• Journal of Satellite, Information and Communications
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• v.8 no.2
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• pp.1-5
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• 2013

Recently, the spread of a variety of electronic card is using as credit cards, transportation cards, passports, driver's licenses, public phone card, and etc. LED smart cards need to raise application technique because variety of LED smart cards increasing supply and usage. in this paper, we propose a LED smart card contained inside the card that piezoelectric method flexible Ultra-thin speaker. and a melody flows when User using the LED smart card.. Therefore we are verified to useful through develop to electronic card that was designed system circuit and implemented circuit add in ultra-thin flexible Speaker based on piezoelectric.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.4
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• pp.333-336
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• 2017

A speaker diaphragm generates a divided vibration. The influence of the break-up mode is sufficient to cause a shape change in the diaphragm. In this paper, is widely used in ultra-thin multi-media devices, including smart phones is the advance guard of the IT sector, the micro-speakers and its target. Micro-speakers are different from general speakers. The plate has structural form and space constraints. In particular, they utilize a closed-type drive space. It is difficult to provide cooling for the auxiliary suspension structure because of the heat generated in the moving coil. The present study considered the relationship between the break-up mode and the heat transfer of the diaphragm. An experiment was conducted in two stages to compare the embodiment of the break-up mode and heat transfer in a certain frequency range. The changes in the heat were determined through measurements and thermal imaging of the break-up mode. The break-up mode tendency of the diaphragm could be rapidly predicted based on the imaging results using the thermal imaging camera. This will help in the optimal design of micro-speakers.