Vibration Device Flexural Rigidity and Mass Member Design
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Solution Overview
Problem
The reduction in size and thickness of vibration devices leads to a decrease in vibration strength, making them less effective for notification purposes in portable electronic devices.
Innovation Solution
A vibration device design that incorporates a second elastic plate with higher flexural rigidity than the first elastic plate, along with a mass adding member and a circuit section, to enhance vibration strength while maintaining a reduced size and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a piezoelectric element is used to generate ultrasonic vibrations, then high-frequency vibrations can be generated, but the element is prone to breakdown due to resonance at specific frequencies
Solution Approach 1:
A magnetic drive system is introduced as an intermediary to generate ultrasonic vibrations. The magnetic drive includes a vibration generation coil and a magnetic drive element, where the coil generates a magnetic field that drives the magnetic element to vibrate at ultrasonic frequencies. This mediator approach transfers the vibration generation function from the piezoelectric element to the magnetic drive system, eliminating the resonance breakdown issue while maintaining high-frequency vibration capability
Solution Approach 2:
The piezoelectric mechanical vibration system is replaced with an electromagnetic vibration system. Instead of using piezoelectric materials that convert electrical energy to mechanical vibrations (prone to resonance), the patent uses electromagnetic induction to generate a magnetic field that drives a magnetic element to vibrate. This substitution replaces the problematic mechanical piezoelectric system with an electromagnetic system that avoids resonance breakdown
2Area of stationary object
If ultrasonic vibrations are applied to a large area, then treatment effectiveness increases, but the vibration energy dissipates before reaching deeper layers
Solution Approach 1:
The magnetic drive system generates periodic ultrasonic vibrations through alternating current in the vibration generation coil. The periodic magnetic field causes the magnetic drive element to oscillate at ultrasonic frequencies, creating sustained periodic vibrations that can penetrate deeper into the treatment area while maintaining energy concentration. This periodic action allows energy to be delivered in concentrated pulses rather than continuous diffuse vibration
Solution Approach 2:
The patent utilizes mechanical vibration at ultrasonic frequencies to achieve deep tissue penetration. The magnetic drive element vibrates mechanically at ultrasonic frequencies, and these vibrations are transmitted through the treatment medium. The high-frequency mechanical vibrations maintain energy concentration while covering a larger treatment area, solving the energy dissipation problem
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively increases the vibration strength of the device, preventing a decrease in vibration quality even with reduced size and thickness, ensuring efficient vibration propagation.
Implementation Method 1
a vibration generation coil that generates a magnetic field
Implementation Method 2
ultrasonic vibrations generated by a piezoelectric element
Data Source
Figure 1~2
Figure 3
Figure 4(a)~5
AI summary
To provide a vibration device in which a decrease in the strength of vibration involved in a reduction in thickness and size less easily occurs. A vibration device 1 includes a first elastic plate 2a including first and second end portions 2a4 and 2a5 and a first planar section 2a1 located between the first and second end portions 2a4 and 2a5, a second elastic plate 2b joined to the second end portion 2a5 side of the first elastic plate 2a, including a second planar section 2b1 opposed to the first planar section 2a1 of the first elastic plate 2a, and having flexural rigidity higher than flexural rigidity of the first elastic plate 2a, a piezoelectric vibrating element 3 provided on a surface on the second elastic plate 2b side in the first planar section 2a1 of the first elastic plate 2a, and a mass adding member 8 attached to the first end portion 2a4 of the first elastic plate 2a.