JP3434321B2 - Optical recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photon mode optical memory.
Recording mediumBodyIt relates to the optical recording method used. [0002] 2. Description of the Related Art In recent years, for the next generation optical recording technology,
Light using photochromic materials that react in ton mode
Recording technology is being actively studied. Used for optical recording media
Photochromic materials include, for example, Terao et al.
"Basics of Optical Memory" 92-97, p. 129-13
1 (issued by Corona, 1990)
Na, spiropyran, azobenzene, fulgide, diary
Many photochromic compounds such as luetene are known.
ing. [0003] The smell of such photochromic compounds
Photochromic reactions commonly known as
The chromic compound molecule itself absorbs light of a specific wavelength and
The molecular structure changes, and the absorption
This is a reaction in which optical characteristics such as a vector and a refractive index change. FIG. 2 shows such a photochromic reaction.
And a photochromic having a molecular structure A
Compound molecule has specific wavelength λ₁Absorbs the light of
Change. Photochromic of changed molecular structure B
Compound molecules have different wavelengths λ_TwoTo light or heat (ΔH)
Thus, the state of the same structure A can be returned again. Follow
And the specific wavelength λ₁Or λ_TwoLight for recording or erasing
And use it to detect changes in the absorption spectrum, refractive index, etc.
Using the light that can be emitted as light for reproduction
More rewritable optical recording media can be configured
You. The following chemical formula represents a typical spiropyran-based
Photochromic reaction of photochromic material
3 is a chemical formula showing a change in molecular structure. [0006] Embedded image FIG. 3 shows the absorption due to the change in the molecular structure.
It is a figure which shows the change of a collection spectrum. As shown in Figure 3
As shown, the spectrum (1) before the light irradiation has a wavelength of 350 nm.
The molecular structure changes as shown in the above formula by long light irradiation
Then, the spectrum changes to spectrum (2). This
500 nm light irradiation on the molecules of the molecular structure after the change of
By applying heat, part of it returns to its original molecular structure.
And the spectrum changes to (3). The following chemical formula represents a typical diaryl ether
Of the molecular structure associated with the photochromic reaction of
It is a chemical formula showing a change. [0009] Embedded image FIG. 4 shows the components of the diarylethene-based material.
Showing the change in the absorption spectrum with the change in the child structure
It is. As shown in FIG. 4, the spectrum of the ring-opened product (1)
Changes to a closed-ring spectrum (2), and is close to 600 nm.
It has a characteristic absorption nearby. [0011] SUMMARY OF THE INVENTION
Optical recording using photochromic compounds
In order to use the medium at a high transfer rate,
Need to be raised as much as possible. Also, the light used for recording
When it is not possible to obtain sufficient power for strength
However, increasing the recording sensitivity to a practical recording speed
Can respond. [0012] By the way, a conventionally generally recognized file.
The photochromic reaction, as shown in FIG.
Photochromic compound molecules absorb light (photons)
The mechanism that causes the photochromic reaction
This is called a “single-molecule process” mechanism). The inventor
Et al., The 53rd JSAP Academic Lecture (Autumn 1992)
Season) In 17a-T-9, the recording sensitivity is
Extinction coefficient ε (l / mol · cm) and the amount of reaction
Is proportional to the product ε · k with the particle yield k (recording sensitivity is J / cm
^TwoIs inversely proportional when represented by).
Therefore, the larger the ε · k, the higher the recording sensitivity
It can be said that the quantum yield k originally indicates the probability
And cannot exceed the maximum value of 1. Also molecular absorption
It is also difficult to design molecules to make the optical coefficient ε extremely large.
And even if it can, the quantum yield will decrease
Problem arises. Therefore, conventional photochromic
It is easy to increase the recording sensitivity using
There was no. The object of the present invention is to provide
New photons that can significantly increase recording sensitivity
modeLight ofIt is to provide a recording method. [0014] Means for Solving the Problems The present inventors have solved the above problems.
As a result of intensive studies to solve the problem
Light containing photochromic compound molecules as body molecules
The presence of energy donor molecules in the recording medium
Recording sensitivity can be significantly increased by
Ming has been completed. [0015] [0016] [0017] [0018] The optical recording method of the present invention comprises:Energy donor
Diarylethene-based photochromic compound acting as a catalyst
Ring-opening molecule and the above-mentioned dia acting as an energy acceptor
Ring-closing molecule of Lielethene photochromic compound
Optical recording media containing both ring-opening molecules and ring-closing molecules
Irradiates light of a wavelength that has absorption as recording light, and
Set the ring molecule to the excited state and close from the open ring molecule in the excited state.
Ring closure by transferring energy to ring molecules
Causing a ring-opening reaction in the body moleculeIt is especially important to enter the recording state.
