JP2005302193A - Disk-shaped optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk-shaped optical recording medium which hardly slips when being handled by user's finger. <P>SOLUTION: In the optical disk 10, an information recording surface 13 provided on at least one disk surface of a disk-shaped base body is covered by a light transmission layer, a center hole 15 is provided in the center part of the disk-shaped base body and a concentric rough surface 9 is provided on the surface in the vicinity of the center hole. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a disc-shaped optical recording medium having a light transmission layer and a center hole covering an information recording surface.

  Conventionally, a DVD (Digital Versatile Disc) is known as a disc-shaped optical recording medium in addition to a CD (Compact Disc). Both optical discs have a uniform outer diameter of 120 mm and a thickness of 1.2 mm. Uses laser light shorter than CD with a wavelength of about 650 nm as irradiating light, and by making the numerical aperture of the objective lens 0.6 and larger than CD, it is possible to record / reproduce information with higher density and higher capacity than CD. . An optical disc has a tendency that coma aberration occurs due to the tilt (warp) of the disc as the wavelength of the irradiation light is short and the numerical aperture of the lens increases, so that the information recording / reproducing accuracy tends to decrease. By setting the thickness to 0.6 mm, which is half of the CD, a margin for the tilt (warp) of the disc is secured, and the recording / reproducing accuracy of information is maintained.

  Recently, development has been carried out with the aim of further increasing the density of a disk-shaped optical recording medium, and a high-density optical disk such as a Blu-ray disk having a recording density higher than that of a DVD has been put into practical use. Such a high-density optical disc uses, for example, a blue-violet semiconductor laser having a light transmission layer (cover layer) thickness of 0.1 mm, a wavelength of about 405 nm, and an objective lens having a numerical aperture of about 0.85. The information can be recorded about five times more than DVD with an optical disk having the same diameter of 120 mm as DVD.

  Each of the optical disks described above has a central hole having a diameter of 15 mm, for example. When recording or reproducing an optical disk, the optical disk is mounted on a recording / reproducing apparatus, and the optical disk is chucked using the central hole in the apparatus. In addition, when the optical disk is housed and stored in the case, the center hole is engaged with and fixed to the holding protrusion of the case. Such a center hole is formed by punching or the like in the optical disk manufacturing process (see Patent Document 1 below).

When the optical disk is mounted in the apparatus as described above or accommodated in a case, the optical disk is usually handled by the user's finger while avoiding the information recording surface of the optical disk. May occur.
JP 2004-39149 A

  An object of the present invention is to provide a disk-shaped optical recording medium that is less likely to slip when a user handles it with a finger.

  To achieve the above object, a disc-shaped optical recording medium according to the present invention covers an information recording surface provided on at least one disc surface of a disc-shaped substrate with a light-transmitting layer and is centered on the central portion of the disc-shaped substrate. A disc-shaped optical recording medium provided with holes, wherein a rough surface concentric with the center hole is provided on a surface in the vicinity of the center hole.

  According to this disk-shaped optical recording medium, when the user handles the disk-shaped optical recording medium, it becomes difficult to slip by handling the concentric rough surface provided on the surface near the center hole with a finger, so that dropping or the like can be prevented.

  In the disk-shaped optical recording medium, it is preferable that the rough surface is formed on the surface of the light transmission layer corresponding to a region having no information recording surface on the disk surface. The rough surface is preferably formed with a predetermined width from the inner periphery of the center hole. Moreover, it is preferable that the area | region in which the said rough surface was provided is opaque.

  According to the disk-shaped optical recording medium of the present invention, it becomes difficult for the user to slip when handling with a finger, and the disk-shaped optical recording medium can be prevented from falling.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a plan view of an optical disc according to the present embodiment. FIG. 2 is a cross-sectional view of the optical disk of FIG.

  As shown in FIGS. 1 and 2, an optical disk 10 as a disk-shaped optical recording medium according to the present embodiment includes a disk-shaped substrate 11, an information recording surface 13 provided on one surface of the substrate 11, A light transmission layer 12 provided so as to cover the information recording surface 13 and a center hole 15 provided in the center of the disk-shaped substrate 11 are provided.

