JPS62143233A - Optical signal pickup device - Google Patents

Abstract

PURPOSE:To facilitate the angle adjustment of a diffraction grating by forming a projection to a cylinder face of a cylindrical holder holding the diffraction grating so as to form an engaged rugged part relatively to the face of the projection orthogonal to the optical axis passing through the diffraction grating and the opposed with a screw driver in press contact with the projected face. CONSTITUTION:The cylindrical holder 3 holding the diffraction grating forms the engaged rugged part with a screw driver on the face orthogonal to the optical axis of the projection from the cylinder face. In adjusting the angle of the diffraction grating 2, a screw drive 9 is inserted to the disc face from the vertical direction and an eccentric pin 11 provided to the tip of the screw driver as the projection is engaged with a slot 13. In turning the screw driver 9, the cylindrical holder 3 is turned around the optical axis by the operation of the eccentric pin 11 to adjust the minute angle of the diffraction grating 2 thereby bringing the sensitivity of the tracking control into the best state.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical signal pickup device, and particularly to an optical signal pickup device suitable for adjusting the positional relationship between a light spot and a track on a disk to an optimal positional relationship. This invention relates to a pickup device.

[Prior Art] Fig. 3 is a perspective view (not showing) of a conventional optical signal pickup device. In the figure, (1) (a semiconductor laser as a light source), (2) a diffraction grating, (2>
is fixed to a rotatable cylindrical holder (3). (
4) is a half prism, (5) is an objective lens, (6) is a disk, (7) is a magnifying lens, and (8) is a photodetector.

Next, the operation will be explained. After the light emitted from the semiconductor laser (1) enters the diffraction grating (2), it is split into multiple diffracted lights of λ, of which three diffracted lights, the straight forward light and the ±1st-order light, are used. The three diffracted lights are half prisms (4)
The light passes through the lens, is focused on the disk (6) by the objective lens (5), and is reflected on the surface of the disk (6) by a diagonal of q. The direction is changed by the half prism (4), and the magnifying L lens (7) is used. After that, the light is focused on the light saving device (8).

The above three diffracted lights are J, Uni, and Disk (shown in Figure 4).
6) Above, the light is focused at an angle to the hit row B1,
The 0th order diffracted light of the anti-GJ light enters the light receiving elements 81 to B4 of the photodetector (8) as shown in FIG. 5, and the ±1st order diffracted light enters the light receiving elements A1 and A2 in the figure. Q'zuru.

The 0th-order diffracted light is used as a digital information signal and a focusing error signal, and the ±1st-order light is used as a difference signal (IAl-IA
2) becomes a tracking error signal, and tracking control is performed by adjusting the optical system so that this becomes zero.

Tracking control (
The shade will be good. For this purpose, the diffraction grating (2) was fixed to a rotatable cylindrical holder (3) as shown in the figure, and a grating was formed on the cylindrical surface of this cylindrical holder (3) parallel to the optical axis. 4'
i (10) is engaged with the eccentric pin (11) provided at the tip of the driver (9), and the cylindrical holder (3) is rotated by the rotation of the driver (9) to perform minute angle adjustments.
Optimize tracking control sensitivity.

[Problems to be Solved by the Invention] Since the conventional optical signal pickup device is constructed as described above, the eccentric pin (11) of the driver (9) relative to the groove (10) of the cylindrical holder (3) ) is inserted in the direction of
The direction is parallel to the surface of the disc (6), and there are problems in that the angle of the diffraction grating cannot be rotated or adjusted after the optical signal pickup device is installed in the player chassis.

This invention was made in order to solve the above-mentioned problems, and provides an optical machine signal pickup device that can easily adjust the angle of the diffraction grating even after being incorporated into the player chassis. The purpose is to

[Means for Solving the Problems 1] The optical signal pickup device according to the present invention has a protrusion formed on the cylindrical surface of a cylindrical holder that holds a diffraction cap, and the protrusion perpendicular to the optical axis that includes the diffraction grating. Engaging uneven portions are formed relative to the face of the driver and the face facing the driver that comes into contact with the slope.

