Apparatus including flexible vibration module

An apparatus, comprising:

• a vibration plate;
• a piezoelectric composite layer at a rear surface of the vibration plate, the piezoelectric composite layer being configured to vibrate the vibration plate;
• a first electrode layer in contact with an entire first surface of the piezoelectric composite layer;
• and
• a second electrode layer in contact with an entire second surface of the piezoelectric composite layer different from the first surface of the piezoelectric composite layer,
• wherein the piezoelectric composite layer includes:
• a plurality of vibration portions spaced apart from each other and each having a first surface and a second surface at least one of which is parallel with the rear surface of the vibration plate;
• and
• a plurality of flexible portions between the plurality of vibration portions, respectively, and each having a first surface and a second surface at least one of which is parallel with the rear surface of the vibration plate, and
• wherein each of the plurality of vibration portions and the plurality of flexible portions has a same height in a cross-sectional view.