JP3545268B2 - optical disk - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a playback apparatus for an optical disc as an optical information recording medium and an optical disc used for inspection and adjustment of a pickup in the playback apparatus, and more particularly to a playback apparatus for playing back a bonded disc such as a DVD and a pickup in the playback apparatus. Related to inspections and adjustments.
[0002]
[Prior art]
2. Description of the Related Art In a reproducing apparatus for reproducing an optical disk as an optical information recording medium, a dedicated disk (hereinafter, referred to as a test disk) is used for inspection and adjustment of a reproducing apparatus and a pickup provided in the apparatus (for example, see Japanese Patent Application Laid-Open No. -36351). The test disk is required to eliminate errors caused by the disk in the inspection and adjustment work. Generally, in an optical disk system, a physical part such as a disk shape and optical characteristics and a part relating to a signal (information) format and a modulation method, such as a so-called compact disk (hereinafter, referred to as a CD), are detailed in detail. Has been That is, the test disk is required to satisfy this standard and hardly cause physical or electrical fluctuation.
[0003]
Therefore, by using glass for the base of the test disk, the warpage and distortion (physical error / fluctuation) of the disc, or the jitter (electric fluctuation) generated due to the dull shape of the signal bit, etc., have been minimized. Things have been put to practical use. Glass is expensive to manufacture compared to polycarbonate used for the base of CD discs, but has high hardness, excellent mechanical strength, and is hardly affected by humidity and temperature. Very suitable.
[0004]
In recent years, in addition to CDs, various types of optical disk systems have been standardized and put into practical use. Test discs conforming to the respective standards are also required for inspection / adjustment work of a reproducing (or recording / reproducing) apparatus of each type. Requested. For example, even in a digital video disk (hereinafter referred to as a DVD) in which the storage information volume is increased by increasing the storage density of one disk and bonding two more disks together, the test disk described above is used. Is desired.
[0005]
FIG. 3 is a partial schematic diagram of a DVD disk. Numerals 3 and 4 denote optical disks on which information is recorded respectively, 31 and 41 denote polycarbonate bases, 32 and 42 denote optical information recording layers in which information is represented in the form of pits, and 33 and 43 denote protective layers. The protection layers 33 and 43 of the disks 3 and 4 are bonded together to form one disk A. Reading of information from each of the disks 3 and 4 is performed by irradiating a laser beam from the substrate 31 or 41 side by turning over the disk and detecting reflected light from the optical information recording layer 32 or 41, respectively. .
[0006]
By the way, according to the CD standard, the disk has an outer diameter of 12 cm, a thickness of 1.2 mm, and a mass of 14 to 33 g. For a test disk using glass as a base, the mass and the outer shape and thickness satisfy the standard. Was 33 g, which was the upper limit mass of the standard. According to the DVD standard, the outer diameter is 12 cm, and the thickness of one disc is 0.6 mm (1.2 mm when two discs are bonded), which is the same as that of a CD (for example, see JP-A-9-320109). ), But the mass is at most 20 g. For this reason, when glass is used for the base of the disk in the manufacture of the DVD test disk, the mass becomes 33 g, which is the same as the CD test disk, and the mass does not satisfy the standard. For this reason, glass could not be adopted as a DVD test disk as a substrate of the disk.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of such a point, and a material having a specific gravity whose relative weight is standardized for the external dimensions such as a DVD disk and which cannot satisfy the standard for the external dimensions is provided. The purpose is to provide a stable test disk with characteristics that have little physical or electrical fluctuation by using glass as the disk base, even if the disk is formed by using, and satisfy the mass specification. It is assumed that.
[0008]
[Means for Solving the Problems]
The optical disk of the present invention according to claim 1 is an information disk from which light incident through a light-transmissive substrate is reflected by an optical information recording layer to allow information to be read, and light from the substrate is incident. A spacer provided on a side opposite to the side to increase a clamp thickness in a clamp region where the information disk is held when information is read from the information disk, than a thickness of the information disk.
[0009]
An optical disc according to a second aspect of the present invention is the optical disc according to the first aspect, wherein the light-transmitting base is made of glass.
[0010]
According to a third aspect of the present invention, there is provided the optical disk according to the first or second aspect, wherein each of the information disk and the spacer has a thickness of approximately 0.6 mm.
[0011]
Embodiment
FIG. 1 is a schematic perspective view showing an embodiment of an optical disk according to the present invention, and FIG. 2 is a sectional view in the thickness direction of FIG. These drawings are schematically drawn for easy understanding, and are different from actual dimensions and scale ratios.
[0012]
Reference numeral 1 denotes an information disk, which is a substantial test disk, on which an optical information recording layer 12 is provided on a glass base 11 and information for testing is recorded. On the optical information recording layer 12, a protective layer 13 made of an ultraviolet curable resin such as an acrylic resin or a methacrylic resin is provided, and the thickness of the base 11 is equal to that of one DVD disk (one layer). The thickness of the protective layer 13 is treated as a substantially thin layer in view of the thickness ratio. The information disc 1 is a disc having a diameter of 12 cm, and a center hole H having a hole diameter of 15 mm is provided at the center at the center of the information disc 1, and the center of the information disc 1 is also outside the center hole H. Between the inner diameter of 26 mm and 33 mm, a clamp area C which is held by a clamp mechanism of an information reproducing device (not shown) when reading information from the information disk 1 is formed.
[0013]
