JP2001067730A - Optical disk and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly mold a protection projection to have a prescribed bulged height on a disk surface using an ultraviolet ray-curable resin by forming the protection projection by dropping the ultraviolet ray-curable resin onto the disk surface surrounded by two lines of circular recessed grooves provided on a disk substrate. SOLUTION: The protection projection 11 for protecting an information reading surface 9 of an optical disk 1 is formed in a space area 6 between a cramping area 5 and an information recording area 3 on a surface 9 side so that it is surrounded by two lines of circular recessed grooves 12 and 12. Two lines of minute recessed grooves 12 and 12 are formed by using parallel cutter edges while rotating the disk 1. The projection 11 having no variation of its height and high liability can be formed by dropping the ultraviolet ray- curable resin onto the disk 1 surface surrounded by the grooves 12 and 12 so that the ultraviolet ray-curable resin does not flow out of the prescribed area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk such as a compact disk (CD) and a digital versatile (video) disk (DVD), and a method of manufacturing the same.

[0002]

2. Description of the Related Art An example of this type of conventional optical disk is shown in FIG.
4 shows a state where the right half of the optical disk is omitted from the center.

The optical disk 1 has an information recording area 3 formed on a disk-shaped disk substrate 2 made of a transparent synthetic resin such as polycarbonate. For example, when the optical disk 1 is a CD, information pits are formed on one surface of the disk substrate 2 and a reflection film is formed on the information pits.
Its surface is protected by a protective layer. When the optical disk 1 is a single-sided DVD, a reflective film is formed on information pits formed on one surface of the disk substrate, and a dummy disk substrate is formed on the reflective film via an ultraviolet-curable transparent adhesive. Superimposed.

[0004] The optical disc 1 has a clamping hole 4 formed at the center thereof and a clamping area 5 around the clamping hole 4. And
The information recording area 3 described above is provided on the outer peripheral side of the clamping area 5 with a space area 6 therebetween, and the outer peripheral side of the information recording area 3, that is, the outer peripheral portion of the optical disk 1 is left as a portion where the information recording area 3 is not formed. It is.

[0005] In the optical disk 1 configured as described above, the disk surface opposite to the side on which the information recording area 3 is formed becomes the information reading surface 9. By irradiating the information recording area 3 through the substrate 2,
Recording or reproduction of information is performed.

Here, the information reading surface 9 of the optical disc 1
Must be protected from scratches or the like so that information can be recorded and reproduced accurately. For this reason, for example, a ring-shaped protection projection 10 is formed on the information reading surface 9 side of the optical disc 1, for example, in a space area 6 between the clamping area 5 and the information recording area 3. The protruding height of the protection projection 10 is 0.1 to 0.2 m.
m.

[0007] The formation of the protective projections 10 allows, for example,
At the stage of commercializing optical disks, multiple optical disks 1
When the optical discs are superimposed, the optical discs come into contact with each other via the protective projection 10, so that the information reading surface 9 does not come into contact with another disc surface, and the information reading surface 9 is not damaged. Etc. can be prevented from occurring.

The protection projection 10 is usually formed integrally with the disk substrate 2 at the same time as the injection molding. In this case, since the portion having the protection projection 10 is thicker than the other disk substrates, the disk substrate cannot be uniformly cooled in the mold. For this reason, when the disk substrate is taken out of the mold and cooled naturally, a partial difference occurs in the contraction of the disk substrate, causing distortion in the disk substrate, causing birefringence and warpage, and increasing the product yield of the optical disk. Is reduced.

[0009] Therefore, one of the measures to solve the above-mentioned problem is as follows.
One measure is to form a plurality of land-shaped (or circle-shaped) protection projections 10a by dropping an ultraviolet-curable resin onto the disk substrate 2 with a nozzle after the disk substrate is formed as shown in FIG. Kaihei 10-1060
No. 44 is proposed. As another countermeasure, the protection projection 10b is screen-printed using an ultraviolet-curable resin on the disk substrate 2 or is formed by an inkjet method.
Has been proposed in JP-A-11-102912.

