JP2011086320A - Optical pickup device and method for mounting grating to be used for same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device which enables downsizing without using a coil spring, and also to provide a method for mounting a grating to be used for the same. <P>SOLUTION: The method has first to fourth steps of: disposing in a base 108 a grating holder 109 which holds the grating 102; temporarily fixing the grating holder 109 to the base 108 with an adhesive tape 120; rotating the grating 102 in the direction of rotating around an optical axis to adjust the mounting position of the grating 102 while temporarily fixing the grating holder 109 to the base 108; and completely fixing the grating 102 subjected to mounting position adjustment to the base 108. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical pickup device used for recording and reproduction of an optical recording medium such as a CD (Compact Disc) and a DVD (Digital Versatile Disc), and a grating mounting method used therefor.

  An example of an optical pickup device used for recording and reproduction of an optical recording medium such as a CD or DVD will be described. FIG. 5 is a schematic view of an optical system of a conventional optical pickup device, and FIG. 6 is an enlarged sectional view of a light source unit used in the optical pickup device.

  5 and 6, the optical system of the optical pickup device 1 includes a light source unit 4 in which a laser diode 2 and a grating 3 are arranged, and laser light emitted from the light source unit 4 as return light from the optical recording medium 10. A beam splitter 5 for separating, a collimating lens 6 for converting the laser light from the light source unit 4 into parallel light, an objective lens 7 for focusing the parallel light from the collimating lens 6 on the recording surface of the optical recording medium 10, and a sensor A photodetector 9 for receiving the return light from the optical recording medium 10 via the lens 8 is provided.

  The light source unit 4 is attached to a cylindrical housing portion 21 formed on the device frame 20 of the optical pickup device 1, a cylindrical holder 22 inserted coaxially from the one end opening 21 a, and a tip of the cylindrical holder 22. The laser diode 2 is inserted between the grating 3 and the coil spring 23 and is inserted coaxially from the housing opening 21a.

  When the grating 3 is attached to the cylindrical holder 22, the rotational position of the optical axis L with respect to the rotation direction is adjusted. This adjustment is performed by inserting a jig such as an eccentric pin through a through hole 21e opened in the accommodating portion 21 and rotating the cylindrical holder 22 about the optical axis L. When the cylindrical holder 22 is rotated, the state is maintained and temporarily fixed by the pressing force of the coil spring 23 in a compressed state. Then, after adjusting the rotational position of the grating 3, the grating 3 is permanently fixed with an adhesive or the like.

  As prior art document information related to the invention of this application, for example, Patent Document 1 is known.

JP 2000-285494 A

  In the conventional optical pickup device 1, when the rotational position of the grating 3 is adjusted, the rotational position is temporarily fixed by the pressing force of the coil spring 23 and then permanently fixed using an adhesive or the like. For this reason, the coil spring 23 must be used. However, when the optical pickup device 1 is reduced in size, there is a problem that it is difficult to secure a space for arranging the coil spring 23.

  An object of the present invention is to solve the above problems and to provide an optical pickup device that can be miniaturized without using a coil spring and a grating mounting method used therefor.

  In order to achieve the above object, a grating mounting method for an optical pickup device according to the present invention includes a light source, a grating that diffracts light from the light source, a holder that holds the grating, and a base on which the holder is disposed. A grating mounting method for an optical pickup device, comprising: a first step of disposing the holder holding the grating on the base; a second step of temporarily fixing the holder to the base; A third step of adjusting the mounting position of the grating by rotating the grating in the circumferential direction of the optical axis while temporarily fixed to the base, and a second step of permanently fixing the grating having the adjusted mounting position to the base 4 and the second step includes sticking the holder to the base. A method in which a step of temporarily fixed with tape.

