JPH0422152B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display method that utilizes thermosensitive color change of a film of a diacetylene derivative compound.

[Prior Art] Conventionally, it has been known that a film formed by coating a solution of a diacetylene derivative compound on a carrier and drying it has the following properties.

When the film is polymerized to some extent by irradiating it with ultraviolet rays, the film, which was colorless in its original state, changes to the first state and takes on a blue color. Once it reaches the blue first state, it does not return to its original colorless state even if the UV irradiation is stopped, and the first state is maintained. That is, the change from the original state to the first state due to ultraviolet irradiation is an irreversible change.

Applying thermal energy to the film in the first state
When heated to about 50℃, the blue color changes from the first state to the red second state. Once it is in the red second state, it will not return to the blue first state even if it is cooled, and the change due to heat between the first state and the second state is also an irreversible change.

Furthermore, when thermal energy is applied to the film in the second state and it is heated to about 300°C, it changes from the red second state to the yellow third state. This change between the second state and the third state is a reversible change because even if it changes to the third state by heating, it returns to the original second state when cooled.

Due to the properties of the film of such diacetylene derivative compounds, the film in the second state is used as a display medium, and the reversible change between the second state and the third state is used to create an erasable display (soft copy). This is being studied.

[Problems to be Solved by the Invention] By the way, when soft copying is performed using the thermosensitive change between the second state and the third state of the film of the diacetylene derivative compound described above, the change from the second state to the third state Since a high temperature of about 300°C is required to change the value, there is a problem in that the amount of thermal energy required for display increases. In addition, if the thermal energy is weak, it will take a long time to raise the temperature from room temperature to the high temperature required for display, slowing down the response speed, so a large amount of thermal energy is required at once to obtain a quick response. This results in a further increase in thermal energy consumption.

The present invention provides the following advantages when performing soft copying using the heat-sensitive color change of a film of a diacetylene derivative compound.
The purpose is to enable display with less thermal energy.

[Means for Solving the Problems] The present invention does not form a non-oriented film formed by coating and drying a solution as in the past, but instead forms a diacetylene derivative compound as a monomolecular film. This was achieved by discovering that when an extremely highly ordered alignment film is formed, the change between the first state and the second state becomes a reversible change, as shown in FIG. That is, the greatest feature of the present invention is that the display medium is a monomolecular film of a diacetylene derivative compound that has been polymerized to a first state. Thermal energy is applied to the display medium that has been brought into the first state by changing the display medium to the second state within a range that can maintain a reversible change from the first state.

As the diacetylene derivative in the present invention,
In order to form a monomolecular film, a molecular structure having at least one hydrophilic site, one hydrophobic site, and at least one diacetylene site is used.
For example, it is expressed by the following general formula.

_{R 1} -C≡C-C≡C- _R2 - _X
Examples include polar groups such as a hydroxyl group, an amino group, a nitrile group, a thioalcohol group, an imino group, a sulfone group, a sulfinyl group, and salts thereof, and a typical example is a carboxyl group. Hydrophobic moieties include, for example, straight-chain or branched alkyl groups, olefinic hydrocarbon groups such as vinylene, vinylidene, and acetylene, condensed polycyclic phenyl groups such as phenyl, naphthyl, and anthranyl, and chains of biphenyl and terphenyl groups. Examples thereof include polycyclic phenyl groups, and long-chain alkyl groups are representative. When using a diacetylene derivative compound represented by the above general formula in which this long-chain alkyl group is a hydrophobic moiety, it is easy to obtain a monomolecular film, so the total number of carbon atoms in R ₁ and R ₂ is 10 to 10. A long chain alkyl group of 30, especially 18 or more is preferred.

If the above-mentioned diacetylene derivative compound is used, a monomolecular film can be obtained using the principle of the Langmiur-Blodget method (LB method). That is, when a diacetylene derivative compound is dissolved in a solvent such as chloroform or benzene and dropped onto the water surface, the solution quickly spreads over the water surface.
After the solvent evaporates, a monomolecular film of a diacetylene derivative compound with a two-dimensional molecular arrangement is formed on the water surface with a certain orientation such that the hydrophilic parts face the water phase and the hydrophobic parts move away from the water phase. left behind. Then, by increasing the areal density of this monomolecular film, it can be transferred to a carrier and obtained, and by stacking and transferring the monomolecular film multiple times to the same carrier, the monomolecular film can be obtained. Can be acquired cumulatively.

When transferring a monomolecular film, depending on the transfer method and the type of carrier, the hydrophilic part may face the carrier side, or the hydrophobic part may face the carrier side, but either is acceptable in the present invention. In addition, when obtaining a monolayer in a cumulative manner, depending on the transfer method and type of carrier, an It can be divided into a Y type in which the layers face each other and a Z type in which all the hydrophilic sites in each layer face the carrier side, but either type may be used.

In the present invention, a single monomolecular film or a multilayered monomolecular film may be used, but in order to obtain a clear display with a clear color change, it is preferable to use a film of five or more layers. .

