JP2007012184A - Optical head and optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical head and an optical pickup device having a structure capable of easily adjusting an optical axis without changing the position of a light emission point. <P>SOLUTION: The optical head 1 is composed of a laser holder 21 holding a laser diode 11 and a holder receiving stage 31 holding the laser holder 21. The laser holder 21 is provided with an abutment part 23 constituted by an arc surface having the central axis C passing through the light emission point EP and perpendicular to the optical axis P. The holder receiving stage 31 is provided with a planar receive face 32 which is perpendicular to the optical axis P and on which the abutment part 23 abuts. Accordingly, because the light emission point EP is on the central axis C of the arc surface constituting the abutment part 23, even when the laser holder 21 is inclined for the optical axis adjustment, the position of the light emission point EP is not changed. Thus, the optical axis adjustment is easily performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical head having a structure for adjusting an optical axis of a laser beam and an optical pickup device using such an optical head.

  An optical pickup device irradiates an information recording medium with laser light emitted from a laser diode through a collimator lens, a beam shaping prism, an objective lens, and the like, and reflects light reflected by the surface of the information recording medium with a photodetector. It is read as a signal.

  The laser light is converted into parallel light by a collimator lens, shaped into a circular beam by a beam shaping prism, focused by an objective lens through a beam splitter, and irradiated onto an information recording medium. The reflected light reflected by the information recording medium is reflected by the beam splitter through the objective lens in the right angle direction and received by the photodetector. In this way, the optical components are arranged with their optical axes aligned so that the laser light passes through a certain optical path.

  Laser diodes that emit laser light are arranged so that the optical axis of the laser light coincides with the optical axis of the optical pickup device. However, since laser diodes vary in optical axis depending on the individual product, It is necessary to adjust the mounting angle and position of the laser diode.

  Therefore, the optical head to which the laser diode is fixed is provided with a structure for adjusting the optical axis of the laser light.

  A structure related to optical axis adjustment of an optical head of a conventional optical pickup device will be described with reference to FIGS.

  FIG. 9 is a schematic view of an optical head of Conventional Example 1. FIG. 10 is a schematic view of an optical head of Conventional Example 2. FIG. 11 is a schematic diagram of an optical head of Conventional Example 3.

  For example, the optical head 101 according to the conventional example 1 includes a laser diode 111, a holder 121 that holds the laser diode 111, and an adapter 131 that fixes the holder 121 to the housing 141. The holder 121 is connected to the adapter 131 by a holder fixing screw 171. The adapter 131 is fixed to the housing 141 by an adapter fixing screw 181. The tilt of the laser diode 111 is adjusted by inserting / removing the holder fixing screw 171 and tilting the holder 121, and the adapter 131 is moved together with the holder 121 by adjusting the adapter fixing screw 181 so that the position of the laser diode 111 is adjusted. It is the structure adjusted (refer patent document 1).

  The optical head 201 of Conventional Example 2 includes a laser diode 211, an adjustment plate 221 that adjusts the inclination of the laser diode 211, and a fixed plate 291 that fixes the laser diode 211 to the adjustment plate 221. The adjustment plate 221 has a U-shaped flat plate, one flat portion is fixed to the housing 231, an opening 223 is provided at the substantially central portion of both flat portions, and the laser diode 211 is fitted therein. Is fixed. The U-shaped adjusting plate 221 is provided with an adjusting screw 271 at the end, and by adjusting the U-shaped parallelism by widening or narrowing the interval of the U-shape by inserting and removing the adjusting screw 271. The inclination of the laser diode 211 can be adjusted. Further, since the diameter of the opening 223 is slightly larger than the diameter of the laser diode 211, the position of the laser diode 211 can be adjusted (see Patent Document 2).

The optical head 301 of Conventional Example 3 includes a laser diode 311, a holding holder 381 that holds the laser diode 311, and a fixed seat 321 that holds the holding holder 381. The holding holder 381 is provided with an opening 383 for fixing the laser diode 311 at the center thereof. The laser diode 311 is fixed, and the outer edge thereof is spherically processed to form a spherical portion 385. On the other hand, the fixed seat 321 that holds the holding holder 381 is provided with a fixed seat opening 323 for holding the holding holder 381 at the center thereof, and the fixed seat opening 323 has a spherical portion 385 of the holding holder 381. Is provided with a spherical surface receiving portion 325 that is processed into a spherical surface that comes into contact with. As a result, the optical head 301 is rotated while the spherical surface portion 385 and the spherical surface receiving portion 325 are in sliding contact with each other, so that the inclination is adjusted. Further, since the light emitting point of the laser diode 311 is arranged at the center of the spherical surface, the position of the light emitting point does not change even if the inclination is changed. (See Patent Document 3).
JP-A-2-294949 Japanese Patent No. 2835778 JP-A-5-81693

  However, in any of the conventional examples, the optical axis adjustment is troublesome in all cases, and time is required for the adjustment time.

  In Conventional Example 1, when adjusting the optical axis, it is necessary to put in and take out the screws 171 and 181, which takes time. The laser diode 111 is tilted by inserting and removing the holder fixing screw 171 and tilting the holder 121. At this time, the position of the light emitting point of the laser diode 111 changes. That is, since the holder 121 is tilted with one holder fixing screw 171 as a fulcrum, the light emitting point of the laser diode 111 fixed to the holder 121 moves around the fulcrum. Therefore, even when only the inclination of the laser beam is to be adjusted, it is necessary to adjust the position at the same time.

  In the conventional example 2, when adjusting the inclination of the laser diode 211, there is a merit that it can be adjusted with one adjustment screw 271, but the adjustment plate 221 has an end opposite to the position where the adjustment screw 271 is located as a fulcrum. Since the tilting is performed, there is a problem that the position of the light emitting point of the laser diode 211 fixed to the adjustment plate 221 changes. Further, when the position is adjusted, it is necessary to take out the screws of the fixing plate 291 and take time.

