JP2002197705A - Optical head device and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the constitution of an optical head device in which deficiencies such as positional deviation and posture inclination of optical parts mounted on a frame made of resin do not occur even if temperature change occurs for the frame. SOLUTION: In the frame 3 made of resin used for the optical head device 1, local expansion, shrinkage or the like do not occur even when temperature change occurs for the frame 3, since any of the thickness of the frame sidewall 331 of a prism mounting part and a cylindrical projecting part 370 to which a holder supporting member is adhered and fixed is made uniform by holes 51 and 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical head device used for recording and reproducing an optical recording medium such as a CD (compact disk) and a DVD (digital versatile disk). More specifically, the present invention relates to a structure of a frame on which optical components are mounted in an optical head device.

[0002]

2. Description of the Related Art In an optical head device used for recording and reproducing data on and from an optical recording medium such as a CD or a DVD, light emitted from a light source is guided to an objective lens via a light guide system, and the light converged by the objective lens. Is converged on the optical recording medium. At this time, the objective lens is driven in the tracking direction and the focusing direction by a lens driving device.
The return light from the optical recording medium is also guided to a light receiving element via a light guide system. here,
Various optical components constituting the light guide system are mounted at predetermined positions on a frame together with a light source and a light receiving element.

Conventionally, a metal frame has been used, but a resin frame is being used for the purpose of reducing the weight and cost of the optical head device. The resin frame has a plurality of optical component mounting portions on which a plurality of optical components are mounted, respectively. Of these optical component mounting portions, the prism mounting portion 330 shown in FIG. The side surface of the cubic prism 22 (optical component) contacts the inner surface of the side wall 331 and is positioned.

Here, the back side 335 of the frame side wall 331
As shown in FIG. 8, when the frame side wall 331 is viewed obliquely from the rear side, the frame side wall 331 is concavely formed in an arc shape in accordance with the shape of the support arranged on the disk drive device side.

Further, near the prism mounting section 330,
As shown in FIG. 4, a cylindrical holder support member 35 that supports the objective lens movably in a tracking direction and a focusing direction via a lens holder is disposed.
For this reason, the columnar convex portion 370 protrudes upward from the frame side wall 331, and this columnar convex portion 370 divides the holder supporting member mounting portion 350 on which the holder supporting member 35 is arranged, together with other convex portions, into a circular shape. Used to form. Further, in a state where the lower half of the holder support member 35 is stored in the holder support member mounting portion 350, an adhesive is applied between the side surface of the holder support member 35 and the columnar convex portion 370.

As described above, in the prism mounting section 330,
As shown in FIG. 9A, a cross section of the frame side wall 331 is in contact with the side surface of the prism 22.
Is formed as a flat surface while its back side 335 is formed.
Since (outside) is concave in an arc shape, the frame side wall 331 with which the prism 22 abuts is formed thick as a whole, and the thickness varies considerably depending on the location. Further, the columnar convex portion 370 is provided in the holder supporting member mounting portion 3.
Since it is used to form a circular section 50 and is used to adhesively fix the holder support member 35,
As shown in FIG. 9B, the cross section of the columnar projection 370 is formed to be thick as a whole, and the thickness varies considerably depending on the location.

[0007]

In the resin frame 3 configured as described above, when a temperature change is applied, the resin expands and contracts more in a thick portion than in other portions. Mounting part 3 with thick wall
In the case of 30, there is a problem that deformation such as a decrease in verticality occurs on the frame side wall 331 with which the prism 22 abuts due to a temperature change, and the prism 22 is inclined.

If a thick columnar projection 370 is also formed above the frame side wall 331, the expansion and contraction of the columnar projection 370 affects the frame side wall 331 with which the prism 22 abuts. Of the verticality of the
Become noticeable.

[0009] In view of the above problems, an object of the present invention is to provide:
To provide a configuration in an optical head device in which even if a temperature change is applied to a resin frame on which an optical component is mounted, the optical component mounted on the frame does not cause a problem such as a displacement or an inclination of a posture. It is in.

