Curved Encapsulant Light Emitting Device for Wide Distribution
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Solution Overview
Problem
Existing light emitting devices struggle to achieve both thinness and wide light distribution, particularly in backlight applications where further thinning is required while maintaining high luminance and reliability.
Innovation Solution
A light emitting device configuration featuring a conductive base with a flip-chip mounted light emitting element, a light reflective film on the upper surface, and an encapsulant that covers both, with a curved surface design to enhance light distribution, achieving a batwing light distribution pattern by reflecting and transmitting light effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the backlight is thinned by reducing the height of components, then the overall device thickness is reduced, but the light distribution width deteriorates
Solution Approach 1:
The encapsulant is designed with a curved outer surface instead of a flat surface. The curvature radius is specifically controlled to be 0.25 to 0.50 times the maximum width of the encapsulant. This curved geometry enables light rays to be refracted at various angles, achieving wide light distribution while maintaining a thinned device profile. The curved surface acts as an optical element that spreads light without requiring additional height.
Solution Approach 2:
The patent optimizes specific geometric parameters of the encapsulant to achieve the desired optical performance in a thinned configuration. The curvature radius ratio (0.25-0.50) and the width ratio (Wmax/Lw ≥ 2) are carefully controlled to balance light distribution width with device thickness. By adjusting these parameters, the encapsulant achieves efficient light extraction and wide angular distribution without increasing overall device height.
2Illumination intensity
If a reflector is added to achieve wide light distribution, then light distribution width is improved, but device thickness increases
Solution Approach 1:
The patent combines the encapsulant and reflector functions into a single integrated structure. The encapsulant itself is designed with a curved outer surface that performs both protective encapsulation and light redistribution functions. Additionally, a light reflective film is formed on the upper surface of the light emitting element, merging the reflection function into the existing component layout without requiring a separate reflector structure that would increase thickness.
Solution Approach 2:
The encapsulant serves multiple functions simultaneously: it protects the light emitting element, provides structural support, and acts as an optical element for light redistribution. The curved outer surface of the encapsulant performs light guiding and distribution functions that would otherwise require separate optical components. This multi-functionality eliminates the need for additional thickness-consuming components while achieving wide light distribution.
3Illumination intensity
If the encapsulant width is increased to improve light distribution, then light extraction efficiency is improved, but device area increases
Solution Approach 1:
The curved outer surface of the encapsulant with a specific curvature radius (0.25-0.50 times the maximum width) enables efficient light extraction within a compact area. The curvature geometry allows light rays to be refracted and distributed over a wide angular range without requiring a large encapsulant footprint. This achieves high light extraction efficiency while maintaining a compact device area suitable for thinned backlight applications.
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 results in a thinned light emitting device with improved wide light distribution characteristics, enhancing light extraction efficiency and maintaining high performance, suitable for applications like liquid crystal display backlights and general lighting.
Implementation Method 1
a light reflective film located on an upper surface of the light emitting element
Implementation Method 2
An outer shape of a part of the encapsulant located within a range of elevation angles that is in a range of 10° to 50° from a center of a mounting region at an upper surface of the base on which the light emitting element is mounted is formed to have a curved surface
Data Source
AI summary
A light emitting device includes: a base; a light emitting element; a light reflective film located on an upper surface of the light emitting element; and a encapsulant. A ratio of a maximum width (Wmax) of the encapsulant with respect to a maximum width of the light emitting element, in a side view, is 2 or more. An outer shape of a part of the encapsulant located within a range of elevation angles that is in a range of 10° to 50° from a center of a mounting region at an upper surface of the base on which the light emitting element is mounted is formed to have a curved surface. A ratio (r/Wmax) of a radius of curvature (r) of the curved surface with respect to the maximum width (Wmax) of the encapsulant, in a side view, is in a range of 0.25 to 0.50.