Imaging Element Reset Signal Intermediate Voltage Noise Control
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Solution Overview
Problem
Conventional imaging technologies experience image quality deterioration due to noise generated when the reset transistor is switched from on to off during shutter operations, causing variations in charge holding unit voltages and affecting image quality.
Innovation Solution
An imaging element and method that involves reading signals in specific states of the reset transistor, using correlated double sampling to generate noise and data signals, and setting the reset signal to an intermediate voltage before switching from on to off, with control units managing these processes to minimize charge movement and voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reset transistor is switched from on to off during shutter operation, then the reset function is achieved, but noise is generated and image quality deteriorates due to charge movement and voltage variation in the charge holding unit
Solution Approach 1:
The patent applies preliminary action by setting the reset signal to an intermediate voltage level before switching it from on to off. This intermediate state is established in advance to prevent excessive charge movement in the channel unit, thereby avoiding voltage variations in the charge holding unit and reducing noise generation during the reset transition
Solution Approach 2:
The patent changes the voltage parameter of the reset signal by introducing an intermediate voltage level between the on and off states. This parameter modification controls the charge movement amount in the reset transistor channel, preventing large voltage swings in the charge holding unit and thereby reducing noise while maintaining the reset function
2Object-affected harmful factors
If correlated double sampling is used to remove kTC noise, then noise reduction is achieved, but the complexity of signal processing increases
Solution Approach 1:
The patent employs feedback mechanisms through correlated double sampling, where previously sampled signals are fed back and subtracted from current signals. This process effectively removes kTC noise by canceling out correlated noise components while preserving the actual image signal, achieving noise reduction through systematic feedback processing
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 effectively prevents image quality deterioration by reducing noise and charge variations, improving the overall image quality by setting the reset signal to an intermediate voltage and controlling transition times based on noise and data signal comparisons.
Implementation Method 1
a photoelectric conversion unit that photoelectrically converts incident light
Data Source
AI summary
The present technology relates to an imaging element, a driving method of an imaging element, and an electronic device capable of preventing deterioration in image quality. The imaging element reads a first signal in a state where a charge holding unit is reset, reads a second signal in a state where a reset transistor is turned off, reads a third signal in a state where charges obtained by photoelectric conversion are accumulated in the charge holding unit, reads a fourth signal in a state where the charge holding unit is reset, and sets a reset signal to an intermediate voltage between an on voltage and an off voltage before the reset signal to a gate electrode of the reset transistor is switched from the on voltage to the off voltage after the first signal is read, and generates a noise signal by correlated double sampling of the first signal and the second signal, generates a data signal by correlated double sampling of the third signal and the fourth signal, and generates an output signal by correlated double sampling of the data signal and the noise signal. The present technology is applied to, for example, an imaging element.