Pressure sensing element (and safety apparatus) having intermediate layer with two functional layers

An apparatus comprising:

• a pressure sensing element including an intermediate layer having a structure in which at least two functional layers are stacked, a first electrode layer disposed on one surface of the intermediate layer and including a plurality of first electrode patterns, and a second electrode layer disposed on an opposing surface of the intermediate layer to overlap the first electrode layer with the intermediate layer between the first electrode layer and the second electrode layer, the at least two functional layers including a first functional layer and a second functional layer, the first functional layer is to face the plurality of first electrode patterns, and the second functional layer is to face the second electrode layer such that the second functional layer is between the first functional layer and the second electrode layer, wherein a thickness of the first functional layer varies based on pressure applied to the pressure sensing element, the thickness of the first functional layer is to linearly vary within a first strain percentage range of the first functional layer when the applied pressure is within a first pressure range, and the thickness of the first functional layer is to vary at a different rate within a second strain percentage range of the first functional layer when the applied pressure is equal to or greater than pressure in the first pressure range, wherein the first pressure range is a pressure amount that ranges from a first pressure to a second pressure, the first strain percentage range of the first functional layer is a strain percentage that ranges from a first strain percentage to a second strain percentage, and a thickness of the second functional layer varies based on pressure applied to the pressure sensing element, the thickness of the second functional layer is to linearly vary within a second strain percentage range of the second functional layer when the applied pressure is within a second pressure range, the thickness of the second functional layer is to vary at a different rate within a first strain percentage range of the second functional layer when the applied pressure is equal to or less than pressure in the second pressure range, and the thickness of the second functional layer is to vary at a different rate within a third strain percentage range of the second functional layer when the applied pressure is equal to or greater than pressure in the second pressure range, wherein the second pressure range is a pressure amount that ranges from a third pressure to a fourth pressure, the first strain percentage range of the second functional layer is a strain percentage that ranges from a third strain percentage to a fourth strain percentage, the second strain percentage range of the second functional layer is a strain percentage that ranges from the fourth strain percentage to a fifth strain percentage, and the third strain percentage range of the second functional layer is a strain percentage that is equal to or great than the fifth strain percentage, wherein the fifth strain percentage is greater than the fourth strain percentage, a maximum tolerable pressure that the first functional layer can withstand within the first pressure range is equivalent to a minimum amount of pressure within the second pressure range, wherein the maximum tolerable pressure within the first pressure range is the second pressure, and the minimum amount of pressure within the second pressure range is the third pressure, wherein the first strain percentage range of the first functional layer is greater than the second strain percentage range of the first functional layer, and wherein the second strain percentage range of the second functional layer is greater than the first strain percentage range of the second functional layer;
• a control unit configured to generate a control signal according to a change in a thickness of the intermediate layer;
• and
• an output unit configured to output the control signal.