JPS58137147A - Information recording medium - Google Patents

Abstract

PURPOSE:To make recording performance twice with one disk of two-layered structure, by providing the 1st information recording layer which has high reflectivity to light with the 1st wavelength and low transmittivity to light of the 2nd wavelength, and the 2nd information recording layer which is recordable and readable with the light with the 2nd wavelength. CONSTITUTION:On one surface of a transparent base 13, the 1st information recording layer 11 is formed by a stamper system, etc., by using Sb2 Se3 which has high reflectivity to He-Ne laser light (6,300Angstrom ) and high transmittivity to light with the 2nd wavelength, e.g. semiconductor laser light (8,000Angstrom ). On the layer 11, a layer of a light-transmissive material such as photoresist is provided and then metal (Te, etc.) with a low fusion point is vacuum-deposited to form a recording layer 12 where information is recordable and readable with the light with the 2nd wavelength. One disk having four recording information layers may be formed by stacking said information recording media 10. Thus, doubled recording and reproduction are realized by one disk.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to information recording media, particularly those having a multilayer structure, which are used, for example, in video discs, digital audio discs, and the like.

The track pitch of conventional information recording media of this kind is said to be 1.67μ, which is 1! It is considered impossible to narrow the pitch width because of crosstalk and the diameter of the light beam used for recording and reproducing information on the information recording medium. Therefore, in order to achieve a higher density arrangement than at present, it is inevitable that a multilayer structure will be adopted.

Information recording media with such a multilayer structure have already been proposed, but in this case, as shown in FIG. A reflective surface is formed and the IE
The information recording medium (3) is constructed by overlapping the first and second information recording media (11 and (2)) having a length of N (2 m). The information recording surfaces (11) 1 and 1b (lb) K are read out using a readout light such as a laser beam as shown by the arrows 1 and bK in the information recording medium (31). The device is designed to irradiate a particle and reproduce it using reflected light or interference light.

The present invention is different from such conventional magnetic recording media with a multilayer structure; for example, the two information storage layers can be written and read from the same side of the medium. For example, when adopting a laminated structure of two media as explained in Figure 111, the information storage structure can be substantially equivalent to four or more layers, and the storage density is significantly higher than in the past. Harmonize so that you can improve.

The information recording medium according to the present invention will be described in detail below with reference to the drawings. An example of the information recording medium according to the present invention will be explained with reference to FIG.

In the present invention, at least IIl and the second information register aυ and a2 are stacked, but especially KIII
The informational result 6υ of II is the light 1 of the first wavelength, for example, He
-Ne has a high reflectance for laser light (6300j), and has a second wavelength, such as a semiconductor laser (8ω)
For parties, it is assumed that information records with high transparency are returned.

Information recording and return of lK2 is constructed by a material layer in which distribution (writing) and reading thereof are performed by the above-mentioned second wavelength light, for example, semiconductor laser light.

An example of a manufacturing method for obtaining such an information recording medium Q according to the present invention will be explained with reference to FIGS. 3 to 5. As shown in FIG. 3, an uneven surface (lla
), and KIIE is formed on this surface (l1m) as described above.
A material having a high reflectivity for a wavelength of I, for example, an HC-NC laser beam, and a high transmittance for a wavelength of %I, for example, a semiconductor laser, such as 5b2se3, is deposited to a thickness of, for example, 3001 cm. 1 information stirrup was made 1
111 information records form the aD. Then, as shown in FIG. 4, a polymeric material, such as a light-transmitting material such as photoresist, is formed on this information recording layer αυ by, for example, spinning coating to a thickness of 10 degrees. For example, 1 sol K of a low melting point metal such as Te, which can be melted by semiconductor laser light, is deposited on the upper layer to form 82 information recording layers (13V).
For example, as shown by the middle arrow C in FIG. For example, pits are formed by melting and removing the second information recording material 01) using a semiconductor laser beam depending on the information recording medium.

Furthermore, if the example mentioned above fails! As a result of the information in 1, Mb
28e@, the optical characteristics of this 8b28e3 (wavelength-transmittance C%) characteristics are as shown in Figure 116, and it is clear from this that 5K He-Ne It can be seen that a low transmittance is shown for the laser beam length, and a high transmittance is shown for a wavelength of 500K of semiconductor laser light.

The arrangement of the information recording medium according to the present invention having such a configuration, for example, the arrangement of the information recording layer II2 to the information recording return 13: and the reading of information from υ and a2 of the recording layer to which the information II1 and 112 are distributed are shown in FIG. 87. This can be done by the configuration outlined herein. In the illustrated example, the information recording medium αe is placed on the transfer table (A) and rotated 5. In this case, two lasers emitting laser beams of different wavelengths are provided, for example, a He-Ne laser (21A) and a semiconductor laser (21B). (to) is laser (21A)
and (21B) bias power supply. One laser beam from these lasers (21A) or (21B) is generated by, for example, collimator lens → prism (to) → grating (to) → beam splitter (c) → − plate 4 → tracking construction (2) → Through the objective lens (to) the medium (
I am encouraged to use IOK irradiation. -10,000, the reflected light of the laser beam irradiated onto the medium α is as follows: Objective lens (2) → i-mirror → -*C* → beam splitter (c) → lens system (
2) → The light is sent to the detector O1k, where the optical information is detected and converted into an electrical signal KW. This detection signal is supplied via a demonstrator Gυ to, for example, a television receiver to obtain a reproduction signal, and is adapted to obtain a reproduction signal IIiigI. (To) and (B) are tracking servo circuits and focus servo circuits, each with a mirror (
Tracking and focus are adjusted by referring to the rotation mechanism and the focus adjustment mechanism of the objective lens (b). In addition, a modulator is used to apply a signal modulated by a signal received from a receiver, for example, to a laser (21A) or (21B) IC selected by switching switch 8W1, and emit light from the laser (21A) or (21B) IC. K is designed to control the cabinet s
w2 is an open/close switch, which is opened when writing to the medium ae.

