Abstract: A bioprocess container consists of a flexible container, placed inside a heat exchanger. By providing a disposable agitation device inside the sealed container, a filled container can be stirred without having to open the container. Possible agitation elements include traditional stirrers, rotating magnetic rods, bladder devices integral with the structure of the container, as well as different devices for manipulating the shape of the sealed container. Finally, a containment disk is used to ensure that the magnetic rod is maintained in the magnetic field.

Abstract: Apparatus for mixing aqueous foam with a slurry of gypsum and water. A cylindrical housing includes, in its upper end, an inlet for a slurry and a helical diverter for directing the slurry in a downward spiral flow path. An inlet for aqueous foam in located in said diverter and directs the foam into the incoming slurry. An annular flow restrictor is located in the lower end of the housing. Turbulence resulting from diversion of the incoming slurry from linear flow to a downward spiral flow path and from changes in spin diameter and speed through the flow restrictor uniformly mix foam with the slurry.

Abstract: A system and associated methods for the fabrication and evaluation of an array of electrode or electrolyte materials for use in a solid oxide fuel cell, the system including a material handling device operable for individually containing a plurality of materials, a mixing device operable for mixing the plurality of materials to form a plurality of combinations of the plurality of materials, and a material delivery device operable for delivering a predetermined one of the plurality of combinations of the plurality of materials to each of a plurality of regions of a substrate, wherein the plurality of regions of the substrate form an array. The system also including a temperature control device operable for heating the array, thereby sintering the array.

Abstract: A more efficient process and method for dispersing gas or other fluids into a liquid which may have solid suspension. More particularly, the process includes maximizing the transfer of oxygen by an impeller by selecting a Froude Number value and/or Surface Power Density value and analyzing these two relative to the desired Standard Aeration Efficiency value desired for the impeller.

Abstract: The invention relates to a mixing apparatus and a method for mixing gas in a closed mixing reactor, which uses gas as a process chemical with a high efficiency and where the content of pulverous solids in the solution is great. The aim is to obtain a flow in the reactor which sucks gas from above the surface of the liquid using rotating mixing devices in the centre of the reactor, and to mix said gas throughout the reactor capacity. The mixing apparatus of the invention comprises at least two mixers located at different heights, and on the same shaft. The upper mixer is equipped with a central plate attached to the shaft, with essentially vertical inner blades rising upwards and downwards and outer vanes directed outwards from the central plate, which are inclined from the horizontal. The lower mixer is equipped with a central plate attached to the shaft with vertical blades located on the outer edge.

Abstract: The invention is a method for performing a stratigraphically-based seed detection in a 3-D seismic data volume. The method incorporates criteria that honor the layered nature of the subsurface so that the resulting seismic objects are stratigraphically reasonable. The method may be used to extract from a seismic data volume all seismic objects that satisfy the input criteria. Alternatively, the method may be used to determine the size and shape of a specific seismic object in a seismic data volume.

Abstract: A speaker comprising: a magnetic circuit provided with a through hole, and a recess formed around the through hole for retaining a magnetic fluid. The speaker further comprises a bearing provided in the through hole and a shaft supported by the bearing to be movable up and down and fixed to a center cap fixed to a voice coil. A gap between the bearing and the shaft is filled with the magnetic fluid. The speaker eliminates a damper, and realizes a very low f0 which has not been obtained before. Furthermore, the magnetic fluid absorbs friction and resonance between the bearing and the shaft, and the magnetic fluid is kept in the recess and is supplied smoothly into the gap between the shaft and the bearing. Thus, generation of abnormal sounds is suppressed and a large amplitude operation is realized in the speakers of the present invention.

