Quantum Dot Modulated Light Source for Display Color Accuracy

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Solution Overview

Problem

Existing light sources emit a wide range of wavelengths, which are not optimized for display systems, leading to image inversions, restrictive viewing angles, and undesirable color representations, resulting in poor image quality.

Innovation Solution

A modulated light source with quantum dots that regenerate light within prescribed ranges of wavelengths, allowing for accurate composition of light wavelengths and intensities, even across varying temperatures, and can be used in conjunction with other optical components to support a wide color gamut and dynamic contrast levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing light sources emit a wide range of wavelengths, then the light source can illuminate all pixels, but the display system suffers from image inversions, restrictive viewing angles, and undesirable color representations

Engineering Contradiction:
Improvewavelength coverageVSAvoidimage quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent segments the broad wavelength spectrum into multiple discrete wavelength ranges, each corresponding to specific optical configurations. Different quantum dot layers emit light at different discrete wavelengths (e.g., blue, cyan, green, yellow, orange, red), allowing the display system to selectively activate only the wavelengths optimized for each optical configuration, thereby eliminating image inversions and color distortions while maintaining comprehensive wavelength coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning specific wavelength ranges to specific optical configurations or viewing zones. Each quantum dot layer is engineered to emit light with precise wavelength characteristics tailored to the requirements of particular optical paths or display regions, ensuring optimal image quality for each local area rather than using a uniform broad-spectrum light source across the entire display.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If a light source uses broadband white light, then it can support all color filters, but the color gamut and color accuracy are degraded

Engineering Contradiction:
Improvecolor filter compatibilityVSAvoidcolor accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent extracts only the necessary wavelength components from the broadband spectrum by using quantum dot layers that emit discrete, narrow bandwidth wavelengths. Instead of using broadband white light that includes all wavelengths, the system selectively generates only the specific wavelengths needed for accurate color reproduction, thereby improving color accuracy while maintaining compatibility with color filter arrays through precise wavelength matching.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the spectral parameters of the light source by using quantum dots with precisely controlled size and composition to emit light at specific wavelengths. By adjusting the quantum dot size, material composition, and shell structure, the system can tune the emission wavelengths to match the optimal sensitivity ranges of the color filters, thereby achieving superior color accuracy compared to fixed broadband white light sources.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If existing light sources use wide wavelength ranges, then they can provide sufficient brightness, but the viewing angles are restricted and image inversions occur

Engineering Contradiction:
ImprovebrightnessVSAvoidviewing angle
Core Design Contradiction:
Illumination intensityVSEase of operation

Solution Approach 1:

The patent implements dynamics by enabling selective activation of different quantum dot layers based on the required optical configuration and viewing angle. The system can dynamically adjust which wavelength ranges are emitted to match the current display mode or viewing conditions, allowing optimal brightness and viewing angle performance for different operational states rather than being constrained by a fixed broadband spectrum.

Inventive Principle:
Principle #15Dynamics

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

The modulated light source provides highly accurate color values and detailed images by emitting light with precise wavelength and intensity profiles, enhancing image quality and compensating for color shifts in RGB LEDs, while maintaining performance across a wide range of temperatures.

Implementation Method 1

one or more (light) modulation layers, which, when stimulated by incident broadband first light, are configured to regenerate second light within prescribed ranges of light wavelengths

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

quantum dots, each type of which is configured to produce a part of a single color component in the second color components in the second light

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP2466994B1Quantum dot modulation for displays
Publication Date: 2020.03.25 DOLBY LABORATORIES LICENSING CORP
  • EP2466994B1 patent drawingFigure 1A~1B
  • EP2466994B1 patent drawingFigure 1C
  • EP2466994B1 patent drawingFigure 2A~2B

AI summary

Modulated light sources are described. A modulated light source may have first light sources that are configured to emit first light, which has first color components that occupy a range that is beyond one or more prescribed ranges of light wavelengths. The modulated light source may also have a light converter that is configured to be illuminated by the first light. The light converter converts the first light into second light. The second light has one or more second color components that are within the one or more prescribed ranges of light wavelengths. Strengths of the one or more second color components in the second light are monitored and regulated to produce a particular point within a specific color gamut.