OPTICAL RECORDING AND REPRODUCING DEVICE

摘要

PURPOSE:To attain the optical record or reproduction by constituting an optical system so that the beam delivered from one of both lasers is put in focus with the beam delivered from the other laser put out of focus respectively. CONSTITUTION:Two slot positions are set to an objective lens 7 and then selected by an actuator 71. A lens system is set so that one of both beams (k) and (i) is dispersed with the other focused respectively. One of both beams (k) and (i) is stopped down to the minimum spot at one of both slot positions together with the other beam rather blurred respectively and vice versa at the other slot position. For this purpose, both slot positions are especially set. Thus the slot position is selected in a record mode so that the spot (k) is increased with the spot (i) minimized respectively. In addition, the focus control is carried out to minimize the spot of the beam (k) and therefore the spot of the beam (i) is put out of focus together with increase of the spot diameter. Thus the slow cooling time is secured with the spread beam (i) and the information recorded on a medium is erased.