Minidisc Related Patents

Eric Woudenberg
July 2001


The Minidisc related patents that follow were found by searching public domain patent documents available from the US Patent and Trademark Office website for keywords such as ATRAC and Minidisc. They represent a wealth of information for those wishing to dig into Minidisc's roots and evolution.

The patents are interesting for several reasons. Foremost, they describe each invention's prior art and background. In that description are meaty details of the Minidisc system, covering such topics as the ATRAC compression system, laser optics, servo control, and the MD's logical data layout. The patents are also interesting because, through them, one can track the improvements that have been made to Minidisc technology over the years. There are patents covering battery power conservation, ATRAC enhancements (including the advent of ATRAC2), mechanism and drive refinements, etc. Finally, the patents provide a means of tracing the historical evolution of Minidisc technology. They show Minidisc's derivation from the audio CD (and the subsequent, but never productized, CD-MO [Magneto-Optical]) as well as intriguing glimpses of paths the designers pursued during development (e.g. the specification of CD-I's "B" mode audio [37.8 khz sampling, ADPCM @ 4 bits/sample] for the format in US05224087 until (I suspect) their tentative collaboration with Philips exposed them to the wisdom of perceptual coding).

As for how to read the patents, I can only recommend a dogged, methodical approach. It is odd that these documents, intended to explain a practice precisely, end up being pedantic and verbose to the point of near unreadability! I am not sure what the patent lawyers have in mind, but perhaps it is felt that this style of English is so bad already that it cannot really be threatened by the passage of time. Whatever its purpose, the language in these documents makes skimming to get the gist of them difficult. I found the most informative sections the Background of the Invention and the subsequent Summary of the Invention. If you have the stamina (I didn't), try slogging through the Detailed Description of the Preferred Embodiment. This will tell you in nitty-gritty detail what, in particular, is being disclosed.

I have heard that a patent filing typically runs about US$50,000. Perhaps we can think of these documents then, with their obscure and redundant language, as the Sutras of our technological age. Assembled at great cost, impenetrable to the uninitiated, they hold the hard won secrets of the world's technical priesthood. May you read, digest, and be nourished.

Patent summaries, organized by topic

To make browsing easier I have attempted to group patents by topic and briefly summarize them. In some cases I give only a cursory summary because I do not understand precisely what, beyond the prior art, is being disclosed. There are other cases where my description may be superficial or incorrect. I am indebted to any readers willing to go deeper than I have who can offer improved summaries. Simply email them and I will update the page.


US05244705Disc-shaped recording medium
abstract fullSony CorporationAssign./Filed: Sept. 14, 1993/ Aug. 19, 1991
First proper MiniDisc patent (chronologically); covers recording of compressed audio on an enclosed disc. Borrows heavily from US05243588.

US05309421Recording and/or reproducing apparatus for optical disk
abstract fullSony CorporationAssign./Filed: May 3, 1994/ Aug. 14, 1991
General Minidisc - shows MZ-1-ish prototype.

US05552896Disk recording/reproducing apparatus and disks applied therein
abstract fullSony CorporationAssign./Filed: Sept. 3, 1996/ Nov. 18, 1993
Covers most components of the Minidisc system (general MD patent?).


US05301205Apparatus and method for data compression using signal-weighted quantizing bit allocation
abstract fullSony CorporationAssign./Filed: April 5, 1994/ Jan. 29, 1993
ATRAC - includes detailed discussion of ATRAC's bit allocation method.

US05381143Digital signal coding/decoding apparatus, digital signal coding apparatus, and digital signal decoding apparatus
abstract fullSony CorporationAssign./Filed: Jan. 10, 1995/ Sept. 8, 1993
Enhancement to ATRAC. Detailed description of ATRAC's Block Floating operations. Some commonality with US05301205.

US05388209Apparatus for high-speed recording compressed digital data with increased compression
abstract fullSony CorporationAssign./Filed: Feb. 7, 1995/ July 31, 1992
Method of stripping out redundant information in ATRAC for further compression into a variable bit rate stream (for recording to a high cost storage device e.g. IC card memory).