Abstract: A time keeping device of an electric timepiece comprising one motor that can rotate in the forward direction and the reverse direction, a branch mechanism, and a plurality of wheel trains that are branched by the branch mechanism, wherein the motor is rotated in the forward direction to drive one wheel train thereby to carry out a mechanical display, and is rotated in the reverse direction to drive the other wheel train thereby to carry out another mechanical display. The time keeping device further comprises a merge mechanism in addition to the branch mechanism, and a plurality of wheel trains that are branched by the branch mechanism and are merged by the merge mechanism. The motor is rotated in the forward direction to drive one wheel train thereby to carry out a mechanical display, and is rotated in the reverse direction to drive the other wheel train thereby to carry out another mechanical display.

Abstract: The invention relates to a timer device capable of performing one or more control actions in response to the time lapsed since a user initiated action took place. The timer device comprises contact means operatable between two conditions, timer means, and means for storing first and second time stamps. The device further comprises control means for setting a first time stamp in response to the contact means being operated between first and second conditions, setting a second time stamp in response to the contact means being operated between the second and first conditions, calculating the time elapsed between the two time stamps, comparing the elapsed time with a preset time value, and performing a control action if the elapsed time is greater than the preset time value.

Abstract: The invention relates to a tourbillon for a watch having a setting device for setting the hands of the watch. The tourbillon has a circular balance wheel (6) that can swivel about a swivel axis. In addition, an escapement is provided that consists of a pallet (8) and of an escape wheel (9), whereby the balance wheel (6) and the escapement are arranged on a base plate (1), and a balance wheel shaft of the balance wheel (6) is rotationally mounted with its one end on the base plate (1) and with the its other end on a cage (5) that surrounds the balance wheel (6) like a basket. The cage (5) comprises, outside of the radially encircling periphery of the balance wheel (6), a number of interspaced pillars (3) fastened to the base plate (1) and forms, with the base plate (1), a rotating mount, which is connected in a fixed manner to the seconds drive of the watch and, with this drive, can be rotationally driven about a rotation axis (7) that is coaxial to the swivel axis.

Abstract: The Electronic Light Clock consists of counting circuits and receives its seconds pulses from crystal oscillator or a quartz.

Abstract: To provide a thin type timepiece having antimagnetic performance and waterproofness. A case side wall includes therein a movement. A case back lid is fixed to the case side wall by raised portions. Further, the case back uses a two-layer clad material of a soft magnetic material and a non-magnetic material, and the soft magnetic material is disposed on the movement side of the case back lid.

Abstract: A device for writing data to a recording medium and a method for fabricating the device is presented. According to one embodiment, the device includes an electrical conductor having a cross-track portion, wherein the cross-track portion includes first and second opposing surfaces, and wherein the cross-track portion defines an aperture extending from the first surface to the second surface. The device also includes a dielectric portion disposed in the aperture such that the dielectric portion defines a ridge waveguide having a lowest-order mode cut-off frequency that is less than the frequency of incident optical energy used to heat the recording medium.

Abstract: An information recording medium comprising an information recording film formed on a base on which regular depressions and projections having Ra of 0.1 to 1.5 nm have been formed, the information recording film containing as a major component a rare earth-transition metal amorphous alloy capable of magnetically reproducing a recorded information.

Abstract: An optical disc drive 1 of the present invention can record and/or reproduce data including audio data and non-audio data onto and/or from a multi-session optical disc 2 when the optical disc is loaded into the optical disc drive.

Abstract: Herein disclosed is an optical disc driving apparatus 100, 200 for driving an optical disc while reading out information contained in the optical disc, the optical disc having an outer peripheral surface, comprising: a housing 101 formed with an loading slot having the optical disc passed therethrough; first detecting means 102 for performing a detection of the outer peripheral surface of the optical disc to be moved into the housing 101; and second detecting means 103 for performing a detection of the outer peripheral surface of the optical disc to be moved into the housing 101 after the detection of the outer peripheral surface of the optical disc is performed by the first detecting means 102; and judging means 104 for judging whether one optical disc or partially overlapped optical discs are passed through the loading slot 101a of the housing 101 based on results detected by the first and second detecting means 102 and 103.

