Stacked Solid-State Imaging Device for Motion Detection
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Solution Overview
Problem
Conventional solid-state imaging devices face challenges in simultaneously achieving high image quality for ordinary imaging and accurate motion detection due to the need for logic circuits that reduce the area of photodiodes, leading to decreased charge signal levels and degraded motion detection accuracy.
Innovation Solution
A solid-state imaging device is designed with a stacked configuration of semiconductor substrates, where ordinary pixels and motion detection pixels are arranged to allow for separate optimization of their areas and circuitry, enabling increased pixel density for ordinary imaging while maintaining large photodiode areas for motion detection, using a combination of reading circuits and amplification circuits to enhance signal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If logic circuits are included in each pixel for motion detection, then motion detection capability is improved, but photodiode area decreases
Solution Approach 1:
The imaging device is divided into two separate pixel arrays: ordinary imaging pixels for capturing static images and motion detection pixels for detecting motion. This segmentation allows each pixel type to be optimized independently, with motion detection pixels having larger photodiode areas for higher sensitivity while ordinary pixels can have smaller areas to increase pixel density.
Solution Approach 2:
The patent transitions from a two-dimensional planar arrangement to a three-dimensional stacked configuration, placing ordinary imaging pixels and motion detection pixels on different substrates stacked in the vertical direction. This dimensional change allows both pixel types to coexist without competing for the same lateral space, resolving the area conflict.
2Quantity of substance
If photodiode area is decreased to accommodate logic circuits, then pixel density increases, but charge signal level decreases
Solution Approach 1:
By segmenting the pixel array into ordinary imaging pixels and motion detection pixels on separate substrates, the patent allows motion detection pixels to maintain large photodiode areas for high charge signal levels while ordinary pixels can be densely packed. The stacking arrangement enables both pixel types to achieve their optimal densities without compromising signal quality.
3Quantity of substance
If photodiode area is decreased, then more pixels can be arranged, but motion detection accuracy decreases
Solution Approach 1:
The patent creates dedicated motion detection pixel regions with larger photodiode areas optimized for motion sensitivity, separate from ordinary imaging pixels. This segmentation ensures that motion detection accuracy is maintained through appropriately sized photodiodes while the overall device can still achieve high pixel density through the stacked configuration.
Solution Approach 2:
By arranging motion detection pixels and ordinary imaging pixels in the vertical stacking direction rather than competing for lateral space, the patent enables both pixel types to maintain their optimal sizes. Motion detection pixels can have larger areas for high accuracy while ordinary pixels can be numerous and dense, without one compromising the other.
4Measurement precision
If amplification circuits are added to maintain charge signal level, then motion detection accuracy is improved, but photodiode area must be further decreased
Solution Approach 1:
By providing dedicated amplification circuits in the signal processing path of motion detection pixels, the patent can maintain large photodiode areas for high sensitivity while compensating for any signal level variations through targeted amplification. This segmentation allows amplification resources to be concentrated where they are most needed for motion detection without affecting ordinary imaging pixels.
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 configuration allows for improved image quality in ordinary imaging and enhanced motion detection accuracy by increasing the number of ordinary pixels and maintaining larger photodiode areas for motion detection pixels, thereby suppressing image quality degradation and accuracy loss.
Implementation Method 1
n first photoelectric conversion devices that are periodically arranged in the first semiconductor substrate, the n first photoelectric conversion devices generating first electric charge signals acquired by performing photoelectric conversion of the incident light
Data Source
AI summary
A solid-state imaging device includes a first semiconductor substrate to which light is incident; a second semiconductor substrate stacked to the first semiconductor substrate; n first photoelectric conversion devices periodically arranged in the first semiconductor substrate and generating first electric charge signals; n first reading circuits arranged in correspondence with the n first photoelectric conversion devices in the first semiconductor substrate, respectively, each of the n first reading circuits accumulating the first electric charge signal outputting a signal voltage corresponding to the accumulated first electric charge signal as a first pixel signal; a driving circuit sequentially outputting the first pixel signal; m second photoelectric conversion devices periodically arranged in one of the first/second semiconductor substrates and generating second electric charge signals; and m second reading circuits sequentially outputting a second pixel signal, wherein m and n are natural numbers equal to 2 or more than 2.