JPH0244535A - Optical head device - Google Patents

Abstract

PURPOSE:To cause a whole optical head device to be compact and thin by deflecting an optical beam from a light source part by a first deflecting means in a direction, in which the optical beam is separated from a recording meidum, and further causing the optical beam to go from a second deflecting means to the recording medium with the deflection angle of an acute angle. CONSTITUTION:In the optical head device to be composed of a light source part 6, a first deflecting means 11, a second deflecting means 12 and an objective lens 8, the light source 6 is arranged so that the optical axis of an optical beam outgoing from the light source part 6 can be dislocated to an optical disk 1 side rather than the reflection point of the second deflecting means 12. Since the proceeding direction of the optical beam 4 to be incident to the second deflecting means is bent 12 by the first deflecting means 11, the position of the optical axis, which is shown by an I-I line, can be moved in the side of the optical disk 1. Since the condition of A3<45 deg. can be obtained for the angle of incidence to the second deflecting means 12, the condition of A1<45 deg. is obtained also for the apex angle of the second deflecting means 12. Thus, a height H1 can be reduced and the whole optical head device can be made compact and thin.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an optical recording medium such as an optical disc, for example, a tn
The present invention relates to an optical head device for recording and reproducing tri.

[Prior Art] Fig. 4 is a configuration diagram (not showing main parts) of an example of a conventional optical head device. In the figure, ( ) indicates an optical disk which is an optical recording medium, and (2) indicates an optical disk facing the optical disk (1). This is an optical head device provided as follows.

(3) is a light beam (4) provided in the optical head device (2).
(5) is a collimator lens provided in the path of the light beam (4) and converts the light beam (4) into parallel light; (6) is a semiconductor laser that emits light from the semiconductor laser (3) and the collimator lens (5); The light source part (7) is a reflecting mirror provided in the path of the light beam (4) to reflect the light beam (4), and the bottom surface of this reflecting mirror (7) is attached to the optical disc (1).
are almost parallel. Also, the angle (apex angle) between the reflective surface and the bottom of this reflective mirror (7) is A1, the angle between the reflective surface and the light beam (4) is A2°, and the normal to the reflective surface and the light beam (4). The angle (incident angle and reflection angle) made with A3,
If the sum of the angle of incidence and the angle of reflection is A, then A + = A
2=A 1-45°, A4=2A, =90°.

(8) is a light beam (4) provided in the optical head device (2).
This objective lens (8) focuses the light onto the optical disk (1), and the position of this objective lens (8) can be adjusted in the focal direction of the optical disk (1) (in the vertical direction in the figure) and in the tracking direction (in the horizontal direction in the figure). It has become.

(110) is the overall height of the optical head device (2), (■t
, ) is the height of the reflecting mirror (7), and (1'+2> is the distance between the reflecting mirror (7) and the objective lens (8), taking into account that the objective lens (8) is adjusted by movement. (H3) is the height of the objective lens (8). (11,) is the distance from the bottom of the reflecting mirror (7) to I in the figure.
- The light beam (4) emitted from the light source section (6) indicated by the I line
), (Hs) is the height from the bottom of the reflecting mirror (7) to the optical axis, which is the central axis of the reflecting mirror (7).
), (US) is the height from the reflection point of the light beam (4) on the reflection mirror (7) to the upper end of the reflection mirror (7), (II7) is the height of the semiconductor laser (3) ) is the height from the lower end of the collimator lens (5) to the optical axis, (11s) is the height from the lower end of the optical head device (2) to the optical axis. Height, ([■1
゜) indicates the height from the optical axis to the upper end of the optical head device (2). Also, in this optical head device 71 (2), 1
．． I, = H, = tr, = 11, /2.

Next, we will discuss the operation. The light beam (4) emitted from the semiconductor laser (3) first passes through the collimator lens (
5), the light is made into parallel light, then reflected vertically upward by a reflecting mirror (7), and then focused as a light spot onto the optical disc (1) by an objective lens (8).

Further, the focused light spot may deviate from a predetermined position on the optical disc (1) due to surface wobbling or eccentricity of the optical disc (1). In such a case, a detection means (not shown) detects the direction and amount of deviation of the optical tube, and a driving device (not shown) detects the direction and amount of deviation of the optical lens (8).
is moved to follow the surface wobbling of the optical disc (1). Thereby, a light spot can be focused on a predetermined position on the optical disc 1), and information can be recorded, reproduced, and erased at the predetermined position.

[Issues to be solved by the inventionffl] In the conventional optical head device (2) configured as described above, H4<[17,I-14<IIs, so the magnitude of If is I -1 or H), and 112. When deciding H2, 1
(The size of 1o is limited by There were problems such as the selection range of internal parts such as 5) became narrower.

This invention was made in order to solve the above-mentioned problems, and provides an optical head device that can be made small and thin as a whole, and that can widen the selection range of internal parts. The purpose is to obtain.

[Means for Solving the Problems] An optical head device according to the present invention includes a first directing means for directing a light beam in a direction away from an optical recording medium;
The second deflection means has an acute deflection angle, and the optical axis of the light beam emitted from the light source section is directed from the deflection point of the second deflection means to the optical recording medium side. The light sources are arranged so as to be offset from each other.

