JP3905966B2 - Method for adjusting optical head device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical head device applied to an optical disk device that reads information from an optical disk as a recording medium and records information on the optical disk, and in particular, adjusts an emission angle of a light beam emitted from a light source of the optical head device. The present invention relates to an adjustment mechanism and an adjustment method.
[0002]
[Prior art]
The optical disk device includes an optical head device having an objective lens and a photodetector, and reflects light corresponding to information recorded on the optical disk by irradiating a recording medium, that is, a recording surface of the optical disk with a light beam from a semiconductor laser element. It is used to record information on an optical disc while reading out and reading out information.
[0003]
The optical head device described above includes a semiconductor laser element as a light source for generating a light beam, and a reflected light reflected from the recording surface while focusing the light beam emitted from the semiconductor laser element on a recording surface of an optical disk as a recording medium. An objective lens for extracting the beam, and a plurality of photodetectors or photodetectors that detect and photoelectrically convert the reflected light beam extracted by the objective lens and output a reproduction signal corresponding to the information recorded on the optical disc; It is formed by a plurality of optical members or the like constituting an optical path of a light beam between elements.
[0004]
[Problems to be solved by the invention]
Incidentally, a semiconductor laser element used as a light source emits a light beam having an elliptical beam cross section. That is, the light beam from the semiconductor laser element is emitted with a radiation angle of, for example, 25 ° in the major axis direction and with a radiation angle of, for example, 10 ° in the minor axis direction in the beam cross section.
[0005]
In addition, a semiconductor laser element cannot always emit a light beam in a direction perpendicular to the reference surface of the element. That is, the light beam from the semiconductor laser element is emitted with a tolerance of, for example, ± 2 ° in the major axis direction and the minor axis direction in the beam cross section.
[0006]
For this reason, the luminance center of the light beam emitted from the semiconductor laser element may be displaced from the optical axis.
The deviation of the radiation angle with respect to the optical axis, that is, the slight deviation of the luminance center, increases as the optical path from the light source to the recording surface of the optical disc becomes longer. As a result, there arises a problem that it is difficult to accurately read information from the optical disk, and it is difficult to accurately record information on the optical disk.
[0007]
Thus, it has been proposed to arrange a glass plate so as to be inclined with respect to the optical axis in the optical path from the light source to the recording surface of the optical disc, and to correct the deviation of the radiation angle of the light beam. There is a problem in that the number of points increases and the cost increases, and it is necessary to secure a region for arranging the glass plate, which is disadvantageous for downsizing of the apparatus.
[0008]
The present invention can correct the deviation of the radiation angle of the light beam emitted from the light source without increasing the number of components, accurately reproduce the information recorded on the recording medium, and accurately reproduce the information on the recording medium. It is an object of the present invention to provide an optical head device and an optical head device adjustment method capable of recording data.
[0009]
[Means for Solving the Problems]
  The present invention has been made based on the above-described problems.
  The light amount adjustment method of the optical head device according to an aspect of the present invention includes:
  A light source that emits a light beam having an elliptical beam cross section is supported by a support member having a cylindrical surface with a predetermined curvature radius that is convex in the direction in which the light source emits the light beam,
  With respect to the fixing member having a concave cylindrical surface having the same radius of curvature as the convex cylindrical surface of the support member, the concave shape of the fixing member is set so that the reference surface of the light source is perpendicular to the optical axis. A cylindrical surface of the support member is brought into contact with the cylindrical surface;
  When the luminance center of the light beam emitted from the light source has a θ shift angle with respect to the optical axis, the convex cylindrical surface of the support member is aligned with the concave cylindrical surface of the fixing member. And adjusting the radiation angle in the minor axis direction in the beam cross section of the light beam emitted from the light source, by rotating the support member by θ / 2.
  Fixing the support member to the fixing member in a state where the luminance center of the light beam emitted from the light source coincides with the optical axis;
  It is characterized by that.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the optical head device according to the present invention will be described below in detail with reference to the drawings.
As shown in FIG. 1, an optical disc apparatus 100 includes an actuator 4 that is movable in a direction parallel to a recording surface (not shown) of an optical disc D as a recording medium and orthogonal to a track (not shown) provided on the recording surface. The optical head device 2 includes a laser beam transmitting / receiving unit 6 that transmits a laser beam having a predetermined wavelength toward the actuator 4 and receives the laser beam returned from the actuator 4.