It is a sign. In addition, the optical recording method of the present invention simply employs “information
Recording is not limited to
Applicable to "erasing information" recorded on the body
It is. [0021] FIG. 1 shows an optical recording medium and an optical recording method according to the present invention.
It is a figure which shows the operation | movement in FIG. In FIG. 1, A
And B show the molecular structure of the energy acceptor molecule
And C represents an energy donor molecule. According to the present invention, as shown in FIG.
The energy donor molecule C has a specific wavelength λ_TwoAbsorb light
To an excited state, and the energy acceptor component of the molecular structure B
Provide energy to the child. Thereby, the molecular structure B
The energy acceptor molecule changes to the state of molecular structure A
It will be in the recording state. Further, as shown in FIG.
When the concentration of the body molecule C becomes relatively large, the molecular structure B
The probability of energy transfer to the energy acceptor molecule is
Increases the recording sensitivity.
You. Further, an energy acceptor molecule having a molecular structure B
Is the specific wavelength λ_TwoIf you have sensitivity to the light of, for example
Energy acceptor molecule is a photochromic compound
In such a case, as shown in FIG.
A photochromic reaction occurs. Therefore, such a place
In this case, the photochromic reaction of one molecule process
But the presence of the energy donor molecule C
1 (a) or 1 (b).
Will be present, and the conventional one-molecule process photo
Significantly improve recording sensitivity over chromic reactions
Can be. [0025] [Explanation of the embodiment]Example 1 First, the diarylethene-based photoreactor shown in the above (Chemical Formula 2)
The sensitivity in a solvent was measured using a rhomic compound. This
The ring-opened form of the photochromic compound shown in FIG.
As shown in Fig. 1 (1), there is absorption at 400 to 520 nm.
It is closed by irradiating light of the wavelength in this region.
A ring reaction occurs, and the absorption spectrum is
Torr (2). In addition, there is absorption only in the closed form 5
Irradiate light in the wavelength range of 20 to 700 nm to the closed ring
When the ring-opening reaction, which is the reverse reaction,
The spectrum changes from the vector (2) to the absorption spectrum (1). Obedience
Thus, for example, wavelengths of 458 nm, 488 nm, 515 nm
Irradiation of Ar laser light such as
Ring opening reaction by irradiating HeNe laser beam of 633 nm long
By doing so, optical recording can be performed. First, the molecules of the photochromic compound
To find the product of the extinction coefficient ε and the quantum yield k, the irradiation time t
And the relationship between absorbance A were plotted. Photochromic
The product ε · k, which represents the sensitivity of the compound, is the slope of such a plot.
Can be found from the beginning. FIG. 5 shows the photochromium shown in the above (Chemical Formula 2).
Light of wavelength λ = 633nm to benzene solution
Absorption at λ = 600 nm upon irradiation and ring opening reaction
The change in luminous intensity A (corresponding to the ring-closure concentration) was plotted.
FIG. The vertical axis is -lnA, and the horizontal axis is the irradiation time t.
(S). As shown in FIG. 5, the graph is linear.
Ε · k, which is an index indicating the reaction sensitivity, is constant.
Forms a closed form by a photochromic reaction in one molecule process
It indicates that. From the slope of this graph,
k = 1700 (l / mol · cm) is obtained. The wavelength λ is 458 nm, 488 nm, 515
Similarly, when performing a ring closure reaction with light such as nm,
You can ask. At this time, the vertical axis is -ln (A (t)
−A (∞)). This is such a wavelength
In the region, not only the open ring but also the closed ring has absorption
In the ring closure reaction, the reverse reaction also proceeds at the same time.
In the light steady state after the light irradiation has been performed for a sufficiently long time.
Indicates that the closed and open ring are mixed at a certain ratio.
ing. In FIG. 4, the state of (2) is changed to a closed body.
Although described as corresponding, strictly speaking, ring-closure and ring-opening
The body is in a mixed state. Therefore, in such a case,
The apparent ε · k of the ring closure reaction is
is the sum of ε · k, and this apparent ε · k is λ
= Photo-steady state, similar to ring-opening reaction at 633 nm
The wavelength corresponds to the reciprocal of the
Can be interpreted as an index representing the recording sensitivity in
You. Next, the photochromic compound is
Photochromic in thin film state contained in thin film
The recording sensitivity of the compound was measured. FIG. 6 shows the above diaryl
Ethene-based photochromic compound is converted to polyvinyl butyral
(PVB) resin at a dilute concentration of about 1% by weight
For the formed thin film, the index of the recording sensitivity is
The relationship between the irradiation time t and -lnA to find ε · k
Is a graph in which is plotted. The thin film used for the measurement was P
This photochromic compound is placed in a benzene solution of VB resin.