[0010]

In order to solve the above-mentioned problems, the present invention provides a light source, a lens driving device for driving an objective lens for converging light emitted from the light source to an optical recording medium, and an optical recording medium. A light-receiving element for receiving the return light, a plurality of optical components for guiding the light emitted from the light source to the objective lens, and a return light from the optical recording medium to the light-receiving element, and the plurality of optical components. In the optical head device having a frame on which the light source, the lens driving device, and the light receiving element are mounted, a plurality of optical component mounting portions of the frame on which the plurality of optical components are mounted, respectively, A hole is formed in the back side of the frame side wall with which the mounted optical component is in contact, so that at least one optical component mounting portion having a uniform thickness of the frame side wall is included. It is characterized in that is.

When a temperature change is applied to the resin frame of the optical head device, the resin expands and contracts sharply in a thick portion compared to other portions, and stress is concentrated, and the shape of the optical component mounting portion is changed. Although it is apt to change, in the present invention, a hole is formed on the back surface side of the frame side wall with which the optical component contacts, so that the thickness of the frame side wall is made uniform. Therefore, even when there is a temperature change in the resin frame, local expansion and contraction do not occur on the frame side wall, so that the optical component is always mounted on the frame with high mounting accuracy. Therefore, the optical head device has stable characteristics. Further, the holes also have an effect of preventing sink when molding the resin frame.

In the present invention, the optical component mounting portion in which the thickness is made uniform is, for example, a prism mounting portion in which a side surface of a prism abuts on the side wall of the frame.

According to the present invention, in the optical component mounting portion in which the thickness is made uniform, when the columnar convex portion extends upward from the frame side wall with which the optical component is in contact, the hole is formed by the hole. It is preferable that the thickness is continuously formed from the back side of the frame side wall to the back side of the columnar protrusion so that the thickness of the frame side wall and the thickness of the columnar protrusion are made uniform. With this configuration, even when a temperature change is applied to the resin frame, local expansion, contraction, and the like do not occur in the columnar protrusions. Therefore, the optical head device has stable characteristics because there is no deformation such as a decrease in the verticality of the frame side wall under the influence of the expansion and contraction of the columnar convex portion.

In the present invention, for example, the column-shaped projection is provided with a holder supporting member for supporting the objective lens movably in both a tracking direction and a focusing direction via a lens holder in the lens driving device. In a case where the holder support member mounting section is formed by partitioning, the holder support member disposed on the holder support member mounting section is fixed to the columnar convex portion by an adhesive. With this configuration, even when a temperature change is applied to the resin frame, no deformation or the like occurs in the columnar convex portion to which the holder support member is adhered and fixed, so that the objective lens is always supported in a suitable state. The optical head device has stable characteristics.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical head device to which the present invention is applied will be described below with reference to the drawings.

(Overall Configuration) FIG. 1 is a plan view of a main part of an optical head device for recording and reproducing a CD, a CD-R, and a DVD. 2A, 2B, 2C, and 2D are a plan view, a left side view, a right side view, and a bottom view of the optical head device shown in FIG. 1, respectively. 3 (A), (B),
2C and 2D are a plan view, a left side view, a right side view, and a bottom view of the resin frame used for the optical head device shown in FIG. 1, respectively.

As shown in FIGS. 1, 2 and 3, the optical head device 1 has a resin frame 3. The resin frame 3 has two guide shafts 2A and 2B attached to the device so as to be parallel to each other.
01, 302, and 303 can move along the guide shafts 2A and 2B. An optical system described below is formed on the resin frame 3.

The optical system of the optical head device 1 includes a DVD laser diode 4 for emitting a first laser beam L1 and a CD laser diode 5 for emitting a second laser beam L2. Guiding the first and second laser beams L1 and L2 emitted from the diodes 4 and 5 to a common optical path 6, and using this common optical path 6 to perform all recording / reproduction of a CD, a CD-R, and a DVD Is available.

The common light path 6 includes a light receiving element 11, a sensor lens 10, a light guide system 20, a light receiving element 11 mounted on the resin frame 3.
It is defined by a collimating lens 7, a rising mirror 8, and an objective lens 9 arranged above the rising mirror 8.

