JP3510171B2 - Optical head and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head used in a disc recording / reproducing apparatus for projecting a light spot on a disc-shaped information recording medium to optically record / reproduce information, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, disc recording / reproducing apparatuses have been used in DV
Its applications such as D, MD, CD, and CD-ROM are diversifying year by year, and the density, size, performance, quality, and added value are increasing. In particular, in a disk recording / reproducing apparatus using a recordable magneto-optical medium, demands for data and music recording are on the increase, and further miniaturization, thinning, high performance, and high recording density are required. It has been demanded.

Conventionally, many reports have been made on the technology relating to the optical head for the magneto-optical disk.

An optical head for a magneto-optical disk will be described below as an example of a conventional disk recording / reproducing apparatus with reference to the drawings.

FIG. 23 is an exploded perspective view showing a schematic structure of a conventional optical head, FIG. 24 is an enlarged sectional view showing a method of fixing a reflection mirror in the optical head of FIG. 23, and FIG.
23A is an optical path diagram showing the optical path of the optical head of FIG. 23, FIG. 25B is a plan view showing the light receiving region and the light spot of the light receiving surface of the multi-segment photodetector, and FIG. It is a signal circuit diagram showing a processing method of a signal obtained by a multi-division photodetector of an optical head.

23 to 26, 101 is a semiconductor laser, 102 is a collimating lens, 103 is a diffraction grating, 104 is a compound element composed of a beam splitter 104a, a polarization separation element 104b and a folding mirror 104c, and 105 is an objective lens. , 106 is an information recording medium (magneto-optical disk) having a magneto-optical effect, 107 is a monitor light receiving element, 108 is a convex lens, 109 is a concave cylindrical lens, 110 is a holding member, 111 is a multi-segment photodetector, and 112 and 113. Is the focus of the light spot, 114 is the main beam (P
Polarized light), 115 is a main beam (S-polarized light) formed on the multi-segment photo detector 111, and 116 is the multi-segment photo detector 11
Main beam (P + S polarization) 117 formed on 1
Is the light spot of the preceding beam of the sub-beams, 11
Reference numeral 8 denotes a light spot of the trailing beam of the sub beams. Reference numeral 119 is a four-division light receiving area, 120 is a leading beam light receiving area, 121 is a trailing beam light receiving area, and 122a and 122a.
Reference numeral b is an information signal light receiving area, 123 is a subtractor, and 124 is an adder. Further, 125 is an optical stand, 126 is a reflection mirror, 127 is an adhesion reference surface of the optical stand 125, 128 is an adhesion reference surface of the reflection mirror 126, 129 is a positioning wall of the reflection mirror 126 formed on the optical stand 125, and 130 is An adhesion reservoir, 131 is a UV adhesive, and 132 is an objective lens driving device.

The conventional optical head having the above structure will be described below.

The reflection mirror 126 is fixed to the optical table 125 as follows. As shown in FIGS. 23 and 24, a positioning wall 129 for positioning the reflection mirror 126 is formed on the optical bench 125. The reflection mirror 126 is installed along the positioning wall 129. After that, as shown in FIG. 24, a preload 151 in a direction parallel to the reflection surface of the mirror 126 and a preload 152 in a direction perpendicular to the reflection surface of the mirror 126 are applied to one side surface (lower end surface) of the reflection mirror 126. And a positioning wall 129 of the optical stand 125, an adhesion reference surface (surface opposite to the reflection surface) 128 of the reflection mirror 126, and an adhesion reference surface 127 of the optical stand 125.
The reflection mirror 126 is positioned with high accuracy by bringing them into contact with each other. In this state, the UV adhesive 131 is applied to the adhesion reservoir 130, and ultraviolet rays are irradiated to fix the reflection mirror 126 to the optical base 125 with the UV adhesive 131 with high precision.

Next, the operation of the optical head in which various parts are incorporated will be described in a completed state.

The light emitted from the semiconductor laser 101 is
The collimator lens 102 converts the light into parallel light, and the diffraction grating 103 separates the light into different parallel light beams.
The plurality of different parallel light beams pass through the beam splitter 104a of the composite element 104, and the objective lens 105 incorporated in the objective lens driving device 132 allows the information recording medium 10 to be recorded.
A light spot of a main beam having a diameter of about 1 micron and light spots of a preceding beam and a trailing beam as sub-beams of a so-called three-beam method are formed on the surface 6. The light spots of the leading beam and the trailing beam are formed on the same track as the light spot of the main beam and at regular intervals before and after the light spot of the main beam. The parallel luminous flux reflected by the beam splitter 104a of the composite element 104 enters the monitor light receiving element 107 and controls the drive current of the semiconductor laser 101.

The reflected light from the information recording medium 106 follows the opposite path, and the beam splitter 10 of the composite element 104.
It is reflected and separated by 4a and enters the polarization separation element 104b. The semiconductor laser 101 is installed such that the polarization direction of light emitted from the semiconductor laser 101 is parallel to the paper surface of FIG. The incident light on the polarization separation element 104b is separated by the polarization separation element 104b into three light fluxes, that is, two light fluxes whose polarization components are orthogonal to each other and two light fluxes having two polarization components orthogonal to each other.
The two light beams are reflected by the reflection mirror 104c.

The reflected light transmitted through the composite element 104 enters a substantially cylindrical convex lens 108 and becomes convergent light, and enters a substantially cylindrical concave cylindrical lens 109. Here, the concave cylindrical lens 109 is, in this example,
It is provided so as to have a lens effect at an angle of approximately 45 degrees with respect to the image of the recording track of the information recording medium 106 existing in the direction of W1.

The light transmitted through the concave cylindrical lens 109 produces astigmatism which is a focus error signal detecting means. In the surface having no lens effect of the concave cylindrical lens 109, the optical path becomes a solid line and converges at the focal point 112, and in the surface having the lens effect, the optical path shown by a broken line converges at the focal point 113.

The concave cylindrical lens 109 has a direction W2 which has the lens effect of the concave cylindrical lens 109.
(Not shown) is rotationally adjusted so as to be approximately 45 degrees with respect to the holding member 110, and the convex lens 108 and the concave cylindrical lens 109 are fixed by the holding member 110 at a predetermined distance in the optical axis direction.

The multi-segment photodetector 111 has a light-receiving surface with a focal point 11.
It is installed so as to be located approximately in the middle of the focal point 113 and the focal point 2. By taking the sum of the diagonals of the electrical signals generated in the central four-division light receiving region 119 and subtracting them,
The focus error signal is detected by the so-called astigmatism method. By obtaining the difference between the light spot 117 of the preceding beam and the light spot 118 of the following beam, a tracking error detection signal by the so-called three-beam method is detected. An information signal of the information recording medium can be detected by the differential detection method by calculating the difference between the P-polarized main beam 114 and the S-polarized main beam 115.
Furthermore, the pre-pit signal can be detected by taking the sum of them.

[0016]

However, in the above-mentioned conventional configuration, the positioning wall 129 is provided in order to bond and fix the reflection mirror 126 to the optical base 125 with high positional accuracy. As a result, the overall height of the optical bench 125 becomes high. As a result, the total height of the optical head becomes high.

Further, the optical table 125 has a solid difference, and there is an angular variation of the adhesion reference surface 127 with respect to the reference surface of the optical table 125. Therefore, the objective lens 105
The optical axis incident on the optical axis changes significantly, resulting in unstable performance of the optical head.

On the other hand, in order to reduce the angle variation of the optical axis of the optical head, it is necessary to accurately process or mold the adhesive reference surface 127 with respect to the reference surface of the optical table 125. Will be expensive.

Further, the UV adhesive 131 may expand or contract due to changes in the temperature environment. In the conventional configuration, the UV adhesive 131 is filled in the adhesive pool 130,
Since this adheres to a part of the back surface of the reflection mirror 126, the reflection mirror is expanded and contracted by the UV adhesive 131.
The mounting angle of 126 changes slightly. As a result,
There is also a problem that the optical axis of the optical head changes and the performance of the optical head deteriorates.

Further, since the process of adhering and fixing the reflection mirror 126 to the optical table 125 with the UV adhesive 131 requires high working accuracy, there is a problem in that it takes too much time and cost and mass productivity deteriorates. .

In view of the above-mentioned conventional problems, the present invention eliminates the positioning wall 129 of the optical base 125 and the bonding reference surface 127 for positioning the reflection mirror 126, and is thin,
It is an object of the present invention to provide an optical head with high accuracy, low price, high reliability and high productivity.

[0022]

The present invention has the following constitution in order to achieve the above object.