Polymerization for changing the monomolecular film of the diacetylene derivative from the original state to the first state can be performed by irradiating it with ultraviolet rays. This polymerization by ultraviolet irradiation is preferably carried out uniformly so as to exhibit a sufficient blue color. If the polymerization is too low, the color change will be weak and it will be difficult to obtain a clear display. Also,
If the polymerization is excessive, the first state changes to the red second state. Since the change to the second state due to excessive polymerization is an irreversible change, the reversible change due to heat between the first state and the second state cannot be utilized. In polymerization by ultraviolet irradiation, it is usually preferable to achieve a degree of polymerization of about 35 to 45%, but this is just a rough guideline as it varies depending on the type of diacetylene derivative.

Since the change from the colorless original state to the blue first state due to polymerization is an irreversible change as shown in FIG. 1, the first state is maintained even after the ultraviolet irradiation is stopped. In the present invention, a monomolecular film of a diacetylene derivative compound that has been changed from its original state to its first state is used as a display medium.

Display by the display medium is performed by applying thermal energy to change the display medium to the second state. To provide this thermal energy, for example, heat generation from an electric heating element provided adjacent to the display medium, irradiation with an infrared laser, etc. can be used. When thermal energy is applied to the display medium in the first state and its temperature rises, the display medium changes from the first state to the second state, as shown in FIG.
It begins to take on a red color. Therefore, the display is displayed by the contrast between red and blue between the display medium that has been changed to the red second state by applying thermal energy and the display medium that has not been applied thermal energy and remains in the blue first state. can be done. In addition, the change between the first state and the second state is a reversible change, so when the application of thermal energy is stopped and the temperature drops, the display medium that has changed to the second state returns to the first state and displays will be deleted.

The change from the first state to the second state differs depending on the type of diacetylene derivative compound, etc.
It is usually carried out at a temperature of about 30℃ to 100℃. If the temperature is too low, the color change will be insufficient and it will be difficult to obtain a clear display. Furthermore, if the temperature is too high, even if the second state is in the same red color, the display will not return to the original first state even if the application of thermal energy is stopped and the display is cooled, making it impossible to erase the display. Furthermore, if the temperature when changing from the first state to the second state is extremely high, such as 250°C to 300°C or higher, as shown in Figure 1,
The display medium passes through the second state and reaches the yellow third state. Although the change between the second state and the third state is a reversible change, even if the display medium that has reached the third state is cooled, it does not return to the first state, so the display cannot be erased. Therefore, for soft copying, it is necessary to perform the change to the second state at a temperature within a range that can maintain a reversible change from the first state.

[Example] Example 1 Γ Monomolecular film forming apparatus The apparatus used to obtain a monomolecular film of a diacetylene derivative compound is explained with reference to Figs. 2 and 3. In the figure, 1 is a liquid tank; The aqueous phase is housed inside. Inside the liquid tank 1, a frame 2 made of polypropylene that functions as a two-dimensional cylinder is hung horizontally and partitions a water surface 3.

A float 4 made of polypropylene that functions as a two-dimensional piston is floated inside the frame 2. The width of the float 4 is made slightly narrower than the inner width of the frame 2, so that it can move smoothly in the horizontal direction in the figure as a two-dimensional piston.

To move the float 4 to the right, move the float 4 to the pulley 5.
This is done by pulling the weight to the right via the weight 6. The leftward movement and stopping of the float 4 is performed by the repulsive force between a magnet 7 provided on the float 4 and a pair of magnets 8 that can be moved left and right by a holding mechanism (not shown).

Suction nozzles 9 are provided on the left and right sides of the liquid tank 1 for rinsing the liquid surface 3 within the frame 2 to clean the water surface 3. This suction nozzle 9 is connected to a suction pump (not shown) via a suction pipe 10.

Above the water surface 3 on the right side in the figure, carrier upper and lower arms 12 that hold the carrier 11 and are movable in the vertical direction are provided. By this movement of the upper and lower arms of the carrier, the carrier 11 is vertically moved up and down across the water surface 3.

Manufacture of Γ display element Sufficiently clean glass substrate 13 shown in FIG.
2000Å thick indium tein on the surface of
An oxide (ITO) film is formed by sputtering, then photoresist is applied to the film-formed surface, a striped wiring pattern of 16 wires/mm is baked, and the excess ITO is removed by etching.
The film is selectively removed and the remaining portion is used as the lower electrode layer 14.
And so.

Next, a tantalum nitride film with a thickness of 1000 Å was laminated on top of it by the sputtering method, and through the same processing process, 40 μm × 40 μm, 16 pieces each in the vertical and horizontal directions were formed.
A lattice-like dot pattern of mm is formed so as to be laminated on the lower electrode layer 14, and the heating layer 1
I gave it a 5.

On this heat generating layer 15, ITO was formed into a film using the same method as last time, and then photoresist was applied, and 16 wires/mm stripe-like wiring was perpendicular to the lower electrode layer 14, and dot-like wires were formed. After baking was performed so as to pass over the heat generating layer 15, an etching treatment was performed to form the upper electrode layer 16.