US05394473Adaptive-block-length, adaptive-transforn, and adaptive-window transform coder, decoder, and encoder/decoder for high-quality audio
abstract fullDolby Laboratories Licensing CorporationAssign./Filed: Feb. 28, 1995/ Dec. 11, 1991
Transform audio coding with adaptive block length, transform and window. This patent (at least) must cover some of the IP embodied in Minidisc's ATRAC. Description has commonality with other Dolby patents.

US05454011Apparatus and method for orthogonally transforming a digital information signal with scale down to prevent processing overflow
abstract fullSony CorporationAssign./Filed: Sept. 26, 1995/ Nov. 23, 1993
ATRAC enhancement. Strong similarity to US05381143.

US05461378Digital signal decoding apparatus
abstract fullSony CorporationAssign./Filed: Oct. 24, 1995/ Sept. 8, 1993
ATRAC decoding enhancement. Similarity to US05381143.

US05471558Data compression method and apparatus in which quantizing bits are allocated to a block in a present frame in response to the block in a past frame
abstract fullSony CorporationAssign./Filed: Nov. 28, 1995/ Sept. 29, 1992
ATRAC enhancement? Good discussion of Pre-echo. Does not share simlarity with other ATRAC patents.

US05490170Coding apparatus for digital signal
abstract fullSony CorporationAssign./Filed: Feb. 6, 1996/ Nov. 30, 1993
Block floating enhancement. Similarity to other ATRAC patents.

US05734792Enhancement method for a coarse quantizer in the ATRAC
abstract fullMatsushita Electric Industrial Co., Ltd.Assign./Filed: March 31, 1998/ Dec. 6, 1993
Improvement to ATRAC encoder to reduce quantization noise.

US05819211Adaptive transform acoustic coding circuit formed in a single application specific integrated circuit of a mini disk system
abstract fullSamsung Electronics Co., Ltd.Assign./Filed: Oct. 6, 1998/ Feb. 26, 1996
Integrated circuit for decoding ATRAC. Gives explicit timings and RAM requirements for the ATRAC decoding operation.

US05825320Gain control method for audio encoding device
abstract fullSony CorporationAssign./Filed: Oct. 20, 1998/ March 13, 1997
Gain control method for handling pre-echo used by ATRAC2/3.

US05960390Coding method for using multi channel audio signals
abstract fullSony CorporationAssign./Filed: Sept. 28, 1999/ Oct. 2, 1996
ATRAC2/3 Gain Control.

US05974379Methods and apparatus for gain controlling waveform elements ahead of an attack portion and waveform elements of a release portion
abstract fullSony CorporationAssign./Filed: Oct. 26, 1999/ Feb. 21, 1996
ATRAC2/3 Gain Control.

US06138101Method of encoding digital data
abstract fullSharp CorporationAssign./Filed: Oct. 24, 2000/ Dec. 4, 1997
Improvement to ATRAC which allows a more flexible interpretation of "minimum limit of audibility" depending upon the signal characteristics.

Compression, other

US04516258Bit allocation generator for adaptive transform coder
abstract fullAT&T Bell LaboratoriesAssign./Filed: May 7, 1985/ June 30, 1982
Adaptive bit allocation scheme for transform speech encoders. Seems to predate using perceptual distortion criteria.

US05109417Low bit rate transform coder, decoder, and encoder/decoder for high-quality audio
abstract fullDolby Laboratories Licensing CorporationAssign./Filed: April 28, 1992/ Dec. 29, 1989
Use of block floating representation and adaptive bit allocation for encoding high quality audio. Gives nicely detailed, general coverage of transform coding.

US05142656Low bit rate transform coder, decoder, and encoder/decoder for high-quality audio
abstract fullDolby Laboratories Licensing CorporationAssign./Filed: Aug. 25, 1992/ Nov. 4, 1991
Fancy adaptive bit allocation method using fixed offsets (seems a lot like the one ATRAC uses). Appears to be large overlap with US05109417.

