Slim LED Device with 3D Wavelength Conversion
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Solution Overview
Problem
Conventional light-emitting devices, particularly backlights, fail to achieve sufficient slimming and broad light distribution while maintaining high performance and reliability, especially in applications like liquid crystal televisions and general lighting, where design quality and cost-effectiveness are crucial.
Innovation Solution
A light-emitting device structure incorporating a base member with conductor wirings, a flip-chip mounted light-emitting element, a wavelength conversion member that absorbs and re-emits light, a light-reflective film, and an encapsulating member with a specific shape to enhance light distribution, allowing for a batwing light distribution characteristic without the need for a phosphor sheet or secondary lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional backlight structures are used, then light emission function is achieved, but device thickness cannot be sufficiently reduced
Solution Approach 1:
The patent transitions from a planar phosphor sheet configuration to a three-dimensional wavelength conversion member with specific geometric features (convex portions, concave portions, and side surfaces) that extend vertically above the light-emitting element. This dimensional change allows the conversion member to provide sufficient light conversion functionality while maintaining a reduced overall device thickness, as the optical function is distributed across multiple spatial dimensions rather than requiring a large planar area
2Illumination intensity
If a phosphor sheet is used for wavelength conversion, then light conversion is achieved, but device thickness increases and light distribution is insufficient
Solution Approach 1:
The wavelength conversion member is segmented into multiple functional regions: convex portions positioned above the light-emitting element for primary light conversion, concave portions for light collection and redistribution, and side surfaces for lateral light emission. This segmentation allows each region to contribute differently to the overall light distribution, achieving broad angular coverage without increasing device thickness
Solution Approach 2:
The conversion member utilizes vertical dimensionality with features extending above the light-emitting element plane. The convex and concave portions create a three-dimensional structure that redirects light in multiple directions, achieving broad light distribution while maintaining a compact thickness profile that conventional planar phosphor sheets cannot achieve
3Reliability
If the wavelength conversion member is positioned close to the light-emitting element, then device thickness is reduced, but color non-uniformity increases
Solution Approach 1:
Different regions of the wavelength conversion member are designed with distinct geometric properties: convex portions with specific curvatures for focused light conversion, concave portions for light collection, and side surfaces for lateral emission. Each local region is optimized to control light paths differently, ensuring uniform color output despite the compact overall thickness that positions the conversion member close to the light-emitting element
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 configuration provides a slim, high-performance light-emitting device with broad light distribution and various emission colors, reducing color non-uniformity and luminance variations, thus meeting the demands for slim and efficient lighting solutions.
Implementation Method 1
a wavelength conversion member that is disposed on or above an upper surface of the light-emitting element and absorbs at least part of the first light to re-emit light with a wavelength longer than a wavelength of the first light
Implementation Method 2
a light-reflective film that is disposed on an upper surface of the wavelength conversion member
Data Source
AI summary
A light-emitting device includes: a base member that includes conductor wirings; a light-emitting element that is mounted on the base member and emits first light; a wavelength conversion member that is disposed on or above an upper surface of the light-emitting element and is adapted to absorb at least part of the first light and emit second light with a wavelength longer than a wavelength of the first light; a light-reflective film that is disposed on an upper surface of the wavelength conversion member; and an encapsulating member that covers the light-emitting element, the wavelength conversion member, and the light-reflective film. A ratio (H/W) of a height (H) to a width (W) of the encapsulating member is smaller than 0.5.