Image Sensor Pixel Groups Enabling Single-Shot PDAF and HDR
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Solution Overview
Problem
Conventional image sensing devices face challenges in performing phase-difference detection autofocus (PDAF) and high dynamic range (HDR) imaging efficiently, often resulting in time delays and motion artifacts due to separate image data acquisition and processing.
Innovation Solution
An image sensing device with a pixel array structure that includes multiple unit pixels in a pixel group, capable of generating phase difference data and HDR images through a single image capture, utilizing a processor to combine signals from these pixels for autofocus and dynamic range enhancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate image data acquisition and processing is performed for PDAF and HDR imaging, then each function can be processed independently, but time delays and motion artifacts occur
Solution Approach 1:
The patent combines PDAF and HDR imaging functions into a single image capture process. Multiple unit pixels within each pixel group simultaneously capture light signals, enabling both phase difference detection and high dynamic range imaging to be performed in one shot, thereby eliminating time delays and motion artifacts that would result from separate capture operations.
Solution Approach 2:
The patent divides each pixel into multiple unit pixels (first, second, third, and fourth unit pixels) with different light reception areas and spectral sensitivities. This segmentation allows each unit pixel to capture specific portions of the light signal, which are then processed to generate both PDAF phase difference data and HDR image data from the same captured scene.
2Adaptability or versatility
If multiple unit pixels with different light reception areas are used in a pixel group, then HDR imaging capability is enhanced, but device complexity increases
Solution Approach 1:
The patent designs each pixel group to serve multiple functions simultaneously. The same set of unit pixels with different light reception areas is used for both PDAF (phase difference autofocus) and HDR (high dynamic range) imaging. This multi-functionality reduces overall device complexity compared to having separate dedicated structures for each function.
Solution Approach 2:
The patent introduces spectral dimension by assigning different spectral sensitivities to different unit pixels within the same pixel group. In addition to the spatial dimension represented by different light reception areas, this spectral differentiation enables the system to extract multiple types of information (phase difference and dynamic range) from the same physical structure without increasing its complexity.
3Measurement precision
If unit pixels with smaller light reception areas are used, then measurement precision for phase difference detection is improved, but light gathering capability decreases
Solution Approach 1:
The patent merges the advantages of different light reception area configurations by combining unit pixels with smaller light reception areas (for precise phase difference measurement) with unit pixels with larger light reception areas (for enhanced light gathering). This combination is achieved through the multi-unit pixel structure within each pixel group, where different unit pixels serve different functional roles.
Solution Approach 2:
The patent applies local quality by assigning different characteristics to different unit pixels within the same pixel group. Specifically, certain unit pixels are designed with smaller light reception areas optimized for precise phase difference detection, while other unit pixels have larger light reception areas optimized for light gathering. This localized optimization allows each unit pixel to excel at its specific function while the overall pixel group achieves both precision and light gathering capability.
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 device achieves high-quality HDR imaging with reduced time delays and motion artifacts by processing signals from multiple unit pixels within a single pixel group, enhancing autofocus accuracy and dynamic range.
Implementation Method 1
each of the first to fourth unit pixels of a pixel group includes optical filters operable to transmit incident light corresponding to a same color
Implementation Method 2
the first unit pixel and the second unit pixel that are included in the pixel group are located adjacent to each other and include portions of a first microlens
Implementation Method 3
first to fourth unit pixels that are configured to respond to incident light and generate electrical signals
Data Source
AI summary
An image sensing device includes a plurality of pixel groups, each pixel group including first to fourth unit pixels that are configured to respond to incident light and generate electrical signals, and wherein each of the first to fourth unit pixels of a pixel group includes optical filters operable to transmit incident light corresponding to a same color, wherein the first unit pixel and the second unit pixel that are included in the pixel group are located adjacent to each other and include portions of a first microlens, and wherein a light reception area of the third unit pixel of the pixel group has a size smaller than a size of a light reception area of the fourth unit pixel of the pixel group.