JPS60149422A - Manufacture of digital signal recording and regenerating disc - Google Patents

Abstract

PURPOSE:To obtain a faultless disc having good shape and excellent optical characteristics by providing a white ointment-like substance composed primarily of noncrystalline solid hydrocarbon between the back face of a stamper and a mold. CONSTITUTION:A white ointment-like substance composed primarily of a noncrystalline solid hydrocarbon or a substance 16 composed primarily of a hydrocarbon of methane series (e.g., high-melting paraffin, etc.) is provided between the back face of a tamper 7 and the mirror face 8 of a mold. When a resin flows from an injection port 13, the resin uniformly flows on the stamper 7 to obtain faultless resin base plates 17 having good double refractive index.

Description

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

Conventional structure and its problems This type of digital signal recording/reproducing disk is considered to be promising as an information medium due to its extremely high information density and large SIN, da23, and inamino clean range, and has been widely used as a video medium. It has been commercialized as a disc or digital audio disc.

FIG. 1 shows an overview of a compact disc, which is a common digital audio disc. In this method, a PGM-converted digital signal is recorded on a resin substrate as a signal in the form of a pit train, 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 in the form of a pit row, 4 is a reflective pancreas formed on its surface, 5 is a protective film coated on the surface of the reflective pancreas 4, and 6 is a This is a semiconductor laser that is irradiated from the reading surface of the disk 7.

The disk is generally made by a molding process shown in FIG. Resin is molded onto the digital signal creation stamper 7 shown in FIG. 2(a), and the stamper 7 shown in FIG. 2(b) and (C)
In the process shown in FIG. 1, the digital signal is transferred and the resin substrate 2 is created. Thereafter, the digital signal recording/reproducing disk shown in FIG. 1(C) is produced through sequential steps.

3 <-- A conventional stamper is generally a Ni plate made by electroplating, and has a thickness of 0.2 to 0. (It is as thin as 0.3 m, and there are problems such as warping, waviness, and uneven thickness that are undesirable in terms of molding.

FIG. 3 shows a case in which a disk is formed by relying on such a stamper. Figure 3(a) shows a cross-section of the molding process, and shows a stamper with many warps, undulations, and uneven thickness.
7 is held by a portion 9 that partially contacts the casting surface 8 of the molding die and holds the inner periphery of the stamper, and a portion 1o that holds the outer periphery of the stamper. Reference numeral 11 indicates a fixing part of the molding die, and reference numeral 12 indicates an outer circumference ring forming the outer circumference of the disk.

Resin is injected from the injection port 13, and a resin substrate is molded in the space 14 of the mold. In this case, as shown in FIG. 3 (kl), the resin substrate 16 has many warps, undulations, and thickness unevenness in its shape, and moreover, the back surface of the stamper 7 and the mirror surface part 8 of the molding die are not in contact with each other. Due to imperfections, heat conduction is poor and the temperature distribution of the methamper causes uneven flow of resin on the stamper, resulting in defects such as molding whiskers, silpers, IJ-ri, etc. However, there were problems such as deterioration of optical properties such as increased birefringence.

OBJECTS OF THE INVENTION The present invention solves these problems and provides a method for manufacturing a digital signal recording/reproducing disk with a good disk shape and excellent optical characteristics without molding defects. be.

Structure of the Invention The present invention provides a material mainly composed of a non-crystalline solid hydrocarbon, and a white ointment-like material containing the same, between the back surface of the stamper and the molding die in contact with the stamper. This is a method of manufacturing a digital signal recording/reproducing disk formed by providing a substance W whose main component is a methane group hydrocarbon.

DESCRIPTION OF THE EMBODIMENTS FIG. 4 shows an embodiment of a method for manufacturing a digital signal recording/reproducing disk according to an embodiment of the present invention. Here, a case where a disk is injection molded is shown in a cross-sectional view.

5\ku-a Figure 4(a) A white ointment-like substance containing non-crystalline solid hydrocarbon as a main component is placed between the back surface of the stamper 7 and the mirror surface part 8 of the molding die that is in contact with it. The case where petrolatum 16 is provided is shown. Petrolatum forms a thin film of several micrometers to several tens of micrometers between the back surface of the stamper and the mirror surface of the mold, and has good thermal conductivity, so the heat conducted from the mirror surface of the mold is transferred to the stamper 7. is conducted uniformly. Therefore, if the resin flows from the injection port 13, the stamper 7
Since the resin flows uniformly over the resin substrate 17'f, it is possible to create a resin substrate 17'f with no molding defects and with a good birefringence. The petrolatum also acts as a cushion against the impact of the stamper during molding, and as shown in Figure 4 (+), the shape of the resin substrate 17 creates a good disk with little warpage, waviness, or thickness unevenness. can do.

Between the back surface of the stamper 7 and the mirror surface part 8 of the mold,
A similar effect can be obtained by providing a substance containing a methane group hydrocarbon as a main component (for example, high separation point paraffin).

6.

Effects of the Invention As in the present invention, a substance containing an amorphous isotropic hydrocarbon as a main component and a white ointment containing the same are placed between the back surface of a stamper for creating a digital signal and the mirror surface part of a molding die. W'
If a digital signal recording/reproducing disk is molded with x provided, a digital signal recording/reproducing disk with little warpage, waviness, or thickness unevenness, no molding defects, and excellent optical properties such as birefringence can be obtained.

[Brief explanation of drawings]

Figures 1 (a), (b), and (Q) are a plan view, cross-sectional view, and main part cross-sectional view of a general digital signal recording/reproducing disk, and Figures 2 (a), (b), and (C) are 3(a), (b) are sectional views showing the manufacturing process of a conventional digital signal recording/reproducing disk, and FIG. 4(a),
(b) is a sectional view showing an example of a method for manufacturing a digital signal recording/reproducing disk according to an example of the present invention. 1...Disc, 2...Resin substrate, 3
・・・・・・D7.1. = digital signal, 4... reflex waist, 6... protection 4 7.
...Stambar - 18...Mirror surface part of the intermediate carving mold, 9.
...Inner periphery holding part of stamp bar, 1o...Outer periphery holding part of stamper, 11...Fixing part of mold, 12.
White: outer ring, 13... injection port, 14...
. . . Space of mold, 16. . . White ointment-like substance containing amorphous hydrocarbon as a main component, 17 . . . Digital signal recording/reproducing disk. Name of agent: Patent attorney Toshio Nakao 1 person, 1 person Tsuru
Figure man 2 figure rod 3 figure 13 914 // 12

Claims (1)

[Claims] Between the back surface of the stamper for digital signal creation and the mirror surface of the molding die that comes into contact with it, there is a substance whose main component is amorphous solid hydrocarbon, a white ointment-like substance containing this substance, or methane. 1. A method for manufacturing a digital signal recording/reproducing disk, characterized in that the disk is formed using a substance whose main component is a columnar hydrocarbon.