Imaging Device Voltage Supply Circuit Resolves After-Image
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Solution Overview
Problem
Existing imaging devices with organic photoelectric conversion layers suffer from high-luminance after-image issues due to residual charge, which is not effectively addressed by avoiding wire placement below pixel electrode gaps, limiting design flexibility and incomplete signal charge collection.
Innovation Solution
An imaging device with a voltage supply circuit that applies specific voltage periods to electrodes, including a moment where the potential difference between electrodes is zero, facilitating recombination of signal charge carriers and reducing high-luminance after-image occurrence while maintaining design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wires are arranged immediately below the gaps between pixel electrodes, then device complexity is reduced and manufacturing is simplified, but high-luminance after-image occurs due to residual charge accumulation
Solution Approach 1:
The patent applies preliminary action by introducing a reset period before the accumulation period during which residual charge is actively removed from the organic photoelectric conversion layer. This preliminary charge removal action prevents the formation of after-image while maintaining simple wire arrangement below pixel electrode gaps. The reset circuit performs the preparatory action of clearing residual charge before signal accumulation begins.
Solution Approach 2:
The patent implements periodic action by dividing the operating cycle into distinct accumulation periods and reset periods. During accumulation periods, signal charge is collected; during reset periods, residual charge is removed through reversed electric field application. This periodic switching between charge accumulation and charge removal phases eliminates after-image while preserving the simplified wire layout structure.
2Object-affected harmful factors
If wires are not arranged immediately below the gaps between pixel electrodes, then high-luminance after-image is reduced, but device complexity increases and design flexibility is limited
Solution Approach 1:
The patent replaces the mechanical/structural solution (rearranging wire positions) with an electrical/control solution (applying reset voltages during specific periods). Instead of modifying the physical wire layout to prevent after-image, the invention uses electrical fields applied during reset periods to remove residual charge, thereby eliminating after-image while maintaining the original simple wire arrangement.
3Measurement precision
If accumulation period is extended to collect more signal charge, then measurement precision is improved, but residual charge accumulates causing after-image
Solution Approach 1:
The patent uses periodic action by implementing regular reset periods interspersed between accumulation periods. Even as accumulation period duration is extended to improve signal charge collection and measurement precision, the periodic reset periods systematically remove residual charge buildup, preventing after-image formation while allowing longer accumulation times for better signal detection.
Solution Approach 2:
The patent maintains continuity of useful action by ensuring that while signal accumulation occurs during accumulation periods, charge removal occurs continuously during reset periods. This continuous alternation ensures that residual charge is constantly managed, allowing extended accumulation times for improved measurement precision without compromising signal quality due to after-image effects.
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 effectively reduces high-luminance after-image occurrence while allowing for flexible wire arrangement, enhancing the imaging device's speed and performance by ensuring complete signal charge collection and minimizing residual charge.
Implementation Method 1
a first photoelectric conversion layer between the first electrode and the second electrode, the first photoelectric conversion layer generating first signal charge
Implementation Method 2
the voltage supply circuit supplies a first voltage to the second electrode in a first period when the first unit pixel cell accumulates the first signal charge, a voltage of the second electrode on the basis of a voltage of the first electrode being positive in the first period
Data Source
AI summary
An imaging device having unit pixel cells including a first unit pixel cell, the first unit pixel cell including a first electrode, a second electrode, a first photoelectric conversion layer for generating a first signal charge, and a first signal detection circuit connected to the first electrode for detecting the first signal charge. The imaging device further includes a voltage supply circuit which supplies a first voltage to the second electrode in a first period when the first unit pixel cell accumulates the first signal charge, a voltage of the second electrode on the basis of a voltage of the first electrode being positive in the first period, and the voltage supply circuit supplies a second voltage to at least one of the first electrode and the second electrode in a second period, the second period including a third period when a voltage of the second electrode is negative.