And then irradiate it sufficiently with blue light beforehand,
To be sure, after the photo-steady state,
It is a thing. Irradiate this thin film with light of λ = 633 nm
This caused a ring opening reaction. As shown in FIG. 6, the slope of the plot is
It is a straight line, and photochromic
This indicates that a reaction has occurred. Plot slope
From this, ε · k as an index of recording sensitivity is 1500 (l /
mol.cm). The photochromic reaction in a polymer medium is
In response, depending on experimental conditions such as environmental temperature,
Swelled upwards instead of a straight line plot as shown
It may be curved. The reason for this is that
Of quantum yield due to differences in environment of photochromic molecules in water
The idea of scatter is proposed, but photochromic
The reaction itself is still a one-molecule process. this
In some cases, the measured response sensitivity gradually decreases over time.
You. The above photochromic in PVB resin
The same measurement was performed with a high concentration of 30% by weight of the compound.
As a result, the plot became linear as in FIG.
You can see that the photochromic reaction occurs in the child process
Was. From the above points, the wave having only the closed-ring form has absorption.
In the case of a ring-opening reaction with long light,
Lomic reaction has occurred. Figure 7 shows the above photochromic
Material is contained in PVB resin at a dilute concentration of 1% by weight.
For a thin film, both the closed and open ring have absorption.
Wavelength, ie, λ = 515 nm, and
The figure which shows the relationship between irradiation time t and -InA at the time of making a ring reaction.
It is. As is clear from FIG. 7, the slope of the plot is straight.
Linear, photochromic reaction also in one molecule process
You can see that is happening. The value of ε · k is 130
0 (l / mol · cm). FIG. 8 shows the same photochromic material as described above.
Thin film of PVB resin containing high concentration of 30% by weight
As in the case of FIG. 7, the light is opened by irradiating light of λ = 515 nm.
The relationship between the irradiation time t and -InA during the ring reaction is shown.
FIG. In this case, as shown in FIG.
Indicates the progress of the reaction
It can also be seen that the reaction sensitivity has been improved. Responsive
Initially, ε · k = 1300 (l / mol · cm)
In some cases, at the later stage of the reaction (t = 300 (s)), ε ·
k = 10000 (l / mol · cm), which is about 7.7
The reaction sensitivity is improved twice. This is because of the opening of the photochromic compound.
The ring molecule becomes the energy donor according to the present invention, and λ =
515 nm light is absorbed to be in an excited state.
Ring-opening reaction of ring-closure by transfer of ghee to ring-closure
Is based on progress. This mechanism is described as follows.
Can be. [0037] Embedded image As described above, in this series of reactions,
Indicates that the ring-opened molecule of the photochromic compound molecule is energy
The ring-opened molecule absorbs light of a specific wavelength.
To the excited state, and the energy is
Transfer to a closed-ring molecule that is an energy acceptor molecule.
This causes a ring-opening reaction of the ring-closed molecule. FIG. 9 shows the photochromic compound as a seed.
Similarly, for the PVB thin film changed to various concentrations, λ =
Irradiate light of 515 nm, and ε · k which is an index of reaction sensitivity
Is plotted on the abscissa of ring-opening body concentration (mol / l).
It is a thing. Total concentration of photochromic compound (ring opening
0.040 (mol / l)
Then, ε · k is constant at 1300 (l / mol · cm)
However, at higher concentrations, ε · k tends to increase.
Direction was recognized. In FIG. 9, the arrow indicates the progress of the reaction.
Indicates the row direction. As is apparent from FIG.
At the initial concentration of the reaction is 1300 (l / m
ol · cm), but in the later stage of the reaction
ε · k has increased, especially for higher concentrations.
There was a tendency for the size to increase. This is energy
Ring-opening, which is an energy donor, increases late in the reaction and
Energy donors at closer distances to closed rings with higher concentrations
Energy transfer occurs due to the presence of
This is due to easy stiffness. Further, as shown in FIG.
Even if the degree is the same, if the reaction sensitivity ε
There is a case. For example, at a ring-opened form concentration of 1 mol / l,
The total concentration of the photochromic compound is 1.13 (mol /
l) and 1.85 (mol / l)
Have different ε · k. This depends on the ring-opening concentration and
This is probably due to the difference in the ratio of the concentration of the ring-closure form. FIG. 10 shows the photochromic compound molecule.
Energy from energy donors when total concentration is relatively low
FIG. 11 schematically shows the movement of the energy, and FIG.
Energy when the total concentration of mic compound molecules is relatively high
The movement is schematically shown. 10 and 11
○ indicates a ring-opened body, and ● indicates a closed-ring body.
You. As shown in FIG.
