Image Sensor Pixel Array Segmentation for Infrared and Visible Light

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Solution Overview

Problem

Conventional imaging systems face limitations in miniaturization due to signal-to-noise ratio (SNR) constraints and reduced resolving power when incorporating infrared imaging capabilities, particularly in Bayer Mosaic patterns.

Innovation Solution

The implementation of broadband image pixels and infrared-sensitive pixels in a modified pixel array configuration, such as replacing green pixels with clear or infrared pixels, allows for improved SNR and luminance response by capturing a broader spectrum of light, enabling both visible and infrared imaging without compromising device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a Bayer Mosaic pattern with infrared image pixels is used, then infrared imaging capability is achieved, but resolving power and luminance response are reduced

Engineering Contradiction:

Improveinfrared imaging capabilityVSAvoidresolving power

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The pixel array is segmented into distinct regions: a first region containing infrared-sensitive pixels for infrared imaging, and a second region containing visible light-sensitive pixels (including green pixels) for visible light imaging. This spatial segmentation allows both infrared and visible light imaging capabilities to coexist without the infrared pixels degrading the resolving power and luminance response in the visible light channel, as the visible light pixels maintain their full functionality in the second region.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If green image pixels are replaced with infrared image pixels, then infrared sensitivity is improved, but signal-to-noise ratio deteriorates

Engineering Contradiction:

Improveinfrared sensitivityVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The pixel array is divided into a first region with infrared-sensitive pixels and a second region with visible light-sensitive pixels including green pixels. This segmentation ensures that green pixels are preserved in the second region, maintaining the signal-to-noise ratio for visible light imaging, while infrared-sensitive pixels are concentrated in the first region to achieve infrared sensitivity without compromising visible light performance.

Inventive Principle:

Principle #1Segmentation

3Area of stationary object

If image sensor size is reduced for miniaturization, then device size is reduced, but signal-to-noise ratio decreases

Engineering Contradiction:

Improveimage sensor sizeVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The pixel array is segmented into specialized regions where the first region contains infrared-sensitive pixels and the second region contains visible light-sensitive pixels. This segmentation allows for optimized pixel distribution that maintains adequate signal-to-noise ratio even in reduced sensor sizes, as each region can be tailored for its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the pixel array are assigned different qualities and functions: the first region is optimized for infrared sensitivity while the second region is optimized for visible light sensitivity. This local quality differentiation ensures that each region performs its specific function effectively, maintaining overall signal-to-noise ratio despite miniaturization of the entire sensor.

Inventive Principle:

Principle #3Local quality

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 signal-to-noise ratio, luminance channel fidelity, and resolving power, enabling improved image capture and processing capabilities compared to conventional Bayer filter image sensors.

Implementation Method 1

a first group of image sensor pixels sensitive to infrared light that generate infrared image signals in response to infrared light

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

broadband image pixels and infrared-sensitive pixels in a modified pixel array configuration, such as replacing green pixels with clear or infrared pixels, allows for improved SNR and luminance response by capturing a broader spectrum of light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS10136107B2Imaging systems with visible light sensitive pixels and infrared light sensitive pixels

Publication Date: 2018.11.20 SEMICON COMPONENTS IND LLC

AI summary

An image sensor may have an array of image pixels arranged in color filter unit cells that each have at least one red image pixel that generates red image signals, at least one blue image pixel that generate blue image signals, at least one clear image pixels that generate clear image signals, at least one infrared image pixel that generates infrared image signals, and optionally at least one green image pixel that generates green image signals. The image sensor may be coupled to processing circuitry that performs chroma demosaicking operations on the image signals. The processing circuitry may generate an infrared image using the infrared image signals and a luminance value using the clear, red, blue, and infrared image signals. The processing circuitry may perform point filter operations on the image signals based on the generated luminance value to produce corrected visible light image signals having improved image quality.