JPH0239989A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain specific threshold properties and excellent preservation stability by using a thin film comprising a mixture of at least two different organic coloring matter compound, one of which has a specific ion in the molecule thereof and another of which has a specified metallic element in the molecule thereof. CONSTITUTION:A thin film comprising as a main constituent an organic coloring matter compound A having on ion of the formula XOn<-> (X is halogen, and n is an integer of 1-4) and an organic coloring matter compound B having a metallic atom selected from the group consisting of Ti, V, Cr, Fe, Mn, Co, Ni, Sn and W, is provided on a substrate. An optical recording medium having the organic thin film using the mixture of the specified organic coloring matter compound A and the specified organic coloring matter compound B, in correlation with the mixed coloring matter system having a sharp refraction point of a thermal decomposition curve in thermal decomposition characteristics, has excellent threshold properties, namely, a large difference in property changes of the coloring matters due to the difference between writing power and reading power. Further, the recording medium has excellent resistance to light and moist heat and high sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical recording medium, and particularly to an optical recording medium using an organic dye and having excellent threshold properties.

(Prior Art) In recent years, the development of semiconductor lasers has been remarkable, and small and stable oscillators have become available at low cost and have begun to be used as light sources for various recording devices. However, the wavelengths of these conductor lasers are limited to relatively long wavelengths, and semiconductor lasers capable of oscillating short wavelength light have problems in terms of lifespan, output, etc. Therefore, it is essential to use a material that absorbs in the near-infrared region as a thin film layer for a μ conductor laser recording medium, and materials with a maximum absorption wavelength of 750/Jj1 or less are unsuitable. Conventionally, as this type of recording medium, there is one in which a thin film formed on a substrate is irradiated with laser light to form pits, and recorded information is read out based on the difference in reflectance between pits and non-pit areas. The structure of the recording layer for recording and reproduction (reading) may be two or more layers consisting of a recording thin film forming layer and a reflective film, but it is advantageous to have only a recording thin film layer that has both of the above functions. be.

In the case of a single-layer film for this recording thin film layer, it is necessary that the material of the recording thin film layer itself has a high reflectance in order to obtain a high S/N ratio. This type of recording medium is
Inorganic systems using low melting point metals such as Te or its alloys are known, and zero organic systems are known that use cyanine dyes and phthalocyanine compounds.

(Problems to be Solved by the Invention) Inorganic optical recording media using Te-based alloys have relatively high sensitivity, but they have problems with toxicity, and the film formation method uses sputtering, etc., resulting in high equipment costs. (However, productivity is also a drawback. Organic thin-film optical recording media using cyanine dyes have the advantage of being able to be produced using relatively inexpensive methods such as the spin-coding method. Currently, the state of storage stability (durability), for example, has not yet reached a satisfactory level.In addition, naphthoquinone and anthraquinone-based materials have poor solubility in solvents, and there are problems with storage stability such as the formation of agglomerated structures. Furthermore, in the case of phthalocyanine compounds, they were unsatisfactory due to solvent solubility, semiconductor laser matching properties, crystal changes during storage, etc.

(Means for Solving the Problems) The present invention provides an optical recording medium using an organic dye-based thin film that has high sensitivity, excellent threshold properties, and excellent storage stability and solvent solubility. In other words, an organic dye compound CA) having an ion represented by XOn- (where,
An optical recording medium characterized by forming a thin film on a substrate, the main component being an organic dye compound [B] having a metal atom selected from the group consisting of e, Mn, 'Co+NiISn*W. It is.

That is, the present invention uses a thin film in which two or more different organic dye compounds are mixed: an organic dye compound [A] having a specific ion in the molecule and an organic dye compound (B) having a specific metal element in the molecule. This provides an optical recording medium that meets unique threshold properties and has excellent storage stability.

The organic dye compound [A] used in the present invention is not particularly limited as long as it contains an oxygen halogen ion in the molecule, but as the oxygen halogen ion 7, CQ
04-, CQ, 03-.

CC! 02-, CQ, O-, B rO, +-, B r
ob-, IO, s, etc., among which CC04- is preferred.

CQ,O,J-,BrO,t-,Broar-,I
As in 04-t r O*, n is 3 or more and -1-, and preferred examples of the striking machine dye compound containing these specific ions in the molecule are polymethine compounds and amine compounds.

The organic dye compound [B] used in the present invention includes TI, V+ Cr, Fe, Mn+ Co+Nl, S
Any material may have a metal atom selected from the group of n and W (although not particularly limited, phthalocyanine compounds and naphthalocyanine compounds are preferred. (B)
When a metal atom is contained in the molecule, it may be in any state, but it suffices if the metal atom is contained in the molecule in a state such as a coordinate bond or an ionic bond. It may be present in the molecule together with the metal atom.

The abundance ratio of [A) and (B) in the thin film of the present invention is not particularly limited, but the ratio is preferably 5795 to 9515, more preferably 15/85 to 85/15.

