Pixel Array Sub-pixel Segmentation for Color Depth Imaging
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Solution Overview
Problem
Current image sensors face challenges in simultaneously capturing high-quality color and depth images due to limitations in pixel array design and signal processing, particularly in integrating phase differences and photogate signals, which affect image resolution and operational efficiency.
Innovation Solution
The proposed solution involves a pixel array with sub-pixels connected through a floating diffusion node and a readout circuit, utilizing a photogate controller to generate phase-differentiated photogate signals for each sub-pixel, and a signal processor to generate color and depth images based on pixel signals from the array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pixel array is designed to simultaneously capture color and depth images, then image resolution and quality improve, but device complexity increases due to multiple sub-pixels and photogate signals
Solution Approach 1:
The pixel array is segmented into multiple sub-pixels (first, second, third, and fourth sub-pixels) within each pixel unit, where each sub-pixel is associated with specific photogate signals having different phase differences. This segmentation enables simultaneous capture of color and depth information while maintaining organized signal processing paths.
Solution Approach 2:
Each pixel unit in the array serves multiple functions by incorporating both color imaging capability (through photoelectric conversion elements) and depth imaging capability (through phase-differentiated photogate signals). The same pixel structure handles both functions, reducing the need for separate systems.
2Measurement precision
If photogate signals with different phase differences are applied to multiple sub-pixels, then depth image accuracy improves, but signal processing complexity increases
Solution Approach 1:
Different phase-differentiated photogate signals (0°, 90°, 180°, 270°) are selectively applied to different sub-pixels based on their specific positions and functions. Each sub-pixel receives the appropriate phase signal needed for its role in depth measurement, optimizing local signal quality while maintaining overall system coherence.
Solution Approach 2:
The photogate controller acts as an intermediary that generates and distributes phase-differentiated photogate signals to the appropriate sub-pixels. This intermediary component manages the complexity of signal distribution, allowing the pixel array to process multiple phase signals systematically without overwhelming processing complexity.
3Productivity
If multiple photogate signals are integrated during the integration period, then image capture efficiency improves, but operational complexity increases
Solution Approach 1:
The photogate signals are applied periodically during the integration period with specific phase differences (0°, 90°, 180°, 270°). This periodic application allows systematic integration of multiple signals over time, improving capture efficiency while maintaining manageable operational complexity through regular signal patterns.
Solution Approach 2:
The integration process continuously accumulates photocharges from multiple photogate signals throughout the integration period without interruption. This continuous action ensures that all phase-differentiated signals are fully utilized, maximizing image capture efficiency while the systematic approach keeps operational complexity controlled.
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 enables simultaneous and efficient capture of color and depth images by optimizing pixel signal processing and integration, improving image resolution and reducing operational complexity.
Implementation Method 1
a photoelectric conversion element configured to accumulate photocharges generated due to reflected light that is incident thereto
Data Source
AI summary
Provided are a pixel array and an image sensor including the same. The pixel array includes a plurality of sub-pixels adjacent to each other and a readout circuit connected to the plurality of sub-pixels through a floating diffusion node. Each of the sub-pixels includes a photoelectric conversion element, an overflow transistor connected to the photoelectric conversion element, a phototransistor connected to the photoelectric conversion element and the overflow transistor, and a storage element connected to the phototransistor.