JPH06175165A - Color tone-changing gel and optical element, display board and educational equipment using the same - Google Patents

Abstract

PURPOSE:To obtain a new optical material and educational equipment for science by using a color tone-changing gel whose color is changed by external stimuli. CONSTITUTION:In the color tone-changing gel, its color is changed by external stimuli. In this case, any gel having a property of changing the color corresponding to various stimuli such as the temperature, humidity, voltage and pressure therein, or any gel to which such property is given, may be used as a gel whose color is changed by the external stimuli. Then, the high molecular gel 2 and an electrode 3 swelled in an electrolytic aq. solution in which an indicator is dissolved are arranged at the inside of an optical cell 1, a part of whose front face is transparent. When the DC voltage is applied from a power source 4, cations in the gel are diffused toward a negative electrode, thus the pH value in the vicinity of the negative electrode is increased and the color of the indicator is changed. Further, the color of the indicator is turned to the original color by reversing the positive and negative of the DC voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color tone changing gel, an optical element and a display board using the same, and a science educational device. More specifically, the present invention relates to a gel whose color is changed by an external stimulus such as pH and The present invention relates to optical elements, display boards, and educational equipment for science using the same.

[0002]

2. Description of the Related Art Currently, as optical materials for display panels,
Liquid crystal materials are widely used. Liquid crystal display (LCD)
Are generally low in drive voltage and low in power consumption.

On the other hand, although much research has been conducted on gels that respond to various stimuli, little attention has been paid to changes in gel color tone and application of gels to optical materials. To give a strong example, a liquid layer containing a liquid-absorbing colored gel that absorbs liquid at high temperature and discharges liquid at low temperature and a liquid, and an infrared beam and an infrared absorption layer for giving thermal energy to this liquid layer A device is proposed in Japanese Patent Laid-Open No. 61-151625. Further, an optical element in which a gel-containing liquid layer of a liquid absorbing and absorbing polymer having a dye that swells or contracts due to temperature change is sandwiched between a pair of substrates having a resistance heating layer is disclosed in JP-A-62-927. Proposed.

[0004]

Generally, in a simple matrix type LCD using a super twisted nematic effect,
Controlling the gap of the liquid crystal cell in units of 0.1 micron,
High production technology such as aligning the liquid crystal molecular axes at a constant angle to the glass surface of the cell is required. On the other hand, an active matrix type LCD using a thin film transistor element or the like requires a high-level thin film processing technique, and the yield at the manufacturing stage is low. Although the cost of the LCD is currently being reduced due to mass production, it cannot be said that the LCD is so inexpensive because of the above reasons and the liquid crystal material itself being expensive.

Further, the optical element proposed in Japanese Patent Laid-Open No. 61-151625 makes use of the difference in the concentration of dye contained in the colored gel when the gel is swollen and when the gel is shrunk. Not to mention the change in the gel color due to the change, nor was it focused on it. Also, the swelling of gel
Since the shrinkage is performed by changing the temperature, the heat generation amount becomes large, it is difficult to control the heat conduction, and the problem of durability due to repeated swelling / shrinkage is not clarified.

Further, the optical element proposed in Japanese Patent Laid-Open No. 62-927 also utilizes the difference in the concentration of dye contained in the colored gel when the gel is swollen and when the gel is shrunk. Not to mention the change in gel color due to pH change, it is not the one that paid attention to it.

An object of the present invention is to provide a completely new gel for changing the color tone by changing the pH inside the gel, a novel optical element using the gel, a display plate, and a science educational device.

[0008]

In order to achieve the object of the present invention, the following constitution is adopted. That is, the color-tone changing gel of the present invention is characterized in that the color is changed by an external stimulus.

The optical element of the present invention is characterized by comprising the above-mentioned color tone changing gel and a stimulus transmitting mechanism for transmitting an external stimulus to the gel.

Further, the display plate of the present invention is characterized by comprising the above-mentioned color change gel and a stimulus transmission mechanism for transmitting an external stimulus to the gel.

Further, the science educational device of the present invention is characterized by comprising the above-mentioned color change gel and a stimulus transmitting mechanism for transmitting an external stimulus to the gel.