2 is formed of a relatively light and hard resin such as polytetrafluoroethylene, for example, and is provided on the protective layer 13 side of the information disk 1, that is, on the side of the base 11 opposite to the side on which the laser beam is incident. Spacer for increasing a clamp thickness in a clamp area held by a clamp mechanism of an information reproducing apparatus (not shown). The spacer 2 is formed in a disk shape having an outer diameter smaller than that of the information disk 1, has a hole having the same diameter as the center hole H, has a thickness of 0.6 mm, and has an outer diameter of the clamp area C of the information disk 1 (33 mm in diameter). ) Has almost the same size. In this embodiment, the outer diameter is set to 34 mm in consideration of errors in the dimensional accuracy of the spacer 2 and the bonding accuracy to the information disk 1 and the like. The spacer 2 is bonded and fixed to the protective layer 13 with the center of the spacer 2 and the center of the information disk 1 aligned. Note that the clamp thickness means the thickness in the clamping direction of an object to be clamped by a clamp mechanism of an information reproducing apparatus (not shown) when reading information from the information disc 1, and the thickness of the information disc 1 and the spacer 2 in the present invention. means.
[0014]
The mass of the glass information disk 1 having a diameter of 12 cm and having the center hole H was approximately 17.63 g, and the mass of the spacer 2 was approximately 1.12 g, which was 18.75 g as a whole. Therefore, the standard of the mass of DVD is satisfied. Further, since the base 11 of the disk 1 is made of glass, physical or electrical fluctuations are less likely to occur, and errors caused by the configuration of the disk are eliminated as much as possible.
[0015]
Thus, when performing inspection or adjustment work on the reproducing apparatus and the pickup provided on the apparatus using the disc of the present invention having the spacer, the laser beam for reading information is optically recorded on the optical information recording medium through the base 11. The disc shown in FIG. 1 is mounted on a playback device (not shown) so that the light is incident on the layer 12. At this time, the DVD disc has a thickness of 1.2 mm according to the standard, and if the clamp thickness of the apparatus is set so that the disc having a thickness of 1.2 mm can be properly clamped, the disc is shown in FIG. The disc shown is clamped without hindrance. Then, the reproducing apparatus is driven to read and reproduce the information recorded on the optical information recording layer 12, and it is checked whether or not a good reproduced signal can be obtained. . Whether a good reproduction signal is obtained is determined by detecting an eye pattern, jitter, or whether the same information as recorded information can be reproduced.
[0016]
In the case of a DVD disc, as shown in FIG. 3, discs having the same configuration (recorded information is different) are stuck on the protective layer side, and in most cases (a pickup is provided on both sides of the disc). Since the disk surface (substrate side) to be reproduced is mounted with the pickup side facing the pickup side, when reading and reproducing information, it does not matter whether information is read from either side. The distance from the substrate to the optical information recording layer is the same 0.6 mm. Therefore, the inspection and adjustment work of the reproducing apparatus using the test disk and the pickup provided in the apparatus need only be performed on one side, so that the test disk shown in FIG. 1 enables more accurate inspection and adjustment work.
[0017]
In this embodiment, the spacer 2 is made of polytetrafluoroethylene. However, the spacer 2 is not limited to this, and may be made of, for example, a resin that is relatively hard and easily secures surface accuracy. Is also good. When a spacer having the same size as that of the spacer 2 is made of glass, its mass is 1.16 g, which is 18.79 g when combined with the information disk 1, and can also satisfy the DVD mass standard.
[0018]
In this embodiment, the outer diameter of the spacer 2 is set to be substantially the same as the outer diameter of the clamp area C (34 mm). However, if the specification of the mass is satisfied, the spacer includes the clamp area and is larger than the outer diameter of the information disk. The outer diameter may be within a small range.
[0019]
The present invention is not limited to DVD discs, and is effective for meeting the mass standard when a test disc is made of a material that cannot meet the mass standard for the external dimensions of the disc. It is applied to
[0020]
【The invention's effect】
As is clear from the above description, the present invention uses glass as the base of the information disk, and adjusts the clamp thickness in the clamp area of the information disk on the side opposite to the side on which light is incident on the base, that is, on the protective layer side. By providing a spacer that is larger than the thickness of the information disc, even if a material that cannot meet the mass standard for the external dimensions of the disc is used for the base, it is possible to satisfy the mass standard, and Thus, it is possible to supply a stable test disk having a characteristic with little change in electrical or electrical characteristics. As a result, inspection and adjustment work of the disc reproducing apparatus and the pickup provided in the apparatus can be accurately performed.
FIG. 1 is a schematic perspective view showing one embodiment of an optical disc according to the present invention.
FIG. 2 is a sectional view in the thickness direction of FIG.
FIG. 3 is a schematic configuration diagram of a DVD disk.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Information disk 11 Base 12 Optical information recording layer 13 Protective layer 2 Spacer

Claims (3)

An information disk capable of reading information by reflecting light incident through a light-transmitting substrate on an optical information recording layer;
A spacer provided on the side of the base opposite to the side on which light is incident, the spacer being configured to make the clamp thickness in the clamp area where the information disk is held when information is read from the information disk larger than the thickness of the information disk. An optical disc characterized by the following. The optical disc according to claim 1, wherein the light-transmitting substrate is made of glass. 3. The optical disk according to claim 1, wherein each of the information disk and the spacer has a thickness of approximately 0.6 mm.

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