JP2008077757A - Positioning mechanism of columnar lens, optical head, and optical recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning mechanism having a simple constitution in which rotation of a columnar lens is prevented, while smooth movement in a longitudinal direction can be performed. <P>SOLUTION: A housing 2 is provided with a V-shaped groove 18 is composed of a pair of slopes 18a and an engaging concave part 19 of a bottom part of the V-shaped groove 18, and a columnar sensor lens 15 is provided with a convex part 20 for positioning extended to the longitudinal direction. The convex part 20 is composed of a narrow width part and a wide width part continued in the longitudinal direction, the concave part 19 for engaging is also composed of the narrow width part and the wide width part in the same way and reverse insertion is prevented. When the sensor lens 15 is inserted into the V-shaped groove 18, the convex part 20 is engaged to the concave part 19 and slidable in the longitudinal direction in the concave part 19, and an outer peripheral plane of the sensor lens 15 is line-contacted to the pair of slopes 18a respectively and held. Projection parts 22 of both side parts of the sensor lens 15 are held in a state in which they are spaced on the surface of the housing 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical head for recording or reproducing data on an optical recording medium such as an optical disc, a positioning mechanism for a cylindrical lens built in the optical head, and an optical recording / reproducing apparatus including the optical head.

  In an optical head of an optical recording / reproducing apparatus used for recording or reproducing an optical recording medium such as a CD (Compact disk) or a DVD (digital versatile disk), a housing, an optical component such as a lens, a laser diode, a photodetector, a polarizing beam splitter Is installed. These optical components need to accurately align their optical axes at desired positions.

  In such an optical head, a cylindrical lens may be used to collect light on the light receiving surface of the photodetector. In order to focus the light accurately on the light receiving surface of the photodetector, this cylindrical lens may require fine adjustment of the distance from the photodetector. In this case, the cylindrical lens is moved in the longitudinal direction. Let For example, in the optical head manufacturing process, after the cylindrical lens is temporarily arranged on the housing, the cylindrical lens is moved in the longitudinal direction while actually irradiating the laser beam and finely adjusted to reach the optimum position. At the time, the cylindrical lens is fixed to the housing. When the cylindrical lens has an aspherical lens shape, the light converging state on the light receiving surface of the photodetector may be deteriorated by rotating the cylindrical lens in the circumferential direction. Accordingly, there is a need for a positioning mechanism that can be finely adjusted by moving the cylindrical lens in the longitudinal direction on the housing and that prevents circumferential rotation.

  Conventionally, a cylindrical lens is housed in a quadrangular prism-shaped case so that the outer shape is square, and the housing is provided with an upper flat surface and a wall surface perpendicular to it, and the four rectangular surfaces of the case containing the cylindrical lens. There is a configuration in which two of these are in contact with the upper plane of the housing and a wall surface perpendicular thereto. According to this configuration, the two rectangular surfaces of the case enclosing the cylindrical lens that are orthogonal to each other are slid along the two surfaces of the housing, thereby preventing the rotation of the cylindrical lens in the longitudinal direction. The position can be adjusted.

  Patent Document 1 discloses a sensor lens mounting mechanism in which a plate-like flange is joined to a cylindrical lens. In this mechanism, the frame (housing) is provided with a concave portion large enough to accommodate the cylindrical portion of the sensor lens, and both side portions of the plate-like flange are placed on the upper surface of the frame on both sides of the concave portion. As a result, the cylindrical portion of the sensor lens is held in a state of hanging in the recess.

Patent Document 2 discloses a configuration in which a support arm is provided on each side of a cylindrical lens, a support arm is also provided in a lower portion, and a groove (which accommodates approximately half of the cylindrical lens) is provided in a frame (housing). Has been. This groove has a notch at the bottom. The support arms on both sides of the cylindrical lens are placed on the upper surface of the frame on both sides of the groove, so that the lower part of the cylindrical lens is held in a state of hanging in the recess. The lower support frame of the cylindrical lens is accommodated in a notch at the bottom of the groove, and is pressed against one inner surface (support surface) of the notch by a pressing spring to prevent rotation.
JP-A-10-283639 JP 2000-266977 A

  In the case where the cylindrical lens is housed in a quadrangular prism case, the cylindrical lens and the case are integrated with each other while the two orthogonal surfaces of the quadrangular prism case are in contact with the two surfaces of the frame. Since it is slid in the longitudinal direction, the contact area between the case and the frame is large and the frictional force is large. Therefore, the movement of the cylindrical lens in the longitudinal direction is not easy and smooth. Further, since the cylindrical lens is accommodated in the quadrangular prism case, manufacturing and assembly are relatively troublesome, and the entire outer shape becomes larger than necessary.

