JP2007245113A - Photosensitive material capable of constructing three-dimensional structure on object surface by light irradiation and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new and useful material for manufacturing a light-emitting device. <P>SOLUTION: A method for constructing a prescribed three-dimensional structure on an object surface by using an organic photochromic compound is to change the object to a first state having a first glass transition temperature by a first light irradiation as the organic photochromic compound and to select the organic photochromic compound which changes the object to a second state having a second glass transition temperature lower than the first glass transition temperature, and is characterized in including a process for planarizing the part where the organic photochromic compound applied by irradiating a desired region with the second light after applying the organic photochromic compound on the object surface and under the temperature lower than the first glass transition temperature and the same level or higher than the second glass transition temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention uses the newly discovered property of an organic photochromic compound capable of reversibly generating two isomers having different states by the action of light, in order to construct a desired three-dimensional structure of the compound on the surface of an article. And a photosensitive material used therefor.

A photochromic compound is a molecule or molecular assembly that reversibly generates two isomers with different states by the action of light. The molecular structure is changed by photochemical reaction, and the light absorption coefficient and refractive index are changed according to this change. The optical properties such as optical rotation and dielectric constant are reversibly changed. In the past, those using the compound include ski goggles in which an organic photochromic compound is dispersed in a synthetic resin such as plastic, and window glasses for sunglasses and automobiles (Patent Document 1, Patent Document 2). etc). Recently, various optical devices using the difference in optical characteristics have been proposed. For example, Patent Document 3 discloses an optical recording medium in which data is recorded and erased by changing the wavelength of light to be irradiated, and data is read by transmittance change (difference in absorbance). An optical switching element using the reversible refractive index change has been proposed, focusing on the fact that the structure changes and the refractive index reversibly changes in accordance with the change in the molecular structure.
Japanese Patent Laid-Open No. 5-65477 JP-A-5-320631 JP 2000-160153 A

  Here, the present inventor has studied various organic photochromic compounds from various angles from the viewpoint of application to optical devices. By the way, when a photochromic compound is applied as a recording layer or an optical switching element of an optical recording medium, it is necessary to form a thin film containing the photochromic compound. Such thin film formation methods include vacuum deposition, coating, and LB (Langmuir-Brodgett) methods. Among them, certain organic photochromic compounds are vacuum-deposited on a diffraction substrate. The present invention has been completed as a result of accidentally discovering a characteristic that has been unknown so far and ascertaining the principle of the characteristic.

  More specifically, when a certain organic photochromic compound was vacuum-deposited on a diffraction substrate having periodically formed grooves, the portion where the organic photochromic compound was deposited in a certain state showed no change in the intensity of diffracted light. However, it turned out that the intensity | strength changes gradually in the site | part where the said organic photochromic compound of another state vapor-deposited. And as a result of searching for the reason that the intensity of this diffracted light changes, the organic photochromic compound in the certain state has a glass transition temperature higher than the ambient temperature, so that the physical shape is maintained, The organic photochromic compound in the different state has a glass transition temperature that is the same as or lower than the ambient temperature, so that the physical shape is maintained as a result of the construction of the active movement of the compound. I found out that I couldn't do it and flattened. And the following invention (1)-(11) is completed by paying attention to the difference of the glass transition temperature of both states.

That is, the present invention (1) is a method for constructing a predetermined three-dimensional structure on an object surface using an organic photochromic compound.
As the organic photochromic compound, the first light irradiation changes to the first state having the first glass transition temperature, while the second light irradiation different from the first light wavelength causes the first light irradiation. Selecting an organic photochromic compound that changes to a second state having a second glass transition temperature lower than the one glass transition temperature;
After applying the organic photochromic compound to the surface of the object, among the sites where the organic photochromic compound is applied, the compound is preliminarily irradiated with the second light on a desired region of the surface, The step of flattening the portion by making it into the second state, or after applying the organic photochromic compound to the object surface, the portion in which the organic photochromic compound is applied is preliminarily in the second state. Irradiating a desired region of the surface with the first light, and making the part into the first state to flatten the part in the second state other than the part; and
The method includes a step of forming a protective film on the surface of the article, which may be present in some cases.

