Drying Nozzle Segmentation for Contact Lens Edge Uniformity
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Solution Overview
Problem
The existing methods for inspecting the peripheral portion of contact lenses, particularly the lens edge, often misinterpret water droplets as defects due to uneven drying, leading to unnecessary rejections.
Innovation Solution
A drying nozzle with a continuous annular outlet gap for even air distribution effectively dries the lens edge, ensuring accurate inspection by preventing false defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressurized air is applied through nozzles with discrete openings to dry the contact lens, then the lens is dried, but water droplets remain on the lens edge causing dark portions that are misinterpreted as defects
Solution Approach 1:
The nozzle is divided into multiple discrete openings (e.g., 3-5 openings) arranged circumferentially around the lens periphery. Each opening independently directs pressurized air at specific segments of the lens edge, ensuring complete coverage while maintaining uniform drying across the entire lens periphery.
Solution Approach 2:
The nozzle provides locally concentrated streams of pressurized air from discrete openings positioned at specific locations around the lens. This localized air delivery ensures that each region of the lens edge receives adequate drying attention, eliminating water droplets that would otherwise cause dark portions in the inspection image.
2Productivity
If the lens edge is not evenly dried, then inspection time is reduced, but false defect detection increases leading to unnecessary rejections
Solution Approach 1:
The drying operation is performed immediately before the inspection step, ensuring the lens edge is completely dry prior to imaging. The multiple discrete openings deliver pressurized air in advance of inspection, removing all water droplets that would interfere with accurate defect detection, thereby preventing false rejections without compromising inspection speed.
3Ease of manufacture
If a continuous annular outlet gap is used instead of discrete openings, then air distribution becomes more even, but the nozzle structure becomes more complex
Solution Approach 1:
Instead of a continuous annular gap, the outlet is segmented into multiple discrete openings (e.g., 3-5 openings) distributed circumferentially. This segmentation maintains structural simplicity while achieving uniform air distribution across the lens periphery, as each opening targets a specific region and collectively they provide complete coverage.
Solution Approach 2:
The nozzle design parameters (number, size, and angular spacing of discrete openings) are optimized to achieve uniform air distribution. By adjusting these parameters, the system attains drying uniformity comparable to or better than a continuous annular gap, while maintaining simpler manufacturing and allowing easier cleaning and maintenance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces unjustified rejections by ensuring the lens edge is evenly dried and represented brightly in high contrast images, enhancing the production process efficiency.
Implementation Method 1
a stream of pressurized air, in particular pressurized, is capable of being supplied through the continuous annular outlet gap onto the peripheral portion of the ophthalmic lens
Data Source
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AI summary
A drying nozzle (1) for drying a peripheral portion of an ophthalmic lens (CL), in particular a contact lens, comprises an inlet (30) for the supply of a pressurized, and a continuous annular outlet gap (11) having a predetermined width (W), central bore (fig.8) (313a) and a concave upper surface (314a) which converges toward the outlet opening of the central bore (313a), through which the pressurized air is capable of being supplied to the peripheral portion of the ophthalmic lens (CL).