A method of manufacturing an optical head according to a first aspect of the present invention includes a light source, an objective lens, a reflection mirror which reflects a light beam from the light source and makes it enter the objective lens.
A method of manufacturing an optical head having an optical base for holding the light source and the reflection mirror, wherein the reflection mirror and the optical base are installed in an external jig having a mirror holding portion for holding the reflection mirror. In this state, the reflection mirror and the optical bench are bonded and fixed.

According to the first manufacturing method described above, since the reflection mirror is held by the mirror holding portion of the external jig and fixed to the predetermined position of the optical stand, the positioning that the conventional optical stand has. Eliminates the need for walls and reference planes. This allows
The optical head can be made smaller and thinner. Furthermore, if the mirror holding part of the external jig that is repeatedly used is processed with high accuracy, it is not necessary to have a high degree of molding accuracy or processing accuracy for the reflection mirror mounting part of the optical stand, so the dimensional accuracy of the optical stand is greatly increased. It is possible to reduce the cost, and the cost of the optical head can be reduced. In addition, the problem of destabilizing the quality of the optical head due to variations in the processing accuracy of the mirror mounting portion of the optical table is solved.

In the first manufacturing method described above, it is preferable that the reflection mirror is installed in the mirror holding portion at a predetermined angle. According to such a preferable configuration, the mounting angle of the reflection mirror to the optical bench is stabilized, and the change of the optical axis can be suppressed.

In the above preferred manufacturing method,
It is preferable that the mirror is installed such that the reflection surface of the reflection mirror comes into contact with the angle reference surface of the mirror holding portion. Since the reflecting surface of the reflecting mirror is brought into contact with the angle reference surface, the reflecting mirror can be attached with a highly accurate attaching angle by a simple method, and desired reflection characteristics can be obtained accurately and stably.

In the first manufacturing method, it is preferable that the reflection mirror is brought into contact with the mirror holding portion to define the position in the direction parallel to the reflection surface of the reflection mirror. According to this preferable configuration, the mounting position of the mirror can be maintained with high accuracy by a simple method. Further, since it is not necessary to provide a mechanism for aligning the direction on the optical table side, the processing accuracy of the mirror mounting portion of the optical table is relaxed, and the cost of the optical head is reduced.

In the first manufacturing method, it is preferable that the reflection mirror is not in direct contact with the optical bench. According to this structure, the reflection mirror is held on the optical table via the adhesive, so that the processing accuracy of the mirror mounting portion of the optical table can be relaxed.

Further, in the above-mentioned first manufacturing method, it is preferable to bond and fix the two side surfaces facing each other, which are substantially orthogonal to the reflecting surface of the reflecting mirror, in the vicinity of the center thereof. According to such a preferable configuration, the angle change and the position change of the reflection mirror due to the expansion and contraction of the adhesive when left in the environment are reduced, the change in the optical axis is reduced, and a highly reliable optical head having excellent environmental characteristics is provided. Can be realized.

Further, in the above-mentioned first manufacturing method, it is preferable that the reflection mirror has a flat plate shape.

In the above first manufacturing method, U
It is preferable to bond and fix using a V adhesive. This is because the workability of adhesion and fixing is improved.

The optical head according to the first aspect of the present invention includes a light source, an objective lens, a reflection mirror that reflects the light flux from the light source and makes the light incident on the objective lens, the light source and the reflection mirror. And an optical head for holding the reflection mirror, wherein the reflection mirror is adhesively fixed to the optical base, and the reflection mirror mounting portion of the optical base is brought into contact with the reflection mirror by It is characterized in that a reference surface that defines the mounting angle is not formed.

According to the first optical head described above, since the optical stand does not have the reference surface for mounting the reflection mirror, the optical head can be made smaller and thinner. Further, since a high degree of molding accuracy or processing accuracy is not required for the reflection mirror mounting portion of the optical table, the dimensional accuracy of the optical table can be greatly relaxed, and the cost of the optical head can be reduced. In addition, the problem of destabilizing the quality of the optical head due to variations in the processing accuracy of the mirror mounting portion of the optical table is solved.

In the above first optical head, it is preferable that the reflection mirror is not in direct contact with the optical bench. According to this structure, the reflection mirror is held on the optical table via the adhesive, so that the processing accuracy of the mirror mounting portion of the optical table can be relaxed.

In the above first optical head,
It is preferable that the reflection mirror is bonded and fixed near the center of two opposite side surfaces that are substantially orthogonal to the reflection surface. According to such a preferable configuration, the angle change and the position change of the reflection mirror due to the expansion and contraction of the adhesive when left in the environment are reduced, the change in the optical axis is reduced, and a highly reliable optical head having excellent environmental characteristics is provided. Can be realized.

In the above first optical head,
It is preferable that the reflection mirror has a flat plate shape.

In the above first optical head,
It is preferable that the reflection mirror is adhesively fixed using a UV adhesive. This is because the workability of adhesion and fixing is improved.

The optical head according to the second aspect of the present invention is located between the light source, the objective lens that forms a light spot on the information recording medium, and the objective lens and the light source. Is an optical head including a light flux reflecting means for reflecting the light flux of the light to enter the objective lens, and a resin optical stand for holding the light source, wherein the light flux reflecting means is a resin or glass base substrate. It is a reflection mirror in which a reflection film is formed on a material, and the light flux reflecting means and the resin optical base are integrally molded.

According to the second optical head described above, the optical stand is made by resin molding, and the resin or glass reflecting mirror is installed on the molding die. At this time, after strictly controlling the position and angle of the reflection mirror to be installed with respect to the mold, resin molding is performed to integrally form the optical stand and the reflection mirror. As a result, the adhesion reference plane and the positioning wall of the reflection mirror, which the conventional optical stand has, can be eliminated, so that the optical head can be made smaller and thinner. Further, it is not necessary to manage the molding accuracy or processing accuracy of the bonding reference surface of the reflection mirror and the positioning wall, which is included in the conventional optical table, so that the dimensional accuracy of the optical table can be significantly relaxed. At the same time, an optical head with high precision and stable quality can be obtained. Further, since the work of adhering and fixing the reflection mirror is unnecessary, the mass productivity of the optical head is improved and the cost can be reduced.

Further, the reflection mirror is not fixed to the optical table with an adhesive, but the reflection mirror is integrally molded. Therefore, the influence of expansion and contraction of the adhesive due to a change in temperature environment is eliminated. As a result, it is possible to significantly reduce the angle change and the position change of the reflection mirror, the change of the optical axis of the optical head becomes small, and it is possible to realize a highly reliable optical head having excellent environmental characteristics. .

The optical head according to the third aspect of the present invention is located between the light source, the objective lens that forms a light spot on the information recording medium, and the objective lens and the light source. A light flux reflecting means for reflecting the light flux of to enter the objective lens, and an optical head made of resin for holding the light source, wherein the light flux reflecting means is provided on the surface of the resin made optical stand. It is characterized in that a reflection film is formed.

According to the third optical head described above, the optical base is made by resin molding, and the base portion of the light flux reflecting means is also molded at the time of resin molding. After forming, a reflection film is formed by metal vapor deposition or the like to complete the light flux reflecting means.
That is, since the reflection mirror is not used, the reflection mirror is broken,
There is no chipping, and there is no need to consider the dimensional margin due to the positioning error of the reflection mirror. Further, since the bonding reference surface and the positioning wall of the reflection mirror which the conventional optical stand has can be eliminated, the optical head can be made smaller and thinner. Further, since the positioning work and the adhesive fixing work of the reflection mirror are unnecessary, the mass productivity of the optical head is improved and the cost can be reduced.

