Light Emitting Device Recessed Reflective Covering Thermal Stress
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Solution Overview
Problem
Existing light emitting devices face issues with thermal stress accumulation and cracking in light reflective covering members due to thermal expansion, which can lead to corrosion and reduced performance, especially when used in lighting units or display applications.
Innovation Solution
A light emitting device configuration with a recessed light reflective covering member over the intermediate wiring, reducing thermal stress and exposure to the environment, while facilitating stable mounting and reducing corrosion risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the light reflective covering member is provided flat over the semiconductor light emitting elements, then the manufacturing process is simplified, but thermal stress accumulation and cracking occur due to thermal expansion
Solution Approach 1:
The light reflective covering member is extended in the thickness direction to form a protruding portion that covers the lateral surface of the semiconductor light emitting element. This dimensional extension allows the covering member to accommodate thermal expansion differences between materials, reducing thermal stress and preventing cracking while maintaining manufacturing simplicity.
2Reliability
If the light reflective covering member covers the lateral surface of the semiconductor light emitting element, then corrosion protection is improved, but the device structure becomes more complex
Solution Approach 1:
The light reflective covering member integrates multiple functions: it provides corrosion protection for the lateral surface of the semiconductor light emitting element, reflects light to improve extraction efficiency, and accommodates thermal expansion. By combining these functions into a single component rather than separate protective layers and reflective layers, the structure remains relatively simple while achieving multiple benefits.
3Reliability
If the light reflective covering member is extended in the thickness direction, then thermal stress is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The thickness of the light reflective covering member is optimized within a specific range to balance thermal stress reduction and manufacturing feasibility. By carefully selecting the thickness parameter, the design achieves effective thermal stress mitigation while remaining compatible with standard manufacturing capabilities, avoiding excessive precision requirements.
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 recessed configuration effectively reduces thermal stress and corrosion, enhancing the reliability and longevity of the light emitting device by preventing cracks and maintaining performance in various applications.
Implementation Method 1
a light reflective covering member covering a lateral surface of the semiconductor light emitting element
Data Source
AI summary
A light emitting device includes a first light emitting element, a second light emitting element, a substrate, and a light reflective covering member. A first land is provided in a substrate front surface and includes a first terminal and a second terminal. A second land is provided in the substrate front surface and includes a third terminal and a fourth terminal. An intermediate wiring is provided between the first land and the second land in the substrate front surface. A first wiring is provided in a substrate back surface and is electrically connected to the first terminal through a first through-via. A second wiring is provided in the substrate back surface and is electrically connected to the fourth terminal through a second through-via. A third wiring is provided in the substrate back surface and is electrically connected to the second terminal and the third terminal through a third through-via.