| 摘要 |
<p>The invention relates to an apparatus for reading from an optical recording medium (8), and more specifically to an apparatus suitable for reading from an optical recording medium (8) having a high data density. According to the invention, the apparatus has:
- a light source (2) for generating a first light beam (3);
- means (2') for generating a second light beam (3');
- one or more focusing means (7) for focusing the first light beam (3) and the second light beam (3') onto the optical recording medium (8) to form a first light spot (30, 30', 30", 40) and a second light spot (31, 31', 31", 41), wherein the second light spot (31, 31', 31", 41) is larger than the first light spot (30, 30', 30", 40) and physically and/or virtually encompasses the first light spot (30, 30', 30", 40);
- one ore more detectors (11) for detecting a first light beam (9) and a second light beam (9') reflected by the optical recording medium (8); and
- means for generating a data signal from the difference between the detected first and second reflected light beams (9, 9').</p> |
