JP2008135120A - Optical pickup and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide "an optical pickup and its manufacturing method" capable of easily and precisely positioning a fixed lens disposed at an inner bottom of a chassis. <P>SOLUTION: As a lens attachment part 22 prescribing the attachment position of a collimate lens 15 at the inner bottom of the chassis 10, a first positioning wall 22a and a second positioning wall 22b that are a pair of planes facing in a V shape and a third positioning wall 22c along a plane perpendicular to both the positioning walls 22a, 22b are formed by cutting processing. Then, the collimate lens 15 is positioned in a radial direction by the first and second positioning walls 22a, 22b, and the collimate lens 15 is positioned in an optical axis direction by the third positioning wall 22c. When the lens attachment part 22 is formed, the first and second positioning walls 22a, 22b are cut and processed by a flat tip surface 30a of a cylindrical cutting edge 30, and the third positioning wall 22c is cut and processed by a cylindrical surface 30b of the cutting edge 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical pickup for recording / reproducing signals on / from a disc such as a CD (compact disc) or a DVD (digital versatile disc), and a manufacturing method thereof, and more particularly, to a chassis of the optical pickup. The present invention relates to a structure of a lens mounting portion and a cutting method of the lens mounting portion.

  In general, an optical pickup condenses a light beam emitted from a semiconductor laser and converted into a parallel light beam by a collimator lens onto a recording surface of a disk (medium) by an objective lens, and a return light beam from the disk is collected. Signals can be recorded / reproduced by receiving light with a photodetector through an objective lens. The objective lens is attached to a lens holder. The lens holder is movably supported by a holder support portion, and is driven in a focus direction and a tracking direction by an electromagnetic drive device. These semiconductor lasers, photodetectors, collimating lenses, holder support units, electromagnetic drive units, etc. are held by the chassis of the optical pickup, and aluminum die-casting that is lightweight and has excellent heat dissipation characteristics is widely adopted as the chassis. ing. Such an optical pickup is incorporated in an optical disc player (CD player or DVD player) on the set side, and signals are input / output to / from a semiconductor laser, a photodetector, an electromagnetic drive device, and the like via a strip-shaped flexible printed circuit board. It has become so.

  In such an optical pickup, a semiconductor laser and light emitting / receiving means formed by unitizing the semiconductor laser and a light receiving element are mounted on a support plate, and this support plate is fixed to one side of the chassis. In addition, a lens mounting portion that defines a mounting position of a fixed lens such as a collimating lens disposed in the optical path is formed in advance on the inner bottom portion of the chassis by cutting. In other words, in a chassis made of aluminum die cast or the like, it is difficult to realize a part requiring high dimensional accuracy only by die casting. Therefore, the part is cut with a cutting blade after forming the chassis to have a required dimension. It has gained accuracy.

  As such a lens mounting portion requiring high dimensional accuracy, conventionally, a pair of flat portions opposed to each other in a V shape or L shape is formed on the inner bottom portion of the chassis, and a fixed lens or its holder is formed on both flat portions. A positioning structure is known in which the mounting position of the fixed lens is defined by bringing the part into contact (see, for example, Patent Document 1). Each flat surface portion of the lens mounting portion that serves as a receiving surface for positioning is for positioning the fixed lens disposed in the lens mounting portion in the radial direction. If the positional accuracy, smoothness, etc. are increased, the mounting position of the fixed lens can be defined with high accuracy.

As shown in FIG. 8, when this type of lens mounting portion is formed on the inner bottom portion of the chassis, a cutting blade 1 having a conical tip 1a is used and non-parallel (for example, V-shaped) at the inner bottom portion of the chassis 2. A method of cutting a pair of flat portions 3 and 4 facing each other with a conical tip portion 1a is widely adopted. The cutting blade 1 can be rotated at a high speed while controlling the relative position to the chassis 2, and the cutting blade 1 is in a state where the conical tip 1 a is in contact with the flat surface portion 3 or the flat surface portion 4. By moving in a direction orthogonal to the paper surface, each of the flat portions 3 and 4 can be made into a smooth surface inclined at a desired angle at a desired position. The direction orthogonal to the paper surface of FIG. 8 is a direction along the optical axis of the fixed lens positioned by the two flat surface portions 3 and 4.
JP-A-7-37270 (5th page, FIG. 2)