Abstract: Device for storing disc-shaped information carriers and for their subsequent selective manipulation. The disc-shaped information carriers can be placed on carriers arranged in a circle around the manipulator axis of rotation. The design with partially turnable carriers allows for arrangement of the carriers on the axes of partial turning in columns. The manipulator consists at least of two arms. The long arm is equipped with a movable arm and the short arm is equipped with a picker of disc-shaped information carriers. By swinging out of the movable arm against the carrier, the carrier is turned out and the given tray is separated from the others and it can thus be served by the manipulator.

Abstract: A focus search control unit for outputting an order to move an objective lens to the vicinity of a targeted position is provided with a trajectory generating unit for generating a position trajectory to move the objective lens such that the objective lens approaches the targeted position gradually. The position trajectory output from the trajectory generating unit is a position trajectory with which resonance frequency components that the lens moving unit has are removed or attenuated by making smooth the variation of acceleration of the objective lens moved by the lens moving unit. The position trajectory is defined by, for example, a function of third order or higher with respect to time.

Abstract: When an optical disk is tilted in its radial direction, coma aberration may occur to cause a phase shift in a tracking signal, thereby making tracking control less accurate. There are provided an optical head that records information on an optical disk and/or reproduces information written in the optical disk, the optical head comprising an objective lens 4 that condenses light on the optical disk, light receiving means 8 of receiving a reflected beam from the optical disk to obtain a received light signal, tracking error signal detecting means 9 of detecting a tracking error signal in the received light signal, and optical means 6 of attenuating the quantity of light in a central area of a tracking error signal detecting beam of the reflected beam incident on the light receiving means 8, the tracking error signal detecting beam being used to detect the tracking error signal.

Abstract: A defective area on a write-once type optical recording medium, e.g., such as a BD-WO, is effectively managed with a method that can efficiently replace and/or record data that has been recorded in a defective area of the disc, e.g., in a spare area of a data area of the BD-WO. During the reproduction of data, the data that has been recorded and replaced can be read out and reproduced from an area other than a spare area. New TDFL information may be recorded cumulatively with the previous TDFL information as defect management information for the defective area, or repeatedly recorded at least twice in a certain recording region, e.g., a recording region chosen from a lead-in area, the data area, and a lead-out area, so that the temporary defect list information can be accurately and reliably secured.

Abstract: A recording medium of writable once type, and a method and apparatus for managing a defective area on the recording medium are provided. The method includes detecting an existence of a defective area within a data area of the recording medium once data are written onto the data area in a data writing operation; writing data written in the defective area onto a spare area of the data area if the defective area is detected; writing temporary management information pertaining to the defective area, onto a temporary management area on the recording medium; and writing access information for accessing the temporary management information, onto a reserved area on the recording medium.

Abstract: A PLL circuit that optimally generates a clock signal with two reference signals having different frequencies. The PLL circuit includes a VCO for generating the clock signal in accordance with a control voltage. A first loop controls the frequency of the clock signal in accordance with a first reference signal. A second loop controls the phase of the clock signal in accordance with a second reference signal, whose cycle is longer than that of the first reference signal. The second loop supplies the VCO with the control voltage at a constant value until the difference between the frequencies of the first reference and clock signals converges to within a predetermined range. Then, the second loop supplies the VCO with a control voltage at a level corresponding to the difference between the phases of the second reference and clock signals.

Abstract: An optical recording medium for accurately deriving the address information or the disc rotation control information despite narrow track pitch and for recording signals to a high density, and a method and apparatus for recording and/or reproducing such optical recording medium. The optical recording medium has a wobbled groove and pits formed at a pre-set interval in an area between turns of the wobbled groove. The recording/reproducing method includes controlling rotation of the optical recording medium by a wobbled signal from the groove and detecting the position on the optical recording medium of a recording signal by pit signals detected from the pits. The recording/reproducing apparatus includes a detection device for detecting the wobbled signal from the groove and a detection device for detecting pit signals from the pits.

