Progressive Lens Light Guide Optical System Calculation
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Solution Overview
Problem
Existing progressive ophthalmic lenses fail to provide both suitable ophthalmic and supplementary visions simultaneously without causing visual fatigue, as they do not optimize the optical system to match the wearer's residual accommodative effort between the corrected ophthalmic vision and supplementary image.
Innovation Solution
A method for calculating an optical system of a progressive addition ophthalmic lens with an embedded light guide optical element, optimizing the system to ensure the accommodation effort for both visions is less than or equal to the wearer's residual accommodative effort, by defining the exit surface's angular aperture contour and calculating the average sphere values of the front and back surfaces to meet specific equation requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If progressive addition lenses provide both ophthalmic vision and supplementary vision, then the lens functionality is improved, but visual fatigue occurs due to excessive accommodation effort
Solution Approach 1:
The patent applies parameter changes by optimizing the optical system parameters (front surface average sphere value, back surface power distribution) to ensure that the accommodation effort required for both ophthalmic and supplementary vision remains within the wearer's residual accommodative effort. This resolves the contradiction by adjusting system parameters to simultaneously provide dual functionality while preventing visual fatigue.
Solution Approach 2:
The patent implements preliminary action by calculating and optimizing the optical system design before manufacturing, taking into account the wearer's residual accommodative effort. The optimization process预先 determines the appropriate average sphere value and power distribution to prevent excessive accommodation effort from the outset, thereby avoiding visual fatigue while providing both vision types.
2Ease of operation
If the optical system is optimized to match residual accommodative effort, then visual comfort is improved, but the calculation complexity increases
Solution Approach 1:
The patent transforms the complex optimization problem into a manageable calculation by focusing on key parameters: the front surface average sphere value and back surface power distribution. By expressing the solution in terms of these specific parameters and using the formula D_FS(α,β) = (Pprox - POT(α,β)) / (ELD + 0.01745·α), the patent reduces calculation complexity while maintaining visual comfort optimization.
Solution Approach 2:
The patent replaces complex iterative optimization mechanisms with a direct calculation approach. Instead of using complex numerical optimization algorithms, the patent uses analytical formulas to directly compute the required front surface average sphere value based on the wearer's prescription data and residual accommodative effort, thereby simplifying the calculation process.
3Adaptability or versatility
If the light guide optical element is embedded in the lens, then supplementary image output is achieved, but the lens structure becomes more complex
Solution Approach 1:
The patent applies the nesting principle by embedding the light guide optical element within the progressive addition lens structure. The light guide element is integrated into the lens body, with its exit surface positioned at the front surface of the lens. This nested configuration allows the lens to provide both ophthalmic vision through the progressive addition design and supplementary vision through the embedded light guide element, achieving dual functionality without requiring separate components.
Solution Approach 2:
The patent implements multi-functionality by designing the lens to simultaneously provide ophthalmic vision correction through the progressive addition optical system and supplementary vision through the embedded light guide optical element. The front surface of the lens serves dual purposes: it is part of the progressive addition optical system for ophthalmic vision and also serves as the exit surface for the light guide element for supplementary image output.
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
Enables comfortable viewing of scenes and supplementary images without generating visual fatigue, allowing simultaneous or alternate availability of ophthalmic and supplementary visions, with the optical system designed to match the wearer's residual accommodative effort.
Implementation Method 1
light beams are reflected a plurality of times between two 'reflection' faces between being introduced into the spectacle lens and exiting therefrom, said two reflection faces being faces of the light-guide optical element
Implementation Method 2
progressive addition ophthalmic lens... arranged to deliver a corrected ophthalmic vision image to the wearer through the back surface
Data Source
Figure 1a~1b
AI summary
A progressive ophthalmic spectacle lens (10) capable of correcting a wearer's ophthalmic vision and having a back surface (BS) and a front surface (FS), said lens comprising a light guide optical element arranged to output a supplementary image (SI) to the wearer through an exit surface (ES) of said light guide optical element, where the exit surface (ES), the back surface (BS) and an optical material located between said exit surface (ES) and said back surface (BS) form an optical device (OD) and wherein said optical device (OD) comprises an area of stabilized optical power.