JPH02160517A - Manufacture of grooved substrate for optical disk - Google Patents

Abstract

PURPOSE:To improve accuracy in thickness by a method whereby a pressing plate is placed on a resin hardened by ultraviolet rays and applied on a stamper thereby to spread said resin, so that said pressing plate is provided with a resin layer having the surface of said stamper transferred onto a smooth part of the lower surface thereof, and said resin layer is aligned with the surface of said stamper. CONSTITUTION:A resin 4 which is hardened by ultraviolet rays is applied onto a stamper 3 which is supported and reinforced by a backing plate 1 via an adhesive layer 2. Then, a pressing plate 5 made of glass is placed to compress the resin 4. At this time, the side face of the pressure plate 5 and that of the plate 1 are marked with respective marks 10, 11. The resin 4 is hardened through irradiation of ultraviolet rays. As a result, the pressing plate 5 is formed with a resin layer. A resin 8 which is hardened by ultraviolet rays is applied on the stamper 3, onto which is placed a transparent substrate 7. Subsequently, the pressing plate 5 is placed so that the marks 10, 11 are agreed, and pressed so as to spread the resin 8. After setting of the resin 8, the pressing plate 5 is removed. Thus, a grooved substrate 9 is obtained. According to this method, the thickness distribution of the stamper 3 and pressing plate 5 is reversed, thereby compensating for each other. Therefore, the parallellism is uniform, and variations in thickness is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a grooved substrate for an optical disk with excellent thickness accuracy.

[Conventional technology]

Methods for manufacturing grooved substrates for optical disks include integral molding methods such as injection molding, and so-called PhotoPot method, in which the grooves on the stamper surface are transferred to a transparent substrate using ultraviolet curing resin.
There is a lymer method (2P method). Among these, the 2P method is reliable because it has good transferability from the stamper and is easy to apply to substrates such as thermosetting plastics and glass. It is used as a method for manufacturing grooved substrates with excellent texture and quality.

To explain the process of the 2P method, as shown in Fig. 3, an ultraviolet curable resin (4) is applied onto a stamper (3), and then a transparent flat plate (7) and a pressing plate (5) are applied on top of the stamper (3). After rolling the resin (4) by pressing with an appropriate pressure, the resin (4) layer is cured by irradiation with ultraviolet rays, and the resin (4) layer and the stamper (3) are separated. Manufactured by Since the stand bar (3) used at this time is generally thin, it is lined with a rigid banking plate (1). Examples of this method include a chatting method using magnetic force, vacuum, etc., and a method of directly bonding plates with adhesive. With either method, it is impossible to completely eliminate variations in the total thickness of the plate and stamper, or waviness on the stamper surface, and it is impossible to make the parallelism between the clamping plate and stamper uniform over the entire area. Because of this difficulty, even if a transparent substrate with a uniform thickness is used, it is one of the major causes of thickness variations.

[Problems to be Solved by the Invention] Therefore, the present inventor paid attention to the fact that the parallelism between the pressure plate and the stamper greatly affects the thickness accuracy of the grooved substrate, and as a result of intensive research, the present invention was developed. The goal was to manufacture grooved substrates with extremely high thickness accuracy using a simple method.

[Means to solve the problem]

That is, in the present invention, an ultraviolet curable resin is applied on a stand bar in which an information recording guide groove is formed, a transparent substrate is placed on top of the stanbar, and the resin is cast by pressing the substrate with a transparent pressing plate. In the method for manufacturing a grooved substrate for an optical disk in which the resin is cured by irradiating ultraviolet rays from above the clamping plate, the clamping plate is placed directly on the ultraviolet curable resin coated on the stamper. Pressing with a transfer resin layer in which resin is cast, the resin is cured by irradiation with ultraviolet rays from above the pressing plate, and the resin layer and stamper are peeled off to transfer the stamper surface to the smooth lower surface of the pressing plate. A method for producing a grooved substrate for an optical disk, characterized in that a plate is produced, and during the production of the grooved substrate, the transfer resin layer of the pressing plate is aligned with the surface of a corresponding stamper. .

Hereinafter, specific examples of the present invention will be explained in detail with reference to the drawings.

As shown in FIG. 1, first, an ultraviolet curing resin (4) is applied via an adhesive layer (2) onto a stamper (3) backed and reinforced with a backing plate (1). Subsequently, a glass clamping plate (5) is placed and clamped by applying appropriate pressure. At this time, in order to position the clamping plate and stand bar, there are marks (
IIIl, (10) is applied, the resin is cured by irradiation with ultraviolet and external rays, and a clamping plate on which a transfer resin layer is formed is obtained.The resin used here is not particularly limited, but the curing It is preferable that the hardness of the latter is the same as or lower than that of the substrate.

