KR19990018764A - Optical discs and manufacturing method thereof - Google Patents

Abstract

Disclosed are an optical disc and a method of manufacturing the same, which can be interchangeably employed in disc players of different formats.

The disclosed optical disc comprises: a first recording surface on which an information signal reproduced by light of a first wavelength is recorded; an information substrate formed on a surface of the second recording surface on which an information signal is recorded by a light of a second wavelength; A translucent film formed on the recording surface to reflect most of the light of the first wavelength and transmitting most of the light of the second wavelength, a reflective film formed on the second recording surface and reflecting light formed on the second recording surface; It is formed to be compatible with optical disc players having different formats, including a dummy substrate bonded to a translucent film, a dummy substrate adapted to transmit incident light, a protective layer formed on a reflective film, and protecting a second recording surface. It features.

In addition, the disclosed optical disc manufacturing method comprises the steps of forming an information substrate by injecting a resin into one injection machine provided with a son substrate, and installing the information substrate in one deposition machine to deposit a translucent film and a reflective film. Forming, installing the dummy substrate in the first stocker, installing the information substrate in the second stocker disposed at a position corresponding to the first stocker, operating the first and / or second stocker, Examining the step of bonding the information substrate and the dummy substrate, characterized in that it comprises a.

Description

Optical discs and manufacturing method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc having two or more information recording layers, and more particularly, to an optical disc that can be compatible with disc players having different formats.

In general, as one way to increase the information recording capacity recorded on one optical disc, the optical disc is multilayered to include two or more information recording layers.

An example of a conventional two-layer optical disc will be described with reference to FIG. As shown, from the side to which light is irradiated, the transparent first substrate 11, the first recording layer 13 having the information recording surface, the first bonding layer 15, the spacer 17, and the second bonding layer ( 19), the second recording layer 21 and the second substrate 23. As shown in FIG.

The first substrate 11 is made of transparent PVC having a thickness of 1 mm and transmits incident light. The first recording layer 13 is made of an ultraviolet curable resin and is formed on one side of the first substrate 11. In the first recording layer 13, spiral lands 13a and grooves 13b constituting tracks are formed. A translucent film is formed on the surface 14 toward the first bonding layer 15 of the first recording layer 13 to partially transmit incident light. ZnSe (zinc selenide), BiO (bismuth oxide), CdS (cadmium sulphide), CdTe (cadmium telluride), SiC (silicon carbide) and the like are proposed as the translucent film.

In addition, the second recording layer 21 has the same configuration as the first recording layer 13, and the surface 20 facing the second bonding layer 19 is formed with a reflective layer having a reflectance of approximately 90%. It is. The first and second bonding layers 15 and 19 and the spacers 17 are for bonding the first recording layer 13 and the second recording layer 21 and maintaining the gap therebetween, and transmit incident light. . The second substrate 23 is a transparent PVC substrate to protect the second recording layer 21.

As described above, the reproduction of the information recorded on the configured optical disc is performed by using the beam 1 focused by the objective lens 3 incident on the first substrate 11 side. That is, by adjusting the focus position of the objective lens 3 so that the focused beam 1 is formed on the first recording layer 11, the information recorded in the first recording layer 11 is reproduced, and the objective lens 3 ), The beam 1 'is focused on the second recording layer 19 so that the information recorded on the second recording layer 19 can be reproduced.

As described above, the structured optical disk includes two recording layers 13 and 19, which has the advantage of increasing the capacity of information recording. However, any type of disk player, for example, digital light using a wavelength of 650 nm, can be used. It is adopted in multifunctional disk ROM (DVD-ROM).

On the other hand, in the field of the disc player technology, a digital standard multi-function disc player (DVDP), which is a new standard capable of high sound quality, high quality, and high capacity, has recently emerged. Unlike CDP, this DVDP uses a laser that emits light of 650 nm wavelength as a light source and is standardized to an objective lens with a numerical aperture of 0.6. In addition, in the standard of an optical disc (DVD) dedicated for DVDP, a normal CD has a thickness of 1.2 mm and a track pitch of 1.6 mu m, while the thickness is 0.6 mm and a track pitch of 0.74 mu m is standardized.

