MXPA96005564A - Optical disc structure, method of manufacturing it and its manufacturing device - Google Patents

Abstract

The indication members that are provided around a central hole in a disc do not detrimentally affect the reference surfaces to be fixed, and a clear stable indication is maintained. For this purpose, the first and second optical discs (11, 12) having light transmissive annular disc substrates (11a, 12a) with a common central hole (10), one of the surfaces of each of which transmissive disc substrates of light is provided with a reflection film (11b, 12b), they are fixed to each other as a body with an interposed adhesive layer (13), in such a way that the reflection films are opposite one another, forming from this way a composite disc (100). Label members (11d, 12d) are provided from the side of the reflection film by printing or adhering in the flat portions surrounding the central hole (1).

Description

"OPTICAL DISC STRUCTURE, METHOD OF MANUFACTURING OF THE SAME AND APPARATUS FOR MANUFACTURE OF THE SAME" TECHNICAL FIELD The present invention relates generally to a recording medium for use in recording / reproducing audio information, video information or normal data and more particularly to an optical disc structure capable of recording / reproducing signals by means of light, a method of fabrication of the optical disc structure and an apparatus for manufacturing the optical disc structure.

ANTECEDENTS OF THE TECHNIQUE An optical disk constructed in such a way that the recorded signals are reproduced by means of a laser beam. In an example of this type of optical disk, signal recording areas are provided on both sides of the disk. Recently, a small video disk (with a diameter of approximately 12 centimeters) has been developed for high density recording. In the small-sized high-density video disc, the majority of a flat portion of the disc extending from a central hole to the beginning region of registration is used as a fixation area (to be held and retained by a mecnis or disk retention). In this way, the flat portion functions as a reference surface of the disk in relation to the optical system when the disk is mounted on a turntable and fixed by a fixing device. If a conventional label is adhered to this disc as a means of indication, the following problems will occur (a) and (b): a) Because a very small tilt tolerance angle (tilt) of the disc is required, even when the disc is slightly inclined, the quality of a reproduced signal is greatly degraded. If the aforesaid indicating means is used, the disc tends to be easily tilted due to a sheet adhered to the fixing area or unevenness of the printed ink, etc. b) The sheet adheres or the ink, etc. is printed on a limited area of the disc's fixing area. When the disk is mounted on a turntable and is retained by the fastening apparatus, the fastening apparatus can cause damage to the indication surface because a particular slip occurs at the time of starting the operation. As a result, the indication may not be clear, the reference surface of the fixing area may be tilted or the indication means may be removed. An object of the invention is to provide an optical disk structure wherein the indication means provided on the flat surfaces surrounding the central hole in a disk can maintain a clear, stable indication state, a method of manufacturing the disk structure optical and an apparatus for manufacturing the same. An optical disk structure in which the stable clear indication state can be maintained and even when the indicating means is provided, the reference surfaces to be fixed are not adversely affected, a method of manufacturing the optical disk structure and a apparatus to manufacture it.

EXHIBITION OF THE INVENTION In order to achieve the objects, an optical disk structure is provided wherein the first and second optical discs having light transmissive annular disc substrates with a common central hole, one of the surfaces of at least one of the substrates of Transmissive light disc is provided with a reflection film, they are fixed to each other as a body with an adhesive layer interposed in such a way that the reflection film is opposite to the adhesive layer, thereby forming a composite optical disc comprising the optical disk structure: an internal surface of a portion of at least one of the light transmissive substrates, the portion being oriented towards a fixing device and being positioned around the central hole; an indication means that is provided to the internal surface by means of a printing and adhesion; and the adhesive layer with the protective properties of light that is provided between the indicating means and the other of the light transmissive disc substrates. In accordance with this means, the printed or adhered indicating means is placed inside the disc. Therefore, the indication means is not removed or damaged by friction, etc. between the disc and a fixing device or a rotary table, and a clear indication is maintained. In particular, since the adhesive layer which is provided in the region of the indicating means has light-protecting properties, the indicated material is not made less visible due to the light from the reverse side. In accordance with this invention, an optical disk structure is also provided wherein the first and second optical discs having annular light transmissive disc substrates with a common center hole, one of the surfaces of at least one of the substrates of Transmissive disc of light is provided with a reflection film, they are fixed one on the other as a body with an adhesive layer interposed in such a way that the reflection film is opposite the adhesive layer, thus forming a composite optical disc, the optical disc structure comprising: a recess portion recessed in a thickness direction in a portion of at least one of the light transmissive disc substrates around the central bore; and an indication means which is provided on a lower surface of the recess portion by means of printing and adhesion. According to this means, a printed or adhered indicating means is provided from the side of the reflection film between the attached discs. In this way even when the flat portions surrounding the central hole are used as the fixing areas that function as reference surfaces, no influence of the indicating means will occur. The indication means is not removed or damaged by friction, etc. between the disc and a fixing device or a rotary table and a clear indication is maintained. In particular, the indication means is printed or adhered to the lower part of the recess portion. Therefore, even when there is a variety in thickness in the printed matter or the sheet, the variation does not deform the fixing areas.

