Phase Difference Imaging Pixel Layout Without Light Shielding
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Solution Overview
Problem
Existing methods for forming focus detection pixels in solid-state imaging elements, particularly those with photoelectric conversion units on silicon layers, lack an effective approach for creating pixels with asymmetric sensitivity to incident light angles without increasing manufacturing complexity.
Innovation Solution
A solid-state imaging element design featuring a phase difference detection pixel pair with a first photoelectric conversion unit on the upper side of a semiconductor substrate and a second photoelectric conversion unit within the substrate, where the first unit includes a photoelectric conversion film sandwiched between upper and lower electrodes, allowing for efficient focus detection without the need for a light shielding film on the upper surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light shielding film is formed in the vicinity of a silicon layer to increase asymmetry of sensitivity, then focus detection performance is improved, but manufacturing complexity and processing steps increase
Solution Approach 1:
The patent applies asymmetry by configuring the photoelectric conversion units with different light-receiving areas within the same pixel. Specifically, the first photoelectric conversion unit has a larger light-receiving area than the second photoelectric conversion unit, creating inherent asymmetric sensitivity to incident light angles without requiring additional light shielding films. This structural asymmetry directly resolves the contradiction by achieving focus detection performance improvement while avoiding increased manufacturing complexity.
2Adaptability or versatility
If a photoelectric conversion film is laminated on an upper side of a silicon layer, then spectral image sensing capability is improved, but forming focus detection pixels becomes more difficult
Solution Approach 1:
The patent applies segmentation by dividing the photoelectric conversion function into multiple distinct units within each pixel: a first photoelectric conversion unit with a first photoelectric conversion film for general light reception, and a second photoelectric conversion unit with a second photoelectric conversion film for focus detection. This segmentation allows the maintainment of spectral imaging capability while enabling focus detection functionality to be achieved through the asymmetric configuration of these segmented units rather than requiring additional complex processing steps.
Solution Approach 2:
The patent applies multi-functionality by designing the phase difference detection pixel pair to simultaneously perform both spectral image sensing and focus detection functions. The first photoelectric conversion unit handles general imaging while the second unit provides focus detection capability, allowing a single pixel structure to fulfill multiple functions without requiring separate dedicated pixels for each function, thereby maintaining ease of manufacture while enhancing adaptability.
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 design enables the formation of focus detection pixels with asymmetric sensitivity to incident light angles, reducing manufacturing complexity and enhancing imaging element performance without additional processing steps.
Implementation Method 1
a first photoelectric conversion unit arranged at an upper side of a semiconductor substrate and a second photoelectric conversion unit arranged within the semiconductor substrate, wherein the first photoelectric conversion unit includes a first photoelectric conversion film
Data Source
AI summary
A solid-state imaging element including a phase difference detection pixel pair that includes first and second phase difference detection pixels is provided. In particular, each phase difference detection pixel of the first and second phase difference detection pixels includes a first photoelectric conversion unit arranged at an upper side of a semiconductor substrate and a second photoelectric conversion unit arranged within the semiconductor substrate. The first photoelectric conversion film may be an organic film. In addition, phase difference detection pixels may be realized without using a light shielding film.