Electrochromic Element Resistance Ratio for Apodization
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Solution Overview
Problem
Conventional electrochromic (EC) elements face challenges in achieving a suitable transmittance distribution due to insufficient configuration settings, which depend on the resistance ratio of the electrode and electrochromic layer, making it difficult to realize optimal transmittance in solution-type EC elements for applications like apodization filters.
Innovation Solution
The EC element is designed with a specific resistance ratio between the electrodes and the electrochromic layer, determined by the sheet resistance of the electrodes, the diameter of the light modulating region, and the resistivity of the electrochromic layer, allowing for a controlled transmittance distribution that can follow the aperture diameter of a mechanical diaphragm, thereby optimizing the apodization effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the resistance ratio of the electrode and electrochromic layer is not properly controlled, then the transmittance distribution cannot be optimized, but defining specific configuration requirements increases device complexity
Solution Approach 1:
The patent applies parameter changes by establishing specific quantitative relationships between electrode sheet resistance, light modulating region diameter, electrochromic layer resistivity, and electrode resistance to achieve optimal transmittance distribution. The key parameter is the resistance ratio (r/R) which must satisfy equation (1): r/R = (rs × L²)/(ρ × d) × k, where k is a constant between 2-20. This parameter-based approach transforms the qualitative problem of transmittance optimization into a quantitative design criterion.
Solution Approach 2:
The patent applies local quality by differentiating the resistance characteristics between the electrode and electrochromic layer at different spatial scales. The electrode resistance r is calculated based on its sheet resistance rs and the light modulating region diameter L, while the electrochromic layer resistance R depends on its resistivity ρ and thickness d. This local differentiation of resistance properties enables precise control of the transmittance distribution pattern.
2Manufacturing precision
If power is supplied from the outer periphery of the light modulating region, then the transmittance distribution can be controlled, but the voltage drop from outer peripheral portion toward center cannot be adequately optimized
Solution Approach 1:
The patent applies parameter changes by establishing specific quantitative relationships between electrode sheet resistance, light modulating region diameter, electrochromic layer resistivity, and electrode resistance to achieve optimal transmittance distribution. The key parameter is the resistance ratio (r/R) which must satisfy equation (1): r/R = (rs × L²)/(ρ × d) × k, where k is a constant between 2-20. This parameter-based approach transforms the qualitative problem of transmittance optimization into a quantitative design criterion.
Solution Approach 2:
The patent applies equipotentiality by designing the electrode resistance characteristics to compensate for the voltage drop that occurs when power is supplied from the outer periphery. By controlling the resistance ratio and electrode configuration, the system creates an effective equipotential distribution that ensures uniform voltage application across the electrochromic layer, enabling the desired transmittance distribution pattern.
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
This approach enables the realization of a suitable transmittance distribution in EC elements, enhancing their performance as variable apodization filters and improving the optical characteristics of lens units and imaging apparatuses.
Implementation Method 1
An electrochromic (hereinafter, 'electrochromic' may be referred to as 'EC') element is an optical element including a pair of electrodes and an EC layer disposed between the electrodes, wherein a voltage is applied between the pair of electrodes to oxidize or reduce a compound in the EC layer, thereby adjusting the hue or quantity of light in the visible light band.
Implementation Method 2
a voltage is applied between the pair of electrodes to oxidize or reduce a compound in the EC layer
Implementation Method 3
a voltage is applied between the pair of electrodes to oxidize or reduce a compound in the EC layer
Data Source
AI summary
In an electrochromic element including a pair of electrodes and an electrochromic layer disposed between the pair of electrodes, a shape of a light modulating region viewed from a normal direction of the electrode being circular, when a sheet resistance of the electrode is rs (Ω), a resistance of the electrode is r (Ω), a diameter of the light modulating region is L [m], a distance between the pair of electrodes is d (m), the resistivity of the electrochromic layer is ρ (Ω), and a resistance of the electrochromic layer is R (Ω), a resistance ratio (r/R) between the electrode and the electrochromic layer, as shown by r/R=(rsL2)/(ρd), is 2 or more and 20 or less.