Display Device Low Refractive Index Layer Light Efficiency
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Solution Overview
Problem
Conventional display devices with phosphors suffer from low light use efficiency due to the presence of an adhesive layer between the light source unit and the phosphor, and the higher refractive index of phosphors relative to glass substrates, causing light to be redirected back into the light source unit or not exit the substrate effectively.
Innovation Solution
Incorporating a low refractive index layer between the phosphors and the transparent substrate, along with a reflective member that reflects sideways-emitted light and an air layer between the phosphors and the light source unit, to improve light emission directionality and reduce light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an adhesive layer is inserted between the light source unit and the phosphor to fix the phosphor, then the phosphor can be securely mounted, but light use efficiency decreases because light traveling toward the light source unit enters the adhesive layer and is lost
Solution Approach 1:
The patent removes the adhesive layer from the interface between the light source unit and phosphor, extracting the harmful element that caused light loss. The phosphor is mounted directly on the light source unit without any intermediate adhesive layer, thereby eliminating the problem of light being absorbed or scattered by the adhesive while maintaining secure mounting through direct contact and structural design
Solution Approach 2:
The patent introduces an air layer as an intermediary between the phosphor and the light source unit. This air layer serves as a non-absorbing medium that allows light to pass through without being lost, while still enabling the phosphor to be securely positioned and mounted on the light source unit structure
2Power
If phosphor with higher refractive index is used on glass substrate, then the phosphor can effectively convert light wavelength, but light with large incident angle enters the glass substrate and does not exit toward the viewer, reducing light use efficiency
Solution Approach 1:
The patent introduces an air layer as an intermediary between the phosphor and the glass substrate. This air layer has a lower refractive index than both the phosphor and glass, creating a refractive index gradient that reduces total internal reflection at the phosphor-substrate interface. Light can more effectively pass through the air layer and exit the glass substrate toward the viewer, improving light use efficiency while maintaining the phosphor's wavelength conversion capability
Solution Approach 2:
The patent changes the refractive index parameter at the interface between the phosphor and substrate by introducing air (refractive index ~1.0) between them. This parameter change creates a more favorable optical condition that reduces light trapping within the glass substrate and improves light extraction efficiency toward the viewer
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 light use efficiency by minimizing light redirection back into the light source unit and optimizing light exit from the substrate, thereby improving the overall display performance.
Implementation Method 1
a low refractive index layer that is formed between the phosphors and the transparent substrate and that has a lower refractive index than the phosphors
Implementation Method 2
a reflective member that reflects light that is emitted sideways by the respective phosphors
Implementation Method 3
the phosphors receiving light from the light source unit and emitting light in response thereto
Data Source
AI summary
The purpose of the present invention is to provide a display device in which light emitted from a phosphor is used with enhanced efficiency. A display device is provided with a light source unit for emitting light, a plurality of phosphors for emitting light upon incidence thereon of light from the light source unit, a transparent substrate disposed on the phosphors, a color conversion substrate formed between the phosphors and the transparent substrate and including a reflective member and a low refractive index layer having a refractive index lower than that of the phosphors, and an air layer between the phosphors and the light source unit.