Wavelength-Conversion Backlight Layout for Thin High-Contrast LCDs
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Solution Overview
Problem
Existing light emitting devices face challenges in achieving a high contrast ratio and reduced thickness, particularly in liquid crystal display applications.
Innovation Solution
A light emitting device comprising a mounting board with light sources having a light reflecting layer, a wavelength conversion layer between the light sources and the light diffuser, and scatter reflection portions on the wavelength conversion layer to enhance light distribution and reduce thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a direct-type light emitting device is used to achieve high contrast ratio, then the contrast ratio is improved, but the device thickness increases
Solution Approach 1:
The patent introduces scatter reflection portions on the wavelength conversion layer to redirect light paths in additional dimensions. By positioning these scatter reflection portions at specific locations above the light sources, light is reflected at various angles to reach the light diffuser more efficiently, achieving uniform luminance distribution without increasing the vertical thickness of the device structure
Solution Approach 2:
The patent applies local quality by positioning scatter reflection portions only at specific locations above certain light sources rather than uniformly across all light sources. This localized approach optimizes light distribution in critical areas while maintaining overall device thickness constraints, creating different optical characteristics in different regions of the device
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 solution achieves a direct-type light emitting device with reduced thickness while inhibiting luminance non-uniformity, making it suitable for use in mobile device backlights that require stringent thickness reduction.
Implementation Method 1
each of the light sources having an upper face on which a light reflecting layer is disposed
Implementation Method 2
The wavelength conversion layer is configured to absorb at least a portion of light from the light sources
Implementation Method 3
to emit light having a wavelength which is different from a wavelength of the light from the light sources
Implementation Method 4
Each of the scatter reflection portions is arranged above at least a portion of the upper face of a corresponding one of the light sources
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A light emitting device includes a mounting board, light sources, a light diffuser, a wavelength conversion layer, and scatter reflection portions. Each of the light sources has an upper face on which a light reflecting layer is disposed. The light diffuser is arranged above the plurality of light sources. The wavelength conversion layer is located at least between the light sources and the light diffuser. The wavelength conversion layer is configured to absorb at least a portion of light from the light sources and to emit light having a wavelength which is different from a wavelength of the light from the light sources. The scatter reflection portions are arranged on a surface of the wavelength conversion layer that is closer to the light diffuser. Each of the scatter reflection portions is arranged above at least a portion of the upper face of a corresponding one of the light sources.