KR19980016526A - Compatible Optical Pickup Device - Google Patents

Abstract

Disc-compatible optical pickup apparatus capable of interchangeably employing disc-type recording media having different formats.

The optical pickup apparatus includes a light source, a beam splitter for changing the path of incident light, an objective lens disposed between the light source and the disk to focus incident light on the disk, an actuator on which the objective lens is mounted, and a beam splitter reflected from the disk. A compatible optical pickup apparatus including a photodetector configured to receive light passing through and detect information and an error signal, wherein the objective lens is disposed at a predetermined distance from the actuator and has a first objective lens having a different numerical aperture. ; A second objective lens, the actuator comprising: a base on which a light source, a beam splitter, and a photodetector are located; A bobbin fixed to the objective lens and positioned on the base; A suspension whose one end is fixed on the base and movably supporting the bobbin; Magnetic drive means for driving the bobbin in the disc track radial direction and the disc focus direction, wherein the beam splitter is configured to be transported so that the light emitted from the light source is selectively directed to the first objective lens and the second objective lens. It features.

Description

Compatible Optical Pickup Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compatible optical pickup apparatus, and more particularly, to a disc compatible optical pickup apparatus capable of interchangeably employing disk-type recording media having different formats.

In general, an optical pickup device is a device for recording and / or reproducing information on a disc in a non-contact manner while moving in a radial direction of a disc, which is a recording medium.

Digital video disc players (DVDPs) and DVD-ROMs are attracting attention in the video / audio field as devices capable of high-density recording / playback. The optical pickup device employed in this DVDP should be capable of recording / reproducing information even when CDs as well as DVDs are used as recording media for compatibility.

On the other hand, the thickness of the DVD has been standardized to a standard different from the thickness of the CD due to mechanical disc tilt tolerance and objective lens numerical aperture. That is, the existing CD thickness is 1.2mm, while the DVD is 0.6mm. As described above, when the optical pickup device for DVD is applied to a CD because the thicknesses of the CD and the DVD are different from each other, spherical aberration occurs due to the thickness difference. This spherical aberration causes a problem of failing to obtain sufficient light intensity for recording the information signal or deterioration of the signal during reproduction.

The conventional compatible optical pickup device devised in consideration of these points is shown in FIG. 1. As shown in the figure, the light source 11, the objective lens 19, the beam splitter 15, the hologram element 17 and the photodetector 23 are roughly classified.

The light source 11 generates and emits laser light with a semiconductor laser. The objective lens 19 converges incident light so that an optical spot is formed on the recording surface of the optical disc 10. The beam splitter 15 is positioned on an optical path between the light source 11 and the objective lens 19 to prevent the light reflected from the optical disk from re-incident to the light source 11. That is, the beam splitter 15 passes most of the light 1 incident from the light source 11 toward the straight line and reflects the light incident from the objective lens 19 toward the photodetector 23. . The hologram element 17 is positioned on the optical path between the objective lens 19 and the beam splitter 15. The hologram element 17 separates the incident light 1 into a 0th order light 3 and a + 1st order light 5 and emits the light. The zero order light 3 is generally straight with respect to the incident light, and the + first order light 5 diverges. Therefore, the zero order light 3 and the +1 order light 5 pass through different positions of the objective lens 19 to form a focus at different positions. The zero shielding 3 is used for a DVD, and the + primary shielding 5 is used for a CD. The photodetector 23 receives light reflected from the recording surface of the optical disc 10 to detect an RF information signal, a track error signal, and a focus error signal.

The photodetector 23 is composed of a plurality of dividers to independently receive light, and adds and differentially amplifies the signals received at each divider to detect an RF information signal, a track error signal, and a focus error signal. do.

The optical pickup apparatus further includes a grating 13 and a collimating lens 15. The grating 13 is positioned between the light source 11 and the beam splitter to diffract the incident beam into a zero order diffraction beam, a ± first order diffraction beam, and the like. The collimating lens 16 is provided between the beam splitter 15 and the hologram element 17 to convert the incident divergent light into parallel light. An astigmatism lens 21 is provided between the beam splitter 15 and the photodetector 23. The astigmatism lens 21 generally has a semi-cylindrical shape, and when the distance between the objective lens 19 and the optical disc 10 is in focus, circular light is formed on the optical disc. Light is collected on the optical disk.

