GB2193659A

GB2193659A - Optical information recording medium

Info

Publication number: GB2193659A
Application number: GB8717802A
Authority: GB
Inventors: Tsutomu Satoh; Tatsuya Eida; Keiko Ichinose
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1986-07-28
Filing date: 1987-07-28
Publication date: 1988-02-17
Anticipated expiration: 2007-07-28
Also published as: GB2193659B; DE3724981C2; GB8717802D0; DE3724981A1

Description

GB2193659A 1

SPECIFICATION

Optical information recording medium The present invention relates to an optical information recording medium suitable for writing or 5 reproducing information or data therein by means of laser beams, particularly semi-conductor laser beams. More particularly the invention relates to an optical information recording medium having a thin organic recording layer containing as main components a polymethine dye and certain particular salts derived from organic cations and metal complex anions.

There is known information recording and reproduction apparatus for recording and reproduc- 10 ing information by projecting laser beams onto a rotating disc-shaped recording medium. As a recording medium for use with such information recording apparatus, there has been proposed a recording medium comprising a substrate having a recording layer formed thereon which layer comprises a metal having a low melting point, or such a metal together with a dielectric material. Such a recording medium, however, has the shortcomings that the preservability is 15 poor, the image resolution power is low, the recording density is low, and the cost is high.

We have previously proposed an optical information recording medium comprising a substrate bearing a thin organic recording layer containing, as main component, a polymethine dye. This recording medium has improved writing sensitivity, reflection ration and S/N ratio for reading as compared with other conventional optical information recording media. However, it still has the 20 shortcomings that the stability to light and heat, and the durability to the reproduction light may be insufficient for use in practice.

It is an object of the present invention to provide an optical information recording medium which has improved light resistance, heat resistance and durability in the course of the reproduc tion of recorded information. 25 According to the invention there is provided an optical information recording medium compris ing a substrate bearing a thin organic recording layer containing, as main components, a polym ethine dye and a particular salt compound derived from (i) an organic cation (A) of formula (A-1), (A-11) or (A-111) given below, and (5) a metal complex anion (B) preferably of any one of formulae (13-1) to (B-Vill) given below. 30 Cations of formula (AA) are of the formula:

[Z=N = A-N ', R 1] M+ (A-1) 35 R 2 40 0 in which Z represents a group t= which may be substituted with a C,-C, alkyl or C,-C, alkoxy group or a group 45 R is -CO-N R 16 50 (wherein R" and R16 are each hydrogen, a C,-C, alkyl group or a phenyl group), or the phenyl group in the group Z may form a condensed aromatic ring; R' and R2 are each a C,-C,, alkyl group or a phenyl group (which may be substituted with halogen, a Cl-C6 alkyl group, a Cl-C6 alkoxyl group or a di[C1-C6 alkyll amino group; m is 1 or 2; and 55 A is a group: - n 60 (in which n is 1 or 2 and which may be substituted with a halogen, a Cl-C, alkyl group, a Cl-C, alkoxy group or a hydroxyl group), or, when m is 2, a group 2 GB2193659A 2 Cations of formula (A-11) have the formula:

5 R 3 R 5 Me N-@2 N-A-N-O-N,, R 6 10 in which R3, R4, R5 and R6 are each hydrogen or a Cl-C, alkyl group (which may be substituted) and A and m have the meanings defined above.

Cations of formula (A-111) have the formula:

15 X 0 N X (0 Y 20 in which X is (i) a phenyl group, which may be substituted with a C,-C, alkyl group, a C,-C, alkoxy group, a Cl-C6 alkylthio group, a halogen atom or a hydroxyl group; (ii) a cyclohexylamino group; (iii) a benzylamino group, the phenyl moiety of which may be substituted with a C,-C6 25 alkoxyl group, a C,-C, alkylthio group, a halogen atom or a hydroxyl group; or (iv) a di-[C1-CJ alkyll amino group; and Y has the same meaning as X or is hydrogen or is as defined for the substituents on X when it is a phenyl group.

Anions of formula B-1 have the formula:

e 30 R2 0 5,m/s 0 - I) (B R3 S R 3 R 4 R 4 35 in which W, R2, W and R4 are each a hydrogen or halogen atom, a C,-C6 alkyl group (which may be a substituted with a hydroxyl or C,-C, alkoxyl group), a C,-C, alkoxy group, an amino group (which may be substituted with a C,-C, alkyl group) or a benzyl group; and M is Ni, Co, Mn, Cu, Pcl or Pt. 40 Anions of formula (B-11) are:

RS S S Ri-e 11 11 (B - 11) 45 _ R 61" C S R8_ in which each of Rs, R6, R 7 and W' is a C,-C, alkyl group (which may be substituted with halogen or a hydroxyl or a C,-C, alkoxy group), an aryl group (which may be substituted with 50 halogen, a Cl-C4 alkyl or alkoxy group, or a cyano, nitro or amino group), an amino group (which may be substituted with a C,-C, alkyl group), a benzyl group, or a cyano group; and M has the meaning defined above.

Anions of formulae (B-111), (BAV) and (B-V) have the formulae:

3 GB2193659A 3 R' R' R 24:t 5 5 R2 R 3 0 0 5 m,'S 00 R3 0-111) 5 R R 4 10 R2 5 m R 2 (B - iv) R 3 0 0 0 0 R 3 - 4 R 4 15 20 3 R 2 3- e R R,R R 0 4 (B-V) 25 0 0 11.1 m 1.1 0 10 1 in which W, R2, R3 and R4 and M have the meanings defined above. 30 Anions of formula B-(V1) have the formula:

[NC S 1-1 m 1-1 S R9]e. (B - V1) -)'r --, -, 5:( 10 35 NC 'S in which R9 and RIO are each hydrogen, a cyano group, a C,-C, alkyl group (which may be substituted with a hydroxyl or C,-C, alkoxy group) or an aryl group (which may be substituted with halogen, a C,-C, alkyl or alkoxy group, or a hydroxyl, cyano, nitro or amino group); and M 40 is Ni, Co, Mn, Cu, Pcl or Pt.

Anions of formula B-Vil have the formula:

W1 -e W2 0 S 1 m S 1 R 9 (B-VR) 45 3 S S 14 50 in which R9 and RIO and M have the meanings defined above; and R", R12, R13 and R14 are each hydrogen or halogen or a cyano or hydroxyl group; and the phenyl group in the formula may form a condensed aromatic ring.

Anions of formula B-Vill have the formula:

55 R 12 N S,,, K S.( R 9 (B - VIII) 3 N 5 5, R10 - 4 60 0 in which W, RIO, R", R12, R13, R14 and M have the meanings defined above.

