Abstract: An information recording medium including a substrate having a tiny pattern of serial groove portion and land portion alternately formed in parallel, a recording layer composed of recording material formed on the tiny pattern of the substrate, and a transparent layer formed on the recording layer, having the thickness of 0.05 to 0.4 mm, wherein the tiny pattern is formed under condition of P≦&lgr;/NA that P is a pitch of the groove portion and the land portion, &lgr; is a wavelength of a laser light for reproducing information from the information recording medium, NA is a numerical aperture of an objective lens for outputting the laser light for reproducing information from the information recording medium, and a reference clock is recorded windingly in the land portion as a sine waveform.

Abstract: An optical recording medium having a laminated structure portion(4) including a light-emission layer(3) and a recording layer(2). The light-emission layer(3) is made of a light-emission material excited by reproducing laser light to emit fluorescent light, and the recording layer(2) is made of a material in which at least a refractive index or an absorption coefficient can be changed relative to light emitted from the light-emission layer by recording laser light. The recording layer(2) is disposed to be closer to a side into which reproducing laser light is introduced than the light-emission layer(3). Then, recorded information recorded on the recording layer by the change of the refractive index or the absorption coefficient is read out from the recording layer as the change of intensity of light emitted from the light-emission layer(3) when it is irradiated with reproducing laser light. This optical recording medium can realize an optical memory which can generate a reproduced signal with a high S/N.

Abstract: A multi-layered optical disc having its recording unit comprised of plural information recording layers, in which two or more information recording layers are layered on a substrate 0.3 to 1.2 mm in thickness, with the interposition of a transparent layer, to from a recording unit, a light transmitting protective layer is formed on the recording unit to a thickness of 10 to 177 &mgr;m, and in which the light is illuminated from the side of the light transmitting protective layer to effect recording and/or reproduction of information signals. At least one of the information recording layers except the information recording layer formed at a remotest position from the light transmitting protective layer has a phase change material as a recording material.

Abstract: Provided is a medium for recording optical information and a method for recording optical information that allow recording sensitivity to be increased, and particularly a prescribed recording sensitivity to be maintained together with reflectivity and other playback characteristics during high-speed recording, by employing the temperature dependence of recording sensitivity of the light-absorbing layer instead of the light attenuation coefficient of the light-absorbing layer, and selecting a material which is prone to increased absorption of a laser beam at high temperatures during recording. A distinctive feature is that the absorbance or recording sensitivity of the dye material film used in the medium for recording optical information that has a writable structure is dependent on temperature. Specifically, it was found that the absorption spectrum of the dye material varies at high temperatures, and a relation A2/A1≧1.30 was established.

Abstract: A method of photolithography using super-resolution near-field structure. A super-resolution near-field structure is formed on a semiconductor chip comprising a substrate and a photoresist layer thereon. An incident light beam penetrates through the super-resolution near-field structure to expose the photoresist layer. While penetrating through the super-resolution near field structure, the intensity of the incident light beam is increased, and the aperture of the light beam is reduced. As a result, the line width of the pattern formed on the photoresist layer is narrowed. The super-resolution near-field structure has a first dielectric layer, a second dielectric layer and an active layer sandwiched between the first and the second dielectric layers. The active layer is formed of one of gallium (Ga), germanium (Ge), arsenic (As), selenium (Se), indium (In), tin (Sn), antimony (Sb), tellurium (Te), and silver (Ag).

Abstract: A multilevel phase change optical recording medium comprises first to N-th (N≧2) phase change optical recording layers, wherein an i-th recording layer and a j-th recording layer, which are two recording layers arbitrarily selected from the first to N-th recording layers, meet the conditions of Ti>Tmi and &tgr;wi<&tgr;xi, and Tj<Tmj or &tgr;wj>&tgr;xj, with respect to a particular recording laser beam selected from recording laser beams having different power levels, where T is the maximum temperature of the recording layer in a recording operation, Tm is the melting point of the recording layer, Tx is the crystallizing temperature of the recording layer, &tgr;w is a time required for the recording layer to be cooled down from Tm to Tx after the laser beam irradiation, and &tgr;x is the crystallizing time of the recording layer.

