JPH11120601A - Optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the aberration correcting mechanism of a laser beam a simple structure and also to enable it to be easily manufactured by integrally unitizing a total reflection mirror and an astigmatism generating means. SOLUTION: A total reflection mirror part 27 is formed by integrally unitizing a total reflection mirror 28 in which a reflection surface which is inclined at 45 degrees in a beam incident angle direction is formed and an astigmatism generating means such as a cylindrical lens for correcting the aberration of a laser beam 26 with holders 29, 30. Recessing parts into which the total reflection mirror 28 and the lens 26 are to be inserted are formed in the holders 29, 30 and they are held while being inserted into the recessing parts. Then, the lens 26 is provided in between the total reflection mirror 28 and a laser hologram unit 25. Since the total reflection mirror and the lens 26 are integrally unitized with the holders 29, 30 in this way, the adjusting and the assembling of an optical pickup 10 in which the number of components is reduced are made easy to reduce the number of processes of the assembly and the adjustment. Moreover, since the mirror 28 and the lens 26 are unitized, the quality and the stability of the pickup 10 are enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam emitted from a light source when a recording signal of an optical disk is read and converged by an objective lens to a laser spot of about 1 .mu.m on the information surface of the optical disk. To an optical system for guiding the light to a photodetector.

[0002]

2. Description of the Related Art In an optical disk player using an optical disk as a recording medium, an optical pickup is used as means for reading and reproducing information signals recorded on the optical disk. The optical pickup condenses a laser beam emitted from a laser light source through an objective lens as a beam spot (having a diameter of about 1 μm) on a pit row, which is a minute unevenness formed on a signal recording surface of an optical disk, and The information signal is read and reproduced by detecting the state of the reflected beam reflected from the pit row by a photodetector.

When a laser beam is focused on the pit row of the optical disk as a beam spot via an objective lens, if there is unnecessary aberration in the laser beam, a noise component is superimposed on an information signal to be read and reproduced. As a result, the reproduction characteristics may be degraded, or the reading and reproduction of the information signal may become impossible depending on the degree. Therefore, an optical pickup used in an optical disk player or an optical recording / reproducing device needs a function of correcting such laser beam aberration, and the conventional optical pickup performs the following aberration correction. ing. For example, in order to correct the astigmatism of the LD, the cover glass of the LD is inclined and corrected, or the astigmatism generated in the objective lens is used. The astigmatism is corrected by tilting the flat plate.

[0004]

However, in the above-described astigmatism correction of the optical pickup, the correction performed by obliquely tilting the cover glass optical axis of the LD to correct the astigmatism of the LD is as follows. Basically, since a countermeasure is made with one parallel flat plate, generation of a frame and beam shift occur. In the correction using the astigmatism of the objective lens, in addition to the fact that the variation of the astigmatism is basically very large, it is attempted to generate the astigmatism with a lens that does not originally generate only the astigmatism. Then, a frame is generated, and if the lens is tilt-adjusted to correct the frame, astigmatism will diverge, and the effect cannot be expected. In addition, in the correction in which the parallel plate is inclined during the diverging light of the LD, the number of components for fixing the parallel plate increases, so that the member cost increases, the assembly man-hour increases, and the adjustment man-hour increases. There's a problem.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to realize an aberration correction function in an optical pickup with a simple structure and to be easily manufactured.

[0006]

According to the present invention, there is provided a light emitting section for emitting a laser beam and a light receiving section for receiving a reflected laser beam having recorded information converged on an information recording surface of an optical disk. A light-emitting and light-receiving unit comprising: a laser beam emitted from the light-emitting and light-receiving unit and a laser beam reflected from the optical disc; a total reflection mirror for reflecting the laser beam reflected from the optical disc; An objective lens that converges on a recording surface; and an astigmatism generation unit that corrects astigmatism caused by the light emitting and receiving unit and the objective lens. The total reflection mirror and the astigmatism generation unit are integrated into a unit. It is characterized by being constituted.

