US 5,313,447 AGranted

Optical head

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorsNobuo Takeshita, Kenjiro Kime, Teruo Fujita, Hiroo Shimegi, Kazuo Okada

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Abstract

An optical head for recording, reproducing or erasing data by emitting a light beam irradiated from a light source onto a recording medium. To reduce the height of the optical head, an optical axis shifting device is disposed between a light beam emitting device and a condensing device for condensing the light beam onto the recording medium. This optical axis shifting device shifts the first optical axis of the light beam from the light beam emitting device to a second optical axis positioned in parallel and spaced apart from each other. As the optical axis shifting device, there is preferable employed a prism having two reflecting faces lying in parallel, and the optical axis, after shifting is to be positioned downwardly of the position of the optical axis before shifting, thereby reducing the height of the optical head.

Claims14

Dependent claims

An optical head for optically recording, reproducing, or erasing data by condensing an irradiated light beam onto a recording medium and by forming minute optical spots thereon, said optical head comprising:

(a) light emitting means for emitting the light beam along a first optical axis, parallel to the recording medium;
(b) light condensing means for condensing the light beam onto the recording medium so as to form minute optical spots on the recording medium;
(c) optical axis shifting means including a first reflective surface for reflecting the light beam traveling along the first optical axis in a direction away from the recording medium and a second reflective surface for reflecting the light beam reflected by the first reflective surface so as to form a second optical axis parallel to said first optical axis;
and
(d) a light reflecting means for reflecting the light beam forming the second optical axis in a perpendicular direction toward the recording medium;
wherein the optical axis shifting means and the light reflecting means are disposed in the optical path between the light emitting means and the light condensing means.

3 more elements

Dependencies are inferred from the claim text.