JPS61194656A - Information recording medium - Google Patents

Abstract

PURPOSE:To obtain an information recording medium which does not require an automatic focusing system by forming a recording medium of a metal or alloy which has at least two kinds of crystal structure in a solid state, maintains the crystal structure of one temp. region in the other temp. region and/or induces the volumetric changes different from each other in a crystal state. CONSTITUTION:An objective lens which condenses the light from a light source and forms a spot is united to the recording medium. The recording medium is formed of the metal or alloy which has at least two kinds of the crystal structure in the solid state, maintains the crystal structure of one temp. region in the other temp. region and/or induces the volumeric changes different from each other in the crystal state. The optical disk which does not require automatic focusing is thus constituted. The high density and high speed recording and reproducing are possible even if the rotating speed of the disk is decreased by scanning the disk with a beam in the radial direction thereof by using a galvanomirror.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention includes an optical V-lens device suitable for use in an optical system requiring focus adjustment such as an optical disk device, a camera, and a V-zer beam printer. Regarding information recording media.

[Background of the invention]

The above-mentioned device is an optical system composed of many lenses, and the lenses are mainly composed of glass.

In addition, many of the lenses have a lens drive mechanism in order to automatically adjust the focus.

As a typical example of such an optical system, an optical disk device is known from the magazine [Hitachi Hyoron J, August 1984 issue, etc.].

[Purpose of the invention]

An object of the present invention is to provide an information recording medium that does not require an automatic focusing system.

[Summary of the invention]

The present invention integrates an objective lens and an optical disk, has at least two types of crystal structures in a solid state as the recording medium, maintains the crystal structure in one temperature range in the other temperature range, and An information recording medium characterized in that it is made of a metal or an alloy that causes different t volume changes in a crystalline state.

Note that any alloy that causes a change in unevenness can be used even if no crystal change occurs.

Examples of alloys include Cu-A1 alloy, Cu-Zn alloy, C
u-7Vl-Zn alloy, Cu-At-Ni alloy, Cu-
At-Mn alloy, Cu-At-Fe-Cr alloy, Cu-
Qa gold alloy + Cu At Qa alloy, Cu-In alloy,
CbbAA-In alloy.

(: u-Ga alloy, Cu-ht-Ge alloy, Cu-8u
alloy, Cu-'I''e alloy, Cu-Ti alloy.

Cu-At-8a alloy, Cu-Zn alloy, Cu-5i alloy, cu-sb gold alloy Cu-Be alloy.

Cu-[3a alloy, CLI-Mn alloy, Cu-pd gold alloy, cu-pt gold alloy, Ag-Zn alloy, Ag-A/.

Alloy, Ag-Cd alloy, xg-In alloy, Ag-Qa alloy, Ag-AL-Au alloy, xg-AL-Cu alloy, A
g-At-Au-Cu alloy, Ag-ht-Cd alloy, Δ
g-pt metal alloy, xg-8 alloy.

xg-8n alloy, Ag-'pe alloy lAg-Ti alloy,
Ag-Zr alloy, Ag-As alloy, Ag-Au alloy, A
g-Be alloy, Ag-Mg alloy.

Ag-Li alloy, Ag-Mn alloy, At-Fe alloy, A
t-Mg alloy, xt-Mn alloy, At-pd gold alloy AL
-Te alloy, At-Ti alloy.

AA-Zn alloy, At-Zr gold alloy + N I S b
Alloy, Ni-8n alloy, Ni-8n alloy, N1-()a
alloy, Mn-Ge alloy, Ni-Ge alloy.

Nf-Mn alloy, Ni-8 alloy, Ni-Ti alloy.

Fe-As alloy, As-8 alloy, As-Zn alloy.

Fe-13a alloy, l'e-Ni alloy, Fe-Cr alloy, Fe-P alloy, Mn-Pd alloy, Mn-Pt alloy, M
n-8b alloy, Mn-8i alloy, Au-Ca alloy, Au
-A1 alloy, Au-In alloy.

