Ophthalmic Lens Gripper Head for Bubble-Free Liquid Release
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Solution Overview
Problem
Existing gripper systems for ophthalmic lenses, particularly soft contact lenses, face issues such as inconsistent lens pickup due to uneven treatment carriers, lateral displacement of grippers, and misinterpretation of air bubbles as defects during inspection, leading to reduced production yield.
Innovation Solution
A gripper system with a pivotable gripper head, separate suction and liquid supply tubes, and controlled vacuum and liquid overpressure mechanisms to ensure reliable lens transfer and minimize air bubble adherence, using a gripper head made of elastic material to adapt to uneven carriers and release lenses in a liquid environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stiff rigid grippers are used to pick up contact lenses, then the gripper structure is simple and strong, but the gripper fails to pick up lenses from uneven treatment carriers and may damage the lenses
Solution Approach 1:
The gripper head is made from an elastic material (silicone rubber, natural rubber, or fluorinated rubber) with a Shore A hardness between 30 and 90, replacing the traditional stiff rigid gripper. This flexible material allows the gripper head to adapt to uneven surfaces of treatment carriers while maintaining sufficient strength to securely hold the contact lens, thereby solving the contradiction between structural strength and pickup reliability.
2Device complexity
If stiff rigid grippers are used for lens transfer, then the gripper structure is simple, but air bubbles adhere to the lens surface during transfer, leading to misinterpretation as defects
Solution Approach 1:
The system uses a fluid channel connected to a liquid reservoir that supplies liquid to the gripper head during the transfer process. This hydraulic approach replaces the traditional air-based suction mechanism, allowing the lens to be picked up and transported through liquid rather than air, thereby preventing air bubbles from adhering to the lens surface and eliminating false defect detections.
3Ease of operation
If the gripper lowers to a predetermined lowermost axial position to pick up the lens, then the pickup position is fixed, but the gripper may fail to touch the lens if the treatment carrier is slightly curved
Solution Approach 1:
The gripper head's elastic material provides dynamic adaptation to surface variations. Instead of relying on a fixed predetermined position, the flexible gripper head naturally conforms to the actual surface geometry of the treatment carrier (whether flat or slightly curved), ensuring reliable contact with the lens regardless of carrier imperfections while maintaining operational simplicity.
4Reliability
If suction is applied to pick up the lens, then the lens adheres to the gripper, but the lens may be damaged during handling
Solution Approach 1:
The elastic material of the gripper head (with Shore A hardness between 30 and 90) provides a compliant interface that distributes suction forces evenly across the lens surface. This flexibility prevents stress concentration and localized damage while maintaining reliable adhesion, solving the contradiction between pickup reliability and damage prevention.
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
Enhances production yield by preventing lens damage, ensuring consistent pickup, reducing air bubble misinterpretation, and improving inspection accuracy, thereby increasing the number of defect-free lenses transferred to packaging.
Implementation Method 1
a suction tube (14) and a liquid supply tube (15) extending through the hollow inner space of the gripper shaft (10) towards a distal end of the gripper shaft (10), with a distal end of the suction tube (14) and a distal end of the liquid supply tube (15) being arranged in the inner space of the gripper shaft (10) at a distance from the distal end of the gripper shaft (10)
Data Source
AI summary
A gripper system comprises:a gripper shaft;a vacuum source;a first valve arranged between the vacuum source and the suction tube;a liquid reservoir;a source of pressurized gas;a second valve arranged between the source of pressurized gas and the suction tube or the liquid reservoir;a control unit for controlling the first valve and the second valve such that:for picking the ophthalmic lens up, suction is supplied to the suction tube;during transporting the ophthalmic lens, the suction tube is filled with liquid from the liquid supply tube;for releasing the ophthalmic lens from the gripper head, liquid is pressed through the fluid channel and through the suction opening of the gripper head.