Further, the astigmatism generating means is provided between the light emitting and receiving unit and the total reflection mirror. Further, the astigmatism generating means is provided between the objective lens and the total reflection mirror. Further, the astigmatism generating means is provided both between the light emitting and receiving unit and the total reflection mirror and between the total reflection mirror and the objective lens.

Further, the astigmatism generating means is constituted by one parallel flat plate. Also,
The astigmatism generating means is integrally formed by closely adhering to the reflection surface of the total reflection mirror, and the total reflection mirror has an astigmatism correction function.

Also, a light emitting / receiving unit comprising a light emitting unit for laser light and a light receiving unit for receiving reflected laser light having recorded information converged on the information recording surface of the optical disk, and emitted from the light emitting / receiving unit. A total reflection mirror (1) for reflecting the laser light and the laser light reflected from the optical disc; and a total reflection mirror (2) for reflecting the light reflected from the total reflection mirror (1) and the laser light reflected from the optical disc. ), An objective lens for converging the laser beam reflected by the total reflection mirror (2) on the information recording surface of the optical disk, and the light emitting / receiving unit side of the total reflection mirror (1) and the total reflection mirror (2). A) astigmatism generating means using a light transmitting member for correcting astigmatism of convergent or divergent light on the objective lens side, wherein the total reflection mirror (1) and the A total reflection mirror (2) and the astigmatism generation means is characterized in by comprising a unit integrally formed, respectively.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. FIGS. 1A and 1B are schematic structural views showing a main part of an optical pickup according to a first embodiment of the present invention, wherein FIG. 1A is a front view (only the holder is cross-sectional in the vertical direction), and FIG. Cross section).

Reference numeral 10 denotes a main part of the optical pickup 10, which comprises a movable part 20, a suspension wire 22, a damper / yoke part 23, a substrate, a laser hologram unit (corresponding to a light emitting and receiving unit) 25, a total reflection mirror part 27, and the like. Have been. The movable section 20 includes an objective lens 21, a lens holder, an adjustment coil in a focus (up / down) direction, an adjustment coil in a tracking (left / right) direction (all are not shown), and the like. On the side of the movable part 20, four suspension wires 22 of two extremely small elastic bodies (for example, beryllium copper, phosphor bronze, stainless steel for springs, etc.) are fixed at the upper and lower sides, respectively. The other ends of 22 are respectively soldered and fixed to the lands of the substrate. The board is
Since the movable portion 20 including the objective lens 21 is fixed to the substrate support portion (not shown),
Elastically supported. Then, a portion of the upper and lower suspension wires 22 close to the substrate is formed with a damper portion fixed with an elastic resin material, for example, a silicone resin or the like.
The shape and material of the movable portion 20 are selected so as to reduce the overall weight of the movable portion 20 in order to improve the followability and prevent unnecessary resonance (pitching, rolling, yawing, etc.).

An objective lens 21 focuses a laser beam emitted from a laser light source on a signal recording surface of the optical disk 12, and is held by a lens holder. The lens holder is a member that holds the objective lens 15, the adjustment coil in the focus direction, the adjustment coil in the tracking direction, and the like, and is formed by molding using a resin material. In the laser hologram unit 25, a semiconductor laser chip, a photodiode for signal detection, a photodiode for monitoring, a hologram, and the like are contained in the same package and are unitized. The laser hologram unit 25 emits a laser beam from the semiconductor laser chip, detects a reflected beam reflected from the pit array on the signal recording surface of the optical disc 12 and returns with a signal detection photodiode, and converts the reflected beam into an electric signal. Taken out.

The total reflection mirror section 27 includes a total reflection mirror 28 having a reflection surface inclined at 45 degrees with respect to the beam incident angle direction and astigmatism generating means (for example, a cylindrical lens 26) for correcting aberration of the laser beam. And holder 2
Units 9 and 30 are integrated. Holder 2
The two parts 9 and 30 are formed with recesses into which the total reflection mirror 28 and the cylindrical lens 26 are inserted, and hold each of them in between. Note that the cylindrical lens 26 of this embodiment is installed between the total reflection mirror 28 and the laser hologram unit 25.

