A taste sensor with global selectivity, i. e., electronic tongue, is composed of several kinds of lipid/polymer membranes for transforming information of taste substances into electric signal. The sensor output shows different patterns for chemical substances which have different taste qualities such as saltiness and sourness. Taste interactions such as suppression effect, which occurs between bitterness and sweetness, can be detected and quantified using the taste sensor. Amino acids can be classified into several groups according to their own tastes from sensor outputs. The taste of foodstuffs such as beer, coffee, mineral water and milk can be discussed quantitatively. The taste sensor provides the objective scale for the human sensory expression. We are now standing at the beginning of a new age of communication using digitized taste.

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In this paper, we present a fabrication technique that enables integration of polyimide into MEMS devices with multi-thickness layer structures. The technique is mainly to utilize a specific SOI (silicon on insulator) wafer with embedded pattern of silicon dioxide. An SOI wafer with a 10 micron thick device layer is thermally oxidized to 400 nm thick and patterned. The patterned side is bonded with another conventional silicon wafer. And then the handle layer of the SOI is removed by wet etching. Although the embedded pattern has 400 nm step structure, no pattern deformation takes place. By using this type of SOI wafers, we have developed a 2-dimensional optical scanner. The MEMS mirror has simultaneously achieved a high resonant frequency and a wide scan angle with no failure. Polyimide-based hinges and thin moving inertia, 10 micron thickness, lead to these characteristics.

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This paper reports a new photo-fabrication method of an actuator unit from a shape memory alloy (SMA) pipe. Three meandering actuators, which are linked one another, have been fabricated from an SMA pipe. The outer diameter and the wall thickness of the pipe are 600µm and 50µm, respectively. After the SMA pipe was dip coated with positive photoresist, the photoresist was patterned by using projection exposure method for an etching mask. The SMA pipe was electrochemically etched in the LiCl-ethanol solution with a Cu dummy layer, which was deposited on the inside wall of the pipe by electroless plating previously. The batch fabrication method can simplify the assembly of an active catheter, because the actuators are fabricated as a self-assembled unit.

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