  In order to achieve the above object, an optical pickup device according to the present invention includes a light source, a grating that diffracts light from the light source, a holder that holds the grating, and a base on which the holder is disposed. An optical pickup device manufactured using a grating mounting method of the device, wherein the grating mounting method includes a first step of placing the holder holding the grating on the base, and temporarily mounting the holder on the base. A second step of fixing, a third step of adjusting the mounting position of the grating by rotating the grating in the circumferential direction of the optical axis in a state where the holder is temporarily fixed to the base; And a fourth step of permanently fixing the adjusted grating to the base. The second step has a structure in which the step of temporarily fixing an adhesive tape the holder to the base.

  According to the optical pickup device of the present invention and the grating mounting method used therefor, since the holder holding the grating is temporarily fixed to the base with the adhesive tape, there is no need to provide a space for arranging the adhesive tape. That is, it is possible to reduce the size of the optical pickup device.

1 is an exploded perspective view of an optical pickup device according to an embodiment. Enlarged perspective view near the grating of the optical pickup device Enlarged perspective view of the vicinity of the grating of the optical pickup device showing the state before the rotation position is adjusted Enlarged perspective view of the vicinity of the grating of the optical pickup device showing the state at the time of adjusting the rotational position Schematic diagram of optical system of conventional optical pickup device Enlarged sectional view of a light source unit used in the optical pickup device

  Hereinafter, an optical pickup device according to an embodiment and a method of attaching a grating used therein will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view of an optical pickup device according to an embodiment, and FIG. 2 is an enlarged perspective view of the vicinity of a grating of the optical pickup device.

<Overall Configuration of Optical Pickup Device 100>
The overall configuration of the optical pickup device 100 will be described.

  In FIG. 1, an optical pickup device 100 includes a laser diode 101 as a light source that emits laser light, a grating 102 for dividing the laser light, a polarization beam splitter 103 that can emit laser light in any direction depending on the polarization direction, a disk ( (Not shown), a rising mirror 104 for reflecting an optical system arranged in parallel with the recording surface of the disk in a direction perpendicular to the recording surface of the disk, and an objective lens 105 for condensing the laser beam on the recording surface of the disk. The objective lens actuator 106 for controlling the spot position of the laser beam and the detector 107 for detecting the reflected light from the disk are arranged on the base 108.

  As shown in FIG. 2, the grating 102 is held on the grating holder 109 and disposed on the base 108. The grating 102 is held in advance in the grating holder 109 so that the center of the optical axis of the laser beam and the center of the grating 102 coincide with each other.

<Operation of Optical Pickup Device 100>
Next, the operation of the optical pickup device 100 will be described.

  The optical pickup device 100 adjusts the spot position of the laser beam on the disk by driving the objective lens actuator 106 in order to correctly reproduce the information. This adjustment is performed by controlling the objective lens actuator 106 using a three-beam method for detecting a tracking error.

  In this three-beam method, since it is necessary to irradiate three spots on the disk, a grating 102 is disposed in the vicinity of the laser diode 101 to divide the laser light into three. When the position of the grating 102 is shifted, variations in the intensity of the three laser beams and positional shifts occur, and error detection cannot be performed. Therefore, high accuracy is required for attachment.

<Attaching the grating 102>
Next, attachment of the grating 102 will be described.

  3 is an enlarged perspective view in the vicinity of the grating showing a state before adjustment of the rotational position, and FIG. 4 is an enlarged perspective view in the vicinity of the grating showing a state at the time of adjusting the rotational position.

  In FIG. 3, the attachment of the grating 102 is performed in the first to fourth steps.

  In the first step, the grating holder 109 holding the grating 102 is disposed on the base 108.

  In the second step, the grating holder 109 is temporarily fixed to the base 108. This temporary fixing is performed by attaching an adhesive tape 120 to the grating holder 109 and the base 108. The adhesive tape 120 is attached to the base 108 and the grating holder 109 on a surface parallel to the optical axis.

  In the third step, with the grating holder 109 temporarily fixed to the base 108, the grating 102 is rotated in the rotation direction of the optical axis to adjust the mounting position of the grating 102.

