JPH05258331A - Optical head - Google Patents

Abstract

(57) [Summary] [Purpose] An object is to provide an optical head that is easy to process and assemble, improves the accuracy of process and assembly, reduces costs, and is highly productive. [Structure] A semiconductor laser 2 and a photodetector 5 are fixed to a reference plane A1a of a flat plate-shaped fixing member 1 having a reference plane A1a and a reference plane B1b which are substantially parallel to each other, and a half mirror 3 and a detection element 4 are attached to the reference plane B1b. By fixing or fixing the objective lens driving means 7 including the objective lens 6 and allowing the light flux to pass through the penetrating portion of the fixing member, the fixing member has a very simple and simple shape, and the processing itself is easy and the workability is improved. This results in improvement of processing accuracy. Further, since the fixing member has a simple shape, the optical head itself can be easily assembled, and the cost can be reduced and the mass productivity can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head such as an optical disk device.

[0002]

2. Description of the Related Art It is said that the present age is the information age, and the technological development of high-density and large-capacity memory, which is the core of it, is being actively conducted. In addition to the above-mentioned high density and large capacity, the capabilities required of the memory include high reliability and high speed access, and the optical disk memory is drawing attention as satisfying all of them.

The optical disk memory is for optically recording information on a recording medium, and many developments have been made on a magneto-optical disk capable of erasing recorded information.
The present invention relates to an optical head in an optical disc memory as described above.

The conventional optical head as described above will be described below with reference to the drawings.

FIG. 2 is a schematic plan view of a conventional optical head. FIG. 3 is a side view of a conventional optical head. In FIGS. 2 and 3, 101 is a box-shaped fixing member, 101c.
Is a reference plane C, 101d is a reference plane D, 101e is a reference plane E, 2 is a semiconductor laser, 3 is a half mirror, 4 is a detection element, 5 is a photodetector, 6 is an objective lens, 7 is an objective lens driving means, Reference numeral 8 is an information recording medium, and 9 is a reflection mirror. The operation of the conventional optical head configured as described above will be described below.

The semiconductor laser 2, which is a light source, is fixed to the reference plane C101c of the box-shaped fixing member 101. The emitted light from the semiconductor laser 2 is the reference surface D10 of the box-shaped fixing member 101.
The reflection mirror 9 is transmitted through the half mirror 3 fixed to 1d.
On the information recording medium 8 after being reflected by the objective lens 6.
To form a light spot. The objective lens 6 is fixed to the reference plane E101e of the box-shaped fixing member 101 in the positional relationship with the objective lens driving means 7. The light beam reflected by the information recording medium 8 follows the opposite path and enters the half mirror 3 and is reflected. The reflected light flux enters the detection element 4 fixed to the reference surface D101d. The light beam reflected and refracted by the detection element 4 enters the photodetector 5 fixed to the reference surface C101c of the box-shaped fixing member 101, and detects an information signal, a tracking error signal, and a focus error signal.

[0007]

However, in the above-mentioned structure, the fixing member for fixing the optical system portion including the semiconductor laser 2, the half mirror 3, the detecting element 4, the photodetector 5, etc. is a box. The accuracy of each of the reference plane A 101a and the reference plane 101b for fixing each optical system portion to form the mold shape becomes a problem. The same applies to the reference plane E101e on which the objective lens driving means 7 is fixed. That is, in order to maintain the required processing accuracy, the processing becomes complicated, resulting in an increase in the processing man-hour and the processing time and an increase in the processing cost. In addition, since it has a box shape, it has a problem that the assembling property is deteriorated and the assembling accuracy, time, and cost are deteriorated.

The present invention has been made in view of the above problems, and provides an excellent optical head that simplifies the shape of the fixing member 101, facilitates processing and assembly, and improves processing and assembly accuracy and reduces cost. Is provided.

[0009]

An information recording medium, an objective lens for forming a light spot for recording, reproducing and erasing information on the information recording medium, and a substantially flat plate member substantially parallel to the information recording medium. A first reference surface and a second reference surface, which are two parallel surfaces facing each other, and a penetrating portion extending from the first reference surface to the second reference surface. A fixing member having surfaces facing each other, and an optical system unit fixed to the first reference surface and the second reference surface of the fixing member, the optical system unit being a light source fixed to the first reference surface. A semiconductor laser, a beam splitter that emits light from the semiconductor laser through the penetrating portion, reaches the information recording medium through the objective lens, and reflected light from the information recording medium is reflected by the beam splitter and enters. Fixed to the second reference plane And elements out, and reflected, characterized in that the refracted light and a re-incident through the through part photodetector which is fixed to the first reference plane by sensing element.

