Side Emitting LED Light Guide Device with Segmented Optical Paths
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Solution Overview
Problem
Existing edge-illuminating light guide systems in consumer electronics are inefficient in providing uniform illumination from side edges and consume excessive power, failing to optimally direct light from side emitting LEDs.
Innovation Solution
An edge-illuminating light guide device comprising an ingress light guide with a narrow inlet and a wide outlet connected to an LED, and an egress light guide with selectively coated faces to restrict light emission, allowing directional light transmission through uncoated surfaces, fabricated from polycarbonate to maximize light emission and minimize power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional light guide systems are used to provide illumination from side edges, then illumination coverage is achieved, but power consumption is excessive and illumination uniformity is insufficient
Solution Approach 1:
The light guide is divided into two distinct segments: an ingress light guide with a narrow light inlet that receives light from the LED, and an egress light guide with a wide light outlet that emits light. This segmentation allows each portion to be optimized for its specific function, improving overall system efficiency and illumination uniformity while reducing power consumption.
Solution Approach 2:
Different portions of the light guide are given different properties: the ingress light guide has a narrow inlet for efficient light capture, while the egress light guide has a wide outlet for uniform light distribution. The tapered geometry creates local variations in light path length and emission area, achieving uniform illumination across the surface.
2Illumination intensity
If light guide surfaces are left uncoated to maximize light emission, then light transmission is high, but light emission occurs in unwanted directions
Solution Approach 1:
The light guide surfaces are selectively coated: the front and back faces are coated with a composition to restrict light emission, while the side edges remain uncoated to allow light transmission. This local differentiation of surface properties enables precise directional control, allowing light to exit only through the desired side edges while maintaining high transmission efficiency.
Solution Approach 2:
A composition is applied to specific faces of the egress light guide that changes the optical properties of those surfaces. The coated faces become light-restricting, while uncoated side edges maintain their light-transmitting properties, achieving directional control without sacrificing overall light transmission.
3Use of energy by moving object
If a narrow light inlet is used to connect LED to light guide, then power consumption is reduced, but light transmission efficiency decreases
Solution Approach 1:
The light guide system is segmented into an ingress portion with a narrow light inlet optimized for LED coupling, and an egress portion with a wide light outlet optimized for light distribution. This segmentation allows the narrow inlet to minimize power consumption while the tapered geometry ensures efficient light transmission through the transition to the wider egress portion.
Solution Approach 2:
The light guide employs a tapered three-dimensional geometry that transitions from a narrow inlet to a wide outlet. This dimensional change along the length of the light guide compensates for the initial narrow coupling, maintaining light transmission efficiency while allowing the LED to operate at lower power levels.
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 device achieves efficient directional lighting with reduced power consumption by guiding light through selected faces, effectively illuminating large surfaces with uniform brightness and controlled brightness levels, while maintaining low power usage.
Implementation Method 1
An ingress light guide having a narrow light inlet end operatively connected to an LED and a wide light outlet end, and an egress light guide integrally joined with, and in illuminating communication with, the ingress light guide
Implementation Method 2
whereby one or more surfaces of the light guide are coated with a composition to restrict light emission therethrough, thereby allowing light to selectively pass through the uncoated surfaces
Data Source
AI summary
An edge-illuminating light guide device works with a consumer electronic to provide directional lighting to efficiently emit illumination from the sides of a screen, while maximizing light emission and minimizing power usage. The device utilizes two light guides that join to direct light from a light source across a directional path from the sides of the device. An ingress light guide has a flat, triangular shape that tapers from a narrow light inlet end to a wide light outlet end. The narrow light inlet end connects to a light source. An egress light guide is defined by a flat, rectangular shape. The egress light guide integrally joins with, and is in illuminating communication with the ingress light guide. A composition coats one of the faces of the egress light guide to prevent passage of the light; thereby serving as a color filter. The device is fabricated from a polycarbonate.