BRIEF DESCRIPTION OF THE DRAWINGS Figure IA is a plan view of an optical disk composed in accordance with one embodiment of the present invention; Figure IB is a cross-sectional view of the composite optical disc shown in Figure IA; Figure 1C is a partially amplified view of the composite optical disc shown in Figure IB; Figure ID shows a relationship between the composite optical disc and a fixation device; Figure 2 is a cross-sectional view showing a main part of an optical disk composed in accordance with another embodiment of the invention; Figure 3 is a cross-sectional view showing a main part of an optical disk composed in accordance with yet another embodiment of the invention; Figure 4 is a cross-sectional view showing a main part of an optical disk composed in accordance with yet another embodiment of the invention; Figure 5 is a cross-sectional view showing a main part of an optical disk composed in accordance with yet another embodiment of the invention; Figure 6 is a cross-sectional view showing a main part of an optical disk composed in accordance with yet another embodiment of the invention; Figure 7 is a cross-sectional view showing a main part of an optical disk according to still another embodiment of the invention; Figure 8A is a plan view of an optical disk composed in accordance with the other embodiment of the invention; Figure 8B is a cross-sectional view of the composite optical disc shown in Figure 8A; Figure 8C is a partially amplified view of the composite optical disc shown in Figure 8B; Figure 9 is a cross-sectional view showing a main part of an optical disk composed in accordance with another embodiment of the invention; Figure 10 is a cross-sectional view showing a main part of an optical disk composed in accordance with yet another embodiment of the invention; Figure HA is a plan view of an optical disk composed in accordance with another embodiment of the invention; Figure 11B is a cross-sectional view of the composite optical disc shown in Figure HA; Figure 12A is a plan view of an optical disk composed in accordance with another embodiment of the invention; Figure 12B is a cross-sectional view of the composite optical disc shown in Figure 12A; Figure 13A illustrates the steps of a method of manufacturing a composite optical disk, in accordance with one embodiment of the invention; Figure 13B illustrates the steps of a method of manufacturing an optical disk composed in accordance with another embodiment of the invention; Figure 14A shows an apparatus for manufacturing an optical disk composed in accordance with an embodiment of the invention; Figure 14B shows an apparatus for manufacturing an optical disk composed in accordance with another embodiment of the invention; Figure 15 illustrates the advantages of the composite optical discs of the present invention; Figure 16 is a graph showing the measured tilt or tilt values to explain the advantages of the invention; and Figure 17 is a graph 'showing the measured tilt or tilt values to explain the advantages of the invention.