Next, the operation of the optical system of the optical pickup 10 will be described. The laser beam emitted from the semiconductor laser chip in the laser hologram unit 25 passes through the hologram, the aberration of the laser beam is corrected by the cylindrical lens 26, and the laser beam is reflected by the total reflection mirror in the right angle direction (toward the objective lens 21). Then, the reflected laser beam is converged by the objective lens 21 into a beam spot having a diameter of about 1 μm, and is condensed on a pit row which is a minute unevenness formed on the signal recording surface of the optical disc 12. The focused laser beam is reflected by the pit row, becomes a laser beam having a signal, and returns to the laser hologram unit 25 through the same optical path. Then, the returned laser beam is bent in a predetermined direction by the hologram, reaches a detection photodiode, is converted into an electric signal, and is taken out.

As described above, according to this embodiment, the total reflection mirror 28 and the cylindrical lens 26 for correcting the aberration of the laser beam are unitized integrally by the holders 29 and 30, so that the number of parts is reduced. The assembly and adjustment of the optical pickup 10 is facilitated, and the man-hour for assembly and adjustment is reduced. Further, since the total reflection mirror 28 and the cylindrical lens 26 are unitized, the quality of the optical pickup 10 can be stably improved.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup 10 according to a second embodiment of the present invention. The second embodiment is substantially the same as the first embodiment except for the difference between the total reflection mirror and the astigmatism generating means of the first embodiment. Are denoted by the same reference numerals and description thereof is omitted.

Reference numeral 33 denotes a total reflection mirror unit, which is a parallel reflection plate (non-reflection mirror) having a total reflection mirror 28 having a reflection surface inclined at 45 degrees to the beam incident angle direction and a light transmitting member for correcting laser beam aberration. 34, 35)
Are unitized integrally by holders 36 and 37. The two components of the holders 36 and 37 include a total reflection mirror 2
A concave portion is formed in which the parallel plate 8 and the parallel flat plates 34 and 35 are inserted. The parallel flat plates 34 and 35 of this embodiment are provided between the total reflection mirror 28 and the laser hologram unit 25. The number of the parallel plates 34 and 35 may be increased or decreased as necessary.

Next, the operation of the optical system of the optical pickup 10 will be described. A laser beam emitted from a semiconductor laser chip in the laser hologram unit 25 passes through the hologram, the aberration of the laser beam is corrected by the parallel plates 34 and 35, and the laser beam is reflected in a right angle direction (toward the objective lens 21) by the total reflection mirror. . The reflected laser beam is converged by the objective lens 21 into a beam spot having a diameter of about 1 μm, and is focused on a pit row formed on the signal recording surface of the optical disc 12. The focused laser beam is reflected by the pit row, becomes a laser beam having a signal, and returns to the laser hologram unit 25 through the same optical path.
Then, the returned laser beam is bent in a predetermined direction by the hologram, reaches a detection photodiode, is converted into an electric signal, and is taken out.

As described above, also in this embodiment,
As in the first embodiment, the total reflection mirror 28 and the parallel flat plates 34 and 35 for correcting the aberration of the laser beam
Since the optical pickup 10 is integrated into a unit, the number of components is reduced, the assembly and adjustment of the optical pickup 10 is facilitated, the number of assembly and adjustment steps is reduced, and the cost of members is reduced. Further, since the total reflection mirror 28 and the parallel flat plates 34 and 35 are unitized, the quality of the optical pickup 10 can be stably improved.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup 10 according to a third embodiment of the present invention. The third embodiment is substantially the same as the first embodiment except for the difference between the total reflection mirror and the astigmatism generating means of the first embodiment. Are denoted by the same reference numerals and description thereof is omitted.

Numeral 40 denotes a total reflection mirror, which is a total reflection mirror 28 having a reflection surface inclined at 45 degrees to the beam incident angle direction and a parallel flat plate 41 using a light transmitting member for correcting aberration of the laser beam. 42 are integrally unitized by holders 43 and 44. Recesses into which the total reflection mirror 28 and the parallel flat plates 41 and 42 are inserted are formed in the two components of the holders 43 and 44, respectively, and are held therebetween. The parallel flat plates 41 and 42 of this embodiment are provided at two places between the total reflection mirror 28 and the laser hologram unit 25 and between the total reflection mirror 28 and the objective lens 21.