[0012]

The gel used in the present invention is not particularly limited as long as it is a cross-linked polymer compound. Specifically, polyacrylic acid, polymethacrylic acid, polyfumaric acid, polyitaconic acid, polyacrylamide, polyvinyl alcohol, polyacrylonitrile, polyacrylate, polymethacrylate, polyfumarate, polyitaconate, Organic polymer gels such as polymaleimide-based, polystyrene-based, polyvinyl ether-based, polyurethane-based, polysulfone-based, polyester-based, polyamide-based, and polysiloxane-based, and inorganic polymers such as titanium compound-based and zirconia compound-based A gel or the like can be used.

The gel whose color is changed by an external stimulus in the present invention is a gel having a property of changing color in response to various stimuli such as temperature, humidity, voltage and pressure among these gels, Alternatively, any gel can be used as long as it has such properties. Particularly, a gel whose color changes with a change in pH is preferably used because the change is vivid.

The present invention will be described below by typifying a gel that changes color with a change in pH.

In the present invention, the substance whose color changes with a change in pH is a compound having a function of changing from colorless to colored, from colored to colorless, or from one color to another in a specific pH range. There is no particular limitation. Specifically, indicators such as thymol blue, phenolphthalein, methyl red, bromothymol blue, phenol red, and congo red can be used.

The pH of the gel due to external stimulus in the present invention
The substance that changes pH is a substance that exists inside the gel and causes a pH gradient inside the gel by diffusing inside the gel by an external stimulus. As a specific example, an aqueous solution of an electrolyte such as lithium chloride, sodium chloride, sodium sulfate and potassium chloride can be used. Further, the external stimulus in the present invention is not particularly limited as long as it is an environmental change such as temperature, solvent exchange, electricity, electric field, magnetism, magnetic field, light irradiation or a combination thereof.

The following is an example of the gel of the present invention whose color is changed by an external stimulus. An indicator as a substance whose color changes with pH change, an electrolyte aqueous solution as a substance that changes the pH of the gel by an external stimulus, and a DC voltage is applied to the gel as an external stimulus, the cations in the electrolyte inside the gel Is attracted to the negative electrode and the anion is attracted to the positive electrode, and a pH gradient occurs inside the gel. As a result, the color of the gel changes from colorless to colored, from colored to colorless, or from one color to another due to the indicator inside the gel. The color of the gel depends on the direction of application of the DC voltage, and the color change can be repeated by switching the positive and negative of the DC voltage. Further, the color of the gel is retained for a long time even after the application of the DC voltage is stopped.

Each of the optical element, the display board and the educational equipment for science in the present invention comprises a gel whose color is changed by an external stimulus and a stimulus transmission mechanism for transmitting the external stimulus to the gel. The change in gel color is the operating principle of optical elements, display boards, and educational equipment for science.

As the external stimulus transmitting mechanism in the present invention, a mechanism transmitting an environmental change such as temperature, solvent exchange, electricity, electric field, magnetism, magnetic field, light irradiation or a combination thereof can be used. However, an electric transmission mechanism is particularly preferable because the device can be simplified.

The electric transmission mechanism of the present invention comprises a power source and electrodes. The power source is not particularly limited as long as it generates a constant voltage, but a DC power source is preferable. The electrode is not particularly limited as long as it does not dissolve or corrode in an acidic, neutral or alkaline electrolyte solution, and a metal foil, a metal thin film, a metal wire, a transparent conductive film, a transparent conductive plate or the like can be used. .

The display plate of the present invention is one in which one of the optical elements of the present invention is enlarged, or a large number of the optical elements are arranged at a level usable as a display plate.

When a large number of optical elements are arranged in a display panel, the method of arranging the optical elements is not particularly limited.
Arranging with a certain regularity is preferable because a clear image can be displayed. As a concrete arrangement method, an assembly of one or several optical elements is arranged parallel to each side when the shape of the display plate is a triangle, a quadrangle, etc., and radially when the shape is a circle, a sphere, an ellipse, etc. Moreover, it is good to arrange them at equal intervals. In these cases, the width and accuracy of the space are appropriately determined depending on the size of the display plate and the purpose of use.