Further, since the base portion of the light flux reflecting means and the optical base are simultaneously molded by resin as an integrated component, the influence of expansion and contraction of the adhesive due to changes in temperature environment is eliminated.
As a result, it is possible to significantly reduce the angle change and position change of the light flux reflecting means, reduce the optical axis change of the optical head, and realize a highly reliable optical head with excellent environmental characteristics. Become.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic view showing a method of attaching a reflection mirror to an optical base according to Embodiment 1, FIG. 1 (A) is a plan view and FIG. 1 (B). ) Is Figure 1
FIG. 1 is a cross-sectional view taken along the line I-I of FIG.
FIG. 1C is a sectional view taken along the line II-II in FIG. 2 is a partially enlarged view showing details of the mounting portion of the reflection mirror of FIG. 1, FIG. 2 (A) is a view seen from a direction perpendicular to the reflection surface of the reflection mirror, and FIG. 2 (B) is a view. Two
FIG. 3 is a sectional view taken along line III-III of FIG. FIG. 3 is a partially enlarged view showing details of the mounting portion of the reflection mirror of FIG. 1, FIG. 3 (A) is a view seen from the objective lens side, and FIG. 3 (B) is IV of FIG. 3 (A). FIG. 4 is a cross-sectional view as seen from the direction of the arrow along line IV. FIG. 4 is an exploded perspective view showing a schematic configuration of the optical head according to the first embodiment. FIG. 5 is an optical path diagram showing an optical path of the optical head according to the first embodiment, FIG. 5 (A) is a front view, and FIG. 5 (B) is a side view. FIG. 6 is a signal circuit diagram showing a method of processing a signal obtained by the multi-division photodetector of the optical head according to the first embodiment. FIG. 7 is an exploded perspective view showing a method of adjusting the objective lens driving device and the optical base in the optical head of the first embodiment. FIG. 8 is an overall perspective view of the optical head according to the first embodiment.

1 to 8, reference numeral 1 denotes a semiconductor laser 1.
a, a multi-segment photodetector 1b, a light emitting / receiving element including a hologram element, 2 is a composite element including a beam splitter 2a, a folding mirror 2b, and a polarization splitting element 2c, 3 is a reflection mirror, and 4 is a reflection mirror-3. Reflective surface (reference surface) of 5
Is an objective lens, 6 is an objective lens holder for fixing and holding the objective lens 5, 7 is an information recording medium (magneto-optical disk) having a magneto-optical effect, and 8 is the objective lens 5 in the focus direction (normal direction) of the information recording medium 7. ) And an objective lens driving device for driving in the radial direction, 9 is a base for holding the objective lens driving device 8, 9a is a positioning hole provided in the base 9, 10 is an optical base, 11 is a reference surface of the optical base 10, 1
Reference numeral 2 denotes a focus error signal detecting light spot formed on the light receiving and emitting element 1, 13 denotes a tracking error signal detecting light spot formed on the light receiving and emitting element 1, and 14 denotes a light receiving and emitting element 1 formed on the light receiving and emitting element 1. Main beam (P polarized), 15
Is a main beam (S-polarized light) formed on the light emitting / receiving element 1, 16 is a focus error signal light receiving region, 17 is a tracking error signal light receiving region, 18 is an information signal light receiving region,
Reference numeral 19 is a subtractor, 20 is an adder, and 21 and 22 are the focal points of a light spot for detecting a focus error signal. Further, 23 is a positioning hole formed in the optical table 10, 24 is an external jig, 25 is a reference surface for adhesion of the reflection mirror 3 formed in the external jig 24, 26 is an adhesion reservoir of the optical table 10, 27
Is a positioning pin formed on the external jig 24, 28 is a positioning wall formed on the external jig 24, 29 is a UV adhesive,
Reference numeral 30 is an optical axis, 31 is an adhesive for fixing the base 9 to the optical table 10, 32 is a guide axis for moving the optical table 10, and 37 is a light spot condensed on the information recording medium 7. .

The first embodiment of the present invention configured as described above will be described below.

For convenience of explanation below, FIG.
As shown in (A), the X-axis (radial direction of the magneto-optical disk 7) and the Y-axis (magneto-optical disk 7) are used as orthogonal coordinate axes.
Tangential direction) and the Z axis (normal direction of the magneto-optical disk 7). Further, as shown in FIG. 1C, the direction parallel to the reflecting surface of the reflecting mirror 3 and orthogonal to the X axis is Z ′.
The axis.

The reflection mirror 3 is fixed to the optical table 10 as follows.

In this embodiment, an external jig 24 for fixing the reflection mirror 3 is used. The external jig 24 is
A mirror holding unit having a positioning pin 27 for positioning the optical table 10 by fitting it into the positioning hole 23 of the optical table 10, an adhesive reference surface 25 for holding the reflection mirror 3 at a predetermined position and a predetermined angle, and a positioning wall 28. Have and. The adhesion reference surface 25 defines the mounting angle of the reflection mirror 3, and the positioning wall 28 positions the reflection mirror 3 in the Z′-axis direction (that is, Z).
Axial position). The upper surface of the external jig 24 is processed with high precision, and the angle error between the upper surface and the bonding reference surface 25 and the Z of the intersection of the bonding reference surface 25 and the positioning wall 28.
The axial position is controlled with high accuracy.

As shown in FIG. 1, the reflection mirror 3 is placed on the adhesion reference surface 25 of the external jig 24 so that the reflection surface 4 is on the adhesion reference surface 25 side, and the preload 51 in the Z′-axis direction is provided.
To push the reflection mirror 3 against the positioning wall 28,
Position in the Z'axis direction. In this state, the optical stand 10
Is installed on the external jig 24 so that the reference surface 11 is on the external jig 24 side. At this time, the positioning pin 27 of the external jig 24 is fitted into the positioning hole 23 of the optical stand 10 to perform positioning in the XY plane. Then, the reference surface 11 serving as the angle reference of the optical table 10 and the upper surface of the external jig 24 are preloaded 52 in a direction perpendicular to the upper surface of the external jig 24.
To give close contact. The position of the reflection mirror 3 in the X-axis direction does not need to be accurately positioned, but in the case of positioning, for example, one of the ends of the reflection mirror 3 in the X-axis direction is brought into contact with the reflection mirror mounting portion of the optical table 10. It can be positioned by making contact. Alternatively, the distance between the two wall surfaces of the mirror mounting portion of the optical table 10 facing each other in the X-axis direction is set to be larger than the length of the reflection mirror 3 in the X-axis direction, and the reflection mirror 3 and the optical table 10 directly contact in the X-axis direction. You may not.

Further, a preload 53 in a direction perpendicular to the reflection surface of the reflection mirror 3 is applied to the reflection mirror 3 to bring the reference surface 4 of the reflection mirror 3 into close contact with the adhesion reference surface 25 of the external jig 24. In this state, the adhesive reservoir 26 is filled with the UV adhesive 29, and the reflection mirror 3 and the optical base 10 are bonded and fixed with high accuracy by irradiating with ultraviolet rays. At this time, the bonding positions are two positions, which are substantially perpendicular to the X-axis direction, near the center of a pair of side surfaces of the reflecting mirror 3 which face each other. The adhesion reservoir 26 is formed in a concave shape on two opposing surfaces that are substantially perpendicular to the X-axis direction of the reflection mirror attachment portion of the optical table 10 so that the reflection mirror 3 can be fixed by adhesion at such a position.

FIGS. 2 and 3 are partially enlarged views showing a state in which the reflection mirror 3 is adhesively fixed to the optical table 10 in the vicinity of the center of a pair of opposed side surfaces that are substantially orthogonal to the reflection surface. In the present embodiment, the UV adhesive 29 is located substantially at the center of each side surface (more preferably, the position where the UV adhesive 29 in the Z′-axis direction substantially coincides with the Z′-axis incident position of the optical axis 30). 2), and is provided at a position substantially symmetrical with respect to the plane including the incident optical axis and the reflected optical axis. Therefore, even if the UV adhesive 29 expands or contracts due to the change in the environmental temperature, it is unlikely to be affected. That is, the displacement of the reflection mirror 3 in the horizontal direction (in-plane direction including the X axis and the Y axis), the vertical direction (Z axis direction), and the rising direction (the direction perpendicular to the reflection surface 4 of the reflection mirror 3) with respect to the optical table 10. The amount can be significantly reduced. As a result, the change in the optical axis can be reduced and the quality of the optical head can be significantly improved.

The light emitting / receiving element 1 and the objective lens driving device 8 are mounted on the optical stand 10 to which the reflection mirror 3 is adhered and fixed by the above-described method to form an optical head.

The light emitting / receiving element 1 is fitted to the optical table 10 and fixed with an adhesive. The mounting positions of the light emitting / receiving element 1 in the X-axis, Y-axis, and Z-axis directions are defined by fitting with the optical base 10, and the light-receiving surface is installed so as to be located approximately in the middle of the focal points 21 and 22 of the light spot. To be done.

The objective lens driving device 8 holds the positioning hole 9a of the base 9 with an external chucking pin (not shown) and adjusts the position and angle described later, and then, an adhesive (for example, UV adhesive). It is fixed to the optical table 10 at 31.

