JP4258911B2 - Optical pickup device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical pickup used in an optical disc apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, optical disk devices have been widely used in computer peripheral devices, optical communication devices, and the like, which are devices to which semiconductor lasers are applied. Further, a semiconductor laser diode (LD) is used as a laser light source for writing and reading a signal to and from a recording medium. An optical element for collecting, separating and detecting laser light, a detector, and an LD are called an optical pickup.
[0003]
In recent years, development of an apparatus that can mount an optical disk device in a personal computer (PC) and handle a large-capacity recording medium has been advanced. Further, considering the mounting on a notebook PC, the optical disc apparatus is required to be reduced in size and power consumption. On the other hand, in order to effectively use the space in the optical disc apparatus, it is necessary to reduce the weight and size of the optical components used.
[0004]
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 disc apparatus. This is a configuration in which the signal light for detecting the tracking signal and the focusing signal is separated by a hologram, thereby integrating the functions. In the figure, the laser light emitted from the semiconductor laser diode 1 (LD) is transmitted through the hologram 21 while spreading at a certain angle, and is corrected to parallel light by the collimating lens 3 (CL). Further, the light passes through the polarizing beam splitter 4 (PBS), passes through the objective lens 5, and is condensed on the surface of the recording medium 6. The reflected light reflected from the surface of the recording medium 6 is divided into two by the polarization beam splitter 4 (PBS) through the objective lens 5, and further diffracted and separated by the polarization separation element 7 (Wollaston prism). The light passes through the condenser lens 8 and is detected as an optical signal by the first light receiving element 9.
[0005]
On the other hand, the reflected light transmitted through the polarizing beam splitter 4 (PBS) reaches the hologram 21 through the collimating lens 3 (CL). Here, a part of the laser light is diffracted and collected on the light receiving element 23 (PD) divided into four regions, ie, two regions that diffract the tracking signal component and two regions that diffract the focusing signal component. A tracking signal and a focusing signal are detected.
On the other hand, the detection mechanism portion composed of the hologram 21, the semiconductor laser diode 1 (LD), the reflecting prism 24b, and the light receiving element 23 (PD) has a structure in which these elements are arranged on the same surface of the base portion 40. have. Thereby, 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 reflecting prism 24 b and incident on the hologram 21. Further, the hologram 21 transmits the light source 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).
[0006]
As described above, the semiconductor laser diode 1 (LD) and the reflecting prism 24b, the light receiving element 23 (PD) and the hologram 21 provided on the same surface of the base portion 40 are packaged, and the parts are integrated and miniaturized. Is realized.
[0007]
[Problems to be solved by the invention]
However, in the above optical system, the silicon crystal, which is the material of the light receiving element (PD), has a lower thermal conductivity than the metal, so that the heat generated by the semiconductor laser diode 1 (LD) chip can be radiated efficiently. It was difficult. In addition, an insulating plate is required because it is necessary to electrically insulate the back surface of the light receiving element (PD), which further hinders heat dissipation. In addition, failures that occur during assembly / mounting may include destruction of the semiconductor laser diode 1 (LD) chip, disconnection of the light receiving element (PD) wiring, and capping defects. Since it is confirmed by a test after completion, if an inferior product comes out, the entire integrated part is discarded. This makes it difficult to reuse the parts, and it is difficult to improve the yield.
[0008]
Therefore, an object of the present invention is to provide a low-cost optical pickup that has a small and integrated optical signal detection mechanism, high signal quality, and high yield.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following means.
[0010]
FIG. 1 shows a basic configuration diagram of the present invention.
[0011]
Basically, a light source (laser light) that irradiates light onto the recording surface of the optical recording medium, correction means (CL) that serves to convert the spread laser light into parallel light, and the parallel light on the recording medium The optical system is composed of condensing means (objective lens) for condensing light. 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 unit is provided between the condensing unit (objective lens) and the correcting unit (CL). And a polarization separation element (Wollaston prism: WP) as a first separation means, and a first light receiving portion (PD1). In order to detect a servo signal composed of a tracking signal and a focusing signal, a diffraction means (hologram) integrated with the second light receiving part (PD2) is provided between the correction means (CL) and the light source (LD). Is used.