Next, the operation of the optical system of the optical pickup 10 will be described. A laser beam emitted from the semiconductor laser chip in the laser hologram unit 25 passes through the hologram, the aberration of the laser beam is corrected by the parallel flat plate 41, and the laser beam is reflected by the total reflection mirror in the right angle direction (toward the objective lens 21). The reflected laser beam is corrected for aberration by the parallel flat plate 42, converged by the objective lens 21 into a beam spot having a diameter of about 1 μm, and is focused on a pit row formed on the signal recording surface of the optical disc 12. The focused laser beam is reflected by the pit row, becomes a laser beam having a signal, and returns to the laser hologram unit 25 through the same optical path. Then, the returned laser beam is bent in a predetermined direction by the hologram, reaches the detection photodiode, is converted into an electric signal, and is extracted.

As described above, also in this embodiment,
As in the first embodiment, the holder 4 includes the total reflection mirror 28 and the parallel flat plates 41 and 42 for correcting aberration of the laser beam.
Since the unit is integrally formed by the components 3 and 44, the number of parts is reduced, the assembling and adjustment of the optical pickup 10 is facilitated, the man-hour for assembling and adjusting is reduced, and the member cost is reduced. Further, the total reflection mirror 28 and the parallel flat plates 41, 42
As a unit, the stability of quality can be improved. In addition, the parallel flat plates 41 and 42 are
When the optical pickup 10 is installed at two places between the total reflection mirror 28 and the objective lens 21 and between the total reflection mirror 28 and the objective lens 21, the installation space is dispersed at two places. it can.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup 10 according to a fourth embodiment of the present invention. The fourth embodiment is substantially the same as the first embodiment except for the difference between the total reflection mirror and the astigmatism generating means of the first embodiment. Are denoted by the same reference numerals and description thereof is omitted.

Numeral 45 denotes a total reflection mirror, which is a total reflection mirror 28 having a reflection surface inclined at 45 degrees with respect to the beam incident angle direction, and a parallel flat plate 46 using a light transmitting member for correcting laser beam aberration. 47 are unitized integrally with holders 48 and 49. Recesses into which the total reflection mirror 28 and the parallel flat plates 46 and 47 are inserted are formed in the two parts of the holders 48 and 49, respectively, and they are held therebetween. The parallel flat plates 46 and 47 of this embodiment are substantially the same as the reflection surface of the total reflection mirror 28 in two directions between the total reflection mirror 28 and the laser hologram unit 25 and between the total reflection mirror 28 and the objective lens 21. They are installed in parallel.

Next, the operation of the optical system of the optical pickup 10 will be described. A laser beam emitted from the semiconductor laser chip in the laser hologram unit 25 passes through the hologram, the aberration of the laser beam is corrected by the parallel plate 46, and the laser beam is reflected by the total reflection mirror in the right angle direction (toward the objective lens 21). The reflected laser beam is corrected for aberration by the parallel flat plate 47, is converged by the objective lens 21 into a beam spot having a diameter of about 1 μm, and is converged on a pit row formed on the signal recording surface of the optical disc 12. The focused laser beam is reflected by the pit row, becomes a laser beam having a signal, and returns to the laser hologram unit 25 through the same optical path. Then, the returned laser beam is bent in a predetermined direction by the hologram, reaches the detection photodiode, is converted into an electric signal, and is extracted.

As described above, also in this embodiment,
As in the first embodiment, the total reflection mirror 28 and the parallel flat plates 46 and 47 for correcting the aberration of the laser beam
Since the unit is integrally formed by the components 8 and 48, the number of components is reduced, the assembly and adjustment of the optical pickup 10 are facilitated, and the number of assembly and adjustment steps and the cost of members are reduced. Further, since the total reflection mirror 28 and the parallel flat plates 46 and 47 are unitized, the quality can be improved stably.
In addition, the parallel plates 46 and 47 are connected between the total reflection mirror 28 and the laser hologram unit 25 and the total reflection mirror 2.
Total reflection mirrors 28 at two places between the lens 8 and the objective lens 21
When the optical pickup 10 is installed substantially parallel to the reflecting surface, the installation space can be reduced, so that the optical pickup 10 can be downsized.

Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup 10 according to a fifth embodiment of the present invention. The fifth embodiment is substantially the same as the first embodiment except for the difference between the total reflection mirror and the astigmatism generating means of the first embodiment. Are denoted by the same reference numerals and description thereof is omitted.

Numeral 50 denotes a total reflection mirror section, which includes a total reflection mirror 28 having a reflection surface inclined at 45 degrees to the beam incident angle direction, and a parallel flat plate 51 using a light transmitting member for correcting aberration of the laser beam. Are unitized integrally by holders 52 and 53. Recesses into which the total reflection mirror 28 and the parallel flat plate 51 are inserted are formed in the two parts of the holders 52 and 53, and they are sandwiched and held. still,
In this embodiment, the parallel flat plate 51 is provided on the reflection surface of the total reflection mirror 28 so as to correct the aberrations of the laser beams of both the total reflection mirror 28 and the laser hologram unit 25 and the total reflection mirror 28 and the objective lens 21. It is installed at a predetermined angle to it.

Next, the operation of the optical system of the optical pickup 10 will be described. A laser beam emitted from the semiconductor laser chip in the laser hologram unit 25 passes through the hologram, the aberration of the laser beam is corrected by the parallel flat plate 51, and the laser beam is reflected by the total reflection mirror in the right angle direction (toward the objective lens 21). The reflected laser beam is corrected for aberration by the objective lens 21 side of the same parallel flat plate 51, is converged by the objective lens 21 into a beam spot having a diameter of about 1 μm, and forms a pit row formed on the signal recording surface of the optical disk 12. Collect light. The focused laser beam is reflected by the pit row, becomes a laser beam having a signal, and returns to the laser hologram unit 25 through the same optical path. Then, the returned laser beam is bent in a predetermined direction by the hologram, reaches a detection photodiode, is converted into an electric signal, and is taken out.

As described above, also in this embodiment,
As in the first embodiment, the total reflection mirror 28 and the parallel flat plate 51 for correcting the aberration of the laser beam are provided with holders 52 and 53.
As a result, the number of parts is reduced, the assembly and adjustment of the optical pickup 10 is facilitated, the number of assembly and adjustment steps is reduced, and the cost of members is reduced. Further, since the total reflection mirror 28 and the parallel flat plate 51 are unitized, the quality can be stably improved. In addition, 1
Laser hologram unit 2 using two parallel flat plates 51
It is possible to correct the aberration of the laser beam at two places, that is, on the side of the objective lens 21 and on the side of the objective lens 21, and to reduce the installation space.

Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup 10 according to a sixth embodiment of the present invention. The sixth embodiment is substantially the same as the fifth embodiment except for the difference between the total reflection mirror and the astigmatism generating means of the fifth embodiment. Are denoted by the same reference numerals and description thereof is omitted.

Reference numeral 55 denotes a total reflection mirror section, which includes a total reflection mirror 28 having a reflection surface inclined at 45 degrees with respect to the beam incident angle direction, and a parallel flat plate 56 using a light transmitting member for correcting aberration of the laser beam. Are unitized integrally by holders 57 and 58. Recesses into which the total reflection mirror 28 and the parallel flat plate 56 are inserted are formed in the two parts of the holders 57 and 58, and they are sandwiched and held. still,
In this embodiment, a parallel flat plate 56 is provided on the reflection surface of the total reflection mirror 28 so as to correct the aberration of the laser beams of both the total reflection mirror 28 and the laser hologram unit 25 and the total reflection mirror 28 and the objective lens 21. They are installed in parallel to each other.

As described above, also in this embodiment,
As in the first and fifth embodiments, the total reflection mirror 28 and the parallel flat plate 56 for correcting the aberration of the laser beam are unitized integrally by the holders 57 and 58, so that the number of parts is reduced and the optical pickup 10 Assembling and adjustment are facilitated, so that the number of man-hours for assembling and adjusting can be reduced, and member costs can be reduced. In addition, since the total reflection mirror 28 and the parallel flat plate 56 are unitized, the quality can be improved stably. In addition, it is possible to correct the aberration of the laser beam at two places, that is, the laser hologram unit 25 side and the objective lens 21 side by using one parallel flat plate 56, and it is possible to reduce the installation space. It can respond to miniaturization.

