JPH10177739A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make on optical pickup device small sized and thin structive by mounting a superimposing circuit on a recessed part formed in a carriage on the side of mounting an optical unit, covering the superimposing circuit with a metallic plate and fixing an electric supply substrate for an optical unit to this metallic plate. SOLUTION: The carriage 2 is formed with the recessed part 6 on the side of a surface to be arranged with the optical unit, etc., and the superimposing circuit 3 for superimposing a semiconductor laser is arranged in the recessed part 6. The metallic plate 5 consists of a metallic material of stainless steel, copper, brass and iron, etc., for shielding an electromagnetic wave generated from the superimposing circuit 3. The superimposing circuit 3 is held by the plate 5 and the carriage 2 between them, and also parts for supplying electric power and transmitting and receiving a signal are retained by them as well. Since the superimposing circuit 3 is not projected out of the carriage, shielding the superimposing circuit 3 and fixing the electric supply substrate 4 for the optical unit can be performed by one plate 5, thus making the carriage small size and thin structive and light in weight. Consequently, the carriage is movable at high speed, and the optical pickup device is miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-density disc,
The present invention relates to an optical pickup device used for recording and reproduction on an optical disk such as a compact disk.

[0002]

2. Description of the Related Art A conventional optical pickup for recording / reproducing a high density recording disk and a compact disk will be described below. FIG. 3 is a front view of a conventional optical pickup device, and FIG. 4 is a sectional view taken along the line BB of FIG.

Reference numeral 9 denotes a semiconductor laser which emits a laser beam having a wavelength of 635 to 650 nm, which is an optical unit integrally formed with a three-divided diffraction grating for guiding the reflected light from the optical disk 15 to a detector and a six-divided light receiving element. It is. 1
Reference numeral 0 denotes a photodetector comprising a semiconductor laser that emits laser light having a wavelength of 780 nm, a diffraction grating that generates three beams from the semiconductor laser light, a two-division diffraction grating that guides reflected light from the optical disk 15 to a detector, and a five-division light receiving element. Are integrated optical units. The optical unit 9 and the optical unit 10 are arranged so as to be orthogonal to each other, and the center of the beam splitter 16 is arranged on the intersection of the laser emission light of the optical unit 9 and the laser emission light of the optical unit 10. The central portion on the side of the light exit surface is a circular shape through which both light having a wavelength of 635-650 nm and a wavelength of 780 nm at which the numerical aperture of the objective lens becomes 0.43-0.45 are transmitted, and the peripheral portion has a wavelength of 635-650 n.
A wavelength filter that transmits the laser emission light of m and shields the laser emission light of the wavelength of 780 nm is fixed by means such as adhesion. The laser emission light that has passed through the wavelength filter is converted into divergent light by the collimator lens 17, and the laser emission light having a wavelength of 635 to 650 nm is converted to a thickness of 0.6 mm.
Is focused to about 1 μm by an objective lens 29 having a numerical aperture of 0.6 for focusing on a high-density disk.

The arrangement of the optical unit 9 has wavelengths of 635-65.
The optical unit 10 is installed so that the position of the 0 nm laser light source becomes parallel light after passing through the collimator lens 17.
It is arranged at a position closer to the objective lens 7 than the laser light source of 0 nm.

The light emission of the two semiconductor lasers of this optical system is switched according to the optical disk 15 to be reproduced. Thickness 0.
Reproduction operations on optical disks having different thicknesses of 6 mm and 1.2 mm will be described below. When reproducing a signal from the high-density disk 15 having a thickness of 0.6 mm, laser emission light having a wavelength of 635 to 650 nm from a semiconductor laser passes through a diffraction grating and is reflected by a beam splitter 16. Through the objective lens 7. The laser emission light incident on the objective lens 7 forms an image on the high-density disk 15 on a thickness of 0.6 mm by the condensing action of the objective lens 7. The reflected light from the high-density disk 15 is again applied to the objective lens 7, the collimator lens 17,
After being reflected by the beam splitter 16 via the wavelength filter, it is incident on the diffraction grating. The light incident on the diffraction grating is diffracted by the three divided regions of the diffraction grating, and reaches the photodetector. In the above operation, the so-called hologram Foucault method using the first order diffracted light from the semicircular area of the diffraction grating is used as the focus error signal, and the RF signal is detected from the sum of the current output detected by the six-divided light receiving element converted into a voltage signal. To detect. The tracking error signal is obtained by converting the voltage output by the first-order diffracted light of each of the two divided regions of the diffraction grating into a digital waveform by a comparator, and converting a pulse corresponding to the phase difference into an analog waveform through an integration circuit. To detect.

