Hollow Light Guide Module Involving Mini Light-Emitting Diodes for Asymmetric Luminous Planar Illuminators

Abstract

Light-emitting diodes (LEDs) have numerous advantages. However, LEDs only offer a point light source. Therefore, transforming LEDs into planar light sources is a new objective in general lighting applications. Solid light guides have strong uniformity but are marred by their material absorption characteristics and weight. Hollow light guides constitute a solution to the weight problem but exhibit poor uniformity and necessitate sacrificing efficiency to enhance uniformity. To resolve the uniformity, weight, and efficiency problems simultaneously, we propose a hollow light guide architecture involving mini-LEDs with asymmetric luminous intensity. To develop this guide module, we first optimized the aspect ratio of the cavity and then modulated the light path by using varied angles of the reflection surface on the end wall of the module. We then designed a beveled reflection surface near the mini-LEDs to further enhance uniformity. An archetype of the proposed architecture for planar light source modules had a width and depth of 51.5 and 9.95 mm, respectively. Experimental results revealed a total efficiency of 83.9% and uniformity of 92.3%. The module weight was determined to be 215 g, which was 40% lighter than that of similarly sized solid light guide modules.

Mini-LEDs with Diffuse Reflection Cavity Arrays and Quantum Dot Film for Thin, Large-Area, High-Luminance Flat Light Source

“…For example, Ye et al proposed a hollow tube structure containing mini-LEDs with asymmetrical luminous intensity and designed a beveled reflective surface on the side of the mini-LEDs to achieve high efficiency and high uniformity. Moreover, they proposed a flat light source module without a light guide plate with a dot pattern and a completely printed diffuse reflection light guide plate on the bottom surface of the light source module to achieve high efficiency and high uniformity [ 34 , 35 ]. Ohno proposed an LED lighting module with a coaxial light conductor to achieve high efficiency and high wide-angle performance [ 36 ].…”

Revision of Threshold Luminance Levels in Tunnels Aiming to Minimize Energy Consumption at No Cost: Methodology and Case Studies

“…In Europe (EU28) there are more than 1.6 million km of illuminated streets that annually consume approximately 35 TWh) at a cost of $4 billion euro for the public authorities [2]. During the last decade there has been ongoing research activity focused on energy management using various types of renewable energy sources [3][4][5], on recycling [6], on safety [7][8][9][10], and a concentrated effort has been made for making street lighting systems sustainable [11][12][13][14][15][16][17][18][19] and environmentally friendly [20][21][22]. In addition, during the last few years, the issue of avoiding light pollution [23][24][25][26][27][28] has gained importance in technical reports [29] and expert discussions [30].…”

Luminous Intensity Field Optimization for Antiglare LED Desk Lamp without Second Optical Element

“…A hollow-type planar light source with reflecting, scattering, and multiple point light sources along at least one side plane was proposed to build a planar light source module [5]. A hollow light guide comprising LEDs with an asymmetric light field was proposed to transform an LED point light source into a planar light source without a light guide plate, so that it had 40% lower weight than a solid light guide module [6]. Another study developed a light guide plate with LEDs with an asymmetric light distribution and a light guide plate with a printed diffusion reflection on the bottom surface to achieve a circular large-area light source [7].…”