  In the present invention (2), the first glass transition temperature is higher than room temperature, and the second glass transition temperature is the same as or lower than the temperature at which the planarization step is performed (for example, room temperature), It is the method of invention (1). In addition, “similar” in the claims and the present specification means ± 20 ° C., and “normal temperature” means any temperature within 10 to 30 ° C.

  This invention (3) is the method of the said invention (1) or (2) whose difference of said 1st glass transition temperature and said 2nd glass transition temperature is 50 degreeC or more.

の構造を採り、第二状態においては下記式：

の構造を採るジアリールエテン類である、本発明（１）の方法である。 In the present invention (4), the organic photochromic compound is in the first state:

In the second state, the following formula:

In the method of the present invention (1), the diarylethenes having the structure:

  The present invention (5) is the method according to any one of the inventions (1) to (4), wherein the object in which a predetermined three-dimensional structure is constructed is an optical device.

The present invention (6) is a method for producing an object in which a predetermined three-dimensional structure is constructed using an organic photochromic compound.
As the organic photochromic compound, the first light irradiation changes to the first state having the first glass transition temperature, while the second light irradiation different from the first light wavelength causes the first light irradiation. Selecting an organic photochromic compound that changes to a second state having a second glass transition temperature lower than the one glass transition temperature;
After applying the organic photochromic compound to the surface of the object, among the sites where the organic photochromic compound is applied, the compound is preliminarily irradiated with the second light on a desired region of the surface, The step of flattening the portion by making it into the second state, or after applying the organic photochromic compound to the object surface, the portion in which the organic photochromic compound is applied is preliminarily in the second state. Irradiating a desired region of the surface with the first light, and making the part into the first state to flatten the part in the second state other than the part; and
The method includes a step of forming a protective film on the surface of the article, which may be present in some cases.

  In the present invention (7), the first glass transition temperature is higher than room temperature, and the second glass transition temperature is the same as or lower than the temperature at which the planarization step is performed (for example, room temperature). This is the method of the invention (6).

  This invention (8) is the method of the said invention (6) or (7) whose difference of said 1st glass transition temperature and said 2nd glass transition temperature is 50 degreeC or more.

の構造を採り、第二状態においては下記式：

の構造を採るジアリールエテン類である、前記発明（６）の方法である。 In the present invention (9), in the first state, the organic photochromic compound is represented by the following formula:

In the second state, the following formula:

The method according to the invention (6), wherein the diarylethenes having the structure:

  The present invention (10) is the method according to any one of the inventions (6) to (9), wherein the object in which a predetermined three-dimensional structure is constructed is an optical device.

  The present invention (11) changes to the first state having the first glass transition temperature by irradiation with the first light, while the irradiation with the second light different from the wavelength of the first light Photosensitivity used in any one of the above inventions (1) to (10), comprising an organic photochromic compound that changes to a second state having a second glass transition temperature lower than the first glass transition temperature. Material.

  The best mode of the present invention will be described below. First, a photosensitive material according to the present invention will be described, and then a method for using the photosensitive material (a method for manufacturing an article having a predetermined three-dimensional structure) will be described. It should be noted that the present invention is not limited to the following best mode.

  The photosensitive material according to the present invention is changed to the first state having the first glass transition temperature by irradiation with the first light, while being irradiated with the second light different from the wavelength of the first light. The organic photochromic compound which changes to the 2nd state which has a 2nd glass transition temperature lower than said 1st glass transition temperature is contained, It is characterized by the above-mentioned. Hereinafter, each element will be described.

  First, the “photosensitive material” is an organic material having a property of changing its chemical structure when irradiated with light having a wavelength in the range from the ultraviolet light region to the visible light region.

