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

Claim 15:
16. A method implemented by a detection apparatus, wherein the method comprises:
receiving, by a beam splitter, an incident pulsed laser beam, wherein a propagation direction of the incident pulsed laser beam is parallel to an optical axis of an objective lens;
splitting, by the beam splitter, the incident pulsed laser beam into a first beam and a second beam;
transmitting, by the beam splitter, the first beam in a first transmission direction that is perpendicular to the optical axis;
transmitting, by the beam splitter to the objective lens, the second beam in a second transmission direction that is parallel to the optical axis;
receiving, by a reflector, the first beam from the beam splitter;
reflecting, by the reflector, the first beam to obtain a third beam;
transmitting, by the reflector to the beam splitter, the third beam;
receiving, by an optical disc from the objective lens, the second beam;
reflecting, by the optical disc, the second beam to obtain a fourth beam;
transmitting, by the optical disc to the objective lens, the fourth beam;
receiving, by the optical disc, the third beam and the fourth beam from the beam splitter;
obtaining, by the optical disc, an interference beam from the third beam and the fourth beam;
determining, by the optical disc, an interference signal of the interference beam; and
determining, by a servo controller and based on the interference signal, whether a recording layer of the optical disc is located at a focal point of the objective lens.