Dye for optical recording medium

Details Dye for optical recording medium Dye for optical recording medium

2002-09-17

2004-02-10

Powers, Fiona T. (Department: 1626)

Organic compounds -- part of the class 532-570 series

Organic compounds

Azo

C534S705000, C534S707000, C534S710000

Reexamination Certificate

active

06689872

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical recording medium. More particularly, the present invention relates to a dye for an optical recording medium.
2. Description of Related Art
Compact disk (CD) comprises the following advantageous qualities: high storage capacity, small volume, stability over long storage period, low production cost, high compatibility and low error rate. Compact disk thus becomes a major optical information recording medium. Amongst the various types of compact disk, the most popular is the Compact Disk-Recordable (CD-R), which is a recording medium capable of recording and retrieving information by means of a laser beam having a wavelength of 770 nm to 830 nm.
Through the popularization of multimedia, large amount of textual, sound and image data are generated. The original 650 MB capacity CD-R can no longer accommodate the audio-visual demand of the next generation. Therefore, the industry introduces a Digital Versatile Disc-Recordable (DVD-R) with a memory capacity several times of that of the CD-R. The Digital Versatile Disc-Recordable (DVD-R) has the capability for recording and retrieving information in a high density because semiconductor lasers having shorter wavelengths than that for the conventional CD-R (for example, lasers having wavelengths 620 nm to 690 nm) are used for recording and retrieving information. DVD-R is going to be a major optical information recording medium.
The write-once version of the DVD-R uses an organic dye as a recording layer. Recording is performed by irradiating a short-wavelength laser to the dye-based recording layer. Upon the absorption of the laser beam energy, the irradiated portion of the recording layer will undergo a thermal deformation. This basically forms a pit that represents the digital bit being recorded. The most commonly used organic dye includes cyanine dye, azo dye, benzofuryl ketone dye, indigo dye, etc. However, using the above dyes as a recording layer for an optical recording medium, there is a problem of poor optical stability. Especially the short wavelength laser is used to perform the recording/reproduction, the stability of the stored data, the reflection rate and photosensitivity will be adversely affected. Normally, the above dyes are incorporated with the various organic dye metal chelate compound to improve the photo stability.
A conventional optical recording medium dye, as disclosed in U.S. Pat. No. 5,330,542, includes an azo metal chelate compound comprising an azo type compound of the following structure (I):
wherein, x is a group having an active hydrogen; A is a residue forming a benzene ring derivative, for example, benzene, naphthalene, etc., together with two carbon atoms; and B is a residue forming a benzene ring derivative or a heterocyclic ring derivative, for example, benzene, naphthalene, thiazole, benzothiazole, pyridine, quinoline, pyridobenzothizole, pyrazole, etc., together with a carbon atom and a nitrogen atom.
Another conventional optical recording medium dye, as disclosed in U.S. Pat. No. 6,225,023, includes an azo metal chelate compound comprising an azo type compound of the following structure (II) or (III):
or
wherein each of A
1
and A
2
is a residue forming a benzene ring derivative or a heterocyclic ring derivative together with two carbon atoms. The heterocyclic ring derivative includes, for example, benzene, naphthalene, pyridine, etc.; each of B
1
and B
2
is a residue forming together with the carbon atom and the nitrogen atom to form a heterocyclic ring derivative, for example, benzene, naphthalene, thiazole, benzothiazole, pyridine, quinoline, pyridobenzothizole, pyrazole ring, etc.; Y is a C
1-6
linear or branched alkyl group.
The above azo type of dye is formed by having the nitrogen on the heterocyclic ring and the active group on the benzene ring to chelate with the metal. It is therefore necessary to introduce an active group to the benzene ring. An introduction of an active group to the azo compound normally requires other coupling processes.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides an optical recording medium dye. The dye of the present invention is an azo metal chelate compound, wherein the nitrogen atom on the heterocyclic ring of the azo compound directly chelates with the metal. An introduction of an active group is precluded.
The present invention further provides an optical recording medium dye wherein the optical stability of this material is favorable. Further, the material is applicable as a data layer of an optical recording medium in which short wavelength laser can use for recording or reproduction.
In accordance to the present invention, an optical recording medium dye is provided, wherein this optical recording medium dye is an azo metal chelate compound. This azo metal chelate compound comprises an azo type compound of the following structure (IV):
wherein A
3
and B
3
are residues forming a heterocyclic ring derivative together with the carbon atom and the nitrogen atom. The heterocyclic ring derivative includes derivatives of an imidazole group, a thiazole group, an oxazole group, a benzothiazole group, a benzopyridoxinethiazol group, a pyridoxinethiazole group, a pyridine group, a pyridazine group, a pyrimidine group, a pyrazine group, a triazine group, a quionline group, a pyridobenzothiazole group, a pyrazole group, or the above heterocyclic ring derivatives that contain the following substituent: a halogen atom, a nitro group, a cyano group, an amino group, a formyl group, a hydroxyl group, a carboxyl group, an alkylamino group, a substituted C
1-15
straight chain alkyl group, an unsubstituted C
1-15
straight chain alkyl group, a branched alkyl group, a cycloalkyl group, an alkoxy group, an alkyl carbonyl group, a straight chain alkenyl group, a branched alkenyl group, a cylcoalkenyl group, a hydroxyalkyl group, an alkoxycarbonyl group, an alkoxycarbonylallyl group, an alkylthio group, an alkylsulfonyl group, an aryl group or a heterocyclic group.
If the
part of the above structure (IV) is, for example,
a pyridine derivative, the above azo compound structure (V) can be represented as follow:
wherein R
1
is, for example, a hydrogen atom, a C
1-6
straight chain or branched alkyl group, an amino group, an alkylamino group or a tolylamino group; R
2
is, for example, a hydrogen atom, a hydroxyl group, a halogen group, an ether group, an ester group or a C
1-6
straight chain or branched alkyl group; R
3
is a hydrogen atom, a C
1-6
straight chain or branched alkyl group; R
4
is, for example, a hydrogen atom, a C
1-6
straight chain or branched alkyl group or a halogen atom; A
3
is a residue forming a heterocyclic ring derivative together with the carbon atom and the nitrogen atom.
The above heterocyclic ring derivative includes derivatives of an imidazole group, pyrazole group, a triazole group, a tetrazole group, a benzoimidazole group, a thiazole group, an isothiazole group, a thiadiazole group, a thiatriazole group, a benzothiazole group, an oxazole group, an isoxazole group, an oxadiazole group, an oxatriazole group, a benzoxazole group, etc.
Thus, the
part of the above structure (V) includes, for example,
wherein the substituent E
1
to E
38
each includes, for example, a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amino group, a formyl group, a hydroxyl group, a carboxyl group, an alkylamino group, a substituted or unsubstituted C
1-15
straight chain alkyl group, a branched alkyl group, a cycloalkyl group, an alkoxy group, an alkyl carbonyl group, a straight chain alkenyl group, a branched alkenyl group, a cycloalkenyl group, a hydroxyalkyl group, an alkoxycarbonyl group, an alkoxycarbonylallyl group, an alkylthio group, an alkylsulfonyl group, an aryl group or a heterocyclic group.
The metal ion for forming the azo metal chelate compound includes nickel, cobalt, iron, ruthenium, rhodium, palladium, copper, iridium, platinum, zinc, etc.
The optical recording medium dye of the present invention is an a

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