Specific examples of cations of formula (A-1) are as follows:

4 GB2193659A 4 A-I-1 0= 0 =N N ",_N(CH3)2 (D 5 L, co \@-N(CH3)2 1 NH 1 CH3 10 1 - (D A-i2 0 0 =N 1/ C2H5 15 - 'C2H5 COHN 20 25 0 (D A-I-3 C3H7 30 C3H7 35 OCH3 40 A-1-4. 0 0 N(CH3)2 0= 8 =N -N /C_ \\oN(CH3)2 45 GB2193659A 5 N(CHI A-1-5 0 CH3 C3H7 5 C3H7 10 0 C2Hs 15 A-1-6 - C2Hs CONH 20 N(CHI 25 - - (D A-I-7 C2 /,N(C2H5)2 30 N(C 2 H 5) 2 6 GB2193659A 6 0 CH3 - - E) A-1-8 0= =N N,_N(CH2 0 N(CH3)2 5 0 CONH 10 1 - (D 15 A-I-9 0 OCH3 N(C4H02 -N N(C4N2 CONH-CH3 20 25 0 CH3 - (D A-1-10 0= N o N CA 30 - j - C2H5 CONH-C 7 GB2193659A 7 - (D A-1-11 0= 0 N OCH3 N "_N(C4H9)2 L "'N(C4H9)2 _i 5 10 - CsHil - (D A-1-12 = 0 =N N /'C 15 L_ () 8 -@-,,,,no - 20 0 25 A-I-13 0- - =N-,N(C6H13)2 CONH 30 - 0C6Hn - E) 35 A-1-14. 0- 0 N-oN /C-N(C6Hi3)2 40 \oN(C6H13)2 45 - (D 0 50 A-1-15 0= _ N-N(C2Hs)2 co L 1 55 N(C6H13)2 8 GB2193659A 8 Specific examples of cations of formula (A-11) are as follows:

A-II-1 (C2H512N-C-2-N-NO--(-C-N(C2H5)2)21 5 A-II-2 [((CH3)2N--2 N-&NT--N(CH3)2)2] 10 A-11-3 [((CH3)2N-.2 N(D=(0NT--N(CH3)2)21 15 A-II-4 [((C2H5)2N-N=(0 -NT--N(C2H5)2)21 20 2 (D 25 A-11-5 [((C3H7)2N-N=.NI---N(C3H7)2)21 2 30 A-II-6 [((n-C3H7)2N--N-NT-(-N(n-C3H7)2)21 35 A-II-7 [(i-C3H7)2N-N-@-M@---@-N(i-C3H7)2)21 40 A-I-I-8 [((n-C4H9)2N--2 N-NT--N(n-C4H9)2)21 45 A-11-9 [((CH3)2N-C-2- N --NO---N(CH3)2] 50 A-II-10 [((C2H5) 2 N-C-2-N-N(51--N(C2Hs)2)21 55 A-II-11 (C31711) 2 N -C-hN-N'T--N(C3H7)2)21 60 Specific examples of cations of formula (A-111) are listed below:

9 GB2193659A 9 Position Cation X of Y Y 5 A-11-1 phenyl 4 phenyl A-111-2 3-bromophenyl 4 3-bromophenyl A-111-3 4-chlorophenyl 4 4-chlorophenyl A-111-4 4-methyoxyphenyl 4 4-methoxyphenyl A-111-5 cyclohexylamino 4 cyclohexylamino 10 A-111-6 dibenzylamino 4 dibenzy[amino A-111-7 di-[3'-bromo- 4 di[X-bromobenzyll benzyilamino amino A-111-8 diethylamino 4 diethylamino A-111-9 diethylamino 4 hydroxyl 15 A-111-10 diethylamino 2 methyoxy A-111-1 1 diethylamino 3 chloro A-111-12 diethylamino 2,4 dimethoxy A-111-13 dimethylamino 4 methylthic, A-111-14 dimethylamino 3 methoxy 20 A-111-15 dipropylamino - H A-111-16 dipropylamino 3 fluoro A-111-17 diethylamino 3,4 dimethoxy A-111-18 diethylamino 3 hydroxy A-111-19 diethylamino 3 methylthio 25 A-111-20 4'-methylphenyl 4 4'methylphenyl A-111-21 phenyl 4 4'-diethylamino phenyl A-111-22 dibenzylamino 4 dibutylamino 30 Specific examples of the metal complex anions of formulae (13-1) to (13- VIII) are as follows:

GB2193659A 10 Formula (B-I) 5 Anion R 1 R 2 R 3 R 4 m 10 B-I-I cl cl H cl Ni.

B-I-2 H N(CH 3)2 CH 3 H Ni B-I-3 H H H H Pd 15 20 Formula (B-II) 25 Anion R R 2 R 3 R 4 m 30 B-II-1 Ph(Phenyl) Ph Ph Ph Ni 35 B-II-2 PhN(CH 3)2 Ph Ph PhN(CH 3)2 Ni B-II-3 PhN(C 2 H 5)2 PhN(C 2 H 5)2 PhN(C 2 H 5)2 PhN(C 2 H 5)2 Ni 40 B-II-4 PhN(C 2 H 5)2 Ph PhN(C 2 H 5)2 Ph Pt 45 Formula (B-III) 50 Anion R R 2 R 3 R 4 m 55 B-JJ1-1 H H H H NI 60 B-III-2 H cl. cl H Ni B-III-3 H Br H H 65 Ni GB2193659A 11 iFormula (B-M R 2 R 3 R m 5 Anion R B-IV-1 H N(CH 3)2 CH 3 H Ni B-1V-2. cl cl H cl Ni 10 B-IV-3 Br Br H Ni 15 Formula (B-V) 20 R 2 R R m Anion R 25 B H N(CH 3)2 H H -V-1 Ni 30 B-V-2 H H H H Ni B-V-3 H CH H H 35 3 Pt Formula (B-VII) 40 Anion R 9 R 10 m 45 B-VI-I H phenyl Ni B-VI-2 cyano cyano Ni 50 B-VI-3 phenyl phenyl Ni B-VI-4 c-diethylaminophenyl =R 9 Ni 55 B-VI-S 41-methoxyphenyl =R 9 Ni B-VI-6 cyano cyano. Pt 60 B-VI-7 phenyl phenyl Pd 12 GB2193659A 12 Formula (B-VII) Anion R 9 R 10 R 11 R 12 R 13 R 14 m B-VII-1 H H H H H H Ni 10 B-V112 H phenyl H_ -CH 3 H H Ni ' B-V11-3 -M -W H H H H Ni 15 B-WII-4 -M -M cl cl H cl Ni B-VII-5 phenyl =R 9 H H H H Ni B-VII-6 4-diethylamino phenyl =R 9 H H H H Ni B-VII-7 4-methoxy- 9 25 phenyl =R cl H cl H Ni B-VII-8 phenyl =R 9 H CL H H Pd B-VII-9 -W -W H H H H pi 30 B-VII-10 -W -CH H -CH=CH-CH=CH- H Ni B-VII-11 phenyl =R 9 H -CH=CH-C=CH- H Ni 35 Formula (B-VIII) 40 Anion R 9 R 10 R 11 R 12 R 13 R 14 m 45 B-VIII-1 phenyl =R 9 H H H H Ni 0 B-VIII-2 phenyl =R9 H cl H H cl 50 B-VIII-3 4-dimethyl- phen 1 9 H H H H Ni =R B-VIII-4 phenyl =R 9 cl cl H cl Ni 55 B-VIII-5 -M -M H H H H Ni B-VIII-6 -W -W H cl H H Ni 13 GB2193659A 13 Anion R 9 R 10 R 11 R 12 R 13 R 14 M B-VIII-7 -CN -CN C1 C1 H C1 Pd B-VIII-8 phenyl =R 9 H H H H Pd 1OB-VIII-9 phenyl =R 9 H C1 H H Pt 10 B-Vlll-10 4-diethyl- amino phenyl =R 9 H H H H Ni 15 B-V111-11 phenyl phenyl H -CH=CH-CH=CH- H Ni The salts of the organic cations and metal complex- anions can be prepared (1) by methods utilizing solubilizing differences or (2) by methods utilizing an ion exchange resin, as described 20 below.

