Optical Element With Longitudinal Lightguides for Uniform Luminance
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Solution Overview
Problem
Existing lighting systems face challenges in achieving uniform luminance while being cost-efficient and easy to assemble, particularly in office luminaires with small exit windows, as current solutions are either costly or inefficient.
Innovation Solution
An elongated optical element with longitudinal and transverse extensions, featuring central portions and aligned lightguides with longitudinal jags, enhances luminance uniformity by reflecting light to dark areas, and can be integrated with lenses and a cover to improve light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If MLO cover and diffusive foil or diffusive reflector are used, then luminance uniformity is improved, but cost increases and efficiency decreases
Solution Approach 1:
The patent merges the light-diffusing function and the light-guiding function into a single integrated optical element. The diffuser plate with embedded lightguides eliminates the need for separate diffusive foils or reflectors, reducing component count, assembly complexity, and cost while maintaining luminance uniformity.
Solution Approach 2:
The lightguides act as intermediary elements that capture light from the LED sources and transport it to the edges of the diffuser plate. This intermediary mechanism enables uniform light distribution without requiring expensive additional diffusive layers or reflectors.
2Illumination intensity
If MLO cover and diffusive foil or diffusive reflector are used, then luminance uniformity is improved, but efficiency decreases
Solution Approach 1:
By combining the diffusing and light-guiding functions into one element, the patent eliminates intermediate optical interfaces that would cause light loss. The integrated design reduces reflection losses and absorption losses that occur when light passes through multiple separate components.
3Ease of manufacture
If PCS cover with lenses is used, then cost efficiency and ease of assembly are improved, but luminance uniformity deteriorates
Solution Approach 1:
The patent applies local quality by creating lightguides with specific optical properties at the edges of the diffuser plate. These lightguides have total internal reflection surfaces and diffusing surfaces that are locally optimized to redirect light uniformly across the exit window, addressing the non-uniformity issue of PCS covers.
Solution Approach 2:
The lightguides serve as intermediary structures that modify the light pattern from the LED sources before it reaches the exit window. They capture light in specific zones and redistribute it to create uniform luminance, bridging the gap between the point-source LEDs and the diffuse output.
4Ease of operation
If PCS cover with lenses is used, then ease of assembly is improved, but luminance uniformity deteriorates
Solution Approach 1:
The integration of lightguides directly into the diffuser plate structure eliminates the need for separate assembly steps for mounting diffusive foils or reflectors. The lightguides are molded as integral parts or attached during the same assembly process, maintaining ease of assembly while achieving uniform luminance.
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 solution provides improved luminance uniformity and efficiency, meeting office compliance requirements while being cost-effective and easy to assemble, with enhanced light distribution and symmetrical patterns.
Implementation Method 1
The first surface of the first lightguide comprises at least one longitudinal jag being substantially parallel to the longitudinal extension of the optical element... the beam of light emitted from the light source is reflected by the longitudinal jag thus improving luminance uniformity
Data Source
AI summary
The present invention relates to an elongated optical element (1) for a lighting system (100) having a longitudinal extension and a transverse extension being substantially perpendicular to the longitudinal extension. The optical element (1) has a central portion (2) having a first edge (2′) and a second edge (2″) being arranged substantially parallel to each other and to the longitudinal extension of the optical element (1). The optical element (1) further comprises at least a first lightguide (3) arranged at the first edge (2′) of the central portion (2), the optical element (1) having a first surface (4) facing at least one light source (112) of the lighting system (100), and a second surface (4′) being opposite to the first surface (4). The first surface (4) of the first lightguide (3) comprises at least one longitudinal jag (5) being substantially parallel to the longitudinal extension of the optical element (1).