KR19990020246U - Optical pickup device with optical axis correction - Google Patents

Abstract

The present invention relates to an optical pickup device capable of optical axis correction. This is because when the optical pickup device is mounted on an operating structure such as an automobile, the optical axis does not cross repeatedly according to the motion of the structure, so jitter is improved and the optical efficiency of vibration is kept constant. In order to improve the reliability, the installation hole 30 formed around the inclined groove 15 to which the reflector 20 of the pickup base 10 is attached, the piezoelectric element 35 inserted into the installation hole 30, and A support line 40 connected to the bottom surface of the piezoelectric element 35 and installed through the pick-up base 10, and a gel 45 injected into the bottom surface of the piezoelectric element 35 around the support line 40. In addition, the support line 40 is provided with an optical pickup device capable of optical axis correction comprising a configuration connected to the control circuit. As a result, error correction is performed by repeatedly detecting an inclination of the optical axis generated when the optical pickup device is reproduced by using a piezoelectric element in which displacement is generated by application of a microcurrent, thereby adding an optical axis error at the same time as detecting a tracking error and a focusing error. Since it is corrected by, the occurrence of aberration due to the inclination of the optical axis is significantly lowered, and the light efficiency is increased, thereby improving the reliability of the optical pickup apparatus.

Description

Optical pickup device with optical axis correction

The present invention relates to an optical pickup device capable of optical axis correction. In particular, since the piezoelectric element is installed in the reflector so that the optical pickup device can repeatedly perform optical axis correction when the optical disc is played, the optical axis is corrected to reduce optical aberration and jitter. The present invention relates to an optical pickup apparatus capable of optical axis correction that can be improved to improve reliability.

Generally, a player of an optical recording medium is a device that plays a digital audio disk (DAD) or a digital video disk (DVD) for music reproduction using laser light. An optical pickup device is provided below the recording medium for recording.

The optical pickup device installs an actuator-mounted plate on the pickup base while vertically injecting the laser light downward of the disc, and linearly moves the pickup base in the radial direction of the disc to track the desired track position on the disc. Laser light reflected on the disc at the track position is detected through the optical elements installed in the actuator and the pickup base, and then converted into an electrical signal to reproduce the optical information of the disc.

As an example of such a conventional optical pickup apparatus, as shown in FIG. 1, the pickup base 100 and the light installed on one side of the pickup base 100 emit laser light having a predetermined wavelength and are reflected on the disk. The center of the pickup base 100 is configured to vertically change the holographic optical element 110 for receiving information and the laser light path emitted from the holographic optical element 110 and reflect the reflected light back to the holographic optical element 110. A reflector 120 attached at an angle of 45 DEG and an upper side of the reflector 120 to focus the laser light having the changed optical path on the disk, and to correct the minute difference of the light spot. It consists of an actuator 130 to drive.

Meanwhile, as shown in FIG. 2A, the hologram optical device 110 includes a laser diode 111 in which a laser light having a predetermined wavelength is generated and a laser light formed on and incident on the laser diode 111. By using the diffraction phenomenon, the diffraction grating 113 separating the zeroth order diffraction light and the ± first order diffraction light, that is, the three beams, and the polarization of the incident light passing through the diffraction grating 113 are converted, The hologram prism 115 is formed integrally with the hologram grid 114 for changing the furnace, and is positioned on the optical path changed by the hologram grid 114 of the hologram prism 115 to detect light information and convert the light information into a current signal. It consists of a photodetector 112.

In the operation of the conventional optical pickup apparatus having such a configuration, as shown in FIG. 2B, when a reproduction signal of an optical disc is generated from a controller (not shown), the laser light having a predetermined oscillation wavelength is hologramed on the laser diode 111. The laser beam is incident on the diffraction grating 113 of the prism 115, and the incident laser light passes through the diffraction grating 113 and is separated into zero-order and ± first-order light, that is, three beams, and is radiated. This three beam is used for focusing and tracking errors, and passes through the diffraction grating 113 and goes straight without diffraction via the hologram grating 114. This is because the hologram grid 114 is lattice-processed so as to transmit without diffraction with respect to the polarization of the incident light, so that it is transmitted without diffraction.

Thus, the laser light, which is not diffracted straight, is irradiated from the hologram grid 114, that is, the hologram optical element 110, to the reflector 120 inclined at the center of the pickup base 100. The irradiated laser light is totally reflected from the reflector 120, and the totally reflected laser light is irradiated to the actuator 130 while keeping the optical axis constant.

