Flip-Chip Light Emitting Device Module Without Lead Frames
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Solution Overview
Problem
Conventional light emitting device modules face increased costs and reduced light extraction efficiency due to the use of wires and lead frames for current supply, and are prone to color distortion from heat-induced discoloration of materials like polypthalamide and high reflectivity metals in the package body.
Innovation Solution
The module design omits wires and lead frames, using a flip chip type light emitting device directly coupled to a circuit board, and eliminates the package body and reflective layer, instead employing a phosphor layer and lens made of silicon-based materials to enhance light efficacy and prevent color distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wires and lead frames are used to supply current to the light emitting device, then electrical connection is achieved, but manufacturing cost increases and light extraction efficiency deteriorates
Solution Approach 1:
The patent removes wires and lead frames from the package body, extracting the problematic components that caused both cost increase and light extraction efficiency deterioration. The light emitting device is directly mounted on the circuit board, eliminating the need for separate electrical connection components.
Solution Approach 2:
The patent merges the electrical connection function directly into the mounting structure by bonding the light emitting device electrodes directly to the circuit board. This integration eliminates the need for separate wires and lead frames, reducing component count and improving light extraction.
2Reliability
If wires and lead frames are used to supply current to the light emitting device, then electrical connection is achieved, but light extraction efficiency deteriorates
Solution Approach 1:
The patent removes wires and lead frames from the package body, extracting the problematic components that caused both cost increase and light extraction efficiency deterioration. The light emitting device is directly mounted on the circuit board, eliminating the need for separate electrical connection components.
3Illumination intensity
If a reflective layer made of high reflectivity metal is formed on the package body, then light reflection is improved, but color distortion occurs due to heat-induced discoloration
Solution Approach 1:
The patent removes the reflective layer from the package body, eliminating the source of heat-induced discoloration. Instead of relying on a metal reflective layer that causes color distortion, the design uses the circuit board and mounting structure to provide necessary optical functions without thermal degradation.
Solution Approach 2:
The patent changes the material parameters by eliminating the metal reflective layer and replacing it with a different structural configuration. The circuit board and mounting structure serve dual functions of electrical connection and optical reflection without suffering from thermal discoloration.
4Strength
If polypthalamide (PPA) is used for the package body, then structural support is provided, but heat-induced discoloration occurs
Solution Approach 1:
The patent removes the PPA package body structure, eliminating the material that undergoes heat-induced discoloration. The design transitions to a wire-less, package-less configuration where the circuit board provides structural support without the discoloration problem.
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 design reduces material costs and enhances light extraction efficiency while maintaining uniform color temperature, preventing discoloration and improving manufacturing efficiency.
Implementation Method 1
a phosphor layer 260 surrounding the light emitting device 20
Implementation Method 2
a lens 270 disposed over the phosphor layer 260 and the circuit board 280
Data Source
AI summary
Embodiments provide a light emitting device module including a circuit board, a light emitting device bonded to a conductive layer on the circuit board via a conductive adhesive, a phosphor layer disposed on a side surface and an upper surface of the light emitting device, and a lens on the circuit board and the phosphor layer. A void is generated between the light emitting device and the circuit board.