JP2001184741A - Production of optical memory medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for simplifying the manufacture of a both side type multiple layer optical disk. SOLUTION: The disk is provided with a first substantially transparent disk having a first substantially flat surface and a second surface facing this first surface. This second surface has a first information layer for memory and a semi-reflection layer is formed on the second surface. The disk is provided with a reflection layer and a layer for removal having a substantially flat third surface having a second information layer and this third surface is arranged in a position at a prescribed distance from the second surface. A substantially transparent layer is formed between the second surface and the third surface. The layer for removal is thereafter removed from the reflection layer and the reflection layer formed on the third surface is transferred to the transparent layer, by which a fourth surface is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to information storage media such as disks having optically readable information, and more particularly to such information storage media having one or more information on one side. The present invention relates to a method for manufacturing a medium.

[0002]

[0002] Prior art information storage media typically include a single information layer on one side. For example, standard DVD-5
One-disc format, commonly known as, includes a single layer of information stored on a single side of the disc. A disc in this format has a 0.6 mm medium on which data is recorded. Alternatively, a blank substrate without the information layer is adhered to the first substrate to form a 1.2 mm thick disk. The DVD-5 format can store up to 4.7GB of information. To double the capacity of such a disc,
As mentioned above, it is possible to provide two 0.6 mm thick substrates, each having information stored thereon. The two substrates are bonded together back to back. DVD-
10 is one example of such a disc.

Another approach to increasing the storage capacity of a disk having optically readable information is to provide one or more readable layers on one side of the disk. For example, DVD-9 allows two information layers to be read from one side of the disc. A transparent substrate having a first layer of recorded information is provided, and a semi-reflective layer is applied to it. A second information layer is recorded on the second substrate, and a reflective layer is applied to the second information layer. The semi-reflective layer, due to the concentration characteristics of the laser reader,
Make both the first layer and the second layer readable. The substrate is adhered with an optically transparent layer. The performance of a single-sided double-layer DVD disc is slightly lower than a two-sided single-layer DVD-10. That is, the DVD-9 format is 8.5GB and the DVD-10 format is 9.4GB.

In order to produce a two-sided multi-layer disc such as a DVD-18, like a single-layer disc, for example,
By gluing two multi-discs together, such as two DVD-9 discs, it is possible to double the storage capacity of a multi-layer disc. While allowing a significant amount of data to be stored, two-sided multi-layer discs are difficult to manufacture.

[0005]

In view of the foregoing, it is an object of the present invention to provide a method and apparatus for simplifying the manufacture of such disks.

[0006]

These and other objects of the invention are achieved by first providing a first disk and a second disk in accordance with the principles of the invention.
The first disk has a first substantially flat surface and a first disk.
And a second surface opposite to the surface of The second surface has a first information layer stored or for storing thereon due to a local change of the second surface. A semi-reflective layer is applied to the second surface.

A shape layer is positioned adjacent to the second surface. The shape layer has a substantially flat third surface with the second information stored thereon due to local changes in the third surface. The space between the second surface and the third surface is filled with a substantially transparent layer, and the second information stored on the third surface is transferred to the transparent layer. Forms a fourth surface on the transparent layer. The shape layer is removed from the transparent layer.

[0008] In a preferred embodiment, the reflective coating is positioned prior to positioning the shaped layer adjacent to the second surface.
Applied to the third surface. The step of bonding the second surface and the third surface includes transferring the reflective layer from the shape layer to a transparent layer. In another preferred embodiment, the reflective layer is then applied to the transparent layer after the shape layer has been removed.

[0009] To form a dual-sided information storage medium, a second substantially transparent surface having a fifth substantially planar surface and a sixth surface opposite the first surface. The sixth surface on which the new disk is provided has third information stored thereon due to local changes in the sixth surface.
A semi-reflective layer is applied to the sixth surface.

[0010] A second shape layer is positioned adjacent to the sixth surface. The second shaped layer has a substantially flat seventh surface with fourth information stored thereon due to local changes in the seventh surface. The space between the sixth surface and the seventh surface is filled with a second substantially transparent layer, and the fourth information stored on the seventh surface is
In order to form an eighth surface on the second transparent layer. The second shape layer is removed from the second transparent layer. A second reflective layer is then applied to the eighth surface on the second transparent layer. Next, the first
Is adhered to the second transparent layer to form a completed information storage medium.

Further, other features of the present invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments.

