Improving the brightness and daylight contrast of organic light-emitting diodes

V. Vaenkatesan, R.T. Wegh, J.P. Teunissen, Johan Lub, C.W.M. Bastiaansen, D.J. Broer

Research output: Contribution to journalArticleAcademicpeer-review

25 Citations (Scopus)
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For most applications of displays based on org. light-emitting diodes (LEDs), it is desirable to have good daylight contrast in combination with a high intensity of emitted light. The conventional approaches to enhance the daylight contrast, using a black cathode or circular polarizers, result in a significant loss of light emitted by the LED. A rather novel approach to enhance daylight contrast while keeping loss of emitted light to a min. is the introduction of a chiral-nematic film in the device. This approach leads to an increase in light efficiency by a factor of 1.8 (with respect to circular polarizers) with some loss in daylight contrast values within the reflection band of the chiral-nematic film. Outside the reflection band, however, the contrast approaches infinity
Original languageEnglish
Pages (from-to)138-142
Number of pages5
JournalAdvanced Functional Materials
Issue number1
Publication statusPublished - 2005


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