Organic Image Sensor Pixel Isolation With Shielded Charge Storage

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Solution Overview

Problem

The existing stacked-type solid-state imaging elements with organic photoelectric conversion layers face issues with imaging image quality due to light incidence on charge storage layers, leading to potential blooming and color mixing between adjacent pixels.

Innovation Solution

A solid-state imaging element is designed with a pixel array section containing light receiving pixels with organic photoelectric conversion layers and charge storage layers, an isolation region between pixels, and a light shielding section, such as a metal film, to suppress light incidence on the charge storage layers, thereby preventing potential blooming and color mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a stacked-type solid-state imaging element with organic photoelectric conversion layer is used, then multi-wavelength light detection capability is improved, but imaging image quality deteriorates due to potential changes in charge storage layer caused by light incidence

Engineering Contradiction:

Improvemulti-wavelength light detection capabilityVSAvoidimaging image quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The charge storage layer is segmented into light-receiving region charge storage layers and isolation region charge storage layers. The isolation region charge storage layer is specifically designed to be shielded from light, separating the light detection function from the charge storage function in different spatial zones, thereby preventing blooming while maintaining multi-wavelength detection capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A light shielding section is introduced as an intermediary element between the incident light and the isolation region charge storage layer. This light shielding section absorbs or blocks light before it can reach the isolation region charge storage layer, preventing potential changes that would cause blooming and color mixing, while allowing the organic photoelectric conversion layer to maintain its multi-wavelength detection function

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If isolation region charge storage layer is exposed to light, then charge storage function is maintained, but blooming and color mixing occur between adjacent pixels

Engineering Contradiction:

Improvecharge storage capacityVSAvoidblooming and color mixing

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The harmful effect of light exposure on the isolation region charge storage layer is extracted and removed by introducing a dedicated light shielding section. This allows the isolation region charge storage layer to maintain its charge storage capacity while being protected from light-induced blooming and color mixing effects

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The light shielding section, which initially appears to reduce the functional area of the charge storage layer, actually converts a harmful situation (light exposure causing blooming) into a beneficial one by enabling the isolation region charge storage layer to function properly without light interference, thereby improving overall imaging quality

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

The implementation effectively improves the imaging image quality by preventing changes in the potential of the charge storage layers, reducing blooming and color mixing, and enhancing the overall performance of the organic photoelectric conversion section.

Implementation Method 1

The light shielding section suppresses incidence of light on the charge storage layer located in the isolation region

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a first photoelectric conversion section including an organic photoelectric conversion layer is formed on a light incident side face of a semiconductor layer

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS20240030251A1Solid-state imaging element and electronic device

Publication Date: 2024.01.25 SONY SEMICON SOLUTIONS CORP

AI summary

A solid-state imaging element (1) according to the present disclosure includes a pixel array section (3), an isolation region (10), and a light shielding section. In the pixel array section (3), a plurality of light receiving pixels (2) each including a photoelectric conversion layer (17) made of an organic material and a charge storage layer (23) that stores a charge generated in the photoelectric conversion layer (17) is disposed side by side. The isolation region (10) is provided between the light receiving pixels (2) adjacent to each other in the pixel array section (3). The light shielding section suppresses incidence of light on the charge storage layer (23a) located in the isolation region (10).