JPH0714207A - Optical recording medium - Google Patents

Abstract

PURPOSE:To provide an optical recording medium on which information can be recorded in a highly superimposing state and from which the recorded information can be reproduced by such a method that can secure the secret of the information. CONSTITUTION:An ultraviolet light absorbing film 2, optical functional film 3, and protective film 4 are successively formed on a substrate 1. The substrate 1 is composed of a brown glass which can absorb ultraviolet light and the ultraviolet light absorbing film 2 has a high absorbancy to ultraviolet light. The photo-functional film 3 is formed by applying polystyrene in which a prescribed photo-functional dye is uniformly dispersed by a solvent casting method using toluene as a solvent, by an ordinary method, such as the spin coating method, etc. The protective film 4 is an oxygen barrier film made of polyvinyl alcohol, etc., which obstructs the supply of oxygen to the film 3. For example, benzyl, benzophenone, anthracene, etc., which exhibit light transient absorption characteristic when they are excited with light having a prescribed wavelength can be used as the optical functional dye dispersed in the film 3. Since these dyes cause optical deterioration when they are exposed to ultraviolet light under the presence of oxygen, recorded sections 31 and unrecorded sections 32 are two- dimensionally arranged in the film 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium which records information by light irradiation and reproduces this information by time-resolved measurement of transient absorption characteristics.

[0002]

2. Description of the Related Art Conventionally, various methods have been used to measure the properties of substances. For example, measuring means such as ultraviolet-visible absorption, fluorescence, infrared absorption, mass spectrum, NMR spectrum and elemental analysis are applied not only in synthetic organic chemistry but also in various fields such as engineering, biology, medicine and environment. . Among these, spectroscopic measurement that utilizes optical properties such as absorption, scattering, and emission of a substance, especially under conditions that require nondestructive and noninvasive measurement without impairing the shape of the substance. However, it is generally limited to measurement of UV-visible absorption, scattering and fluorescence. Therefore, the method of optically recording and reproducing information on a substance utilizes changes in absorbance, reflectance, transmittance, and fluorescence intensity.

As an optical recording medium by such a method, there is one in which a recording film whose light transmittance changes according to the wavelength of irradiation light is formed on a substrate. In this recording film, the amount of products produced by the photochemical reaction due to light irradiation differs depending on the wavelength. Therefore, if a laser that selectively excites a specific wavelength in the light absorption band of the recording film is used, portions having different light transmittances are formed in dots on the recording film, and information is recorded. The information is reproduced by irradiating the optical recording medium with a monitor light having a specific wavelength and detecting the transmitted light or the reflected light. Therefore, according to this optical recording medium, a large amount of information can be recorded / reproduced by wavelength multiplexing.

Regarding the technique described above, Japanese Unexamined Patent Publication No.
It is described in detail in Japanese Patent No. 2767.

[0005]

According to the above-mentioned conventional optical recording medium, predetermined information is recorded by forming different light transmittance distributions on the recording film according to the wavelength of the irradiation light. However, by irradiating this recording film with a monitor light of a specific wavelength and measuring the transmittance or the reflectance,
Predetermined information is easily reproduced. Therefore, there is a problem that reliability is low for holding highly confidential information.

The information recorded on this recording film is multi-valued depending only on the wavelength of the irradiation light. Therefore, there is a problem that the multiplicity of held information is low.

Therefore, the present invention has been made in view of the above problems, and an optical recording medium in which information is recorded with high multiplicity and this information is reproduced by a method of maintaining confidentiality. The purpose is to provide.

[0008]

In order to achieve the above object, the present invention provides an optical recording medium including a substrate and an optical functional film formed on the substrate. Has a light transient absorption characteristic in the excited state which transits transiently by the irradiation of the first wavelength light, and the recording portion which has lost the light transient absorption characteristic by the light irradiation of the second wavelength, and the light transient absorption characteristic. It is characterized in that an unrecorded portion holding characteristics is arranged corresponding to predetermined information.

In order to achieve the above object, the present invention further comprises an optical recording medium comprising a substrate and a plurality of optical functional films and protective films which are sequentially laminated on the substrate. In the above, the optical functional films respectively have different optical transient absorption characteristics in the excited state that transits transiently by the irradiation of the first wavelength, and the optical functional films have the optical transient absorption characteristics by the irradiation of the second wavelength. The disappeared recording portion and the unrecorded portion that retains the light transient absorption characteristic are arranged corresponding to predetermined information, and the protective film has a light absorption characteristic of absorbing the light of the second wavelength, It is characterized in that the oxygen supply to the photofunctional film is controlled respectively.

The recording section is characterized in that the light transient absorption characteristic disappears due to photodegradation in which light of the second wavelength and oxygen react.

Further, the optical functional films are characterized in that they have optical transient absorption characteristics in which absorption wavelength bands or time profiles are different from each other.

[0012]

According to the present invention, the optical functional film is formed on the substrate, and has an optical transient absorption characteristic in the excited state in which the light having the first wavelength is irradiated and transitions transiently. When this optical functional film is irradiated with light of the second wavelength in a distribution corresponding to predetermined information, a recording portion in which the optical transient absorption characteristic disappears due to photodegradation corresponding to the distribution is formed. Therefore, predetermined information is recorded as a two-dimensional array of photo-deteriorated portions in the optical functional film.

The portion of the optical functional film excluding the recording portion is left as an unrecorded portion that retains the light transient absorption characteristics. Therefore, when the optical functional film is irradiated with the light of the first wavelength, the unrecorded portion transits to the excited state transiently,
The recording unit does not transition to the excited state.

Further, when the optical functional film is irradiated with light of the first wavelength and then predetermined light is irradiated at a timing corresponding to the time profile of the light transient absorption characteristic in the unrecorded portion,
The light that has entered the unrecorded portion is absorbed and transmitted in a predetermined wavelength band. On the other hand, the light incident on the recording portion is not absorbed in a predetermined wavelength band but is transmitted. Therefore, by performing time-resolved measurement of light that has passed through each position of the optical functional film, predetermined information is reproduced corresponding to detection of light intensity in a predetermined wavelength band.