  As described above, by cutting with the conical tip 1a of the cutting blade 1, it is possible to form the pair of flat portions 3 and 4 serving as lens mounting portions on the inner bottom portion of the chassis 2 with high accuracy. The lens mounting portion of this type is not formed with a wall surface that restricts the position of the fixed lens arranged there in the optical axis direction. This is to prevent the wall surface from obstructing the movement of the cutting blade 1 in the optical axis direction. Then, when positioning the fixed lens arranged at the bottom of the chassis in the optical axis direction, a positioning jig with a regulation pin is used, and the fixed lens is pressed against the regulation pin to set the mounting position in the optical axis direction. It was decided.

  However, even when the mounting position of the fixed lens in the optical axis direction is determined with high accuracy by the positioning jig, when the positioning jig is removed from the bottom of the chassis, the restriction pin is attached to the fixed lens or its holder. Since it had to be slid, there was a possibility that a slight positional deviation occurred in the fixed lens. In addition, in order to avoid such a positional shift as much as possible, the work for removing the positioning jig has to be performed very carefully.

  The present invention has been made in view of the actual situation of the prior art, and a first object of the present invention is to provide an optical pickup capable of easily and accurately positioning a fixed lens arranged at the bottom of the chassis. It is in. A second object of the present invention is to provide a method for manufacturing such an optical pickup.

  The optical pickup according to the present invention includes a first positioning wall and a second positioning wall which are a pair of non-parallel opposing planes as lens mounting portions that define the mounting position of the fixed lens at the inner bottom portion of the chassis, Forming a third positioning wall along a plane orthogonal to the first and second positioning walls by cutting, positioning the fixed lens in the radial direction with the first and second positioning walls, The fixed lens is positioned in the optical axis direction by the third positioning wall.

  In the optical pickup manufacturing method according to the present invention, the first positioning wall and the second positioning wall are cut by the flat tip surface of the cylindrical cutting blade, and the third surface is cut by the cylindrical surface of the cutting blade. The positioning wall was cut.

  According to the optical pickup of the present invention, as the lens mounting portion on the inner bottom portion of the chassis, the first and second positioning walls for positioning the fixed lens in the radial direction, and the third for positioning the fixed lens in the optical axis direction. Since the positioning wall is formed by cutting, it is not necessary to perform a complicated operation using a positioning jig when mounting the fixed lens to the lens mounting portion, and positioning of the fixed lens can be performed easily and accurately. Can be done.

  In addition, according to the method of manufacturing an optical pickup of the present invention, the first and second positioning walls are cut with a flat tip surface of a cylindrical cutting blade, and the third positioning wall is formed on the cutting blade. Since the cutting process is performed on the cylindrical surface, the cutting process on the first positioning wall and the second positioning wall and the cutting process on the third positioning wall can be performed simultaneously or continuously. The third positioning wall can be formed with high accuracy using the same cutting blade. Therefore, it is possible to easily and accurately position the fixed lens in the radial direction and the optical axis direction using the first to third positioning walls thus manufactured as receiving surfaces, and a complicated operation using the positioning jig There is no need to do.

  In the present invention, a die-cast metal chassis is provided with a holder support for movably supporting a lens holder with an objective lens attached thereto, an electromagnetic driving means for driving the lens holder, and a semiconductor laser serving as a light source. And a fixed lens disposed in an optical path between the light receiving / emitting unit and the objective lens, and a mounting position of the fixed lens is defined on the inner bottom portion of the chassis. In the optical pickup in which the lens mounting portion is formed by cutting, a first positioning wall and a second positioning wall which are a pair of flat surfaces facing the lens mounting portion in non-parallel (for example, V shape), And a third positioning wall along a plane perpendicular to the first and second positioning walls, and the first and second positioning walls While positioning the fixed lens as receiving face in the radial direction, and constitute the fixed lens as the third receiving face positioning wall so as to position the optical axis direction.

