JPH02246023A - Optical tape device - Google Patents

Abstract

PURPOSE:To perform the positioning adjustment of a beam spot satisfactorily and with high accuracy by performing the positioning adjustment of the beam spot converged on an optical tape by displacing a relay lens arranged outside a cylinder. CONSTITUTION:A convex lens 10 for beam convergence is arranged in an optical path between a collimator lens 3 and a reflecting prism 4, and the convex lens 10 and an electromagnetic driving device 11 are arranged on a chassis outside the cylinder 6. When focusing deviation occurs in a beam converged on the optical tape 9, the focusing deviation can be corrected by displacing the convex lens 10 in the direction of its optical axis by receiving a signal from a control signal generation circuit 12. Also, when track deviation occurs in the beam converged on the optical tape 9 against a track on the optical tape 9, the convex lens 10 is displaced in a direction intersected orthogonally to the optical axis by receiving the signal from the control signal generation circuit 12, and a converging point is positioned on the track. Thereby, it is possible to easily and with high accuracy perform the positioning adjustment of a convergence spot.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an optical tape device that records and/or reproduces information by converging a beam onto an optical tape that is not wound around a cylinder.

(b) As an example of a conventional optical tape device, for example, Japanese Patent Application Laid-Open No. 62-149
There is one disclosed in Publication No. 036 (G 11 B71085). The configuration of the optical tape device is shown in FIG.

In the figure, (1) is a laser diode, (2) is a half prism, (3) is a collimator lens, (4) is a reflective prism, (5) is an objective lens, (6) is a cylinder, (
7) is the cylinder drive motor, (8) is the 7 oto sensor,
(9) is an optical tape.

In this conventional example, a laser beam emitted from a laser diode (1) passes through a half prism (2) and a collimator lens (3) to become parallel light, and then passes through a reflective beam placed in a cylinder (6). The light is reflected laterally by the prism (4), and further focused by the objective lens (5) and focused onto the optical tape (9).

The beam reflected from the optical tape (9) travels the same optical path as described above and enters the half prism (2), whereupon it is reflected laterally and received by the photosensor (8). Further, the cylinder (6) is rotated at a constant speed by the motor (7), and the optical tape (9) is rotated at a constant speed in the longitudinal direction while being wound diagonally around the outer peripheral surface of the cylinder (6). The optical tape (9) is then obliquely scanned by the focused spot of the laser beam. Thus, information is recorded on the optical tape (9) in a diagonal track shape in the recording mode, and information recorded on the optical tape (9) is read as an output signal of the photosensor (8) in the playback mode. .

By the way, in this optical tape device, since information is recorded and reproduced by concentrating the beam on the optical tape, the focus of the beam must be controlled in the recording and reproduction state, and the beam spot must be controlled during reproduction. Tracking control for recording tracks is also required. Therefore, this optical tape device requires some kind of orcus and tracking adjustment means. As an example of the llI pitching means, Japanese Patent Application Laid-open No. 139340/1983 (G11B7
As disclosed in No. 108), there is a structure in which an objective lens driving device is disposed in a cylinder.

However, in such a configuration, since the objective lens is easily displaceable, vibrations generated in the motor when the cylinder rotates are transmitted to the objective lens, which causes the objective lens to vibrate, thereby disturbing the beam adjustment.

In addition, when the objective lens driving device for focus and tracking adjustment is arranged inside the cylinder as in the conventional example, each error signal created by the output signal from the photosensor arranged outside the cylinder is , it becomes difficult to arrange a supply line for supplying the objective lens drive device inside the cylinder.

(c) Problems to be Solved by the Invention Therefore, the present invention aims to provide a helical scan type optical tape device with a position i of a convergent spot converged on an optical tape.
It is an object of the present invention to provide an optical tape device that can easily and accurately perform ig adjustment.

(d) Means for Solving the Problems In view of the above problems, the present invention provides an optical tape device that records and/or reproduces information by converging a beam onto an optical tape wound around a cylinder. an objective lens fixed to a position near the through hole, a laser light source fixed outside the cylinder, and an optical system that guides the laser light emitted from the light source to the objective lens. and a positional deviation signal generating means for receiving the transmitted beam or reflected beam of the beam converged on the optical tape to generate a positional deviation signal of the beam convergence point, and a positional deviation signal generating means located in the optical path between the light source and the objective lens. , and a relay lens disposed outside the cylinder and displaced in accordance with the positional deviation signal.

(E) Operation The position of the beam spot converged on the optical tape is adjusted by displacing the relay lens in response to a signal from the positional deviation signal generating means.

(f) Example Hereinafter, one embodiment of the present invention will be described using the drawings.

In this embodiment, the same parts as those in FIG. 4 used in the conventional example are given the same reference numerals, and the explanation thereof will be omitted.

In the embodiment shown in FIG. 1, a convex lens (10) for beam convergence is disposed in the optical path between the collimator lens (3) and the reflection prism (4). In addition, the convex lens (10
) is displaced in the optical axis direction and in one direction orthogonal to the optical axis by the electromagnetic drive device (11).

