JP2001093185A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize and lighten the detection mechanism of magneto-optical signals and to improve the mounting efficiency of the entire device in an optical pickup for reading the magneto-optical signals recorded on a magneto-optical recording medium and writing the signals onto the recording medium. SOLUTION: This device is provided with a semiconductor laser, a hologram for transmitting and diffracting emitted light from the semiconductor laser, an objective lens for converging the emitted light onto a medium surface and a polarized light separation element for separating return reflected light reflected on the medium surface into two directions. While one of the separated reflected light is separated further and converged to a first detector to detect the magneto-optical signals, the other reflected light is diffracted by the hologram and converged to a second detector to detect servo signals. The hologram and the second detector are turned to the composite element of an integrated structure, the composite element and a holding member to which the semiconductor laser of a light source is force-fitted are made to parallelly face each other, the detection mechanism is made into a unit structure and the condensation of components and miniaturization are realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical pickup used for an optical disk device.

[0002]

2. Description of the Related Art Conventionally, an optical disk device has been widely used for a computer peripheral device, an optical communication device and the like, which are devices to which a semiconductor laser is applied. A semiconductor laser diode (LD) is used as a laser light source for writing and reading signals to and from a recording medium. An optical pickup including an optical element for collecting, separating, and detecting laser light, a detector, and an LD is called an optical pickup.

[0003] In recent years, an optical disk device is mounted in a personal computer (PC), and a device capable of handling a large-capacity recording medium has been developed. Notebook PC
In consideration of mounting on optical discs, optical disc apparatuses are required to be smaller and to save power. On the other hand, in order to effectively use the space in the optical disk device, it is necessary to reduce the weight and size of the optical components used.

FIG. 8 shows a configuration diagram of a conventional optical pickup using a hologram as an example of an optical system used in an optical disk device. This is a configuration in which signal light for detecting a tracking signal and a focusing signal is separated by a hologram, and the functions are integrated. In the figure, a laser beam emitted by a semiconductor laser diode 1 (LD) spreads at a certain angle, passes through a hologram 21, and is corrected to a parallel beam by a collimating lens 3 (CL). Further, the polarization beam splitter 4
(PBS) and passes through the objective lens 5 to the recording medium 6
Is focused on the surface of the. The reflected light reflected from the surface of the recording medium 6 passes through the objective lens 5, is split into two by a polarizing beam splitter 4 (PBS), and is further diffracted and separated by a polarization splitting element 7 (Wollaston prism). The light passes through the condenser lens 8 and is detected by the first light receiving element 9 as an optical signal.

On the other hand, a polarizing beam splitter 4 (PBS)
The reflected light that has passed through reaches the hologram 21 via the collimating lens 3 (CL). Here, a part of the laser beam is diffracted and condensed on the light receiving element 23 (PD) divided into four regions of two regions for diffracting the tracking signal component and two regions for diffracting the focusing signal component. , A tracking signal and a focusing signal are detected. On the other hand, the hologram 21 and the semiconductor laser diode 1
(LD), the reflecting prism 24b and the light receiving element 23 (P
The detection mechanism section composed of each element of D) is a base section 40.
Has a structure in which these elements are arranged on the same plane. As a result, the light source light emitted from the semiconductor laser diode 1 (LD) emitted in parallel with the base portion 40 can be totally reflected by the reflection prism 24b and incident on the hologram 21. The hologram 21 transmits the light from the light source and diffracts the reflected light from the recording medium 6 so as to enter the light receiving element 23 (PD).

As described above, the semiconductor laser diode 1 (LD) and the reflecting prism 24b, and the light receiving element 23 (PD) and the hologram 2 are provided on the same surface of the base portion 40.
1 is also packaged to realize the integration and miniaturization of components.

[0007]

However, in the above-mentioned optical system, the silicon crystal, which is the material of the light receiving element (PD), has a lower thermal conductivity than metal, so that the semiconductor laser diode 1 (LD) chip It has been difficult to efficiently radiate the generated heat. Also, electrically light receiving element (PD)
The necessity of insulating the back surface requires an insulating plate, which further hinders heat dissipation. Also, assembly and
As a failure that occurs during mounting, the semiconductor laser diode 1
(LD) chip destruction, light receiving element (PD) wiring disconnection,
Poor capping may occur. Since it is confirmed by a test after completion, if a defective product comes out, the entire integrated portion is discarded. In this case, parts cannot be reused, and it is difficult to improve the yield.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a low-cost optical pickup in which optical signal detection mechanisms are compact and integrated, and have high signal quality, high yield and high yield.

