Solid-State Imaging Device Leakage Light Correction
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Solution Overview
Problem
In CMOS solid-state imaging devices, leakage light causes noise charges that degrade image quality, leading to a decrease in spatial resolution and sensitivity when half of the pixels are set as effective pixels and the other half as reference pixels for noise correction.
Innovation Solution
A solid-state imaging device employs a signal processing unit that reads pixel signals in two modes: a line thinning-out mode and a line non-thinning-out mode, where the signals from the thinning-out mode are used to correct pixel signals from the non-thinning-out mode, without reducing spatial resolution, by adjusting the line thinning-out rate based on exposure time and performing correction processing for each color component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If half of the pixels are set as reference pixels for noise correction, then the correction for leakage light influence is improved, but the spatial resolution and sensitivity decrease
Solution Approach 1:
The patent dynamically adjusts the reading mode based on imaging conditions. The signal processing unit determines whether to read pixel signals in a first mode (using reference pixels for correction) or a second mode (including all pixels) based on factors such as exposure time and light conditions, thereby optimizing both correction precision and spatial resolution adaptively
Solution Approach 2:
The patent changes the reading parameters of pixel signals based on imaging conditions. By adjusting the reading mode (first mode with line thinning-out for correction vs. second mode including all lines for full resolution), the system optimizes the balance between correction effectiveness and image quality without permanently sacrificing spatial resolution
2Productivity
If pixel signals are read in line thinning-out mode for correction, then the correction processing efficiency is improved, but the spatial resolution decreases
Solution Approach 1:
The patent segments the pixel signal reading process into two distinct modes: a first mode that reads only specific lines (thinning-out) for efficient correction processing, and a second mode that reads all lines for full spatial resolution. This segmentation allows each mode to serve its specific purpose optimally without compromising the other
Solution Approach 2:
The patent adds a temporal dimension to the reading process by sequentially performing readings in different modes. The signal processing unit first reads in the first mode for correction, then reads in the second mode for full resolution output, thereby resolving the spatial resolution loss through time-based multi-mode operation
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 corrects the influence of leakage light on image quality without decreasing spatial resolution or sensitivity, improving image fidelity by reducing noise components in the pixel signals.
Implementation Method 1
a photoelectric conversion unit that generates electric charge in accordance with received light
Data Source
AI summary
In a pixel array unit 11, pixels that generate pixel signals are arranged in a matrix. A control unit 17 performs reading of pixel signals in a first mode in which reading of the pixel signals is performed by thinning out lines from the pixel array unit 11, and reading of pixel signals in a second mode in which reading of the pixel signals is performed by including the lines thinned out in the first mode after the reading in the first mode. A signal processing unit 16 uses a pixel signal read in the first mode and a pixel signal read in the second mode, to set an amount of correction for a pixel of the lines thinned out in the first mode, on the basis of the pixel signal read in the second mode from a pixel in which reading of the pixel signal is performed in the first mode and the second mode, and corrects the pixel signal read in the second mode from the pixel of the lines thinned out in the first mode with the set amount of correction to reduce an influence of leakage light.