LED Resin Cover Structure to Prevent Sink Marks
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Solution Overview
Problem
The existing methods for manufacturing light emitting devices using LEDs face challenges in forming a stable resin member, particularly due to the generation of 'sink marks' during the curing process, which affects the uniformity and stability of the reflective resin layer, especially when protective elements are not adequately arranged between light emitting elements.
Innovation Solution
A method involving the use of first and second protruding members on a collective substrate, where the second protruding member is harder than the cover member, to prevent resin shrinkage and ensure a stable shape during the singulation process, thereby maintaining the height and stability of the resin member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If protective elements are arranged between light emitting elements to prevent sink marks, then the stability of resin member shape is improved, but device complexity increases
Solution Approach 1:
The patent uses protruding members made of inexpensive materials (such as resin or metal) that are arranged on the collective substrate to prevent sink marks. These protruding members serve as temporary support structures during the curing process and are later removed during singulation, eliminating the need for complex protective element arrangements while maintaining resin shape stability.
Solution Approach 2:
The patent changes the physical parameters of the mold by incorporating protruding members with specific heights and positions. These protruding members create physical constraints that prevent resin shrinkage and sink mark formation during curing. The parameters of the protruding members (height, position, material) are optimized to prevent sink marks without requiring complex protective element structures.
2Stability of the object's composition
If semiconductor elements are arranged to reduce sink marks, then resin member shape stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by arranging protruding members on the collective substrate before injecting the resin. These protruding members are positioned in advance to anticipate and prevent sink mark formation during the curing process. This preliminary arrangement simplifies the manufacturing process compared to requiring precise arrangement of semiconductor elements, as the protruding members can be easily positioned and do not require high precision placement.
3Ease of manufacture
If a mold is not used to manufacture light emitting devices, then manufacturing cost is reduced, but resin member shape stability deteriorates
Solution Approach 1:
The patent segments the mold function into two parts: the collective substrate serves as the base structure, and separate protruding members are arranged on it to provide the shaping function. This segmentation eliminates the need for a complete mold while maintaining resin shape stability. The protruding members can be simple, inexpensive components rather than a complex mold structure, reducing manufacturing costs while preventing sink marks.
Solution Approach 2:
The patent introduces protruding members as intermediary elements between the collective substrate and the resin. These intermediaries provide the necessary support and constraint to prevent resin shrinkage and sink mark formation during curing, replacing the function of a complete mold. The protruding members are simpler and less expensive than a full mold structure, achieving the same shape stability at lower cost.
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 approach allows for the formation of a resin member with a stable shape, reducing the occurrence of 'sink marks' and ensuring consistent height and stability of the light emitting device, enhancing manufacturing efficiency and product quality.
Implementation Method 1
The second protruding member is harder than the cover member
Implementation Method 2
a phosphor layer arranged above the light emitting elements and made of a light transmissive member containing phosphors for converting wavelength of light from the light emitting elements
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2
AI summary
A method of manufacturing a light emitting device includes: mounting light emitting elements on a collective substrate; arranging a first protruding member surrounding the light emitting elements; arranging a second protruding member between the light emitting elements; forming a cover member covering an upper end of the second protruding member, a lateral surface of each of the light emitting elements in a region surrounded by the first protruding member; and singulating the light emitting devices by cutting the cover member, the second protruding member, and the collective substrate at a portion including the second protruding member. The second protruding member is harder than the cover member. An upper end of the second protruding member is located lower than that of the first protruding member but higher than the upper surface of each of the light emitting elements.