Abstract: The present invention provides a time-reversal-based impact-localization and haptic-feedback method for touch panels. Firstly, a plate model for an elastic plate and the impulse responses thereof are constructed according a plate theory. Next, a mathematical model is established according to the impulse responses and a time-reversal approach. When an impact force hits the elastic plate, the touched point on the elastic plate generates a touch signal, and the touch signal is received by at least a sensor at the corner of the elastic plate. The touch signal is converted into a time-reversal signal according to the mathematical model by a simulator. The time-reversal signal is reversed to the touched point for simulating reversal vibration waves of the time-reversal signal on the elastic plate, and locating the touched point.

Abstract: A piezoelectric panel speaker and an optimal method of designing the same is disclosed. In the structure of the speaker, at least one piezoelectric plate attached at a surrounding frame supports a diaphragm inside the surrounding frame. A spacer is inserted between the piezoelectric plate and the diaphragm. The structure of the piezoelectric plates fixed at the surrounding frame improves the speaker performance within the low frequency range. The finite element method is employed to build a mathematical model to simulate the sound pressure loading of the piezoelectric panel speaker. Also, the simulated annealing method is employed to approach the optimal design parameters of the speaker structure.

Abstract: A piezoelectric panel speaker and an optimal method of designing the same is disclosed. In the structure of the speaker, at least one piezoelectric plate attached at a surrounding frame supports a diaphragm inside the surrounding frame. A spacer is inserted between the piezoelectric plate and the diaphragm. The structure of the piezoelectric plates fixed at the surrounding frame improves the speaker performance within the low frequency range. The finite element method is employed to build a mathematical model to simulate the sound pressure loading of the piezoelectric panel speaker. Also, the simulated annealing method is employed to approach the optimal design parameters of the speaker structure.

Abstract: The present invention provides a time-reversal-based impact-localization and haptic-feedback method for touch panels. Firstly, a plate model for an elastic plate and the impulse responses thereof are constructed according a plate theory. Next, a mathematical model is established according to the impulse responses and a time-reversal approach. When an impact force hits the elastic plate, the touched point on the elastic plate generates a touch signal, and the touch signal is received by at least a sensor at the corner of the elastic plate. The touch signal is converted into a time-reversal signal according to the mathematical model by a simulator. The time-reversal signal is reversed to the touched point for simulating reversal vibration waves of the time-reversal signal on the elastic plate, and locating the touched point.

Abstract: A piezoelectric panel speaker and an optimal method of designing the same is disclosed. In the structure of the speaker, at least one piezoelectric plate attached at a surrounding frame supports a diaphragm inside the surrounding frame. A spacer is inserted between the piezoelectric plate and the diaphragm. The structure of the piezoelectric plates fixed at the surrounding frame improves the speaker performance within the low frequency range. The finite element method is employed to build a mathematical model to simulate the sound pressure loading of the piezoelectric panel speaker. Also, the simulated annealing method is employed to approach the optimal design parameters of the speaker structure.

Abstract: A digital volume controller and a control method thereof are provided. The digital volume controller includes an adjuster, a D flip-flop and a processor. The adjuster outputs a first signal and a second signal according to a rolling direction of the adjuster. There is a phase difference between the first signal and the second signal. The D flip-flop includes a clock terminal coupled to the first signal, a D terminal coupled to the second terminal and a Q terminal coupled to a third signal. When the first signal generates an enabling trigger, the processor generates a volume control signal according to a logic level of the third signal.

Abstract: The present invention provides a key cap with a multiple-layer structure for use with a push button switch which having a plunger device. The key cap has a first portion formed by a first material and a second portion formed by a second material. The first portion includes at least one bearing portion connected to the plunger device. The second portion covers the first portion and includes a contact surface for bearing an external force exerted on the cap. The second portion has a thickness smaller than that of the first portion since the strength of the second material is higher than that of the first material.