KR100268474B1 - Apparatus for clearing offset of spindle servo in optical diskplayer - Google Patents

Abstract

PURPOSE: An eliminating device for a spindle servo offset is provided to compensate for a spindle offset difference between a CD and a VCD detected by an optical pickup. CONSTITUTION: An optical pickup unit(111) detects data recorded on a CD and a VCD. A reproducing signal of the CD maintains uniform an optical output of a laser diode by the first APC/AFC(Automatic Power Control/Automotive focus Control) detect unit(112). The detected data is amplified by a first amplify unit(113) for a first filter(114) to eliminate noise. A reproducing signal of the VCD is filtered by a second APC/AFC detect unit(122) , a second amplify unit(123), and a second filter(124). Signals from first and second APC/AFC detect units are compared with each other in an offset comparator(115) for detecting difference in offsets. A compensated offset is inputted to the second amplify unit. A CD spindle offset value and a VCD spindle offset value are identified for being amplified by a third amplify unit(116). A motor drive unit(117) rotates a spindle motor(118).

Description

Spindle Servo Offset Remover for Optical Disc Player

The present invention relates to a spindle servo offset removing device of an optical disc reproducing apparatus, and more particularly, to a spindle servo offset removing device of an optical disc reproducing apparatus which compensates and removes a spindle offset difference value of CD and VCD optical discs detected by an optical pickup. It is about.

In general, a compact disc (CD) is a type of disc that records digital signals on aluminum discs and wraps the media in plastic. CD is used as a storage medium that can reproduce the recorded signal by reading the reflected light to the laser beam.

A storage medium that can play back the laser beam by reading the reflected light from the disk is a DVD (Digital Video Disk), which is a large-capacity medium capable of storing several gigabytes of data including moving images on an optical disk. In the next generation DVD, MPEG-II-compressed digital video will be stored for more than 2 hours to develop into high quality and high quality multimedia.

1 is a view showing a state in which data is recorded on a general CD and a DVD.

As shown, the disc information can be obtained by the uneven surface called the pit. In the case of a CD, the minimum size of the pit is M and N, whereas the DVD is M 'and N', which is less than half of a CD. Because of their small size, DVDs can store more data.

The thickness of the current CD is the same as that of the DVD. Here, the same thickness of the disk, that is, the same thickness of the substrate, means that the distance from the surface of the disk to the reflective film is the same.

Therefore, the present optical disc player capable of DVD playback can also play CD. The above-described optical disc player can determine whether the optical disc mounted on the deck is a CD or a DVD, and the control unit provided in the optical disc player determines the internal system to the deck. The mounted optical disc is controlled according to the type.

2 is a configuration diagram and an operation procedure related to the spindle servo offset removing device of the conventional optical disc player.

First, the optical pickup section 11, which picks up an RF signal by reproducing data recorded on an optical disk for CD / DVD, and the CD playback signal input from the optical pickup section 11, always keeps the optical output of the laser diode constant. Low pass after the noise is removed by the first APC / AFC (Automatic Power Control / Automative Focus Control) detector 12 that is held and the noise is removed through the first amplifier 13 that amplifies the detected data to a predetermined level. The first filter 14 is a low pass filter.

In addition, the reproduction signal for DVD input from the optical pickup section 11 is detected by the second APC / AFC detector 22 which always maintains the constant optical output of the laser diode, and the second APC / AFC detector 22 After removing the noise through the second amplifying unit 23 amplified data detected by the predetermined level to a predetermined level, it is filtered by a second filter 24 which is a low pass filter.

In the next step, the third amplifier 16 compensates for the difference between the spindle offset value of the signal reproduced from the CD and the spindle offset value of the signal reproduced from the DVD by the offset compensation circuit 15 and amplifies the compensated offset value. And, through the motor driving unit 17 for controlling the compensated offset value, thereby the spindle motor 18 is moved by the compensation value.

However, there is a problem in that a complicated and expensive offset compensation circuit must be used when offset difference compensation is performed with the above system.

Accordingly, an object of the present invention is to provide a spindle servo offset removing device of an optical disc reproducing apparatus that compensates for the spindle offset difference values of CD and VCD optical discs detected by the optical pickup so as to solve the above problems.

1 is a view showing a state in which data is recorded on a general CD and DVD,

2 is a block diagram of a spindle servo offset removing device of a conventional optical disc player;

3 is a block diagram of the spindle servo offset removing apparatus of the optical disk player according to the present invention.

