Transfer Transistor Charge Separation for Flicker Noise Reduction
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Solution Overview
Problem
Existing photoelectric conversion apparatuses experience signal noise due to false signals generated by the transfer transistor during intermittent exposure, leading to deteriorated signal quality when capturing images of light-emitting devices with repetitive brightness variations.
Innovation Solution
A photoelectric conversion apparatus with a transfer transistor that performs on-off operations in two states - one where the charge accumulation unit is accumulating charges and another where it is not - to separate and remove false signal components, allowing for high-quality signal acquisition during intermittent exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transfer transistor is operated a plurality of times during intermittent exposure, then exposure signals can be accumulated in the charge accumulation unit, but false signals are added and signal noise characteristics deteriorate
Solution Approach 1:
The patent segments the signal accumulation process into two distinct parts: (1) accumulation of photoelectric conversion signals during exposure periods, and (2) accumulation of false signals during non-exposure periods. By separating these two signal types and processing them differently, the system can accumulate multiple exposure signals to improve productivity while removing false signals to maintain reliability.
Solution Approach 2:
The patent extracts and removes false signal components from the accumulated signal. The charge accumulation unit selectively accumulates only the valid photoelectric conversion signals while excluding the false signals generated by transfer transistor operations. This extraction principle allows the system to maintain high signal quality even during multiple intermittent exposures.
2Object-affected harmful factors
If intermittent exposure is performed a plurality of times during an exposure period, then flicker phenomenon can be suppressed, but false signals from transfer transistor operations are added to the charge accumulation unit
Solution Approach 1:
The patent converts the harmful false signals into a removable component. By recognizing that false signals are generated consistently during non-exposure periods, the system can accumulate these false signals separately and then subtract them from the total accumulated signal, thereby eliminating their harmful effect while preserving the beneficial flicker suppression from intermittent exposure.
Solution Approach 2:
The patent performs preliminary accumulation of false signals during non-exposure periods before the final image processing. By accumulating false signals in advance during periods when no light is incident on the photoelectric conversion unit, the system prepares the false signal component for subsequent removal, enabling clean signal extraction without affecting the flicker suppression benefit.
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 acquisition of high-quality signals by isolating and removing false signal components, thereby improving signal noise characteristics and maintaining image quality during intermittent exposure.
Implementation Method 1
a photoelectric conversion unit which converts incident light into a charge
Data Source
AI summary
A photoelectric conversion apparatus, comprising: a photoelectric conversion unit; a charge accumulation unit configured to accumulate charges generated in the photoelectric conversion unit; and a transfer transistor configured to connect the photoelectric conversion unit and the charge accumulation unit to each other and to perform a transfer operation of a charge from the photoelectric conversion unit to the charge accumulation unit, wherein the photoelectric conversion apparatus outputs: a first signal obtained by performing an on-off operation of the transfer transistor a plurality of times in a state where the charge accumulation unit is accumulating charges; and a second signal obtained by performing an on-off operation of the transfer transistor a plurality of times in a state where the charge accumulation unit is not accumulating charges.