| 摘要 |
PURPOSE: An optical disc device, an optical pick-up, a method of producing a pre-format signal, and a program are provided to reduce the effect due to slight light between layers and to stably detect a pre-format signal established previously on the recording track of an optical disc. CONSTITUTION: An optical disc device(1) comprises a light source, an object lens(8), an optical pick-up(7), a condensing lens, a hologram element, and a signal processing unit(4). The light source triggers a light beam. The object lens condenses the light beam on one of one or more recording layers. The 2-shaft actuator(9) of the optical pick-up performs the focus control and the tracking control of the object lens based on a driving signal. The condensing lens condenses the light beam reflected by the optical disc. The hologram element makes the reflected light beam go straight or diffracts it. The signal processing unit creates a pre-format signal indicating the pre-format information recorded previously on the track groove of the optical disc.
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