Planar Light Source Groove Design for Uniform Illumination
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Solution Overview
Problem
Conventional planar light sources using high luminance LEDs in backlight modules often experience hot spots at the edges due to excessive spacing between LEDs, leading to non-uniform light distribution and increased manufacturing costs.
Innovation Solution
A planar light source design featuring a light guide plate with grooves on both sides, where LEDs are positioned to optimize the A/P ratio, combined with scattering microstructures and optical microstructures to ensure uniform light distribution, and a reflector to enhance light usage efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the arrangement pitch between adjacent LEDs is increased to reduce the number of LEDs and manufacturing cost, then the manufacturing cost is reduced, but hot spots appear at the edge of the light guide plate and light uniformity deteriorates
Solution Approach 1:
The patent divides the light guide plate into multiple sections with different groove configurations. The light guide plate includes a first groove and a second groove with different depths and/or angles, allowing different regions to be optimized for different functions - some regions for light injection efficiency and others for uniform distribution, thus resolving the contradiction between using fewer LEDs and maintaining uniformity.
Solution Approach 2:
The patent applies different groove characteristics (depth, angle, shape) to different locations on the light guide plate. By making the groove structure non-uniform and location-specific, the system optimizes light distribution locally in each region, preventing hot spots while allowing larger LED spacing overall.
2Illumination intensity
If the A/P ratio is increased to eliminate hot spots and improve light uniformity, then light uniformity is improved, but the distance between LEDs and light guide plate increases reducing light injection efficiency
Solution Approach 1:
The patent introduces grooves with curved or angled surfaces instead of flat surfaces. The grooves have specific angle ranges (e.g., 30-60 degrees) and depth configurations that redirect light at optimal angles, improving both uniformity and injection efficiency by controlling light propagation paths through geometric shaping.
Solution Approach 2:
The patent adds the groove depth dimension to the traditional two-dimensional light guide plate structure. By creating three-dimensional groove features with varying depths and angles, the system controls light distribution in multiple dimensions, achieving uniformity without sacrificing injection efficiency.
3Productivity
If high luminance LEDs are used to reduce the number of LEDs, then the number of LEDs is reduced, but hot spots still appear due to excessive spacing
Solution Approach 1:
The patent introduces grooves as intermediary structures between the LEDs and the light guide plate bulk material. These grooves act as light management features that capture and redistribute light from the LEDs, preventing direct hot spot formation while enabling the use of fewer, higher-power LEDs.
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 design achieves improved light uniformity and reduced manufacturing costs by minimizing hot spots and optimizing light distribution, ensuring a high luminance coverage rate across the active area.
Implementation Method 1
the light guide plate may effectively convert the light emitted by the LED light source into a planar light source
Implementation Method 2
combined with scattering microstructures and optical microstructures to ensure uniform light distribution
Implementation Method 3
a reflector to enhance light usage efficiency
Data Source
AI summary
A planar light source including an LGP and first and second light sources are provided. The LGP has a first surface and a second surface opposite to each other and a first groove and a second groove. The first groove and the second groove are respectively located on the first surface and the second surface, and are respectively located at two sides of a center line of the LGP, where the center line equally divides the first surface and the second surface. The first groove has a first side surface and a first light incident surface, and the second groove has a second side surface and a second light incident surface, where the light sources are disposed in the grooves. The light sources are suitable for respectively providing a light beam entering the LGP through the corresponding light incident surface.