded surface symmetrical to the hypothetical center line from center to periphery in sequence; the distance from any point of the lower embedded surface to the hypothetical center line is d; when the upper and lower molds are not combined, D is greater than d; and when the upper and lower molds are combined, the upper embedded surface and the lower embedded surface are destructively clamped, so that the upper and lower molds can be stably combined to improve the contact lens production yield.

Description

technical field [0001] The invention relates to a mold, in particular to a mold for contact lenses. Background technique [0002] Generally, the mold for manufacturing contact lenses is formed by joining an upper mold and a lower mold. There is a cavity between the upper mold and the lower mold, and a polymer material can be poured into the cavity and heated or heated. It is cured and shaped by light, and after the cured polymer material is released from the mold, it can become a contact lens product after softening treatment. [0003] However, the above-mentioned polymer materials will generate volatile gas during heating or light irradiation. When the volatilization speed is too fast, the air pressure formed by the volatile gas will easily push the upper mold upward, causing the upper mold to shift, which not only affects the upper and lower molds The joining of the upper and lower molds will also cause the problem of lens deformation and other problems that lead to a dec...

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Problems solved by technology

[0003] However, the above-mentioned polymer materials will generate volatile gas during heating or light irradiation. When the volatilization speed is too fast, the air pressure formed by the volatile gas will easily push the upper mold upward, causing the upper mold to shift, which not only affects the upper and lower molds The joining of the upper and lower molds will also cause the problem of lens deformation and other problems that lead to a decrease in yield; in order to solve the above defects, some manufacturers will use a fusion device to fuse parts of the upper and lower molds together, so that the upper and lower molds can be firmly combined and prevent volatility. The gas pushes the upper mold to make it shift, etc.

[0004] However, the above structure still has the following disadvantages: (1) the fusion equipment is expensive, which greatly increases the cost of making contact lenses; (2) after the polymer material is solidified, the upper and lower molds need to be cut by a cutting equipment to cut the fusion site , so that the upper and lower molds are separated to take out the polymer material, so the production process of the contact lens becomes cumbersome, which affects the production capacity

[0005] In addition, for the contact lens mold disclosed in Taiwan Invention Patent No. M487831, the manufacture of the upper and lower molds is relatively difficult and complicated. Not only is the cost high, but the dimensional error often exceeds the allowable value. When the error exceeds the allowable value, the bonding of the upper and lower molds will be affected, and the two are prone to eccentricity, which will affect the yield of the lens

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