When the total concentration of nucleophiles is low, the
The concentration is significantly lower than the closed-ring concentration,
Energy is transferred from many ring-opened to closed-ring
You. As a result, ε · k showing the apparent reaction sensitivity is very
It will be a large value. On the other hand, as shown in FIG.
When the total concentration of the tochromic compound molecule is relatively high
Is relatively much higher, even at the same ring-opening concentration.
A closed ring exists and the energy transfer to the closed
The movement is not as concentrated as in the case of the low concentration shown in FIG.
Therefore, the apparent reaction sensitivity ε · k is so large.
Not a value. In the above experiment, λ = 515 nm
Light is illuminated, but both the open and closed forms have absorption.
Light of another wavelength may be used as long as the light has a certain wavelength. FIG.
Is the light when the ring-opening reaction is performed by irradiating light of λ = 458 nm.
FIG. 4 is a diagram showing a relationship between irradiation time t and -lnA. FIG.
As is clear from FIG. 2, the same tendency is observed in this case.
Is recognized, and the ring-opened product as an energy donor
Energy transfer to the ring receptor
A ring opening reaction of the ring is occurring. [0045]Example 2 A diarylethene-based photochromic compound represented by the following chemical formula (4)
The reaction sensitivity was measured in the same manner as in Example 1 using the
Specified. [0046] Embedded image FIG. 13 shows the above-mentioned diarylethene-based resin.
The absorption spectrum of the tochromic material is shown.
Indicates an absorption spectrum in a ring-closed state.
2 shows an absorption spectrum in a ring-opened state. The diarylethene photochromic
High concentration of 0.6mol / l and low concentration of 0.05mo
1 / l dispersed in polystyrene at two different concentrations to form a thin film
Done. Both ring-closed and ring-opened forms are absorbed by the formed thin film
Irradiation of light with a wavelength of 515 nm having
The reaction sensitivity at the time of this was measured. FIG. 14 shows the reaction feeling measured in this manner.
The abscissa represents the wavelength 6 which is proportional to the ring-closure concentration.
The absorbance at 00 nm is shown. FIG. 14 (a)
It corresponds to a high concentration thin film sample, and FIG.
It supports low concentration thin film samples. Fig. 14 (a)
As is clear from the graph, when the concentration was high, the progress of the reaction (arrow
(In the direction of the mark), the reaction sensitivity is improved about three times. This
This is because the ring-opened product formed as the reaction proceeds
It becomes a donor molecule, and the energy acceptor component
Due to the transfer of energy to the closed ring
it is conceivable that. Similarly, as is apparent from FIG.
In addition, even at low concentrations, the reaction sensitivity increases with the progress of the reaction.
It is rising. However, the remarkable effect of high concentration
It is not an increase in sensitivity. [0051]Example 3 A diarylethene-based photochromic compound shown in the following (Chem. 5)
The reaction sensitivity was measured in the same manner as in Example 1 using the
Specified. [0052] Embedded image FIG. 15 shows the above-mentioned diarylethene-based resin.
The absorption spectrum of the tochromic material is shown.
Indicates an absorption spectrum in a ring-closed state.
2 shows an absorption spectrum in a ring-opened state. The diarylethene photochromic
High concentration of 0.6mol / l and low concentration of 0.05mo
1 / l dispersed in polystyrene at two different concentrations to form a thin film
Done. Both ring-closed and ring-opened forms are absorbed by the formed thin film
Irradiation of light with a wavelength of 515 nm having
The reaction sensitivity at the time of this was measured. FIG. 16 shows the reaction feeling measured in this manner.
The abscissa represents the wavelength 6 which is proportional to the ring-closure concentration.
The absorbance at 00 nm is shown. FIG. 16 (a)
It corresponds to a high concentration thin film sample, and FIG.
It supports low concentration thin film samples. Fig. 16 (a)
As is clear from the graph, when the concentration was high, the progress of the reaction (arrow
The reaction sensitivity has improved about 3 times or more with
You. This is because the ring-opened product formed as the reaction proceeds
Energy from the ring-opened form.
Transfer of energy to the closed molecule
It is considered to be. Similarly, as apparent from FIG.
In addition, even at low concentrations, the reaction sensitivity
It has increased about 1.5 times.Example 4 A diarylethene-based photochromic compound represented by the following (Chem. 6)
The reaction sensitivity was measured in the same manner as in Example 1 using the
Specified. [0057] Embedded image FIG. 17 shows the above-mentioned diarylethene-based resin.
The absorption spectrum of the tochromic material is shown.
Indicates an absorption spectrum in a ring-closed state.
2 shows an absorption spectrum in a ring-opened state. This diarylethene photochromic
High concentration 0.5mol / l and low concentration 0.04mo
1 / l dispersed in polystyrene at two different concentrations to form a thin film
Done. Both ring-closed and ring-opened forms are absorbed by the formed thin film
Irradiates light of wavelength 488 nm having
The reaction sensitivity at the time of this was measured. FIG. 18 shows the reaction feeling measured in this manner.
