JPS5936594B2 - how to do it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to provide an information recording method capable of obtaining a large change in optical density or reflectance and a good S/N ratio.

As the amount of information has increased in recent years, there has been a desire for a method to record and reproduce these signals at high speed and high density.From this perspective, optical information recording and reproduction has recently been attracting attention. It's a method.

The following are some of the most representative ones.

The first method is to use a DrySilver i silver salt photosensitive member that does not require wet development.

In this method, light corresponding to the signal is irradiated, and then this member is heated to visualize it, form a blackened image, and record and reproduce it.It has high photosensitivity (1"2TWLJ
/cd).

However, it has the drawbacks of requiring a heat development process and being somewhat chemically unstable. Second
is a method of writing information onto a metal thin film using laser light or the like.

For example, indium metal (In) melting point Tm=156°C
Alternatively, it is known that bismuth metal (Bi) having a melting point Tm=271° C. is formed on a substrate with a thickness of about 1000λ.

The recording mechanism for this member uses a light source such as a laser to irradiate this thin film with a minute spot of ~10μφ.As a result of light absorption and temperature rise of the metal film, the metal at the spot portion melts, condenses, or evaporates. However, a minute hole is formed in this part, and the image is determined as a transparent part.

Although this material has the advantage of not requiring any development processing, it has a problem in that its sensitivity is as low as 103 to 102 mJ/cd, and that changes in optical density are accompanied by mass transfer.

A third example is an information recording and reproducing method using a semiconductor glass material. This uses a chalcogenated composition that does not contain oxygen as a recording member, such as Ge15Te.
81sb2s2, As2s3, As20Se, oGe,
Materials such as o are typical. This material has two states: an amorphous state with low optical density, that is, a microscopically regular arrangement of constituent atoms, and a macroscopically well-ordered state, and a crystalline state with high optical density. In other words, it has at least two states in which regularity is established throughout the crystal.
As a recording method, for example, a laser beam spot or the like can be irradiated onto the thin film of this material, and the material can be thermally changed from an amorphous state to a crystalline state by absorbing light and raising the temperature.

In this case, the optical density generally changes from low to high to form a signal image.

This method has the advantage that image formation occurs simultaneously with light irradiation and that the crystalline state can be changed back to the amorphous state.

However, when used in an optical information recording method, it has the disadvantage that the change in optical density accompanying the change in state is small.

In the information recording and reproducing method of the present invention, the recording member is a light-absorbing molybdenum oxide M on the surface of a base material 1, as shown in FIG.

A thin film photosensitive layer 2 containing Oxl (0<X, <3) as a main component is formed. Depending on the purpose of use, a transparent protective layer 3 may be further provided on the thin film photosensitive layer 2.

The base material 1 can be metal such as aluminum or copper, glass such as quartz, pyrex, soda glass, etc., resin, ABS resin, polystyrene, acrylic, etc., and the transparent film can be acetate, Teflon, polyester, etc. .

Among these, when an acrylic plate or the like is used for the polyester pool, it has excellent transparency and is effective in optically reproducing the formed signal image.

If the light is generated by reflection, paper or the like can be used as the base material.
The thin film photosensitive layer 2 is a light-absorbing film made of molybdenum oxide M.
.

It is mainly composed of OXl (O<.X1<3) and has a yellow-green to blue color. The film thickness may be anywhere from about 6,008 to 2 .mu.m, but a thickness in the range of 2,000.lamda.

The transparent protective layer 3 is formed, for example, by spray coating an acrylic lacquer obtained from an organic material or a liquid such as polyvinyl alcohol.

If a particularly strong protective layer is required, an inorganic material such as a SiO2 film is formed by a method such as electron beam heating evaporation. 3J 4C Molybdenum oxide M in the present invention.

The optical recording film whose main component is OXl (0<X1<3) is
It has excellent adhesion to any substrate such as organic film or aluminum foil, and has excellent adhesion to metal thin film recording materials such as Bi,
It has greater mechanical strength than an In vapor-deposited film, and depending on usage conditions, it is possible to remove the transparent protective layer 3. Next, a method for writing information in the present invention will be described.

As an example of optical writing, as shown in FIGS. 2 to 4, writing using near-infrared light using a xenon flash lamp, a gas laser such as He--Ne, or a semiconductor laser is also possible.

