JPH04283427A - Optical pickup head assembling device - Google Patents

Abstract

PURPOSE:To offer the assembling device of an optical pickup head by which an optical pickup head device which can detect a stable and satisfactory signal can be offered, as for the assembling device of the optical pickup head which can record, reproduce, and cancel optical information. CONSTITUTION:An actuator constituted of a coil 95 and a magnet 96 which displaces an optical recording medium 40 while keeping an angle between an optical axis 72 and the optical recording medium 40 to be 90 degrees, is provided in the optical axis direction of a beam emitted from the optical pickup head device, so that the optical axis of the beam reflected on the optical recording medium 40 can be stabilized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembly apparatus for an optical pickup head capable of recording, reproducing, or erasing optical information.

0002

[Prior Art] Optical memory technology that uses optical disks with pit-like patterns as high-density, large-capacity storage media includes digital audio disks, video disks,
It has been put into practical use with expanded uses, including document file disks and even data files. The mechanism by which the recording and reproducing of information on an optical disk through a light beam focused on the micron order is successfully performed with high reliability depends solely on the optical system.

FIG. 7 shows a conventional example of an optical pickup head device and an optical pickup head assembly device. Figure 7 (a
), a semiconductor laser light source 1, a condensing lens 2, a semi-transmissive semi-reflective film 3, a photodetector 5, a coil 91, a coil 92
, a magnet 93, a magnet 94, a housing 6 that holds the light source 1, the semi-transparent and semi-reflective film 3, the photodetector 5, and the coils 91 and 92 constitute an optical pickup head device.
It is fixed so that it does not move at 0 and 11. The coherent beam 70 emitted from the light source 1 is reflected by the semi-transmissive/semi-reflective film 3 with an intensity of approximately 50%, guided to the finite objective lens 2, and focused onto the optical storage medium 4. In the optical storage medium 4, 41 is a substrate, and 42 is a protective film. After the beam 70 reflected and diffracted by the optical storage medium 4 passes through the lens 2 again, a beam 71 with an intensity of approximately 50% passes through the semi-transmissive and semi-reflective film 3 and enters the photodetector 5. Magnets 93 and 94 are fixed to the lens 2. The coil 91 and magnet 93 and the coil 92 and magnet 94 each constitute an actuator for focusing and tracking, and are controlled using a focus error signal and a tracking error signal detected from the photodetector 5. . Generally, the positions of the light source 1 and the photodetector 5 that make up the optical pickup head device need to be arranged with precision on the order of microns. The mounting position of the detector 5 is fixed after being finely adjusted on the order of microns so that the best signal can be detected. When assembling and adjusting the optical pickup head device, the optical storage medium 4 is held between the holders 8 and 9 of the motor 7 and the rotation shaft 8 of the motor 7 is held.
0 and is rotated. At this time, the optical storage medium 4
The holder 8 and the optical storage medium 4 An object of a desired thickness is inserted between the rotation axis 80 and the optical storage medium 4 so that changes in the focus error signal and the tracking error signal can be clearly seen. Figure 7
(b) is a top view of a photodetector 5 constituting an optical pickup head device, and an arithmetic circuit 21 for detecting a focus error signal constituting an optical pickup head assembly device;
an arithmetic circuit 22 for detecting a tracking error signal;
An arithmetic circuit 23 for detecting a signal for controlling the motor 7 from a high frequency information signal is shown. Photodetector 5
consists of photodetectors 501, 502, 503, 504,
The focus error signal is obtained by the astigmatism method, and the tracking error signal is obtained by the phase difference method. Arithmetic circuits 21, 22, 2
3, the control signal obtained by the motor 7 and the coil 91
, 92, but may be shut off by switches 81, 82, and 83 as necessary during assembly and adjustment.

0004

[Problem to be solved by the invention] However, the light source 1
When assembling an optical pickup head device that requires positional accuracy on the order of microns for mounting the photodetector 5, it is necessary to create a desired position between the holder 8 and the optical storage medium 4 in order to find the maximum amplitude of the focus error signal. When an object with a thickness of The angle formed by the optical storage medium 4 also changes at the same time. As a result, the optical axis of the beam before being reflected by the optical storage medium 4 and the optical axis of the beam after being reflected by the optical storage medium do not match,
There was a problem that the photodetector 5 could not be fixed at an optimal position.