A light incident device can be used for the display panel of the present invention. The light incident device that can be used for the display panel of the present invention is not particularly limited, and any type such as a radiation type, a reflection type, and a refraction type can be used.
Further, the color of the light source is not particularly limited, and any light such as white light or monochromatic light can be used. The number of light sources is not particularly limited, and may be one, or one optical element or several optical elements. Further, it may be used after being split, condensed, polarized, etc. by a prism, a lens or the like. Further, in the educational device for science obtained by the present invention, an indicator is a substance whose color is changed by a pH change, an aqueous solution of an electrolyte is a substance which changes the pH of the gel by an external stimulus, and a stimulus transmission for transmitting the external stimulus to the gel part. When a direct current power source and two electrodes are used as the mechanism, it is possible to observe how the cations in the electrolyte move toward the negative electrode and the anions move toward the positive electrode in the electrolyte as voltage changes. In this case, it is desirable to use a dry battery as the DC power source, considering that the operation is simple and the place of use is not limited. Such science education equipment,
An optical element made of a color change gel is enlarged or arranged in a large number so that it can be used as a device, and is further systematized.

Next, examples of the optical element, the display board, and the educational equipment for science of the present invention will be described with reference to the drawings, but of course the invention is not limited to these.

FIG. 1 shows an example of the optical element of the present invention.
A polymer gel 2 and an electrode 3 swollen in an aqueous electrolyte solution in which an indicator is dissolved are placed inside an optical cell 1 whose front surface is partially transparent. When a DC voltage is applied from the power source 4, the cations inside the gel diffuse toward the negative electrode, so that the pH near the negative electrode increases and the color of the indicator changes. The color of the indicator is restored by reversing the sign of the DC voltage. Moreover, the color of the indicator is retained for a long time even after the voltage application is stopped. The change of the two color states can be repeated, and the function as an optical element is exhibited by this principle.

FIG. 2 shows an example of the display panel of the present invention. In FIG. 2, the optical elements 5 of FIG. 1 are arranged vertically and horizontally, and light is emitted from the back surface by one backlight 6. The control circuit 7 controls the potential of each optical element to form an image.

FIG. 3 shows an example of the educational device for science of the present invention. The system of FIG. 3 comprises a gel holder 9 with 3 and a dry battery box 11. 9 has a groove 10 for fixing a plurality of gels.
A voltage is applied to the gel by connecting the lead wire from the to the terminal 13, and the indicator inside the gel is discolored. Since the voltage can be applied to a plurality of gels at the same time by using 9, it is possible to compare the difference in color and discoloration speed depending on the type of the indicator and the electrolyte aqueous solution contained in the gel and the crosslinking density of the gel. . In addition, since the number of dry batteries 11 can be selected in the range of 1 to several depending on the connection position of 13, it is also possible to observe the change in discoloration speed due to the amount of electricity. Here, the educational equipment for science is a general term for educational equipment including toys.

[0028]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. That is, in the present invention, the concept of a change in gel color due to a change in pH inside the gel, an optical material using the change, and an educational device for science are important. Those who know this technical idea will find it easy to change to a more efficient product.

Example 1 Bromothymol blue was dissolved in a rod-shaped polyacrylamide gel synthesized by heating a mixture of 35 g of acrylamide, 0.8 g of methylenebisacrylamide, 1.1 g of ammonium persulfate and 150 g of ion-exchanged water to 60 ° C. It was swollen for 24 hours in an aqueous sodium chloride solution (concentration of sodium chloride 0.1 mol / L). The obtained yellow gel was fixed inside a closed cell made of glass and plastic, and further two platinum electrodes were arranged so as to contact the gel to produce an optical cell. When a DC voltage (1 to 10 V) was applied to this optical cell, the color observed on the front surface of the cell changed from yellow to blue. When the positive and negative signs of the applied voltage were reversed, the color returned to yellow. This color change was repeatable. Further, there was no change in color when the voltage application was stopped.

Example 2 A rod-shaped polyacrylamide gel synthesized in the same manner as in Example 1 was swollen for 24 hours in a lithium chloride aqueous solution (lithium chloride concentration 0.1 mol / L) in which phenol red was dissolved. When an optical cell similar to that of Example 1 was prepared using the obtained yellow gel and a DC voltage was applied, the color observed on the front surface of the cell changed from yellow to red. As in Example 1, the color change is repeatable, and
The color was retained when the voltage application was stopped.

[0031]

INDUSTRIAL APPLICABILITY As described above, the present invention provides the pH inside the gel.
By utilizing the change in gel color due to the change, it is possible to obtain a new optical material and a science educational device.

The gel whose color is changed by an external stimulus obtained in the present invention is based on a change in gel color due to a pH change inside the gel as an operating principle, and does not require volume change of the gel itself such as swelling / contraction. Excellent durability against repeated color changes. In addition, it is possible to obtain various colors by selecting a substance such as an indicator whose color changes with a change in pH.

