38 research outputs found
Thick-Film Actuation Technologies For MEMS Applications
No full textThis paper compares two thick-film actuation technologies and assesses their suitability for use within micromachined devices. The materials are a piezoelectric composition, which exhibits a d33 coefficient of the order of 130pC/N, and a magnetostrictive material which possess a magnetostriction of 4.4ppm at a magnetic field of 11.5kA/m. Examples of their application in micromachined devices are also given
Improving the piezoelectric properties of thick-film PZT: the influence of paste composition, powder milling process and electrode material
No full textThis paper details improvements of the d33 coefficient for thick-film Lead–Zirconate–Titanate (PZT) layers. In particular, the effect that the powder milling process has on particle size, shape and distribution has been investigated. Ball milled, jet milled and attritor milled powders were obtained from Morgan Electro-Ceramics Ltd. These powders were mixed with various ratios of lead borosilicate glass in the range of 5–20% by weight and an appropriate quantity of Electro-Science Laboratories (ESL) 400 solvent to formulate a screen printable thixotropic paste. The use of a polymer top electrode to reduce the number of firing cycles the PZT layer is subjected to was also investigated. The results show that the highest values of d33 were obtained from the ball milled powder with 10% glass content, but the most consistent results were obtained from the attritor milled samples. The samples printed with a polymer top electrode have shown an average increase of around 15% in the value of d33
Optimisation of the piezoelectric properties of thick-film piezoceramic devices
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Dataset for dispenser printed sound emitting fabrics for applications in the creative fashion and smart architecture industry
No full textThis paper reports direct write dispenser printed sound emitting smart fabrics aimed at creative fashion applications and smart architecture. Planar spiral speakers generate a membrane vibration and so emit sound when driven from an a.c. audio source if a magnet is in close proximity to the spiral. The speaker designs were printed on polyester cotton fabric and produced a measured peak sound output level of 85 dB referenced to a reference sound pressure in air of 2×10-5 Pa. The printed fabric speakers demonstrate a wide frequency response from 20 Hz to 20 kHz. This research demonstrates a straightforward fabrication method to achieve sound emission from a fabric. The fabrication process requires a processing temperature of 130 oC for 10 minutes which is compatible with many fabrics. It also offers complete freedom of the creative design. This fabrication method is a direct write technique offering no waste and achieves a conductor resistivity of 7.69×10-6 ?·m . This paper reports on the theory and the manufacturing technology to achieve direct write dispenser printed planar spiral speakers on fabrics. </span
Data for the figures in Smart Textile Based Flexible Coils for Wireless Inductive Power Transmission
No full textThis data set includes the data used for following plots in paper Smart Textile Based Flexible Coils for Wireless Inductive Power Transmission.
Fig. 3. Unloaded Q factor versus the turns of spiral coil for a coil design that has 138 mm external diameter, 53 mm inner diameter, and is printed with a conductive paste which has 24 m?/? sheet resistance.
Fig. 6. Normalized DC resistance versus curing time for conductive tracks with different number of sub-layers printed on interface-coated textile. The conductive paste is cured after 40 minutes 130 °C thermal curing.
Fig. 7. Thickness and practical DC resistance of printed conductive layer as designed coil compared with theoretical DC resistance in different number of sub-layers and thickness.
Fig. 9. Impedance phase angle of different type of coils on frequency range from 300 kHz to 50 MHz. The self-resonant frequency can be located from this measurement as 10.3 MHz and 17.6 MHz for wound copper coil and flexible coils, respectively.
Fig. 10. Coupling factor k of different type of coupled coils against distance between them compared with the theoretical calculations.
Fig. 11. Output powers of wireless power transfer system deployed with different type of coupled coils against output DC current at 5 mm and 10 mm separation between transmitter and receiver coils. An approximate 1.51 W output power can be achieved for all types of coils at 5 mm separation, and 9 % less output power, 1.37 W, can be achieved at 10 mm separation.
Fig. 12. DC to DC efficiency at optimal output current against separation distance between different types of paired coils. The same trends of the effect of separation on DC to DC efficiency are shown on all types of coils.
