A pressure sensing pattern layer is formed on a substrate and comprises a plurality of pressure sensing electrodes. Each of the pressure sensing electrodes comprises a plurality of protruding portions. The protruding portions are formed from a transparent conductive line which is bent zigzag. Each of the pressure sensing electrodes is electrically connected to a Wheatstone bridge circuit through a first conductive line and a second conductive line. A resistance of each of the pressure sensing electrodes is an element of the Wheatstone bridge circuit. When any of the pressure sensing electrodes is touched, a variation of the resistance of the touched pressure sensing electrode is detected by the Wheatstone bridge circuit.