The abscissa represents the wavelength 6 which is proportional to the ring-closure concentration.
The absorbance at 00 nm is shown. FIG. 18 (a)
It corresponds to a high concentration thin film sample, and FIG.
It supports low concentration thin film samples. Fig. 18 (a)
As is clear from the graph, when the concentration was high, the progress of the reaction (arrow
(In the direction of the mark), the reaction sensitivity is about twice as high.
You. This is because the ring-opened product formed as the reaction proceeds
Energy from the ring-opened form.
Transfer of energy to the closed molecule
It is considered to be. As is apparent from FIG.
In the case of concentration, the reaction sensitivity decreases as the reaction proceeds.
Was. It accepts energy from the energy donor molecule
Energy transfer to body molecules does not contribute much
Is shown. [0062]Example 5 A diarylethene-based photochromic compound represented by the following formula (7)
The reaction sensitivity was measured in the same manner as in Example 1 using the
Specified. [0063] Embedded image FIG. 19 shows the above-mentioned diarylethene-based resin.
The absorption spectrum of the tochromic material is shown.
Indicates an absorption spectrum in a ring-closed state.
2 shows an absorption spectrum in a ring-opened state. This diarylethene-based photochromic
High concentration of 0.5mol / l and low concentration of 0.05mo
1 / l dispersed in polystyrene at two different concentrations to form a thin film
Done. Both ring-closed and ring-opened forms are absorbed by the formed thin film
Irradiates light of wavelength 488 nm having
The reaction sensitivity at the time of this was measured. FIG. 20 shows the reaction feeling measured in this manner.
The abscissa represents the wavelength 6 which is proportional to the ring-closure concentration.
The absorbance at 00 nm is shown. FIG. 20 (a)
It corresponds to a high concentration thin film sample, and FIG.
It supports low concentration thin film samples. As is apparent from FIG.
In the case of high concentration in the examples, even if the reaction proceeds, the reaction sensitivity
Is almost constant. However, generally the matrix
Reaction in a photochromic reaction
Considering that the reaction sensitivity decreases in both cases, the reaction sensitivity
That the energy transfer according to the present invention is constant.
That the improvement in reaction sensitivity due to motion
Conceivable. Also, as shown in FIG.
In the case of low concentration in the examples, as the reaction progresses
The reaction sensitivity decreased. Therefore, the energy according to the present invention
It seems that the improvement of the reaction by the movement did not contribute much.
Will be [0069]Comparative example A diarylethene-based photochromic compound shown in the following (Chem. 8)
The reaction sensitivity was measured in the same manner as in Example 1 using the
Specified. [0070] Embedded image FIG. 21 shows the above-mentioned diarylethene-based resin.
The absorption spectrum of the tochromic material is shown.
Indicates an absorption spectrum in a ring-closed state.
2 shows an absorption spectrum in a ring-opened state. This diarylethene photochromic
High concentration of 0.5mol / l and low concentration of 0.06mo
1 / l dispersed in polystyrene at two different concentrations to form a thin film
Done. Both ring-closed and ring-opened forms are absorbed by the formed thin film
Irradiates light of wavelength 488 nm having
The reaction sensitivity at the time of this was measured. FIG. 22 shows the reaction feeling measured in this manner.
The abscissa represents the wavelength 6 which is proportional to the ring-closure concentration.
The absorbance at 00 nm is shown. FIG. 22 (a)
It corresponds to a high concentration thin film sample, and FIG.
It supports low concentration thin film samples. As shown in FIG.
The diarylethene-based photochromic material shown in 8)
When used, even at high concentrations,
The reaction sensitivity is low. Also shown in FIG.
As shown in the figure, even at low concentrations,
I have. From these results, this diarylethene-based pho
When a tochromic compound is used, the
Improvement of sensitivity by energy transfer hardly contributes
it is considered as. The results of the above Examples 1 to 5 and Comparative Example
Used diarylethene photochromic compound
Considering the product, it is used in Examples 1 to 4.
Photochromic compounds have an asymmetric structure.
The photochromic compounds used in Example 5 and Comparative Example
The object has a symmetric structure. In Example 5, high concentration
Only a small increase in sensitivity due to energy transfer according to the invention.
In the comparative example, even at a high concentration,
No improvement in sensitivity due to energy transfer according to the invention
No. Considering these facts, diarylethene-based
Photochromic compound material has a symmetric structure
Compounds with an asymmetric structure are better than compounds
The effect of sensitization by energy transfer according to the invention is large.
it is considered as. According to the present invention, based on these experimental results,
The mechanism of energy transfer is discussed below. light
The mechanism of energy transfer by chemical reaction is as follows.