The above-mentioned DVDPs are developed in various forms so as to be compatible with widely used optical discs (CDs) for CDP, so that the information recorded on the CD can be reproduced not only with the CDP but also with the DVDP.

However, since DVDs have different standards from CDs, there is a problem in that recorded information cannot be reproduced using the CDP.

2, the optical disk constructed as described above is manufactured with the first substrate and the first recording layer by the first injection machine 31, and the second recording layer and the second recording layer are the second injection machine. Manufactured by (33). That is, the first injection machine 31 is formed by providing a line substrate S1 corresponding to the first recording layer and injecting the resin R1 into the inner space of the line substrate S1. On the other hand, a line substrate S2 corresponding to the second recording layer is provided in the second injection machine 33, and the second recording layer is formed by injecting the resin R2.

In this way, a translucent film is deposited on the manufactured first recording layer by the first sputtering machine 41, and a reflective layer is deposited on the second recording layer by the second sputtering machine 43. As described above, each of the two plates manufactured is installed in the first and second stockers 51 and 53, respectively, and then bonded to both surfaces of the spacers interposed between the two substrates by ultraviolet bonding.

Therefore, the conventional disk is manufactured by two injection machines 31 and 33 and two sputtering machines 41 and 43, which causes a problem in that the burden on equipment is increased.

Accordingly, an object of the present invention is to provide an optical disc having two or more recording layers and a method of manufacturing the same, which are devised in view of the above, and which can be adopted to be compatible with disc players having different formats. have.

1 is a cross-sectional view showing an optical disk having a two-layer structure according to a conventional example.

2 is a schematic view showing the manufacturing process of FIG.

3 is a cross-sectional view showing an optical disk according to an embodiment of the present invention.

4 is a schematic cross-sectional view showing the translucent film of FIG.

5a to 5f are schematic views showing the manufacturing process of FIG.

* Explanation of symbols for main parts of the drawings

61: dummy substrate 63: the first adhesive layer

65: translucent membrane 66: first recording surface

67: information board 68: the second recording surface

69: reflecting film 71: second adhesive layer

73: protective layer 110: mother substrate

120: laser device 130: developing / cleaning device

140: line substrate 150: injection machine

170: deposition machine 181, 183: first and second stocker

In order to achieve the above object, an optical disc according to the present invention has a first recording surface on which an information signal reproduced by light of a first wavelength and a second recording surface on which an information signal is recorded by light of a second wavelength are mutually different. An information substrate formed on an opposing surface, a semi-transparent film formed on the first recording surface, for reflecting most of light of a first wavelength, and transmitting most of light of a second wavelength, and formed on the second recording surface. A reflecting film for reflecting light formed on the second recording surface, a dummy substrate bonded to the semi-transparent film and configured to transmit incident light, a protective layer formed on the reflecting film, and protecting the second recording surface; It is characterized in that it can be adopted to be compatible with optical disk players having different formats.

In addition, the optical disk manufacturing method according to the present invention for achieving the above object, by injecting a resin into a single injection machine in which a line (son) substrate having a predetermined pattern is provided on each of the surfaces facing each other, the first on the surface facing each other And forming an information substrate having a second recording surface, installing the information substrate in one deposition machine, depositing a translucent film on the first recording surface, and depositing a reflective film on the second recording surface; A dummy substrate which protects the first recording surface and transmits incident light is provided on the first stocker, and an information substrate on which the translucent film and the reflective film are deposited is installed on the second stocker disposed at a position corresponding to the first stocker. And operating the first and / or second stocker, and irradiating ultraviolet light to bond the information substrate and the dummy substrate to each other. Shall be.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic cross-sectional view showing an optical disk according to an embodiment of the present invention. As shown in the figure, the optical disk is sequentially provided from the side from which the light L is irradiated, the dummy substrate 61, the first bonding layer 63, the translucent film 65, the information substrate 67, the reflective film 69, The second bonding layer 71 and the protective layer 73 are formed.

The dummy substrate 61 is a layer through which incident light L is transmitted to maintain a gap between the translucent film 65 and a turntable for a disk player (not shown). The dummy substrate 61 is made of transparent PVC or the like as a conventional optical disk.

