Image Sensor Pixel Array Segmentation for Multi-Wavelength Capture

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Solution Overview

Problem

Existing CMOS image sensors face limitations in spatial response and spectral resolution due to the degradation caused by color filter materials, which restrict their ability to capture high-resolution images across different wavelengths efficiently, leading to potential blurring when taking multiple exposures.

Innovation Solution

The implementation of an image sensor configuration with an array of photodiode pixels and capacitors, controlled by an address decoder that allows for separate exposure control of interlaced rows or columns, enabling rapid capture of two-dimensional images at different wavelengths by utilizing multiple storage elements per pixel to store and manage charge effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple exposures are taken to capture different wavelengths, then spectral resolution is improved, but capture time increases and blurring occurs

Engineering Contradiction:
Improvespectral resolutionVSAvoidcapture time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The pixel array is divided into multiple independently controllable segments (e.g., interlaced rows or columns) that can be exposed simultaneously at different wavelengths. The address decoder separates the array into two or more parts, each part separately controlled to take at least one exposure separate from each other part, enabling parallel multi-wavelength capture without increasing total capture time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a temporal dimension to the segmentation by enabling different segments to be exposed at different times within the same capture cycle. The address decoder controls segments to take exposures at different times, allowing spectral information to be captured across multiple time points while maintaining spatial resolution through the segmented architecture.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If multiple exposures are taken to capture different wavelengths, then spectral resolution is improved, but image quality deteriorates due to blurring

Engineering Contradiction:
Improvespectral resolutionVSAvoidimage quality
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

By segmenting the pixel array into independently controllable parts and exposing each segment simultaneously at a specific wavelength, the patent eliminates motion blur that would occur with sequential full-array exposures. Each segment captures a complete spatial frame at its designated wavelength, ensuring image quality while achieving spectral resolution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The address decoder implements periodic control signals that systematically activate different segments in a repeating cycle. This periodic action ensures that each segment receives the appropriate exposure timing and duration, maintaining consistent image quality across all wavelength channels while enabling comprehensive spectral capture.

Inventive Principle:
Principle #19Periodic action

3Productivity

If the entire pixel array is exposed simultaneously, then capture speed is improved, but spectral resolution deteriorates

Engineering Contradiction:
Improvecapture speedVSAvoidspectral resolution
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The pixel array is segmented into multiple independently controllable parts, each assigned to capture a specific wavelength range. The address decoder enables simultaneous exposure of different segments at different wavelengths, achieving both high capture speed (parallel operation) and spectral resolution (wavelength-specific segmentation).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each pixel segment is designed with multi-functionality, capable of capturing different wavelength ranges by receiving different control signals from the address decoder. This universal design allows the same hardware to perform both high-speed imaging and spectral analysis by dynamically assigning wavelength ranges to different segments based on exposure requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables cost-effective, rapid capture of images at different wavelengths, reducing capture time and minimizing blurring, while maintaining high spatial and spectral resolution, even with multiple exposures.

Implementation Method 1

an array of photodiode pixels configured to be sensitive to light, each pixel comprising a photodiode

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

a plurality of capacitors configured to store charge from the photodiode

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3185541B1An image sensor configuration
Publication Date: 2020.03.18 STMICROELECTRONICS (RES & DEV) LTD
  • EP3185541B1 patent drawingFigure 1
  • EP3185541B1 patent drawingFigure 2
  • EP3185541B1 patent drawingFigure 3

AI summary

An image sensor comprising: an array of photodiode pixels configured to be sensitive to light, each pixel comprising a photodiode, and a plurality of capacitors configured to store charge from the photodiode; an address decoder configured to control the array of photodiode pixels such that the array of photodiode pixels may be divided into two or more parts, each part separately controlled to take at least one exposure separate from each other part.