Image Sensor Using Photo-Detecting Molecule for Sub-Micron Pixel Integration

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Solution Overview

Problem

Conventional CMOS image sensors face challenges in reducing pixel size due to reduced photodiode area, leading to decreased sensitivity and dynamic range, and image resolution is compromised by light diffraction and spreading across adjacent pixels.

Innovation Solution

The image sensor employs sub-micron-sized unit pixels with a photo-detecting molecule layer, charge generation layer, and variable resistance layer, where light absorption generates charges, and secondary electrons alter the resistance state, enabling binary information storage and increased sensitivity through subpixel arrangement and voltage application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pixel size is reduced in conventional CMOS image sensors, then the integration density is improved, but the photodiode area is reduced leading to decreased sensitivity and dynamic range

Engineering Contradiction:

Improveintegration densityVSAvoidsensitivity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces the conventional photodiode-based photoelectric conversion mechanism with a molecular photo-detection mechanism. Molecules are used to detect photons and generate electrical signals, enabling sub-micron pixel sizes while maintaining sensitivity because molecular detection does not require large physical areas like conventional photodiodes do.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of photoelectric conversion from bulk semiconductor photodiodes to molecular-scale detection. This parameter change allows the sensing element size to be reduced to sub-micron dimensions while preserving the photoelectric conversion efficiency and sensitivity through the unique properties of photo-active molecules.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the pixel size is reduced in conventional CMOS image sensors, then the integration density is improved, but the dynamic range is reduced

Engineering Contradiction:

Improveintegration densityVSAvoiddynamic range

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent substitutes the photodiode-based charge generation mechanism with a molecular photo-detection mechanism that can maintain dynamic range performance at sub-micron scales. The molecular system provides a different charge generation and storage mechanism that is not constrained by the area limitations affecting conventional photodiodes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the pixel size is reduced, then the number of pixels per unit area is increased, but light diffraction causes incident light to spread to adjacent pixels reducing image resolution

Engineering Contradiction:

Improvepixel densityVSAvoidimage resolution

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces conventional photodiode light detection with molecular photo-detection at sub-micron scales. The molecular detection mechanism, combined with the unique electrical signal generation and storage properties, enables higher pixel density while maintaining optical resolution by reducing the relative impact of light diffraction effects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 sensitivity and dynamic range by allowing sub-micron pixel formation, reducing light diffraction effects, and improving image resolution by accurately focusing light on individual pixels.

Implementation Method 1

a photo-detecting molecule layer that may generate charges by absorbing light having a certain wavelength

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a charge generation layer that may form a plurality of secondary electrons by receiving the charges from the photo-detecting molecule layer when a voltage is applied to the subpixel

Methodology Applied

Scientific EffectCharge multiplication: Electron Avalanche

Data Source

PatentUS8053719B2Image sensor using photo-detecting molecule and method of operating the same

Publication Date: 2011.11.08 IMBERATEK LLC

AI summary

Provided is an image sensor using a photo-detecting molecule and a method of operating the image sensor. The image sensor may include a plurality of first electrodes disposed parallel to each other and a plurality of second electrodes disposed parallel to each other in a direction perpendicular to the first electrodes and above the first electrodes, and a plurality of subpixels formed in regions where the first electrodes cross the second electrodes. Each of the subpixels may comprise a photo-detecting molecule layer that may generate charges by absorbing light having a certain wavelength, a charge generation layer that may form a plurality of secondary electrons by receiving the charges from the photo-detecting molecule layer when a known voltage is applied between the first electrodes and the second electrodes, and a variable resistance layer, an electrical state of which is changed by receiving the secondary electrons generated from the charge generation layer.