The optical pickup device separates the light emitted from the light source 11 into the zero order light 3 and the +1 order light 5 in the hologram element 17. Each of the separated lights 3 and 5 converges through the objective lens 19 and is formed on the optical disk. When the DVD 10a is employed as the optical disc 10, information is recorded / reproduced using the 0th light shield 3, and when the CD 10b is employed as the optical disk, the information is used by the +1 light shield 5 Record / play back.

The optical pickup device provided as described above selectively uses the 0th order light 3 and the + 1st order light 5 diffracted by the hologram element 17, so that the optical efficiency of the optical spot formed on the optical disk falls within approximately 50%. Since the light passes through the hologram element 17 toward the photodetector 23, the light received by the photodetector 23 is within about 25% of the light emitted from the light source 11. It has light efficiency.

In addition, the conventional optical pickup apparatus is provided with an actuator 30 as shown in FIG. The actuator has a base 31, a holder 32 fixed to the base 31, a bobbin 34 for fixing the objective lens 19, and the bobbin 34 to the holder 32. Suspension 33 and the magnetic drive means for moving the bobbin 34 in the track direction or the focus direction. The magnetic drive means includes a focus coil 35 wound on the outside of the bobbin 34, a tracking coil 36 attached to the focus coil 35, a pair of magnets 38a and 38b, A pair of outer yokes 39a and 39b installed on the base 31 and fixing each of the magnets 38a and 38b, and fixed to the base 31 and the focus coil 35 and the bobbin ( And a pair of inner yokes 37a and 37b positioned between 34 to guide movement of the bobbin 34. Here, the tracking coil 36 is attached to the focus coil 35 so as to face each of the magnets 38a and 38b.

The conventional actuator provided as described above is formed by winding the focus coil 35 and the tracking coil 36 on the bobbin 34 in the magnetic driving means, and the bobbin 34 and the focus coil 35. By providing the inner yokes 37a and 37b between them, there is a limit to the miniaturization of the actuator 30. In addition, the load of the optical pickup device in the radial direction of the disk is large because the mass of the coil is large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned points, and an object thereof is to provide a compatible optical pickup apparatus in which an optical efficiency is improved and a actuator is miniaturized by employing a pattern coil integrated with a bobbin.

1 is a block diagram showing an optical arrangement of a conventional compatible optical pickup device.

Figure 2 is a schematic perspective view showing a conventional optical pickup actuator.

3 is a block diagram showing an optical arrangement of a compatible optical pickup device according to an embodiment of the present invention.

4 is a block diagram showing an optical arrangement of a compatible optical pickup device according to another embodiment of the present invention.

5 is a schematic plan view of an optical pickup actuator according to an embodiment of the present invention;

6 is an enlarged partial view of FIG. 5.

7 is a schematic view for explaining a first pattern coil according to the present invention.

8 is a schematic view showing a second pattern coil according to the present invention;

9 is a schematic view showing a connecting portion according to the present invention.

Explanation of symbols for main parts of the drawings

10 ... disc 41 ... light source 42 ... collimating lens

43, 53 Beam splitter 44 First objective lens 45 Second objective lens

46,56 ... Astigmatism Lens 47 ... Photodetector 57 ... First Photodetector

58.2nd photodetector 60 ... actuator 61 ... base

63 ... holder 67 ... bobbin 69 ... suspension 71 ... first magnet 72 ... second magnet 73 ... first outer yoke 74 ... second outer yoke 81 ... magnetic layer 82 first dielectric layer 83 first pattern coil 84 second dielectric layer 85 second pattern coil

86 3rd Dielectric Layer 87 Connections 88 Contact Holes

In order to achieve the above object, the compatible optical pickup device according to the present invention includes a light source, a beam splitter for changing the traveling path of the incident light, an objective lens disposed between the light source and the disk to focus the incident light on the disk; A compatible optical pickup apparatus comprising an actuator on which the objective lens is mounted and a photodetector which receives light reflected from the disk and passes through the beam splitter and detects information and an error signal. A first objective lens and a second objective lens having different numerical apertures and spaced apart from each other by a predetermined distance from the actuator, and the beam splitter is configured to selectively receive the light emitted from the light source and the second objective lens and the second objective lens. It is characterized in that it is installed to be transported to the objective lens.