Further, according to the present invention, first, the first optical functional film is formed on the substrate, and the light transient absorption characteristic is obtained in the excited state in which the light having the first wavelength is irradiated to make a transient transition. Have. When the first optical functional film is irradiated with the light of the second wavelength in the distribution corresponding to the first information, the recording portion in which the optical transient absorption characteristic disappears is formed corresponding to the distribution. Therefore, the first information is recorded as a two-dimensional array of recording parts in the optical functional film.

Next, the first protective film and the second optical functional film are sequentially formed on the first optical functional film. The second optical functional film has an optical transient absorption characteristic different from that of the first optical functional film in the excited state in which the light having the first wavelength is irradiated and transitions transiently. When the second optical functional film is irradiated with the light of the second wavelength in the distribution corresponding to the second information, the recording portion in which the light transient absorption characteristic disappears is formed corresponding to the distribution, and the second wavelength Light is absorbed by the first protective film. Therefore, the second information is recorded as a two-dimensional array of recording portions in the optical functional film, and the recording portions and unrecorded portions in the first optical functional film are retained as they are.

Similarly, the second protective film and the third optical functional film are sequentially formed on the second optical functional film, and the above operation is repeated. As a result, the predetermined plurality of pieces of information are recorded as a three-dimensional array of recording portions in each optical functional film.

The portion of each optical functional film excluding the recording portion is left as an unrecorded portion that retains the light transient absorption characteristics. Therefore, when each optical functional film is irradiated with the light of the first wavelength, the unrecorded portion transits to the excited state transiently,
The recording unit does not transition to the excited state.

Furthermore, after irradiating each optical functional film with the light of the first wavelength, a predetermined light is irradiated at a timing corresponding to the time profile of the light transient absorption characteristic in the recording section.
The light that has entered the unrecorded portion is absorbed and transmitted in a predetermined wavelength band. On the other hand, the light incident on the recording portion is not absorbed in a predetermined wavelength band but is transmitted. Therefore, by performing time-resolved measurement of the light that has passed through the respective positions of the respective optical functional films, a predetermined plurality of information is reproduced corresponding to the detection of the light intensity in the predetermined wavelength band.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and operation of an embodiment according to the present invention will be described below with reference to FIGS. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description. Further, the dimensional ratios in the drawings do not always match those described.

FIG. 1A shows the structure of the first embodiment of the optical recording medium of the present invention. In this optical recording medium, the substrate 1
An ultraviolet light absorbing film 2, an optical functional film 3, and a protective film 4 are sequentially formed on the top. The substrate 1 is brown glass that absorbs ultraviolet light. Further, the ultraviolet light absorption film 2 has a large absorbance for ultraviolet light. Further, the optical functional film 3 is formed by a usual method such as spin coating in which a predetermined optical functional dye α is dispersed almost uniformly in polystyrene by a solvent casting method using toluene as a solvent. further,
The protective film 4 is an oxygen impermeable film such as polyvinyl alcohol formed from an aqueous solution by a solvent casting method,
The supply of oxygen to the optical functional film 3 is hindered.

The photofunctional dye α in the photofunctional film 3 is used.
Has a light transient absorption property when excited by irradiation with light having a predetermined wavelength, and examples thereof include benzyl, benzophenone, and anthracene represented by the following chemical formulas.

[0023]

[Chemical 1]

[0024]

[Chemical 2]

[0025]

[Chemical 3]

Since the photo-functional dye α causes photo-deterioration due to exposure to ultraviolet light in the presence of oxygen and loses its light transient absorption property, the photo-functional film 3 has a recorded portion 31 and an unrecorded portion 3.
2 are arranged two-dimensionally. In addition, a binder layer may be formed between the films.

FIG. 2 shows the optical recording method of the first embodiment of the optical recording medium of the present invention. First, the ultraviolet light absorbing film 2 and the optical functional film 3 are sequentially formed on the substrate 1 (FIG. 2A).

Next, the mask 7 is arranged above the optical functional film 3. Next, under an oxygen atmosphere, that is, under the atmosphere,
The optical functional film 3 is exposed by irradiating the ultraviolet light 11 having a predetermined wavelength λ ₁ from above the mask 7 (FIG. 2B). For example, the ultraviolet light 11 has a wavelength of 310 nm and a light quantity of 0.5 J / cm ² .

The mask 7 has a two-dimensional array of a non-mask portion 71 that absorbs ultraviolet light and a mask portion 72 that transmits ultraviolet light to form a mask pattern corresponding to predetermined information. The ultraviolet light 11 that has passed through the non-mask portion 71 of the mask 7 causes photodegradation at the position where it passes through the optical functional film 3, and is absorbed by the ultraviolet light absorbing film 2. On the other hand, the ultraviolet light 11 incident on the mask portion 72 of the mask 7 is absorbed and does not cause photodegradation at the position of the optical functional film 3 along the traveling direction thereof. Therefore, in the optical functional film 3, the recorded portion 31 and the unrecorded portion 32 correspond to the mask pattern of the mask 7.
Are arranged two-dimensionally, so that predetermined information is recorded.

FIG. 4A shows the recording state of the first embodiment of the optical recording medium of the present invention. For example, the photofunctional dye α in the photofunctional film 3 is benzyl. In the area A, the unrecorded portion 32 of the optical functional film 3 is arranged. In the area B, the recording section 31 of the optical functional film 3 is arranged.
In this case, the predetermined information is the area A in the optical functional film 3.
It is expressed in the shape of.

Next, a protective film 4 is formed on the optical functional film 3 (FIG. 2 (c)). Since the supply of oxygen is blocked by the protective film 4 in the photofunctional film 3, further photodegradation is not promoted. Therefore, the predetermined information recorded on the optical functional film 3 is favorably stored.

FIG. 1B shows the structure of the second embodiment of the optical recording medium of the present invention. This optical recording medium has substantially the same structure as the optical recording medium of the first embodiment. However, the optical functional film 5 and the protective film 6 are sequentially formed on the protective film 4. The photo-functional film 5 is doped with the photo-functional dye β having different optical transient absorption characteristics with respect to the photo-functional dye α in the photo-functional film 3, and is formed in the same manner as the photo-functional film 3. There is. Further, the protective film 6 is an oxygen impermeable film such as polyvinyl alcohol formed from an aqueous solution by a solvent casting method, and prevents the supply of oxygen to the optical functional film 5.