US05166686Variable length block coding with changing characteristics of input samples
abstract fullNEC CorporationAssign./Filed: Nov. 24, 1992/ June 29, 1990
Transform coding with adaptable input block size.

US05197087Signal encoding apparatus
abstract fullnoneAssign./Filed: March 23, 1993/ July 18, 1990
Transform coding with adaptable input block size.

US05222189Low time-delay transform coder, decoder, and encoder/decoder for high-quality audio
abstract fullDolby Laboratories Licensing CorporationAssign./Filed: June 22, 1993/ Sept. 26, 1990
High quality audio at 128kbps with a very short block size (128 samples). Again, considerable overlap (read: boilerplate) with previous Dolby patents.

US05235623Adaptive transform coding by selecting optimum block lengths according to variatons between successive blocks
abstract fullNEC CorporationAssign./Filed: Aug. 10, 1993/ Nov. 14, 1990
Transform coding with adaptable input block size.

US05263088Adaptive bit assignment transform coding according to power distribution of transform coefficients
abstract fullNEC CorporationAssign./Filed: Nov. 16, 1993/ July 12, 1991
Adaptive bit assignment algorithm for transform coding.


US05268882Magnetic head holding apparatus
abstract fullSony CorporationAssign./Filed: Dec. 7, 1993/ Dec. 8, 1992
Mechanical design and mounting of the overwrite head.

US05341357Optical disc recording apparatus
abstract fullSony CorporationAssign./Filed: Aug. 23, 1994/ Dec. 11, 1991
Method for disabling the eject button when the TOC is being written.

US05539717Player for reproducing both minidisc and compact disc
abstract fullDaewoo Electronics Co., Ltd.Assign./Filed: July 23, 1996/ Dec. 13, 1994
Covers the mechanics of a transport for both CD and MD.

US05583834Mini disc player
abstract fullSony CorporationAssign./Filed: Dec. 10, 1996/ Jan. 17, 1996
Mechanical design of MZ-R2.

US06009062Disc player for minidisc and compact disc playback
abstract fullVictor Company of Japan, Ltd.Assign./Filed: Dec. 28, 1999/ June 4, 1998
Mechanism for combination MD/CD drive. Appears to be the basis for the JVC KD-MX3000. Contains detailed mechanical drawings of the drive.


US04608676Apparatus for optically reproducing an information signal from a record disk
abstract fullSony CorporationAssign./Filed: Aug. 26, 1986/ March 26, 1985
Relates to the positioning of an optical head for a CD player.

US05003521Optical disk discriminating device
abstract fullSony CorporationAssign./Filed: March 26, 1991/ Aug. 18, 1988
Discriminating between recordable and pre-recorded discs.

US05012461Disk recording apparatus for re-establishing a recording mode at a desired address
abstract fullSony CorporationAssign./Filed: April 30, 1991/ Oct. 21, 1988
Detecting mis-tracking during recording (by watching the ADIP addresses).

US05357498Disc drive apparatus that positions an objective lens within a disc cartridge at the time when the disc is rotated
abstract fullSony CorporationAssign./Filed: Oct. 18, 1994/ Sept. 14, 1992
Optical head arrangment where the head is moved close to the disk through the shutter opening in the cartridge.

US05428596Optical pickup apparatus
abstract fullSony CorporationAssign./Filed: June 27, 1995/ June 23, 1994
Details of the MD optical pickup.

US05475537Optical system for use in recording and reading information on an optical information medium
abstract fullKonica CorporationAssign./Filed: Dec. 12, 1995/ Feb. 28, 1994
Optical pickup optics.

US05644563Optical pickup system
abstract fullLG Electronics Inc.Assign./Filed: July 1, 1997/ June 7, 1995
Optical pickup details.

US05673247Optical pickup having two objective lenses
abstract fullSharp CorporationAssign./Filed: Sept. 30, 1997/ Nov. 27, 1996
Double lens optical pickup. Good drawings of the optical path details.

US05737297Optical head
abstract fullSharp CorporationAssign./Filed: April 7, 1998/ Feb. 11, 1997
Improved MD optical head.

