LED Packaging with Inclined Bonding Layer for Optical Loss Reduction
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Solution Overview
Problem
Semiconductor light emitting devices face issues with optical loss and color variations due to total reflection and packaging inefficiencies, leading to decreased optical efficiency.
Innovation Solution
A semiconductor light emitting device design incorporating a semiconductor LED chip, a light-transmitting film, and a light-transmitting bonding layer with a reflective packaging portion, where the bonding layer extends along the lateral surface of the chip to reduce internal reflections and includes wavelength conversion materials to alter the emitted light's wavelength, enhancing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional LED packaging is used, then manufacturing is simple, but optical loss occurs due to total reflection and packaging inefficiencies
Solution Approach 1:
The packaging structure is divided into multiple functional layers: a light-transmitting bonding layer with a first refractive index, a wavelength conversion layer with a second refractive index, and a reflective packaging portion. This segmentation allows each layer to perform its specific function optimally, reducing total internal reflection losses at interfaces while maintaining manageable manufacturing complexity through modular design.
Solution Approach 2:
Different regions of the packaging structure are assigned different optical properties. The bonding layer has higher refractive index than the wavelength conversion layer to prevent reflection at the LED-chip interface, while the reflective packaging portion has specific reflectivity properties to redirect light. This local optimization of optical properties minimizes overall optical loss without requiring complete redesign of the entire packaging system.
2Manufacturing precision
If conventional bonding is used, then manufacturing is easy, but color variations increase due to packaging inefficiencies
Solution Approach 1:
The patent specifies precise refractive index parameters for different layers: the bonding layer has a refractive index of 1.4-1.7, while the wavelength conversion layer has a lower refractive index. By controlling these optical parameters during manufacturing, color consistency is improved through reduced internal reflections and optimized light extraction, while the parameters remain within achievable ranges for standard manufacturing processes.
3Productivity
If light-transmitting bonding layer with wavelength conversion material is added, then light extraction efficiency improves, but device complexity increases
Solution Approach 1:
The wavelength conversion layer serves multiple functions simultaneously: it converts the wavelength of emitted light to achieve desired color output, and its lower refractive index compared to the bonding layer creates an optical gradient that reduces total internal reflection. This multi-functionality improves light extraction efficiency without requiring separate dedicated layers for each function, thereby limiting the increase in overall device complexity.
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 significantly improves optical efficiency by minimizing optical loss and enhancing light extraction, resulting in improved luminance and color consistency of the emitted light.
Implementation Method 1
At least one of the light-transmitting film and the light-transmitting bonding layer includes a wavelength conversion material, the wavelength conversion material configured to convert light emitted by the semiconductor LED chip into light having a wavelength different from a wavelength of the emitted light
Implementation Method 2
the reflective packaging portion including a reflective material
Implementation Method 3
The light-transmitting bonding layer may be configured to bond the light-transmitting film to the semiconductor LED chip
Data Source
AI summary
A semiconductor light emitting device may include a semiconductor light emitting diode (LED) chip, a light-transmitting film on the LED chip, and a light-transmitting bonding layer between the light-transmitting film and the semiconductor LED chip. At least one of the light-transmitting film and the light-transmitting bonding layer may include a wavelength conversion material configured to convert light emitted by the semiconductor LED chip into light having a wavelength different from a wavelength of the emitted light. The light-transmitting bonding layer may have a lateral inclined region extending to the lateral surface to form an inclined surface. The semiconductor light emitting device may further include a reflective packaging portion surrounding the light-transmitting bonding layer, covering the first surface such that an electrode of the LED chip is at least partially exposed. The reflective packaging portion may include a reflective material.