  In Conventional Example 3, although the position of the light emitting point of the laser diode 311 does not change, when adjusting the position of the laser diode 311, it is necessary to adjust the position by releasing the fastening with the housing to which the fixed seat 321 is fixed. There was and it took time.

  The present invention has been made in view of such a situation, and an optical head and an optical pickup device capable of easily adjusting the optical axis without changing the position of the light emitting point with respect to the optical axis direction of the optical head. Is to provide.

  An optical head according to the present invention includes a laser holder for holding a laser diode and a holder cradle for holding the laser holder, and irradiates an information recording medium with laser light from the laser diode to record / reproduce information. In the optical head, the laser holder is a frame that fixes the laser diode, and has a contact portion protruding from the bottom of the frame, and the holder cradle includes the contact portion. A receiving surface for abutting and supporting and a through-hole for allowing the laser beam to pass therethrough, the receiving surface being a plane substantially perpendicular to the optical axis of the optical head, and the abutting portion defines a light emitting point of the laser diode. As a circular arc surface having a central axis perpendicular to the optical axis.

  With this configuration, even if the laser holder is tilted to adjust the optical axis of the laser beam, the laser holder rotates with respect to the central axis, so the position of the light emitting point does not change in the optical axis direction of the optical head. . Therefore, conventionally, when the angle of the laser holder is changed, the position of the light emitting point has changed in the optical axis direction of the optical head. Therefore, it has been necessary to adjust the position of the light emitting point each time the angle is changed. Can be simplified.

  Further, since the receiving surface is a plane substantially perpendicular to the optical axis, the position of the light emitting point does not change in the optical axis direction of the optical head even if the contact portion of the laser holder is moved in contact with the receiving surface. That is, even if the angle adjustment and the position adjustment are performed, the position of the light emitting point does not change with respect to the optical axis direction of the optical head, so that the angle adjustment and the position adjustment can be performed at the same time. be able to.

  Further, since the laser holder is not configured to be fixed to the holder cradle by a connecting member such as a screw, the number of components can be reduced. Further, when adjusting the angle or adjusting the position, it is not necessary to put in and out screws and the like, and the adjustment work time is shortened.

  Further, since the holder cradle has a flat receiving surface, it can be easily processed with high accuracy, and the manufacturing cost can be kept low.

  Further, the optical head according to the present invention is characterized in that a pair of the contact portions are formed at two opposing positions of the frame body.

  With this configuration, the laser holder is abutted against the receiving surface by the abutting portions that are arranged in parallel at two opposing positions, so that the laser holder is stably supported by the holder cradle.

  In the optical head according to the present invention, the laser holder has a top portion corresponding to the abutting portion at a head portion facing the bottom portion, and the abutting portion includes the receiving surface on the receiving surface. It has a pressing means which presses the top of the head in the direction which presses.

  With this configuration, the laser holder is pressed and supported by the holder cradle by the pressing means, so that the attitude of the laser holder is always kept constant, the laser holder can be easily adjusted in position and angle, and the work after the adjustment can be performed. It is easy to do. That is, in the case where the posture of the laser holder is not maintained, the adjusted state needs to be temporarily fixed with a jig or the like, but such temporary fixing is not necessary.

  In addition, since the laser holder is not pressed from a direction other than the optical axis direction of the optical head (direction perpendicular to the optical axis of the optical head) by the pressing means, it can be easily moved in the direction perpendicular to the optical axis, Further, the laser holder can be easily tilted.

  Further, in the optical head according to the present invention, the top is a protrusion made of an arc surface having the central axis, and the pressing means is a pressing member having a flat pressing surface perpendicular to the optical axis. It is characterized by being configured to press the top of the head.

  With this configuration, the abutting portion and the top of the head are configured by an arc surface having a central axis that passes through the light emitting point and is perpendicular to the optical axis. Thus, the distance between the contact point where the contact portion contacts the receiving surface and the central axis, and the distance between the pressing contact where the top portion contacts the pressing surface and the central axis do not change. That is, since the distance between the contact point and the pressing contact is constant, the force with which the pressing member presses the top of the head does not change, and the laser holder is pressed and supported in a stable state at all times.

  The abutting portion and the top of the head are made of arc surfaces having a central axis that passes through the light emitting point and is perpendicular to the optical axis, and the receiving surface and the pressing surface are planes perpendicular to the optical axis and parallel to each other. Therefore, even if the laser holder is tilted and rotated with respect to the central axis, the pressing direction of the pressing surface is always the optical axis direction, so that the laser holder is pressed and supported in a stable posture.

  The optical head according to the present invention is characterized in that a distance from the central axis to the arc surface of the contact portion is smaller than a distance from the central axis to the arc surface of the top of the head.

  With this configuration, by reducing the radius of the contact portion formed by the circular arc surface, variation in radius can be reduced, and variation in the distance from the light emitting point to the receiving surface can be suppressed.

  That is, when the laser holder is tilted, the contact point between the contact portion and the receiving surface changes, so that when the radius of the contact portion formed by the arc surface varies, the distance from the light emitting point to the receiving surface changes. However, such a distance variation can be suppressed.

  Further, the optical head according to the present invention is characterized in that the contact portion has a tapered surface that continuously circumscribes the arc surface.

  With this configuration, the gap between the laser holder and the holder cradle formed by providing the contact portion on the laser holder is reduced, so that heat generated from the laser diode is transmitted to the holder cradle via the laser holder, The heat dissipation of the head can be improved.