  In the configuration described in Patent Document 1, a large concave portion that accommodates the cylindrical portion of the sensor lens must be formed in the frame, and a circular opening that allows incident light to the sensor lens to pass through the sensor lens. It is necessary to form a circular opening through which the outgoing light passes. Therefore, the frame is relatively large and its manufacture is very complicated. Further, even in the configuration described in Patent Document 1, since both side portions of the plate-like flange are in surface contact with the upper surface of the frame, the contact area is large and the frictional force is large, so that the cylindrical lens is moved in the longitudinal direction. Easy and not smooth.

  In the configuration described in Patent Document 2, a pressing spring for pressing the lower support arm of the cylindrical lens to one inner surface (support surface) of the notch portion must be mounted in the notch portion. In the notch, it is very complicated to load the presser spring in a very narrow space between the other inner surface and the support arm. In the configuration described in Patent Document 2, since the support arms on both sides of the cylindrical lens are in surface contact with the upper surface of the frame, the contact area is large and the frictional force is large, so that the longitudinal direction of the cylindrical lens is increased. The movement is not easy and smooth.

  As described above, any of the conventional configurations has a drawback that the frictional force serving as resistance to movement of the cylindrical lens in the longitudinal direction is large. In any of the configurations described in Patent Documents 1 and 2, the cylindrical lens is held in a state where it is suspended in the recess or in the groove. Therefore, in the normal design philosophy, the support portion is in surface contact, increasing the contact area and friction. The increase of is inevitable. In the configuration in which the cylindrical lens is accommodated in the quadrangular prism case, since the rotation prevention function is realized by bringing the lens into a surface contact state, an increase in contact area and an increase in friction due to the surface contact are inevitable.

  In addition, the formation of the circular opening of Patent Document 1 and the mounting of the holding spring of Patent Document 2 in the notch portion require technically very complicated work if not impossible.

  Accordingly, an object of the present invention is to provide a cylindrical lens that has a small frictional resistance against the movement of the cylindrical lens in the longitudinal direction, can be easily and smoothly moved, prevents the cylindrical lens from rotating, and is easy to manufacture. A positioning mechanism, an optical head including the same, and an optical recording / reproducing apparatus including the optical head are provided.

  The present invention relates to a cylindrical lens positioning mechanism that includes a housing and a cylindrical lens mounted on the housing, and the housing is opposed to each other and is inclined so that the distance between each other gradually decreases. The cylindrical lens is provided with a V-shaped groove composed of a slanted surface, and a recess extending along the longitudinal direction of the V-shaped groove. A convex portion extending along the longitudinal direction is provided. When the cylindrical lens is inserted into the V-shaped groove, the convex portion fits into the concave portion and can slide in the longitudinal direction within the concave portion. The outer peripheral surface of the lens is held in contact with a pair of inclined surfaces.

  In this configuration, part of the outer peripheral surface of the cylindrical lens is held on both slopes of the V-shaped groove, so that the contact area is small and the cylindrical lens can be moved easily and smoothly in the longitudinal direction. In particular, the slopes forming the V-shaped grooves are preferably flat surfaces rather than curved surfaces, and the outer peripheral surfaces of the cylindrical lenses are preferably held in line contact with a pair of slopes. Furthermore, since the convex portion is fitted in the concave portion, it is possible to prevent rotation of the cylindrical lens with a simple configuration.

  A pair of protrusions projecting from both sides of the cylindrical lens are provided, and when the cylindrical lens is inserted into the V-shaped groove, the pair of protrusions are located on the side of the V-shaped groove on the surface of the housing. It is held in a state of being spaced above. According to this configuration, since the cylindrical lens is not held in a suspended state, the cylindrical lens can be supported in line contact with the inclined surface at two locations on the outer peripheral surface as described above. .