The laser light irradiated to the actuator 130 is irradiated to the objective lens 135 on the top of the actuator 130, and the laser light is irradiated on the optical disk by the objective lens 135 with different diameters of 1.6 μm to 0.8 μm. The light is collected in a shape and irradiated onto the signal surface of the pit 145 of the video disk 140 or the audio disk 150. The laser light is reflected almost as it is in the absence of the pit 145 on the optical disks 140 and 150. Returning to the lens 135, but where the pit 145 is located, the laser light is diffracted by the pit 145 to be emitted outside the range of the objective lens 135, so that only a part of the incident light is returned. A light quantity difference is generated in the detector 112. This is because the depth of the pit 145 is set to λ / 4 of the wavelength so that the reflected light is half-wavelength depending on the reflection of the pit 145 surface, and is canceled by interference, thereby reducing the amount of light returned to the photodetector 112. Will be.

The modulated reflected light reflected back from the audio disk 150 or the video disk 140 is reflected back from the reflector 120, and the reflected light is incident on the hologram prism 115, and the reflected light is transmitted to the hologram prism 115. The diffraction of the hologram lattice 114 is prevented from irradiating the laser diode 111 again. The diffracted reflected light is sent from the hologram grating 114 to the photodetector 112, and the reflected light modulated by the disk is transmitted to the RF, focus error detection, tracking control and information by the photodetector 112. The converted current is demodulated by the control circuit (not shown) to reproduce the original signal.

Therefore, as described above, the laser light emitted from the laser diode 111 is condensed on the optical disks 140 and 150 in the objective lens 135 in different airy shapes so that the beam focus is formed at different positions so that the optical disk 140 , Information read in 150 may be selectively read, and the incident light and the optical path are different by the hologram grid 114 and are sent to the photodetector 112.

However, in the case where the conventional optical pickup device is mounted on an operation structure such as a vehicle from a mounting base, even if the tracking and focusing errors are compensated from the actuator 130, since the optical axes are repeatedly crossed in accordance with the operation of the structure, optical aberration and There is a problem that the jitter is lowered and the optical efficiency due to vibration is momentarily lowered so that the optical pickup device does not operate in an optimal state.

The present invention was devised in view of the above problems, and when the optical pickup device is mounted on an operating structure such as an automobile, the optical axis does not cross repeatedly according to the operation of the structure, so that jitter is improved and optical efficiency due to vibration is constant. It is an object of the present invention to provide an optical pickup apparatus capable of correcting an optical axis in which the optical pickup apparatus operates in an optimal state and thus improves reliability.

In order to achieve the above object, the present invention provides an installation hole formed around an inclined groove to which a reflector of an optical pickup device pickup base is attached, a piezoelectric element inserted into the installation hole, and a bottom surface of the piezoelectric element. Provided is a support line which is hypothesized to pass through, a gel injected into the bottom surface of the piezoelectric element around the support line, and the support line is connected to a control circuit portion to provide an optical pickup device capable of optical axis correction.

1 is a perspective view of a general optical pickup device;

2A is a partial detailed view of a conventional optical pickup device;

Figure 2b is a schematic view of the operation of the conventional optical pickup,

3 is a perspective view of the present invention,

4 is an operating state of the present invention.

<Explanation of symbols for main parts of drawing>

10: pickup base 15: inclined groove

20: reflector 30: installation worker

35 piezoelectric element 40 support line

45 gel

Hereinafter, the present invention will be described in detail based on the accompanying drawings.

3a and 3b, the installation hole 30 formed around the inclined groove 15 to which the reflector 20 of the optical pickup device pickup base 10 and the pickup base 10 is attached, as shown in FIGS. A piezoelectric element 35 inserted into the installation hole 30, a support line 40 connected to the bottom surface of the piezoelectric element 35 and installed through the pick-up base 10, and a circumference of the support line 40 In the gel 45 is injected into the bottom surface of the piezoelectric element 35 and the support line 40 is made to include a connection to the control circuit.

The piezoelectric element 35 is a magnet of barium titanate ceramics system in which dielectric polarization occurs when mechanical distortion is applied. The piezoelectric element 35 is mainly used for vibration and pressure measurement. It is a ceramic device that can cause mechanical distortion by applying a polarized primary piezoelectric effect and conversely an electric field.

And, the installation hole 30 is perpendicular to the plane of the inclined groove 15 formed in the pickup base 10, that is, the inclination of 45 ° to the left relative to the pickup base 10 to the inner circumference of the pickup base 10 It is formed to a predetermined depth, the through hole 32 through which the support line 40 is formed in the bottom surface of the installation hole (30).

In addition, the support wire 40 is a copper wire-based electric wire capable of vertically supporting a predetermined load with a predetermined tension, and is formed of a material such as a suspension wire that is usually installed in an actuator of an optical pickup device. Is connected to the tracking control circuit of the optical pickup device, and applies a quick pulse signal to the signal applied when the tracking error of the objective lens is corrected to apply power to the support line 40.

Next will be described the operation of the present invention made as described above.

