JPH02154337A - optical disk - 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 [Industrial Field of Application] The present invention relates to an optical disc, particularly a heat mode optical recording disc.

[Prior Art] Conventionally, optical discs have the following characteristics: (1) Since the head is non-contact during recording and playback, the disc does not wear out; (2)
It has the following characteristics: (1) resistance to scratches and dirt; and (3) excellent long-term stability.

Among such optical discs, heat mode optical discs in particular are attracting attention because they do not require development.

The heat moat optical recording method on optical discs involves irradiating the recording layer with light such as a laser, and the heat generated at that time causes a portion of the recording layer to melt and decompose into two parts.

This is done by decolorizing, removing, etc., and forming small holes called pits.

In such pit-forming type optical discs,
Due to issues such as recording sensitivity, it is preferable to have a hollow structure (air sandwich structure).

This hollow structure is formed by integrating a transparent disk substrate having a recording layer and a protective substrate, which is the other substrate, with the recording layer inside with a predetermined gap interposed therebetween. As a specific method, a method is known in which doughnut-shaped spacers are interposed between the inner and outer circumferences of a disk-shaped substrate and a protective substrate is bonded to the disk-shaped substrate.

[Problems to be Solved by the Invention] However, the above-mentioned conventional example has disadvantages in that it is difficult to align the spacers and the dynamic balance is likely to be lost. Also, if the adhesive fills the recording area,
It also had the disadvantage of damaging the recording layer.

The present invention has been made in order to improve the drawbacks of the conventional example, and provides an optical disc that prevents adhesive from protruding into the recording area, prevents damage to the recording layer, and has a good dynamic balance. The purpose is to

[Means for Solving the Problems] That is, the present invention forms a recording layer on which information signals are recorded on a disk-shaped substrate having a central hole, and protects the recording layer with a protective substrate through a gap. In the optical disc, an annular inner protrusion and an annular outer protrusion provided on the protective substrate are brought into contact with the inner part and the outer peripheral part of the disc-shaped substrate where the recording layer is not formed, respectively, and the ring-shaped inner protrusion and the outer protrusion provided on the protective substrate are brought into contact with the inner part and the outer peripheral part where the recording layer is not formed. There is an optical disk characterized in that the gaps between the central hole and the inner protrusion and between the outer protrusion and the peripheral edge are filled with an adhesive and bonded together.

The present invention will be explained below based on the drawings.

FIG. 1(a) is a plan view that best represents the features of the optical disc of the present invention, and FIG. 1(b) is a sectional view taken along the line AA.

In the figure, the optical disc of the present invention has a recording layer 4 on which an information signal is recorded on a disc-shaped substrate (hereinafter referred to as a substrate) 1 having a center hole 10, formed in a strip shape concentrically with the center hole IO; The protective substrate 2 is provided with an annular inner protrusion 5 and an annular outer protrusion 6, and the protective substrate 2 and the substrate l are attached to the inner peripheral part 7 and the outer peripheral part 8 of the substrate l, where the recording layer 4 is not formed, respectively. The annular inner protrusions 5 and outer protrusions 6 are brought into contact and abutted to form a center hole IO formed between the protective substrate 2 and the substrate 1, the inner protrusions 5, the outer protrusions 6 and the peripheral edge 9.
An adhesive 3 is filled in each gap between the substrates, and the recording layer 4 on the substrate l is protected by the protective substrate 2 with the gap interposed therebetween.

In the present invention, the substrate 1 may be any material as long as it is transparent to the light used during recording and reproduction.For example, a resin such as polycarbonate (PC) or acrylic (PMMA) may be used.

The protective substrate 2 may be made of a material with good moldability, such as PC, ABS resin, etc.

Annular inner protrusion and outer side on the protective substrate.

The protrusions can be formed by vacuum forming, embossing, or the like. The inner protrusion and outer protrusion formed on the protective substrate also function as a spacer.

As the recording layer 4, low melting point metals such as Te and Bi, or compounds thereof, or organic dyes such as cyanine and polymethine, alone or in combination, are used. In addition, when the dye composition is used as a recording layer, it may contain a self-oxidizing resin such as nitrocellulose or a thermoplastic resin such as polystyrene or nylon.Additionally, a quencher or the like may be added to prevent oxidative deterioration of the dye. An agent may also be included.

The adhesive 3 is preferably one with low viscosity.