The photo-functional dye β in the photo-functional film 5 causes photo-degradation due to exposure to ultraviolet light in the presence of oxygen and loses its light transient absorption characteristics. 5
1 and the unrecorded portion 52 are arranged two-dimensionally. In addition, a binder layer may be formed between the films.

Here, in order to record a predetermined plurality of information on the optical functional films 3 and 5 by wavelength multiplexing, optical functional dyes α and β having optical transient absorption characteristics different in absorption wavelength band are used. For example, for benzyl and benzophenone, the transient absorption wavelength bands are around 480 nm and 520 nm, respectively. Further, in order to record predetermined plural pieces of information on the optical functional films 3 and 5 in a time-multiplexed manner, the optical functional dyes α and β having optical transient absorption characteristics having different time profiles are used. For example, in the case of anthracene and benzophenone, the arrival times of maximum absorbance after excitation are relatively different.

FIG. 3 shows an optical recording method according to the second embodiment of the optical recording medium of the present invention. First, the ultraviolet light absorption film 2 and the optical functional film 3 are sequentially formed on the substrate 1 (FIG. 3A).

Next, the mask 7 is arranged above the optical functional film 3. Next, under an oxygen atmosphere, that is, under the atmosphere,
The optical functional film 3 is exposed by irradiating the ultraviolet light 11 having a predetermined wavelength λ ₁ from above the mask 7 (FIG. 3B). For example, the ultraviolet light 11 has a wavelength of 310 nm and a light quantity of 0.5 J / cm ² .

The mask 7 has a non-mask portion 71 absorbing ultraviolet light and a mask portion 72 transmitting ultraviolet light two-dimensionally arranged to form a mask pattern corresponding to the first information. Therefore, in the optical functional film 3, as in the optical recording medium of the first embodiment, the recording portion 31 and the unrecorded portion 3 are formed.
2 are arranged two-dimensionally and the first information is recorded.

Next, the protective film 4 and the optical functional film 5 are sequentially formed on the optical functional film 3 (FIG. 3C). Optical functional film 3
Since the oxygen supply is blocked by the protective film 4,
Further, it does not promote photodegradation. Therefore, the optical functional film 3
The first information recorded in is well preserved.

Next, the mask 8 is placed above the optical functional film 5. Next, under an oxygen atmosphere, that is, under the atmosphere,
The optical functional film 5 is exposed by irradiating the ultraviolet light 12 having a predetermined wavelength λ ₂ from above the mask 5 (FIG. 3D). For example, the ultraviolet light 12 has a wavelength of 310 nm and a light quantity of 0.5 J / cm ² .

The mask 8 has a non-mask portion 81 for absorbing ultraviolet light and a mask portion 82 for transmitting ultraviolet light which are two-dimensionally arranged to form a mask pattern corresponding to predetermined second information. The ultraviolet light 12 that has passed through the non-mask portion 81 of the mask 8 causes photodegradation at the position where it passes through the optical functional film 5. On the other hand, the ultraviolet light 12 incident on the mask portion 82 of the mask 8 is absorbed and does not cause photodegradation at the position of the optical functional film 5 along the traveling direction thereof. Therefore,
In the optical functional film 5, the recorded portions 51 and the unrecorded portions 52 are two-dimensionally arranged corresponding to the mask pattern of the mask 5, so that the second information is recorded.

FIG. 4B shows the recording state of the second embodiment of the optical recording medium of the present invention. In the case of wavelength multiplexing recording, the photofunctional dyes α and β in the photofunctional films 3 and 5 are benzyl and benzophenone, respectively. Further, in the case of time-division recording, the photofunctional dyes α and β in the photofunctional films 3 and 5 are
Are anthracene and benzophenone, respectively.

In the area C, the unrecorded portion 32 of the optical functional film 3 is recorded.
And the recording portion 51 of the optical functional film 5 are laminated and arranged. Further, in the area D, the recording portion 31 of the optical functional film 3 is formed.
And the unrecorded portion 52 of the optical functional film 5 are stacked and arranged. Further, in the area E, the unrecorded portion 3 of the optical functional film 3 is
2 and the unrecorded portion 52 of the optical functional film 5 are laminated and arranged. Further, in the region F, the recording portion 31 of the optical functional film 3 and the recording portion 51 of the optical functional film 5 are arranged in a stacked manner.

In this case, the first information is represented by the shape of the region C in the optical functional film 3. The second information is represented by the shape of the area D in the optical functional film 3. Furthermore, the third information, which is a combination of the first and second information, is represented by the shape of the region E in the optical functional films 3 and 5.

Next, a protective film 6 is formed on the optical functional film 5 (FIG. 3 (e)). Since the supply of oxygen is blocked by the protective film 6 in the photofunctional film 5, further photodegradation is not promoted. Therefore, the second information recorded on the optical functional film 6 is favorably stored.

FIG. 5 shows the configuration of an embodiment of the optical recording / reproducing apparatus of the present invention. The monitor light generator 21 is a xenon flash lamp that oscillates with a pulse width of 1 ms.
A convex lens 24a, an optical recording medium 26, a bandpass filter 27, a convex lens 24b, and a monitor light detector 28 are arranged in a line along the traveling direction of the monitor light emitted from the monitor light generator 1.

The convex lens 24a is arranged so that the light emitting portion of the monitor light generator 21 is located at the front focus thereof. Further, the optical recording medium 26 is the one shown in the above-mentioned embodiments in which predetermined information is recorded. This optical recording medium 26
Is installed on a stage (not shown) that is movable on a plane orthogonal to the chief ray of the monitor light such that the stacking direction of the optical functional film is parallel to the chief ray of the monitor light,
The predetermined position is located at the rear focal point of the convex lens 24a.