[0010]

However, in the method in which the ultraviolet-curable resin is dropped onto the disk substrate 2 by a nozzle, the ultraviolet-curable resin flows out of the area where the protective projections 10a are formed without flowing to the area where the protective projections 10a are formed. There is a problem that it is difficult to uniformly form the protection projection to a predetermined height, and the product yield of the optical disc is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an optical disk in which protective projections can be uniformly formed at a predetermined height using a UV-curable resin on the disk surface. And a method for producing the same.

[0012]

In order to achieve the above object, an optical disk according to the present invention is provided with two annular grooves on a disk substrate, and an ultraviolet light is applied to the disk surface surrounded by the two grooves. The protective projection is provided by dropping a curable resin.

Further, in the method of manufacturing an optical disk according to the present invention, two annular grooves are formed on the disk substrate after the molding, and an ultraviolet curable resin is coated on the disk surface surrounded by the two grooves. The disk substrate is dropped while being rotated to form a raised shape, and then the ultraviolet curable resin is cured by irradiation with ultraviolet light.

According to the above-described optical disk and the method of manufacturing the same, the ultraviolet-curable resin dropped onto the disk substrate is not blocked by the groove and flows out of the groove. It can be formed in a raised shape on the enclosed disk surface.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an optical disk and a method for manufacturing the same according to the present invention will be described with reference to the drawings.

FIG. 1 is a side view of the optical disc with the right half omitted from the center, and FIG. 2 is a plan view of the entire optical disc. The same components as those of the conventional optical disc described with reference to FIG. A description is given below.

The optical disk 1 has an information recording area 3 formed on a disk-shaped disk substrate 2 made of a transparent synthetic resin such as polycarbonate. For example, when the optical disk 1 is a CD, information pits are formed on one surface of the disk substrate 2 and a reflection film is formed on the information pits.
Its surface is protected by a protective layer. When the optical disk 1 is a single-sided DVD, a reflective film is formed on information pits formed on one surface of the disk substrate, and a dummy disk substrate is formed on the reflective film via an ultraviolet-curable transparent adhesive. Superimposed.

A clamping hole 4 is formed at the center of the optical disc 1 described above.
Has a clamping area 5 around it. The information recording area 3 is provided on the outer peripheral side of the clamping area 5 with a space area 6 therebetween. The outer peripheral side of the information recording area 3, that is, the outer peripheral portion of the optical disc 1 is a portion where the information recording area 3 is not formed. Has been left as.

In the optical disk 1 configured as described above, the disk surface opposite to the side on which the information recording area 3 is formed becomes the information reading surface 9, and a light beam is emitted from the optical pickup from the information reading surface 9 to the disk. By irradiating the information recording area 3 through the substrate 2,
Recording or reproduction of information is performed.

The protection projection according to the present invention for protecting the information reading surface 9 of the optical disk 1 is indicated by the reference numeral 11, and the protection projection 11 is formed by the clamping area 5 and the information recording area 3 on the information reading surface 9 side. Are formed in a ring shape so as to be surrounded by two annular recessed grooves 12, 12 in a space area 6 therebetween.

Next, a series of procedures from the manufacture of the optical disk 1 to the formation of the protection projection 11 will be described by taking a CD (compact disk) as an example.

First, the manufacturing process of the optical disk 1 will be described with reference to FIG. First, as shown in FIG. 3A, a transparent resin such as polycarbonate is injected and injected into a mold, and the stamper 13 forms the disk substrate 2 on which information pits 14 are formed on one surface.

Next, a reflective film 15 is formed on the entire surface of the disk substrate 2 including the information pits 14 as shown in FIG. 3B, and thereafter the protective layer 1 is formed on the reflective film 15 as shown in FIG.
6 is formed to protect the reflection film 15. The surface of the protective layer 16 is formed as a flat flat surface.

In the optical disk 1 thus manufactured, the disk surface opposite to the molding surface of the information pits 14 covered with the protective layer 16 becomes the information reading surface 9, and the surface on the protective layer 16 side displays a display or the like. Surface 17 (see FIG. 3D).

