Contact Lens Formulation Dosing for Precise Mold Centration
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Solution Overview
Problem
Existing methods for manually dosing lens formulations in contact lens fabrication result in inconsistent dosing, imprecise centration, and distortion, leading to product inconsistencies and visual distortions.
Innovation Solution
A system comprising a carrier portion and alignment mandrel for precise positioning of center and edge lens formulation delivery devices, ensuring accurate delivery of formulations to a contact lens mold, with the center formulation as a circular dot and edge formulation as a ring-shaped pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual dosing with pipettes is used, then operation simplicity is maintained, but dosing precision and centration accuracy deteriorate
Solution Approach 1:
The patent introduces a dosing device with a pipette as an intermediary tool between the operator and the mold. The pipette is held in a fixture that positions it at a precise, predetermined distance from the mold surface, ensuring consistent dosing depth and location. This intermediary mechanism maintains operational simplicity while achieving manufacturing precision through mechanical positioning features.
Solution Approach 2:
The patent replaces manual freehand pipetting with a mechanically constrained dosing system. The fixture provides mechanical guidance and positioning for the pipette, eliminating the variability of manual operation. This substitution of uncontrolled mechanical action with controlled mechanical positioning resolves the contradiction between ease of operation and dosing precision.
2Device complexity
If manual dosing with pipettes is used, then device complexity is minimized, but centration accuracy deteriorates
Solution Approach 1:
The fixture acts as an intermediary device that provides centration functionality without requiring complex active control systems. The mechanical design of the fixture inherently guides the pipette to the correct position on the mold, achieving accurate centration through passive mechanical means rather than complex active positioning mechanisms.
Solution Approach 2:
The dosing device is designed to self-position and self-align on the mold through mechanical features such as tapered surfaces and engagement geometries. The system performs its own positioning function without requiring external alignment tools or complex control systems, thereby maintaining low device complexity while achieving high centration accuracy.
3Device complexity
If manual dosing with pipettes is used, then equipment cost is reduced, but product consistency deteriorates
Solution Approach 1:
The patent replaces variable manual mechanical operations with consistent mechanical positioning. The fixture provides repeatable positioning of the pipette relative to the mold, ensuring that each dosing operation is identical to the previous one. This mechanical consistency eliminates the variability introduced by manual operation, thereby improving product consistency without requiring expensive automated systems.
Solution Approach 2:
The fixture establishes and maintains critical parameters such as dosing distance, dosing angle, and dosing location at optimal fixed values. By controlling these parameters mechanically rather than allowing them to vary with manual operation, the system achieves consistent dosing results and improved product reliability while keeping the equipment simple and cost-effective.
Data Source
AI summary
A dosing system and method for delivery of contact lens formulation(s) to a contact lens forming mold. The system includes a carrier portion configured for holding a contact lens mold, and an alignment mandrel configured for retaining a lens formulation delivery device. The lens formulation delivery device is retained in a specified position relative to the contact lens mold for precise location of delivery of the lens formulation within the contact lens mold. A first lens formulation can be dosed to a center location in the mold, and a different second lens formulation can be dosed to a ring-shaped pattern around the center location, to form a contact lens having different center and edge characteristics.