Fig. 13. Maximum output power and DC to DC efficiency of WPT employed flexible coils with varying curvature of receiver coil at 5 mm center separation distance from transmitter coil. The maximum output power drops 33 % as a result of the deformation of the receiver coil.
Fig. 14. DC to DC efficiency of the WPT system employing a deformed receiver coil under different curvature against the separation distance from the flat transmitter coil.
Assigned DOI: 10.5258/SOTON/376588</span
A study of the effect of powder preparation and milling process on the piezoelectric properties of thick-film PZT
No full textThis paper details a study of the influence of Lead Zirconate Titanate (PZT) powder preparation and milling process on the d33 coefficient of thick-film PZT layers. In particular, the influence of the powder milling process and its effect on particle size, shape and distribution has been investigated. Ball milled, jet milled and attritor milled powders were obtained from Morgan Electro Ceramics Ltd. These powders were mixed with various ratios of lead borosilicate glass in the range 5 to 20% by weight and an appropriate quantity of ESL 500 solvent to formulate a screen printable paste. The results show the highest values of d33 were obtained from the ball milled powder with 10% glass content, but the most consistent results were obtained from the attritor milled samples
Dispenser-printed sound-emitting fabrics for applications in the creative fashion and smart architecture industry
No full textThis paper presents a printing technology for the design and manufacture of interactive planar speakers. With this technology, sound emission can be easily integrated into various textiles at the design stage with minimal assembly after printing. This paper reports direct-write dispenser-printed sound-emitting smart fabrics, aimed at creative fashion and smart architecture applications opening up new opportunities in product design. Planar spiral speakers generate a membrane vibration and so emit sound when driven from an a.c. audio source if a magnet is in close proximity to the spiral. These speakers can be integrated on fabrics to form the basis of clothing in fashion applications. The speaker designs were printed on woven polyester fabric and produced a measured peak sound output level of 85 dB with a wide frequency response from 20 Hz to 20 kHz. This research demonstrates a straightforward fabrication method, based on dispenser printing, to achieve sound emission from a fabric. The fabrication process requires a processing temperature of 130 °C for 10 min which is compatible with the majority of fabrics which are used in fashion and architecture industries. This paper reports on the theory and the manufacturing technology to achieve direct-write dispenser-printed planar spiral speakers on fabrics.</p
Textile-based flexible coils for wireless inductive power transmission
No full textWireless inductive power transmission systems can potentially supply wearable devices. Power cables or batteries can be eliminated by implementing a wireless power transfer system, making the wearable devices less obtrusive to users. However, rigid coils can cause discomfort to users in wearable applications. The novel screen-printed flexible coils on textiles reported here are intended to be a low-cost and comfortable solution when integrated into clothing. A constant-width circular-spiral flat coil has been designed to minimize the detrimental effect of the low conductivity of the screen-printed flexible conductors on the efficiency of the wireless power transfer system. The coils are printed on 65/35 polyester/cotton textile with a screen-printed Fabink-UV-IF1 interface layer coating. The interface layer provides a relatively flat and smooth surface to prevent the permeation of the conductive paste into the textile and allows the printing of finer-profile coils. A 5 V 1.2 W DC output has been achieved by a wireless power transfer system using the printed flexible coils with Qi standard circuitry; a DC-DC efficiency of 37% has been measured
Energy harvesting power supplies for electronic textiles
No full textElectronic textiles (e-textiles or smart fabrics) are textiles that include smart, electronic functionality. Examples include integrated LEDs embedded within yarns [1] , printed functional materials deposited on the surface of the textile [2] and complex flexible circuits woven into the fabric [3]. The supply of power is a key challenge for wearable technologies generally and e-textiles in particular since existing solutions are typically battery powered and the rigid nature of conventional batteries is incompatible with the feel and nature textiles. Alternative power supplies using energy harvesting and wireless power transfer techniques could provide an alternative solution to supply power. Energy harvesting systems also typically require an energy reservoir to provide an energy buffer to accommodate the variations in power supplied from the harvesting solution. Combining flexible energy harvesting techniques with a textile-based energy storage reservoir offers the potential for autonomous textile power supplies suitable for use in future integrated e-textile applications.</p