[0012]
That is, an optical pickup device according to the present invention is a recording surface of an optical recording medium in an optical pickup device that performs at least one of reading a magneto-optical signal recorded on the optical recording medium and writing on the optical recording medium. A light source for irradiating light, a light receiving means for receiving light reflected on the recording surface of the optical recording medium, detecting a tracking signal and a servo signal of a focusing signal, and transmitting light from the light source to perform optical recording A detection mechanism unit having a diffractive unit that diffracts the light reflected by the medium and enters the light reception unit, and the detection mechanism unit is a composite element configured with the light reception unit and the diffraction unit as an integrated structure; An opening penetrating the center of the metal block having both end faces is provided, and a reflection surface having a mirror-finished surface is provided in the peripheral area of the opening on one end face, and light is emitted from the opening on the other end face. A light source holding member that is press-fitted and installed, and a spacer member in which the composite element and the light source holding member are installed in parallel to face each other at a predetermined interval, and a space for blocking external light is provided therein. Configured (corresponding to claim 1). 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 them. Therefore, there is an effect that the possibility of generating a defective product is lower than that in the case of manufacturing integrally. Further, by separating the light emitting element and the light receiving element electrically and thermally, a stable signal can be obtained and high reliability can be obtained.
[0013]
Alternatively, the light source holding member may be integrally formed with a shape corresponding to the spacer member, and the spacer member of the detection mechanism portion according to claim 1 may be omitted (corresponding to claim 2). By adopting this configuration, a light emitting element and a light receiving element can be manufactured separately, and by combining them, a high yield can be obtained, and there is a possibility that defective products may be generated compared to a case where they are manufactured integrally. In addition to the effects of claim 1, in addition to the effect of claim 1, and the point that the light emitting element and the light receiving element are electrically and thermally separated, a stable signal can be obtained and high reliability can be obtained. The number of parts can be reduced, and the cost can be reduced.
[0014]
Next, as a first form of the composite element, at least two or more light receiving elements are provided inside a substrate formed of a resin having transparency, and a light is received in a central region between the two or more light receiving elements. The element is configured to have a structure in which diffraction means is provided on the resin surface on the light receiving surface side of the element (corresponding to claim 3). By doing so, the second light receiving section (PD2) and the diffracting means (hologram) can be made into an integrated structure, and cost reduction and optical adjustment are facilitated. That is, the Si chip is arranged with high accuracy on the material constituting the wiring, and after wiring the Si chip terminal and the wiring, the second light receiving part (PD2) is manufactured by encapsulating with optical resin. . Further, since the diffractive means (hologram) is produced on the surface at the same time as encapsulating the resin, man-hours and materials can be reduced, and the element can be accurately produced.
[0015]
As a second form of the composite element, a diffractive means is provided on the surface of a transparent glass substrate, at least two light receiving elements are provided on the same side as the diffractive means, and the refractive index is the same as that of the window material inside the light source. An effect of facilitating the production by having a structure in which the light receiving surface side of the light receiving element is bonded to the glass substrate surface with the same thickness as the window material and having the same thickness as the window material (corresponding to claim 5) There is. Further, the reflecting member has a structure in which a reflective coating is provided on one end surface side of the transparent glass, and the reflective coating is provided on the optical path of the opening of the light source holding member so as to face the light receiving element side. With this configuration (corresponding to claim 5), there is no wiring such as wiring, tact time can be reduced, and an effect contributing to cost reduction is produced.
[0016]
Furthermore, as a third form of the composite element, the composite element is configured by a metal substrate having an opening in the central region, a diffractive means is provided on one end face side of the opening, and at least two light receiving elements are provided on the other end face side. A structure in which the light receiving surface of the light receiving element is attached to the outside in the peripheral region of the opening is configured (corresponding to claim 6). In addition, the reflecting member has a structure in which a reflective coating is applied to one end surface side of transparent glass, and is attached on the optical path of the opening of the light source holding member so that the surface on which the reflective coating is applied is adhered to the light source holding member. It comprises so that it may have (corresponding to claim 6). By doing so, the optical path can be made equal, and the aberration at the focused spot on the light receiving element can be reduced. In addition, it is possible to reduce the influence of chromatic aberration of the optical material. As a result, the quality of the obtained signal is improved.
[0017]
Moreover, the following three measures are implemented as countermeasures for stray light.
[0018]
That is, the connection between the terminal of the light receiving element incorporated in the composite element and the external terminal is wired with a conductive pattern, and this wiring pattern is provided in the central region between at least two light receiving elements and the light receiving element. 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.
