Speckle noise reduction in the laser mini-projector by vibrating diffuser

Jui-Wen Pan, Chi Hao Shih

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


We proposed a design for a laser mini-projector with a low speckle contrast value and high contrast ratio that maintains system efficiency. The key design is that two diffusers are located in the two sides of the light tunnel. By vibrating the 30 × 30 diffuser under 100 Hz, the speckle contrast value can be decreased to 2.32% which is invisible to the human eye. Considering the trade-off issue of optical efficiency and speckle noise, the most suitable arrangement with circular diffusers is '30 × 30H, 5 × 5. The vibration direction is at the long side of the light tunnel.

Original languageEnglish
Article number045606
Pages (from-to)1-5
Number of pages5
JournalJournal of Optics (United Kingdom)
Issue number4
StatePublished - Apr 2017


  • illumination system
  • laser projector
  • speckle


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