[0005] Furthermore, there is an optical pickup head device configured to allow a casing in which all optical components such as a light source, a photodetector, and a lens are attached to follow the surface runout and eccentricity of an optical storage medium. has recently been disclosed, and since the casing of such an optical pickup head device moves during servo operation, the light source and photodetector must be adjusted and fixed to the casing using conventional assembly equipment. was impossible.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides an actuator that displaces a beam emitted from an optical pickup head device in a direction in which the optical axis of the beam is elongated, and a beam emitted from the optical pickup head device. An actuator for displacing the optical storage medium in a direction perpendicular to the optical axis of the beam is provided on the holder that holds the optical storage medium, so that the angle between the optical axis of the beam emitted from the optical pickup head device and the optical storage medium is 90 degrees. To enable displacement to be applied to an optical storage medium while maintaining the same.

[0007]

[Operation] By using the above means, it is possible to match the optical axis of the beam before it enters the optical storage medium with the optical axis of the beam after it is reflected by the optical storage medium, so that the optical axis of the beam before it enters the optical storage medium can be made to coincide with the optical axis of the beam after it is reflected by the optical storage medium. Since the optical axis of the beam can be set in the designed direction, accurate position adjustment of the photodetector is possible.

Furthermore, by controlling the displacement of the optical storage medium using the focus error signal and tracking error signal output from the optical pickup head device, the light source, photodetector, lens, etc. that constitute the optical pickup head device can be controlled. Optical pickups with this configuration can perform servo operation while the housing of the optical pickup head device is configured so that the housing in which all optical components are attached follows the surface deflection and eccentricity of the optical storage medium. It becomes possible to adjust the light source and photodetector that constitute the head device.

[0009]

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a schematic diagram of an optical pickup head assembly apparatus according to a first embodiment of the present invention. Components to which the same components as in FIG. 7 can be applied are given the same numbers. In FIG. 1(a), a semiconductor laser light source 1 that emits a coherent beam 70 (for example, wavelength λ=780n
m), condensing lens 2, semi-transparent semi-reflective film 3, photodetector 5,
Coils 91 and 92, magnets 93 and 94, light source 1, semi-transmissive and semi-reflective film 3, photodetector 5, and housing 6 that holds coils 91 and 92 constitute an optical pickup head device.
The housing 6 is fixed with holders 10 and 11 so that it does not move. The beam 70 emitted from the light source 1 passes through the semi-transparent and semi-reflective film 3
A beam with an intensity of about 50% is reflected and guided to the finite system objective lens 2, and focused on the optical storage medium 40. In the optical storage medium 40, 41 is a substrate and 42 is a protective film. After the beam 70 reflected and diffracted by the optical storage medium 40 passes through the lens 2 again, a beam 71 with an intensity of about 50% passes through the semi-transmissive and semi-reflective film 3 and enters the photodetector 5. Magnets 93 and 94 are fixed to the lens 2. The coil 91 and magnet 93 and the coil 92 and magnet 94 constitute actuators for performing focusing and tracking, respectively. The positions of the light source 1 and photodetector 5 that make up the optical pickup head device need to be arranged with precision on the order of microns, so when assembling the optical pickup head device, the light source 1 and the photodetector 5 Finely adjust the mounting position on the micron order so that the best signal is detected, then fix. Optical storage medium 40
is held between the holders 9 and 84, and the holder 84 is further provided with an actuator consisting of a coil 95 and a magnet 96. Here, the angle between the optical storage medium 40 and the designed optical axis of the optical pickup head device is set to 90 degrees with mechanical precision. By applying a signal from the signal generator 12, the coil 95 rotates the optical storage medium 40 while maintaining the angle between the optical storage medium 40 and the optical axis 72 of the beam emitted from the optical pickup head device at 90 degrees. Make me look confused. That is, by using an actuator consisting of a coil 95 and a magnet 96 to displace the holder 84 in the direction (Z direction) in which the optical axis 72 of the beam emitted from the optical pickup head device is extended,
The optical storage medium 40 can be moved in the direction in which the optical axis 72 extends while maintaining the angle between the optical axis 72 of the beam emitted from the optical pickup head device and the optical storage medium 40 at 90 degrees. As a result, the optical axis of the beam before being reflected by the optical storage medium 40 and the optical axis of the beam after being reflected by the optical storage medium 40 can be made to coincide, and when assembling and adjusting the optical pickup head device, Since it becomes possible to adjust and fix the photodetector 5 to the designed beam position, it becomes possible to provide an optical pickup head device capable of stable signal detection. To adjust the photodetector 5, as shown in FIG. The photodetector 5 may be moved within a plane orthogonal to the optical axis of the beam 71 so that the change in the focus error signal that changes depending on the shake is maximized. In addition, here 501, 502, 503, 504
Although a configuration is shown in which a focus error signal is detected by an astigmatism method using a photodetector 5 having four photodetection sections consisting of It goes without saying that the optical pickup head assembly device of the present invention can be applied to the optical pickup head device of the present invention. Furthermore, it is also possible to use a reflecting mirror in which no pits or grooves are recorded on the optical storage medium 40. Although an example in which the actuator is constructed of a coil and a magnet is shown here, it is of course possible to use an actuator based on other principles such as a piezoelectric element or a piezo element. Further, in this embodiment, the angle between the optical storage medium 40 and the designed optical axis of the optical pickup head device is adjusted to 90 degrees with mechanical precision, but if more detailed adjustment is required, For example, the holding body 84 may be provided with an angle adjustment mechanism to perform the adjustment.

