Formation of master disk for optical disk

[Detailed Description of the Invention]

(b) Field of the Invention Especially this invention relates to the laser exposure method of the resist film applied on the glass substrate about the preparation method of the master original recording for optical discs. (Ro) PRIOR ART It is the former as a method of creating the guide rail of an optical disc, for example, a magneto-optical disc, and a write once optical disk, Resist is applied on a glass substrate and the resist film is exposed by laser, The method of creating an uneven part to a resist film, transferring the uneven part by Electroforming, creating La Stampa, transferring the uneven part of La Stampa by fabrication, and creating the guide rail of a plastic substrate is taken by developing it. And according to [ this guide rail size is standardized in the standardization committee of ISO recently and ] that draft standard, in the case of grouped lacking, it is, The pit shape of the header part on which the guide rail has recorded beforehand 1.2 - 1.3 micrometers in width, a depth of 880-1O0 n, and the address signal serves as a 0.3~0.5-micrometer depth of 80~130 nm in width from a point of signal quality. That is, in the case of grouped lacking, it is necessary to create a broad guide rail and a narrow pit. (C) In time, a flute width is determined as Object of the Invention mainly with the spot diameter of laser, and the spot diameter is controlled by the numerical aperture of an object lens, or intensity of laser power. It is not easy to carry out and to form the exposure belt of 0.3~0.5 micrometer of Radiation and an exposure belt with a width [ - ] of 1.2~1.3micro with sufficient contrast by one laser beam with - rudder. Then, the invention-in-this-application person has already applied for the method of arranging a plurality of laser beams in the radial direction of a disk, and forming a broad exposure belt (Showa 62 patent application No. 208948). However, it is although an exposure belt is formed with sufficient contrast in this method at best [ accuracy ] again, When making the disk radius method move a laser beam, if the movement magnitude (pitch) has unevenness, when variation is produced and developed to the width of an unexposed belt, unevenness will arise to the width of the land corresponding to an unexposed belt, and there is a problem that the homogeneity of land height is not maintained. In the present invention, it was made in consideration of such a situation. Therefore, the thing for which a resist film is irradiated with the laser beam which has a prescribed interval in the radial direction of a point disk, and an unexposed belt is secured with the interval, Even if a pitch changes at the time of movement of a laser beam, width of an unexposed belt does not change, and a preparation method of master original recording for optical discs which can obtain a broad exposure part belt is provided. (D) Means for solving problem In the exposure process of the resist film [ invention / this ] at the time of creation of the master original recording for optical discs, It has the 1st and 2nd laser beams in the resist film on a substrate, has a prescribed interval in the radial direction of an optical disc, and glares simultaneously, The above-mentioned prescribed interval is kept and two above-mentioned laser beams are moved to the radial direction of an optical disc so that the 1st and 2nd exposure belt may be formed, respectively, next a part of 1st laser beam may overlap some optical belts in the 21st, It is a preparation method of the master original recording for optical discs forming the broad exposure belt consisting of the 1st and 2nd exposure belt, irradiating with the 1st and 2nd laser beams simultaneously, repeating this work successively, and securing the non-exposing belt of the width corresponding to the above-mentioned prescribed interval. (Ho) OPERATION Since the 1st and 2nd laser beams have a prescribed interval in the radial direction of an optical disc and it is simultaneously irradiated with them, the unexposed belt of the width determined with the prescribed interval is formed. Since a part of 1st laser beam with which some formed 2nd exposure belts are irradiated at the next polymerizes, a broad exposure belt is formed. (What) EXAMPLE Hereinafter, based on the example shown in a drawing, this invention is explained in full detail. This invention is not limited by this. Drawing 1 is a composition explanatory view for which the schematic structure of a laser optics system applied to one example of this invention is shown, and, as for l!, as for a reflector and 14.15, a laser device and 12.18 are [ an optical deflector and +7 ] 172 wavelength plates an optical modulator and 16 a beam spree pig and 13.19. In such composition, it is discharged from laser device 11 and the laser beam of one r This is divided into two laser beams 4.5 by splitter 12. And laser beam 4 which passed along optical RtFII machine I4 and optical deflector 16, and laser beam 5 which was reflected in reflector 13 and reflected in reflector 19 through optical modulator 15, and l / 2\Il length board 17 are together put again by beam splitter 18, and enters into object lens 3. Drawing 2 is a perspective view showing the exposure state of the resist film of * at the time of the master original recording creation for optical discs, Drawings (a) (a) 