The aspect of the recording method when using a xenon lamp is as described in the second
Describing the embodiment shown in the figure, first, a light-absorbing molybdenum oxide M is used.

A mask 6 on which a pattern of light transmittance differs locally is brought into close contact with a recording member 5 having an optical recording film 2 mainly composed of Ox, formed on a substrate 4. By emitting and irradiating the xenon lamp 7 from above, a grayscale image corresponding to the pattern is formed on the recording member.

As another example of optical recording, a mode of writing using a gas laser light source will be described with reference to FIG.

Laser light source (human He-Ne laser λ = 6328 people, H
e-Cd laser λ2 4416λ, Ar laser λ=514
5λ etc. can be used. The laser beam 9 emitted from the laser tube 8 is modulated in intensity according to the signal by an optical modulator 10 such as LiNbO, an electro-optic optical modulator, or an ultrasonic optical modulator, etc., and is then transmitted through a mirror 11 to a converging lens 12. Molybdenum oxide M forms spots.

An optical recording member consisting of a base material 14 provided with a light-absorbing recording film 13 containing OXl as a main component is irradiated with a light intensity corresponding to a signal. As the light beam and the optical recording member move relative to each other, bit signals are sequentially written onto the recording member.

FIG. 4 shows an embodiment in which a semiconductor laser, λ=9040λ, is used as the laser light source.

Since a semiconductor laser generally has a large beam spread of the emitted laser light at an angle of ±20, first and second lenses are used to form a spot in order to shape the beam.

As the semiconductor laser 15, for example, a pulse oscillation semiconductor laser is used.

The emitted beam is transformed into pseudo-parallel light 17 by the first lens 16.
Then, a second lens 18 forms a spot light 19, and molybdenum oxide M is formed.

Base material 2 provided with a light-absorbing thin film 20 containing Ox as a main component
1 is irradiated with light intensity corresponding to the signal. When using a semiconductor laser, unlike a gas laser, internal modulation is easy and an optical modulator is not required.

Areas exposed to light turn dark blue and can be recorded as changes in optical density.

The area to which light has been irradiated changes color to deep blue or black, increases optical density, and increases light reflectance.

Next, a method for reproducing information recorded as in the present invention will be described.

The information recording thin film changes from yellow-green to blue in the unwritten state and dark blue to black in the written state, and the optical density increases and the reflectance changes.

When reading signals, as shown in the embodiments of FIGS. 5 and 6, transmission type optical signal reproduction and reflection type optical signal reproduction are possible.

The transmission type reproduction method will be explained with reference to FIG.

The illumination light source 22 can be a tungsten lamp, a He-Ne laser, a semiconductor laser, or the like, and a condensing lens 23 is used to turn the signal image 25 into a spot light 24 to illuminate the signal image 25 from the back side.
The transmitted light from the signal recording film passes through the lens 26 and becomes detection light 27 and enters the photosensitive diode 28.

The intensity of the transmitted light 27 is reduced to about 1/10 to 1/20 when illuminating a signal image compared to a state where there is no signal, and this is detected to perform signal reproduction. In FIG. 6, the reflection type reproduction method will be explained in the same way.

In this case, the illumination light is applied from the surface of the signal recording layer, unlike the transmission type. The illumination light 29 is a tungsten lamp, H
An e-Ne laser, a semiconductor laser, etc. can be used. First, the light 31 that has passed through the half mirror 30 is focused by the lens 32 and illuminates the signal image 33. Next, the light reflected from the signal image 33 passes through the lens 32, is reflected by the half mirror 30, and enters the photosensitive diode 36 through the lens 35 as reflected light 34.

The intensity of the reflected light 34 increases approximately two to three times when a signal image is illuminated compared to when there is no signal, and this is detected to perform signal reproduction.

Next, a method for manufacturing an information recording member applied to the information recording and reproducing method of the present invention will be described. When a vapor deposition method is applied as a method of the embodiment, a component having the following compositional formula is used as an example of a starting material for vapor deposition.
−J′−! 1 M2: Additive material R: Reducing material However, X and y are mol% O<y<100,0<x<1
As the 001 additive material M2, PbO, In2O3'S
nOPB2O3! Sb2O3 la Bi2O3 bow TeO2,
At least one of SiO and GeO2 is used.

As the reducing material R, at least one of Cr, Fe, W, and Mn is used.