FIG. 2 is a schematic diagram of an optical pickup head assembly apparatus according to a second embodiment of the present invention. In the optical pickup head assembly device shown in the first embodiment, the optical axis is extended while always maintaining the angle between the optical axis 72 of the beam 70 emitted from the optical pickup head device and the optical storage medium 40 at 90 degrees. optical storage medium 40 in the direction (Z direction)
However, in the optical pickup head assembly apparatus shown in this embodiment, the pit row direction recorded on the optical storage medium 40 perpendicular to the optical axis 72 is provided. A second actuator consisting of a coil 97 and a magnet 98 that also displaces the optical storage medium 40 (in the Y direction), and a direction perpendicular to both the optical axis 72 and the direction of displacement given by the second actuator, that is, the optical storage medium The optical storage medium 4 is also
A third actuator consisting of a coil 99 and a magnet 100 is provided to displace 0. 21 shown in FIG. 2(b),
22 and 23 are arithmetic circuits for obtaining a focus error signal, a tracking error signal, and a high frequency information signal, respectively. Here, the coil 98 constituting the second actuator
A voltage from the signal generator 13 is applied to. Furthermore, by supplying the focus error signal and tracking error signal obtained from the arithmetic circuits 21 and 22 to the first and second actuators as necessary, any optical system constituting the optical pickup head device can be fixed. Thus, focus and tracking servo operations can be performed, and the position of the photodetector constituting the optical pickup head device can be stably adjusted. Therefore, it is possible to easily assemble and adjust an optical pickup head device having an optical system that performs focus and tracking servo by driving all the optical systems together, as shown in, for example, Japanese Patent Application No. 2-167673. become. Also in the optical pickup head device shown in this embodiment, all the optical components constituting the optical system, such as the light source 1, semi-transmissive and semi-reflective film 3, lens 2, and photodetector 5, are attached to the housing 60. The housing 60 has a coil 101
The actuator consisting of a magnet 102, a coil 103, and a magnet 104 is configured to perform focus and tracking servo operations, respectively. However, when assembling the optical pickup head device, the housing 60 is connected to the holder 14 and the holder. 15, and the light source 1 and photodetector 5 are adjusted using the assembly apparatus of the present invention. Note that it is of course possible to use the optical pickup head assembly device shown in this embodiment for assembling a conventional optical pickup head device, and in this case, the optical pickup head assembly device shown in the first embodiment can be used. You can get the same effect.

FIG. 3(a) shows an example of an optical storage medium 40 constituting the optical pickup head assembly apparatus of the present invention. In this medium, a row of pits 43 having a depth of about 1/5 of the wavelength of the light source are recorded linearly, as shown in FIG. 3(b), as in a general compact disc. The outputs of the signal generators 12 and 13 that apply voltage to the actuator of the optical pickup head assembly device shown in FIG. 1 or 2 have a sawtooth waveform as shown in FIG. By triggering an oscilloscope for observing signals, it becomes possible to assemble and adjust the optical pickup head device while stably observing regular signals.