Preferably the actuator comprises a base on which the light source, beam splitter, and photodetector are located; A bobbin fixed to the objective lens and positioned on the base; A suspension fixed at one end to the base and movably supporting the bobbin; And magnetic drive means for driving the bobbin in a disc track radial direction and a disc focus direction.

The magnetic drive means may further comprise: a pair of first and second magnets installed on the base to face each of two sides of the bobbin parallel to the disc track radial direction; A magnetic layer deposited on a side facing each of the first and second magnets of the bobbin; A first dielectric layer deposited on the magnetic layer; A first pattern coil which is formed to be wrapped around the bobbin so that the bobbin is driven in a focus direction of the disk; A second dielectric layer formed on the side of the bobbin facing the first and second magnets on the first pattern coil and a portion facing the first magnet on the second dielectric layer and a portion facing the second magnet A second pattern coil provided at each pair so that the bobbin is driven in the disc track direction; And a third dielectric layer deposited on the second pattern coil.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic diagram illustrating an optical arrangement of a compatible optical pickup apparatus according to an embodiment of the present invention. As shown, the compatible optical pickup device includes, in its optical configuration, a light source 41, a beam splitter 43, an objective lens 44, 45, an actuator 60, and a photodetector 47. do. The light source 41 generates and emits laser light having a predetermined wavelength. This light source 41 consists of a conventional semiconductor laser. The beam splitter 43 is disposed on an optical path between the light source 41 and the disk 10 to guide the light incident from the light source 41 toward the disk 10 by reflecting the light. The light incident from the disk 10 is directed straight through to the photodetector 47. The objective lenses 44 and 45 include a first objective lens 44 and a second objective lens 45 which are arranged to be spaced apart from the actuator 60 by a predetermined interval and have different numerical apertures. The first objective lens 44 preferably has a numerical aperture of 0.6, which is suitable for the case where the CD 10b is employed as the disk. On the other hand, the second objective lens 45 preferably has a numerical aperture of 0.45, which is suitable for the case where the DVD 10a is employed as the disc. The actuator 60 drives the first and second objective lenses 44 and 45 in a radial direction of the disc 10 and a direction perpendicular to the disc 10, that is, in a focus direction. The photodetector 47 receives the light reflected from the disk 10 and transmitted through the beam splitter 43 to detect a focus error signal and a track error signal. This photodetector 47 comprises two or more dividers.

The beam splitter 43 and the photodetector 47 are installed to be transported so that the light emitted from the light source 41 is selectively directed to the first objective lens 44 and the second objective lens 45. do.

Therefore, when the CD 10b is employed as the disc, the beam splitter 43 and the photodetector 47 are provided at the A position indicated by the solid line of the bottom surface of the first objective lens 44, and the light source 41 is disposed on the light source 41 side. The incident light is guided to pass through the first objective lens 44. In the case where the DVD 10b is employed as the disc, the beam splitter 43 and the photodetector 47 are provided at the B position indicated by the dotted line on the bottom surface of the second objective lens 45 to the light source 41 side. The incident light is guided to pass through the second objective lens 45.

In addition, the present invention further comprises a collimating lens 42 for converging the divergent light emitted from the light source 41 on the optical path between the light source 41 and the beam splitter 43 to convert into parallel light. Can be. In addition, it is preferable to further include an astigmatism lens 46 on the optical path between the beam splitter 43 and the photodetector 47.

4 is a layout view showing an optical configuration of a compatible optical pickup device according to another embodiment of the present invention. As shown, in its optical configuration, the light source 41, the beam splitter 53, the first and second objective lenses 44, 45, the actuator 60, and the photodetectors 57, 58 are provided. It includes. The light source 41, the beam splitter 53, the first and second objective lenses 44 and 45, and the actuator 60 are substantially the same as those of the members described with reference to FIG. Since it is the same, detailed description thereof will be omitted.