Next, a seventh embodiment of the present invention will be described with reference to FIG. FIG. 7 is a front view (partially sectional) showing a schematic configuration of a main part of an optical pickup 10 according to a seventh embodiment of the present invention. The seventh embodiment is substantially the same as the sixth embodiment except for the difference between the total reflection mirror and the astigmatism generating means of the sixth embodiment. Are denoted by the same reference numerals and description thereof is omitted.

Numeral 60 denotes a total reflection mirror unit which uses a light transmitting member for correcting laser beam aberration on the reflection surface of the total reflection mirror 28 having a reflection surface inclined at 45 degrees to the beam incident angle direction. One parallel flat plate 61 is formed into an integral structure by fixing such as bonding, and is held by holders 62 and 63. The two components of the holders 62 and 63 are formed with concave portions into which the total reflection mirror 28 (including the parallel flat plate 61) is inserted, and are sandwiched and held. Incidentally, the total reflection mirror unit 60 includes the total reflection mirror 28 and the laser hologram unit 2.
The laser beam is installed so as to be able to correct the aberration of the laser beam on both the 5 side and the total reflection mirror 28 and the objective lens 21 side.

As described above, in this embodiment,
Since the total reflection mirror 28 and the parallel plate 61 for correcting the aberration of the laser beam are integrally formed by fixing such as bonding, the holding of the parallel plate 61 becomes unnecessary, and the holders 62 and 63 become unnecessary.
Is more simplified. Therefore, the total reflection mirror unit 6
Since the number of components of the optical pickup 10 is reduced, the assembly and adjustment of the optical pickup 10 is facilitated, so that the number of assembly and adjustment steps and the cost of members can be reduced. The total reflection mirror 28 and the parallel plate 6
1 is integrally formed to improve the quality stability. In addition, it is possible to correct the aberration of the laser beam at two places, that is, the laser hologram unit 25 side and the objective lens 21 side by using one parallel flat plate 61, and it is possible to reduce the installation space. It can respond to miniaturization.

Next, an eighth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup 10 according to an eighth embodiment of the present invention. The eighth embodiment is substantially the same as the seventh embodiment except for the difference between the total reflection mirror and the astigmatism generating means of the seventh embodiment, and therefore has the same configuration as the sixth embodiment. Are denoted by the same reference numerals and description thereof is omitted.

Numeral 65 denotes a total reflection mirror section, in which a transmission layer made of SiO ₂ is formed to a predetermined thickness on the reflection surface of the total reflection mirror 28 having a reflection surface inclined at 45 degrees to the beam incident angle direction. An astigmatism generator 66 for correcting the laser beam aberration is formed integrally with the total reflection mirror 28 and is held by holders 67 and 68. Holders 67, 6
The two parts 8 are formed with concave portions into which the total reflection mirror 28 (including the astigmatism generating section 66) is inserted, and are held between them. The astigmatism generating section 66 of the total reflection mirror section 65 includes the total reflection mirror 28 and the laser hologram unit 2.
The laser beam is set to be able to correct the aberration of the laser beam on both the side 5 and the total reflection mirror 28 and the objective lens 21.

As described above, in this embodiment,
Since the astigmatism generating section 66 for correcting the aberration of the laser beam is formed on the reflection surface of the total reflection mirror 28 and is formed as an integral structure, the holding of the astigmatism generating section 66 becomes unnecessary, and the holders 67 and 68 The shape is more simplified. Therefore,
Since the number of components of the total reflection mirror section 65 is reduced, the assembly and adjustment of the optical pickup 10 becomes easy, so that the number of assembly and adjustment steps and the cost of members can be reduced. In addition, since the total reflection mirror 28 and the astigmatism generation unit 66 are integrally formed, the quality can be stably improved. In addition, laser beam aberration can be corrected at two positions, the laser hologram unit 25 side and the objective lens 21 side, and the installation space can be reduced, so that the optical pickup 10 can be downsized.