FIG. 5 shows another example of the optical storage medium constituting the optical pickup head assembly apparatus of the present invention. In this optical storage medium 44, rows of pits 43 having a depth of about 1/5 of the wavelength of the light source are recorded concentrically, similar to a compact disc. Although an example in which rows of pits 43 are recorded is shown here, an optical storage medium in which a lattice of continuous grooves is recorded may also be used.

FIG. 6 shows a third embodiment of the present invention. Since the optical storage medium 44 shown in FIG. 5 is used here, the motor 7 is used instead of the second actuator (coil 97 and magnet 98) in FIG. 2. A holder 8 for holding the optical storage medium 44 is formed on the rotating shaft 80, and the optical storage medium 44 is held by pressing the optical storage medium 44 with the holder 9. The center of the concentric circles formed by the pit rows recorded on the optical storage medium 44 and the center of the rotating shaft 80 of the motor 7 are generally made to coincide. This motor 7 has a similar configuration to a disk rotating section in a normal optical disk device. Optical storage medium 4
4 by the motor 7, this optical pickup head assembly device can continuously obtain high-frequency information signals in the same way as an actual optical disk device, and the position of the photodetector constituting the optical pickup head device can be determined. It can be adjusted and fixed to obtain the optimum high frequency information signal. At this time, as in the previous embodiment, the optical storage medium can be displaced while the angle between the optical axis of the beam emitted from the optical pickup head device and the optical storage medium is always maintained at 90 degrees. Therefore, it is possible to provide an optical pickup head device that can perform adjustment under ideal conditions and can perform stable signal detection. Furthermore, even if the optical pickup head assembly apparatus of the present invention is used, it is also possible to assemble an optical pickup head apparatus having an optical system that performs focus and tracking servo by driving all the optical systems together, which was impossible with conventional assembly apparatuses. Adjustments can be made easily.

[0014]

Effects of the Invention The present invention provides an actuator that displaces the beam emitted from the optical pickup head device in the direction in which the optical axis is elongated, and an actuator that displaces the beam emitted from the optical pickup head device in the direction perpendicular to the optical axis. An actuator is provided on a holder that holds the optical storage medium, so that the optical storage medium is displaced while maintaining the angle between the optical axis of the beam emitted from the optical pickup head device and the optical storage medium at 90 degrees. This has the following effects.

(1) Since it is possible to align the optical axis of the beam incident on the photodetector in the designed direction, accurate position adjustment of the photodetector is possible, and stable and good signal detection is possible. This makes it possible to provide an optical pickup head device.

(2) It becomes possible to easily assemble and adjust an optical pickup head device having an optical system that performs focus and tracking servo by driving all the optical systems together.

[Brief explanation of the drawing]

FIG. 1 (a) is a configuration diagram of an optical pickup head assembly apparatus showing an embodiment of the present invention. (b) It is a top view of the arithmetic circuit which comprises the optical pick-up head assembly apparatus shown in the same figure (a), and the photodetector which comprises an optical pick-up head apparatus.

FIG. 2(a) is a configuration diagram of an optical pickup head assembly apparatus showing another embodiment of the present invention. (b) It is a top view of the arithmetic circuit which comprises the optical pick-up head assembly apparatus shown in the same figure (a), and the photodetector which comprises an optical pick-up head apparatus.

FIG. 3(a) is an example of a configuration diagram of an optical storage medium that constitutes the optical pickup head assembly apparatus of the present invention. (b) An example of a pit string recorded on an optical storage medium.

FIG. 4 is an example of a signal waveform for driving an actuator constituting the optical pickup head assembly device of the present invention.

FIG. 5 is another example of a configuration diagram of an optical storage medium that constitutes the optical pickup head assembly device of the present invention.

FIG. 6(a) is a configuration diagram of an optical pickup head assembly apparatus showing still another embodiment of the present invention. (b) It is a top view of the arithmetic circuit which comprises the optical pick-up head assembly apparatus shown in the same figure (a), and the photodetector which comprises an optical pick-up head apparatus.