In such a configuration, for example, a switch sw is installed in row 5 for writing to the information recording layer 63 of the medium a.
As shown in the figure, for example, the laser (21B) is switched to a semiconductor laser (21B), and this laser (21B) is operated, and the laser beam #111 is emitted onto the medium. If you k like this, this race 1
The tip passes through the information recording layer riυ of medium α, and
Since the information recording layer 03 of 12 is irradiated, as described above, the recording layer a3 is irradiated with a device using, for example, a melting bit in accordance with the irradiation pattern by scanning the laser beam.

In order to read the information device from the first or second information recording layer Ql and a3, a receiver (to) and a modulator (
), release the open/close switch 3 inserted in
Close w2. In this state, when reading information from the information recording layer III (11), a He-Ne laser (
2] Operate A). When K is set in this manner, this laser beam is reflected by the all information recording layer (llb), so a signal corresponding to the information bit due to the unevenness is detected by the detector (to) and demodulated by the demosier voice 61. Then, a reproduction machine can be obtained by a reproduction machine, for example, a receiver machine. Further, in order to read information from the information recording layer n3 of the device 112, the open/close switch SW3 is opened, the switch sw2 is closed, and the switch 19W is switched in the opposite direction to that shown in the figure to operate the semiconductor laser (21B). In this way, the laser beam passes through the first information recording layer αD and reaches the second information recording layer *7JK, where it is possible to obtain optical information signals such as changes in reflected light due to information bits, interference, etc. This is detected by the detection S (to), demodulated by the demodulator OIK, and a reproducer, such as a receiver, can obtain a reproducer using this information.

Incidentally, in the above-mentioned example, the first information recording layer (Ill
This is a case where the information distribution is formed by the uneven surface formed by stamper molding.
For example, the flat surface K 5b of the base body 0 may be
It is also possible to form a device with 28e3 K and to form a molten bit by laser irradiation. In addition, this recording layer aυ may be formed as a flat layer of 8b2T@1 layer having a prior property, for example, a property of increasing the reflectance for this He-Ne beam by irradiation with a tie-N@laser. can be formed. In the case of e, the placement is done by H, -N, and laser beams, but this placement part is He
-Nll+ll eraser- The semiconductor laser, which has a high reflectance, exhibits high transmittance for both the device section and the non-reflective section.

Additionally, the second recording layer is not limited to the case of using TeK as described above as a low melting point metal, but can also be formed of a similar layer or an alloy layer of Te, B+4, etc. A metal layer or a polymer layer with a relatively low melting point is formed, and M with a relatively high melting point is formed on this layer.
, C, layers, etc. are formed, and the lower low melting point layer is melted by irradiation of light of a second wavelength according to the device information &! By forming sickle bits, it is possible to form distributed pits in the upper refractory metal layer as well. The 112 recording layers a may be made of a material whose optical properties such as refractive index, reflectance, or absorption rate change with light or heat, such as A3*S e * 8 B.
s Te *In, Cd, 8 alone, or alloys thereof, such as Te8e2, 8b28e3, 5
b2Tel, In8e, In2Te3.

1m1Se1. CdTeSe3, Cd8e,
111Te3 including IKTe, such as 8b2TeSe5,
Using Sb2Te3, it is possible to adopt a device mode based on changes in optical properties.

According to the above-described information distribution medium according to the present invention, less than 4
1 has 11 and *2f) Y shell layers 0υ and H agvt, so the amount of information can be increased. There are various ways to use it; for example, one recording layer may be used to store audio signals, and the other recording layer may be used to record video signals. High-definition #I by distributing video signals with both a and a! It can be used in a wide variety of ways, such as making it possible to obtain i1jg/II, or adding additional information to layer 03 of -10,000 on one side.

As described above, the information device medium according to the present invention has, for example, 1[1 and M2 information recording layers, and at least the reading of information from these information recording layers is performed using the same medium. Since it is made from the side, the information recording medium having the structure according to the present invention (
When using IGs by overlapping them as shown in Figure 8,
By using this medium with the front and back reversed according to the system explained in Fig. 7, it is possible to read out the arrangement information of the four layers. This means that the number can be doubled compared to the conventional method described above.

As described above, the information recording medium according to the present invention has the advantage that it is possible to improve the recording density and to diversify its usage.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of an information recording medium with a conventional multilayer structure, and FIG. 2 is an enlarged cross-sectional view of the main parts of an example of an information recording medium according to the present invention. Figures 3 to 5 are process diagrams for explaining one manufacturing method for obtaining an example of the information recording medium according to the present invention, Figure 6 is a transmittance characteristic curve diagram, and Figure 7 is a diagram showing the information recording medium according to the present invention. FIG. 8 is an enlarged sectional view of a main part of another example of the information storage medium according to the present invention. Oe is the information distribution medium according to the present invention, (11) and Ozui
IEI and second information 1 碌1, respectively. Figure 6

Claims (1)

[Claims] It has a third information storage layer and a second information storage layer, and the third information storage layer has a high reflectance for light of a first wavelength and a high reflectance for light of a second wavelength. has high transmittance,
The second information storage layer is an information storage medium made of a material tatami on which information is arranged and read by light of wavelength @2.