The first bonding layer 63 is interposed between the dummy substrate 61 and the translucent film 65 and is made of a curable resin that can be cured by irradiating ultraviolet rays. The dummy substrate 61 and the translucent film 65 are bonded to each other.

The information substrate 67 is formed on the first recording surface 66 on which the information signal reproduced by the light of the first wavelength is recorded, and on the surface opposite to the first recording surface 66, and by the light of the second wavelength. It has a second recording surface 68 on which an information signal is recorded. The first wavelength refers to a wavelength of approximately 650 nm, and the first recording surface 66 corresponds to an information recording layer of a conventional digital multifunction disk. On the first recording surface 66, spiral lands 66a and pits 66b that form tracks are formed. Here, the track pitch of the first recording surface 66 is approximately 0.74 占 퐉, and the interval (between the light incident surface 61a of the dummy substrate 61 and the first recording surface 66) ) Is preferably about 0.6 mm.

The information recorded on the second recording surface 68 is reproduced by the light of the second wavelength transmitted through the translucent film 65. The second recording surface 68 corresponds to the information recording layer of a conventional compact disc (CD). Similar to the first recording surface 66, the second recording surface 68 is formed with a spiral land 68a and a pit 68b which are formed in a track. Here, the track pitch of the second recording surface 68 is approximately 1.6 占 퐉, and the distance between the light incident surface 61a of the dummy substrate 61 and the second recording surface 68 is reduced. ) Is preferably about 1.2 mm.

In the information recorded on the first recording surface 66 and the second recording surface 68, substantially the same information can be stored. For example, when the optical disc of the present invention is used as a compatible disc for audio, the same kind of audio information is recorded in different forms on each of the first and second recording surfaces 66 and 68. That is, super audio information having a sampling frequency of 96 KHz or higher and 5.1 channels of Dolby AC3 can be recorded on the first recording surface 66, and stereo sound information having a 44.1 KHz sampling frequency can be recorded on the second recording surface 68. Therefore, it operates in stereo in CDP and super audio in DVDP.

The information substrate 67 may be made of polycarbonate (PC), polymethyl methacrylate (PMMA), amorphous polyolefin (APO), photopolymer, or the like.

The translucent film 65 is deposited on the first recording surface 66, and the incident light is varied in the transmittance according to the wavelength region to reflect most of the light having a first wavelength, for example, light having a wavelength of 650 nm. Most of the second wavelengths used to reproduce the information signals recorded on the second recording layer 45, for example, light having a wavelength of 780 nm, are transmitted.

The reflective film 69 is deposited on the second recording surface 68 and reflects the light formed on the second recording surface 68. The reflective film 69 is made of aluminum, aluminum alloy, copper, copper alloy, or the like. The protective layer 73 is a layer for protecting the second recording surface 4, and is formed on the reflective film 69 by the second bonding layer 71 so that the reflective film 69 and the second recording surface ( 68) to prevent oxidation and damage.

Here, the translucent film 65 preferably has a reflectance of about 25% or more for the 650 nm wavelength and a reflectance of 18% or less for the 780 nm wavelength. This means that when playing with a CD / DVD compatible player using one light source, the CD is played using a short wavelength, for example, a wavelength of 650 nm, so that the information recorded on the second recording surface 68 of the optical disk of the present invention can be obtained. This is to prevent a situation that is difficult to reproduce from occurring.

In order to obtain the translucent film characteristics as described above, the translucent film 65 is made of a dielectric material as described later.

That is, the translucent film 65 is silicon Silicon nitride , Titanium oxide , Silicon oxide It may be composed of a dielectric material such as.

Here, the reflectance of the first wavelength and the transmittance of the second wavelength may be determined by adjusting the thickness of the translucent film 65.

In addition, the translucent film 65 is titanium oxide Layer and magnesium fluoride Layer and titanium oxide The layers may be composed of multiple dielectric materials stacked sequentially.

In addition, the translucent film 65 preferably comprises a high refractive index dielectric layer having a refractive index in the range of about 2.0 to 2.9 and a low refractive index dielectric layer having a refractive index in the range of about 1.3 to 2.0.

