Light Transmissive Solid for Optical Integrating Volume
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Solution Overview
Problem
Existing solid state lighting fixtures with optical integrating cavities face efficiency issues due to contamination from dirt or debris and internal reflection within LED packages, which reduces light output and requires larger apertures to prevent direct emissions, compromising the uniformity and efficiency of the lighting.
Innovation Solution
A light transmissive solid with a higher refractive index than the ambient environment is used to fill the optical integrating volume, closely conforming to the LED emitters to reduce internal reflections and prevent contamination, while a reflective mask and total internal reflection are employed to control light emission and enhance aperture size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an optical integrating cavity filled with air is used, then light mixing is achieved, but internal reflection at the LED package surface traps light and reduces efficiency
Solution Approach 1:
The patent changes the refractive index parameter of the medium filling the optical integrating cavity from air (low refractive index) to a light transmissive solid with higher refractive index. This parameter change reduces the refractive index mismatch at the LED package interface, minimizing internal reflection and improving light extraction efficiency without requiring complex cavity structures.
Solution Approach 2:
The light transmissive solid acts as an intermediary material between the LED package and the optical cavity environment. It serves as a refractive index matching layer that facilitates light extraction from the LED package while maintaining the optical integrating function, effectively mediating the optical interaction between the LED and the cavity.
2Illumination intensity
If the cavity is open to allow light emission, then light output is achieved, but contamination from dirt or debris compromises diffuse reflectivity and reduces efficiency
Solution Approach 1:
The light transmissive solid forms a protective enclosure (shell) around the optical integrating cavity while remaining optically transparent. This shell prevents contamination from dirt or debris from entering and compromising the diffuse reflectivity of the cavity interior, while still allowing integrated light to pass through to the aperture for light output.
Solution Approach 2:
The light transmissive solid creates an optical window that replicates the function of an open aperture for light emission while providing the protective benefits of a closed structure. It allows light to pass through as if the cavity were open, but simultaneously protects the interior from contamination.
3Stability of the object's composition
If a mask with relatively large size is used to prevent direct emissions, then uniform light output is improved, but the optical aperture becomes small and reduces light extraction
Solution Approach 1:
The patent changes the refractive index parameter of the cavity filling material, which modifies the optical path and light propagation characteristics within the cavity. This enables the use of a smaller mask size while maintaining uniform light output, as the altered optical parameters compensate for the reduced aperture area and improve overall light extraction efficiency.
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 configuration improves light extraction efficiency, maintains uniform light distribution, and prevents contamination, resulting in a more effective and efficient lighting solution with reduced hot spots and increased light output.
Implementation Method 1
a reflective mask and total internal reflection are employed to control light emission and enhance aperture size
Implementation Method 2
A light transmissive solid with a higher refractive index than the ambient environment is used to fill the optical integrating volume, closely conforming to the LED emitters to reduce internal reflections
Data Source
AI summary
An exemplary general lighting fixture includes an assembly forming an optical integrating volume for receiving and optically integrating light from one or more solid state light emitters and for emitting integrated light. The assembly includes a reflector having a diffusely reflective interior surface defining a substantial portion of a perimeter of the integrating volume. A light transmissive solid fills at least a substantial portion of the optical integrating volume. A light emitter interface region of the solid, for each solid state light emitter, closely conforms to the light emitting region of the respective emitter. A surface of the transmissive solid conforms closely to and is in proximity with the interior surface of the reflector. The transmissive solid also provides a light emission surface, at least a portion of which forms a transmissive optical passage for emission of integrated light, from the volume, in a direction facilitating a general lighting application.