  As shown in FIG. 1, the information recording surface 13 is provided in a disk-shaped region from the outer periphery 13 a near the outermost periphery of the disk-shaped substrate 11 to the inner periphery 13 b near the center hole 15. As shown in FIGS. 1 and 2, a rough surface 9 concentric with the center hole 15 is formed with a predetermined width from the inner periphery of the center hole 15. The concentric rough surface 9 is formed in a ring shape in a region near the center hole 15 inside the inner periphery 13b of the information recording surface 13, and has a rough surface with a feeling of roughness when touched with a finger. Although it can be formed by various methods, for example, it can be formed by applying ultrasonic vibration.

  1 and 2 will be described with reference to FIGS. 3 to 9. FIG. 3 is a cross-sectional view (a) of the main part of the substrate of the optical disk of FIGS. 1 and 2 and a cross-sectional view (b) of the main part of the substrate on which the light transmission layer is formed. 4 to 8 are cross-sectional views showing the main part of the punching process in the optical disk manufacturing process. FIG. 9 is a cross-sectional view of the main part of the optical disk obtained by the punching process of FIGS.

  First, the base body 11 is manufactured by resin molding. By injecting molten resin such as polycarbonate into a pair of molding dies (not shown), the base 11 is formed into a disk shape having a diameter of 120 mm and a thickness of 1.1 mm, for example. As shown in FIG. 3A, the disk-shaped substrate 11 has a circular recess 15a formed in a recess at the center of the opposite surface of the information recording surface 13, and a diameter larger than the circular recess 15a protruding toward the information recording surface 13 side. And a small circular protrusion 15b having a hole 15c at the center.

  The circular recess 15a becomes the center hole 15 through a subsequent process, but the lower portion (lower side in FIG. 2) of the vertical wall 17 of the center hole 15 in FIG. 2 is formed when the circular recess 15a is formed. At the time of molding, predetermined fine irregularities are formed on the information recording surface 13 by a stamper (not shown) disposed in the molding die. The information recording surface 13 is formed in a disk-shaped region between the outer periphery 13a and the inner periphery 13b in FIG. In addition, instead of polycarbonate, a resin such as acrylic or epoxy may be used as the molding resin.

  Next, a functional layer is formed on the information recording surface 13 of the disk-shaped substrate 11. For example, when the optical disk 10 is an information reproduction type, a reflective layer is formed on the information recording surface 13 as a functional layer. When the optical disk 10 is a type capable of recording / reproducing information, a reflective layer and a recording layer are formed on the information recording surface 13 in this order as functional layers. The reflective layer is made of Al, Ag, Au, or the like, and can be formed by a sputtering method, a vapor deposition method, or the like. The recording layer is made of a phase change material, a dye material, a magneto-optical material, or the like, and can be formed by a sputtering method, a spin coating method, an evaporation method, or the like.

  Next, as shown in FIG. 3B, the light transmission layer 12 is formed on the information recording surface 13 of the disk-shaped substrate 11 by spin coating. That is, the substrate 11 is horizontally arranged and rotationally driven, and a predetermined amount of ultraviolet curable resin is supplied around the small circular protrusion 15b of the substrate 11 from above, and centrifugal force acts on the resin to cause the resin to move in the radial direction. It is urged to the outside and spreads over the entire information recording surface 13. It is preferable that the resin can be spread easily and uniformly by dropping the resin around the small circular protrusion 15b of the substrate 11 and performing spin coating. Thereafter, the resin is cured by ultraviolet irradiation to form a flat light transmission layer 12 having a thickness of, for example, 0.1 mm on the information recording surface 13.

  Next, as shown in FIG. 3B, the center hole 15 is formed in the base 11 on which the light transmission layer 12 is formed. That is, as shown in FIG. 4, a lower pressing jig 23 made of a ring-shaped cylindrical member having a hole 23a having a diameter larger than that of the circular recess 15a is brought into contact with the back surface 11a of the base 11 to thereby make the base 11 Hold.

  Next, as shown in FIG. 5, the upper pressing jig 24 is lowered to push the cut forming blade portion 24 b of the pressing jig 24 into the light transmission layer 12. In this case, since the cut forming blade portion 24b is slightly higher than the thickness of the light transmitting layer 12, the flat bottom surface 24c of the pressing jig 24 is brought into contact with the surface 14 of the light transmitting layer 12, The cutting edge of the cutting forming blade portion 24 b reaches the surface of the base 11. Thereby, a circular cut equal to the diameter (for example, 16 mm) of the cut forming blade portion 24b is formed in the light transmission layer 12.