  Next, the organic photochromic compound according to the present invention is changed to a first state having a first glass transition temperature by irradiation with the first light, but second light different from the wavelength of the first light. Irradiation has a property of changing to a second state having a second glass transition temperature lower than the first glass transition temperature. Here, preferably, the glass transition temperature in the second state is at least the same as or lower than the treatment temperature, while the glass transition temperature in the first state is significantly higher than that. Specifically, the difference between the first glass transition temperature and the second glass transition temperature is more preferably 50 ° C. or more. The “glass transition temperature” in this specification is measured by using a differential scanning calorimeter (DSC), and the endothermic process associated with the glass transition when measured at a temperature rising rate of 10 ° C./min from room temperature. The temperature corresponding to the intersection of the slope of the rising portion and the baseline is defined as the glass transition temperature.

Examples of such organic photochromic compounds include the following diarylethenes. Here, in the first state, the diarylethenes have the following formula:

In the second state, the following formula:

The structure of As shown in the absorption spectrum of FIG. 1, this compound undergoes a ring-closing reaction (coloring reaction), for example, by irradiation with ultraviolet light having a wavelength of 365 nm, and also exhibits absorption in the visible region (first state). When this colored compound is irradiated with visible light having a wavelength of, for example, 633 nm, a ring-opening reaction (decoloration reaction) is caused and a second state is obtained. Here, the glass transition temperature in the first state is 90 ° C., whereas the glass transition temperature in the second state is 26 ° C. Therefore, when an amorphous molecular film of the compound is formed, the decolored body molecules can actively move around room temperature (20 ° C.), so that the shape cannot be maintained and flattened under the second state. . In addition, the said compound is a known compound and the manufacturing method is also known.

  Next, a method for using the photosensitive material according to the present invention will be described. The photosensitive material according to the present invention retains its shape in a first state and smoothes in a second state under a predetermined temperature (for example, normal temperature, high temperature region, low temperature region). It is a point. Therefore, when the photosensitive material according to the present invention is applied to the surface of an article, it is preferable to apply the method in such a manner that the shape is maintained in the first state and smoothed in the second state. . That is, first, it is preferable that the surface of the article to which the photosensitive material is applied has a uniform area affected by gravity, and secondly, the area affected by the gravity. When the photosensitive material exists in the second state, it is preferable to apply the photosensitive material to the photosensitive material with a thickness that allows the photosensitive material to be affected by gravity.

  Specifically, first, regarding the former, it is preferable that a uniform uneven pattern (for example, a linear pattern or a dot pattern) is formed on the surface of the article to which the photosensitive material is applied. . When such a pattern is formed, when the photochromic molecular film deposited on the side wall of the pattern is in the second state, a situation in which flattening can easily be established as a result of moving downward by its own weight.

Next, regarding the latter, it is preferable to apply the photosensitive material (organic photochromic compound) to the surface of the article by a vacuum deposition method. At this time, the thickness of the vapor deposition depends on the shape and size of the pattern, but is preferably about 50 nm to 100 nm, for example. In the case of the vacuum deposition method, for example, the diarylethene compound and various additives as necessary are put in a crucible installed in a vacuum vessel, and the inside of the vacuum vessel is 10 ⁻² to 10 ⁻⁵ Pa with a vacuum pump. After evacuating to a certain extent, the crucible is heated to evaporate the components and deposited on a substrate placed facing the crucible to form a photochromic molecular film on the article.

  Then, after irradiating the entire surface of the application surface with first light (for example, ultraviolet light) to fix the molecular film (first state), the second light (for example, laser) is scanned in a desired pattern. It flattens by making the said part into a 2nd state. Alternatively, since this molecular film is normally in the second state immediately after vapor deposition, it is scanned in a desired pattern with the first light to make the part in the first state, and the other state in the other second state Flatten the part. That is, it can be said that these pattern formation techniques are similar to positive resists and negative resists.