Abstract: Optical data carrier comprising a preferably transparent substrate which may, if desired, have previously been coated with a protective layer and to whose surface a light-writable information layer, if desired a protective layer, if desired an adhesive layer and finally a covering layer have been applied, which can be written on and read by means of blue light, preferably laser light, where the information layer comprises a light-absorbent compound, characterized in that at least one dye which cyclizes thermally is used as light-absorbent compound.

Abstract: The invention provides: an optical recording medium having the changeability and compatibility of media and a large capacity in three dimensions; an optical pickup apparatus for the same and a control apparatus for the same.

Abstract: An optical recording medium having at least a light-transmitting substrate, a recording layer recorded by heat mode recording, and a reflective layer comprising a metal or a semimetal disposed in this order exhibiting reduced signal noise in the reading and improved recording characteristics are provided. A method for producing such optical recording medium is also provided, and this method includes the step of changing bonding state of the element(s) constituting the reflective layer at least in the area to be recorded.

Abstract: An apparatus for retrieving information stored on an optical disk as colored dots, using an array of laser diodes emitting multiple wavelengths. Colored dots store more information than pits and spaces on optical disks because each colored dot represents a multiple-bit code of information rather than a single bit. The optical disk reader directs multiple wavelength diode laser beams to the disk surface. The reflected beams are then separated using an array of dichroic filters, and sent to light sensors. The light sensors identify the intensity of each of the reflected frequencies and determine the wavelength combination being reflected from the optical disk, which corresponds to a multiple-bit code.

Abstract: This invention relates to an optical disc recording apparatus, an optical disc recording method, and an optical disc, and the present invention is applied to, for example, apparatus for recording on a compact disc, compact discs, and compact disc players, and sub-data strings are recorded so that the main data strings is reproducible by an optical pickup for reproducing the main data string and the main data strings are protected from being copied illegally without any adverse effect on reproduction of the pit-and-land main data strings. The sub-data string ED is recorded by locally changing the reflectance of the reflection film in the form of irregularity such as pit or mark at the timing which does not affect the position information of the edge.

Abstract: In a write once optical recording medium comprising a recording layer and a light transmitting protective layer formed successively on a supporting body, for recording and reproduction by irradiating a laser beam of a 380 to 450 nm wavelength from the light transmitting protective layer side, &lgr;max≦370 nm on the premise that the wavelength providing the peak optical absorption coefficient of the recording layer is defined to be &lgr;max.

Abstract: An optical recording medium for at least one of recording and reproduction of information by focusing of light from an optical system on a recording layer, comprising a substrate, a recording layer formed on the substrate, a first protective layer formed on the recording layer, and an antireflection multilayer film, designed to be positioned at a near field distance from the optical system, formed on the first protective layer for preventing reflection of the light at the surface of the first protective layer and having predetermined optical characteristics for moderating a change of a reproduced signal intensity along with fluctuation of a distance between the antireflection multilayer film and the optical system, a method of producing the medium, and an optical recording and reproduction device including the medium.

Abstract: An optical information medium (20) for erasable recording by means of a laser-light beam (10) is provided. A substrate (1) holds a stack (2) of layers with a phase-change recording layer (5) between a first dielectric layer (4) and a second dielectric layer (6). A light-absorptive layer (7) is present proximate the recording layer (5) and is made of a compound of the formula QRx, in which Q is the element Si, Ge, Ti, Zr, Hf, Nb or Ta, R is the element O or N, and 0<x≦2.5, in order to achieve that 0.8<Ac/Aa<1.50, in which Ac and Aa are the respective quantities of laser-light absorbed in the recording layer (5) in the crystalline state and the amorphous state at a laser-light wavelength selected from a range of 350-450 nm. Thus high data rates and low data jitters are achieved at this short wavelength range by tuning x to an optimal value during manufacture of the optical information medium.

Abstract: A recording medium includes a first substance and a second substance at least in which the first and second substances undergo an oxidation-reduction reaction when an external energy is applied, thereby recording information by varying the optical characteristics. In the recording medium, the reaction of the first and second substances is suppressed, reaction which degrades the recording characteristics other than the case where the recording medium is subjected to recording. In an optical disk 100 (i.e., the recording medium), a WO3 film 2 (i.e., a second substance), a C film 3 (i.e., a third substance) and an Sn-10 atomic % Sr film 4 (i.e., a first substance) are formed successively on a substrate 1. When the recording medium is irradiated with a recording laser beam as an external energy, the WO3 forming the film 2 is reduced to WO2.