US05844882Recording medium, address recording method and apparatus, and recording/reproducing method and apparatus for reducing crosstalk of addressing signals
abstract fullSony CorporationAssign./Filed: Dec. 1, 1998/ March 17, 1997
Improvement to allow accurate, low cross-talk ADIP tracking even with small track pitch. (Beneficial for 80 minute blanks with 1.5um pitch?). Includes very careful description of how ADIP tracking is accomplished.

Physical disc

US04907216Optical record carrier having position indentifying track modulation
abstract fullU.S. Philips CorporationAssign./Filed: March 6, 1990/ Dec. 9, 1987
Method for storing address information in a recordable disc's pregroove. Different from MDs modulated ADIP wobble however.

US04910622Over write capable magnetooptical recording medium
abstract fullNikon CorporationAssign./Filed: March 20, 1990/ May 10, 1988
Magnetic overwrite system in which 2 bits can be stored per magnetic domain.

US05050145Optical disk recording and reproducing apparatus having faster reproducing speed than recording speed
abstract fullSony CorporationAssign./Filed: Sept. 17, 1991/ Jan. 22, 1990
CD-MO system in which playback rotational speed is higher than recording rotational speed.

US05400316High density small-diameter magnetic optical disk
abstract fullSony CorporationAssign./Filed: March 21, 1995/ Aug. 15, 1991
Coverage of the MD substrate, and methods for molding it. By reducing double refraction the inner circumfrences of the disc are made available for recording.

US05461597Mastering apparatus for producing compact disk and minidisk master disks
abstract fullSony CorporationAssign./Filed: Oct. 24, 1995/ June 29, 1993
Description of the Minidisc mastering process.

US05506023Magneto-optical disc
abstract fullSony CorporationAssign./Filed: April 9, 1996/ Aug. 26, 1994
Optical disc with description of the lubrication layer for the magnetic head.

USRE034710Magneto-optical recording apparatus
abstract fullSony CorporationAssign./Filed: Aug. 30, 1994/ July 16, 1993
Patent for magnetic overwrite recording and direct contact head.

Disc low level data (Error correction interleave, etc.)

US04858217Optical disk recording and reproducing device
abstract fullSony CorporationAssign./Filed: Aug. 15, 1989/ Nov. 16, 1987
Recordable CD patent. Relates to handling of the long interleaved CIRC when a new audio segment is recorded.

US05224087Apparatus for recording compressed digital information to an optical disc
abstract fullSony CorporationAssign./Filed: June 29, 1993/ Aug. 19, 1991
Use of shock memory for compressed audio, plus interleave issues. This is an ur-Minidisc patent, discussing recording of compressed audio to optical disk, albeit with an unprotected carrier (see discussion starting page 11).

US05243588Method and apparatus for reading digital data bursts comprising data clusters and cluster linking sectors
abstract fullSony CorporationAssign./Filed: Sept. 7, 1993/ Aug. 16, 1991
Similar to US05224087, discussing the necessity of the cluster-linking sector (used as a place for the error correction code to run out).

US05363362Apparatus for reproducing recorded data comprising interleaved clusters and cluster linking sectors
abstract fullSony CorporationAssign./Filed: Nov. 8, 1994/ April 15, 1993
Similar to US05224087 and US05243588, discussing the necessity of the cluster-linking sector (used as a place for the error correction code to run out).

US05528570Apparatus for recording and reproducing data on a magneto-optical disc at a data transfer rate which is the same as that of data reproduced from a compact disc
abstract fullSony CorporationAssign./Filed: June 18, 1996/ Feb. 24, 1994
MD-Data related. Nice explanation of the long interleave and the reason for link sectors. Detailed description of the MD's physical data level.

Disk data layout

US05058096Disk recording/reproducing apparatus and disk recording/reproducing method
abstract fullSony CorporationAssign./Filed: Oct. 15, 1991/ Nov. 9, 1988
Write inhibit mechanism for recordable CD, using flags in a special region of the disk.