1. Methods Utilizing Solubility Differences (a) Crystallization of the desired salt A solution of a compound consisting of a cation of any of formulae A-1 - A-111 and a counter 25 ion is mixed with a solution of a compound consisting of a metal complex anion of any of formulae 13-1-13-VIII and a counter ion, so that the desired salt consisting of the cation and the metal complex anion crystallizes out. In this case, the mixed solution can be condensed or cooled. It is preferable that the counter ions have a high solubility in the solution. As the solvent, there is preferably employed a single solvent in which the salt is slightly soluble, but in 30 which the counter ions are highly soluble. In order to promote crystallization of the desired sa It, other salts can be added to the mixed solution to effect salting-out of the desired salt.

(b) Crystallization of bout counter ions In contrast to the method (a), the two counter ions are combined and crystallized, so that the 35 remaining cation and the metal complex anion are caused to precipitate in the form of the desired salt. In this case, it is preferable to employ a single solvent in which the salt is highly soluble, but the counter ions are slightly soluble. In order to promote the crystallization of the two counter ions, other salts can be added to the mixed solution to effect salting-out of the salt of the two counter-ions. 40 2. Methods Utilizing Ion Exchange Resins (a) Preparation of the desired salt using a cation exchange resin The cation is absorbed by a cation exchange resin The cation exchange resin is then passed through a solution of a metal complex, whereby the desired salt is obtained. 45 (b) Preparation of the desired salt using an ion exchange resin The metal complex anion is absorbed by an anion exchange resin. The anion exchange resin is then passed through a solution of the cation, whereby the desired salt is obtained.

An optical information recording medium according to the present invention comprises a 50 substrate having a recording layer formed thereon. When necessary, an intermediate layer, for instance an undercoat layer, can be interposed between the substrate and the recording layer.

Furthermore, a protective layer can be formed on the recording layer. Furthermore, by using a pair of such optical information recording media, air-sandwich type and close-contact sandwich type optical information recording media can be constructed, as will be discussed later. 55 It is preferable that the specified salt be present in the recording layer in an amount of from 2 to 60 wt.%, more preferably from 5 to 40 wt.%, based on the weight of the solids in the recording layer. It is also preferable that the salt be present in an undercoat layer, in a protective layer or in both layers in an amount of from 2 to 100 wt.%, more preferably 20 to 100 wt.%, based on the weight of solids in each layer. 60 With regard to the substrate of the recording medium, only when recording and reproduction of information are performed on the substrate side, it is necessary that the substrate be transparent to the laser beams employed.

When the recording and reproduction are to be performed on the recording layer side, the substrate need not be transparent to laser beams. 65 14 GB2193659A 14 Suitable materials for the substrate include plastics such as polyesters, acrylic resins, polyam- ides, polyoldein resins, phenolic resins, epoxy resins and polyimides; glass; ceramics and metals.

On the surface of the substrate, there can be formed preformats for address signals, and pregrooves servicing as guide grooves.

The recording layer can record information by optical changes in the layer, which are caused 5 by the recording layer being exposed to laser beams. The recording layer comprises as its main components a polymethine dye (as discussed in detail below) and any of the above-described salt compounds. Representative examples of suitable polymethine dyes are cyanine dyes, mero cyanine dyes, croconium dyes and pyryliurn dyes.

In order to improve the recording characteristics and stability of the recording layer, two or 10 more dyes can be employed in combination. Furthermore, in addition to the above dyestuffs, the following dyes can be employed, namely: Phthalocyanine dyes, tetrahydrocholine dyes, dioxza zine dyes, triphenothiazine dyes, triphenothiazine dyes, phenanthrene dyes, anthraquinone (Inclan threne) dyes, xanthene dyes, tripheny1methane dyes, triphenylamine dyes and azulene dyes.

Metals such as In, Sn, Te, Bi, Al, Se, Ag and Cu, and metal compounds such as TeO, and 15 SnO can be dispersed in the recording layer or made into a layer formed on the recording layer.

Further, other polymeric materials, stabilizers (for example metal complexes and phenolic com pounds), dispersing agents, fire proofing agents, unguents, antistatic agents, and plasticizers can be added to the recording layer.

When the salt compound including an acid anion is present in the recording layer, it is 20 preferable that the ratio by weight of the polymethine dye to the salt compound be from 40:60 to 99:1, more preferably from 60:40 to 95:5.

The recording layer can be formed on the substrate by any of conventional method such as vacuum deposition, CVD (chemical vapour deposition) or solution coating. Of these methods, the solution coating method is most preferred. 25 When using a solution coating method, a polymethine dye and other components are dis- solved in an organic solvent (such as an alcohol, ketone, amide, ether, sulphoxide, ester, halogenated aliphatic hydrocarbon, or aromatic hydrocarbon). The resultant solution is coated onto a substrate by a conventional coating method, such as by spray coating, spin coating, dip coating, blade coating or'roller coating. 30 The thickness of the recording -layer is preferably from 100 A to 2000 A.

Representative polymethine dyes for use in the present invention include (a) cyanine dyes of the formulae:

RS 1 35 A C D N, (B. Y C=C-C= C C_ C=C C E B R4' 40 CA Z 45 - Y UD C= CC=C- C=C-C= I I 1 1 3 4 2 6 IRS R17 I R1 R R R E B 50 Z2 e"Z 40P C 04'f CH=CH4-nC= CH-C C- CH--tCH=CH.-C=4CH- CH=_NRW - Ya Z3, 55 Z2_' 60, \ E 60 R N-iCH=CHC=CH-CH=C-C=CH-fCH=CHil-C=ICH-CHiN-R -Ye I I" Ike R (IV) in which formulae A, B, D and E are each a substituted or unsubstituted aryl group; R1, R2, R3, 65 GB2193659A 15 R4, R5, R6, and R7 are the same or are different and each is a hydrogen or halogen atom or an alkyl group; Y together with the adjacent carbon atoms represents a five- or six-membered ring; R11 and R9 are the same or are different and each is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aralkyl group or alkenyl group; Z' and Z2 together with the adjacent carbon atoms each from a substituted or unsubstituted heterocyclic ring; Z3 together 5 with the adjacent carbon atoms forms a substituted or unsubstituted pentacyclic ring or hexacy clic ring, which may be condensed with an aromatic ring; RIO is a hydrogen or halogen atom; RII and R 12 are each a hydrogen or a halogen atoms, a hydroxyl group, a carboxyl group, an alkyl group, or a substituted or unsubstituted aryl group or an acryloxy group; and 1, m and n are each 0 or 1; and Y represents an acid anion. 10 Examples of cyanine dyes of formula 1, 11, 111 and IV are listed below.

Compound No. A B 1) E R 1 R 2 R 3 R 4 R 5 y XE) Formula (I)-1 C to 4 -2 11 cú C to 4 -3 R (CII -G (C" 3) 2 H H H H 11 C to -& 14 (CH 3) 2 4 3 2 -4 n No 2 11 11 U C 9,0 4 so 3-cp)- 3 p 6 R 7 Formula (11) It of It 11 11 H H H ct 11 H 01 G) - 1 4 0) M co a) z 2 -c-fctl-CH='-" -N-+CH=CII+C 3 a 9 to Compound No. z R R R P.