Abstract: An optical disc drive 1 of the present invention includes a spindle motor 11 for rotating the optical disc 2, a spindle driver for driving the spindle motor 11 equipped with rotation number measuring means 232 for measuring the rotation number of the spindle motor 11, brake means for braking the spindle motor 11 to reduce the rotation number thereof, which includes at least three types of brake modes, and selecting means for selecting one of the at least three types of brake modes in response to the rotation number measured by the rotation number measuring means 232 when the rotation number of the spindle motor 11 is to be reduced. The optical disc drive 1 may further includes judging means for judging whether the rotation number of spindle motor 11 measured by the rotation number measuring means 232 reaches a predetermined target rotation number when the rotation of the optical disc 2 is to be stopped by the spindle motor 11.

Abstract: An apparatus automatically controls the laser power of the light source by the feedback output of the APC detector and prevents the increase of laser power due to an abnormality of the APC detector. The automatic power control unit controls the drive amount of the light source by the detection output of the APC detector, which monitors the emission power of the light source, measures the relationship between the APC drive instruction amount and the detection output of the APC detector, and compares this inclination with the inclination at normal time. Also the automatic power control unit compares the error values before and after APC, and detects the change of the quantity of returned light during a predetermined period. As a result, data destruction due to separation, deviation, contamination or deterioration of the APC detector can be prevented effectively.

Abstract: An optical disc drive of the present invention includes a buffer memory 35 for temporarily storing the data received from the host, consecutive recording means which temporarily interrupts recording of the data onto an optical disc 2 in the case where the data transfer from the host cannot keep up with the recording process and the data stored in the buffer memory 35 falls below a predetermined amount, and then consecutively records the remaining data from the end of the recorded data when the buffer memory 35 is filled with data transferred from the host, counting means for counting the number of recording interruptions, and recording-speed adjustment means for adjusting the recording speed for the optical disc in the case where the count number by the counting means is greater than a predetermined value.

Abstract: An optical disc drive 1 of the present invention includes an electrically rewritable flash ROM 32 which stores firmware of the optical disc drive 1; means for judging whether or not the loaded optical disc 2 is a predetermined type of optical disc in which update data for updating the currently stored firmware is stored when the optical disc 2 is loaded into the optical disc drive 1; a buffer memory 31 for temporarily storing the update data recorded in the loaded optical disc 2 in the case where the judging means judges that the loaded optical disc 2 is the predetermined type of optical disc; and control means 9 for determining whether the currently stored firmware of the optical disc drive 1 should be updated with the update data based on the absence or presence of a predetermined signal (a signal outputted when an eject button is pushed), and updating the currently stored firmware with the update data stored in the buffer memory 31 in the case where it is determined that the currently stored firmware of th

Abstract: A method for adjusting a reference level of an analog signal from a plurality of periodically sampled points includes the following steps. Firstly, a first level shift from an preliminary reference level to the last second sampled point within a specified period and a second level shift from the preliminary reference level to the last sampled point within the specified period is determined when one of a first level of the last second sampled point and a second level of the last sampled point is higher than the preliminary reference level and the other is lower than the preliminary reference level. Then, the preliminary reference level is moved toward the first level when an absolute value of the first level shift is greater than an absolute value of the second level shift, and the preliminary reference level is moved toward the second level when the absolute value of the first level shift is less than the absolute value of the second level shift, thereby defining an adjusted reference level.

Abstract: When a code word sequence is generated by converting input data words of p bits into code words of q bits and concatenating adjacent ones of the code words with a merge bit sequence of r bits in order to obtain the best DSV value, according to one aspect, the adjacent code words are concatenated with the merge bit sequence of r bits which is selected, free from the restriction of the minimum run-length of (d+1)T and the maximum run-length of (k+1)T based on the run-length limiting rule RLL(d, k) but permitting the minimum run-length of (d+1)T and the maximum run-length of (k+2)T.

