Flip-Chip LED Hollow Frame for Volume Reduction
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Solution Overview
Problem
Existing light emitting modules have significant volume and footprint overhead due to their design, limiting their use in applications such as portable devices and requiring complex packaging processes.
Innovation Solution
A hollow frame surrounds a self-supporting flip-chip light emitting device, incorporating a wavelength conversion element above the light emitting surface and contact pads on the lower surface for surface mounting, eliminating the need for leadframes and submounts, and using a patterned sapphire substrate for enhanced light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a leadframe with support frame and submount is used, then the light emitting device can be mounted and connected, but the volume and footprint overhead increases significantly
Solution Approach 1:
The patent extracts and eliminates the submount component from the traditional LED packaging structure. The LED chip is mounted directly to the leadframe without requiring a separate submount, thereby removing unnecessary volume and footprint overhead while maintaining electrical and mechanical connections
Solution Approach 2:
The patent merges the functions of the submount and leadframe into a single integrated structure. The leadframe directly provides both the electrical connection function and the mechanical support function that were previously separated across multiple components, reducing overall module size
2Reliability
If a leadframe with support frame and submount is used, then the light emitting device can be mounted and connected, but the packaging process becomes more complex
Solution Approach 1:
The patent removes the submount assembly step from the packaging process. By eliminating this intermediate component, the process requires fewer handling steps, fewer alignment operations, and fewer materials, thereby simplifying manufacturing while maintaining reliable electrical and mechanical connections
Solution Approach 2:
The patent combines multiple functions into the leadframe structure itself, eliminating the need for separate submount assembly operations. This integration reduces the number of process steps required and simplifies the overall packaging workflow
3Ease of operation
If side surfaces are added to facilitate handling, then the light emitting module can be easily picked and placed, but the footprint and volume increase
Solution Approach 1:
The leadframe structure serves multiple functions simultaneously: it provides electrical connections, mechanical support for the LED chip, and integrated handling features through its own geometry. This eliminates the need for additional dedicated handling structures that would increase footprint
4Reliability
If a traditional leadframe structure is used, then external connections can be established, but the light extraction efficiency is reduced
Solution Approach 1:
The patent applies localized reflective surfaces at specific locations within the leadframe structure where they most effectively enhance light extraction. Rather than requiring a complete encapsulant-filled tub, reflective features are strategically placed to redirect light outward, improving efficiency without adding overall structure size
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 minimizes volume and footprint overhead, simplifies the packaging process, and enhances light extraction efficiency, making the modules suitable for small handheld devices and other applications with reduced thermal and optical constraints.
Implementation Method 1
The flip-chip light emitting device may include a patterned sapphire substrate (PSS) upon which the light emitting element is grown, the patterned surface providing enhanced light extraction from the light emitting element
Implementation Method 2
The encapsulant, or the protective coating 28, or the light emitting device 20, may include a wavelength conversion material, such as phosphor, that absorbs some or all of the emitted light and emits light at a different wavelength
Data Source
Figure 1A~1F
Figure 2A~3D
Figure 4~6
AI summary
A hollow frame is configured to surround the periphery of a substantially self- supporting flip-chip light emitting device. The frame may be shaped to also contain a wavelength conversion element above the light emitting surface of the light emitting device. The lower surface of the light emitting device, which is exposed through the hollow frame, includes contact pads coupled to the light emitting element for surface mounting the light emitting module on a printed circuit board or other fixture. The flip-chip light emitting device may include a patterned sapphire substrate (PSS) upon which the light emitting element is grown, the patterned surface providing enhanced light extraction from the light emitting element, through the patterned sapphire substrate.