[0019]
The actuator 4 is moved in a direction perpendicular to a track (not shown) on a recording surface (not shown) of the optical disk D, that is, a radial direction of the optical disk D, based on a drive signal from the control unit 8.
[0020]
Based on the drive signal from the control unit 8, the laser beam transmitting / receiving unit 6 emits a recording laser beam at the time of writing or recording information, and a reproducing laser beam at the time of reading or reproducing information.
[0021]
The control unit 8 supplies a predetermined control signal to the control unit 8 and transmits / receives a laser beam based on a read or write command (command) from an external device (not shown) input via the signal processing unit 10. The information signal received and photoelectrically converted by the unit 6 is decoded and output to an external device as a reproduction signal.
[0022]
The actuator 4 forms an image of a recording or reproducing laser beam from a light source (to be described later) of the laser beam transmitting / receiving unit 6 at a predetermined position on a recording surface (not shown) of the optical disc D, and on the recording surface of the optical disc D. The objective lens 12 as a condensing means for extracting the reflected laser beam Lr reflected, the direction in which the objective lens 12 is orthogonal to the recording surface of the optical disc D, and a track (information is recorded as information recorded on the recording surface). In a recordable optical disk, an area in which no information is recorded, a pickup 14 that holds the pickup 14 movably along the recording surface in a direction crossing the guide groove or groove), and the optical disk D along the pair of guide rails 16 are arranged. The carriage 18 is supported so as to be movable in the radial direction.
[0023]
As shown in FIG. 2, the pickup 14 can be rotated about a center axis 14 b extending from a base 14 a placed at a predetermined position on the carriage 18 in a direction perpendicular to the recording surface of the optical disc D. The objective lens 12 is held on a lens holding surface 14d provided at one end of the lens holder 14c. Note that either one of the pickup 14 and the carriage 18 is provided with a mirror 20 for guiding the laser beam Lf from the laser beam sending / receiving unit 6 toward the objective lens 12.
[0024]
At a predetermined position on the outer peripheral surface of the lens holder 14c, a focusing coil 14e that generates thrust for moving the objective lens 12 (lens holder 14c) in a direction orthogonal to the recording surface of the optical disc D, that is, along the central axis 14b, A tracking coil 14f for generating a thrust for moving the objective lens 12 (lens holder 14c) in a direction crossing the track on the recording surface of the optical disc D is provided along the curved surface of the outer peripheral surface.
[0025]
In a region surrounding the outer peripheral surface of the lens holder 14c around the central axis 14b, two sets of fixed magnets 14g and 14h for providing a magnetic field in a predetermined direction toward the coils 14e and 14f on the outer peripheral surface of the lens holder 14c, A yoke 14i that holds the fixed magnets 14g and 14h and cooperates with each magnet to form a magnetic circuit is provided. The yoke 14i is divided or arranged in an annular shape along or in the vicinity of a circumference set to an approximately equal radius from the central axis 14b.
[0026]
As shown in FIG. 3, the laser beam transmitting / receiving unit 6 is disposed at a predetermined position in the housing 6a and the housing 6a, and emits a linearly polarized light beam whose vibration direction is substantially aligned in one direction. 30, a light beam which is disposed at a predetermined position in the housing 6 a, transmits a light beam from the light source 30 toward the actuator 4, and reflects a reflected light beam returned from the recording surface of the optical disk D toward the optical disk D. A polarizing beam splitter 32 that is separated from the collimating lens 34, which is disposed at a predetermined position in the housing 6a, is disposed between the polarizing beam splitter 32 and the mirror 20, and collimates the light beam toward the mirror 20 of the actuator 4. 6a is arranged at a predetermined position, and the direction of polarization of the light beam that has passed through the collimating lens 34 is linear. Has an elliptical correction prism 38 that generally correct circular aspect ratio of the light beam passing through the retarder (lambda / 4 plate) 36 and lambda / 4 plate 36, which converts the light into circularly polarized light.
