Disk cartridge

A disk cartridge for accommodating a disk having a main recording surface on one side thereof and a protective surface on an opposite side thereof with the disk cartridge being insertable at a cartridge insertion end thereof into a disk unit which writes information signals to and/or reads information signals from the main recording surface of the disk and includes an objective lens assembly for converging a laser beam on the main recording surface of the disk and a magnetic field application head for applying an external magnetic field to the disk, the disk cartridge comprising a housing including an upper half and a lower half in opposed relation with the disk being rotatably accommodated between said upper and lower halves, said upper half having a first opening for exposing the protective layer to the magnetic field application head and said lower half having a second opening for exposing the main recording surface to the objective lens assembly when the disk cartridge is inserted into the disk unit, said first and second openings being of a defined width measured in a lateral direction of the cartridge at the cartridge insertion end and respectively having first and second pairs of opposed side edges, said upper and lower halves further having respective first and second bridge portions at the cartridge insertion end which are formed of cut-out concavities only surrounding respectively said first and second openings and which interconnect respectively said first and second pair of opposed side edges and wherein the defined width of one of said first and second openings is smaller than the defined width of the other of said first and second openings, and a thickness of a first base member of one of said first and second bridge portions is greater than the thickness of a second base member of the other of said first and second bridge portions.

A disk cartridge for accommodating a disk having a main recording surface on one side thereof and a protective surface on an opposite side thereof with the disk cartridge being insertable at a cartridge insertion end thereof into a disk unit which writes information signals to and/or reads information signals from the main recording surface of the disk, the disk cartridge comprising first and second openings provided on opposing halves of the cartridge at the cartridge insertion end thereof which are each of a defined width measured in the lateral direction of the cartridge and each has a respective first and second pair of side edges, said first and second openings respectively exposing said protective layer and said main recording surface when the cartridge is inserted into the disk unit and wherein the defined width of one of said first and second openings is smaller than the defined width of the other of said first and second openings, said opposing halves further having respective first and second bridge portions at the cartridge insertion end wherein said first and second bridge portions are formed of cut-out concavities only surrounding respectively said first and second openings and which interconnect respectively said first and second pair of opposed side edges and wherein a thickness of a first base member of one of said first and second bridge portions is greater than the thickness of a second base member of the other of said first and second bridge portions.

A disk cartridge for accommodating a disk having a main recording surface on one side thereof and a protective surface on an opposite side thereof with the disk cartridge being insertable at a cartridge insertion and thereof into a disk unit which writes information signals to and/or reads information signals from the main recording surface of the disk and includes an objective lens assembly for converging a laser beam on the main recording surface of the disk and a magnetic field application head for applying an external magnetic field to the disk, the disk cartridge comprising a housing including an upper half and a lower half in opposed relation with the disk being rotatably accommodated between said upper and lower halves, said upper half having a first opening for exposing the protective layer to the magnetic field application head and said lower half having a second opening for exposing the main recording surface to the objective lens assembly when the disk cartridge is inserted into the disk unit, said first and second openings further including respective first and second pairs of opposed side edges, said upper and lower halves further having respective first and second bridge portions at the cartridge insertion end which are formed of cut-out concavities only surrounding respectively said first and second openings and which interconnect respectively said first and second pairs of opposed side edges wherein a first thickness dimension of a thin-walled portion of one of said first and second bridge portions is greater than the first thickness dimension of a thin-walled portion of the other of said first and second bridge portions, measured in the lateral direction of the cartridge, and a second thickness dimension of a first base member of one of said first and second bridge portions is greater than the second thickness dimension of a second base member of said first and second bridge portions.