<Explanation of symbols for main parts of drawing>

112: first APC / AFC detector 115: offset comparator

116: third amplifying unit 122: second APC / AFC detection unit

123: second amplifier

The spindle servo offset removing device of the optical disc player according to the present invention for achieving the above object is an optical pickup unit for picking up data recorded on optical discs for CD and DVD, and a first playback signal for always keeping the CD playback signal constant. An APC / AFC detector, a first amplifier that amplifies the data detected by the first APC / AFC detector to a predetermined level, a first filter that is low-pass filtered after removing noise through the first amplifier, and the optical type A second APC / AFC detector that keeps the DVD output signal picked up from the pickup unit constant at all times, and a second amplification that amplifies the data detected by the second APC / AFC detector to a predetermined level; And a second filter obtained by removing the noise through the second amplifier and performing low pass filtering, and the offset difference values output from the first APC / AFC detector and the second APC / AFC detector. An offset comparator for compensating for the difference value and inputting it to the second amplifier, a third amplifier for amplifying the same adjusted offset value again, a motor driver for driving the spindle motor, and a rotating spindle motor accordingly. It is done.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram of a spindle servo offset removing apparatus of the optical disk player according to the present invention.

An optical pick-up unit 111 for picking up data recorded on an optical disc for CD and DVD, and a first APC / AFC for maintaining a constant optical output of a laser diode for a CD reproduction signal input from the optical pick-up unit 111; After removing the noise through the detector 112, the first amplifier 113 amplifying the data detected by the first APC / AFC detector 122 to a predetermined level, and the first amplifier 113, A first filter 114 that has been pass-filtered, a second APC / AFC detector 122 which keeps the optical output of the laser diode constant at all times for the reproduction signal for DVD picked up from the optical pickup section 111, and the second The second filter 124 which removes the noise through the second amplifier 123 amplifying the data detected by the APC / AFC detector 122 to a predetermined level and the second amplifier 123 and then performs low pass filtering. ) And an offset difference output from the first APC / AFC detector 112 and the second APC / AFC detector 122. And the offset comparator 115 for compensating for the difference value and inputting it to the second amplifier 123, and the CD spindle offset value of the first filter 114 and the DVD of the second filter 124, which are equally adjusted. And a third amplifier 116 in which the spindle offset value is amplified again, a motor driver 117 for driving the spindle motor with the amplified signal, and a rotating spindle motor 118 accordingly.

The operating principle of the present invention configured as described above is described with reference to FIG. 3 as follows.

First, data recorded on the optical disc for CD and DVD is picked up by the optical pick-up unit 111, and the picked-up CD reproduction signal is always kept constant by the first APC / AFC detection unit 112 with the light output of the laser diode. do. The detected data is amplified to a predetermined level by the first amplifier 113, and noise is removed and filtered by the first filter 114.

In addition, the reproduction signal for DVD picked up from the optical pickup section 111 is also filtered by the second APC / AFC detector 122, the second amplifier 123, and the second filter 124.

Unlike the conventional method, the offset difference value is compared by comparing the signals output from the first APC / AFC detection unit 112 and the second APC / AFC detection unit 122 with the offset comparator 115, and the offset value is determined by the difference value. Compensation is made again to the second amplifier 123.

The CD spindle offset value of the first filter 114 and the DVD spindle offset value of the second filter 124 which are equally adjusted are again amplified by the third amplifier 116 and controlled by the motor driver 117. Spindle motor 118 rotates.

Therefore, the present invention finally outputs the same offset value to the third amplification unit, so that it can be controlled as an offset comparator instead of a separate offset compensation circuit, thereby reducing the complexity and cost of the offset compensation circuit.

Claims (1)

An apparatus for removing spindle servo offset of an optical disc player, comprising: an optical pickup unit for picking up data recorded on an optical disc for CD and DVD; A first APC / AFC detector which always maintains a constant reproduction signal for CD picked up from the optical pickup section; A first amplifier which amplifies the data detected by the first APC / AFC detector to a predetermined level; A first filter which performs low pass filtering after removing noise through the first amplifier; A second APC / AFC detector which always keeps the playback signal for DVD picked up from the optical pickup section constant; A second amplifier amplifying data detected by the second APC / AFC detector to a predetermined level; A second filter subjected to low pass filtering after removing noise through the second amplifier; An offset comparator for comparing the offset difference values output from the first APC / AFC detector and the second APC / AFC detector, compensating for the difference value, and inputting the difference to the second amplifier; A third amplifier connected to the first filter and the second filter to amplify the same adjusted offset value again; Spindle servo offset removing device of an optical disc reproducing apparatus, characterized in that the motor drive unit for driving the spindle motor in response to the signal of the third amplifier.

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