Claims
- 1. An optical apparatus for use in an optical pickup for preventing crosstalk between adjacent tracks on the surface of an optical disk comprising:
- a semiconductor laser for emitting a light beam;
- a collimate lens to obtain a parallel beam from the light beam emitted from the semiconductor laser;
- an objective for focusing the parallel beam onto the surface of the optical disk;
- a light receiving element for detecting a light reflected from the surface of the optical disk having pits formed thereon arranged along the tracks for recording a signal;
- wherien a first angular width of the light beam emitted from the laser and incident on the collimate lens in a first direction at an intensity half of maximum intensity is in the range of 9.degree. to 12.degree.; a second angular width of the beam emitted from the laser and incident on the collimate lens in a second direction perpendicular to the first direction at an intensity half of maximum intensity is about three times the value of the first angular width, and a numeric aperture value of said collimate lens is in the range of 0.14 to 0.2; and
- wherein a diameter of a spot formed by the parallel light on the surface is about 1.5 .mu.m, thereby focusing the spot on a single track on the surface.
- 2. An optical apparatus according to claim 1, wherein a distribution of an amount of light of the parallel beam obtained from the collimate lens is a Gaussian distribution.
- 3. An optical apparatus according to claim 1, wherein a diffraction grid having no apodizing filter is in an optical path between the laser and the collimating laser.
Priority Claims (1)
Number |
Date |
Country |
Kind |
62-101489 |
Apr 1987 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 07/141,325, filed 01/06/88, abandoned.
US Referenced Citations (10)
Continuations (1)
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Number |
Date |
Country |
Parent |
141325 |
Jan 1988 |
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