JPH10340474A - Light pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup capable of using optimum optical system according to the kinds of optical recording mediums SOLUTION: The optical pickup with a light beam converging means equipped side by side with the first objective lens 6a and the second objective lens 6b respectively corresponding to the two kinds of optical recording mediums different from each other is provided with the first and second light sources 1, 2 each emitting laser beam, the first and second half-mirrors 3, 4 which reflect the laser beams from the first and second light sources 1, 2 and make the beams incident on the first and second objective lenses 6a and 6b and at the same time allow the return beams to transmit each from the first and second objective lenses 6a, 6b, and further the first and second light receiving elements 8, 9 each of which receives the return beam passed through the first and second half mirrors 3, 4. The first and second light sources 1, 2 and the first and second light receiving elements 8, 9 each uses exclusive component corresponding to the optical recording mediums respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical pickup device, and more particularly, to a digital video disk (DVD).
The present invention relates to an optical pickup device capable of recording or reproducing data on or from an optical recording medium, both a compact disk (CD).

[0002]

2. Description of the Related Art Conventionally, an optical pickup device capable of reproducing both DVD and CD optical recording media has been proposed.

FIG. 2 is a perspective view showing an optical pickup device disclosed in Japanese Patent Application Laid-Open No. 8-138261 (hereinafter referred to as prior art 1). As shown in FIG. 2, the optical pickup device 50 includes a light source (not shown), at least two objective lenses 51a and 51b respectively corresponding to at least two types of optical recording media having different protective layer thicknesses, and these objective lenses. There is a selecting means for selecting one of 51a and 51b according to the optical recording medium, and the recording medium is recorded and / or reproduced by irradiating light from a light source onto the recording medium via the objective lens 51a or 51b selected by the selecting means. It is configured to perform.

[0004] Specifically, the selecting means includes an actuator 52
It has. The actuator 52 includes a holder 53 holding the objective lens, a base 55 having a shaft 54 for rotatably supporting the holder 53, and a base 55
And the inner yokes 57a, 5b penetrating from below through the arc-shaped holes 56a, 56b provided in the holder 53.
7b and outer yokes 58a, 58b. Inside the outer yokes 58a, 58b, permanent magnets 59a, 59
b are provided respectively. A tracking coil 61 and a focus coil 62 are provided below the holder 53.
A pole piece 6 is provided on a portion of the holder 53 opposite to the portion where the lens 51a or 51b is provided and the shaft 54.
A permanent magnet 64 having magnetic poles 64a and 64b projecting toward the magnetic pole piece 63 at both ends is provided opposite to the permanent magnet 64. Reference numeral 65 denotes a mirror. In the optical pickup device of the prior art 1, switching between the two objective lenses 51a and 51b is performed by passing a direct current to the tracking coil 61 and rotating the tracking coil 61 so that the magnetic pole piece 63 and the magnetic pole 64a
Alternatively, positioning is performed by a suction force between 64b.

FIG. 3 is a front view showing an optical pickup device disclosed in Japanese Patent Application Laid-Open No. 8-227529 (hereinafter referred to as prior art 2). As shown in FIG. 3, the optical pickup device 70 optically records or reproduces information on an optical recording medium (disk) 71 including a signal recording surface and a protective layer for protecting the signal recording surface. The optical pickup device 70 includes an optical element, at least two types of collimating lenses 72 and 72a, holding means for holding the objective lens 73, supporting means for supporting the holding means,
Switching means. Specifically, the optical element includes a semiconductor laser 74, a diffraction grating 75, a half mirror 76, a laser mirror 77, a concave lens 78, and a photodiode 79. The collimating lenses 72, 72a
The light beams having different shapes are held by the collimating lens holder 81, and convert the light beam emitted from the optical element into a substantially parallel light beam. The switching means is a collimating lens holder 8.
1 and a switching coil provided at one end of the lens holder 81 and applying a suction or repulsion force to a moving direction 82 and a spring for urging the switching coil in the opposite direction.

In the optical pickup device according to the prior art 2, the collimating lenses 72 and 72a are switched by means for switching according to the thickness of the disk 71,
By changing the aberration of the passing beam from 83 to 83a,
The focus is on the signal recording surface of the disk 71 with the least aberration. Reference numeral 84 denotes a beam direction conversion unit.