Formula (111) (ng MO93 c C113 cif 3 C11 3 11 0 1 ll NI S5 -2 JCO c 11 c 11 CL 0 CL H 00 4 9 4 9 n3C C" 3 113 H3 1-11 914 113c CH -4 If 3c CH H3C elf] c H c 11 11 -02y/ M-, et ro 2 5 2 5 ct, -5 c 2 11 5 c 2 11 5 11 1 1 OL m Li m 1 1 -6 c" H c 1 c 2 H 5 c 2 H 5 H ccl c H c H CL 1 1 -7 H3e P3 2 5 2 5 (gf,6 0 -8 14 3 c v 3 143 c 1 cII 3 II c 2 H 5 C2 H 5 H 1 503 -q elf] co- - J11 co, 0 -9 C11 3 CH 3 Dr 1 IS 0 4-C113 -10 c H c 11 11 1 so -c 11 (D n It 19 4 9 4 9 4 2 5 > j 00 .Z 2 -N-4C11=Cif 9 12 Compound No. --m - -nC _R R R R -9 - XO Formula (IV) 00 c 0 m 11 11 11 R 1 CL 1 C2 5 C2 5 3 c \.,C" H3e CH3 -2 cif cif H H CL 3 3 -3 @@ @Q c 5 11 7 C3 m 7 11 11 1 CL ?1 1 c" 3 cII 3 0 - 5 c H c 11 11 H CL 4 9 4 9 c) 0 W -5 C1,1 CH H H 1 1 o), 3 /e N i:cCN co W m M (D OD _Z2 Compound No. R 0 9 12 11 xr-" Cti-C[14 N-4CII=Cll!jEc- R R R Formula (IV) -6 Ct H3(C"3 Ct\ 3 cl 3 cif 3 Cif 3 11 11 1 1 cif -7 C-N 3 cif 3 c H 3 H I 1 S tyR- C2115 C2H5 H 11 1 soi-C-CH 3 01)11- 1 7 0 -9 () - c 3 11 7 c 3 H 7 H 11 1 c 2 11 5- so 4 c0 0 fl 3 c cif H 3 c cif 3 3 "' -10 c t,-, 3 c t CH 3 CH 3 H ct. 1 cif 3 so 4 -i t 0 O o G) ct cf.

(0 0 - cif CH H ct - 0 c 9.9 (n 3 3 4 @09 N > (0 GB2193659A 20 Other polymethine dyes are (b) merocyanine dyes of the formula:

A 1 i=CH - CHt- Cl - C (V) 5 11 0 in which represents the following rings, the benzene ring or naphthyl rings of which may be substituted 10 S H3C _CH3 fl N = 1 1 ≥= NO N 15 H3C 1 1 1 C2H5 L2MS LH3 0 S 20 ll,' IN CEN;:n:I., 1 C" 1 1 L2H5 C2Hs C2H5 25 and the like; C-\ 1 B OC-1 represents the following rings; 30 =C-N/ C2H5 =C - 111 QHs CO - NH 1 "C=S 1 C.Z, N.. I C S OC - N/' OC-0 -"CO - NH35 \C21-15 40 C - 0 1 1 0C CS S \ N / 1 J0:1 1 CO0C2Hs -'\CO 45 C2H5 and n is 1 or 2.

Further polymethine dyes are pyrylium dyes of the formulae: 50 ---Z-- 6X = (C-C) rn-1 =C - (C-C)n-R3. ye 55 1 12 1 4 1 2 (VI) R' R R R 60 2 e (=(C-C)m-lC-(C-C)n-C=C-(C-C)1-1-X Y 1 1 1 1 6 1 1 3 1 4 W R2 R5 R R 7 R R (VII) 65 21 GB2193659A 21 in which X, X1 and X2 are each a sulphur, oxygen or selenium atom; Z and Z' together with the adjacent chain structure form a pyrylium, thiopyrylium, selenapyrylium, benzopyrylium, benzothio pyrylium, benzoselenapyrylium, naphthopyrylium, naphthothiopyryliurn or naphthoselenapyrylium group which may be substituted; Z2 together with the adjacent chain structure forms a pyran, thiopyran, selenapyran, bezopyran, benzothiopyran, bezoselenapyran, naphthopyran, naphthothio- 5 pyran or naphthoselenapyran ring system which may be substituted; R1, R2, R3 and R4 are each a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group; R5, R6 and R7 are each a hydrogen or halogen atom or a substituted or unsubstituted alkyl, aryl or aralkyl group, rn and I are each 1 or 2; n is 0, 1 or 2; and Y is an acid anion.

An undercoat layer (between the substrate and recording layer) is used for the following 10 purposes: (a) improvement of adhesion of the recording layer to the substrate; (b) protection of the recording layer from water and gases; (c) improvement of the stability of the recording layer; (d) improvement of the reflection ratio of the recording layer; (e) protection of the substrate from solvents; and (f) to form pregrooves in the recording layer.

For purpose (a), a variety of polymeric materials such as ionomer resins, polyamide resins, 15 vinyl resins, natural polymeric materials, silicones and liquid rubber, and silane coupling agents can be employed.

For purposes (b) and (c), in addition to the above polymeric materials noted for use in (a), inorganic compounds, such as SiO, MgF2, SiO, TiO, SnO, TiN and SiN; and metals and metalloids, such as Zn, Cu, S, Ni, Cr, Ge, Se, Au, Ag and Al, can be employed. 20 For purpose (d), metals such as Ag and A[, and dyes having a metallic lustre, such as methine and xanthene dyes, can be employed.

For purposes (e) and (f), UV-curable resins, thermosetting resins, and thermoplastic resins can be employed.

The thickness of the undercoat layer is preferably from 0.1 to 30 'Um, more preferably from 25 0.2 to 10 ym.

The protective layer is formed in order to protect the recording layer from being scratched and smeared with dust, to give storage stability, and to improve the reflection ratio of the recording layer.

As materials for use in the protective layer, the same materials as those employed in the 30 undercoat layer can be employed.

The thickness of the protective layer is preferably from about 0.05 urn to about 5 um.

The undercoat layer and the protective layer can also contain stabilizing agents, dispersing agents, fireproofing agents, unguents, artistic agents, surface active agents and plasticizers.

Reference will now be made to the accompanying drawings which are schematic cross- 35 sections through recording media of the invention.

The recording medium shown in Fig. 1 comprises a substrate 1 having a recording layer 2 formed thereon, which recording layer 2 comprises a salt as specified above and a polymethine dye. The recording layer can be made of two layers, a light reflective layer and a light absorp tive layer, which can be formed in any order. 40 Another example of recording medium is shown in Fig. 2, in which medium an undercoat layer 3 is interposed between the substrate 1 and the recording layer 2.

In the recording medium shown in Fig. 3, a protective layer 4 is formed on the recording layer 2.

In the recording medium shown in Fig. 4 an undercoat layer 3 is interposed between the 45 substrate 1 and the recording layer 2, and an overcoat layer 4 is formed on the recording layer 2.

The above optical information recording media can be made into an airsandwich type medium by combining two recording media so that the two recording layers 2 are closely disposed in the inner side (using only one substrate as the case may be) or into a close-sandwich type by 50 combining the two recording media through the protective layer 4.