Next, a grooved substrate is manufactured using the pressing plate having the transfer resin layer 02). First, as shown in FIG. Then, a transparent substrate (7) is placed thereon. Next, use the stamper (
Mark (II) on the backing plate (1) in 3)
) and the mark OI made on the side of the clamping plate (5), place the clamping plate (5) on it, and press it to cast the resin (8). Then, the resin (8) is cured,
The grooved substrate (9) is obtained by peeling. In addition, standby (3)
It is preferable that the pressure plate (5) is always installed at the same position relative to the pressure device such as a cylinder.This means that the positional relationship when the transfer resin layer a is provided on the pressure plate (5) is By matching them, the thickness distributions of the stamper (3) and the clamping plate (5) are in an inverse relationship and do not compensate for each other, resulting in uniform parallelism and eliminating variations in thickness accuracy. Because it can be done.

As a method for this, it is also effective to attach the aforementioned marks 0ω and aO.

[Effect]

According to this method, the clamping plate and the stamper have the same surface precision, so that a substantially parallel space can be formed between the clamping plate and the stamper during clamping. Therefore, since the transparent substrate follows the stamper surface, the thickness of the groove transfer layer becomes uniform, and a uniform grooved substrate can be obtained without impairing the thickness accuracy of the original substrate.

Example surface hardness (pencil hardness) after curing on stamper backed with adhesive on backing plate with marks on side
Apply an ultraviolet curable resin such as HB, place a glass clamping plate with marks on the side on top of it with the marks on the plate and clamping plate aligned, and roll and harden the resin. As a result, a pressing plate with the stamper surface transferred to the lower surface of the pressing plate was obtained.

Next, an ultraviolet curable resin with a viscosity of 150 cps at room temperature is applied onto the stamper, and an epoxy resin-acid anhydride cured product (surface hardness H1 thickness I, 15±0.03 m
) was made into f2, and the plate on the stamper side and the press plate were pressed together while the mark positions were slightly bent, and the resin was rolled and cured to produce a grooved board. In the same manner, 100 grooved substrates were manufactured and the variation in thickness was measured. The results are shown in Table 1.

Comparative Example 100 grooved substrates were manufactured using the same equipment and materials as in the example except that a normal glass clamping plate was used, and the variation in thickness was measured. The results were as shown in Table 1.

Table (Note) a) The current thickness was measured at 4 locations in the radial direction and 4 locations in the circumferential direction, for a total of 16 locations on the - sheet.

b) The defective rate of grooved substrates is that the thickness variation with respect to the average thickness of 100 sheets is ±0°03IIl for all measured locations.
If it was within 11, it was considered to be passed, and otherwise it was judged to be defective.

c) 2Pji thickness was determined by observing the cross section of the substrate at the thickness measurement position described above, measuring the thickness of the groove transfer layer, and determining the average value.

〔Effect of the invention〕

According to the present invention, since the parallelism between the pressing plate and the stamper surface is always constant, the grooved substrate produced has less uneven thickness, and is extremely useful as a method for manufacturing grooved substrates for optical disks. .

[Brief explanation of the drawing]

Fig. 1 shows the step of transferring the stamper surface to the lower surface of the pressing plate in the present invention, Fig. 2 shows the manufacturing process of a grooved substrate using the pressing plate obtained in Fig. 1, and Fig. 3 shows the process of manufacturing a grooved substrate using the pressing plate obtained in Fig. 1 is a diagram showing a manufacturing process of a conventional grooved substrate. Patent applicant: Sumitomo Bakelite Co., Ltd. 9-groove Banmin

Claims (1)

[Claims] (1) An ultraviolet curing resin was applied onto the stamper in which the information recording guide groove was formed, a transparent substrate was placed on top of the stamper, and the resin was cast by pressing the substrate with a transparent pressing plate. rear,
In a method for manufacturing a grooved substrate for an optical disk in which the resin is cured by irradiating ultraviolet rays from above the clamping plate, the clamping plate is placed directly on the ultraviolet curable resin coated on the stamper and the resin is cast. , producing a clamping plate having a transfer resin layer in which the resin is cured by irradiating ultraviolet rays from above the clamping plate, and the resin layer and the stamper are peeled off to transfer the stamper surface to the smooth lower surface of the clamping plate; A method for producing a grooved substrate for an optical disk, characterized in that, during the production of the grooved substrate, the transfer resin layer of the pressing plate is aligned with the surface of a corresponding stamper.