Next, after the optical disk 1 is formed, the protection projection 11 is formed. First, the optical disk 1 has two cutter blades 1 parallel to the disk surface of a space area 6 between the clamping area 5 on the information reading surface 9 side of the optical disk 1 and the information recording area 3 as shown in FIG.
By hitting 8, 18 and rotating the disc,
Two annular fine concave grooves 12, 12 are formed.

FIG. 5 is an enlarged view of this state. The cutter blade 18 has a blade width of several tens of μm and is processed into a single blade, and the interval between the two cutter blades 18 is about 1 mm. The depth of the groove formed by the cutter blades 18 is about 10 μm.

Here, an example of an apparatus for forming the concave grooves 12 in the optical disk 1 will be described. Two cutter blades 1
8 and 18 are detachably fixed to the chuck portion 20 of the holder 19. The holder 19 is supported by the fixed block 21 so as to be able to swing vertically about a fulcrum shaft 22. A frame 23 is fixed to the fixed block 21,
One end of a tension coil spring 24 is supported by the frame 23, and the other end of the tension coil spring 24 is
Are supported by a pin 25 standing upright. The fixed block 21 is attached to an elevating mechanism (not shown) via an attachment frame 26.

On the other hand, the optical disk 1 is held on a chucking table 27 using the clamping hole 4, and the chucking table 27 is driven to rotate by a spindle motor 28.

The operation for forming the concave grooves 12 in the optical disk 1 is performed by lowering the cutter blades 18 and 18 together with the fixed block 21 on the optical disk 1 that is being driven to rotate, and moving the tips of the cutter blades 18 and 18 to the optical disk 1. By contacting the surface, two annular concave grooves 12, 12 are formed.
The groove depth of the concave groove 12 formed on the optical disk 1 is determined by the spring force of the tension coil spring 24,
The pressing force of 18 is adjusted.

The protection projection 11 is formed on the optical disc 1 on which the two annular grooves 12 are formed. When the optical disc 1 is rotated at a low speed by a chucking table (not shown) when forming the protective projection 11, a predetermined amount of the nozzle 29 is formed on the disc surface surrounded by the two grooves 12, 12 as shown in FIG. The ultraviolet curable resin 11a is dropped. As a result, the ultraviolet-curable resin 11a is annularly applied to the disk surface surrounded by the grooves 12,12.

FIG. 8 is an enlarged view of the optical disc 1 on which the ultraviolet curable resin 11a is applied. That is, the ultraviolet curable resin 11a dropped on the surface of the optical disk 1 is such that a part of the resin flows into the grooves 12, 12, and the grooves 12 serve as weirs and do not flow outside beyond the grooves 12. .
In other words, the ultraviolet-curable resin 11a can be retained in a protruding state on the disk surface between the concave grooves 12, 12 by the action of surface tension.

The ultraviolet curable resin 11 is applied to the disk surface.
In the dropping step of a, the groove 1
Alternatively, the ultraviolet curing resin 11a may be dropped onto the disk surface at the same time as the grooved groove 12 is formed by the cutter blade 18 after the grooved step 2 is performed. By doing so, the production line can be shortened.

In this manner, the optical disk 1 coated with the ultraviolet-curable resin 11a is irradiated with the ultraviolet-curable resin 11a by the ultraviolet lamp 30 to form the solidified protection projection 11 as shown in FIG.

As described above, the projection 11 for protecting the optical disk according to the present invention is provided with two annular concave grooves 1 in advance on the disk surface.
The UV-curable resin 11a is dropped on the disk surface surrounded by the grooves 12, 12 so that the UV-curable resin 11a does not flow out of a predetermined area and is protected. A highly reliable protection projection can be formed without variation in the height of the projection 11 for protection.

Further, by forming the concave grooves 12, 12 on the disk surface, even if there are suction pad traces or slight irregularities on the disk surface, the dripped ultraviolet curable resin 11a allows the concave grooves 12, 12 to be formed. The protective projection 11 having a stable shape that is reliably blocked by the 12 can be formed.

