Spectacle Lens Blank Segmentation for Vision Correction
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Solution Overview
Problem
The existing methods for manufacturing spectacle glasses from prefabricated blanks result in significant waste, high labor costs, and inefficiencies due to the need for multiple blanks and extensive machining, which do not adequately correct vision defects across various distances and angles.
Innovation Solution
A method involving prefabricated blanks made of plastic or silicate glass where the front side is not finished and the back side is machined using CNC technology to create prescription lenses, allowing for the production of two spectacle glasses from a single blank with optimized focal points for each eye, reducing waste and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple prefabricated blanks are used to manufacture spectacle glasses with different focal points, then vision correction quality is improved, but material waste and production costs increase
Solution Approach 1:
The blank is segmented into two separate spectacle lenses through CNC machining, allowing two pairs of glasses to be produced from one blank. The blank is positioned and machined to create first and second spectacle lenses with different focal points, effectively dividing the material resource to reduce waste while maintaining optical quality
Solution Approach 2:
A single blank serves multiple functions by being machined to produce two different spectacle lenses with different optical prescriptions. The same blank material is utilized to create lenses for different vision correction needs, increasing material utilization efficiency while maintaining the required optical performance
2Reliability
If extensive CNC machining is performed on blanks to create customized focal points, then individual vision correction is improved, but production time and labor costs increase
Solution Approach 1:
The blanks are prefabricated with preliminary spherical or aspherical surfaces that provide a good starting geometry for CNC machining. This preliminary shaping reduces the amount of material removal and machining time required to achieve the final customized focal points, thereby maintaining individual vision correction quality while improving production efficiency
Solution Approach 2:
The invention changes the focal point parameters of the lenses through CNC machining to match individual vision correction requirements. By programmatically adjusting the surface curvature and focal characteristics during machining, customized optical performance is achieved efficiently without excessive manual intervention
3Ease of manufacture
If standardized spherical blanks are used, then production economy is improved, but visual acuity across different distances and angles deteriorates
Solution Approach 1:
The invention transitions from standardized spherical blanks to asymmetric freeform surfaces through CNC machining. The lenses are machined with non-symmetric curvature distributions that optimize visual acuity across different viewing distances and angles while starting from simple spherical or aspherical blanks, thus maintaining production economy while achieving superior optical performance
Solution Approach 2:
The lens surfaces are designed with dynamic curvature variations that adapt to different viewing conditions. The freeform surfaces created by CNC machining provide continuously varying curvature across the lens surface, enabling optimal focus for near, intermediate, and distant vision as well as peripheral viewing angles
Data Source
AI summary
A method for manufacture of spectacle glasses from prefabricated blanks made without cutting. Each prefabricated blank has a front side not to be finished and an opposite back side. The front side and the back side have at least one optical focus in common. The method includes finishing the back side by calculating a prescription surface based on a prescription of a person. The prescription describes the vision defects of a left and a right eye of the person. The machined back side and the front side together form a first prescription lens and a second prescription lens. The method further includes making first and second spectacle glasses from the first and second prescription lenses. Focal points of the first spectacle glass correct the vision defect of the left eye and focal points of the second spectacle glass correct the vision defect of the right eye of the person.