1. An arc type blade transfer apparatus for transferring an arc type blade having an inner radius and an outer radius, transferring distances of which are different from each other, the apparatus comprising:
a main body which is formed with a space through which the arc type blade passes; and
a transfer roller which is rotatably mounted to the main body and is rotated to transfer the arc type blade, the transfer roller being formed in a truncated-conical shape including a small-diameter end, a large-diameter end and a tapered peripheral surface formed between the small-diameter end and the large-diameter end, and being slantedly mounted with respect to a surface of the arc type blade so that the tapered peripheral surface of the transfer roller is in parallel contact with the surface of the arc type blade.
2. The apparatus according to claim 1, wherein a ratio of a circumferential length of the inner radius of the arc type blade to a circumferential length at a small-diameter contact point of the transfer roller with an inner peripheral portion of the arc type blade is equal to a ratio of a circumferential length of the outer radius of the arc type blade to a circumferential length at a large-diameter contact point of the transfer roller with an outer peripheral portion of the arc type blade.
3. The apparatus according to claim 1, wherein the main body further includes guide members for supporting and guiding the arc type blade to be transferred.
4. The apparatus according to claim 1, wherein the main body further includes a pressure roller which is rotatably mounted to the main body on an opposite side of the arc type blade to the transfer roller and pressurizes the arc type blade toward the transfer roller.
5. The apparatus according to claim 4, wherein the pressure roller is rotatably mounted to an adjusting part which is updown movably coupled to the main body above the pressure roller.
6. The apparatus according to claim 1, further comprising:
a driving unit which is connected to a rotating shaft of the transfer roller to rotate the transfer roller which is slantedly mounted.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. An optical disc having a digital carrier signal written therein, the disc comprising:
a contiguous user data portion comprising a set of user data samples which, when accessed by a readback system, generates a human detectable output, the user data samples stored in a sequence of user data fields of the contiguous user data portion;
a null zone adjacent the contiguous user data portion comprising a sequence of user data fields storing a set of user data samples which, when accessed by a readback system, generates an output with a specified signal to noise ratio so as to be substantially undetectable by a human, wherein hidden data are written to at least selected ones of the user data fields of the null zone to convey a specified informational message related to the optical disc, the specified informational message undetectable by a human when the null zone is accessed by the readback system.
2. The optical disc of claim 1 where the specified informational message is used for forensic tracking to identify whether the disc is an authorized copy.
3. The optical disc of claim 1 wherein the specified informational message comprises a begin synchronization pattern followed by hidden message data, wherein detection of the begin synchronization pattern facilitates subsequent decoding of the hidden message data.
4. The optical disc of claim 2 wherein the specified informational message comprises an audio signal at a frequency above 20,000 Hertz.
5. The optical disc of claim 1 wherein the specified informational message comprises copy protection information encoded with the hidden message, wherein the copy protection information is accessed and verified before access is granted to remaining portions of the disc.
6. The optical disc of claim 1 wherein the null zone is a lead-in zone at beginning portions of the disc.
7. The optical disc of claim 1 wherein the null zone is a lead-out zone at ending portions of the disc.
8. The optical disc of claim 1 wherein the contiguous user data portion comprises a first audio selection, wherein the optical disc comprises a second audio selection, and wherein the null zone is disposed between the first and second audio selections.