Light Guide Prism Entrance Facets Homogeneous Illumination
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Solution Overview
Problem
Existing light guides for electrical devices with elongate indicator lights face challenges of high energy consumption due to multiple LEDs and bulkiness, with limited light intensity and homogeneity when using a single LED, and require significant isolation distances that increase size and material costs.
Innovation Solution
A light guide with a prism-shaped body made of insulating material having a refractive index of 1.4 to 1.6 and high light transmission, featuring a symmetrical design with angled entrance surfaces to divide light flux into three paths, reflected by external faces to achieve homogeneous light distribution from a single LED, using a synthetic polymer like polycarbonate or acrylic polymethyl methacrylate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs are arranged along the axis of width to form an elongate indicator light, then the light distribution along the exit surface is improved, but the energy consumption increases
Solution Approach 1:
The entrance surface is divided into multiple planar facets (first lateral face, second lateral face, third lateral face) that segment the incident light flux into different directional paths. Each facet redirects light toward specific regions of the exit surface, achieving homogeneous illumination along the elongate axis using a single LED source instead of multiple LEDs.
2Illumination intensity
If the light guide has a height greater than 2.5 times the width of the exit surface to achieve homogeneous output flux through multiple reflections, then the light distribution is improved, but the device becomes bulky
Solution Approach 1:
Instead of achieving light redistribution through vertical height (thickness dimension) via multiple internal reflections, the invention uses angular segmentation of the entrance surface facets to redirect light horizontally across the exit surface width. This transforms the problem from a vertical dimension solution to a horizontal angular distribution solution, reducing the required height while maintaining homogeneous output.
3Illumination intensity
If dispersing materials are added to the light guide material to improve light distribution, then the homogeneity is improved, but the light transmission coefficient decreases
Solution Approach 1:
The invention replaces the optical mechanism of light scattering through dispersing materials with a geometric optical mechanism using planar facets at the entrance surface. The facets deterministically redirect light rays through refraction and reflection based on their angular geometry, achieving homogeneous distribution without the random scattering that would absorb or trap light, thus maintaining high transmission coefficients.
4Use of energy by moving object
If a single LED is used to reduce energy consumption, then the energy efficiency is improved, but the light flux distribution along the elongate exit surface becomes insufficient
Solution Approach 1:
The invention changes the geometric parameters of the entrance surface by introducing multiple planar facets with specific angular orientations. These parameter changes in surface geometry enable a single LED to illuminate the entire elongate exit surface by systematically directing light at different angles to cover the full width, replacing the need for multiple LED sources.
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 enables efficient, homogeneous light distribution over a longer exit surface with reduced energy consumption and minimal material thickness, maintaining isolation distances while reducing LED count and guide bulkiness.
Implementation Method 1
the first lateral face, which is interposed between the central face and the second lateral face, configured such that the incident light flux emitted by the light-emitting diode and passing through the entrance surface is divided, by refraction upon passing the entrance surface, into three distinct light fluxes
Implementation Method 2
the body also comprises, on each side of the median plane, external reflecting faces, which are interposed between the exit surface and the entrance surface, each external face being associated with a respective lateral face and being configured to reflect the portion of the light flux associated with the corresponding lateral face toward the exit surface
Data Source
AI summary
The light guide (110) comprises a body (120) having a substantially plane exit surface (112) and an entrance surface (122) configured to capture an incident light flux (F106) emitted by a light-emitting diode (106). The entrance surface (122) comprises a central face (124) astride a median plane (M120) and, on each side of the median plane (M120), a first lateral face (131) and a second lateral face (132), so that the incident light flux (F106) is divided into three distinct light fluxes. The body (120) further comprises external reflecting faces, each configured to reflect light fluxes associated with each lateral face toward the exit surface (112).