Abstract: There is disclosed an optical recording medium having at least a recording layer provided on a light-transmissive substrate having grooves and lands with prepits, wherein said lands are generally rectangular or trapezoidal in cross section having a top surface and sidewalls, as well as a specified land height (h1), and said prepits are formed in a land in the center area of the land in a width direction thereof, and spaced from the adjacent grooves by boundary walls of a specified height (h2). The optical recording medium permits address information and disc rotation control information to be accessed accurately even if a track pitch is small, and which still can be manufactured efficiently, with the added capability of signal recording in high density and reproduction of high-quality signals.

Abstract: An optical memory system includes memory cells which utilize synthetic DNA as a component of the information storage mechanism. In the preferred embodiment, memory cells contain one or more chromophoric memory units attached to a support substrate. Each chromophoric memory unit comprises a donor, an acceptor and, at some time during its existence, an active quencher associated with the donor and/or the acceptor. The donor and the acceptor permit non-radiative energy transfer, preferably by Förster energy transfer. To write to the memory cell, the quencher is rendered inactive, preferably by illumination with ultraviolet light. To read, the chromophoric memory units in a read portal are illuminated, and the read illumination is detected. In the preferred embodiment, multiple chromophoric memory units having resolvable read properties are contained within a single read portal. In this way, a multibit word of data may be read from a single diffraction limited read portal.

Abstract: The object of the present invention is to provide an optical recording medium which is excellent in the recording sensitivity and suitable for the high speed recording.

Abstract: The present invention discloses optical recording elements having optical recording layers containing tetra dyes. The dyes have metallized azo dianionic dye with cationic dye counterions. The recording layer has a thickness from 225 to 300 nm.

Abstract: A magneto-optical recording medium includes at least a first magnetic layer, a second magnetic layer and a third magnetic layer which are layered in this order, the first magnetic layer being formed of a perpendicularly magnetized film having a relatively small wall coercivity and a relatively large wall mobility compared with the third magnetic layer in the vicinity of a predetermined temperature, and the magneto-optical recording medium satisfies conditions Tc2<Tcomp1<Tc1 and Tc2<Tcomp1<Tc3 where Tcomp1 is a compensation temperature of the first magnetic layer, Tc1, Tc2 and Tc3 are Curie temperatures of the first, second and third magnetic layers, respectively.

Abstract: A complex of a dye cation and an anionic TCNQ derivative of the formula (I): 1

Abstract: Initialization nonuniformity due to interference of light which occurs during an initialization process is reduced without causing degradation in the characteristic of signals recorded/reproduced on/from respective recording layers. A multilayer optical disk comprising at least a first information recording layer and a second information recording layer formed, on a substrate, into a multilayer structure with an intermediate layer disposed therebetween is illuminated with initializing light from the side of the first information recording layer to initialize the first information recording layer formed of a phase-change material serving as a recording material.

Abstract: An optical recording medium having a laminated structure portion (4) including a light-emission layer (3) and a recording layer (2). The light-emission layer (3) is made of a light-emission material excited by reproducing laser light to emit fluorescent light, and the recording layer (2) is made of a material in which at least a refractive index or an absorption coefficient can be changed relative to light emitted from the light-emission layer by recording laser light. The recording layer (2) is disposed to be closer to a side into which reproducing laser light is introduced than the light-emission layer (3). Then, recorded information recorded on the recording layer by the change of the refractive index or the absorption coefficient is read out from the recording layer as the change of intensity of light emitted from the light-emission layer (3) when it is irradiated with reproducing laser light.

Abstract: In the multi-layer information medium having a plurality of information-storing layers according to the present invention, distance between the adjacent information-storing layers is reduced with no increase in cross talk between these layers. The optical information medium has at least two information-storing layers each storing recorded information and/or servo information, and at least one of the information-storing layers is recorded or read by the recording beam or the reading beam which has passed through other information-storing layer(s). The medium has a filter layer between the adjacent information-storing layers, and in the spectral absorption characteristics in the wavelength range of 300 to 1000 nm of this filter layer, a wavelength range exhibiting an absorption of 80% or higher and a wavelength range exhibiting an absorption of 20% or lower are present.