[0019]
In addition, the surface of the light source holding member is formed as a mirror finish capable of reflecting light, and the inside of the spacer member is configured to absorb light (corresponding to claim 4). By doing this, 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 in contact with the reflecting member is configured to have a property of absorbing light (corresponding to claim 7). Further, in order to avoid that the light source light emitted from the light source directly enters the second light receiving unit (PD2), it is an effective means to form an aperture in the reflecting member. By doing so, stray light can be reduced, and signal quality is improved.
[0020]
Next, in the optical system shown in FIG. 1, the servo signal light is diffracted by the diffracting means (hologram), reflected once by the reflecting member, and then passed through the base material of the diffracting means (hologram) to receive the second light receiving portion ( Focus on PD2). Usually, in a quasi-confocal optical system using a diffracting means (hologram), the focal position of the diffracted light is set to the same position as the focal position of the light source. Therefore, by providing an optically symmetrical arrangement with the reflective surface as the center, a pseudo confocal optical system equivalent to the case without the reflective surface is formed. In this case, the refractive index and thickness of the member through which the signal light is transmitted after reflection are substantially the same as those of the member through which the light source laser beam is transmitted in the forward path.
[0021]
In other words, in the present invention, each element is set so that the optical path length until the signal light separated by the signal light separating element reaches the light receiving element is equal to the optical path length to the signal light separating element and the light source. The optical member is configured to have a structure in which the refractive index and thickness are adjusted (corresponding to claim 8). By doing so, it is possible to minimize the convergence generated at the condensing position of the signal light and to equalize the optical optical path, and to prevent deterioration of the quality of the servo signal.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
In order to more specifically show the effects of the present invention, examples thereof are given below.
Example (1)
FIG. 2 shows an optical pickup device of the present invention as a first embodiment.
[0023]
In this embodiment, the semiconductor laser diode 1 (LD), the reflecting member 24, the composite element 2, the collimating lens 3 (CL), the polarizing beam splitter 4 (PBS), the Wollaston prism 7 (WP), and the first light receiving element 9 are used. The optical pickup having the objective lens 5 is configured. The semiconductor laser diode 1 (LD) has a center oscillation wavelength of 685 nm and a spread angle of about 20 degrees, and is a CAN type. By using the CAN type, it is possible to realize cost reduction due to the mass production effect.
[0024]
Further, the CAN type semiconductor laser diode 1 (LD) is fixed by press-fitting aluminum having good heat conduction into the LD holding member 11. In this way, the problem of heat dissipation can be solved.
[0025]
Thus, the material of the LD holding member 11 is preferably aluminum in consideration of thermal conductivity and cost. An outer shape is produced by casting, and a portion where the semiconductor laser diode 1 (LD) is press-fitted and a portion where the reflecting member 24 is fixed are cut.
[0026]
FIG. 4 shows the structure of the reflecting member 24 and the patterning shape of the reflecting surface. Regarding the reflecting member 24, if a mirror surface portion is produced on the surface of the LD holding member 11, and the reflecting member 24 is integrated to form the reflecting surface 25, the number of parts 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 on the base of the reflective layer. An Au film is produced as a reflective film by sputtering, and an MgF film is provided on the surface for protection. Also, black paint is convenient for stray light countermeasures.
[0027]
As another example, the reflecting member 24 can be manufactured by patterning a reflecting film on the surface of a transparent substrate. The material is a glass substrate (BK7). However, a circular opening pattern (aperture) is provided in the central portion in order to transmit the light source light in the forward path, and AR coating is applied to that portion. A dielectric multilayer film is used as the material of the reflective film. In addition, an Au film can be used as the metal film. In order to prevent excessive diffused light from the LD, the opening pattern is preferably formed on the back surface of the reflecting 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.
[0028]
As another example, the reflecting member 24 can be made of a material that does not transmit light. In this case, the transmitted light from the light source can be emitted through a hole provided in the reflecting member 24, for example, a circular space, and the signal light from the hologram 21 can be reflected by a mirror-finished surface. A reflective surface is made of a dielectric multilayer film or an Au film on the surface and patterned to prevent stray light from going to the light receiving element.
[0029]
For the portion where the LD holding member 11 and the reflecting member 24 are bonded, an ultraviolet curable adhesive having low viscosity and quick curing is used. 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 scattering. In addition, an adhesive that absorbs light or an adhesive mixed with fine particles may be used.
[0030]
FIG. 3 shows an example of a composite element in which the hologram 21 and the second light receiving element 22 (PD2) are integrated.
