KR830000647B1 - Optical recording disc - Google Patents

Abstract

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Description

Optical recording disc

1 is a cross sectional view of a recording disc according to the present invention;

2 is a cross-sectional view of another embodiment of an information disc.

3 is a cross-sectional view of another embodiment of an information disc.

4 is a photograph of a portion of the surface of an information disc shown in FIG. 3 with information.

5 is an enlarged photograph of the photograph shown in FIG.

6 is a cross-sectional view of another embodiment of an information disc according to the present invention.

The present invention provides optical recording and decryption of information on a disc-like substrate having an amorphous recording layer on at least one surface where the exposed portion is dissolved to form holes (information bits) when exposed to high energy light modulated according to the information. It relates to a possible optical recording disc.

Such discs are described in Dutch Patent Application No. 7607997. Discs described in the patent specification always include a substrate whose recording layer comprises at least 30 atomic% Se and or Te. By exposure to modulated laser light, a dissolution region is formed, which is constricted to form a hole because the material produced here forms a red wall.

It is an object of the present invention to increase the sensitivity of information recording, whereby materials which previously had no sensitivity or materials in which the information bits can be provided with large, high laser light energy, for example mixture-like amorphous materials, can be readily used. This implies that information bits (holes) can be formed in this material as an appropriate amount of laser light.

It is another object of the present invention to provide an optical recording disc in which very small holes can be formed with a small amount of laser light. Here a relatively increased information density is obtained.

It is another object of the present invention to provide an optical information disc in which small holes of different diameters can be formed by some laser light energy. This allows for analog recording of information with greater information density.

It is based on the fact that relatively much energy of the present invention is required to start making holes in the amorphous recording layer. This relatively large energy barrier cannot be overcome by only thermal promotion of the melting zone.

In Applicant's non-disclosed patent application No. 7902542 (PHN 9407), the calculations are recorded with respect to the minimum hole diameter associated with the required activation energy. According to the Dutch application, the Marangoni effect, which represents an unstabilization treatment in a liquid film where the mass transition occurs in the thin film portion with the largest surface energy as a result of the change in surface energy, makes a significant contribution to the energy required for hole generation. Described. According to the Dutch patent application, the measurement is presented to optimize the marangoni effect.

It can be seen from the above application that external instability, i.e., instability outside the recording layer where holes are formed, greatly promotes hole construction. In the case of using a known recording disc, it has been found experimentally that a solution region given in an amorphous recording layer by laser light has a relatively large diameter before the solution in the region contracts to form a hole having a raised portion. Given the external instability, a hole with a smaller diameter of the melting area obtained on the recording layer by exposure to laser light is already formed. This means that smaller laser light energy is sufficient to get smaller holes. This also means that amorphous recording materials having a very low strength so far have also become useful.

The present invention relates in particular to an optical recording disc, characterized in that the substrate is externally unstable on the recording layer surface.

For example, a hole having a diameter of about 0.3 μm by laser light may be given to an amorphous recording layer of a Te alloy, eg, a Ge / Te alloy having a thickness of 30 to 40 nm. The amount of laser light energy per hole (information bit) is 0.4nJ and is generated from a laser with a wavelength of 647nm and a pulse time of 75µS on a recording layer with 5mW of power. When using the same laser having a pulse time of 100 s, a melting area is obtained in the recording layer having relatively large diameter holes having a diameter of about 1.0 m. The laser energy usage yields holes of various diameters, for example, grooves with a diameter of 1.5 μm at maximum. In addition to binary information recording, the present invention allows analog information recording with greater information density, such as ternary recording (large groove, small groove, no groove). For example, 8 bits are required for binary recording of 200 characters (2 ⁷ <200 <2 ⁸ ) and 5 bits are required for ternary recording (3 ⁴ <200 < ³⁵ ).

This external adhesion stability may be a chemical deposit on the surface of the substrate adjacent to the recording layer. For example, it may be an atom dispersed on the surface of the substrate.

In a preferred embodiment of the optical recording disc according to the present invention, the surface of the substrate proximate to the recording layer has a discontinuous surface at a position where grooves are formed in the exposed overlying recording layer.

In this embodiment, the external instability has mechanical properties. In discontinuous regions, the surface shows a level step as a result of local grooves or protrusions on the surface. As described above, the strong effect of the adherent surface in the groove construction in which the dissolution region in the recording layer opens more quickly to a very small diameter can hardly be explained. This phenomenon found is explained in part by the internal solution pressure in the melting zone by laser light. In discontinuous regions, the surface represents a ridge with reduced radius of curvature compared to the flat surface. Inward solution pressure is inversely proportional to the radius of curvature and is steadily increased in the area of continuity.