[Embodiment 1 Row 1 The cylindrical holder that holds and covers the diffraction grating in 45 of the present invention has an uneven portion for engaging with the driver on the surface perpendicular to the light 1111 of the protruding portion from the cylindrical surface, so that the optical Even after the signal pickup device is assembled into the player chassis, the driver can be engaged with and disengaged from the projection 1 from below the brake A2 perpendicular to the disc surface, making it possible to easily adjust the angle of the diffraction cap.

[Embodiment 1 of the Invention Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1st
In the figure, the same parts as in FIG. 3 are given the same reference numerals. (12> is a protrusion formed on the cylindrical surface of the cylindrical holder (3), and (13) is formed on the surface of the protrusion perpendicular to the optical axis that breaks the diffraction grating in the radial direction centered on the optical axis. The four parts are made in the groove C.

The method of converging a light spot on the disk (6) and converging the repulsed light from the disk on the photodetector (8) is the same as in the conventional apparatus shown in FIG.

To adjust the angle of the diffraction grating (2), insert the driver (9) from a direction perpendicular to the disk surface and fully engage the eccentric pin (11) as a convex portion provided at the tip of the driver (13). . Then, when the driver (9) is rotated, the cylindrical holder (3) is rotated around the optical axis by the action of the eccentric pin 11), and the fine angle adjustment of the diffraction grating (2) is carried out to control the sensitivity of the tracking control. is the best condition.

FIG. 2 shows another embodiment of the invention, in which the protrusion (
A pin (14) is provided protruding from a surface perpendicular to the optical axis of the driver (9), and a pivoting groove (1) is provided on the driver (9) to engage with the pin (14).
5>@82 digits. The same effect as the above embodiment is achieved.

[Effect of the invention 1 As described above, the present invention (according to this invention) provides a protrusion on the cylindrical surface of a cylindrical holster for fixing a diffraction grating, and the protrusion receives both the optical axis of the diffraction grating. Engaging uneven portions are provided on the opposing surface of the drive bar that contacts the slope and the surface of the drive bar, so that the driver for adjusting the rotation angle can be mounted from the direction of the optical axis perpendicular to the disk surface. can be inserted into the device,
Even after the optical signal pickup device is installed in the player chassis, the angle of the diffraction grating can be easily adjusted from the bottom of the player V.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an optical signal pickup device according to one embodiment of the invention, FIG. 2 is a perspective view showing an optical signal pickup device according to another embodiment of the invention, and FIG.
The figure is a perspective view of a conventional optical signal pickup device.
The figure shows the principle of the three-beam tracking control system for optical pickup, and FIG. 5 is a front view of the photodetector. (1) is a light source (semiconductor (this laser); (2) G; 1.
Diffraction (6 elements, (3) is a cylindrical Holter, (4) is a half beam nozzle, (5) f1 objective lens, (6) 1 is a disk, (8) is an optical detector, (0) is Driver, (1
1) is an eccentric bottle, (12) is a protruding part, and (13) is a four part (
iI! l11), (14) are bottles, (11u) are four parts (
conversion groove),. In addition, in the figures, the same reference numerals and ) indicate corresponding parts. Agent Patent attorney Masuo N-Masu (2 people) Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Voluntary writing of procedural amendments)

Claims (3)

[Claims] (1) A diffraction grating that divides the light emitted from the light source into a plurality of diffracted lights, a rotatable cylindrical holder to which the diffraction grating is fixed, an objective lens that focuses the diffracted light onto a disk, and the disc In an optical signal pickup device having a half prism that focuses reflected light from above onto a photodetector, a protrusion is formed on the cylindrical surface of the cylindrical holder,
An optical signal pickup device characterized in that an engagement uneven portion is formed relative to a surface of the protrusion that is perpendicular to the optical axis passing through the diffraction grating and a surface facing the driver that comes into contact with the surface. (2) A concave portion is formed in the surface of the protruding portion orthogonal to the optical axis passing through the diffraction grating, with which the convex portion of the driver tip engages in the radial direction with the optical axis as the center.
The optical signal pickup device according to item 1). (3) An optical signal pickup according to claim (1), characterized in that a convex portion that engages with a concave portion at the tip of the driver is formed on the surface of the protruding portion perpendicular to the optical axis passing through the diffraction grating. Device.