Tdk Corporation

Tdk Electronics Company, Limited

Imperial Chemical Industries Limited

Toshiki Aoi

Kenryo Namba

Akihiko Kuroiwa

Kazuo Takahashi

Shigeru Asami

Hajime Utsunomiya

Hiroyuki Arioka

Masahiro Shinkai

Mamoru Usami

Akio Ogawa

Shiro Nakagawa

Isamu Kuribayashi

Masanori Shibahara

Atsuko Motai

Takashi Kikukawa

Narutoshi Fukuzawa

Atsuko Kosuda

Suguru Takayama

Tetsushi Inoue

Tatsuhiro Kobayashi

Paul F Gordon

Kenji Uchiyama

Noriko Takeda

Shuji Tsukamoto

Peter J Duggan

Hideki Dohi

Sinichi Tezuka

Stephen J Abbott

Tezumbumi Kamijo

Yasukawa Koji

In a data recording and readingout system in which data is recorded and readout, or is readout on, or from an optical recording mediumby irradiating a laser beam having a wavelength '&#x3bb;' via an objective lens of a numerical aperture 'NA' onto said optical recording medium, while the optical recording medium contains a layered structure formed by sandwiching a dielectric layerbetween a recording layerand an optical absorption layerwith respect to the optical recording mediumarranged in such a manner that data recorded by a recorded mark train can be readout and the recorded mark train contains a recorded mark smaller than, or equal to a limit of resolution, the laser beam is irradiated via the objective lens and a solid immersion lens having a refractive index &#x201c;n&#x201d; which is positioned between the optical recording medium and the objective lens, so that the data is recorded and readout, or is readout with respect to the optical recording medium by a recorded mark train which contains a recorded mark smaller than, equal to &#x201c;&#x3bb;&#x201d;/(4&#xb7;n&#xb7;NA).&#x201d;

Data recording and readingout system

The optical recording medium of the present invention is a phase change optical recording medium which can be used as a write once medium and which can be recorded at a high recording density. The optical recording medium of the present invention is adapted for recording such that, when the recording beam has a wavelength of &#x3bb;, and objective lens of recording optical system has a numerical aperture of NA, minimum record marks formed are circular or ellipsoidal marks having a length of 0.4 &#x3bb;/NA or less; and the medium is a write once medium wherein the recorded information can not be erased or rewritten at the minimum linear velocity used.

Optical recording medium

In a phase change optical recording medium, time required for recording the unrecorded area as well as jitter produced are reduced. Provided is an optical recording method for recording an optical recording medium having a phase change recording layer, wherein the recording is conducted such that: V /V >1, and 0.3<P /P <1 when unrecorded area of the recording layer is recorded by using a linear velocity of V and an erasing power of P and overwritten by using a linear velocity of V and an erasing power of P ,

Optical recording method, optical recording apparatus, and optical recording medium

An optical recording medium adapted for high density recording with a light of short wavelength which exhibits excellent jitter properties, and its recording method are provided. The optical recording medium recorded and/or reproduced with a light at a wavelength of 600 to 680 nm comprises a substrate having grooves formed on its surface at a track pitch of up to 0.8 .mu.m, and a recording layer containing an organic die disposed on the substrate. Depth A and width B of the groove (.mu.m) and leveling ratio C are in the relation:

Optical recording medium for use at short wavelengths and its recording

In an optical recording disk comprising a reflective layer in close contact with a recording layer, the recording layer contains a phthalocyanine dye and a second dye having a lower heat decomposition temperature than the phthalocyanine dye. By virtue of a depression of heat decomposition temperature, recording sensitivity is improved.

Optical recording disk

With a dye recording layer having an index of refraction n of 2.0 to 2.6 formed on a substrate, that portion of the recording layer disposed in a groove is used as a recording track by restricting the groove to a width W.sub.G of 0.38 to 0.45 .mu.m and a depth D.sub.G of 1000 to 1700 .ANG. and that portion of the recording layer in the groove to a thickness T.sub.G of at least 2000 .ANG. for 2.0.ltoreq.n.ltoreq.2.3 or to W.sub.G of 0.38 to 0.45 .mu.m, D.sub.G of 1000 to 2300 .ANG., and T.sub.G of at least 2500 .ANG. for 2.3&lt;n.ltoreq.2.6. Reproduction is performed by means of a CD player which is adapted to perform tracking control by detecting a tracking error signal by the differential phase technique. There is obtained a tracking control loop gain of -2 dB or higher relative to that of commercially available CD, ensuring stable and accurate tracking control.