Abstract: An optical disc having machine-readable, information-encoding features is provided with a barrier layer secured to the disc. This barrier layer is configured to prevent machine-reading of the features. A reading-inhibit agent, included in the disc and activated by removal of the barrier layer, is operative, once activated, to alter the disc to inhibit reading of the disc Alternately, the barrier layer can be eliminated, and the reading-inhibit agent can be activated by initial reading of the disc, as for example by exposure to optical radiation associated with reading of the disc, or rotation of the disc.

Abstract: An optical disk from which recorded data are read out by means of light irradiation has a substrate having recording pits as data on a surface thereof, and stacked films formed on the substrate. The stacked films contain a super-resolution film of a polymer matrix and semiconductor particles having an organic group covalently bonded thereto, and a reflective film reflecting light. The super-resolution film and the reflective film are provided in this order from a light incident side.

Abstract: An optical disc in which two optical discs are laminated together to realize high recording density and improved recording/reproducing characteristics for information signals, and a manufacturing method for the optical disc. When laminating a first disc having a first information recording portion on one surface of a first substrate to a second disc having a second information recording portion on one surface of a second substrate, the direction of warping of the first disc is set so as to be opposite to the direction of warping of the second disc, and the first disc is laminated to the second disc so that the surface of the first substrate having the first information recording surface will face the surface of the second substrate carrying the second information recording portion.

Abstract: An optical data storage system and method comprising a photopolymer medium having generally a polymerizable monomer, an active binder, a first, hologram recording polymerization initiator, and a second, data writing polymerization initiator. The monomer is preferably a cationic ring-opening monomer. The hologram recording polymerization initiator preferably comprises a sensitizer and photoacid generator which initiate a first polymerization in the medium which defines a format hologram. The format hologram recording is carried out via interference of a signal and reference beam, with the sensitizer being specific for the wavelength(s) of the signal and reference beams. The hologram recording polymerization is only partial and does not consume all of the monomer present in the photopolymer medium.

Abstract: A program area for the normal writing of information is provided on a first side of an information recording and reproducing medium, and a label area and a program area on which information can be written are provided on the opposing second side of the medium. A bibliographic description such as the name or trademark or the like of the company who manufactured the disc is recorded in the label area using printing or the like. A recording layer of a cyanine or an azo based organic dye is provided in the program area, and an image pattern is recorded optically onto this recording layer. With such a construction, a user can form a visible pattern known as pit art on the recording layer of the program area by optically writing a desired image pattern, and as a result can readily identify and organize a plurality of information recording and reproducing media.

Abstract: The invention includes a method of manufacturing a fluorescent 3-D optical memory device implementing an active medium capable of storing information at high information density, and an optical memory device manufactured by this method. The active medium employed in the present invention is a material capable of existing in at least 2 isomeric forms. Transition from one form to another can be induced upon illuminating this material by a “writing” electromagnetic radiation having a first spectrum. At the same time the other isomeric form is capable of fluorescence upon illuminating this material by a “reading” electromagnetic radiation with a second spectrum. By virtue of illuminating with a radiation having the first spectrum there are created elemental cells within a medium material, containing substantially the same isomeric form thereof, which can be either that form which is capable of fluorescence or the other one which is not.

Abstract: Disclosed is an optical recording medium, including a substrate, a reflective film on the substrate, a super resolution film made of an optical material whose complex refractive index is changed in accordance with an intensity of a light irradiating the super resolution film, a first thin film interference section constituted by plural transparent thin films, the plural transparent thin films being stacked one another, each two of the plural transparent thin films adjacent to each other being different from each other in refractive index, and the super resolution film and the first thin film interference section forming a laminate structure between the substrate and the reflective film or on the reflective film, and a recording film optionally provided between the laminate structure and the reflective film. Also disclosed is a recording-reproducing apparatus having such a medium.

Abstract: A user-removable optical data storage system is provided. A rotatable first-surface medium is enveloped in a cartridge. The cartridge provides relatively large data capacity such as about 0.25 Gbytes or more despite a relatively small size such as about 35 mm×35 mm×3 mm. Preferably the cartridge substantially seals the data surfaces of the medium when the cartridge is withdrawn from a drive and at least a portion of one surface is automatically exposed to the objective of an optics arm when said cartridge is inserted in the drive. Tracking involves rotating an optic arm about an axis parallel to the disk rotation axis. Focus can involve pivoting the arm about an axis parallel to the disk surface.