[Function] In this invention, the first deflection means deflects the light beam emitted from the light source section in a direction away from the medium, and the light beam deflected by the first deflection means is , the second deflection means deflects at an acute angle.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing the main parts of an optical head' device according to an embodiment of the present invention, and the same or equivalent parts as in FIG. .

In the figure, (11) is a first deflection means that is provided in the path of the light beam (4) and reflects and deflects the light beam (4) in a direction away from the optical disk (1), and this first deflection means (11) consists of a total reflection mirror.

(12) is a second deflection means consisting of a reflection mirror that further deflects the light beam (4) deflected by the first deflection means (11), and the bottom surface of this second deflection means (12) is attached to the optical disk. It is almost parallel to (1). Further, as in the conventional example, the apex angle of the second deflection means (12) is set to A1,
Let A2 be the angle between the reflecting surface of the deflecting means (12) and the light beam (4), and let A be the incident angle and the reflection angle, A +
-A3 < 45°, A2 n 45°.

Furthermore, if the unidirectional angle, which is the sum of the incident angle and the reflection angle, is A, then A I = A 3 < 45°, and the deflection angle A of the second deflection means (12) is an acute angle. .

(13) is a light source part (6), a first 10-direction means (11)
.

This is an optical head device consisting of a second deflection means (12) and an objective lens (8), and in this optical head device (13), the optical axis of the light beam (4) emitted from the light source section (6) is
A light source section (6) is arranged so as to be shifted toward the optical disk (1) from the reflection point of the deflection means (12).

In such an optical head unit U (13), the traveling direction of the light beam (4) incident on the second deflection means (12) is set to the first direction.
By bending by the deflection means (11) of
The position of the optical axis indicated by the -I line can be moved upward I\ in the figure. As a result, the light source section (6) can be moved to the space above the light source section (6) that would have been wasted in the conventional example, and the space can be used effectively and the angle of 14 degrees can be reduced.

Further, the incident angle of the second deflection means (12)/\ is A 3
< 45°, so the apex angle of the second deflection means (12) also becomes A + < 45°. Therefore, (1) can be made smaller than in the conventional example, and this also makes it possible to make Ho smaller than in the conventional example. The entire optical head device (13) can be made smaller and J-shaped while maintaining the same effective diameter f of the light beam (4).

Furthermore, along with this, H, > 1-17, I-
14 inches and 11 degrees, and the size of H9 is 07 or 1. Therefore, the selection range of components for the semiconductor laser (3) and the collimator lens (4) becomes wider.

In the above embodiment, a total reflection mirror is used as the first deflection means (11), but the first deflection means is not limited to this.

For example, a deflection prism as shown in FIG. 2 may be used as the first deflection means (11), in which case 1fQ
The deflecting prism not only deflects the light beam (4), but also -14 shaping of the light beam (4). Generally, the fact that the incident light and the outgoing light are not perpendicular or parallel is a drawback when beam shaping is performed using one deflection prism, but as described above, the first deflection means (11 ) by using a deflecting prism as
This drawback is positively eliminated.

Furthermore, as shown in FIG. 3, a first deflection means (11) is a deflection prism, and a second deflection means (11) is a reflection mirror.
12) may be used as a deflection reflector (15).

Furthermore, although a reflecting mirror is used as the second deflecting means (12) in the above embodiment, a deflecting prism or the like may also be used.

Furthermore, although the optical disk (1) is shown as the optical recording medium in the above embodiment, it may be an optical head device for other optical recording media such as an optical card.

Further, in the above embodiment, the light source section (6) is made up of a semiconductor laser (3) and a collimator lens (5), but the light source section is not limited to this.

[Effects of the Invention] As explained above, the optical head device of the present invention has the first
and a second deflection means having an acute angle of deflection, and the optical axis of the light beam emitted from the light source section is closer to the deflection point of the second deflection means than the optical recording medium. Since the light source section is arranged so as to be shifted to the side, the internal space is effectively used, the overall size can be made smaller and thinner, and the selection range of internal parts can be widened.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of an optical head device according to an embodiment of the present invention, FIG. 2 is a block diagram showing an embodiment of a pond according to the present invention, and FIG. 3 is a block diagram showing an embodiment of a pond according to the present invention. FIG. 4 is a block diagram showing an example of a conventional optical head device. In the figure, (1) is an optical disk, (4) is a light beam,
(6) is the light source part, (8) is the objective lens, (11) is the first
(12) is a second (-direction means, <13) is an optical head device. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A light source section that emits a light beam, a first deflection means that deflects the light beam emitted from the light source section, and a second deflection means that deflects the light beam deflected by the first deflection means. and an objective lens that focuses the light beam deflected by the second deflection means perpendicularly onto an optical recording medium, such that the optical axis of the light beam emitted from the light source section is aligned with the second deflection direction. The light source section is arranged to be shifted toward the optical recording medium from the deflection point of the means, the first deflecting means deflects the light beam in a direction away from the optical recording medium, and the second deflecting means deflects the light beam in a direction away from the optical recording medium. An optical head device characterized in that the deflection angle of the means is an acute angle.