  An optical head according to the present invention includes a laser holder that holds a laser diode and a holder cradle that holds the laser holder, and records information by irradiating an information recording medium with laser light from the laser diode. In the optical head that performs the reproduction, the laser holder is a frame that fixes the laser diode, and a bottom portion of the frame is provided with a contact portion that projects a ridge line portion intersecting two planes, The holder cradle has a receiving surface for abutting and supporting the abutting portion and a through hole for allowing the laser beam to pass therethrough, and the receiving surface is a plane substantially perpendicular to the optical axis of the optical head, and the ridgeline The unit is characterized by being aligned with a straight line passing through the light emitting point of the laser diode and perpendicular to the optical axis.

  With this configuration, the ridge line part is in contact with the receiving surface through the light emitting point, and even if the laser holder is tilted to adjust the optical axis of the laser beam, the laser holder can rotate with respect to the ridge line part. Therefore, the position of the light emitting point does not change in the optical axis direction. Therefore, in the past, when the tilt of the laser holder was changed, the position of the light emitting point changed in the optical axis direction. Therefore, it was necessary to adjust the position of the light emitting point each time the tilt was changed. It can be simplified.

  In addition, since the receiving surface is a plane substantially perpendicular to the optical axis, the position of the light emitting point does not change in the optical axis direction even if the contact portion of the laser holder is moved in contact with the receiving surface. That is, even if the angle adjustment or the position adjustment is performed, the position does not change with respect to the optical axis direction of the light emitting point. Therefore, the angle adjustment and the position adjustment can be performed at the same time, whereby the adjustment work can be performed smoothly. .

  Also, the portion that contacts the receiving surface is the ridgeline portion of the laser holder, and even if the laser holder is tilted, the portion where the laser holder contacts the receiving surface does not change, so the light emitting point is always on the same plane as the receiving surface. Axial misalignment is minimized.

  Further, since the laser holder is not configured to be fixed to the holder cradle by a connecting member such as a screw, the number of components can be reduced. Further, when adjusting the angle or adjusting the position, it is not necessary to put in and out screws and the like, and the adjustment work time is shortened.

  Further, since the holder cradle has a flat receiving surface, it can be easily processed with high accuracy, and since no adjustment screw hole or the like is provided, the manufacturing cost can be reduced.

  Further, since the abutting portion is composed of two planes, the abutting portion can be easily formed with high accuracy.

  Further, the optical head according to the present invention is characterized in that a pair of the contact portions are formed at two opposing positions of the frame body.

  With this configuration, the laser holder is brought into contact with the receiving surface by the ridge line portions arranged in parallel at two opposing positions, so that the laser holder is stably supported by the holder base.

  In the optical head according to the present invention, the laser holder has a top corresponding to the abutting portion on a head opposed to the bottom, and the top is an arc whose center axis is the ridge line portion. It is a protrusion consisting of a surface, and the holder cradle has means for pressing the top of the head with a pressing member having a flat pressing surface perpendicular to the optical axis.

  With this configuration, since the laser holder is pressed and supported on the holder cradle by the pressing means, the posture of the laser holder is always kept constant, and the position and angle of the laser holder can be easily adjusted. It is also easier to do. That is, in the case where the posture of the laser holder is not maintained, the adjusted state needs to be temporarily fixed with a jig or the like, but such temporary fixing is not necessary.

  Further, since the laser holder is not pressed from the direction other than the optical axis direction of the optical head (direction perpendicular to the optical axis) by the pressing means, it can be easily moved in the direction perpendicular to the optical axis. Can be easily tilted.

  The top of the head is an arc surface having a central axis that coincides with the ridge line portion, and even if the laser holder is tilted, the laser holder rotates with respect to the ridge line portion. The distance between the abutting point that abuts and the pressing contact at which the top of the head contacts the pressing surface does not change. That is, since the distance between the contact point and the pressing contact is constant, the force with which the pressing member presses the top of the head does not change, and the laser holder is pressed and supported in a stable state at all times.

  The top of the head is an arc surface having a central axis coinciding with the ridge line, and the receiving surface and the pressing surface are perpendicular to the optical axis and are parallel to each other. Even if it is rotated, the pressing direction of the pressing surface is always the optical axis direction, so that the laser holder is pressed and supported in a stable posture.

  The optical head according to the present invention is characterized in that the holder cradle is integrated with a housing of an optical pickup device.

  With this configuration, since the laser holder is directly mounted on the housing of the optical pickup device without using the holder cradle, the number of parts as the holder cradle can be reduced, and the manufacturing cost can be reduced.

  An optical pickup device according to the present invention is an optical pickup device for recording / reproducing information by irradiating an information recording medium with a laser beam from an optical head, wherein the optical head is the optical head according to the present invention. To do.

  With this configuration, the optical axis adjustment of the laser optical axis of the optical pickup device can be easily performed, so that the optical axis adjustment work efficiency can be improved.

  According to the optical head according to the invention, the laser holder for fixing the laser diode has an abutting portion made of an arc surface having a central axis perpendicular to the optical axis of the optical head and passing through the light emitting point. The holder pedestal has a planar receiving surface perpendicular to the optical axis of the optical head, and the contact portion is in contact with the receiving surface, so that the laser light emission point is set in the optical axis direction. The angle and position of the laser holder can be adjusted without changing the position.

  Further, according to the optical head according to the present invention, since the abutting portions are formed at two distant locations, the laser holder is stably supported by the holder cradle.

  In addition, according to the optical head of the present invention, the laser holder has a structure that is held so as to press against the holder cradle, so that the optical axis of the laser light can be easily adjusted.

  Further, according to the optical head of the present invention, the laser holder is always pressed against the holder cradle with a constant pressure, so that the laser holder can be always fixed in a stable posture.

  Further, according to the optical head according to the present invention, since the variation in the radius of the contact portion is small, the position of the light emitting point does not change greatly in the optical axis direction by adjusting the tilt of the laser holder.