If necessary, an arbitrary protective film may be formed thereon for the purpose of stabilization after the planarization process. Here, as the protective film, deposited film of various dielectrics such as TeO _2, and polyvinyl alcohol polymers membranes, or include various metals as gold or Al or the like by vacuum vapor deposition.

  Here, the method can be used for manufacturing various optical devices. For example, a photonic crystal device has been researched and developed as an optical circuit element. A photonic crystal is an artificial crystal whose dielectric constant is periodically modulated, and light in the photonic crystal is subjected to potential scattering due to a periodic change in dielectric constant to form a band structure (photonic band). Research on lossless optical waveguides using this is active. In order to realize periodic dielectric constant modulation, light is lost by partially erasing it in a periodic dielectric pattern (two-dimensional photonic crystal) as shown in FIG. There is a method for forming a waveguide path. In this case, light is guided according to the defect portion. In order to form such a device, it is necessary to create a cell defect portion simultaneously with the formation of a periodic cell, and the degree of freedom in device design is low. However, using this approach, it is possible to make this device more easily. The photochromic molecules of the present invention are vapor-deposited on the substrate on which the uniform periodic pattern shown in FIG. 4 is formed, and immediately colored by ultraviolet light irradiation. In this state, the pattern of the substrate is held on the surface. Next, light such as a laser is irradiated in accordance with a pattern in which light is to be guided (= defects are to be formed) to cause a decoloring reaction. If left as it is for several hours, the isomerized portion is flattened and a cell defect is formed. If a dielectric film is further formed thereon if necessary, the shape of the periodic pattern portion and the flattened portion remaining in the photochromic film is reflected as it is as a dielectric film, and light by a photonic crystal equivalent to FIG. A circuit device can be obtained.

  A photochromic compound having the structural formula shown in FIG. 1 was vapor-deposited with a film thickness of 60 nm on a polycarbonate diffraction grating substrate (groove depth 50 nm, groove pitch 0.8 micron). For this diffraction grating sample, two samples were prepared: one that was sufficiently irradiated with ultraviolet light immediately after vapor deposition (sample 1) and one that was left uncolored without irradiation with ultraviolet light (sample 2). {Under room temperature (20 ° C)}. These were irradiated with laser light having a wavelength of 633 nm at a power of 20 μW (beam diameter: 1 mm), and the change with time in the intensity ratio (diffraction efficiency) of ± 1st order diffracted light to 0th order light was examined. Since the colored sample 1 may cause a photoreaction, care was taken so that the light hits only when measuring the diffraction efficiency. The result is shown in FIG. FIG. 2 shows the change in diffraction efficiency with time, and the horizontal axis represents the elapsed time immediately after the formation of the photochromic film by vacuum deposition. As can be seen, the diffraction efficiency of Sample 1 in the colored state did not change, but the diffraction efficiency of Sample 2 in the decolored state decreased to 1/10 in about 1 hour. This result that the diffraction efficiency decreases suggests that the grooves of the diffraction grating are filling up over time.

  Next, in order to investigate in more detail, the surface of the diffraction grating substrate was observed with AFM. FIG. 3A shows the state of the original substrate surface. The scanning range by AFM is 10 microns × 10 microns. This shows that this substrate has a groove pitch of about 0.8 microns and a groove depth of about 50 nm. With respect to the colored sample 1, a groove shape almost the same as that in FIG. On the other hand, with respect to the sample 2 in the decolored state, it can be seen that after 300 minutes, as shown in FIG. 3B, the groove shape disappears completely and is flattened in the surface roughness range of 2 to 3 nm. This result is obtained by, for example, depositing this photochromic molecular film on a substrate on which a periodic pattern has been formed in advance, coloring the entire surface by ultraviolet light irradiation to fix the pattern, and then scanning with a laser beam or the like. It is shown that the pattern can be erased and only the isomerized pattern portion can be flattened.