  Each of the convex part and the concave part is composed of a narrow part and a wide part which are continuous with each other in the longitudinal direction. The convex part is located at a position where the narrow part corresponds to the narrow part of the concave part, and the wide part is the wide part of the concave part. It can be fitted into the recess only in a state corresponding to the portion. According to this, it is possible to prevent the cylindrical lens from being attached in the wrong direction by a simple configuration.

  The housing may be provided with a restricting portion that contacts the outer peripheral surface of the cylindrical lens above the V-shaped groove and prevents the cylindrical lens from falling off the housing. This restricting portion is easily attached on the upper surface of the housing with a screw or the like, and functions as a safety member for preventing the cylindrical lens from dropping off from the housing even if the attitude of the optical head changes.

  The optical head of the present invention includes a cylindrical lens positioning mechanism having any one of the above-described configurations. Furthermore, the optical recording / reproducing apparatus of the present invention includes this optical head.

  According to the present invention, it is possible to realize prevention of rotation of the cylindrical lens and adjustment of the position in the longitudinal direction with a simple configuration.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the basic structure of the optical head of this embodiment will be described. FIG. 1 is a perspective view showing the internal structure of the optical head of the present embodiment with the cover removed. FIG. 2 shows the optical head shown in FIG. FIG. 3 is an exploded view of the main part for explaining the optical system, and FIG. 4 is a block diagram schematically showing the configuration shown in FIG.

  The optical head 1 has various optical components mounted on a housing 2 made of magnesium or duralumin die-cast. Specifically, as shown in FIG. 1, first and second laser diodes 3 and 4 as optical components on one surface of the housing 2 (surface facing the inside of the housing) and each laser. First and second diffraction gratings (1/2 wavelength plates) 5 and 6 on the optical path of diodes 3 and 4, and first and second lasers transmitted through first and second diffraction gratings 5 and 6 A dichroic prism 8 located at the intersection of the optical paths of the diodes 3 and 4 is attached. Furthermore, on this housing 2, a polarization beam splitter 9 positioned on the optical path of the light emitted from the dichroic prism 8, a front monitor (light receiving element) 17 on the optical path of the light emitted from the polarization beam splitter 9, and a polarization A reflection mirror 10 on the optical path of the light reflected by the beam splitter 9, a sensor lens 15 and a photo detector (light receiving element) 16 positioned on the optical path after the light reflected by the reflection mirror 10 retransmits the polarizing beam splitter 9. Is attached.

  Further, on the other surface of the housing 2 (outer surface of the housing), a laminated body 7 composed of the collimator lens 11, the liquid crystal element 12, and the quarter wavelength plate 13 shown in FIG. Is attached, and the objective lens 14 is attached so that the optical axis of the laminate 7 coincides. As shown in FIG. 1, a circuit board 23 that functions to supply power to the first and second laser diodes 3 and 4 is attached to the other surface of the housing 2.

According to the optical head 1 having such a configuration, the polarization direction of laser light (blue laser light in one example) emitted from the first laser diode 3 is controlled by the first diffraction grating 5 and transmitted through the dichroic prism 8. Then, the polarization beam splitter 9 is reached. On the other hand, a laser beam (for example, a CD laser beam or a DVD laser beam) emitted from a second laser diode 4 (for example, a two-wavelength laser diode capable of selectively emitting a CD laser beam and a DVD laser beam). ) Is controlled in polarization direction by the second diffraction grating 6, reflected by the dichroic prism 8 at an angle of 90 degrees, and reaches the polarization beam splitter 9.

  As described above, the laser light emitted from any of the first and second laser diodes 3 and 4 is guided to the polarization beam splitter 9. Then, the laser light is reflected by the polarization beam splitter 9, further reflected by the reflecting mirror 10 at an angle of 45 degrees, passes through a hole (not shown) provided in the housing 2, and collimator lens 11 and liquid crystal The light is emitted to the outside through the laminate 7 and the objective lens 14 composed of the element 12 and the quarter wavelength plate 13.