[0012]

Embodiments and Examples of the Invention
Although described with respect to the D format, the principles of the present invention are applicable to all types of optically readable information storage media. An exemplary method of manufacturing an optical storage medium is shown in FIG. A first substrate 10 is provided, which is typically a substantially optically clear polycarbonate material. The first surface 12 of the substrate 10 is substantially flat. The second surface 14 of the substrate 10 has a plurality of local changes 16 on the surface 14, such as depressions, grooves or other depressions etched, stamped or molded on the surface. These local changes 16 can be read as information by optical devices known in the art.

According to the DVD format, the substrate 10 need only have a typical thickness dimension 18 of about 0.6 mm. The semi-reflective layer 20 is applied to the surface 14 of the substrate 10 by a known process such as chemical or physical vapor deposition. The pattern of the semi-reflective layer 20, which is applied to the surface 14 and has reflective characteristics, is drawn as information of the first layer. The semi-reflective layer 20 is typically made of aluminum or other material and allows for optical reading of information stored on the surface 14, while one or more of the information stored on the surface 30 described in detail below. Must be precisely controlled to allow optical reading of the The semi-reflective material properties of multilayer optically readable disks are known in the art.

The removal layer 22 is provided for transferring the second information layer onto the disc. The removal layer 22 includes
A plurality of local changes 26 are formed in surface 24, such as the depressions, grooves, or depressions described above with respect to surface 14. These local changes 26 can likewise be read as information by optical devices known in the art.
The removal layer 22 also includes a tear-off flange 28, which may be an annular rim or a series of tabs provided around the periphery of the removal layer 22. As will be described in greater detail below, the tear-off flange 28 assists in separating the removal layer 22 from other components during processing. The reflective layer 30, typically of aluminum, is applied to the surface 2 of the removal layer 22.
4 is applied.

The surface 24 of the removal layer 22 is adjacent to the surface 14 of the substrate 10 such that the surfaces 24 and 14 are substantially parallel and define a substantially uniform separation 32 of about 55 μm. Positioned, that is, placed. Adhesive layer 3
4 is applied in the space between the surface 24 and the surface 22, more specifically between the reflective material layer 30 and the semi-reflective layer 20. The adhesive is substantially transparent and is made to adhere precisely to the reflective layer 30 in order to properly mimic the recessed structure defined by the local changes 26 in the surface 24. The adhesive is curable as is known in the art.

As illustrated in FIG. 2, the removal layer 22 is separated from the adhesive layer 34 and the reflective layer 30. Removal layer 2
The two peeling flanges 28 are provided with mating surfaces to facilitate such separation. For example, the removal layer 22
A separating device, such as a trip finger 36 having an engagement surface 38 that locks to the end of the
8 is engaged. The removal layer 22 is disengaged from the reflective layer 30 by applying a force in the direction of arrow 40. Although removal of removal layer 22 is illustrated in the direction of arrow 40 substantially perpendicular to surfaces 24 and 14, removal layer 22 may be removed at any oblique angle. To assist in separating the removal layer 22, the removal layer 22 may be molded from a material such as polymethyl methacrylate (PMMA), an acrylic product, or Perspex, or a mold release additive may separate from the aluminum layer. May be used to help. The removal of the removal layer 22 from the reflection layer 30 is performed by moving the adhesive layer 34 from the removal layer 22 and removing the reflection layer 30.
Is transferred to the second layer.

After separation of the removal layer 22, the remaining components, namely the substrate 10, the semi-reflective layer 20, the adhesive layer 34 and the reflective layer 30 are collectively referred to as the first side 42 of the disk. (See Fig. 3)

The process steps described above with reference to FIGS. 1 and 2 are repeated for the second side 44 of the disk (see FIGS. 3 and 3). For example, a second semi-reflective layer 52 is formed on the second substrate 50 having the information of the third layer.
A second reflection layer 54 is formed on a second removal layer (not shown) for transferring information of the fourth layer. The reflective layers 52 and 54 are adhered together by an adhesive layer 56, and the second removal layer is removed from the reflective layer 54.

As illustrated in FIG. 3, the first side 4
2 and the second side 44 are connected to their respective substrates 10.
And 50 are glued together so that they face outward. The semi-reflective layer 20 and the reflective layer 30 are read from the direction of arrow 62,
Then, the semi-reflective layer 52 and the reflective layer 54 are read from the direction of the arrow 64. For example, DVD-18 type discs are manufactured by this method.

In addition, the disc is made up of two
It may be fabricated from a first side having a multi-layer structure and a second side having a single-layer structure, such as the side 100 illustrated in FIG. For example, the side 100 has a first base 102 and a reflective layer 104. Side 42 and side 100 are bonded together by an adhesive layer 106.

