JPH04285737A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To improve the peeling strength of the layer adjacent to a recording layer by roughening the uppermost surface of the recording medium. CONSTITUTION:The recording layer 2, a reflection layer 3 and a protective layer 4 are successively formed on a substrate 1. The protective layer 4 is formed of a UV curing resin, etc., and its surface is roughened by uniformly sticking alumina powder having 1 to 50mum grain size thereto. A transparent substrate consisting of a polycarbonate resin, glass, etc., is used for the substrate 1. The layer 2 consists of the org. dye film, for which a phthalocyanine org. dye is preferably used. The layer 3 consists of thin metallic films of Au, Al, etc.

Description

Description: FIELD OF INDUSTRIAL APPLICATION The present invention relates to an optical information recording medium. More specifically, the present invention provides a recording film including an organic layer;
The present invention relates to a novel configuration of an optical information recording medium including a reflective film formed adjacent to a recording layer. BACKGROUND OF THE INVENTION [0002] In recent years, the establishment of a storage technology for the rapidly increasing amount of information to be processed has become an urgent and unavoidable issue. Various optical recording media that utilize laser light are attracting attention as the most suitable for solving these problems. In other words, optical recording media generally allow high-density information recording, and unlike conventional magnetic recording media, the recorded information is resistant to electromagnetic interference, and there are also methods that allow for mass duplication. It has excellent characteristics. [0003] Optical recording media have various usage formats such as write-once type and rewritable type, shapes such as disks, drums, and cards, and various recording methods such as perforated type, magneto-optical type, and phase change type. A wide variety of combinations have been developed, and some have already been put into practical use. One of the most basic optical information recording media is the so-called write-once type. A write-once optical recording medium records information by causing an irreversible change in the characteristics of the recording film, that is, a change in the shape, form, or optical characteristics of the recording film, by irradiation with laser light. This type of optical information recording medium has already been put into practical use as a recording medium for still image filing systems, etc., and the recording film is made of low melting point metals such as Te and Bi, their alloys, compounds, or dispersions. It is being On the other hand, as playback-only optical information recording media, compact discs (CDs) that record digital signals for audio and laser discs (LDs) that record analog signals for video signals have become extremely widespread. There is. Inexpensive and high-performance playback devices for these optical discs are already in widespread use. [0006] Therefore, an attempt has been made to utilize this widely popular CD player as a read-out device for write-once optical discs. This method eliminates the need for large equipment such as master disk manufacturing equipment, substrate molding equipment, and reflective film deposition equipment for making CDs, making it possible to manufacture CDs in relatively small quantities at low cost. Furthermore, it becomes possible for the user to produce a CDROM that records a large amount of information. Furthermore, when considered as a reading device for optical recording media, CD players are extremely inexpensive, and it is thought that the spread of optical recording media will be rapidly promoted. [0007] However, the optical recording medium used in this method must have characteristics that allow writing with a write-once optical recording medium writing device and playback with a CD player. That is, high recording sensitivity that can be irreversibly changed with a writing device for write-once optical recording media;
It must also have high reflective properties that can be played on a CD player. [0008] Problems to be Solved by the Invention [0008] As a write-once optical recording medium that is required to have the above-mentioned special characteristics, a high-reflectance material such as Au or Al is used adjacent to the recording film. It has been proposed that a metal reflective film is provided to improve reflection characteristics. Furthermore, the use of an organic dye film has been proposed as a recording film with high recording sensitivity. However, the organic dye used here as a material for the recording layer has low adhesion strength to the material directly above or below it, and in a peel test using adhesive tape, it was found that it did not adhere well to other optical information recording media. Shows significantly poor performance. Therefore, the present invention solves the above-mentioned problems of the prior art, and provides a novel optical information recording system that uses an organic dye as a material for the recording layer while effectively preventing peeling in the recording layer. Its purpose is to provide a medium. [Means for Solving the Problems] That is, according to the present invention, a substrate, a recording layer made of an organic film formed on the substrate, and a protective layer formed at least above the recording layer. An optical information recording medium is provided, characterized in that the surface of the uppermost layer of the optical information recording medium is a rough surface having a surface roughness RMAX of 1 μm or more. [0012] The optical information recording medium according to the present invention is characterized in that its surface layer is constructed to have a rough surface. That is, in the conventional optical information recording medium, the uppermost layer was a rigid protective layer mainly intended for protection against physical scratches and the like. This type of protective layer is generally formed of an ultraviolet curable resin or the like, and when a sticky substance is attached and a tensile force is applied, peeling occurs in the relatively weak recording layer. On the other hand, since the optical information recording medium according to the present invention has a rough surface, even if the adhesive comes into contact with it, the area to which the adhesive actually adheres is small. Therefore, the adhesion strength of the adhesive does not become so high as to cause the recording layer to peel off. In order for the surface of the optical information recording medium according to the present invention to effectively fulfill the above-mentioned functions, it is preferable that the surface roughness RMAX is 1 μm or more. In order to achieve such a surface roughness RMAX, it can be formed by dispersing or mixing powder into the material of the protective layer, which is the surface layer of the optical information recording medium. There is also a method of transferring a rough three-dimensional pattern to the protective layer forming the surface layer by physical processing such as the 2P method or roll