We describe a fully programmable Electrostatic Tactile (ET) feedback system that delivers a range of tactile textures to a mobile display. The ET system is a robust, thin, and optically transparent structure that can be overlaid unobtrusively on top of a display screen. The system exploits the phenomenon of electrovibration to create a controllable frictional force between a user's fingertip and the surface. The system enables the realization of localized tactile information delivered to the user's skin directly, without moving parts. A tactile image is formed in accordance with the visual information displayed (virtual textures, tactile silhouettes, etc.). The magnitude and pattern of the frictional force on the display can be programmed to correspond to the images shown on the display and actual coordinates of the touch interaction in real time. This has been achieved using a variety of different materials, including those that are compatible with flexible devices.

In this paper, the Murata ceramic Bluetooth antenna, which has been successfully used on rigid printed circuit boards, is now applied to flexible printed circuit boards. Based on this Bluetooth antenna, a novel wrist device that can be wirelessly connected to mobile phones is developed. In particular, to reduce the height of the wrist device, the ground-clearance type Murata Bluetooth antenna is adopted. It is demonstrated that the wrist device works very well in real environments.

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This paper presents a design optimization of a membrane-based ultrasonic piezoelectric transducer using micromachining by finite element simulation. The transducer can be used to generate ultrasound using the piezoelectric film to excite the vibration of the transducer membrane. The objective is to maximize the vibration magnitude of the membrane by optimizing the structure of the transducer, when the exciting signal is fixed. The size and the shape of the piezoelectric film were selected as the design parameters to optimize the structure of the transducer. Based on the theoretical analysis, it is found that the absolute values of the stresses in the center and the boundary of the diaphragm are greater than that on the other regions of the film, with the directions of the stress on center and boundary opposite to each other. In order to achieve the maximum exciting efficiency, the discrepancy in the stresses between the center and the boundary on the diaphragm should be maximized. In this paper, totally four different piezoelectric film structures are analyzed for optimizing the exciting efficiency of the transducer. The finite element models of the transducer were created using ANSYS. The simulations based on the three design options were performed; and through the comparison of the simulation results, the optimal structural parameters of the piezoelectric film are identified. Finally, the direction of the design improvement for the exciting efficiency of the transducer is provided.

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