The DVD laser diode 4 is for recording and reproducing DVDs, and emits a first laser beam L1 having a wavelength of 650 nm or 635 nm. On the other hand, the CD laser diode 5 is for recording and reproducing CDs and CD-Rs, and emits a second laser beam L2 having a wavelength of 780 to 800 nm. The laser diodes 4 and 5 are arranged on the same side of the light guide system 20 of the common optical path 6 so that their optical axes L10 and L20
Are arranged in parallel. In the example shown here, the DVD laser diode 4 is arranged closer to the light receiving element 11 than the CD laser diode 5.

The first laser light L 1 emitted from the DVD laser diode 4 directly enters the light guide system 20.
On the other hand, the second laser light L2 emitted from the CD laser diode 5 enters the light guide system 20 via the diffraction grating 12. The diffraction grating 12 is given predetermined diffraction characteristics, and divides the second laser light L2 emitted from the CD laser diode 5 into three beams.

The circuit board 410 on which the DVD laser diode 4 is mounted is fixed to the side surface 317 of the resin frame 3 with an adhesive, and the circuit board 410 has a shield case 60 attached thereto. Is covered. Thereby, the DVD laser diode 4 is arranged at the entrance of the hole 305 formed in the resin frame 3, and emits the first laser light L <b> 1 to the light guide system 20 through the hole 305. Further, the heat sink 40 to which the laser diode 5 for CD is fixed is adhered and fixed to the side surface 316 of the resin frame 3. Thereby, C
The laser diode 5 for D is disposed at the entrance of a hole 306 formed in the resin frame 3,
6, the second laser light L2 is emitted to the light guide system 20 via the diffraction grating 12.

The light guide system 20 is composed of a half mirror 21 having a partially reflecting surface and a prism 22 having a partially reflecting surface. The half mirror 21 has a partially reflected surface of the first laser beam L emitted from the laser diode 4.
They are arranged so as to be inclined 45 degrees with respect to one optical axis L10. The prism 22 has a second laser beam L2 whose partial reflection surface is emitted from the laser diode 5.
Are arranged so as to be inclined 45 degrees with respect to the optical axis L20.

The thus configured optical head device 1 of the present embodiment.
In the first, the first DVD
Of the laser light L1 is reflected by the partially reflecting surface of the half mirror 21, and the reflected light is incident on the partially reflecting surface of the prism 22 with its optical axis bent by 90 degrees. Then, the laser light L incident on the partial reflection surface
Most of the light 1 is transmitted directly to the rising mirror 8. On the other hand, the second laser light L2 for CD incident on the prism 22 is reflected by the partially reflecting surface of the prism 22 so that almost half of the light component is reflected, the optical axis thereof is bent by 90 degrees, and is incident on the rising mirror 8. . As described above, the first and second laser beams L1 and L2 are both guided to the common optical path 6 by the light guide system 20 including the half mirror 21 and the prism 22.

The DVD laser light L 1 and the CD laser light L 2 guided to the common optical path 6 by the light guide system 20.
Is reflected at right angles by the rising mirror 8 and then converted by the collimating lens 7 into a parallel light beam. The laser beams L1 and L2 converted into parallel light beams are guided to an objective lens 9, and the laser beam L1 for DVD is condensed as a light spot on a recording surface of a DVD as an optical recording medium via the objective lens 9. . The laser light L2 for CD is focused as a light spot on the recording surface of a CD or CD-R as an optical recording medium.

Laser light L1, L2 reflected by the optical recording medium
Return light returns through the objective lens 9, the collimating lens 7, and the rising mirror 8, and returns to the light guide system 20 again. Of these return lights, most of the return light of the DVD laser light L1 passes through the partial reflection surface of the prism 22 as it is and returns to the half mirror 21. And half mirror 2
One half of the light passes through one partial reflection surface and enters the sensor lens 10. On the other hand, the return light of the laser light L2 for CD passes through the partially reflecting surface of the prism 22, and half of the light returns to the half mirror 21. Then, the light passes through the partially reflecting surface of the half mirror 21 as it is, and
Incident on. After that, each return light is focused on the common light receiving element 11 through the sensor lens 10. Sensor lens 1
Reference numeral 0 denotes a lens for generating astigmatism with respect to the return light of both laser beams L1 and L2.

