Optical pickup, optical disc apparatus, integrated coupling lens, integrated prism, and optical information equipment

An optical pickup comprising:

• a first objective lens configured to focus the laser beam at a first light path on a first information recording medium;
• a second objective lens configured to focus the laser beam at a second light path on a second information recording medium;
• a first coupling lens disposed at such a location that the optical axis of the laser beam at the first light path and the optical axis of the laser beam at the second light path extend substantially in parallel to each other configured to convert the laser beam at the first light path into substantially a collimated light beam;
• and
• a second coupling lens disposed at such the location that the optical axis of the laser beam at the first light path and the optical axis of the laser beam at the second light path extend substantially in parallel to each other configured to convert the laser beam at the second light path into substantially a collimated light beam, wherein
• L<(Dc1/2)+(Dc2/2) is satisfied
• where Dc1 is the diameter of the first coupling lens, Dc2 is the diameter of the second coupling lens, and L is the distance between the optical axis of the first coupling lens and the optical axis of the second coupling lens.

An optical pickup comprising:

• a first light source configure to emit a first laser beam at a wavelength λ1;
• a light path switching unit configured to switch the first laser beam emitted from the first light source between a first light path and a second light path;
• a first objective lens disposed across the first light path configured to focus the first laser beam at its numerical aperture of NA1 on a first information recording medium which has a first transparent substrate thickness t1;
• and
• a second objective lens disposed across the second light path configured to focus the first laser beam at its numerical aperture of NA2 (NA1>NA2) on a second information recording medium which has a second transparent substrate thickness t2 (t1<t2), wherein
• the first objective lens and the second objective lens are arranged along the radial direction of either the first information recording medium or the second information recording medium, and
• the first objective lens is located at the outer side of either the first information recording medium or the second information recording medium than the second objective lens.

An optical pickup comprising:

• a first light source configured to emit a first laser beam at a wavelength λ1;
• a first objective lens configured to focus the first laser beam on a first information recording medium which has a first transparent substrate thickness t1;
• a second light source configured to emit a second laser beam at a wavelength λ2;
• a second objective lens configured to focus the second laser beam on a second information recording medium which has a second transparent substrate thickness t2 different from the first transparent substrate thickness t1;
• a first reflective surface provided between the first light source and the first objective lens configured to bend the optical axis of the first laser beam so as to extend substantially vertical to the information recording surface of the first information recording medium;
• and
• a second reflective surface provided between the second light source and the second objective lens configured to bend the optical axis of the second laser beam so as to extend substantially vertical to the information recording surface of the second information recording medium, wherein
• the first reflective surface and the second reflective surface are arranged substantially in parallel with each other.

An optical pickup comprising:

• a first light source configured to emit a first laser beam at a wavelength λ1;
• a first objective lens configured to focus the first laser beam on a first information recording medium;
• a second light source configured to emit a second laser beam at a wavelength λ2;
• a second objective lens configured to focus the second laser beam on a second information recording medium which is different from the first information recording medium;
• an optical axis aligning surface configured to reflect one of the two light beams and transmit the other, the two light beams being the first laser beam emitted from the first light source and directed to the first objective lens and the second laser beam emitted from the second light source and directed to the second objective lens, and thus to align the optical axis of the first laser beam and the optical axis of the second laser beam substantially with each other;
• and
• an optical axis separating surface configured to reflect one of the first and second laser beams and transmit the other thus to split their optical axes aligned substantially with each other by the optical axis aligning surface into each other, wherein
• the first laser beam separated by the optical axis separating surface is directed to the first objective lens while the second laser beam separated by the optical axis separating surface is directed to the second objective lens.

An optical pickup comprising:

• a light source configured to emit a laser beam at a diverged light;
• an advancing path coupling lens disposed across the advancing path configured to convert the laser beam of the diverged light to substantially a collimated light beam;
• a light path switching unit configured to switch the laser beam at the collimated light beam produced by the coupling lens at the advancing path between a first light path and a second light path;
• a first objective lens disposed across the first light path configured to focus the laser beam on a first information recording medium which has a first transparent substrate thickness;
• a second objective lens disposed across the second light path configured to focus the laser beam on a second information recording medium which has a second transparent substrate thickness different from the first transparent substrate thickness and thus is different from the first information recording medium;
• a returning path coupling lens disposed across the returning path configured to convert a first reflected laser beam formed by the reflection of the laser beam on the first information recording medium and a second reflected laser beam formed by the reflection of the laser beam on the second information recording medium into a converged light;
• and
• a photo detector configure to receive the reflected laser beam converged by the returning path coupling lens.

An integrated coupling lens for use in an optical pickup having a first objective lens for focusing the laser beam at a first light path on a first information recording medium and a second objective lens for focusing the laser beam at a second light path on a second information recording medium, comprising:

• a first coupling lens configured to convert the laser beam at the first light path into substantially a collimated light beam;
• and
• a second coupling lens configured to convert the laser beam at the second light path into substantially a collimated light beam, wherein
• the first coupling lens and the second coupling lens are arranged integrally of a single unit and disposed at such a location that the optical axis of the first light path and the optical axis of the second light path extend substantially in parallel with each other.