A procedure for forming a light-absorbing recording member using this vapor deposition starting material will be described.

First, the main component, the raw material molybdenum oxide MOO3, has a heating temperature of 795°C and is a white powder with an orthorhombic crystal system.In contrast, the second additive material M2 powder and these A reducing material R that causes a reducing reaction to the material is selected and mixed.

Using the generation system shown in Figure 7, the degree of vacuum in the vacuum system 37 is 10-3.
Choose between TrmHg and 10-6 mHg. Base material for vapor deposition 3
The material 8 can be made of metal, glass, organic film, paper, etc., and is provided on the substrate support 40 . Heating vapor deposition container 44
can use quartz crucibles, platinum, alumina porcelain, etc.
What is the starting material for vapor deposition? Reaction vapor deposition temperature 700℃~1000℃
Select a material that is stable and does not cause any reaction.

As another mode of use, the material of the container is utilized as the reducing material R.

For example, it is also possible to use a W boat or a Ti boat. The vapor deposition starting material 45 is placed in the container 44 , a heating coil heater 42 is connected to the electrode 41 in the vacuum system 37 , and the material is heated using the power source 43 .

As for the heating method, the container is placed in a basket of Kanthal wire or tungsten wire coil, or in a boat, and a current resistance heating method is used. Another method is to directly heat the mixture using a microwave oven or the like.

The heating temperature varies depending on the additive material component M2, but is 700
Select from a range of ℃ to 1000℃.

Under the above vacuum degree and heating temperature conditions, the vapor deposition raw material in the container 44 is heated, reacts, melts, elevates and evaporates, and becomes the vapor deposition substrate 38.
A light-absorbing recording film 39 is formed thereon.

The thickness of the deposited film can be changed depending on the amount of raw materials, the deposition area, etc., and can be easily controlled in the range of 1000 to 2μ, and can be set depending on the application.

Next, the structure of the light-absorbing recording thin film formed by vapor deposition will be described. First, the compositional formula of the starting raw material for vapor deposition is, and upon heating in vacuum, the reducing material R becomes, respectively.
It reacts with the molybdenum oxide MOO3 and the oxide additive material M2, takes in some oxygen from both, and converts each into a low oxide form.

In other words, the following reaction production process occurs.

And, for example, when the oxide additive material M2 is a tetravalent metal oxide, this additive material is an oxide type of MO2,
The evaporation product film is a low oxide MO produced in the above reduction reaction process.
It is obtained as a mixed film of OXl and MOX2.

In general, reduced low oxides of metal oxides exhibit light absorbing properties and the resulting film is obtained as a light absorbing recording thin film.

However, in this case, the reactive material R is not necessarily included in this produced thin film. The thin film obtained by the above method exhibits a yellow-green to blue color, and has a characteristic that the optical density changes to deep blue when energy is applied, for example, by light irradiation.

The sensitivity of this information recording/reproducing member can be changed by changing the material composition of the light-absorbing recording film as well as the constituent elements of the member.

For example, it is desirable to select a base material with low thermal conductivity and specific heat, compared to glass.
Organic film is better.

Furthermore, the smaller the heat capacity of the base material, the higher the efficiency of light absorption and temperature rise of the recording film, so it is desirable that the base material be thinner.

Molybdenum oxide MOOXl (0<X,
In the information recording method using a light-absorbing thin film mainly composed of In some cases, it is possible to obtain an even greater contrast ratio by selecting the thickness of the thin film.
A contrast ratio of 20:1 or more can be obtained with a film thickness of 3000 to 7000.

On the other hand, when reproducing this signal image using transmitted light, signal readout efficiency is improved by increasing the transmittance of the unrecorded portion, and good results are obtained in the relatively thin film thickness range of 1,000 to 3,000 yen. get.

Example 1 Molybdenum trioxide MOO alone was used as the vapor deposition raw material, and at least one of Cr, Fe, W, and Mn was used as the reducing material.
An example will be described in which the film is formed by vapor deposition.

A transparent polyester film having a thickness of 25 μm is used as the base material 1 in FIG.

The thin film photosensitive layer 2 exhibits a color ranging from yellow-green to light blue, and is composed of molybdenum oxide MOOX1, where 0〈x〈3. Although reactive material components may be mixed into the thin film photosensitive layer as impurities, they have little effect on information recording characteristics.Next, we will discuss a method for forming information recording films using molybdenum trioxide alone and reducing materials.Vapor deposition An example of a raw material composition formula is the following formula.

