JPH01217734A - Optical head - Google Patents

Abstract

PURPOSE:To obtain a light weight optical head of high resiliency by providing an optical path deflecting means fixed to a head so as to rotate centering the same shaft as the rotating axis of the head in the fixed shaft. CONSTITUTION:Light beams 8 emitted from a fixed optical system 5 pass through a hole 35 in the shaft 10, advances along the turning axis, is further reflected on the reflecting face of the optical path deflecting means 60 fixed to a bearing cover 55 attached to the rotating head 55, thereafter advances in the rotating head 65, is made incident on an objective lens 90 and converged on a disk. In the part of the optical path of a collar 40, the rotating head 65, holes 35 are disposed. In the optical path deflecting means 60, a mirror is bonded to a mirror mounting post made of plastic or the like. In such a way, since the optical path deflecting means is disposed in the shaft so as to have the turning axis at the center, the complete light weight and the high rigidity of the optical head can be attained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to an optical information recording and reproducing method for recording and reproducing information signals;
The present invention relates to an optical head of a recording/reproducing device.

(Prior Art) Various optical heads that move an objective lens in an arc shape are known. is described in JP-A-62-154238 and the like. An example of this is shown in FIG.

However, conventional optical waveguide means have the following problems. That is, since the parallelogram prism is provided on the head in the radial direction from the center of rotation to the objective lens, in the case of rotational driving, the moment of inertia, which can be regarded as a substantial movable mass, becomes large.

Furthermore, since the center of gravity of the head does not coincide with the center of rotation, as described above, it has not been possible to sufficiently reduce the weight and increase the rigidity of the optical head with a configuration using a conventional optical waveguide means.

Therefore, an object of the present invention is to provide a lightweight, highly rigid optical head with a simple configuration.

In the optical head of the present invention, the intended purpose is achieved by providing an optical path deflecting means fixed to the head so as to rotate around the same axis as the rotational axis of the head within the fixed shaft. It is something.

(Function) Since optical path deflection means for guiding light to the objective lens is provided at the axis of the axially rotating optical head, there is no load on inertia, which was a problem in the past.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment of an optical head according to the present invention.

In the figure, 5 represents a fixed optical system, 10 represents a shaft, and 20 represents a substrate. 25 represents an upper bearing, 30 represents a lower bearing, and a collar 40 is provided between the inner rings of the two bearings.

Furthermore, 50 and 55 represent a bearing cover, 60 an optical path deflecting means, 65 a rotary head, 70 a driving coil, 80 a driving magnetic circuit, and 90 an objective lens. The magnetic circuit for the focus actuator is not shown here.

The operation of this embodiment having the configuration described above will be explained as follows. The fixed optical system 5 has a light emitting means and a light receiving means as in the conventional example. The light 8 emitted thereby is the shaft 10
Carefully follow the rotation inside.

In this embodiment, in order to increase the rigidity, the shaft 10 and the substrate 2 are
0 has an integral structure, but it is also possible to cut a screw into one end of the shaft and fix it to the board 20. Further, the inside of the shaft 10 is a hole 35. shaft 1
The light 8 that has traveled inside the rotary head 65 is reflected by the reflective surface of the optical path deflecting means 60 fixed by adhesive or the like to the bearing cover 55 attached to the rotary head 65, and then travels inside the rotary head 65 and reaches the objective lens 90. The light enters and focuses on the disk. Here, the holes 35 also serve as optical paths for the shaft 10, the collar 40, and the rotating head 65. The optical path deflecting means 60 is made of plastic or the like and has a mirror attached to it by adhering it to a pillar.

In the figure, the driving coil 70 and the driving magnetic circuit 80 are shown in a configuration in which they face each other vertically, but the configuration is not limited to this, and a configuration in which the driving magnetic circuits 80 are arranged side by side as shown in FIG. It is applicable.

When configured in this way, the optical path deflecting means 60 is inexpensive, and by providing a sealed structure in the optical path, it is possible to perform smooth operation without dust or the like adhering to the optical path.

FIG. 3 shows a second embodiment of the invention. Third
Although the figure shows a configuration in which the shaft 10 is fixed to the substrate 20 by the bearing cover 50 and the bearing nut 57, the structure is not limited to this, and the shaft 10 and the substrate 20 may be integrally structured as shown in FIG. etc. can also be considered. In the figure, 60 is an optical path deflecting means, and a prism 97 is bonded to the reflecting surface. An example is illustrated in FIG.

With this configuration, when the collimator lens 98 provided in the fixed optical system 5 is tilted due to external vibrations, if the refractive index of the material of the prism 97 is greater than 1, the deflection is corrected and vignetting is prevented. becomes less. FIG. 5 illustrates the effect.

FIG. 6 shows a third embodiment of the invention. In the figure, 99 is a prism provided in the optical path. 6 The prism 99 is fixed to the substrate 20 so that the light 8 emitted from the light source enters the shaft IO from a direction perpendicular to the rotation axis. . In this embodiment, the optical path deflecting means 60 has a structure in which a mirror made of plastic or the like is glued to a pillar, but a structure such as that shown in FIG. 4 is also conceivable.

In this case, the fixed optical system 5 is connected to the substrate 20.
Since the optical head device can be provided on the top, the overall thickness of the optical head device can be reduced.

[Effects of the Invention] As described in detail above, according to the present invention, by providing the optical path deflecting means within the shaft, the substantial movable mass can be reduced compared to the conventional example. Further, since the optical path deflecting means is provided so as to be centered on the rotation axis, it does not affect the vibration of the rotation head in the tracking direction, which is advantageous for increasing the rigidity of the entire optical head device. As a result, high-speed operation can be easily realized using a single-layer optical head that is free from dust and the like.

[Brief explanation of the drawing]

1st rj! I is a cross-sectional view showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view showing an example of a rotating drive means, FIG. 3 is a cross-sectional view showing a second embodiment of the present invention, and FIG. 5 is a perspective view showing an example of an optical path deflection means to which a prism is bonded, and FIG.
A sectional view showing the action of the optical path deflection means shown in the figure, No. 6
The figure is a perspective view showing the third embodiment of the present invention, and FIG. 7 is a sectional view showing the configuration of a conventional example. 5...Fixed optical system 10...Shaft 20...
- Substrate 60... Optical path deflection means 65...
Rotating head 85... Rotating drive means 90... Objective lens 100... Optical waveguide means $7 Figure 3

Claims (3)

[Claims] (1) Light from a light source is focused onto a disk by an objective lens held in a head that rotates around one axis,
An optical information recording and reproducing device for recording and reproducing information signals, characterized by comprising an optical path deflecting means provided at the axis of rotation in order to make the light emitted from the light source enter the objective lens. optical head. (2) The optical head according to claim 1, wherein the optical path deflecting means has a reflective surface, and the reflective surface is provided with a mirror. (3) The optical head according to claim 1, wherein the optical path deflecting means uses a prism.