[0031]
A thin metal plate is patterned to produce a wiring, and the second light receiving element 22 (PD2) is fixed thereon. The periphery of the second light receiving element 22 (PD2) is embedded with a material transparent to the laser light from the semiconductor laser diode 1 (LD) as a light source, and a hologram 21 is formed on the surface thereof. Yes. A space is provided in the wiring so that transmitted light from the light source can pass therethrough. However, the space is filled with the above transparent substance, and has an optically mirrored surface state. As this transparent substance, for example, an amorphous polyolefin resin (product name: ZONEX) was employed in this example. In constructing the quasi-confocal optical system, since the optical path length from the hologram 21 needs to be equal to the optical path length to the semiconductor laser diode 1 (LD), the refractive index of the resin is the semiconductor laser diode 1 (LD The thickness from the hologram 21 surface to the light receiving surface is also the combined thickness of the reflecting member 24 and the window material. Even when materials having different refractive indexes are used, there is no problem with respect to reception of signal light as long as the optical path lengths are equal.
[0032]
As a method for producing the composite element 2, a molding method using plastic as a material is employed. By transferring the pattern shape of the hologram 21 to the mold, it is possible to manufacture a composite element with a high yield while ensuring positional accuracy with the second light receiving element 22 (PD2).
[0033]
When the reflecting member 24 is formed of an optical flat substrate, the surface in contact with the LD holding member 11 is subjected to surface treatment for the purpose of absorbing the light scattered inside. Alternatively, when the reflecting member 24 is bonded to the LD holding member 11, the adhesive may have a property of absorbing light.
[0034]
Further, the surface of the LD holding member 11 is mirror-finished and patterned so as to reflect only the diffracted light from the hologram 21, and a light-absorbing surface treatment is applied to the other part to form a reflecting surface 25. You can also In this case, an aperture is formed on the back side of the semiconductor laser diode 1 (LD) in order to limit the excessive spread light from the semiconductor laser diode 1 (LD). The semiconductor laser diode 1 (LD) employs a CAN package, and is fixed by being pressed into the LD holding member 11. The LD holding member 11 uses an aluminum plate as a metal material.
[0035]
FIG. 5 shows a manufacturing process of the composite element 2.
[0036]
The composite element 2 has a structure in which a metal thin plate is patterned to form a wiring portion, and a Si chip as a light receiving element is soldered to the surface. After wiring each terminal on the Si chip and the wiring portion, a resin is poured and a hologram of the outer shape and the surface is produced by a molding method. The wiring portion has a space for transmitting the laser light from the semiconductor laser diode 1 (LD) and the signal light from the recording medium 6. Usually, since resin enters the mold during molding, the manufacturing process is performed by backing a mirror ceramic substrate on the back surface of a thin metal plate. Thereby, when peeling from a board | substrate, an optical plane can be maintained. Finally, after AR coating is applied to both sides, it is cut out by dicing. Through the above steps, the composite element 2 can be mass-produced efficiently.
[0037]
The hologram 21 has a pattern divided into four to diffract the tracking signal and the focusing signal. In the forward path, the laser beam is transmitted with a zero-order diffraction efficiency of 80%, and in the return path, the signal light is diffracted with a first-order diffraction efficiency of 9% and guided onto the PD. AR coating is applied to the front and back surfaces to provide a coating with little loss against incident light from an oblique direction. Considering that the collimating lens 3 (CL) and the objective lens 5 are lightweight, plastic lenses are used. Other glass materials can also be used. Further, in the polarization beam splitter 4 (PBS), the transmittance of the P-polarized light that is the same as that of the semiconductor laser diode 1 (LD) of the light source is 85%, and the reflectance of the S-polarized light that is the same as the magneto-optical signal is used. 97% or more.
[0038]
With respect to the polarization separating element 7 (Wollaston prism: 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. I have it. A polarization separating element 7 (Wollaston prism: WP) is configured by bonding two prisms whose crystal axis directions are perpendicular to each other. A condensing lens 8 is added to the surface.
[0039]
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.
Example (2)
A detailed structure of the composite element 2 in which the wiring process on the second light receiving portion (PD2) is simplified is shown in FIG.
[0040]
The composite element 2 in the present 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, the hologram 21 is produced on a glass substrate, and a wiring pattern is also added on the surface thereof. The light receiving surface of the Si chip that is the second light receiving unit 22 (PD2) is arranged to face the diffraction surface of the hologram 21.
