Substrate Coloring for Display Backlight Color Uniformity
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Solution Overview
Problem
Existing illumination devices for display systems face efficiency declines due to increased component complexity, leading to production inefficiencies and potential color unevenness in backlighting, particularly when wavelength conversion sheets convert primary light multiple times, causing imbalances in primary and secondary light ratios.
Innovation Solution
Incorporating a coloring portion directly on the substrate of the light source device, which creates a similar color to the primary light and has higher reflectance for primary light than secondary light, thereby absorbing secondary light and preventing its re-entry into the wavelength conversion sheet, reducing color unevenness and simplifying the component structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a wavelength conversion sheet is used to convert primary light into secondary light, then the display device can achieve broader color gamut and improved color performance, but color unevenness occurs when primary light is converted multiple times causing imbalances in primary and secondary light ratios
Solution Approach 1:
The substrate is designed with a coloring portion that creates a similar color to the primary light emitted by the LED. This coloring portion has selective reflectance characteristics, being higher in reflectance for primary light than for secondary light, thereby absorbing excess secondary light and preventing its re-entry into the wavelength conversion sheet. This color-based selective absorption resolves the color unevenness issue without adding complex mechanical or optical components.
2Manufacturing precision
If multiple components are added to the illumination device to control light conversion, then color uniformity can be improved, but production efficiency decreases due to increased number of components
Solution Approach 1:
The coloring portion is directly integrated into the substrate structure that already supports the LED light source. By combining the light source support function with the color control function in a single component, the invention eliminates the need for separate color control components that would increase assembly complexity and reduce production efficiency. The coloring portion is formed as part of the substrate itself, simplifying manufacturing while maintaining color uniformity.
Solution Approach 2:
The substrate serves multiple functions: it supports the LED light source, provides structural integrity, and through its coloring portion, controls the light conversion process by absorbing excess secondary light. This multi-functional design eliminates the need for additional dedicated components, thereby maintaining production efficiency while achieving color uniformity.
3Illumination intensity
If the substrate reflects both primary and secondary light, then overall light output is maintained, but color unevenness increases due to re-entry of secondary light into the wavelength conversion sheet
Solution Approach 1:
The coloring portion of the substrate exhibits spatially varying optical properties, with different reflectance characteristics for different wavelength ranges. Specifically, it has higher reflectance for primary light wavelengths and lower reflectance for secondary light wavelengths. This local quality differentiation allows the substrate to simultaneously maintain overall light output while selectively absorbing excess secondary light to prevent color unevenness.
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 approach enhances production efficiency by reducing the number of components, minimizes color unevenness, and maintains high brightness by optimizing the ratio of primary to secondary light, ensuring consistent illumination.
Implementation Method 1
a wavelength conversion member facing the first face of the substrate, and converting at least a portion of a wavelength, of the light emitted from the light source, into a wavelength having a color different from a similar color of the light emitted from the light source
Implementation Method 2
in the first coloring portion, the primary light may be higher in reflectance than the secondary light
Implementation Method 3
absorbing secondary light and preventing its re-entry into the wavelength conversion sheet
Data Source
AI summary
An illumination device includes: a substrate including a first face; at least one light source provided to the first face, and configured to emit light; and a wavelength conversion member facing the first face of the substrate, and configured to convert at least a portion of a wavelength, of the light emitted from the light source, into a wavelength having a color different from a similar color of the light emitted from the light source, wherein the substrate includes a first coloring portion constituting at least a portion of the substrate, including at least a portion of the first face, and configured to create the similar color.