Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Reexamination Certificate
1998-12-30
2001-03-13
Young, W. R. (Department: 2651)
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
C369S053130, C369S053130
Reexamination Certificate
active
06201774
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for judging an optical disk, and in particular to an improved apparatus for judging an optical disk which makes it possible to judges the type of an optical disk by detecting a phase difference of E and F signals which are two sub-beams detected by an optical pick-up apparatus.
2. Description of the Conventional Art
Generally, the CD (Compact Disk) is formed by coating a writing medium on one side of the same made of an aluminum. This CD is widely used as a storing medium by emitting a laser beam on the side into which the data are written for thereby reproducing the written data.
As the storing medium which is implemented by emitting a laser beam into the side of the same into which the data are written, a DVD (Digital Video Disk) is known. This DVD has a large storing capacity capable of storing few giga bytes of data including motion pictures. In the future, the DVD will be used for storing the digital data compressed based on MPEG-II and for a high resolution and quality multimedia medium which may run for more than two hours.
FIG. 1
is a view illustrating a comparison between the data written into the conventional CD and DVD.
As shown therein, the disk information is obtained from a protruded surface which is called a pit. In the case of the CD, the minimum size of the pit is N, and in the case of the DVD, the minimum size of the pit is N′(an example of relative distance between pits is shown as M). As a result of the comparison therebetween, since the pit of the CD is smaller by half than the same of the DVD, the DVD is capable of storing more data compared to the CD.
The thickness of the CD is the thickness as the same of the DVD. Thus the fact that the thicknesses of the CD and DVD are the same means that the distance between the disk surface and the reflection surface is same in the CD and DVD, respectively.
Therefore, the optical disk reproducing apparatus with a DVD reproducing function has also a CD reproducing function. In this optical disk reproducing apparatus, a controller provided in the optical disk reproducing apparatus judges whether the optical disk mounted is a CD or DVD, so that the operation of the system is controlled based on the type of the optical disk mounted in the deck of the system.
However, in the optical disk reproducing apparatus with the DVD reproducing function, in the case that an optical disk is mounted into the deck, the type of the optical disk mounted in the deck of the system is judged by reproducing a read-in region of the optical disk. In this case, long read-in time is required for reproducing the read-in region for judging the disk type between the CD and DVD.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an apparatus for judging an optical disk by detecting a phase difference between E and F signals corresponding to two sub-beam signals detected by an optical pick-up apparatus.
In order to achieve the above objects, there is provided an apparatus for judging an optical disk in accordance with a first embodiment of the present invention which includes an optical type pick-up apparatus for reproducing a data written on an optical disk and outputting a RF signal, a RF amplifier for amplifying the RF signal inputted form the optical type pick-up apparatus to a predetermined level, removing a noise contained in the signal, processing a low pass filtering with respect to the signal, and outputting a predetermined voltage, a first comparator for comparing a voltage corresponding to a first sub-beam inputted from the RF amplifier and a previously set reference voltage and selectively outputting a high level signal or a low level signal in accordance with a result of the comparison, a second comparator for comparing a voltage corresponding to a second sub-beam inputted from the RF amplifier with a previously set reference voltage and selectively outputting a high level signal or a low level signal in accordance with a result of the comparison, a gate circuit for outputting a low level signal when two signals inputted from the first comparator and second comparator are identical and outputting a high level signal when two signals outputted from the same are not identical, a controller for judging the type of a disk mounted in the deck in accordance with an output signal inputted from the gate circuit, and a servo unit for controlling the driving of the optical type pick-up apparatus in accordance with a control signal from the controller.
In order to achieve the above objects, there is provided an apparatus for judging an optical disk in accordance with a second embodiment of the present invention which includes an optical type pick-up apparatus for reproducing a data written on an optical disk and outputting a RF signal, a RF amplifier for amplifying the RF signal inputted form the optical type pick-up apparatus to a predetermined level, removing a noise contained in the signal, processing a low pass filtering with respect to the signal, and outputting a predetermined voltage, a controller for converting two voltages corresponding to two sub-beams inputted from the RF amplifier into a digital signal, comparing the thusly converted digital signal with a previously set reference voltage and judging the type of the disk in accordance with a result of the comparison, and a servo unit for controlling the driving of the optical type pick-up apparatus in accordance with a control signal from the controller.
Additional advantages, objects and other features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims as a result of the experiment compared to the conventional arts.
REFERENCES:
patent: 4759007 (1988-07-01), Eberly
patent: 5574714 (1996-11-01), Masashi et al.
patent: 5666340 (1997-09-01), Macola
patent: 5721718 (1998-02-01), Hwang
patent: 5959955 (1999-09-01), Choi
patent: 5963523 (1999-10-01), Kayama et al.
patent: 5966357 (1999-10-01), Ryoo
Patent Abstracts of Japan, vol. 98, No. 12, for JP 10-334574, patent document published Dec. 18, 1998.
Kim Nark Seog
Oh Sung Min
Samsung Electronics Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Young W. R.
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