FIG. 7(a) is a configuration diagram showing an example of a conventional optical pickup head assembly device. (b) It is a top view of the arithmetic circuit which comprises the optical pick-up head assembly apparatus shown in the same figure (a), and the photodetector which comprises an optical pick-up head apparatus.

[Explanation of symbols]

1. Light source 2 Condensing lens 3 Semi-transparent and semi-reflective film 4 Optical storage medium 5 Photodetector 6 Housing 7 Motor 8 Holding body 9 Holding body 10 Holding body 11 Holding body 12 Signal generator 13 Signal generator 14 Holding body 15 Holding body 21 Arithmetic circuit 22 Arithmetic circuit 23 Arithmetic circuit 40 Optical storage medium 41　Substrate 42 Protective film 43 Pit 44 Optical storage medium 60 Housing 70 beam 71 Beam 72 Optical axis 80 Rotation axis 81 Switch 82 Switch 83 Switch 84 Holding body 91 Coil 92 Coil 93 Magnet 94 Magnet 95 coil 96 magnet 97 Coil 98 magnet 99 coil 100 magnet 101 Coil 102 Magnet 103 Coil 104 Magnet 501 Photo detection section 502 Photo detection section 503 Photo detection section 504 Photo detection section

Claims (3)

[Claims] 1. A semiconductor laser light source that emits a coherent beam or a quasi-monochromatic beam, a condensing optical system that receives the beam from the light source and focuses it on a minute spot onto an optical storage medium, and is reflected and diffracted by the optical storage medium. a photodetector having a plurality of photodetectors for receiving the beam and outputting a photocurrent; and an optical branching element for branching the beam reflected and diffracted by the optical storage medium and guiding the beam to the photodetector. a holder for holding an optical pickup head device, an optical storage medium that reflects and diffracts the beam emitted from the optical pickup head device, and an optical storage medium for holding the optical storage medium and emitted from the optical pickup head device. An optical pickup head assembly apparatus comprising an actuator that displaces the optical storage medium in the optical axis direction while maintaining an angle of 90 degrees between the optical axis of the beam and the optical storage medium. 2. A semiconductor laser light source that emits a coherent beam or a quasi-monochromatic beam; a condensing optical system that receives the beam from the light source and focuses it on a minute spot onto an optical storage medium; and a beam that is reflected and diffracted by the optical storage medium. a photodetector having a plurality of photodetectors for receiving the beam and outputting a photocurrent; and an optical branching element for branching the beam reflected and diffracted by the optical storage medium and guiding the beam to the photodetector. a holder for holding an optical pickup head device, an optical storage medium that reflects and diffracts the beam emitted from the optical pickup head device, and an optical storage medium for holding the optical storage medium and emitted from the optical pickup head device. A first step of displacing the optical storage medium in the optical axis direction while maintaining an angle of 90 degrees between the optical axis of the beam and the optical storage medium.
a second actuator that displaces the optical storage medium in a direction perpendicular to the optical axis; and a second actuator that displaces the optical storage medium in a direction perpendicular to the optical axis and the direction of displacement by the second actuator, respectively. 3rd to let
An optical pickup head assembly device characterized by comprising an actuator. 3. A semiconductor laser light source that emits a coherent beam or a quasi-monochromatic beam, a condensing optical system that receives the beam from the light source and focuses it on a minute spot onto an optical storage medium, and is reflected and diffracted by the optical storage medium. a photodetector having a plurality of photodetectors for receiving the beam and outputting a photocurrent; and an optical branching element for branching the beam reflected and diffracted by the optical storage medium and guiding the beam to the photodetector. a holder for holding an optical pickup head device, an optical storage medium that reflects and diffracts the beam emitted from the optical pickup head device, and an optical storage medium for holding the optical storage medium and emitted from the optical pickup head device. a first actuator that displaces the optical storage medium in the optical axis direction while maintaining an angle between the optical axis of the beam and the optical storage medium at 90 degrees; and a first actuator that displaces the optical storage medium in a direction perpendicular to the optical axis. An optical pickup head assembly apparatus comprising: a second actuator for displacing the optical storage medium; and a third actuator for holding and rotating the optical storage medium.