The optical recording medium of the present invention is one in which a mixture of a specific organic dye compound [A] and a specific organic dye compound [B] is formed as a thin film on a substrate. Unless otherwise specified, stabilizers, lubricants, antistatic agents, polymer compounds as binders, other dyes, and sensitizers may be used in combination with the mixed system. The substrate material used in the present invention may be transparent or opaque to the laser beam used, but when writing and recording is performed using the laser beam from the substrate side, it must be transparent to the laser beam. These substrate materials include glass, acrylic resin, methacrylic resin, polyester resin, nitrocellulose resin, polyamide resin, polycarbonate resin,
Examples include polymethylpentene-1 resin, epoxy resin, vinyl chloride resin, polyparaphenylene resin, and the like. These resins are shaped into sheets, films, discs, etc., and these shaped products are coated with a coated layer or coated as necessary.
It may have a layer coated with a specific metal.

Hereinafter, the present invention will be explained in more detail with reference to Examples. The characteristics in the examples were measured and evaluated as follows.

[Reflectance]

Mix organic dye compound [A] and organic dye compound [B] at a predetermined mixing ratio, and add 1.5 f of the mixture to dichloroethane.
f (In%) and formed on a glass substrate with a spin coater to a solid content thickness of 70 nm.

Use this with a UV-VIS spectrometer (Kinsei Manufacturing Co., Ltd.)
The reflection spectrum was measured by irradiating light from the substrate side at UV21 OA), and the reflectance (R,%) at a wavelength of 830 nm was determined.
) was sought.

[Recording characteristics]

The same sample as described in the [Reflectance] section was used at 830 nm).
A laser beam of 7mW was focused on the diameter of one door using a lens to perform 8 inscriptions, and then the same laser light source was used to irradiate 0.
．． Read out at 5 mW, C/N ratio of reflected light is 50 dB or more.
We measured the writing light pulse width and calculated the reciprocal of the sensitivity.

[Light resistance]

The recording medium obtained in the same manner as in the previous section was irradiated with a sunshine carbon arc fade meter at 63° C. for 300 hours, and then the reflectance C/N ratio was measured to determine deterioration.

[Moisture heat resistance]

The recording medium obtained in the same manner as in the previous section was stored at 70° C. and 90% RH for 3 months, and the reflectance and C/N ratio were measured.

[Threshold property]

A recording medium obtained in the same manner as in the previous section was used at a rotation speed of 11 m/s (measurement position), a frequency of 2 MHz + a wavelength of 830 nm, a beam diameter of 1 unit, and a writing power of 1.5 mW and 2.0 mW.
The C/N ratio was determined at each stage when reading was performed at a read power of 0.2 mW.

[Thermal decomposition characteristics]

Data at a temperature rate of 5°C/m1nff in an air atmosphere was obtained using DT A-DT G manufactured by Rigaku Denki.
艷J.

(Example) Each example N (organic dye compound corresponding to L [A
] and organic dye compound [B] in the weight ratio shown below was dissolved in dichloroethane at 1.5% by weight and coated on a glass substrate with a spin coater to form a thin film with a solid content thickness of 701 m. to obtain each sample (recording medium). Various characteristics were measured and evaluated for each sample. The results are shown in Table-■. Compounds other than [A] and [B] are [C]
It was expressed as

Incidentally, FIG. 1 shows the thermal decomposition characteristics of the predetermined mixed dye of Example-1 and FIG. 2 shows the predetermined mixed dye of Comparative Example-8.

In addition, in the formula representing the compound, Me represents a methyl group, t-
Bu is a tertiary-butyl group, Et is an ethyl group, B
u represents a normal butyl group, and He represents a normal hexyl group.

Example-1 A, /B, near 5/25 H2 ・t Bu Example-2 A2/B2=50150 1ru proverb-5O鵞NH (,H) Example-4 A4/B4=75/75 ・[ Yes] - Ichigo! Hi-Me Example-3 C, /A3/B, += 40/ 10150A% [(Ms)iN○i z N'O:N'' I○NfMe1
Mountain) 2CiO4 Example-5 A3/B5/A3-2=40150/IOA Lark(1(Met 2NQl Snow NQ◎N”l◎N+Ma1
City] rQe Example-6 As/BG=20/80 Comparative example-8 A8/C,=80/20 Comparative example-7 C,/B7=80/20 ■ (Effect of the invention) Specific organic dye of the present invention In the optical recording medium of an organic thin film using a mixture of the compound [A] and the specific organic dye compound [B], it is a mixed dye system that has a sharp refraction point of the thermal decomposition curve, as is clear from the thermal decomposition characteristics. Correlating with this, it has excellent threshold holding properties, that is, there is a large difference in pigment discoloration (fI) due to the difference between the power during writing and the power during reading, and it also has excellent light resistance and moisture and heat resistance. It becomes a highly sensitive recording medium.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the thermal decomposition characteristics of the mixed dye of Example-1, and FIG. 2 is a diagram showing the thermal decomposition characteristics of the mixed dye of Comparative Example 8. 11 people for patent Toyobo Co., Ltd. weight 1oss ('/,)

Claims (1)

[Claims] (1) A thin film containing as main components an organic dye compound [A] having an ion represented by the following formula [I] and an organic dye compound [B] having a metal selected from the group [II] below is deposited on a substrate. An optical recording medium characterized by being formed in. [I] Formula;
n.W.