As the laser beams for the recording and reproduction of information with the recording media of the invention, semi-conductor laser beams having a wavelength of 750 to 850 nm can be preferably employed for the reduction in size a recording and reproduction apparatus to be used in which the recording medium is to be employed. 55 According to the invention, an optical information recording medium having good stability to heat and light, with a mininum deterioration in the course of reproduction is obtained. Further, by use of laser beams having a long wavelength, such as semi-conductor laser beams, information recording can be attained with high sensitivity in the form of pits.

In order that the invention may be well understood the following Examples are given by way 60 of illustration only.

Example 1 parts by weight of a polymethine dye of the following formula (1) and 15 parts by weight of a salt compound consisting of Cation A-1-1 and Metal Complex Anion B-1- 1 were dissolved 65 22 GB2193659A 22 in 1,2-dichloroethane to-prepare a solution.

0 H3C CH D CH3 H3C 0 0 C 5 C e 0 OV' CH = CH 4-3- CH 0 U04 N N I I LH3 CH3 The above solution was coated by spin coating on a substrate made of polymethyl methacry- 10 late having a thickness of 1.2 mm and a diameter of 200 mm, with a groove having a half-value width of 0.3 um, a depth of 950 A and a track pitch of 1.6 ym, extending with a radius ranging from 45 to 94 mm, so that a recording layer with a thickness of 700 A was formed on the substrate, whereby an optical information recording medium No. 1 according to the present invention was prepared. 15 Example 2

Example 1 was repeated except that the formulation of the polymethine dye and the salt compound employed in Example 1 was changed to the formulation of 70 parts by weight of a polymethine dye having the following formula and 30 parts by weight of a salt compound 20 consisting of Cation A-1-10 and Metal Complex Anion B-IV-1, whereby an optical information recording medium No. 2 according to the present invention was prepared.

S N>-4CH=CHi-j-CH SbF6e 25 N I L"3 CH3_ Example 3 30

Example 1 was repeated except that the formulation of the polymethine dye and the salt compound employed in Example 1 was changed to the formulation of 85 parts by weight of a polymethine dye having the following formula and 15 parts by weight of a salt compound consisting of Cation A-1-7 and Metal Complex Anion B-1-1, whereby an optical information recording medium No. 3 according to the present invention was prepared. 35 CH3 H3C CH3 CI G CII CH=cHir_CH C104 N 40 CH3 CH3 Example 4

Example 3 was repeated except that the salt compound employed in Example 3 was replaced 45 by a salt compound consisting of Cation A-1-4 and Metal Complex Anion B- 111-1, whereby an optical information recording medium No. 4 according to the present invention was prepared.

Example 5

Example 1 was repeated except that the thickness of the recording layer was decreased to 50 500 A and a; silver film having a thickness of 100 A was formed by vacuum evaporation on the recording layer, whereby an optical information recording medium No. 5 according to the present invention was prepared.

Example 6 55

A Te film layer having a thickness of 150 A was deposited by vacuum evaporation on the same substrate as that employed in Example 1.

parts by weight of the same polymethine dye as that employed in Example 1 and 40 parts by weight of the same salt compound as that employed in Example 1 were dissolved in 1,2 dichloroethane to prepare a solution. This solution was coated by spin coating gn the Te-film 60 layer deposited substrate, so that a recording layer having a thickness of 400 A was formed, whereby an optical information recording medium No. 6 according to the present invention was prepared.

Example 7 65

23 GB2193659A 23 Example 1 was repeated except that the formulation of the polymethine dye and the salt compound employed in Example 1 was changed tothe formulation of 80 parts by weight of a polymethine dye having the following formula and 20 parts by weight of a salt compound consisting of Cation A-1-10 and Metal Complex Anion B-1-2, whereby an optical information recording -medium No. 7 according to the present invention was prepared. 5 0 H3C CH3 H3C' CH3 0 co CH = C43- CH 0 C E04. 10 N L113 CH3 Example 8

90 parts by weight of a polymethine dye of the following formula and 10 parts by weight of a 15 salt compound consisting of Cation A-1-5 and Metal Complex Anion B-1-2 were dissolved in 1,2-dichloroethane to prepare a solution. This solution was coated by spin coating on a sub strate made of polycarbonate having the same groove as that made in the substrate employed in Example 1, so that a recording layer having a thickness of 700 A was formed, whereby an optical information recording medium No. 8 according to the present invention was prepared. 20 (CH3)2N -,D\ 0 N(CH312 -C (CH3)2N C ==4 CH - CH tg= CH \\\aN(CH3)2 C104 25 Example 9 30

Example 3 was repeated except that the thickness of the recording layer was changed to 500 A and a layer of a dye having the following formula was deposited with a thickness of 150 A on the recording layer by vacuum evaporation, whereby an optical information recording medium No. 9 according to the present invention was prepared.

35 oe S / S 0 CH- -CH '\' 0 ≥ - V 00:14 - 40 / I I - z I CH3 0 0 CH%3 0 0 45 Example 10

2 parts by weight of a salt compound consisting of Cation A-1-1 and Metal Complex Anion B-11-2 and 10 parts by weight of a silicone alcoholate composition (Colcoat N103K made by Taiyo Bussan Company, Ltd.) were dissolved in 1,2-dichloroethane to prepare a solution for forming an undercoat layer. This solution was coated on the same substrate as that employed in 50 Example 1 and was then hardened, so that an undercoat layer with a thickness of 1000 A was formed on the substrate.

On this undercoat layer, a recording layer having the same composition as that of the recording layer prepared in Example 3 was formed, whereby an optical information recording medium No. 10 according to the present invention was prepared. 55 Comparative Example 1 Example 1 was repeated except that only the polymethine dye employed in Example 1 was employed in the recording layer thereof, whereby a comparative optical information recording medium No. 1 was prepared. 60 Comparative Example 2 Example 3 was repeated except that only the polymethine dye employed in Example 3 was employed in the recording layer thereof, whereby a comparative optical information recording' medium No. 2 was prepared. 65 24 GB2193659A 24 Comparative Example 3 Example 8 was repeated except that only the polymethine dye employed in Example 8 was employed in. the recording layer thereof, whereby a comparative optical information recording medium No. 3 was prepared. 5 Comparative Example 4 Example 3 was repeated except that the salt compound employed in Example 3 was replaced by a compound having the following formula, whereby a comparative optical information record ing medium No. 4 was prepared: 10 /AOYN(C2H5)2 e C,=8=N Cl N Cú04 15 N (C21---15) 2 J Comparative Example 5 20 Example 3 was repeated except that the sa ' It compound employed in Example 3 was replaced by a compound having the following formula, whereby a comparative optical information record ing medium No. 5 was prepared:

CL Cl - e 25 CL 5 \ t 0 S Ni/S:C NK4H9)4 S S.' 1- Cl CL _j 30 Writing of optical information and reproduction thereof were performed on the substSpte side of each of the above recording media according to the present invention and the comparative recording media by use of semi-conductor laser beams having a wavelength of 790 pm, with a 35 recording frequency of 0.5 MHz, a fine speed of 1.5 m/sec. The reproduction waves were subjected to spectral analysis by use of a scanning filter with a band width of 30 KHz, so that the C/N (Carrier/Noise) of each optical medium was measured.

