JPS6190342A - optical information storage medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an optical information storage medium having a light-absorbing and reflective dye film on a convex portion on a substrate. More particularly, the present invention relates to optical disk memory media for use in original disk memory devices.

[Prior art]

Conventionally, optical information storage media using a thin dye film as a recording layer have been used. As shown in FIG. 2, this type of optical information storage medium 1 is composed of a transparent substrate 2 and a dye film 3.

When used conveniently as the optical information storage medium 1, there is a known method of recording and reproducing by condensing and irradiating a laser beam 4 from the substrate 2 side using a condensing lens 5, which eliminates the need for the substrate 2 to be transparent. There is.

Information is recorded by irradiating the laser beam 4 with a high power, and the pigment film 3 is thermally changed by the original energy absorbed by itself to form small holes (pits), depending on the presence or absence of the small holes. On the other hand, information is reproduced by irradiating a laser beam with a low power that does not destroy the pigment film and detecting the presence or absence of small holes based on the light reflected from the pigment film. Storage media with this structure can be manufactured by coating, which is an extremely productive method, and has the advantage of being industrially produced at low cost. is quite difficult.

Therefore, as shown in FIG. 6, the inventors set the pigment film thick so that the pregroove or pit 6 is formed as a recess when viewed from the pigment film 3, thereby maximizing the reflectance. I suggested that you do it first. however,
Due to the fluidity of the solution during dye application, there is a problem in that the thickness of the dye film in the recessed portion is thicker than in the surrounding area. Usually, the depth of the depression is 500 to 1 soi, but the thickness of the pigment film is 300
When applied to ~1000A, the thickness of the recessed area will be approximately 10 to 100% thicker than the surrounding area.The thicker the dye, the more difficult it is to be removed by the heat of the laser beam during recording, resulting in lower sensitivity. Errors are likely to occur in the reproduced signal due to a decrease in the thickness of the pigment film, an increase in noise, and an increase in jitter due to waveform interference. Since the reflectance differs between thinner and thicker areas, the reflected light from the pregroove or preformat no longer interferes with each other, resulting in a weak preformat signal and tracking error signal.

〔the purpose〕

The present invention has been made in view of the above-mentioned current situation, and its purpose is to reduce detection errors of preformat signals in an optical information storage medium in which a light absorbing reflective dye is coated on a pregroove or preformat substrate. This includes improving the quality of the reproduced signal from the information recording section and lowering the error range.

〔composition〕

In order to achieve the above object, the present invention provides an optical information storage medium in which a light-absorbing and reflective dye film is provided by coating on a pre-groove or a pre-format pit row formed in a convex manner on a substrate. The goal is to provide the following.

As is already known, the pregroove enables signal detection for tracking control when irradiating a recording or reproducing laser beam, and the preformat is used to detect addresses or other system configurations. A pregroove or preformat is usually convex and has a height of 0.05Am = C.
L about 15 pm, its width is 0.311 m to 1.0 μ
m is selected. However, since it is designed by a known method based on the laser beam diameter and optical wavelength, it is not limited to this value.

The light-absorbing and reflective dye in the present invention is not particularly limited.
A material that provides a reflectance of ~30% comparable to that of a metal can be appropriately selected, and representative examples thereof include cyanine dyes and merocyanine dyes.

Furthermore, the dye film in the present invention does not need to be formed by the dye alone (it may be formed by mixing it with other dyes or by mixing it with a stabilizer such as a nickel complex). The dye film may also contain other polymeric substances, various plasticizers, surfactants, antistatic agents, lubricants, flame retardants, dispersants, etc.For the formation of the dye film, a dye solvent solution is used as a substrate. A protective layer may be provided on top of the pigment film, or a protective layer may be provided below the pigment film, as necessary. A tension layer may also be provided.

In the present invention, the material of the substrate on which the dye film is provided is not particularly limited, and may be any material such as plastic, glass, ceramics, metal, etc.

Furthermore, the storage medium of the present invention may have the above-mentioned dye film on one surface of such a substrate (or may have a dye film on both surfaces thereof. It is also possible to form a so-called sand-inch structure in which a pair of dye films are disposed on each other and arranged so that the dye films face each other.

Next, a preferred embodiment of the present invention will be explained with reference to FIG.

In the optical information storage medium 1 of the present invention, a trap pregroove or preformat bit 7 is formed on a substrate 2 so as to be convex when viewed from the surface of the dye film 3, and the dye film 3 is provided thereon. With this configuration, the dye film is formed so that the dye film is thinner in the pregroove or preformat bit area, so the dye film thickness on the convex portions 7 can be adjusted to reduce recording sensitivity and reduce jitter due to waveform interference. Even if it is thinned to such an extent that no increase occurs, the surrounding films (, 11) are thick enough to provide sufficient reflectance, making it possible to increase the preformat signal and tracking error signal levels.

〔Example〕

The present invention will be further explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 On an acrylic plate with a thickness of 1.15111 mm, a pregroove having a convex portion with a track pitch of 2.0 μm, width of 0.6 μm, and height of 70X was formed using the 7otobolimer method. Pigment Research Institute NK28
85) was dissolved in dichloroethane and applied to prepare an optical information storage medium. At this time, the pigment film thickness on the pregroove is 500×, and the pigment film thickness on other parts is 750×
And so.

Akira, (J○4 Ako.

θ Example 2 Example 1 was formed on an acrylic plate with a thickness of 1.15·n and a pregroove having a track pitch of 2.011 m, a width of 0.7 μm, and a convex portion of 900 mm in height by the 7 otobolimer method. An optical information storage medium was fabricated by coating the cyanine dye used in dichloroethane. At this time, the thickness of the dye film on the pregroove was set to 500 mm, and the thickness of the dye film on other parts was set to 800 mm.