Au-Ga alloy, 4u-Ca alloy, 4u-Cu alloy,
Au-1; 'e gold alloy, Au-Mn gold alloy, p, u-Zn alloy, 3a-Ca alloy, B1-Pb alloy.

Bi-Tt alloy, Ti-Ni alloy, N1-V alloy.

Ni-Zn alloy, Cd-Li alloy, Cd-Mg alloy, C
d-Pb alloy, Cd-8b alloy, 5b-In alloy, 5b
-In-Be alloy, Mg-Ce alloy, Co-Cr alloy,
Co-Ge alloy, CoMn alloy, Co-8b alloy, Co
-V alloy, In-Mg alloy, In-Mn alloy, In-
Ni alloy, In-8n alloy, In-Tt alloy, Li-Z
n-alloy.

Mn-Zn alloy, Pb-T/1. alloy, pb-s alloy.

pb-sb gold alloy Pd-Zn alloy, 5n-8b alloy, T
t-8b alloy, 5b-Zn alloy, Ti-8u alloy, Tt
-an alloy, Zr-8n alloy.

7, r-'l'h alloy, Ti-Zn alloy, gold alloy, i-Zr alloy, etc.

As examples of alloys, the following are preferred in terms of weight composition.

30-46% Zn, 6-10% AA in Ag.

40-60% Cd, 20-30% In alone, 1 in Cu
0~20%8tI 2~30%G3゜20~40%I
n, 20~30XGe, 1.5~35%
8n, 10-60% Zn, 5-109 (St.

4-15% Be, 30-45% Sb alone, 15% in Au
~25%In, 10~15%Ga, 5~25%Zn, 2
0~55%Cd, Z5~5%At alone, 55~5%Ni
Alloy containing 60% At and 40-50% Ti, I
n-25-35% Tt alloy, alloy with 55% or less of PT added to Fe.

M n -5~50% Cu alloy, 5e15~25%-I
n30-40%-Sb alloy. The following elements other than the second component can be added as a third component to these alloys.

Ia, [a, va, Vat　■a+■a,■.

Ib-Vb, the total of one or more rare earth elements is 1
It is 5% by weight or less.

Specifically, the Ia group is Li, and the Ira group is Mg.

Ca, va group is T r , Z r , Hf ,
The Y a family is ■.

Nb, 'l'a, va group is Cr, Mo, W, ■a group is M n, ■ group is Co, l(, h, I r, Fe, R
u.

Os, Ni, Pd, Pt, Ib group is Cu, Ag.

Au, Ib group is Zn, Cd, mb group is B, AL.

Ga, InN tvb group is C, Si, Qe, Sn.

The Pb and Vb groups are P, Sb, and Bi, and the rare earth element X is Y.

La, Ce, Sm, Gd, Tb, D)', and Lu are preferred. In particular, 0.1 to 5% by weight is preferred.

It is also possible to use an alloy in which the irregularities are formed by melting and sublimating an alloy mainly composed of cylindrical, 'l'e, and Se.

[Embodiments of the invention]

FIG. 9 shows the overall configuration of the optical system of the optical disk device. The symbols of each part in the figure and their operations will be explained below. 1
is the V-the diode that serves as the light source. A collimation lens 2 converts the light beam from the laser diode 1 into parallel light. The collimation lens 3 is composed of two parallel semicylindrical lenses. Reference numeral 3 denotes a polarizing beam splitter (hereinafter abbreviated as PBS), which transmits the output light of the collimation lens and refracts the light taken from the λ/4 plate indicated by symbol 4, which will be described below. λ/4 plate is PB
In S3, it is used for phase polarization of light to facilitate discrimination between incident light and reflected light. Reference numeral 5 denotes an objective lens, which is used to condense incident light.

