Directional Lamp Beam Forming Optical System
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Solution Overview
Problem
Existing LED-based spot lighting technologies face challenges in achieving a combination of good color quality, beam control, and uniform illuminance while maintaining high efficacy and long lamp life, as they often suffer from poor color rendering index (CRI), excessive heat generation, and high manufacturing costs, making them unsuitable for applications like product displays and residential lighting.
Innovation Solution
A directional lamp design featuring a low-profile LED light source optically coupled with beam-forming optics, including a lens and a collecting reflector, where the LED source is positioned within 10% of the lens's focal length, and a light mixing diffuser is used to achieve a narrow beam with improved color mixing and reduced light losses, optimizing etendue and skew invariants to maximize efficacy and beam control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If LED devices are used as point light sources with collimating optics to achieve narrow beam patterns, then beam control is improved, but color rendering quality deteriorates
Solution Approach 1:
The patent segments the light source into multiple LED devices with different emission characteristics (white LEDs for beam formation and red LEDs for color compensation) arranged in a specific geometric pattern. This segmentation allows independent optimization of each LED type's function while achieving combined performance that neither could achieve alone.
Solution Approach 2:
The patent merges two previously separate approaches (white LED point source with collimating optics for narrow beam, and white LED with red LED combination for high CRI) into a single integrated light engine design where both white and red LEDs work together to simultaneously achieve narrow beam FWHM and high color rendering quality.
2Manufacturing precision
If white LED devices are combined with red LED devices to achieve high CRI, then color quality is improved, but beam control deteriorates due to large beam FWHM values
Solution Approach 1:
The patent applies local quality by positioning white LEDs and red LEDs at different locations within the light engine, with white LEDs optimized for directional beam formation and red LEDs optimized for color compensation. Each LED type operates in its optimal local zone, achieving both narrow beam and high CRI simultaneously.
Solution Approach 2:
The patent transitions from a single-point light source approach to a multi-point array configuration, adding spatial dimensionality to the light engine design. This allows different LED types to be distributed in three-dimensional space, enabling simultaneous optimization of beam formation and color mixing through geometric arrangement.
3Manufacturing precision
If a deep color-mixing cavity is used to achieve uniform illuminance and color, then color mixing is improved, but light losses increase due to cavity absorption
Solution Approach 1:
The patent extracts the color mixing function from a deep cavity structure and implements it through a compact light engine with optimized LED positioning and optical path design. This eliminates the need for multiple reflections in a deep cavity, achieving uniform color mixing with minimal light loss through direct optical paths.
4Illumination intensity
If a compound parabolic concentrator with small aperture is used to achieve narrow beam FWHM, then beam control is improved, but lamp size increases
Solution Approach 1:
The patent employs dynamic optical design where the light engine can be configured with adjustable parameters (LED positions, optical element geometries) to optimize performance for different beam FWHM requirements. This allows compact design while maintaining the ability to achieve narrow beam angles through optimized optical paths rather than oversized mechanical structures.
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 achieves a high CRI, narrow beam angle, and efficient light distribution, enhancing the lamp's efficacy and reliability while conforming to MR/PAR/R standards, allowing for compact size and effective heat dissipation, thus addressing the limitations of previous LED-based spot lighting solutions.
Implementation Method 1
a lens disposed at the exit aperture of the collecting reflector, the light source being positioned along an optical axis of the beam forming optical system at a distance from the lens that is within plus or minus ten percent of a focal length of the lens
Implementation Method 2
a reflector arranged to reflect light from the light source that misses the lens into the lens to contribute to the light beam
Implementation Method 3
a light mixing diffuser arranged to diffuse the light beam
Data Source
AI summary
A directional lamp comprises a light source, a beam forming optical system configured to form light from the light source into a light beam, and a light mixing diffuser arranged to diffuse the light beam. The light source, beam forming optical system, and light mixing diffuser are secured together as a unitary lamp. The beam forming optical system includes: a collecting reflector having an entrance aperture receiving light from the light source and an exit aperture that is larger than the entrance aperture, and a lens disposed at the exit aperture of the collecting reflector, the light source being positioned along an optical axis of the beam forming optical system at a distance from the lens that is within plus or minus ten percent of a focal length of the lens.