JPH0449177B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing digital signal recording and reproducing disks such as video disks, digital audio disks (eg, compact disks), still images, document files, and the like.

Conventional structure and its problems This type of digital signal recording/reproducing disk is
It is considered promising as an information medium due to its extremely high information density, low S/N ratio, and low noise.
It has been commercialized as a compact disc, which is a video disc or digital audio disc.

FIG. 1 shows an overview of a general digital audio disk. In this system, a PCM-converted digital signal is created as a concavo-convex pit array signal on a resin substrate, and this is reproduced by a semiconductor laser. In FIG. 1, 1 is the entire disk 2 is a resin substrate, 3 is a digital signal engraved on the resin substrate 2, 4 is a reflective film created on its surface, and 5 is a protective film coated on the surface of the reflective film 4. , 6 is a reproducing semiconductor laser beam irradiated from the reading surface of the disk 1.

In general, disks are manufactured using injection molding or injection molding.
A compression molding method is used.

FIG. 2 shows a conventional injection molding method for a digital signal recording/reproducing disk. FIG. 2a shows a front view of the device, and FIG. 2b shows a side view of the device.A molding machine 7 is equipped with a molding die 8, and a signal forming stamper 9 is provided therein. is created.

In the case of a compact disk, which is a digital audio disk, the diameter is large at 12 cm, so a large molding machine is required, and each molding machine has one mold and a stamper for signal formation, and only one resin substrate can be created. This has led to problems such as poor mass production and high equipment costs, leading to increased costs.

Purpose of the Invention The present invention solves the above-mentioned conventional problems, and is an inexpensive digital signal recording/reproducing disk which can save labor in equipment and is excellent in mass production by producing many disks with one molding machine. and its manufacturing method.

Structure of the Invention The present invention uses a plurality of independent signal forming stampers in one molding machine when manufacturing a disk in which pit rows are formed in the same standard as a compact disk on a resin substrate with a diameter of 5 cm to 12 cm. Then, the same number of independent resin substrates as the signal forming stampers are simultaneously molded by injection molding, compression molding, or injection/compression molding.

DESCRIPTION OF THE EMBODIMENTS FIG. 3 shows an embodiment of the digital signal recording/reproducing disk manufacturing apparatus of the present invention. FIG. 3a is a front view of the entire device, and FIG. 3b is a side view as seen from location A in FIG. 3a.

The molding machine 7 is provided with a molding die 10, and four signal forming stampers 11 are provided therein.
One resin is injection molded onto this, and four resin substrates are created at the same time. In this case, if the diameter of the disk to be produced is 6 cm, the size is 1/2 and the projected area is 1/4 of the 12 cm diameter of a normal compact disk. Therefore, a molding machine having the same mold clamping force as a molding machine for compact discs can mold four discs at the same time.

FIG. 4 shows a digital signal recording/reproducing disk obtained by the above embodiment. In this case, the signal area is 12.

For compact disks, the linear velocity is 1.2~
Since the pitch of a 1.4 m/s signal is 1.6 μm, if the linear velocity is 1.25 m/s and the diameter of the disc is 6 cm, it will be possible to play for about 7 minutes. In other words, traditional EP
The same amount of information that is recorded on the front and back sides of a vinyl record can be recorded on a 6cm diameter disk. The manufacturing method according to this embodiment is particularly advantageous for manufacturing such small-diameter disks.

Figure 5 shows a normal compact disk with a diameter of 12 cm. The signal area in this case is 13.

In this way, according to this embodiment, the smaller the disk shape, the more digital signal recording/reproducing disks can be made with the same conventional molding machine, which leads to mass production and cost reduction. can be achieved.

Effects of the Invention As described above, according to the present invention, a PCM-converted digital signal is converted into an uneven pit array with a pitch of approximately 1.6 μm and a reproduction linear velocity of 1.2 to 1.4 m/s, which is smaller than 12 cm in diameter and smaller than 5 cm in diameter. In a method for manufacturing a digital signal recording/reproducing disk formed on a large resin substrate and a reflective film and a protective layer formed on the resin substrate, a plurality of independent signal forming stampers are installed in one molding machine. By molding the same number of independent resin substrates as the signal forming stampers at the same time using injection molding, compression molding, or injection/compression molding, mass production of disks can be achieved and inexpensive digital signal recording can be achieved. Reproduction discs can be provided.

[Brief explanation of the drawing]

Figures 1a to 1c are a plan view, a sectional view, and a sectional view of a main part of a general digital signal recording/reproducing disk;
2a and 2b are front and side views of a conventional molding apparatus for manufacturing a digital signal recording/reproducing disk, and FIGS. 3a and 3b are a front view of an embodiment of the apparatus for manufacturing a digital signal recording/reproducing disk of the present invention. FIG. 4 is a plan view of a digital signal recording/reproducing disk obtained by the above embodiment, and FIG. 5 is a plan view of a normal compact disk. DESCRIPTION OF SYMBOLS 1... Disk, 2... Resin substrate, 3... Digital signal, 4... Reflective film, 5... Protective film, 7...
... Molding machine, 10... Molding die, 11... Signal forming stamper, 12... Signal area.

Claims (1)

[Claims] 1. A PCM-converted digital signal is formed as an uneven pit row with a pitch of approximately 1.6 μm and a reproduction linear velocity of 1.2 to 1.4 m/s on a resin substrate smaller than 12 cm in diameter and larger than 5 cm in diameter. In a method of manufacturing a digital signal recording/reproducing disk in which a reflective film and a protective layer are formed on a disc, a plurality of independent signal forming stampers are arranged in one molding machine, and injection molding, compression molding, or injection/compression is performed. A method for manufacturing a digital signal recording/reproducing disk, characterized in that the same number of the signal forming stampers and each of the independent resin substrates are simultaneously molded by a molding manufacturing method.