[0027]
Further, the laser beam sending / receiving unit 6 is reflected from the recording surface of the optical disc D, and the reflected laser beam Lr returned via the actuator 4 is separated from the laser beam Lf toward the mirror 20 by the polarization beam splitter 32. A beam splitter (half mirror) 40 that further separates the reflected laser beam Lr into two laser beams, and each of the two laser beams divided by the half mirror 40 is detected and photoelectrically converted to correspond to the intensity of each laser beam. The first photo detector 42 and the second photo detector 46 are provided as photoelectric conversion means for converting into an electric signal.
[0028]
A hologram plate (diffraction element) 48 that gives a predetermined optical characteristic for detecting a focus shift to one of the laser beams divided by the half mirror 40 is provided between the second photodetector 46 and the half mirror 40. Is arranged.
[0029]
The light source 30 is a semiconductor laser element that emits a laser beam Lf having a wavelength of, for example, 650 nm (nanometers), and the direction of linear polarization of the emitted laser beam Lf is reflected by a polarization plane (not shown) of the polarization beam splitter 32. It is fixed to be in the direction. The laser beam emitted from the semiconductor laser element 30 has a substantially elliptical beam cross-sectional shape. In other words, the semiconductor laser element 30 emits a laser beam whose beam cross-sectional length in one axial direction is longer than that in the other axial direction.
[0030]
The polarization beam splitter 32 has a polarization plane (beam split plane) (not shown) in which the direction of polarization is set to be orthogonal to the direction of linear polarization of the laser beam Lf emitted from the semiconductor laser element 30. And the reflected laser beam Lr reflected by the optical disk D is allowed to pass.
[0031]
The λ / 4 plate 36 converts the direction of polarization of the laser beam Lf reflected by the polarization beam splitter 32 from linearly polarized light to circularly polarized light, and changes the direction of polarization of the reflected laser beam Lr reflected by the optical disk D to circularly polarized light. To again convert to linearly polarized light. At this time, a 90 ° phase difference is caused by the λ / 4 plate 36 between the polarization direction of the laser beam Lf directed from the polarization beam splitter 32 toward the optical disc D and the polarization direction of Lr returned from the optical disc D. Given. Thereby, Lr reflected by the optical disk D passes through the polarization plane of the polarization beam splitter 32 and is directed to the half mirror 40.
[0032]
The surface of the ellipse correction prism 38 on the side of the polarization beam splitter 32 returns a part of the laser beam Lf from the semiconductor laser element 30 toward the optical disc D to the polarization beam splitter 32 in relation to APC (auto power control) described later. Therefore, the reflection point (reflection center) of the laser beam Lf on the optical axis O, that is, the polarization beam splitter 32, defined between the center of the laser beam Lf emitted from the semiconductor laser element 30 and the center of the objective lens 12, and the mirror. The axis 20 is inclined at a predetermined angle with respect to the axis connecting the reflection point (reflection center). The incident surface 38a of the ellipse correction prism 38 is formed as a mirror surface that reflects approximately 5 to 50% of the laser beam Lf incident from the semiconductor laser element 30 side.
[0033]
The first photodetector 42 is used for detecting a track shift and has a light receiving region divided into four.
The first photodetector 42 is reflected by the incident surface 38a of the ellipse correction prism 38 independently of the four-divided photodetector, and has a short optical path for a short time compared to the reflected laser beam Lr from the recording surface of the optical disc D. A monitor photo detector 44 that receives and photoelectrically converts the laser beam (Lf) for power control returned in step 1 is integrated.
[0034]
The monitor photodetector 44 is a light intensity of the laser beam (Lf) used for auto power control (hereinafter referred to as APC) for keeping the light intensity of the laser beam Lf emitted from the semiconductor laser element 30 constant. The output current corresponding to the fluctuation of the light intensity is output.
[0035]
The second photodetector 46 is used for detection of a focus shift signal, which will be described later, for matching the focusing between the objective lens 12 and the recording surface of the optical disc D. The second photodetector 46 has a light receiving region divided into four parts, receives a laser beam divided into a plurality of beams by a hologram plate 48 having a hologram diffraction pattern, and corresponds to each light receiving region. A large current is output.