US05142521Recording/reproducing device
abstract fullSharp CorporationAssign./Filed: Aug. 25, 1992/ May 25, 1990
Recordable CD which allows data at various sampling rates to be recorded.


US04862439Recording device that identifies recordable areas of a disk record
abstract fullSony CorporationAssign./Filed: Aug. 29, 1989/ Jan. 19, 1988
How to use TOC information to determine where there is available recording space on a medium; apparently for recordable CD.

US05038231Recording and reproducing apparatus which repositions table of contents information from one area to another on the medium
abstract fullCanon CorporationAssign./Filed: Aug. 6, 1991/ Jan. 24, 1990
Recording a TOC on tape (DAT, etc).

US05153861Recording/reproducing device
abstract fullSharp CorporationAssign./Filed: Oct. 6, 1992/ Dec. 13, 1989
Allow user information to be added to the TOC of recordable CD.

US05274617Method and device for data management in an optical recording medium
abstract fullSharp CorporationAssign./Filed: Dec. 28, 1993/ May 25, 1990
Method of detecting and doing something useful in cases where the TOC is out of date with respect to the disc contents.

US05388093Disc recording and/or reproducing apparatus for recording continuous compressed data in plural data regions and disc therefor
abstract fullSony CorporationAssign./Filed: Feb. 7, 1995/ Sept. 16, 1992
General Minidisc description that includes details of the TOC layout. Some commonality with US05363362.

US05392265Recording and reproducing apparatus which calculates and displays management information of recorded segments
abstract fullSony CorporationAssign./Filed: Feb. 21, 1995/ May 17, 1993
Use of TOC information to display playing time of a track, total playing time, and recording time remaining. Includes careful description of TOC contents.

US05521900Disk having a lead-in region containing display data and an apparatus for recording and/or reproducing the disc
abstract fullSony CorporationAssign./Filed: May 28, 1996/ Dec. 21, 1993
Details of the TOC (but perhaps not the current MD TOC). Similar to US05214631.

US05537387Information storage disk with display data recorded in a lead-in region and an apparatus for recording and/reproducing the disc
abstract fullSony CorporationAssign./Filed: July 16, 1996/ May 11, 1995
TOC related. Very similar to US05521900.

Shock-proof memory

US05148417Tracking jump compensator for optical disc reproducing apparatus
abstract fullSony CorporationAssign./Filed: Sept. 15, 1992/ April 23, 1990
Shock proof memory (embodiment in CD).

US05214631Disc recording/reproducing apparatus having a servo system capable of successively recording and reproducing tracks on a disc irrespective of turbulence of the servo system due to a disturbance
abstract fullSony CorporationAssign./Filed: May 25, 1993/ June 19, 1991
Shock proof memory as it applies to CD-I (CD Interactive). Interesting discussion of CD-I audio modes.

US05331617Audio data recording/reproduction device having digital high speed dubbing function and audio data dubbing system using such devices
abstract fullSanyo Electric Co., Ltd.Assign./Filed: July 19, 1994/ May 27, 1993
Contains diagrams of shock proof memory levels as the memory drains and refills.

US05317553Optical disc recording and/or reproducing apparatus having a buffer memory to accommodate track jumps
abstract fullSony CorporationAssign./Filed: May 31, 1994/ Aug. 15, 1991
Minidisc - shock proof memory.

US05680379Information reproduction apparatus having means to control maximum delay of information being read from memory
abstract fullMitsubishi Denki CorporationAssign./Filed: Oct. 21, 1997/ April 19, 1993
Shock-proof buffer management technique to reduce mute time during inadvertent track skip and upon user initiated disk change.

MD equipment internal control logic

US05222054Seeking operation control apparatus in an optical disk reader
abstract fullFunai Electric Co., Ltd.Assign./Filed: June 22, 1993/ Sept. 17, 1991
Optimization of track jump operations, by calculating the number of tracks that need to be skipped.

US05343452Data recording/reproducing apparatus of simultaneously performing both reproducing and recording from and in a single recording medium
abstract fullSharp CorporationAssign./Filed: Aug. 30, 1994/ Nov. 19, 1992
Method for playing back and recording simultaneously. The MDS-DRE1 must have used a scheme such as this.