The light emitted from the semiconductor laser 1a of the light emitting / receiving element 1 is separated into a plurality of different light fluxes by the hologram element. A plurality of different light fluxes pass through the beam splitter 2a of the composite element 2, are reflected by the reflection mirror 3, and are fixed as the objective lens holder 6 by the objective lens 5 to form a light spot 37 having a diameter of about 1 micron on the information recording medium 7. Collected. Also, the beam splitter 2 of the composite element 2
The light flux reflected by a is incident on a laser monitor light receiving element (not shown) to control the drive current of the semiconductor laser 1a.

The reflected light from the information recording medium 7 follows the reverse path, is reflected and separated by the beam splitter 2a of the composite element 2, and is turned over by the folding mirror 2b and the polarization separation element 2c.
Incident on.

The polarization direction of the light emitted from the semiconductor laser 1a is set so as to be parallel to the paper surface in FIG. 5A, and the incident light incident on the polarization separation element 2c is polarized by the polarization separation element 2c. The components are separated into two light fluxes orthogonal to each other and enter the information signal light receiving area 18.

Of the reflected light from the information recording medium 7, the light beam that has passed through the beam splitter 2a is separated into a plurality of light beams by the hologram element, and is focused on the focus error signal light receiving area 16 and the tracking error signal light receiving area 17. .

The focus servo is a so-called SSD (spot
The size detection method is used, and the tracking servo is performed by the so-called push-pull method.

Further, the main beam 14 composed of P-polarized light
By calculating the difference between the main beam 15 composed of S-polarized light and S-polarized light, it is possible to detect the information signal of the information recording medium by the differential detection method. Furthermore, the pre-pit signal can be detected by taking the sum of them.

To adjust the focus error signal and the tracking error signal, the positioning hole 9a of the base 9 is held by an external chucking pin (not shown) to define the position in the Z-axis direction, and then the objective lens driving device 8 is moved to the X position. Axial direction (radial direction) and Y-axis direction (tangential direction)
(See FIG. 7), and the output of the tracking error signal light receiving area 17 is adjusted to be substantially uniform. Further, in the adjustment of the relative inclination between the information recording medium 7 and the objective lens 5, similarly to the above, the base 9 is gripped by the external chucking pin (not shown), and the objective lens driving device 8 is moved in the radial direction (around the Y axis). ) Rotating in θR and tangential direction (around the X axis) θT (see FIG. 7). After the above adjustment, the objective lens driving device 8 and the optical base 10 are bonded and fixed with the adhesive 31 (see FIG. 8).

As described above, according to the first embodiment, the setting of the mounting position and the mounting angle of the reflection mirror-3 on the optical base 10 is performed by using the bonding reference surface 25 and the positioning wall 28 of the external jig 24. By doing so, it is possible to eliminate the positioning wall of the reflection mirror and the bonding reference surface, which are included in the conventional optical bench. As a result, the optical head can be made smaller and thinner. Further, since the mounting portion of the reflection mirror 3 of the optical table 10 is not required to have a high degree of molding accuracy or processing accuracy, the dimensional accuracy of the optical table 10 can be greatly relaxed, and the cost of the optical head can be reduced. Become.

Further, since the optical mirror 10 is fixedly bonded to the optical table 10 at two locations near the center of a pair of side surfaces facing each other of the reflecting mirror 3, the angle change and the position of the reflecting mirror 3 due to the expansion or contraction of the adhesive when left in the environment. Less variability. Therefore, the change in the optical axis becomes small, and it is possible to realize a highly reliable optical head having excellent environmental change characteristics.

In the first embodiment, the bonding reference surface 25 is based on the upper surface of the external jig 24, and the optical table 10 is used.
Although the angle reference of 1 is used as the reference surface 11 and the reflection mirror 3 is adhered and fixed to the reference surface 11 with high angle accuracy, the other reference surface of the optical base 10 or the two guide shafts 32 are used as a reference for external reference. It goes without saying that the same effect can be obtained even if the adhesion reference surface 25 of the jig 24 is formed and the reflection mirror 3 is adhesively fixed.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG.

9A and 9B are schematic views showing a method of attaching the reflection mirror to the optical bench according to the second embodiment. FIG. 9A is a plan view and FIG. 9B is FIG. 9A. 9A is a cross-sectional view taken along the line V-V in FIG. 9A, and FIG. 9C is FIG. 9A.
FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 9, members having the same functions as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

The present embodiment differs from the first embodiment in that the reflection mirror 3 is positioned in the X-axis direction.
A pair of positioning walls 3 facing the external jig 24 in the X-axis direction
5 is formed, and the reflection mirror 3 is brought into contact with the positioning wall 35, so that the reflection jig 3 is also positioned in the X-axis direction by the external jig 24. Therefore, the reflection mirror 3 and the optical stand 10 are not in contact with each other.

According to the present embodiment, the dimensional accuracy of the mirror mounting portion of the optical table 10 (particularly in the first embodiment, the reflection mirror 3 is brought into contact with the reflection mirror 3 by being brought into contact therewith).
It is possible to further relax the processing accuracy of the mirror mounting portion that regulates the position in the X-axis direction, and it is possible to realize an optical stand at a lower cost. Furthermore, the optical table 10
Since the reflection mirror 3 and the reflection mirror 3 are not in contact with each other at all, it is possible to realize an optical head with higher reliability against changes in the temperature environment.

(Third Embodiment) FIG. 10 is an exploded perspective view showing a schematic structure of an optical head according to a third embodiment. Figure 1
FIG. 1A is a cross-sectional view of the state immediately after integrally molding the optical bench and the reflection mirror, taken along a plane including the optical axis.
FIG. 3B is an exploded perspective view showing a state in which the reflection mirror is separated to show the structure of the optical bench after integrally molded. FIG. 12 is an exploded perspective view showing a method of adjusting the objective lens driving device and the optical table in the optical head according to the third embodiment. FIG. 13 is an overall perspective view showing a completed state of the optical head of the third embodiment. 14A and 14B are optical path diagrams showing the optical paths of the optical head according to the third embodiment. FIG. 14A is a front view and FIG. 14B is a side view. FIG. 15 is a signal circuit diagram showing a method of processing a signal obtained by the multi-division photodetector of the optical head according to the third embodiment.

In FIGS. 10 to 15, reference numeral 1 is a semiconductor laser 1a, a multi-division photodetector 1b, a light emitting / receiving element including a hologram element, and 2 is a beam splitter 2a, a folding mirror 2b, and a polarization separation element 2c. Composite element,
Reference numeral 3 is a reflection mirror (light flux reflecting means), 4 is a reflection surface of the reflection mirror 3, 5 is an objective lens fixed to an objective objective lens holder 6, 7 is an information recording medium (magneto-optical disk) having a magneto-optical effect, 8 Is an objective lens driving device for driving the objective lens 5 in the plane wobbling direction (normal direction) and radial direction of the information recording medium 7, 9 is a base which is a component of the objective lens driving device 8, and 10 is a resin material. An optical stand, 12 is a light spot for detecting a focus error signal formed on the light emitting / receiving element 1, 13 is a light spot for detecting a tracking error signal formed on the light emitting / receiving element 1, and 14 is a light receiving / emitting element 1.
A main beam (P-polarized light) formed above, 15 a main beam (S-polarized light) formed on the light emitting / receiving element 1, 16 a focus error signal light receiving area, 17 a tracking error signal light receiving area, and 18 an information signal The light receiving area, 19 is a subtractor, 20 is an adder, and 21 and 22 are the focal points of the light spots for focus error signal detection. 30 is an optical axis, 31
Is an adhesive for fixing the base 9 to the optical table 10, 32
Is a guide axis for moving the optical table 10, and 37 is a light spot focused on the information recording medium 7. 40 is a metal mold for resin molding, 41 is a reference plane for the reflection mirror, 42
Is a positioning wall for the reflecting mirror. The reference surface 41 and the positioning wall 42 are formed on the mold 40 and form a reflection mirror fixing portion. Reference numeral 45 is a first holding portion formed on the optical bench 10, and 46 is a second holding portion formed on the optical bench 10.

The third embodiment of the present invention configured as described above will be described below.

For convenience of description below, FIG.
12 to 12, the X-axis (radial direction of the magneto-optical disk 7) and the Y-axis (magneto-optical disk 7) are used as orthogonal coordinate axes.
Tangential direction) and the Z axis (normal direction of the magneto-optical disk 7).

The reflection mirror 3 as the light flux reflecting means comprises a flat base material made of resin or glass and a reflecting surface 4 on one side thereof. The reflective surface 4 is formed of, for example, a reflective film formed by vapor deposition of aluminum. However, the reflecting surface 4 is not limited to this, and may be a vapor-deposited film of chromium or a dielectric material as long as it is a vapor-deposited film having excellent aberration characteristics of the reflected light flux. A well-known AR (anti-reflection) coat is preferably applied to the surface of the reflecting surface 4.