BEST WAY TO CARRY OUT THE INVENTION The embodiments of the present invention will now be described with reference to the accompanying drawings. Figures IA to ID show one embodiment of the present invention. Figure la is a plan view, Figure IB is a cross-sectional view and Figure 1C is a partially enlarged view. The first and second optical discs 11 and 12 have a common central hole 10 of the same diameter. The first and second optical discs 11 and 12 include the disc substrates of the annular disc 12a and 12a of light, respectively. A surface of the disk substrate 11 and a surface of the disk substrate 12a have reflection films 11b and 12b. The protective films 11c and 12c are provided on the upper surfaces of the reflection films 11b and 12b. The first and second optical discs 11 and 12 are fixed to each other as a body with an interposed adhesive layer 13, such that their reflection films 11b and 12b are opposite each other. In this way, the first and second optical discs 11 and 12 constitute a composite optical disc 100. Figure IA shows the external appearance of the composite optical disk 100. The disk 100 includes, from the outer peripheral side to the inner peripheral side, a non-signal region 101, a signal registration region 102, a fixing region 103, a bank portion 104 and a central hole 10. In the case of this composite optical disk 100, the fixing region 103 also functions as an indication section. The indication section is constituted in such a way that indication lid and 12d members are provided within the regions of the light transmissive disc substrates lia and 12a corresponding to the fixation region 103. The lid and 12d indication members show characters, figures, signs, etc. which can be recognized from the outer surfaces of the composite optical disk 100. The materials and dimensions of the respective elements of the composite optical disk 100 will now be described. The light transmissive disc substrates lia and 12a are formed eg of polycarbonate, acrylic resin or glass material. The adhesive layer 13 is formed from a hot melt (e.g., PPET2009 manufactured by TOA GOSEI KAGAKU KOGYO) with a thickness of about 10 to 30 microns. The optical reflection films 11b and 12b are formed of aluminum, etc. with a thickness of approximately 0.1 micrometer. The protective films 11c and 12c are formed e.g., of a curing coating material with ultraviolet light (e.g., SK500 manufactured by SONY CHEMICAL) with a thickness of about 5 to 15 micrometers. Preferably, the adhesive layer 13 should have impervious properties. The lid and 12d indication members are formed by adhering the labels printed on the sheets or affecting direct printing on the disc substrates. Alternatively, the lid and display members 12d may be formed by coating or cutting. The adhesive that is provided between the lid members and 12d of indication has light-protective properties. If the adhesive passes light, the characters or figures on the indication members may become less visible. In accordance with the previously described disc, the indication means formed by printing or adhering the sheets is placed inside the disc. Therefore, the indication means is not removed or damaged by friction, etc. between the disc and a fixing device or a rotary table, and a clear indication is maintained. In particular, since the adhesive layer which is provided in the region of the indication means has light-protective properties, the indicated material is not made less visible due to the light from the reverse side. Therefore, the characters or figures indicated by the indication members can be clearly seen. Figure ID shows the state in which the composite optical disk 100 is mounted on a turntable 121 and the fixing region of the disk is retained by a fixing device 120. The following consideration should be given by providing the lid members and 12d of indication, when the lid members and 12d of indication are printed, if an offset printing is adopted, the thickness of each indication member can be limited to approximately 15 micrometers even in the case of a multi-color printing. However, if silk stencil printing is generally adopted and the number of colors is increased, the thickness becomes 40 to 50 micrometers or more. To solve the aforementioned problem, lie portions 12e and recess 12e may be formed in the light transmitting disc substrates lia and 12a from the reverse side as the forming portions of the indication member, and the lid and 12d indication imebs may be left behind. embedded in the lie and recess portions 12e, as shown in Figures 2 and 3. In this way, printing with greater thickness can be easily carried out and a high indication effect can be exhibited. In many cases, a boundary portion is provided between a die cutter (to form pinholes during manufacture) and a die cutter is provided at a position between a set area and an initial portion of a signal registration region. At the same time, the annular projections llf and 12f are provided in the limit portion. The annular lf and 12f projections are formed to protect the signal surfaces when the manufactured discs are stacked. When the disc with the annular lf and 12f projections is formed, the disc substrates lia and 12a are formed using a mold having a projection on the side corresponding to the internal surface of each substrate. Therefore, the lie portions 12e and recess 12e can be formed simultaneously in an easy manner with the formation of the annular projections llf and 12f, without requiring special manufacturing steps. In the aforementioned embodiments, the first and second discs 11 and 12 have protection films 11c and 12c. In the case of the optical disc 100 composed of this invention, the first and second discs 11 and 12 are formed as a body with the interposed adhesive layer 13, in such a way that their reflection films 11b and 12b are opposite one another. Therefore, as shown in Figures 4 and 5, the protection films 11c and 12c can be omitted. In this way, the manufacturing steps of the protection films 11c and 12c can be omitted. In the embodiments of Figures 4 and 5, protection films are omitted in the embodiments of Figures 2 and 3. In each embodiment, the common parts are indicated by like reference numbers and a description thereof is omitted. In accordance with the optical disc of this invention, a labeling means is provided by printing or adhering sheets on the side of the reflection film between the mutually fixed discs. Accordingly, even when the outer surfaces of the optical disc are used as fixing areas that serve as reference surfaces, there is no influence due to the labeling means. The labeling medium is not removed or damaged by friction etc. between the disc and the fixing device or the rotating table. A clear indication can be maintained.