[0009]

The present invention employs the following means to solve the above problems.

FIG. 1 shows a basic configuration diagram of the present invention.

Basically, a light source (laser light) for irradiating the recording surface of the optical recording medium with light, a correcting means (CL) for converting the spread laser light into parallel light, and a recording means for recording the parallel light. The optical system is composed of light collecting means (objective lens) for collecting light on a medium. Further, in order to extract a magneto-optical signal from the reflected light including the signal from the recording medium, a polarizing beam splitter (PBS) as a second separating means is provided between the focusing means (objective lens) and the correcting means (CL). And a polarization separation element (Wollaston prism: W
P), and a first light receiving unit (PD1) is disposed thereon.
In order to detect a servo signal composed of a tracking signal and a focusing signal, a diffraction unit (hologram) integrated with a second light receiving unit (PD2) is provided between the correction unit (CL) and the light source (LD). Is used.

That is, an optical pickup device according to the present invention is an optical pickup device which performs at least one of reading out a magneto-optical signal recorded on an optical recording medium and writing on the optical recording medium. A light source that irradiates light on the recording surface of the optical recording medium, a light receiving unit that receives light reflected on the recording surface of the optical recording medium, detects a servo signal of a tracking signal and a focusing signal, and transmits light from the light source. A detection mechanism having a unit structure of a diffraction means for diffracting the light reflected by the optical recording medium and making the light incident on the light receiving means, wherein the detection mechanism is constituted by integrating the light receiving means and the diffraction means into an integral structure. An element and an opening penetrating through a central portion of a metal block having both end faces are provided, and a reflection surface having a mirror-finished surface is provided in a peripheral area of the opening on one end face, and A light source holding member for press-fitting and installing the light source from the mouth, and a spacer member for disposing the composite element and the light source holding member so as to face each other at a predetermined interval in parallel and to provide a space for blocking external light inside. (Corresponding to claim 1). By employing this structure, a light-emitting element and a light-receiving element are separately manufactured, and a high yield can be obtained by combining them. Therefore, there is an effect that the possibility of generating a defective product is lower than in the case of integrally manufacturing. In addition, by electrically and thermally separating the light emitting element and the light receiving element, a stable signal can be obtained and high reliability can be obtained.

Alternatively, it is also possible to integrally form a shape corresponding to the spacer member on the light source holding member and omit the spacer member of the detection mechanism in the first aspect (corresponding to the second aspect). ). By adopting this configuration,
A light-emitting element and a light-receiving element are separately manufactured, and a high yield can be obtained by combining the light-emitting element and the light-receiving element. By electrically and thermally separating the light-receiving element and the light-receiving element, a stable signal can be obtained and high reliability can be obtained. In addition to the effects of claim 1, the number of parts can be further reduced. This has the effect of enabling cost reduction.

Next, as a first embodiment of the composite device, at least two or more light receiving elements are provided inside a substrate formed of a transparent resin, and a central region between the two or more light receiving elements is provided. The light receiving element has a structure in which diffraction means is provided on the resin surface on the light receiving surface side (corresponding to claim 3). By doing so, the second light receiving section (PD2)
And the diffraction means (hologram) can be integrated into a single structure, which reduces costs and facilitates optical adjustment. That is, the second light receiving unit (PD2) is manufactured by arranging a Si chip with high precision on a material constituting the wiring, wiring the Si chip terminal and the wiring, and then enclosing the wiring with an optical resin. . Further, since a diffractive means (hologram) is formed on the surface at the same time as the resin is enclosed, the number of steps and materials can be reduced, and the element can be manufactured with high accuracy.

