Semiconductor Light-Emitting Device Dome Shape Control
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Solution Overview
Problem
Conventional surface mount semiconductor light-emitting devices face variability in optical characteristics due to asymmetrical and lopsided dome shapes of the first encapsulating resin, leading to inconsistent directional light emission and color variability, especially when used in wavelength-converting applications.
Innovation Solution
A semiconductor light-emitting device with a circuit board having a rectangular tabular shape and a conductor pattern that forms a first encapsulating material in a fair dome shape by balancing the spread of the encapsulating resin on a circular die-bonding pad, ensuring even path lengths and uniform light emission with the inclusion of wavelength converting materials for various color tones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the first encapsulating resin is applied in a conventional manner, then the manufacturing process is simple, but the dome shape becomes asymmetrical and lopsided causing variability in optical characteristics
Solution Approach 1:
The patent applies asymmetry principle by intentionally designing the conductor pattern with asymmetrical elements (extending in one direction rather than symmetrically in all directions) to counterbalance the natural asymmetrical spreading tendency of the encapsulating resin during the doming process, thereby achieving a symmetrical final dome shape
Solution Approach 2:
The patent changes the geometric parameters of the conductor pattern (extending the pattern in specific directions with specific lengths) to control and balance the spread of encapsulating resin, transforming the resin spreading behavior from asymmetrical to symmetrical through parameter optimization
2Manufacturing precision
If the encapsulating resin spreads unevenly on the die-bonding pad, then the application process remains simple, but the directional light emission becomes inconsistent
Solution Approach 1:
The conductor pattern serves as an intermediary element between the die-bonding pad and the encapsulating resin, mediating the resin's spreading behavior by providing an asymmetrical conductive structure that guides and balances the resin flow to achieve uniform coverage and consistent optical properties
3Manufacturing precision
If a conventional single encapsulating structure is used, then the device structure is simple, but the optical characteristics show color variability
Solution Approach 1:
The patent segments the encapsulating structure into two distinct parts: a first encapsulating resin (transparent silicone resin) for the dome portion that ensures uniform light emission, and a second encapsulating resin (transparent epoxy resin) for the base portion, with each layer serving specific optical and structural functions to achieve color tone uniformity
Solution Approach 2:
The patent uses composite materials by combining two different transparent resins (silicone resin and epoxy resin) with different properties in a layered structure, where the silicone resin provides optimal optical characteristics for light emission while the epoxy resin provides structural stability, achieving both color uniformity and structural integrity
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 achieves high yield and repeatability in forming a fair dome shape, resulting in consistent directional characteristics and uniform color tone emission, suitable for illuminating narrow spaces and vending machines.
Implementation Method 1
a first encapsulating material encapsulating the semiconductor light-emitting chip and a part of the second bonding wire in a dome shape
Implementation Method 2
forming a first encapsulating material in a substantially fair dome shape... consistent directional characteristics
Implementation Method 3
with the inclusion of wavelength converting materials for various color tones
Data Source
AI summary
A semiconductor light-emitting device having favorable optical characteristics can include a first conductor pattern having a die-bonding pad and a second conductor pattern having a wire bonding pad, which are formed on a circuit board. The semiconductor light-emitting device can also include a semiconductor light-emitting chip mounted on the die-bonding pad, a first encapsulating material, which can include a wavelength converting material to wavelength-convert light emitted from the chip and can cover the chip in a substantially fair dome shape on the circuit board, and a second encapsulating resin to cover the first encapsulating material, which can transmit light emitted from the first encapsulating material. Thus, a semiconductor light-emitting device is provided, which can emit a mixture light having various color tones and favorable optical characteristics and which can be used to illuminate goods laid out in a narrow show window, a vending machine, and the like.