• Title/Summary/Keyword: Micro Speaker Diaphragm

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A Study on the Acoustical Properties of Micro-speaker according to Comb Teeth Shape of the Diaphragm (진동판의 빗살주름무늬 형상에 따른 마이크로스피커의 음향특성에 관한 연구)

  • Lee, Tae-Keun;Kim, Byoung-Sam;Cho, Tae-Jea
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.6
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    • pp.124-131
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    • 2008
  • There are many factors which affect the acoustical properties of a micro-speaker. Among the factors, the shape of the diaphragm is considered in this study. As an investigating method, the finite element methods and measurement techniques applied to study the acoustical properties according to diaphragm shape. In order to vary the stiffness of the diaphragm, the some patterns of comb teeth, such as the angle and the number of comb teeth, are applied to diaphragm. We can confirm that the change of the stiffness by the changing diaphragm shape affects the vibration and sound properties of the speaker. As a result, the reduction of the angle of the comb teeth increases the diaphragm stiffness and shifts the resonance frequency to a higher frequency range. The number of the comb teeth is related to the stiffness of the edge part.

Relationship Between the Resonance Frequency and QTS for Microspeaker (마이크로스피커에서 공명진동수와 QTS 사이의 연관성)

  • Oh, Sei-Jin
    • Korean Journal of Materials Research
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    • v.21 no.7
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    • pp.403-409
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    • 2011
  • Micro speakers are used to reproduce sound in small electric and information and communications devices, such as cellular phones, PMPs, and MP3 players. The acoustical properties and sound quality, which are changed due to the decreased size of the speaker, are often adjusted varying the type and thickness of the diaphragm. The most widely used diaphragm material is thin polymer. It was previously reported by the author of this paper that the resonance frequency of a micro speaker is changed by the type and thickness of a polymer diaphragm. In this paper, the frequency response near the resonance frequency of a micro speaker was studied as functions of the type and thickness of the polymer diaphragm. While $R_{max}$ and $R_{DC}$ were affected by the type and thickness, an analysis of the electrical impedance curve revealed that $R_o(= R_{max}/R_{DC})$ and ${\Delta}f$ were not changed. Thus, $Q_{TS}$ which was function of $R_o$, ${\Delta}f$, and the resonance frequency, is only related to the resonance frequency. The increase of the resonance frequency led to a proportional rise of $Q_{TS}$. The change of the frequency response near the resonance frequency was not dependent on the type or thickness of the polymer diaphragm, but was affected by the resonance frequency.

Studying Acoustical Properties of Micro-Speaker as a Function of Diaphragm Material (진동판의 재질에 따른 마이크로스피커의 음향특성연구)

  • Oh Sei-Jin
    • The Journal of the Acoustical Society of Korea
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    • v.25 no.5
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    • pp.222-228
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    • 2006
  • The acoustical property of micro-speaker had been investigated as a function of the diaphragm material in this study. Young's modulus and the density of material is deeply related to the determination of sound velocity and stiffness. As a result, it was appeared that the resonance frequency of micro-speaker was PEI < PPS < PET < PEN. This experimental result was in an excellent agreement with the theoretical one. The increasing ratio of sound pressure level to the frequency between 20Hz and the resonance frequency ($f_s$) and the high resonance frequency ($f_h$) were not affected by the diaphragm material.

Relationship Between Geometrical Stiffness of Diaphragm and Resonance Frequency for Micro-speaker (마이크로스피커 진동판의 등가탄성과 공명진동수의 연관성)

  • Oh, Sei-Jin
    • Korean Journal of Materials Research
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    • v.20 no.12
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    • pp.640-644
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    • 2010
  • Information technology devices, such as cellular phones, MP3s and so on, due to restrictions of space, require thin and small micro-speakers to generate sound. The reduction of the size of micro-speakers has resulted in the decrease of sound quality, due to such factors as frequency range and sound pressure level. In this study, the acoustical properties of oval microspeakers has been studied as a function of pattern shape on the diaphragm. The other conditions of micro-speakers, except for the pattern, was not changed. When the pattern is present on the diaphragm and the shape of pattern was a whirlwind, the resonance frequency was reduced due to the decrease of tensile strength of diaphragm. The patterns presented in the semi-minor axis of diaphragm did not effect a change of resonance frequency. However, increasing the number of patterns in the semimajor axis of diaphragm became a reason for the decrease of resonance frequency on edge side. When the depth of pattern on edge side was increased, the resonance frequency was decreased due to reduction of geometrical stiffness. If the height of edge and dome were increased, the resonance frequency and geometrical stiffness rapidly increased. After reaching the maximum values, they began to decrease with the continuous increase of height.