The photodetector includes a first photodetector 57 and a second photodetector 58, each of which is fixedly disposed at a position corresponding to the first objective lens 44 and the second objective lens 45, respectively. It has that feature. As such, when the beam splitter 53 is provided to the A 'position and the B' position, the traveling path of the light incident from the light source 41 toward the first objective lens 44 or the second objective lens ( 45). In addition, the present invention may further include a collimating lens 42 and an astigmatism lens 56 at each predetermined position on the optical path, as described through one embodiment. That is, the collimating lens 42 is fixedly disposed on an optical path between the light source 41 and the beam splitter 53, and the astigmatism lens 56 is disposed to be movable together with the beam splitter 53. do.

The configuration of the actuator 60 of the compatible optical pickup apparatus according to the embodiments of the present invention described with reference to FIGS. 3 and 4 will be described with reference to FIGS. 5 to 8.

FIG. 5 is a schematic plan view showing an actuator according to the present invention, and FIG. 6 is an enlarged cross-sectional view of part VI of FIG. 5. Here, the y axis represents the radial direction of the disk, the x axis represents the tangential direction of the disk, and the z axis (see FIGS. 7 to 9) represents the focus direction.

As shown, the base 61 conveyed in the radial direction (y-axis direction) of the disk, the holder 63 provided on the base 61, and the first and second objective lenses 44 and 45. It comprises a bobbin 67 for fixing the suspension, a suspension 69 for connecting the bobbin 67 to the holder 63, and magnetic drive means for moving the bobbin 67 by a magnetic force.

Since the base 61, the bobbin 67 and the suspension 69 are substantially the same as or similar to the conventional members described with reference to FIG. 2 in their structure and function, detailed description thereof will be omitted.

The holder 63 is a member for installing the first objective lens 44 and the second objective lens 45 to be spaced apart from each other by a predetermined distance, and is supported by the suspension 69 to have a disk radius on the base 61. Direction and the disc track direction.

The magnetic driving means includes a pair of first magnets 71 and a second magnet 72 provided on the base 61 so as to face each of two sides of the bobbin 67 parallel to the disc radial direction (y-axis direction). And a coil part formed on the outside of the bobbin 67.

Each of the first magnet 71 and the second magnet 72 is fixed to the first outer yoke 73 and the second outer yoke 74 on the base 61.

The coil part is integrally formed on the outside of the bobbin 67 by deposition and etching, and the magnetic layer 81, the first dielectric layer 82, and the first pattern of the bobbin 67 are sequentially stacked on the base 61. The coil 83, the second dielectric layer 84, the second pattern coil 85, and the third dielectric layer 86 are included. The magnetic layer 81 is preferably made of a ferromagnetic material, and is deposited on the side facing each of the first and second magnets 71 and 72 of the bobbin 67. This magnetic layer 81 serves as an inner yoke (37a, 37b in FIG. 2) included in a conventional actuator. The first dielectric layer 82 is a layer formed by vapor deposition to electrically separate the magnetic layer 81 and the first pattern coil 83, and is formed of a material such as SiO.

As illustrated in FIG. 7, the first pattern coil 83 is formed in a spiral shape around the bobbin 67 by deposition and etching to surround the bobbin 67, and the bobbin 67. ) Is driven in the focus direction of the disc. Both ends 83a of the first pattern coil 83 are exposed to the outside so that external power can be applied. The first pattern coil 83 is made of a metal material such as aluminum (Al), copper (Cu), platinum (Pt), silver (Ag), and the like, which have very low electrical resistance.

As shown in FIG. 6, the second dielectric layer 84 is positioned between the first pattern coil 83 and the second pattern coil 85 and is a layer for electrical insulation between two layers. 1 made of the same material as the dielectric layer 82.

The second pattern coils 85 are paired by deposition and etching on portions of the second dielectric layer 84 that face the first magnet 71 and portions that face the second magnet 72. And the bobbin 67 is driven in the disc track direction. The shape of the second pattern coil 85 will be described with reference to FIG. 8. As shown, the pair of second pattern coils 85 facing the first magnet 71 or the second magnet 72 is formed in a spiral coil shape, the rotation direction of the spiral is opposite to each other It is formed. One end of the pair of second pattern coils 85 is exposed to the outside, and the other end 85b is connected to each other by a connecting portion 87 described later formed outside the third dielectric layer 86. . Therefore, when an external power source is applied, current is applied in one direction to the coils located inside the pair of second pattern coils 85. The magnets 71 and 72 disposed as shown by the dotted lines in FIG. 8 face the inner side of the second pattern coil 85. The second pattern coil 85 is substantially made of the same material as the first pattern coil 83.