The reflection mirror 3 thus created is
It is installed in a resin molding die 40 having a reflection mirror fixing portion (see FIG. 11A). The reflection mirror fixing portion includes a reference surface 41 that contacts the reflection surface 4 of the reflection mirror 3 and a positioning wall 42 that contacts the lower end surface of the reflection mirror 3. Angle error of the reference plane 41, and the reference plane 41 and the positioning wall 42
The position of the intersection with the Z-axis direction is managed with high accuracy.

The reflecting surface 3 of the reflecting mirror 3 is set on the side of the reference surface 41, and the reflecting mirror 3 is installed in the reflecting mirror fixing portion of the mold 40. Then, the preload 4 in the direction parallel to the reflecting surface 4
3 is applied to the reflection mirror 3, and the lower end surface of the reflection mirror 3 is brought into contact with the positioning wall 42 to perform positioning in the Z-axis direction. In addition, a preload 44 is applied from the rear surface of the reflection mirror 3 to bring the reflection surface 4 into close contact with the reference surface 41 and make the installation angle of the reflection mirror 3 constant. In this state, a mold (not shown) is brought into close contact with the mold 40, and the resin is injected into the cavity formed inside. Figure 1 (A) when the mold is separated
As shown in FIG. 5, a resin optical stand 10 in which the reflection mirror 3 is integrally molded (insert molded) is obtained. As is apparent from the above, the mounting angle of the reflection mirror 3 with respect to the optical table 10 and the position in the Z-axis direction are determined by the reference surface 41 and the positioning wall 42 of the mold 40.

The resin material of the optical table 10 is, for example, PPS.
(Polyphenylene sulfide) can be used, but is not limited thereto, and may be, for example, acrylic, polycarbonate, liquid crystal polymer, polyolefin resin, or other general resin.

The temperature of the resin material during the integral molding is usually about 20.
It is 0 ° C to 400 ° C. On the other hand, when the reflection mirror 3 is made of glass, the softening point of the glass is 500 ° C. or higher. Therefore, the problem of performance deterioration of the reflection mirror 3 does not occur during integral molding, including the aluminum reflection film of the reflection surface 4 and the AR coat provided as necessary.

FIG. 11B is an exploded perspective view showing the state in which the reflection mirror 3 is separated so that the structure of the mounting portion of the reflection mirror 3 in the optical stand 10 thus integrally molded can be seen. . As shown in FIGS. 10 and 11B, the reflection mirror 3 is held on the optical table 10 by the first holding part 45 and the second holding part 46 which are integrally formed on the optical table 10. . The first holding unit 45 holds the reflection mirror 3 at both side surfaces of the reflection mirror 3 in the X-axis direction and both ends of the reflection surface 4 in the X-axis direction. In addition, the second holding portion 46,
The reflection mirror 3 is held by the back surface of the reflection mirror 3. The reflection mirror 3 is accurately and strongly fixed to the optical table 10 by the holding force of the first holding portion 45 and the second holding portion 46, without looseness or looseness. As described above, since the holding portions are not formed on the two upper and lower side surfaces of the reflection mirror 3 in the Z-axis direction, the optical stand 10 can be thinned.

An optical head is constructed by mounting the light emitting / receiving element 1 having the composite element 2 and the objective lens driving device 8 on the optical stand 10 integrally formed with the reflection mirror 3 by the method described above.

The light emitting / receiving element 1 is fitted to the optical base 10 and fixed with an adhesive. The mounting positions of the light emitting / receiving element 1 in the X-axis, Y-axis, and Z-axis directions are defined by fitting with the optical base 10, and the light-receiving surface is installed so as to be located approximately in the middle of the focal points 21 and 22 of the light spot. To be done.

The objective lens driving device 8 holds the positioning hole 9a of the base 9 with an external chucking pin (not shown), adjusts the position and the angle to be described later, and then an adhesive (for example, UV adhesive). It is fixed to the optical table 10 at 31.

The light emitted from the semiconductor laser 1a of the light emitting / receiving element 1 is separated into a plurality of different light beams by the hologram element. A plurality of different light fluxes pass through the beam splitter 2a of the composite element 2, are reflected by the reflection mirror 3, and are fixed as the objective lens holder 6 by the objective lens 5 to form a light spot 37 having a diameter of about 1 micron on the information recording medium 7. Collected. Also, the beam splitter 2 of the composite element 2
The light flux reflected by a is incident on a laser monitor light receiving element (not shown) to control the drive current of the semiconductor laser 1a.

The reflected light from the information recording medium 7 follows the opposite path, is reflected and separated by the beam splitter 2a of the composite element 2, and is turned over by the folding mirror 2b and the polarization separation element 2c.
Incident on.

The polarization direction of the light emitted from the semiconductor laser 1a is set so as to be parallel to the paper surface in FIG. 14A, and the incident light incident on the polarization separation element 2c is polarized by the polarization separation element 2c. 2 components are orthogonal to each other
The light flux is separated into two light fluxes and is incident on the information signal light receiving area 18.

Of the reflected light from the information recording medium 7, the light beam that has passed through the beam splitter 2a is separated into a plurality of light beams by the hologram element and is focused on the focus error signal light receiving area 16 and the tracking error signal light receiving area 17. .

Focus servo is performed by the so-called SSD method, and tracking servo is performed by the so-called push-pull method.

Further, the main beam 14 composed of P-polarized light is used.
By calculating the difference between the main beam 15 composed of S-polarized light and S-polarized light, it is possible to detect the information signal of the information recording medium by the differential detection method. Furthermore, the pre-pit signal can be detected by taking the sum of them.

For adjusting the focus error signal and the tracking error signal, the positioning hole 9a of the base 9 is held by an external chucking pin (not shown) to define the position in the Z-axis direction, and then the objective lens driving device 8 is moved to the X position. Axial direction (radial direction) and Y-axis direction (tangential direction)
(See FIG. 12), and the output of the tracking error signal light receiving area 17 is adjusted to be substantially uniform. Further, in the adjustment of the relative inclination between the information recording medium 7 and the objective lens 5, similarly to the above, the base 9 is gripped by the external chucking pin (not shown), and the objective lens driving device 8 is moved in the radial direction (around the Y axis). ) The rotation is performed in the θR and the tangential direction (around the X axis) θT (see FIG. 12). After the above adjustment, the objective lens driving device 8 and the optical base 10 are bonded and fixed with the adhesive 31 (FIG. 13).
reference).

As described above, according to the third embodiment, by integrally molding the optical table 10 and the reflecting mirror 3, the step of positioning the reflecting mirror 3 with respect to the optical table 10 during the conventional optical head assembly adjustment, It is possible to eliminate a series of steps including a preload addition step and an adhesion step for the reflection mirror 3 on the optical table 10, and it is possible to significantly reduce costs by shortening the production tact.

Further, the positioning wall of the reflection mirror and the bonding reference surface, which are provided in the conventional optical bench, are unnecessary. Mold 40
If the reflection mirror fixing part is prepared with high accuracy, the reflection mirror 3 can be integrated with the optical table 10 with high accuracy. As a result, variations in the optical axis of the optical head are significantly reduced, and a highly accurate and stable optical head can be obtained at low cost.

Further, since no adhesive is used to fix the optical table 10 and the reflection mirror 3, the relative position shift and the relative angle between the optical table 10 and the reflection mirror 3 due to expansion / contraction when the temperature of the environment changes. It is possible to realize a highly reliable optical head that is excellent in environmental change characteristics and is less likely to cause misalignment.

Further, since it is not necessary to provide the optical mirror 10 with the positioning portion for the reflecting mirror 3 and the adhesive pool portion, the optical head can be greatly downsized and thinned.

In the above example, the first holding portions 45 of the optical table 10 holding the reflection mirror 3 are formed only on both sides of the reflection mirror 3 in the X-axis direction, and are not formed on both sides in the Z-axis direction. However, the first holding portion 45 can be formed so as to hold the entire circumference of the reflection mirror 3. In this case, the optical head is slightly thicker, but the holding power of the reflection mirror 3 is improved.

In the above example, the reflection mirror 3 is held by the first holding portion 45 and the second holding portion 46 of the optical table 10, but the opposite side surfaces (for example, the X-axis) are held. The reflection mirror 3 may be held by grooves (for example, grooves having a V-shaped cross section) formed on both side surfaces in the direction. In this case, the second holding unit that holds the reflection mirror 3 on the back surface is not necessary.