When reproducing a signal from an optical disk 15 having a thickness of 1.2 mm, light having a wavelength of 780 nm from a semiconductor laser is separated into three beams by a diffraction grating and transmitted through the diffraction grating.
After passing through the beam splitter 16 and passing through the central circular portion of the wavelength filter, the collimator lens 17
The light enters the objective lens 7 and forms an image on the optical disk 15 by the condensing action of the objective lens 7. The reflected light from the optical disk 15 again passes through the objective lens 7, the collimator lens 17, the circular portion at the center of the wavelength filter, and the beam splitter 16, and enters the diffraction grating. The light incident on the diffraction grating is diffracted, reaches a photodetector, and detects a signal. The RF signal is detected from the sum of the current output detected by the five-divided light receiving element converted into a voltage signal, and the focus error signal is detected by a so-called hologram Foucault method using first-order diffracted light from a half area of the diffraction grating. The tracking error signal is 3
Detect by beam method.

Reference numeral 8 denotes a volume for adjusting the amount of laser light emitted from the semiconductor laser in the optical unit 9 and is mounted on a laser substrate fixed on the optical unit 9 by means such as soldering. 18 is the optical unit 10
A volume for adjusting the amount of laser light emitted from the semiconductor laser inside, and is mounted on a laser substrate fixed on the optical unit 10 by means such as soldering.
Reference numeral 3 denotes a superimposing circuit for superimposing the semiconductor laser light in the optical unit 9.
2 is mounted on a substrate 106 fixed by means such as soldering or an adhesive.

As described above, the superimposing circuit 3 includes the optical unit 9, the volume 8 mounted on the laser substrate,
In order to avoid the trouble, the structure is added from the outside of the carriage 102, such as being arranged on the upper surface of the carriage 102. Further, in order to shield the electromagnetic wave generated from the superimposing circuit 3,
It is necessary to provide.

[0009]

In the structure of the conventional optical pickup device, the superposition circuit is disposed on the upper surface of the carriage in order to avoid an optical unit, a volume, and the like. Therefore, it has been difficult to reduce the size, thickness, and weight. Further, a metal plate for shielding electromagnetic waves generated from the superimposing circuit is required separately, and there are problems such as an increase in the size of the optical pickup device and an increase in the number of components due to securing a space therefor.

[0010]

SUMMARY OF THE INVENTION The present invention is to solve the problems of the conventional optical pickup. The carriage has a concave portion formed on the surface side on which the optical unit is mounted, and a superimposed circuit is mounted in the concave portion. The conductive plate covers the superimposed circuit and fixes a substrate for supplying electricity to the optical unit at another portion of the plate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to an optical unit having a semiconductor laser for emitting laser light and a photodetector for detecting reflected light from a recording medium, and the optical unit connection. An optical pickup device having a carriage mounted with a substrate for supplying the supplied electricity and a superimposing circuit for superimposing laser light emitted from the optical unit, wherein the carriage has a concave portion on a surface side on which the optical unit is mounted. Is formed, and the superimposing circuit is mounted in the concave portion. The superimposing circuit does not protrude from the carriage, and has an effect of reducing the thickness, size, and weight of the carriage.

According to a second aspect of the present invention, at least one optical unit emits a laser beam having a wavelength of 635 to 650 nm, and the carriage of an optical pickup device having a plurality of optical units is made thinner. Miniaturization,
It has the effect of reducing the weight.

According to a third aspect of the present invention, there is provided an optical unit having a semiconductor laser for emitting a laser beam and a photodetector for detecting reflected light from a recording medium, and an electric unit connected to the optical unit. An optical pickup device having a carriage on which a substrate to be supplied, a superimposing circuit that superimposes laser light emitted from the optical unit, and a plate made of a metal member that shields the superimposing circuit are provided. A concave portion is formed on a surface side on which the optical unit is mounted, and the superimposition circuit is mounted in the concave portion; the plate covers the superposition circuit and fixes the substrate at another portion of the plate; No longer protrudes from the carriage, and the board for supplying electricity to the optical unit and the shield of the superposition circuit can be fixed with one plate, Thinning the ridge has the effect of miniaturization, decreasing the number of parts and weight and to.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a front view of an optical pickup device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG. An optical disk 15 is a high-density optical disk or a compact disk. Reference numeral 13 denotes a spindle motor for rotating the optical disk 15 and a mechanism for clamping the optical disk 15. Reference numeral 2 denotes a carriage on which an optical pickup unit 20 for performing recording and reproduction on the optical disk 15 and the like are mounted. Reference numeral 1 denotes a base on which the spindle motor 13 and the carriage 2 are mounted. Reference numeral 14 denotes a flexible substrate that supplies power to the spindle motor and the optical pickup unit.