Therefore, since the optical disk can be moved even when the protection projection 11 is not cured, the dropping process of the ultraviolet curable resin by the nozzle and the curing process by the ultraviolet lamp can be performed at different positions, and the productivity can be improved. .

In the above-mentioned optical disk, the case of a CD (compact disk) has been described as an example. However, molding of protective projections of a DVD (digital versatile disk) to which two disk substrates are bonded can be performed in the same manner. it can.

FIG. 10 is an enlarged sectional view of a DVD having one layer on one side. According to this, the reflective film 33 is formed on the information recording pits 32 formed on the disk substrate 31, and the dummy disk substrate 35 is superposed from the surface of the reflective film 33 via the ultraviolet curing adhesive 34. It is molded by.

In the single-sided single-layer DVD constructed as described above, the disk surface opposite to the dummy disk substrate 35 becomes the information reading surface 37 by the optical pickup 36, and the outer peripheral side of the clamping area on the information reading surface 37 side. Annular protective projection 1 in the space area adjacent to
1 is molded.

In addition, since the protection projection 11 is formed after the disk substrate 31 is formed, a single-sided DVD has
When an error or the like occurs in the information recording pits 32 during molding of the disk substrate 31 and the disk substrate 31 becomes defective,
This disk substrate 31 can be diverted to the dummy disk substrate 31a, thereby improving the product yield of the optical disk and reducing the production cost.

FIG. 12 is an enlarged sectional view of a DVD in the case of a single-sided double-layer. According to this, the reflective film 40 is formed on the information recording pit 39 formed on the first disk substrate 38, and the ultraviolet curable adhesive 4 is formed from the surface of the reflective film 40.
1 and the information recording pits 43 formed on the second disk substrate 42 on which the reflective film 44 is formed are laminated and adhered.

In the double-sided, single-layer DVD constructed as described above, the first disk substrate 38 and the second disk substrate 42
Are information reading surfaces 47 and 48 by the optical pickups 46 and 49, respectively. In this case, annular protection projections 11 and 11 are formed in a space area adjacent to the outer peripheral side of the clamping area on both information reading surfaces 47 and 48. Is done.

The present invention is not limited to the embodiment described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention.

In the embodiment of the present invention, the case where the annular protective projection is provided in the space area adjacent to the outer peripheral side of the clamping area in both the optical discs of CD and DVD has been described. As shown, an annular protective protrusion 11 may be provided on the outer peripheral portion 8 of the disk on the outer peripheral side of the information recording area 3 of the optical disk 1, or an annular protective protrusion may be provided on both of them. .

The above-described operation can be obtained by providing at least three land-like protection projections at regular intervals other than providing the protection projections in a ring shape. In this case, the groove at the time of the land-shaped protection projection is formed in a circular shape surrounding the land-shaped protection projection.

As a method of forming the concave groove 12 in the optical disk, a groove is formed by using a part of a mold simultaneously with the injection molding of the disk substrate, except that the groove is cut using a cutter blade. You may make it shape | mold.

Further, the protective projection is made of an ultraviolet-curable resin which is appropriately colored so that, for example, the colored protective projection has the same color as the optical disk or the protective projection has a different color from the optical disk. This makes it possible to identify the type such as the format of the optical disk from the appearance.

[0048]

As described above, according to the optical disk of the present invention, two annular grooves are provided on the disk surface other than the recording area on the information reading surface side of the disk substrate, and these two grooves are used. By providing the protection projection by dropping the ultraviolet curing resin on the enclosed disk surface, the protection projection is guided along the concave groove, and the height can be made uniform, so that the protection projection has high reliability.

According to the method of manufacturing an optical disk according to the present invention, two annular fine concave grooves are formed on the disk surface other than the recording area on the information reading surface side of the disk substrate. UV curable resin was dropped by a nozzle on the disk surface surrounded by the groove of the groove to form a protruding shape, and then the UV curable resin was cured by irradiation with ultraviolet light to form protective projections. ,
The ultraviolet curable resin is not blocked by the groove and does not flow out of the groove, so that there is an effect that a protective projection having a stable shape and a uniform height can be formed.