The bandpass filter 27 is used for the optical recording medium 2
6 is an interference filter having a light absorption wavelength of the optical functional dye doped in the optical functional film of No. 6 as a central wavelength and a half width of about 6 nm. The bandpass filter 27 is replaced according to the transient absorption wavelength of the optical functional dye in the optical recording medium 26. The bandpass filter 27 is
When the monitor light detection device 28 is a streak camera,
It may be replaced with a spectroscope that performs wavelength dispersion in the slit axis direction. Further, the convex lens 24b is arranged such that a predetermined position of the optical recording medium 26 is located at the front focus thereof.

The monitor light detecting device 28 includes a convex lens 24b.
It is arranged so that the light receiving portion is located at the rear focal point. If the pulse width of the monitor light emitted from the monitor light generator 21 is shorter than the life of the excited state of the optical functional dye in the optical recording medium 26, the monitor light detector 28 need not have time resolution. An ordinary photodiode or the like is used. On the other hand, when the pulse width of the monitor light is longer than the life of the excited state of the optical functional dye in the optical recording medium 26, or when the monitor light is continuous light, a streak camera or the like having a time resolution is used.

The excitation light generator 22 is a YAG laser which oscillates as a third harmonic with a wavelength of 355 nm and a pulse width of 6 ns. Mirrors 25a and 25b are arranged along the traveling direction of the excitation light emitted from the excitation light generator 22. The mirror 25a is arranged such that its mirror surface reflects the excitation light emitted from the light emitting section of the excitation light generator 2 toward the mirror surface of the mirror 25b. Also, mirror 2
5b is arranged such that its mirror surface irradiates the region including a predetermined position on the optical recording medium 26 with the excitation light reflected by the mirror surface of the mirror 25a.

The control device 23 has its output section electrically connected to the monitor light generator 21, the excitation light generator 22, and the drive parts of the stage and monitor light detector 28 (not shown), and serves as a timing controller. The light emission signal, the scanning signal, or the detection signal is synchronously output to. The input unit of the display device 29 is electrically connected to the output unit of the monitor light detection device 28, and an electric signal output from the monitor light detection device 28 is output to the memory unit as a streak image analysis device or a monitor. Is stored as pixel data in synchronization with the scanning signal, and the predetermined information recorded on the optical recording medium 26 is imaged on the display section.

FIG. 6A shows the recording / reproducing method of the first embodiment of the optical recording medium of the present invention. First, the control device 27
The excitation light generator 22 emits the excitation light 13 from the light emitting portion at a predetermined time based on the light emission signal output from the device. The excitation light 13 has a predetermined wavelength λ ₃ included in the absorption wavelength band of the optical functional dye α in the optical functional film 3 of the optical recording medium 26. For example, when the photofunctional dye α is benzyl, the wavelength of the excitation light 13 is 355 nm.

FIG. 7 shows the measurement result of the absorption spectrum of the photofunctional film in the steady state. This photofunctional film is made of polystyrene and is doped with benzyl as a photofunctional dye. The content of benzyl is 5% by weight with respect to polystyrene. The film thickness of the optical functional film is about 20 μm. According to this absorption spectrum,
It can be seen that light with a wavelength of 355 nm is included in the absorption wavelength band in the steady state.

Next, the excitation light 13 is reflected by the mirrors 25a and 25a.
It is reflected by b and is incident on a region of the optical recording medium 26 including a predetermined position on the protective film 4. The excitation light 13 is applied to the protective film 4
Is partially absorbed by the optical functional film 3, is transmitted through the ultraviolet light absorbing film 2 and the substrate 1, and is mostly absorbed by the bandpass filter 27. The photofunctional dye α in the photofunctional film 3 that has absorbed the excitation light 13 highly efficiently transits to a metastable excited singlet state or excited triplet state, and is excited for several tens of μs under deaeration. Holds the life of and returns to the steady state. For example, when the photo-functional dye α is benzyl, it transitions to the excited triplet state with high efficiency. The lifetime of the photofunctional dye α in the excited state is greatly affected by oxygen in the atmosphere.

FIG. 8 shows the results of measurement of the light transient absorption characteristics of the optical functional film. (A) is the absorption spectrum at 3 μs after excitation, (b) is the time profile of the absorbance in the wavelength band 450 to 510 nm. Is. This optical functional film shows the absorption spectrum in the steady state in FIG. According to the absorption spectrum of the excited state, the wavelength band 450
A large absorbance of more than 0.1 appears around ˜510 nm, indicating that the excited triplet state has a large absorption coefficient. Further, according to the time change of the absorbance in this wavelength band, the absorbance reaches a maximum for several μs after the excitation, then gradually attenuates and returns to the steady state after a tens of μs after the excitation. Therefore, the optical transient absorption characteristics of this optical functional film are
It can be seen that it appears in the wavelength band of 450 to 510 nm when the lifetime of the excited state is ten and several μs.

Next, based on the light emission signal output from the controller 27, the monitor light generator 21 emits the monitor light 14 from the light emitting portion at a predetermined time synchronized with the excitation light generation time. When the pulse width of the monitor light 14 is shorter than the lifetime of the excited state of the photofunctional dye α, the monitor light 14 is generated at the maximum absorbance arrival time of the photofunctional dye α. In addition, the monitor light 14
Is generated in a predetermined range including the generation time of the excitation light 13 and the maximum absorbance arrival time of the photofunctional dye α when the pulse width is longer than the excitation lifetime of the photofunctional dye α or continuous light. It This monitor light 14 is generated by the convex lens 2
The light is condensed by 4a, a spot is formed on the protective film 4 of the optical recording medium 26 at a predetermined position, and the spot is sequentially transmitted through the protective film 4, the optical functional film 3, the ultraviolet light absorbing film 2 and the substrate 1.

However, the monitor light 14 incident on the non-deteriorated portion 32 of the optical functional film 3 is included in the transient absorption wavelength band of the optical functional dye α when the optical functional dye α is transited to the excited state. The light component having the predetermined wavelength λ ₄ is absorbed. On the other hand, the monitor light 14 incident on the photo-deteriorated portion 31 of the optical functional film 3 passes through the optical functional film 3 without absorbing the optical component of the predetermined wavelength λ ₄ .