  Further, as shown in FIG. 5, the upper holding jig 24 has an insertion hole for allowing a punched piece punched by a punching blade portion 25 to be described later to be inserted and removed to the outside when the center hole 15 is formed. 24a is formed at the center and formed into a cylindrical shape as a whole, the circular cutting edge of the cutting blade portion 24b is formed protruding from the lower end of the insertion hole 24a, and the holding jig 24 is formed flat. The lower surface 24c thus formed is formed concentrically on the outer periphery of the cutting forming blade portion 24b.

  Next, while maintaining the state of FIG. 5, as shown in FIG. 6, the punching blade portion 25 inserted into the circular recess 15 a of the base 11 is raised through the hole 23 a of the lower pressing jig 23, and the blade portion The blade main body 26 is vibrated by generating an ultrasonic wave by an ultrasonic generator (not shown) provided below the punching blade 25 having the main body 26 at the tip and transmitting the ultrasonic wave to the blade main body 26. At this time, as shown in FIG. 6, the abutting portion 27a of the positioning convex portion 27 of the punching blade portion 25 is urged upward in the drawing by the urging member S such as a coil spring, so Even if the center of the punching blade 25 and the center hole 15c of the base 11 are misaligned, the upper end of the contact portion 27a is fitted into the hole 15c. By doing so, the punching blade portion 25 moves relative to the base body 11, and the center of the punching blade portion 25 and the center of the base body 11 coincide.

  The positioning convex portion 27 has a shaft 27b located in the hole portion 25a at the center of the punching blade portion 25, and a contact portion 27a is connected to the tip end side of the shaft 27b. Thus, a biasing member S such as a coil spring disposed around the shaft 27b biases the contact portion 27a upward in the drawing.

  Next, by raising the punching blade portion 25 from the state shown in FIG. 6 to bring the blade portion body 26 into contact with the bottom surface of the circular recess 15a and further raising it, as shown in FIG. The cutting edge is pushed into the base 11. At this time, since the blade body 26 is vibrated by ultrasonic waves by an ultrasonic wave generator (not shown) provided below the punching blade 25, the blade body 26 is smoothly pushed into the base 11. In addition, the ultrasonic waves from the blade body 26 can pass through the base 11 and further to the upper pressing jig 24 through the flat lower surface 24c of the pressing jig 24 in contact with the surface 14 of the light transmission layer 12. However, the ultrasonic waves generate vibration between the surface 14 of the light transmission layer 12 and the flat lower surface 24c. Therefore, a concentric rough surface 9 corresponding to the concentric shape of the lower surface 24c is formed on the surface 14 of the light transmission layer 12 in contact with the concentric flat lower surface 24c as shown in FIG.

  Next, by further raising the punching blade portion 25, the cutting edge of the blade portion main body 26 reaches the surface 14 of the base body 11, and as shown in FIG. 8, a portion 11b in the vicinity of the circular small protrusion 15b from the base body 11 is obtained. Are punched out to form the center hole 15 shown in FIGS. At this time, since the cut is formed in the light transmitting layer 12 by the cut forming blade portion 24b, when the cutting edge of the blade main body 26 reaches the surface 14, the light transmitting layer inside the cut forming blade portion 24b. Twelve central portions 12 a are peeled off from the base 11. Thus, as shown in FIG. 9, the center hole 15 has the inclined surface 16 having an inclination angle corresponding to the inclined outer peripheral side surface of the cutting forming blade portion 24b on the surface 14 of the light transmission layer 12, and The diameter is larger than the back surface 11a side.

  The optical disc 10 obtained as described above is completed by applying a predetermined print or the like on the back surface 11a side.

  As described above, according to the optical disk 10 of the present embodiment, the concentric rough surface 9 is the surface 14 having a predetermined width from the inner periphery of the center hole 15 and inside the inner periphery 13b of the information recording surface 13. By providing, when the user handles the optical disk 10 in a case or when it is mounted on or removed from the recording / reproducing apparatus, the concentric rough surface 9 provided on the surface near the center hole 15 is handled with a finger. It becomes difficult to slide, and the optical disk 10 can be prevented from falling.