[Brief description of the drawings]

FIG. 1 is a side view of an optical disc according to the present invention, in which a right half from a center is omitted.

FIG. 2 is an overall plan view of the optical disk according to the present invention as viewed from a protection projection side.

FIG. 3 is a manufacturing process diagram of an optical disk as a CD.

FIG. 4 is a process diagram of forming a concave groove on an optical disk by a cutter blade.

FIG. 5 is an enlarged view of an optical disk and a cutter blade.

FIG. 6 is a side view of the cutter blade device.

FIG. 7 is a process diagram of dropping an ultraviolet curable resin from a nozzle onto a surface of an optical disc.

FIG. 8 is an enlarged view of an optical disk on which an ultraviolet curable resin is dropped.

FIG. 9 is a process chart of curing an ultraviolet-curable resin with an ultraviolet lamp.

FIG. 10 is an enlarged sectional view of a DVD having a single-sided optical disk.

FIG. 11 is an enlarged cross-sectional view in which a disk substrate due to a molding failure is diverted to a dummy disk substrate.

FIG. 12 is an enlarged cross-sectional view of a DVD having a single-sided optical disk.

FIG. 13 is a side view similar to FIG. 1 of an example in which protective protrusions are formed on the outer peripheral portion of the optical disc.

FIG. 14 is a side view of a conventional optical disk in which protective projections are integrally formed on the optical disk.

FIG. 15 is a plan view of a conventional optical disc in which protective protrusions are formed on the optical disc.

FIG. 16 is a plan view of another conventional optical disc in which protective projections are post-formed on the optical disc.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Disk board, 3 ... Information recording area, 4 ... Clamping hole, 5 ... Clamping area, 6 ... Space area, 8 ... Peripheral part of optical disk,
9 information reading surface, 11 protection protrusion, 11a ultraviolet curing resin, 12 groove, 18 cutter blade, 29
Nozzle, 30 ... UV lamp

Continuing on the front page (72) Inventor Kozo Fukasawa 1-44 Yatamachi, Shinjuku-ku, Tokyo Inside Sony Music Entertainment Inc. (72) Inventor Wataru Yoshioka 1-4-4 Yatamachi, Shinjuku-ku, Tokyo Sony Corporation In Music Entertainment (72) Takayuki Suzuki, Inventor 1-4 Term Yatacho, Shinjuku-ku, Tokyo F-term in Sony Music Entertainment Inc. 5D029 LA02 LB04 5D121 AA04 EE22 EE28 GG02

Claims (5)

[Claims] 1. An information reading surface for reading said recording area in an optical disk having a clamping area around a clamping hole of the disk and having a recording area formed on the outer peripheral side of the clamping area with a space area therebetween. The two disk-shaped fine concave grooves on the disk surface other than the recording area on the side disk surface, and the protection formed by dropping the ultraviolet curable resin on the disk surface surrounded by the two groove grooves. An optical disk characterized by comprising a projection for use. 2. The optical disk according to claim 1, wherein the concave groove and the protection protrusion are formed on an outer peripheral portion of the space area and / or the outer peripheral side of the recording area. . 3. A step of forming two annular fine grooves on the disk surface other than the recording area on the information reading surface side of the disk substrate, and rotating the disk substrate so as to be surrounded by the two grooves. A step of dropping an ultraviolet-curable resin onto the disc surface which has been formed into a raised shape, and a step of curing the raised ultraviolet-curable resin by irradiating ultraviolet rays to form protective projections. An optical disc manufacturing method. 4. The method for manufacturing an optical disk according to claim 3, wherein the two annular grooves are formed by grooving the disk surface with two parallel cutter blades after forming the disk substrate. A method for manufacturing an optical disk, comprising: 5. The method for manufacturing an optical disk according to claim 3, wherein said two annular grooves are formed by utilizing a part of a molding die simultaneously with the molding of the disk substrate. An optical disc manufacturing method.