Abstract: According to the present invention, an optical inspection apparatus which can observe a light-transmitted portion and a light-reflected portion within objects of inspection, distinguishable from each other within the same field of vision, is provided.

Abstract: The invention is an optical system cleaner for an optical disk drive in which a cleaning member is attached directly to a shutter or a member corresponding to the shutter to eliminate the need for a mechanism for linking the cleaning member with the shutter. An optical disk drive according to the present invention includes an actuator for projecting an optical beam through an optical system and to a desired position on an optical disk loaded at a reproduction position. The optical disk drive also includes a shutter opening means for opening the shutter of a cassette with a built-in optical disk. The body of the optical system cleaner has a substantially similar shape to said cassette and a moving member attached to the body of said optical system cleaner so as to move freely and driven by said shutter opening means. A cleaning member is attached to said moving member for sweeping out said optical system by merely taking the body of said optical system cleaner in or out of said optical disk drive.

Abstract: In this invention, a driving circuit for moving a head in the radial direction on the recording surface of a disk is coupled to a velocity detecting circuit for detecting the velocity at which the head moves. A velocity profile is provided for storing information on the target velocity of the head. A driving signal generating circuit is coupled to the velocity profile and the velocity detecting circuit for comparing a signal from the velocity detecting circuit with a signal from the velocity profile. The driving signal generating circuit outputs a driving signal to the driving circuit based on the result of the comparison. A controller is coupled to the driving circuit for measuring a time required for moving the head a predetermined distance at a predetermined reference value, and modifying the driving signal based on the result of the comparison. Scatter in feedback quantities or fluctuation in the driving signal during velocity control is thereby corrected.

Abstract: A method and apparatus for initializing disk drive apparatus wherein a pickup head is positioned near the mid-range of tracks on a disk by moving the head at power-on to an innermost track and thereafter moving the head outwardly. As outward movement begins, a tracking error signal is sensed to indicate a track crossing, and the number of tracks crossed are counted until the head is at the mid-range of tracks. A velocity profile is used to speed movement of the head to its destination.

Abstract: The invention calculates the number of track crossing signals to be counted until a target position is reached without an actual seek operation, thus making it possible to complete a seek operation in a short time and without the need of the additional seek operation disclosed in the related art. A memory means is provided for storing the relation between the number of tracks (Delta t) from a current position to a target position and an indicator of the movement of said optical head toward said target position. A control means is provided for calculating the number of track crossing signals to be counted during a seek operation based on said stored relation when the target position is given, and for generating a control signal causing said optical head to seek based on the number of the calculated track crossing signals.

Abstract: The present invention locates spare sectors for replacing secondary defects found during disk use. A sorted defective sector list is maintained for tracking the spare sectors that have been previously used for replacements of other secondary defects. When a secondary defect address is found, a secondary defect list is updated both on the disk and in the drive's memory. A spare sector, for replacing the secondary defect is located by first calculating a group number to determine which group the secondary defect is located in. Next, the boundaries for a plurality of spare sectors allocated for that group is determined. After searching the replacement sector list, the first available spare sector of the plurality of spare sectors is identified as the replacement sector. If all of the plurality of spare sectors have been previously assigned as replacement sectors, a spare sector is instead located from a plurality of spare sectors allocated to a neighboring group.

Abstract: A memory fault mapping apparatus detects faults generated in a memory array during on-line operation. As the memory array is randomly accessed, single bit error are detected, corrected, and mapped into an error memory. The errors may be mapped in an error memory having a memory location for each memory of the memory array or alternatively, by grouping memories together and when the errors generated by any one group exceeds a predetermined threshold of errors, testing only the memories in that group off-line. By grouping the memories a substantial reduction in the amount of error memory required can be achieved. A SEC/DED syndrome generator detects single and double bit errors, correcting the single bit errors while providing an indication of which memory generated the error. An error memory stores error counts for the memory array, each error count indicating the number of errors for a specific memory or a group of memories.