Design of Micro-Lens Array Film in Organic Light-Emitting Diodes for Display and Lighting Applications
Date Issued
2015
Date
2015
Author(s)
Wu, Sheng-Jung
Abstract
ABSTRACT Owing to its fast response time, wide color gamut, light weight and flexible feasibility, organic light-emitting diode (OLED) is considered as the next generation display and lighting devices. However, due to its multi-layered structures and total internal reflection, most of the lights are confined within the OLED structure, limiting the out-coupling efficiency. It is a common method to improve the out-coupling efficiency through destroying total internal reflection by applying micro-lens array films (MLAFs) on OLED. In this thesis, we analyze the influence of out-coupling efficiency by the base angle and height of conical micro-lens array film (CMLAF). We found that the out-coupling efficiency can be maximum improved when while the height of CMLAF is equal to the radius of CMLAF, among the enhancement ratio can be 42.16% while the base angle is 70°. We also add the black matrix in our simulation model according to the OLED products in the market. We found the enhancement ratio become helpless after adding the black matrix in OLED. To solve the problem that the lights are absorbed by black matrix, we collimate the lights by arranging the internal micro structure in OLED. Besides, we attaching spherical, pyramidical, trapezoidical and conical macro-lens on the substrate of OLED, then the substrate mode can be out-coupled maximum and the illumination area can also be larger. For example of attaching spherical macro-lens, the enhancement ratio is 133.2% and the illumination area is 32.4 times compared to the bare OLED. There are different angular intensity profiles for different geometries of macro-lens, which can be used for different lighting application.
Subjects
OLED
micro-lens
OLED display
OLED lighting
Type
thesis
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