The objective lens driving means for driving the objective lens may be fixed to the second reference surface of the substantially plate-shaped fixing member.

Further, independently of the fixed member, the objective lens is provided with a movable optical system part that moves in the radial direction of the information recording medium together with at least one reflection mirror, and the light emitted from the beam splitter is a reflection mirror of the movable optical system part. It can also be characterized in that it is incident on.

[0012]

The present invention has a semiconductor laser,
The fixing member of the optical system composed of the beam splitter, the detection element, the photodetector, etc. is made into a substantially flat plate shape having a penetrating portion, and the light flux passes through the penetrating portion to achieve simplification of the shape of the fixing member. With the simplification, it is possible to improve the processing accuracy, simplify the processing, and reduce the processing man-hour. In addition, by using a substantially flat plate-shaped fixing member, it is possible to easily assemble the optical system part, thereby improving the assemblability and cost reduction, and further improving the assembling accuracy and reliability. ..

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic diagram of a first embodiment of the present invention.

In FIG. 1, reference numeral 1 is a flat plate-shaped fixing member, 1a.
Is a reference plane A, 1b is a reference plane B, 2 is a semiconductor laser, 3 is a half mirror, 4 is a detection element, 5 is a photodetector, 6 is an objective lens, 7 is an objective lens driving means, and 8 is an information recording medium. is there.

The operation of the optical head having the above structure will be described below. Flat plate fixing member 1
The emitted light emitted from the semiconductor laser 2 fixed to the reference plane A1a of the half mirror 3 fixed to the reference plane B1b.
Through the objective lens 6 and is collected on the information recording medium 8. The objective lens 6 is held by the objective lens driving means 7 fixed to the reference plane B1b in order to record, reproduce, and erase signals on the information recording medium 8, and the information recording medium 8 is held.
A light spot is formed at a predetermined position above. The reflected light from the information recording medium 8 passes through the objective lens 6 and the half mirror 3
The light reflected by the half mirror 3 is incident on the detection element 4 fixed to the reference surface B1b. The incident light of the detection element 4 is reflected and refracted by the detection element 4 and then the reference plane A
The information signal, the tracking error signal, and the focus error signal are detected by being incident on the photodetector 5 fixed to 1a. As described above, the present embodiment has a configuration in which all the constituent elements are fixed on the two parallel facing reference surfaces A1a and B1b of the flat plate-shaped fixing member. With this configuration, the fixing member for fixing the semiconductor laser 2, the half mirror 3, the detection element 4, the photodetector 5, and the objective lens driving device 7, which are optical systems, has a complicated shape in the related art and is poor in workability. Although it has been a factor of increasing the cost, the shape becomes extremely simple and simple, and the processing itself is easy, which leads to improvement of the workability and improvement of the processing accuracy. Further, since the fixing member has a simple shape, the optical head itself can be easily assembled, and the cost can be reduced and the mass productivity can be improved.

In this embodiment, the example of the integrated optical head in which the objective lens driving device 7 is fixed to the reference surface B1b of the flat plate-shaped fixing member 1 has been described, but the optical system portion formed on the flat plate-shaped fixing member 1 is described. It is also possible to have a configuration of a separation optical head in which the optical system section including the objective lens driving device is separated.