The indicated material of the indication section includes an identification signal of "side A" and "side" B ", the title of the registered information (eg, the title characters, figures), the name of a manufacturer, the manufacturing number, etc. In Figures 2 to 5, the edges of the portions lie and However, as shown in Figures 6 and 7, the edges of the lie and recess portions 12e may be curved.The present invention is not limited to the aforementioned embodiments. is a plan view, Figure 8B is a cross-sectional view and Figure 8C is a partially amplified view The first and second optical discs 11 and 12 have a common central hole 10 of the same diameter The first and second disks 11 and 12 optics include light transmissive annular disk substrates 12a and 12a, respectively, one surface of the disk substrate 11 and one surface of the disk substrate 12a have reflective films 11b and 12b.The protective films 11c and 12c are p They are provided on the upper surfaces of the reflection films 11b and 12b. The first and second optical discs 11 and 12 are fixed to each other like a body, with an interposed adhesive layer 13, in such a way that their reflection films 11b and 12b are opposite one another. In this way, the first and second optical discs 11 and 12 constitute a composite optical disc 100. Figure 8A shows the external appearance of the composite optical disk 100. The disk 100 includes, from the outer peripheral side to the inner peripheral side, a non-signal region 101, a signal registration region 102, a fixing region 103, a bank portion 104 and a central hole 10. In the case of this composite optical disk 100, the fixing region 103 also functions as an indication section. The indication section is constituted in such a way that the lid and display members 12d are provided within the regions of the light transmissive disc substrates lia and 12a corresponding to the fixation region 103. The lid and 12d indication members show characters, figures, signs, etc. which can be recognized from the outer surfaces of the composite optical disk 100. In this disc, the annularly projecting portions 11x and 12x of the lens are formed in the portions of the outer surfaces of the fixation region 103, so that the matter indicated in the lid and display members 12d can be amplified.

The materials and dimensions of the respective elements of the composite optical disk 100 are the same as those in the above embodiments. The following consideration should be given in providing the lid and 12d indication members. When the lid members 12d and the indication members are printed, if an offset printing is adopted the thickness of each indication member can be limited to approximately 15 micrometers even in the case of multiple color printing. However, if silk stencil printing is generally adopted and the number of colors is increased, the thickness becomes one of 40 micrometers to 50 micrometers or more. To solve the aforementioned problem, the lie portions 12e and recess 12a may be formed in the light transmissive disc substrates lia and 12a from the reverse side as forming portions of the indication member, and the lid and display 12d members may be embedded in the lie and work portions 12e as shown in Figures 9 and 10. In this way, printing with greater thickness can be carried out more easily and a higher indication effect can be exhibited. In many cases, a boundary portion between a die cutter (to form pinholes during manufacture) and a die holder is provided at a position between a set area and a start portion of a signal registration region. At the same time, the ring projections are provided in the limit portion. The annular projections are formed to protect the surfaces of the signal when the manufactured discs are stacked. When the disc with the annular projections is formed, the disc substrates Ia and 12a are formed using a mold having a projection on the side corresponding to the internal surface of each substrate. Therefore, the recess portions lie and 12e can easily be formed simultaneously with the formation of the annular projections, without having to provide special manufacturing steps. In addition, if the annular projections are formed to also serve as the lens portions 11x and 12x, there is no need to add steps to form the lens portions 11x and 12x. The present invention is not limited to the aforementioned embodiments and various modifications can be made. In the aforementioned modalities (FIGURES 8C and 9), the first and second discs 11 and 12 have protection films 11c and 12c. In the case of the optical disc 100 composed of this invention, the first and second discs 11 and 12 are formed as a body with the interposed adhesive layer 13, in such a way that their reflection films 11b and 13b are opposite one another. Therefore, as shown in FIGURE 10, protection films 11c and 12c can be omitted. In this way, the manufacturing steps of the protection films 11c and 12c can be omitted. In the aforementioned embodiments, the external surface portions of the indication means are used as a fixing region, the lens portions 11x and 12x are formed on the outer peripheral side of the indication means. However, it goes without saying that portions llx and 12x of the lens can be formed on the inner peripheral side, for example, as indicated by the dashed lines. The positions and number of portions of the lens can be chosen freely according to the indication means. It is possible, therefore, that a plurality of lens portions are formed on the side of the external surface of the indicating means and on the inner and outer peripheral sides of the indication means, and in the regions between the lens portions are They use as the fixing regions to hold the disk. If these fixing regions are used, the fixing