  When an optical recording medium 46 (see FIGS. 4 and 8) such as a CD or a DVD is disposed outside the optical head 1, the laser light emitted from the objective lens 14 to the outside as described above. The light hits the optical recording medium 46 and is reflected. The reflected light from the optical recording medium 46 passes through the objective lens 14, the laminate 7, and the hole again, is reflected by the reflecting mirror 10 at an angle of 45 degrees, and reaches the polarizing beam splitter 9. This light passes through the polarization beam splitter 9 and is condensed on the light receiving surface of the photodetector 16 by the sensor lens 15. Then, an output signal output according to the intensity of light received by the photodetector 16 is transmitted to the electrical components on the circuit board 23 and / or an external circuit and analyzed, and the recorded content of the optical recording medium 46 is read.

  When recording on the optical recording medium 46, the light emitted from the objective lens 14 to the outside is written on the recording track of the optical recording medium 46 as described above.

  During the initial adjustment and use of the optical head 1, the laser light passes through the dichroic prism 8 and the polarization beam splitter 9, travels straight and enters the front monitor 17, and the front monitor 17 constantly monitors the intensity of the laser light. . Feedback can be provided to the laser diodes 3 and 4 based on the intensity received by the front monitor 17 so that laser light having a desired intensity is always emitted.

  The present embodiment mainly has a structure for positioning and mounting the sensor lens 15 to the housing 2 in the optical head 1 having the configuration and functions described above.

  As shown in FIGS. 5-7, the V-shaped groove | channel 18 is formed in the housing 2 of this embodiment. The V-shaped groove 18 is composed of a pair of inclined surfaces 18a that are opposed to each other and are inclined so that the interval between them is gradually narrowed. A groove-like recess 19 for fitting is provided along the longitudinal direction of the V-shaped groove 18 at a narrow space between both slopes of the V-shaped groove 18.

  As shown in FIG. 5, the concave portion 19 has a shape in which a narrow portion 19a and a wide portion 19b extend continuously in the longitudinal direction. The width of the narrow width portion 19a of the concave portion 19 is substantially the same as the width of the narrow width portion 20a of the positioning convex portion 20 (see FIG. 3) below the sensor lens 15 described later, and the width of the wide width portion 19b is convex. The width of the wide portion 20b of the portion 20 is substantially the same. The length of the concave portion 19 is longer than the length of the convex portion 20. As shown in FIGS. 1 and 6, a cantilever-shaped restricting portion 21 is provided above the V-shaped groove 18.

  On the other hand, as shown in FIGS. 3, 6, and 7, a convex portion 20 extending along the longitudinal direction is provided at the lower portion of the cylindrical sensor lens 15. As described above, the convex portion 20 has a shape in which the narrow width portion 20a and the wide width portion 20b extend continuously in the longitudinal direction, and matches the concave portion 19 except for the length. A pair of protrusions 22 that protrude from both sides of the sensor lens 15 are provided.

  When the cylindrical sensor lens 15 is inserted into the V-shaped groove 18 of the housing 2, the convex portion 20 is fitted into the concave portion 19, and the outer peripheral surface of the sensor lens 15 is held by a pair of inclined surfaces 18a. The At this time, considering the resistance when the sensor lens 15 is moved in the longitudinal direction, the contact area between the outer peripheral surface of the sensor lens 15 and the pair of inclined surfaces 18a is preferably smaller, and the line contact is more preferable than the surface contact. preferable. In order to achieve line contact between the outer peripheral surface of the sensor lens 15 and the pair of inclined surfaces 18a, each inclined surface 18a is preferably a flat surface rather than a curved surface. Thus, it is preferable that the outer peripheral surface of the arc-shaped sensor lens 15 and the flat inclined surface 18a are in line contact.

  For example, when viewed from the cross-sectional view shown in FIG. 7, the outer peripheral surface of the sensor lens 15 is in point contact with a pair of inclined surfaces 18a at points A and B, respectively. Since the contact points A and B are connected in the longitudinal direction, it is a line contact when viewed three-dimensionally. At this time, the pair of projections 22 projecting from both sides of the sensor lens 15 are held in a state of floating above the V-shaped groove 18 without contacting the surface of the housing 2 and spaced upward. . That is, in the present embodiment, the sensor lens 15 is supported from below by a pair of inclined surfaces 18a, rather than a state in which the lens is suspended in the groove as in Patent Documents 1 and 2.

