Pixel Separating Electrode for Solid-State Imaging Sensitivity

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Solution Overview

Problem

Conventional solid-state imaging elements face manufacturing challenges due to the need for separate steps in forming high and low sensitivity photoelectric conversion elements, and require high accuracy in color filter overlapping, which becomes difficult with pixel miniaturization.

Innovation Solution

A pixel separating electrode is disposed between unit pixel sections, allowing a shared signal charge among adjoining pixels, eliminating the need for separate steps in manufacturing high and low sensitivity elements and enabling easier sensitivity improvement in low illumination conditions, while also reducing the accuracy required for color filter alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If high sensitivity photoelectric conversion elements and low sensitivity photoelectric conversion elements are formed in separate manufacturing steps, then sensitivity in low illumination conditions is improved, but manufacturing complexity and process difficulty increase

Engineering Contradiction:

Improvesensitivity in low illumination conditionsVSAvoidmanufacturing process complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the pixel separating electrode voltage controllable rather than fixed. By dynamically adjusting the voltage applied to the pixel separating electrode, the same physical structure can adapt its electrical characteristics to achieve different sensitivity levels, eliminating the need for separate manufacturing steps for high and low sensitivity pixels while maintaining the ability to improve low illumination sensitivity through voltage control

Inventive Principle:

Principle #15Dynamics

2Area of moving object

If pixel size is reduced for miniaturization, then device integration is improved, but manufacturing precision requirements for color filter alignment become more stringent

Engineering Contradiction:

Improvepixel sizeVSAvoidcolor filter alignment accuracy

Core Design Contradiction:

Area of moving objectVSManufacturing precision

Solution Approach 1:

The patent introduces the pixel separating electrode as an intermediary element that mediates the relationship between adjacent pixels. This electrode structure, when voltage is applied, creates an electrical boundary that compensates for the reduced physical separation between miniaturized pixels, thereby reducing the stringency of color filter alignment requirements while maintaining pixel isolation and functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

3Illumination intensity

If pixel separating electrode voltage is applied to share signal charge among adjoining pixels, then sensitivity in low illumination conditions is enhanced, but power consumption increases

Engineering Contradiction:

Improvesensitivity in low illumination conditionsVSAvoidpower consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by controlling the voltage to the pixel separating electrode in a time-dependent manner. The voltage is applied selectively during low illumination conditions when sensitivity enhancement is needed, and can be reduced or removed when illumination is sufficient, thereby achieving sensitivity improvement while minimizing continuous power consumption through periodic or conditional activation

Inventive Principle:

Principle #19Periodic action

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 approach enhances sensitivity in low illumination conditions, simplifies manufacturing, and reduces the alignment accuracy needed for color filters, resulting in improved photodiode characteristics suitable for various electronic information devices.

Implementation Method 1

a pixel separating electrode thereabove, wherein, when a given voltage is applied to the pixel separating electrode, a signal charge is shared by the four unit pixel sections

Methodology Applied

Scientific EffectElectrostatic field: Electric Field

Data Source

PatentUS8946611B2Solid-state imaging element and manufacturing method thereof, and electronic information device

Publication Date: 2015.02.03 SHARP KK

AI summary

A color filter is formed using a simple manufacturing method, and bias application to a pixel separating electrode allows sensitivity in low illumination intensity to be improved. In a solid-state imaging element, in which a plurality of unit pixel sections are disposed two dimensionally on a side closer to a front surface of a semiconductor substrate or a semiconductor layer, each unit pixel section having a light receiving section for generating a signal charge by light irradiation, an adjoining unit pixel section is formed in the same color to allow for lesser alignment accuracy of the color filter. A pixel separating electrode is formed in the adjoining unit pixel section, and a signal charge is shared by bias application during low illumination intensity, thereby improving an effective photodiode area.