US05508984Optical disc player having program title display
abstract fullCorporation KenwoodAssign./Filed: April 16, 1996/ Oct. 28, 1993
Method of displaying TRACK TIME or TRACK NAME by use of a user key.

US05563861Optical disc recording apparatus which controls re-recording after a disturbance as a function of the frequency of the detected disturbance
abstract fullSony CorporationAssign./Filed: Oct. 8, 1996/ May 11, 1995
Related to detecting track jumps and re-recording affected sections. Good description of physical level recording and playback functions.

US05568625Time conversion method of mini discs using multiple time tables
abstract fullSamsung Electronics Co., Ltd.Assign./Filed: Oct. 22, 1996/ Oct. 31, 1994
Method for converting MD physical addresses to hours, minutes and seconds..

US05699336Reproducing apparatus having buffer memory and capable of rapidly restarting reproduction and method of controlling the apparatus
abstract fullSony CorporationAssign./Filed: Dec. 16, 1997/ Jan. 18, 1996
Decrease track-seek delay in portables by storing beginning of next track and beginning of previous track in shock-proof memory, so that if the user issues a track-seek, the adjacent track can be immediately played out while waiting for the optical head to power up, seek to position, and begin reading.

US05706262Recording and reproducing apparatus that allows user reordering of the sequence that data is reproduced from the disc and that automatically reorders the remaining data after data defined by the user has been erased
abstract fullSony CorporationAssign./Filed: Jan. 6, 1998/ Aug. 1, 1996
Method to allow users to delete or renumber multiple tracks at once, reducing confusion caused by tracks changing their numbering when these operations are attempted one at a time.

US05889745Method for calculating a play time of a disc reproducing apparatus
abstract fullSony CorporationAssign./Filed: March 30, 1999/ May 18, 1993
Calculating play time by finding the number of clusters in a track.

Power conservation

US05502700Power saving method and apparatus for intermittently reading reproduction apparatus
abstract fullSony CorporationAssign./Filed: March 26, 1996/ Sept. 28, 1994
Power conservation by turning off the motor when the shock-memory is full enough.

US05615187Power saving method and apparatus for intermittently reading reproduction apparatus
abstract fullSony CorporationAssign./Filed: March 25, 1997/ Sept. 28, 1994
Saving power during recording by stopping the disc while the shock proof memory fills.

Multitrack and music related

US05590100Information recording/reproducing technique to record plural-channel information for subsequent simultaneous reproduction
abstract fullYamaha CorporationAssign./Filed: Dec. 31, 1996/ May 17, 1995
Multitrack audio recording to Minidisc.

US05602811Musical information recording and reproducing technique for use with a recording medium having a UTOC area
abstract fullYamaha CorporationAssign./Filed: Feb. 11, 1997/ Aug. 2, 1995
Relates to multitrack recording and display of a musical piece's current measure.

US05784349Musical information recording and reproducing technique for use with a recording medium
abstract fullYamaha CorporationAssign./Filed: July 21, 1998/ Aug. 28, 1996
Relates to multitrack recording and display of a musical piece's current measure. Similarity to US05602811.

Far out/extensions

US05546369Optical disk system for recording and reproducing a mini disk and standard compact discs
abstract fullSamsung Electronics Co., Ltd.Assign./Filed: Aug. 13, 1996/ March 30, 1995
CD and MD recorder with the ability to store ATRAC data on a CD.

US05592449Disc apparatus using character-based control codes in a table of contents
abstract fullCorporation KenwoodAssign./Filed: Jan. 7, 1997/ Nov. 14, 1995
Using character information placed in the track title area to control devices external to the MD player.

US05689704Recording medium, recording/playback device which uses commands in character string form for audio system control
abstract fullSony CorporationAssign./Filed: Nov. 18, 1997/ May 18, 1995
Scheme for adding interactivity (as with CD-I) to MD equipment by storing equipment control commands on an MD. Functions such as playback, recording, editing, as well as computation, could be undertaken according to control information recorded on the MD. Contains a drawing of the MZ-1 and detailed information on the TOC contents.

