JPS5894149A - Manufacture for master disc for preparing optical interference type guide groove of optical disc - Google Patents

Abstract

PURPOSE:To form an optical interference type guide groove with high precision and excellent accuracy, by irradiating two-luminous-flux laser light on a photo resist layer formed on a base, recording interference fringes and developing the recording. CONSTITUTION:A photo resist master disc 10 is formed by forming a photo resist 10b on a glass base 10a. A laser light from a light source 5 is split into two luminous fluxes at a half mirror 6, the two luminous fluxes are made divergent by using mirrors 7a, 7b and lens systems 8a, 8b, the two fluxes are irradiated to the photo resist 10b with a cross angle theta to record concentric interference fringes. Through the specified development, unevenness in response to the strength of light of the interference fringes can be formed. In case of the irradiation, the master disc 10 is fixed on a rotary stand 11, a mask 12 having a slit shaped window is fixed along the radial direction and the rotary stand 11 is rotated.

Description

[Detailed Description of the Invention] Regarding the MA method for original plates, more specifically, it is a guide groove that has excellent precision and is easy to detect by using interference fringes obtained by interfering with high coherence light such as laser light. The present invention relates to a method for manufacturing a master plate for optical disc manufacturing, which has easy random access and is suitable for mass production.

The optical recording method is an excellent recording method that can increase the recording density by more than an order of magnitude compared to the all-in-one recording method.
In order to record specific information at a predetermined position and to perform detection, a marker indicating the recording position r is required.

When there is no marker, the accuracy of the position of the written information can only be determined by the accuracy of mechanical positioning, and therefore it is difficult to record to any position and play back from that position, and to maintain the written information (additions, deletions and changes). etc.) becomes impossible and is not suitable for so-called random access.

Also, when recording and playing back information using one optical disc containing one seed tree information v, it is better to arrange the recording areas concentrically than on a spiral like a record disc (recording board for music, etc.). It is also easy to distinguish between information groups. However, in order to provide optical interference type guide grooves Y, which are markers for concentric recording and reproduction, on the original plate, conventionally, a laser beam is used to create a wire one by one on which a photoresist or the like is formed on the surface. Since each circle Y was exposed and then developed, it was inefficient, and the pitch between adjacent circles each day had to be determined by mechanical precision.

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional vvA, and to create an optical interference type guide groove Y that is efficient in manufacturing and has excellent precision by utilizing interference of laser light. The present invention discloses a method for producing an original plate that allows the following. On the contrary, the present invention is for producing an optical interference type guide groove of an optical disc, characterized in that a photoresist layer formed on a substrate is irradiated with two beams of laser beams to record interference fringes Y, and then developed. This relates to a method for manufacturing original plates.

The present invention will be explained in detail below.

The type of optical disc suitable for the present invention includes material, recording and
Principle of regeneration V1. ! However, in consideration of mass production, it is preferable to use a thermoplastic synthetic resin sheet or plate as the base, and as the optical recording layer, a thin film of a low melting point metal such as Te, Bi, In, Pb, or a laminate of such thin metal films. .

Next, we will discuss the optical interference type guide groove provided on the surface of the optical disk to indicate the recording position Y during optical recording and reproduction. As schematically shown in FIG. They are arranged concentrically as shown in the figure. This is a partial longitudinal sectional view showing a shape Y, and the optical interference type guide groove 1 has a convex top 3 and a concave bottom 4 which are flat and parallel to the base body. In FIG. 2, the width of the convex portion 3 in the left-right direction in the drawing is 05 to 2 μl in actual use, and the width of the concave portion is similarly (preferably 15 to 2 μl, but not limited to this).

In addition, the length from the bottom of the concave part to the top of the convex part, that is, the depth of the optical interference type guide groove, is Vi (1, 1 to 10 degrees is possible, but the search for the optical interference type guide groove is based on records and It has a close relationship Y with the wavelength of the laser light used for reproduction, and if the wavelength vJ of the laser light used is 2/4, λ4, etc., it is desirable.