An optical disc apparatus comprising:

• an optical pickup including:
• a first light source configured to emit a first laser beam at a wavelength λ1;
• a first objective lens configured to focus the first laser beam on a first information recording medium which has a first transparent substrate thickness t1;
• a first coupling lens disposed between the first light source and the first objective lens configured to convert the first laser beam into substantially a collimated light beam;
• a second light source configured to emit a second laser beam at a wavelength λ2;
• a second objective lens configured to focus the second laser beam on a second information recording medium which has a second transparent substrate thickness t2 different from the first transparent substrate thickness t1;
• and
• a second coupling lens disposed between the second light source and the second objective lens configured to convert the second laser beam into substantially a collimated light beam;
• a motor configured to rotate the first information recording medium and the second information recording medium;
• and
• a moving mechanism configured to move the optical pickup along the radial direction of the first information recording medium or the second information recording medium, which all are mounted on an optical platform,
• the optical platform being divided into two regions by a plane which extends substantially perpendicular to the first information recording medium or the second information recording medium and in which the center axis of rotation of the motor and the straight line parallel with the direction of the movement of the optical pickup are present, and
• either the first light source or the second light source being disposed in one of the two regions.

An optical disc apparatus comprising:

• an optical pickup;
• a motor configured to rotate an information recording medium;
• and
• a controller configured to control the action of the optical pickup and the motor,
• the optical pickup comprising:
• a first light source configured to emit a first laser beam at a wavelength λ1;
• a light path switching unit configured to switch the first laser beam emitted from the first light source between a first light path and a second light path;
• a first coupling lens disposed across the first light path configured to convert the first laser beam to substantially a collimated light beam;
• a first objective lens disposed across the first light path configured to focus the first laser beam passed through the first coupling lens on a first information recording medium which has a first transparent substrate thickness;
• a second coupling lens disposed across the second light path configured to convert the first laser beam to substantially a collimated light beam;
• and
• a second objective lens disposed across the second light path configured to focus the first laser beam passed through the second coupling lens on a second information recording medium which has a second transparent substrate thickness different from the first transparent substrate thickness and is different in the type from the first information recording medium,
• the light path switching unit being arranged to switch the light path of the first laser beam through selectively transmitting and reflecting the first laser beam emitted from the first light source,
• the first coupling lens being configured to convert a first reflected laser beam from the first information recording medium into a converged light;
• and
• the second coupling lens being configured to convert a second reflected laser beam from the second information recording medium into a converged light.

An optical information equipment comprising:

• an optical disc apparatus;
• and
• a calculating part configured to calculate data played back by the optical disc apparatus,
• the optical disc apparatus comprising:
• an optical pickup including:
• a first light source configured to emit a first laser beam at a wavelength λ1;
• a first objective lens configured to focus the first laser beam on a first information recording medium which has a first transparent substrate thickness t1;
• a first coupling lens disposed between the first light source and the first objective lens configured to convert the first laser beam into substantially a collimated light beam;
• a second light source configured to emit a second laser beam at a wavelength λ2;
• a second objective lens configured to focus the second laser beam on a second information recording medium which has a second transparent substrate thickness t2 different from the first transparent substrate thickness t1;
• and
• a second coupling lens disposed between the second light source and the second objective lens configured to convert the second laser beam into substantially a collimated light beam;
• a motor configured to rotate the first information recording medium and the second information recording medium;
• and
• a moving mechanism configured to move the optical pickup along the radial direction of the first information recording medium or the second information recording medium, which all are mounted on an optical platform,
• the optical platform being divided into two regions by a plane which extends substantially perpendicular to the first information recording medium or the second information recording medium and in which the center axis of rotation of the motor and the straight line parallel with the direction of the movement of the optical pickup are present, and
• either the first light source or the second light source being disposed in one of the two regions.

An optical information equipment comprising:

• an optical disc apparatus;
• and
• a calculating part configured to calculate data played back by the optical disc apparatus,
• the optical disc apparatus comprising:
• an optical pickup;
• a motor configured to rotate an information recording medium;
• and
• a controller configured to control the action of the optical pickup and the motor,
• the optical pickup comprising:
• a first light source configured to emit a first laser beam at a wavelength λ1;
• a light path switching unit configured to switch the first laser beam emitted from the first light source between a first light path and a second light path;
• a first coupling lens disposed across the first light path configured to convert the first laser beam to substantially a collimated light beam;
• a first objective lens disposed across the first light path configured to focus the first laser beam passed through the first coupling lens on a first information recording medium which has a first transparent substrate thickness;
• a second coupling lens disposed across the second light path configured to convert the first laser beam to substantially a collimated light beam;
• and
• a second objective lens disposed across the second light path configured to focus the first laser beam passed through the second coupling lens on a second information recording medium which has a second transparent substrate thickness different from the first transparent substrate thickness and is different in the type from the first information recording medium,
• the light path switching unit being arranged to switch the light path of the first laser beam through selectively transmitting and reflecting the first laser beam emitted from the first light source,
• the first coupling lens being configured to convert a first reflected laser beam from the first information recording medium into a converged light;
• and
• the second coupling lens being configured to convert a second reflected laser beam from the second information recording medium into a converged light.