As a second mode of the composite device, a diffractive means is provided on the surface of a transparent glass substrate, at least two or more light receiving elements are provided on the same surface as the diffractive means, and the same as the window material inside the light source. An optical adhesive having a refractive index and a structure in which the light receiving surface side of the light receiving element is adhered to the glass substrate surface at the same thickness as the window material (corresponding to claim 5), thereby facilitating fabrication. The effect is as follows. Further, the reflection member has a structure in which a reflection coating is applied to one end surface side of transparent glass, and the reflection coating surface is provided on the light path of the opening of the light source holding member, and the reflection coating surface is provided facing the light receiving element side. (Corresponding to claim 5), there is no wiring such as wiring, so that the tact time can be reduced and the effect of contributing to cost reduction is produced.

Further, as a third embodiment of the composite device, the composite device is constituted by a metal substrate having an opening in a central region, a diffractive means is provided on one end side of the opening, and at least two or more light receiving elements are used. The light receiving element is configured so as to have a structure in which the light receiving surface of the light receiving element is directed outward in a peripheral region of the opening on the end face side (corresponding to claim 6). In addition, the reflecting member has a structure in which a reflecting coating is applied to one end surface side of transparent glass, and the reflection coating is attached to the light source holding member on the optical path of the opening of the light source holding member, and the reflective coating is attached to the light source holding member. (Corresponding to claim 6). By doing so, the optical path can be made equal, and the aberration at the converging spot on the light receiving element can be reduced. Further, it is possible to reduce the influence of the chromatic aberration of the optical material.
As a result, the quality of the obtained signal is improved.

Further, the following three measures are implemented as measures against stray light.

That is, the connection between the terminal of the light receiving element built in the composite element and the external terminal is wired by a conductive pattern, and this wiring pattern is formed in a central region between at least two or more light receiving elements. In addition, the wiring is arranged in a region avoiding the optical path passing through the diffraction means provided on the resin surface on the light receiving surface side of the light receiving element (corresponding to claim 3).

Also, the surface of the light source holding member is formed as a mirror surface treatment capable of reflecting light, and the inside of the spacer member is configured to have a characteristic of absorbing light (corresponding to claim 4). By doing so, there is an effect that the number of parts can be reduced and the cost can be reduced. Furthermore, the surface of the light source holding member that is in contact with the reflecting member is configured to have a characteristic of absorbing light (corresponding to claim 7). Further, the light source light emitted from the light source is directly transmitted to the second light receiving unit (PD
In order to avoid entering 2), it is effective means to form an aperture on the reflection member. By doing so, stray light can be reduced, so that signal quality is improved.

Next, in the optical system shown in FIG. 1, the servo signal light is diffracted by the diffraction means (hologram), reflected once by the reflection member, and then passes through the base material of the diffraction means (hologram) to form the second signal light. The light is focused on the light receiving unit (PD2). Usually, in a pseudo-confocal optical system using a diffractive means (hologram), a configuration is adopted in which the focal position of the diffracted light is adjusted to be substantially the same as the focal position of the light source. Therefore, a pseudo-confocal optical system equivalent to the case where there is no reflecting surface is formed by arranging optically symmetrically with respect to the reflecting surface. In this case, the refractive index and the thickness of the member through which the signal light is transmitted after the reflection are substantially the same as those of the member through which the light source laser light is transmitted on the outward path.

That is, according to the present invention, the optical path length between the signal light separated by the signal light separating element and the light receiving element is equal to the optical path length between the signal light separating element and the light source. The optical member constituting each element is configured to have a structure in which the refractive index and the thickness are adjusted (corresponding to claim 8). By doing so, it is possible to minimize the amount of light generated at the condensing position of the signal light, to make the optical path the same, and to prevent the quality of the servo signal from deteriorating.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION In order to more specifically show the effects of the present invention, examples will be given below. Embodiment (1) FIG. 2 shows an optical pickup device of the present invention as Embodiment 1.

In this embodiment, the semiconductor laser diode 1
(LD), an optical pickup having a reflecting member 24, a composite element 2, a collimating lens 3 (CL), a polarizing beam splitter 4 (PBS), a Wollaston prism 7 (WP), a first light receiving element 9, and an objective lens 5. Is composed. The semiconductor laser diode 1 (LD) has a center oscillation wavelength of 685.
nm, a divergence angle of about 20 degrees, and a CAN type is used. By using the CAN type, cost reduction by mass production effect can be realized.

Further, the semiconductor laser diode 1 (LD) of the CAN type is made of aluminum having good heat conductivity by using the LD holding member 1.
It is fixed by press-fitting to 1. By doing so, the problem of heat dissipation can be solved.

