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US 6,608,801 B2Granted
Apparatus and method for position control of optical system, and storage and reproduction apparatus
AssigneeSony Corporation
InventorsIsao Ichimura, Koichiro Kishima, Kiyoshi Osato
Life of this patent
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Abstract
A position control apparatus of an optical system capable of positioning a lens at a high accuracy in a near-field optical system using a solid immersion lens. An objective lens 2 and a solid immersion lens are fixed to a lens holder 4. The lens holder 4 is moved by a tracking actuator 5 in the tracking direction of an optical disk 51 and is moved by a focus actuator 8 in the focus direction. The focus actuator 8 is controlled on the basis of the electrostatic capacitance occurring between the solid immersion lens 3 and the optical disk 51.
Claims28
A position control apparatus of an optical system comprising
- an optical system forming a near-field with an optical storage medium and irradiating a converging light beam to the optical storage medium, wherein an objective lens converging the light beam to be irradiated on the optical storage medium and a solid immersion lens with an electrode formed on a surface facing the optical storage medium and irradiating the light beam converged by the objective lens to the optical storage medium are fixed by a holding means,
- an actuator for moving the holding means in the focus direction perpendicularly intersecting the storage surface of the optical storage medium, and
- a control circuit for controlling the actuator on the basis of electrostatic capacitance formed by the electrode and the optical storage medium and of a reflected light from the optical storage medium so that the distance between the solid immersion lens and the optical storage medium becomes within the region where the near-field is formed.
A position control apparatus of an optical system comprising
- an optical system forming a near-field with an optical storage medium and irradiating a converging light beam to the optical storage medium, wherein an objective lens converging the light beam to be irradiated on the optical storage medium and a solid immersion lens with an electrode formed on a surface facing the optical storage medium and irradiating the light beam converged by the objective lens to the optical storage medium are fixed by a holding means,
- a first actuator for moving the holding means in a focus direction perpendicularly intersecting the storage surface of the optical storage medium,
- a second actuator for moving the holding means in a radial direction of the optical storage medium,
- a first control circuit for controlling the first actuator on the basis of electrostatic capacitance formed by the electrode and the optical storage medium and of a reflected light from the optical storage medium so that the distance between the solid immersion lens and the optical storage medium becomes within the region where the near-field is formed, and
- a second control circuit for controlling the second actuator on the basis of the reflected light from the optical storage medium.
2 more elements
A position control apparatus of an optical system comprising
- an optical system forming a near-field with an optical storage medium and irradiating a converging light beam to the optical storage medium, wherein an objective lens converging the light beam to be irradiated on the optical storage medium and a solid immersion lens with an electrode formed on a surface facing the optical storage medium and irradiating the light beam converged by the objective lens to the optical storage medium are fixed by a holding means,
- a first actuator for moving the holding means in the focus direction perpendicularly intersecting the storage surface of the optical storage medium,
- a second actuator for moving the holding means in the direction perpendicularly intersecting the signal storage direction on the optical storage medium,
- a first control circuit for controlling the first actuator on the basis of electrostatic capacitance formed by the electrode and the optical storage medium and of a reflected light from the optical storage medium so that the distance between the solid immersion lens and the optical storage medium is within the region where the near-field is formed, and
- a second control circuit for controlling the second actuator on the basis of the reflected light from the optical storage medium,
- a first moving means for moving an optical head carrying at least the optical system, the first actuator, and the second actuator in the direction perpendicularly intersecting the signal storage direction on the optical storage medium, and
- a second moving means for moving an optical head carrying at least the optical system, the first actuator, and the second actuator in the signal storage direction on the optical storage medium.
4 more elements
A position control method of an optical system for controlling a distance with an optical system which forms a near-field with an optical storage medium and irradiates a converging light beam to the optical storage medium and the optical storage medium by moving the optical system in the focus direction perpendicularly intersecting the storage surface of the optical storage medium, said method comprising a step of
- controlling an actuator for moving a holding means, fixing an objective lens converging the light beam to be irradiated to the optical storage medium and a solid immersion lens with an electrode formed on a surface facing the optical storage medium and irradiating the light beam converged by the objective lens to the optical storage medium, in the focus direction on the basis of electrostatic capacitance formed by the electrode and the optical storage medium and of a reflected light from the optical storage medium so that the distance between the solid immersion lens and the optical storage medium is within the region where the near-field is formed.
A position control method of an optical system for controlling the distance between an optical system which forms a near-field with an optical storage medium and irradiates a converging light beam to the optical storage medium and the optical storage medium by moving the optical system in a focus direction perpendicularly intersecting the storage surface of the optical storage medium, said method comprising the steps of
- controlling a first actuator for moving a holding means, fixing an objective lens converging the light beam to be irradiated to the optical storage medium and a solid immersion lens with an electrode formed on a surface facing the optical storage medium and irradiating the light beam converged by the objective lens to the optical storage medium, move in the focus direction on the basis of electrostatic capacitance formed by the electrode and the optical storage medium and of a reflected light from the optical storage medium so that the distance between the solid immersion lens and the optical storage medium becomes within the region where the near-field is formed and
- controlling a second actuator and moving the holding means in the radial direction of the optical storage medium on the basis of a reflected light from the optical storage medium.