  In addition, according to the optical head of the present invention, the gap between the laser holder and the holder cradle is reduced by the tapered surface provided in the contact portion, so that the heat dissipation of the optical head can be improved.

  According to the optical head of the present invention, the laser holder has a ridge line portion that is perpendicular to the optical axis of the optical head and coincides with the central axis passing through the light emitting point, while the holder cradle is provided with the optical head. Since the ridge line portion is in contact with the receiving surface, the laser holder is positioned without changing the position of the laser light emission point in the optical axis direction. Angle adjustment and position adjustment can be performed.

  Further, according to the optical head according to the present invention, since the laser holder is in direct contact with the receiving surface formed on the housing of the optical pickup device, parts as a holder cradle can be omitted, and the manufacturing cost can be reduced. Can be reduced.

  According to the optical pickup device of the present invention, since the optical head of the present invention is mounted, the optical axis adjustment of the laser diode can be easily adjusted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Embodiment 1>
An optical head according to Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1 is a perspective view of an optical head according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view showing the laser holder and holder holder of the optical head according to the first embodiment of the present invention separately. FIG. 3 is a schematic cross-sectional view of the optical head as viewed from the arrows AA in FIG. 1 in a state where the laser holder central axis and the optical head central axis coincide with each other. FIG. 4 is a schematic cross-sectional view of the optical head viewed from the arrow AA in FIG. 1 in a state where the laser holder central axis is tilted with respect to the optical head central axis. FIG. 5 is a schematic cross-sectional view of the optical head viewed from the arrows AA in FIG. 1 in a state where the laser holder central axis is tilted with respect to the optical head central axis and moved in the Y direction.

  In FIG. 2, the pressing member 51 as a component is not shown.

  In the optical pickup device, laser light emitted from the laser diode 11 of the optical head 1 is collimated by a collimator lens, shaped into a circular beam by a beam shaping prism, and collected on an information recording medium by an objective lens via a beam splitter. Lighted. Reflected light reflected from the information recording medium is detected by a photodetector to read information. These optical components are arranged so that their optical axes coincide with the optical axis of the optical pickup device. As a result, the laser beam is focused on the information recording medium in an appropriate state, so that the focused position does not deviate from the track of the information recording medium, and tracking information and the like are stably generated without causing a tracking error. It can be detected.

  Therefore, the laser diode 11 is arranged so that the optical axis of the laser light coincides with the optical axis of the optical pickup device. However, the optical axis of the laser light from the laser diode 11 is different depending on each product. Therefore, for the purpose of adjusting the optical axis of the laser light, the optical head 1 that fixes and supports the laser diode 11 is provided with a structure for adjusting the emission angle of the laser light and the position of the light emitting point of the laser diode 11. Yes. Hereinafter, the structure of the optical head 1 will be described.

  The optical head 1 includes a laser diode 11, a laser holder 21 that holds the laser diode 11, and a holder cradle 31 that supports and supports the laser holder 21. Each component is arranged based on the optical axis P of the optical head 1.

  The laser holder 21 is a cylindrical frame composed of four side walls, and the laser holder central axis CH passing through the center of the frame is arranged so as to coincide with the optical axis P of the optical head 1. The laser diode 11 is fixed inside the frame of the laser holder 21 so that the laser diode central axis CL and the laser holder central axis CH coincide with each other. Since the optical axis P of the optical head 1 coincides with the optical axis of the optical pickup device, the laser diode central axis CL and the laser holder central axis CH are arranged so as to coincide with the optical axis of the optical pickup device (FIG. 2). reference).

  Although the optical axis of the laser light emitted from the laser diode 11 varies depending on the product, it substantially coincides with the laser diode central axis CL, and therefore substantially coincides with the optical axis of the optical pickup device. Therefore, the adjustment of the optical axis of the laser beam is an adjustment operation for bringing the optical axes that are substantially coincident into a more optimal state.

  A pair of abutting portions 23 project from the bottom portion 21b of the two opposite side walls of the laser holder 21 so as to sandwich the laser beam emission port. Each contact portion 23 is configured by an arc surface having a radius r and having a central axis C that passes through the light emitting point EP of the laser diode 11 and is perpendicular to the optical axis P of the optical head 1. Therefore, the light emission point EP of the laser diode 11 is located at a certain distance H1 from the receiving surface 32 in contact with both contact portions 23, 23 (see FIG. 3).

  Note that the abutting portion 23 may be formed only at one place on the bottom of an arbitrary side wall.

  A head portion 24 projects from the head portion 21 a facing the bottom portion 21 b of the frame of the laser holder 21 so as to correspond to each contact portion 23. Both the head apex portions 24 and 24 are formed by circular arc surfaces with a radius R having a central axis C that passes through the light emitting point EP of the laser diode 11 and is perpendicular to the optical axis P of the optical head 1. Therefore, the light emission point EP of the laser diode 11 is located at a certain distance H2 from the pressing surface 43 in contact with the tops 24, 24 (see FIG. 3).

  Further, the distance (radius r) from the central axis C to the arc surface constituting the contact portion 23 is formed smaller than the distance (radius R) from the central axis C to the arc surface constituting the crown 24. . The variation in the radius r of the arc surface is smaller when the radius r is smaller. Therefore, the contact portion 23 is configured from the central axis C by relatively reducing the radius of the arc surface forming the contact portion 23. Variations in distance to the arc surface can be reduced. Therefore, when the laser holder 11 is tilted during the laser optical axis adjustment, the contact point between the contact portion 23 and the receiving surface 32 changes, but the distance from the central axis C to the arc surface constituting the contact portion 23 varies. Since the variation is small, the distance from the light emitting point EP to the receiving surface 32 hardly changes.

  The holder pedestal 31 is mounted on a housing (not shown) of the optical pickup device with the laser holder 21 being in contact with and supported. That is, the laser holder 21 is fixed to the housing via the holder cradle 31.