[0041]
The hologram 21 uses a glass substrate (BK7) as a heat-resistant optical material, and a surface relief hologram is produced on the surface by RIE (Reactive Ion Etching). Further, after the metal film is sputtered, only a necessary portion is patterned and removed to produce a wiring portion. The Si chip as the second light receiving element 22 is positioned and electrically connected so that the terminal portion of the signal and the wiring portion are in contact with each other. For example, the wiring portion can be pre-soldered, and the Si chip can be positioned and then heated to obtain and fix the electrical connection. Since the wiring is exposed, wiring to an external circuit is easy, and the Si chip wiring process is eliminated. In addition, the LD holding member 11 that is made of metal and is electrically at the same potential as GND is brought into contact with and adhered to a glass substrate that is an insulating material to electrically separate the signal from the PD. Yes.
[0042]
The surface of the LD holding member 11 is mirror-finished, and a reflection film is applied to the reflection part of the signal light, and an absorption film for preventing stray light is applied to the other part, thereby reducing the number of parts and reducing the cost. Become.
[0043]
Further, since the signal light is required to be optically symmetrical on the reflecting surface, the reflecting member and the LD window material substrate have the same material and thickness with respect to the diffraction means (hologram) substrate. . However, in order to fix the Si chip on the diffracting means (hologram), an optical adhesive having a refractive index and thickness substantially the same as those of the LD window material is used. As a result, an optical path corresponding to the window material of the LD can be created, and aberrations generated in the signal light can be reduced. With the above configuration, the wiring process can be simplified.
Example (3)
FIG. 7 shows a detailed structure of a composite element 2 having another shape and advantage of the present invention as a third embodiment.
[0044]
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 positioned on the light source side with respect to the diffraction surface of the hologram 21.
[0045]
The hologram substrate is produced by a replication method (2P method) using an ultraviolet curable resin (photo polymer) or 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.
[0046]
The second light receiving part (PD2) itself is fixed on the substrate with solder or an adhesive. An electrode is provided on the substrate, and wiring is performed from the second light receiving portion (PD2) to the wiring portion. The electrode has a shape penetrating the substrate and is connected to an external terminal. The diffractive means (hologram) is bonded to the back surface of the substrate with respect to the second light receiving portion (PD2). For this purpose, a hole for transmitting light is provided in the substrate of the second light receiving unit (PD2).
[0047]
As shown in FIG. 7, the light receiving element portion is formed on a substrate having a space that allows laser light in the forward path and signal light in the return path to pass therethrough. Since the metal substrate is used, the space portion can be easily processed by press working, can be manufactured at low cost, and has heat resistance against soldering, thereby obtaining an advantageous structure.
[0048]
Since the second light receiving element 22 (PD2) is positioned on the inner side, an insulated terminal is required for connection to an external circuit. At the same time, it is necessary to wire the Si chip and the terminal portion. Insulation with the LD holding member 11 fixes the composite element 2 with an adhesive having no conductivity. Alternatively, a method of insulating the end portion of the composite element 2 may be used. Alternatively, by making the PD substrate a machinable ceramic substrate, insulation from the electrode and the semiconductor laser diode 1 (LD) can be obtained.
[0049]
The reflecting member 24 is made of the same material as the window material of the light source (LD) in terms of the material and thickness of the member, provided that the optical path length is the same. However, the reflecting surface is disposed on the semiconductor laser diode 1 (LD) side. In other words, when viewed from the signal light, the reflection member 24 is once transmitted and reflected at the back surface. At the same time, the aperture portion is configured as a reflective pattern 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.
[0050]
The signal light needs to pass through the reflecting member 24 because of optical aberration. Therefore, a configuration in which a reflecting surface is produced on the surface of the LD holding member 11 and the signal light simply passes through the reflecting member 24 is also possible. In this case, the reflecting member 24 is subjected to AR coating on both the front and back sides. In addition, the opening restriction is performed at the opening provided in the LD holding member 11. Therefore, there is no need for positioning, and the structure becomes easy.
[0051]
With the above structure, the light source (LD) and the signal detection portion can be further downsized.
[0052]
【The invention's effect】
As described above, according to the present invention, the composite element 2 in which the second light receiving element 22 (PD2) and the hologram 21 are integrated, the reflecting member 24, the LD holding member 11, and the semiconductor laser diode 1 (LD) ), The light source and the servo signal can be easily detected, and the pickup optical system is simplified.