Abstract: An information recording medium and a supporter used for the information recording medium capable of recording a land/groove recording by using a high density recording technique such as a super-resolution, resulting in a high density recording. An information recording medium B has a supporter 1A, on which a recording layer 5 is formed. On the supporter 1A, lands 2 and groove 3 are alternately formed as a minute track pattern. A crevice 4 having a depth Dc larger than a depth Dg of the respective grooves 3 is formed in the respective grooves 3 at one end of the respective grooves 3 in a width direction of the respective grooves.

Abstract: A high-density optical disk comprises a transparent substrate having a guide groove having a depth of 100 to 200 nm, width of 0.2 to 0.4 &mgr;m arranged with a track pitch of 0.7 to 1.0 &mgr;m. A recording layer is made of an organic pigment exhibiting a specific main weight reduction in a thermogravimetric analysis and a specific exothermic peak in a differential thermal analysis.

Abstract: A perishable media information storage mechanism, including a substrate, a data layer for recording data thereon the information storage mechanism, a reflective layer, and a protective lacquer coating. The data layer includes a material responsive to at least one predetermined data elimination factor and includes one of a decayable dye material, a liquid crystal material, a photosensitive material or a plurality of magnetoresistive memory cells. The data layer is characterized as recording data and eliminating access to data in response to at least one of a predetermined use or time factor. In addition, included is a method for fabricating a perishable media information storage mechanism including the steps of providing a substrate, forming a data layer on a surface of the substrate, forming a reflective layer on an uppermost surface of the data layer, and forming a protective coating on an uppermost surface of the reflective layer.

Abstract: A method and apparatus for reading from and writing to a magneto-optical disc. The apparatus comprises a first objective lens situated between a first side of the magneto-optical disc and a first source of a laser light. The apparatus further comprises a first flying magnetic head situated between the first objective lens and the first side of the magneto-optical disc, including a first coil for supplying a first magnetic field, the first coil defining a light channel through the first flying magnetic head for allowing the laser light to reach the magneto-optical disc.

Abstract: A metallized azo-ether dye comprising an azo group linking a substituted 3-hydroxy-pyridine nucleus to a phenyl nucleus wherein the phenyl nucleus has an alkoxy or thioether substituent at its 2-position. The dye is useful in the recording layers of optical recording elements.

Abstract: A storage medium has at least one diffraction grating. The diffraction grating is formed as a holographic interference fringe pattern. The pattern is formed as it two-dimensionally diffracts an incident light beam in a plurality of directions or one-dimensionally diffracts an incident light beam in a direction. A combination of such patterns and also a plurality of rows of such patterns on the storage medium are available. A light beam is radiated to the storage medium. The light beam diffracted in the direction(s) is detected by a photodetector, such as a CCD device, that generates a signal carrying data stored as the holographic interference fringe pattern. The signal is then decoded by a processor to reproduce the data.

Abstract: This invention is characterized in that information is recorded by injecting electric charge into a charge holding region made from a donor or acceptor, and the recorded information is reproduced by using changes in luminescence characteristics of the luminescent material contained in the charge holding region or a light emitting region formed near the charge holding region, that occur in accordance with the charge condition of the charge holding region.

Abstract: The present application discloses a laser ablative recording material which has one or more image forming layers on a support, and one or more intermediate layers between said image forming layer and said support, wherein:at least one layer from among the layers on the image forming layer side contains a substance having absorption in the laser wavelengths, which is selected from dihydroperimidine-squarilium dyes represented by the following general formula (1): ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7 and R.sub.8 independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted aryl group; and R.sub.1 and R.sub.2, R.sub.3 and R.sub.4, R.sub.5 and R.sub.6, R.sub.7 and R.sub.8, R.sub.2 and R.sub.3 and/or R.sub.6 and R.sub.7 may be taken together to form 5 to 6 membered rings.

Abstract: An optical recording medium comprising a substrate having a pre-groove for focusing and tracking servo operation, and a recording film formed on the substrate, the recording film having optical properties which change in response to the application of at least one of a light beam or heat to a portion of the recording film.