As described above, the material of the LD holding member 11 is preferably aluminum in consideration of thermal conductivity and cost.
The outer shape is made by casting, and the semiconductor laser diode 1
The part for press-fitting the (LD) and the part for fixing the reflection member 24 are cut.

FIG. 4 shows the structure of the reflection member 24 and the patterning shape of the reflection surface. Regarding the reflection member 24, if a mirror surface portion is formed on the surface of the LD holding member 11 and the reflection member 24 is integrated to form the reflection surface 25, the number of components can be reduced, which is an advantageous configuration. However, in this case, it is necessary to pay attention to the oxidation and corrosion of the Al surface, and it is important to provide an antioxidant layer under the reflective layer. An Au film is formed as a reflective film by sputtering, and an MgF film is provided on the surface for protection. Black paint is convenient for stray light control.

As another example, it is possible to fabricate the reflection member 24 by patterning a reflection film on the surface of a substrate made of a transparent material. A glass substrate (BK7) is used as a material. However, a circular opening pattern (aperture) is provided at the center to transmit the light source light on the outward path, and an AR coating is applied to the portion. A dielectric multilayer film is used as a material of the reflection film. A as a metal film
A u film is also possible. In order to prevent extra diffused light from the LD, the opening pattern is preferably formed on the back surface of the reflection member 24, that is, on the LD side. However, if the reflection pattern and the opening pattern are formed on the same surface, the number of steps can be reduced and an advantageous structure can be obtained.

As another example, the reflection member 24 can be made of a material that does not transmit light. in this case,
The transmitted light from the light source may be emitted through a hole provided in the reflecting member 24, for example, a circular space, and the signal light from the hologram 21 may be reflected by a mirror-finished surface. By forming a reflective surface on the surface with a dielectric multilayer film or an Au film and patterning it, stray light can be prevented from going to the light receiving element.

A low-viscosity, fast-curing UV-curable adhesive is used for the portion where the LD holding member 11 and the reflecting member 24 are bonded. In this case, the surface of the LD holding member 11 is subjected to black alumite treatment for the purpose of preventing and absorbing stray light. In addition, an adhesive having a property of absorbing light or an adhesive mixed with fine particles may be used.

FIG. 3 shows an example of a composite element in which the hologram 21 and the second light receiving element 22 (PD2) are integrated.

A wiring is produced by patterning a thin metal plate, and a second light receiving element 22 (PD2) is fixed thereon. The periphery of the second light receiving element 22 (PD2) has a structure embedded with a substance transparent to laser light from the semiconductor laser diode 1 (LD) as a light source, and a hologram 21 is formed on the surface thereof. I have. The wiring is provided with a space for transmitting the transmitted light from the light source. However, the space is filled with the above-mentioned transparent substance, and has an optically specular surface state. In this embodiment, for example, an amorphous polyolefin-based resin (product name: ZONEX) is employed as the transparent substance. In constructing the pseudo-confocal optical system, the optical path length from the hologram 21 needs to be equal to the optical path length to the semiconductor laser diode 1 (LD). ) And the hologram 21
The thickness from the surface to the light receiving surface is also the thickness of the combination of the reflection member 24 and the window material. Even when materials having different refractive indices are used, there is no problem in receiving signal light as long as the optical path lengths are equal.

As a method for manufacturing the composite element 2, a molding method using plastic as a material is employed. The pattern shape of the hologram 21 is transferred to a mold, and a composite element can be manufactured with a high yield while securing the positional accuracy with the second light receiving element 22 (PD2).

When the reflecting member 24 is formed of an optically flat substrate, the surface in contact with the LD holding member 11 has been subjected to a surface treatment for absorbing light scattered inside. Alternatively, when the reflection member 24 is bonded to the LD holding member 11, the adhesive may have a property of absorbing light.

The surface of the LD holding member 11 is mirror-finished, patterned so as to reflect only the diffracted light from the hologram 21, and the other surface is subjected to a light absorbing surface treatment. It can also be 25. In this case, on the semiconductor laser diode 1 (LD) side on the back surface,
An aperture is configured to limit excess spread light from the semiconductor laser diode 1 (LD). The semiconductor laser diode 1 (LD) adopts a CAN package, and is fixed by being press-fitted into the LD holding member 11. The LD holding member 11 uses an aluminum plate as a metal material.