Abstract: The invention relates to a method for generating a primary binary signal having a predetermined spectral shape in a predetermined frequency range, in particular having a notch in the power spectrum in a predetermined frequency range. In order to avoid crosstalk between a primary binary signal and a secondary binary signal it is proposed according to the invention that data-words are modulated into channel-words forming the channel bitstream of the primary binary signal and that the modulation of the data-words is chosen such that the predetermined spectral shape of the channel bitstream of the primary binary signal is achieved by using an evaluation criterion based on a spectral weight function the shape of which is tailored to the spectral extent of the channel bitstream of a secondary binary signal.

Abstract: A deck mechanism for a magnetic recording/reproducing apparatus comprises a main deck provided with a head drum and a capstan motor; a sub-deck installed on the main deck to be loaded/unloaded, the sub-deck being provided with a pair of reel discs, onto which tape reels of a tape cassette are seated; a pole base loading unit for taking out and guiding a tape to be in contact with a side of the head drum when the sub-deck is loaded and guides; a pinch roller unit for compressing the tape against a spindle of the capstan motor when the sub-deck is loaded; a brake unit for selectively braking one of the roll discs; a main sliding member mounted on the main deck to be capable of reciprocatingly sliding, the main sliding member controlling the driving of the pinch roller unit; and a main cam gear mounted on the main deck to be capable of rotating, the main cam gear causing operating all of the sub-deck, the pole base loading unit, the brake unit, and the main sliding member to perform linked movements while the ma

Abstract: A locking mechanism of an external optical disk drive. The locking mechanism of an external optical disk drive with a cover and an upper housing comprises a curved extension portion, a fixing support, a gear mount, a motor, and a switch. The curved extension portion includes two posts and is positioned at the cover. The fixing support is fixed on upper housing and the cover is pivotally coupled to the upper housing. The gear mount is positioned on the upper housing and includes a gear train. The motor is fixed on the gear mount and connected to and driving the gear train. The switch sends command to stop or start the motor when any one of the posts contacts the switch.

Abstract: An optical disk drive assembly. A top housing, cover, tab, solenoid switch base, solenoid switch, hook, and torsion spring work to enable securing and opening of the cover, rotatably connected to the top housing with a front edge. The tab protrudes from the front edge of the cover in the middle, and defines an opening. The solenoid switch base is disposed on the top housing and comprises a torsion spring and a spring support and defines a shaft opening. The solenoid switch is inserted at the solenoid switch base and comprises a pivot and a tension spring disposed on the pivot. The hook comprises a hook shaft, and the hook pivots on the solenoid switch with the hook shaft accommodated in the shaft opening. The torsion spring is disposed at the spring support of the solenoid switch base to open the cover.

Abstract: The present invention relates to a disc ejection device of a disc drive to urgently eject a tray for holding a disc from the housing of the disc drive. The disc ejection device includes a first bar, a second bar, and a first protrusion. The first bar and the second bar are rotatably connected with the tray respectively. One end of the first bar sticks out of the panel of the disc drive, and the other end of the first bar is located touching against one end of the second bar. The second bar has a first latch located touching against the first protrusion which is connected with the housing. A user may move the stick-out end of the first bar to eject the tray.

Abstract: There is provided an information processing apparatus with a display device placed on a front thereof in a transferable manner. In the apparatus, pluralities of openings are formed to allow an information recording medium to pass through each of the openings. The apparatus comprises a display device and a transfer unit. The display device displays an operation state of the information processing apparatus and to be transferable in front of the plurality of openings. The transfer unit is configured to control the display device so that the display device is transferred to a position at which the display device masks, of the plurality of openings, another opening other than a particular opening through which an information recording medium in operation is allowed to pass.

Abstract: A disk drive unit is provided that is capable of reasonably, smoothly opening/closing a shutter by rotation of an inner rotor. The disk drive unit is configured such that an inner rotor (4) is reasonably, smoothly rotated by sequentially engaging a shutter opening/closing starting projection (72), a rack portion (74), and a shutter opening/closing ending projection (76) of a rack member (71) with a shutter opening/closing starting recess (26), a partial gear (27), and a shutter opening/closing ending recess (28) in the outer periphery of the inner rotor (4).

