JPS6313143A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To easily execute the positioning of a prism, etc., and to easily assemble the device by extending a polarizing reflection surface and setting it as reference surface. CONSTITUTION:A radiated light projected from an LED 27 is converted into a parallel light by a collimator lens 28. To the parallel light a composite prism 31 inclines at a specified angle nd the prism 31 consists of a circle correction face 50 which cicle-corrects the parallel light, a total reflection face 51 which totally reflects the parallel light transmitted through the correction face 50, a prism 48 having the polarizing reflection face 52 which transmits the parallel light reflected on the reflection face 51 and conducts the reflected light from the record face to a photodetecting element and the prism 49 which conducts the reflected light to the photodetecting element by cooperating with the reflection face 52. And the reflection face 52 is extended and set as the reference face. The reference face like this is set as a reference, so that the positioning of the prism 49, etc., is facilitated. and the assembling can be easily executed.

Description

[Detailed description of the invention] Technical field The present invention relates to an optical information recording/reproducing device.

BACKGROUND ART Information recording media such as video discs and digital audio discs are recorded by irradiating the recording surface with a minute spot light to form pits in a spiral track according to the information signal. It records information signals. Further, when reproducing an information signal recorded in this manner, a spot light is irradiated onto the track and the reflected light or transmitted light is reproduced as the original information signal.

Various devices for reproducing or recording information signals have already been developed. Specifically, the device includes a light emitting element such as a laser diode, a collimator lens that converts the irradiation light emitted by the light emitting element into parallel light, an objective lens that focuses the parallel light on the disk recording surface as a spot light, and the irradiation light. A servo drive mechanism that servo drives the objective lens in the direction of the optical axis of the objective lens and in a direction perpendicular to this in order to accurately focus the light onto a predetermined position on the disk recording surface. It has a light-receiving element and the like for receiving the information signal and obtaining the above-mentioned information signal. In addition, the irradiation pattern of the parallel light emitted through the collimator lens is shaped (changing the elliptical pattern into a circular shape), and the composite light is guided to the objective lens and the reflected light from the disk recording surface is guided to the light receiving element described above. A prism is provided. Of these parts, at least the objective lens and the servo drive mechanism are held by a predetermined holding member, and are moved together with the holding member along the disk recording surface as the disk rotates.

Conventionally, the above-mentioned composite prism has been formed by combining three prisms, for example. The use of such a large number of prisms increases the number of parts, and it is not always easy to combine a large number of prisms with each other with high precision, resulting in an increase in cost. In addition to this problem, there has been a desire to develop an optical information recording/reproducing device that can reproduce or record information with even higher accuracy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and its purpose is to provide an optical information recording/reproducing device that is easy to reduce costs and easy to assemble. Another object of the present invention is to provide an optical information recording and reproducing device that can reproduce or record information with high precision.

The optical information recording/reproducing device according to the present invention includes a compound prism that shapes the irradiation pattern of parallel light emitted through a collimator lens and guides it to an objective lens, and guides reflected light from a recording surface of a recording medium to a light receiving element. , the compound prism includes a circular correction surface that is inclined at a predetermined angle with respect to the parallel light and performs circular correction of the parallel light, a total reflection surface that totally reflects the parallel light that has passed through the circular correction surface, and the total reflection surface. a first prism having a polarized light reflecting surface for transmitting reflected parallel light and guiding reflected light from the recording surface to the light receiving element; a first prism attached to the polarized light reflecting surface and cooperating with the polarized light reflecting surface; and a second prism that guides the reflected light to the light receiving element, and is characterized in that the polarization reflecting surface extends to serve as a reference surface.

A second feature of the optical information recording and reproducing apparatus according to the present invention is that it includes a monitor light receiving element for detecting a part of the irradiated light.

Embodiments Hereinafter, optical information recording and reproducing apparatuses as embodiments of the present invention will be described with reference to the accompanying drawings.

A frame 1 shown in FIGS. 1 to 4 is provided within a housing (not shown) of the optical information recording/reproducing apparatus, and has four leg members 2.3 with respect to the housing.
It is attached via. Note that the frame 1 is made of aluminum or an alloy thereof.

A pair of cylindrical steel support rails 5 and 6 extending in the direction of arrow Y and the opposite direction and spaced apart in the direction of arrow Z and the opposite direction are fixed to this frame 1 at both ends thereof. .

A longitudinal pickup body 7 as a holding member extending in the arrow Z direction and the opposite direction is attached to both support rails 5.
, 6, and is movably supported by both support rails. This pickup body 7 is also made of aluminum or its alloy. Two steel rollers 8 are attached to one side of the pickup body 7 to roll on the support rail 5.