  As described above, in the optical pickup in which the first to third positioning walls are formed by cutting on the inner bottom portion of the chassis as the lens attachment portion, the first fixed lens such as the collimator lens disposed in the lens attachment portion is used. In addition to positioning in the radial direction by the second positioning wall, it can also be positioned in the optical axis direction by the third positioning wall, so there is no need to perform complicated work using a positioning jig when attaching the fixed lens, The fixed lens can be easily and accurately positioned.

  Further, in the present invention, a die-cast metal chassis serves as a light source, a holder support unit that movably supports a lens holder to which an objective lens is attached, an electromagnetic drive unit that drives the lens holder, and a light source. A light receiving / emitting means including a semiconductor laser and a fixed lens disposed in an optical path between the light receiving / emitting means and the objective lens are held, and non-parallel (for example, V-shaped) on the inner bottom portion of the chassis. The first positioning wall and the second positioning wall, which are a pair of planes facing each other, and the third positioning wall along a plane orthogonal to the first and second positioning walls are formed by cutting. The fixed lens can be positioned in the radial direction with the first and second positioning walls as receiving surfaces, and the third positioning wall as receiving surfaces. In the manufacturing process of the optical pickup capable of positioning the fixed lens in the optical axis direction, the first positioning wall and the second positioning wall are cut by the flat tip surface of the cylindrical cutting blade, The third positioning wall is cut by the cylindrical surface of the cutting blade.

  In this way, the first and second positioning walls are cut by the flat tip surface of the cylindrical cutting blade, and the third positioning wall is cut by the cylindrical surface of the cutting blade. Since the manufacturing method of forming the lens mounting portion on the bottom can perform the cutting process on the first positioning wall and the second positioning wall and the cutting process on the third positioning wall simultaneously or continuously. These first to third positioning walls can be formed efficiently and with high accuracy. Therefore, it is possible to easily and accurately position a fixed lens such as a collimating lens in the radial direction and the optical axis direction using the first to third positioning walls thus manufactured as receiving surfaces, and use a positioning jig. There is no need to perform complicated operations.

  In the above manufacturing method, when the chassis has a groove between the first and second positioning walls and the third positioning wall, that is, the first and second positioning walls and the third positioning wall. Are adjacent to each other through the groove, the end of the first positioning wall and the second positioning wall on the side of the third positioning wall can be easily cut, so that the cutting time is shortened. Can be achieved.

  The embodiment will be described with reference to the drawings. FIG. 1 is an external view of the optical pickup according to the embodiment, FIG. 2 is a perspective view of the chassis of the optical pickup, and FIG. 3 is a state in which a collimating lens is attached to the chassis. 4 is an explanatory diagram in which a part of FIG. 3 is omitted, FIG. 5 is a front view corresponding to FIG. 4, and FIG. 6 is an explanatory diagram illustrating a lens mounting portion and a cutting blade of the chassis. .

  The optical pickup shown in FIG. 1 is supported by a chassis 10 formed by die-casting an aluminum alloy, a holder support section and electromagnetic drive means supported on the chassis 10, and movably supported by the holder support section. An objective lens 12 attached to the lens holder 11, a light emitting / receiving unit 13 (see FIG. 3) in which a semiconductor laser as a light source and a light receiving element are unitized, and a flexible printed circuit board (see FIG. 3) connected to an optical disc player on the set side. The collimating lens 15 (see FIG. 3) and a reflecting mirror (not shown) are positioned and fixed on the inner bottom portion of the chassis 10. The holder support portion includes a plurality of conductive wires 16 that elastically support the lens holder 11 and a support member 17 through which each wire 16 is inserted. The electromagnetic driving means is composed of a magnet 8, a yoke 9, and the like, and can drive the objective lens 12 in the focus direction and tracking direction of the disk (medium). Each wire 16 also used for energizing the electromagnetic driving means is electrically connected to the FPC 14. The light emitting / receiving unit 13 is mounted on a support plate 18 fixed to one side of the chassis 10, and the terminal portion of the light emitting / receiving unit 13 is also electrically connected to the FPC 14.