device is automatically located between the lens portions, and the disk can advantageously be placed in a reproduction apparatus. In each mode, the common parts are indicated by the same reference numbers and a description of them is omitted. In accordance with the optical disc of this invention, a labeling means is provided by printing or adhering the sheets on the side of the reflection film between the mutually fixed discs. Accordingly, even when the outer surfaces of the optical disc are used as the fixing areas that serve as reference surfaces, there is no influence due to the labeling means. The labeling medium is not removed or damaged by friction, etc. between the disc and the fixing device or the rotating table. A clear indication can be maintained. In particular in accordance with the disc of this invention, the indicated material can easily be seen from the outside due to portions 11x and 12x of the lens. FIGURES HA and 11B show still another embodiment of the optical disc of the invention. FIGURE HA is a plan view and FIGURE 11B is a cross-sectional view. In this embodiment, an additional labeling means is provided on the outer peripheral side. In the above embodiments, the lid and 12d indication members are provided on the internal peripheral side. However, the indication members 11g and 12g may be provided on the outer peripheral side, likewise. FIGURES 12A and 12B show still another embodiment of the optical disc of the invention. FIGURE 12A is a plan view and FIGURE 12B is a cross-sectional view. In the case of the disk of this mode, the information can be read from one side only. Registration signals are recorded on the second disk 12 alone, and the first disk 11 comprises a transparent substrate alone. In this case, a large indication member llh may be provided on the inner surface of the first disk 11. A method for manufacturing the optical discs described above will now be described. FIGURE 13A illustrates the steps of manufacturing a method in accordance with one embodiment of the invention, and FIGURE 13B illustrates the steps of manufacturing a method according to another embodiment of the invention. An optical disk composed in accordance with this invention comprises first and second optical discs. Each optical disc has an annular light transmissive disc substrate, or a central hole. A reflection film is provided on one side of the disk substrate. The first and second optical discs are fixed to each other as a body with an adhesive layer interposed in such a way that their reflection films are opposite one from the other. The indication means is printed or adhered from the side of the reflection film in the region surrounding the central hole. The adhesion step is carried out after a step providing the indication means, eg, one step of label printing. Specifically, in FIGURE 13A, a mold (generally called "die cutter") that is provided in advance with pits representing the registration information, is adhered to a resin molding machine such as an injection molding machine. Then, a disc of a transparent plastic material such as polycarbonate or acrylic resin is obtained (step Sil), where the punctures of the die cutter are accurately transferred. A metal, for example aluminum, is deposited by vacuum deposition or sputtering on that disk surface, which is provided with the pits, thereby forming a reflection film (step S12). Subsequently, a curing resin is coated with ultraviolet light, etc. by means of a rotating device etc. on the surface of the reflection surface, thereby forming a protective film to protect the reflection surface from damage or oxidation (step S13). In this way, the first and second disks are formed and the labels are printed in the predetermined areas (within the fixing regions) (step S14). After printing, the discs adhere to each other (step S15). In the adhesion step, a thermoplastic adhesive called "hot melt" is coated by a roller coating apparatus, etc. on the adhesion surfaces of the discs. The adhesion surfaces with the adhesives are made to bump against each other and are pressed into each other under pressure, thus forming a single composite optical disc. In the embodiment shown in FIGURE 13B, the step of forming the protection film is omitted. In a method and apparatus for manufacturing the optical disc of the present invention, the following techniques are applicable in particular for the adhesion step of the two discs. As shown in FIGURE 14A, an adhesion (pressure) apparatus comprises plate-like upper and lower pressing plates 210 and 220 having diameters essentially equal to or greater than those of the discs. The disc-like elastic members 211 and 221 for pressing the outer surfaces of the first and second discs are provided on the inner surfaces of the pressure plates 210 and 220. The first and second discs 11 and 12 interspersed with the adhesive layer 13 are transferred to the space between the elastic members 211 and 221. The lower pressure plate 220 is fixed to a support table (not shown), and the upper pressure plate 210 is fixed to a vertical movement mechanism. The vertical movement mechanism gradually drops to fix the disk structure. The portions 21a and 22a of the elastic members 211 and 221, corresponding to the lid members and 12d for indicating the discs, are formed of a material different from the material of the other portions 21b and 22b. Specifically, the portions corresponding to the indication members are formed of a relatively soft material, such as rubber and silicone (e.g., hardness: JISA40), and the other portions, excluding the indication members, are formed of a relatively hard material such as EP rubber (e.g., hardness: JISA65). In this embodiment, the appropriate pressure in the adhesion step was 2 to 3 