Abstract: In an optical disk recorder, during the sensing of closely-spaced, position-indicating, machine-sensible indicia, a first peak of a track error signal is detected. In response to the first peak being detected, a half-track counter is decremented from a value which depends upon the position of the destination track relative to a current track. In response to the occurrence of a selected value of the half-track counter and the presence of a zero crossing of the tracking error signal, a first timer is activated to mask any defects occurring during the selected first half cycle of the last cycle of the tracking error signal. The half-track counter is again decremented in response to a second peak being detected and the occurrence of a next-to-last zero crossing of the tracking error signal and a second timer is then activated to mask any subsequent defects occurring during the second half cycle of the tracking error signal.

Abstract: A relative position error signal is calibrated in an optical storage device in which a tracking error signal (TES) varies as the light beam shifts its position through the objective lens. The calibration is performed by moving the coarse carriage to a predetermined region of the optical disk and measuring the TES. The fine actuator is adjusted until the tracking error signal equals a predetermined value. Then, the relative position error signal is read and an adjustment to the RPE gain is calculated to bring the gain to a predetermined value. The adjusted gain is used during normal disk access operations.

Abstract: A rotary positioner is rotatably mounted upon a reciprocating carriage of a optical disk drive. To detect and indicate one of a plurality of possible orientations of the disk drive, a side bias force is applied to the rotary positioner in a direction orthogonal to the radius of the disk drive. It has been found that each orientation has a side bias at which gravity effects are removed from the rotary positioner. At these points of gravity accommodation, certain instabilities in servo operation occur. Since each orientation requires a different side bias force to create the respective servo instabilities, the side bias force causing such instability indicates the drive orientation. Two modes of testing for orientation are disclosed. The carriage positioner is actuate for causing a momentary uncorrected radial movement of the carriage. The response of the carriage servo is measured in one of two ways.

Abstract: A single loop servo is used for positioning a lens holding element with respect to an optical disk. The dynamic range of the error signal used in the positioning is dynamically frequency shifted such that the servo summing of the error signal with a reference signal (velocity reference) is always performed within the same dynamic range. This action simplifies circuit operation as the dynamic range of the error signal is compressed at high speeds. Two embodiments of the invention are described.

Abstract: The focus acquire system on optical disk recorder as well as other optical systems, signal processes a focus error signal FES to produce a modified FES which has a peak amplitude occurring closer to a desired focus position than the occurrence of peak amplitude of the FES. The modified FES also is signal processed to sharpen or slim the peak portion such that increasing the amplitude of the modified FES reaches an amplitude detection threshold closer to the true peak of the modified FES, and hence closer to the desired focus position than if the amplitude detection threshold were used on the FES. In a preferred form of the invention, FES is differentiated to produce a differentiated FES, then the differentiated FES is subtracted from FES to produce the modified FES.

Abstract: An optical disk recorder has a fine actuator which holds an objective lens and which is movably mounted on a head carriage. Servo systems connected to the head carriage and the fine actuator cause the fine actuator to seek and track follow based upon signal recovered from a disk while the head carriage is caused to follow the motions of the fine actuator. A tracking error signal is generated indicating the relationship of the beam supplied through the objective lens with respect to tracks on the record medium. An RPE signal (relative position error) is generated by an RPE detector which indicates the relationship of the relative motion of the fine actuator to the head carriage. Both the RPE and TES are calibrated as to offset and as to gain for providing a more precise servo positioning system.

Abstract: A focus acquisition system includes providing a focus offset and changing the offset symmetrically for each measurement cycle. The amplitudes of the readback or tracking error signal are sensed and compared. When the amplitudes of the tracking error or readback signal is different at each of the offsets, then a new measurment cycle is performed after calculating a new offset value. The process is repeated until the temporary measurement offsets result in readback amplitudes that are substantially equal. A best focus is then indicated as being a position in which small defocussing will not substantially degrade the quality of the readback signal.

Abstract: A servo positioning system, such as used in an optical disk or other types of disk drives includes focus and positioning servo circuits. When a focus error is detected, then it is desired to stop the operation of the positioning system. Similarly, when a positioning error is detected, such as excessive speed or a non-zero velocity at the end of a seek or positioning motion, the head carriage should also be stopped. The stopping of the head carriage is by dynamic braking through use of a power amplifier which is switched from a transconductance mode used during normal servo positioning operations to a voltage amplifying mode which is set to a zero input for dynamically braking the servo positioning system to a safe speed and thence to a stop condition whereupon further error recovery procedures may be employed.

Abstract: An optical disk recorder includes disk reflectance calibration means for measuring variations in disk reflectance over the recording area of the disk. Correction factors based on measured reflectance for adjusting sensed signal level and gain reduce the effects of varying reflectance on the sensed signal. In a preferred embodiment, the sensed signal is employed as a signal in quadrature to a tracking error signal for ensuring reliable track counting in a track seeking operation. In a grooved medium, reflectance is calibrated for both grooves and mesas between the grooves.

Abstract: An optical disk recorder is capable of operating with diverse types of optical media. A device initialization procedure is repeated for each receipt of each optical medium. Such procedure includes moving an objective lens to an extreme radial position, defocussing the lens at a most remote position, then calibrating the laser circuits to ensure that the emission of radiation from the laser will not inadvertently destroy signals recorded on the just received medium. Then the medium type is read from the medium and based upon the type indication, various additional calibrating procedures are followed and different sources of laser control values are used for signal exchanging operations between the recorder and received optical medium.