Next, the monitor light 14 that has passed through the optical recording medium 26 passes through a bandpass filter 27 whose center wavelength is a predetermined wavelength λ ₄ included in the transient absorption wavelength band of the optical functional dye α. With this bandpass filter 27, monitor light 1
4 absorbs light components other than the predetermined wavelength λ ₄ . For example, when the optical functional dye α in the optical recording medium 26 is benzyl, the center wavelength of the bandpass filter 27 is 480n.
It should be m. The monitor light 14 has a convex lens 24a.
And is received by the light receiving unit of the monitor light detection device 28.

FIG. 9 shows a recording / reproducing method of the first embodiment according to the optical recording medium of the present invention. (A) is a monitor light pulse,
(B) is a pumping light pulse, (c) is a streak sweep range timing chart. This monitor light detection device 2
Reference numeral 8 denotes a monitor light 14 at a predetermined time synchronized with the excitation light generation time based on the detection signal output from the control device 27.
Of the light intensity is detected, and the result is output to the input unit of the display device 29. For example, when the optical functional dye α in the optical recording medium 26 is benzyl, the detection timing of the monitor 14 in the monitor light detection device 28 is about 5 μs after excitation.

The pulse width of the monitor light 14 is the optical functional dye α.
If it is shorter than the lifetime of the excited state of the
An ordinary photodetector such as a photodiode is used as the light source, and the timing controller 23 adjusts the generation timing of the monitor light 14 to receive the light. When the pulse width of the monitor light 14 is longer than the lifetime of the photofunctional dye α in the excited state, or when the monitor light 14 is continuous light, the monitor light detector 28 is used.
As the streak camera, a monitor light 14 is time-resolved and measured and received.

In this monitor light detecting device 28, when the monitor light 14 passes through the unrecorded portion 32 of the optical functional film 3, the change in light intensity based on the transient absorption characteristic of the light component of the predetermined wavelength λ ₄ is measured. However, when the monitor light 14 passes through the recording unit 31 of the optical functional film 3, almost no change in light intensity is measured. The display device 29 stores the electric signal output from the monitor light detection device 28 in its memory unit as pixel data in synchronization with the scanning signal for the stage.

Next, the stage on which the optical recording medium 26 is installed, based on the scanning signal output from the control device 27, at a predetermined time synchronized with the excitation light generation time, the monitor light 1
It moves in a plane with respect to the chief ray of 4. By this stage scanning, the optical recording medium 26 is two-dimensionally scanned with each spot of the optical functional film 3 by the spot of the monitor light 14.

By repeating the above operation, the monitor light detection device 28 detects the light intensity of the monitor light 14 in accordance with the arrangement of the recorded portions 31 and the unrecorded portions 32 in the optical functional film 3, and the optical recording is performed. The predetermined information recorded on the optical functional film 3 of the medium 26 is reproduced on the display unit of the display device 29.

When the monitor light detection device 28 is a streak camera and the bandpass filter 27 is a spectroscope for wavelength-splitting in the slit axis direction of the streak camera, the optical functional films 3 of the optical recording medium 26 are mutually protected. By doping a plurality of photofunctional dyes having different light transient absorption characteristics, the recorded predetermined information is two-dimensionally analyzed and reproduced with respect to the transient absorption wavelength and time profile.

FIGS. 6B and 6C show the recording / reproducing method of the second embodiment of the optical recording medium of the present invention. First, a reproducing method of wavelength multiplexing recording will be described.

Based on the light emission signal output from the control device 27, the excitation light generator 22 emits the excitation light 13 from its light emitting portion at a predetermined time. The excitation light 13 has a predetermined wavelength λ ₃ included in the optical absorption bands of the optical functional dyes α and β doped in the optical functional films 3 and 5 of the optical recording medium 26, respectively. For example, when the optical functional dyes α and β are respectively benzyl and benzophenone in the optical recording medium 26 in which wavelength multiplexing is recorded, the wavelength of the excitation light 13 is 355 nm.

Next, the excitation light 13 is reflected by the mirrors 25a and 25a.
The light is reflected by b and is incident on a region of the optical recording medium 26 including a predetermined position on the protective film 6. The excitation light 13 is applied to the protective film 6
Through the protective film 4 and is partially absorbed by the optical functional film 5. Further, the excitation light 13 is partially absorbed by the optical functional film 3, transmitted through the ultraviolet light absorption film 2 and the substrate 1, and almost absorbed by the bandpass filter 27. The photo-functional dyes α and β, which are respectively doped in the photo-functional films 3 and 5 which have absorbed the excitation light 13, are highly efficiently transited to a metastable excited singlet state or excited triplet state, and are degassed. The excitation life is maintained for several tens of μs and the state returns to the steady state. For example, when the photofunctional dyes α and β are benzyl and benzophenone, respectively, they both transit to the excited triplet state with high efficiency. The excitation lifetime of the photofunctional dyes α and β is greatly affected by oxygen in the atmosphere.

Next, based on the light emission signal output from the control device 27, the monitor light generator 21 emits the monitor light 14 from the light emitting portion at a predetermined time synchronized with the excitation light generation time. When the optical functional dyes α and β are wavelength-multiplexed recorded on the optical recording medium 26, the pulse width is the optical functional dye α and β.
The monitor light 14 shorter than the excitation lifetime of β is generated at the time when the maximum absorbance of the photofunctional dyes α and β is reached. Further, when the pulse width is longer than the excitation lifetime of the photofunctional dyes α and β, or the monitor light 14 which is continuous light, the generation time of the excitation light 13 and the maximum absorbance arrival time of the photofunctional dyes α and β are determined. It is generated in a predetermined range including.

The monitor light 14 is condensed by the convex lens 24a to form a spot at a predetermined position on the protective film 4 of the optical recording medium 26, and the protective film 4, the optical functional film 3, the ultraviolet light absorbing film 2 and The substrate 1 is sequentially transmitted.

However, the monitor light 14 incident on the unrecorded portion 52 of the optical functional film 5 is in the optical transient absorption wavelength band of the optical functional dye β when the optical functional dye β is in the transition to the excited state. The contained optical component of the predetermined wavelength λ ₅ is absorbed. On the other hand, the monitor light 14 that has entered the recording portion 51 of the optical functional film 5 passes through the optical functional film 5 without absorbing the optical component of the predetermined wavelength λ ₅ . Similarly, the monitor light 14 that has entered the unrecorded portion 32 of the optical functional film 3 has a predetermined wavelength included in the transient absorption wavelength band of the optical functional dye α when the optical functional dye α is transitioning to the excited state. The light component of wavelength λ ₄ is absorbed. On the other hand, the monitor light 14 that has entered the recording portion 31 of the optical functional film 3 has a predetermined wavelength λ.
The light component of ₄ is not absorbed and passes through the optical functional film 3.

