Concave Pixel Surface Layout for Phase Difference Autofocus
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Solution Overview
Problem
Existing photoelectric conversion apparatuses, such as solid-state imaging devices, have insufficient ability to detect the angle and directivity of light from a subject, which limits their ability to detect the phase difference of light effectively.
Innovation Solution
A photoelectric conversion apparatus with a semiconductor substrate featuring a concave light-receiving surface inclined with respect to a second surface, where each pixel includes multiple photoelectric conversion elements receiving light from a common microlens, enhancing the detection of light directivity and phase difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flat light-receiving surface is used in conventional photoelectric conversion apparatus, then the structure is simple and easy to manufacture, but the ability to detect the angle and directivity of light is insufficient
Solution Approach 1:
The light-receiving surface is formed with a concave shape instead of being flat, creating an inverted pyramid structure. This curvature change allows incident light from different angles to be directed to different photoelectric conversion elements, enabling the detection of light directivity and angle information while maintaining a relatively simple manufacturing process through conventional etching techniques
2Measurement precision
If multiple photoelectric conversion elements receive light from a common microlens, then the phase difference detection ability is improved, but the device complexity increases
Solution Approach 1:
Each pixel is divided into multiple photoelectric conversion elements (e.g., four elements arranged in a 2x2 pattern), allowing each element to detect light from slightly different angles through the common microlens. This segmentation enables phase difference detection and directivity measurement while keeping the overall pixel structure integrated and manageable
Solution Approach 2:
Multiple photoelectric conversion elements within a single pixel share a common microlens, combining the optical function for all elements. This merging approach reduces the total number of microlenses needed and simplifies the overall structure compared to providing separate microlenses for each element, while still enabling phase difference detection
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 apparatus significantly improves the detection of light directivity and phase difference, enabling more accurate phase difference autofocusing and increasing the range of focus position adjustment, particularly effective in applications with short camera-lens distances like smartphones.
Implementation Method 1
a plurality of photoelectric conversion elements configured to receive light from a common microlens
Data Source
AI summary
A photoelectric conversion apparatus includes a semiconductor substrate that includes at least one pixel having a plurality of photoelectric conversion elements configured to receive light from a common microlens, wherein the semiconductor substrate includes a first surface that is formed of light-receiving surfaces of the plurality of photoelectric conversion elements and a second surface that faces the first surface, and the first surface has a concave shape, and at least a portion of the first surface is inclined with respect to the second surface.