Light Emitting Device Base Segmentation for Thermal Expansion Management
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Solution Overview
Problem
High-density mounting of small-sized light emitting devices on a mounting board poses challenges due to precise spacing requirements and thermal expansion issues, leading to potential wiring discontinuity, short circuits, and joining defects.
Innovation Solution
A light emitting device design featuring a base with conductive patterns on both surfaces, a light reflecting member covering the side surfaces of the light emitting elements, and strategically formed grooves on the base to absorb and release thermal expansion, ensuring reliable heat dissipation and preventing joining defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple CSPs are mounted at high density on a mounting board, then the light distribution design is facilitated and the emission surface area is reduced, but thermal expansion issues cause wiring discontinuity, short circuits, and joining defects
Solution Approach 1:
The base is divided into multiple independent base members by forming grooves between adjacent light emitting elements. This segmentation allows each base member to expand and contract independently during thermal cycles, preventing stress concentration and joining defects while maintaining high mounting density on the mounting board
2Area of stationary object
If the spacing between light emitting elements is reduced to achieve high-density mounting, then the emission surface area is minimized, but precise spacing requirements make manufacturing more difficult
Solution Approach 1:
The grooves formed on the base automatically serve as spacing structures that define the positions of adjacent base members. This self-service feature eliminates the need for separate precision spacing mechanisms, as the grooves themselves provide the necessary spacing while accommodating thermal expansion, thereby maintaining manufacturing feasibility at high density
3Device complexity
If a single large base is used to mount multiple light emitting elements, then the device structure is simplified, but thermal expansion causes wiring discontinuity and short circuits
Solution Approach 1:
The base is segmented into multiple independent base members through formed grooves, allowing each segment to handle thermal expansion independently. This prevents the wiring discontinuity and short circuits that would occur in a single large base while maintaining relatively simple overall device structure
Solution Approach 2:
The grooves are strategically positioned between adjacent light emitting elements to create local separation zones. This local quality change allows thermal expansion to be managed at specific critical locations without requiring complete base separation, balancing structural simplicity with thermal management
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 allows for high-density, uniform arrangement of light emitting devices with improved reliability by effectively managing thermal expansion and contraction, reducing the risk of defects and ensuring consistent luminance distribution and heat dissipation.
Implementation Method 1
forming at least one groove on the second main surface of the undivided base at a position corresponding to a space between the light emitting elements so that the groove reaches the first main surface and the undivided base is divided into a plurality of base members
Data Source
AI summary
A method of manufacturing a light emitting device includes: providing an undivided base having a first main surface and a second main surface on the opposite side from the first main surface, the undivided base having conductive patterns disposed on the first main surface and conductive patterns disposed on the second main surface; mounting a plurality of light emitting elements on the conductive patterns on the first main surface; forming a light reflecting member that integrally covers side surfaces of the light emitting elements and the first main surface of the undivided base; and, after the forming of the light reflecting member, forming at least one groove on the second main surface of the undivided base at a position corresponding to a space between the light emitting elements so that the groove reaches the first main surface and the undivided base is divided into a plurality of base members.