  In this optical pickup, the light beam emitted from the semiconductor laser of the light receiving and emitting unit 13 and converted into a parallel light beam by the collimating lens 15 is fixed to the mirror mounting portion 20 of the chassis 10 at a mounting angle of 45 degrees. The light is reflected by the reflecting mirror and condensed on the recording surface of the disk by the objective lens 12 positioned immediately above the reflecting mirror. Further, the return light beam from the disk is transmitted through the objective lens 12, reflected right by the reflection mirror, and received by the light receiving element of the light receiving / emitting unit 13.

  As shown in FIGS. 2 and 3, the chassis 10 has an opening 21 for projecting the light emitting / receiving unit 13, and an inner bottom portion between the opening 21 and the mirror mounting portion 20. A lens attachment portion 22 for defining the attachment position of the collimating lens 15 attached to the holder portion 19 is formed by cutting. The lens mounting portion 22 has a first positioning wall 22a and a second positioning wall 22b, which are a pair of planes facing each other in a 90 ° V-shape, and the first and second positioning walls 22a and 22b. And the third positioning walls 22c and 22d along planes orthogonal to each other, the collimating lens 15 can be positioned in the radial direction as receiving surfaces of the first and second positioning walls 22a and 22b, and the third positioning wall The collimating lens 15 can be positioned in the optical axis direction using the receiving surfaces 22c and 22d.

  As shown in FIG. 3, the collimating lens 15 is mounted on a holder portion 19, and this holder portion 19 is disposed and fixedly adhered to the lens mounting portion 22 on the inner bottom portion of the chassis 10. The collimating lens 15 needs to be positioned with high accuracy in the optical path between the light emitting / receiving unit 13 projecting from the opening 21 and the reflection mirror attached to the mirror attaching portion 20. The first to third positioning walls 22a to 22d are finished by cutting with a cylindrical cutting blade 30 (see FIGS. 2 and 6) after the chassis 10 is die-cast. The cutting blade 30 can be rotated at a high speed while controlling the position relative to the chassis 10, and the flat front end surface 30a of the cutting blade 30 is brought into contact with the first positioning wall 22a and the second positioning wall 22b. By doing so, each positioning wall 22a, 22b can be formed into a smooth surface inclined at a desired angle at a desired position. Further, the cylindrical surface 30b of the cutting blade 30 is brought into contact with the third positioning wall 22c during the processing of the positioning wall 22a, and the cylindrical surface 30b of the cutting blade 30 is brought into contact with the third positioning wall 22d during the processing of the positioning wall 22b. Thus, the third positioning walls 22c and 22d can be smooth surfaces perpendicular to the first and second positioning walls 22a and 22b, respectively. Therefore, the cutting process for the first positioning wall 22a and the second positioning wall 22b and the cutting process for the third positioning walls 22c and 22d can be performed simultaneously or continuously.

  As shown in FIG. 2, a stepped portion 23 that is concave in the optical axis direction of the collimating lens 15 is die-cast between the third positioning walls 22c and 22d. When the third positioning walls 22c and 22d are cut by changing the tilting direction of 30, a step is generated between the positioning walls 22c and 22d with a slight shift in the position of the cutting blade 30. Can be prevented.

  As described above, in the optical pickup according to the present embodiment, the first to third positioning walls 22a to 22d are formed as the lens mounting portion 22 on the inner bottom portion of the chassis 10 by cutting, and the first and second positioning walls 22a to 22d are formed. Since the collimating lens 15 can be positioned not only in the radial direction by the positioning walls 22a and 22b but also in the optical axis direction by the third positioning walls 22c and 22d, the collimating lens 15 is attached to the lens mounting portion 22. It is not necessary to perform complicated work using the positioning jig. Therefore, the collimating lens 15 can be easily and accurately positioned with respect to the chassis 10, and the reliability can be improved and the assembling cost can be reduced. Note that the pair of third positioning walls 22c and 22d is not necessarily provided, and only one of them may be provided.

  In this embodiment, when forming the lens mounting portion 22 of the chassis 10, the first and second positioning walls 22 a and 22 b are cut by the flat tip surface 30 a of the cylindrical cutting blade 30, Since the method of cutting the third positioning walls 22c and 22d with the cylindrical surface 30b of the cutting blade 30 is adopted, the cutting of the first positioning wall 22a and the third positioning wall 22c, and the second The cutting of the positioning wall 22b and the third positioning wall 22d can be efficiently performed simultaneously or continuously.