Vibration Analysis of Micro Speaker Diaphragm (마이크로 스피커 다이어프램의 진동해석)

  • Hong, D.K.;Woo, B.C.;Ahn, C.W.;Han, G.J.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.551-554
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    • 2005
  • This study uses a characteristic function to explain correlations between the objective function and design variables. Analysis of means and table of orthogonal array were carried out. The change of shape of diaphragm, thickness of diaphragm and voice coil weight based on the table of orthogonal array is made. Therefore this study carried to decide shape of diaphragm, voice coil weight and thickness of diaphragm for minimizing 1st natural frequency and maximizing 2nd natural frequency of diaphragm using design of experiments and characteristic function with constraints. we showed improved design factors that minimized 1st natural frequency and maximized 2nd natural frequency of diaphragm.

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Investigation on Vibration Characteristics of Micro Speaker Diaphragms for Various Shape Designs (마이크로 스피커 진동판의 형상설계에 따른 진동특성 고찰)

  • Kim, Kyeong Min;Kim, Seong Keol;Park, Keun
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.8
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    • pp.790-796
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    • 2013
  • Micro-speaker diaphragms play an important role in generating a desired audio response. The diaphragm is generally a circular membrane, and the cross section is a double dome, with an inner dome and an outer dome. To improve the sound quality of the speaker, a number of corrugations may be included in the outer dome region. In this study, the role of these corrugations is investigated using two kinds of finite element method (FEM) calculations. Structural FEM modeling was carried out to investigate the change in stiffness of the diaphragm when the corrugations were included. Modal FEM modeling was then carried out to compare the natural frequencies and the resulting vibrational modes of the plain and corrugated diaphragms. The effects of the corrugations on the vibration characteristics of the diaphragm are discussed.

A Study on the Shape Design of Micro Speaker Diaphragm (마이크로 스피커 다이아프램의 형상설계에 관한 연구)

  • Hong, Do-Kwa;Woo, Byung-Chul;Kim, Dong-Young;Ahn, Chan-Woo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.7 s.100
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    • pp.775-780
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    • 2005
  • This study uses a characteristic function to explain correlations between the objective function and design variables. Analysis of means and table of orthogonal array were carried out. The change of shape of diaphragm, thickness of diaphragm and voice coil weight based on the table of orthogonal array Is made. Therefore this study carried to decide design variables for minimizing 1st natural frequency and maximizing 2nd natural frequency of diaphragm using design of experiments and characteristic function with constraints. we showed improved design variables.

Relationship Analysis of Break-up Mode and Heat Transfer of Micro-Speaker Diaphragm (마이크로 스피커 진동판에 대한 분할진동 모드와 열전달의 관계 분석)

  • Kim, Hyun-Kab;Kim, Hie-Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.4
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    • pp.333-336
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    • 2017
  • A speaker diaphragm generates a divided vibration. The influence of the break-up mode is sufficient to cause a shape change in the diaphragm. In this paper, is widely used in ultra-thin multi-media devices, including smart phones is the advance guard of the IT sector, the micro-speakers and its target. Micro-speakers are different from general speakers. The plate has structural form and space constraints. In particular, they utilize a closed-type drive space. It is difficult to provide cooling for the auxiliary suspension structure because of the heat generated in the moving coil. The present study considered the relationship between the break-up mode and the heat transfer of the diaphragm. An experiment was conducted in two stages to compare the embodiment of the break-up mode and heat transfer in a certain frequency range. The changes in the heat were determined through measurements and thermal imaging of the break-up mode. The break-up mode tendency of the diaphragm could be rapidly predicted based on the imaging results using the thermal imaging camera. This will help in the optimal design of micro-speakers.