Method of use for an optical recording disk with a dye-containing

In an optical recording medium comprising an organic dye base recording layer and a reflective layer on a resin substrate having a groove of 1,100 to 2,300 .ANG. deep formed in one surface thereof, signals are written by directing recording light to the recording layer within the groove from the back side of the substrate at a relative linear velocity of at least 3.6 m/s whereby record marks are formed in the recording layer as a result of partial decomposition of the dye while deforming the groove bottom surface. The deformation of the groove bottom surface is minimized to less than 18% of the groove depth. The medium requires a short time for recording and offers reduced jitter on reproduction.

Optical recording/reproducing method

An optical recording disk includes a dye base recording layer, an intermediate layer, and a reflective layer on a substrate in the described order. The reflective layer is composed of one or more metal elements, for example, copper alloy, and the intermediate layer contains a compound of the one metal element or a compound of at least one of the metal elements, for example copper oxide. The intermediate layer minimizes undesirable interactions between the recording and reflective layers.

An optical recording disk includes on a substrate 2, a dye recording layer 3, a lower reflective lamina 4, an upper reflective lamina 5, and a protective coat 6. The lower reflective lamina 4 is formed of Au, Pt, Ag, Al or an alloy thereof and the upper reflective lamina 5 is of a stainless steel composition or an alloy containing 30 wt % or more of Cu and at least one element selected from the group consisting of Zn, Ti, V, Ta, Cr, Mo, W, Mn, Fe, Co, Rh, Ni, Pd, Pt, Ag, Au, Al, Sn, Si, Pb, Cd, Hg, Ca, In, As, Sb, Bi, Se, Te, Ge, N and O. The disk is well reliable and less costly.

In preparing an optical recording disk by spin coating a dye-containing solution to an annular substrate to form a recording layer thereon, a circular channel is preformed in the substrate in proximity to the inner peripheral edge of the substrate for defining an inner boundary of the recording layer. Then the recording layer is free of corrugations near its inner boundary, leading to improved adhesion of an overlying protective film and a minimal variation in reflectivity.

In an optical recording disk 1 comprising a dye layer 2 formed on a substrate 3 as a light absorbing layer and a reflective layer 4 stacked thereon, tracking servo control is carried out by the push-pull method. To produce normal and accurate tracking error signals, the surface of the dye layer 2 includes depressed and raised sections corresponding to grooves 31 and lands 35 and .DELTA.D which is given by the formula:

An optical recording disk intended for use as an additionally recordable CD is provided. It has a substrate, a dye or recording layer on the substrate, and a reflective layer and a protective layer disposed on the recording layer in a close contact relationship. Recording is carried out by directing recording light to the recording layer to form a pit and reproduction is carried out by directing reproducing light to the pit. A layer containing a decomposition product of the dye or recording material, but substantially free of the substrate material is present at the interface between the substrate and the recording layer where the pit is formed.

A pit-forming optical recording medium comprises a substrate supporting a film of optically deformable recording material comprising an organic dye for absorbing optical signals of modulated electromagnetic radiation applied to the film and thereby causing corresponding deformations of the film when the signal intensities exceed predetermined threshold levels. The dye is a phthalocyanine compound or mixture of phtalocyanine compounds in which each of at least five of the peripheral carbon atoms in the 1, 4, 5, 8,9, 12, 13 or 16 positions (the '3,6-positions') of the phthalocyanine nucleus, as shown in Formula I, is linked by an atom from Group VB or Group VIB of the Periodic Table to a carbon atom of an organic radical. In preferred compounds each of the eight 3,6-positions is linked by an atom from Group VB or Group VIB, especially sulphur, selenium or nitrogen, to an organic radical. ##STR1##

A pit-forming optical recording media and process for producing the same

An optical recording medium comprising a pair of substrates each having an electrode, the space between the substrate is filled with a high-dielectric liquid crystal to form a rewritable recording layer. The recording medium comprises radiation absorbing means to provide a change of directional orientation of the liquid crystal upon exposure to a laser beam.

Optical recording medium having a liquid crystal layer

An optical recording disk wherein information is written and reproduced through the application of recording and reading laser beams is assembled by preparing a pair of circular substrates which each are provided with a plurality of studs or spikes on outer and/or inner circumferential band, forming a recording layer of dye on each substrate, and joining the substrates together through the studs by ultrasonic sealing or adhesive bonding such that the recording layers face one another via an interior space.

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Nagano, Japan

Toshiki Aoi