Sharp Kabushiki Kaisha Corporation

Yukinori Nishitani

Kenji Ohta

Akira Takahashi

Junji Hirokane

Hiroyuki Katayama

Michinobu Mieda

Tetsuya Inui

Kazuo Van

Yukio Kurata

Yoshio Yoshida

Takahiro Miyake

An optical recording element comprising a recording medium which includes an information recording area formed at every unit in a non-continuous condition, the recording medium further including sample pits disposed at intervals of a fixed distance for providing basic information about the locations of the recording units in same track. Each sample pit comprises a plurality of pits disposed next to the sequence of the recording units so that the spacing between the pits differs from the spacing between the recording units. At least one of the plurality of pits is a long-sized inclined pit which is inclined at an angle in the range of 6.degree. to 80.degree. to a recording track. A driving system for driving the optical recording element for recording information in the non-continuous recording area or erasing information stored therein with a light beam the output of which is varied as required and checking whether said recording or erasing has been correctly performed, within a very short time in which the light beam passes through the non-continuous recording area. By using the optical recording element in combination with its driving system, the processing speed for reducing, erasing and verifying these functions can be greatly improved and the irradiating position of the light beam at every recording unit can be correctly controlled.

Optical recording element and driving system

An optical pickup apparatus for reading out information from an optical disk. The optical pickup includes a light source; and an optical device having a grating pattern for splitting a light beam from said the source into a zero-order diffracted beam and plus and minus first-order diffracted beams. The grating pattern has the center portion and one or more side portions. The efficiency of the center portion for the zero-order diffracted beam is greater than the efficiency of the side portions for the zero-order diffracted beam.

Optical pickup apparatus

An optical recording element comprising a recording medium which includes an information recording area formed at every unit in a non-continuous condition, the recording medium further including sample pits disposed at intervals of a fixed distance for providing basic information about the locations of recording units in the same track. Each sample pit comprises a plurality of pits disposed next to the sequence of the recording units so that the spacing between the pits differs from the spacing between the recording units. At least one of the plurality of pits is a long-sized inclined pit which is inclined at an angle in the range of 6.degree. to 80.degree. to a recording track. A driving system for driving the optical recording element for recording information in the non-continuous recording area or erasing information stored therein with a light beam the output of which is varied as required and checking whether said recording or erasing has been correctly performed, within a very short time in which the light beam passes through the non-continuous recording area. By using the optical recording element in combination with its driving system, the processing speed for reducing, erasing and verifying these functions can be greatly improved and the irradiating position of the light beam at every recording unit can be correctly controlled.

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Neyagawa, Japan

Yukinori Nishitani