Next, a ninth embodiment of the present invention will be described with reference to FIG. FIGS. 9A and 9B are schematic configuration diagrams showing a main part of an optical pickup 10 according to a ninth embodiment of the present invention. FIG. 9A is a front view (only the holder is cross-sectional in the vertical direction), and FIG. Only cross section). The ninth embodiment is the same as the first embodiment.
The other parts are substantially the same as those of the first embodiment, and the same components as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

Reference numeral 70 denotes a total reflection mirror (1), which is a total reflection mirror 28 having a reflection surface inclined at 45 degrees with respect to the beam incident angle direction and astigmatism generating means for correcting aberration of the laser beam (for example, The cylindrical lens 26) and the holders 73 and 74 are integrally unitized. Recesses into which the total reflection mirror 28 and the cylindrical lens 26 are inserted are formed in the two parts of the holders 73 and 74, and they are sandwiched and held. Note that the cylindrical lens 26 of this embodiment is installed between the total reflection mirror 28 and the laser hologram unit 25.

Reference numeral 75 denotes a total reflection mirror (2), which is a total reflection mirror 28 having a reflection surface inclined at 45 degrees with respect to the beam incident angle direction, and astigmatism generating means for correcting aberration of the laser beam (for example, The cylindrical lens 26 is integrally unitized with holders 73 and 74. Recesses into which the total reflection mirror 28 and the cylindrical lens 26 are inserted are formed in the two parts of the holders 73 and 74, and they are sandwiched and held. Incidentally, the cylindrical lens 26 of this embodiment is provided between the total reflection mirror 28 and the objective lens 21. The total reflection mirror (1) 70 and the total reflection mirror (2) 75 are used to change the optical path of the laser beam by 90 degrees.
The reflection surface of the total reflection mirror (1) unit 70 is provided in a state of being inclined by 45 degrees with respect to the reflection surface of the total reflection mirror (2) unit 75.

Next, the operation of the optical system of the optical pickup 10 will be described. The laser beam emitted from the semiconductor laser chip in the laser hologram unit 25 passes through the hologram, the aberration of the laser beam is corrected by the cylindrical lens 26 of the total reflection mirror (1) unit 70, and the laser beam is corrected by the total reflection mirror 28 in the right angle direction ( Total reflection mirror (2) section 75
Direction). Then, the reflected laser beam is reflected by the total reflection mirror 28 of the total reflection mirror (2) unit 75 in a right angle direction (the direction of the objective lens 21). The reflected laser beam is corrected by a cylindrical lens 26 for aberration of the laser beam, converged by an objective lens 21 to a beam spot having a diameter of about 1 μm, and formed as a pit train as minute irregularities formed on a signal recording surface of the optical disc 12. Focus on
The focused laser beam is reflected by the pit row, becomes a laser beam having a signal, and returns to the laser hologram unit 25 through the same optical path. Then, the returned laser beam is bent in a predetermined direction by the hologram, reaches a detection photodiode, is converted into an electric signal, and is taken out.

As described above, according to the present embodiment, the total reflection mirror 28 and the cylindrical lens 26 for correcting the aberration of the laser beam are unitized integrally by the holders 73 and 74, so that the number of parts is reduced. The assembly and adjustment of the optical pickup 10 is facilitated, and the man-hour for assembly and adjustment is reduced. Further, since the total reflection mirror 28 and the cylindrical lens 26 are unitized, the quality of the optical pickup 10 can be stably improved. The total reflection mirror (1) 70 can correct laser beam aberration in a plurality of tangential directions, and the total reflection mirror (2) 75 can correct laser beam aberration in a plurality of radial directions. still,
Although the cylindrical lens 26 is used for the astigmatism generation section, a parallel flat plate or the like using a light transmitting member may be used, and the optical pickup 10 according to the first to eighth embodiments may also be used. A plurality of total reflection mirror units can be used according to the beam path.

