Side-Emitting Backlight Structure for Thin Uniform Illumination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional backlighting systems using surface-emitting LEDs require a vertical thickness of 3 mm or greater to achieve homogeneous light distribution, which limits their compactness and efficiency.
Innovation Solution
A backlighting unit utilizing side-emitting semiconductor chips with an encapsulation body featuring depressions that scatter radiation uniformly in lateral directions, reducing vertical thickness to less than 3 mm while maintaining homogeneity through refractive index differences and structural design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If surface-emitting LEDs are used in conventional backlighting systems, then a vertical thickness of 3 mm or greater is required to achieve homogeneous light distribution, but this increases the overall device thickness and reduces compactness
Solution Approach 1:
The patent inverts the conventional surface-emitting LED configuration by using side-emitting LEDs instead. The LED chips are oriented such that the light emission direction is perpendicular to the conventional direction, allowing light to exit through the side surfaces of the chips rather than the top surface. This inversion enables homogeneous light distribution to be achieved with a reduced vertical thickness of less than 3 mm, directly resolving the technical contradiction between light homogeneity and device compactness
Solution Approach 2:
The patent changes the emission dimension from vertical (surface-emitting) to lateral (side-emitting). By orienting the LED chips to emit light through their side surfaces, the light distribution occurs primarily in the lateral direction rather than vertically. This dimensional change allows the backlighting unit to achieve uniform illumination with reduced vertical thickness, as the light mixing occurs through lateral propagation and reflection within the encapsulation body
2Length of stationary object
If the vertical thickness is reduced to increase compactness, then the mixing area is insufficient to achieve homogeneous light distribution
Solution Approach 1:
The patent introduces an encapsulation body with specific local optical properties to enhance light mixing. The encapsulation body has a refractive index different from the surrounding medium, creating localized refraction and reflection effects at the interfaces. Additionally, the encapsulation body may include internal structures such as roughened surfaces or micro-lenses that locally scatter and redirect light, increasing the effective mixing area within the limited vertical space and maintaining homogeneity despite reduced thickness
Solution Approach 2:
The encapsulation body serves as an intermediary element between the side-emitting LED chips and the display panel. It mediates the light distribution by providing a controlled optical environment that enhances lateral light mixing through refraction and reflection. The encapsulation body's specific refractive index and internal structures act as optical intermediaries that redistribute light uniformly across the display area, compensating for the reduced vertical thickness and ensuring homogeneous illumination
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 high degree of luminance homogeneity and compactness by scattering radiation, reducing luminance gradients and hotspot formation, even at low vertical layer thicknesses.
Implementation Method 1
the radiation generated by the semiconductor chip can be scattered uniformly in lateral directions, in particular due to the total reflections
Implementation Method 2
Due to the different spatial orientations of the bottom surface and the side surfaces of the depression and due to a refractive index jump at the bottom surface or at the side surfaces of the depression, the radiation generated by the semiconductor chip can be scattered uniformly in lateral directions
Data Source
AI summary
A backlighting unit includes at least one semiconductor chip, a reflector, and an encapsulation body. The semiconductor chip is configured to generate electromagnetic radiation. The encapsulation body has at least one depression. The semiconductor chip is arranged outside the depression and overlaps with the depression in top view of the encapsulation body. The semiconductor chip is a side-emitting semiconductor chip. The reflector has at least one frame-like sub-region, the opening of which is filled by the material of the encapsulation body and encloses the semiconductor chip and the depression of the encapsulation body in lateral directions. The encapsulation body projects beyond the sub-region in the vertical direction. The encapsulation body at least partially or completely covers edge regions of the sub-region in top view.