  The sensor lens 15 is not rotatable in the circumferential direction because the convex portion 20 is fitted in the concave portion 19. Moreover, since the length of the recessed part 19 is longer than the length of the convex part 20, it can slide to a longitudinal direction. The upper part of the sensor lens 15 is held in a non-detachable manner by a cantilever-like restricting portion 21.

  Therefore, when the sensor lens 15 is mounted on the housing 2, first, the sensor lens 15 is inserted into the V-shaped groove 18 so that the convex portion 20 fits into the concave portion 19. At this time, the narrow width portion 20 a of the convex portion 20 is in a position corresponding to the narrow width portion 19 a of the concave portion 19, and the wide width portion 20 b is in a position corresponding to the wide width portion 19 b of the concave portion 19. Then, the sensor lens 15 is moved in the longitudinal direction and adjusted so that the convergence state of the light to the photodetector 16 is good. As described above, since the concave portion 19 is longer in the longitudinal direction than the convex portion 20, the convex portion 20 can move in the longitudinal direction within the concave portion 19. That is, the sensor lens 15 is movable in the longitudinal direction.

  In the present embodiment, since the sensor lens 15 is supported by two lines on the pair of inclined surfaces 18a, the sensor lens 15 is supported in a surface contact manner, and is compared with the conventional technique in which the lens is suspended from above and held. The contact area is small, and the frictional resistance when moving the sensor lens 15 in the longitudinal direction is small. Accordingly, the sensor lens 15 can be translated easily and smoothly. Further, since the convex portion 20 is fitted in the concave portion 19, the sensor lens 15 does not rotate in the circumferential direction. In the present embodiment, the sensor lens 15 can be prevented from rotating and kept in a predetermined posture simply by fitting the convex portions 20 having substantially the same width to the concave portion 19.

  In the present embodiment, the restriction portion 21 is provided in the housing 2. The restricting portion 21 functions as a safety member for preventing the sensor lens 15 from falling off the housing 2 even if the attitude of the optical head changes. The restricting portion 21 also functions as a pressing spring for preventing the sensor lens 15 from moving in the vertical direction (of the V-shaped groove 18) when the position of the sensor lens 15 is adjusted. The restricting portion 21 is easily attached to the upper surface of the housing 2 with screws or the like.

  As shown in FIGS. 6 and 7, the restricting portion (pressing spring) 21 is disposed so as to intersect the longitudinal direction of the sensor lens 15, and is in partial contact with the sensor lens 15. A contact portion of the restricting portion 21 with respect to the sensor lens 12 is configured to protrude in an arc shape toward the sensor lens 15 when viewed from the left side of FIG. Therefore, the apex portion of the arc-shaped protruding portion of the restricting portion 21 is in contact with the sensor lens 15 and strongly pressed. As described above, in the present embodiment, the pair of inclined surfaces 18 a of the V-shaped groove 18 are flat surfaces, and the sensor lens 15 has a cylindrical shape. Therefore, the outer peripheral surface of the sensor lens 15 and the inclined surface of the V-shaped groove 18. 18a is in line contact, and the movement resistance when adjusting the position of the sensor lens 15 is reduced. In addition, the apex portion of the arc-shaped projecting portion of the restricting portion 21 strongly presses only a part of the outer peripheral surface of the sensor lens 15, whereby the outer peripheral surface of the sensor lens 15 and the inclined surface 18 a of the V-shaped groove 18. The length of the contact portion in the longitudinal direction of the sensor lens 15 can be shortened, and the contact relationship between them can be made close to point contact. Accordingly, it is possible to prevent the movement of the sensor lens 15 upward (escape from the V-shaped groove 18) while further reducing the movement resistance when the position of the sensor lens 15 is adjusted.

  By the way, the presser spring of Patent Document 2 is provided so that the lower support arm of the cylindrical lens is pressed against one inner surface (support surface) of the notch portion. It must be loaded in a very small space, and a very complicated installation work is required. However, in the present embodiment, the restricting portion 21 that also functions as a holding spring only needs to perform a simple operation such as screwing using a wide open space above the housing 2 as a working space. It can be installed as easily as the work of attaching a spring.