As described above, when the high refractive index dielectric layer and the low refractive index dielectric layer are laminated from the light incident side, the reflectance R at the interface is determined by the equation (1).

here, and Each is the refractive index of the high refractive index dielectric layer and the low refractive index dielectric layer, d is the thickness of the high refractive index dielectric layer, and λ is the wavelength of incident light.

Therefore, as shown in FIG. 4, the translucent film 65 is formed of a high refractive index dielectric layer 65a, a low refractive index dielectric layer 65b, and a high refractive index dielectric layer (sequentially stacked from the first recording surface 66 side). 65c). As shown, each dielectric layer comprises silicon nitride In the case where the high refractive index layers 65a and 65c have a refractive index of 2.88 and the low refractive index layer 65b has a refractive index of 1.95, the thickness of the second layer is 740 kPa and the thickness of the third layer is 625 kPa. Table 1 shows the transmittance / reflectance characteristics of the light having a first wavelength of 633 nm and the light having a second wavelength of 780 nm when the thickness of the first layer was changed to 1300 Hz, 1600 Hz, and 1900 Hz.

Wavelength layer structure 633 nm 780 nm Remarks Reflectance (DVDP Reflectance) Transmittance (CDP Reflectance) 1300/740/625 29% 55% Works with CDP 1600/740/625 36% (34%) 60% (45%) Works with CDP / DVDP 1900/740/625 32% 45% Works with DVDP

As shown, the reflectance for 633 nm is low at 29% and the transmittance for 780 nm is high at 55% when the thickness of the first layer 65a is around 1300 Hz, so that it does not work with DVDP and works with CDP. Can be. On the other hand, when the thickness of the first layer 65a is around 1600 Hz, the reflectance for 633 nm is 36% (the reflectance for DVDP is 34%) and the transmittance for 780 nm is 60%, which works in both DVDP and CDP. It can be seen. Therefore, by adjusting the thickness of the dielectric layer or by adjusting the refractive index, it is possible to selectively adjust the reflectance of light with respect to the first and second wavelengths.

Hereinafter, a method of manufacturing an optical disk configured as described above with reference to FIGS. 5A to 5F will be described in detail.

Referring to FIG. 5A, a mother substrate 110 is rotatably installed, and the mother substrate 110 is exposed to light by irradiating a laser beam to the mother substrate 110 using the laser device 120. . Thereafter, as illustrated in FIG. 5B, the mother substrate is developed and cleaned using the developing / cleaning apparatus 130 to form a predetermined pattern on the mother substrate 110.

As shown in FIG. 5C, a son substrate 140 having a pattern corresponding to the pattern of the mother substrate 110 is manufactured by electroplating or the like on the mother substrate 110.

Here, each of the mother substrate 110 and the line substrate 140 is provided separately with respect to the first and second recording surfaces 66 and 68 of the information substrate (67 in FIG. 3).

Referring to FIG. 5D, the pair of line substrates 141 and 143 provided as described above are spaced apart by an interval corresponding to the thickness of the information substrate 67. Install under. Then, by injecting and curing resin between the line substrates 141 and 143, the information substrate 67 having the first and second recording surfaces 66 and 68 on the surfaces facing each other is formed. Here, the resin, that is, the material of the information substrate may be composed of polycarbonate (PC), polymethyl methacrylate (PMMA), amorphous polyolefin (APO), photopolymer (photo polymer) and the like.

Thereafter, the information substrate 67 is installed in one deposition machine, for example, a sputtering machine 170, a translucent film is deposited on the first recording surface 66, and a reflective film is deposited on the second recording surface 68. do. In this case, the deposition machine has a structure capable of depositing materials of different materials on each of both surfaces of the information substrate 67. That is, when the sputtering machine 170 is employed as the deposition machine, two targets 173 and 175 are installed in the chamber 171 facing each of the first and second recording surfaces 66 and 68. A semi-transparent film 65 and a reflective film on each of the first and second recording surfaces 66 and 68 of the information substrate 67 at the same time, having two electron guns 174 and 176 for generating accelerated electrons. 69) can be deposited.

Since the materials of the translucent film and the reflective film are as described above, detailed description thereof will be omitted.

