PDAF Pixel Signal Reconstruction Using Structure-Direction Detection
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Solution Overview
Problem
Optoelectronic image sensors with PDAF pixels suffer from image errors due to partial shading by apertures, which reduces the image information carried by PDAF pixels, leading to errors in image reconstruction.
Innovation Solution
A method generates output signals for PDAF pixels by interpolating or amplifying pixel signals from surrounding pixels, determining the structure direction to reconstruct the image signal precisely, avoiding errors by choosing the appropriate method based on the structure direction relative to the PDAF pixel arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate PDAF pixel is provided in addition to a color imaging pixel, then depth information can be obtained, but the number of pixels increases and sensor area is consumed
Solution Approach 1:
The patent combines the color imaging function and depth measurement function into a single pixel structure. The color imaging pixel includes both a color filter array for color capture and a phase difference detection mechanism integrated within the same pixel, eliminating the need for separate PDAF pixels while maintaining depth measurement capability.
Solution Approach 2:
The color imaging pixel is designed to perform multiple functions: it captures color information through the color filter array and simultaneously performs phase difference detection for depth measurement by detecting focus states. This multi-functional design allows one pixel to replace what would traditionally require separate dedicated pixels for each function.
2Productivity
If focus detection is performed using a color imaging pixel, then pixel usage is optimized, but chromatic aberration affects focus detection accuracy
Solution Approach 1:
The patent segments the detection function by providing dedicated detection pixels that are separate from the color imaging pixels. These detection pixels are specifically designed for phase difference detection without the interference of color filters, while color imaging pixels maintain their primary function of color capture. This segmentation allows each pixel type to optimize its specific function.
Solution Approach 2:
The patent introduces a microlens array as an intermediary component that directs light to appropriate detection regions. The microlens array works with the detection pixels to enable focus detection while isolating the measurement process from chromatic aberration effects that plague color filter-based detection methods.
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 method effectively reconstructs the image signal of PDAF pixels without errors, ensuring accurate image creation by interpolating or amplifying signals depending on the structure direction, thus overcoming the limitations of partial shading.
Implementation Method 1
a first microlens and a second microlens respectively correspond to the first photodiode and the second photodiode
Data Source
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AI summary
The invention relates to a method for generating an output signal of a PDAF pixel of an optoelectronic image sensor using pixel signals from further pixels arranged in an environment of the PDAF pixel. The image sensor comprises the PDAF pixel within the environment in a row of pixels running along a first direction and at least one further PDAF pixel, and the method comprises: detecting pixel signals of the pixels of the image sensor arranged within the environment; determining a structure direction of an image structure formed on the image sensor from the pixel signals of at least one portion of the pixels arranged within the environment; and generating the output signal of the PDAF pixel. In one case, the output signal is generated as an interpolation signal from the pixel signals of further pixels arranged within the environment and, in another case, it is generated as an amplified signal by correcting the pixel signal of the PDAF pixel with an amplification factor, wherein the output signal of the PDAF pixel is generated as the amplified signal, if the structure direction deviates from the first direction by less than a predefined angle.