In FIG. 1, reference numeral 9 denotes a wavelength of 635-650 n.
An optical unit integrally comprising a semiconductor laser that emits a laser beam of m and a photodetector composed of a three-division grating and a six-division light receiving element that guides reflected light from an optical disk to a detector, and 10 is a laser beam having a wavelength of 780 nm. An optical unit integrally configured with a semiconductor laser that emits light, a diffraction grating that generates three beams from laser light, a photodetector including a two-division diffraction grating that guides reflected light from the optical disk 15 to a detector, and a five-division light receiving element. Are arranged so as to be orthogonal to each other, and the center of the beam splitter 16 is
And the center portion of the beam splitter 16 on the light emitting surface side has a diameter of 0.43 and a numerical aperture of the objective lens of 0.43.
Wavelength 635-650 nm and wavelength 780
The light is a circular shape that transmits both light of nm and the peripheral portion is a wavelength of 63.
Laser emission light of 5 to 650 nm is transmitted and the wavelength is 780 n
The laser output light of m is fixed to a wavelength filter for shielding light by means such as adhesion. The laser emission light that has passed through the wavelength filter is converted into parallel light by a collimator lens 17, and an objective lens having a numerical aperture of 0.6 for condensing laser emission light having a wavelength of 635-650 nm on a high-density disk 15 having a thickness of 0.6 mm. 29 condenses light to about 1 μm.

The arrangement of the optical unit 9 is such that the wavelengths are 635-65.
The optical unit 10 is installed so that the position of the 0 nm laser light source becomes parallel light after passing through the collimator lens 17.
It is arranged at a position closer to the objective lens than the laser light source of 0 nm. For example, assuming that the optical path distances of the semiconductor laser light source having wavelengths of 635-650 nm and 780 nm and the objective lens in the air length are L1 and L2, respectively, 0.55
The arrangement of the optical unit 10 mounted with a semiconductor laser having a wavelength of 780 nm is set in a range of ≦ L2 / L1 ≦ 0.75.

The light emission of the two semiconductor lasers of the present optical system is switched according to the optical disk 15 for recording and reproducing. Reproducing operations on optical disks having different thicknesses of 0.6 mm and 1.2 mm will be described below. 0.6m thick
When reproducing a signal from the high-density disk 15 of m, laser emission light of a wavelength of 635 to 650 nm from a semiconductor laser passes through a diffraction grating, is reflected by a beam splitter 16, and then passes through a wavelength filter and a collimator lens 17. The light enters the objective lens. The laser emission light incident on the objective lens is focused on the high-density disk 15 by a thickness of 0.6 mm by the focusing action of the objective lens. The reflected light from the high-density disk 15 passes through the objective lens, the collimator lens 17, and the wavelength filter again, is reflected by the beam splitter 16, and then enters the diffraction grating. The light incident on the diffraction grating is diffracted by the three divided regions of the diffraction grating, and reaches the photodetector. In the above operation, the RF signal is detected from the sum of the current output detected by the six-divided light receiving element converted into a voltage signal, and the focus error signal is a so-called hologram Foucault using the first-order diffracted light from the semicircular region of the diffraction grating. Method. The tracking error signal is obtained by converting the voltage output by the first-order diffracted light of each of the two divided regions of the diffraction grating into a digital waveform by a comparator, and converting a pulse corresponding to the phase difference into an analog waveform through an integration circuit. To detect.

When reproducing a signal from an optical disk 15 having a thickness of 1.2 mm, a laser beam having a wavelength of 780 nm from a semiconductor laser is split into three beams by a diffraction grating (not shown), passes through the diffraction grating, and passes through a beam splitter 16. The light passes through the substantially circular portion at the center of the wavelength filter, and then enters the collimator lens 17 and the objective lens. The reflected light from the optical disk 15 again passes through the objective lens, the collimator lens 17, the substantially circular portion at the center of the wavelength filter, and the beam splitter 16, and enters the diffraction grating. The light incident on the diffraction grating is diffracted, reaches a photodetector, and detects a signal. The RF signal is detected from the sum of the current output detected by the five-divided light receiving element converted into a voltage signal, and the focus error signal is detected by a so-called hologram Foucault method using first-order diffracted light from a half area of the diffraction grating. The tracking error signal is detected by a three-beam method.

