Conventionally, the controlled release of aroma molecules has been achieved by employing mechanical devices; however, it has not been possible to avoid the noise and gusts of air that devices emit prior to transmitting aroma information. Another problem is the adherence of odor components to the device structure, because the aroma source is located inside or at the bottom of the device. In this chapter, the authors focus on a chemical container of a functional polymer gel (temperature-responsive hydrogel) that features a reversible phase transition between sol and gel and the controlled release of aroma molecules using a Peltier module to control temperature. By this approach, they developed a soundless olfactory display based on an aroma chip and solved the problem of the adhesion of odor components by placing a card-based aroma source (aroma-chip array) on the top of the olfactory display.
TopIntroduction
Human beings acquire information from the external world through five senses (sight, sound, smell, taste, and touch), but traditional media such as Television (TV) and Personal Computers (PC) provide only Audiovisual (AV) information. As a consequence, users do not have access to other information modalities. The use of olfactory information, for example, may effectively promote a more realistic experience and sense of presence by transmitting aromas associated with a particular location (Washburn, 2004). With this in mind, a variety of olfactory displays have been proposed (Kaye, 2001; Yamanaka, 2002; Yanagida, 2004; Yamada, 2006; Kim, 2006).
Previous systems, however, have employed mechanical devices to control the release of aroma molecules, which implies that the noise and gusts of air associated with the operation of such devices cannot be avoided prior to each transmission of olfactory information. For example, solenoid valves and switching devices, which are used to generate aroma molecules, make noise with the result such that users could perceive auditory information prior to olfactory information. In addition, blowers, fans, air pumps, and air compressors generate air gusts (perceptible airflow) by the use of air streams to convey aroma molecules. Hence, users can also feel a breeze before the aroma reaches them.
In short, by employing mechanical devices, while olfactory information is usually received without auditory and tactile information, noise and gusts of air would precede the aroma. Moreover, because the aroma source in such systems is usually located inside or at the bottom of the device, odor components would adhere to the structure preventing the release of different aromas using the same device.
To solve these problems, we have been focusing our research on the next generation of biomedical Drug-Delivery System (DDS). A DDS is used to ensure that drugs enter the body and reach the target area. A functional polymer gel is widely used as a drug carrier material in the DDS field (Ulijn, 2007; You, 2010). This gel acts as a kind of a chemical container or chemical valve (Beebe, 2000; Yoshida, 2010), which might be promising for the controlled release of aroma molecules without the noise and gusts of air associated with mechanical devices.
In this study, we seek to develop an effective and soundless olfactory display for generating natural olfactory information. We also attempt to solve the problem of the adhesion of odor components by placing the aroma source (aroma-chip array in an aroma card) on the top of the olfactory display.