Phase Difference Pixel Polarizing Structure Autofocusing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In solid-state imaging devices, achieving ideal phase difference properties for image plane phase difference autofocusing is challenging due to the difficulty in forming phase difference pixels that match the pupil splitting plane with the photoelectric conversion area, leading to light diffraction, reflection, or absorption, which deteriorates autofocusing accuracy.
Innovation Solution
A solid-state imaging device with phase difference pixels that include a photoelectric conversion unit in a semiconductor substrate, a light blocking film in an insulating layer to shield half of the pixel from light, and a polarizing structure to polarize light passing through the unshielded portion, effectively reducing light leakage and improving phase difference properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase difference pixels are formed with pupil splitting plane matching the photoelectric conversion area, then ideal phase difference properties are achieved, but it is difficult to form such pixels in solid-state imaging devices
Solution Approach 1:
The pupil is divided into two separate regions by the light blocking film, creating distinct first and second light receiving regions. This segmentation allows each region to capture light from different spatial positions, enabling phase difference measurement without requiring the pupil splitting plane to match the photoelectric conversion area exactly.
Solution Approach 2:
A light blocking film is introduced as an intermediary element between the lens and the photoelectric conversion unit. This film creates the necessary pupil splitting effect and generates phase difference information without requiring direct alignment between the pupil splitting plane and the photoelectric conversion area, thus resolving the manufacturing difficulty.
2Ease of manufacture
If distance is left between the pupil splitting plane and the photoelectric conversion area, then pixel formation is easier, but light is diffracted, reflected, or absorbed causing phase difference properties to deteriorate
Solution Approach 1:
The invention changes the optical parameters by introducing a polarizing structure that converts unpolarized light into polarized light. This parameter change in the light's polarization state enables the use of polarization difference information for autofocusing, which is more robust to the distance between the pupil splitting plane and photoelectric conversion area, thereby maintaining autofocusing accuracy despite the manufacturing-friendly separation.
Solution Approach 2:
The light blocking film serves as an intermediary that creates well-defined light receiving regions with clear boundaries. This intermediary structure ensures that even with distance separation, the light paths are properly defined and controlled, reducing unwanted diffraction and reflection effects while maintaining ease of manufacture.
3Measurement precision
If light blocking film is provided to shield half of the phase difference pixel, then pupil splitting is achieved, but light leakage may occur affecting phase difference properties
Solution Approach 1:
The invention changes the light's polarization parameter by introducing a polarizing structure. This allows the system to utilize polarization difference information that is less susceptible to light leakage effects, thereby maintaining pupil splitting accuracy while reducing the impact of light leakage on phase difference properties.
Solution Approach 2:
The invention uses a composite structure combining the light blocking film with a polarizing structure. This composite approach provides both the pupil splitting function and the polarization filtering function, where the polarizing structure helps prevent polarization mixing caused by light leakage, thereby maintaining measurement precision while accounting for potential light leakage.
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 enables excellent phase difference properties and enhanced autofocusing accuracy by minimizing light leakage and diffraction, resulting in improved demosaicing and focusing performance.
Implementation Method 1
a light blocking film that is provided in an insulating layer stacked on the semiconductor substrate, and shields substantially a half of the phase difference pixel from light
Implementation Method 2
a polarizing structure that polarizes light passing through an opening portion not shielded from light by the light blocking film
Implementation Method 3
a photoelectric conversion unit that is formed in a semiconductor substrate and performs photoelectric conversion
Data Source
AI summary
A solid-state imaging device including a phase difference pixel that includes a photoelectric conversion unit formed in a semiconductor substrate, a light blocking film that is provided in an insulating layer stacked on the semiconductor substrate, and shields substantially a half of the phase difference pixel from light, with the boundary being the pupil position, and a polarizing structure that polarizes light passing through an opening portion not shielded from light by the light blocking film. The present technology can be applied to solid-state imaging devices capable of image plane phase difference autofocusing, for example.