JP4817127B2 - Optical pickup device - Google Patents

Description

  The present invention relates to an optical pickup device capable of recording and / or reproducing information with respect to an optical disc.

In a general optical pickup device that records and / or reproduces information with respect to an optical disk such as a CD or a DVD, the information recording surface of the optical disk is irradiated with a light beam from a semiconductor laser via a condensing optical system including an objective lens. In this configuration, the reflected light from the information recording surface is incident on the same objective lens, then branched from the optical path from the semiconductor laser, and guided to the photodetector through the sensor optical system. . However, in the case of such an optical pickup device, there is a problem that the condensing optical system and the sensor optical system must be arranged in close proximity, and the configuration is increased in size.
JP 2000-30306 A

  On the other hand, Patent Document 1 discloses an information reproducing apparatus that records and / or reproduces information using near-field light. In the technique of Patent Document 1, the near field light is irradiated onto the data pit, and the reflected light is received by the reproduction light detector via the condensing optical system disposed between the reproduction probe and the information recording medium. It has become. However, even in such a configuration, there is a possibility that the reproducing probe and the condensing optical system interfere with each other, which leads to an increase in size of the optical pickup device.

  The present invention has been made in view of the problems of the prior art, and an object thereof is to provide an optical pickup device having a simple configuration.

The optical pickup device according to the first aspect of the present invention responds to recorded information when a light beam for recording and / or reproducing information is incident on a rotating optical disk in a direction along the axis of the optical disk. An optical pickup device for recording and / or reproducing information with respect to an optical disc in which a light beam propagates in a radial direction along a protective substrate ,
An optical detector is provided in a radial direction of the optical disc, and information is recorded and / or reproduced by detecting light emitted from the outer edge or the inner edge of the optical disc by being guided in the optical disc by the optical detector. It is characterized by.

  According to the present invention, since the light beam corresponding to the recorded information is emitted in the direction orthogonal to the axis line on the optical disc, the light beam can be received by providing a photodetector in the radial direction of the optical disc. As a result, the degree of freedom of installation of the photodetector is improved, and the optical pickup device can be simplified and downsized.

  According to a specific aspect of the present invention, the photodetector is disposed radially outside the optical disc.

  According to a specific aspect of the present invention, the reflecting means is formed on the periphery of the opening formed on the radially inner side of the optical disc.

  According to a specific aspect of the present invention, the photodetector is disposed radially inside the optical disc.

  According to a specific aspect of the present invention, reflecting means is formed on the outer peripheral edge of the optical disc.

The optical pickup device according to the second aspect of the present invention responds to recorded information when a light beam for recording and / or reproducing information is incident on a rotating optical disc in a direction along the axis of the optical disc. An optical pickup device for recording and / or reproducing information with respect to an optical disc in which a light beam propagates in a radial direction along a protective substrate ,
A mirror disposed radially inward of the optical disc;
An optical detector for receiving the light beam reflected by the mirror is provided , and the optical detector detects light after being guided by the optical disc and reflected from the inner edge of the optical disc after being reflected by the mirror. And / or performing reproduction .

  According to the present invention, in the optical disc, a light beam corresponding to recorded information is emitted in a direction orthogonal to the axis, so that a mirror is provided on the radially inner side of the optical disc, and light that receives the light beam reflected by the mirror is received. By providing the detector, it is possible to receive such a light beam, thereby improving the degree of freedom of installation of the photodetector and simplifying and downsizing the optical pickup device.

  According to a specific aspect of the present invention, reflecting means is formed on the outer peripheral edge of the optical disc.

  According to the present invention, an optical pickup device having a simple configuration can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The optical pickup device PU1 according to the present embodiment can record and / or reproduce information with respect to an optical disc OD capable of recording / reproducing information. FIG. 1 is a diagram showing a schematic configuration of an optical pickup device PU1 according to the present embodiment. FIG. 2 is a diagram of the configuration of FIG. 1 viewed in the direction of arrow II.

  In the present embodiment, scattered light and light emission generated according to the pits on the information recording surface are detected. Since scattered light and light emission propagate in directions other than the incident direction, some of them propagate while being totally reflected in the optical disk.

  Further, a reflection film as a reflection means is formed on the periphery of the central opening AP of the optical disc OD. The photodetector PD is disposed in the vicinity of the outer periphery of the optical disc OD.

  In FIG. 1, the light beam emitted from the semiconductor laser LD passes through the collimator COL, enters the optical disc OD via the objective lens OBJ, and reaches the information recording surface through the protective substrate. The light beam reflected according to the pits on the information recording surface propagates along the protective substrate in the direction perpendicular to the axis of the optical disk OD and is emitted from the outer edge of the optical disk OD. By receiving this light with the photodetector PD, information can be recorded and / or reproduced.

  As shown in FIG. 2, the light flux scattered and emitted in accordance with the pits on the information recording surface propagates in various directions, but since the reflection film is formed on the periphery of the central aperture AP, it is efficient. The luminous flux is collected and can be received by the photodetector PD.

