Dual-Scattering LED Package for Wide Beam and Thin Backlights
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Solution Overview
Problem
Conventional light emitting device packages face challenges in achieving a large beam angle and uniform brightness while maintaining a small size and high power efficiency, often requiring additional optical components like diffusion lenses that increase device thickness.
Innovation Solution
A light emitting device package design featuring a wiring substrate with semiconductor devices and multiple scattering layers, where the first scattering layer has a refractive index of 1.4 to 2.8 and the second scattering layer includes titanium oxide particles, optimizing light distribution to achieve a maximum intensity in the 45-degree direction without a separate diffusion lens, allowing for a thin and efficient surface light source device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a separate diffusion lens is arranged on the upper portion of the light emitting device package to increase beam angle, then the beam angle is increased, but the thickness of the surface light source device increases
Solution Approach 1:
The patent merges the light emission function and the diffusion function into a single integrated structure. The semiconductor light emitting device itself is designed with a specific geometric configuration (flat top surface, slanted side surfaces) that directly produces wide-angle light emission, eliminating the need for a separate diffusion lens and thereby reducing device thickness.
Solution Approach 2:
Instead of using a conventional approach where light is emitted vertically and then diffused by a lens, the patent inverts the approach by designing the emitting surface to directly emit light at wide angles through its geometric configuration. The slanted side surfaces are specifically designed to emit light in oblique directions, achieving diffusion effect at the source rather than through a separate component.
2Illumination intensity
If conventional light emitting device packages are used, then they provide basic light emission, but they fail to achieve uniform brightness and high power efficiency simultaneously
Solution Approach 1:
The patent applies different geometric characteristics to different parts of the light emitting device. The top surface is designed to be flat for direct light emission, while the side surfaces are designed with specific slant angles to emit light in oblique directions. This local differentiation of geometric properties enables both uniform brightness distribution and high power efficiency by optimizing light extraction in different regions.
Solution Approach 2:
The patent employs asymmetric geometric configuration in the semiconductor light emitting device structure. The side surfaces are designed with specific slant angles relative to the vertical axis, creating an asymmetric shape that promotes uniform light distribution in multiple directions. This asymmetric design, combined with the flat top surface, achieves both brightness uniformity and high power efficiency by controlling light emission patterns in different spatial directions.
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 design achieves a wide beam angle and uniform brightness with high power efficiency, reducing device thickness and eliminating the need for additional optical components, enabling compact and cost-effective applications.
Implementation Method 1
a first scattering layer covering the semiconductor light emitting device, on the surface of the wiring substrate; and a second scattering layer disposed on the first scattering layer
Data Source
AI summary
A light emitting device package may include a wiring substrate. The wiring substrate may include: a first wiring electrode; a second wiring electrode; an insulating support supporting the first wiring electrode and the second wiring electrode; and a surface from which the first wiring electrode and the second wiring electrode are exposed. a semiconductor light emitting device disposed on the surface of the wiring substrate. The light emitting device package may further include: a first scattering layer covering the semiconductor light emitting device, on the surface of the wiring substrate; and a second scattering layer disposed on the first scattering layer. For light emitted from the semiconductor light emitting device, a maximum intensity of a first directional light in a 0-degree direction may be less than a maximum intensity of a second directional light in a 45-degree direction.