It is very important that the bend radius of the substrate surface is as small as possible at the discontinuous position so that the angle that the above-mentioned edges make with the substrate is as sharp as possible.

In another embodiment of a recording disc with good results, the discontinuous surface has a zigzag diameter dimension of 30 nm to 300 nm and a recording layer 30 to 40 nm thick.

The word diameter dimension includes, for example, the width dimension of the scratch provided in the substrate surface.

In the embodiment of the disc according to the present invention, a substrate of synthetic resin or glass is used, and the surface of the substrate can be chemically or mechanically roughened or scraped from the surface adjacent to the recording layer, and the surface close to the recording layer is a discrete surface. A copy of the surface of the containing matrix.

Chemical roughness can be obtained by polishing the substrate surface by etching. For example, a substrate made from polymethy1 methacrylate can be obtained because the roughness is treated with perxhloric acid for 5-10 seconds in particular.

Mechanical roughness can be performed by known methods. That is, for example, the substrate surface consists of the use of a device ground by sand paper, ie sand paper.

Suitable are substrates having a surface that is a radiation of the matrix surface including discontinuities. In the manufacturing process of the recording disc, the process of roughening individually becomes unnecessary because each substrate disk does not need to be processed. Suitable substrate disks can be manufactured according to conventional techniques by a matrix comprising in the surface the discontinuous negatives required within the substrate surface. Suitable techniques are, for example, the mass of a plastic resin, for example PVC, located centrally on the bottom matrix, at elevated temperatures and with desirable discontinuities. It is a crimping technique for crimping onto a substrate disk by its apparatus. Instead of a die, low metrics can be provided to have surface discontinuities. The matrices also have discrete surfaces. Another technique is injection molding technique. In other words, a liquid composition of plastic synthetic resin, for example polymethylmethacrylate, is pressed into a cavity of a bowl having one or two matrices with surface discontinuities.

These metrics can usually be made of metals such as nickel and cannot provide the desired surface discontinuity by the chemical or mechanical treatment described above. The matrix plate, which is also a glass plate with a photo lacquer of the desired structure, is coated by an electroless method and then electroplated with metal, after which the growth metal thin film is removed from the circular plate. In this method, the roughness of the photographic lacquer surface can be obtained by the selection of the photographic lacquer developer.

In another embodiment, the substrate on one surface of the recording layer includes a coating layer that becomes a discontinuous surface. During termination, the so-called insular stage arrives at the first bond where the deposition material is deposited on the substrate to be coated as island regions distributed over the substrate surface identity. It can be used directly as a deposition layer in the island region. For example, the deposition layer of Au in an island region is mentioned.

Another suitable coating layer is a coarse grained deposition layer of the material. A typical example is a layer of deposited vanadilpotocyanine. Here the temperature of the substrate to be coated is maintained at least 60 to 80 ° C. during deposition. As a result, a rough granular layer of vanadil portalocyanine which can be used as a coating layer can be obtained.

In a suitable form of the disc according to the present invention, the coating layer is a surface which is a radiation of the surface of the matrix including a discontinuous surface or a light absorbing layer of a rough lacquer roughly scratched chemically or mechanically.

For example, the light absorption lacquer layer is an ultraviolet light absorption lacquer layer based on acrylic acid ester. It is desirable to provide a layer of lacquer on the substrate by a matrix device having a preferred discontinuous surface. For this purpose a liquid, light absorbing lacquer layer is provided on the discontinuous mechilix surface and then the substrate is placed on the lacquer layer. This lacquer layer is exposed to ultraviolet light through the substrate or matrix so that the substrate and light absorbing layer are connected to it and removed from the matrix after the structure of the matrix surface is radiated. Finally, the lacquer layer serves as an amorphous recording layer, which is a termination layer of Te-Ge of 30 to 40 nm. By being exposed through the substrate or matrix, the substrate and matrix must be transparent in the ultraviolet light used. Suitable are the use of transparent substrates made from glass or transparent synthetic resins such as polymethylmethacrylate, polysulfone, polycarbonite or PVC.

In still another embodiment of the present invention, the substrate on one side of the recording layer has an optically decodable drive track which partially has an exchange structure of the antagonist drive area alternately at a high or low level.

Typical drive tracks consist of spirals or concentric circles and drive zones alternately located at high and low levels give the track a serrated contour. The longitudinal lengths of the drive areas, showing the shape of the block and the hole, change to fit the driven data and are roughened from 0.3 to 3 μm. The height difference between the blocks and the holes is about 0.1 μm.

The apparatus according to the invention having a drive track has the advantage that the information recording in the recording layer is precisely controlled by the drive data in the drive track which contains the information according to the position of the recording and the speed of the information recording. The laser light beam, which scans the drive track through a transparent substrate which will be referred to later as drive laser light, transfers the drive data to a control device that switches the laser light at a relatively high energy at which desirable information can be recorded in the recording layer.