kilograms per square centimeter and the appropriate pressure time was 3 seconds, in the case of undiscus of 120 millimeters. The pressure apparatus is not limited to the foregoing and certain advantages are obtainable with the apparatus shown in FIGURE 14B. In this embodiment, the annular recess portions 21d and 22d (approximately 0.1 millimeter deep) are formed in those disc side portions of the pressure plates 210 and 220, which correspond to the indication members. The elastic sheets (eg, CIEGAL 7355-OFF of 1.35 millimeters: manufactured or DAIICHI REISU) are interposed between the discs, on the one hand, and the plates 210 and 220 of pressure, on the other. In this state, the disc structure is pressed as in the previous modalities. The same advantages as in the previous embodiments with this method and apparatus are obtainable. The force of pressure on the indication members becomes smaller than that in the other portions due to the following reason. Printing is effected on the indication members by means of a stencil printing method, or a punching method. Then, the ink dries. For example, if a curing ink with ultraviolet light is used, the ink is cured by ultraviolet light after printing. An adhesive such as a hot melt material is coated by means of a roll coating apparatus, etc. on both discs. Those surfaces of the discs that are coated with the adhesives, are made to bump against each other and are pressed against each other. The thickness of the indication member increases by the degree corresponding to the thickness of the ink layer, resulting in an inequality due to the characters, etc., printed in ink. If the discs are pressed by elastic members with uniformly high hardness, the unevenness appears on the external surfaces of the disc indication members. As described above, in the case of small disks, the regions of the indication members serve as attachment regions. The fixation regions are used as reference surfaces and need to be largely flat. In the present invention, the structure of the elastic members or the structure of the pressure es are designed so that the inequality does not appear on the external surfaces of the indication members. FIGURE 15 is a table showing the comparison results of the inclinations or tipping between the case (printing of internal surface) where a label is printed (thickness: 50 micrometers); area: 3 square millimeters) in about half of its entire circumference of the fixing area, such as in the present invention, and the conventional case (external surface printing). FIGURES 16 and 17 are graphs where the variations in inclination or tipping of 22 millimeters radius to 58 millimeters radius of a spiral device are plotted (a measuring device moves radially while the disc is being rotated) . FIGURE 16 shows the case of an internal surface printing disc and FIGURE 17 shows the case of an external surface printing. In FIGURE 15, "r" indicates the radial position on the disk, and "scale" is a scale of variation of tilt in a disk rotation, as measured at 30 millimeters in radius and 50 millimeters in radius. As can be seen from the table and the graphs, the scale of variation is much smaller in the case of the internal surface printing that is adopted in the present invention. The disc inclination occurs hardly and the signal reproduction is excellent can be carried out in the case of using a high density recording disk. As described above, in accordance with the present invention, the indication means buried within the disk in the portion surrounding the central hole, can maintain a stable, clear indication state. In addition, the indication means does not detrimentally affect the reference surfaces for fixation. Industrial Applicability This invention is used effectively in the field of using and manufacturing a recording / reproducing apparatus for an optical disc and the manufacture and sale of an optical disc.

Claims (20)

1. CLAIMS: 1. An optical disc structure wherein the first and second optical discs having annular light transmissive disc substrates (11, 12) with a common central hole (10), one of the surfaces of at least one of whose disc substrates Transmissive light is provided with a reflection film (11b, 12b), fixed one on the other as a body with an interposed adhesive layer (13), such that the reflection film is opposite to the adhesive layer, forming in this way a composite optical disc (100) the structure to the optical disc comprises: an internal surface of a portion (103) of at least one of the light transmissive disc substrates (Ha, 12a), the portion remaining oriented toward a fixing device and being positioned around the central hole (110); an indication means (11b) that is provided on the inner surface by means of printing and adhesion; the adhesive layer (13) with the light-protecting properties is provided between the indicating means (11b) and the other of the light transmissive disc substrates. 2. An optical disk structure wherein the first and second optical discs having annular light transmissive disc substrates (11, 12) with a common central hole (10), at least one of the surfaces of which transmissive disc substrates it is provided with a reflection film (11b, 12b), they are fixed to each other as a body with an interposed adhesive layer (s), in such a way that the reflection film is opposite to the adhesive layer, thereby forming a composite optical disc (100), the optical disc structure comprises: a recess portion (He, 12e) recessed in a thickness direction in a portion of at least one of the light transmissive disc substrates (Ha, 12a) around the central hole (10), and an indication means (lid, 12d) that is provided on a lower surface of the recess portion (He, 12e) by means of printing and adhesion. The optical disc structure according to claim 2, wherein the protective films (He, 12c) are formed on the upper surfaces of the reflection films (11b, 12b) of the first and second optical discs (11, 12) and the adhesive layer (13) is interposed between the protective films. 