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We have developed a thin film microsensor based on interdigital electrodes deposited on a glass substrate. If the film side of the sensor chip is pressed onto human skin, the change of capacitance can be used as a measure for the water content of the skin. As the front side of the sensor must remain flat, the interconnection wires have been fixed at the backside of the chip. In this paper we report on measurements with a frequency of 100 kHz to 2 MHz and a voltage of 100 mV. We compare measuring results on normal skin, atopic (dry) skin and skin moisturized by a humectant.

This pre-study investigates a fibre optic alternative to more conventional sensors for measuring force indirectly as bending or deflection in a medical robotic application. The paper discusses problems regarding the integration of fibre optics into a cutting tool for the removal of prostate gland tissue. The aim is to integrate the sensor in a tube rod with an inner diameter of 0.6 mm and use it as a force feedback sensor for the control system of the robot. The paper proposes and evaluates an inexpensive opto-mechatronic device for launching light into and detecting light received from an optical fibre. A simple sensor prototype is constructed to show the feasibility to use a fibre optic sensor for the prostate gland cutting tool.

This paper deals with the question of whether an inexpensive optical sensor head, a so-called CD pick-up, from a compact disc player system can be used for simultaneously directing light into and detecting light received from an optical fibre. The investigation shows that the CD pick-up is well suited for intensity-based fibre-optic sensors. The benefit of using a CD sensor head is that it is a small-sized module including a diode laser, driver, detector, signal conditioning and lens system. Furthermore, the study shows that the CD pick-up may be used for fibre-optic interferometry as well.

The water content in the superficial part of the human skin is one index to evaluate the skin health. In the past we have developed a packaging concept which brings a sensor chip carrying a comb-shaped electrode system into intimate contact with the skin. The electrical impedance between these electrodes can be used as a measure for the water content of the skin. However, we have recently found that the same sensor chip used with a slightly altered packaging concept can measure the transepidermal water loss (TEWL), which is another indicator for the skin health. In our paper we report on the interconnection and packaging technique of this advanced measuring system for the evaluation of human skin. Furthermore, we present some first measurement results. The basic structure of the sensor consists of a thin film interdigital electrode system deposited on a ceramic substrate by rf-sputtering. Thin wires are guided through funnel-shaped holes arranged in the center of the contact pads. A CO/sub 2/ laser with a wavelength in the medium infrared range is used to produce these holes. The wires are bonded to the contact metallizations by using conductive adhesives. In the case of TEWL measurements the sensor chip does not touch the skin. The chip is placed in a distance of a few millimeters away from the skin. The electrical impedance of the electrode system depends on the stream of water molecules emitted from the skin. This kind of measurement does not suffer from pollution of the sensor chip by the oily substances of the skin surface. Therefore, the results are more reproducible compared to classical skin impedance measurements.

We have demonstrated the pulse poling technique to activate the piezoelectric property of PZT thin films within 1 second. We have fabricated piezoelectric microcantilevers with Si proof mass using Pb(Zr0.52,Ti0.48)O3 (MPB-PZT) thin films. By applying 1 kHz and 100 V of unipolar triangle pulse voltage, the positive piezoelectric constant |d31| of PZT thin film has been enhanced as high as 95 pm/V, which is larger than dc poled PZT thin films (67 pm/V).

We developed an in‐situ measurement system for characterizing the relationship between ferroelectricity and lattice distortion of a ferroelectric thin film at BL13XU, SPring‐8. The dielectric polarization obtained and the lattice strain evaluated provide us with the electrostrictive coefficient of the film. The system for the method consists of a refractive lens for two dimensional micron focusing, ferroelectric characterization system, high‐precision four‐circle diffractometer, and time‐resolved photon counting system. It enables in‐situ measurements of the electric polarization of the film and an electric‐field‐induced strain using nano‐second order time‐resolved synchrotron diffraction. We applied the method to determining the lattice constant distorted by the electric field and the polarization value of a 410 nm‐thick BiFeO3 thin film. The piezoelectric constant d33 evaluated was about 28 pm/V. The polarization observed allowed us to evaluate an electrostrictive coefficient Q of 1⋅4×10−2 m4/C2.

Two methods for clinical optical light dosimetry are developed. In the first method, which is invasive, a fluorescent probe attached to an optical fiber is inserted by means of a thin hypodermic needle and measures light transmitted through the cheek as a function of the penetration depth. In the second noninvasive method, the diffusely reflected light intensity, from a small illuminated spot on the surface of the tissue to be investigated, is measured as a function of the radial distance along the surface. Preliminary results with both methods are presented. Simulations of the second measurements, which allow for a simplified extraction procedure of the relevant optical data from such measurements, are also shown.

The design of a robot for functional stereotactic surgery which is under construction in our laboratory is described. The main features include operation inside the computed tomographic (CT) scanner, the possibility of intraoperative CT scanning and complete handling of the stereotactic probes by the robot.

The strained surface layers of AT-cut quartz plates produced by lapping and polishing have been studied using the X-ray double crystal method. In addition, the influence of surface strain on the characteristics of quartz resonators has been investigated. Experimental results from X-ray double crystal measurements indicate that a residual stress layer in the lapped and polished surface is created and that the quartz resonator performance is also affected.