Next, another second embodiment according to the present invention is illustrated in FIG. This embodiment is substantially similar to the embodiment described above with respect to FIGS. 1 and 2, except for the following differences described below. The base 10 and the semi-reflective layer 20 are provided as described above. A removal layer 122 holding information is provided over the surface 124. A release layer 130 is applied to the surface 124 of the removal layer 122 instead of the reflective layer. An adhesive layer 34 is provided between the release layer 130 and the semi-reflective layer 20. The information structure of the surface 124 is
Is transferred to the surface 35 of. Release layer 130 is selected from materials known in the art to help separate removal layer 122 from adhesive layer 34 while adhering to the surface of removal layer 122. As a result, the removal layer 122 becomes 140
Release layer 130 when removed from adhesive layer 34 in the direction of
Remain adhered to the removal layer 122. Release layer 130
The recess formed above is properly transferred without damaging the adhesive layer upon removal of the removal layer 122. Next, a reflective layer (not shown) having characteristics similar to the reflective layer 30 is applied to the adhesive layer 34.

A third alternative embodiment according to the present invention is illustrated in FIG. This embodiment is substantially similar to the embodiment described above with respect to FIGS. 1 and 2, except for the following differences described below. The base 10 and the semi-reflective layer 20 are provided as described above. A removal layer 222 holding information is provided over the surface 224. No coating layer is formed on the surface 224. An adhesive layer 34 is inserted between the surface 224 and the semi-reflective layer 20. The removal layer 222 includes
It is removed from the adhesive layer 34 in the direction of arrow 240. The use of certain materials known in the art allows the removal layer 222 from the adhesive layer 34 without damaging the depressions in the adhesive layer 34.
Enables the separation of The depression structure formed on the adhesive layer 34 is appropriately transferred without being damaged when the removal layer 222 is removed. Next, the reflection layer 3
A reflective layer (not shown) having properties similar to 0 is formed on the adhesive layer 34.

FIG. 7 illustrates an optically readable information storage disk manufacturing apparatus 300 for carrying out the present invention. Apparatus 300 is particularly useful for positioning and removing a removal layer, such as removal layer 22, from a substrate. Base 302
Is provided to support a first layer such as the substrate 10 thereon. The center post 304 correctly positions the base 10 on the base 302. A plurality of ports 306 are distributed over the surface of base 302 to provide low air pressure or vacuum to securely attach substrate 10 to the base without the application of mechanical forces that may damage the substrate. Have been.

A member 308 is mounted for vertical movement with respect to the base 302 by the main lift cylinder 310 that activates the support arm 312. A center hold 314 and a peel assembly 316 extend from member 308. Stripper assembly 316 is mounted for vertical movement relative to member 308 by trip cylinder 318. Accordingly, the peel assembly 316
Is the center hold 31 as detailed below.
4 is controlled to move vertically. Release assembly 316 has an engaging surface 3 at one end to engage a portion of another layer, such as release flange 28 of removal layer 22.
2 having a trip finger 320 (substantially the same as the trip finger 36 of FIG. 2). Trip finger 320 is connected to trip cylinder 318 by peeling arm 324. Alternatively, peel assembly 316 may be moved by a motor or other mechanism known in the art.

The removal layer 22 is located above the substrate 10 as described above. According to a preferred embodiment, the trip fingers 320 support the removal layer 22 at the release flange 28 substantially parallel to and slightly spaced from the substrate 10 (see FIG. 1). Center hold 314
Are aligned with the center post 304 to laterally align the removal layer 22 with the substrate 10. Cushion 326 which is an annular ring is provided with center hold 314.
And the removal layer 22 to protect the removal layer from damage.

After the adhesive layer 34 has been applied between the removal layer 22 and the substrate 10, the adhesive layer is cured. Next, the removal layer 22 is removed or separated from the base 10 and the adhesive layer 34. Trip finger 320 is attached to apparatus 300 for removing removal layer 22.

As described above, the relative vertical movement of the peel assembly 316 and the center hold 314 allows for a peel process that can be performed in several ways. According to one embodiment of the present invention, the trip finger 320 engages the release flange and removes the layer 22 from the adhesive layer 34.
May be performed while the center hold 314 remains fixed. In other words, the cushion 310 provides sufficient resilience so that the removal layer 22 can move a small distance vertically relative to the center hold 314. After the first peel, the trip finger 320 and the center hold 314 are separated by the peel arm 324.
And lifted by the main lift cylinder 310 which provides upward movement to release the center hold 314. Alternatively, according to a second embodiment, the center hold 314 may be vertically separated from the removal layer 22. Next, the trip finger 320 is lifted to remove the removal layer 22 from the substrate 10. According to the third embodiment, the trip finger 320 and the center hold 31
4 may be formed to move vertically simultaneously to separate the removal layer 22 from the adhesive layer 34.