Abstract: This disclosure deals with an optical disk recorder/player (drive) of the type that receives a removable disk for signal exchanging operations. Once a disk is inserted into the drive, the rotation of the disk begins a period of accelerating rotational speed called spin up. During spin up, the focus and tracking systems of the drive are calibrated. Once the disks reach a desired operating rotational speed, a menu is provided for determining when to calibrate a laser in the drive for recording operations. Such writing or recording calibration of the laser occurs at different times in accordance with the types of signal processing functions to be performed with respect to the particular disk. Description includes a media library in which a plurality of optical disk drives are controlled in a manner for minimizing access times to any optical disk within the media library.

Abstract: The focus acquisition system on optical disk recorder as well as other optical systems, uses repeated pulse position pulses with interlead coasting of an objective lens for providing a soft focus acquire. The pulse energization of the lens to move toward an in-focus condition overcomes stiction and friction. While the coasting allows the energy level applied to the lens movement to be minimal, i.e. soft, the purpose of the interdirectional pulse control actuation is to overcome friction without requiring large power to the lens which can cause an overshoot of the lens at the in-focus position. Compensation techniques and stopping the lens at the in-focus position are also shown.

Abstract: An optical disk recorder, or other apparatus, use a rotary actuator for supporting a work tool, such as an objective lens which is pivotable or rotatable without a pivot pin. Rotation causing or tracking coils on the rotary actuator are disposed adjacent to permanent magnets to selectively effect rotation of the rotary actuator about the pivot pin. A bias electrical current is supplied to these coils to generate magnetic fields which are in opposite rotational senses; such fields force the rotary actuator against the pin in such a manner that the point of contact between the rotary actuator and the pin follows the rotation of the actuator about the pin.

Abstract: A position servo system has a position loop and a velocity loop. The position loop controls the stop-lock condition and provides for movement control within a range about the stop-lock position. The velocity circuit is employed for movements outside of the range of the position servo circuit. When the velocity servo's loop is being used, a compare circuit compares the servo drive signal from the velocity circuit with a signal generated by the position servo loop which is tracking the velocity servo loop. When the compare circuit finds that the servo drive signals have equal amplitudes, then the velocity servo loop is disconnected from an actuator with the position servo loop then connected to the activation for completing the movement to a desired or target stop-lock position. The above-indicated servo system controls a topping or fine actuator carried on a carriage moved by a coarse actuator.

Abstract: In a "piggy-back" head support system, a fine actuator which carries the head (lens or transducer) is controlled to move the head. A coarse actuator or headarm movably supports the fine actuator and is mounted on a frame for movement radially of the signal storage disk. The head scans tracks on the disk. A servo actuates the coarse actuator to follow the movements of the fine actuator. In a seek, the fine coarse actuator may not be able to follow the fine actuator resulting in the fine actuator hitting a safety stop. When this happens, seek errors occur. According to the invention, the relative displacement of the fine actuator with respect to the coarse actuator is limited during predetermined portions of a seek operation, i.e., the high speed accelerate and decelerate portions.

Abstract: In a disk recorder, unintended radial portions of a transducer or head, herein termed "skating", is rapidly controlled and stopped before the transducer or head can hit a crash stop. Even when a braking operation is effected in the wrong direction, the skating compensation reverses the braking operation for rapidly stopping the radial motion of a transducer. A pair of clamp circuits are electrically interposed between the servo actuator drive signal generation and a run-out compensation circuit such that the clamping operation does not alter the run-out compensation. The sequences of machine states for effecting the state accommodation are described.

Abstract: A track-seeking apparatus of a disk recorder employs a track-crossing sensor to produce track-crossing signals. An oscillator is slaved to the sensor for supplying substitute track-crossing pulses in the absence of the sensor providing such pulses or when the radial velocity exceeds a threshold velocity. A velocity profile means alters the oscillator frequency so that the oscillator produces track-crossing pulses in accordance with the profile.

Abstract: A focus acquire circuit for use in optical systems, such as optical data recorders and players, uses up to three parameters signals to indicate an in-focus condition. The zero crossing of a focus error signal is combined with a signal indicating that the focus error signal has approached a peak value and with a signal indicating a change in laser drive signal amplitude to indicate an in-focus condition. Various circuit details are illustrated showing how the three parameters cna be combined together for indicating an in-focus condition.

Abstract: An optical disk recorder includes a position servo control loop for causing a beam of radiation to faithfully follow a track on the disk, jump from a current track to an adjacent track or to a small number of tracks away from the current track. Operation of the position servo loop is altered by selectively reversing the phase of a differentiated position error signal and integrating the differentiated position error signal for comparison with a sawtooth signal for moving the beam of radiation from the current track to an immediately adjacent track under continuous position servo control. Upon reaching the adjacent track, the sawtooth signal returns to a reference potential for initiating track following. The servo error between the integrated differentiated position error signal and the sawtooth signal is sufficiently small such that relaxation of the sawtooth signal does not cause any significant perturbations in the positioning servo loop operation.

Abstract: Winding apparatus for continuously winding tape media upon reels contained within closed cartridges. The winding apparatus includes means for supplying cartridges alternatively to three separate in-line winding channels all of which perform a winding function and then collecting the wound cartridges off the individual lines and presenting an output station for a subsequent packing operation. Each channel includes vacuum extension means for reaching through an opening in each cartridge to apply an adhesive patch to the hub of the reel contained within the cartridge. Each line also includes means for continuously supplying tape media to a wind station for winding upon the reels passing through that line. At the wind station, additional vacuum means bring the leading edge of the media into the cartridge and press it against the adhesive patch, thereby attaching the media to the reel.