  The holder receiving base 31 has a flat receiving surface 32 that comes into contact with the pair of contact portions 23, 23 of the laser holder 21. The receiving surface 32 is provided with a through hole 33 through which laser light passes, and the central axis of the through hole 33 is made to coincide with the optical axis P of the optical head 1. The receiving surface 32 is formed so as to be perpendicular to the optical axis P of the optical head 1. As a result, even if the laser holder 21 is moved in the direction (XY direction) perpendicular to the optical axis P of the optical head 1, the position of the light emitting point EP does not change with respect to the optical axis direction (Z direction). Yes.

  The holder cradle 31 is provided with pressing means (34, 41) for pressing the laser holder 21 against the receiving surface 32. As a result, the laser holder 21 is pressed against the holder cradle 31, and the posture of the laser holder 21 is maintained.

  Specifically, the pressing means includes a pair of guide portions 34 provided on both sides of the laser holder 21 and a pressing member 41 provided on the guide head portion 34a (see FIG. 1). . The guide part 34 is arranged in parallel with the holder cradle 31 at a certain distance from the laser holder 21. This interval is provided because the laser holder 21 may be moved in the direction (XY direction) perpendicular to the optical axis P of the optical head 1 when adjusting the optical axis of the laser light.

  The guide head 34 a is provided with an engagement groove 37 that engages with the pressing member 41, and a screw hole 36 for screwing a screw 51 that fixes the pressing member 41 to the guide portion 34. Are fixed to the guide head 34a with screws 51.

  The pressing member 41 has a pressing surface 43 formed in a flat shape, and is disposed so as to press the top 24 with the pressing surface 43 being perpendicular to the optical axis P of the optical head 1 (FIG. 3). reference).

  Since the abutting portion 23 and the head portion 24 are formed by an arc surface having a central axis C that passes through the light emission point EP and is perpendicular to the optical axis P of the optical head 1, the laser holder 21 is tilted even if the laser holder 21 is tilted. Is rotated with respect to the central axis C, the distance between the contact point where the contact portion 23 contacts the receiving surface 32 and the central axis C, and the pressing contact where the crown 24 contacts the pressing surface 43 and the central axis. The distance from C does not change. That is, since the distance between the contact point and the pressing contact is constant, the force with which the pressing member 41 presses the top 24 is not changed, and the laser holder 21 is pressed and supported in a stable state at all times.

  Since the receiving surface 32 and the pressing surface 43 are planes perpendicular to the optical axis P of the optical head 1 and parallel to each other, the laser holder 21 is tilted and rotated with respect to the central axis C. However, since the pressing direction of the pressing surface 43 is always the optical axis direction, the laser holder 21 is pressed and supported in a stable posture.

  The pressing member 41 is a leaf spring made of, for example, a metal such as iron, copper, or aluminum, or plastic.

  Further, the pressing means constituted by the guide part 34 and the pressing member 41 may be configured by integrating the guide part 34 and the pressing member 41 to form a metal part in parallel with the laser holder 21. In this way, by making the pressing means a removable guide part, it is possible to cope with laser holders having various heights simply by exchanging them.

  Alternatively, the pressing member 41 may be formed to extend from the guide portion 34, and the pressing member 41, the guide portion 34, and the holder pedestal 31 may be integrated. As a result, the number of parts can be reduced.

  Next, angle adjustment and position adjustment of the laser holder 21 performed when the optical axis of the laser light is aligned with the optical axis P of the optical head 1 will be described.

  First, the optical head 1 is held by an optical head adjustment jig (not shown), and the angle and position of the laser holder 21 are adjusted with respect to the holder cradle 31. For example, the laser holder 21 is tilted or moved by the adjustment arm of the optical head adjustment jig.

  Specifically, when the optical axis of the laser beam is shifted by an angle θ with respect to the optical axis P of the optical head 1, the laser holder 21 is tilted by an angle −θ with respect to the optical axis P of the optical head 1. (See FIG. 4). The angle adjustment is performed by tilting the laser holder 21 while bringing the contact portion 23 of the laser holder 21 into contact with the receiving surface 32.

  As described above, even when the laser holder 21 is tilted for adjusting the optical axis of the laser light, the receiving surface 32 is a plane substantially perpendicular to the optical axis P of the optical head 1 and is in contact with the receiving surface 32. Since the contact portion 23 is formed of an arc surface having a central axis C passing through the light emission point EP and parallel to the receiving surface 32, the laser holder 21 rotates with respect to the central axis C. The position of EP does not change in the optical axis direction (Z direction) (see FIG. 4).

  Further, when the mounting position of the laser diode chip is shifted, the light emitting point EP is shifted by a distance y from the predetermined position, and the optical axis of the laser beam is shifted by the angle θ with respect to the optical axis P of the optical head 1. In other words, the laser holder 21 is tilted by an angle −θ with respect to the optical axis P of the optical head 1 while moving the distance −y in a direction perpendicular to the optical axis P of the optical head 1. The angle adjustment and the position adjustment are performed by moving the laser holder 21 while bringing the contact portion 23 into contact with the receiving surface 32.

  Thus, even if the abutting portion 23 of the laser holder 21 abuts on the receiving surface 32 and moves in parallel, the receiving surface 32 is a plane substantially perpendicular to the optical axis P of the optical head 1, The position of EP does not change in the optical axis direction (Z direction) (see FIG. 5).

  As a result, there is no position change in the optical axis direction of the optical head 1 (that is, the distance direction between the light emitting point and the collimator lens), so the distance between the light emitting point of the laser diode 11 and the collimator lens does not change, and the focal length is Since it does not change, adjusting the optical axis does not change the parallelism of the laser light that is converted into parallel light through the collimator lens. Therefore, the light spot that narrows the focal point of the laser light and irradiates the information recording medium The shape does not change. That is, when adjusting the optical axis of the laser light, it is not necessary to take into account the change in the parallelism of the laser that is converted into parallel light through the collimator, so that the optical axis of the laser light can be easily adjusted.