Further the optical recording media were subjected to an accelerated reproduction deterioration test by exposing each recording medium to 54000 lux light of a tungsten lamp for 20 hours. 40 Thereafter, the reflection ratio and the C/N of each recording medium were measured. The reflection ratio was measured from the substrate side of each recording medium. The above results are shown in the following Table 1.

z GB2193659A 25 Table 1

Initial Values Reproduction Preservability Deterioration Deterioration 5 Examples ReflectiSHn C/N -Reflection CIN Reflection C/N Ratio (%)_ (dB) Ratio (%) (dB) Ratio (%) (dB) Example 1 26 55 22 50 - - Example 2 23 54 is 47 - - 10 Example 3 27 55 22 52 20 50 Example 4 27 55 22 52 - 15 Example 5 31 47 27 44 - Example 6 43 51 39 50 - Example 7 25 55 18 49 - 20 Example 8 23 54 19 50 - Example 9 26 54 21 50 - 25 Example 10 28 57 22 52 - Comp.

Example 1 27 55 10 - Comp. 2_ 28 55 9 30 Example

Comp.

Example 3 27 55 12 Comp.

Example 26 54 23 51 15 45 Comp. 56-T 35 Example 5 27 6 18 49 21 50 Measurement Impossible 26 GB2193659A 26 Example 11

A groove was transferred to a disc-shaped substrate made of polymethyl methacrylate having a thickness of 1.2 mm and a diameter of 200 mm by a stamper including a guide groove having a width of 0.3 urn and a depth of 950 A, with a track pitch of 1.6 jim.

80 parts by weight of a polymethine dye of the following formula and 20 parts by weight of a 5 salt compound consisting of Cation A-1-1 and. Metal complex Anion B-VI-3 were dissolved in 1,2-dichloroethane to prepare a solution.

H3C -HI3 H3!:; CH3 10 C E) H=CH+3-CH C204 L"3 L"3 15 This solution was applied by spin coating to the above substrate, so that a recording layer with a thickness of 650 A was formed on the substrate, whereby an optical information recording medium No. 11 according to the present invention was prepared.

20 Example 12

Example 11 was repeated except that the salt compound employed in Example 11 was replaced by a salt compound consisting of Cation A-11-8 and Metal Complex Anion No. B-VI-3, whereby an optical information recording medium No. 12 according to the present invention was prepared. 25 Example 13

Example 11 was repeated except that the salt compound employed in Example 11 was replaced by a salt compound consisting of Cation A-111-8 and Metal Complex Anion B-VI-2, whereby an optical information recording medium No. 13 according to the present invention was 30 prepared.

Example 14

Example 3 was repeated except that the formulation of the polymethine dye and the salt compound employed in Example 11 was changed to the formulation of 90 parts by weight of a 35 polymethine dye having the following formula and 10 parts by weight of a salt compound consisting of Cation A-1-4 and Metal Complex Anion B-VII-5, whereby an optical information recording medium No. 14 according to the present invention was prepared.

\I 1-13C CH3 0 40 %(DN CH3 ' N \-- 4CH=H+,-CH 0 U04 E) 45. 1 1 45 CH3 LM3 Example 15

Example 14 was repeated except that the salt compound employed in Example 14 was 50 replaced by a salt compound consisting of Cation A-11-6 and Metal Complex Anion B-VII-6, whereby an optical information recording medium No. 15 according to the present invention was prepared.

Example 16 55

Example 14 was repeated except that the salt compound employed in Example 14 was replaced by a salt compound consisting of Cation A-111-1 and Metal Complex Anion B-VII-7, whereby an optical information recording medium No. 16 according to the present invention was prepared.

60 Example 17

Example 12 was repeated except that a silver film having a thickness of 100 A was formed by vacuum evaporation on the recording layer, whereby an optical information recording medium No. 17 according to the present invention was prepared.

27 GB2193659A 27 Example 18

Example 12 was repeated except that a Te film layer having a thickness of 100 A was deposited by vacuum evaporation on the substrate and the recording layer was then formed on the Te film layer, whereby an optical information recording medium No. 18 according to the present invention was prepared. 5 Example 19

Example 12 was repeated except that a layer of a pigment having the following formula was further formed with a thickness of 150 A by vacuum deposition on the recording layer, whereby an optical information recording medium No. 19 according to the present invention was prepared.

09 S 4g 0 ≥ CH CH 0 15 :P @N N 00 1 H 3% C 0 LM3 L113 0 20 Example 20

Example 11 was repeated except that the polymethine dye and the salt compound employed in Example 11 were respectively replaced by a polymethine dye having the following formula and a salt compound consisting of Cation A-11-8 and Metal Complex Anion B-VII- 5, whereby an optical information recording medium No. 20 according to the present invention was prepared. 25 0 CH3 C'O 30 0 CH= CH- CH = CH 0 N 4 0 ED _& N"ICH3 @ 6 35 Example 21

Example 20 was repeated except that the polymethine dye employed in Example 20 was replaced by a polymethine dye having the following formula, whereby an optical information recording medium No. 21 according to the present invention was prepared. 40 e (CH3ir-N--?-CH=CH-CH= C--&N(CH3)2 C104 2 2 45 Example 22

Example 11 was repeated except that the salt compound employed in Example 11 was replaced by a salt compound consisting of Cation A-1-1 and Metal Complex Anion B-VIII-1, 50 whereby an optical information recording medium No. 22 according to the present invention was prepared.

Example 23

Example 11 was repeated except that the salt compound employed in Example 11 was 55 replaced by a salt compound consisting of Cation A-11-6 and Metal Complex Anion B-VIIII-1, whereby a comparative optical information recording medium No. 23 was prepared.

Example 24

Example 11 was repeated except that the salt compound employed in Example 11 was 60 replaced by a salt compound consisting of Cation A-111-8 and Metal Complex Anion 13-VIII-3, whereby an optical information recording medium No. 24 according to the present invention was prepared.

Comparative Example 6 65 28 GB 2 193 659A 28 Example 11 was repeated except that only the polymethine dye employed in Example 11 was employed in the recording layer thereof, whereby a comparative optical information recording medium No. 6 was prepared.

Comparative Example 7 5 Example 14 was repeated except that only the polymethine dye employed in Example 14 was employed in the recording layer thereof, whereby a comparative optical information recording medium No. 7 was prepared.

Comparative Example 8 10 Example 20 was repeated except that only the polymethine dye employed in Example 20 was employed in the recording layer thereof, whereby a comparative optical information recording medium No. 8 was prepared.

Writing of optical information and reproduction thereof were performed on the substrate side 15 of each of the above recording media according to the present invention and the comparative recording media by use of semi-conductor laser beams having a wavelength of 790 ym, with a recording frequency of 0.5 MHz, a line speed of 1.5 m/sec. The reproduction waves were subjected to spectral analysis by use of a scanning filter with a band width of 30 KHz, so that the C/N (Carrier/Noise) of each optical medium was measured. 20 Further the optical recording media were subjected to an accelerated reproduction deterioration test by exposing each recording medium to 54000 lux light of a tungsten lamp for 20 hours.