(MOO3)100-XRx where O<x<100 Furthermore, R is a reducing material component and is at least one of Cr, Fe, W, and Mn.

Using the generation system shown in Figure 6, the degree of vacuum in the vacuum system 37 is 10-3.
~10-6ml/g.

The vapor deposition base material 38 is a transparent polyester film and has a thickness of 25 μm.

The heating vapor deposition container 44 is a quartz crucible.

In this, a mixed powder of molybdenum trioxide MOO3 and chromium Cr selected as the reducing material component R and added at a composition ratio of 40 moles (fl) (x=40) to MOO3 is placed. The weight of the mixed powder vapor deposition raw material can be selected depending on the desired thickness of the vapor deposited film.

By using about 10,077V, a film thickness of about 7,000 people is obtained.

A tungsten basket is used as the heater 42. Vapor deposition is easily carried out at a vapor deposition heating temperature in the range of 700°C to 1000°C.

The film produced using molybdenum alone and a reducing material is MO
OXl, however, can be obtained in the composition range of O<X, <3.

The deposited film is yellow-green, and the spectral transmittance curve of this thin film is 40 (Ff) in the visible light wavelength region, as shown by curve a1 in Figure 8.
It has a transmittance of

When this film is closely attached with a mask and irradiated with a Xe flash lamp, as shown in FIG. changes to deep blue and the optical density increases. When the color changes from yellow-green to deep blue, a change in density that matches the visibility can be obtained. In the spectral transmittance curve of the film after recording, as shown by curve A5 in FIG. 8, the transmittance decreases and the absorption increases significantly in the range from 6000λ to 1.2μ on the long wavelength side from the red.

Similarly, the optical recording films formed by vapor deposition using Fe, W, and Mn as reducing materials R exhibit yellow-green to light blue colors in the unrecorded state, and the curves A2, a3, and a in FIG.
The spectral transmittance curve is shown in 4.

The concentration of the produced film varies depending on the reducing material, and Mn, W, F
The concentration tends to decrease in the order of e and Cr. In both cases, the optical density increases by light irradiation, and the spectral transmittance curves after recording decrease in transmittance as shown by curves A6, a7, and a8 in FIG. 8, so that information can be recorded and reproduced optically. Similar results can be obtained by using At, Cu, Zn, Ti, C, etc. as the reducing material.

Example 2 Molybdenum trioxide MOO3 was used as the vapor deposition material, and metal oxides TeO2, Sb2O3, Bi were used as the additive material M2.
The optical information recording film formed by vapor deposition using at least one of 2O3 and Cr selected as a reducing material uses a transparent polyester film having a thickness of 25 μm as the base material 1 in FIG.

The thin film photosensitive layer 2 has a pale blue color, and the main component is MOOx.
,,O<X1×3, and contains an additive metal oxide as a subcomponent in the form of a low oxide.

The component used as the reducing material is not necessarily included in the vapor deposition recording thin film layer 2. Next, molybdenum trioxide MOO
3, and a method for producing an optical recording film using metal oxides as additive materials.

An example of a vapor deposition raw material composition formula is the following formula, where R is a reducing material component, and the material used in Example 1 can be applied, but in this example, an example using Cr will be described.

M2 is an additive material component, TeO2, snO, Sb2O
3, Bi2O3.

Using the generation system shown in FIG. 7, the vacuum degree of the vacuum system 37 is 10-
3mHg to 1[6wr1nHg.

The deposition substrate 38 is a transparent polyester film with a film thickness of 25 μm. The heating vapor deposition container 44 is a quartz crucible. Into this, molybdenum trioxide MOO3 and TeO2 were selected as additive material components and added at a composition ratio of 6 mol% (y=6) to MOO3, and the mixture was solid-dissolved at about 750°C. , powder, and a mixed powder in which Cr, which is a reducing material component, is added at a composition ratio of 40 mol % (x=40) of the total is added.

The weight of this mixed powder vapor deposition raw material can be selected depending on the set thickness of the vapor deposited film. By using approximately 507!9, a film thickness of 4000λ is obtained.

A tungsten basket is used as a heating heater.

Vapor deposition is easily carried out at a vapor deposition heating temperature in the range of 700°C to 1000°C. The process of forming the thin film is thermal reaction vapor deposition in vacuum, and involves the following steps.