(Fourth Embodiment) Next, a fourth embodiment will be described with reference to FIG. FIG. 16 is an exploded perspective view showing the outline of the optical head according to the fourth embodiment. Members having the same functions as those in FIGS. 10 to 15 are designated by the same reference numerals, and detailed description thereof will be omitted.

The present embodiment differs from the third embodiment in the following two points. The first difference is that the resin material of the optical bench 10 is black and the amount of light reflection is reduced. Second
The difference is that the four corners of the reflecting surface 4 are covered with the first holding portions 45 so that the reflecting surface 4 of the reflecting mirror 3 having a substantially rectangular shape is exposed in a substantially circular shape or a substantially elliptical shape. The point is that the reflected light (stray light) from the four corners is greatly reduced.

According to the present embodiment, the light is reflected by the four corners of the reflecting surface 4, passes through the outside of the objective lens holder 6, is reflected by the information recording medium 7, and is reflected again on the light receiving surface of the multi-division photodetector 1b. So-called stray light that enters and gives an offset to the servo signal can be significantly reduced, and a higher performance optical head and disk recording / reproducing apparatus can be realized.

In the present embodiment, the exposed shape of the reflecting surface 4 by the first holding portion 45 is substantially circular or elliptical, but if the four corners of the reflecting surface 4 are covered with resin, The exposed shape of the reflecting surface 4 is not limited to this.

Further, in the present embodiment, in order to reduce the reflection of light at the four corners of the reflecting surface 4, the entire optical bench 10 including the first holding portion 45 covering the four corners is made of black resin. However, only the first holding portion 45 is made of black resin, and the optical base 1
The other part of 0 may be so-called two-color molding in which a resin having a different color is used. However, the effect of reducing stray light is greater when the entire optical base 10 is made of black resin. Further, the color of the resin is not limited to black as long as the amount of light reflection can be reduced, and may be another color.

Further, in place of or in addition to the color of the resin, such as black, which can reduce the amount of reflection, the surface is subjected to a surface treatment such as a satin treatment (for example, matting treatment), so that the light May be generated to reduce the stray light. The surface treatment is sufficient if it is applied to the surface of the first holding portion 45 that covers the four corners of the reflecting surface 4, but the optical bench 10
Stray light can be further reduced by performing similar processing on the other portions.

Further, the portion where the first holding portion 45 covers the reflecting surface 4 can be not only the four corners but also the entire circumference of the reflecting surface 4, whereby stray light can be further reduced.

(Fifth Embodiment) The fifth embodiment of the present invention will be described with reference to FIG. 17A and 17B are diagrams showing an outline of an optical stand including the light flux reflecting means of the fifth embodiment, FIG. 17A is a perspective view, and FIG. 17B is a sectional view in a plane including an optical axis. FIG. 17C is the same as FIG.
It is a partial expanded sectional view of the A section of (B). Members having the same functions as those in FIGS. 10 to 15 are designated by the same reference numerals, and detailed description thereof will be omitted.

The present embodiment differs from the third and fourth embodiments in that the light flux reflecting means is not used in the reflecting mirror 3 as in the third and fourth embodiments, but is combined with the resin molding of the optical table 10. This is a point in which the reflecting surface 54 is formed on the surface of the reflecting surface base 53 formed by molding. The reflective surface 54 is composed of a reflective film 55 on the surface of the reflective surface base 53 and an AR (anti-reflection) coating layer 56 thereon. Reflective film 5
5 is formed by evaporating aluminum, for example. However, the reflection film 55 is not limited to this, and may be a vapor deposition film such as chromium or a dielectric material as long as it is a vapor deposition film having excellent aberration characteristics of the reflected light flux. The AR coat layer 56 has an antioxidant function and an antireflection function. The AR coat layer 56 is formed by vapor deposition using, for example, silicon or magnesium fluoride as a material. Since the vapor deposition temperature of the reflective film 55 and the AR coat layer 56 is room temperature, the problem of performance deterioration of the light flux reflecting means due to vapor deposition does not occur.

According to this embodiment, since the reflecting surface base 53 is also molded at the same time when the optical table 10 is molded, the step of positioning the reflecting mirror 3 as in the third and fourth embodiments and the reflecting mirror 3 at the time of molding are performed. No need to preload. The reflecting surface base 53 is integrally formed of the same material as the optical table 10. As a result, the accuracy of forming the reflecting surface 54 is improved and stabilized. Further, environmental stability with respect to temperature changes is further improved, and a highly reliable optical head resistant to temperature environment changes can be realized. Further, since the reflection mirror holding section is not necessary, the optical head can be made thinner and smaller.

The resin material of the optical stand 10 is, for example, PPS.
(Polyphenylene sulfide) can be used, but is not limited thereto, and may be, for example, acrylic, polycarbonate, liquid crystal polymer, polyolefin resin, or other general resin.

The reflecting surface base 53 and the optical table 1 are also provided.
The other portions of 0 may be formed of a different resin material (so-called two-color molding). For example, the reflective surface base 53 may be formed of polycarbonate, acrylic, or polyolefin resin, and the other portions may be formed of PPS, liquid crystal polymer, or other general resin. Thereby, the surface smoothness of the reflecting surface 54 and the optical stand 10
It is possible to achieve both mechanical strength and

(Sixth Embodiment) Next, a sixth embodiment will be described with reference to FIG. 18A and 18B are diagrams showing an outline of an optical stand provided with the light flux reflecting means of the sixth embodiment. FIG. 18A is a perspective view and FIG. 18B is a surface including the optical axis of the light flux reflecting means. It is a partial expanded sectional view in. Members having the same functions as those in FIGS. 10 to 15 are designated by the same reference numerals, and detailed description thereof will be omitted.

The difference of the present embodiment from the fifth embodiment is that a light absorbing film 57 is formed on the AR coat layer 56 of the light flux reflecting means. The light absorption film 57 is shown in FIG.
As shown in (A), it is formed only at the four corners of the reflecting surface 54.

As the light absorption film 54, a well-known film can be used, but it can be formed by a method such as vapor deposition using a metal oxide such as tantalum oxide, chromium oxide or cobalt as a material.

According to the present embodiment, the light is reflected by the four corners of the reflecting surface 54, passes through the outside of the objective lens holder 6 and is reflected by the information recording medium 7, and again on the light receiving surface of the multi-division photodetector 1b. So-called stray light that enters and gives an offset to the servo signal can be significantly reduced, and a higher performance optical head and disk recording / reproducing apparatus can be realized.

(Seventh Embodiment) Next, a seventh embodiment will be described with reference to FIGS. 19 and 20 are exploded perspective views showing a schematic configuration of the optical head of the seventh embodiment, and FIG. 21 is a perspective view showing an adjusting method of the optical head of the seventh embodiment. Members having the same functions as those in FIGS. 10 to 15 are designated by the same reference numerals, and detailed description thereof will be omitted.

19 to 21, reference numeral 60 designates the objective lens holder 6 in the direction normal to the information recording medium 7 (plane wobbling direction).
And a suspension that movably supports in the radial direction,
Reference numeral 61 is a connecting portion for fixing the suspension 60 to the optical base 10, 61a is a positioning hole formed in the connecting portion 61, 62 is a yoke, 63 is an adhesive hole for adhesively fixing the yoke to the optical base 10, and 64 is The magnet 65 is a coil. The suspension 60 and the connecting portion 61 are integrally formed of a thin metal plate, and the objective lens holder 6 is displaced by elastically deforming the portion of the suspension 60. The objective lens holder 6, the suspension 60, the connecting portion 61, the yoke 62, the bonding hole 63, the magnet 64, and the coil 65 are all components of the objective lens driving device 8.

The difference of this embodiment from the third to sixth embodiments is that the optical table 10, the objective lens holder 6, the reflection mirror 3 and the suspension 60 are integrally molded. That is, the mold used for resin molding is the same as in the third embodiment.
In addition to the reflection mirror fixing portion described in Section 1, a suspension fixing portion is provided. Further, the mold is formed in such a shape that the objective lens holder 6 can be molded in addition to the optical table 10. Similar to the third embodiment, the reflection mirror 3 is installed in the mold, and the suspension 60 including the connecting portion 61 is installed in the mold. Suspension 60 has positioning holes 61
It is positioned in the mold using a. When molding resin is injected in this state, the reflection mirror 3, the suspension 60,
The objective lens holder 6 and the optical stand 10 can be integrally molded (FIG. 20). After that, the light emitting / receiving element 1 including the composite element 2, the yoke 62, the magnet 64, the coil 65, and the objective lens 5 are assembled to complete an optical head.

