Proximity sensor

A proximity sensor comprising:

• a circuit board having a first bonding pad area and a second bonding pad area;
• a light-emitting element and a light-receiving element which are apart from each other and mounted on the circuit board;
• a light barrier disposed between the light-emitting element and the light-receiving element;
• molding portions surrounding the light-emitting element and the light-receiving element;
• and
• a transparent board disposed on the molding portions and configured to form an air gap with the light-receiving element,
• wherein the light-receiving element comprises:
• a substrate having a light sensing area and a temperature sensing area and comprising a piezo electric material;
• a first input electrode and a first output electrode which are aligned in the light sensing area and apart from each other with a first delay gap between the first input electrode and the first output electrode;
• a sensing film overlapping the first delay gap and covering at least some portions of the first input electrode and the first output electrode;
• and
• a second input electrode and a second output electrode which are aligned in the temperature sensing area and apart from each other with a second delay gap between the second input electrode and the second output electrode,
• wherein the second delay gap is exposed to air.