FIG. 5 shows a manufacturing process of the composite device 2.

The structure of the composite device 2 is such that a metal thin plate is patterned to form a wiring portion, and a Si chip as a light receiving device is soldered to the surface thereof. After wiring each terminal on the Si chip and the wiring portion, a resin is poured in, and a hologram of the outer shape and the surface is manufactured by a molding method. The wiring part is a semiconductor laser diode 1 (L
A space is provided for transmitting the laser light from D) and the signal light from the recording medium 6. Usually, the resin enters into the mold during molding, and thus the manufacturing process is performed by backing a mirror-finished ceramic substrate on the back surface of the thin metal plate. Thereby, when peeled off from the substrate, an optical plane can be maintained. Finally, after both sides are coated with an AR coat, they are cut out by dicing. Through the above steps, the composite device 2 can be efficiently mass-produced.

The hologram 21 has a pattern divided into four for diffracting the tracking signal and the focusing signal. On the outward path, the laser light is transmitted with a 0th-order diffraction efficiency of 80%, and on the return path, the signal light is diffracted with a first-order diffraction efficiency of 9% and guided on the PD. The front and back surfaces are provided with an AR coating, so that the coating has little loss with respect to oblique incident light. Considering that the collimator lens 3 (CL) and the objective lens 5 are lightweight, plastic lenses are used. In addition, a glass material can be used. In the polarization beam splitter 4 (PBS), the transmittance of the P-polarized light, which is the same as that of the semiconductor laser diode 1 (LD) as the light source, is 85% in the characteristics of the polarization separation film.
The reflectance of S-polarized light, which is the same as the magneto-optical signal, is 97% or more.

Polarization separation element 7 (Wollaston prism:
Regarding WP), the crystal axis of the birefringent crystal as the material has an angle of 45 degrees with respect to the P polarization direction of the semiconductor laser diode 1 (LD) as the light source. The polarizing beam splitter 7 (Wollaston prism: WP) is formed by bonding two prisms whose crystal axes are perpendicular to each other. A condenser lens 8 is added to the surface.

The first light receiving element 9 has a light receiving surface divided into two so as to receive two light beams separated by the polarization separating element 7 (Wollaston prism: WP). The element itself is packaged with a transparent resin. Second Embodiment FIG. 6 shows a detailed structure of a composite device 2 in which a wiring process on a second light receiving unit (PD2) is simplified as a second embodiment.

The composite element 2 in this embodiment is configured such that the light receiving surface of the second light receiving element 22 and the hologram 21 are located on substantially the same plane. In the figure, a hologram 21 is formed on a glass substrate, and a wiring pattern is further added on its surface. The second light receiving unit 22 (PD
The light receiving surface of the Si chip 2) is arranged so as to face the diffraction surface of the hologram 21.

The hologram 21 uses a glass substrate (BK7) as an optical material having heat resistance.
A surface relief hologram is produced by E (Reactive Ion Etching). Further, after the metal film is sputtered, only a necessary portion is patterned and removed to form a wiring portion. The Si chip, which is the second light receiving element 22, is positioned so that the signal terminal portion and the wiring portion are in contact with each other, and are electrically connected. For example, it is possible to apply solder plating to the wiring portion in advance, position the Si chip, and then heat it to obtain an electrical connection and fix it. Since the wiring is exposed, wiring to an external circuit is easy, and a major feature is that the step of wiring the Si chip is eliminated. Also, the LD holding member 11 made of metal and having the same electric potential as GND is brought into contact with a glass substrate which is an insulating material and is bonded to the LD holding member 11 to electrically separate a signal from the PD. I have.

The surface of the LD holding member 11 is mirror-finished, and a reflection film is applied to a portion for reflecting signal light, and an absorption film is provided for other portions to prevent stray light, thereby reducing the number of parts and reducing costs. Becomes possible.

Since the signal light is required to be optically symmetric on the reflection surface, the reflection member and the substrate of the LD window material are made of the same material and have the same thickness as the diffraction means (hologram) substrate. I'm trying. However, in order to fix the Si chip on the diffraction means (hologram), an optical adhesive having a refractive index and a thickness substantially equal to those of the window material of the LD is used. Thereby, an optical path corresponding to the window material of the LD is created, and the aberration generated in the signal light can be reduced.
From the above configuration, the wiring process can be simplified. Third Embodiment FIG. 7 shows a detailed structure of a composite element 2 having another shape and advantages of the present invention as a third embodiment.