A position control method of an optical system for controlling the distance between an optical system which forms a near-field with an optical storage medium and irradiates a converging light beam to the optical storage medium and the optical storage medium by moving the optical system in a focus direction perpendicularly intersecting the storage surface of the optical storage medium, said method comprising the steps of
- controlling a first actuator for moving a holding means, fixing an objective lens converging the light beam to be irradiated to the optical storage medium and a solid immersion lens with an electrode formed on a surface facing the optical storage medium and irradiating the light beam converged by the objective lens to the optical storage medium, move in the focus direction on the basis of electrostatic capacitance formed by the electrode and the optical storage medium and of a reflected light from the optical storage medium so that the distance between the solid immersion lens and the optical storage medium becomes within the region where the near-field is formed,
- moving an optical head carrying at least the optical system, the first actuator, and a second actuator in a direction perpendicularly intersecting the signal storage direction on the optical storage medium, and
- moving an optical head carrying at least the optical system, the first actuator, and the second actuator in the signal storage direction on the optical storage medium.
A storage and reproduction apparatus comprising a light source,
- an optical system forming a near-field with an optical storage medium and irradiating a converging light beam to the optical storage medium, wherein an objective lens converging the light beam to be irradiated to the optical storage medium and a solid immersion lens with an electrode formed on a surface facing the optical storage medium and irradiating the light beam converged by the objective lens to the optical storage medium are fixed by a holding means,
- an actuator for moving the holding means in a focus direction perpendicularly intersecting the storage surface of the optical storage medium,
- a control circuit for controlling the actuator on the basis of electrostatic capacitance formed by the electrode and the optical storage medium and of a reflected light from the optical storage medium so that the distance between the solid immersion lens and the optical storage medium becomes within the region where the near-field is formed,
- a motor for rotating the optical storage medium when storing information and reproducing information,
- an intensity modulation circuit for modulating the intensity of the light from the light source according to the information to be stored when storing information, and
- an information detection circuit for detecting the recorded information from the reflected light reflected by the optical storage medium when reproducing information.
3 more elements
A storage and reproduction apparatus comprising a light source,
- an optical system forming a near-field with an optical storage medium and irradiating a converging light beam to the optical storage medium, wherein an objective lens converging the light beam to be irradiated to the optical storage medium and a solid immersion lens with an electrode formed on a surface facing the optical storage medium and irradiating the light beam converged by the objective lens to the optical storage medium are fixed by a holding means,
- a first actuator for moving the holding means in the focus direction perpendicularly intersecting the storage surface of the optical storage medium,
- a second actuator for moving the holding means in the radial direction of the optical storage medium,
- a first control circuit for controlling the first actuator on the basis of electrostatic capacitance formed by the electrode and the optical storage medium and of a reflected light from the optical storage medium so that the distance between the solid immersion lens and the optical storage medium becomes within the region where the near-field is formed,
- a second control circuit for controlling the second actuator on the basis of the reflected light from the optical storage medium,
- a motor for rotating the optical storage medium when storing information and reproducing information,
- an intensity modulation circuit for modulating the intensity of the light from the light source according to the information to be stored when storing information, and
- an information detection circuit for detecting the stored information from the reflected light reflected by the optical storage medium when reproducing information.
5 more elements
A storage and reproduction apparatus comprising a light source,
- an optical system forming a near-field with an optical storage medium and irradiating a converging light beam to the optical storage medium, wherein an objective lens converging the light beam to be irradiated to the optical storage medium and a solid immersion lens with an electrode formed on a surface facing the optical storage medium and irradiating the light beam converged by the objective lens to the optical storage medium are fixed by a holding means,
- a first actuator for moving the holding means in a focus direction perpendicularly intersecting the storage surface of the optical storage medium,
- a second actuator for moving the holding means in a direction perpendicularly intersecting the signal storage direction on the optical storage medium,
- a first control circuit for controlling the first actuator on the basis of electrostatic capacitance formed by the electrode and the optical storage medium and of a reflected light from the optical storage medium so that the distance between the solid immersion lens and the optical storage medium becomes within the region where the near-field is formed,
- a second control circuit for controlling the second actuator on the basis of the reflected light from the optical storage medium,
- a first moving means for moving an optical head carrying at least the optical system, the first actuator, and the second actuator in the direction perpendicularly intersecting the signal storage direction on the optical storage medium,
- a second moving means for moving an optical head carrying at least the optical system, the first actuator, and the second actuator in the signal storage direction on the optical storage medium,
- an intensity modulation circuit for modulating the intensity of the light from the light source according to the information to be stored when storing information, and
- an information detection circuit for detecting the stored information from the reflected light reflected by the optical storage medium when reproducing information.
6 more elements
Dependencies are inferred from the claim text.