Adjustment of the optical head in this embodiment is performed as follows. As shown in FIG. 21, while the objective lens 5 is held at a prescribed height in the Z-axis direction by an external jig (not shown), position adjustment in the XY plane and θ
Adjust the tilt of the two axes in the T and θR directions. afterwards,
The objective lens 5 is adhesively fixed to the objective lens holder 6.

According to this embodiment, not only the reflecting mirror 3 but also the objective lens holder 6 and the suspension 60 are integrally formed when the optical table 10 is formed. Therefore, in addition to the effects of the third embodiment, The number of parts constituting the head and the number of assembly steps can be significantly reduced. As a result, a lower cost optical head can be provided.

In the seventh embodiment, although not shown, it is needless to say that a damper for resonance reduction may be provided in the suspension 60, and a damper such as gel can be used.

In the seventh embodiment, the reflecting mirror 3 is used as the light flux reflecting means, but as in the fifth embodiment, as shown in FIG. 22, the optical table 10 is used instead of the reflecting mirror 3.
The reflective surface base 53 is formed at the time of integrally molding
After that, the reflecting surface 54 may be formed on the surface of the reflecting surface base 53 by vapor deposition of aluminum or the like. With such a configuration, it is possible to reduce the cost by reducing the number of parts and the number of assembling steps and to improve the accuracy of the reflecting surface. Note that, in FIG. 22, the constituent elements are shown in an exploded manner so that the structure of the optical head thus obtained is easy to understand.

Further, in the seventh embodiment, the optical table 10, the reflecting mirror 3, the objective lens holder 6 and the suspension 6 are provided.
0 is integrally molded, but the optical base 10, the objective lens holder 6, and the suspension 60 are integrally molded, and then the optical base 1
It is also possible to bond and fix the reflection mirror to the reflection mirror attachment portion formed to 0. As a method for adhering and fixing the reflection mirror, a method of forming the adhering reference surface 128 and the positioning wall 129 on the optical table 10 as shown in the conventional example is also possible (FIG. 24).
It is more preferable to fix it by the method shown in Embodiments 1 and 2. Even with the former method, the cost can be reduced by reducing the number of parts, and with the latter method, the effects shown in the first and second embodiments can be obtained in addition to this.

Furthermore, in the seventh embodiment, the optical table 10, the reflecting mirror 3, the objective lens holder 6, and the suspension 6 are used.
0 and 1 were molded integrally, but in addition to these, the yoke 6
2, the magnet 64 and the coil 65 may be integrally molded. Further, the objective lens 5 may also be integrally molded.

In the seventh embodiment, the single resin material is used for the integral molding, but the optimum resin material is used for the constituent elements, for example, the materials of the optical stand 10 and the objective lens holder 6 are changed. It may be integrally molded.

The embodiments described above are all intended to clarify the technical contents of the present invention, and the present invention should not be construed as being limited to such specific examples. However, the present invention can be variously modified and implemented within the spirit of the invention and the scope described in the claims, and the present invention should be broadly interpreted.

[0124]

As described above, according to the first optical head and the method of manufacturing the same of the present invention, the reflection mirror is bonded and fixed to a predetermined position of the optical stand while being held by the mirror holding portion of the external jig. Therefore, the positioning wall and the bonding reference surface, which the conventional optical bench has, are not required. As a result, the optical head can be made smaller and thinner. Furthermore, if the mirror holding part of the external jig that is repeatedly used is processed with high accuracy, it is not necessary to have a high degree of molding accuracy or processing accuracy for the reflection mirror mounting part of the optical stand, so the dimensional accuracy of the optical stand is greatly increased. It is possible to reduce the cost, and the cost of the optical head can be reduced. In addition, the problem of destabilizing the quality of the optical head due to variations in the processing accuracy of the mirror mounting portion of the optical table is solved.

According to the second optical head of the present invention,
The optical bench is made by resin molding, and a resin or glass reflecting mirror is installed on the molding die. At this time, after strictly controlling the position and angle of the reflection mirror to be installed with respect to the mold, resin molding is performed to integrally form the optical stand and the reflection mirror. As a result, the adhesion reference plane and the positioning wall of the reflection mirror, which the conventional optical stand has, can be eliminated, so that the optical head can be made smaller and thinner. Further, it is not necessary to manage the molding accuracy or processing accuracy of the bonding reference surface of the reflection mirror and the positioning wall, which is included in the conventional optical table, so that the dimensional accuracy of the optical table can be significantly relaxed. At the same time, an optical head with high precision and stable quality can be obtained. Further, since the work of adhering and fixing the reflection mirror is unnecessary, the mass productivity of the optical head is improved and the cost can be reduced. Further, since the reflection mirror is integrally fixed and molded with the adhesive instead of fixing the reflection mirror to the optical table with an adhesive, the influence of expansion and contraction of the adhesive due to a change in temperature environment is eliminated. As a result, it is possible to significantly reduce the angle change and the position change of the reflection mirror, the change of the optical axis of the optical head becomes small, and it is possible to realize a highly reliable optical head having excellent environmental characteristics. .

Further, according to the third optical head of the present invention, the optical stand is made by resin molding, and the base portion of the light flux reflecting means is also molded at the time of resin molding. After forming, a reflection film is formed by metal vapor deposition or the like to complete the light flux reflecting means. That is, since the reflection mirror is not used, the reflection mirror is not cracked or chipped, and it is not necessary to consider in advance the dimensional margin due to the positioning error of the reflection mirror. Further, since the bonding reference surface and the positioning wall of the reflection mirror which the conventional optical stand has can be eliminated, the optical head can be made smaller and thinner. Further, since the positioning work and the adhesive fixing work of the reflection mirror are unnecessary, the mass productivity of the optical head is improved and the cost can be reduced. Also,
Since the base portion of the light flux reflecting means and the optical base are simultaneously molded as an integrated component, the influence of expansion and contraction of the adhesive due to changes in the temperature environment is eliminated. As a result, it is possible to significantly reduce the angle change and position change of the light flux reflecting means, reduce the optical axis change of the optical head, and realize a highly reliable optical head with excellent environmental characteristics. Become.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a method of attaching a reflection mirror to an optical bench according to the first embodiment of the present invention.
1A is a plan view, FIG. 1B is a cross-sectional view taken along the line II in FIG. 1A, and FIG. 1C is FIG.
FIG. 6 is a cross-sectional view taken along the line II-II as seen from the direction of the arrow.

2 is a partially enlarged view showing details of a mounting portion of the reflection mirror of FIG. 1, FIG. 2 (A) is a view seen from a direction perpendicular to a reflection surface of the reflection mirror, and FIG. 2 (B) is a view. II of 2 (A)
FIG. 3 is a cross-sectional view as seen from the direction of the arrow along the line I-III.

3A and 3B are partially enlarged views showing details of a mounting portion of the reflection mirror in FIG. 1, FIG. 3A is a view seen from an objective lens side, and FIG. 3B is IV in FIG. 3A. FIG. 4 is a cross-sectional view as seen from the direction of the arrow along the line IV.

FIG. 4 is an exploded perspective view showing a schematic configuration of the optical head according to the first embodiment of the present invention.

5A and 5B are optical path diagrams showing an optical path of the optical head according to the first embodiment of the invention, FIG. 5A being a front view and FIG.
(B) is a side view.

FIG. 6 is a signal circuit diagram showing a method of processing a signal obtained by the multi-division photodetector of the optical head according to the first embodiment of the present invention.

FIG. 7 is an exploded perspective view showing a method of adjusting the objective lens driving device and the optical base in the optical head according to the first embodiment of the present invention.

FIG. 8 is an overall perspective view of the optical head according to the first embodiment of the present invention.

FIG. 9 is a schematic view showing a method of attaching the reflection mirror to the optical bench according to the second embodiment of the present invention.
9A is a plan view, FIG. 9B is a sectional view taken along the line V-V in FIG. 9A, and FIG. 9C is a sectional view of FIG. 9A.
FIG. 6 is a sectional view taken along the line VI-VI as seen from the direction of the arrow.

FIG. 10 is an exploded perspective view showing a schematic configuration of an optical head according to a third embodiment of the present invention.

FIG. 11A shows a state immediately after the optical base and the reflection mirror are integrally molded in the third embodiment of the present invention.
FIG. 11B is a cross-sectional view taken along a plane including the optical axis, and FIG. 11B is an exploded perspective view showing a state in which the reflection mirror is separated to show the configuration of the optical bench after integrally molded.