4. The optical disc structure according to claim 2, wherein the adhesive layer (13) is located directly on the reflection films of the first and second optical discs (11, 12). The optical disc structure according to claim 2, wherein the annular projections (llf, 12f) are formed on the outer peripheries of the indication means and on the external surfaces of the light transmissive disc substrates, and the Recess portions are formed on the inner surfaces of the light transmissive disc substrates so that they correspond to the above-mentioned projections. The optical disc structure according to claim 2, wherein the external surface of the portion where the indicating means (He, 12e) is provided is a fixing region (103) for retaining the disc. The optical disc structure according to claim 2, wherein the indicating means (He, 12e) is formed in such a way that one of at least one character and at least one sign representing at least one The title of the registered information is visible from the outside of the disk structure. 8. An optical disc structure wherein the first and second optical discs (11, 12) having annular light transmissive disc substrates (Ha, 12a) with a common central hole (10), one of the surfaces of less one of whose light transmissive disc substrates is provided with a reflection film (11b, 12b) are fixed to one another as a body with an interposed adhesive layer (13), such that the reflection film is opposite to the adhesive layer thereby forming a composite optical disc, wherein the indication means (lid, 12d) is provided by printing and adhesion from the side of the reflection film ( 11b, 12b) of at least one of the first and second optical discs within the disc in a portion surrounding the central hole (10), and a projection lens portion (11x, 12x) is formed in a portion of a surface external of the portion surrounding the central hole (10), and corresponding to the indicating means (lid, 12d) and an essentially flat fixing region (103) is provided adjacent to the lens portion (11x, 12x). The optical disc structure according to claim 8, wherein the lens portion (11x, 12x) is formed in an annular configuration on the outer surface and is positioned on the inner peripheral side of the indication means (lid, 12d). 10. The optical disc structure according to claim 8, wherein the lens portion (11x, 12x) is formed in an annular configuration on the external surface and is located on the outer peripheral side of the indication means (lid, 12d) . 11. The optical disc structure according to claim 8, wherein the region adjacent to the lens portion (11x, 12x) is a fixation region for retaining the disc. The optical disc structure according to claim 8, wherein a plurality of lens portions (11x, 12x) are provided on the external surface and on the peripheral internal and external sides of the indication means, and a region between the lens portions on the inner and outer peripheral sides is a fixing region. 13. A method of manufacturing an optical disc comprising: a step (Sil) to form the light transmissive disc substrates (Ha, 12a) having a common central hole (10) and registration regions in radially intermediate regions, bites representing the registration information that is transferred to the registration regions by means of a punching machine; a step (S12) for providing reflection films (11b, 12b) on the surfaces of the light transmissive disc substrates (Ha, 12a) provided with pitting; a step (S14) for providing an indication member (He, 12e) by printing and adhering on at least one of those sides of the light transmissive disc substrates (Ha, 12a) that are provided with the reflection films ( 11b, 12b) and in a portion oriented towards a fixing region around the central hole (10); and a step (S15) for fixing the first and second optical discs (11, 12) with the indication member (He, 12e) in one another as a body by means of an adhesive (13) in such a way that the reflection films (11b, 12b) are opposite one from the other. 14. A method of manufacturing an optical disk comprising: a step (Sil) to form light transmissive disc substrates (Ha, 12a) having a common central hole and recording regions in the radially intermediate regions with pitting representing that the registration information is transferred to the registration regions by means of a punching machine; a step (S12) for providing reflection films (11b, 12b) on the surfaces of the light transmissive disc substrates (Ha, 12a) that are provided with the pitting; a step (S13) for providing protection films (11c, 12c) on the upper surfaces of the reflection films (11b, 12b); a step (S14) for providing an indication member (He, 12e) by printing and adhering on at least one of those sides of the light transmissive disc substrates (Ha, 12a) that are provided with the protective films ( He, 12c) and in a portion oriented towards a fixing region around the central hole (10); and a step (S15) for fixing the first and second optical discs with the indicating member (He, 12e) with respect to one another as a body by means of an adhesive (13) in such a way that the reflection films (11b) 12b) are opposite one from the other. 