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Balancing Visual Comfort and Efficiency in Indoor LED Lighting: Diffusion, Cut-Off Angle, and Thermal Management

Author(s)

Haozhan Li1, Jingyi Zhang2

Affiliation(s)

1Department of Physics, Hong Kong Baptist University, Hong Kong, China 2Northwest Normal University, Lanzhou, Gansu, China

Abstract

This paper looks at how to balance visual comfort and efficiency in indoor LED luminaires, focusing on diffusion, cut-off angle, and heat management. A diffuser smooths the emitting surface but usually costs about 5-15% light output. Adding a cut-off ( θc) to block high_angle light also helps with glare (UGR).Keeping the LED junction temperature under ~85°C helps keep CCT and light output stable. For learning and office environments, moderate diffusion with a θc of approximately 30–40° is recommended, combined with a simple heat sink , to achieve a balance between UGR and efficiency.

Keywords

LOR; Light Output Ratio; θc, Cut-Off Angle; UGR; Unified Glare Rating; Tj; LED Junction Temperature; CCT; Correlated Color Temperature.

References

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