Abstract: The optical storage device and method includes a fluorescent layer arranged on a substrate and having a surface. The fluorescent layer is composed of fluorescent dye molecules embedded in a transparent polymeric base material. A group of data-carrying structures are arranged in the fluorescent layer. Each of the data-carrying structures has more than two optical states represented by a specific degree of quenching of fluorescence emitted from the data-carrying structure when irradiated with a fluorescence exciting radiation.

Abstract: An optical storage system suitable for optical storage and retrieval of information using a storage medium comprising a substrate, an active layer for retention of the data, and an overlying optical layer, or layers for double-sided. The optical layer serves to produce an evanescent field in or adjacent to the active layer in response to an incident beam of radiation. The evanescent field is frustrated or attenuated by the data in the active layer and produces a signal.

Abstract: The invention includes a method of manufacturing a fluorescent 3-D optical memory device implementing an active medium capable of storing information at high information density, and an optical memory device manufactured by this method. The active medium employed in the present invention is a material capable of existing in at least 2 isomeric forms. Transition from one form to another can be induced upon illuminating this material by a "writing" electromagnetic radiation having a first spectrum. At the same time the other isomeric form is capable of fluorescence upon illuminating this material by a "reading" electromagnetic radiation with a second spectrum. By virtue of illuminating with a radiation having the first spectrum there are created elemental cells within a medium material, containing substantially the same isomeric form thereof, which can be either that form which is capable of fluorescence or the other one which is not.

Abstract: A magneto-optical recording medium adapted for reproduction of a high resolution signal without the necessity of a reproducing magnetic field. The magneto-optical recording medium comprises a transparent substrate and deposits of a reproducing layer, a switch layer and a recording layer formed on the transparent substrate successively. The reproducing layer is a perpendicular magnetization film at a room temperature but is turned to an in-plane magnetization film when heated beyond a predetermined temperature. Each of the switch layer and the recording layer is a perpendicular magnetization film. The respective Curie temperatures Tc1, Tc2 and Tc3 of the reproducing layer, the switch layer and the recording layer satisfy the relationship of Tc1>Tc3>Tc2.

Abstract: An optical recording medium has a phase-change recording layer embedded in a stack of thin layers arranged on a substrate. At least one of the dielectric layers adjacent to the recording layer comprises a carbide. The carbide layer is separated from the substrate and/or from a reflecting layer in the stack by a dielectric layer not containing a carbide. The thickness of the carbide layer either lies in a range from 2 to 8 nm or is substantially equal to the thickness of the adjacent dielectric layer.

Abstract: The invention features an apparatus and method for reproducing recorded bits from a magneto-optical recording medium. The medium includes a base, a readout layer formed on the base, a transfer layer formed on the readout layer and a recording layer formed on the transfer layer. The readout and recording layers each exhibit perpendicular magnetization in a temperature range between room temperature and, respectively, the readout layer's Curie temperature and the recording layer's Curie temperature. The transfer layer is predominant in-plane magnetization at room temperature and an in-plane to perpendicular magnetization transition occurs at a temperature above room temperature. Also, the recording layer Curie temperature is lower than the Curie temperature of the transfer layer. The reproducing method includes the steps of projecting a light beam, applying a subsidiary magnetic field and reproducing information based on reflected light from the readout layer while applying the subsidiary magnetic field.

Abstract: An information memory apparatus includes an information storage medium having a thin film formed as a recording layer or a superresolution reading mask layer on a substrate directly or via a foundation layer to record and/or reproduce information stored in the form of an atom configuration change caused by irradiation of an energy beam. The information storage medium includes reflective layers as well. The information memory apparatus further includes a laser used for at least recording. The laser has a wavelength. The light absorptance of the recording layer or mask layer of the medium in a crystalline state at the wavelength is greater than or equal to the light absorptance of the recording layer or mask layer of the medium in an amorphous state at the wavelength.

Abstract: A method of coating an optical recording layer on a transparent grooved substrate is disclosed. The recording layer is coated from a mixture of a primary and a secondary solvent. The solvent mixture provides a wide range of conformalities for optical recording layers.

Abstract: An optical recording medium having at least a recording layer and a reflective layer on a substrate. The recording layer contains a dipyrromethene metal chelate compound obtained from a dipyrromethene compound represented by the general formula (1) and a metal ion: ##STR1## wherein R.sup.1 to R.sup.7 are defined in the specification.