Progressive Addition Lens Design Inward Movement Alignment
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Solution Overview
Problem
Existing progressive addition lenses often fail to achieve optimal binocular vision due to discrepancies between the designed and actual inward movement of the line-of-sight, particularly when transitioning from far to near distances, and are affected by the measurement errors caused by the lens meter's diameter, leading to insufficient optical states and impaired vision.
Innovation Solution
A method for designing progressive addition lenses where the amount of design inward movement is set greater than the amount of inward movement of the line-of-sight, with iterative calculations to align the refractive power and astigmatism distributions within the pupil diameter, and considering the lens meter's influence to correct measurement errors, ensuring the optical state is optimized along the principal line of vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amount of design inward movement is set equal to the amount of inward movement of line-of-sight, then the optical state along the principal line of vision is optimized, but measurement errors caused by the lens meter's diameter lead to insufficient optical states and impaired vision
Solution Approach 1:
The patent changes the parameter relationship from equality to inequality, specifically setting the amount of design inward movement greater than the amount of inward movement of line-of-sight. This parameter adjustment compensates for measurement errors and optical state deviations, ensuring that the lens design accounts for the lens meter's diameter limitations and achieves the desired optical performance despite measurement inaccuracies.
2Reliability
If the amount of design inward movement is set greater than the amount of inward movement of line-of-sight, then measurement errors are compensated and optical state is optimized, but the complexity of iterative calculations increases
Solution Approach 1:
The patent implements an iterative calculation process that uses feedback to adjust the amount of design inward movement. By repeatedly calculating and comparing the optical state along the principal line of vision with the desired target state, the system automatically refines the design parameters. This feedback mechanism ensures that the complex iterative calculations converge on the optimal solution that compensates for measurement errors while achieving reliable binocular vision.
3Manufacturing precision
If iterative calculations are performed to align refractive power and astigmatism distributions, then optical performance is accurately aligned along the principal line of vision, but the design process becomes more time-consuming
Solution Approach 1:
The patent performs preliminary actions by pre-calculating and pre-adjusting the refractive power and astigmatism distributions based on the determined amount of design inward movement. By preparing these optical parameters in advance through iterative calculations, the system establishes an optimized optical state along the principal line of vision before final lens manufacturing. This preliminary preparation ensures high manufacturing precision while the iterative process is completed efficiently through automated calculations.
Data Source
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AI summary
An object of the present invention is to improve the optical state of a progressive addition lens along a principal line of vision through which the line-of-sight of a wearer passes by making the displacement of a position at which the optical state on particularly the front near vision becomes the best to be the same as the amount of inward movement of line-of-sight, when the wearer moves his (or her) line-of-sight from the front far distance to the front near distance an expression OI < DH is satisfied when: the principal line of vision L is an intersecting line of the line-of-sight of the wearer of the progressive addition lens from the distance vision to the near vision and a refractive surface of the progressive addition lens; a point F and a point ON in the principal line of vision respectively represent a position corresponding to the front distance vision of the wearer of the progressive addition lens and a position corresponding to the front near vision of the wearer of the progressive addition lens; the amount of inward movement of line-of-sight or represents a displacement of the point ON from the point F toward the nose side in the horizontal direction; a point DN is an intersection of a profile curve in horizontal direction H and a principal meridian curve M, in which the profile curve in horizontal direction H passes through the point ON and the principal meridian curve M passes through the point F of the front distance vision; and an amount of design inward movement DH is a displacement of the point DN from the point F toward the nose side in the horizontal direction.