Optical disk track counting apparatus and method for improved track access

A track-counting apparatus for an optical disk, comprising:

• an optical detecting head which detects light reflected from an optical disk,
• a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by a binary quantization of said tracking-error signal at a point of zero crossing of said tracking error signal;
• a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk;
• and
• a track counter connected to said second waveform-generating circuit and which counts a number of tracks traversed by a spot beam which strikes a surface of an optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, and wherein said track counter further comprises;
• an edge-detection circuit which detects an edge of said track-crossing signal and generates an edge-crossing signal;
• a logical product circuit which takes a logical product of said edge-crossing signal generated by said edge-detection circuit and said mirror signal, and generates an effective edge signal;
• and
• a counter for counting the number of tracks traversed by said spot beam, in response to said effective edge signal,
• wherein said track counter further comprises a seek direction discriminating circuit which determines a seek direction of said head by judging from a target track and a current track position of said head, and
• wherein said track counter further comprises a direction discriminating circuit connected to said first waveform-generating circuit and said seek direction discriminating circuit and which generates a pulse-discriminating signal from said track-crossing signal in response to an output of said seek direction discriminating circuit.

A method for counting a number of tracks for an optical disk utilizing a track-counting apparatus comprising an optical detecting head which detects light reflected from an optical disk, a first waveform-generating circuit connected to said head and which detects a tracking-error signal showing a skew of a beam spot from a track, from a playback signal output from said head and generates a track-crossing signal by binary quantization of said tracking-error signal, a second waveform-generating circuit connected to said head and which generates, from said playback signal output from said head, a mirror signal that indicates a mirror-surface area between tracks of said optical disk and a track counter connected to said second waveform-generating circuit and which counts the number of tracks traversed by a spot beam which strikes a surface of the optical disk, when it is moved in a radial direction of the optical disk, in response to both said track-crossing signal and said mirror signal, wherein said method comprises the steps;

• generating an edge-crossing signal by detecting an edge of a track-crossing signal;
• generating an effective edge signal by taking the logical product of said edge-crossing signal and said mirror signal;
• separating said effective edge signal into a count-down signal and a count-up signal, in response to information representing a seek-direction of said optical head;
• and
• counting a number of tracks traversed by said head in a radial direction of said optical disk utilizing at least one of said count-down signal and said count-up signal.