The structure of the composite element 2 in this embodiment is configured such that the light receiving surface of the second light receiving element 22 is located closer to the light source than the diffraction surface of the hologram 21.

The hologram substrate is formed by a duplication method (2P method) using an ultraviolet curing resin (photopolymer) or
It is produced by a molding method using glass or resin, and is cut into a predetermined size by dicing. After positioning the light receiving element substrate, it is fixed to the back surface with an ultraviolet adhesive.

The second light receiving section (PD2) itself is fixed on the substrate with solder or adhesive. Electrodes are provided on the substrate, and wiring is performed from the second light receiving portion (PD2) to the wiring portion. The electrodes have a shape penetrating the substrate and are connected to external terminals. The diffracting means (hologram) adheres to the back surface of the substrate with respect to the second light receiving section (PD2). Therefore, the second light receiving unit (P
The substrate of D2) is provided with holes for transmitting light.

As shown in FIG. 7, the light receiving element portion is formed on a substrate having a space through which the laser light on the outward path and the signal light on the return path can pass. Since the metal substrate is used, the processing of the space portion is easy by press working, it can be manufactured at low cost, and an advantageous structure can be obtained since it has heat resistance to soldering.

Since the second light receiving element 22 (PD 2) is located inside, connection to an external circuit requires an insulated terminal. At the same time, it is necessary to wire the Si chip and the terminal. The insulation from the LD holding member 11 fixes the composite element 2 with an adhesive having no conductivity. Alternatively, a method of insulating the end of the composite element 2 may be used. Alternatively, the PD, the semiconductor laser diode 1
(LD) and insulation.

The material and thickness of the reflecting member 24 are the same as those of the window material of the light source (LD), provided that the optical path length is the same. However, regarding the reflecting surface, the semiconductor laser diode 1 (L
D) Place it on the side. That is, when viewed from the signal light, a configuration is adopted in which the light once passes through the reflecting member 24 and is reflected on the back surface. At the same time, the aperture portion is formed on the pattern surface of the reflection surface. Optically, it has a reflecting surface on the side of the semiconductor laser diode 1 (LD) as a light source, and can be manufactured in the same process as the opening pattern portion.

From the relation of optical aberration, the signal light needs to be transmitted through the reflecting member 24. Therefore, the LD holding member 11
It is also possible to adopt a configuration in which a reflection surface is formed on the surface of the light source and signal light only passes through the reflection member 24. In this case, the reflective member 24 is subjected to AR coating on both sides. Further, the opening restriction is performed at the opening provided in the LD holding member 11. Therefore, there is no need for positioning,
The structure becomes easy.

By having the above structure, the light source (L
D) and the signal detection portion can be further miniaturized.

[0052]

As described above, according to the present invention, the second light receiving element 22 (PD2) and the hologram 21
The light source and the servo signal detection are facilitated and the pickup optical system is simplified by integrating the composite element 2 in which is integrated with the reflection member 24, the LD holding member 11, and the semiconductor laser diode 1 (LD). ing.

Thus, the semiconductor laser diode 1
(LD) facilitates heat dissipation, enables a stable writing operation, and reduces stray light components mixed into the servo signal, thereby improving the quality of the servo signal and enabling stable control. Further, by manufacturing the composite element 2, the optical axis adjustment becomes easy, and the tact time can be reduced. Also, since the optical system can be simplified, a low-cost optical pickup can be provided.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is an optical pickup of the present invention (Example 1).

FIG. 3 shows a composite device structure of the present invention (Example 1).

FIG. 4 shows the structure of the reflecting member and the patterning shape of the reflecting surface.

FIG. 5 is a manufacturing process of a composite device.

FIG. 6 shows a composite element structure of the present invention (Example 2).

FIG. 7 shows a composite element structure according to the present invention (Example 3).

FIG. 8 shows a conventional optical pickup.