In this embodiment, the sensor lens 10 is
It is arranged at the exit of a hole 307 formed in the resin frame 3 and detects light transmitted through the half mirror 21 through the hole 307. In addition, the sensor lens 10
Behind the circuit board 1 on which the light receiving element 11 is mounted
Numeral 10 is bonded and fixed to the side surface 311 of the resin frame 3, whereby the light receiving element 11 is mounted on the resin frame 3.

In the optical head device 1 configured as described above, the objective lens driving device 70 for driving the objective lens 9 in the focusing direction and the tracking direction has a lens holder 71 holding the objective lens 9. The lens holder 71 includes a cylindrical body 72 and a body 7.
2 is provided with a cylindrical bearing portion 73 formed inside. A pair of tracking drive coils 81 and a pair of focusing drive coils 82 are formed on the outer peripheral surface of the body 72.

A support shaft 91 stands upright from the bottom wall of the holder support member 35 held by the resin frame 3, and the support shaft 91 is inserted into the bearing 73 of the lens holder 71. The holder support member 35 has an outer wall 356.
An inner wall 357 is formed, and a pair of tracking drive magnets 83 is attached to the outer wall 356 so as to face the tracking drive coil 81 and constitute a tracking magnetic circuit. Therefore, the lens holder 71 can be rotated around the support shaft 91 to perform tracking error correction.

Further, a pair of focusing drive magnets 84 constituting a focusing magnetic circuit are attached to the outer wall 356 so as to face the focusing drive coil 82. Therefore, the lens holder 71 is connected to the support shaft 91
To correct the focusing error.

The lens holder 71 is connected to a flexible substrate 77 whose intermediate position is supported by the cut-and-raised portion 359 of the holder support member 35. Further, a cover 355 is covered on the upper surface of the holder support member 35 (see FIG. 2A).

(Characteristic Structure of Resin Frame) FIG.
FIG. 3 shows the prism mounting portion formed on the resin frame.
It is the perspective view seen from the direction of arrow X of (A). FIG.
4A and 4B are a perspective view and a side view, respectively, of the prism mounting portion shown in FIG. 4 as viewed from the back side (the direction indicated by the arrow Y in FIG. 3A). FIGS. 6A and 6B are diagrams of FIG.
FIG. 5 (B) is a cross-sectional view showing a state where the frame side wall of the prism mounting portion is cut at a position corresponding to the line AA ′ in FIG. 5 (B), and FIG.
FIG. 6 is a cross-sectional view showing a state of cutting at a position corresponding to line BB ′ of FIG.

In the optical head device 1 of the present embodiment, the resin frame 3 has a plurality of optical component mounting portions on which a plurality of optical components such as the prism 22 and the half mirror 21 are mounted. Among these optical component mounting portions, the prism mounting portion is positioned so that the side surface of the cubic prism 22 (optical component) abuts against the inner surface of the frame side wall 331 as shown in FIG. Has become. Here, the back side 335 of the frame side wall 331 in contact with the prism 22 is concave in an arc shape in accordance with the shape of the support arranged on the side of the disk drive.

In the vicinity of the prism mounting section 330,
A cylindrical holder support member 35 that movably supports the objective lens 9 in the tracking direction and the focusing direction via the lens holder 71 is disposed. For this reason, from the frame side wall 331, the columnar convex portion 370 is directed upward.
The column-shaped convex portion 370 forms, together with the other convex portions, a holder supporting member mounting portion 350 on which the holder supporting member 35 is arranged, in a circular shape. Here, the lower half portion of the holder support member 35 is housed in the holder support member mounting portion 350, and an adhesive is applied between the side surface of the holder support member 35 and the columnar convex portion 370.

In the resin frame 3 configured as described above, the prism mounting portion 330 corresponds to FIGS.
As shown in (A), the inner surface of the frame side wall 331 with which the side surface of the prism 22 abuts is formed as a flat surface, while the back side 335 (outside) is concave in an arc shape, so that the prism 22 abuts. The frame side wall 331 is formed to be thick as a whole, and the thickness varies considerably from place to place.

