Flexible electrostatic actuator

An electrostatic actuator comprising:

• a base including a first electrode;
• a flexible membrane including at least two material layers of different materials in contact with each other, at least one of the material layers including a second electrode electrically isolated from the first electrode;
• a gap separating the flexible membrane from the base;
• the flexible membrane including,
• a fixed end connected to the base, and
• a free end opposite the fixed end and spaced apart from the base;
• said free end of the flexible membrane configured to move relative to the base under an electrostatic force;
• and
• said second electrode having at least first and second portions separated by a third portion and
• in combination the first, second, and third portions defining a first step and a second step provided in a vicinity of said fixed end, and in combination forming a reduced gap space between the base and the flexible membrane, when no pull down voltage is applied, and thereby to reduce a pull-down voltage needed to pull down the flexible membrane from an open no applied voltage position to a closed position,
• wherein
• said first step is adjacent to the fixed end and said second step is adjacent to the first step,
• the first step is closer to the fixed end than the second step,
• the first portion comprises said fixed end connected to the base, and
• the third portion is separated from the base by the reduced gap space.