Transparent Reflective Device with Sawtooth Structures for Light Extraction
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Solution Overview
Problem
Existing reflectors based on electroplating in lighting fixtures have low light output efficiency due to high light absorption rates, with silver coatings losing 5%, gold coatings losing 9%, and aluminum coatings losing as much as 12% of the emitted light.
Innovation Solution
A transparent reflective device with a light entrance and exit, featuring a reflective wall with continuous sawtooth structures on its inner surface, allowing part of the incident light to be reflected and another part to pass through, optimizing light exit without the need for electroplating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electroplating coating is applied on the reflector surface, then the reflector can be manufactured with standard processes, but the light output efficiency is reduced due to high light absorption
Solution Approach 1:
The patent removes the electroplating coating layer from the reflector surface, extracting the harmful element that causes light absorption. The reflector uses the natural surface of the plastic material without any metal coating, thereby eliminating the 5-12% light loss associated with electroplating materials while maintaining manufacturability through standard injection molding processes.
Solution Approach 2:
The patent changes the surface optical parameters by using a transparent or translucent plastic material with specific refractive index properties instead of metal coatings. The sawtooth structure parameters (angle, depth, spacing) are optimized to achieve total internal reflection, transforming the reflection mechanism from surface-coating-dependent to geometry-dependent, thereby improving light output efficiency.
2Loss of energy
If a transparent reflective device with sawtooth structures is used, then light output efficiency is improved, but the device structure becomes more complex
Solution Approach 1:
The patent segments the reflector surface into multiple sawtooth-shaped prismatic structures instead of using a flat or smoothly curved surface. Each sawtooth element acts as an independent optical unit that redirects light through total internal reflection. This segmentation approach achieves high light output efficiency while the entire structure can be manufactured as a single integrated piece using injection molding, balancing optical performance with manufacturing simplicity.
Solution Approach 2:
The sawtooth structures feature curved or angled surfaces designed to optimize light reflection paths. The specific geometry of the sawtooth elements (with angles typically between 30-60 degrees) creates efficient light redirection while maintaining a compact overall device form factor, thereby improving optical performance without proportionally increasing device complexity.
3Loss of energy
If sawtooth structures are formed on the inner surface, then total reflection and transmission are achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent designs the sawtooth structures with self-aligning features where the geometry of adjacent elements naturally supports and defines each other during the injection molding process. The mold cavity design incorporates the sawtooth pattern directly, allowing the plastic material to self-form the precise angular structures through its own flow and cooling characteristics, reducing the need for post-manufacturing precision adjustments.
Solution Approach 2:
The patent optimizes the sawtooth structure parameters (angle, depth, spacing) to values that are tolerant of normal manufacturing variations. By selecting specific angle ranges (30-60 degrees) and spacing parameters that work effectively across a range of tolerances, the design achieves high light reflection efficiency without requiring ultra-precise manufacturing, thereby balancing optical performance with manufacturing capability.
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 design enhances light output efficiency by ensuring total reflection and transmission, improving the overall light distribution in lighting fixtures without the losses associated with electroplating materials.
Implementation Method 1
each of the sawtooth structures comprising a first refractive surface and a second refractive surface intersected with each other
Implementation Method 2
The reflective device is configured to allow part of incident light, which enters from the light entrance, to be incident onto the reflective wall, to be incident into the optical space by reflection of the reflective wall
Data Source
AI summary
A reflective device and a light source module are provided. The reflective device is transparent, which includes a light entrance, a light exit, and a reflective wall between the light entrance and the light exit. The light entrance is smaller than the light exit, and the reflective wall includes an inner surface and an outer surface, the inner surface including a plurality of sawtooth structures arranged continuously, each of the sawtooth structures including a first refractive surface and a second refractive surface which are intersected with each other, two ends of each of the sawtooth structures being respectively extended toward the light entrance and the light exit. The light source module provided by the present disclosure adopts the above-mentioned reflective device, the reflective device being transparent, the inner surface of the reflective device including the plurality of sawtooth structures arranged continuously.