JPH087536Y2 - Optical recording disc - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an optical recording disk, and more particularly to a structure of a recording film carrying side surface of the optical recording disk.

<Prior Art> An optical recording disk is a disc-shaped substrate and a recording film having a composition of Te-C or Tb ₂₅ Fe ₇₀ Co ₅ or the like, which has a diameter substantially the same as that of the substrate and is adhered to the substrate. Composed of and.

FIG. 1 is a plan view of an optical recording disk 1 which has been conventionally used, viewed from the surface of a recording film carrying side. The surface on which the recording film is supported is generally divided into an inner peripheral flat portion 2, an information recording portion 4, and an outer peripheral flat portion 6 from the center of the optical recording disc 1 toward the outer side in the radial direction, and the information recording portion 4 is a recording area. The inner and outer flat portions are non-information recording areas usually called mirror portions. However, in the conventional optical memory, as shown in FIG. 2, since the substrate 8 and the recording film 10 are simply pasted together in a planar manner, repeated heat cycles due to changes in the environmental temperature, etc. The film is likely to be peeled off on the information recording portion 4. Once such film peeling occurs, information reading from the recording film by optical means is partially impossible, and the optical memory is practically unusable.

<Object of Invention> Therefore, an object of the present invention is to prevent film peeling due to thermal cycling in an optical recording disk. Another object of the present invention is to further strengthen the bonded state of the substrate and the recording film of the optical recording disk.

<Outline of the Invention and Operation and Effect> The present invention has a recording film for optically recording and optically reading on a disk-shaped substrate, and the recording film has an inner peripheral side. And a non-information recording area formed on the outer peripheral side and an information recording area formed between the inner peripheral side and outer peripheral side non-information recording areas. Tracking grooves or grooves and pit rows are formed concentrically or spirally at a pitch of 1 to 5 μm on the surface of the recording film formation side. Grooves and / or pit rows having the same size as the groove and / or pit rows are formed on the surface of the substrate on which the recording film is formed.
With a pitch of 5 μm, concentric circles or spirals,
The optical recording disk is formed over a radial width of 5 mm or more, and prevents the recording film from peeling off due to a thermal cycle.

The unevenness of the grooves and pit rows formed in the non-information recording area is
The bonding between the substrate and the recording film is further strengthened, which prevents the recording film from peeling off from the substrate due to thermal cycles such as environmental temperature changes.

<Description of Preferred Embodiment> An embodiment of the present invention will be described in detail with reference to FIGS. FIG. 3 is a plan view of the optical recording disk 1 as seen from the surface on the recording layer carrying side, and FIG. 4 is an enlarged sectional view through the center of the optical recording disk. The optical recording disk 1 is preferably made of polycarbonate. Disk-shaped substrate 8 and a recording film 10 deposited on the surface thereof. The optical recording disc 1 is divided into an inner peripheral flat portion 2, an annular information recording portion 4 and an outer peripheral flat portion 6 from the center toward the outer side in the radial direction. An uneven portion 12 is provided in contact with the portion 4. These portions can be formed by forming a predetermined uneven pattern at the same time when the substrate 8 is injection-molded by a mold and then depositing the recording film 10 described above.

As shown in the figure, the concave and convex portions 12 are arranged in the circumferential direction of the optical recording disk 1 at a pitch of 1.0 to 5 .mu.m, either spirally or concentrically as shown. This uneven part
Reference numeral 12 is substantially the same as a spiral or concentric groove or pit row in the information recording portion 12. In addition, the range where the concave and convex portion 12 is formed is the information recording portion 4 of the optical recording disc 1.
In at least one part adjacent to
It is formed in the range of the radial width of 0.5 mm, whereby the bonding between the substrate 8 and the recording film 10 is further strengthened.

The effect of strengthening the bonding between the substrate and the recording film by providing the groove 12 on the substrate 8 of the optical recording disk was also verified in the following experiment.

Experiment 1 1) Content: The inner diameter of 15 mm, the outer diameter of 130 mm, and the thickness of 1.2 mm, the information recording area from the inner diameter of 50 mm to the outer diameter of 120 mm on the polycarbonate substrate surface has a depth of 1.6 μm and a depth of 0.
A spiral groove of 07 μm is formed, on which Tb ₂₅ Fe ₇₀ Co is formed.
A recording film of ₅ compositions is formed to form a recording medium, and the recording medium is kept at a temperature between + 80 ° C and -20 ° C for 100 cycles.