As shown in FIGS. 5 (B) and 6 (B), the columnar convex portion 370 is provided on the holder supporting member mounting portion 35.
0 is used to define a circular shape and is used to adhere and fix the holder support member 35, so that it is formed thick as a whole, and the thickness varies considerably depending on the location. .

Accordingly, when a temperature change is applied to the resin frame 3, the frame side wall 3 of the thicker portion is compared with the other portions.
The expansion and shrinkage of the resin at the base 31 and the columnar protrusions 370 are severe,
Although the stress tends to be concentrated, in the present embodiment, a hole 51 that opens in a rectangular shape on the back side 335 is formed in the frame side wall 331. Also, a hole 52 that opens in a slit shape is formed on the back surface side of the columnar convex portion 370. Here, hole 5
1, 52 are connected vertically to form one hole 50.

Such a hole 51 is provided in the prism mounting portion 33.
At 0, the thickness of the frame side wall 330 is made uniform because the prism 22 is formed obliquely along the surface where the side surface of the prism 22 abuts. The hole 52 is formed in the columnar convex portion 37.
Since it is formed in a wedge shape along the outer shape of 0, the thickness of the columnar convex portion 370 is also made uniform.

For this reason, in the resin frame 3 used in the optical head device 1 of this embodiment, even when the temperature of the resin frame 3 is changed, the hole 50 is formed in both the frame side wall 331 and the columnar projection 370. (Hole 51, 52)
Because the wall thickness is uniformed, local expansion,
No shrinkage occurs. Therefore, in the resin frame 3, even if there is a temperature change, stress does not concentrate, so that deformation such as a decrease in verticality of the frame side wall 331 with which the prism 22 contacts does not occur. Therefore, the prism 22 is always mounted on the prism mounting section 330 with high mounting accuracy. Therefore, the light from the light source is preferably guided to the objective lens 9 and the return light from the optical recording medium is also suitably guided to the light receiving element 11, so that even if the temperature change is applied to the resin frame 3, the optical head device No. 1 has stable characteristics. Further, the holes 50 (holes 51 and 52) also have an effect of preventing sink when molding the resin frame 3.

The columnar projection 370 formed on the frame side wall 331 of the prism mounting portion 330 is also provided with the hole 52 for making the thickness constant, so that a temperature change is applied to the resin frame 3. Even when the
No local expansion, contraction, etc. occur at zero. Accordingly, the prism 22 is affected by the expansion and contraction of the columnar convex portion 370.
There is no deformation such as a decrease in the verticality of the frame side wall 331 with which the frame abuts. In addition, since the columnar protrusion 370 is not deformed, the holder support member 35 does not tilt even if the holder support member 35 is fixed using the columnar protrusion 370. Therefore, since the objective lens 9 is always supported in a suitable state, the optical characteristics of the optical head device 1 do not deteriorate.

(Other Embodiments) In the above embodiment, holes are formed on both the back side 335 of the frame side wall 331 of the prism mounting portion 330 and the back side of the columnar convex portion 370 extending upward from the frame side wall 331. Although an example in which the first and second frames 51 and 52 are formed has been described, as shown in FIG.
May be formed.

In the above embodiment, the prism mounting section 33
Although the example in which the present invention is applied to 0 is described, since the plurality of optical component mounting portions are formed on the resin frame 3, the present invention is applied to optical component mounting portions other than the prism mounting portion 330. May be.

[0043]

As described above, when a temperature change is applied to the resin frame of the optical head device, the expansion and contraction of the resin in the thick part is intense as compared with the other parts, so that the optical parts are mounted. Although the shape of the portion and the like tend to change, in the present invention, a hole is formed in the back surface of such a frame side wall to make the thickness of the frame side wall uniform. Therefore, even when there is a temperature change in the resin frame, local expansion and contraction do not occur on the frame side wall. Therefore, even if there is a temperature change in the resin frame, the optical components are always mounted on the frame with high mounting accuracy, and the optical head device has stable characteristics. In addition, the hole
There is also an effect of preventing sink when molding the resin frame.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of an optical head device to which the present invention is applied.

FIGS. 2A, 2B, 2C, and 2D are a plan view, a left side view, a right side view, and a bottom view of an optical head device to which the present invention is applied, respectively.

