Analysis of light out-coupling from microlens array

Purushottam Kumar, Aniruddh Khanna, Seung Young Son, Jae Seok Lee, Rajiv K. Singh

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Microlens array has been known to be effective in enhancing the out coupling efficiency of LEDs, OLEDs and other thin film light emitting devices. However, mechanism of efficiency enhancement by use of microlens arrays is still ambiguous, apart from suggestions that it leads to randomization of photons. We have studied the photon dynamics in the presence of microlens arrays and the effect of various parameters e.g. microlens contact angle, absorption and substrate refractive index using ray tracing simulations. Microlens array leads to extraction of a portion of photons outside the escape cone at the cost of reduced extraction from within the escape cone. The reduced extraction from within the escape cone is compensated by multiple reflections from the back surface. Increase in microlens contact angle reduces the number of reflections required for out-coupling hence reducing the absorption in the device.

Original languageEnglish
Pages (from-to)4279-4282
Number of pages4
JournalOptics Communications
Issue number19
StatePublished - 1 Sep 2011
Externally publishedYes


  • Light extraction
  • Microlens array
  • Ray tracing
  • light out-coupling


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