3 and 4 are partial expanded sectional views showing each process of the exposure work shown in Drawing 1, and Drawings (b) (b) 3 and 4 are top views of the original recording portion corresponding to Drawing 3 (a) and Drawing 4 (b), respectively. In these figures, it is the resist film by which l was applied to the disk-like glass substrate and 2 was applied glass machine Vit and on one, and object lens 3 for exposure is arranged near the upper part of glass substrate l. It is irradiated with laser beam 4.5 via object lens 3 so that the resist spot condensed by resist film 2 may make d at a constant interval on resist film 2 in the radial direction of disk-like glass substrate l. If the unexposed belt inserted with two beams 4.5 is developed, it will become a land, and it will become a group if the phenomenon of the exposure belt 7.8 exposed with beam 4.5 is carried out. If only interval d is separated to the radial direction of disk l, it is irradiated with beam 4.5 on resist film 2 and glass substrate l rotates as shown in Drawing 3 (a), as shown in Drawing 3 (b), exposure belt 7.8 will be formed in both sides on both sides of unexposed belt 6 of width d. next -- if an optical system is moved for the radial direction of substrate l, i.e., arrow roppo, it arranges so that the spot of laser beam 5 may carry out distance to exposure belt 7 and may excel and overlap, and substrate l is rotated -- Drawing 4 (a) it is shown in (b) -- as Broad exposure belt 9 is formed of exposure belt 7 and exposure belt 8 Yu which polymerized in part, and new unexposed belt 6a which has width d is separated, and exposure belt 71 is formed. A broad exposure belt is formed in a resist film by repeating such a process successively. Width d of a non-exposing belt is controlled by changing the interval of laser beam 4.5, and since it is unrelated to the move pitch of an optical system, width d of an unexposed belt is maintained with high precision. The width dimension of a broad exposure belt can be extended to the sum of the spot diameter of laser beam 4.5 by the move pitch of an optical system, without controlling the output of laser beam 4.5. Drawing 5 (a) is a fragmentary sectional view showing the exposure method of the header of the master original recording for optical discs part, The arrangement explanatory view of the exposure part for bits in which Drawing 5 (b) is formed in the top view of the original recording part of Drawing 5 (a), and Drawing 6 is formed in a header part, and Drawing 7 are the time charts of the abnormal-conditions signal of a laser beam, and a deviation signal shown corresponding to Drawing 6. When abnormal-conditions signal Sl of laser beams 4 and 5 and S2 are outputted and exposure belt 7.8 is formed on resist film 2 in these figures, If abnormal-conditions signal S1.S2 turns off in time tl and deviation signal S3 of laser beam 4 is set to ON, laser beam 4 will be deflected by the position of 4a as shown in Drawing 5, and incidence to object lens 3 of laser beam 4.5 will be stopped. Next, in TI-T3, the abnormal-conditions signal of laser beam 4 is outputted during the period, resist film 2 is irradiated with laser beam 4a corresponding to it, and exposure 7a corresponding to the pit where the width of a header part is narrow is formed. At this time, the output of laser beam 4a declines a little, and a spot diameter contracts. With it, the degree of beam angle is deflected by optical deflector 16 which received deviation signal S3 so that it might be located on the extension of the center of exposure belt 9 with broad spot position 1 of a beam, and it enters into object lens 3 as beam 4a by it. And when deviation signal S3 is again turned off in time t2 and the abnormal-conditions signal of laser beams 4 and 5 is turned on, laser beam 4.5 enters into object lens 3 again, and exposure belt 7.8 is lens II! It is formed on 2. Interval d of the above-mentioned non-exposing belt can adjust laser beam 4 with sufficient accuracy by rotating deviation To serve or reflector 19 moderately by optical deflector 16. 1/2 wavelength plate 17 (Drawing 1) is for changing Polarization plane so that beams 4 and 5 may not interfere mutually. (A) EFFECT OF THE INVENTION In the present invention, width of a non-exposing belt is Holding(ed) with high precision. Therefore, a land with width and uniform height can be obtained, and a broad group can be created.

[Brief Description of the Drawings]

Drawing 1 is a schematic structure figure of a laser optics system applied to one example of this invention, Drawing 2 is a perspective view showing the exposure state of the resist film at the time of the master original recording creation for optical discs in one example of this invention, Drawings (a) (a) 3 and 4 are sectional views showing the process of one example shown in Drawing 2, Drawings 4 (b) are Drawing 3 (b) and a part plan respectively corresponding to Drawings<a> (a) 3 and 4, In Drawing 5 (a), the 5th (b) is a sectional view showing other processes of one example shown in Drawing 2, and a part plan corresponding to Drawing 5 (a), The arrangement explanatory view showing arrangement of the exposure belt formed of the process which shows Drawing 6 in 3rd [ The ] figure (a)~figure 5 (a), and Drawing 7 are time charts which show the temporal response of the abnormal-conditions signal of a laser beam, and a deviation signal corresponding to Drawing 6.