Next, the monitor light 14 that has passed through the optical recording medium 26 passes through a bandpass filter 27 whose center wavelength is a predetermined wavelength λ ₄ included in the transient absorption wavelength band of the optical functional dye α. With this bandpass filter 27, monitor light 1
4 absorbs light components other than the predetermined wavelength λ ₄ . For example, when the optical functional dye α in the optical recording medium 26 is benzyl, the center wavelength of the bandpass filter 27 is 480n.
It should be m. The monitor light 14 has a convex lens 24a.
And is received by the light receiving unit of the monitor light detection device 28.

The monitor light detection device 28 is the control device 2
The light intensity of the monitor light 14 is detected at a predetermined time synchronized with the excitation light generation time on the basis of the detection signal output from the monitor 7, and the result is output to the input unit of the display device 29. For example, when the optical functional dyes α and β in the optical recording medium 26 are benzyl and benzophenone, respectively, the detection time of the monitor 14 in the monitor light detection device 28 is 1 to 5 μm after excitation.
s has elapsed.

The pulse width of the monitor light 14 is the optical functional dye α.
If it is shorter than the lifetime of the excited state of the
An ordinary photodetector such as a photodiode is used as the light source, and the timing controller 23 adjusts the generation timing of the monitor light 14 to receive the light. When the pulse width of the monitor light 14 is longer than the lifetime of the photofunctional dye α in the excited state, or when the monitor light 14 is continuous light, the monitor light detector 28 is used.
As the streak camera, a monitor light 14 is time-resolved and measured and received.

In the monitor light detector 28, the monitor light 14
When the light passes through the non-deteriorated portion 32 of the optical functional film 3, the change in the light intensity based on the transient absorption characteristic of the light component of the predetermined wavelength λ ₄ is measured, but the monitor light 14 causes the optical deterioration of the optical functional film 3. Part 3
When passing 1, the change in light intensity is hardly measured. The display device 29 stores the electric signal output from the monitor light detection device 28 in its memory unit as pixel data in synchronization with the scanning signal for the stage.

Next, the bandpass filter 27 is replaced with a filter whose central wavelength is the predetermined wavelength λ ₅ included in the optical transient absorption wavelength band of the optical functional dye β, and the above operation is repeated. For example, when the optical functional dye β in the optical recording medium 26 is benzophenone, the center wavelength of the bandpass filter 27 may be 520 nm.

In the monitor light detector 28, the monitor light 14
When the light passes through the non-deteriorated portion 52 of the optical functional film 5, the change in the light intensity of the light component of the predetermined wavelength λ ₅ is measured, but the monitor light 14 passes through the light deteriorated portion 51 of the optical functional film 5. In this case, the change in light intensity is hardly measured. In addition, the display device 29
Stores the electric signal output from the monitor light detection device 28 in the memory unit as pixel data in synchronization with the scanning signal for the stage.

Next, the stage on which the optical recording medium 26 is installed, based on the scanning signal output from the control device 27, at a predetermined time synchronized with the excitation light generation time, the monitor light 1
It moves in a plane with respect to the chief ray of 4. By this stage scanning, the optical recording medium 26 is two-dimensionally scanned with each spot of the optical functional film 3 by the spot of the monitor light 14.

By repeating the above operation, in the monitor light detection device 28, the light intensity of the monitor light 14 is arranged in the recording portion 31 and the unrecorded portion 32 in the optical functional film 3 and the recording in the optical functional film 5. The optical functional films 3, 5 of the optical recording medium 26, which are detected corresponding to the arrangement of the portions 51 and the unrecorded portions 52,
The first and second information recorded on the display device 29 is reproduced on the display part of the display device 29.

Next, a reproducing method of time multiplex recording will be described.

First, based on the light emission signal output from the control device 27, the excitation light generator 22 emits the excitation light 13 from its light emitting portion at a predetermined time. This excitation light 13 is
It has a predetermined wavelength λ ₃ included in the optical absorption bands of the optical functional dyes α and β doped in the optical functional films 3 and 5 of the optical recording medium 26, respectively. For example, when the optical functional dyes α and β are respectively anthracene and benzophenone in the time-divisionally recorded optical recording medium 26, the wavelength of the excitation light 13 is 3
55 nm.

Next, the excitation light 13 is reflected by the mirrors 25a and 25a.
The light is reflected by b and is incident on a region of the optical recording medium 26 including a predetermined position on the protective film 6. The excitation light 13 is applied to the protective film 6
Through the protective film 4 and is partially absorbed by the optical functional film 5. Further, the excitation light 13 is partially absorbed by the optical functional film 3, transmitted through the ultraviolet light absorption film 2 and the substrate 1, and almost absorbed by the bandpass filter 27. The photo-functional dyes α and β, which are respectively doped in the photo-functional films 3 and 5 which have absorbed the excitation light 13, are highly efficiently transited to a metastable excited singlet state or excited triplet state, and are degassed. The excited state life is maintained for several tens of μs and the state returns to the steady state. For example, when the photofunctional dyes α and β are anthracene and benzophenone, respectively, they are highly efficiently transited to an excited singlet state and an excited triplet state, respectively. The lifetime of the photofunctional dyes α and β in the excited state is greatly affected by oxygen in the atmosphere.

Next, based on the light emission signal output from the control device 27, the monitor light generator 21 emits the monitor light 14 from its light emitting portion at a predetermined time synchronized with the excitation light generation time.

