Abstract: An earphone system is provided which enables a listener to listen to a localized stereophonic sound image by earphones while naturally listening to ambient sound. An earphone system (10) includes earphones (1) that are worn on ears and a signal output unit (13) that outputs a sound signal to the earphones (1). The earphone (1) includes a housing in a tubular shape whose internal space has openings at both ends or in a shape in which a portion of the tubular shape in a circumference direction is removed, a speaker unit that outputs a sound signal toward one of the openings, and a support portion that supports the speaker unit in a position which corresponds to the internal space of the tubular shape. Further, the signal output unit (11) includes a signal processing unit (13) that performs signal processing for an input sound signal to generate and output a sound signal of stereophonic sound in which a sound image is localized in a position that is assumed as an outside of a head.

Abstract: A projection type display device including a CRT with a fluorescent layer and a face glass for projecting an image reflected onto the fluorescent layer through the face glass, a transparent liquid, at least one lens element and onto a screen. The transparent liquid is filled within a space between the face glass of the CRT and the at least one lens element and has a refractive index substantially the same as a refractive index of the face glass of the CRT and the at least one lens element. A light attenuation filter having a transmittance no greater than 0.9 is disposed at a position from the fluorescent layer to the at least one lens element such as between the face glass and the at least one lens element.