First, as shown in FIG. 4, when a reproduction signal of an optical disc is generated from a control unit (not shown), laser light having a predetermined oscillation wavelength is separated and radiated into a three beam from a hologram optical element (not shown). This three beam is used for focusing and tracking errors and is irradiated from the hologram optical element to the reflector 20 inclined at the center of the pickup base. The laser light thus irradiated is totally reflected from the reflector 20, and the totally reflected laser light is irradiated to the actuator 10 while keeping the optical axis constant.

The laser light irradiated to the actuator 10 is irradiated to the objective lens on the top of the actuator 10, and the laser light is condensed on the optical disc by the objective lens and reflected by the optical disc to generate a light quantity difference in the photodetector. . At this time, the vibration and fine movement of the optical pick-up device is the actuator 10 performs the error correction, the correction of the optical axis is re-generated again by this error correction is as follows.

When the tracking error and focusing error signal is detected by the objective lens, the error is corrected by the operation of the actuator, but the correction of the excessive tracking error and the optical axis which are not corrected by the actuator is performed by the optical axis of the attachment position of the reflector 20. Since fine inclination is to be adjusted, the distortion range is detected from the detection signal of the tracking error obtained when the actuator is driven, and a quick pulse signal is applied to the tracking control circuit. This signal is applied from the tracking control circuit section to the support line 40, which causes the dielectric polarization phenomenon to the piezoelectric element 35 by the support line 40. The dielectric polarization of the piezoelectric element 35 is a secondary piezoelectric effect, which causes mechanical distortion in the piezoelectric element 35, and the mechanical distortion of the piezoelectric element 35 finely adjusts the reflector 20.

When the reflector 20 is finely adjusted as described above, a drop in jitter is detected from the tracking error signal, that is, the inclination of the reflector 20, that is, the tilt of the optical axis, thereby determining that the reflector 20 is tilted from the optical axis. The position is corrected by driving the piezoelectric element 35.

When the error correction of the optical axis is completed by the driving of the reflector 20, the tracking error signal drives the actuator and corrects the normal error signal to reproduce the optical disc. In this case, when the reflector 20 is inclined from the optical axis, the piezoelectric The signal is repeatedly applied to the element 35 to repeat the optical axis correction from the tracking error signal.

Thus, the optical axis can be repeatedly corrected by the reflector 20 by fine driving of the piezoelectric element 35.

On the other hand, since the plurality of piezoelectric elements 35 are provided around the bottom of the reflector 20, for example, at four corners, the signals applied to the plurality of support lines from the tracking control circuit unit are individually applied to install the reflector 20. The state may be adjusted, and the signal applied to the four support lines 40 may be separately installed by a circuit unit that recognizes the error detection signal, and may be adjusted by applying a repetitive signal in which the reflector 20 recognizes and adjusts the tilt from the optical axis.

As described above, the inclination of the reflector 20 can be precisely adjusted by the piezoelectric element 35, and the gel 45 injected into the bottom surface of the piezoelectric element 35 of the installation hole 30 is formed of the piezoelectric element 35. The vibration of the piezoelectric element 35 is absorbed from close distortion and external shock.

Thus, the optical information repeatedly corrected from the reflector 20 is canceled by the interference, so that it is sent to the photodetector, and the reflected light modulated by the disk is transmitted to the RF, focus error detection, tracking control and information by the photodetector. The converted current is demodulated by the control circuit (not shown) to reproduce the original signal.

In this way, the present invention forms an installation hole 30 through which the piezoelectric element 35 is inserted around the inclined groove 15 in which the reflector 20 of the pickup base 10 is installed, thereby signaling the piezoelectric element 35. By applying this, the reflector 20 detects the inclination from the optical axis so that the optical pickup device can stably reproduce.

The optical pickup device capable of optical axis correction has an error correction by repeatedly detecting an inclination of an optical axis generated when the optical pickup device is reproduced by using a piezoelectric element in which displacement is generated by application of a fine current, thereby providing a tracking error and Since the optical axis error is additionally corrected at the same time as the focusing error detection, the occurrence of aberration due to the inclination of the optical axis is significantly reduced, and the light efficiency is increased, thereby improving the reliability of the optical pickup apparatus.

Claims (1)

In the pickup base 10 of the optical pickup device, An installation hole 30 formed around the inclined groove 15 to which the reflector 20 of the pickup base 10 is attached, a piezoelectric element 35 inserted into the installation hole 30, and the piezoelectric element 35. A support line 40 connected to a bottom of the support base and penetrated through the pickup base 10, a gel 45 injected into the bottom of the piezoelectric element 35 around the support line 40, and the support line 40) The optical pickup device capable of correcting the optical axis, characterized in that comprises a configuration connected to the control circuit.