  As described above, the concentric rough surface 9 in the vicinity of the center hole 15 can be formed by applying ultrasonic vibration to the surface 14 of the light transmission layer 12 in the punching process of the center hole 15. In the process, the blade body 26 of the punching blade 25 is vibrated with ultrasonic waves so that it can be smoothly pushed into the substrate 11, and the effects in the manufacturing process can be obtained together.

  Further, the rough surface 9 is formed in a ring shape as shown in FIG. 1, but its width (outer diameter) corresponds to the shape of the lower surface 24c formed flat in the pressing jig 24 of FIG. By changing the shape of the lower surface 24c, the rough surface 9 can be formed with a predetermined width (outer diameter).

  In addition, since the ring-shaped rough surface 9 is formed around the central hole 15 of the transparent substrate 11, the region where the rough surface 9 is provided becomes opaque. It can be visually confirmed that the punching process is completed. Therefore, process management can be performed using the ring-shaped rough surface 9 of the optical disc 10 as a mark of completion of the punching process.

  As described above, the best mode for carrying out the present invention has been described. However, the present invention is not limited to these, and various modifications are possible within the scope of the technical idea of the present invention. For example, the concentric rough surface may be provided on the back surface 11 a side of the base 11 of the optical disk 10.

  Further, the position of the concentric rough surface 9 of the optical disk 10 is not limited to the position of FIG. 1, and may be an inner region on the side of the center hole 15 on the inner periphery 13 b of the information recording surface 13 of FIG. A ring-shaped region having a predetermined width along the inner periphery 13b in the inner region may be a rough surface, and the entire ring-shaped region between the inner periphery 13b and the center hole 15 may be a rough surface.

  The optical disc 10 is a single-sided type having an information recording surface on only one side, but the present invention is not limited to this, and may be a double-sided type having an information recording surface on both sides. is there.

It is a top view of the optical disk by this Embodiment. It is sectional drawing of the optical disk of FIG. FIGS. 3A and 3B are a cross-sectional view of a main part of the base body of the optical disc of FIGS. 4 to 8 are cross-sectional views showing the main part of the punching process in the optical disk manufacturing process. FIG. 3 is a cross-sectional view of the main part showing a state in which the base 11 is held by bringing the lower pressing jig 23 into contact with the back surface 11a of the base 11 in the punching process of the optical disk manufacturing process of FIGS. FIG. 5 is a cross-sectional view of a main part showing a step of forming a circular cut of the light transmission layer 122 formed in the base body 11 by lowering the upper pressing jig 24 following the step of FIG. 4. FIG. 6 is a cross-sectional view of a main part showing a state in which the punching blade portion 25 is inserted into the circular concave portion 15a of the base body 11 and raised following the step of FIG. Following the process of FIG. 6, the punching blade 25 is further raised and the blade body 26 is pushed into the base body 11 while being ultrasonically vibrated, and the surface 14 of the light transmitting layer 12 that is in contact with the concentric flat lower surface 24 c. It is principal part sectional drawing which shows the process of forming the concentric circular rough surface 9. FIG. 8 is a cross-sectional view of an essential part showing a state in which the punching process is completed by the punching blade section 25 following the process of FIG. 7. It is principal part sectional drawing of the optical disk obtained by the punching process of FIG. 4 thru | or FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 9 Rough surface 10 Optical disk 11 Disc-shaped base | substrate 12 Light transmissive layer 13 Information recording surface 13a Outer periphery 13b Inner periphery 14 Surface 15 Center hole

Claims (4)

A disk-shaped optical recording medium in which an information recording surface provided on at least one disk surface of a disk-shaped substrate is covered with a light transmission layer and a central hole is provided in the center of the disk-shaped substrate,
A disc-shaped optical recording medium, wherein a rough surface concentric with the center hole is provided on a surface in the vicinity of the center hole. 2. The disc-shaped optical recording medium according to claim 1, wherein the rough surface is formed on a surface of the light transmission layer corresponding to a region having no information recording surface on the disc surface. The disk-shaped optical recording medium according to claim 1, wherein the rough surface is formed with a predetermined width from an inner periphery of the center hole. 4. The disc-shaped optical recording medium according to claim 1, wherein the roughened area is opaque.

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