Regular Paper

[OPTICAL REVIEW Vol. 21, No. 5 (2014) 655-658]
© 2014 The Japan Society of Applied Physics

Investigation of Light Extraction from Light Emitting Module Chip-on-Board

Svetlana LIPNITSKAYA1,2, Karim MYNBAEV1,2,3*, Lidiya NIKULINA2, Vladimir KRAMNIK2, Vladislav BOUGROV1,2, Alexey KOVSH1,2, Maxim ODNOBLYUDOV1,2, and Alexey ROMANOV1,2,3

1ITMO University, Kronverkskiy 49, Saint-Petersburg 197101, Russia
2Optogan Group, Tallinskoe 206, Saint-Petersburg 198205, Russia
3Ioffe Institute, Polytechnicheskaya 26, Saint-Petersburg 194021, Russia

(Received April 1, 2014; Accepted June 17, 2014)

A research has been carried out on the optimization of the shape of encapsulating cover to minimize optical losses in light-emitting modules fabricated with the “chip-on-board” (COB) technology. Optical properties of the components of a typical COB were taken into account including those of the substrate, light-emitting chips, encapsulating material and phosphor particles. Light losses were analyzed for various types of encapsulant surface structuring in an attempt to design an optical element with maximum light extraction efficiency. Calculations were complemented with experimental measurements. The results of the research showed that structuring the surface of the encapsulant can enhance light extraction by 10 to 15% for the material without phosphor particles and by 10 to 14% for the material with phosphor particles.

Key words: light extraction, light-emitting module, optical coating, chip-on-board

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