Quantum Dot Image Sensor Low Light Sensitivity

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Solution Overview

Problem

Digital imaging devices face challenges in low light conditions due to inadequate signal-to-noise ratio (SNR) and luminance/color noise, leading to poor image quality, as they are typically sensitive only to visible light and lack sensitivity to infrared light.

Innovation Solution

Incorporating quantum dot materials into image sensors to detect both visible and infrared light, allowing for multi-mode operation based on ambient light levels, where infrared data augments visible light data to improve SNR in low light conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If quantum dot materials are incorporated into image sensors to detect both visible and infrared light, then low light sensitivity and signal-to-noise ratio are improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvelow light sensitivityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines visible light detection and infrared light detection into a single image sensor by incorporating quantum dot materials that respond to both spectral ranges. This merging of functions into one integrated sensor improves low light sensitivity by utilizing infrared photons in addition to visible photons, while avoiding the complexity of multiple separate sensors.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses quantum dot materials as a composite material that possesses dual sensitivity to visible and infrared light. These quantum dot structures are integrated into the image sensor to create a material system that can detect both spectral ranges simultaneously, thereby improving low light performance without requiring separate detection systems.

Inventive Principle:
Principle #40Composite materials

2Reliability

If quantum dot materials are incorporated into image sensors to detect both visible and infrared light, then infrared sensitivity is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveinfrared sensitivityVSAvoidmanufacturing precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs quantum dot materials as a composite that inherently provides both visible and infrared sensitivity through its material properties. This approach achieves infrared sensitivity enhancement without requiring complex multi-layer manufacturing or precise alignment of multiple components, thereby managing manufacturing precision requirements.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes quantum dot materials where the optical response parameters can be tuned to detect both visible and infrared wavelengths. By changing the material parameters at the quantum dot level rather than at the device structure level, the patent achieves dual sensitivity while simplifying the manufacturing precision requirements compared to traditional multi-filter approaches.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If traditional image sensors use only visible light detection, then device simplicity is maintained, but image quality in low light conditions deteriorates

Engineering Contradiction:
Improvedevice simplicityVSAvoidimage quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges visible light detection with infrared light detection in a single sensor system. This combination allows the sensor to utilize both visible and infrared photons present in low light environments, thereby improving image quality and signal-to-noise ratio while maintaining relative device simplicity through integration rather than multiple separate systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses quantum dot composite materials that provide dual spectral sensitivity, enabling the sensor to detect both visible and infrared light. This material-based solution improves low light image quality without requiring complex mechanical or optical systems, achieving enhanced performance with minimal increase in device complexity.

Inventive Principle:
Principle #40Composite materials

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

Enhances image quality by compensating for noise in low light environments through simultaneous detection of visible and infrared light, enabling better luminance and color representation in digital images.

Implementation Method 1

quantum dot sensitivity to visible and infrared light

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2487913B1Increased low light sensitivity for image sensors by combining quantum dot sensitivity to visible and infrared light
Publication Date: 2019.04.24 BLACKBERRY LTD
  • EP2487913B1 patent drawingFigure 1
  • EP2487913B1 patent drawingFigure 2
  • EP2487913B1 patent drawingFigure 3

AI summary

A camera unit generates a processed digital image by augmenting color image data with infrared image data according to the level of ambient light exposure. The camera has an ambient light sensor that detects the level of ambient light in the camera unit and an image sensor that provides image data. One or more quantum dot layers may be included in the image sensor. A camera controller adapts the camera unit for operation in different modes that are selectable based on the levels of detected ambient light. The image data is processed into a digital image, according to the selected mode of operation for the camera unit, using color image data only when the level of ambient light is high, but augmenting the color image data with infrared image data when the level of ambient light is low to increase the color luminance of the final processed digital image.