| 摘要 |
<p>1490223 Optical playback of flexible disc records PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 26 Nov 1974 [29 Nov 1973] 51130/74 Heading G5R A playback beam modulated by information recorded on one face 5 of a rotating flexible disc record 1 passes through the thickness of the disc and an optical system 4, 3 to a detector; the disc 1 passes between two shoes 8, 7 which form air bearings with the respective faces 5, 6 of the disc and, in order to maintain constant the distance between the optical system and the apparent plane I of the recorded information despite variations in the thickness of the disc 1, the ratio of the respective stiffnesses of these two air bearings is arranged to be 1 : (n-1), where n is the refractive index of the disc 1.</p> |
