A novel opto-electromagnetic actuator coupled to the tympanic membrane

Chia Fone Lee, Chih Hua Shih, Jen Fang Yu, Jyh Horng Chen, Yuan Fang Chou, Tien Chen Liu*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

9 Scopus citations


A new type of electromagnetic vibration transducer designed to be placed onto the tympanic membrane was developed. The actuator consisted of two photodiodes, two permanent magnets, an aluminum ring, two opposing wound coils, a latex membrane and a Provil Novo™ membrane. An optic probe was designed to allow sound and light signals to enter the ear canal, thereby preventing the acoustic occlusion effect of traditional ear molds. Two light-emitting diodes were used for carrying the input signals. The corresponding photodiodes were used for receiving the light signals and generating currents in the actuator. The opto-electromagnetic vibration actuator was fabricated and tested using a Laser Doppler vibrometer. The actuator showed displacements of vibration between 30 and 1 nm from 300 to 6500 Hz and reduced in amplitude at higher frequencies. The average gain of the actuator with 140 μA on the umbo displacement was about 20 dB relative to 87 dBA at the distance of 6 cm from the tympanic membrane and 0 μA in actuator.

Original languageEnglish
Pages (from-to)3515-3518
Number of pages4
JournalJournal of Biomechanics
Issue number16
StatePublished - 05 12 2008


  • Actuator
  • Hearing aids
  • Opto-electromagnetic


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