There are also two on the other side of the pickup body 7, a total of 4
Two other steel rollers 9 are mounted at two intervals apart in the direction of movement of the pickup body, and are in contact with the other support rail 6. As is particularly clear from FIG. 4, the pickup body 7 is supported at three points by both support rails 5 and 6 via the aforementioned rollers 8 and 9.

As shown in FIG. 4, a roller 8 provided on one side of the pickup body 7 moves the bin 1 to the pickup body.
1 to the free end of a swing lever 12 which is swingably mounted in the direction of arrow R. Note that the direction of arrow R is perpendicular to the direction of movement of the pickup body (the direction of arrow R and the opposite direction). Further, a spring member 13 is provided as a suppressing means for pressing the roller 8 against the support rail 5. 3 mentioned above
By pressing the roller 8 on the one point side of the point support against the support rail 5 in this way, the rollers 9 on the other two point sides are also pressed against the other support rail 6 by the reaction force. Note that the optical information recording/reproducing device is installed so that the direction of arrow Z is the anti-gravity direction. That is, the roller 8 on the one-point side is always positioned in the anti-gravity direction with respect to the roller 9 on the two-point side. This prevents the spring member 13 for pressing the roller 8 against the support rail 5 from receiving a large weight of the pickup body or the like.

In addition, both the above-mentioned support rails 5.6 and the steel rollers 8,
9, the spring member 13, and peripheral small members related thereto constitute a support means that supports the pickup body 7 so as to be movable along the recording surface of the disk 15, which is a recording medium.

As shown in FIGS. 2 and 4, in frame 1,
A pair of longitudinal magnetic circuits 20 are fixed, each extending along the direction of movement of the pickup body 7 (the direction of arrow Y and the opposite direction thereof) and consisting of a longitudinal magnet 16 and a longitudinal yoke 17, 18 which are engaged with each other. Further, as shown in FIG. 2, a pair of drive coils 21 are attached to the pickup body 7 so that the center axis of the coils is parallel to the direction of movement of the pickup body. The magnetic circuit 20 described above generates a magnetic flux that interlinks with the drive coil, and together with the drive coil constitutes a linear motor as a moving force applying means for applying a moving force to the moving optical system including the pickup body 7.

Note that the linear motor applies a moving force to a portion of the moving optical system including the pickup body 7 that corresponds to a node of primary transverse vibration.

As shown in FIG. 2, a detection coil 22 is wound around the outer periphery of each drive coil 21 described above so that the center axis of the coil is concentric with the center axis of the drive coil. The magnetic flux described above and emitted from the magnetic circuit 20 of the near motor also interlinks with this detection coil 22. These magnetic circuit 20 and detection coil 22 constitute a speed detecting means for detecting the moving speed of the pickup body 7 and controlling the moving speed. That is, the magnetic circuit 20 constituting the linear motor is also used as the magnetic circuit of the speed detecting means.

As is clear from FIG. 2, the aforementioned steel rollers 8 and 9 are arranged on the yoke 17 side of the magnetic circuit 20.

As shown in FIGS. 1, 3, and 4, a flat rectangular parallelepiped-shaped holding member 25 is attached to the rear end of the frame 1. As shown in FIGS. As shown in FIG. 5, this holding member 25 includes a laser diode 27 as a light emitting element,
A collimator lens 28 that converts the irradiation light emitted from the laser diode into parallel light, a condensing lens 29, and a disk 1
A light receiving element 30 for finally receiving the reflected light from the recording surface of No. 5 to obtain an information signal, shapes the irradiation pattern of the parallel light emitted through the collimator lens 28, guides it to an objective lens to be described later, and performs disk recording. A composite prism 31 that guides the reflected light from the surface to the light receiving element 30, and an astigmatism element 32 that imparts astigmatism to the reflected light for the purpose of detecting the focal error of the light beam emitted toward the disk recording surface. is installed. Further, as shown in FIG. 5, on the side of the composite prism 31, there is a monitor light receiving element 34 for detecting a part of the parallel light that is reflected within the composite prism and irradiated to the outside. is located.

FIG. 6 shows the Vl-Vl arrow view with respect to FIG. 5, and as is clear from both figures, the laser diode 2
7 is fitted into a counterbore formed in a rectangular plate-shaped holder 35, and is attached to the holding member 25 via the holder. As shown in FIG. 6, a substantially triangular holding plate 36 is provided to prevent the laser diode 27 from being removed from the holder 35, and
It is fixed to the holder 35 with screws 37.

