Sensor in Japan

Table I. Production Record of Humidity Sensors in Japan...

Figure 4. Production record of oxygen sensors in Japan.

FET type humidity sensor. Although sensors based on a field-effect transistor (FET) appear to hold promise as a small and low-cost intelligent sensor, relatively few people have been engaged in the research on FET type sensors in Japan. In this respect, it is remarkable that a FET type humidity sensor was developed recently by Hijikigawa of Sharp Corp (9). The sensor is also worth notice as a new type of humidity sensor, which utilizes changes in electric capacitance of humidity sensitive membrane interposed between double gate electrodes. 

Matsuura S 1993 New developments and applications of gas sensors in Japan Sensors Actuators B 13-14 7-11... 

In the near future, UV photodiodes made from polycrystalline wide band-gap semiconductors may fill the gap in the market. Although they have a lower sensitivity (photocurrent per area) they promise to have a better merit-rating in terms of photocurrent per sensor costs. The other major drawback of polycrystalline photodiodes, the risetime of micro- to milliseconds, is not relevant for household applications. Fuji Xerox Laboratories in Japan are developing visible-blind UV photodiodes made from polycrystalline GaN [12], while twlux AG in Berlin, Germany is developing visible-blind UV photodiodes made from polycrystalline titanium dioxide [13]. A prototype is shown in Fig. 5.45. 

Domestic wastewater contains a large amount of detergents, especially anionic surfactants, such as linear alkylbenzene sulfonates (LAS). A sensitive biosensor containing Trichosporon cutaneum has been developed in Japan and used to monitor river water [128,129]. With this sensor a detection limit of 0.2 mg 1" LAS has been reached. 

Several CDs applications have been discussed in Chapter 6. Their lack of toxicity forms the basis for their applications in pharmaceutical, agrochemical, and food industries as well as in toiletry and cosmetics [lb, lc]. They are also used or have been proposed to be applied, as sensitizers and stabilizers of dyes in photography, for impregnating paper, as fluorescent and other sensors [28], as corrosion inhibitors and rust proofing materials, UV stabilizers and antioxidants. One of the most spectacular is the prospective use of CDs as biodegradable plastics [29]. The complex of nitroglycerine with p-CDmarketed in Japan was mentioned in Chapter 1 while some other CDs applications have been presented in Chapter 6. 

The production of gas sensors. The production records of various types of gas sensors for past five years in Japan are listed in Table I except for the oxygen and humidity sensors. The sensors produced in the largest quantity are of the semiconductive type, followed by the catalytic combustion and thermistor types. These sensors have been mostly applied to domestic uses such as gas leakage alarms or gas control systems for LP gas and town gas which are extensively used for cooking and heating in Japanese houses. This is why these sensors are manufactured on a large scale. Other electrochemical sensors have been developed mainly to monitor other gases. 

Humidity sensor. There exists a strong demand for humidity sensors especially in Japan because of humid weather in summer. The use of humidity sensors has been widely spreading in industrial fields as well as domestic. The production record is listed in Table I. 

Many problems and tasks, both scientific and technological, still remain in the field of gas sensors. For example, microsensors, intelligent sensors, cord-less sensors, etc., seem to be very important as well as attractive.- However, these are not covered here, and only trends in sensor application anticipated in the near future in Japan are pointed out below. 

Wakabayashi, K. Ohta, S. Takemori, D. shirae, E. "Non-Linear Behavior of Glass Substrate in High Humidity", in "Chemical Sensors", Seiyama, T. Feuki, E. Shiokawa, J. Suzuki, S., Editors, Proceedings of the International Meeting on Chemical Sensors, Fukuoka, Japan, Analytical Chemistry Symposia Series -Volume 17, Elsevier, New York, pp. 439-444. 

Shichiri et al(ll) (Osaka University in Japan) has developed the micro needle type glucose sensor, which consisted of a hydrogen peroxide electrode and a GOX enzyme immobilized layer. The sensor was clinically used, but it had to be renewed after a few days because of a gradual decline in its output. 

Metal oxide semiconductor (MOS) sensors were first used commercially in the 1960s as household gas alarms in Japan under names of... 

Eiichi Kimura is retired from the Department of Medicinal Chemistry at Hiroshima University in Japan. His recent research interests have included the supramolecular chemistry of macrocyclic polyamines and their use in molecular recognition and as zinc-enzyme models. These interests have led to the development of fluorophore sensors for Zn(II) [8] use of macrocycles to effect selective recognition of anions [9], nucleobases in polynucleotides [10], thymidine mono- and diphosphate nucleotides (11), carbonic anhydrase and carboxypeptidase [12], and development of Zn(II)-macrocycle anti-HIV agents [13], In May 2004, he received a Purple Ribbon Award from the Emperor of Japan. 

Table III is a summary presentation of the CCD image sensor products of various companies in Japan, while Figure 8 shows the change in numbers of elements for photo-electric transducers. In the background of this change there was a great improvement in the clarity of pictures in home video systems (the photo-sensor for surface recognition of course was not developed exclusively for these measurements but was adapted from the general type).

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