An optical disc with a first recording layer has first data pits that include 14T data pits formed thereon in compliance with DVD-ROM specifications. A first reflective film is formed on the first recording layer, whereby the first reflective film has the relationship of 2.3.ltoreq.Pw/Tf.ltoreq.14 between the 14T pit width and the first reflective film thickness. The disc also includes a second recording layer having a first surface and an opposed second surface, whereupon second data pits are formed on the first surface in compliance with BD-ROM specifications. A second semi-transparent reflective film is formed on the second recording layer, while a transparent layer having opposed third and fourth surfaces is formed over the second reflective film at the third surface, such that the fourth surface allows a laser beam to pass therethrough in reproduction from either the first or second data pits.

 
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< Electrostatic audio loudspeakers

> Mobile terminal having a plurality of displays

> Electret covered with an insulated film and an electret condenser having the electret

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