Patent ID: 11887624
Assignee: HUAWEI TECHNOLOGIES CO., LTD.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 4:
5. An optical drive, comprising:
a light source emitter configured to emit an incident pulsed laser beam; and
a detection apparatus comprising:
an objective lens comprising an optical axis, wherein the optical axis comprises a first side and a second side, wherein the second side is opposite the first side;
a beam splitter located on the optical axis and configured to:
receive an incident pulsed laser beam, wherein a propagation direction of the incident pulsed laser beam is parallel to the optical axis;
split the incident pulsed laser beam into a first beam and a second beam;
transmit the first beam in a first transmission direction that is perpendicular to the optical axis; and
transmit, to the objective lens, the second beam in a second transmission direction that is parallel to the optical axis;

a reflector disposed on the first side, wherein a normal line of the reflector is perpendicular to the optical axis, and wherein the reflector is configured to:
receive the first beam from the beam splitter;
reflect the first beam to obtain a third beam; and
transmit, to the beam splitter, the third beam;

an optical disc comprising recording layers and configured to:
receive, from the objective lens, the second beam;
reflect the second beam to obtain a fourth beam; and
transmit, to the objective lens, the fourth beam;

a detector disposed on the second side and configured to:
receive the third beam and the fourth beam from the beam splitter;
obtain an interference beam from the third beam and the fourth beam; and
determine an interference signal of the interference beam; and

a servo controller coupled to the detector and configured to determine, based on the interference signal, whether one of the recording layers is located at a focal point of the objective lens.