A coupling lens 6 receives the light flux from the PBS 3 and condenses it. The coupling lens 6 is composed of two semicylindrical lenses that are orthogonal to each other. 7 is a photodetector. The photodetector 7 indirectly detects the shape of the light spot of the output light L5 from the objective lens 5 by detecting the shape of the light spot of the incident light L6 from the coupling lens 6. 8 is an actuator, and the actuator 8 adjusts the focal position of the output light L5 of the objective lens 5 according to the output of the photodetector 7. Reference numeral 85 denotes a lens drive section, and the lens drive section 81 adjusts the position of the objective lens 5 based on the drive control output from the actuator 8. 9 is a disk on which information can be optically recorded, reproduced, erased, etc., and a portion thereof is shown.

The disk 9 enables the above-mentioned recording, reproduction, erasing, etc. by irradiating a desired light spot on the disk surface with the output light L5 from the objective lens 5. 86 is a motor, and the disk 9 is driven by the motor 86.

FIG. 1 shows one embodiment of the present invention, in which the surface of the protective film is processed into a spherical surface and a concentric convex lens is incorporated, showing a cross section of an m-disc.

In the figure, 10 is a disk base material such as glass, 11 is a recording medium,
Reference numerals 12 and 13 designate convex lenses having a concentric circular shape, which serve as disk protection and objective lenses. The distance between the recording medium and the convex lens is the focal length of the convex lens, and when parallel light is incident on the convex lens, it is focused on the recording medium.

Therefore, by using a beam parallel to the recording and reproducing light on the disk, a spot can always be connected on the recording medium even if the distance between the optical system of the apparatus and the disk changes due to surface wobbling or the like.

As a second embodiment, a method may be considered in which convex lenses 21 serving as protective films are arranged concentrically and radially as shown in FIG. 2. In this case as well, as in the first embodiment, by setting the distance between the lens and the recording medium as the focal point of the lens, an automatic focusing system becomes unnecessary. The drive optics for these disks move backwards.

Figure 4 shows the disc viewed from the top.

The concentric circles indicated by 41 and 42 function as lenses. The spacing between these concentric circles can be made relatively thick (on the order of millimeters) by using a scanning optical system, which will be described later.

Next, a specific example of realizing the lens function will be described. Figure 3 shows an example of implementation using a Fresnel lens. FIG. 3 is a cross-section of the disk shown in FIG. 4 cut at the gland indicated by 43.

In Fig. 3, 33 is a disk base material, 32 is a recording medium, and 31
a and 31b are Funnel lenses designed to focus on the recording medium.

Therefore, by injecting parallel light into the recording medium 31, recording on and reproduction from the recording medium becomes possible. Funnel lenses can be made relatively easily using photosensitive materials and electron beam irradiation.

FIG. 5 shows an example using a gradient index lens.

53 is a disk base material, 52 is a recording medium, and 51a.

51b is a gradient index lens.

A gradient index lens is realized by making the refractive index distribution of a transparent material such as glass parabolic as shown in FIG. This can be easily produced by an ion exchange method.

FIG. 7 illustrates an optical system for recording and reproducing a disk with an objective lens.

In the figure, 71.72 is a positioning actuator;
is in charge of radial movement with respect to the slide V disc. 75 is a galvanometer mirror, 176 is a light source for recording and reproduction,
79 is a disc body.

A recording and reproducing light source 76 is sent to a galvanometer mirror 75 as parallel light beams. The galvanometer mirror vibrates around the fulcrum 73 with a certain period, and can send parallel light beams to the lens 12 on the disk while scanning them. 7
When the mirror is at position 5, the light will follow the ray shown at 77, but when the mirror comes to position 74 at 9 o'clock, the light will follow the ray shown at 78 in the figure. Therefore, in this optical system, the optical spot can be scanned in the radial direction of the disk, and recording can be performed at high density. This situation is shown in FIG. The disk rotates at a relatively low speed and information is recorded in the radial direction by mirrors, so the information scanning trajectory is 8.
You will draw a zigzag as shown in 3.

Next, we will conduct the following experiments using the above apparatus.