Three types are known. (A) Resonance mechanism: energy donor and energy
Due to the interaction between the transition moments of the lugi receptor
And both molecules are separated by more than one medium molecule.
Causes energy transfer. (B) Collision mechanism: energy donor and energy
Caused by the overlap (collision) of the electron cloud of the Luggy receptor
Therefore, the phase shifts at a shorter distance than the resonance mechanism (a).
Interact. (C) Reabsorption mechanism: the energy donor emits
Energy is re-absorbed by the energy receptor
I will. The energy transfer according to the present invention can
If it were due to the harvesting mechanism, energy transfer
Efficiency is not the absolute value of molecular concentration, but the optical density or absorption.
It should depend on luminosity. FIG. 23 shows the data shown in FIG.
The same data as the data is shown.
It is the figure which re-plotted. Smell these samples
Although the molecular concentration is different, the absorption can be adjusted by adjusting the film thickness.
The luminous intensity is set to be almost the same. According to the invention
Energy transfer is due to the above (c) reabsorption mechanism
If so, each sample should be on the same straight line,
As shown in FIG. 23, not the absorbance but the molecular concentration
The effect of the sensitivity increase changes accordingly. Therefore, the present invention
Energy transfer according to the above (c) reabsorption mechanism
It is presumed that it is not a thing. The energy transfer according to the present invention is
(B) If the collision mechanism is used, the molecular concentration is high.
And a specific concentration (the concentration at which the intermolecular distance is less than several Å)
Is considered to have a sudden sensitizing effect when
However, as shown in FIG.
Luggy movement does not exhibit such behavior,
The energy transfer according to the present invention is based on the above (b) collision mechanism.
It is speculated that this is not the case. On the other hand, the above (a) resonance mechanism is shown in FIG.
Can explain the experimental results well,
A photochromic compound of the type
The result that it is easy to obtain the sensitizing effect by moving the lugi is sufficient
Can be explained. That is, asymmetric photo
Chromic compounds have a large dipole moment and
The transition moment is large, and
If this is the case, energy transfer can occur efficiently. Obedience
Is a diarylethene-based photochromic material
The present invention as energy donor and energy acceptor molecules
The energy transfer according to the above is due to the resonance mechanism of (a).
Is presumed to be expressed. In the above embodiment, the photochromic
Compound acts as an energy receptor,
Examples of ring-opened form of a block compound acting as an energy donor
Shows, DPhotochromic as an energy receptor
The molecular structure changes due to energy reception, except for chemical compounds
May be used, and an energy donor may be used.
Other than photochromic compounds to absorb light and
A compound capable of donating energy may be used. Also, energy
When using photochromic compounds as lugi receptors
Even if it is a compound, it is a compound separate from the photochromic compound.
Can be used as energy donor molecules.
In this case, such energy donor molecules have absorption.
Light of a specific wavelength.
It is not necessary for the rhomic compound to be light of a wavelength that has absorption.
No. Hereinafter, as an energy donor molecule, energy
Unlike photochromic compounds that are lug receptor molecules
Used dye moleculesreferenceAn example will be described.Reference example As a photochromic material that becomes an energy acceptor molecule
Is a diarylethene-based photocatalyst shown in
Lomic material was used. [0084] Embedded image FIG. 24 shows this diarylethene photo.
It is a figure which shows the absorption spectrum of a chromic material. Also
The energy donor molecule is shown in the following (Chemical Formula 10).
Cyanine dye (trade name: NK-1532, Nippon Kogaku Dye Co., Ltd.)
Was used. [0086] Embedded image FIG. 25 shows that the above-mentioned dye was added to polystyrene.
It is a figure which shows the absorption spectrum at the time of disperse | distributing. FIG.
As shown in FIG. 5, this dye has λ = 458 nm and
has absorption at λ = 515 nm and λ = 633
There is no absorption at nm. Next, as a sample of an optical recording medium,
0.1 m of the above photochromic material in polystyrene
ol / l, dispersed and thinned, police
Contain the same concentration of the above photochromic material in styrene
And the above dye is dispersed at a concentration of 0.02 mol / l.
Into a thin film and polystyrene.
Photochromic material at the same concentration as
Dye containing 0.05mol / l concentration and dispersed
Three types were prepared. FIG. 26 shows these three types of samples.
FIG. 3 is a diagram showing an absorption spectrum of the present invention. The optical recording medium
Λ = 458n of Ar laser
m, λ = 515 nm, and λ = 633 nm
And the apparent reaction sensitivity ε · k when a ring opening reaction occurs
(L / mol · cm) was determined in the same manner as in Example 1.
