Backlight Unit Selective Light Absorption for Wide Color Gamut
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Solution Overview
Problem
Display devices face challenges in achieving a wide color gamut while minimizing brightness loss, particularly in effectively removing yellow and orange light from light sources, which limits their color reproduction capabilities.
Innovation Solution
The implementation of a backlight unit comprising a light source, a reflector sheet with a selective light absorption layer containing tetra-aza-porphyrin to absorb light in the 570 nm to 610 nm range, and an optical sheet with a reflective polarizing sheet to transmit and reflect non-absorbed light, thereby enhancing color gamut while maintaining brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If yellow and orange light are removed from light sources to widen color gamut, then color reproduction accuracy is improved, but brightness is reduced
Solution Approach 1:
The patent segments the light management function into multiple specialized components: a reflector sheet with selective light absorption layer for absorbing yellow/orange light, an optical sheet for additional wavelength-selective absorption, and a reflective polarizing sheet for managing remaining light. This segmentation allows each component to perform its specific function efficiently while working together to maintain overall brightness.
Solution Approach 2:
The patent applies local quality by using materials with specific optical properties in specific locations. The selective light absorption layer contains tetra-aza-porphyrin that absorbs light in the 570-610 nm range (yellow/orange) while being transparent to other wavelengths. This localized spectral filtering achieves color gamut expansion without uniformly reducing all light wavelengths.
2Adaptability or versatility
If selective light absorption materials are added to absorb yellow and orange light, then color gamut is widened, but device structure becomes more complex
Solution Approach 1:
The patent merges multiple functions into integrated components. The reflector sheet combines light reflection with selective light absorption by incorporating the tetra-aza-porphyrin absorption layer directly onto the reflective surface. The optical sheet similarly combines absorption and transmission functions. This merging reduces the need for separate components and simplifies the overall structure.
Solution Approach 2:
The patent uses composite materials to achieve multiple optical properties in single layers. The selective light absorption layer is formed by applying tetra-aza-porphyrin onto a reflective base material, creating a composite structure that simultaneously provides reflection and wavelength-selective absorption. This approach to composite materials enables function integration and structural simplification.
3Measurement precision
If tetra-aza-porphyrin is applied on reflector film to absorb specific wavelength, then yellow and orange light are effectively removed, but manufacturing process becomes more difficult
Solution Approach 1:
The patent specifies precise parameter ranges for the selective light absorption layer to optimize both performance and manufacturability. The tetra-aza-porphyrin concentration is controlled at 0.01-5 wt%, and the layer thickness is maintained at 1-100 nm. These parameter specifications ensure effective yellow/orange light absorption while maintaining practical coating feasibility and material stability.
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 significantly widens the color gamut of the display device by selectively absorbing yellow and orange light, improving color reproduction while minimizing brightness loss, thus providing a more vibrant and accurate color representation.
Implementation Method 1
a selective light absorption layer configured to absorb at least one of yellow light or orange light
Implementation Method 2
a reflector film configured to reflect incident light
Implementation Method 3
a reflective polarizing sheet configured to transmit at least one part of incident light, and to reflect the remaining part of the incident light
Data Source
AI summary
A display device including a backlight unit; and an image forming unit configured to transmit or block light emitted from the backlight unit to create an image, wherein the backlight unit includes a light source, a reflector sheet configured to absorb light having a predetermined wavelength range among light emitted from the light source, and to reflect non-absorbed light, and an optical sheet configured to absorb light having the predetermined wavelength range among the light emitted from the light source, and to transmit non-absorbed light.