  A contact surface parallel to the optical axis of the base 108 and the grating holder 109 is processed into a curved surface centered on the optical axis, and the grating holder 109 is provided with a groove 109a. This groove 109a is for inserting an adjustment tool 110 for rotating the grating 102 in the direction of rotation of the optical axis. The grating holder 109 can be rotated in the rotation direction of the optical axis (in the rotation direction around the optical axis) by partial peeling and elasticity of the adhesive tape 120. Further, by inserting the adjustment tool 110 into the groove 109 a provided in the grating holder 109 and pressing the grating holder 109 against the base 108, the movement in the direction perpendicular to the optical axis can be restricted.

  Specifically, it is as follows. As shown in FIG. 4, the adjustment tool 110 is inserted into the groove 109 a of the grating holder 109. Then, with the grating holder 109 pressed against the base 108, the adjustment tool 110 is moved in the tangential direction of the circle around the optical axis (arrow A in FIG. 4). With this movement, the grating holder 109 can be rotated in the direction of rotation of the optical axis.

  In the fourth step, after the grating holder 109 is rotated to an appropriate rotation position, the adjustment tool 110 is fixed. By fixing the adjustment tool 110, the movement of the grating holder 109 due to the stress of the adhesive tape 120 and its own weight is restricted. Then, the grating holder 109 and the base 108 are permanently fixed. The main fixing is performed by bonding the grating holder 109 and the base 108 with an adhesive.

  As described above, the optical pickup device 100 is manufactured by attaching the grating 102 according to the first to fourth steps.

<Summary of one embodiment>
According to the grating mounting method of the optical pickup device in the present embodiment, since the grating holder 109 holding the grating 102 is temporarily fixed to the base 108 with the adhesive tape 120, there is no need to provide a space for arranging the adhesive tape 120. . That is, since the volume corresponding to the space can be reduced, the degree of freedom in design is improved, and the optical pickup device can be downsized.

  Further, a conventional spring or the like attached for adjusting the position of the grating holder 109 becomes unnecessary, and the number of parts can be reduced, so that the cost can be reduced.

  In particular, as the size is reduced, it is generally difficult to design the pressing force of the spring. If the dimensional accuracy of the component varies by several tens of μm, a new problem that the pressing force is too strong or too weak to adjust the rotation of the grating holder 109 may easily occur. However, according to the present embodiment, such a problem does not occur because a spring or the like is not used.

  The present invention is applicable to an optical pickup device used for recording and reproduction of an optical recording medium.

DESCRIPTION OF SYMBOLS 100 Optical pick-up apparatus 101 Laser diode 102 Grating 103 Polarizing beam splitter 104 Standing mirror 105 Objective lens 106 Objective lens actuator 107 Detector 108 Base 109 Grating holder 109a Groove 110 Adjustment tool 120 Adhesive tape

Claims (4)

A grating mounting method for an optical pickup device comprising: a light source; a grating that diffracts light from the light source; a holder that holds the grating; and a base on which the holder is disposed.
A first step of disposing the holder holding the grating on the base;
A second step of temporarily fixing the holder to the base;
A third step of adjusting the mounting position of the grating by rotating the grating in the circumferential direction of the optical axis in a state where the holder is temporarily fixed to the base;
A fourth step of permanently fixing the grating with the mounting position adjusted to the base;
The second step includes
A grating mounting method for an optical pickup device, wherein the holder is temporarily fixed to the base with an adhesive tape. The second step includes
The grating mounting method for an optical pickup device according to claim 1, wherein the holder is temporarily fixed to the base with the adhesive tape so as to be rotatable only in a circumferential direction of the optical axis of the light. The second step includes
The grating mounting method for an optical pickup device according to claim 1, wherein the holder is temporarily fixed to the base with the adhesive tape on a plane parallel to the optical axis of the light. An optical pickup device manufactured using the grating mounting method for an optical pickup device according to claim 1.

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