Light Collimator With Perpendicular Cavities for Glare Reduction
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Solution Overview
Problem
Conventional linear light emitting devices suffer from light leakage at high angles due to the interaction of extraction means with the light guide, leading to glare and inefficient light distribution, especially in applications like office environments.
Innovation Solution
An elongated light waveguide with perpendicular cavities and a diffuse reflective layer is used to extract light, reducing glare by preferentially reflecting high angles of incidence back into the waveguide and transmitting low angles, resulting in collimated light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If dots of paint are used as extraction means in the light guide, then light can be extracted from the light guide, but light leakage occurs at high angles causing glare
Solution Approach 1:
The patent applies local quality by using elongated cavities with specific aspect ratios (length-to-width ratio greater than 2) instead of uniform dot paint throughout the light guide. These strategically positioned elongated cavities preferentially extract light at low angles while maintaining high angle light within the guide, thereby reducing glare locally at the extraction sites without compromising overall light extraction efficiency
Solution Approach 2:
The patent changes the geometric parameters of the extraction structures from circular dots to elongated cavities with specific aspect ratios (cl/cw > 2). This parameter change fundamentally alters the light extraction characteristics, enabling angular selectivity where low angle light is extracted efficiently while high angle light is reflected back into the guide, thus eliminating glare
2Object-affected harmful factors
If elongated cavities are used to extract light, then light leakage is reduced, but the structure becomes more complex
Solution Approach 1:
The patent segments the light guide by incorporating multiple discrete elongated cavities distributed along its length rather than using continuous extraction mechanisms. Each cavity is independently formed with specific dimensions (length greater than twice the width), creating modular extraction zones that reduce light leakage while maintaining manufacturing simplicity through standard molding or machining processes
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 effectively reduces light leakage and maintains a substantial part of the outcoupled light within a cone of 65° or less, minimizing glare and ensuring more efficient light distribution.
Implementation Method 1
When light hits the paint, the light is substantially scattered in a Lambertian manner
Implementation Method 2
the light is substantially scattered in a Lambertian manner
Implementation Method 3
Light of LEDs is coupled into a light guide. Once being in a light guide, the light propagates in the confined volume
Implementation Method 4
By making holes in the light guide one can extract the light from the light guide
Data Source
Figure 1a~1c
Figure 2a~3a
Figure 3b~4
AI summary
The invention provides a light collimator (1) comprising (a) an elongated light waveguide (100) having a waveguide longitudinal axis (101), a waveguide length (wl), a waveguide width (ww) and a waveguide height (wh); the waveguide height (wh) defined by the height between a first waveguide surface (151) and a second waveguide surface (152), the waveguide (100) having an aspect ratio of the waveguide length (wl) and the waveguide width (ww) wl/ww > 1; the waveguide comprising a plurality of elongated cavities (110); each cavity (110) comprises a cavity longitudinal axis (111), a cavity length (cl), a cavity width (cw) and a cavity height (ch); each cavity having an aspect ratio of the cavity length (cl) and the cavity width (cw) cl/cw > 1, wherein the cavity longitudinal axes (111) of the plurality of cavities (110) are perpendicular to the waveguide longitudinal axis (101); and (b) a diffuse reflective layer (200) adjacent to the second waveguide surface. The invention further provides a lighting unit (2) using such collimator (1).