Thereafter, the reflection ratio and the C/N of each recording medium were measured. The reflection ratio was measured from the substrate side of each recording medium, not at the groove, but at the flat portion thereof. The above results are shown in the following Table 2. 25 29 GB2193659A 29 Table 2

Initial Values Reproduction Deterioration Examples Reflection CIN Reflection C/N 5 Ratio (dB) Ratio (dB) Example 11 27.7 53 17.2 46 Example 12 27.2 52 20.9 48 10 Example 13 27.0 54 21.3 49 Example 14 28.3 54 18.9 48 15 Example 15 28.6 54 22.5 49 Example 16 28.0 55 21.2 49 20 Example 17 30.2 48 27.2 44 Example 18 42.2 49 39.7 45 25 Example 19 27.0 52 20.0 47 Example 20 20.3 51 16.6 46 Example 21 21.1 51 17.8 47 30 Example 22 27.3 53 18.3 46 Example 23 28.2 54 22.0 49 35 Example 24 27.7 53 20.8 48 Comp.

Example 6 28.0 53 10.2 4U Comp. 40 Example 7 28.2 53 12.2 Comp.

Example 8 27.8 53 8.9 Measurement Impossible 45 GB2193659A 30 Example 25 parts by weight of a polymethine dye of the following formula and 10 parts by weight of a salt compound consisting of Cation A-11-1 and Metal Complex Anion B-1-1 were dissolved in 1,2-dichloroethane to prepare a solution.

5 0 H3C ICH3 H3 CH3 CZN 0;4CH=CH+3-CH CLO4 1 1 10 LM3 U13 The above solution was coated by spin coating on a substrate made of polymethyl methacry late having a thickness of 1.2 mm and a diameter of 200 mm, so that a recording layer with a thickness of 700 A was formed on the substrate, whereby an optical information recording 15 medium No. 25 according to the present invention was prepared.

Example 26

Example 25 was repeated except that the formulation of the polymethine dye and the salt compound employed in Example 25 was changed to the formulation of 85 parts by weight of a 20 polymethine dye having the following formula and 15 parts by weight of a salt compound consisting of Cation A-11-5 and Metal Complex Anion B-1-2, whereby an optical information recording medium No. 26 according to the present invention was prepared.

CH3 H3C CH3 25 E) I CH = CH +3- CH U 04 N L"3 LM3 30 Example 27

Example 25 was repeated except that the formulation of the polymethine dye and the salt compound employed in Example 25 was changed to the formulation of 90 parts by weight of a polymethine dye having the following formula and 10 parts by weight of a salt compound 35 consisting of Cation A-11-1 1 and Metal Complex Anion B-11-2, whereby an optical information recording medium No. 27 according to the present invention was prepared.

0 8 40 CH3)-y-N- -C-CH=CH-CH= C NO 3)1]2 C104 02 2 2 Example 28 45

Example 25 was repeated except that a silver film having a thickness of 100 A was deposited by vacuum deposition on the recording layer thereof, whereby an optical information recording medium No. 28 according to the present invention was prepared.

Example 29, 50 A Te film layer having a thickness of 150 A was deposited by vacuum deposition on a substrate made of polymethyl methacrylate having a thickness of 1.2 mm.

parts by weight of the same polymethine dye as that employed in Example 26 and 15 parts by weight of the same salt compound as that employed in Example 26 were dissolved in 1,2-dichloroethane to prepare a solution. This solution was coated by spin coating gn the Te- 55 film layer deposited substrate, so that a recording layer having a thickness of 400 A was formed, whereby an optical information recording medium No. 29 according to the present invention was prepared.

Example 30 60 parts by weight of a salt compound consisting of Cation A-41-8 and Metal Complex Anion B-1-1 and 70 parts by weight of a pigment having the following formula (1) were dissolved in 1,2-dichloroethane to prepare a solution.

31 GB2193659A 31 0 1 ZCH3 (D 5 0 CH =CH - CH =CH--aN \-,c C104 0 9 H3 @ 19 10 This solution was coated by spin coating on a substrate made of polycarbonate having a thickness of 1.2 mm, so that a recording layer having a thickness of 600 A was formed '.

The thus formed recording layer, a compound having the following formula (2) was deposited with a thickness of 150 A by vacuum deposition, whereby an optical information recording 15 medium No. 30 according to the present invention was prepared.

e 0 S 20 CH CH-<p7 0 0 ≥ N I -A0 I @ C2rIS QH% 0 0 25 Example 31

2 parts by weight of Metal Complex Anion B-1-2 in the form of ammonium salt, and a silicone alcoholate composition (Colcoat N103K made by Taiyo Bussan Company, Ltd.) were dissolved in 1,2-dichloroethane to prepare a solution for forming an undercoat layer. This solution was coated on the same substrate as that employed in.Example 26 and was then 30 hardened, so that an undercoat layer with a thickness of 1000 A was formed on the substrate.

On this undercoat layer, a recording layer having the same composition as that of the recording layer prepared in Example 26 was formed, whereby an optical information recording medium No. 31 according to the present invention was prepared.

35 Example 32

Example 25 was repeated except that the formulation of the polymethine dye and the salt compound employed in Example 25 were changed to the formulation of 90 parts by weight of a polymethine dye having the following formula and 10 parts by weight of a salt compound consisting of Cation A-11-10 and Metal Complex Anion B-1-1, whereby an optical information 40 recording medium No. 32 according to the present invention was prepared.

0 H3C CH3 H3C CH #3 CH = CH 004 45 %0 e 3 3 EN) N I I Ln3 CH3 Example 33 50

Example 25 was repeated except that the formulation of the polymethine dye and the salt compound employed in Example 25 were changed to the formulation of 85 parts by weight of a polymethine dye having the following formula and 15 parts by weight of a salt compound consisting of Cation A-11-1 and Metal Complex Anion B-1-1, whereby an optical information recording medium No. 33 according to the present invention was prepared. 55 Br _3C\ _CH3 H3 CH3 Br 14 E) WEV-4 C H = CH N CLO4 60 1 1 L2"S LPS Example 34

Example 25 was repeated except that the formulation of the polymethine dye and the salt 65 I 32 GB2193659A 32 compound employed in Example 25 were changed to the formulation of 80 parts by weight of a polymethine dye having the following formula and 20 parts by weight of a salt compound consisting of Cation A-11-5 and Metal Complex Anion B-111-2, whereby an optical information recording medium No. 34 according to the present invention was prepared.

5 H3C CH H C CH3 IL Lr_13 cf"'y/N-4 3 - CI e CH = CH+, 004 N.3 N 1 1 10 L2115 C2115 Comparative Example 9 Example 25 was repeated except that only the polymethine dye employed in Example 25 was employed in the recording layer thereof, whereby a comparative optical information recording 15 medium No. 9 was prepared.

Comparative Example 10 Example 25 was repeated except that only the polymethine dye employed in Example 26 was employed in the recording layer thereof, whereby a comparative optical information recording 20 medium No. 10 was prepared.

Comparative Example 11 Example 27 was repeated except that only the polymethine dye employed in Example 27 was employed in the recording layer thereof, whereby a comparative optical information recording 25 medium No. 11 was prepared.

Writing of optical information and reproduction thereof were performed on the substrate side of each of the above recording media according to the present invention and the comparative recording media by use of semi-conductor laser beams having a wavelength of 790 'Um, with a 30 recording frequency of 0.5 MHz, a line speed of 1.5 m/sec. The reproduction waves were subjected to spectral analysis by use of a scanning filter with a band width of 30 KHz, so that the C/N (Carrier/Noise) of each optical medium was measured.

