PVDF-driven flexible and transparent loudspeaker

Sugimoto, Takashige; Ono, Ken; Ando, Akio; Kurozumi, Kohichi; Hara, Akira; Morita, Yoshinori; Miura, Akira

doi:10.1016/j.apacoust.2009.03.007

Cited by 40 publications

(29 citation statements)

References 4 publications

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“…Since the invention of loudspeaker more than a century ago, many kinds of loudspeakers have been proposed and commercialized [41]. The next generation display devices require transparent and flexible loudspeakers for new audio environments.…”

Section: Transparent Loudspeakersmentioning

confidence: 99%

Application of Graphene-Based Transparent Conductors (TCs)

Zheng

Kim

2015

Graphene for Transparent Conductors

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As graphene has several potential advantages over indium tin oxide (ITO) including weight, robustness , flexibility, chemical stability, and cost, many applications, such as touch panels, displays, solar cells, organic light-emitting diode, transistors and other new areas, have been demonstrated [1]. Although the application of graphene for transparent conductors (TCs) is still in its early stage and the performances of some devices presented in this book are in a preoptimized state, the unique functional characteristics can make graphene a strong candidate to replace the currently commercially dominant TC materials [2]. These devices, with their functional, structural, and mechanical requirements, where graphene has been considered to apply are discussed in this chapter. Touch ScreenA touch screen is an electronic visual display that detects the presence and location of a touch [2]. A variety of touch-screen technologies, such as resistive, surface acoustic wave, capacitive, surface capacitance, projected capacitance, has been developed [3]. The most commonly used touch screens are the resistive and capacitive types, which require a sheet resistance of ~ 300-1500 Ω/sq at a transparency of ~ 86-90 % [4]. Graphene has several advantages including flexibility, wear resistance, chemical durability, and low toxicity (Fig. 5.1a-b) compared to the traditional ITO. Based on the successful fabrication of graphene films, with outstanding sheet resistance and transparency, and a large size of tens of centimeters, Bae et al.[5] incorporated them into touch-screen panel devices (Fig. 5.1b). It is revealed that the touch-screen display made from graphene outperformed that of ITO in terms of the applied strain. The former touch screen could handle twice as much strain as conventional ITO-based devices (Fig. 5.1c) [5]. The graphene-based panel resisted up to 6 % strain, which is limited mainly by the silver electrode and not by graphene itself, while the ITO-based touch panel easily broke at just 2-3 % strain.

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Section: Transparent Loudspeakersmentioning

confidence: 99%

Application of Graphene-Based Transparent Conductors (TCs)

Zheng

Kim

2015

Graphene for Transparent Conductors

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“…[12] Ohga proposed a bimorph structure consisting of a PVDF layer pasted on a polyester film substrate as a loudspeaker with multiresonances. [15] Later, layered structures of PVDF films pasted on fabrics [16] and a polyethersulfone film [17] were investigated for potential applications in active noise control and in flexible displays, respectively. Lee et al studied the acoustic performance of PVDF films with electrodes of different materials.…”

Section: Introductionmentioning

confidence: 99%

Fully Printed Piezoelectric Polymer Loudspeakers with Enhanced Acoustic Performance

et al. 2019

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Piezoelectric polymer loudspeakers have advantages like lightweight, flexibility, simple structure, and small volume, which make them favorable for a variety of applications. Herein, such loudspeakers are fabricated by screen printing the bottom and top electrodes (poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate), PEDOT:PSS) as well as the piezoelectric polymer layer (poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE)), in between on paper substrates. The dielectric properties of the printed loudspeakers are studied with dielectric spectroscopy. Thanks to the self-healing process during poling, the samples are successfully poled to saturation in spite of their large area of up to 300 cm 2 . The dependence of the acoustic output on remanent polarization and the active area of the piezoelectric layer is investigated. A sound pressure level (SPL) of about 91 dB at a distance of 1 m is obtained with array samples of five rectangular units (10 Â 6 cm 2 in area each). In particular, samples with two loudspeaker arrays printed, respectively, on both surfaces of the paper substrates are prepared, and a further increase of 6 dB in SPL is achieved when the two loudspeakers are driven in phase. The results not only deepen the understanding of fully printed piezoelectric polymer loudspeakers but also realize an SPL much higher than that reported in previous studies.

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“…In this study, we demonstrated, for the first time, the tri‐functional flexible device by using ZnS powder as phosphor layer and flexible piezoelectric polymer as dielectric layer. The device consists of silver nanowires as top electrode, and ZnS:Cu, Al phosphor screen‐printed on high piezoelectric polymer, i.e., polyvinylidene fluoride (PVDF) sheet, which is chosen due to its good dielectric and piezoelectric properties for speaker and its high flexibility and transparency . The fabricated device generated the light from the phosphor and the sound from PVDF sheet under a supply of external electric power, and additionally harvested the mechanical energy such as external strain or vibration to be converted into electric energy or light energy.…”

Section: Introductionmentioning

confidence: 99%

Multifunctional Flexible Device Based on Phosphor on Piezoelectric Polymer: Lighting, Speaking, and Pressure‐Light Converting

Lee

Kang

Lee

et al. 2018

Physica Status Solidi (a)

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In this paper, the tri-functional flexible device by using ZnS powder as phosphor layer and flexible piezoelectric polymer as dielectric layer is demonstrated. The fabricated device generates the electroluminescent (EL) light from the phosphor and the sound from the piezoelectric sheet under a supply of external electric power, and additionally harvests the mechanical energy harvesting to be converted into EL light. Under sinusoidal applied voltage, the EL luminances are exponentially increased, to our best knowledge, with the best-record luminous efficiency of 10 lm W À1 at 100 V and 400 Hz, and the sound pressure levels (SPLs) are linearly increased. The EL luminances are linearly dependent on the applied frequency while the SPLs show the parabolic increase behavior below 2000 Hz and then flat response. The temperature dependence on the EL luminances and the SPLs is demonstrated; the former is drastically increased and the latter is slightly decreased with the increase of temperature. Finally, as an energy harvesting application, the piezoelectric electroluminescence effect is demonstrated by applying the external pressure on the device without electric power. This trifunctional device is expected to be applicable to emergency warning system, advertising panel, and remote stress sensor in both power-on and -off circumstances.

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PVDF-driven flexible and transparent loudspeaker

Cited by 40 publications

References 4 publications

Application of Graphene-Based Transparent Conductors (TCs)

Application of Graphene-Based Transparent Conductors (TCs)

Fully Printed Piezoelectric Polymer Loudspeakers with Enhanced Acoustic Performance

Multifunctional Flexible Device Based on Phosphor on Piezoelectric Polymer: Lighting, Speaking, and Pressure‐Light Converting

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