3A, 3B, 3C, and 3D are a plan view, a left side view, a right side view, and a bottom view of a resin frame used for the optical head device shown in FIG. 2, respectively. It is.

4 is an enlarged view of the resin frame used in the optical head device shown in FIG. 1 when the prism mounting portion is viewed from the inside of the resin frame (the direction of arrow X in FIG. 3A). It is a perspective view.

FIGS. 5A and 5B are a perspective view and a side view, respectively, of the prism mounting unit shown in FIG. 3 as viewed from the back side.

FIGS. 6A and 6B are cross-sectional views showing a state where the frame side wall of the prism mounting portion is cut at a position corresponding to the line AA ′ in FIG. 5B, and FIGS. FIG. 6 is a cross-sectional view showing a state where the columnar protrusion protruding upward is cut at a position corresponding to the line BB ′ in FIG. 5B.

FIG. 7 is an explanatory diagram of another resin frame used in the optical head device to which the present invention is applied.

FIG. 8 is an enlarged perspective view showing a state where a prism mounting portion is viewed from the outside of a resin frame in a resin frame used in a conventional optical head device.

9 (A) and 9 (B) are cross-sectional views showing a state in which a frame side wall of a prism mounting portion is cut in the resin frame shown in FIG. 8, and columnar protrusions protruding upward from the prism mounting portion. It is a cross-sectional view showing a cut state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical head apparatus 2A, 2B Guide shaft 3 Resin frame 4 Laser diode (light source) for DVD 5 Laser diode (light source) for CD 6 Common optical path 7 Collimating lens 8 Start-up mirror 9 Objective lens 10 Sensor lens 11 Light receiving element DESCRIPTION OF SYMBOLS 12 Diffraction grating (optical element) 20 Light guide system 21 Half mirror 22 Prism 35 Holder support member 50, 51, 52 hole 70 Objective lens driving device 71 Lens holder 330 Prism mounting part 331 Frame side wall which prism contacts 335 Back side of frame side wall 370 Columnar convex portion L1 First laser beam L2 Second laser beam L10 Optical axis of first laser beam L20 Optical axis of second laser beam

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Atsushi Hanaoka 5329 Shimosuwa-cho, Suwa-gun, Nagano Prefecture F-term in Sankyo Seiki Seisakusho Co., Ltd. 5D117 AA02 HH12 KK04 5D118 AA06 AA13 BA01 BB01 BB07 DC03 EF05 FB18 5D119 AA36 AA38 BA01 BB01 BB04 JA43 JC03 JC04 NA05

Claims (4)

[Claims] 1. A light source, a lens driving device that drives an objective lens that causes light emitted from the light source to converge on an optical recording medium, a light receiving element for receiving return light from the optical recording medium, And a plurality of optical components for guiding return light from an optical recording medium to the light receiving element, and the plurality of optical components, the light source, the lens driving device, and the light receiving element. In the optical head device having the resin frame, the plurality of optical components mounted on the resin frame on which the plurality of optical components are mounted, respectively, the side wall of the frame where the optical components mounted thereon come into contact. An optical head device comprising at least one optical component mounting portion in which the thickness of the side wall of the frame is made uniform by forming a hole on the back surface side. 2. The light according to claim 1, wherein the optical component mounting portion having a uniform thickness is a prism mounting portion in which a side surface of a prism abuts on a side wall of the frame. Head device. 3. The frame according to claim 1, wherein in the optical component mounting portion in which the thickness is made uniform, a columnar convex portion extends upward from the frame side wall, and the hole is formed in the frame side wall. An optical head device, wherein the optical head device is formed continuously from the back side of the frame side wall to the back side of the columnar projection so that the thickness and the thickness of the columnar projection are made uniform. 4. The lens driving device according to claim 3, wherein the columnar projection is provided with a holder support member that supports the objective lens via a lens holder in the lens driving device so as to be movable in both a tracking direction and a focusing direction. An optical head device, wherein the holder support member mounting section is formed by partitioning, and the holder support member disposed on the holder support member mounting section is fixed to the columnar convex portion by an adhesive. .