KR980011130A - Disc Tracking Condition Determining Device of Optical Pickup - Google Patents

Abstract

When the adjustment of the optical pickup is automatically performed or when it is necessary to know the correlation between the side beam signal and the main beam signal having a time delay of several tens of microseconds, The present invention relates to a disk tracking state discrimination apparatus for an optical pickup capable of automatically adjusting an optical pickup by using this data and also capable of grasping a correlation between a side beam signal and a main beam signal, A photodiode 10 for converting an amount of light for the side beams into an electrical signal, a preamplifier unit (not shown) for converting the analog current signal input to the output terminal of the photodiode 10 into an analog voltage signal And an analog voltage signal connected to the output terminal of the pre-amplifier section 20, And a logic circuit for inputting the side beam SB data and the main beam data MB to the exclusive OR gate EX-OR to output a 7-bit data signal, And a circuit unit 40.

Description

Disc Tracking Condition Determining Device of Optical Pickup

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to determination of an adjustment state of an optical pickup (PICK UP), and more particularly, to a method of determining whether a preceding beam and a main beam of three beams separated by grating are correctly positioned on a track And more particularly, to a disk tracking status determination apparatus for an optical pick-up capable of adjusting an optical pickup by using the optical pickup.

In general, the tracking state of a normal optical pickup is a state in which three beams separated from the grating as shown in FIG. 1 are arranged in a line on one track loaded on the disc, while tracking of abnormal optical pickup State refers to a state in which three beams separated from the grating as shown in FIG. 2 are disposed on different tracks without being arranged in a line on one track of the disk.

Here, the three beams are divided into a side beam and a main beam, which are divided into a leading beam and a trailing beam.

In order to discriminate the tracking state of the optical pickup, conventionally, an analog signal waveform displayed on the oscilloscope screen is visually checked using an oscilloscope to determine the tracking state of the optical pickup.

That is, by setting the signal of the preceding beam among the three beams separated from the grating as the trigger signal of the oscilloscope and setting the data signal of the main beam as the source (SORCE) input, the analog signal waveform displayed on the oscilloscope screen It is determined whether the tracking state of the optical pickup is normal or abnormal.

However, in the conventional discrimination method using the oscilloscope, since the analog signal waveform displayed on the oscilloscope screen can not be seen with the naked eye, there is a problem that it can not provide any assistance in automatically adjusting the optical pickup.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a method for automatically adjusting an optical pickup or a method for correcting a correlation between a main beam signal and a side beam signal having a time delay of several tens of microseconds And to output data that can be used to determine the relationship when it is necessary to know the relationship.

FIG. 1 is a diagram showing a tracking state of a normal optical pickup on a disk track; FIG.

FIG. 2 is a diagram showing a tracking state of an abnormal optical pickup on a disk track; FIG.

FIG. 3 is a configuration diagram of a disc tracking state determining apparatus for an optical pickup according to the present invention.

Description of reference numerals used in the main parts of the drawings

10: photodiode 20: preamplifier section

30: EFM converting section 40: Logic circuit section

MB: main beam SB: side beam

According to an aspect of the present invention, there is provided a light emitting device including: a photodiode for converting an amount of light for a main beam and a side beam into an electrical signal; A preamplifier for converting an analog current signal input to an output terminal of the photodiode into an analog voltage signal; An EFM converter connected to an output terminal of the preamplifier to convert an analog voltage signal into a signal of a digital frequency which is a signal specification of a compact disc; 45 pieces of side beam data are input first in synchronization with a predetermined frequency clock signal, 19 pieces of side beams and main beam data are inputted to the first register and the second register, respectively, starting from the 46th input clock signal , 45 pieces of main beam data are input to the second register, data of 64 registers are input to the exclusive excitation gate, and 7-bit data signals are output to the output terminal of the exclusive OR gate The present invention also provides a disc tracking state determining apparatus for an optical pickup having a circuit section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of an apparatus for determining a disc tracking state of an optical pickup according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a block diagram of a disc tracking state determining apparatus for an optical pickup according to the present invention.