Further, the convex lens (10) and the electromagnetic drive device (11) are arranged on a chassis (not shown) outside the cylinder (6). (12) is a control signal generation circuit whose input line is connected to the output line of photosensor (8) and whose output line is connected to the coil in the electromagnetic drive device (11). ) Optical tape (9)
An electromagnetic drive device @ (
11). As the electromagnetic drive device (11) and the control signal generation circuit (12), an objective lens drive device, a seven-occasion control signal generation circuit, and a tracking control signal generation circuit used in existing compact disc players may be used. applicable.

According to the configuration of this embodiment, when a 7-orcus shift occurs in the beam converged on the optical tape (9), the convex lens (10) receives the signal from the control signal generation circuit (12).
This defocus is corrected by being displaced in the front axis direction. That is, like this, the convex lens (10)
is displaced in the optical axis direction, the incident area of the beam incident on the objective lens (5) changes, and thus the convergence point of the beam converged by the objective lens (5) changes. is changed in a direction perpendicular to the plane of the optical tape (9), thereby positioning this convergence point on the optical tape (9).

Also, the beam converged on the optical tape (9)
9) If the track is out of alignment with the upper track,
When the convex lens (10) is displaced in a direction perpendicular to its optical axis in response to a signal from the control signal generation circuit (12), the optical path of the beam is displaced in a direction perpendicular to the optical axis. Then, the convergence point of the beam converged by the objective lens (5) is displaced in a direction perpendicular to the track, and this convergence point is positioned on the track. The direction of displacement of the convex lens (10) is adjusted in such a way that the convergence point of the beam is displaced in a direction perpendicular to the track. However, the beam converged on the optical tape (9) passes through the control signal generation circuit (
Convex lens (10) that is displaced in response to a signal from 12)
By this action, focus and tracking adjustments are made so that the optical tape is always positioned on the track on the optical tape (9).

FIG. 2 is a diagram showing another embodiment in which a concave lens (13) is used in place of the convex lens (10) of the above embodiment.

In this embodiment as well, by displacing the concave lens (13) in the direction of its tip axis and in the direction orthogonal to the optical axis, the incident area of the beam on the objective lens (9) and the objective lens (
9) Since the optical path of the beam incident on the beam is changed, the beam alignment and tracking adjustment for the seven orifices is performed according to the same principle as in the above embodiment.

FIG. 3 shows still another embodiment of the present invention. In this embodiment, a through hole (15
) is embedded with a sliding contact glass (14), and this sliding contact glass (14) is embedded in the sliding contact glass (
14) is made to protrude outside from the outer peripheral surface of the cylinder (6), so that this tip comes into sliding contact with the optical tape (9). Further, the beam converged by the objective lens (5) is focused on the tip of the sliding glass (14), that is, the sliding glass (14).
) and the optical tape (9), the sliding contact glass (14), the objective lens (15) and the convex lens (10
) is determined. In this embodiment, recording;
In all states of playback, the optical tape (9) is in sliding contact with the sliding glass (14), so the distance between the objective lens (5) and the optical tape is kept constant, and therefore the beam of the optical tape (
9) Out-of-focus on the surface is less likely to occur. Therefore, as in the above embodiment, the convergence point of the beam can be positioned approximately on the surface of the optical tape (9) without adjusting the focus of the beam by displacing the convex lens (10) in the optical axis direction. . Therefore, in this embodiment, the convex lens (10) may be driven only in the tracking control direction by the electromagnetic drive device. However, if the wavelength of the laser beam is shortened with the aim of higher density recording, the depth of focus of the beam will become shallower, so there is a possibility that defocus will occur in this embodiment as well. In such a case,
The convex lens (10) may be changed in seven orcus directions as in the above embodiment, and the beam may be adjusted in seven orifices.

(G) Effects of the Invention As described above, according to the present invention, the position of the beam spot converged on the optical tape is adjusted by displacing the relay lens arranged outside the cylinder. The position of the beam spot can be adjusted well and accurately without being affected by vibrations generated by the cylinder drive motor, and the position shift signal can be used to drive the relay lens without the need for additional complicated wiring. drive unit.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing another embodiment, FIG. 3 is a diagram showing still another embodiment, and FIG. 4 is a diagram showing a conventional example. . (5)...Objective lens, (6)...Cylinder, (8
)...Photo sensor, (9)...Optical tape, (10
) (13)...Convex lens, concave lens (relay lens)
, (12)...Control signal generation circuit (signal generation means).

Claims (1)

[Claims] (1) In an optical tape device that records and/or reproduces information by converging a beam onto an optical tape wound around a cylinder, there is a through hole for beam output formed on the circumferential surface of the cylinder and the vicinity of the through hole. an objective lens fixed at a position, a laser light source fixed outside the cylinder, an optical system that guides the laser light emitted from the light source to the objective lens, and a transmitted beam or reflected beam of the beam focused on the optical tape. a positional deviation signal generating means for receiving the beam and generating a positional deviation signal of the beam convergence point, and a positional deviation signal generating means located in the optical path between the light source and the objective lens and disposed outside the cylinder, and responsive to the positional deviation signal. What is claimed is: 1. An optical tape device comprising: a relay lens that can be displaced by a movement;