  Further, in the present embodiment, the convex portion 20 of the sensor lens 15 is configured by the narrow width portion 20a and the wide width portion 20b, and the concave portion 19 is also configured by the corresponding narrow width portion 19a and wide width portion 19b. Yes. Therefore, only when the sensor lens 15 is arranged in the correct orientation, that is, in a direction in which the narrow portion 20a and the narrow portion 19a face each other and the wide portion 20b and the wide portion 19b face each other, the sensor lens 15 is placed in the V-shaped groove. 18 can be inserted. If the sensor lens 15 is in the reverse direction, the wide portion 20 b of the convex portion 20 faces the narrow portion 19 a of the concave portion 19. Since the wide portion 20b is wider than the narrow portion 19a, it cannot be inserted into the narrow portion 19a. Therefore, the convex portion 20 cannot be inserted into the concave portion 19. As a result, the sensor lens 15 is lifted without being inserted into the V-shaped groove 18. As described above, in the present embodiment, by providing the narrow portions 19a and 20a and the wide portions 19b and 20b, it is possible to prevent the sensor lens 15 from being attached in the wrong direction with a very simple configuration.

  As described above, when the position of the sensor lens 15 is adjusted in the longitudinal direction without rotating in the circumferential direction, the pair of protrusions 22 are fixed to the upper surface of the housing 2 using an adhesive (not shown). In addition, the protrusion part 22 of this embodiment is formed in the position of the comparatively upper part of the outer peripheral surface of the housing 2 so that a frictional force may not become large in surface contact with the upper surface of the housing 2. Therefore, the adhesive is injected so as to fill between the protrusion 22 and the upper surface of the housing 2.

  FIG. 8 is a schematic diagram showing the configuration of an optical recording / reproducing apparatus including the above-described optical head 1 of the present invention. This optical recording / reproducing apparatus mainly includes the optical head 1 having the above-described configuration, a spindle motor 42, a controller 43, a laser drive circuit 44, and a lens drive circuit 45.

  The spindle motor 42 rotationally drives an optical disc (optical recording medium) 46 under the control of the controller 43. The controller 43 controls the spindle motor 42, the laser drive circuit 44, and the lens drive circuit 45 based on the photodetector detection signal supplied from the optical head 41. The laser drive circuit 44 generates a laser drive signal for driving the laser diodes 3 and 4 (see FIGS. 1, 3, and 4), which are light sources constituting the optical head 1, under the control of the controller 43. Supply to the head 1. The lens drive circuit 45 generates a lens drive signal for controlling the focusing, tracking, and tilt of the objective lens 14 (see FIGS. 3 and 4) constituting the optical head 1 under the control of the controller 43, and Supply to the head 1.

  The controller 43 includes a focus servo tracking circuit 47, a tracking servo tracking circuit 48, a skew adjustment circuit 49, and a laser control circuit 50. The focus servo follow-up circuit 47 is a focus servo signal for focusing the light beam emitted from the optical head 1 on the information recording surface of the rotating optical disk 46 based on the photodetector detection signal supplied from the optical head 1. Is supplied to the lens driving circuit 45.

  The tracking servo tracking circuit 48 is for tracking the beam spot of the light beam emitted from the optical head 1 with respect to the eccentric signal track of the optical disk 46 based on the photodetector detection signal supplied from the optical head 1. A tracking servo signal is generated and supplied to the lens driving circuit 45. The skew adjustment circuit 49 generates a skew adjustment signal for inclining the objective lens 14 constituting the optical head 1 in the radial direction or the tangential direction based on the photodetector detection signal supplied from the optical head 1 to drive the lens. Supply to circuit 45. The laser control circuit 50 generates an appropriate laser drive signal based on the recording condition setting information recorded on the optical disk 46 extracted from the photodetector detection signal supplied from the optical head 1.

  Such an optical recording / reproducing apparatus including the optical head 1 of the present invention can be mounted with the sensor lens 15 in the correct orientation with a simple configuration, and the position of the sensor lens 15 can be adjusted in the longitudinal direction while preventing rotation. You can easily adjust the distance between.