An input terminal of the preamplifier unit 20 is connected to the output terminal of the photodiode 10 for converting the light quantity of the main beam MB and the side beam SB into an electrical signal, Signal.

An input terminal of the EFM converting unit 30 is connected to an output terminal of the preamplifier unit 20 so that an analog voltage signal is converted into a digital frequency signal which is a signal specification of a compact disc.

The light amount data for the main beam MB and the side beam SB frequency-converted by the EFM converting unit 30 are synchronized with the 3 MHz clock signal at the input of the logic circuit unit 40, 45 registers are input to the first register and 19th clock is input to the first register and the second register simultaneously from the clock signal inputted at the 46th clock, and the main beam data is inputted to the second register 45 times And the data of each of the 64 registers is inputted to the exclusive excitation gate to output a 7-bit data signal to the output terminal of the exclusive OR gate.

The operation of the present invention having the above-described configuration will now be described.

First, in order to reproduce data normally using the optical pickup, the grating of the optical pickup must be normally adjusted. That is, as shown in FIG. 1, three beams, which have passed through the grating, As shown in FIG.

If it is not normal, the side beam and the main beam are placed on different tracks of the disk as shown in FIG.

In order to find out the position of the beam, the data of the preceding beam and the main beam must be compared. In the case of the original track state in which the grating is normally adjusted, since the preceding beam and the main beam pass through the same track, do.

In this case, the two signals have a time difference of about 15 mu s at a general CVD rate (1.25 mu m) although they depend on the rotational speed of the disk.

The data processing according to the configuration of the present invention is performed in order to judge whether the two signals having the time difference are identical or not.

The amount of light for the main beam MB and the side beam SB positioned on the track of the disk through the output terminal of the photodiode 10 is converted into an electrical signal in the form of an analog current.

The light amount data for the main beam MB and the side beam SB converted into the electrical signals of the analog current type are input to the preamplifier unit 20 and converted into analog voltage signals.

The data converted into the analog voltage signal is input to the input terminal of the EFM converting unit 30 and converted into a digital frequency signal which is a signal specification of the compact disc.

The EFM converting unit 30 inputs the light amount data of the main beam MB and the side beam SB to the logic circuit unit 40. In synchronization with the 3 MHz clock signal, 45 pieces of data are inputted into the first register and 19 pieces of side beams and main beam data are inputted to the first and second registers from the clock signal inputted at the 46th time, and then 45 pieces of main beam data are inputted to the second register And the data of each of the 64 registers is inputted to the exclusive OR gate EX-OR so that the 7-bit data signal is outputted to the output terminal of the exclusive OR gate.

The tracking state of the optical pickup is determined through the 7-bit data signal thus output.

When the 7-bit data signal is input to the microprocessor (not shown), the optical pickup can be adjusted according to the currently input data signal.

As a result, as described above, the apparatus for discriminating the disc tracking state of an optical pickup according to the present invention, when automatically adjusting the optical pickup, or when the correlation between the side beam signal having a time delay of several tens of microseconds and the main beam signal It is possible to automatically adjust the optical pickup by using this data and also to grasp the correlation between the side beam signal and the main beam signal There is an advantage.

Claims (2)

A photodiode for converting an amount of light for the main beam and the side beam into an electrical signal; A preamplifier connected to an output terminal of the photodiode for converting an input analog current signal into an analog voltage signal; An EFM converter connected to an output terminal of the preamplifier for converting an analog voltage signal into a signal of a digital frequency which is a signal specification of a compact disc; 45 pieces of side beam data are first input to the first register in synchronization with a predetermined frequency clock signal, 19 pieces of side beams and main beam data are simultaneously input to the first register from the clock signal input at the 46th time, And 45 main beam data are input to the second register to input data of each of the 64 registers to the exclusive excitation gate so that 7 bits are output to the output terminal of the exclusive OR gate, And a logic circuit unit for outputting the data signal of the optical pickup. The apparatus of claim 1, wherein the predetermined frequency clock signal has a frequency of 3 MHz. ※ Note: It is disclosed by the contents of the first application.