The embodiments described above are merely illustrative of the principles of the present invention. It will be understood that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. For example, while the various dimensions and materials described herein are preferred, other dimensions and materials can be used as desired.

[0029]

As described above, according to the present invention, it is possible to provide a method for simplifying the manufacture of a double-sided multi-layer optical disc.

[Brief description of the drawings]

FIG. 1 shows a simplified cross-sectional view of a disc in a first step of the method according to the invention.

FIG. 2 illustrates a simplified cross-sectional view of a disk similar to FIG. 1 in a next step of the method according to the invention.

FIG. 3 illustrates a cross-sectional view on an exemplary scale of the disc in another next step of the method according to the invention.

FIG. 4 illustrates a cross-sectional view similar to FIG. 3 of another embodiment according to the present invention.

FIG. 5 illustrates a cross-sectional view similar to FIG. 2 illustrating yet another embodiment according to the present invention.

FIG. 6 illustrates a cross-sectional view similar to FIG. 2 illustrating yet another embodiment according to the present invention.

FIG. 7 illustrates a simplified cross-sectional view of an apparatus for practicing the present invention.

[Explanation of symbols]

10, 50, 102 ... base 20, 52 ... semi-reflective layer 22, 122, 222 ... removal layer 28 ... removal flange 30, 104 ... reflection layer 34, 106 ... Adhesive layer 34 36 trip finger 130 release layer 300 optically readable information storage disk manufacturing apparatus 302 base 316
・ Peeling assembly 304 ・ ・ ・ Center post 318 ・ ・
・ Trip cylinder 306 ・ ・ ・ Port 320 ・ ・
・ Trip finger 310 ・ ・ ・ Main lift cylinder 324 ・ ・
· Peeling arm 312 ··· Support arm 326 ···
・ Cushion 314 ・ ・ ・ Center hold

Claims (8)

[Claims] A first substantially transparent disk substrate having a first substantially planar surface and a second surface opposite the first surface, wherein the first substantially transparent disk substrate has a first substantially transparent surface; The surface has a first information layer for storage, a semi-reflective layer is formed on the second surface, and a substantially flat first layer having a reflective layer and a second information layer. 3
Providing a removing layer having a surface of the third surface, disposing the third surface at a position separated by a predetermined distance from the second surface, between the second surface and the third surface Forming a substantially transparent layer on the third surface, the reflecting layer formed on the third surface is moved to the transparent layer to form a fourth surface, and the removing layer is formed of the transparent layer. A method for manufacturing an information recording medium, comprising: 2. The method according to claim 1, further comprising applying a reflective coating to a third surface before the step of arranging the third surface of the shape layer. 3. The method of claim 1, further comprising: after applying the substantially transparent layer between the second surface and the third surface, transferring the reflective layer from the third surface to the second surface. The method for manufacturing an information recording medium according to claim 2, comprising: 4. The method according to claim 1, further comprising applying a reflective layer to the fourth surface after removing the shape layer from the transparent layer. 5. A method, comprising: providing a second substantially transparent disk having a fifth substantially planar surface and a sixth surface opposite said first surface, said sixth surface. Has a third information layer for storing by local change of said sixth surface, applying a semi-reflective layer to said sixth surface, and by applying a local change of said seventh surface. Providing a second removal layer having a substantially planar seventh surface having a fourth information layer for storage at said seventh surface from said sixth surface. Applying a second substantially transparent layer applied between the sixth surface and the seventh surface, disposed at a predetermined distance, the fourth information on the seventh surface A layer being transferred to the transparent material by forming an eighth surface on the second transparent layer; and 2. The method according to claim 1, wherein a leaving layer is removed from the second transparent layer. 6. The method according to claim 1, wherein the first transparent layer is formed on the second transparent layer.
6. The method for manufacturing an information recording medium according to claim 5, comprising bonding to a transparent layer. 7. The method of claim 1, wherein providing the removal layer further comprises providing a peripheral engagement surface on the removal layer. 8. The method of claim 7, wherein removing the removal layer comprises engaging the peripheral engagement surface of the removal layer to separate the removal layer and the transparent layer. the method of.