Electrochromic Control Circuit Maintains Light Transmittance
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Solution Overview
Problem
Electrochromic devices face challenges in maintaining light transmittance and requiring rapid switching between colored and bleached states, especially when used in applications like vehicle glass where good transmittance is essential, and existing technologies are inefficient in controlling ion movement and coloration time.
Innovation Solution
A control circuit and method utilizing a DC pulse voltage source to manage the electrochromic device's coloration and bleaching processes through a color switch and voltage detecting units, ensuring the electrochromic device remains within a preset color-depth range by monitoring current and voltage levels to maintain light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If voltage is applied continuously to achieve light shielding, then light shielding property is improved, but light transmittance deteriorates
Solution Approach 1:
The patent applies periodic pulsed voltage instead of continuous voltage to the electrochromic device. The control circuit delivers voltage pulses with specific duty cycles and frequencies that induce sufficient coloration for light shielding while allowing partial recovery of transmittance during pulse off-periods, thereby achieving both light shielding and transmittance maintenance
2Manufacturing precision
If voltage is applied longer to increase coloration, then coloration depth is improved, but response time deteriorates
Solution Approach 1:
The control circuit employs periodic pulsed voltage delivery with optimized pulse width and frequency. This periodic action achieves target coloration depth faster by delivering concentrated voltage bursts rather than prolonged low-level voltage, significantly reducing the overall coloration response time while maintaining desired coloration depth
Solution Approach 2:
The system applies preliminary high-intensity voltage pulses to rapidly initiate and accelerate the coloration process before transitioning to maintenance-mode pulsing. This preliminary action jump-starts the electrochemical reactions, reducing the time required to reach target coloration depth
3Productivity
If ion transfer is increased to enhance coloration efficiency, then coloring efficiency is improved, but light transmittance deteriorates
Solution Approach 1:
The periodic pulsed voltage delivery allows ion transfer to occur intensively during pulse on-periods (enhancing coloring efficiency) while providing recovery periods during pulse off-periods when ions can partially diffuse back, preventing excessive ion accumulation that would cause permanent transmittance loss. This temporal separation decouples coloring efficiency from transmittance degradation
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
The solution enables efficient control of light transmittance and coloration time, preventing deepening of the colored state and maintaining optimal light transmittance by regulating the power supply based on detected current and voltage levels, thereby improving the electrochromic device's performance.
Implementation Method 1
Electrochromic materials have the property of color changing due to electrochemical redox reactions. They are transformed in a different charged state to obtain a different color. Thus the optical properties (color or transmittance) of the electrochromic device can be adjusted by the voltage applied.
Implementation Method 2
When the external voltage is off, ions are diffused slowly away from the active electrochromic layer. Thus the electrochromic device is switched to a bleached state.
Data Source
AI summary
A control circuit and a method for maintaining light transmittance of an electrochromic device are revealed. An input power source is turned off once a current input into an electrochromic device is decreased to a preset value. Then a voltage between two electrodes of the electrochromic device is detected. When the voltage between two electrodes of the electrochromic device is dropped to a preset value, the input power source is restored. According to the above steps, the coloration of the electrochromic device is maintained within a preset range. Thus light transmittance of the electrochromic device is kept at a certain range.