In each of the optical pickup devices of the prior arts 1 and 2, when the head is not selected, the head 2
Balanced to be located at the neutral point of the two lenses. The selection of the lens corresponding to the optical recording medium is performed by changing the direction of energization of the electromagnet.

[0008]

However, in the prior arts 1 and 2, since the lenses for DVD and CD are separate and juxtaposed, it is necessary to switch these lenses left and right. . Therefore, there is a drawback that it is difficult to apply a tracking servo for fine adjustment of the left and right.
In addition, there is a disadvantage that the left and right balance of the lens holder is deteriorated.

On the other hand, in the optical pickup device of the type in which the optical head is supported by wires, the amount of movement of the lens at the time of switching, that is, the amount of movement of the optical head, is large, and the lens shift characteristic is poor, that is, the lens is left and right. However, when the lens is shaken, the optical axis of the lens is inclined.

Therefore, a general technical problem of the present invention is to
An object of the present invention is to provide an optical pickup device that can use an optimal optical system according to the type of an optical recording medium.

Another special technical problem of the present invention is that, in an optical pickup device used for at least two types of optical recording media, a tracking servo corresponding to each type can be easily applied. An object of the present invention is to provide an optical pickup device.

Another special technical object of the present invention is to improve a lens shift characteristic corresponding to each type in an optical pickup device used for at least two types of optical recording media. It is an object of the present invention to provide an optical pickup device capable of performing the above-described operations.

Still another special technical object of the present invention is to provide an optical pickup device used for at least two types of optical recording media, in which an optical layout (design, etc.) can be easily made. An object of the present invention is to provide a pickup device.

[0014]

According to the present invention, there is provided an optical pickup apparatus provided with a light focusing means in which a first lens and a second lens corresponding to two different types of optical recording media are provided. , Each of which emits a laser beam
And the second light source and the laser beams from the first and second light sources are reflected and incident on the first and second lenses, and the return beams from the first and second lenses are reflected. A light, comprising: first and second half mirrors for transmitting light; and first and second light receiving elements for receiving return beams passing through the first and second half mirrors, respectively. A pickup device is obtained.

According to the present invention, there is provided the optical pickup device, wherein the first and second light sources are provided to face each other.

According to the present invention, in the optical pickup device, the first and second half mirrors may include:
An optical pickup device characterized in that the reflection surfaces are orthogonal to each other is obtained.

Further, according to the present invention, in the optical pickup device, the two kinds of optical recording media are a DVD and a CD.

Further, according to the present invention, in the optical pickup device, the first and second light sources and the first and second light receiving elements use dedicated ones corresponding to the optical recording medium, respectively. Thus, an optical pickup device characterized in that:

[0019]

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

FIG. 1 is a diagram showing a schematic configuration of an optical pickup device according to an embodiment of the present invention. As shown in FIG. 1, the optical pickup device 10 includes a semiconductor laser element (L
D), and a second light source 2 composed of a semiconductor laser element (LD) provided at a position facing the first light source 1. A first half mirror 3 is provided at a laser beam irradiation position of the first light source 1, and a second half mirror 4 similar to the first half mirror is provided at a laser beam irradiation position of one second light source. Is provided.

The laser beams from the first and second light sources 1 and 2 respectively reflected by the first and second half mirrors 3 and 4 are focused on light having different focal lengths held by a lens holder 5. The optical recording medium 7 enters the first and second objective lenses 6a and 6b functioning as means, respectively.
Are converged on the first information recording surface 7a and the second information recording surface 7b, and are reflected by the first and second lenses 6a and 6b.
Each is incident again.

The optical recording medium 7 is composed of a CD or a DVD. The first information recording surface 7a is the position of the information recording surface of the CD, and the second information recording surface 7b is the position of the information recording surface of the DVD. It is.

The return beams from the first lens 6a and the second lens 6b travel straight, respectively, pass through the first and second half mirrors, and are respectively disposed at the focusing positions of the return beams. Respectively incident on the first and second light receiving elements 8 and 9 composed of. Here, the first light source 1 and the first light receiving element 8 are dedicated to a CD, and the second light source 2 and the second light receiving element 9 are dedicated to a DVD.

The lens holder 5 is provided with an actuator having a tracking coil and a focus coil (not shown) and a support member for supporting the lens holder 5 so as to be movable in a horizontal direction and a vertical direction. It is configured to perform.