Further, in the gel of the present invention whose color is changed by an external stimulus, although the color change speed of the gel due to the pH change inside the gel is smaller than the response speed of the liquid crystal, the gel remains unchanged for a certain period of time after the stimulus is removed. It has the characteristic of retaining color, that is, having a memory effect. Therefore, it is possible to save power consumption when energy for giving a stimulus to the gel, for example, a direct current voltage is used as a stimulus.

Since the optical element, the display board and the educational equipment for science obtained by the present invention use the gel whose color is changed by the above external stimulus, it has all the characteristics of the gel. That is, the optical element, the display plate obtained in the present invention,
Educational equipment for science is much more excellent in repeated durability than (1) optical elements that operate by swelling / shrinking gel, and (2) clear gel color changes due to pH change inside the gel. The contrast is very good because changes can be obtained. (3) Multicolor display is possible by selecting a substance whose color changes with pH change, such as an indicator. (4) Constant after removing the stimulus. It has a memory function of time and is characterized by being able to save energy for giving a stimulus.

Further, the optical element and the display plate of the present invention have a simple structure and do not require a strict constitution such as a liquid crystal cell, and therefore they are easy to manufacture, and further, the gel and other materials used are LCD because it is cheap
It can be supplied at a much lower cost than Also,
Since the structure is simple and strict dimensional stability is not required, the display board of the present invention can be formed into a sheet shape that can be bent or rolled.

Further, in the science educational device obtained by the present invention, an indicator is used as a substance whose color is changed by a pH change, an aqueous solution of an electrolyte is used as a substance which changes the pH of the gel by an external stimulus, and an external stimulus is applied to the gel part. When using a DC power supply and two electrodes as a stimulus transmission mechanism,
(1) It is possible to observe that the cations in the electrolyte move toward the negative electrode and the anions move toward the positive electrode when a voltage is applied, as a color change of the indicator, and the concept of diffusion can be recognized by the color change. , (2) The difference in discoloration rate when the type of the aqueous electrolyte solution is changed can be recognized, and (3) the difference in discoloration rate due to the cross-linking density of gel or the amount of electricity is compared. It is possible to obtain a high educational effect such as (4) the fun is attracted by the fact that different colors are obtained depending on the kind of the indicator contained in the gel.

Further, in the educational device for science of the present invention, by using the dry battery as the DC power source, it is possible to operate it safely and easily and easily, so that it can be used in a wide range of age groups. is there.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an optical element of the present invention.

FIG. 2 is a schematic view showing an example of a display plate of the present invention.

FIG. 3 is a schematic view showing an example of a science educational device of the present invention.

[Explanation of symbols]

 1: Cell 2: Gel 3: Electrode 4: DC power supply 5: Optical element 6: Backlight 7: Control circuit 8: Image input interface 9: Gel holder 10: Gel fixing groove 11: Dry battery box 12: Dry battery 13: Terminal

Claims (13)

[Claims] 1. A color-tone changing gel whose color is changed by an external stimulus. 2. The color-changing gel according to claim 1, wherein the gel contains a substance whose color is changed by an external stimulus. 3. The color change gel according to claim 1, wherein the gel contains a substance whose color changes with a change in pH and a substance which changes the pH of the gel by an external stimulus. 4. The color-tone changing gel according to claim 3, wherein the substance whose color changes with a change in pH is an indicator. 5. The color-tone changing gel according to claim 3, wherein the substance that changes the pH of the gel portion by external stimulation is an aqueous electrolyte solution. 6. An optical element comprising the color-tone changing gel according to claim 1 and a stimulus transmitting mechanism for transmitting an external stimulus to the gel. 7. The optical element according to claim 6, wherein the stimulus transmission mechanism includes a DC power source and two electrodes. 8. A display plate comprising the color-tone changing gel according to claim 1 and a stimulus transmitting mechanism for transmitting an external stimulus to the gel. 9. The display panel according to claim 8, wherein the stimulus transmission mechanism includes a DC power source and two electrodes. 10. A display plate comprising the optical element according to claim 6 arranged therein. 11. The display panel according to claim 8, further comprising a light incident device. 12. A science educational device comprising the color-tone changing gel according to claim 1 and a stimulus transmitting mechanism for transmitting an external stimulus to the gel. 13. The educational machine for science according to claim 12, wherein the stimulus transmission mechanism is composed of a DC power supply and two electrodes.