Backlight Unit Laser Diode Cavity Uniformity
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Solution Overview
Problem
Non-self-emissive display devices, such as LCDs, face challenges in achieving uniform light distribution and improved color reproducibility due to the high directivity of laser beams from laser diodes, which leads to speckle phenomena and inadequate color representation.
Innovation Solution
A backlight unit is designed with a light guide member and a light source unit that includes multiple laser diodes emitting different colors, which are combined through reflection and scattering within a cavity to produce a uniform and combined light output, reducing directivity and enhancing color reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser diodes with high directivity are used as light sources, then color reproducibility is improved due to narrow wavelength band, but uniform light distribution deteriorates due to speckle phenomena
Solution Approach 1:
The light source unit is divided into multiple laser diodes emitting different colors (e.g., red, green, blue) that are spatially separated but optically integrated. Each laser diode maintains its narrow wavelength characteristics while the combined output through the light guide member achieves uniform distribution, resolving the contradiction between color precision and light uniformity.
Solution Approach 2:
The light guide member acts as an intermediary that receives highly directional laser beams from multiple laser diodes and transforms them into uniformly distributed surface light. The light guide member's optical structure diffuses the laser light while preserving the narrow wavelength bands, thereby eliminating speckle phenomena while maintaining color reproducibility.
2Measurement precision
If multiple laser diodes emitting different colors are combined, then color reproducibility is enhanced, but device complexity increases
Solution Approach 1:
Multiple laser diodes emitting different colors are merged into a single integrated light source unit with a common light guide member. This combining approach achieves enhanced color reproducibility through the narrow wavelength bands of individual laser diodes while simplifying the overall structure compared to using separate lighting systems for each color.
Solution Approach 2:
The light guide member serves multiple functions: it guides light from multiple different color laser diodes, diffuses the highly directional laser beams into uniform surface light, and integrates the different wavelength bands into a single coherent output. This multi-functionality reduces device complexity while maintaining superior color reproduction.
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 provides improved uniformity and color accuracy in display devices by mitigating the directivity of laser beams and utilizing the narrow wavelength band of laser diodes for enhanced color representation, resulting in more natural and vivid images.
Implementation Method 1
a light source and a light guide member converting the light emitted from the light source to a surface light... a backlight unit having a laser diode
Implementation Method 2
The light guide member guides and diffuses the light incident thereto through a side portion of the light guide member, and then the diffused light is provided to an entire surface of the display panel
Data Source
AI summary
A backlight unit includes a light guide member including an incident surface extending in a first direction and a light source unit which generates a light, provides the light to the incident surface includes a body member extending in the first direction to define a cavity therein and includes a light exit part defined in one side portion facing the incident surface and connected to the cavity, a first light source disposed in the cavity and including a laser diode generating a first light having a first color, and a second light source disposed in the cavity spaced apart from the first light source in the first direction and including a laser diode generating a second light having a second color where the body member provides a third light having a third color obtained by combining the first and second colors to the incident surface through the light exit part.