coating. [0018] The present invention will now be described in more detail with reference to Examples, but the following disclosure is merely an example of the present invention and is not intended to limit the technical scope of the present invention in any way. Embodiment FIG. 1 is a diagram showing a specific example of the structure of an optical information recording medium according to the present invention. As shown in the figure, this optical information recording medium is composed of a substrate 1, and a recording layer 2, a reflective layer 3, and a protective layer 4, which are successively laminated on the substrate 1. [0021] Here, the substrate 1 can be any transparent substrate commonly used in optical information recording media, and specifically, polycarbonate resin, polymethyl methacrylate resin, epoxy resin, amorphous polyolefin resin. , glass, etc. The recording layer 2 is formed of an organic dye film, and phthalocyanine organic dyes are particularly preferred from the viewpoint of light resistance. This type of organic dye film can be formed into a uniform film by spin coating. Furthermore, the reflective layer 3 can be formed of a metal thin film such as Au or Al, and preferably has a reflectance of 50% or more, provided that it can be played back on a CD player. Note that the reflective layer 3 can be formed by a physical thin film forming method such as a vacuum evaporation method, a sputtering method, or an ion plating method. Furthermore, the protective layer 4 can be formed of an ultraviolet curing resin or the like, and a spin coating method is generally used as a forming method. Note that, as will be specifically described later, the surface of this protective layer 4 has a roughness equal to or higher than surface roughness RMAX. Although not shown in the drawings, in reality, a label or other display is printed on the protective layer 4 by offset printing, screen printing, or the like to form a product. [Production Example 1] Diameter: 120 mm, thickness: 1
．． An optical information recording medium according to the present invention was manufactured using a polycarbonate resin substrate with a 2 mm spiral groove. As a recording layer, a phthalocyanine organic dye film having a thickness of 130 nm was formed by spin coating. Next, a reflective layer made of a thin Au film having a thickness of 80 nm was formed on this recording layer by direct current sputtering. [0028] Subsequently, as a protective layer, a layer of ultraviolet curable resin (SD-17, manufactured by Dainippon Ink) with a thickness of 5 μm was applied by spin coating, and alumina powder with a particle size of 1 to 50 μm was uniformly adhered. It was then cured by ultraviolet irradiation. Cellophane tape (trade name/manufactured by Sekisui Kagaku Co., Ltd./adhesive tape JIS Z 1522) with a width of 15 mm was pasted over a length of 40 mm to the optical information recording medium produced as described above. A peel test was performed five times. Further, after being left in a high-temperature, high-humidity tank at 80° C. and 85% RH for 1000 hours, a peel test was conducted five times under the same conditions. The test results are shown in Table 1 together with the test results of other production examples and comparative examples. [Comparative Example 1] An optical information recording medium was manufactured using the same materials and conditions as in Manufacturing Example 1. However, no alumina powder was attached to the protective layer, and the ultraviolet curable resin was cured as it was. The optical information recording medium thus produced was subjected to a peel test under the same conditions as the production example and other comparative examples. The test results are also shown in Table 1. [Production Example 2] Diameter: 120 mm, thickness: 1
．． An optical information recording medium according to the present invention was manufactured using a polycarbonate resin substrate with a 2 mm spiral groove. The recording layer was formed with a thickness of 140n by spin coating.
A cyanine-based organic dye film of m was formed. Next, a 90 nm thick Au film was deposited on the recording layer by direct current sputtering.
A reflective layer made of a thin film was formed. [0033] Next, using a stamper with a concavo-convex pattern formed on its surface, a 10 μm thick layer of ultraviolet curable resin (SD-17 manufactured by Dainippon Ink) was applied by the 2P method and cured by ultraviolet irradiation. It was used as a protective layer. Furthermore, a label was offset printed on the protective layer using Toyo Ink Co., Ltd.'s ink (FD Aquares) to complete the optical information recording medium. A peel test was conducted under the same conditions as in the production example and comparative example. The test results are also shown in Table 1. [Comparative example 2] An optical information recording medium was produced using the same materials and conditions as in production example 2. However, the protective layer was formed by a spin coating method so that the surface remained smooth.The optical information recording medium thus prepared was peeled under the same conditions as the preparation example and other comparative examples. A test was conducted. The test results are also shown in Table 1. [Table 1] [Effects of the Invention] As explained above, the optical information recording medium according to the present invention has a rough surface. Since it is a flat surface, it has the same function as having high peel strength against adhesive materials, even though an organic material is used as the recording layer material.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a specific example of the configuration of an optical information recording medium according to the present invention.

[Explanation of symbols]

1. Substrate, 2 Recording layer, 3. Reflective layer, 4 Protective layer

Claims (6)

[Claims] 1. An optical information recording medium comprising a substrate, a recording layer made of an organic film formed on the substrate, and a protective layer formed at least above the recording layer. The surface of the top layer has a surface roughness RMAX of 1μ
An optical information recording medium characterized by having a rough surface of m or more. 2. The optical information recording medium according to claim 1, wherein the rough surface is formed of an organic resin in which powder is dispersed or adhered. 3. The optical information recording medium according to claim 2, wherein the organic resin layer forming the rough surface is formed of resin by a spin coating method. 4. The optical information recording medium according to claim 1, wherein the rough surface is formed of an organic resin onto which a three-dimensional pattern has been transferred using a 2P method. 5. The optical information recording medium according to claim 1, wherein the organic resin forming the rough surface is made of an ultraviolet curable resin. Optical information recording medium. 6. The optical information recording medium according to claim 1, wherein the substrate is a transparent plastic made of polycarbonate resin, polymethyl methacrylate resin, epoxy resin, or amorphous polyolefin resin. An optical information recording medium characterized by being a substrate.