Progressive Lens Base Curve Selection for Thickness Reduction
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Solution Overview
Problem
Conventional methods for manufacturing progressive refractive lenses often result in an unnecessary increase in base curve and thickness due to selecting a semi-finish lens based on a common base curve for multiple lenses, leading to suboptimal designability and wearing comfort, especially when manufacturing lenses with varying near vision powers.
Innovation Solution
The method involves selecting a base curve based on the near vision power by adding the addition power to the far vision power, allowing for the selection of a semi-finish lens with a base curve that is not necessarily larger than usual, thereby reducing the thickness of the progressive refractive lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a common base curve is selected for multiple progressive lenses with different near vision powers, then the manufacturing process is simplified, but the lens thickness and designability deteriorate
Solution Approach 1:
The patent applies parameter changes by selecting base curves based on near vision power values. Different base curve parameters are chosen according to the specific near vision power requirements, allowing optimization of lens thickness while maintaining manufacturing feasibility. The manufacturing system changes the base curve parameter selection criterion from a common fixed value to a variable determined by the near vision power specification.
2Manufacturing precision
If a larger base curve is selected to accommodate high addition power lenses, then the addition power requirement is met, but the lens thickness and wearing comfort deteriorate
Solution Approach 1:
The patent resolves this contradiction by changing the base curve parameter selection based on near vision power. Instead of using a fixed large base curve for all high addition power lenses, the system selects appropriate base curve parameters matched to the specific near vision power requirements, thereby achieving accurate addition power while minimizing lens thickness.
Solution Approach 2:
The patent applies local quality by matching specific base curve characteristics to specific near vision power requirements. Each lens receives a base curve optimized for its local optical requirements rather than a universal base curve, allowing precise control over lens thickness and optical performance for each individual prescription.
3Device complexity
If one semi-finish lens type is used for all progressive lenses, then inventory management is simplified, but lens designability and optimal fit deteriorate
Solution Approach 1:
The patent applies parameter changes by introducing near vision power-based base curve selection. This creates multiple semi-finish lens types differentiated by base curve parameters corresponding to different near vision power ranges, enabling optimized lens design while maintaining a structured inventory system organized by optical parameters.
Data Source
Figure 1(a)~1(c)
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AI summary
Provided is a manufacturing method of a progressive refractive lens including a first surface being an object side surface; a second surface being an eyeball side surface; a far vision part for viewing a far vision; a near vision part for viewing a near vision; and a progressive part for viewing an intermediate vision provided between the far vision part and the near vision part, the method including: selecting a base curve according to a near vision power in the near vision part; selecting a semi-finish lens having the base curve; and forming a surface having a progressive refractive power by processing the semi-finish lens, wherein the near vision power is obtained by adding an addition power in the progressive refractive lens to a far vision power in the far vision part.