  In addition, the temperature (room temperature 20 degreeC) in a planarization process is temperature lower than 26 degreeC which is a glass transition temperature of this compound (2nd state). More desirably, this step is more efficient at 30 to 40 ° C., but if this difference is sufficient, the present invention can be sufficiently implemented {as described above, 20 ° C. above the second glass transition temperature. Up to a low temperature (up to about 6 ° C. in this example) is a temperature at which this step can be performed}.

FIG. 1 shows the absorption spectrum of specific diarylethenes. FIG. 2 shows the change over time in the diffraction efficiency of Sample 1 and Sample 2 in the example. The result of the AFM observation in an Example is shown (FIG. 3-A: Original substrate surface, FIG. 3-B: State of the surface of sample 2). It is an example of the board | substrate with which the periodic pattern was uniformly formed to which this invention can be applied. 5 is an example of an optical circuit device in which the present invention is applied to the substrate of FIG.

Claims (11)

In a method for constructing a predetermined three-dimensional structure on an object surface using an organic photochromic compound,
As the organic photochromic compound, the first light irradiation changes to the first state having the first glass transition temperature, while the second light irradiation is different from the first light wavelength. Selecting an organic photochromic compound that changes to a second state having a second glass transition temperature lower than the one glass transition temperature;
After applying the organic photochromic compound to the surface of the object, among the sites where the organic photochromic compound is applied, the compound is preliminarily irradiated with the second light on a desired region of the surface, The step of flattening the portion by making it into the second state, or after applying the organic photochromic compound to the object surface, the portion in which the organic photochromic compound is applied is preliminarily in the second state. Irradiating a desired region of the surface with the first light to make the part in the first state, thereby flattening the part in the second state other than the part; and
A method comprising forming a protective film on the surface of the object, which may optionally be present.   The method of claim 1, wherein the first glass transition temperature is higher than a temperature at which the planarization step is performed, and the second glass transition temperature is equal to or lower than the temperature.   The method according to claim 1 or 2, wherein a difference between the first glass transition temperature and the second glass transition temperature is 50 ° C or more. In the first state, the organic photochromic compound has the following formula:

In the second state, the following formula:

The method according to claim 1, which is a diarylethene having the following structure:   The method according to claim 1, wherein the object in which a predetermined three-dimensional structure is constructed is an optical device. In a method for producing an object in which a predetermined three-dimensional structure is constructed using an organic photochromic compound,
As the organic photochromic compound, the first light irradiation changes to the first state having the first glass transition temperature, while the second light irradiation different from the first light wavelength causes the first light irradiation. Selecting an organic photochromic compound that changes to a second state having a second glass transition temperature lower than the one glass transition temperature;
After applying the organic photochromic compound to the surface of the object, among the sites where the organic photochromic compound is applied, the compound is preliminarily irradiated with the second light on a desired region of the surface, The step of flattening the portion by making it into the second state, or after applying the organic photochromic compound to the object surface, the portion in which the organic photochromic compound is applied is preliminarily in the second state. Irradiating a desired region of the surface with the first light, and making the part into the first state to flatten the part in the second state other than the part; and
A method comprising forming a protective film on the surface of the object, which may optionally be present.   The method according to claim 6, wherein the first glass transition temperature is higher than a temperature at which the planarization step is performed, and the second glass transition temperature is equal to or lower than the temperature.   The method of Claim 6 or 7 that the difference of said 1st glass transition temperature and said 2nd glass transition temperature is 50 degreeC or more. In the first state, the organic photochromic compound has the following formula:

In the second state, the following formula:

The method according to claim 6, which is a diarylethene having the following structure:   The method according to claim 6, wherein the object in which a predetermined three-dimensional structure is constructed is an optical device. While the first light changes to the first state having the first glass transition temperature, the second light irradiation is different from the first glass transition temperature. The photosensitive material used for the method of any one of Claims 1-10 containing the organic photochromic compound which changes to the 2nd state which has a low 2nd glass transition temperature.

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