Abstract: Only a pivot arm and a torsion spring are employed to open a shutter of a cartridge. Hence, a structure of a cartridge holder with such a cartridge opening mechanism is much simpler than the prior art. The pivot arm is employed to open the cartridge shutter when the cartridge is inserted into the cartridge holder. The torsion spring provides a restoring force to return the pivot arm back to a closed position when the cartridge is ejected. Adverse effects, which are generated during a rotation of a disc in the prior art cartridge opening mechanism, can be eliminated.

Abstract: A micro-electro-mechanical systems (MEMS) device is presented that can read very high density magnetic media and very high density CD ROMs. Both the magnetic and optical read heads comprise one or more cold cathode MEMS e-beam cells. The e-beams are deflected according to the data bit being interrogated and the state of that bit is determined by a detector. Large arrays of such cells can simultaneously read large areas of the memory media. Arrays of such MEMs detectors can comprise a plurality of “steerable” e-beam emitters that can be directed to interrogate specific data sites on the magnetic media. Thus, in some cases, the media can remain stationary. Densities of 200 gigabits per square inch or more and read speeds greater than 1000 times faster can be achieved.

Abstract: It is an object of the invention to allow the use of a practical light source to record information in each information recording area of a recording medium having a plurality of information recording areas through the use of holography while moving the recording medium.

Abstract: An optical pickup is disposed which irradiates a laser beam onto an optical disc where a guide groove having characteristics of thermal interference (heat discoloration) is spirally formed. The optical pickup irradiates the laser beam along the guide groove to conduct one of data recording in which pits indicating a data length are formed, and visible-image formation in which a part of the optical disc is discolored. The laser beam irradiation position is controlled so that the data recording is conducted with starting from the inner peripheral side of the optical disc, and the visible-image formation is conducted with starting from the outer peripheral side of the optical disc.

Abstract: An optical element comprises: a diffractive structure having a plurality of diffracting ring-shaped zones arranged around an optical axis on at least one optical surface; and an optical path difference giving structure arrranged on an optical surface of at least one of the plurality of diffracting ring-shaped zones, for giving a prescribed optical path difference to a prescribed light beam passing through the diffracting ring-shaped zone, wherein the optical surface of the diffractive structure is a structure having a diffracting function for setting L-th (L≠0) order diffracted light of the light beam having the first wavelength &lgr;1 to a maximum diffraction efficiency and for setting M-th (M≠0) order diffracted light of the light beam having the second wavelength &lgr;2 to a maximum diffraction efficiency in case of an assumption of no existence of the optical path difference giving structure.

Abstract: When the DVD provided with the DVD substrate 2 having thickness t2 of 0.6 mm is installed in the optical disc apparatus, the light beam 4 having wavelength &lgr;1=655 nm is used as luminous flux of numerical aperture NA=0.63 to be condensed on the information surface 2a on the DVD substrate 2. When the CD provided with the CD substrate 3 having thickness t2 of 1.2 mm is installed in the optical disc apparatus, the light beam 5 having wavelength &lgr;2=790 nm is effectively used as luminous flux of approximate numerical aperture NA=0.45 to be condensed on the information surface 3a on the DVD substrate 3. The wavefront aberration caused by a thickness difference between the DVD substrate 2 and CD substrate 3 is canceled out by the chromatic aberration caused by a wavelength difference between the light beams 4 and 5. Therefore, in spite of the difference in the transparent substrates, the light beams are suitably condensed respectively on the information surface 2a and 3a.

Abstract: An optical disk pickup system includes an array of photodiodes 101 for converting photons reflected from an optical disk into a plurality of electrical signals each representing a channel. Driving circuitry 407, 408 drives at least one of the electrical signals as a current across a conductor of a flexible cable 403. A low impedance load 404 converts the electrical signal driven across the conductor as a current into a voltage for further processing.