For example, adhesives such as polyester, epoxy, and epoxy acrylate are preferred, and the viscosity of the adhesive is usually 10
,000 cps or less, preferably 1,000 to 5.0
00 cps is desirable, and if it exceeds 10,000 CPs, the fluidity is poor and it becomes difficult to fill the gap between the substrate and the protective substrate, so it is not preferable.

In the optical disc of the present invention, a protective substrate is positioned and brought into contact with the substrate on which the recording layer is formed, and gaps are formed between the central hole and the inner protrusion and between the outer protrusion and the peripheral edge formed between the protective substrate and the substrate. It can be easily manufactured by pouring an adhesive into, curing, and bonding. When positioning the J board on the board, if necessary, as shown in FIG. It may be temporarily fixed to the substrate l by heat fusion, ultrasonic heating, or the like.

[Function] The optical disc of the present invention has annular inner protrusions and outer protrusions formed on the protective substrate at portions corresponding to the innermost periphery and the outermost periphery of one recording layer. By pouring adhesive into the gap between the center hole and the inner protrusion and between the outer protrusion and the periphery, curing and adhering it, it eliminates the adhesive from seeping into the recording area, prevents damage to the recording layer, and makes it even more dynamic. It becomes possible to obtain a well-balanced optical disc.

In other words, if the inner and outer protrusions of the protective substrate are in contact with or in close proximity to the inner and outer peripheries of the substrate, surface tension will cause the annular protrusions to form even if a low-viscosity adhesive is poured. The adhesive does not seep out into the recording area [Example] The present invention will be explained in more detail below with reference to Examples.

Example 1 Outer diameter 901mφ, inner diameter 15m layerφ, thickness 1.2mm
A recording layer having a thickness of 1,000 layers was formed on a substrate made of c by a spin code method. Outer diameter 90mm as a protective board
φ, inner diameter 15 φ, thickness 0.31 pc, @0. :law + 0.5 layer depth - inner and outer protrusions were formed, respectively. After temporarily fixing the protective substrate on the substrate by heat fusion, apply a polyester ultraviolet curing adhesive ( An optical disc was obtained by pouring UV100I (manufactured by Sony Chemical, viscosity: 1000 cps) using a dispenser, curing and adhering.

The thus obtained optical disc had no adhesive seeping into the recording area and had good dynamic balance.

Embodiment 2 FIG. 3 is an explanatory diagram showing a bonding method when a large number of optical discs of the present invention are simultaneously produced from one sheet. As shown in the figure, when manufacturing a large number of optical disks from one sheet, after aligning the entire sheet, temporarily fix the sheets at the positions of alignment marks 12a to 12d in the figure. A large number of optical discs can be obtained by injecting adhesive from the inlet, curing and adhering.

[Effects of the Invention] As explained above, according to the optical disc of the present invention, the protective substrate is provided with annular inner protrusions and outer protrusions, and adhesive is poured into the outer portions of the annular protrusions to bond them to the substrate.
It is possible to prevent the adhesive from spilling out into the recording area, prevent damage to the recording layer, and achieve a good dynamic balance.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view showing an example of the optical disc of the present invention, FIG. 1(b) is a sectional view taken along line AA, and FIG. 2 is a temporary marketed state of the protective substrate when manufacturing the optical disc of the present invention. and FIG. 3 are explanatory diagrams showing a bonding method when a large number of optical discs of the present invention are simultaneously produced from one sheet. l... Board 2... Protective board 3...
・Adhesive 4...Recording layer 5...Inner protrusion 6...Outer protrusion 7...Inner peripheral part
8...Outer peripheral part 9...Peripheral part
10... Center hole 11... Temporary fixing portions 12a-d... Positioning mark 13... Inlet

Claims (1)

[Claims] In an optical disk in which a recording layer on which information signals are recorded is formed on a disk-shaped substrate having a center hole, and the recording layer is protected with a protective substrate through a gap, an annular inner protrusion and an outer annular protrusion provided on the protective substrate are provided. The protrusions are brought into contact with the inner and outer circumferential parts of the disk-shaped substrate where the recording layer is not formed, and between the center hole formed between the protective substrate and the disk-shaped substrate and the inner protrusion, and between the outer protrusion and the peripheral edge. An optical disc characterized by being made by filling the gap between adhesives and bonding them together.