  Moreover, you may perform angle adjustment and position adjustment of the laser holder 21 simultaneously. That is, conventionally, since the position of the light emission point EP has changed in the optical axis direction when the angle of the laser holder 21 is changed, it has been necessary to adjust the position of the light emission point each time the angle is changed. Since there is no need to perform position correction by angle adjustment, both the angle and the position can be adjusted to the optimum state even if the angle adjustment and the position adjustment are performed simultaneously. In addition, the adjustment time is shortened by the amount that can be performed simultaneously.

  Further, since the laser holder 21 is not pressed from the direction (XY direction) other than the optical axis direction of the optical head 1 by the pressing means, it can be freely moved in the direction (XY direction) perpendicular to the optical axis P of the optical head 1. Thus, the adjustment in the direction (XY direction) perpendicular to the optical axis P of the optical head 1 is easy. That is, since the laser holder 21 is not configured to be fixed to the holder cradle 31 or the like by a connecting member such as a screw, when adjusting the angle or adjusting the position, the connecting part such as the screw is once loosened and the position is adjusted, After that, there is no need to retighten the connecting parts such as screws, and the adjustment work time can be shortened.

  After the optical axis adjustment, the optical head 1 is removed from the optical head adjustment jig and the laser holder 21 is fixed with an adhesive so that the adjusted state does not collapse.

  Even when the optical head 1 is removed from the optical head adjustment jig, the laser holder 21 is pressed and supported by the holder cradle 31 by the pressing means, and the posture of the laser holder 21 is always maintained. It is easy to work. That is, in the case where the posture of the laser holder 21 is not maintained, the adjusted state needs to be temporarily fixed with a jig or the like, but such temporary fixing is not necessary.

<Embodiment 2>
An optical head according to Embodiment 2 of the present invention will be described with reference to FIG.

  FIG. 6 is a schematic cross-sectional view of the same position as the arrow AA in FIG. 1 in the optical head according to Embodiment 2 of the present invention, in which the center axis of the laser holder and the optical axis of the optical head coincide with each other. FIG.

  The present embodiment is substantially the same as the configuration of the first embodiment. That is, the optical head 1 includes a laser diode 11, a laser holder 21 that holds the laser diode 11, a laser holder 21, and a holder cradle 31 that abuts and supports, and is different from the first embodiment. Since the point is only the structure of the contact portion 23, this point will be described.

  As in the first embodiment, the contact portion 23 provided on the laser holder 21 has a pair of contact portions 23 projecting from the bottom portion 21b of the frame of the laser holder 21 so as to sandwich the laser beam emission port. It is. Both abutting portions 23, 23 are constituted by circular arc surfaces with a radius r having a central axis C passing through the light emitting point EP of the laser diode 11 and perpendicular to the optical axis P of the optical head 1. Therefore, the light emission point EP of the laser diode 11 is located at a certain distance from the receiving surface 32 in contact with both the abutting portions 23 and 23.

  Each contact portion 23 is formed with tapered surfaces 27 and 27 that continuously circumscribe the arc surface at a predetermined angle. That is, the gap between the laser holder 21 and the holder pedestal 31 that is formed by providing the contact portion 23 on the laser holder 21 is reduced. As a result, heat generated from the laser diode 11 is transmitted to the holder cradle 31 via the laser holder 21, so that the heat dissipation of the optical head 1 is improved.

  In addition, you may improve the heat dissipation of the optical head 1 by comprising the pressing member 41 of the holder cradle 31 with materials with high heat | fever tradition rates, such as iron and copper.

  Furthermore, the heat dissipation of the optical head 1 may be improved by increasing the area where the top 24 of the holder cradle 31 and the pressing member 41 abut. That is, by increasing the radius of the arcuate surface constituting the crown 24, the area where the crown 24 and the pressing member 41 abut may be increased to improve heat dissipation.

  Thereby, the lifetime of the laser diode 11 can be extended.

<Embodiment 3>
An optical head according to Embodiment 3 of the present invention will be described with reference to FIG.

  FIG. 7 is a schematic cross-sectional view of the same position as the arrow AA in FIG. 1 in the optical head according to Embodiment 3 of the present invention, in which the center axis of the laser holder matches the optical axis of the optical head. It is a section schematic diagram showing a state.

  The optical head 1 according to the present embodiment includes a laser diode 11, a laser holder 21 that holds the laser diode 11, and a holder base 31 that abuts and supports the laser holder 21. Each component is arranged based on the optical axis P of the optical head 1.

  The laser holder 21 is a cylindrical frame constituted by four side walls, and the laser holder central axis CH passing through the center of the frame is arranged so as to coincide with the optical axis P of the optical head 1. The laser diode 11 is fixed inside the frame of the laser holder 21 so that the laser diode central axis CL and the laser holder central axis CH coincide with each other. Since the optical axis P of the optical head 1 coincides with the optical axis of the optical pickup device, the laser diode central axis CL and the laser holder central axis CH are arranged so as to coincide with the optical axis of the optical pickup device.

  A pair of contact portions 23 project from the bottom portion 21b of the frame of the laser holder 21 so as to sandwich the laser light emission port. Each contact portion 23 is a projection having a ridge line portion 25 formed by intersecting two planes 29, 29, and both ridge line portions 25, 25 pass through the light emitting point EP of the laser diode 11 and light of the optical head 1. It coincides with a straight line perpendicular to the axis P. Therefore, the light emission point EP of the laser diode 11 is on the same line as both the ridge line portions 25 and 25 and is on the same plane as the receiving surface 32 in contact with the ridge line portion 25.

