Emergency Exit Sign Light Guide Structure for Reflection Control
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Solution Overview
Problem
Existing emergency exit signs suffer from bright spots or light reflections due to the coupling area between the light guide and cover, reducing luminous efficacy and aesthetics.
Innovation Solution
The design of the light guide with varying thicknesses and total internal reflection surfaces prevents unwanted light leakage and reflections, ensuring efficient light transmission and aesthetically pleasing emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light guide with a coupling area between the light guide and cover is used, then light can be transmitted from the light source to the emission area, but light reflections and bright spots appear in the coupling area, reducing luminous efficacy and aesthetics
Solution Approach 1:
The patent converts the harmful light reflections into beneficial total internal reflections by designing the light guide with a specific refractive index and geometric configuration. The coupling area is engineered so that light rays that would normally reflect harmfully are instead guided through total internal reflection to reach the emission area efficiently, transforming the problematic reflection into a useful light guiding mechanism
Solution Approach 2:
The light guide is designed with varying thickness - thinner in the coupling area and thicker in the emission area. This local variation in geometry creates different optical properties in different regions: the thinner coupling area minimizes reflection losses while the thicker emission area enhances light output and aesthetics, allowing each region to optimize its local function
2Ease of manufacture
If the light guide has a uniform thickness design, then manufacturing is simpler, but light rays drift away in the connecting section and cause light leakage
Solution Approach 1:
The light guide features non-uniform thickness with a thinner coupling section and a thicker emission section. This local geometric variation serves multiple functions: it guides light rays effectively through the connecting section by controlling their propagation paths, prevents light leakage at the cover interface, and concentrates light in the emission area for enhanced output, all while maintaining manufacturing feasibility through standard molding techniques
3Volume of moving object
If the light guide is made thinner for a compact design, then the luminaire is more compact and aesthetically pleasing, but light transmission efficiency decreases
Solution Approach 1:
The light guide is designed with spatially varying thickness - thinner in the coupling area to maintain compactness and thicker in the emission area to ensure efficient light transmission. This local differentiation allows the luminaire to achieve a compact overall size while maintaining high luminous efficacy, as each section's thickness is optimized for its specific functional requirement
Solution Approach 2:
The patent addresses the size-efficiency tradeoff by transitioning from a uniform one-dimensional thickness to a three-dimensional variable thickness profile. This dimensional complexity allows the light guide to be thin where space is constrained (coupling area) while remaining thick where light transmission is critical (emission area), effectively resolving the contradiction between compactness and 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
The solution enhances light output efficiency, improves legibility of safety signs, and maintains a modern, compact, and aesthetically appealing appearance.
Implementation Method 1
This light reflection is reduced by total internal reflection. T Light is guided inside the light guide 11
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
The invention relates to an emergency exit sign 100 or a safety sign 100, which comprises a housing 130 extending along a longitudinal axis L, elongated light sources 120 consisting of at least one LED 121 and a circuit board 122, and a cover 114 which covers the housing 130 on one side, as well as a plate-shaped light guide 111 which is integrally connected to the cover 114. The light guide 111 and the cover 114 are integral components of a cover element 110, wherein the light guide 111 comprises at least one light coupling section 111A and a connecting section 111B, which is arranged downstream of the light coupling section 111A and to which the cover 114, connected to the light guide 111, is connected, and a light capture section 111C, which is arranged downstream of the connecting section 111B.It is essential here that in a cross-section perpendicular to the longitudinal axis L of the optical fiber 111, the thickness D of the light-capturing section 111C at the transition to the connecting section 111B is greater than the thickness d of the light-coupled section 111A at the transition to the connecting section 111B.