Thereafter, as shown in FIG. 5F, the dummy substrate 61 is prepared to protect the first recording surface 66 and transmit incident light, and to bond the prepared dummy substrate 61 to the information substrate. The dummy substrate 61 is installed on the first stocker 181. The information substrate 67 is installed on the second stocker 183 disposed to correspond to the first stocker 181.

After applying the adhesive material that can be cured by ultraviolet rays between the information substrate 67 and the dummy substrate 61, the first and / or second stockers 181 and 183 are operated to emit ultraviolet rays. Irradiation joins the information substrate 67 and the dummy substrate 61 to complete an optical disc. Therefore, the first adhesive layer 63 is formed between the translucent film 65 and the dummy substrate 61. Here, in applying the adhesive, a conventional spin coating method is used to uniformly apply the coating.

In addition, it is preferable to further include forming a protective layer 73 protecting the second recording surface 68 and the reflective film 69 on the reflective film 69. In this case, a second adhesive layer 71 is formed between the reflective film 69 and the protective layer 73.

Therefore, the optical disc according to the present invention has a different format by forming the first and second recording surfaces on each of both sides of the information substrate to record information, and by forming a translucent film selectively varying the transmittance according to the wavelength on the first recording surface. Different types of disc players, for example, CDP and DVDP can be adopted. In addition, since the optical disk can be manufactured by an injection machine and a deposition machine, the mechanical properties of the information substrate can be improved, and the process can be simplified and the cost can be reduced.

Claims (11)

The first recording surface on which the information signal reproduced by the light of the first wavelength is recorded, the information substrate formed on the surface of the second recording surface on which the information signal is recorded by the light of the second wavelength is opposed to each other, and on the first recording surface. A semi-transparent film formed to reflect most of the light of the first wavelength and most of the light of the second wavelength, a reflective film formed on the second recording surface and reflecting light formed on the second recording surface; A dummy substrate bonded to the translucent film and adapted to transmit incident light, and a protective layer formed on the reflective film to protect the second recording surface, can be adopted to be compatible with optical disc players having different formats. An optical disc characterized in that the. The method of claim 1, wherein the information substrate is made of polycarbonate (PC), polymethyl methacrylate (PMMA), amorphous polyolefin (APO), characterized in that it comprises any one selected from the group consisting of photopolymers. Optical disc. The method of claim 1, wherein the translucent film is silicon, silicon nitride, titanium oxide, silicon oxide, An optical disc comprising any one selected from the group consisting of. The optical disc of claim 1, wherein the reflective film comprises any one selected from the group consisting of aluminum, aluminum alloy, copper, copper alloy, and silver. The optical disc according to any one of claims 1 to 4, wherein each of the dummy substrate and the information substrate has a thickness of approximately 0.6 mm and is bonded by spin coating. Injecting a resin into a single injection machine provided with a line substrate having a predetermined pattern on each of the surfaces facing each other to form an information substrate having first and second recording surfaces on the surfaces facing each other; Installing the information substrate in a machine, depositing a translucent film on the first recording surface, and depositing a reflective film on the second recording surface, and protecting the first recording surface and transmitting the incident light to the first substrate. Installing the information substrate on which the translucent film and the reflective film are deposited, respectively, on a second stocker disposed at a position corresponding to the first stocker, and operating the first and / or second stockers, And irradiating ultraviolet light to bond the information substrate and the dummy substrate to each other. 7. The manufacturing method of an optical disc according to claim 6, further comprising a step of forming a protective layer on the reflective film to protect the second recording surface and the reflective film. The method of claim 6 or 7, wherein the material of the information substrate comprises any one selected from the group consisting of polycarbonate (PC), polymethyl methacrylate (PMMA), amorphous polyolefin (APO), photopolymer Optical disk manufacturing method characterized in that. The method of claim 6 or 7, wherein the translucent film is silicon, silicon nitride, titanium oxide, silicon oxide, Optical disk manufacturing method comprising any one selected from the group consisting of. The method of claim 6 or 7, wherein the reflective film comprises any one selected from the group consisting of aluminum, aluminum alloy, copper, copper alloy, and silver. The method of claim 6 or 7, wherein each of the dummy substrate and the information substrate has a thickness of approximately 0.6 mm and is bonded by spin coating.