2) Result: Film peeling occurred only in the range of inner diameter 50.6 mm or less and outer diameter 119.2 mm or more.

Experiment 2 1) Content: Depth in the same information recording area on the substrate surface of the same optical recording disk as in Experiment 1, instead of the spiral groove.
Pits of 0.1 μm and length of 2 μm are formed at the same pitch and held for 100 cycles under the same temperature.

2) Result: Film peeling occurred in the recording film only in the almost same range as in Experiment 1.

On the other hand, for comparison, the same experiment was carried out with no recording film having a spiral groove or pit in the information recording part and simply pasting the recording film on the substrate surface as usual.
Film peeling occurred over the entire area of the recording film.

As confirmed by Experiments 1 and 2, when a disc having a large number of fine spiral grooves or pit rows was tested under severe environmental conditions, peeling occurred only in the range of 0.6 to 0.8 mm on the inner and outer circumferences. Nothing more than. Under normal environmental conditions, if a spiral groove or pit row or a concentric groove or pit row equivalent to this is formed in the radial width range of 0.5 mm or more, the peeling that progresses from the outside of the inner and outer circumferences has a groove. It can be seen that it can be completely prevented from reaching the inside of. When this is applied to an actual optical disc, the inner and outer peripheral flat portions of the information recording portion are 0.5 mm in the flat portion.
By forming a spiral groove or pit row or a concentric groove or pit row equivalent to the spiral groove or pit row in the above radial width range, it is possible to completely prevent the peeling progressing from the outside of the flat portion from reaching the information recording portion. Is clear.

Actually, the tracking groove of the spiral groove is provided in the range of the inner diameter of 50 mm to the outer diameter of 120 mm to form the recording area,
When the same groove or the pit row was provided on both sides of the inner and outer circumferences over a width of 0.5 mm in the radial direction,
No peeling was observed in the recording area even by the 100-cycle thermal cycle test between + 60 ° C and -20 ° C.

On the other hand, instead of the pit row on the inner and outer circumferences of the recording area,
The recess row was arranged. The recesses had a depth of 10 μm and a diameter of 20 μm, were arranged on the circumference at intervals of 40 μm, and the recess rows were arranged 20 times inside and outside the recording area. The distance between the adjacent concave portions was 40 μm between the adjacent circumferences, and the checkerboard pattern was arranged. The checkered area width is about 0.6 mm. As a result, in the thermal cycle between + 60 ° C and -20 ° C, peeling of the recording area was recognized after 80 cycles.

In the present invention, since these concave and convex portions are present on the same surface as the information recording portion, simultaneous injection molding of these portions is possible and work efficiency is extremely good.

Although the present invention has been described above based on the embodiments, it should be noted that many modifications can be made within the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a plan view of a conventional optical recording disk. FIG. 2 is a sectional view of FIG. 1 taken along the line AA. FIG. 3 is a plan view similar to FIG. 1 of the optical recording disk of the present invention. FIG. 4 is a sectional view of FIG. 3 taken along the line BB. Explanation of symbols 2 …… Inner peripheral flat portion 4 …… Information recording portion 6 …… Outer peripheral flat portion 10 …… Recording film 12 …… Uneven portion 8,14 …… Substrate

Claims (1)

[Scope of utility model registration request] 1. A recording film for optically recording and optically reading on a disk-shaped substrate, the recording film being formed on an inner peripheral side and an outer peripheral side thereof. The recording medium has a non-information recording area and an information recording area formed between the inner peripheral side and outer peripheral side non-information recording areas, and the surface of the substrate on the recording film forming side below the information recording area of the recording film. Tracking grooves or the grooves and pit rows are formed concentrically or spirally at a pitch of 1 to 5 μm, and further, on the recording film formation side of the substrate below both non-information recording areas of the recording film. Grooves and / or pit rows of the same size as the groove and / or pit rows are formed on the surface in an amount of 1 to 5
0.5m in concentric circles or spirals with a pitch of μm
An optical recording disk that is formed over a radial width of m or more and that prevents film peeling of the recording film due to thermal cycling.