| 摘要 |
<p>An optical scanning device comprises a laser which produces a light beam. The light beam is coupled by means of a half-silvered mirror (HS) to a recording medium (CD), and from there it passes through the half-silvered mirror (HS) and is reflected onto a photodetector (PD). The light beam is distributed over the photodector (PD) by a convex lens located behind the half-silvered mirror (HS). The convex lens, which is expensive and must be precisely adjusted, can be dispensed with. To this end, a transparent plate (P) is arranged between the half-silvered mirror (HS) and the photodetector (PD) at right angles to the half-silvered mirror (HS). To prevent the beam shift due to the half-silvered mirror (HS), the plate (P), for example a plate made of a material such as glass and having the same thickness as the half-silvered mirror (HS), is glued to a front face of the half-silvered mirror (HS). CD players, video disk players, DRAW disk players and magneto-optical appliances.</p> |