Example 3 Thickness 1. Track pitch 2.0μm X'! by photopolymer method on i5nm acrylic board. m 0.6μm
An optical information storage medium was prepared by forming a pregroove having a convex portion with a height of 50×1 and coating the cyanine dye used in Example 1 with dichloroethane on a lubricant plate. At this time, the thickness of the dye film on the pregroove was set to 500 mm, and the thickness of the dye film on other parts was set to 680 mm.

Example 4 A triarylmethane dye of the following formula was formed on an acrylic plate with a thickness of 1.1511 m using a photopolymer method to form a pregroove having a track pitch of 2.0 μm, width of 0.6 μm, and a height of 700×. (Hodogaya Chemical Eisen Victoria Blue BH) was dissolved in ethanol and applied to produce an optical information storage medium. At this time, the thickness of the dye film on the pregroove was set to 500 OA, and the thickness of the dye film on other parts was set to 75 OA.

fi3L; ui3 Comparative Example 1 Track pitch 2.0 μm 1 width 0.6 μm 1 depth 7 on an acrylic plate 1.151 m thick by photopolymer method
A cyanine dye was applied in the same manner as in Example 1 onto a substrate on which pregrooves having ooX recesses were formed to produce a storage medium. At this time, the thickness of the pigment film on the pregroove was set to 50
0X, and the dye film thickness in other parts was 300X.

Comparative Example 2 In Comparative Example 1, the pigment film thickness on the pregroove was changed to 7soX.
A storage medium was produced in the same manner as in Comparative Example 1 except that the thickness of the dye film in other parts was 50 OA.

Comparative Example 3 Same as in Example 2, on an acrylic board with a thickness of 1.15*jl, a pregroove with a track pitch of 2.0 μm, a width of 0.7 μm, and a depth of 900× was formed using the 7 otobolimer method. A storage medium was prepared by applying a cyanine dye. At this time, the thickness of the pigment film on the pregroove was
ooX, and the dye film thickness in other parts was 270X.

Comparative Example 4 In Comparative Example 3, the pigment film thickness on the pregroove was changed to 800X.
A storage medium was produced in the same manner as in Comparative Example 3 except that the thickness of the dye film in other parts was 5ooX.

Comparative example 5 Thickness 1. Track pitch 2.0 μm 1 width 0.6 ttm on IEll's acrylic board by photopolymer method
A cyanine dye was applied in the same manner as in Example 3 onto a substrate on which a pregroove having a recessed portion with a depth of 500 A was formed to produce a storage medium. At this time, the thickness of the dye film on the pregroove was set to 500X, and the thickness of the dye film on other parts was set to 370X.

Comparative Example 6 In Comparative Example 5 VC, the pigment film thickness on the pregroove is 680
A storage medium was produced in the same manner as in Comparative Example 5, except that the thickness of the dye film in the other portions was 500.

Comparative Example 7 Track pitch 2.0 μm 1 width 0.6 μm 1 was formed by photopolymer method on an acrylic plate with a thickness of 1.15 ml.
A storage medium was prepared by applying a triarylmethane dye in the same manner as in Example 4 onto a substrate in which a pregroove having a recessed portion having a depth of 700λ was formed. At this time, the thickness of the dye film on the pregroove was set to 5ooX, and the thickness of the dye film on other parts was set to 3OOI.

Comparative Example 8 In Comparative Example 7, the pigment film thickness on the pregroove was set to 750″.
A storage medium was produced in the same manner as in Comparative Example 7 except that the thickness of the dye film in the other portions was 500^.

Next, the wavelength 7
Using a 90 nm semiconductor laser at a linear velocity of 1.24 m/
sea, information is recorded with a laser beam diameter of 0.9 μm (half width), and the recording power and tracking error signal (relative value) at which the eye pattern judgment level is zero are measured, and the results are summarized in the table below. .

Example 1 1 2.2 # 2
1 2, 2# 3
1 2,2# 4 1
2.3 Comparative Example 1 0.7
2.2# 2 1 2
,7s 3 0.68 2.2f
f 4 1 2.7s 5
0.76 2.2# 6
1 2,5s 7 0.
75. 2.3I8.1 2
．． B [Effects] According to the optical information storage medium of the present invention, the following advantages can be obtained.

(1) Lower recording laser power (possible (when tracking error signals are made the same).

(2) The tracking error signal can be increased (when the storage laser power is the same).

(3) Less waveform interference (and fewer errors).

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a preferred example of the optical information storage medium according to the present invention, and FIGS. 2 and ! FIG. 1 is a sectional view showing the structure of a conventional optical information storage medium. 1... Optical information storage medium, 2... Substrate, 6...
Pigment film, 4... Laser beam, 5... Condenser lens,
6, 7... Pre-groove or pit. 1.
1 Indication of death Patent Application No. 209697 of 1980 3. Relationship with the person making the amendment qi - Patent Department I (it) Address: 1-113-6 Nakamagome, Ota-ku, Tokyo Name (674) Co., Ltd. Ricoh - 1. Representation (7. Contents of amendment, page 14, lines 2 to 6 [to the storage medium... wave]) to 79
0nmJ for Example 1, Comparative Example 7 and Comparative Example 8, grown in the same medium as described above using a 633nrn'.
Correct it to 90nml. that's all

Claims (1)

[Claims] 1. An optical information storage medium, characterized in that a light-absorbing and reflective dye film is provided by coating on a pre-groove or pre-format pit row formed in a convex manner on a substrate.