As described above, according to the embodiment of the present invention, since two optical systems for DVD and CD are provided side by side, dedicated optical systems are used according to the type of optical recording medium. Since it is sufficient to use an optical system, unlike the conventional configuration in which one optical system is also used and each converging lens is moved in parallel, the disadvantages of the conventional technology, such as the difficulty of tracking servo, are eliminated. In addition, tracking servo can be easily and accurately performed.

In the embodiment of the present invention, one optical system is constituted by a combination of a light source, a half mirror, an objective lens, and a light receiving element.
Even when a collimator lens or the like is inserted, the same effect can be obtained according to the present invention. In this case, even if the objective lens is not combined with one holder, a pair of collimator lenses can be combined with one holder as light focusing means,
As in the case of the objective lens, the tracking and focus adjustment may be performed by driving with an actuator.

Further, according to the optical pickup device of the embodiment of the present invention, it is possible to reproduce a disk which can be written only once, such as a CDR (Rewritable CD).

In the embodiment of the present invention, the actuator for driving the holder of the objective lens is
Although the electromagnetic drive system of the tracking and focus coils is used, it is obvious that other drive systems, for example, an electric drive system can be used as long as minute drive can be performed with high accuracy.

[0029]

As described above, according to the present invention, a dedicated light source and a dedicated light receiving element are provided for each, so that an optical pickup can be used which is optimal according to the type of recording medium. An apparatus can be provided.

Further, according to the present invention, it is possible to provide an optical pickup device capable of coping with writing which cannot be performed by the dual-purpose system.

Further, according to the present invention, since the focusing lens is not shifted using one optical system, horizontal movement is unnecessary, and therefore, an optical pickup device capable of performing tracking servo with high accuracy. Can be provided.

Further, according to the present invention, since a dedicated optical system is used according to the type of the optical recording medium, an optical system may be selected according to the optical recording medium, and the shift characteristic of the focusing lens is reduced. An improved pickup device can be provided.

Further, according to the present invention, it is sufficient to use independent optical systems, so that it is possible to provide an optical pickup device which can easily perform an optical layout.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an optical pickup device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an optical pickup device disclosed in the related art 1.

FIG. 3 is a front view showing an optical pickup device disclosed in the related art 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st light source 2 2nd light source 3 1st half mirror 4 2nd half mirror 5 Lens holder 6a 1st objective lens 6b 2nd objective lens 7 Optical recording medium 7a 1st information recording surface 7b 1st 2 information recording surface 8 first light receiving element 9 second light receiving element 10 optical pickup device 50 optical pickup device 51a, 51b objective lens 52 actuator 53 holder 54 shaft 55 base 56a, 56b hole portion 57a, 57b inner yoke 58a, 58b Outer yokes 59a, 59b Permanent magnet 61 Tracking coil 62 Focus coil 63 Magnetic pole piece 64a, 64b Magnetic pole 64 Permanent magnet 65 Mirror 70 Optical pickup device 71 Optical recording medium (disk) 72, 72a Collimating lens 73 Objective lens 74 Semiconductor laser 75 Diffraction Lattice 76 c Fumira 77 laser mirror 78 a concave lens 79 photodiode 81 a collimating lens holder

Claims (5)

[Claims] 1. An optical pickup device comprising a light focusing means having a first lens and a second lens arranged side by side corresponding to two types of optical recording media different from each other, the first and the second emitting a laser beam, respectively. A second light source, and reflecting the laser beams from the first and second light sources,
First and second half mirrors that are incident on the second and third lenses and transmit the return beams from the first and second lenses, respectively, and return beams that have passed through the first and second half mirrors First and second receiving light respectively
An optical pickup device comprising: a light receiving element. 2. The optical pickup device according to claim 1, wherein said first and second light sources are provided to face each other. 3. An optical pickup device according to claim 1, wherein said first and second half mirrors have reflection surfaces orthogonal to each other. 4. The optical pickup device according to claim 1, wherein said two types of optical recording media are a DVD and a CD. 5. The optical pickup device according to claim 1, wherein the first and second light sources and the first and second light receiving elements are dedicated ones corresponding to the optical recording medium, respectively. An optical pickup device, characterized in that: