In this paper, we propose a large-area tactile display by controlling suction pressure. This research is based on our discovery of tactile illusion that pulling a skin through a hole with air suction causes a sensation as if something like a stick is pushing the skin. This illusion implies that our mechanoreceptors are insensitive to the sign of stress (negative or positive), i.e. we detect not stress directly but strain energy. There are two key concepts to realize our tactile display. One is the tactile illusion mentioned above and the other is "multi primitive tactile stimulation." We explain our approach to produce various tactile sensations from a sharp edge to a plane surface with a simple structure of display device based on air pressure control, and report the experimental results.

The forms of communication available now are categorized into the one or three dimensional. One dimensional communication includes metal wires and optical fibers in which the electro-magnetic field is confined in one dimensional medium. Wireless communication based on RF or optical connection emits electro-magnetic field in 3-D space. Now what if we have "two-dimensional communication" in which signals travels from one point to another point freely in elastic two-dimensional space using electromagnetic field confined in 2-D space? In this paper, we describe such a new technology of 2-D communication brings new paradigm to robotics. The methodologies of machine-design, system-integration, sensing, and computing will be drastically changed. We show architecture of the 2-D signal transmission based on relaying packets between communication chips on a thin sheet, the physical structure of the 2-D signal transmission, the protocols of the signal relay, and the results of the basic experiments.

In this paper, we show a hypothesis on the sensing mechanism in the human tactile organ and its resolution. The hypothesis is that human skin cannot resolve any finer pattern than the resolution suggested by the two-point-discrimination test, but that variety created by four kinds of signals from four kinds of mechano-receptors makes it possible to detect fine feature of texture. This means if we control stimulus to four kinds of mechanoreceptors individually, the realistic contact-feeling display will not need higher spatial resolution than suggested by the two-point discrimination threshold. We examine this hypothesis through psychophysical experiments.

In this paper, we propose a device to stimulate only the superficial mechanoreceptors in the skin, and report the feeling caused by the stimulus. We describe the principle of the selective stimulation using air pressure, and we show the selectivity is more advanced than that of our previous system using magnet chips which was presented last year. We experimentally confirmed that a sparse array of the superficial stimulators could display realistic touch on objects including finer virtual textures than the stimulator spacing.