Study On Piezoelectric Bone Conduction Hearing Equipment With Circular Structure

Based on the work of predecessors, this paper presents a piezoelectric bone conduction hearing Equipment programmer applying hearing physiology principle and reversed piezoelectric effect of piezoelectric components. Relevant basic theory, structural design, test and other aspects of the research work have been carried out. The main contents are as follows:1. Research,development and application of Bone conduction hearing equipmentBone conduction hearing equipment is generally composed of microphone ,amplifier and electromechanical transducer (vibrator), etc. According to differ-ent principles of vibrator,bone conduction hearing equipment can be divided into electromagnetic bone conduction hearing equipment and piezoelectric bone conduction hearing equipment. Because of defaults of electromagnetic bone conduction hearing equipment, its application has been constrained in many respects.But piezoelectric bone conduction hearing equipment has manyadvantages that electromagnetic bone conduction hearing equipment does not have such as loss with no electricity, no electromagnetic radiation, light wei-ght, thin profile, it has broad applicability and gets people's much favor. It also gets more and more researchers'concern because of its tremendous dev-elopment prospects.2. Theoretical foundation of piezoelectric bone conduction hearing equipmentBecause piezoelectric bone conduction hearing equipment integrates principles of hearing physiology and reversed piezoelectric effect of piezoelectric material. Hearing physiology and piezoelectric knowledge are the basis of designing piezoelectric bone conduction hearing equipment with good properties. Some basic knowledge of hearing physiology is introduced in this paper such as physical nature of sound, two pathway of voice (bone conduction and gas conduction) and hearing threshold, etc. This paper also introduces some piezoelectric basic knowledge including piezoelectric effect, relevant performance parameters and vibration mode of the piezoelectric oscillator, the material of the circular piezoelectric oscillator and the way of manufacture..3. Research of supporting way for audible components in piezoelectric bone conduction hearing equipmentPiezoelectric oscillator is the acoustic occurrence component of the piezoelectric bone conduction hearing equipment. The supporting way is an important factor to the performance of piezoelectric bone conduction hearing equipment. With three supporting ways of surrounding fixation, middle fixation and simple fixation, finite element model for the piezoelectric oscillator are established in this paper. Its displacement characteristic and vibration mode are analyzed to identify the vibration mode in day to day sounding frequencies. Through the test of deformation and loudness characteristics in three supporting ways of surrounding fixation, middle fixation and simple fixation, deformation of the piezoelectric oscillator and corresponding loudness of the voice are studied. Analysis tells that, the performance of piezoelectric oscillator with the supporting way of surrounding fixation is superior to other supporting way in all aspects. So surrounding fixation is chosen to be the supporting way of the piezoelectric oscillator in the piezoelectric bone conduction hearing equipment.4. Structure design and experimental study on the piezoelectric bone conduction hearing equipmentAfter the structure design of the piezoelectric body bone conduction hearing equipment, some experiments about some structural parameters'effect to its performance are carried on and experiments data shows that the structure design meet the technology requirements. Through experiments about structural parameters such as diameter, thickness, gripping distance piezoelectric oscillator, etc. affecting performance of the piezoelectric body bone conduction hearing equipment, it shows that, structural parameters which affect displacement of the piezoelectric oscillator also affect the vibrator loudness of the piezoelectric oscillator. It provides a basis for improving performance of the piezoelectric bone conduction hearing equipment. Amplification circuit of the piezoelectric bone conduction hearing equipment is also been designed, simulated and experimented. And these simulation and experiments show that the piezoelectric bone conduction hearing equipment with the amplification circuit has a good performance.