[0053]
As a result, heat radiation of the semiconductor laser diode 1 (LD) can be facilitated to enable a stable writing operation, and stray light components mixed in the servo signal can be reduced, so that the servo signal quality can be improved and stable control can be performed. Further, by producing the composite element 2, the optical axis can be easily adjusted and the tact time can be reduced. In addition, since the optical system can be simplified, an inexpensive optical pickup can be provided.
[Brief description of the drawings]
FIG. 1 is a basic configuration diagram of the present invention.
FIG. 2 shows an optical pickup according to the present invention (Example 1).
FIG. 3 shows a composite element structure of the present invention (Example 1).
FIG. 4 Reflector structure and reflective surface patterning shape
FIG. 5 shows a composite element manufacturing process.
FIG. 6 shows a composite element structure of the present invention (Example 2).
FIG. 7 shows a composite element structure of 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: Polarizing 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: Reflective member
24b: Reflecting prism
25: Reflective surface
26: Light absorption film
30: Electrode
31: Metal film
32: Mirror surface ceramic substrate
33: Resin
34: Mold
40: Base part

Claims (8)

In an optical pickup device that performs at least one of reading a magneto-optical signal recorded on an optical recording medium and writing on the optical recording medium,
A light source for irradiating light onto the recording surface of the optical recording medium;
Light receiving means for receiving light reflected on the recording surface of the optical recording medium and detecting servo signals of tracking signals and focusing signals;
A detection mechanism unit having a diffractive means that transmits light from a light source, diffracts light reflected by the optical recording medium, and enters the light receiving means; and a unit structure;
Have
The detection mechanism is provided with a composite element in which the light receiving means and the diffraction means are integrated, and an opening that penetrates the center of the metal block having both end faces. A light source holding member that is provided with a reflection surface and press-fitted and installed a light source from an opening on the other end surface;
An optical pickup device comprising a composite element and a light source holding member facing each other at a predetermined interval in parallel, and a spacer member provided with a space for blocking external light inside . The light pickup device according to claim 1, wherein, instead of the spacer member, a light source holding member having a structure in which a concave space is formed by integrally forming a convex wall portion with a metal block on an outer peripheral portion on one end surface side. An optical pickup device characterized by that. The composite element is provided with at least two or more light receiving elements inside a substrate formed of a transparent resin, and is provided on the resin surface in the central region between the two or more light receiving elements and on the light receiving surface side of the light receiving element. The structure has a diffractive means, and the connection between the terminal of the light receiving element built in the composite element and the external terminal is wired with a conductive pattern, and this wiring pattern is provided between at least two light receiving elements. 2. The optical pickup device according to claim 1, wherein wiring is performed in a region avoiding the optical path passing through the diffraction means provided in the resin region on the light receiving surface side of the light receiving element in the central region. 2. The optical pickup device according to claim 1, wherein the surface of the light source holding member is formed as a mirror treatment capable of reflecting light, and the inside of the spacer member has a characteristic of absorbing light. The composite element is provided with a diffractive means on the surface of a transparent glass substrate, at least two or more light receiving elements are provided on the same surface side as the diffractive means, and an optical adhesive having the same refractive index as the window material inside the light source, and a window The light receiving surface side of the light receiving element is bonded to the glass substrate surface with the same thickness as the material, and the reflective member is provided with a reflective coating on one end surface side of the transparent glass, on the optical path of the opening of the light source holding member 3. The optical pickup device according to claim 2, wherein a surface provided with a reflective coating is provided facing the light receiving element side. The composite element is composed of a metal substrate having an opening in the central region, diffractive means is provided on one end surface side of the opening, and at least two light receiving elements are provided in the peripheral region of the opening on the other end surface side. The reflective member is provided with a reflective coating on one end surface side of the transparent glass, on the optical path of the opening of the light source holding member, and with the reflective coating. The optical pickup device according to claim 2, wherein the optical pickup device has a structure in which is attached to a light source holding member. 3. The optical pickup device according to claim 2, wherein the surface of the light source holding member in contact with the reflecting member has a characteristic of absorbing light. Refraction of optical members constituting each element so that the optical path length until the signal light separated by the signal light separation element reaches the light receiving element is equal to the optical path length to the signal light separation element and the light source. 3. The optical pickup device according to claim 1, wherein the optical pickup device has a structure in which the rate and thickness are adjusted.

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