Green Spectrum Tuning in Display Units for Rec. 2020 Gamut
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Solution Overview
Problem
Existing display devices struggle to emit green light that meets the Rec. 2020 standard for high color gamut while providing high perception to human M size cone cells.
Innovation Solution
The display device incorporates a display unit that emits an output light with a specific output spectrum, where the intensity integral from 494 nm to 575 nm is greater than double the intensity integral from 380 nm to 493 nm, and the ratio of the secondary peak to the primary peak in the 380 nm to 493 nm range is between 7.0% and 75.0%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the output spectrum is designed with a higher peak and smaller FWHM for pure green light to meet Rec. 2020 standard, then the color gamut is improved, but the perception of M size cone cells for green light is decreased
Solution Approach 1:
The patent applies parameter changes by precisely controlling the spectral parameters of green light emission. Specifically, it designs the output spectrum with a peak wavelength between 520-560 nm and FWHM between 30-50 nm, while simultaneously ensuring the intensity ratio between green (494-575 nm) and blue-violet (380-493 nm) regions falls within 2:1 to 5:1. This dual parameter optimization resolves the contradiction by achieving both high color gamut (through narrow FWHM) and high M cone cell perception (through appropriate intensity distribution).
Solution Approach 2:
The patent applies local quality by creating non-uniform spectral distribution with distinct intensity characteristics in different wavelength regions. The green light region (494-575 nm) is designed with higher intensity concentration to stimulate M cone cells, while the blue-violet region (380-493 nm) is controlled to have lower intensity. This localized spectral quality differentiation allows the display to simultaneously achieve pure green color (narrow FWHM) and high perceptual response from M cone cells.
2Illumination intensity
If the intensity integral from 494 nm to 575 nm is made greater than double the intensity integral from 380 nm to 493 nm, then the green light perception is improved, but the overall spectrum balance becomes more complex
Solution Approach 1:
The patent simplifies spectrum balance complexity by establishing clear quantitative parameters: the intensity integral ratio between green (494-575 nm) and blue-violet (380-493 nm) regions is controlled within 2:1 to 5:1, and the peak wavelength is constrained to 520-560 nm with FWHM of 30-50 nm. These standardized parameter ranges provide a systematic approach to achieving optimal green light perception without requiring complex spectral shaping, thereby resolving the contradiction between improved green perception and reduced device complexity.
Data Source
AI summary
A display device includes a display unit emitting an output light having an output spectrum corresponding to a highest gray level of the display device. An intensity integral of the output spectrum from 494 nm to 575 nm is defined as a first intensity integral, an intensity integral of the output spectrum from 380 nm to 493 nm is defined as a second intensity integral, and the first intensity integral is greater than double of the second intensity integral.