[0046]

As described above, according to the present invention, the function of correcting the aberration of the laser beam in the optical pickup can be easily manufactured with a simple structure.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic configuration diagrams showing a main part of an optical pickup according to a first embodiment of the present invention, wherein FIG. 1A is a front view (only the holder is cross-sectional in the vertical direction), and FIG. Only cross section)
It is.

FIG. 2 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup according to a second embodiment of the present invention.

FIG. 3 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup according to a third embodiment of the present invention.

FIG. 4 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup according to a fourth embodiment of the present invention.

FIG. 5 is a front view (partially sectional) showing a schematic configuration of a main part of an optical pickup according to a fifth embodiment of the present invention.

FIG. 6 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup according to a sixth embodiment of the present invention.

FIG. 7 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup according to a seventh embodiment of the present invention.

FIG. 8 is a front view (a partial cross section) showing a schematic configuration of a main part of an optical pickup according to an eighth embodiment of the present invention.

FIGS. 9A and 9B are schematic configuration diagrams showing a main part of an optical pickup according to a ninth embodiment of the present invention, wherein FIG. 9A is a front view (only the holder is cross-sectional in the vertical direction), and FIG. Only cross section)
It is.

[Explanation of symbols]

10 Optical pickup 12 Optical disk 20 Movable part 21 Objective lens 22 Suspension wire 23 Damper yoke 25 ····· Laser hologram unit 26 ··· Cylindrical lens 27, 33, 40, 45, 50, 55, 60, 65 ···
Total reflection mirror part 28 ... Total reflection mirror 29, 30, 36, 37, 43, 44, 48, 49 ...
Holders 52, 53, 57, 58, 62, 63, 67, 68, 7
3, 74 .. Holders 34, 35, 41, 42, 46, 47, 51, 56, 6
1 Parallel plate 66 Astigmatism generating part 70 Total reflection mirror (1) part 75 Total reflection mirror (2) part

Claims (7)

[Claims] 1. A light emitting / receiving unit comprising: a light emitting unit for laser light; and a light receiving unit for receiving reflected laser light having recording information converged on an information recording surface of an optical disk; and a light emitting unit emitted from the light emitting / receiving unit. A total reflection mirror that reflects laser light and laser light reflected from the optical disk, an objective lens that causes the laser light reflected by the total reflection mirror to converge on an information recording surface of the optical disk, the light emitting / receiving unit and the objective An optical pickup comprising: astigmatism generating means for correcting astigmatism due to a lens; and wherein the total reflection mirror and the astigmatism generating means are integrally formed as a unit. 2. The optical pickup according to claim 1, wherein the astigmatism generating means is provided between the light emitting and receiving unit and the total reflection mirror. 3. The optical pickup according to claim 1, wherein said astigmatism generating means is provided between said objective lens and said total reflection mirror. 4. The astigmatism generating means is provided both between the light emitting and receiving unit and the total reflection mirror and between the total reflection mirror and the objective lens. 1. The optical pickup according to 1. 5. The optical pickup according to claim 4, wherein said astigmatism generating means is constituted by a single parallel flat plate. 6. The astigmatism generating means is integrated with the reflection surface of the total reflection mirror so as to be in close contact with the reflection surface of the total reflection mirror, and the total reflection mirror has an astigmatism correction function.
Optical pickup as described. 7. A light-emitting and light-receiving unit comprising: a light-emitting portion for laser light; and a light-receiving portion for receiving reflected laser light converged on an information recording surface of an optical disk and having recorded information; A total reflection mirror (1) for reflecting the laser light and the laser light reflected from the optical disc; and a total reflection mirror (2) for reflecting the light reflected from the total reflection mirror (1) and the laser light reflected from the optical disc. ), An objective lens for converging the laser beam reflected by the total reflection mirror (2) on the information recording surface of the optical disk, and a light emitting and receiving unit side of the total reflection mirror (1) and the total reflection mirror (2). A) astigmatism generating means using a light transmitting member for correcting astigmatism of convergent or divergent light on the objective lens side, wherein the total reflection mirror (1) and the Reflection mirror (2)
And an astigmatism generating means integrally formed as a unit.