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Study of the effect of distance and misalignment between magnetically coupled coils for wireless power transfer in intraocular pressure measurement.

Rendon-Nava AE, Díaz-Méndez JA, Nino-de-Rivera L, Calleja-Arriaga W, Gil-Carrasco F, Díaz-Alonso D - ScientificWorldJournal (2014)

Bottom Line: Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity.The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal.In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them.

View Article: PubMed Central - PubMed

Affiliation: Graduate Department, National Polytechnic Institute of Mexico (IPN), ESIME UPC, Avenida Santa Ana 1000, San Francisco Culhuacan, 04260 Mexico City, DF, Mexico.

ABSTRACT
An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them.

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Related in: MedlinePlus

MEMS capacitive sensor prototypes, fabricated at the National Institute of Astrophysics, Optics and Electronics.
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Related In: Results  -  Collection


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fig3: MEMS capacitive sensor prototypes, fabricated at the National Institute of Astrophysics, Optics and Electronics.

Mentions: Several MEMS capacitors prototypes have already been fabricated at the facilities of the National Institute of Astrophysics, Optics and Electronics in Puebla, Mexico, as shown in Figure 3 [20]. A Touch mode capacitive pressure structures were fabricated by using a three-layer Polysilicon surface micromachining process called PolyMEMS-INAOE [21]. The main advantage of the fabrication process is its capability of building a suspended diaphragm over a cavity by removing sacrificial material due to a novel design. The design of MEMS IOP sensor includes a set of holes along two opposite diaphragm sides to allow the flow of the etch solution, whereas the other sides are fully clamped. At the same time it is possible to keep the cavity closed, with a subsequent sealing step, without the necessity of bonding techniques to form the final device. The variation range in capacitance of the sensor is of approximately 2 pF. Considering the dimensions of the sensor (600 μm in diameter/side) such as active area, distance between plates, and the thickness of the bending plate, the variation range in capacitance of the MEMS sensor corresponds to a variation in pressure of 10 mm Hg to 80 mm Hg.


Study of the effect of distance and misalignment between magnetically coupled coils for wireless power transfer in intraocular pressure measurement.

Rendon-Nava AE, Díaz-Méndez JA, Nino-de-Rivera L, Calleja-Arriaga W, Gil-Carrasco F, Díaz-Alonso D - ScientificWorldJournal (2014)

MEMS capacitive sensor prototypes, fabricated at the National Institute of Astrophysics, Optics and Electronics.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4109074&req=5

fig3: MEMS capacitive sensor prototypes, fabricated at the National Institute of Astrophysics, Optics and Electronics.
Mentions: Several MEMS capacitors prototypes have already been fabricated at the facilities of the National Institute of Astrophysics, Optics and Electronics in Puebla, Mexico, as shown in Figure 3 [20]. A Touch mode capacitive pressure structures were fabricated by using a three-layer Polysilicon surface micromachining process called PolyMEMS-INAOE [21]. The main advantage of the fabrication process is its capability of building a suspended diaphragm over a cavity by removing sacrificial material due to a novel design. The design of MEMS IOP sensor includes a set of holes along two opposite diaphragm sides to allow the flow of the etch solution, whereas the other sides are fully clamped. At the same time it is possible to keep the cavity closed, with a subsequent sealing step, without the necessity of bonding techniques to form the final device. The variation range in capacitance of the sensor is of approximately 2 pF. Considering the dimensions of the sensor (600 μm in diameter/side) such as active area, distance between plates, and the thickness of the bending plate, the variation range in capacitance of the MEMS sensor corresponds to a variation in pressure of 10 mm Hg to 80 mm Hg.

Bottom Line: Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity.The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal.In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them.

View Article: PubMed Central - PubMed

Affiliation: Graduate Department, National Polytechnic Institute of Mexico (IPN), ESIME UPC, Avenida Santa Ana 1000, San Francisco Culhuacan, 04260 Mexico City, DF, Mexico.

ABSTRACT
An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them.

Show MeSH
Related in: MedlinePlus