The rectangular plate-shaped holder 35 described above is movable with respect to the holding member 25 together with the supported laser diode 27 in a plane perpendicular to the optical axis of the laser diode, in this case, in the direction of arrow Y and in the opposite direction. It has become. As a result, the relative positions of the laser diode 27 and the collimator lens 28 within the plane are adjusted, and the parallel light emitted toward the pickup body 7 through the collimator lens 28 is matched with the moving direction of the pickup body. be.

Note that the laser diode 27 and the collimator lens 28
, a composite prism 31, and a holding member 2 that holds them.
5 are collectively referred to as a light source mount.

Furthermore, the light source mount is movable in parallel in the arrow Z direction perpendicular to the optical axis of the parallel light emitted toward the pickup body 7 through the collimator lens 28 and the compound prism 31, and in the opposite direction. Further, the objective lens and its servo drive mechanism, which will be described later, are movable in parallel on the pickup body 7 in the direction of arrow Y and in the opposite direction. As a result, the relative position of the light source mount and the objective lens (described later) in the Y-Z plane is adjusted, and the center axis of the intensity distribution of the parallel light emitted toward the pickup body 7 is aligned with the light of the objective lens (described later). It can be aligned with the axis.

FIG. 7 shows the view from ■--■ in FIG. 5, and as is clear from both figures, the light receiving element 30 is also attached to the holding member 25 via a rectangular plate-shaped holder 39. This holder 39 has a notch 40 that has a clearance in the X direction, the Y direction, and the directions opposite thereto and engages with a screw 41, and is fixed to the holding member 25 by the screw 41. Position adjustment is possible within the clearance range.

FIGS. 8 and 9 show a cross section from ■-■ to FIG. 5 and a cross-section from IX-IX, respectively.
8. The part that holds the condensing lens 29 and the astigmatism cable 32 has a cross-sectional shape perpendicular to the optical path of 43.44 mm with a figure 7 shape.
and 45.

As shown in FIG. 5, the composite prism 31 is formed by joining two prisms, a first prism 48 and a second prism 49. The first prism 48 is a collimator lens 28
A circular correction surface 50 that is inclined at a predetermined angle with respect to the parallel light obtained through the parallel light and performs circular correction of the parallel light (makes the elliptical irradiation pattern of the parallel light circular); a total reflection surface 51 that totally reflects the parallel light reflected by the total reflection surface, and a polarization reflection surface 52 that transmits the parallel light reflected by the total reflection surface and guides the reflected light from the disk recording surface to the light receiving element 30. There is. Further, the second prism 49 is attached to this polarized light reflecting surface 52, and works in cooperation with the polarized light reflecting surface to guide the reflected light from the disk recording surface to the light receiving element 30. The polarization reflecting surface 52 extends widely to serve as a reference surface, and by using the reference surface as a reference, the second prism 49 and the like can be easily positioned.

In addition, as shown in FIG. 5, the collimator lens 28
The angle between the parallel light emitted through and this reference plane is 4
It is 5@. This makes the incident optical axis 54 and the outgoing optical axis 55 parallel to the composite prism 31, making it easy to arrange the laser diode 27 and the light receiving element 30.

As shown in FIG. 3, the pickup body 7 includes:
A total reflection prism 57 is provided as a guide means for bending the optical path of parallel light emitted through the collimator lens 28 and compound prism 31 at right angles. Also,
As shown in FIGS. 1 and 2, the pickup body 7 includes an objective lens 58 for focusing the parallel light that has passed through the total reflection prism 57 onto the recording surface of the disk 15 as a minute spot light; The objective lens includes a holder 59 and a support member 60 (shown in the first figure), and the objective lens is
2) in the direction of arrow F) and in the direction perpendicular to this (direction of arrow T)
The objective lens consists of an objective lens support mechanism that supports the lens movably in the direction, a magnetic circuit consisting of a magnet 62 and a yoke 63, and a coil (not shown) wound around a holder 59 so that the magnetic flux from the magnetic circuit interlinks with the objective lens support mechanism. A driving source is provided that applies a force to move the lens 58 in the two directions. Note that this drive source and the objective lens support mechanism described above are collectively referred to as a servo drive mechanism. That is, the servo drive mechanism drives the objective lens 58 using electromagnetic force.

As shown in FIG. 4, a flexible printed circuit board 65 is provided for supplying drive current to the servo drive mechanism mounted on the pickup body 7. The printed circuit board is bent into a U-shape in its thickness direction, and is disposed within the movement locus of the pickup body 7 so that its thickness direction is parallel to the recording surface of the disk 15.

As shown in FIGS. 1, 3, and 4, a turntable 66 is provided in front of the pickup body 7 and rotates while supporting the disk 15. As shown in FIGS.

