Image Pickup Device Phase Difference Pixel Filter Arrangement
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Solution Overview
Problem
In image pickup devices, the increased arrangement of phase difference pixels for focus detection leads to vignetting issues at the peripheral edges, resulting in decreased light transmission and signal values, and creates a disparity in hue and luminance between phase difference pixel arrangement regions and normal regions, affecting image quality and focus detection precision.
Innovation Solution
The image pickup device incorporates a first pixel region with phase difference pixels arranged according to a predetermined filter pattern, where a specific type of filter is formed on phase difference pixels at regular positions and a different type at irregular positions, and a second pixel region with no valid phase difference pixels, allowing focus detection only from the first pixel region, thereby maintaining consistent filter thickness and reducing noise disparity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If phase difference pixels are arranged in the peripheral edge portion to expand the arrangement region, then the arrangement region is expanded, but vignetting occurs and no valid phase difference pixel signals can be obtained
Solution Approach 1:
The image pickup device divides the pixel array into a first pixel region containing phase difference pixels and a second pixel region containing only image pixels. This segmentation allows the phase difference pixels to be concentrated in a specific region where they can function effectively without vignetting, while the second region maintains full imaging capability.
Solution Approach 2:
Different regions of the pixel array are assigned different functions: the first pixel region is optimized for phase difference detection with appropriate filter arrangements, while the second pixel region is optimized for standard color imaging. This local differentiation ensures each region operates at its optimal performance level.
2Measurement precision
If phase difference pixels are arranged at positions of green pixels in a Bayer array to increase detection sensitivity, then detection sensitivity is improved, but shortage of green pixels for image occurs and image quality decreases
Solution Approach 1:
The device separates phase difference pixels from standard color image pixels into distinct regions. Phase difference pixels can be arranged at green pixel positions in the first region to maximize detection sensitivity, while the second region maintains a complete Bayer array for high-quality color imaging.
Solution Approach 2:
The first pixel region serves dual purposes: it contains phase difference pixels for focus detection while also contributing to the overall image formation. The second pixel region provides pure color imaging functionality, creating a multi-functional system that achieves both focus detection and high-quality imaging.
3Measurement precision
If a specific filter type is arranged on all phase difference pixels to maximize detection sensitivity, then detection sensitivity is improved, but hue and luminance disparity between phase difference pixel region and normal region increases
Solution Approach 1:
The first pixel region uses a specialized filter arrangement optimized for phase difference detection, while the second pixel region uses a standard Bayer array for color imaging. This local differentiation allows each region to have optimal characteristics for its specific function while maintaining overall system coherence.
Solution Approach 2:
The image processing circuit acts as an intermediary that processes signals from both regions differently. It handles phase difference pixel signals for focus detection and standard color pixel signals for imaging, reconciling the different filter arrangements and producing a unified output with consistent hue and luminance.
4Measurement precision
If phase difference pixels are arranged in a region with different filter pattern to optimize detection, then detection function is improved, but disparity in hue and luminance between regions occurs
Solution Approach 1:
The first pixel region employs a filter arrangement specifically optimized for phase difference detection, while the second pixel region uses a standard color filter array. This local specialization allows optimal focus detection in the first region while maintaining natural color and luminance representation in the second region.
Solution Approach 2:
The image processing circuit serves as a mediator that receives signals from both regions with their different filter characteristics. It applies appropriate processing to each region's signals, compensating for the filter differences and producing a unified output with consistent luminance and color across the entire image.
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 enhances focus detection precision, maintains consistent hue and luminance across the image, and suppresses noise and geometric pattern generation, improving overall image quality and focus accuracy.
Implementation Method 1
each of the phase difference pixels is formed by light-shielding a part of an opening of a normal image pixel to prohibit entrance of a light ray from a particular direction and allow entrance of a light ray from another particular direction
Implementation Method 2
image pickup devices in which color filters in a Bayer array are arranged
Implementation Method 3
image pickup device that includes a plurality of pixels arranged in two dimensions
Data Source
AI summary
An image pickup device includes a first pixel region including image pixels and phase difference pixels and a second pixel region including image pixels and including no pixel configured to output a valid phase difference pixel signal, wherein a part of the plurality of phase difference pixels in the first pixel region is arranged at a regular position at which a G filter is formed in a Bayer array and another part is arranged at an irregular position at which a filter that is other than the G filter is formed, and a basic arrangement pattern of filters in the second pixel region is equal to a basic arrangement pattern of filters in the first pixel region.