The glass substrate 13 provided with the lower electrode layer 14, the heat generating layer 15, and the upper electrode layer 16 was used as the carrier 11 shown in FIGS. 2 and 3, and the LB method was performed using the apparatus shown in the same figures.

First, a diacetylene derivative compound represented by the following formula was added to chloroform at a concentration of 5 x 10 ^-3 mol/distilled water containing cadmium chloride and adjusted to pH 6.3 with sodium hydrogen carbonate on the water surface 3 of the aqueous phase at 20°C. It was dropped and developed.

C ₁₂ H ₂₅ −C≡C−C≡C−C ₈ H ₁₆ −COOH
... After the solvent chloroform was removed by evaporation, the float 4 was moved to reduce the developing area of the monomolecular film left on the water surface 3, and the surface pressure was increased to 20 dyn/cm. Next, while keeping the surface pressure constant,
The monomolecular film was transferred to the surface of the carrier 11 (upper electrode layer 16 side) by gently moving the carrier 11 up and down at a speed of 10 mm/min. The number of monolayer layers to be transferred was 1, 5, 11, 21, 31, and 41. Then, the monomolecular film transferred in this way was exposed to 254 nm ultraviolet rays at 1 mW/cm ²
The display medium layer 1 is irradiated for 1 minute to obtain the first state.
It was set at 7. The obtained display medium layer 17 tended to be darker as the number of accumulated monomolecular layers increased, but all exhibited a blue color.

Implementation of Γ display Upper and lower electrode layers 14 arranged in a matrix,
16, current was passed according to various patterns and the display medium layer 17 was heated by the heat generating layer 15. As a result, the display medium layer 1
7 immediately changed from blue to red, and various patterns were displayed depending on the blue and red colors. When electricity was stopped, the original blue state was immediately returned, and no afterimage was observed, and no change in the display state was observed even after repeated display. Also, if it is between 34℃ and 62℃, it will change from blue to red, and will return to blue as the temperature decreases, but if heated above 62℃, it will be difficult to return from red to blue, and if heated above 250℃ A change to yellow was observed.

Example 2 Γ monolayer forming device The same material as in Example 1 was used.

Manufacture of Γ display element The same procedure as in Example 1 was carried out except that the diacetylene derivative compound represented by the following formula was used.

C ₁₈ H ₃₇ −C≡C−C≡C−C ₈ H ₁₆ −COOH
... The state of the obtained display medium layer 17 was the same as in Example 1.

Implementation of Γ display When carried out in the same manner as in Example 1, similar results were obtained. However, if it is between 40℃ and 80℃, it will change from blue to red and return to blue as the temperature decreases, but if heated above 80℃, it will be difficult to return from red to blue, and if heated above 250℃. A change to yellow was observed.

Example 3 Γ monolayer forming device The same material as in Example 1 was used.

Manufacture of Γ display element A diacetylene derivative compound represented by the following formula was used, and the aqueous phase was only distilled water without additives.

C ₁₈ H ₃₇ -C≡C-C≡C-COOH... Also, as shown in FIG. 5, the glass substrate 13 is used as it is as the carrier 11 shown in FIGS. After the monomolecular film was transferred in the same manner as in Example 1, ultraviolet rays were irradiated to form the display medium layer 17. The state of the obtained display medium layer 17 was the same as in Example 1.

Implementation of Γ display Output 30mW, wavelength for display medium layer 17
When 488 nm argon laser was irradiated according to the pattern, the same results as in Example 1 were obtained. However, if it is between 60℃ and 85℃, it will change from blue to red and return to blue as the temperature decreases, but if heated above 85℃, it will be difficult to return from red to blue, and if heated above 250℃. Then, a change to yellow was observed.

[Effects of the Invention] According to the present invention, display can be performed using a reversible change between a blue first state and a red second state, and this change is made in a relatively low temperature range. Therefore, only a small amount of thermal energy is required for display, and at the same time, a quick response can be achieved using relatively small thermal energy.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the basic principle of the present invention, Figure 2 is an explanatory diagram showing the basic principle of the invention.
The figure is a perspective view of the monomolecular film forming apparatus used in the example.
Figure 3 is a longitudinal cross-sectional view, and Figure 4 is Example 1 and 2.
FIG. 5 is a vertical cross-sectional view of the display element manufactured in Example 3. 1: Liquid tank, 2: Frame, 3: Water surface, 4: Float, 5:
Pulley, 6: Weight, 7: Magnet, 8: Pair magnet, 9: Suction nozzle, 10: Suction pipe, 11: Carrier, 1
2: Carrier upper and lower arms, 13: Glass substrate, 14: Lower electrode layer, 15: Heat generating layer, 16: Upper electrode layer, 1
7: Display medium layer.

Claims (1)

[Claims] 1 A display medium that has been made into a first state by polymerizing a monomolecular film of a diacetylene derivative compound is given thermal energy to change the display medium into a second state within a range that can maintain a reversible change from the first state. A display method characterized by adding.