Pixel Array Sub-pixel Alignment for Focus Detection
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Solution Overview
Problem
Pupil-division phase difference detection in solid-state imaging devices faces challenges in accurately detecting defocus, especially for elongated objects, due to the difficulty in detecting small misalignment between sub-pixels.
Innovation Solution
A solid-state imaging device with a pixel array that includes both first and second pixels, where the sub-pixels of the first pixels are aligned in one direction and those of the second pixels are aligned perpendicular to the first direction, allowing for accurate focus detection and image generation on objects of various shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pupil-division phase difference detection is used with a single sub-pixel alignment direction, then the device complexity is reduced, but the measurement precision of defocus detection deteriorates for elongated objects
Solution Approach 1:
The pixel array is segmented into multiple types of pixels (first pixels with sub-pixels aligned in a first direction, and second pixels with sub-pixels aligned in a second direction perpendicular to the first direction). This segmentation allows each pixel type to specialize in detecting defocus for objects with different orientations, thereby improving measurement precision without significantly increasing overall device complexity.
Solution Approach 2:
Different regions of the pixel array have different sub-pixel alignment directions tailored to the expected orientation of objects in those regions. This local quality approach ensures that each part of the pixel array is optimized for detecting defocus of objects with specific orientations, improving measurement precision for elongated objects regardless of their orientation.
2Ease of manufacture
If sub-pixels are aligned in one direction for phase difference detection, then the ease of manufacture is improved, but the adaptability to detect defocus on objects of various shapes deteriorates
Solution Approach 1:
The pixel array is divided into multiple types of pixels with different sub-pixel alignment directions. This segmentation enables the device to handle objects of various shapes and orientations, improving adaptability while maintaining manufacturing feasibility through standardized pixel unit fabrication.
Solution Approach 2:
The pixel array achieves multi-functionality by incorporating both first pixels and second pixels that can detect defocus for objects oriented in different directions. This universal design allows a single pixel array to handle various object shapes and orientations, improving adaptability without requiring multiple separate detection systems.
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
Enables accurate focus detection and image generation on objects of various shapes, improving focusing accuracy without compromising image quality.
Implementation Method 1
a pixel in which a pair of sub-pixels is provided beneath one microlens is used. This makes it possible for the solid-state imaging device to calculate an amount of out-of-focus (an amount of defocus) on an object from an amount of misalignment (a shift amount) of respective images formed on the pair of sub-pixels.
Data Source
AI summary
There is provided a solid-state imaging device and an electronic apparatus that performs focus detection and image generation on objects of various shapes. A solid-state imaging device includes a pixel array in which multiple pixels are arrayed. The multiple pixels each receive light in a predetermined wavelength band. The pixel array includes at least one or more first pixels and at least one or more second pixels. The at least one or more first pixels each include a pair of sub-pixels provided beneath one microlens. The pair of sub-pixels is aligned in a first direction. The at least one or more second pixels each include a pair of sub-pixels provided beneath one microlens. The pair of sub-pixels is aligned in a second direction. The second direction is perpendicular to the first direction.