Referring to FIG. 6, the third dielectric layer 86 may be a layer deposited on the second pattern coil 85 to form a connection portion 87 connecting one end of the second pattern coil 85 to each other. In addition, the second pattern coil 85 is prevented from being damaged. A contact groove 88 is formed in a portion of the third dielectric layer 86 so that the end portion of the second pattern coil 85 is exposed to the outside. An external current is connected to the second pattern coil 85 through the contact groove 88. As shown in FIG. 9, the connection part 87 is preferably connected between the inner ends 85b of the pair of second pattern coils 85 and is not short-circuited with the second pattern coils 85. So as to be positioned on the third dielectric layer 86.

As described above, the optical pickup actuator according to the present invention includes the bobbin 67 by a current applied to the first pattern coil 83 and a mutual electromagnetic force between the first and second magnets 71 and 72. ) Can move in the focus direction, and the bobbin 67 is moved in the radial direction of the disc by the mutual electromagnetic force between the current applied to the second pattern coil 85 and the first and second magnets 71 and 72. Can move.

As described above, the compatible optical pickup apparatus according to the present invention employs two objective lenses suitable for discs having different formats, and installs a beam splitter so as to perform recording / reproducing of information without degrading optical efficiency. Can be. In addition, by providing a coil integrally to the outside of the bobbin of the actuator through deposition and etching, it is possible to significantly reduce the mass of the actuator, it is possible to reduce the load on the transfer of the compatible optical pickup device in the radial direction of the disk. In addition, the size can be reduced by forming the coil in a thin pattern.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible therefrom.

Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the claims.

Claims (7)

A light source; A beam splitter for changing a traveling path of incident light; An objective lens disposed between the light source and the disk to focus incident light on the disk; An actuator on which the objective lens is mounted; In the compatible optical pickup device comprising a; optical detector for detecting information and error signals by receiving light reflected from the disk and through the beam splitter, The objective lens may include a first objective lens disposed spaced apart from the actuator at a predetermined interval and having a different numerical aperture; Including a second objective lens, The actuator includes a base on which the light source, the beam splitter, and the photodetector are located; A bobbin fixed to the objective lens and positioned on the base; A suspension fixed at one end to the base and movably supporting the bobbin; And magnetic drive means for driving the bobbin in a disc track radial direction and a disc focus direction. And the beam splitter is installed to be transported such that light emitted from the light source is selectively directed to the first objective lens and the second objective lens. 2. The apparatus of claim 1, wherein the magnetic drive means comprises: a pair of first and second magnets mounted on the base opposite each of two sides of the bobbin parallel to the disc track radial direction; A magnetic layer deposited on a side facing each of the first and second magnets of the bobbin; A first dielectric layer deposited on the magnetic layer; A first pattern coil which is formed to be wrapped around the bobbin so that the bobbin is driven in a focus direction of the disk; A second dielectric layer deposited on a side of the bobbin facing the first and second magnets on the first pattern coil; A second pattern coil provided at each of a portion facing the first magnet and a portion facing the second magnet on the second dielectric layer to drive the bobbin in the disc track direction; And a third dielectric layer deposited on the second pattern coil. 3. The compatible light as claimed in claim 2, wherein each of the pair of second pattern coils facing the first magnet is exposed to the outside thereof and the other end thereof is connected to each other by a connection portion formed outside the third dielectric layer. Pickup device. 3. The compatible light according to claim 2, wherein each of the pair of second pattern coils facing the second magnet is exposed to the outside and the other end is connected to each other by a connection part formed outside the third dielectric layer. Pickup device. The compatible optical pickup apparatus of claim 1, wherein the first objective lens has a numerical aperture of 0.6 and the second objective lens has a numerical aperture of 0.45. 2. The optical detector of claim 1, wherein the photodetector includes a first photodetector that is reflected from the disk and passes through the first objective lens to receive light through the beam splitter, and the second objective lens is reflected from the disk. And a second photodetector configured to pass through and receive light through the beam splitter. The compatible optical pickup apparatus of claim 1, wherein the photodetector is installed to be transported together with the beam splitter to receive light transmitted through the beam splitter.