The recording of information takes place in the portion of the recording layer located on the drive track between the drive data.

Such a drive track is provided in the engine by a device of the matrix provided as a drive track according to known and described methods, for example, a molding method or an injection molding process. It is inferred that a matrix is used that additionally has a desired discontinuous surface in the drive track. However, the substrate comprising the drive track may be provided differently from the coating layer comprising a discontinuous surface, such as a coarse adhesion layer of vanadil phthalocyanine or a termination layer of Au in the middle stage, or provided with scratches. This is necessary because it can be mechanically or chemically roughened by post-treatment on the side of the drive track. However, the method described below is a secondary processing step.

In an embodiment, a drive track is provided in the light absorption lacquer layer that resides on the substrate and includes a discontinuous surface. The recording disc according to the embodiment described below removes the lacquer layer of the light absorbing lacquer on the surface of the matrix including the discontinuous surface and the drive track, then provides a transparent substrate, and exposes the lacquer layer through the substrate to ultraviolet light. And an absorbing lacquer layer each substrate in which drive tracks and discontinuous surfaces are connected to radiation from the matrix surface, and is prepared by providing an absorbing lacquer layer having a recording layer.

A matrix with a drive track may be tracked in another continuous dielectric print, such as a mother plate, a child plate, and a growth metal peel (subplate) after the metrics have been manufactured. By this exposed exposure and development, a drive track is produced by providing in the photographic lacquer layer of the master plate. Prior to providing a discontinuous surface, the matrix with the drive track may be roughened or have mechanical or chemical scratches or may be, for example, a rough adhesion layer of vanadilpetarosinin or a layered layer angle such as 30 nm thick. It is covered as a coating layer containing discontinuities.

For example, the recording layer used in the recording disc according to the present invention is a rapid recording layer or a brass glass layer which can be provided by a termination treatment having a thickness of about 30 to 40 nm. A very suitable recording layer is an amorphous layer of a composite of Te with one or more components selected from As, Sb, Ge, Sn, Si, Ga, ln, TI, Se, and S. The Te containing recording layers used directly are described in Applicant's Dutch Patent Application No. 752543 (PHN 9406).

The engine used in the recording disc according to the present invention is transparent and made from the above-mentioned transparent synthetic resin or glass. In such a disc, information can be recorded or read out by the device of the laser light through the substrate, so that a structure such as particulates is first present on the surface of the disc that is at a depth of focus for the purpose of focusing the laser light on the recording layer. .

Hereinafter, the present invention will be described in more detail with reference to the drawings.

Reference numeral 1 in FIG. 1 denotes a micrometer-thick engine of polymethylmethacrylate with mechanically roughened side surfaces. The resulting shape of the scratch is shown as 2 in the figure. These scratches have a depth of 20 nm with a width of 50 nm. The surface having such a discontinuous surface has a terminal recording layer 3 of Te, Se, Sb having a thickness of 30 nm. The surface of the recording layer 3 away from the substrate has a form 4 of scratches corresponding to the form 2 of the scratch. In relation to this, the shape of the engine surface is achieved by terminating the recording layer.

The optical shown in Figure 1 when recording information

The recording disc is exposed through the substrate 1 to pulsed laser light applied from a laser having a pulse time of 500 ns, a radiation plate of 800 nm and a power of 2.3 mW on the recording layer. As a result of exposure for 500 ns, a hole 5 is formed in the recording layer 3. This hole has a diameter of 0.2 탆 and includes a recording material 6 which includes a ridge portion 6 and hardens out of the hole in liquid form to form the ridge portion 6.

In Fig. 2, the reference numeral 7 denotes a plate of polymethyl methacrylate having a thickness of 1 mm, and the deposited layer 8 of vanadil phthalocyanide showing a coarse adhesion structure 9 having a surface apart from the plate 7. ) On one side. The detailed structure of the rough attachment surface has a diameter dimension of about 70 to 100 mm. This rough adhesion layer is usually constituted by a terminal vanadil petalocyanide at temperature (room temperature) and by maintaining the deposition layer at a temperature of 80 ° C. for several hours. It is also possible to maintain the substrate at a temperature of 80 ° C. during the termination of vanadil petalocyanide. The deposition coating layer 8 has a thickness of 26.5 nm and includes a deposition recording layer 10 of Te ₁ , Sb ₁ , Se at a thickness of 30 nm. The recording layer also has a rough attachment structure 11 corresponding to the layer 8.