  On the head 21 a facing the bottom 21 b of the frame of the laser holder 21, a top 24 is protruded so as to correspond to each contact portion 23, 23. Both the head apex portions 24 and 24 are configured by circular arc surfaces having a radius having a central axis C (that is, a straight line passing through the ridge line portion 25) passing through the light emitting point EP of the laser diode 11 and perpendicular to the optical axis P of the optical head 1. . Therefore, the light emission point EP of the laser diode 11 is located at a certain distance H3 from the pressing surface 43 in contact with the tops 24, 24.

  The holder cradle 31 contacts and supports the laser holder 21 and is mounted on a housing (not shown) of the optical pickup device. That is, the laser holder 21 is fixed to the housing via the holder cradle 31.

  The holder cradle 31 has a planar receiving surface 32 that comes into contact with the pair of ridge line portions 25, 25 of the laser holder 21. The receiving surface 32 is provided with a through-hole 33 through which laser light passes. The central axis of the through-hole 33 coincides with the optical axis P of the optical head 1. The receiving surface 32 is formed to be perpendicular to the optical axis P of the optical head 1.

  With such a configuration, angle adjustment and position adjustment of the optical head 1 can be easily performed. That is, the ridge line portion 25 coincides with a straight line passing through the light emission point EP and is in contact with the receiving surface 32. Even if the laser holder 21 is tilted to adjust the optical axis of the laser beam, the laser holder 21 remains in the ridge line portion. Therefore, the position of the light emitting point EP does not change in the optical axis direction of the optical head 1. Further, since the receiving surface 32 is a plane substantially perpendicular to the optical axis of the optical head 1, even if the ridge line portion 25 of the laser holder 21 is moved in contact with the receiving surface 32, the position of the light emitting point EP remains at the optical axis. Does not change direction.

  Thereby, the angle adjustment of the irradiation angle of the laser beam and the position adjustment of the light emitting point of the laser diode 11 can be performed simultaneously.

  The holder cradle 31 is provided with pressing means for pressing the laser holder 21 against the receiving surface 32. As a result, the laser holder 21 is pressed against the holder cradle 31, and the posture of the laser holder 21 is maintained.

  Since the specific pressing means is the same as that shown in the first embodiment, the description thereof is omitted.

  Further, the angle adjustment and the position adjustment of the laser holder 21 are the same as those in the first embodiment, and thus the description thereof is omitted.

<Embodiment 4>
An optical head according to Embodiment 4 of the present invention will be described with reference to FIG.

  FIG. 8 is a perspective view of an optical head according to Embodiment 4 of the present invention.

  In the present embodiment, the above-described holder cradle 31 is integrated with the housing 61 of the optical pickup device.

  The optical head 1 according to the present embodiment includes a laser diode 11, a laser holder 21 that holds the laser diode 11, and a housing 61 in which a holder pedestal 31 that abuts and supports the laser holder 21 is integrated. is there. As a result, the optical head 1 is directly mounted on the housing 61 of the optical pickup device, and parts as the holder cradle 31 are no longer required, so that the product cost is reduced accordingly.

  The laser holder 21 may be any of the first to third embodiments. That is, the laser diode 11 is fixed to the laser holder 21, and a contact portion 23 that contacts the receiving surface 32 formed on the housing 61 is formed on the bottom portion 21 b of the frame of the laser holder 21. .

  The housing 61 is a housing in which components constituting the laser holder 21 and other optical pickup devices, such as a collimator lens, a prism, an objective lens, and a photodetector, are mounted.

  The housing 61 is provided with a planar receiving surface 32 on which the pair of contact portions 23, 23 of the laser holder 21 abut. The receiving surface 32 is provided with a through-hole 33 through which laser light passes. The central axis of the through-hole 33 coincides with the optical axis P of the optical head 1. The receiving surface 32 is formed to be perpendicular to the optical axis P of the optical head 1.

  With such a configuration, the same effect as in the first embodiment can be obtained. That is, even if the laser holder 21 is tilted to adjust the optical axis of the laser light, the laser holder 21 rotates with respect to the central axis C passing through the light emitting point EP and perpendicular to the optical axis P of the optical head 1. Therefore, the position of the light emission point EP does not change in the optical axis direction. Even if the position of the laser holder 21 is adjusted in the direction (XY direction) perpendicular to the optical axis P of the optical head 1 and the position of the light emission point EP of the laser light is adjusted, the position of the light emission point EP remains in the optical axis direction. It does not change in the (Z direction). In addition, even if angle adjustment or position adjustment is performed, the position does not change with respect to the optical axis direction of the light emitting point EP, so that angle adjustment and position adjustment can be performed simultaneously.

  The housing 61 is provided with pressing means for pressing the laser holder 21 toward the receiving surface 32. As a result, the laser holder 21 is pressed against the receiving surface 32 and the posture of the laser holder 21 is maintained.

  Since the specific pressing means is the same as that shown in the first embodiment, the description thereof is omitted.

  Next, a method for adjusting the optical head 1 will be described.

  When the optical axis P of the optical head 1 is adjusted before the optical component is mounted on the housing 61, as in the first embodiment, the optical head 1 is held by the optical head adjustment jig, and the angle of the laser holder 21 is adjusted. The position is adjusted.

  When the optical axis P of the optical head 1 is adjusted after the optical component is mounted on the housing 61, the optical pickup device functions as an optical pickup device. Therefore, the light of the optical head 1 is measured while directly measuring the output of the photodetector. Axis adjustment is performed. In this case, the optical axis is not misaligned when the optical head 1 is mounted, so that the optical axis can be adjusted more optimally.

<Embodiment 5>
An optical pickup device (not shown) according to Embodiment 5 of the present invention will be described.