Effects of the Invention As detailed above, in the optical recording information reproducing apparatus according to the present invention, the irradiation pattern of the parallel light emitted through the collimator lens (28) is shaped and guided to the objective lens, and from the recording surface of the recording medium. a compound prism (31) that guides the reflected light of the light to the light receiving element, the compound prism has a circular correction surface (50) that is inclined at a predetermined angle with respect to the parallel light and makes circular correction of the parallel light; a total reflection surface (51) that totally reflects the parallel light transmitted through the surface; a polarization reflection surface (52) that transmits the parallel light reflected by the total reflection surface and guides the reflected light from the recording surface to the light receiving element; ), and a second prism (49) that is attached to the polarized light reflecting surface and cooperates with the polarized light reflecting surface to guide the reflected light to the light receiving element.

In this way, since the tube metal prism is formed with only two prisms, the number of parts is small, and it is relatively easy to combine only two prisms with high precision, reducing costs. This makes it easier to achieve.

Further, in the optical information recording/reproducing device according to the present invention, the polarization reflecting surface extends to serve as a reference surface. Therefore, by using the reference plane as a reference, positioning of the second prism and the like becomes easy, and assembly becomes easy.

Furthermore, the optical information recording and reproducing apparatus according to the present invention includes a monitor light receiving element (34) for detecting a portion of the irradiated light. By utilizing this, information can be reproduced or recorded with even higher accuracy.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the internal structure of the main part of the optical information recording/reproducing apparatus according to the present invention, FIGS. The figure is an IV-IV arrow view with respect to FIG. 3, FIG. 5 is a partially detailed view of the internal structure, and FIGS.
1 sectional view, ■-■ arrow view, ■-■ sectional view, and IX-IX sectional view. Explanation of symbols of main parts 5.6...Support rail 7...Pickup body 8.9...Steel roller 13...Spring member 15...・Disk 16...Longitudinal magnet 17.18...Longitudinal yoke 20...Longitudinal magnetic circuit 21...Drive coil 22...Detection coil 25...・Holding member 27... Laser diode - 28... Collimator lens 29... Condensing lens 30... Light receiving element 31... Complex prism 32...Astigmatism element 34...Monitor light receiving element 43.44.45...V-shaped groove 48...
・First prism 49...Second prism 50...Circular correction surface 51...Total reflection surface 52...Polarization reflection surface 58...・Objective lens

Claims (4)

[Claims] (1) A light emitting element, a light receiving element, a collimator lens that converts the irradiated light emitted from the light emitting element into parallel light, an objective lens that focuses the parallel light on the recording surface of a recording medium, and an irradiation pattern of the parallel light. a composite prism configured to guide light to the objective lens and guide reflected light from the recording surface to the light receiving element, the composite prism being inclined at a predetermined angle with respect to the parallel light and forming a circular shape of the parallel light. a circular correction surface that performs correction; a total reflection surface that totally reflects the parallel light that has passed through the circular correction surface; a total reflection surface that transmits the parallel light reflected by the total reflection surface and directs the reflected light from the recording surface to the light receiving element; a first prism having a polarized light reflecting surface for guiding the polarized light; and a second prism attached to the polarized light reflecting surface and cooperating with the polarized light reflecting surface to guide the reflected light to the light receiving element. 1. An optical information recording/reproducing device characterized in that a reference surface is formed by extending. (2) The optical information recording/reproducing apparatus according to claim 1, wherein the reference plane is inclined at 45 degrees with respect to the optical axis of the parallel light emitted from the collimator lens. (3) a light emitting element, a light receiving element, a collimator lens that converts the irradiated light emitted from the light emitting element into parallel light, an objective lens that focuses the parallel light on the recording surface of a recording medium, and an irradiation pattern of the parallel light. a composite prism that is shaped and guides the objective lens and the reflected light from the recording surface to the light receiving element, the composite prism being inclined at a predetermined angle with respect to the parallel light and forming a circular shape of the parallel light. a circular correction surface that performs correction; a total reflection surface that totally reflects the parallel light that has passed through the circular correction surface; and a total reflection surface that transmits the parallel light reflected by the total reflection surface and receives the reflected light from the recording surface through the light receiving element. a first prism having a polarized light reflecting surface for guiding the reflected light to the light receiving element; and a second prism attached to the polarized light reflecting surface and cooperating with the polarized light reflecting surface to guide the reflected light to the light receiving element. An optical information recording and reproducing device, characterized in that the surface extends to serve as a reference surface, and is equipped with a monitor light receiving element for detecting a part of the irradiated light. (4) The optical information recording and reproducing apparatus according to claim 3, wherein the reference plane is inclined at 45 degrees with respect to the optical axis of the parallel light emitted from the collimator lens.