Tl4-λ2-b Low oxides of MOOXl and TeOX2, respectively produced by reduction, are deposited to form a mixed film, and a film having a composition of Tl4-λ2-b is obtained.

The deposited film has a light blue color, and the spectral transmittance curve of this thin film has a transmittance of 30% or more in the visible light wavelength region, as shown by curve b1 in FIG.

Although the transmittance is lower than that of the film described in Example 1, information recording films having various initial transmittances can be formed by selecting the film thickness.

As an example of optical recording on this film, the embodiment shown in FIG. 4 uses a semiconductor laser as a writing light source.

Upon light irradiation, the vapor deposited thin film layer 20 changes to a dark blue color, and its concentration increases as the power of the semiconductor laser increases.

Similarly, optical density changes can also be obtained by light irradiation with a Xe flash lamp, and the spectral transmittance curve of the film after this recording is 6000λ on the long wavelength side from red, as shown by B5 in FIG. Absorption increases significantly between ~1.2μ, and a contrast ratio of 20:1 is obtained at the He-Ne laser light wavelength λ=6328λ, and similarly at the semiconductor laser wavelength λ-9
Even at a near-infrared wavelength of 040A, a contrast ratio of 10:1 can be obtained.

Similarly, as the additive material oxide M2, B2O3, Sb2O3
, Bi2O3, and which contain these in the form of low oxides, each has MOOXl as a main component and is an oxide film in the form of O<z100.

These information recording films are pale blue or blue in the unrecorded state, and their respective spectral transmittance curves are curve B in FIG.
As shown by 2, b3, and b4, absorption is relatively large on the long wavelength side from red. Films optically recorded using a Xe flash lamp each have a deep blue color and an increased optical density.

The spectral transmittance curves of the film after writing are curves B6, b7, and b8 in FIG. 9 corresponding to the additive materials B2O3, Sb2O3, and Bi2O3, respectively. The film containing these additive materials has a feature that compared to Example 1, the information writing contrast ratio is 20:1, and the sensitivity is increased by 4 to 5 times. Similarly, the reflection contrast ratio increases to a value of 3:1. The information recording and reproducing method of the present invention uses a recording thin film mainly composed of molybdenum oxide MOOXlO<X, 3, and has the following effects compared to methods using a Bi metal vapor deposited thin film or a chalcogenated material thin film. have.

(1) While the chalcogenated composition that achieves a large change in optical density has a contrast ratio of about 4:1, the recording film of the present invention obtains a contrast ratio that is about 5 times larger and reaches 20:1, resulting in an optical contrast ratio of about 4:1. When reproducing a signal, a high S/N ratio can be obtained.

(2) Reflection type reading is possible A 3:1 reflected light amount ratio can be obtained between the writing section and the non-writing section.

(3) Recording/reading is possible even at near-infrared wavelength λ-90408.

In the chalcogenated composition, in this wavelength range, the transmitted light quantity ratio decreases to 2:1 between the written area and the unwritten area, but with the recording film of the present application, signal reproduction can be performed with a large light quantity ratio of 10:1.

(4) A recorded state with a high light transmittance of 20% to 300 I in the unrecorded area can be obtained.

(5) A recording film with mechanical strength and chemical stability is
It has an oxide composition and is stable in air.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a recording medium used in the information recording method of the present invention, and FIG. 2 is a schematic diagram showing an embodiment of the recording method of the present invention.
Figures 3 and 4 are schematic diagrams of other embodiments of the recording method of the present invention, Figures 5 and 6 are schematic diagrams of the reproduction method, respectively, and Figure 7 is a schematic diagram of the optical information recording film of the recording medium. 8 is a diagram showing the spectral transmittance curve of the optical information recording film of Example 1 before and after recording, and FIG. 9 is a diagram showing the spectral transmittance curve of the optical information recording film of Example 2 before and after recording. It is a figure showing a spectral transmittance curve. 1...Substrate, 2...MOOxl(0<
A thin film containing X, <3) as a main component, 3...Transparent protective layer.

Claims (1)

[Claims] 1 Light-absorbing molybdenum oxide M_oOx_1 (O<
An information recording method characterized by applying energy having an intensity change corresponding to a signal to a thin film whose main component is x_1≦3), causing a change in optical density or a change in reflectance, and forming a signal image.