Solid-State Imaging Device Dual-Readout Signal Processing
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Solution Overview
Problem
In solid-state imaging devices, the difference in charge accumulation time between pixel rows for focus detection and image formation can lead to deteriorated image quality due to varying charge accumulation times, affecting the acquisition of both focus detection and image forming signals.
Innovation Solution
The implementation of a dual-readout operation in the analog-to-digital conversion process, where both focus detection and image forming signals are processed simultaneously, reducing the charge accumulation time disparity between pixel rows and enhancing image quality by ensuring consistent signal output across all pixel rows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pixels for phase difference focus detection are arranged in a solid-state imaging device, then focus detection signal and image forming signal can be acquired, but luminance differences between pixel rows occur due to varying charge accumulation times
Solution Approach 1:
The pixel array is divided into different pixel types (first pixels with first photoelectric conversion portions and second pixels with second photoelectric conversion portions) arranged in alternating rows. This segmentation allows different charge accumulation times for different pixel types, enabling phase difference focus detection while maintaining luminance uniformity through differential reading operations.
Solution Approach 2:
The solid-state imaging device performs periodic reading operations where odd-numbered pixel rows are read at a first timing and even-numbered pixel rows are read at a second timing. This periodic alternating reading pattern compensates for charge accumulation time differences between pixel types, eliminating luminance differences between rows while preserving focus detection capability.
2Manufacturing precision
If dual-readout operation is implemented to reduce charge accumulation time disparity, then image quality improves, but circuit complexity increases
Solution Approach 1:
The memory unit and output signal lines are designed to handle multiple signal types (first digital signals from first photoelectric conversion portions, second digital signals from second photoelectric conversion portions, and summed signals) through a unified dual-readout architecture. This multi-functional design improves image quality by reducing charge accumulation disparities while optimizing circuit scale through shared resources.
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 improves image quality by minimizing luminance differences between pixel rows, resulting in a smoother and more consistent image output, while also optimizing digital signal transfer and restricting circuit scale growth.
Implementation Method 1
each of the pixels having a first photoelectric conversion portion and a second photoelectric conversion portion
Data Source
AI summary
A solid-state imaging device in which a signal from a first photoelectric conversion portion of one pixel, signals from the first photoelectric conversion portion and a second photoelectric conversion portion of the one pixel, and a noise signal from the one pixel are converted into a first digital signal, a second digital signal, and a third digital signal, respectively. As signals of pixels in a first pixel row, the first, the second, and the third digital signals are input from a memory unit to output signal lines. As signals of pixels in a second pixel row adjacent to the first pixel row of a pixel unit in the row direction, the second and the third digital signals are input from the memory unit to the output signal lines while the first digital signal is not output.