Was. In addition, for samples and
The loss due to is compensated. FIG. 27 shows a case where light of λ = 515 nm is irradiated,
It is a figure which shows the reaction sensitivity at the time of performing a ring opening reaction. The horizontal axis is
The absorbance at λ = 620 nm is shown.
The value is proportional to the concentration of the romic ring closed molecule.
The vertical axis indicates the reaction sensitivity ε · k. FIG. 27 (a)
Corresponds to (b) and (c). As shown in FIG.
Photochromic when only the
The compound is an energy donor molecule and an energy acceptor component
Act as a child and react by energy transfer according to the invention
As the reaction progresses (ie, as the absorbance decreases),
The degree is improving. Further, as shown in FIG.
For samples with low concentrations of
In addition to the increase in sensitivity, the overall sensitivity has increased. You
That is, in the early stage of the reaction, 500 to 1000 (l)
/ Mol · cm) is 3000 (l /
mol.cm), which is about three times higher.
In this case, a sensitivity improvement of about twice is observed. Further, as shown in FIG.
For samples with high concentrations of nitrogen,
The reaction sensitivity is extremely high in the
And the sensitivity decreases to 3500 (l / mol · cm)
However, the reaction sensitivity is greatly improved as compared with
From these results, the dye molecule acts as an energy donor.
Photochromic molecules that are energy acceptor molecules
It can be seen that the energy is moving. FIG. 28 is a diagram showing a state where light of λ = 458 nm
The reaction sensitivity at the time of the ring reaction is shown.
(B) corresponds to the sample of (c). Figure
As is clear from FIGS. 28 (a) to 28 (c),
Is that the sensitivity is 1500 (l / mol.
cm) to 2700 (l / mol · cm)
On the other hand, in the sample added with the dye and
500 (l / mol · cm) to 4500 (l / mol)
・ Cm) The sensitivity is greatly improved. Such a result
When the ring opening reaction is performed by irradiating light of λ = 458 nm
In addition, dye molecules act as energy donor molecules,
For photochromic molecules that are energy receptor molecules
That the energy transfer according to the present invention is occurring
You. FIG. 29 shows a case where light of λ = 633 nm is irradiated.
It shows the reaction sensitivity when a ring opening reaction is caused,
(A), (b) and (c) correspond to the sample
are doing. As is clear from FIGS. 28 (a) to (c),
Illuminates light at λ = 633 nm, where the dye molecule has no absorption
In the case of irradiation, even if dye molecules are added, large sensitivity
The above is not recognized, and at such wavelengths,
It can be seen that no energy transfer occurs. The energy transfer according to the present invention contributes.
If not, the reaction sensitivity should be essentially constant,
The decrease in reaction sensitivity in a polymer medium in this way is actually
As described in Example 1, the photochromic molecule
Of the reaction yields a variance in the quantum yield of the reaction.
Probably because [0097] According to the present invention as described above, there is no prior art
New photon mode optical recording can be realized,
The recording sensitivity can be dramatically improved. Therefore,
Systems that record information at high transfer rates, such as high
Optical recording medium used for digital optical disk devices for high-quality moving images
The invention can be applied to the body. Further, the recording laser power has a high power.
Equipment such as a blue semiconductor laser
The present invention can be applied to an optical disk device to be used. FIG.
0 means high recording power has been recently proposed
Using Photon-STM which is not available
FIG. 2 is a diagram illustrating a configuration of an optical memory device according to the first embodiment. Photon-S
About TM, for example, the 11th Japan Society of Applied Physics
Le "Seeing the Micro World" (September 5, 1992)
Strike P. 3-P. 15. "Trends in Super-Optical Microscopy" Gen Otsu
It is explained in detail in one book, and its application to optical recording
Is also described on page 8. Referring to FIG. 30, the photon-STM
Is to enter light from the upper end of the optical probe 1 and
Tip of the optical probe 1 which is guided in the probe 1 and sharply pointed
Substrate using evanescent light 2 oozing from 11
A reaction occurs on the photochromic thin film 4 provided on
A record is made. The evanescent light 2 is applied to the object interface
Light that is localized in the order of the wavelength of the light, in this case
The tip 11 of the probe is attached to the photochromic
The recording is made by approaching the distance. Normal
In optical disk drives, laser light is collected by an objective lens.
Because the light is emitted, the spot diameter must be smaller than the diffraction limit.
And the current recording density of about 1 bit / μm^Two
Could not be significantly improved. Photon-S
In TM, the recording density is determined by the diameter of the probe tip 11.
If the probe tip is made thinner,
However, it is possible to increase the density. At present, about 10^Two~
10 ^Threebit / μm^TwoThe degree is considered possible. In this photon-STM, extremely weak
Since evanescent light is used, practically
Recording speed has not been obtained. The optical recording medium according to the present invention
Since recording can be performed with high sensitivity by using
The light according to the present invention is also used in the photon-STM memory.
