Memory disk and apparatus for recording information on memory disk

An optical memory for storing information, in response to light from a head device irradiating said optical memory, by a pit having different optical characteristics from a portion without information on said optical memory, the optical memory having first and second predetermined radii defined from a center thereof and said second predetermined radius being greater than said first predetermined radius, said optical memory comprising:

• a first recording area, located between the first predetermined radius and the second predetermined radius on said optical memory, for storing information such that a spacing between adjacent pits is constant;
• a second recording area, located outside the second predetermined radius, for storing information such that the spacing between adjacent pits increases with increasing radial position as the position at which the pit is made is further removed from the center of said optical memory;
• and
• a predetermined substitute area for storing information corresponding to a defective memory portion located in said first or second recording areas.

A method of recording information to an optical memory which records information in response to light emitted from a head means for recording information on the optical memory which is rotated at a predetermined constant speed during the recording operation, the recording method comprising the steps of:

• detecting a radial position of the head means facing the optical memory;
• controlling the head means to record information in a first format when the radial position of the head means detected by said detecting step is in a first inner area on the optical memory and recording information in a second format when the radial position of the head means detected by said detecting step is in a second outer area on the optical memory;
• detecting a defective memory portion on the optical memory;
• and
• recording information to be recorded in the defective memory portion detected by said defect detecting step on the optical memory in a substitute area on the optical memory.

A method of recording information to and reproducing information from an optical memory, the optical memory recording information in response to light emitted from a head means facing the optical memory for recording information on the optical memory, the optical memory being rotated at a predetermined constant speed during the recording operation, the method comprising the steps of:

• detecting the radial position of the head means facing the optical memory;
• controlling the head means to record information in a first format when the radial position of the head means detected by said detecting step is in a first inner area on the optical memory and recording information in a second format when the radial position of the head means detected by said detecting step is in a second outer area on the optical memory, wherein the step of controlling said head means includes the step of generating clock signals and controlling said head means in response thereto,
• detecting a defective memory portion on the optical memory;
• and
• recording information to be recorded in the defective memory portion detected by said defect detecting step on the optical memory in a substitute area on the optical memory;
• subsequently reproducing information recorded on said optical memory wherein the differences in frequency of the clock signals generated by said clock generating step are within a predetermined range of values at which information may be reproduced by said reproducing step.

An apparatus for recording information on an optical memory having first and second predetermined radii defined from a center of the optical memory, the second predetermined radius being greater than the first predetermined radius, said apparatus comprising:

• motor means for rotating the optical memory at a predetermined constant speed;
• head means facing said optical memory for recording information on the optical memory rotated at said predetermined constant speed by said motor means;
• position detecting means for detecting a radial position of said head means facing the optical memory;
• first head control means for controlling said head means such that a spacing between adjacent pits is constant;
• second head control means for controlling said head means such that the spacing between adjacent pits increases with increasing radial position as the position at which the pits are made is further removed from the center of the optical memory;
• defect detecting means for detecting a defective memory portion on the optical memory;
• substitute means for recording information to be recorded on the defective memory portion detected by said defect detecting means in a predetermined substitute recording area on the optical memory;
• and
• means responsive to the position detecting means for selecting said first or second head control means such that said head means records information in response to said first head control means when the radial position of said head means as detected by said position detecting means is between said first and second predetermined radii, and said head means records information in response to said second head control means when the radial position of said head means as detected by said position detecting means is greater than said second predetermined radius from the center of the optical memory.

A method for recording information on an optical memory, the optical memory recording information in response to light emitted from head means for recording information on the optical memory, the optical memory further being rotated at a predetermined constant speed during the recording process, said head means being selectively controlled by one of two control means, the first control means controlling said head means to record information in a first format in which a spacing between adjacent pits is constant, and a second control means controlling said head means to record information in a second format in which the spacing between adjacent pits increases with increasing radial position as the position of said head means is further removed from the center of the optical memory, the recording method comprising the steps of:

• detecting the radial position of the head means facing the optical memory;
• controlling the head means to record information in a first format when the radial position of the head means detected by said detecting step is in a first area on the optical memory and recording information in a second format when the radial position of the head means detected by said detecting step is in a second area on the optical memory, said second area being located outside the first area on the optical memory;
• detecting a defective memory portion on the optical memory;
• and
• recording information to be recorded in the defective memory portion detected by said defect detecting step on the optical memory in a substitute area on the optical memory.