The readability on the 7 segments numerical light emitting display devices installed cars were examined under several visual conditions to investigate the visibility. The three samples were classified with respect to the type. The experimental conditions were established so that visual angle was 1.0° and illuminance was scoped 0lx to 10000lx. Five experimental subjects read random indicative numerals with 0 to 9 in the dark room, which were presented for 0.1 second. The following results were obtained from the readability tests.
(1) The light emitting display devices and the negative type liquid crystal display device showed significant differences with respect to the illuminances and the indicative numerals, since the differences of the classified samples and the numeral's form.
(2) According to increase of the illuminance, the readabilities of three samples have gone down. The vacuum fluorescent display tube have been more influenced by the glares due to reflection of covered glass than light emitting display device. Then the readability of negative type liquid crystal display device has reduced since a perception of the just before readable numeral.

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Roles of active touch are investigated experimentally in roughness discrimination test. In the first experiment, the subjects made a roughness discrimination between a pair of emery papers by active finger movement. Velocities, applied forces, and direction of finger movement were measured. It was found that these measurements were identical between a pair of stimuli. Secondly roughness discrimination was carried out with different velocities, different forces, and different directions. Then the performances of discrimination deteriorated, irrespective of active and passive touch. These results indicate that roughness perception depends mainly on the cutaneous information, and the role of active touch in roughness discrimination is to make finger movements identical.

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