Bi-aspherical Progressive Lens Common Object-Side Surface
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Solution Overview
Problem
The complexity of structuring refractive surfaces and establishing a common base curve in bi-aspherical type progressive-power lenses leads to inefficient production and high costs due to the need for numerous semi-lens designs, particularly when both surfaces must be processed after each order is received.
Innovation Solution
The method involves designing bi-aspherical type progressive-power lenses with a first refractive surface having lateral symmetry about the far vision power measurement position and a second refractive surface with lateral asymmetry, allowing the same object-side surface to be used for multiple addition powers, thereby reducing processing costs and improving efficiency by using a common semi-lens for specific power ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If both surfaces are processed after each order is received, then customization for different addition powers is achieved, but production efficiency decreases and costs increase
Solution Approach 1:
The lens production process is segmented into two distinct phases: pre-processing of the object-side surface (common to multiple addition powers) and post-processing of the eyeball-side surface (customized for specific addition powers). This segmentation allows the object-side surface to be manufactured in advance as a semi-lens, which can then be combined with different eyeball-side surfaces to create customized progressive lenses for various addition powers, thereby improving production efficiency while maintaining customization capability.
Solution Approach 2:
The object-side surface of the lens is pre-processed and prepared as a semi-lens before the final assembly. This preliminary action involves creating a base lens with the correct object-side curvature and progressive power distribution that can serve multiple addition power requirements. By performing this preparation in advance, the manufacturer reduces the processing time and cost for each individual lens order while still achieving the required customization through subsequent eyeball-side surface processing.
2Adaptability or versatility
If numerous semi-lens designs are prepared for different addition powers, then customization capability is improved, but inventory management complexity and costs increase
Solution Approach 1:
A single object-side surface design is created that can serve multiple addition power requirements. This universal object-side surface is engineered with specific curvature characteristics and progressive power distribution that remain optimal across a range of addition powers (0.5 to 3.50 diopters). By making the object-side surface universal rather than customized for each addition power, the system reduces inventory management complexity while maintaining the ability to provide customized lenses for different presbyopia correction needs through variation in the eyeball-side surface.
3Ease of manufacture
If the same object-side surface is used for multiple addition powers, then production cost decreases, but optical precision for specific prescriptions may be compromised
Solution Approach 1:
The lens design applies different quality requirements to different surfaces: the object-side surface is designed with universal characteristics optimized for a range of addition powers, while the eyeball-side surface is customized with specific curvature and power characteristics tailored to each individual prescription. This local differentiation allows the object-side surface to be manufactured once and reused, reducing production costs, while the eyeball-side surface maintains the necessary optical precision for each specific prescription through customized processing.
Data Source
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AI summary
There is provided a group of bi-aspherical type progressive-power lenses for which the processing costs are reduced. In a bi-aspherical type progressive-power lens (es), the relationships DHf + DHn < DVf + DVn and DHn < DVn or further, DVn - DVf > ADD/2 and DHn - DHf < ADD/2 are satisfied; DHf and DVf are designated respectively as a surface refractive power in a horizontal direction and a surface refractive power in a vertical direction at a far vision power measurement position F1 on a first refractive surface that acts as an object-side surface; with DHn and DVn are designated respectively as a surface refractive power in a horizontal direction and a surface refractive power in a vertical direction at a near vision power measurement position N1 on the first refractive surface; a surface astigmatism component at F1 and N1 of the first refractive surface is canceled by a second refractive surface of the eye-side surface; and the first and second refractive surfaces are combined to provide a far vision power (Df) and an addition (ADD) on the basis of a prescription; wherein the same first refractive surface is used for at least two or more kinds of different addition power.