Abstract: An optical pickup having a blade including a first blade in which an objective lens is mounted and which is made of a reinforced plastics material, and a second blade in which driving coils are mounted and which is made of a magnesium alloy material. Since the first blade has a low thermal conductivity coefficient, the heat generated in the coils is prevented from being transferred to the objective lens, whereas the second blade having a high thermal conductivity coefficient radiates the heat generated by the coils to the outside. Thus, the heat distortion of the objective lens can be suppressed, and damages to the coils or rigidity reduction of the blade can be avoided.

Abstract: A lens position determination apparatus of an optical pickup includes a lens holder with a mounted lens, a base supporting the lens holder, and a pressing member. The base has an accommodation surface accommodating the lens holder and a pair of facing support walls on the accommodation surface. The pressing member is a bendable arm. A first elastic portion between arm end portions applies an elastic force in a direction in which the arm end portions closely contact the support walls. A second elastic portion connected to the arm presses the lens holder toward the accommodation surface to fix the lens holder position. The lens adjustment can be performed while the pressing force to fix the lens holder to the base is removed by bending the pressing member into a V shape to reduce frictional resistance of the lens holder with the base during the adjustment.

Abstract: Brackets 9, 9 for supporting respective opposite ends of a guide rod 4 are provided with respective cam faces 95, 95 approximately symmetric about an approximate longitudinal midportion C of the guide rod 4, and at least one of the brackets 9 is provided with an adjusting member for moving the guide rod 4 longitudinally thereof. The cam faces 9 guide the guide rod 4 toward a direction in which the guide rod 4 pivotally moves about the approximate longitudinal midportion C, as the guide rod 4 is moved longitudinally thereof by the adjusting member.

Abstract: This invention provides an optical disk effective in both precision and productivity, and to a process for the manufacture thereof. The optical disk allows reading of the information recorded on each information-recording surface of the two or more information-recording surfaces by varying the focal position of a playback laser beam incident on and passing through said light transmitting substrate; and the optical disk is provided with a transparent layer that is laminated onto the light transmitting substrate and is constituted of a thermoplastic resin sheet of uniform thickness and the transparent layer has an information-recording surface other than the surface of said light transmitting substrate formed thereon.

Abstract: An optical disc has spatial features (notches, bumps, etc.) that intentionally distort the analog Read Data signal. For a mark or space that is centered on a spatial feature, the distortion does not affect the resulting binary Read Data signal. If an edge of a mark or space is near the spatial feature, the resulting binary Read Data signal is altered. For calibration, marks or spaces are written adjacent to spatial features, with a range of times for initiating the writes. The result is a range of write times that do not alter the binary Read Data signal. From these known times and spatial locations, it is known when a mark or space must be written to ensure accurate spatial placement.

Abstract: Preformatted areas in at least the most distal recording layer from an object lens among a plurality of recording layers in an optical disc include guard areas at both ends of the respective recording layer in the tracing direction. No data is recorded on the guard areas.

Abstract: A phase change type information storage medium is provided, which achieves high-speed recording/reproduction. A DVD-RW disc having a substrate formed with grooves, lands, and land pre-pits, on which are laminated a first dielectric layer, a phase-change recording layer, a second dielectric layer, a reflective layer, and an overcoat layer. The disc is rotated at a 3.49-7.0 m/sec linear speed while being irradiated with a laser beam of 600-700 nm wavelength focused by an objective lens of 0.55-0.7 numerical aperture to the phase-change recording layer from the substrate side. The phase-change recording layer is made of a Ge-In-Sb-Te material, and the reflective layer is made of an Ag-Nd-Cu material. The first dielectric layer has a 65-85 nm thickness, the phase-change recording layer has a 10-20 nm thickness, the second dielectric layer has a 13-23 nm thickness, and the reflective layer has a 100-225 nm thickness.