Large-area, uniform white light LED source on a flexible substrate

Abstract

This study demonstrates the flexible white LED structure with high lumen efficiency and uniform optical performance for neutral white and warm white CCT. Flip-chip LEDs were attached on a polyimide substrate with copper strips as electrical and thermal conduction paths. Yellow phosphors are mixed with polydimenthysiloxane (PDMS) to provide mechanical support and flexibility. The light efficiency of this device can reach 120 lm/W and 85% of light output uniformity of the emission area can be achieved. Moreover, the optical simulation is employed to evaluate various designs of this flexible film in order to obtain uniform output. Both the pitch between the individual devices and the thickness of the phosphor film are calculated for optimization purpose. This flexible white LED with high lumen efficiency and good reliability is suitable for the large area fixture in the general lighting applications.

Advances in Quantum-Dot-Based Displays

“…The commonly applied method is to combine the solid-state lighting and curved light guide; nevertheless, the curved light guide is so stiff that it is unsuitable to be bent numerous times, as required for flexible devices [84]. In 2015, Kuo et al [85] used the flip-chip, silicone-based anisotropic conductive adhesive, and phosphor film, which easily achieved the fabrication of a flexible lighting device. A uniform flexible LED, high-efficiency illumination, and a wide range of bending was achieved without deterioration of the total light output.…”

Modulation of the two-dimensional electron gas channel in flexible AlGaN/GaN high-electron-mobility transistors by mechanical bending

“…Mechanically flexible electronic and photonic devices based on group-III-nitride (III-N) thin films have been developed for potential system applications of wireless communication, radars, flexible displays, electro-mechanical sensing, and energy harvesting. [1][2][3][4] Most of these studies focused on the mechanical bendability of the structure while minimizing the performance degradation of the devices, which is important in many applications. However, flexible devices made of III-N thin films have implications surpassing merely the ability to fabricate bendable devices.…”

Effect of Different Bonding Materials on Flip-Chip LED Filament Properties

“…As a new generation of light source, the light-emitting diode (LED) has many advantages, such as energy saving, environmental protection, and no radiation emission [1][2][3]. With the growing demand of LEDs, the white LED has been industrialized [4,5]. Flip-chip LED (FC-LED) filament bulbs are gradually replacing incandescent lamps, with the advantages of lower working voltage, less power consumption, and higher luminous efficiency.…”