US05856930Disc-shaped recording medium, disc recording apparatus and disc reproducing apparatus
abstract fullSony CorporationAssign./Filed: Jan. 5, 1999/ Nov. 14, 1994
Technique to be used when encoding MPEG video on Minidisc, placing I frames and B frames strategically with respect to linking sectors. Contains interesting drawing of pocket Minidisc video viewer ("MD Watchman"?).

US05901119Recording apparatus, playback apparatus and recording medium having a management area with program position and playback information
abstract fullSony CorporationAssign./Filed: May 4, 1999/ Aug. 18, 1997
Use of a previously unused region of the MD to store various disc-based settings, such as program play order, and track "quick-start" indication (this being a mode used in sound effects applications wherein the audio at the beginning of a track is held in buffer memory to provide immediate playback at the push of a button). (Does the Tascam pro deck use this?)

US05940352Record medium device for recording and reproducing time codes synchronized with input/reproduction signals into and from record medium having UTOC area, and record medium having UTOC area
abstract fullNippon Columbia Co. Ltd.Assign./Filed: Aug. 17, 1999/ Sept. 18, 1997
Method for recording video timecodes to Minidisc, storing them in the UTOC. (Nippon Columbia is otherwise known as Denon).

US06097557Method and apparatus for recording compressed audio data on recording medium and method for transferring compressed audio data
abstract fullSony CorporationAssign./Filed: Aug. 1, 2000/ May 27, 1998
Method for updating the U-TOC in a Minidisc Kiosk based music delivery system. Here they describe that the local Kiosk equipment should, after recording the compressed audio data to the disc, determine the new U-TOC contents, rather than having the central server determine this. (Seems rather obvious).


US04932016Apparatus and method of recording and reproducing data using a disk
abstract fullSony CorporationAssign./Filed: June 5, 1990/ June 2, 1988
Finding and recording the start and end times of audio being recorded. For recordable CD.

US05963521Recording and/or reproducing method and apparatus with dubbing mode
abstract fullSony CorporationAssign./Filed: Oct. 5, 1999/ Sept. 11, 1998
High speed dubbing in the ATRAC domain.

US06205104Recording/reproducing apparatus for compressed data
abstract fullSony CorporationAssign./Filed: March 20, 2001/ Sept. 29, 1993
High speed dubbing in the ATRAC domain.

US06005659Mini-disc laser power meter and method of making the same
abstract fullSony CorporationAssign./Filed: Dec. 21, 1999/ Dec. 15, 1998
MD Laser power meter with the sensor unit in the shape of a Minidisc cartridge. The sensor can be inserted in a piece of MD equipment for laser power measurement without requiring any disassembly.

US06035367Computer file system providing looped file structure for post-occurrence data collection of asynchronous events
abstract fullAvid Technology, Inc.Assign./Filed: March 7, 2000/ April 3, 1997
Relates to storing video on a hard disk in much the way that the Minidisc "Time machine" recording function works. Interestingly, this patent references!), refering to information there about the Sony MDS-503.

US06157434Movie film having two digital audio data recording areas along its longitudinal direction
abstract fullSony CorporationAssign./Filed: Dec. 5, 2000/ Dec. 13, 1993
Method of recording ATRAC on movie film.

Design (ornamental)

USD0364884Video camera combined with optical magnetic disc recorder
abstract fullSony CorporationAssign./Filed: Dec. 5, 1995/ March 25, 1994
Design patent of MD based camcorder (ornamental drawings only, no technology development).

USD0368908Optical and magnetic disc recorder
abstract fullSony CorporationAssign./Filed: April 16, 1996/ Dec. 27, 1994
Design patent for MDH-10 MD data drive.

US05320221Transport and protective case for information medium
abstract fullKurz Kunststoffe GmbHAssign./Filed: June 14, 1994/ May 27, 1993
Minidisc carrying case.

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