Reference numeral 8 denotes a volume for adjusting the amount of laser emission of the semiconductor laser in the optical unit 9, and reference numeral 18 denotes a volume for adjusting the amount of laser emission of the semiconductor laser in the optical unit 10. Volume 8,
Reference numeral 18 denotes a surface different from the surface on which the optical units 9 and 10 are disposed, and is disposed on the same surface. Reference numeral 3 denotes a superimposing circuit for superimposing the semiconductor laser in the optical unit 9. Reference numeral 12 denotes a screw shaft formed with a spiral groove. Reference numeral 11 denotes a rack formed with a groove that meshes with the groove of the screw shaft 12. The rack 11 has the carriage 2 attached thereto, and the groove of the screw shaft 12 and the groove of the rack 11. Are attached to the screw shaft 12 so that the carriage 2 can move between the outer peripheral side and the inner peripheral side of the optical disk 15 by rotating the screw shaft 12 in the forward and reverse directions.

The carriage 2 is a rack 11 of the carriage 2
On the side where the optical unit 9, the optical unit 10, the beam splitter 16 and the like are arranged,
A recess 6 is formed. A superimposing circuit 3 for superimposing the semiconductor laser of the optical unit 9 is disposed in the concave portion 6, and a substrate 4 attached to the bottom of the concave portion 6 with an adhesive or the like.
Are connected by soldering or the like. Reference numeral 5 denotes a metal plate that shields electromagnetic waves generated from the superimposing circuit 3. The plate 5 is made of a metal material such as stainless steel, copper, brass, or iron, and sandwiches the superimposing circuit 3 between the plate 5 and the carriage 2. The FPC 14 for supplying power to the semiconductor lasers and the like of the optical units 9 and 10 and exchanging signals is held down at other portions sandwiching the superimposing circuit 3 of FIG.

In this embodiment, the concave portion 6 is formed in the carriage 2, but a step may be formed.
Is mounted on the bottom of the carriage 2, but the superimposing circuit 3 may be mounted on the bottom of the carriage 2 with an adhesive resin or the like, and the substrate 4 may be mounted on the other surface side of the superimposing circuit 3.

[0022]

As described above, according to the present invention, the carriage has a concave portion formed on the surface on which the optical unit is mounted, and the superimposed circuit is mounted in the concave portion. By fixing the board that supplies electricity to the optical unit in other parts, the superimposed circuit does not protrude from the carriage, and the board that supplies electricity to the optical unit and the shield of the superimposed circuit is fixed with one plate. The high-speed movement of the carriage is made possible by making the carriage thinner, smaller, and lighter, so that the optical pickup device can be made thinner and smaller, and the speed of recording and reproduction can be increased. Has an excellent effect of reducing the amount of

[Brief description of the drawings]

FIG. 1 is a front view of an optical pickup device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1 according to an embodiment of the present invention;

FIG. 3 is a front view of a conventional optical pickup device.

FIG. 4 is a cross-sectional view of the conventional optical pickup device taken along line BB in FIG. 3;
Sectional view

[Explanation of symbols]

 Reference Signs List 1 base 2 carriage 3 superposition circuit 4, 106 substrate 5, 103, 104 plate 6 concave portion 7 objective lens 8 volume 9, 10 optical unit 11 rack 12 screw shaft 13 spindle motor 14 FPC 15 optical disk 16 beam splitter 17 collimator lens 18 volume 20 Optical pickup unit 101 Base 102 Optical pickup

Claims (3)

[Claims] An optical unit having a semiconductor laser for emitting laser light and a photodetector for detecting reflected light from a recording medium; a substrate connected to the optical unit for supplying electricity; An optical pickup device, comprising: a moving unit mounted and moved with a superimposing circuit for superimposing the emitted laser light, wherein the moving unit has a concave portion formed on a surface side on which the optical unit is mounted, and the concave portion is formed in the concave portion. An optical pickup device comprising a superimposition circuit. 2. The method according to claim 1, wherein the at least one optical unit has a wavelength of 635.
The optical pickup device according to claim 1, wherein the optical pickup device emits a laser beam of up to 650 nm. 3. An optical unit having a semiconductor laser that emits laser light and a photodetector that detects reflected light from a recording medium; a substrate connected to the optical unit for supplying electricity; An optical pickup device comprising: a superimposing circuit for superimposing the emitted laser light; and a moving unit mounted and moved with a plate made of a metal member shielding the superimposed circuit, wherein the moving unit is the optical unit. An optical pickup device, wherein a concave portion is formed on a surface side on which the substrate is mounted, the superimposed circuit is mounted in the concave portion, and the plate covers the superposed circuit and fixes the substrate at another portion of the plate.