An optical disk was manufactured by forming an Ag-40 heavy Si alloy film on a glass substrate using the sputtering method. In order to prevent the alloy film from being oxidized by heating during recording and erasing, and to prevent it from peeling off from the substrate, a protective film (thickness: 30 nm) of 5i (h) was formed by vapor deposition on the surface of the alloy film. For vapor deposition of alloy film, DC-Magnetron type is used.
An RF type sputtering method was applied to form each of the 5iOz films. Set the sputtering output to 140-200W and the substrate temperature to 200C. Inside the container 10-''l'□
After evacuation to about rr, p, r gas is pumped 5 to 30 m'p
□rr was introduced to prepare a thin film. The film thickness is approximately 3Q1m for SiCh film and 0.05 to 10μm for alloy film thickness.
Next, vary the thickness within the following range. The optical disk thus produced was then used for recording and erasing, and for repeating these operations. P and R gas lasers are suitable for continuous oscillation. The sample was placed on a manual movement stage, the sample was moved, and the 200 mW laser beam was focused and scanned on the film surface of the sample.

When irradiated with laser light, the hole turns pink and becomes a hole.

The alloy film, together with the substrate, has been heat-treated in advance to become silvery white. Next, the focus of the V-za light is slightly shifted from the gold film surface,
The output density of the V-za is lowered and the text is scanned in the direction intersecting the pink part (up and down in the figure). As a result, the original pink color is erased and the color changes to silvery white. It was confirmed that concave or convex portions were formed on the base surface at the same time as these color changes were recorded, and that the original flat surface returned to the original surface upon erasing.

From the above results, it was confirmed that recording and erasing can be performed using the alloy in a thin film state. It has been confirmed that this writing and erasing can be repeated any number of times.

〔Effect of the invention〕

According to the present invention, it is possible to construct an optical disk device that does not require automatic focusing. Another advantage is that since the beam is scanned in the radial direction of the disk using a galvanometer mirror, high-density and high-speed recording can be achieved even at lower disk rotational speeds.
Reproduction is possible.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of an optical disc that integrates an objective lens and a recording medium, Figure 2 is an optical disk in which spherical lenses are arranged concentrically and radially on the surface of the disc, and Figure 3 is a Fresnel lens used as an objective lens. Next time, Figure 5 will be realized using a gradient index lens, Figure 4 will be a diagram showing the ratio disk viewed from the top, Figure 6 will be a graph showing the distribution of refractive index,
Figure 7 shows the configuration of a companion optical system for recording and reproducing information on an optical disk with an integrated objective lens, Figure 8 shows the scanning order of information on the optical disk, and Figure 9 shows the optical system of a conventional optical disk device. The composition is as follows. 10...Disk base material, 11...Recording medium, 12°13...Nine lenses that serve as protection and objective lenses. Next 1 Figure 31 CL 31 & Yugo Figure 5 Figure 6 II [Device]

Claims (1)

[Claims] 1. By forming light from a light source such as a laser into a minute spot and heating it, optical properties such as optical density, optical reflectance, optical transmittance, and optical absorption rate can be changed. In a variable recording medium, an objective lens for condensing light from a light source and forming a spot is integrated with the recording medium, and the recording medium has at least two types of crystal structures in a solid state, and the recording medium has at least two types of crystal structures in a solid state, retaining the crystal structure in the other temperature range, and/or
Or an information recording medium characterized by being made of a metal or an alloy that undergoes different volume changes in a crystalline state. 2. The information recording medium according to claim 1, wherein the recording medium is made of a metal or an alloy whose crystal structure at high temperatures in a solid state is maintained by supercooling from high temperatures. 3. The recording medium is made of a metal or alloy in a crystalline state that undergoes phase transformation, and has phases with different crystal structures in at least two temperature ranges in a solid state, and there are recesses caused by the transformation between the phases. Or, by forming a convex part to change the state of light reflection with the base surface, it can be used as information such as signals, characters, figures, etc.
2. The information recording medium according to claim 1, further comprising heating means for memorizing a symbol so that it can be identified or erasing the concave or convex portion to its original state, and means for reproducing the information. 4. The recording medium contains elements from groups I, b to VII, of the periodic table.
Claims 1 to 3 consist of a metal or alloy whose main component is a transition metal element of Group B or Group VIII metal element.
The information recording medium described in any of paragraphs.