[0036]
The control unit 8 is connected to the CPU 50 as the main control device, the read-only memory (read only memory, hereinafter referred to as ROM) 52 in which initial data for operating the CPU 50 is stored, not shown. A random access memory (hereinafter referred to as RAM) 54 that holds information to be recorded supplied from an external device or data read from the optical disc D, and data input to and output from the RAM 54 are temporarily stored. A buffer memory 56 is provided.
[0037]
The CPU 50 supplies a predetermined drive current to the semiconductor laser element 30 to output a laser beam Lf having a predetermined light intensity, and the semiconductor laser element 30 corresponding to the information to be recorded stored in the RAM 54. A recording laser beam generating circuit 64 for changing the intensity of the laser beam Lf emitted from the laser beam Lf is connected. The recording laser beam generating circuit 64 emits a reproducing laser beam having a constant intensity of about 1/5 of the recording laser beam when reading information from the optical disc D.
[0038]
Further, the CPU 50 is connected to the monitor photodetector 44, and the intensity of the laser beam Lf emitted from the semiconductor laser element 30 is constant based on the intensity of the laser beam (Lf) reflected by the incident surface 38a of the ellipse correction prism 38. An APC (auto power control) circuit 66 for defining a control amount for maintaining the power is connected. Needless to say, the output of the APC circuit 66 is fed back to the laser drive circuit 62.
[0039]
The CPU 50 is also connected to the first photo detector 42 and receives the reflected laser beam Lr reflected by the optical disk D and receives the reflected laser beam Lr and photoelectrically converts the lens holder 14c based on the amount of track deviation obtained from the current value. A track control circuit 70 for setting a current value to be supplied to the tracking coil 14f is connected.
[0040]
The CPU 50 is further connected to the second photo detector 46 and receives the reflected laser beam Lr reflected by the optical disc D, and the objective lens 12, that is, based on the defocus amount obtained from the current value obtained by photoelectric conversion. A focus control circuit 74 that regulates the magnitude of the drive current to the focus coil 14e for controlling the position of the lens holder 14c is connected.
[0041]
By the way, the semiconductor laser element 30 as the light source is attached to the housing 6a of the laser beam transmitting / receiving unit 6 via the adjusting mechanism 100 as the adjusting means. The adjustment mechanism 100 includes a support member 102 to which the semiconductor laser element 100 is attached, and a fixing member 104 that is fixed to the housing 6a side and receives the support member 102.
[0042]
In the example shown in FIG. 3, the semiconductor laser element 30 forms a beam cross section in the XY plane and emits a laser beam in the Z-axis direction. The laser beam emitted from the semiconductor laser element 30 is X It is assumed that the shape is an ellipse having the major axis as the axial direction and the minor axis as the Y-axis direction. That is, the radiation angle in the X-axis direction of the laser beam emitted from the semiconductor laser element 30 is, for example, 25 °, and the radiation angle in the Y-axis direction is, for example, 10 °.
[0043]
In such a semiconductor laser element 30, it is not always possible to emit a light beam in a direction perpendicular to the reference plane of the element. That is, the laser beam from the semiconductor laser element is emitted with a tolerance of, for example, ± 2 ° in the major axis direction and the minor axis direction in the beam cross section. For this reason, the luminance center of the laser beam emitted from the semiconductor laser element may deviate from the optical axis parallel to the Z axis.
[0044]
Thus, when there is a tolerance of ± 2 ° in the X-axis direction and the Y-axis direction, the radiation angle in the short-axis direction, that is, the Y-axis direction in the beam cross section is smaller than the long-axis direction, that is, the X-axis direction. In addition, the deviation of the radiation angle in the Y-axis direction becomes large.
[0045]
For this reason, the adjustment mechanism 100 applied to the semiconductor laser element 30 adjusts the radiation angle in the minor axis direction, that is, the Y-axis direction in this embodiment, in the beam cross section of the laser beam emitted by the semiconductor laser element 30. . That is, the adjustment mechanism 100 is formed to be rotatable in the YZ plane, and can correct a deviation in the Y-axis direction with respect to the optical axis, that is, the Z-axis.
[0046]
FIG. 4 is a perspective view in which the support member 102 and the fixing member 104 constituting the adjustment mechanism 100 are exploded in the Z-axis direction.
