Solid-State Imaging Device Multi-Direction Phase Detection
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Solution Overview
Problem
Existing solid-state imaging devices face a reduction in framerate and spatial resolution of phase difference information due to the method of selecting vertical or horizontal line detection on a row-by-row basis, leading to decreased accuracy in focus position adjustment.
Innovation Solution
A solid-state imaging device with a plurality of pixels arranged in rows and columns, featuring multiple photoelectric converters and a micro lens, where the readout circuit performs multiple readout operations to combine signals from these converters, allowing for phase difference calculation in multiple directions, thereby improving spatial resolution and maintaining framerate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If vertical or horizontal line detection is selected on a row-by-row basis, then the framerate is maintained, but the spatial resolution of phase difference information decreases
Solution Approach 1:
The pixel array is segmented into multiple independent photoelectric converters (first, second, third, and fourth converters) within each pixel, allowing simultaneous phase difference detection in multiple directions. This segmentation enables the system to maintain high framerate while improving spatial resolution by processing multiple detection directions in parallel rather than sequentially.
Solution Approach 2:
The invention transitions from single-direction phase difference detection to multi-directional detection by arranging photoelectric converters in both vertical and horizontal directions within each pixel. This dimensional expansion allows the system to capture phase difference information in multiple spatial dimensions simultaneously, resolving the contradiction between framerate and spatial resolution.
2Measurement precision
If multiple readout operations are performed to read charges from all photoelectric converters, then the spatial resolution of phase difference information improves, but the framerate decreases
Solution Approach 1:
The invention merges the readout operations by combining signals from multiple photoelectric converters through the floating diffusion node. Multiple converters share common readout circuitry and output paths, allowing simultaneous acquisition of phase difference information in multiple directions without requiring separate readout sequences, thus maintaining high framerate while improving spatial resolution.
Solution Approach 2:
The readout circuit is designed with universal functionality to handle signals from all photoelectric converters through a single shared path. The floating diffusion node and subsequent circuitry serve multiple functions by processing signals from different converters simultaneously, eliminating the need for multiple specialized readout operations and preserving framerate.
3Device complexity
If a single micro lens is used to converge light to multiple photoelectric converters, then the device complexity is reduced, but the manufacturing precision becomes more difficult
Solution Approach 1:
A single micro lens is designed to perform multiple functions by converging light to multiple photoelectric converters simultaneously. This universal lens structure reduces device complexity compared to having separate lenses for each converter, while the shared optical path inherently improves alignment precision by eliminating multiple lens-to-converter alignment requirements.
Solution Approach 2:
The invention merges multiple lens functions into a single micro lens that serves all photoelectric converters within a pixel. This consolidation simplifies the optical structure and reduces manufacturing complexity, while the unified optical path ensures consistent light convergence across all converters, improving alignment precision.
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
The solution enhances the spatial resolution of phase difference information while preventing a reduction in framerate, ensuring accurate focus detection and improved imaging quality.
Implementation Method 1
each of the plurality of pixels includes a first photoelectric converter, a second photoelectric converter arranged in a first direction with respect to the first photoelectric converter, a third photoelectric converter arranged in a second direction intersecting with the first direction with respect to the first photoelectric converter, a fourth photoelectric converter arranged in the second direction with respect to the second photoelectric converter and in the first direction with respect to the third photoelectric converter
Data Source
AI summary
A solid-state imaging device includes pixels in a matrix and a readout circuit that reads signals from a pixel. Each pixel includes a first photoelectric converter, a second photoelectric converter arranged in a first direction relative to the first photoelectric converter, a third photoelectric converter arranged in a second direction relative to the first photoelectric converter, a fourth photoelectric converter arranged in the second direction relative to the second photoelectric converter and in the first direction relative to the third photoelectric converter, and a micro lens for all the photoelectric converters. The readout circuit reads charges from all the photoelectric converters by three readout operations and reads signals so as to be able to identify a signal based on charges generated by only one photoelectric converter. The readout circuit selects the one photoelectric converter from all the photoelectric converters.