Abstract: The object of the present invention is to provide a multi-person shared display device with which a display device can be shared by a plurality of persons. For this purpose, a display device of the present invention is configured by a large screen display 112 and a display mask 114, which covers and hides a portion thereof. The display mask 114 is disposed at a position only an appropriate distance away from a display surface 116. The display mask 114 has a hole 118, and only through that portion can the display surface 116 of display 112 be seen. By introducing such display mask 114, the region visible upon the display surface differs depending on the viewpoint position of the user. As a result, it becomes possible to provide different content for every user.

Abstract: The object of the present invention is to provide a multi-person shared display device with which a display device can be shared by a plurality of persons. For this purpose, a display device of the present invention is configured by a large screen display 112 and a display mask 114, which covers and hides a portion thereof. The display mask 114 is disposed at a position only an appropriate distance away from a display surface 116. The display mask 114 has a hole 118, and only through that portion can the display surface 116 of display 112 be seen. By introducing such display mask 114, the region visible upon the display surface differs depending on the viewpoint position of the user. As a result, it becomes possible to provide different content for every user.

Abstract: An apparatus optically reproduces FM electric signals from the recording medium recorded with said electric signals in the form of a change in refraction index. The apparatus is so constructed that a pair of laser beams are incident on the recording medium at substantially the same point with an angle defined between the laser beams; a diffracted light obtained by causing each of said beams to be diffracted, upon being transmitted through the recording medium, in accordance with the phase change pattern thereof is overlapped on a non-diffracted light obtained by causing the each of said beams to be transmitted through the recording medium without being diffracted; and optically phase-modulated signals are detected as a beat output produced by optical mixing of the diffracted light with the non-diffracted light, thus to reproduce a recorded signal.