The information layer, the recording layer 10, is exposed to pulsed laser light applied from a laser having a pulse time of 1 s, a radiation plate of 647 nm and a power of 3 mW on the recording layer. Exposed. A hole 12 is formed in the recording layer by exposure of 1 mu s and surrounded by the container portion 13 of the recording material coming out of the hole. The diameter of this hole is 0.75 μm. If the recording layer of Te ₁ , Se ₁ , Sb ₁ , provided directly on the plate 7 has no coating layer 8 showing no coarse adhesion structure, the minimum hole dimension is at least 1.3 μm.

Reference numeral 14 in FIG. 3 denotes a 1 mm thick substrate of polymetal methacrylate provided on one side with an ultraviolet light absorbing lacquer layer 15 provided with a drive track 16. The lacquer layer 15 provides a matrix surface comprising a drive track having a layer of liquid and light absorbing lacquer based on acrylic acid, which is then plated with a glass plate, and then the UV light through the substrate to the lacquer layer. After absorbing, a drive track is provided by removing the assembly of absorbed lacquer layered glass plates on which matrix surfaces are formed. The drive track is 0.6 μm wide and 0.2 μm deep. The lacquer layer 15 has a coarse adhesion layer of vanadil phthalocyanine 17 in a 66 nm thickness obtained by terminating vanadil petalocyanine at room temperature and holding this layer at 80 ° C. for 10 hours. In other words, the layer 17 has a recording layer 18 of Ge ₁₅ Te _{85 having} a thickness of 30 nm. The surface of layer 18 exhibits a structure consistent with layer 17.

In the inverse of the drive track 19 when recording information, the recording layer 18 is pulsed laser light applied from a laser having a pulse time of 500 ns, an emission plate length of 800 nm, and a power of 2 mW on the recording layer through the substrate 14. Is exposed to. As a result of the 500 ns exposure, a hole 20 is formed in the recording layer 18 with a diameter of 1.0 mu m, and is surrounded by the container portion 20 of the recording material coming out of the hole 20. If the rough adsorption layer 17 of vanadil penalocyanine is not used and the recording layer 18 does not have a rough surface shape, the holes are formed in the recording layer with only 4.6 mW of laser light power and a pulse time of 500 ns. These holes will have a diameter of 1.5 μm.

4 is a partial photograph of the surface of the recording layer shown in FIG. Various drive tracks and holes (information bits) provided in the recording layer in the area of the drive track and having ridges are made very visible. It is also possible to see the rough adhesion surface formation of the recording layer. The dotted line at the bottom of the picture is the measurement line, and each part of this line is 1 μm long.

FIG. 5 is an enlarged photograph of FIG. 4, where the rough adhesion surface of the recording layer can be clearly seen.

In FIG. 6, reference numeral 12 shows a 1 mm thick substrate of polymetal methacrylate given a UV light fixed lacquer layer 23 having a drive track 24 and a rough surface 25 on one side. The lacquer layer 23 having the drive track 24 and the rough surface 25 provides a light absorption lacquer phase based on, for example, acrylate ester, on the rough matrix surface comprising the drive track and the substrate Is then obtained by absorbing ultraviolet light through the substrate and removing the resulting assembly of the absorbing lacquer layer and the substrate from which the drive track and the surface morphology of the matrix are radiated.

Matrixes with drive tracks and rough surfaces, for example, smooth surfaces and drive tracks. Nickel matrixes, for example, smooth surfaces and drive tracks, have a layer of vanadil phthalocyanine on the Nickel matrix. It can be prepared so as to terminate at.

The rocker layer 23 has a deposition recording layer 26 of In ₅₀ Bi _{50 that} is a 30 nm thick layer. The recording layer 26 has a surface structure 27 that matches the structure of the layer 23.

When recording information, the recording layer 26 is exposed through the substrate 22 to the pulsed laser light having a power of 2.5 mW, a radiation plate length of 676 nm and a pulse time of 100 ns on the recording layer. As a result of the exposure of 100 ns, a hole 28 is formed in the recording layer 26 with a diameter of 0.2 탆 and has a container portion 29. Using a laser light output of 8.5 mW and a pulse time of 100 ns, a hole with a diameter of 0.75 μm is obtained, allowing analog information recording.

Claims (1)

When one side is exposed to high energy light modulated according to the information, the disk-like substrate is an amorphous recording layer (3, 10, 18, 26) in which the exposed portion is dissolved to form the holes (5, 12, 20, 28). 1, 7, 12, 14, wherein the optical recording disc is optically recorded and decoded, wherein the substrate surface in contact with the recording layer has at least the discontinuous surface 2 where holes are formed in the upper recording layer upon exposure. An optical recording disc, comprising: a coating layer (8, 17, 23) having a substrate on the recording layer side or having a discontinuous surface (9, 25).

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