FIG. 10 shows a second embodiment of the optical recording medium of the present invention.
A reproducing method for time-multiplexed recording of the embodiment is shown (a)
Is a graph of changes in light transient absorption time, and (b) is a timing chart of excitation light generation and monitor light generation. When the optical functional dyes α and β are time-multiplexed recorded on the optical recording medium 26, the monitor light 14 having a pulse width shorter than the lifetime of the excited state of the optical functional dyes α and β is excited by the excitation light at time τ _1. 1
3 is emitted, and the monitor light 14 is emitted at times τ ₂ and τ ₃ , which are the maximum absorbance arrival times of the photofunctional dyes α and β. When the pulse width is longer than the lifetime of the photofunctional dyes α and β in the excited state, or when the monitor light 14 is continuous light, the excitation light 13 is emitted at time τ ₁ and the photofunctional dyes α and β are emitted. The monitor light 14 is detected by the monitor light detecting device 28 at times τ ₂ and τ ₃ , which are the times when the maximum absorbance is reached.

The monitor light 14 is condensed by the convex lens 24a to form a spot at a predetermined position on the protective film 4 of the optical recording medium 26, and the protective film 4, the optical functional film 3, the ultraviolet light absorbing film 2 and The substrate 1 is sequentially transmitted.

However, the monitor light 14 that has entered the unrecorded portion 52 of the optical functional film 5 is in the optical transient absorption wavelength band of the optical functional dye β when the optical functional dye β is in the excited state. The contained optical component of the predetermined wavelength λ ₅ is absorbed. On the other hand, the monitor light 14 that has entered the recording portion 51 of the optical functional film 5 passes through the optical functional film 5 without absorbing the optical component of the predetermined wavelength λ ₅ . Similarly, the monitor light 14 that has entered the unrecorded portion 32 of the optical functional film 3 is included in the optical transient absorption wavelength band of the optical functional dye α when the optical functional dye α is transitioning to the excited state. The light component of the predetermined wavelength λ ₄ is absorbed. On the other hand, the monitor light 14 that has entered the recording portion 31 of the optical functional film 3 passes through the optical functional film 3 without absorbing the optical component of the predetermined wavelength λ ₄ .

Next, the monitor light 14 that has passed through the optical recording medium 26 has a bandpass filter 27 whose center wavelength is a predetermined wavelength λ ₄ included in the optical transient absorption wavelength band of the optical functional dye α.
Pass through. The bandpass filter 27 absorbs the optical components other than the predetermined wavelength λ ₄ in the monitor light 14. For example, when the optical functional dyes α and β in the optical recording medium 26 are anthracene and benzophenone, respectively, the center wavelength of the bandpass filter 27 may be 520 nm. The monitor light 14 is condensed by the convex lens 24 a and received by the light receiving section of the monitor light detecting device 28.

The monitor light detection device 28 is the control device 2
The light intensity of the monitor light 14 is detected at a predetermined time synchronized with the excitation light generation time on the basis of the detection signal output from the monitor 7, and the result is output to the input unit of the display device 29. For example, when the optical functional dyes α and β in the optical recording medium 26 are anthracene and benzophenone, respectively, the detection time of the monitor 14 in the monitor light detection device 28 is 5 n after excitation.
The time is about s and the time is 1 to 5 μs.

The pulse width of the monitor light 14 is the optical functional dye α.
If it is shorter than the lifetime of the excited state of the
An ordinary photodetector such as a photodiode is used as the light source, and the timing controller 23 adjusts the generation timing of the monitor light 14 to receive the light. When the pulse width of the monitor light 14 is longer than the excitation life of the optical functional dye α, or when it is continuous light, a streak camera or the like is used as the monitor light detection device 28 to measure the monitor light 14 in a time-resolved manner. And receive light.

In the monitor light detecting device 28, when the monitor light 14 passes through the non-deteriorated portion 32 of the optical functional film 3, the change in light intensity based on the transient absorption characteristic of the light component of the predetermined wavelength λ ₄ is measured. However, when the monitor light 14 passes through the light deterioration portion 31 of the optical functional film 3, almost no change in light intensity is measured. The display device 29 stores the electric signal output from the monitor light detection device 28 in its memory unit as pixel data in synchronization with the scanning signal for the stage.

Next, the stage on which the optical recording medium 26 is installed, based on the scanning signal output from the control device 27, at a predetermined time synchronized with the excitation light generation time, the monitor light 1
It moves in a plane with respect to the chief ray of 4. By this stage scanning, the optical recording medium 26 is two-dimensionally scanned with each spot of the optical functional film 3 by the spot of the monitor light 14.

By repeating the above operation, in the monitor light detection device 28, the light intensity of the monitor light 14 is arranged in the recording portion 31 and the unrecorded portion 32 in the optical functional film 3 and the recording in the optical functional film 5. The optical functional films 3, 5 of the optical recording medium 26, which are detected corresponding to the arrangement of the portions 51 and the unrecorded portions 52,
The first and second information recorded on the display device 29 is reproduced on the display part of the display device 29.

FIG. 11 shows a second embodiment of the optical recording medium of the present invention.
The reproduction result for the time multiplex recording of the embodiment is shown, (a)
When the photofunctional dyes α and β are both photo-deteriorated,
(B) is the case where only the photo-functional dye β is photo-deteriorated,
(C) is the case where only the photo-functional dye α is photo-deteriorated,
(D) is a case where both the optical functional dyes α and β are non-deteriorated. Here, the photofunctional dyes α and β are anthracene and benzophenone, respectively, and a streak camera is used as the monitor photodetector 28. That is, FIG.
4A and 4B are reproduction results for the regions F, C, D, and E in FIG. 4B. In the photofunctional dyes α and β, the full width at half maximum of light transient absorption is 5 ns and 2 μm, respectively. According to these, the photo-functional films 3 of the photo-functional dyes α and β that are not photo-degraded,
It can be seen that predetermined information is reproduced corresponding to the distribution in FIG.

The present invention is not limited to the above embodiments, but various modifications can be made.

For example, in the second embodiment of the optical recording medium, the optical functional film has two layers, but the optical functional films having mutually different optical transient absorption characteristics may be multilayered by the same method. Thereby, the multiplicity of recorded information can be improved.

Further, in the above-mentioned various examples of the optical recording medium, the photo-functional dye is said to cause photodegradation upon irradiation with ultraviolet rays, but even if photo-isomerization occurs due to irradiation with ultraviolet rays, the same action and effect can be obtained.