FIG. 12 is an exploded perspective view showing a method of adjusting an objective lens driving device and an optical base in the optical head according to the third embodiment of the present invention.

FIG. 13 is an overall perspective view showing a completed state of an optical head according to a third embodiment of the present invention.

FIG. 14 is an optical path diagram showing an optical path of the optical head according to the third embodiment of the present invention, FIG. 14 (A) being a front view and FIG.
(B) is a side view.

FIG. 15 is a signal circuit diagram showing a method of processing a signal obtained by the multi-segment photodetector of the optical head according to the third embodiment of the present invention.

FIG. 16 is an exploded perspective view schematically showing an optical head according to a fourth embodiment of the present invention.

17A and 17B are diagrams showing an outline of an optical bench provided with a light flux reflecting means according to a fifth embodiment of the present invention. FIG. 17A is a perspective view and FIG. 17B is a plane including an optical axis. A cross-sectional view and FIG. 17C are partially enlarged cross-sectional views of a portion A of FIG. 17B.

18A and 18B are diagrams showing an outline of an optical bench provided with a light flux reflecting means according to a sixth embodiment of the present invention. FIG. 18A is a perspective view and FIG. 18B is an optical axis of the light flux reflecting means. It is a partial expanded sectional view in the surface containing.

FIG. 19 is an exploded perspective view showing a schematic configuration of an optical head according to a seventh embodiment of the present invention.

FIG. 20 is an exploded perspective view showing a schematic configuration of an optical head according to a seventh embodiment of the present invention.

FIG. 21 is a perspective view showing a method for adjusting an optical head according to a seventh embodiment of the present invention.

FIG. 22 is an exploded perspective view showing a schematic configuration of an optical head having another configuration according to the seventh embodiment of the present invention.

FIG. 23 is an exploded perspective view showing a schematic configuration of a conventional optical head.

24 is an enlarged cross-sectional view showing a method of fixing the reflection mirror of the optical head of FIG. 23.

FIG. 25 (A) is an optical path diagram showing the optical path of the optical head of FIG. 23, and FIG. 25 (B) is a plan view showing the light receiving area and the light spot of the light receiving surface of the multi-segment photodetector. is there.

26 is a signal circuit diagram showing a method of processing a signal obtained by the multi-segment photodetector of the optical head of FIG.

[Explanation of symbols]

1 Light emitting / receiving element 1a Semiconductor laser 1b Multi-split photodetector 2 composite elements 2a beam splitter 2b folding mirror 2c Polarization separation element 3 reflection mirror 4 Reflective surface 5 Objective lens 6 Objective lens holder 7 Information recording medium 8 Objective lens drive 9 base 9a Positioning hole 10 Optical stand 11 Reference plane 12, 13 light spots 14 Main beam (P polarized) 15 Main beam (S polarization) 16 Focus error signal light receiving area 17 Tracking error signal receiving area 18 Information signal receiving area 19 Subtractor 20 adder 21, 22 Focus of light spot 23 Positioning hole 24 External jig 25 Adhesion reference plane 26 Adhesion pool 27 Positioning pin 28 Positioning wall 29 UV adhesive 30 optical axes 31 Adhesive 32 guide shaft 35 Positioning wall 37 light spots 40 Resin Mold 41 Reference plane for reflective mirror 42 Positioning Wall for Reflecting Mirror 43,44 preload 45 First holding unit 46 Second holding unit 51,52,53 preload 53 Reflective surface base 54 Reflective surface 55 Reflective film 56 AR coat layer 57 Light absorbing film 60 suspension 61 Connection 61a Positioning hole 62 York 63 Bonding hole 64 magnet 65 coils 101 Semiconductor laser 102 collimating lens 103 diffraction grating 104 composite element 104a beam splitter 104b Polarization separation element 104c folding mirror 105 Objective lens 106 information recording medium 107 Light receiving element for monitor 108 Convex lens 109 concave cylindrical lens 110 holding member 111 Multi-division photodetector 112,113 Focus of light spot 114 Main beam (P polarized) 115 Main beam (S polarization) 116 Main beam (P + S polarization) 117 Light spot by preceding beam 118 Light spot by trailing beam 119 4-division light receiving area 120 preceding beam receiving area 121 Trailing beam receiving area 122a, 122b Information signal receiving area 123 Subtractor 124 adder 125 optical table 126 reflection mirror 127,128 Adhesion reference surface 129 Positioning wall 130 Adhesion pool 131 UV adhesive 132 Objective lens driving device

Front page continued (72) Inventor Kenichi Miyamori 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Takuya Wada, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (56 ) References JP-A-11-339299 (JP, A) JP-A-4-349221 (JP, A) JP-A-7-201064 (JP, A) JP-A-5-135404 (JP, A) JP-A-5-135404 (JP, A) 5-314535 (JP, A) JP-A-7-6533 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 7/22 G11B 7/135

Claims (13)

(57) [Claims] 1. An optical head having a light source, an objective lens, a reflection mirror for reflecting a light beam from the light source to enter the objective lens, and an optical stand for holding the light source and the reflection mirror. In the method, the reflection mirror and the optical stand are mounted on an external jig that includes a mirror holding portion that holds the reflection mirror and positioning walls that are provided so as to face each other in the horizontal direction of the mirror holding portion. When installing and adhering the reflection mirror and the optical bench, the side surface of the reflection mirror is brought into contact with the positioning wall of the external jig, and the reflection surface of the reflection mirror is an angle reference surface of the mirror holding portion. The reflective mirror and the optical stand by adhering and fixing the adhesive between the side surface provided on the optical stand and the side surface of the reflecting mirror opposite to the side surface in a state of being brought into contact with the reflecting mirror. An optical head manufacturing method characterized by the above. 2. The method of manufacturing an optical head according to claim 1, wherein an adhesive reservoir provided near the center of two opposing side surfaces provided on the optical bench is filled with an adhesive and fixed by adhesion. 3. The method of manufacturing an optical head according to claim 1, wherein the reflection mirror has a flat plate shape. 4. The method of manufacturing an optical head according to claim 1, wherein the optical head is bonded and fixed using a UV adhesive. 5. A light source, an objective lens that forms a light spot on an information recording medium, and a light beam that is located between the objective lens and the light source, reflects a light beam from the light source, and causes the light beam to enter the objective lens. A method of manufacturing an optical head comprising a reflection means and a resin optical stand for holding the light source, wherein the light flux reflection means is a reflection in which a reflection film is formed on a base material having a softening point of 500 ° C. or higher. 200 ° C.-400, which is a mirror and has the light flux reflecting means installed in a molding die having a fixing portion for holding the light flux reflecting means.
A method of manufacturing an optical head, characterized in that the light flux reflecting means and the resin optical base are integrally molded by resin molding at a temperature of ° C. 6. A resin molding is performed while a suspension that supports a lens holder that holds the objective lens so as to be movable in a normal direction and a radial direction of an information recording medium is installed in the molding die. The method of manufacturing an optical head according to claim 5 , wherein the light flux reflecting means, the suspension, the lens holder, and the resin optical stand are integrally molded. 7. The light flux reflecting means is held on the resin optical base on the back surface and in the vicinity of two end surfaces in the direction parallel to the front surface of the information recording medium, and the light beam reflecting means is located in the direction normal to the information recording medium.
Method of manufacturing an optical head according to claim 5 or 6 One of the not retained in the vicinity of the facet. 8. substantially four corners of the reflecting surface of the beam reflecting means is covered with a resin of substantially black, the manufacture of the optical head according to claim 5 or 6 reflection amount of substantially four corners is reduced Method. Substantially four corners of the reflective surface of claim 9, wherein said light beam reflecting means is covered with a resin, the surface of the resin covering the substantially square of the optical head according to claim 5 or 6 is satin finish Production method. Wherein said reflective film according to claim 5 or is a metal film or a dielectric film containing aluminum or chromium material
7. The method for manufacturing an optical head according to item 6 . 11. An AR coat having an antioxidation function and an antireflection function is provided on the reflective film.
7. The method of manufacturing the optical head according to 5 or 6 . 12. The resin optical stand is made of acrylic or PP.
S, polycarbonate, liquid crystal polymer, or a manufacturing method of the optical head according to claim 5 or 6 comprising a polyolefin resin. 13. and the light absorbing film is applied to substantially four corners of the reflecting surface of the light beam reflecting means, the manufacturing method of the optical head according to claim 5 or 6 reflection amount of substantially four corners is reduced .