Solid-State Image Sensor Separated Electrode Focal Point Detection
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Solution Overview
Problem
Existing solid-state image sensors face challenges in forming effective pixels for focal point detection due to dark current issues from separating photoelectric converting films and light shielding problems that reduce signal strength.
Innovation Solution
A solid-state image sensor design featuring a first pixel with a photoelectric converting unit and separated electrodes, where a second pixel has a smaller electrode size with an extending third electrode, allowing for improved focal point detection without increasing the number of light shielding film steps and avoiding dark current from film separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the photoelectric converting film is separated for each pixel to enable focal point detection, then the pixel can detect focal point by using asymmetrical sensitivities, but dark current increases due to separation
Solution Approach 1:
The photoelectric converting film is divided into multiple regions corresponding to different pixels, with each region having independent electrode connections. This segmentation enables each pixel to function independently for focal point detection while maintaining controlled electrical isolation to minimize dark current generation at separation interfaces.
Solution Approach 2:
Different regions of the photoelectric converting film are configured with different electrode arrangements and connection methods. Specifically, pixels intended for focal point detection have asymmetrical electrode configurations to create sensitivity differences, while other pixels use symmetrical configurations for standard imaging, allowing each region to have optimized properties for its specific function.
2Object-affected harmful factors
If a light shielding film is added to prevent light interference in separated pixels, then pixel isolation is improved, but the number of manufacturing steps increases
Solution Approach 1:
The electrode structures serve dual functions: they provide electrical connections for photoelectric conversion and simultaneously act as light shielding barriers between adjacent pixels. By integrating the shielding function into the existing electrode layers, the patent eliminates the need for separate light shielding films, thereby maintaining pixel isolation without increasing manufacturing complexity.
Solution Approach 2:
The electrode structures are designed to perform multiple functions: electrical connection, charge collection, and optical shielding. This multi-functionality reduces the total number of layers and manufacturing steps required, as the same structural elements serve both electrical and optical isolation purposes.
3Measurement precision
If the separated electrode size is reduced to improve focal point detection sensitivity, then detection precision is enhanced, but the vacant region requires additional electrode structure
Solution Approach 1:
The electrode structure extends in the vertical dimension to fill the vacant region created by the reduced horizontal electrode size. By adding depth to the electrode configuration rather than increasing horizontal area, the patent maintains electrical connectivity and structural integrity while preserving the compact pixel design needed for high-resolution focal point detection.
Solution Approach 2:
The third electrode is positioned within or adjacent to the reduced-size first and second electrodes, creating a nested configuration. This nested arrangement efficiently utilizes the vacant space without requiring additional lateral area, maintaining compact pixel structure while providing the necessary electrical pathways for improved focal point detection sensitivity.
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 enhances focal point detection by reducing dark current and maintaining signal strength, enabling more effective pixel formation for improved image sensing capabilities.
Implementation Method 1
a photoelectric converting unit formed of a photoelectric converting film
Data Source
AI summary
A more preferable pixel for detecting a focal point may be formed by using a photoelectric converting film. A solid-state image sensor includes a first pixel including a photoelectric converting unit formed of a photoelectric converting film and first and second electrodes which interpose the same from above and below in which at least one of the first and second electrodes is a separated electrode separated for each pixel, and a second pixel including the photoelectric converting unit in which the separated electrode is formed to have a planar size smaller than that of the first pixel and a third electrode extending at least to a boundary of the pixel is formed in a region which is vacant due to a smaller planar size. The present disclosure is applicable to the solid-state image sensor and the like, for example.