Optical interference guide groove like the one above! When an optical disk having a laser beam Y is irradiated in a spot shape with a required size, the light reflected from the top of the convex portion of the guide groove and the light reflected from the bottom of the concave portion occur as described above, making it difficult to detect the recording position. It can be classified as a genus.

A method of manufacturing an optical disc having the optical interference type guide groove as described above will be described next.

The fifth factor and FIG. 4 are schematic diagrams showing one embodiment Y of the present invention.

First, a photoresist solution Y is coated on an appropriate flat substrate 10a such as glass by spinner coating to form a photoresist 10bl, and a photoresist original plate 10v is applied.
Form. The photoresist 10b may be of positive type or negative type. Next, as shown in Figure 3,
Laser light Y emitted from the laser light source 5] 1- Split into two beams by a mirror and reflected by mirrors 7a and 7b 2
Lens systems 8a and 8b illustrated as a set of 71 convex lenses
When the photoresist is irradiated with the two light beams at an angle of -0 intersection Y after both of the two light beams are made into divergent lights using Y, concentric interference fringes of light with a pitch of d determined by the relational expression λ 31nlT are generated. A photoresist original plate ID%-vacuum teyac etc. is fixed on the same rotation table 11 in the irradiation gland as described above, and a slit-shaped window is formed in the radial direction of the original plate on the photoresist II plate. By fixing the mask 12 close to each other and performing irradiation while rotating the turntable 11, concentric interference fringes are recorded on the photoresist layer.
By performing a predetermined development process, irregularities corresponding to the intensity of light in the interference fringes g2 are formed.

In the above manufacturing method, the depth of the optical interference type guide groove is determined only by the resist layer 4, but it is also possible to make the depth even shallower by controlling the development. or,
It is better for the slit width of the mask to be narrow, and if it is wide, the accuracy of the interference fringes recorded on the photoresist will be impaired, so it is preferably about α1u to IDJEjl.

In the embodiment described above, the photoresist original plate is rotated, but recording can also be carried out by a method in which the photoresist original plate is fixed as described below.

Figure 1 is a schematic diagram showing another embodiment of the present invention,
The radar light emitted from the laser light source 5 is transmitted to the eight-point mirror 6.
splits into two beams g: one beam is sent to mirrors 7a and 7b.
After passing through the lens system 8, the beam is made into parallel light, and then guided to a photoresist original plate 10 consisting of a photoresist (m10b) and a substrate 10.The other light beam is made into a diverging light by a convex mirror 9, and then guided to the photoresist original plate 10, where both Interference fringes occur due to interference between the two. However, in this actual and embodiment, the intersection angle - is the intersection angle of two light beams at any point on the photoresist original plate ≦ 2, so I becomes smaller toward the center of the photoresist plate 1, and therefore, the interference fringes become smaller. The spacing tends to be so thick that it covers two sides of the center C of the photoresist plate.

As mentioned above, both of the above aspects of the present invention are more efficient than the conventional method of exposing one line at a time, that is, one circle at a time, and the precision of concentric circles is excellent. If the laser light source for exposure is fixed, A is constant, and - means that there is no backlash once the exposure device is fixed, so it is not affected by mechanical precision and has good exposure. and a secondary plate can be obtained.

[Brief explanation of the drawing]

1 and 2 have an optical interference type guide groove. 1・・・・・・・・・・・・・・・−・・Optical interference type guide groove 2・・・・・・・−・・・Optical disc 3・−・・−・・・・・・・・・・・・Top 4 of convex part
・・・・・・・・・・・・・・・・・・Bottom of recess 5・
・・・・・・・・・・・・・・・・・・Laser light source 6・
・・・・・・・・・・・・・・・・・・ Half mirror 7,
7a, 7b... Mirror 8a, 8b... Lens system 9...
......Convex mirror 10...
......Photoresist original plate (1o &...M board, 10b...photoresist) 11...Rotary table 12...
・・・・・・・・・・・・Mask Fang 1 Fang 8 Fang 4 Fang 4 Said δ

Claims (1)

[Claims] (1) A method for producing a master plate for producing an optical interference type guide groove for an optical disc, characterized by recording interference fringes Y by irradiating two beams of laser light onto a photoresist layer formed on a substrate, and then developing. .