  In the above example, the optical head 1 provided with two light sources (laser diodes 3 and 4) and the optical recording / reproducing apparatus provided with only one optical head are shown. However, the present invention is not limited to this. Not. The present invention can also be applied to an optical head provided with three or more light sources or a single light source, and an optical recording / reproducing apparatus provided with a plurality of optical heads.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the present embodiment, and there are design changes and the like without departing from the gist of the present invention. Is included in the present invention.

It is a perspective view of the state which removed the cover of the optical head which concerns on one Embodiment of this invention. FIG. 2 is a perspective view of the optical head shown in FIG. 1 viewed from the side opposite to FIG. 1 in a state where an objective lens driving device and a circuit board are removed. It is explanatory drawing which shows the relationship of the optical component of the optical head shown in FIG. FIG. 4 is a schematic diagram showing the relationship of the optical component shown in FIG. 3 in a simplified manner. It is a perspective view of the housing of the optical head shown in FIGS. FIG. 6 is an enlarged perspective view showing a state where the optical head shown in FIG. 5 is mounted on a housing of a sensor lens. It is sectional drawing which expands and shows the attachment state on the housing of the sensor lens of the optical head shown in FIG. It is the schematic which shows the structure of the optical recording / reproducing apparatus containing the optical head of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical head 2 Housing 3 1st laser diode 4 2nd laser diode 5 1st diffraction grating (1/2 wavelength plate)
6 Second diffraction grating (1/2 wavelength plate)
7 Laminate 8 Dichroic Prism 9 Polarizing Beam Splitter 10 Reflecting Mirror 11 Collimator Lens 12 Liquid Crystal Element 13 1/4 Wave Plate 14 Objective Lens 15 Sensor Lens (Cylindrical Lens)
16 Photo detector (light receiving element)
17 Front monitor (light receiving element)
18 V-shaped groove 19 Recessed portion 19a Narrow portion 19b Wide portion 20 Protruding portion 20a Narrow portion 20b Wide portion 21 Restricting portion 22 Protruding portion 23 Circuit board 42 Spindle motor 43 Controller 44 Laser drive circuit 45 Lens drive circuit 46 Optical disc (light) recoding media)
47 Focus servo tracking circuit 48 Tracking servo tracking circuit 49 Skew adjustment circuit 50 Laser control circuit

Claims (7)

In a positioning mechanism for a cylindrical lens, including a housing and a cylindrical lens mounted on the housing,
The housing has a V-shaped groove formed of a pair of inclined surfaces facing each other and gradually inclined so that the interval between the inclined surfaces is gradually narrowed, and a position where the distance between both inclined surfaces of the V-shaped groove is small. And a recess extending along the longitudinal direction of the V-shaped groove,
The cylindrical lens is provided with a convex portion extending along the longitudinal direction,
When the cylindrical lens is inserted into the V-shaped groove, the convex portion fits into the concave portion and is slidable in the longitudinal direction within the concave portion, and an outer peripheral surface of the cylindrical lens is the pair of A cylindrical lens positioning mechanism, wherein the cylindrical lens positioning mechanism is held on a slope.   The cylindrical lens positioning mechanism according to claim 1, wherein an outer peripheral surface of the cylindrical lens is held in line contact with the pair of inclined surfaces. A pair of protrusions protruding from both sides of the cylindrical lens are provided;
When the cylindrical lens is inserted into the V-shaped groove, the pair of protrusions are held on the side of the V-shaped groove at intervals on the surface of the housing.
The positioning mechanism of the cylindrical lens according to claim 1 or 2. Each of the convex part and the concave part consists of a narrow part and a wide part that are continuous with each other in the longitudinal direction,
The convex portion can be fitted into the concave portion only when the narrow width portion is in a position corresponding to the narrow width portion of the concave portion and the wide width portion is in a position corresponding to the wide width portion of the concave portion. Is,
The cylindrical lens positioning mechanism according to any one of claims 1 to 3.   The said housing is provided with the control part which contact | abuts to the outer peripheral surface of the said cylindrical lens above the said V-shaped groove | channel, and prevents dropping of the said cylindrical lens from the said housing. A positioning mechanism for a cylindrical lens according to any one of the above.   An optical head comprising the cylindrical lens positioning mechanism according to claim 1.   An optical recording / reproducing apparatus comprising the optical head according to claim 6.

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