Prismatic Light Guide for Homogeneous Elongated LED Output
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Solution Overview
Problem
Existing light guides for electrical devices using LEDs are bulky, inefficient in light distribution, and consume high energy due to the need for multiple LEDs, especially when insulation requirements necessitate a minimum distance, leading to impractical and non-homogeneous light output.
Innovation Solution
A light guide with an elongated output surface and a prism shape, made of a high-transmission material, divides incident light flux into three fluxes using refractive and reflective surfaces, ensuring homogeneous light distribution from a single LED while maintaining insulation distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If multiple LEDs are arranged next to each other to form an elongated LED, then the output surface has an elongated shape, but the electrical energy consumption becomes high
Solution Approach 1:
The input surface is divided into multiple faces (central face, first lateral face, second lateral face) that segment the incident light flux into three separate fluxes. Each face is optimized to direct light to specific regions of the output surface, achieving elongated light distribution from a single LED source.
Solution Approach 2:
The patent introduces a thickness dimension to the light guide body, creating a three-dimensional prism structure. The light flux is distributed through the thickness of the body via refraction and reflection at strategically angled faces, enabling elongated output without requiring multiple LEDs arranged in sequence.
2Stability of the object's composition
If the light guide has a generally trapezoidal shape with height greater than 2.5 times the width of the output surface, then the output flux is substantially homogeneous, but the light guide becomes relatively bulky
Solution Approach 1:
Different regions of the light guide body have different optical functions. The input surface features centrally-located and laterally-located faces with specific angle ranges, creating localized light distribution zones that collectively achieve homogeneous output flux without requiring excessive overall dimensions.
Solution Approach 2:
The patent optimizes the angular parameters of the input surface faces, specifying that the central face forms angles between 60-120 degrees with lateral faces. This parameter optimization enables effective light distribution in a more compact geometry while maintaining flux homogeneity.
3Stability of the object's composition
If dispersing materials are added to the light guide material, then the light distribution is improved, but the output flux intensity is reduced when the light guide has a height greater than a few millimeters
Solution Approach 1:
The patent replaces the use of dispersing materials (chemical/optical additives) with a geometric-optical system consisting of refraction and reflection at structured input surface faces. This mechanical/geometric approach distributes light effectively without the light absorption and scattering losses inherent in dispersing material systems.
4Reliability
If the input surface is arranged opposite the LED to capture light flux, then the output surface must be distant from the LED to meet insulation requirements, but this increases the light guide length and reduces light intensity
Solution Approach 1:
The light guide body provides continuous optical coupling between the input surface and output surface through controlled refraction and internal reflection. This continuous light guidance mechanism maintains high intensity even over the insulation distance required by electrical safety standards, preventing light intensity degradation.
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 a homogeneous and energy-efficient light output with reduced light loss, meeting insulation requirements and minimizing the number of LEDs needed.
Implementation Method 1
the incident light flux, emitted by the light-emitting diode and passing through the input surface, is divided, by refraction upon passing through the input surface, into three distinct light fluxes
Implementation Method 2
the external reflection faces including: a first external reflection face, which is associated with the first lateral face, and which is configured to reflect the first flux inside the light guide
Data Source
Figure 1a~1b
Figure 2
Figure 3a~3c
AI summary
This light guide (110) comprises a body (120) having a substantially planar output surface (112) and an input surface (122) configured to capture an incident light flux (F106) emitted by a light-emitting diode (106). The input surface (122) comprises a central face (124) straddling a median plane (M120) and, on each side of the median plane (M120), a first lateral face (131) and a second lateral face (132), such that the incident light flux (F106) is divided into three distinct light fluxes. The body (120) also comprises external reflection faces, which are each configured to reflect the light fluxes associated with each lateral face towards the output surface (112).