  FIG. 7 is a perspective view of a principal part showing a modification of the lens mounting portion 22 of the chassis 10. In the lens mounting portion 22 shown in FIG. 7, a groove portion 22e is provided between the first positioning wall 22a and the third positioning wall 22c, and both positioning walls 22a and 22c are adjacent to each other via the groove portion 22e. It is the composition. Although not shown, a similar groove is also provided between the second positioning wall 22b and the third positioning wall 22d. In this way, a minute curved surface does not remain at the end of the first positioning wall 22a or the second positioning wall 22b on the third positioning walls 22c, 22d side after the cutting process, and the collimating lens 15 The holder portion 19 can be reliably abutted against the third positioning walls 22c and 22d.

  In the above embodiment, the structure of the lens mounting portion 22 for the collimating lens 15 and the cutting method are described. However, the lens mounting portion for other fixed lenses disposed on the inner bottom portion of the chassis 10 is described below. However, it goes without saying that the present invention can be applied.

1 is an external view of an optical pickup according to an embodiment of the present invention. It is a perspective view of the chassis of the optical pickup. It is a perspective view which shows the state which attached the collimating lens to this chassis. It is explanatory drawing which abbreviate | omitted illustration of FIG. FIG. 5 is a front view corresponding to FIG. 4. It is explanatory drawing which shows the lens attachment part and cutting blade of this chassis. It is a principal part perspective view which shows the modification of this lens attaching part. It is explanatory drawing which shows a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Chassis 11 Lens holder 12 Objective lens 13 Light receiving / emitting unit 15 Collimating lens (fixed lens)
16 Wire 17 Support member 19 Holder portion 22 Lens mounting portion 22a First positioning wall 22b Second positioning wall 22c, 22d Third positioning wall 30 Cutting blade 30a Tip surface 30b Cylindrical surface

Claims (4)

A die-cast metal chassis includes a holder support that movably supports a lens holder to which an objective lens is attached, electromagnetic drive means for driving the lens holder, and light receiving and emitting including a semiconductor laser as a light source And a fixed lens disposed in the optical path between the light emitting / receiving unit and the objective lens, and a lens mounting portion for defining a mounting position of the fixed lens on the inner bottom portion of the chassis. In the optical pickup formed by cutting,
A first positioning wall and a second positioning wall, which are a pair of planes facing non-parallel to the lens mounting portion, and a third positioning along a plane orthogonal to the first and second positioning walls And the fixed lens is positioned in the radial direction using the first and second positioning walls as receiving surfaces, and the optical axis of the fixed lens is used as the receiving surface for the third positioning walls. An optical pickup configured to be positioned in a direction.   2. The optical pickup according to claim 1, wherein the fixed lens is a collimating lens that converts light emitted from the semiconductor laser into a parallel light beam. A die-cast metal chassis includes a holder support for movably supporting a lens holder to which an objective lens is attached, electromagnetic driving means for driving the lens holder, and light receiving and emitting including a semiconductor laser serving as a light source. And a fixed lens disposed in an optical path between the light emitting / receiving unit and the objective lens, and a first pair of planes that are non-parallelly opposed to the inner bottom of the chassis. The first and second positioning walls and the third positioning wall along a plane perpendicular to the first and second positioning walls are formed by cutting, and the first and second positioning walls are formed by cutting. The fixed lens can be positioned in the radial direction as a receiving surface of the positioning wall, and the fixed lens can be positioned in the optical axis direction as the receiving surface of the third positioning wall. In the manufacturing process of the possible optical pickup,
The first positioning wall and the second positioning wall are cut by a flat front end surface of a cylindrical cutting blade, and the third positioning wall is cut by a cylindrical surface of the cutting blade. An optical pickup manufacturing method characterized by the above.   4. The method of manufacturing an optical pickup according to claim 3, wherein the chassis has a groove portion between the first and second positioning walls and the third positioning wall.

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