Electrochromic Shutter for Photodiode Protection
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Solution Overview
Problem
Integrated photosensitive elements, such as photodiodes, degrade due to prolonged exposure to visible radiation, leading to reduced sensitivity and effectiveness, as they continuously detect light without a mechanical shutter mechanism, necessitating a solution to limit exposure during setup phases while maintaining functionality.
Innovation Solution
An integrated circuit with an electrooptic system that filters specific wavelengths of visible light using materials like tungsten oxide and hydrated tantalum oxide, allowing electrical control of transmission coefficients to reduce degradation during setup and enable recording without additional color filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the photosensitive element continuously detects light without a shutter mechanism, then the image can be detected outside recording periods and adjustments can be made while displaying the detected image, but the photosensitive element degrades due to prolonged exposure to light
Solution Approach 1:
The patent replaces the mechanical shutter system with an electrochromic system that uses electrical signals to control light transmission. The electrochromic layer changes its optical properties (from transparent to absorbing) in response to electrical control signals, eliminating the need for mechanical moving parts while achieving the same protective function.
Solution Approach 2:
The patent changes the optical transmission parameter of the electrochromic layer dynamically. By controlling the transmission coefficient between two states (transparent state allowing full light passage and absorbing state blocking specific wavelengths), the system adjusts the amount of light reaching the photosensitive element based on operational requirements.
2Reliability
If a mechanical shutter is used to limit light exposure during setup phases, then photodiode degradation is reduced, but the image cannot be detected outside recording periods and adjustments cannot be made while displaying
Solution Approach 1:
The patent implements a dynamic light control system where the electrochromic layer can rapidly switch between transparent and absorbing states in response to control signals. This dynamic responsiveness allows the system to adapt light transmission in real-time, enabling continuous image detection during setup while protecting the photodiode during recording phases.
Solution Approach 2:
The patent replaces the mechanical shutter system with an electrochromic system that uses electrical signals to control light transmission. The electrochromic layer changes its optical properties (from transparent to absorbing) in response to electrical control signals, eliminating the need for mechanical moving parts while achieving the same protective function.
3Reliability
If the electrooptic system filters out more wavelengths of visible light, then photodiode degradation is reduced, but the image detection capability and color accuracy may be compromised
Solution Approach 1:
The patent applies selective filtering by wavelength rather than uniform filtering across all wavelengths. The electrochromic layer is designed to absorb specific wavelength ranges (particularly those causing degradation) while allowing other wavelengths to pass through, preserving color information and image quality while protecting the photodiode.
Solution Approach 2:
The patent changes the optical transmission parameter of the electrochromic layer dynamically. By controlling the transmission coefficient between two states (transparent state allowing full light passage and absorbing state blocking specific wavelengths), the system adjusts the amount of light reaching the photosensitive element based on operational requirements.
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 electrooptic system effectively filters over 80% of the visible spectrum, particularly the red-orange range, reducing photodiode degradation, allowing continuous image detection with minimal impairment during setup and full spectrum recording, thus extending the lifespan of the photosensitive elements.
Implementation Method 1
The electrooptic system is located in the path of at least one light ray capable of reaching the photosensitive element and possesses at least one optical property that may be modified by an electrical control signal. The modified optical property of the electrooptic system is advantageously the transmission coefficient.
Implementation Method 2
In the other state, the electrooptic system absorbs or reflects all or part of the wavelength range in question so as to limit the degradation of the photosensitive element.
Implementation Method 3
photons reaching a photodiode normally create electron-hole pairs generating an electrical current proportional to the number of photons received by the photodiode
Data Source
AI summary
An integrated circuit includes at least one photosensitive element capable of delivering an electrical signal when light of at least one wavelength of the visible spectrum reaches it, and an electrooptic system functioning as an electrochemical shutter. The electrooptic system is located in the path of at least one light ray capable of reaching the photosensitive element and possesses at least one optical property, dependent on electrochemical reaction, that can be modified by an electrical control signal. The optical property is preferably transmission.