Furthermore, in the above embodiment of the optical recording / reproducing apparatus, when a streak camera combined with a spectroscope is used as the monitor light detecting apparatus, one-point information of the optical recording medium is reproduced as two-dimensional information by stage scanning. on the other hand,
When a gate II having a gate function, a two-dimensional image pickup tube such as a framing camera, and a bandpass filter are used, the timings of the filter and the gate are sequentially controlled so that the layered optical functional film of the optical recording medium has a specific wavelength. And the two-dimensional information recorded limited to the area of the specific time is reproduced at once.

[0096]

As described above in detail, according to the present invention, the optical functional film formed on the substrate is irradiated with ultraviolet light in a distribution corresponding to predetermined information, and thus the distribution is dealt with. As a result, a recorded portion in which the light transient absorption characteristic disappears and an unrecorded portion in which the light transient absorption characteristic is retained are formed. Therefore, predetermined information is recorded as a two-dimensional array of recording units in the optical functional film. Furthermore, after irradiating the optical functional film with light of a predetermined wavelength, the predetermined light is irradiated at a timing corresponding to the time profile of the optical transient absorption characteristics in the unrecorded portion, and the light that has passed through each position of the optical functional film. By performing time-resolved measurement of, the predetermined information is reproduced corresponding to the detection of the light intensity in the predetermined wavelength band. Therefore, there is an effect that information can be held so that it can be reproduced only by a method that keeps confidentiality.

Further, according to the present invention, by irradiating the optical functional film formed on the substrate with ultraviolet light in a distribution corresponding to predetermined information, the optical transient absorption characteristic disappears corresponding to the distribution. The recorded portion and the unrecorded portion that retains the light transient absorption characteristics are formed. Therefore, predetermined information is recorded as a two-dimensional array of photo-deteriorated portions in the optical functional film. A protective film and an optical functional film are sequentially formed on this optical functional film,
By repeating the above operation, the predetermined plurality of pieces of information are recorded as a three-dimensional array of the recording portions in each optical functional film. Therefore, there is an effect that information can be held with high multiplicity.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical recording medium according to an embodiment of the present invention, in which (a) is a first embodiment and (b) is a second embodiment.

FIG. 2 is a process cross-sectional view showing the optical recording method of the first embodiment of the optical recording medium of the present invention.

FIG. 3 is a process sectional view showing an optical recording method of a second embodiment of the optical recording medium of the present invention.

FIG. 4 is a plan view showing a recording state of an embodiment of the optical recording medium of the present invention, (a) is a first embodiment and (b) is a second embodiment.

FIG. 5 is an explanatory diagram showing the configuration of an embodiment of an optical recording / reproducing apparatus of the present invention.

FIG. 6 shows a recording / reproducing method for an optical recording medium of the present invention, wherein (a) is a process sectional view of a first embodiment, and (b) and (c) are process sectional views of a second embodiment.

FIG. 7 is a graph showing a result of measuring an absorption spectrum of an optical functional film in a steady state.

FIG. 8 shows the results of measurement of transient absorption characteristics of an optical functional film, (a) shows an absorption spectrum at 3 μs after excitation,
(B) is a graph of a time profile of absorbance in a wavelength band of 450 to 510 nm.

9A and 9B show the recording / reproducing method of the first embodiment of the optical recording medium of the present invention, where FIG. 9A is a monitor light pulse, FIG. 9B is an excitation light pulse, and FIG. 9C is a streak sweep range timing chart. Is.

FIG. 10 shows a reproducing method for time-multiplexed recording of a second embodiment of the optical recording medium of the present invention, (a) is a graph of transient absorption time change, (b) is excitation light generation and monitor. It is a timing chart of light generation.

FIG. 11 shows the reproduction result for time-division recording of the second embodiment of the optical recording medium of the present invention. (A) shows the case where both the optical functional dyes α and β are photo-deteriorated, and (b) shows the same. When only the photo-functional dye β is photo-deteriorated, (c) is the photo-functional dye α only is photo-degraded, and (d) is the photo-functional dye α and β both are non-deteriorated. Is a graph of.

[Explanation of symbols]

1 ... Substrate, 2 ... Ultraviolet light absorbing film, 3, 5 ... Optical functional film,
4, 6 ... Protective film, 7, 8 ... Mask, 11, 12 ... Ultraviolet light, 13 ... Excitation light, 14, 15 ... Monitor light, 21 ... Monitor light generator, 22 ... Excitation light generator, 23 ... Control device , 24 ... Convex lens, 25 ... Mirror, 26 ... Optical recording medium, 27 ... Bandpass filter, 28 ... Monitor light detecting device, 29 ... Display device, 31, 51 ... Recording unit, 32, 52
... Unrecorded area, 71, 81 ... Unmasked area, 72, 82 ... Masked area.

Claims (4)

[Claims] 1. An optical recording medium comprising a substrate and an optical functional film formed on the substrate, wherein the optical functional film is an excited state that transits transiently by irradiation with light of a first wavelength. Has optical transient absorption characteristics at
An optical recording medium characterized in that a recording portion which has lost the light transient absorption characteristic by irradiation with light of a second wavelength and an unrecorded portion which holds the light transient absorption characteristic are arranged in correspondence with predetermined information. . 2. An optical recording medium comprising a substrate and a plurality of optical functional films and protective films which are sequentially laminated on the substrate, wherein the optical functional film has a first wavelength. The recording section has optical transient absorption characteristics which are different from each other in the excited state which transits transiently by the light irradiation, and the recording section which has lost the optical transient absorption characteristics by the light irradiation of the second wavelength and the optical transient absorption characteristics. The held unrecorded areas are arranged corresponding to predetermined information, and the protective film has a light absorption characteristic of absorbing the light of the second wavelength, or an oxygen supply to the optical functional film. An optical recording medium characterized by controlling each of them. 3. The optical recording according to claim 1, wherein the recording portion has lost the optical transient absorption characteristic due to photodegradation in which the light of the second wavelength and oxygen react. Medium. 4. The optical recording medium according to claim 2, wherein the optical functional films have optical transient absorption characteristics in which absorption wavelength bands or time profiles are different from each other.