Achieving a practical recording speed by using a recording medium
Can be [0102] According to the present invention, light of a specific wavelength is absorbed and absorbed.
Excited state and energy of photochromic compound etc.
-Energy donors that donate energy to acceptor molecules
Inclusion of molecules can greatly improve recording sensitivity.
Can be. Therefore, an apparatus for recording information at a high transfer rate
And it is difficult to obtain high power as the power of the recording laser
Optical recording medium that can be put to practical use in such optical recording devices
And an optical recording method.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram for explaining a reaction mechanism in the present invention. FIG. 2 is a schematic diagram for explaining a conventional one-molecule process reaction mechanism. FIG. 3 shows an absorption spectrum of a spiropyran-based photochromic material. FIG. 4 is a diagram showing an absorption spectrum of a diarylethene-based photochromic material used in Example 1. FIG. 5 is a diagram showing the relationship between the irradiation time of λ = 633 nm light and the absorbance in Example 1. FIG. 6 is a diagram showing the relationship between the irradiation time of λ = 633 nm light and the absorbance in Example 1. FIG. 7 is a diagram showing the relationship between the irradiation time of λ = 515 nm light and the absorbance in Example 1. FIG. 8 is a diagram showing the relationship between the irradiation time of λ = 515 nm light and the absorbance in Example 1. FIG. 9 is a graph showing the relationship between the ring-opened body concentration and ε · k when the concentration of the photochromic material in Example 1 is changed. FIG. 10 is a schematic diagram showing energy transfer from an energy donor when a photochromic compound molecule in Example 1 has a relatively low concentration. FIG. 11 is a schematic diagram showing energy transfer from an energy donor when a photochromic compound molecule in Example 1 has a relatively high concentration. FIG. 12 is a diagram showing the relationship between the irradiation time and the absorbance of light irradiation at λ = 458 nm in Example 1. 13 shows an absorption spectrum of a diarylethene-based photochromic material used in Example 2. FIG. FIG. 14 is a diagram showing the relationship between absorbance and reaction sensitivity in Example 2. FIG. 15 is a graph showing an absorption spectrum of a diarylethene-based photochromic material used in Example 3. FIG. 16 is a graph showing the relationship between absorbance and reaction sensitivity in Example 3. 17 shows an absorption spectrum of a diarylethene-based photochromic material used in Example 4. FIG. FIG. 18 is a graph showing the relationship between absorbance and reaction sensitivity in Example 4. 19 shows an absorption spectrum of a diarylethene-based photochromic material used in Example 5. FIG. FIG. 20 is a graph showing the relationship between absorbance and reaction sensitivity in Example 5. FIG. 21 shows an absorption spectrum of a diarylethene-based photochromic material used in a comparative example. FIG. 22 is a diagram showing the relationship between absorbance and reaction sensitivity in a comparative example. FIG. 23 is a diagram in which the data shown in FIG. 9 is plotted again in the relationship between the absorbance and the reaction sensitivity. FIG. 24 shows an absorption spectrum of a diarylethene-based photochromic material used in a reference example . FIG. 25 is a diagram showing an absorption spectrum of a dye molecule used in a reference example . FIG. 26 shows an absorption spectrum of a thin film containing a photochromic material and a dye molecule manufactured in a reference example . FIG. 27 is a view showing the reaction sensitivity when a ring opening reaction is performed by irradiating light of λ = 515 nm in a reference example . FIG. 28 is a diagram showing the reaction sensitivity when a ring opening reaction is performed by irradiating light of λ = 458 nm in the reference example . FIG. 29 is a diagram showing reaction sensitivity when a ring-opening reaction is performed by irradiating light of λ = 633 nm in a reference example . FIG. 30 is a schematic configuration diagram showing an optical memory device using Photon-STM.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-24245 (JP, A) JP-A-3-75635 (JP, A) JP-A-3-284743 (JP, A) JP-A-5-284 127303 (JP, A) JP-A-6-155889 (JP, A) JP-A-6-167764 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03C 1/73 503

Claims (1)

(57) [Claim 1] Diaryl acting as an energy donor
Ring-opened molecules of ethene-based photochromic compounds and
The diarylethene-based photo acting as a lug receptor
An optical recording medium comprising a chromic compound and a ring-closed molecule,
Waves in which both the open and closed molecule have absorption
A long light is irradiated as recording light to excite the ring-opened molecule.
From the open ring molecule in the excited state to the closed ring molecule
By transferring energy to the
An optical recording method, wherein a ring-opening reaction is caused in a probe to bring it into a recording state .