Imaging Pixel Electrode Coupling for Accurate Phase Difference Detection

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Solution Overview

Problem

The existing solid-state imaging devices face limitations in improving light detection sensitivity due to light shielding films and unnecessary charge generation, which hinders miniaturization and accuracy in phase difference detection.

Innovation Solution

The design includes a substrate with a matrix pixel array unit comprising normal pixels, phase difference detection pixels, and adjacent pixels, where the lower electrode of the adjacent pixel extends to cover the phase difference detection pixel area, allowing for improved light utilization and charge management without the need for additional discharge mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a light shielding film is provided to block light in phase difference detection pixels, then asymmetric sensitivity is achieved, but light detection sensitivity is limited

Engineering Contradiction:

Improvephase difference detection accuracyVSAvoidlight detection sensitivity

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent removes the light shielding film from the phase difference detection pixel structure. Instead of blocking light with a film, the invention uses a different approach where the lower electrode configuration itself creates the necessary asymmetric sensitivity without sacrificing light intake, thereby extracting the harmful light-blocking function while preserving the useful phase difference detection capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The lower electrode is designed to serve multiple functions: it acts as both the electrode for photoelectric conversion and the structural element that creates asymmetric sensitivity for phase difference detection. This multi-functional design eliminates the need for separate light shielding films while maintaining detection accuracy

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If a discharge mechanism is provided to remove unnecessary charge, then noise is reduced, but device area increases

Engineering Contradiction:

Improvesignal qualityVSAvoidpixel area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent merges the charge storage function and the discharge function into the existing lower electrode structure. The lower electrode serves as both the charge storage electrode for photoelectric conversion and the discharge path for unnecessary charges, eliminating the need for separate discharge mechanisms and reducing overall pixel area

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lower electrode is designed to perform multiple functions simultaneously: storing necessary charges for image signal generation and providing a discharge path for unnecessary charges. This multi-functional design reduces the need for additional components and enables pixel miniaturization

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If the lower electrode is provided separately for each normal pixel section, then charge management is simplified, but device complexity increases

Engineering Contradiction:

Improvecharge managementVSAvoidelectrode configuration

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the lower electrode structure across adjacent pixel sections. Instead of providing separate lower electrodes for each normal pixel section, the lower electrode extends continuously from the adjacent pixel section into the phase difference detection pixel section, simplifying the overall electrode configuration while maintaining ease of charge management

Inventive Principle:

Principle #5Merging (Combining)

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 enhances detection sensitivity while enabling miniaturization of pixels, improving the accuracy of phase difference detection and reducing noise, thereby enhancing the overall performance of the solid-state imaging device.

Implementation Method 1

each of the normal pixel, the phase difference detection pixel, and the adjacent pixel has a photoelectric conversion film

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS11743614B2Solid-state imaging device and electronic apparatus with a charge storage unit electrically connected to each of a lower electrode of a phase difference detection pixel, an adjacent pixel and a normal pixel via a capacitance, wherein the capacitance connected to the adjacent pixel is greater than a capacitance connected to the normal pixel

Publication Date: 2023.08.29 SONY SEMICON SOLUTIONS CORP

AI summary

There is provided a solid-state imaging device that includes a substrate having a pixel array unit sectioned into a matrix, a plurality of normal pixels, a plurality of phase difference detection pixels, and a plurality of adjacent pixels adjacent to the phase difference detection pixels, each provided in each of the plurality of sections, in which each of the normal pixel, the phase difference detection pixel, and the adjacent pixel has a photoelectric conversion film, and an upper electrode and a lower electrode that sandwich the photoelectric conversion film in a thickness direction of the photoelectric conversion film, and the lower electrode, in the adjacent pixel, extends from the section in which the adjacent pixel is provided to cover the section in which the phase difference detection pixel adjacent to the adjacent pixel is provided, when viewed from above the substrate.