  The optical pickup device includes the optical head 1 described in the first to fourth embodiments, a collimator lens that converts the laser light emitted from the laser diode 11 into parallel light, a shaping prism that shapes the parallel laser light into a circular shape, It comprises an objective lens that irradiates the shaped laser beam with a focused focus, a detector that receives light reflected from the information recording medium and detects a signal.

  With this configuration, even if the laser holder 21 is tilted in order to adjust the optical axis of the laser light of the laser diode 11, the position change in the optical axis direction of the optical head 1 (that is, the distance direction between the light emitting point and the collimator lens). Therefore, the distance between the light emitting point of the laser diode 11 and the collimator lens does not change, and the focal length does not change. In other words, by adjusting the optical axis, there is no change in the parallelism of the laser light that is made parallel through the collimator lens, and there is no change in the shape of the light spot that squeezes the focal point of the laser light and irradiates the information recording medium. Therefore, the optical axis adjustment of the optical pickup device can be facilitated. Therefore, the production efficiency of the optical pickup device can be improved.

1 is a perspective view of an optical head according to Embodiment 1 of the present invention. FIG. 3 is an exploded perspective view showing a laser holder and a holder cradle of the optical head according to Embodiment 1 of the present invention separately. FIG. 2 is a schematic cross-sectional view of the optical head viewed from the arrow AA in FIG. 1 in a state in which a laser holder central axis and an optical head central axis are aligned. FIG. 2 is a schematic cross-sectional view of the optical head viewed from the arrow AA in FIG. 1 in a state where the laser holder central axis is inclined with respect to the optical head central axis. FIG. 2 is a schematic cross-sectional view of the optical head viewed from the arrows AA in FIG. 1 in a state where the laser holder central axis is tilted with respect to the optical head central axis and moved in the Y direction. In the optical head concerning Embodiment 2 of this invention, it is the cross-sectional schematic of the same location as arrow AA in FIG. 1, and the cross section which shows the state with which the center axis | shaft of the laser holder and the optical axis of the optical head corresponded FIG. In the optical head concerning Embodiment 3 of this invention, it is the cross-sectional schematic of the same location as arrow AA of FIG. 1, and the cross section which shows the state with which the central axis of the laser holder and the optical axis of the optical head corresponded FIG. It is a perspective view of the optical head which concerns on Embodiment 4 of this invention. FIG. 6 is a schematic diagram of an optical head of Conventional Example 1. 10 is a schematic diagram of an optical head of Conventional Example 2. FIG. 10 is a schematic diagram of an optical head of Conventional Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical head 11 Laser diode 21 Laser holder 21a Head 21b Bottom 23 Contact part 24 Top part 25 Ridge part 27 Tapered surface 29 Plane 31 Holder stand 32 Receiving surface 33 Through-hole 34 Guide part (Pressing means)
34a Guide head 41 Pressing member (pressing means)
43 Pressing surface 61 Housing EP Light emitting point P Optical axis of optical head 1 CH Holder central axis CL Laser diode central axis

Claims (11)

In an optical head comprising a laser holder for holding a laser diode, and a holder cradle for holding the laser holder, and recording / reproducing information by irradiating an information recording medium with laser light from the laser diode,
The laser holder is a frame that fixes the laser diode, and has a contact portion protruding from the bottom of the frame,
The holder cradle has a receiving surface for abutting and supporting the abutting portion and a through-hole for allowing the laser beam to pass through,
The receiving surface is a plane substantially perpendicular to the optical axis of the optical head, and the contact portion is an arc surface having a central axis that passes through the light emitting point of the laser diode and is perpendicular to the optical axis. Light head to play.   The optical head according to claim 1, wherein a pair of the contact portions are formed at two opposing positions of the frame body.   The laser holder has a top corresponding to the abutting portion on a head opposed to the bottom, and the holder cradle presses the top in a direction in which the abutting portion presses the receiving surface. The optical head according to claim 1, further comprising a pressing unit that performs the pressing operation. The top of the head is a projection made of an arc surface having the central axis,
The optical head according to claim 3, wherein the pressing unit is configured to press the top portion with a pressing member having a flat pressing surface perpendicular to the optical axis.   The optical head according to claim 4, wherein a distance from the central axis to the arc surface of the abutting portion is smaller than a distance from the central axis to the arc surface of the top of the head.   6. The optical head according to claim 1, wherein the contact portion has a tapered surface that continuously circumscribes the arc surface. In an optical head comprising a laser holder for holding a laser diode, and a holder cradle for holding the laser holder, and recording / reproducing information by irradiating an information recording medium with laser light from the laser diode,
The laser holder is a frame that fixes the laser diode, and a bottom portion of the frame is provided with a contact portion projecting a ridge line portion where two planes intersect,
The holder cradle has a receiving surface for abutting and supporting the abutting portion and a through-hole for allowing the laser beam to pass through,
The receiving surface is a plane substantially perpendicular to the optical axis of the optical head, and the ridge line portion coincides with a straight line passing through a light emitting point of the laser diode and perpendicular to the optical axis. head.   The optical head according to claim 7, wherein a pair of the contact portions are formed at two opposing positions of the frame body. The laser holder has a top corresponding to the abutting portion on a head opposite to the bottom, and the top is a protrusion made of an arc surface having the ridge line portion as a central axis,
9. The optical head according to claim 7, wherein the holder pedestal includes means for pressing the top of the head with a pressing member having a flat pressing surface perpendicular to the optical axis.   The optical head according to claim 1, wherein the holder pedestal is integrated with a housing of an optical pickup device. In an optical pickup apparatus for recording / reproducing information by irradiating an information recording medium with a laser beam from an optical head,
11. The optical pickup device according to claim 1, wherein the optical head is the optical head according to any one of claims 1 to 10.

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