15. A method of manufacturing an optical disc comprising: a step (Sil) of forming substrates of light transmissive discs (Ha, 12a) having a common central hole (10) and registration regions in radially intermediate regions that have bites representing the registration information being transferred to the registration regions by means of a punch, and forming a recess portion (lid, 12d) recessed in a thickness direction in a portion of at least one of the substrates disc transmissive light (Ha, 12b) around the central hole (10); a step (S12) for providing reflection films (11b, 12b) on the surfaces of the light transmissive disc substrates (Ha, 12a) that are provided with the stings; a step (S14) for providing an indication member (He, 12e) by printing and adhering on the lower surface of the recess portion (lid, 12d) on at least one of the light transmissive disc substrates (Ha, 12a) that are provided with the reflection films (11b, 12b); a step for fixing the first and second optical discs (11, 12) having the indicating member (He, 12e) one on the other as a body by means of an adhesive in such a way that the reflection films are opposite one to the other. with respect to the other. 16. A method of manufacturing an optical disk comprising: a step (Sil) to form light transmissive disc substrates (Ha, 12a) having a common central hole (10) and recording regions in radially intermediate regions with pitting which represent that the registration information is being transferred to the recording regions by means of a punch, and form a recess portion (lid, 12d) recessed in a thickness direction in a portion of at least one of the substrates of transmissive light disk (Ha, 12a) around the central hole (10); a step (S12) for providing reflection films (11b, 12b) on those surfaces of the light transmissive disc substrate that are provided with the pitting; a step (S13) for providing protection films (11c, 12c) on the upper surfaces of the reflection films (lid, 12d); a step (S14) for providing an indication member (He, * 12e) by printing and adhering to the bottom surface of the recess portion (lid, 12d) on at least one of the light transmissive disc substrates (Ha , 12a) that are provided with the protection films (Ha, 12a); and a step (S15) for fixing first and second optical discs having the indication member (He, 12e) one on the other as a body by means of an adhesive (13) in such a way that the reflection films (11b, 12b) are opposite one from the other. The method according to claim 15 or 16, wherein the step (Sil) to form the light transmissive disc substrates includes a step to form an annular projection (llf, 12f) that serves as a separator in a portion of an external surface corresponding to the indication member (He, 12e). 18. The method according to claim 15 or 16, wherein the passage (Sil) to form the transmissive disc light substrates includes a step to form an annular projection that serves as both a separator and a lens portion in a portion of an external surface corresponding to the indication member (He, 12e). 19. An apparatus for manufacturing an optical disk wherein a first and second optical discs having annular light transmissive disc substrates having a common central hole and recording regions in radially pitted intermediate regions are provided which represent that the registration is transferred to the recording regions by means of a punch, reflection film that are provided on those surfaces of the light transmissive disc substrates that are provided with the pits, an indication member is provided by printing and adhesion in at least those sides of the light transmissive disc substrates that are provided with the reflection films, and in a portion around the central hole, and an adhesion apparatus is provided for adhering the first and second optical discs having the means of indication one with respect to the other as a body by means of an adhesive or in such a way that the reflection films are opposite one with respect to the other, characterized in that the adhesion apparatus includes disc-like elastic members (211, 221) which are provided on the mutually oriented sides of the first and second plates. of pressure (210, 220) for pressing the outer surfaces of the first and second optical discs, those portions of the elastic members that are oriented towards the indication members (He, 12e) are formed of a softer material than a material of the other portions of the elastic members. 20. An apparatus for manufacturing an optical disk wherein first and second optical discs are provided having annular light transmissive disc substrates having a common central hole and recording regions in radially intermediate regions, which have pitting representing the information of registration has been transferred to the recording regions by means of a punch, reflection films that are provided on those surfaces of the light transmissive disc substrates that are provided with the pits, an indication member is provided by printing and adhesion in at least one of those sides of the light transmissive disc substrates, which are provided with the reflection films, and in a portion around the central hole and an adhesion apparatus is provided for adhering the first and second optical discs that they have the means of indicating one in the other as a body by means of an ad This is so that the reflective films are opposite one from the other, characterized in that the adhesion apparatus includes first and second annular recess portions (21d, 22d) formed in mutually opposite surface portions of first and second plates. pressure (210, 220) for pressing the external surfaces of the first and second optical discs, whose parts of the mutually opposite surfaces correspond to the indication members (He, 12e) and first and second elastic sheets (212, 222) located at length of the mutually opposite surfaces of the first and second pressure plates (210, 220) in order to cover the first and second annular recess portions, the first and second optical discs being fixed between the first and second elastic and fixed sheets one in the other.