| 摘要 |
PURPOSE:To execute the reproduction of information recorded with a high density in a high quality by setting a length in a direction corresponding to a tracking direction in a light-receiving area so as to be made approximately equal to the length in the direction corresponding to the tracking direction in a recording bit image image-formed on a light-receiving surface. CONSTITUTION:The title pick-up is equipped with image-forming means 9 and 10 to converge a reproducing light beam onto light-receiving surfaces 11a and 12a of photodetectors 11 and 12 and to image-form the recording bit images on the light-receiving surfaces. A length (a) in the direction corresponding to a tracking direction A-B in light-receiving areas 11b and 12b is set approximately equal to the length in the direction corresponding to the tracking direction in the recording bit images image-formed on the light-receiving surfaces. Consequently, an excessive light is not fetched from the photodetectors 11 and 12, only a necessary light is fetched, thereby, a modulation factor at the time of detecting a signal is made larger than a conventional one, and a signal quality can be improved. Thus, the reproduction of the image recorded with a high density can be executed in a high quality. |