[0017]

As described above, according to the present invention, an information recording medium, an objective lens for forming a light spot for recording, reproducing, and erasing information on the information recording medium, and an objective lens substantially parallel to the information recording medium. The first reference surface, the second reference surface, and the first reference surface, which are substantially flat plate-shaped members and are two surfaces that are parallel to each other and face each other.
Fixing member having a penetrating portion extending from the reference surface to the second reference surface, the second reference surface being arranged to face the information recording medium, and the first reference surface and the second reference surface of the fixing member. The optical system section is fixed to the optical system section, and the optical system section is a semiconductor laser which is a light source fixed to the first reference surface, and light emitted from the semiconductor laser enters through the penetrating portion and passes through the objective lens. The beam splitter that reaches the information recording medium, the detection element fixed to the second reference surface on which the reflected light from the information recording medium is reflected by the beam splitter and enters, and the light reflected and refracted by the detection element is again generated. Incident through the penetrating part
And a photodetector fixed to the reference surface of the semiconductor laser, a half mirror, a detection element,
The fixing member for fixing the optical system composed of the photodetector, etc. is a substantially flat plate-shaped fixing member, which simplifies the shape of the fixing member and improves the processing accuracy and simplification with the simplification of the shape. It is possible to reduce the number of man-hours and processing steps. In addition, by using a substantially flat plate-shaped fixing member, the assembly of the optical system part can be facilitated, and as a result, assemblability, mass productivity can be improved, cost reduction can be achieved, and assembling accuracy and reliability can also be improved. it can.

The same effect can be obtained also in a structure characterized in that the objective lens driving means for driving the objective lens is fixed to the second reference surface of the substantially flat plate-shaped fixing member.

Further, independently of the fixed member, the objective lens is provided with a movable optical system part which moves in the radial direction of the information recording medium together with at least one reflection mirror, and the light emitted from the beam splitter is a reflection mirror of the movable optical system part. It goes without saying that the same effect can be obtained even if the light is incident on

As described above, the present invention provides an optical head capable of improving the reliability of processing accuracy, reducing the cost of processing and assembling, and improving the mass productivity.

[Brief description of drawings]

FIG. 1 is a schematic view of an optical head of the present invention.

FIG. 2 is a schematic view of a conventional optical head.

FIG. 3 is a side view of a conventional optical head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flat plate-shaped fixing member 1a Reference surface A 1b Reference surface B 101 Box-shaped fixing member 101c Reference surface C 101d Reference surface D 101e Reference surface E 2 Semiconductor laser 3 Half mirror 4 Detection element 5 Photodetector 6 Objective lens 7 Objective lens Driving means 8 Information recording medium 9 Reflecting mirror

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[Procedure amendment]

[Submission date] April 16, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

As described above, the present invention provides an optical head capable of improving the reliability of processing accuracy, reducing the cost of processing and assembling, and improving the mass productivity.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a schematic view of an optical head of the present invention.

FIG. 2 is a schematic view of a conventional optical head.

FIG. 3 is a side view of a conventional optical head.

[Description of Reference Signs] 1 flat plate-shaped fixing member 1a reference surface A 1b reference surface B 101 box-shaped fixing member 101c reference surface C 101d reference surface D 101e reference surface E 2 semiconductor laser 3 half mirror 4 detection element 5 photodetector 6 Objective lens 7 Objective lens driving means 8 Information recording medium 9 Reflecting mirror

Claims (3)

[Claims] 1. An information recording medium, an objective lens for forming a light spot for recording, reproducing and erasing information on the information recording medium, and a substantially flat plate member substantially parallel to the information recording medium. A first reference surface and a second reference surface, which are two front and back surfaces parallel to each other and parallel to each other, have a penetrating portion extending from the first reference surface to the second reference surface, and A flat plate-shaped fixing member arranged such that the second reference surfaces face each other, and an optical system section fixed to the first reference surface and the second reference surface of the flat plate-shaped fixing member, wherein: The system part is a semiconductor laser, which is a light source fixed to the first reference surface, and a beam emitted from the semiconductor laser enters through the penetrating part and reaches the information recording medium through the objective lens. Splitter and reflection from the information recording medium The detection element fixed to the second reference surface on which light is reflected by the beam splitter and enters, and the light reflected and refracted by the detection element again enters through the penetrating portion and enters the first reference surface. An optical head comprising a photodetector fixed to a surface. 2. The optical head according to claim 1, wherein the objective lens driving means for driving the objective lens is fixed to the second reference surface of the substantially plate-shaped fixing member. 3. An objective lens is provided with a movable optical system unit that moves in the radial direction of an information recording medium independently of a fixed member together with at least one reflection mirror, and light emitted from a beam splitter is of the movable optical system unit. The optical head according to claim 1, wherein the optical head is incident on the reflection mirror.