As shown in FIG. 4, the support member 102 has a cylindrical surface 102a that is convex in the Z-axis direction. The cross-sectional shape of the cylindrical surface 102a in the YZ plane is an arc shape, and the axis that defines the cylindrical surface 102a is parallel to the X-axis direction. That is, the center of curvature C of the cylindrical surface 102a is located on the axis. The radius of curvature of the cylindrical surface 102a, that is, the distance r1 from the center of curvature C on the axis to the cylindrical surface 102a is, for example, 10 mm.
[0047]
The support member 102 has a circular opening 102b penetrating the cylindrical surface 102a in the Z-axis direction, and the semiconductor laser element 30 is attached to the opening 102b. At this time, the semiconductor laser element 30 is loaded in the opening 102b so as to emit a laser beam toward the convex cylindrical surface. The semiconductor laser element 30 is attached to the support member 102 so that the major axis direction coincides with the X-axis direction in the beam cross section of the emitted laser beam.
[0048]
By rotating the support member 102 having such a structure around the axis, the semiconductor laser element 30 can be substantially rotated and moved along the minor axis direction, that is, the Y-axis direction in the beam cross section. It becomes possible to adjust the radiation angle in the minor axis direction in the beam cross section of the laser beam.
[0049]
The fixing member 104 that receives the support member 102 is fixed to the housing 6 a of the laser beam transmitting / receiving unit 6. The fixing member 104 has a cylindrical surface 104a that is concave in the Z-axis direction. The cross-sectional shape of the cylindrical surface 104a in the YZ plane is an arc shape, and the axis that defines the cylindrical surface 104a is parallel to the X-axis direction. That is, the center of curvature C of the cylindrical surface 104a is located on the axis. The radius of curvature of the cylindrical surface 104a, that is, the distance from the center of curvature C on the axis to the cylindrical surface 104a is r1 which is the same as the radius of curvature of the cylindrical surface 102a of the support member 102, and is 10 mm in this embodiment.
[0050]
The fixing member 104 has a circular opening 104b that penetrates the cylindrical surface 104a in the Z-axis direction. The opening 104 b is provided to guide a laser beam emitted from the semiconductor laser element 30 attached to the support member 102 to a subsequent optical system such as the beam splitter 32, and is formed in the support member 102. It has a larger diameter than the portion 102b.
[0051]
The convex cylindrical surface 102a of the supporting member 102 is brought into contact with the concave cylindrical surface 104a of the fixing member 104 having such a structure, and the cylindrical surface 102a is slid along the cylindrical surface 104a, whereby the supporting member 102 is cylindrical. It can be rotated about the axis of the surface 102a. As a result, the semiconductor laser element 30 can be substantially rotated and moved along the minor axis direction in the beam section, that is, the Y axis direction, and the radiation angle of the emitted laser beam in the minor axis direction is adjusted. It becomes possible to do. Accordingly, it is possible to correct the radiation angle in the minor axis direction of the laser beam emitted from the semiconductor laser element 30, and to make the luminance center of the laser beam parallel to the optical axis, that is, the Z axis in the minor axis direction. Become.
[0052]
FIGS. 5A and 5B are views showing a state in which the cylindrical surface of the support member is in contact with the cylindrical surface of the fixing member in the adjustment mechanism, and FIG. 5A is a cross-section in the YZ plane. (B) is a rear view in the XY plane.
[0053]
As shown in FIG. 5B, the fixing member 104 of the adjustment mechanism 100 is fixed to a housing of a laser beam transmitting / receiving unit (not shown) with a screw 106. At this time, the concave cylindrical surface that receives the support member 102 is released from the housing.
[0054]
Then, as shown in FIG. 5A, the concave cylindrical surface of the fixing member 104 so that the reference surface of the semiconductor laser element 30 attached to the support member 102 is perpendicular to the optical axis O. The cylindrical surface 102a of the support member 102 is brought into contact with 104a.
[0055]
At this time, it is assumed that the luminance center of the laser beam emitted from the semiconductor laser element 30 has a deviation angle of θ with respect to the optical axis O as shown in FIG.
In this case, as shown in FIG. 6A, the convex cylinder of the support member 102 is centered on the center of curvature C of the convex cylindrical surface 102a of the support member 102 and the concave cylindrical surface 104a of the fixing member 104. The surface 102a is slid along the concave cylindrical surface 104a of the fixing member 104, and the support member 102 is rotated by θ / 2, thereby adjusting the radiation angle of the laser beam with respect to the short axis component in the beam cross section. Thus, the center of luminance of the laser beam and the optical axis O can be matched.
[0056]
The optical axis adjustment of such a light source is performed, for example, by radiating a laser beam from the semiconductor laser element 30 and imaging the emitted laser beam with a CCD camera, so that the luminance center coincides with the optical axis O. This is accomplished by moving 102.
[0057]
Then, the support member 102 is bonded to the fixing member 104 in a state where the optical axis O is adjusted as described above, thereby being fixed as shown in FIGS. 6A and 6B.
[0058]
Further, as shown in FIGS. 7A and 7B, the support member 102 may be fixed by being screwed to the fixing member 104 in a state where the optical axis O is adjusted. That is, a pair of screw holes 104 c are formed in the fixing member 104 in advance. Further, a through hole 102c larger than the diameter of the screw hole 104c is formed in advance at a position substantially corresponding to the position of the screw hole 104c of the fixing member 104 in the support member 102. Then, the support member 102 is fixed to the fixing member 104 by screwing it into the screw hole 104c of the fixing member 104 through the through hole 102c of the supporting member 102 with the optical axis adjusted.
[0059]
In the embodiment described above, the optical head device supports the light source 30 and has a single curvature as shown in FIG. 4 in order to mount the light source 30 on the housing 6a of the laser beam transmitting / receiving unit 6. A support member 102 having a convex cylindrical surface 102a with a radius r1, and a fixing member 104 attached to the housing 6a and having a concave cylindrical surface 104a with the same radius of curvature as the curvature radius r1 of the support member 102. I have.
[0060]
The light source 30 emits an elliptical laser beam in the beam cross section, and the light source 30 is supported so that the major axis direction in the beam cross section and the axial direction defining the convex cylindrical surface 102a are substantially parallel. It is attached to the member 102. Then, the cylindrical surface 102a of the support member 102 to which the light source 30 is attached is brought into contact with the cylindrical surface 104a of the fixing member 104, and the support member 102 is rotated about the axis line as a central axis. It is possible to adjust the radiation angle in the minor axis direction in the beam cross section.
[0061]
In other words, the mechanism for mounting the light source 30 on the housing 6a can be applied as the adjustment mechanism 100 for adjusting the radiation angle in the short axis direction of the laser beam emitted from the light source 30.
[0062]
For this reason, it is possible to correct the deviation of the emission angle of the laser beam emitted from the light source without increasing the number of components, and the luminance center of the laser beam can be made to substantially coincide with the optical axis.
[0063]
This makes it possible to optimize the shape of the beam cross section toward the optical disc in the laser beam emitted from the light source, accurately reproduce information recorded on the optical disc, and accurately record information on the optical disc. It becomes possible to do.
[0064]
In the embodiment described above, as shown in FIG. 4, the support member 102 is formed to have a single cylindrical surface 102a having a single radius of curvature r1, but the support member 102 is fixed to the fixing member. If the concave cylindrical surface 104a of 104 can be slidably provided, it is not necessary to form only a single cylindrical surface.
[0065]
That is, as shown in FIG. 8, the support member 120 includes a first cylindrical surface 120a having a first curvature radius r1 that contacts the concave cylindrical surface 104a of the fixing member 104, and a second smaller than the first curvature radius r1. And a second cylindrical surface 120c having a radius of curvature r2. The second cylindrical surface 120c has the same center of curvature C as the first cylindrical surface 120a.
[0066]
The second cylindrical surface 120c forms a predetermined gap D from the cylindrical surface 104a when the first cylindrical surface 120a contacts the concave cylindrical surface 104a of the fixing member 104, as shown in FIG. , Provided.
[0067]
The gap D is desirably 0.3 mm or less in order to dissipate the heat generated by the light source 30 to the fixing member 104 via the support member 120.
Note that the second cylindrical surface 120c is not necessarily a cylindrical surface. That is, when the first cylindrical surface 120a of the support member 120 is in contact with the concave cylindrical surface 104a of the fixing member 104, it may be a flat surface as long as the predetermined gap D can be formed from the cylindrical surface 104a.
