Polarizing Pixel Array for Image Sensor Polarization Separation

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Solution Overview

Problem

Existing image sensors face challenges in maintaining sensitivity and separation accuracy of polarization components due to the absorption characteristics of organic and inorganic photoelectric converters, which affect the calculation of polarization information.

Innovation Solution

The image sensor incorporates a polarizing pixel array with different transmission axis directions for each pixel, ensuring a ratio of transmittance in specific wavelength bandwidths and orthogonal directions, allowing for improved sensitivity and accuracy in polarization component separation by utilizing polarizing color pixels with varying transmittance characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the organic photoelectric converting layer increases the absorption of the light orthogonal to the polarized light to improve separation accuracy, then the separation accuracy of polarization component is improved, but the sensitivity of the inorganic photoelectric converter decreases

Engineering Contradiction:

Improveseparation accuracy of polarization componentVSAvoidsensitivity of inorganic photoelectric converter

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The invention divides the photoelectric conversion function into two distinct layers: an organic photoelectric converting layer for detecting polarized light in a specific wavelength range and orientation, and an inorganic photoelectric converter for detecting remaining light. This segmentation allows each layer to be optimized for its specific function without interfering with the other, resolving the contradiction between separation accuracy and sensitivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The organic photoelectric converting layer is designed with specific local properties: it absorbs polarized light of a specific wavelength and orientation while transmitting other light. This localized absorption characteristic enables high separation accuracy for polarization components without requiring the entire system to compromise sensitivity, as the inorganic converter receives the transmitted light.

Inventive Principle:

Principle #3Local quality

2Reliability

If the organic photoelectric converting layer suppresses absorption of light orthogonal to polarized light to maintain sensitivity, then the sensitivity is maintained, but the separation accuracy of polarization component decreases

Engineering Contradiction:

ImprovesensitivityVSAvoidseparation accuracy of polarization component

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

By segmenting the detection function across two layers with different characteristics, the system can maintain overall sensitivity through the inorganic converter while achieving good separation accuracy through the organic layer's selective absorption, without requiring extreme suppression in either layer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The organic photoelectric converting layer acts as an intermediary that selectively processes polarized light components. It mediates between the incident light and the inorganic converter, providing polarization separation functionality while allowing the inorganic converter to maintain sensitivity by receiving the transmitted light components.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 the sensitivity and accuracy of polarization component separation, enabling the image sensor to effectively capture and process polarization information with higher efficiency compared to previous technologies.

Implementation Method 1

the organic photoelectric converting layer absorbs a polarized light of a specific wavelength

Methodology Applied

Scientific EffectSelective absorption: Absorption (EM radiation)

Implementation Method 2

an organic photoelectric converting layer and a light detecting layer including an inorganic photoelectric converter

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS11277552B2Image sensor and image pickup apparatus having the same

Publication Date: 2022.03.15 CANON KK

AI summary

An image sensor includes a first and a second polarizing pixels in each of which transmission axis direction is different. Each of the first and second polarizing pixels has a same wavelength characteristic in transmittance, and has a sensitivity to a first and a second wavelength bandwidths. In each of the first and second polarizing pixels, a ratio of the transmittance in the transmission axis direction in the first and second wavelength bandwidths to a maximum value of the transmittance in the transmission axis direction in all wavelength bandwidths is 0.5 or more. In one of the first and second wavelength bandwidths, a ratio of the transmittance in a direction orthogonal to the transmission axis direction to the transmittance in the transmission axis direction is 0.5 or less, and in the other, the ratio is 0.5 or more.