  According to the present embodiment, since a light beam according to recorded information is emitted in the direction orthogonal to the axis line on the optical disc OD, the light detector PD is provided on the outer side in the radial direction of the optical disc OD, so Light can be received immediately after being emitted from the OD, and since the sensor optical system is not used, stray light can be prevented from being generated. Furthermore, the degree of freedom in installing the photodetector PD is improved, and the optical pickup device is simplified and miniaturized. Can be achieved. Although the single photodetector PD is shown in FIG. 2, a plurality of photodetectors may be arranged, or may be arranged all around the optical disc OD. Thereby, the light receiving sensitivity is improved.

  FIG. 3 is a diagram illustrating a schematic configuration of an optical pickup device PU2 according to another embodiment. FIG. 4 is a diagram of the configuration of FIG. 3 as viewed in the direction of arrow IV. FIG. 5 is a diagram showing the structure of the outer edge of the optical disk indicated by the arrow V in FIG.

  In the present embodiment, as shown in FIG. 3, the photodetector PD is disposed in the central opening AP of the optical disc OD. The photodetector PD is preferably integrated in a clamp part (not shown) that holds and rotates the optical disc OD. Further, as shown in FIG. 5, a reflection film RM as a reflection means is formed on the outer edge of the optical disc OD. Since other configurations are the same as those in the above-described embodiment, the description thereof is omitted.

  According to the present embodiment, by providing the photodetector PD on the inner side in the radial direction of the optical disc OD, immediately after the light flux reflected according to the pits on the information recording surface and propagating in the radial direction is emitted from the optical disc OD. Since the sensor optical system is not used, the generation of stray light and the like can be suppressed, and the degree of freedom of installation of the photodetector PD can be improved, and the optical pickup device can be simplified and downsized. . At this time, since the reflection film RM is formed on the outer peripheral edge of the optical disc OD, the light beam traveling outward in the radial direction is reflected by the reflection film RM, so that the photodetector PD can efficiently receive the light.

  FIG. 6 is a view similar to FIG. 5 showing a modification of the present embodiment. In this modification, a prism surface PS having an apex angle of approximately 90 degrees is formed on the outer edge of the optical disc OD. The light beam traveling outward in the radial direction is reflected by the prism surface PS, so that it can be efficiently received by the photodetector PD.

  FIG. 7 is a diagram showing another modification. In the present modification, instead of providing the photodetector PD at the central aperture AP, the conical mirror M is arranged and the photodetector PD is arranged above the axial direction in the embodiment shown in FIG. Is different. According to this modification, the light beam that is reflected according to the pits on the information recording surface and propagates radially inward can be reflected by the mirror M and received by the photodetector PD thereabove. As described above, if the mirror M is arranged in the central aperture AP, it is only necessary to provide an electrical wiring for the fixed photodetector PD, and it is not necessary to provide an electrical wiring in the rotating portion, so the configuration is simple. It becomes.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate.

It is a figure which shows schematically the structure of optical pick-up apparatus PU1. It is the figure which looked at the structure of FIG. 1 in the arrow II direction. It is a figure which shows schematically the structure of optical pick-up apparatus PU2. It is the figure which looked at the structure of FIG. 3 in the arrow IV direction. FIG. 5 is a diagram illustrating a structure of an outer edge of the optical disc indicated by an arrow V in FIG. 4. It is a figure similar to FIG. 5 which shows the modification of this Embodiment. It is a figure which shows another modification.

Explanation of symbols

AP Center aperture COL Collimator LD Semiconductor laser M Mirror OBJ Objective lens OD Optical disc PD Photodetector PS Prism surface PU1 Optical pickup device PU2 Optical pickup device RM Reflective film

Claims (7)

When a light beam for recording and / or reproducing information is incident on a rotating optical disk in a direction along the axis of the optical disk, the light beam corresponding to the recorded information is radially along the protective substrate. An optical pickup device for recording and / or reproducing information on an optical disc adapted to propagate ,
An optical detector is provided in a radial direction of the optical disc, and information is recorded and / or reproduced by detecting light emitted from the outer edge or the inner edge of the optical disc by being guided in the optical disc by the optical detector. An optical pickup device characterized by the above.   The optical pickup device according to claim 1, wherein the photodetector is disposed on the outer side in the radial direction of the optical disc.   3. The optical pickup device according to claim 2, wherein a reflection means is formed at a peripheral edge of the opening formed on the inner side in the radial direction of the optical disc. The optical pickup device according to claim 1 , wherein the optical detector is disposed radially inward of the optical disc.   5. The optical pickup device according to claim 4, wherein reflecting means is formed on an outer peripheral edge of the optical disc. When a light beam for recording and / or reproducing information is incident on a rotating optical disk in a direction along the axis of the optical disk, the light beam corresponding to the recorded information is radially along the protective substrate. An optical pickup device for recording and / or reproducing information on an optical disc adapted to propagate ,
A mirror disposed radially inward of the optical disc;
An optical detector for receiving the light beam reflected by the mirror is provided , and the optical detector detects light after being guided by the optical disc and reflected from the inner edge of the optical disc after being reflected by the mirror. And / or reproducing .   7. The optical pickup device according to claim 6, wherein reflecting means is formed on an outer peripheral edge of the optical disc.