[0068]
With such a structure, the contact area between the first cylindrical surface 120a of the support member 120 and the concave cylindrical surface 104a of the fixing member 104 can be reduced. This facilitates the processing of the first cylindrical surface 120a of the support member 120 and facilitates the processing of the support member 120 itself.
[0069]
Even when the support member 120 having such a structure is applied, the deviation of the radiation angle of the laser beam emitted from the light source is corrected without increasing the number of components, as in the above-described embodiment. It becomes possible to make the luminance center of the laser beam substantially coincide with the optical axis.
[0070]
This makes it possible to optimize the shape of the beam cross section toward the optical disc in the laser beam emitted from the light source, accurately reproduce information recorded on the optical disc, and accurately record information on the optical disc. It becomes possible to do.
[0071]
Note that the radii of curvature of the cylindrical surfaces of the support member and the fixing member are determined depending on the adjustment accuracy. That is, by increasing the radius of curvature, it is possible to adjust the more accurate deviation angle.
[0072]
【The invention's effect】
As described above, according to the present invention, the deviation of the radiation angle of the light beam emitted from the light source can be corrected without increasing the number of parts, and the information recorded on the recording medium can be accurately reproduced, An optical head device capable of accurately recording information on a recording medium and a method for adjusting the optical head device can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an optical disk apparatus in which an optical head device of the present invention is used.
FIG. 2 is a schematic diagram for explaining an actuator pickup of the optical head device shown in FIG. 1;
FIG. 3 is a schematic diagram for explaining a laser beam sending / receiving unit of the optical disc apparatus shown in FIG. 1;
FIG. 4 is a perspective view schematically showing a structure of a mechanism for adjusting a radiation angle of a laser beam emitted from a light source applied to an optical head device.
5A is a cross-sectional view showing a state in which a support member is in contact with the fixing member of the adjustment mechanism shown in FIG. 4, and FIG. 5B is a cross-sectional view of FIG. It is a rear view of the adjustment mechanism in the state shown in FIG.
6A is a cross-sectional view showing a state in which the radiation angle is adjusted in the adjustment mechanism shown in FIG. 5A, and FIG. 6B is a cross-sectional view of FIG. It is a rear view of the adjustment mechanism in the state shown in FIG.
7A is a cross-sectional view showing a state in which the fixing member and the support member are fixed in a state where the radiation angle is adjusted by the adjustment mechanism, and FIG. 7B is a cross-sectional view of FIG. It is a rear view of the adjustment mechanism in the state shown to (a).
FIG. 8 is a perspective view schematically showing the structure of another support member that constitutes the adjustment mechanism shown in FIG. 4;
FIG. 9 is a cross-sectional view showing a state in which the radiation angle is adjusted when the support member shown in FIG. 8 is applied as an adjustment mechanism.
[Explanation of symbols]
2 ... Optical disk device
4 ... Actuator
6 ... Laser beam sending / receiving unit
6a ... Housing
12 ... Objective lens
14 ... Pickup
16 ... guide rail
18 Carriage
20 ... mirror
30 ... Semiconductor laser element (light source)
100: Adjustment mechanism
102: Support member
102a ... Convex cylindrical surface
104: Fixing member
104a ... concave cylindrical surface
120 ... Supporting member
120a ... 1st cylindrical surface
120c ... 2nd cylindrical surface

Claims (1)

A light source that emits a light beam having an elliptical beam cross section is supported by a support member having a cylindrical surface with a predetermined curvature radius that is convex in the direction in which the light source emits the light beam,
With respect to the fixing member having a concave cylindrical surface having the same radius of curvature as the convex cylindrical surface of the support member, the concave shape of the fixing member is set so that the reference surface of the light source is perpendicular to the optical axis. A cylindrical surface of the support member is brought into contact with the cylindrical surface;
When the luminance center of the light beam emitted from the light source has a θ shift angle with respect to the optical axis, the convex cylindrical surface of the support member is aligned with the concave cylindrical surface of the fixing member. And adjusting the radiation angle in the minor axis direction in the beam cross section of the light beam emitted from the light source, by rotating the support member by θ / 2.
Fixing the support member to the fixing member in a state where the luminance center of the light beam emitted from the light source coincides with the optical axis;
A method of adjusting an optical head device.

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