[Explanation of symbols]

 1: Semiconductor laser diode (LD) 2: Composite element 3: Collimating lens 4: Polarization beam splitter (PBS) 5: Objective lens 6: Recording medium 7: Polarization separation element (Wollaston prism) 8: Condensing lens 9: First light receiving element 11: LD holding member 21: Hologram 22: Second light receiving element 23: Light receiving element 24: Reflecting member 24b: Reflecting prism 25: Reflecting surface 26: Light absorbing film 30: Electrode 31: Metal film 32: Mirror surface ceramic substrate 33: Resin 34: Mold 40: Base part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 11/105 551 G11B 11/105 551N 551S 551L 556 556A F term (Reference) 5D075 CD01 CD06 CD16 CD19 5D118 AA01 BA01 BB06 CD02 CD03 CF15 DA20 5D119 AA01 AA40 BA01 EA02 EA03 FA30 JA22 JA23 JA57 KA04 NA05

Claims (8)

[Claims] 1. An optical pickup device for reading out a magneto-optical signal recorded on an optical recording medium or writing on an optical recording medium, irradiating light on a recording surface of the optical recording medium. A light source; light receiving means for receiving light reflected on the recording surface of the optical recording medium and detecting a servo signal of a tracking signal and a focusing signal; and light transmitted through the light source and reflected by the optical recording medium A detection mechanism having a diffractive means for diffracting the light and entering the light-receiving means, and a detection mechanism having a unit structure. The detection mechanism comprises a composite element in which the light-receiving means and the diffraction means are integrally formed, and a metal having both end faces. An opening that penetrates the center of the block is provided, a reflection surface whose surface is mirror-finished is provided in the peripheral area of the opening on one end, and a light source is pressed and installed through the opening on the other end. And a spacer member in which the composite element and the light source holding member are opposed to each other at a predetermined interval and arranged in parallel, and a spacer member is provided inside the space so as to block external light. Optical pickup device. 2. The optical pickup device according to claim 1, wherein a concave space is formed by forming a convex wall portion integrally with the metal block at an outer peripheral portion on one end surface side instead of the spacer member. An optical pickup device comprising: a light source holding member having the same. 3. The composite device has at least two or more light receiving elements provided inside a substrate formed of a transparent resin, and a light receiving surface of a light receiving element in a central region between the two or more light receiving elements. Having a structure provided with diffraction means on the resin surface on the side,
Further, the connection between the terminal of the light receiving element built in the composite element and the external terminal is wired by a conductive pattern, and this wiring pattern is provided in the central region between at least two or more light receiving elements and the light receiving element. 2. The optical pickup device according to claim 1, wherein the wiring is provided in a region avoiding an optical path passing through a diffraction means provided on the surface-side resin surface. 4. The optical pickup device according to claim 1, wherein the surface of the light source holding member is formed as a mirror surface treatment capable of reflecting light, and the inside of the spacer member has a characteristic of absorbing light. 5. A composite device comprising a transparent glass substrate provided with diffracting means, at least two light receiving elements provided on the same surface as the diffracting means, and having the same refractive index as the window material inside the light source. The light-receiving element has a structure in which the light-receiving side of the light-receiving element is adhered to the glass substrate surface at the same thickness as the window material, and the reflective member is provided with a reflective coating on one end side of transparent glass. 3. The optical pickup device according to claim 2, wherein a surface provided with a reflective coating is provided on an optical path of the opening so as to face the light receiving element side. 6. A composite device comprising a metal substrate having an opening in a central region, a diffraction means provided on one end surface side of the opening,
At least two or more light-receiving elements have a structure in which the light-receiving surface of the light-receiving element is directed outward in the peripheral region of the opening on the other end surface side, and the reflection member further has a reflective coating on one end surface side of transparent glass 3. The optical pickup device according to claim 2, wherein the optical pickup device has a structure in which the reflection-coated surface is adhered to the light source holding member on the optical path of the opening of the light source holding member. 7. The light source holding member in contact with the reflecting member has a surface,
3. The optical pickup device according to claim 2, wherein the optical pickup device has a characteristic of absorbing light. 8. Each element is configured such that an optical path length of the signal light separated by the signal light separating element to the light receiving element is equal to an optical path length between the signal light separating element and the light source. The optical pickup device according to claim 1, wherein the optical member has a structure in which a refractive index and a thickness of the optical member are adjusted.