Light Emitter Packages with Reflective Solder Mask
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Solution Overview
Problem
Conventional light emitter packages suffer from light being trapped or absorbed within gaps between LED chips and side walls, leading to reduced brightness and efficiency, making them more costly and less appealing for adoption.
Innovation Solution
The implementation of a light emitter package design that includes a reflective material, such as electroless silver, applied over a copper trace and covered with a solder mask, which enhances light reflection by reflecting light that permeates through the solder mask back out, thereby improving brightness without the need for additional LED chips or increased power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a blanket coating of white solder mask material is applied within gaps to increase reflection, then light reflection is improved, but light is still absorbed or trapped within gap areas
Solution Approach 1:
The patent applies a composite reflective structure consisting of a white solder mask material layer combined with an underlying reflective layer (such as electroless silver or aluminum). This composite approach allows light that penetrates the solder mask to be reflected back by the underlying metallic layer, preventing energy loss while maintaining the benefits of the solder mask coating.
Solution Approach 2:
The patent introduces an intermediary reflective layer between the solder mask material and the gap walls. This intermediary layer acts as a mediator that captures light passing through the solder mask and redirects it back into the light extraction path, preventing the light from being absorbed by the gap walls or underlying structures.
2Illumination intensity
If more LED chips are used to increase brightness, then illumination intensity is improved, but cost and device complexity increase
Solution Approach 1:
The patent changes the optical parameters of the package structure by implementing enhanced reflective surfaces with specific reflectivity characteristics. The combination of white solder mask material (with its diffuse reflective properties) and underlying metallic reflective layers creates a multi-layer optical system that maximizes light extraction efficiency, allowing existing LED chips to operate at higher effective brightness levels without adding more chips.
Solution Approach 2:
The patent converts the previously harmful light absorption and trapping effects into beneficial reflections. By lining the gap walls and underlying structures with reflective materials, light that would have been lost is now reflected back through the LED chips and package, effectively increasing the utilization of light from each chip without requiring additional chips.
3Illumination intensity
If reflective material is applied over copper trace and covered with solder mask, then light reflection is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent applies the reflective material (such as electroless silver or aluminum) to the copper traces and gap walls before applying the solder mask material. This preliminary action ensures that the reflective layer is in place to reflect light that penetrates the solder mask, while the solder mask is applied last to provide its protective and diffuse reflective functions. This sequence integrates well with standard PCB manufacturing processes.
Solution Approach 2:
The underlying reflective layer serves multiple functions: it provides a highly reflective surface for light extraction, acts as a barrier layer between the copper trace and solder mask, and can serve as an adhesive promotion layer. This multi-functionality reduces the need for additional separate layers or processes, simplifying the overall manufacturing approach.
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 significantly enhances light reflection and extraction, resulting in brighter and more cost-effective light emitter packages that reduce the number of LED chips required, while maintaining or improving brightness levels.
Implementation Method 1
a reflective material, such as electroless silver, applied over a copper trace and covered with a solder mask, which enhances light reflection by reflecting light that permeates through the solder mask back out
Data Source
AI summary
Light emitter packages and related methods having improved performance are disclosed. In one aspect, a light emitter package can include at least one light emitter chip disposed over a substrate or submount. In some aspects, the package can include a reflective polymeric material or polymeric reflector (sometimes referred to as a “solder mask” or “solder mask material”), a reflective material, and a conductive material disposed adjacent each other within a portion of the light emitter package. In some aspects, the reflective material can include a metallic material or metallic reflector applied to side walls of traces and/or within portions of a gap between traces prior to application of the reflective polymeric material within the gap.