Lighting Device Subarea Segmentation for Optical Decoupling
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Solution Overview
Problem
Conventional lighting devices with incoherent light sources, such as LED chips, suffer from significant light loss due to reflection, which is often compensated by increasing radiation power, leading to higher energy consumption and thermal stress, as the approximation of a light source to a point source is not effective in managing the complex radiation characteristics of these sources.
Innovation Solution
The lighting device divides the radiation-emitting area of the incoherent light source into subareas, with each subarea assigned a light ray or light ray bundle, and an optical element with a decoupling surface is shaped to ensure that the angle of incidence is less than the total reflection angle, preventing total reflection and allowing more than half of the light to be directly decoupled, thereby increasing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the light source is approximated to a point light source and the optical element is shaped accordingly, then the device complexity is reduced, but the radiation efficiency deteriorates due to substantial light loss from total reflection
Solution Approach 1:
The radiation-emitting area of the light source is divided into multiple subareas, with each subarea assigned to a specific light ray or light ray bundle. This segmentation allows for precise tracking and optimization of light paths from different regions of the source, enabling the optical element to be shaped to prevent total reflection for each subarea's light rays while maintaining manageable design complexity.
2Illumination intensity
If the radiation power of the light source is increased to compensate for reflection losses, then the light output is improved, but the energy consumption and thermal stress increase
Solution Approach 1:
The invention converts the harmful effect of total reflection into a beneficial outcome by shaping the optical element to specifically prevent total reflection for light rays from different subareas. By addressing the root cause of light loss through geometric optimization rather than increasing power, the system achieves higher light output efficiency without proportionally increasing energy consumption or thermal stress.
3Illumination intensity
If the radiation power of the light source is increased to compensate for reflection losses, then the light output is improved, but the thermal stress on the light source increases
Solution Approach 1:
The invention converts the harmful effect of total reflection into a beneficial outcome by shaping the optical element to specifically prevent total reflection for light rays from different subareas. By addressing the root cause of light loss through geometric optimization rather than increasing power, the system achieves higher light output efficiency without proportionally increasing energy consumption or thermal stress.
4Ease of manufacture
If the optical element is adapted to point light source approximation, then the manufacturing is simplified, but the adaptability to incoherent light sources with complex radiation characteristics deteriorates
Solution Approach 1:
The radiation-emitting area is segmented into subareas, each with assigned light rays that have specific radiation powers and emission directions. This segmentation enables the optical element to be adapted to the complex radiation characteristics of incoherent light sources by optimizing for each subarea while maintaining overall manufacturability through systematic design approaches.
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 approach significantly enhances radiation efficiency by ensuring that a substantial fraction of the light, preferably over 50%, is decoupled without total reflection, reducing energy consumption and thermal stress, and allows for a more effective adaptation to the broader radiation characteristic of incoherent light sources.
Implementation Method 1
the angle of incidence on the decoupling surface is smaller than the total reflection angle assigned to the decoupling surface, the radiation power of these light rays collectively being greater than a predetermined fraction q of the total radiation power P
Data Source
AI summary
The invention relates to a lighting device comprising a light source (1) that emits incoherent light with a total radiation power P and has a radiation-emitting area (S) divided into a plurality of subareas (Si), wherein assigned to each subarea (Si) is a light ray (2) having a radiation power Pi and the sum of the radiation powers Pi is equal to the total radiation power P, and disposed after said light source (1) is an optical element (4) having a decoupling surface (5) and a total reflection angle (θc) assigned to said decoupling surface (5), said decoupling surface (5) being shaped so that at least for a portion of said light rays (2) the angle (α) of incidence on said decoupling surface (5) is smaller than the total reflection angle (θc), and the radiation power of said light rays collectively is greater than a predetermined fraction, equal to at least 50%, of the total radiation power P.