Further the optical recording media were subjected to an accelerated reproduction deterioration test by exposing each recording medium to 54000 lux light of a tungsten lamp for 20 hours. 35 Thereafter, the reflection ratio and the C/N of each recording medium were measured. The reflection ratio was measured from the substrate side of each recording medium, not at the groove, but at the flat portion thereof. The above results are shown in the following Table 3.

33 GB2193659A 33 Table 3

Initial Values Reproduction Deterioration 5 Examples Reflection C/N Reflection CIN Ratio (%) (dB) Ratio (%) - (dB) Example 25 27.3 55 22.6 52 10 1 Example 26 26.2 55 20.9 51 Example 27 25.5 54 20.5 51 Example 28 31.2 49 28.0 46 15 Example 29 43.3 51 39.3 48 Example 30 25.7 51 20.6 49 20 Example 31 26.3 55 22.0 52 Example 32 27.4 55 22.4 51 Example 33 26.8 54 21.2 51 25 Example 34 26.6 55 20.9 52 Comp.

Example 9 28.9 58 12.7 Comp. 30 Ex le 10 28.0 58 10.2 j co P. --r5 E 1 11 25.0 6 1 12.2 Measurement Impossible 35 34 GB2193659A 34

Claims

1. An optical information recording medium comprising a substrate bearing a recording layer containing a polymethine dye and a salt of a metal complex anion with a cation of the formula:

5 1.1 R ' 1 m± (I Z = N = A - N R 2 10 in which Z represents a group 0 15 which group may be substituted with a C,-C,6 alkyl group, a C,-C, alkoxy group; R or a group -CO-N 1.1 20 1. R 16 (wherein R15 and R16 are each hydrogen, a C,-C, alkyl group or a phenyl group), and/or the phenyl group in the group Z may form a condensed aromatic ring; R' and R2 are each a C,-C, alkyl group or a phenyl group [which may be substituted with 25 halogen or a C,-C, alkyl group, a Cl-C6 alkoxyl group or a di(C1-C6 alkyl) amino group]; m is 1 or 2. and A is a group n 30 (where n is 1 or 2 and which may be substituted with halogen or a Cl-C6 alkyl group, a Cl-C, alkoxyl group or a hydroxyl group), or, when m is 2, a group 35 R 3 R 40 N -N-9-N 5 M19 1-- N- CO -A 6 (A - 11) R R 2 in which R3, R4, R5 and R6 are each hydrogen or a substituted or unsubstituted C,-C, alkyl 45 group; and A and m have the meanings defined above; or E) X 0 N 0 X 50 (A-III) (0 Y in which X is (i) a phenyl group which may be substituted with a C,-C, alkyl group, a Cl-C6 55 alkoxyl group, a Cl-C, alkylthio group, halogen or hydroxyl group, (5) a cyclohexylamino group, (iii) a benzylamino group the phenyl moiety of whch may be substituted with halogen, a C,-C, alkyl group, a C,-C, alkoxyl group, a Cl-C, alkylthio group or a hydroxyl group, or (iv) a di(C,_C4 alkyl) amino group; and Y has the same meaning as X or is hydrogen, halogen, a C,-C, alkyl, alkoxy or alkylthio group or a hydroxyl group. 60 2. A recording medium as claimed in claim 1 in which the metal complex anion has the formula:

GB2193659A 35 e R2 0 R3 S / \ 5 R 3 5 - R4 R 4 - in which R1,13 2, R3 and R4 are each a hydrogen or halogen atom, a Cl-C6 alkyl group (which may be substituted with a hydroxyl group or alkyl group or benzyl group) and M is Ni, Co, Mn, Cu, Pcl and Pt. 10 3. A recording medium as claimed in claim 1 in which the metal complex anion has the formula:

RS S s F - e 15 R 6.S S R8, in which R', R6, R7 and W' are each a Cl-C, alkyl group (which may be substituted with halogen, 20 a hydroxyl group or a Cl-C, alkoxy group), an aryl group (which may be substituted with halogen, a hydroxyl group,, a Cl-C, alkyl group, a C,-C, alkoxy group, a cyano group, a nitro group or an amino group), an amino group (which may be substituted with a Cl-C6 alkyl group or a benzyl group), or a cyano group; and M is Ni, Mn, Cu, Pcl or Pt.

4. A recording medium as claimed in claim 1 in which the metal complex anion has the 25 formula:

- R' W R2 S -., S F30 R 00 S M..IS 00- R3 R R 4 in which W, R2, R3, R4 and M have the meanings defined in claim 2. 35 5. A recording medium as claimed in claim 1 in which the metal complex anion has the formula:

- W W - e R 2 R 2 40 3 0 0 R 0 0 R 3 R 4 R 4 45 in which W, R, R3, R4 and M have the meanings defined in claim 2.

6. A recording medium as claimed in claim 1 in which the metal complex anion has the formula:

IR, R 2 3- e 50 ely W R R (V) R3V n 0 4 R S 1. M 1.1 5 0 R ' - 0 1.1 11.10: 55 in which R', R2, R3, R4 and M have the meanings defined in claim 2.

7. A recording medium as clai-med in claim 1 in which the metal complex anion has the formula:

60 NC S S R9]e X]- (V1) [ N S ' 1 -, S ' WO 36 GB 2 193 659A 36 in which R9 and RIO are each hydrogen, a cyano group, a C1_C6 alkyl (which may be substituted with a hydroxyl group or a C1_C4 alkoxy group), or an aryl grup (which may be substituted with halogen, a hydroxyl group, a Cl-C, alkyl group, a C1_C4 alkoxy group, a cyano group, a nitro group or an amino group); and M is Ni, Co, Mn, Cu, Pd or pt.

8. A recording medium as claimed in claim 1 in which the metal complex anion has the 5 formula:

W1 _e W2 S S R 9 (Vil) 10 "' "' 1 I/M1_1 3 0 S SX0 14 in which R9 and RIO and M have the meanings defined in claim 7; and R"', RI2, R13 and R14 are 15 each hydrogen or halogen or a cyano or hydroxyl group; and the phenyl group in the formula may be condensed with another aromatic ring.

9. A recording medium as claimed in claim 1 in which the metal complex anion has the formula:

20 e R 12 0 N S S'( R 9 (Vill) R1N'S"'M''S- 13,, 'I, R10 14 25 in which R9 RIO, RII, R12, R13, R14 and M have the meanings defined in claim 8.

10. A recording medium as claimed in any one of the preceding claims further comprising an undercoat layer interposed between the substrate and the recording layer. 30 11. A recording medium as claimed in any one f the preceding claims further comprising a protective layer on the recording layer.

12. A recording medium as claimed in any one of the preceding claims in which the sub- strate is made of a polyester, acrylic resin, polycarbonate, polyamide, polyolefin resin, phenolic resin, epoxy resin and polyimide, glass, ceramics or metals. 35 13. A recording medium as claimed in any one f the preceding claims in which the weight ratio of the polymethine dye to the salt in the recording layer is from 40:60 to 99:1.

14. A recording medium as claimed in any one of the preceding claims in which the record- ing layer has a thickness of from 100 A to 5 um.

15. A recording medium as claimed in claim 1 substantially as hereinbefore described with 40 reference to the Examples.

Published 1988 at The Patent Office, State House, 66/71 High Holborn, London WC 1 R 4TP. Further copies may be obtained from The Patent Office, Sales Branc, St Mary Cray, Orpington, Kent BF15 3RD. Printed by Burgess & Son (Abingdon) Ltd. Con. 1/87.